/*      $NetBSD: if_spppsubr.c,v 1.305 2026/07/14 06:01:50 yamaguchi Exp $       */

/*
 * Synchronous PPP/Cisco link level subroutines.
 * Keepalive protocol implemented in both Cisco and PPP modes.
 *
 * Copyright (C) 1994-1996 Cronyx Engineering Ltd.
 * Author: Serge Vakulenko, <vak@cronyx.ru>
 *
 * Heavily revamped to conform to RFC 1661.
 * Copyright (C) 1997, Joerg Wunsch.
 *
 * RFC2472 IPv6CP support.
 * Copyright (C) 2000, Jun-ichiro itojun Hagino <itojun@iijlab.net>.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE FREEBSD PROJECT OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * From: Version 2.4, Thu Apr 30 17:17:21 MSD 1997
 *
 * From: if_spppsubr.c,v 1.39 1998/04/04 13:26:03 phk Exp
 *
 * From: Id: if_spppsubr.c,v 1.23 1999/02/23 14:47:50 hm Exp
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: if_spppsubr.c,v 1.305 2026/07/14 06:01:50 yamaguchi Exp $");

#if defined(_KERNEL_OPT)
#include "opt_inet.h"
#include "opt_modular.h"
#include "opt_compat_netbsd.h"
#include "opt_net_mpsafe.h"
#include "opt_sppp.h"
#endif

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/sockio.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/callout.h>
#include <sys/md5.h>
#include <sys/inttypes.h>
#include <sys/kauth.h>
#include <sys/cprng.h>
#include <sys/module.h>
#include <sys/workqueue.h>
#include <sys/atomic.h>
#include <sys/compat_stub.h>
#include <sys/cpu.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/ppp_defs.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#ifdef INET
#include <netinet/ip.h>
#include <netinet/tcp.h>
#endif
#include <net/ethertypes.h>

#ifdef INET6
#include <netinet6/scope6_var.h>
#endif

#include <net/if_sppp.h>
#include <net/if_spppvar.h>

#ifdef NET_MPSAFE
#define SPPPSUBR_MPSAFE 1
#endif

#define DEFAULT_KEEPALIVE_INTERVAL      10      /* seconds between checks */
#define DEFAULT_ALIVE_INTERVAL          1       /* count of sppp_keepalive */
#define LOOPALIVECNT                    3       /* loopback detection tries */
#define DEFAULT_MAXALIVECNT             3       /* max. missed alive packets */
#define DEFAULT_NORECV_TIME             15      /* before we get worried */
#define DEFAULT_MAX_AUTH_FAILURES       5       /* max. auth. failures */

#ifndef SPPP_KEEPALIVE_INTERVAL
#define SPPP_KEEPALIVE_INTERVAL         DEFAULT_KEEPALIVE_INTERVAL
#endif

#ifndef SPPP_NORECV_TIME
#define SPPP_NORECV_TIME        DEFAULT_NORECV_TIME
#endif

#ifndef SPPP_ALIVE_INTERVAL
#define SPPP_ALIVE_INTERVAL             DEFAULT_ALIVE_INTERVAL
#endif

#define SPPP_CPTYPE_NAMELEN     5       /* buf size of cp type name */
#define SPPP_AUTHTYPE_NAMELEN   32      /* buf size of auth type name */
#define SPPP_LCPOPT_NAMELEN     5       /* buf size of lcp option name  */
#define SPPP_IPCPOPT_NAMELEN    5       /* buf size of ipcp option name */
#define SPPP_IPV6CPOPT_NAMELEN  5       /* buf size of ipv6cp option name */
#define SPPP_PROTO_NAMELEN      7       /* buf size of protocol name */
#define SPPP_DOTQUAD_BUFLEN     16      /* length of "aa.bb.cc.dd" */

/*
 * Interface flags that can be set in an ifconfig command.
 *
 * Setting link0 will make the link passive, i.e. it will be marked
 * as being administrative openable, but won't be opened to begin
 * with.  Incoming calls will be answered, or subsequent calls with
 * -link1 will cause the administrative open of the LCP layer.
 *
 * Setting link1 will cause the link to auto-dial only as packets
 * arrive to be sent.
 *
 * Setting IFF_DEBUG will syslog the option negotiation and state
 * transitions at level kern.debug.  Note: all logs consistently look
 * like
 *
 *   <if-name><unit>: <proto-name> <additional info...>
 *
 * with <if-name><unit> being something like "bppp0", and <proto-name>
 * being one of "lcp", "ipcp", "cisco", "chap", "pap", etc.
 */

#define IFF_PASSIVE     IFF_LINK0       /* wait passively for connection */
#define IFF_AUTO        IFF_LINK1       /* auto-dial on output */

#define CONF_REQ        1               /* PPP configure request */
#define CONF_ACK        2               /* PPP configure acknowledge */
#define CONF_NAK        3               /* PPP configure negative ack */
#define CONF_REJ        4               /* PPP configure reject */
#define TERM_REQ        5               /* PPP terminate request */
#define TERM_ACK        6               /* PPP terminate acknowledge */
#define CODE_REJ        7               /* PPP code reject */
#define PROTO_REJ       8               /* PPP protocol reject */
#define ECHO_REQ        9               /* PPP echo request */
#define ECHO_REPLY      10              /* PPP echo reply */
#define DISC_REQ        11              /* PPP discard request */

#define LCP_OPT_MRU             1       /* maximum receive unit */
#define LCP_OPT_ASYNC_MAP       2       /* async control character map */
#define LCP_OPT_AUTH_PROTO      3       /* authentication protocol */
#define LCP_OPT_QUAL_PROTO      4       /* quality protocol */
#define LCP_OPT_MAGIC           5       /* magic number */
#define LCP_OPT_RESERVED        6       /* reserved */
#define LCP_OPT_PROTO_COMP      7       /* protocol field compression */
#define LCP_OPT_ADDR_COMP       8       /* address/control field compression */
#define LCP_OPT_FCS_ALTS        9       /* FCS alternatives */
#define LCP_OPT_SELF_DESC_PAD   10      /* self-describing padding */
#define LCP_OPT_CALL_BACK       13      /* callback */
#define LCP_OPT_COMPOUND_FRMS   15      /* compound frames */
#define LCP_OPT_MP_MRRU         17      /* multilink MRRU */
#define LCP_OPT_MP_SSNHF        18      /* multilink short seq. numbers */
#define LCP_OPT_MP_EID          19      /* multilink endpoint discriminator */

#define IPCP_OPT_ADDRESSES      1       /* both IP addresses; deprecated */
#define IPCP_OPT_COMPRESSION    2       /* IP compression protocol */
#define IPCP_OPT_ADDRESS        3       /* local IP address */
#define IPCP_OPT_PRIMDNS        129     /* primary remote dns address */
#define IPCP_OPT_SECDNS         131     /* secondary remote dns address */

#define IPCP_UPDATE_LIMIT       8       /* limit of pending IP updating job */
#define IPCP_SET_ADDRS          1       /* marker for IP address setting job */
#define IPCP_CLEAR_ADDRS        2       /* marker for IP address clearing job */

#define IPV6CP_OPT_IFID         1       /* interface identifier */
#define IPV6CP_OPT_COMPRESSION  2       /* IPv6 compression protocol */

#define PAP_REQ                 1       /* PAP name/password request */
#define PAP_ACK                 2       /* PAP acknowledge */
#define PAP_NAK                 3       /* PAP fail */

#define CHAP_CHALLENGE          1       /* CHAP challenge request */
#define CHAP_RESPONSE           2       /* CHAP challenge response */
#define CHAP_SUCCESS            3       /* CHAP response ok */
#define CHAP_FAILURE            4       /* CHAP response failed */

#define CHAP_MD5                5       /* hash algorithm - MD5 */

#define CISCO_MULTICAST         0x8f    /* Cisco multicast address */
#define CISCO_UNICAST           0x0f    /* Cisco unicast address */
#define CISCO_KEEPALIVE         0x8035  /* Cisco keepalive protocol */
#define CISCO_ADDR_REQ          0       /* Cisco address request */
#define CISCO_ADDR_REPLY        1       /* Cisco address reply */
#define CISCO_KEEPALIVE_REQ     2       /* Cisco keepalive request */

#define PPP_NOPROTO             0       /* no authentication protocol */

enum {
        STATE_INITIAL = SPPP_STATE_INITIAL,
        STATE_STARTING = SPPP_STATE_STARTING,
        STATE_CLOSED = SPPP_STATE_CLOSED,
        STATE_STOPPED = SPPP_STATE_STOPPED,
        STATE_CLOSING = SPPP_STATE_CLOSING,
        STATE_STOPPING = SPPP_STATE_STOPPING,
        STATE_REQ_SENT = SPPP_STATE_REQ_SENT,
        STATE_ACK_RCVD = SPPP_STATE_ACK_RCVD,
        STATE_ACK_SENT = SPPP_STATE_ACK_SENT,
        STATE_OPENED = SPPP_STATE_OPENED,
};

enum cp_rcr_type {
        CP_RCR_NONE = 0,        /* initial value */
        CP_RCR_ACK,     /* RCR+ */
        CP_RCR_NAK,     /* RCR- */
        CP_RCR_REJ,     /* RCR- */
        CP_RCR_DROP,    /* DROP message */
        CP_RCR_ERR,     /* internal error */
};

struct ppp_header {
        uint8_t address;
        uint8_t control;
        uint16_t protocol;
} __packed;
#define PPP_HEADER_LEN          sizeof (struct ppp_header)

struct lcp_header {
        uint8_t type;
        uint8_t ident;
        uint16_t len;
} __packed;
#define LCP_HEADER_LEN          sizeof (struct lcp_header)

struct cisco_packet {
        uint32_t type;
        uint32_t par1;
        uint32_t par2;
        uint16_t rel;
        uint16_t time0;
        uint16_t time1;
} __packed;
#define CISCO_PACKET_LEN 18

/*
 * We follow the spelling and capitalization of RFC 1661 here, to make
 * it easier comparing with the standard.  Please refer to this RFC in
 * case you can't make sense out of these abbreviation; it will also
 * explain the semantics related to the various events and actions.
 */
struct cp {
        u_short proto;          /* PPP control protocol number */
        u_char protoidx;        /* index into state table in struct sppp */
        u_char flags;
#define CP_LCP          0x01    /* this is the LCP */
#define CP_AUTH         0x02    /* this is an authentication protocol */
#define CP_NCP          0x04    /* this is a NCP */
#define CP_QUAL         0x08    /* this is a quality reporting protocol */
        const char *name;       /* name of this control protocol */
        /* event handlers */
        void    (*Up)(struct sppp *, void *);
        void    (*Down)(struct sppp *, void *);
        void    (*Open)(struct sppp *, void *);
        void    (*Close)(struct sppp *, void *);
        void    (*TO)(struct sppp *, void *);
        /* actions */
        void    (*tlu)(struct sppp *);
        void    (*tld)(struct sppp *);
        void    (*tls)(const struct cp *, struct sppp *);
        void    (*tlf)(const struct cp *, struct sppp *);
        void    (*scr)(struct sppp *);
        void    (*screply)(const struct cp *, struct sppp *, u_char,
                    uint8_t, size_t, void *);

        /* message parser */
        enum cp_rcr_type
                (*parse_confreq)(struct sppp *, struct lcp_header *, int,
                            uint8_t **, size_t *, size_t *);
        void    (*parse_confrej)(struct sppp *, struct lcp_header *, int);
        void    (*parse_confnak)(struct sppp *, struct lcp_header *, int);
};

enum auth_role {
        SPPP_AUTH_NOROLE = 0,
        SPPP_AUTH_SERV = __BIT(0),
        SPPP_AUTH_PEER = __BIT(1),
};

static struct sppp      *spppq;
static kmutex_t         *spppq_lock = NULL;
static callout_t         keepalive_ch;
static unsigned int      sppp_keepalive_cnt = 0;
unsigned int             sppp_keepalive_interval __read_mostly
                            = SPPP_KEEPALIVE_INTERVAL;

pktq_rps_hash_func_t sppp_pktq_rps_hash_p;

#define SPPPQ_LOCK()    if (spppq_lock) \
                                mutex_enter(spppq_lock);
#define SPPPQ_UNLOCK()  if (spppq_lock) \
                                mutex_exit(spppq_lock);

#define SPPP_LOCK(_sp, _op)     rw_enter(&(_sp)->pp_lock, (_op))
#define SPPP_UNLOCK(_sp)        rw_exit(&(_sp)->pp_lock)
#define SPPP_WLOCKED(_sp)       rw_write_held(&(_sp)->pp_lock)
#define SPPP_WQ_SET(_wk, _func, _arg)   \
        sppp_wq_set((_wk), (_func), __UNCONST((_arg)))
#define SPPP_LOG(_sp, _lvl, _fmt, _args...)     do {            \
        if (__predict_true((_sp) != NULL)) {                    \
                log((_lvl), "%s: ", (_sp)->pp_if.if_xname);     \
        }                                                       \
        addlog((_fmt), ##_args);                                \
} while (0)
#define SPPP_DLOG(_sp, _fmt, _args...)  do {    \
        if (!sppp_debug_enabled(_sp))                   \
                break;                                  \
        SPPP_LOG(_sp, LOG_DEBUG, _fmt, ##_args);        \
} while (0)

#ifdef INET
#ifndef SPPPSUBR_MPSAFE
/*
 * The following disgusting hack gets around the problem that IP TOS
 * can't be set yet.  We want to put "interactive" traffic on a high
 * priority queue.  To decide if traffic is interactive, we check that
 * a) it is TCP and b) one of its ports is telnet, rlogin or ftp control.
 *
 * XXX is this really still necessary?  - joerg -
 */
static u_short interactive_ports[8] = {
        0,      513,    0,      0,
        0,      21,     0,      23,
};
#define INTERACTIVE(p)  (interactive_ports[(p) & 7] == (p))
#endif /* SPPPSUBR_MPSAFE */
#endif

/* almost every function needs these */

static bool sppp_debug_enabled(struct sppp *sp);
static int sppp_output(struct ifnet *, struct mbuf *,
                       const struct sockaddr *, const struct rtentry *);

static void sppp_cp_init(const struct cp *, struct sppp *);
static void sppp_cp_fini(const struct cp *, struct sppp *);
static void sppp_cp_input(const struct cp *, struct sppp *,
                          struct mbuf *);
static void sppp_cp_send(struct sppp *, u_short, u_char,
                         u_char, u_short, void *);
/* static void sppp_cp_timeout(void *arg); */
static void sppp_cp_change_state(const struct cp *, struct sppp *, int);
static struct workqueue *
    sppp_wq_create(struct sppp *, const char *, pri_t, int, int);
static void sppp_wq_destroy(struct sppp *, struct workqueue *);
static void sppp_wq_set(struct sppp_work *,
    void (*)(struct sppp *, void *), void *);
static void sppp_wq_add(struct workqueue *, struct sppp_work *);
static void sppp_wq_wait(struct workqueue *, struct sppp_work *);
static void sppp_cp_to_lcp(void *);
static void sppp_cp_to_ipcp(void *);
static void sppp_cp_to_ipv6cp(void *);
static void sppp_auth_send(const struct cp *, struct sppp *,
                            unsigned int, unsigned int, ...);
static int sppp_auth_role(const struct cp *, struct sppp *);
static void sppp_auth_to_event(struct sppp *, void *);
static void sppp_auth_screply(const struct cp *, struct sppp *,
                            u_char, uint8_t, size_t, void *);
static void sppp_up_event(struct sppp *, void *);
static void sppp_down_event(struct sppp *, void *);
static void sppp_open_event(struct sppp *, void *);
static void sppp_close_event(struct sppp *, void *);
static void sppp_to_event(struct sppp *, void *);
static void sppp_rcr_event(struct sppp *, void *);
static void sppp_rca_event(struct sppp *, void *);
static void sppp_rcn_event(struct sppp *, void *);
static void sppp_rtr_event(struct sppp *, void *);
static void sppp_rta_event(struct sppp *, void *);
static void sppp_rxj_event(struct sppp *, void *);

static void sppp_null(struct sppp *);
static void sppp_tls(const struct cp *, struct sppp *);
static void sppp_tlf(const struct cp *, struct sppp *);
static void sppp_screply(const struct cp *, struct sppp *,
                    u_char, uint8_t, size_t, void *);
static void sppp_ifdown(struct sppp *, void *);

static void sppp_lcp_init(struct sppp *);
static void sppp_lcp_up(struct sppp *, void *);
static void sppp_lcp_down(struct sppp *, void *);
static void sppp_lcp_open(struct sppp *, void *);
static enum cp_rcr_type
            sppp_lcp_confreq(struct sppp *, struct lcp_header *, int,
                    uint8_t **, size_t *, size_t *);
static void sppp_lcp_confrej(struct sppp *, struct lcp_header *, int);
static void sppp_lcp_confnak(struct sppp *, struct lcp_header *, int);
static void sppp_lcp_tlu(struct sppp *);
static void sppp_lcp_tld(struct sppp *);
static void sppp_lcp_tls(const struct cp *, struct sppp *);
static void sppp_lcp_tlf(const struct cp *, struct sppp *);
static void sppp_lcp_scr(struct sppp *);
static void sppp_lcp_check_and_close(struct sppp *);
static int sppp_cp_check(struct sppp *, u_char);
static bool sppp_is_ncp_opened(struct sppp *);

static void sppp_ipcp_init(struct sppp *);
static void sppp_ipcp_open(struct sppp *, void *);
static void sppp_ipcp_close(struct sppp *, void *);
static enum cp_rcr_type
            sppp_ipcp_confreq(struct sppp *, struct lcp_header *, int,
                    uint8_t **, size_t *, size_t *);
static void sppp_ipcp_confrej(struct sppp *, struct lcp_header *, int);
static void sppp_ipcp_confnak(struct sppp *, struct lcp_header *, int);
static void sppp_ipcp_tlu(struct sppp *);
static void sppp_ipcp_tld(struct sppp *);
static void sppp_ipcp_scr(struct sppp *);

static void sppp_ipv6cp_init(struct sppp *);
static void sppp_ipv6cp_open(struct sppp *, void *);
static enum cp_rcr_type
            sppp_ipv6cp_confreq(struct sppp *, struct lcp_header *, int,
                    uint8_t **, size_t *, size_t *);
static void sppp_ipv6cp_confrej(struct sppp *, struct lcp_header *, int);
static void sppp_ipv6cp_confnak(struct sppp *, struct lcp_header *, int);
static void sppp_ipv6cp_tlu(struct sppp *);
static void sppp_ipv6cp_tld(struct sppp *);
static void sppp_ipv6cp_scr(struct sppp *);

static void sppp_pap_input(struct sppp *, struct mbuf *);
static void sppp_pap_init(struct sppp *);
static void sppp_pap_tlu(struct sppp *);
static void sppp_pap_scr(struct sppp *);

static void sppp_chap_input(struct sppp *, struct mbuf *);
static void sppp_chap_init(struct sppp *);
static void sppp_chap_open(struct sppp *, void *);
static void sppp_chap_tlu(struct sppp *);
static void sppp_chap_scr(struct sppp *);
static void sppp_chap_rcv_challenge_event(struct sppp *, void *);

static const char *sppp_auth_type_name(char *, size_t, u_short, u_char);
static const char *sppp_cp_type_name(char *, size_t, u_char);
static const char *sppp_dotted_quad(char *, size_t, uint32_t);
static const char *sppp_ipcp_opt_name(char *, size_t, u_char);
#ifdef INET6
static const char *sppp_ipv6cp_opt_name(char *, size_t, u_char);
#endif
static const char *sppp_lcp_opt_name(char *, size_t, u_char);
static const char *sppp_phase_name(int);
static const char *sppp_proto_name(char *, size_t, u_short);
static const char *sppp_state_name(int);
static int sppp_params(struct sppp *, u_long, void *);
#ifdef INET
static void sppp_get_ip_addrs(struct sppp *, uint32_t *, uint32_t *, uint32_t *);
static void sppp_set_ip_addrs(struct sppp *);
static void sppp_clear_ip_addrs(struct sppp *);
#endif
static void sppp_keepalive(void *);
static void sppp_phase_network(struct sppp *);
static void sppp_print_bytes(const u_char *, u_short);
static void sppp_print_string(const char *, u_short);
#ifdef INET6
static void sppp_get_ip6_addrs(struct sppp *, struct in6_addr *,
                                struct in6_addr *, struct in6_addr *);
#ifdef IPV6CP_MYIFID_DYN
static void sppp_set_ip6_addr(struct sppp *, const struct in6_addr *);
static void sppp_gen_ip6_addr(struct sppp *, const struct in6_addr *);
#endif
static void sppp_suggest_ip6_addr(struct sppp *, struct in6_addr *);
#endif

static void sppp_notify_up(struct sppp *);
static void sppp_notify_down(struct sppp *);
static void sppp_notify_tls_wlocked(struct sppp *);
static void sppp_notify_tlf_wlocked(struct sppp *);

/* our control protocol descriptors */
static const struct cp lcp = {
        PPP_LCP, IDX_LCP, CP_LCP, "lcp",
        sppp_lcp_up, sppp_lcp_down, sppp_lcp_open,
        sppp_close_event, sppp_to_event,
        sppp_lcp_tlu, sppp_lcp_tld, sppp_lcp_tls,
        sppp_lcp_tlf, sppp_lcp_scr, sppp_screply,
        sppp_lcp_confreq, sppp_lcp_confrej, sppp_lcp_confnak
};

static const struct cp ipcp = {
        PPP_IPCP, IDX_IPCP,
#ifdef INET
        CP_NCP, /*don't run IPCP if there's no IPv4 support*/
#else
        0,
#endif
        "ipcp",
        sppp_up_event, sppp_down_event, sppp_ipcp_open,
        sppp_ipcp_close, sppp_to_event,
        sppp_ipcp_tlu, sppp_ipcp_tld, sppp_tls,
        sppp_tlf, sppp_ipcp_scr, sppp_screply,
        sppp_ipcp_confreq, sppp_ipcp_confrej, sppp_ipcp_confnak,
};

static const struct cp ipv6cp = {
        PPP_IPV6CP, IDX_IPV6CP,
#ifdef INET6    /*don't run IPv6CP if there's no IPv6 support*/
        CP_NCP,
#else
        0,
#endif
        "ipv6cp",
        sppp_up_event, sppp_down_event, sppp_ipv6cp_open,
        sppp_close_event, sppp_to_event,
        sppp_ipv6cp_tlu, sppp_ipv6cp_tld, sppp_tls,
        sppp_tlf, sppp_ipv6cp_scr, sppp_screply,
        sppp_ipv6cp_confreq, sppp_ipv6cp_confrej, sppp_ipv6cp_confnak,
};

static const struct cp pap = {
        PPP_PAP, IDX_PAP, CP_AUTH, "pap",
        sppp_up_event, sppp_down_event, sppp_open_event,
        sppp_close_event, sppp_auth_to_event,
        sppp_pap_tlu, sppp_null, sppp_tls, sppp_tlf,
        sppp_pap_scr, sppp_auth_screply,
        NULL, NULL, NULL
};

static const struct cp chap = {
        PPP_CHAP, IDX_CHAP, CP_AUTH, "chap",
        sppp_up_event, sppp_down_event, sppp_chap_open,
        sppp_close_event, sppp_auth_to_event,
        sppp_chap_tlu, sppp_null, sppp_tls, sppp_tlf,
        sppp_chap_scr, sppp_auth_screply,
        NULL, NULL, NULL
};

static const struct cp *cps[IDX_COUNT] = {
        &lcp,                   /* IDX_LCP */
        &ipcp,                  /* IDX_IPCP */
        &ipv6cp,                /* IDX_IPV6CP */
        &pap,                   /* IDX_PAP */
        &chap,                  /* IDX_CHAP */
};

static inline u_int
sppp_proto2authproto(u_short proto)
{

        switch (proto) {
        case PPP_PAP:
                return SPPP_AUTHPROTO_PAP;
        case PPP_CHAP:
                return SPPP_AUTHPROTO_CHAP;
        }

        return SPPP_AUTHPROTO_NONE;
}

static inline u_short
sppp_authproto2proto(u_int authproto)
{

        switch (authproto) {
        case SPPP_AUTHPROTO_PAP:
                return PPP_PAP;
        case SPPP_AUTHPROTO_CHAP:
                return PPP_CHAP;
        }

        return PPP_NOPROTO;
}

static inline bool
sppp_debug_enabled(struct sppp *sp)
{

        if (__predict_false(sp == NULL))
                return false;

        if ((sp->pp_if.if_flags & IFF_DEBUG) == 0)
                return false;

        return true;
}

static inline void
sppp_connect(struct sppp *sp)
{
        KASSERT(SPPP_WLOCKED(sp));

        sp->pp_if.if_flags |= IFF_RUNNING;
        atomic_store_relaxed(&sp->pp_connecting, true);
        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_open);
}

static inline void
sppp_disconnect(struct sppp *sp)
{
        KASSERT(SPPP_WLOCKED(sp));

        sp->pp_if.if_flags &= ~IFF_RUNNING;
        atomic_store_relaxed(&sp->pp_connecting, false);
        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_close);
}

static void
sppp_change_phase(struct sppp *sp, int phase)
{
        struct ifnet *ifp = &sp->pp_if;

        KASSERT(SPPP_WLOCKED(sp));

        if (sp->pp_phase == phase)
                return;

        sp->pp_phase = phase;

        if (phase == SPPP_PHASE_NETWORK)
                if_link_state_change(ifp, LINK_STATE_UP);
        else
                if_link_state_change(ifp, LINK_STATE_DOWN);

        SPPP_DLOG(sp, "phase %s\n",
            sppp_phase_name(sp->pp_phase));
}

/*
 * Exported functions, comprising our interface to the lower layer.
 */

/*
 * Process the received packet.
 */
void
sppp_input(struct ifnet *ifp, struct mbuf *m)
{
        struct ppp_header *h = NULL;
        pktqueue_t *pktq = NULL;
        uint16_t protocol;
        struct sppp *sp = (struct sppp *)ifp;

        /* No RPS for not-IP. */
        pktq_rps_hash_func_t rps_hash = NULL;

        if (ifp->if_flags & IFF_UP) {
                /* Count received bytes, add hardware framing */
                if_statadd(ifp, if_ibytes, m->m_pkthdr.len + sp->pp_framebytes);
                /* Note time of last receive */
                atomic_store_relaxed(&sp->pp_last_receive, time_uptime32);
        }

        if (m->m_pkthdr.len <= PPP_HEADER_LEN) {
                /* Too small packet, drop it. */
                SPPP_DLOG(sp, "input packet is too small, "
                    "%d bytes\n", m->m_pkthdr.len);
                goto error;
        }

        if (ISSET(sp->pp_dev_flags, PP_DEVF_NOFRAMING)) {
                memcpy(&protocol, mtod(m, void *), 2);
                protocol = ntohs(protocol);
                m_adj(m, 2);
        } else {

                /* Get PPP header. */
                h = mtod(m, struct ppp_header *);
                m_adj(m, PPP_HEADER_LEN);

                switch (h->address) {
                case PPP_ALLSTATIONS:
                        if (h->control != PPP_UI)
                                goto invalid;
                        break;
                case CISCO_MULTICAST:
                case CISCO_UNICAST:
                        /* Don't check the control field here (RFC 1547). */
                        SPPP_DLOG(sp, "Cisco packet in PPP mode "
                            "<addr=0x%x ctrl=0x%x proto=0x%x>\n",
                            h->address, h->control, ntohs(h->protocol));
                        goto drop;
                default:        /* Invalid PPP packet. */
                  invalid:
                        SPPP_DLOG(sp, "invalid input packet "
                            "<addr=0x%x ctrl=0x%x proto=0x%x>\n",
                            h->address, h->control, ntohs(h->protocol));
                        goto drop;
                }
                protocol = ntohs(h->protocol);
        }

        switch (protocol) {
        reject_protocol:
                KASSERT(SPPP_WLOCKED(sp));

                if (sp->scp[IDX_LCP].state == STATE_OPENED) {
                        uint16_t prot = htons(protocol);

                        sppp_cp_send(sp, PPP_LCP, PROTO_REJ,
                            ++sp->scp[IDX_LCP].seq, sizeof(prot), &prot);
                }
                SPPP_UNLOCK(sp);
                goto noproto;
        default:
                SPPP_DLOG(sp, "invalid input protocol "
                    "<proto=0x%x>\n", protocol);
                goto reject_protocol;
        case PPP_LCP:
                SPPP_LOCK(sp, RW_WRITER);
                sppp_cp_input(&lcp, sp, m);
                /* already m_freem(m) */
                SPPP_UNLOCK(sp);
                return;
        case PPP_PAP:
                SPPP_LOCK(sp, RW_WRITER);
                if (sp->pp_phase >= SPPP_PHASE_AUTHENTICATE) {
                        sppp_pap_input(sp, m);
                } else {
                        SPPP_UNLOCK(sp);
                        goto drop;
                }
                SPPP_UNLOCK(sp);
                m_freem(m);
                return;
        case PPP_CHAP:
                SPPP_LOCK(sp, RW_WRITER);
                if (sp->pp_phase >= SPPP_PHASE_AUTHENTICATE) {
                        sppp_chap_input(sp, m);
                } else {
                        SPPP_UNLOCK(sp);
                        goto drop;
                }
                SPPP_UNLOCK(sp);
                m_freem(m);
                return;
#ifdef INET
        case PPP_IPCP:
                SPPP_LOCK(sp, RW_WRITER);
                if (!ISSET(sp->pp_ncpflags, SPPP_NCP_IPCP)) {
                        SPPP_LOG(sp, LOG_INFO, "reject IPCP packet "
                            "because IPCP is disabled\n");
                        goto reject_protocol;
                }
                if (sp->pp_phase == SPPP_PHASE_NETWORK) {
                        sppp_cp_input(&ipcp, sp, m);
                        /* already m_freem(m) */
                } else {
                        SPPP_UNLOCK(sp);
                        goto drop;
                }
                SPPP_UNLOCK(sp);
                return;
        case PPP_IP:
                SPPP_LOCK(sp, RW_READER);
                if (sp->scp[IDX_IPCP].state == STATE_OPENED) {
                        atomic_store_relaxed(&sp->pp_last_activity, time_uptime32);
                        pktq = ip_pktq;
                        rps_hash = atomic_load_relaxed(&sppp_pktq_rps_hash_p);
                }
                SPPP_UNLOCK(sp);
                break;
#endif
#ifdef INET6
        case PPP_IPV6CP:
                SPPP_LOCK(sp, RW_WRITER);
                if (!ISSET(sp->pp_ncpflags, SPPP_NCP_IPV6CP)) {
                        SPPP_LOG(sp, LOG_INFO, "reject IPv6CP packet "
                            "because IPv6CP is disabled\n");
                        goto reject_protocol;
                }
                if (sp->pp_phase == SPPP_PHASE_NETWORK) {
                        sppp_cp_input(&ipv6cp, sp, m);
                        /* already m_freem(m) */
                } else {
                        SPPP_UNLOCK(sp);
                        goto drop;
                }
                SPPP_UNLOCK(sp);
                return;

        case PPP_IPV6:
                SPPP_LOCK(sp, RW_READER);
                if (sp->scp[IDX_IPV6CP].state == STATE_OPENED) {
                        atomic_store_relaxed(&sp->pp_last_activity, time_uptime32);
                        pktq = ip6_pktq;
                        rps_hash = atomic_load_relaxed(&sppp_pktq_rps_hash_p);
                }
                SPPP_UNLOCK(sp);
                break;
#endif
        }

        if ((ifp->if_flags & IFF_UP) == 0 || pktq == NULL) {
                goto drop;
        }

        /* Check queue. */
        const uint32_t hash = rps_hash ? pktq_rps_hash(&rps_hash, m) : 0;
        if (__predict_false(!pktq_enqueue(pktq, m, hash))) {
                goto drop;
        }
        return;

drop:
        if_statinc(ifp, if_iqdrops);
        m_freem(m);
        return;

error:
        if_statinc(ifp, if_ierrors);
        m_freem(m);
        return;

noproto:
        if_statinc(ifp, if_noproto);
        m_freem(m);
        return;
}

/*
 * Enqueue transmit packet.
 */
static int
sppp_output(struct ifnet *ifp, struct mbuf *m,
    const struct sockaddr *dst, const struct rtentry *rt)
{
        struct sppp *sp = (struct sppp *) ifp;
        struct ppp_header *h = NULL;
#ifndef SPPPSUBR_MPSAFE
        struct ifqueue *ifq = NULL;             /* XXX */
#endif
        int error = 0;
        uint16_t protocol;
        size_t pktlen;

        atomic_store_relaxed(&sp->pp_last_activity, time_uptime32);

        if ((ifp->if_flags & IFF_UP) == 0) {
                m_freem(m);
                if_statinc(ifp, if_oerrors);
                return (ENETDOWN);
        }

        if (!sppp_is_connecting(ifp)) {
                SPPP_LOCK(sp, RW_WRITER);
                if (!sp->pp_ondemand) {
                        SPPP_UNLOCK(sp);
                        m_freem(m);
                        if_statinc(ifp, if_oerrors);
                        return (ENETDOWN);
                } else {
                        /* ignore packets that have no enabled NCP */
                        if ((dst->sa_family == AF_INET &&
                            !ISSET(sp->pp_ncpflags, SPPP_NCP_IPCP)) ||
                            (dst->sa_family == AF_INET6 &&
                            !ISSET(sp->pp_ncpflags, SPPP_NCP_IPV6CP))) {
                                SPPP_UNLOCK(sp);

                                m_freem(m);
                                if_statinc(ifp, if_oerrors);
                                return (ENETDOWN);
                        }
                        /*
                         * Interface is not yet running, but auto-dial.  Need
                         * to start LCP for it.
                         * Re-check sp->pp_connecting
                         * under lock (Double-Checked Locking)
                         */
                        if (!sp->pp_connecting)
                                sppp_connect(sp);
                }
                SPPP_UNLOCK(sp);
        }

        /*
         * If the queueing discipline needs packet classification,
         * do it before prepending link headers.
         */
        IFQ_CLASSIFY(&ifp->if_snd, m, dst->sa_family);

#ifdef INET
        if (dst->sa_family == AF_INET) {
                struct ip *ip = NULL;
#ifndef SPPPSUBR_MPSAFE
                struct tcphdr *th = NULL;
#endif

                if (m->m_len >= sizeof(struct ip)) {
                        ip = mtod(m, struct ip *);
#ifndef SPPPSUBR_MPSAFE
                        if (ip->ip_p == IPPROTO_TCP &&
                            m->m_len >= sizeof(struct ip) + (ip->ip_hl << 2) +
                            sizeof(struct tcphdr)) {
                                th = (struct tcphdr *)
                                    ((char *)ip + (ip->ip_hl << 2));
                        }
#endif
                } else
                        ip = NULL;

                /*
                 * When using dynamic local IP address assignment by using
                 * 0.0.0.0 as a local address, the first TCP session will
                 * not connect because the local TCP checksum is computed
                 * using 0.0.0.0 which will later become our real IP address
                 * so the TCP checksum computed at the remote end will
                 * become invalid. So we
                 * - don't let packets with src ip addr 0 thru
                 * - we flag TCP packets with src ip 0 as an error
                 */
                if (ip && ip->ip_src.s_addr == INADDR_ANY) {
                        uint8_t proto = ip->ip_p;

                        m_freem(m);
                        if (proto == IPPROTO_TCP)
                                return (EADDRNOTAVAIL);
                        else
                                return (0);
                }

#ifndef SPPPSUBR_MPSAFE
                /*
                 * Put low delay, telnet, rlogin and ftp control packets
                 * in front of the queue.
                 */
                if (!IF_QFULL(&sp->pp_fastq) &&
                    ((ip && (ip->ip_tos & IPTOS_LOWDELAY)) ||
                     (th && (INTERACTIVE(ntohs(th->th_sport)) ||
                      INTERACTIVE(ntohs(th->th_dport))))))
                        ifq = &sp->pp_fastq;
#endif /* !SPPPSUBR_MPSAFE */
        }
#endif

#ifdef INET6
        if (dst->sa_family == AF_INET6) {
                /* XXX do something tricky here? */
        }
#endif

        if (!ISSET(sp->pp_dev_flags, PP_DEVF_NOFRAMING)) {
                /*
                 * Prepend general data packet PPP header. For now, IP only.
                 */
                M_PREPEND(m, PPP_HEADER_LEN, M_DONTWAIT);
                if (! m) {
                        SPPP_DLOG(sp, "no memory for transmit header\n");
                        if_statinc(ifp, if_oerrors);
                        return (ENOBUFS);
                }
                /*
                 * May want to check size of packet
                 * (albeit due to the implementation it's always enough)
                 */
                h = mtod(m, struct ppp_header *);
                h->address = PPP_ALLSTATIONS;        /* broadcast address */
                h->control = PPP_UI;                 /* Unnumbered Info */
        }

        switch (dst->sa_family) {
#ifdef INET
        case AF_INET:   /* Internet Protocol */
                /*
                 * Don't choke with an ENETDOWN early.  It's
                 * possible that we just started dialing out,
                 * so don't drop the packet immediately.  If
                 * we notice that we run out of buffer space
                 * below, we will however remember that we are
                 * not ready to carry IP packets, and return
                 * ENETDOWN, as opposed to ENOBUFS.
                 */
                protocol = htons(PPP_IP);
                SPPP_LOCK(sp, RW_READER);
                if (sp->scp[IDX_IPCP].state != STATE_OPENED) {
                        if (ifp->if_flags & IFF_AUTO) {
                                error = ENETDOWN;
                        } else {
                                SPPP_UNLOCK(sp);

                                m_freem(m);
                                if_statinc(ifp, if_oerrors);
                                return (ENETDOWN);
                        }
                }
                SPPP_UNLOCK(sp);
                break;
#endif
#ifdef INET6
        case AF_INET6:   /* Internet Protocol version 6 */
                /*
                 * Don't choke with an ENETDOWN early.  It's
                 * possible that we just started dialing out,
                 * so don't drop the packet immediately.  If
                 * we notice that we run out of buffer space
                 * below, we will however remember that we are
                 * not ready to carry IP packets, and return
                 * ENETDOWN, as opposed to ENOBUFS.
                 */
                protocol = htons(PPP_IPV6);
                SPPP_LOCK(sp, RW_READER);
                if (sp->scp[IDX_IPV6CP].state != STATE_OPENED) {
                        if (ifp->if_flags & IFF_AUTO) {
                                error = ENETDOWN;
                        } else {
                                SPPP_UNLOCK(sp);

                                m_freem(m);
                                if_statinc(ifp, if_oerrors);
                                return (ENETDOWN);
                        }
                }
                SPPP_UNLOCK(sp);
                break;
#endif
        default:
                m_freem(m);
                if_statinc(ifp, if_oerrors);
                return (EAFNOSUPPORT);
        }

        if (error == ENETDOWN) {
                IF_DROP(&ifp->if_snd);
                m_freem(m);
                return error;
        }

        if (ISSET(sp->pp_dev_flags, PP_DEVF_NOFRAMING)) {
                M_PREPEND(m, 2, M_DONTWAIT);
                if (m == NULL) {
                        SPPP_DLOG(sp, "no memory for transmit header\n");
                        if_statinc(ifp, if_oerrors);
                        return (ENOBUFS);
                }
                *mtod(m, uint16_t *) = protocol;
        } else {
                h->protocol = protocol;
        }

        pktlen = m->m_pkthdr.len;
#ifdef SPPPSUBR_MPSAFE
        error = if_transmit_lock(ifp, m);
        if (error == 0)
                if_statadd(ifp, if_obytes, pktlen + sp->pp_framebytes);
#else /* !SPPPSUBR_MPSAFE */
        error = ifq_enqueue2(ifp, ifq, m);

        if (error == 0) {
                /*
                 * Count output packets and bytes.
                 * The packet length includes header + additional hardware
                 * framing according to RFC 1333.
                 */
                if (!(ifp->if_flags & IFF_OACTIVE)) {
                        if_start_lock(ifp);
                }
                if_statadd(ifp, if_obytes, pktlen + sp->pp_framebytes);
        }
#endif /* !SPPPSUBR_MPSAFE */
        return error;
}

static int
sppp_sysctl_flags(SYSCTLFN_ARGS)
{
        struct sppp *sp = rnode->sysctl_data;
        const char *s = rnode->sysctl_name;
        struct sysctlnode node;
        int err, val;
        u_int flag;

        if (strcmp(s, "ifdown") == 0) {
                flag = PP_IFDOWN;
        } else {
                return EINVAL;
        }

        SPPP_LOCK(sp, RW_READER);
        val = (sp->pp_flags & flag) ? 1 : 0;
        SPPP_UNLOCK(sp);

        node = *rnode;
        node.sysctl_data = &val;

        err = sysctl_lookup(SYSCTLFN_CALL(&node));
            if (err || newp == NULL)
                return err;

        SPPP_LOCK(sp, RW_WRITER);
        if (val == 1) {
                sp->pp_flags |= flag;
        } else {
                sp->pp_flags &= ~flag;
        }
        SPPP_UNLOCK(sp);

        return 0;
}

static void
sppp_sysctl_setup(struct sppp *sp)
{
        struct sysctllog **clog = &sp->pp_sysctl_log;
        const struct sysctlnode *rnode = NULL, *cnode = NULL;
        int err;

        err = sysctl_createv(clog, 0, NULL, &rnode,
            CTLFLAG_PERMANENT,
            CTLTYPE_NODE, "sppp",
            SYSCTL_DESCR("Synchronous Point-to-Point Protocol controls"),
            NULL, 0, NULL, 0,
            CTL_NET, CTL_CREATE, CTL_EOL);
        if (err != 0)
                goto bad;

        err = sysctl_createv(clog, 0, &rnode, &rnode,
            CTLFLAG_PERMANENT,
            CTLTYPE_NODE, sp->pp_if.if_xname,
            SYSCTL_DESCR("Interface controls"),
            NULL, 0, NULL, 0,
            CTL_CREATE, CTL_EOL);
        if (err != 0)
                goto bad;

        err = sysctl_createv(clog, 0, &rnode, &cnode,
            CTLFLAG_PERMANENT | CTLFLAG_READWRITE,
            CTLTYPE_BOOL, "ifdown",
            SYSCTL_DESCR("Down interface on no echo reply and loopback detected"),
            sppp_sysctl_flags, 0, (void *)sp, 0,
            CTL_CREATE, CTL_EOL);
        if (err != 0)
                goto bad;

        return;
bad:
        sysctl_teardown(&sp->pp_sysctl_log);
        SPPP_LOG(sp, LOG_WARNING,
            "could not attach sysctl nodes for sppp\n");
        return;
}

void
sppp_attach(struct ifnet *ifp)
{
        struct sppp *sp = (struct sppp *) ifp;
        char xnamebuf[MAXCOMLEN];

        /* Initialize keepalive handler. */
        if (! spppq) {
                callout_init(&keepalive_ch, CALLOUT_MPSAFE);
                callout_setfunc(&keepalive_ch, sppp_keepalive, NULL);
                callout_schedule(&keepalive_ch, hz * sppp_keepalive_interval);
        }

        if (! spppq_lock)
                spppq_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_SOFTNET);

        sp->pp_if.if_type = IFT_PPP;
        sp->pp_if.if_output = sppp_output;
        IFQ_SET_MAXLEN(&sp->pp_fastq, 32);
        IFQ_LOCK_INIT(&sp->pp_fastq);
        IFQ_SET_MAXLEN(&sp->pp_cpq, 20);
        sp->pp_loopcnt = 0;
        sp->pp_alivecnt = 0;
        sp->pp_alive_interval = SPPP_ALIVE_INTERVAL;
        sp->pp_last_activity = 0;
        sp->pp_last_receive = 0;
        sp->pp_maxalive = DEFAULT_MAXALIVECNT;
        sp->pp_max_noreceive = SPPP_NORECV_TIME;
        sp->pp_idle_timeout = 0;
        sp->pp_max_auth_fail = DEFAULT_MAX_AUTH_FAILURES;
        sp->pp_phase = SPPP_PHASE_DEAD;
        sp->pp_up = sppp_notify_up;
        sp->pp_down = sppp_notify_down;
        sp->pp_ncpflags = SPPP_NCP_IPCP | SPPP_NCP_IPV6CP;
#ifdef SPPP_IFDOWN_RECONNECT
        sp->pp_flags |= PP_IFDOWN;
#endif
        sppp_wq_set(&sp->work_ifdown, sppp_ifdown, NULL);
        memset(sp->scp, 0, sizeof(sp->scp));
        rw_init(&sp->pp_lock);
        sppp_sysctl_setup(sp);

        if_alloc_sadl(ifp);

        /* Lets not beat about the bush, we know we're down. */
        if_link_state_change(ifp, LINK_STATE_DOWN);

        snprintf(xnamebuf, sizeof(xnamebuf), "%s.wq_cp", ifp->if_xname);
        sp->wq_cp = sppp_wq_create(sp, xnamebuf,
            PRI_SOFTNET, IPL_SOFTNET, WQ_MPSAFE);

        memset(&sp->myauth, 0, sizeof sp->myauth);
        memset(&sp->hisauth, 0, sizeof sp->hisauth);
        SPPP_LOCK(sp, RW_WRITER);
        sppp_lcp_init(sp);
        sppp_ipcp_init(sp);
        sppp_ipv6cp_init(sp);
        sppp_pap_init(sp);
        sppp_chap_init(sp);
        SPPP_UNLOCK(sp);

        SPPPQ_LOCK();
        /* Insert new entry into the keepalive list. */
        sp->pp_next = spppq;
        spppq = sp;
        SPPPQ_UNLOCK();
}

void
sppp_detach(struct ifnet *ifp)
{
        struct sppp **q, *p, *sp = (struct sppp *) ifp;

        /* Remove the entry from the keepalive list. */
        SPPPQ_LOCK();
        for (q = &spppq; (p = *q); q = &p->pp_next)
                if (p == sp) {
                        *q = p->pp_next;
                        break;
                }
        SPPPQ_UNLOCK();

        if (! spppq) {
                /* Stop keepalive handler. */
                callout_stop(&keepalive_ch);
                mutex_obj_free(spppq_lock);
                spppq_lock = NULL;
        }

        sysctl_teardown(&sp->pp_sysctl_log);
        sppp_cp_fini(&lcp, sp);
        sppp_cp_fini(&ipcp, sp);
        sppp_cp_fini(&pap, sp);
        sppp_cp_fini(&chap, sp);
#ifdef INET6
        sppp_cp_fini(&ipv6cp, sp);
#endif
        sppp_wq_destroy(sp, sp->wq_cp);

        /* free authentication info */
        if (sp->myauth.name) free(sp->myauth.name, M_DEVBUF);
        if (sp->myauth.secret) free(sp->myauth.secret, M_DEVBUF);
        if (sp->hisauth.name) free(sp->hisauth.name, M_DEVBUF);
        if (sp->hisauth.secret) free(sp->hisauth.secret, M_DEVBUF);

        IFQ_LOCK_DESTROY(&sp->pp_fastq);
        rw_destroy(&sp->pp_lock);
}

/*
 * Flush the interface output queue.
 */
void
sppp_flush(struct ifnet *ifp)
{
        struct sppp *sp = (struct sppp *) ifp;

        SPPP_LOCK(sp, RW_WRITER);
        IFQ_PURGE(&sp->pp_if.if_snd);
        IF_PURGE(&sp->pp_fastq);
        IF_PURGE(&sp->pp_cpq);
        SPPP_UNLOCK(sp);
}

/*
 * Check if the output queue is empty.
 */
int
sppp_isempty(struct ifnet *ifp)
{
        struct sppp *sp = (struct sppp *) ifp;
        int empty;

        SPPP_LOCK(sp, RW_READER);
        empty = IF_IS_EMPTY(&sp->pp_fastq) && IF_IS_EMPTY(&sp->pp_cpq) &&
                IFQ_IS_EMPTY(&sp->pp_if.if_snd);
        SPPP_UNLOCK(sp);
        return (empty);
}

/*
 * Get next packet to send.
 */
struct mbuf *
sppp_dequeue(struct ifnet *ifp)
{
        struct sppp *sp = (struct sppp *) ifp;
        struct mbuf *m;

        SPPP_LOCK(sp, RW_WRITER);
        /*
         * Process only the control protocol queue until we have at
         * least one NCP opened.
         */
        IF_DEQUEUE(&sp->pp_cpq, m);
        if (m == NULL && sppp_is_ncp_opened(sp)) {
                IF_DEQUEUE(&sp->pp_fastq, m);
                if (m == NULL)
                        IFQ_DEQUEUE(&sp->pp_if.if_snd, m);
        }
        SPPP_UNLOCK(sp);
        return m;
}

void
sppp_abort_connect(struct ifnet *ifp)
{
        struct sppp *sp = (struct sppp *)ifp;

        SPPP_LOCK(sp, RW_WRITER);
        if (sp->pp_ondemand) {
                if (sp->pp_connecting)
                        sppp_disconnect(sp);
        } else {
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_close);
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_open);
        }
        SPPP_UNLOCK(sp);
}

/*
 * Process an ioctl request.  Called on low priority level.
 */
int
sppp_ioctl(struct ifnet *ifp, u_long cmd, void *data)
{
        struct lwp *l = curlwp; /* XXX */
        struct ifreq *ifr = (struct ifreq *) data;
        struct ifaddr *ifa = (struct ifaddr *) data;
        struct sppp *sp = (struct sppp *) ifp;
        int error=0, going_up, going_down;
        u_long lcp_mru;

        switch (cmd) {
        case SIOCINITIFADDR:
                ifa->ifa_rtrequest = p2p_rtrequest;
                break;

        case SIOCSIFFLAGS:
                if ((error = ifioctl_common(ifp, cmd, data)) != 0)
                        break;

                SPPP_LOCK(sp, RW_WRITER);
                going_up =
                     (ifp->if_flags & IFF_UP) && !sp->pp_connecting;
                going_down =
                     ((ifp->if_flags & IFF_UP) == 0) && sp->pp_connecting;
                if ((ifp->if_flags & IFF_AUTO) &&
                    (ifp->if_flags & IFF_PASSIVE)) {
                        ifp->if_flags &= ~IFF_AUTO;
                }

                atomic_store_relaxed(&sp->pp_ondemand,
                    (ifp->if_flags & IFF_AUTO) ? true : false);

                if (going_up || going_down) {
                        sppp_disconnect(sp);
                }
                if (going_up) {
                        /* Always-on connection */
                        if (!sp->pp_ondemand)
                                sppp_connect(sp);
                } else if (going_down) {
                        SPPP_UNLOCK(sp);
                        sppp_flush(ifp);
                        SPPP_LOCK(sp, RW_WRITER);
                }
                SPPP_UNLOCK(sp);
                break;

        case SIOCSIFMTU:
                if (ifr->ifr_mtu < PPP_MINMRU ||
                    ifr->ifr_mtu > PP_MTU) {
                        error = EINVAL;
                        break;
                }

                error = ifioctl_common(ifp, cmd, data);
                if (error == ENETRESET)
                        error = 0;

                SPPP_LOCK(sp, RW_WRITER);
                lcp_mru = sp->lcp.mru;
                if (ifp->if_mtu < PP_MTU) {
                        sp->lcp.mru = ifp->if_mtu;
                } else {
                        sp->lcp.mru = PP_MTU;
                }
                if (lcp_mru != sp->lcp.mru)
                        SET(sp->lcp.opts, SPPP_LCP_OPT_MRU);

                if (sp->scp[IDX_LCP].state == STATE_OPENED &&
                    ifp->if_mtu > sp->lcp.their_mru) {
                        sp->pp_saved_mtu = ifp->if_mtu;
                        ifp->if_mtu = sp->lcp.their_mru;

                        SPPP_DLOG(sp, "setting MTU "
                            "from %"PRIu64" bytes to %"PRIu64" bytes\n",
                            sp->pp_saved_mtu, ifp->if_mtu);
                }
                SPPP_UNLOCK(sp);
                break;

        case SIOCGIFMTU:
                if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
                        error = 0;
                break;
        case SIOCADDMULTI:
        case SIOCDELMULTI:
                break;

        case SPPPSETAUTHCFG:
        case SPPPSETLCPCFG:
        case SPPPSETNCPCFG:
        case SPPPSETIDLETO:
        case SPPPSETAUTHFAILURE:
        case SPPPSETDNSOPTS:
        case SPPPSETKEEPALIVE:
#if defined(COMPAT_50) || defined(MODULAR)
        case __SPPPSETIDLETO50:
        case __SPPPSETKEEPALIVE50:
#endif /* COMPAT_50 || MODULAR */
                error = kauth_authorize_network(l->l_cred,
                    KAUTH_NETWORK_INTERFACE,
                    KAUTH_REQ_NETWORK_INTERFACE_SETPRIV, ifp, (void *)cmd,
                    NULL);
                if (error)
                        break;
                error = sppp_params(sp, cmd, data);
                break;

        case SPPPGETAUTHCFG:
        case SPPPGETLCPCFG:
        case SPPPGETNCPCFG:
        case SPPPGETAUTHFAILURES:
                error = kauth_authorize_network(l->l_cred,
                    KAUTH_NETWORK_INTERFACE,
                    KAUTH_REQ_NETWORK_INTERFACE_GETPRIV, ifp, (void *)cmd,
                    NULL);
                if (error)
                        break;
                error = sppp_params(sp, cmd, data);
                break;

        case SPPPGETSTATUS:
        case SPPPGETSTATUSNCP:
        case SPPPGETIDLETO:
        case SPPPGETDNSOPTS:
        case SPPPGETDNSADDRS:
        case SPPPGETKEEPALIVE:
#if defined(COMPAT_50) || defined(MODULAR)
        case __SPPPGETIDLETO50:
        case __SPPPGETKEEPALIVE50:
#endif /* COMPAT_50 || MODULAR */
        case SPPPGETLCPSTATUS:
        case SPPPGETIPCPSTATUS:
        case SPPPGETIPV6CPSTATUS:
                error = sppp_params(sp, cmd, data);
                break;

        default:
                error = ifioctl_common(ifp, cmd, data);
                break;
        }
        return (error);
}

/*
 * PPP protocol implementation.
 */

/*
 * Send PPP control protocol packet.
 */
static void
sppp_cp_send(struct sppp *sp, u_short proto, u_char type,
             u_char ident, u_short len, void *data)
{
        struct ifnet *ifp = &sp->pp_if;
        struct lcp_header *lh;
        struct mbuf *m;
        size_t pkthdrlen;

        KASSERT(SPPP_WLOCKED(sp));

        pkthdrlen = ISSET(sp->pp_dev_flags, PP_DEVF_NOFRAMING) ?
             2 : PPP_HEADER_LEN;

        if (len > MHLEN - pkthdrlen - LCP_HEADER_LEN)
                len = MHLEN - pkthdrlen - LCP_HEADER_LEN;
        MGETHDR(m, M_DONTWAIT, MT_DATA);
        if (! m) {
                return;
        }
        m->m_pkthdr.len = m->m_len = pkthdrlen + LCP_HEADER_LEN + len;
        m_reset_rcvif(m);

        if (ISSET(sp->pp_dev_flags, PP_DEVF_NOFRAMING)) {
                *mtod(m, uint16_t *) = htons(proto);
                lh = (struct lcp_header *)(mtod(m, uint8_t *) + 2);
        } else {
                struct ppp_header *h;
                h = mtod(m, struct ppp_header *);
                h->address = PPP_ALLSTATIONS;        /* broadcast address */
                h->control = PPP_UI;                 /* Unnumbered Info */
                h->protocol = htons(proto);         /* Link Control Protocol */
                lh = (struct lcp_header *)(h + 1);
        }
        lh->type = type;
        lh->ident = ident;
        lh->len = htons(LCP_HEADER_LEN + len);
        if (len)
                memcpy(lh + 1, data, len);

        if (sppp_debug_enabled(sp)) {
                char pbuf[SPPP_PROTO_NAMELEN];
                char tbuf[SPPP_CPTYPE_NAMELEN];
                const char *pname, *cpname;

                pname = sppp_proto_name(pbuf, sizeof(pbuf), proto);
                cpname = sppp_cp_type_name(tbuf, sizeof(tbuf), lh->type);
                SPPP_LOG(sp, LOG_DEBUG, "%s output <%s id=0x%x len=%d",
                    pname, cpname, lh->ident, ntohs(lh->len));
                if (len)
                        sppp_print_bytes((u_char *)(lh + 1), len);
                addlog(">\n");
        }
        if (IF_QFULL(&sp->pp_cpq)) {
                IF_DROP(&sp->pp_fastq);
                IF_DROP(&ifp->if_snd);
                m_freem(m);
                return;
        }

        if_statadd(ifp, if_obytes, m->m_pkthdr.len + sp->pp_framebytes);
        IF_ENQUEUE(&sp->pp_cpq, m);

        if (! (ifp->if_flags & IFF_OACTIVE)) {
                SPPP_UNLOCK(sp);
                if_start_lock(ifp);
                SPPP_LOCK(sp, RW_WRITER);
        }
}

static void
sppp_cp_to_lcp(void *xsp)
{
        struct sppp *sp = xsp;

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_to);
}

static void
sppp_cp_to_ipcp(void *xsp)
{
        struct sppp *sp = xsp;

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_IPCP].work_to);
}

static void
sppp_cp_to_ipv6cp(void *xsp)
{
        struct sppp *sp = xsp;

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_IPV6CP].work_to);
}

static void
sppp_cp_to_pap(void *xsp)
{
        struct sppp *sp = xsp;

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_PAP].work_to);
}

static void
sppp_cp_to_chap(void *xsp)
{
        struct sppp *sp = xsp;

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_CHAP].work_to);
}

static void
sppp_cp_init(const struct cp *cp, struct sppp *sp)
{
        struct sppp_cp *scp;
        typedef void (*sppp_co_cb_t)(void *);
        static const sppp_co_cb_t to_cb[IDX_COUNT] = {
                [IDX_LCP] = sppp_cp_to_lcp,
                [IDX_IPCP] = sppp_cp_to_ipcp,
                [IDX_IPV6CP] = sppp_cp_to_ipv6cp,
                [IDX_PAP] = sppp_cp_to_pap,
                [IDX_CHAP] = sppp_cp_to_chap,
        };

        scp = &sp->scp[cp->protoidx];
        scp->state = STATE_INITIAL;
        scp->fail_counter = 0;
        scp->seq = 0;
        scp->rseq = 0;

        SPPP_WQ_SET(&scp->work_up, cp->Up, cp);
        SPPP_WQ_SET(&scp->work_down, cp->Down,  cp);
        SPPP_WQ_SET(&scp->work_open, cp->Open, cp);
        SPPP_WQ_SET(&scp->work_close, cp->Close, cp);
        SPPP_WQ_SET(&scp->work_to, cp->TO, cp);
        SPPP_WQ_SET(&scp->work_rcr, sppp_rcr_event, cp);
        SPPP_WQ_SET(&scp->work_rca, sppp_rca_event, cp);
        SPPP_WQ_SET(&scp->work_rcn, sppp_rcn_event, cp);
        SPPP_WQ_SET(&scp->work_rtr, sppp_rtr_event, cp);
        SPPP_WQ_SET(&scp->work_rta, sppp_rta_event, cp);
        SPPP_WQ_SET(&scp->work_rxj, sppp_rxj_event, cp);

        callout_init(&scp->ch, CALLOUT_MPSAFE);
        callout_setfunc(&scp->ch, to_cb[cp->protoidx], sp);
}

static void
sppp_cp_fini(const struct cp *cp, struct sppp *sp)
{
        struct sppp_cp *scp;
        scp = &sp->scp[cp->protoidx];

        sppp_wq_wait(sp->wq_cp, &scp->work_up);
        sppp_wq_wait(sp->wq_cp, &scp->work_down);
        sppp_wq_wait(sp->wq_cp, &scp->work_open);
        sppp_wq_wait(sp->wq_cp, &scp->work_close);
        sppp_wq_wait(sp->wq_cp, &scp->work_to);
        sppp_wq_wait(sp->wq_cp, &scp->work_rcr);
        sppp_wq_wait(sp->wq_cp, &scp->work_rca);
        sppp_wq_wait(sp->wq_cp, &scp->work_rcn);
        sppp_wq_wait(sp->wq_cp, &scp->work_rtr);
        sppp_wq_wait(sp->wq_cp, &scp->work_rta);
        sppp_wq_wait(sp->wq_cp, &scp->work_rxj);

        callout_halt(&scp->ch, NULL);
        callout_destroy(&scp->ch);

        m_freem(scp->mbuf_confreq);
        scp->mbuf_confreq = NULL;
        m_freem(scp->mbuf_confnak);
        scp->mbuf_confnak = NULL;
}

/*
 * Handle incoming PPP control protocol packets.
 */
static void
sppp_cp_input(const struct cp *cp, struct sppp *sp, struct mbuf *m)
{
        const bool debug = sppp_debug_enabled(sp);
        struct ifnet *ifp = &sp->pp_if;
        struct sppp_cp *scp = &sp->scp[cp->protoidx];
        struct lcp_header *h;
        int printlen, len = m->m_pkthdr.len;
        u_char *p;
        uint32_t u32;
        char tbuf[SPPP_CPTYPE_NAMELEN];
        const char *cpname;

        KASSERT(SPPP_WLOCKED(sp));

        if (len < 4) {
                SPPP_DLOG(sp, "%s invalid packet length: %d bytes\n",
                    cp->name, len);
                goto out;
        }
        h = mtod(m, struct lcp_header *);
        if (debug) {
                printlen = ntohs(h->len);
                cpname = sppp_cp_type_name(tbuf, sizeof(tbuf), h->type);
                SPPP_LOG(sp, LOG_DEBUG, "%s input(%s): <%s id=0x%x len=%d",
                    cp->name, sppp_state_name(scp->state),
                    cpname, h->ident, printlen);
                if (len < printlen)
                        printlen = len;
                if (printlen > 4)
                        sppp_print_bytes((u_char *)(h + 1), printlen - 4);
                addlog(">\n");
        }
        if (len > ntohs(h->len))
                len = ntohs(h->len);
        p = (u_char *)(h + 1);
        switch (h->type) {
        case CONF_REQ:
                if (len < 4) {
                        SPPP_DLOG(sp,"%s invalid conf-req length %d\n",
                            cp->name, len);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                scp->rcr_type = CP_RCR_NONE;
                scp->rconfid = h->ident;
                m_freem(scp->mbuf_confreq);
                scp->mbuf_confreq = m;
                m = NULL;
                sppp_wq_add(sp->wq_cp, &scp->work_rcr);
                break;
        case CONF_ACK:
                if (h->ident != scp->confid) {
                        SPPP_DLOG(sp, "%s id mismatch 0x%x != 0x%x\n",
                            cp->name, h->ident, scp->confid);
                        if_statinc(ifp, if_ierrors);
                        break;
                }
                sppp_wq_add(sp->wq_cp, &scp->work_rca);
                break;
        case CONF_NAK:
        case CONF_REJ:
                if (h->ident != scp->confid) {
                        SPPP_DLOG(sp, "%s id mismatch 0x%x != 0x%x\n",
                            cp->name, h->ident, scp->confid);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                m_freem(scp->mbuf_confnak);
                scp->mbuf_confnak = m;
                m = NULL;
                sppp_wq_add(sp->wq_cp, &scp->work_rcn);
                break;
        case TERM_REQ:
                scp->rseq = h->ident;
                sppp_wq_add(sp->wq_cp, &scp->work_rtr);
                break;
        case TERM_ACK:
                if (h->ident != scp->confid &&
                    h->ident != scp->seq) {
                        SPPP_DLOG(sp, "%s id mismatch "
                            "0x%x != 0x%x and 0x%x != %0lx\n",
                            cp->name, h->ident, scp->confid,
                            h->ident, scp->seq);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                sppp_wq_add(sp->wq_cp, &scp->work_rta);
                break;
        case CODE_REJ:
                /* XXX catastrophic rejects (RXJ-) aren't handled yet. */
                cpname = sppp_cp_type_name(tbuf, sizeof(tbuf), h->type);
                SPPP_LOG(sp, LOG_INFO, "%s: ignoring RXJ (%s) for code ?, "
                    "danger will robinson\n", cp->name, cpname);
                sppp_wq_add(sp->wq_cp, &scp->work_rxj);
                break;
        case PROTO_REJ:
            {
                int catastrophic;
                const struct cp *upper;
                int i;
                uint16_t proto;

                catastrophic = 0;
                upper = NULL;
                proto = p[0] << 8 | p[1];
                for (i = 0; i < IDX_COUNT; i++) {
                        if (cps[i]->proto == proto) {
                                upper = cps[i];
                                break;
                        }
                }
                if (upper == NULL)
                        catastrophic++;

                if (debug) {
                        cpname = sppp_cp_type_name(tbuf, sizeof(tbuf), h->type);
                        SPPP_LOG(sp, LOG_INFO,
                            "%s: RXJ%c (%s) for proto 0x%x (%s/%s)\n",
                            cp->name, catastrophic ? '-' : '+',
                            cpname, proto, upper ? upper->name : "unknown",
                            upper ? sppp_state_name(sp->scp[upper->protoidx].state) : "?");
                }

                /*
                 * if we got RXJ+ against conf-req, the peer does not implement
                 * this particular protocol type.  terminate the protocol.
                 */
                if (upper && !catastrophic) {
                        if (sp->scp[upper->protoidx].state == STATE_REQ_SENT) {
                                sppp_wq_add(sp->wq_cp,
                                    &sp->scp[upper->protoidx].work_close);
                                break;
                        }
                }
                sppp_wq_add(sp->wq_cp, &scp->work_rxj);
                break;
            }
        case DISC_REQ:
                if (cp->proto != PPP_LCP)
                        goto illegal;
                /* Discard the packet. */
                break;
        case ECHO_REQ:
                if (cp->proto != PPP_LCP)
                        goto illegal;
                if (scp->state != STATE_OPENED) {
                        SPPP_DLOG(sp, "lcp echo req but lcp closed\n");
                        if_statinc(ifp, if_ierrors);
                        break;
                }
                if (len < 8) {
                        SPPP_DLOG(sp, "invalid lcp echo request "
                               "packet length: %d bytes\n", len);
                        break;
                }
                memcpy(&u32, h + 1, sizeof u32);
                if (ntohl(u32) == sp->lcp.magic) {
                        /* Line loopback mode detected. */
                        SPPP_DLOG(sp, "loopback\n");

                        /* Shut down the PPP link. */
                        if (sp->pp_flags & PP_IFDOWN)
                                sppp_wq_add(sp->wq_cp, &sp->work_ifdown);

                        /* Reset the PPP link. */
                        sppp_wq_add(sp->wq_cp,
                            &sp->scp[IDX_LCP].work_close);
                        sppp_wq_add(sp->wq_cp,
                            &sp->scp[IDX_LCP].work_open);
                        break;
                }
                u32 = htonl(sp->lcp.magic);
                memcpy(h + 1, &u32, sizeof u32);
                SPPP_DLOG(sp, "got lcp echo req, sending echo rep\n");
                sppp_cp_send(sp, PPP_LCP, ECHO_REPLY, h->ident, len - 4,
                    h + 1);
                break;
        case ECHO_REPLY:
                if (cp->proto != PPP_LCP)
                        goto illegal;
                if (h->ident != sp->lcp.echoid) {
                        if_statinc(ifp, if_ierrors);
                        break;
                }
                if (len < 8) {
                        SPPP_DLOG(sp, "lcp invalid echo reply "
                            "packet length: %d bytes\n", len);
                        break;
                }
                SPPP_DLOG(sp, "lcp got echo rep\n");
                memcpy(&u32, h + 1, sizeof u32);
                if (ntohl(u32) != sp->lcp.magic)
                        sp->pp_alivecnt = 0;
                break;
        default:
                /* Unknown packet type -- send Code-Reject packet. */
          illegal:
                SPPP_DLOG(sp, "%s send code-rej for 0x%x\n",
                    cp->name, h->type);
                sppp_cp_send(sp, cp->proto, CODE_REJ,
                    ++scp->seq, m->m_pkthdr.len, h);
                if_statinc(ifp, if_ierrors);
        }

out:
        m_freem(m);
}

/*
 * The generic part of all Up/Down/Open/Close/TO event handlers.
 * Basically, the state transition handling in the automaton.
 */
static void
sppp_up_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        if ((cp->flags & CP_AUTH) != 0 &&
            sppp_auth_role(cp, sp) == SPPP_AUTH_NOROLE)
                return;

        SPPP_DLOG(sp, "%s up(%s)\n", cp->name,
            sppp_state_name(sp->scp[cp->protoidx].state));

        switch (sp->scp[cp->protoidx].state) {
        case STATE_INITIAL:
                sppp_cp_change_state(cp, sp, STATE_CLOSED);
                break;
        case STATE_STARTING:
                sp->scp[cp->protoidx].rst_counter = sp->lcp.max_configure;
                (cp->scr)(sp);
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                break;
        default:
                SPPP_LOG(sp, LOG_DEBUG,
                    "%s illegal up in state %s\n", cp->name,
                    sppp_state_name(sp->scp[cp->protoidx].state));
        }
}

static void
sppp_down_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        if ((cp->flags & CP_AUTH) != 0 &&
            sppp_auth_role(cp, sp) == SPPP_AUTH_NOROLE)
                return;

        SPPP_DLOG(sp, "%s down(%s)\n", cp->name,
            sppp_state_name(sp->scp[cp->protoidx].state));

        switch (sp->scp[cp->protoidx].state) {
        case STATE_CLOSED:
        case STATE_CLOSING:
                sppp_cp_change_state(cp, sp, STATE_INITIAL);
                break;
        case STATE_STOPPED:
                (cp->tls)(cp, sp);
                /* fall through */
        case STATE_STOPPING:
        case STATE_REQ_SENT:
        case STATE_ACK_RCVD:
        case STATE_ACK_SENT:
                sppp_cp_change_state(cp, sp, STATE_STARTING);
                break;
        case STATE_OPENED:
                (cp->tld)(sp);
                sppp_cp_change_state(cp, sp, STATE_STARTING);
                break;
        default:
                /*
                 * a down event may be caused regardless
                 * of state just in LCP case.
                 */
                if (cp->proto == PPP_LCP)
                        break;

                SPPP_LOG(sp, LOG_DEBUG,
                    "%s illegal down in state %s\n", cp->name,
                    sppp_state_name(sp->scp[cp->protoidx].state));
        }
}

static void
sppp_open_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        if ((cp->flags & CP_AUTH) != 0 &&
            sppp_auth_role(cp, sp) == SPPP_AUTH_NOROLE)
                return;

        SPPP_DLOG(sp, "%s open(%s)\n", cp->name,
            sppp_state_name(sp->scp[cp->protoidx].state));

        switch (sp->scp[cp->protoidx].state) {
        case STATE_INITIAL:
                sppp_cp_change_state(cp, sp, STATE_STARTING);
                (cp->tls)(cp, sp);
                break;
        case STATE_STARTING:
                break;
        case STATE_CLOSED:
                sp->scp[cp->protoidx].rst_counter = sp->lcp.max_configure;
                sp->lcp.protos |= (1 << cp->protoidx);
                (cp->scr)(sp);
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                break;
        case STATE_STOPPED:
        case STATE_STOPPING:
        case STATE_REQ_SENT:
        case STATE_ACK_RCVD:
        case STATE_ACK_SENT:
        case STATE_OPENED:
                break;
        case STATE_CLOSING:
                sppp_cp_change_state(cp, sp, STATE_STOPPING);
                break;
        }
}

static void
sppp_close_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        if ((cp->flags & CP_AUTH) != 0 &&
            sppp_auth_role(cp, sp) == SPPP_AUTH_NOROLE)
                return;

        SPPP_DLOG(sp, "%s close(%s)\n", cp->name,
            sppp_state_name(sp->scp[cp->protoidx].state));

        switch (sp->scp[cp->protoidx].state) {
        case STATE_INITIAL:
        case STATE_CLOSED:
        case STATE_CLOSING:
                break;
        case STATE_STARTING:
                sppp_cp_change_state(cp, sp, STATE_INITIAL);
                (cp->tlf)(cp, sp);
                break;
        case STATE_STOPPED:
                sppp_cp_change_state(cp, sp, STATE_CLOSED);
                break;
        case STATE_STOPPING:
                sppp_cp_change_state(cp, sp, STATE_CLOSING);
                break;
        case STATE_OPENED:
                (cp->tld)(sp);
                /* fall through */
        case STATE_REQ_SENT:
        case STATE_ACK_RCVD:
        case STATE_ACK_SENT:
                sp->scp[cp->protoidx].rst_counter = sp->lcp.max_terminate;
                if ((cp->flags & CP_AUTH) == 0) {
                        sppp_cp_send(sp, cp->proto, TERM_REQ,
                            ++sp->scp[cp->protoidx].seq, 0, 0);
                }
                sppp_cp_change_state(cp, sp, STATE_CLOSING);
                break;
        }
}

static void
sppp_to_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        SPPP_DLOG(sp, "%s TO(%s) rst_counter = %d\n", cp->name,
            sppp_state_name(sp->scp[cp->protoidx].state),
            sp->scp[cp->protoidx].rst_counter);

        if (--sp->scp[cp->protoidx].rst_counter < 0)
                /* TO- event */
                switch (sp->scp[cp->protoidx].state) {
                case STATE_CLOSING:
                        sppp_cp_change_state(cp, sp, STATE_CLOSED);
                        (cp->tlf)(cp, sp);
                        break;
                case STATE_STOPPING:
                        sppp_cp_change_state(cp, sp, STATE_STOPPED);
                        (cp->tlf)(cp, sp);
                        break;
                case STATE_REQ_SENT:
                case STATE_ACK_RCVD:
                case STATE_ACK_SENT:
                        sppp_cp_change_state(cp, sp, STATE_STOPPED);
                        (cp->tlf)(cp, sp);
                        break;
                }
        else
                /* TO+ event */
                switch (sp->scp[cp->protoidx].state) {
                case STATE_CLOSING:
                case STATE_STOPPING:
                        if ((cp->flags & CP_AUTH) == 0) {
                                sppp_cp_send(sp, cp->proto, TERM_REQ,
                                    ++sp->scp[cp->protoidx].seq, 0, 0);
                        }
                        callout_schedule(&sp->scp[cp->protoidx].ch, sp->lcp.timeout);
                        break;
                case STATE_REQ_SENT:
                case STATE_ACK_RCVD:
                        (cp->scr)(sp);
                        /* sppp_cp_change_state() will restart the timer */
                        sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                        break;
                case STATE_ACK_SENT:
                        (cp->scr)(sp);
                        callout_schedule(&sp->scp[cp->protoidx].ch, sp->lcp.timeout);
                        break;
                }
}
static void
sppp_rcr_update_state(const struct cp *cp, struct sppp *sp,
    enum cp_rcr_type type, uint8_t ident, size_t msglen, void *msg)
{
        struct ifnet *ifp = &sp->pp_if;
        u_char ctype;

        if (type == CP_RCR_ERR) {
                /* parse error, shut down */
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_close);
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_open);
        } else if (type == CP_RCR_ACK) {
                /* RCR+ event */
                ctype = CONF_ACK;
                switch (sp->scp[cp->protoidx].state) {
                case STATE_OPENED:
                        sppp_cp_change_state(cp, sp, STATE_ACK_SENT);
                        cp->tld(sp);
                        cp->scr(sp);
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_REQ_SENT:
                        sppp_cp_change_state(cp, sp, STATE_ACK_SENT);
                        /* fall through */
                case STATE_ACK_SENT:
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_STOPPED:
                        sppp_cp_change_state(cp, sp, STATE_ACK_SENT);
                        cp->scr(sp);
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_ACK_RCVD:
                        sppp_cp_change_state(cp, sp, STATE_OPENED);
                        SPPP_DLOG(sp, "%s tlu\n", cp->name);
                        cp->tlu(sp);
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_CLOSING:
                case STATE_STOPPING:
                        break;
                case STATE_CLOSED:
                        if ((cp->flags & CP_AUTH) == 0) {
                                sppp_cp_send(sp, cp->proto, TERM_ACK,
                                    ident, 0, 0);
                        }
                        break;
                default:
                        SPPP_LOG(sp, LOG_DEBUG,
                            "%s illegal RCR+ in state %s\n", cp->name,
                            sppp_state_name(sp->scp[cp->protoidx].state));
                        if_statinc(ifp, if_ierrors);
                }
        } else if (type == CP_RCR_NAK || type == CP_RCR_REJ) {
                ctype = type == CP_RCR_NAK ? CONF_NAK : CONF_REJ;
                /* RCR- event */
                switch (sp->scp[cp->protoidx].state) {
                case STATE_OPENED:
                        sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                        cp->tld(sp);
                        cp->scr(sp);
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_ACK_SENT:
                        sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                        /* fall through */
                case STATE_REQ_SENT:
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_STOPPED:
                        sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                        cp->scr(sp);
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_ACK_RCVD:
                        sppp_cp_change_state(cp, sp, STATE_ACK_RCVD);
                        cp->screply(cp, sp, ctype, ident, msglen, msg);
                        break;
                case STATE_CLOSING:
                case STATE_STOPPING:
                        break;
                case STATE_CLOSED:
                        sppp_cp_change_state(cp, sp, STATE_CLOSED);
                        if ((cp->flags & CP_AUTH) == 0) {
                                sppp_cp_send(sp, cp->proto, TERM_ACK,
                                    ident, 0, 0);
                        }
                        break;
                default:
                        SPPP_LOG(sp, LOG_DEBUG,
                            "%s illegal RCR- in state %s\n", cp->name,
                            sppp_state_name(sp->scp[cp->protoidx].state));
                        if_statinc(ifp, if_ierrors);
                }
        }
}

static void
sppp_rcr_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;
        struct sppp_cp *scp;
        struct lcp_header *h;
        struct mbuf *m;
        enum cp_rcr_type type;
        size_t len;
        uint8_t *buf;
        size_t blen, rlen;
        uint8_t ident;

        KASSERT(!cpu_softintr_p());

        scp = &sp->scp[cp->protoidx];

        if (cp->parse_confreq != NULL) {
                m = scp->mbuf_confreq;
                if (m == NULL)
                        return;
                scp->mbuf_confreq = NULL;

                h = mtod(m, struct lcp_header *);
                if (h->type != CONF_REQ) {
                        m_freem(m);
                        return;
                }

                ident = h->ident;
                len = MIN(m->m_pkthdr.len, ntohs(h->len));

                type = (cp->parse_confreq)(sp, h, len,
                    &buf, &blen, &rlen);
                m_freem(m);
        } else {
                /* mbuf_cofreq is already parsed and freed */
                type = scp->rcr_type;
                ident = scp->rconfid;
                buf = NULL;
                blen = rlen = 0;
        }

        sppp_rcr_update_state(cp, sp, type, ident, rlen, (void *)buf);

        if (buf != NULL)
                kmem_free(buf, blen);
}

static void
sppp_rca_event(struct sppp *sp, void *xcp)
{
        struct ifnet *ifp = &sp->pp_if;
        const struct cp *cp = xcp;

        KASSERT(!cpu_softintr_p());

        switch (sp->scp[cp->protoidx].state) {
        case STATE_CLOSED:
        case STATE_STOPPED:
                if ((cp->flags & CP_AUTH) == 0) {
                        sppp_cp_send(sp, cp->proto, TERM_ACK,
                            sp->scp[cp->protoidx].rconfid, 0, 0);
                }
                break;
        case STATE_CLOSING:
        case STATE_STOPPING:
                break;
        case STATE_REQ_SENT:
                sp->scp[cp->protoidx].rst_counter = sp->lcp.max_configure;
                sppp_cp_change_state(cp, sp, STATE_ACK_RCVD);
                break;
        case STATE_OPENED:
                (cp->tld)(sp);
                /* fall through */
        case STATE_ACK_RCVD:
                (cp->scr)(sp);
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                break;
        case STATE_ACK_SENT:
                sppp_cp_change_state(cp, sp, STATE_OPENED);
                sp->scp[cp->protoidx].rst_counter = sp->lcp.max_configure;
                SPPP_DLOG(sp, "%s tlu\n", cp->name);
                (cp->tlu)(sp);
                break;
        default:
                SPPP_LOG(sp, LOG_DEBUG,
                    "%s illegal RCA in state %s\n", cp->name,
                    sppp_state_name(sp->scp[cp->protoidx].state));
                if_statinc(ifp, if_ierrors);
        }
}

static void
sppp_rcn_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;
        struct sppp_cp *scp;
        struct lcp_header *h;
        struct mbuf *m;
        struct ifnet *ifp = &sp->pp_if;
        size_t len;

        KASSERT(!cpu_softintr_p());

        scp = &sp->scp[cp->protoidx];
        m = scp->mbuf_confnak;
        if (m == NULL)
                return;
        scp->mbuf_confnak = NULL;

        h = mtod(m, struct lcp_header *);
        len = MIN(m->m_pkthdr.len, ntohs(h->len));

        switch (h->type) {
        case CONF_NAK:
                (cp->parse_confnak)(sp, h, len);
                break;
        case CONF_REJ:
                (cp->parse_confrej)(sp, h, len);
                break;
        default:
                m_freem(m);
                return;
        }

        m_freem(m);

        switch (scp->state) {
        case STATE_CLOSED:
        case STATE_STOPPED:
                if ((cp->flags & CP_AUTH) == 0) {
                        sppp_cp_send(sp, cp->proto, TERM_ACK,
                            scp->rconfid, 0, 0);
                }
                break;
        case STATE_REQ_SENT:
        case STATE_ACK_SENT:
                scp->rst_counter = sp->lcp.max_configure;
                (cp->scr)(sp);
                break;
        case STATE_OPENED:
                (cp->tld)(sp);
                /* fall through */
        case STATE_ACK_RCVD:
                sppp_cp_change_state(cp, sp, STATE_ACK_SENT);
                (cp->scr)(sp);
                break;
        case STATE_CLOSING:
        case STATE_STOPPING:
                break;
        default:
                SPPP_LOG(sp, LOG_DEBUG, "%s illegal RCN in state %s\n",
                    cp->name, sppp_state_name(scp->state));
                if_statinc(ifp, if_ierrors);
        }
}

static void
sppp_rtr_event(struct sppp *sp, void *xcp)
{
        struct ifnet *ifp = &sp->pp_if;
        const struct cp *cp = xcp;

        KASSERT(!cpu_softintr_p());

        switch (sp->scp[cp->protoidx].state) {
        case STATE_ACK_RCVD:
        case STATE_ACK_SENT:
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                break;
        case STATE_CLOSED:
        case STATE_STOPPED:
        case STATE_CLOSING:
        case STATE_STOPPING:
        case STATE_REQ_SENT:
                break;
        case STATE_OPENED:
                (cp->tld)(sp);
                sp->scp[cp->protoidx].rst_counter = 0;
                sppp_cp_change_state(cp, sp, STATE_STOPPING);
                break;
        default:
                SPPP_LOG(sp, LOG_DEBUG, "%s illegal RTR in state %s\n",
                    cp->name,
                    sppp_state_name(sp->scp[cp->protoidx].state));
                if_statinc(ifp, if_ierrors);
                return;
        }

        /* Send Terminate-Ack packet. */
        SPPP_DLOG(sp, "%s send terminate-ack\n", cp->name);
        if ((cp->flags & CP_AUTH) == 0) {
                sppp_cp_send(sp, cp->proto, TERM_ACK,
                    sp->scp[cp->protoidx].rseq, 0, 0);
        }
}

static void
sppp_rta_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;
        struct ifnet *ifp = &sp->pp_if;

        KASSERT(!cpu_softintr_p());

        switch (sp->scp[cp->protoidx].state) {
        case STATE_CLOSED:
        case STATE_STOPPED:
        case STATE_REQ_SENT:
        case STATE_ACK_SENT:
                break;
        case STATE_CLOSING:
                sppp_cp_change_state(cp, sp, STATE_CLOSED);
                (cp->tlf)(cp, sp);
                break;
        case STATE_STOPPING:
                sppp_cp_change_state(cp, sp, STATE_STOPPED);
                (cp->tlf)(cp, sp);
                break;
        case STATE_ACK_RCVD:
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                break;
        case STATE_OPENED:
                (cp->tld)(sp);
                (cp->scr)(sp);
                sppp_cp_change_state(cp, sp, STATE_ACK_RCVD);
                break;
        default:
                SPPP_LOG(sp, LOG_DEBUG, "%s illegal RTA in state %s\n",
                    cp->name,  sppp_state_name(sp->scp[cp->protoidx].state));
                if_statinc(ifp, if_ierrors);
        }
}

static void
sppp_rxj_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;
        struct ifnet *ifp = &sp->pp_if;

        KASSERT(!cpu_softintr_p());

        /* XXX catastrophic rejects (RXJ-) aren't handled yet. */
        switch (sp->scp[cp->protoidx].state) {
        case STATE_CLOSED:
        case STATE_STOPPED:
        case STATE_REQ_SENT:
        case STATE_ACK_SENT:
        case STATE_CLOSING:
        case STATE_STOPPING:
        case STATE_OPENED:
                break;
        case STATE_ACK_RCVD:
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                break;
        default:
                SPPP_LOG(sp, LOG_DEBUG, "%s illegal RXJ- in state %s\n",
                    cp->name,  sppp_state_name(sp->scp[cp->protoidx].state));
                if_statinc(ifp, if_ierrors);
        }
}

/*
 * Change the state of a control protocol in the state automaton.
 * Takes care of starting/stopping the restart timer.
 */
void
sppp_cp_change_state(const struct cp *cp, struct sppp *sp, int newstate)
{

        KASSERT(SPPP_WLOCKED(sp));

        sp->scp[cp->protoidx].state = newstate;
        callout_stop(&sp->scp[cp->protoidx].ch);
        switch (newstate) {
        case STATE_INITIAL:
        case STATE_STARTING:
        case STATE_CLOSED:
        case STATE_STOPPED:
        case STATE_OPENED:
                break;
        case STATE_CLOSING:
        case STATE_STOPPING:
        case STATE_REQ_SENT:
        case STATE_ACK_RCVD:
        case STATE_ACK_SENT:
                callout_schedule(&sp->scp[cp->protoidx].ch, sp->lcp.timeout);
                break;
        }
}

/*
 *--------------------------------------------------------------------------*
 *                                                                          *
 *                         The LCP implementation.                          *
 *                                                                          *
 *--------------------------------------------------------------------------*
 */
static void
sppp_lcp_init(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        sppp_cp_init(&lcp, sp);

        SET(sp->lcp.opts, SPPP_LCP_OPT_MAGIC);
        sp->lcp.magic = 0;
        sp->lcp.protos = 0;
        sp->lcp.max_terminate = 2;
        sp->lcp.max_configure = 10;
        sp->lcp.max_failure = 10;
        sp->lcp.lower_running = false;

        /*
         * Initialize counters and timeout values.  Note that we don't
         * use the 3 seconds suggested in RFC 1661 since we are likely
         * running on a fast link.  XXX We should probably implement
         * the exponential backoff option.  Note that these values are
         * relevant for all control protocols, not just LCP only.
         */
        sp->lcp.timeout = 1 * hz;
}

static void
sppp_lcp_up(struct sppp *sp, void *xcp)
{

        KASSERT(SPPP_WLOCKED(sp));

        /* Initialize activity timestamp: opening a connection is an activity */
        atomic_store_relaxed(&sp->pp_last_receive, time_uptime32);
        atomic_store_relaxed(&sp->pp_last_activity, time_uptime32);

        sppp_up_event(sp, xcp);
}

static void
sppp_lcp_down(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;
        int pidx = cp->protoidx;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        sppp_down_event(sp, xcp);

        switch (sp->scp[pidx].state) {
        case STATE_STARTING:
                /*
                 * Req-Sent/Ack-Sent/Ack-Rcvd -> Starting:
                 * This transition requires an extra TLS action.
                 * * sequence of events/actions:
                 * 1. Closing -> Closed      : Triggers TLF  action.
                 * 2. Closed  -> Req-Sent    : Occurs on Open event.
                 * 3. Req-Sent -> Ack-Sent...: (Optional state progression)
                 * 4. Req-Sent/Ack-Sent/Ack-Rcvd -> Starting:
                 *    - Triggered by a Down event caused by the previous TLF action.
                 *    - This specific transition does NOT trigger another TLS action.
                 */
                cp->tls(cp, sp);
                break;
        case STATE_INITIAL:
                /*
                 * Closing -> Initial:
                 * A Down event in the Closing state triggers a transition to
                 * Initial state without a TLF action. Since the lower layer
                 * will attempt to reconnect, we explicitly stop it here.
                 */
                cp->tlf(cp, sp);
                break;
        }

        SPPP_DLOG(sp, "Down event (carrier loss)\n");

        sp->scp[pidx].fail_counter = 0;
}

static void
sppp_lcp_open(struct sppp *sp, void *xcp)
{

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        sp->scp[IDX_LCP].fail_counter = 0;

        if (sp->pp_if.if_mtu < PP_MTU) {
                sp->lcp.mru = sp->pp_if.if_mtu;
                SET(sp->lcp.opts, SPPP_LCP_OPT_MRU);
        } else {
                sp->lcp.mru = PP_MTU;
        }
        sp->lcp.their_mru = PP_MTU;

        /*
         * If we are authenticator, negotiate LCP_AUTH
         */
        if (sp->hisauth.proto != PPP_NOPROTO)
                SET(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO);
        else
                CLR(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO);
        sp->pp_flags &= ~PP_NEEDAUTH;
        sppp_open_event(sp, xcp);
}

/*
 * Analyze a configure request.  Return true if it was agreeable, and
 * caused action sca, false if it has been rejected or nak'ed, and
 * caused action scn.  (The return value is used to make the state
 * transition decision in the state automaton.)
 */
static enum cp_rcr_type
sppp_lcp_confreq(struct sppp *sp, struct lcp_header *h, int origlen,
    uint8_t **msgbuf, size_t *buflen, size_t *msglen)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *buf, *r, *p, l, blen;
        enum cp_rcr_type type;
        int len, rlen;
        uint32_t nmagic;
        u_short authproto;
        char lbuf[SPPP_LCPOPT_NAMELEN];

        KASSERT(SPPP_WLOCKED(sp));

        if (origlen < sizeof(*h))
                return CP_RCR_DROP;

        origlen -= sizeof(*h);
        type = CP_RCR_NONE;
        type = 0;

        if (origlen <= 0)
                return CP_RCR_DROP;
        else
                blen = origlen;

        buf = kmem_intr_alloc(blen, KM_NOSLEEP);
        if (buf == NULL)
                return CP_RCR_DROP;

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "lcp parse opts:");

        /* pass 1: check for things that need to be rejected */
        p = (void *)(h + 1);
        r = buf;
        rlen = 0;
        for (len = origlen; len > 1; len-= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                /* Sanity check option length */
                if (l > len) {
                        /*
                         * Malicious option - drop immediately.
                         * XXX Maybe we should just RXJ it?
                         */
                        if (debug)
                                addlog("\n");

                        SPPP_LOG(sp, LOG_DEBUG,
                            "received malicious LCP option 0x%02x, "
                            "length 0x%02x, (len: 0x%02x) dropping.\n",
                            p[0], l, len);
                        type = CP_RCR_ERR;
                        goto end;
                }
                if (debug)
                        addlog(" %s", sppp_lcp_opt_name(lbuf, sizeof(lbuf), *p));
                switch (p[0]) {
                case LCP_OPT_MAGIC:
                        /* Magic number. */
                        /* fall through, both are same length */
                case LCP_OPT_ASYNC_MAP:
                        /* Async control character map. */
                        if (len >= 6 || l == 6)
                                continue;
                        if (debug)
                                addlog(" [invalid]");
                        break;
                case LCP_OPT_MP_EID:
                        if (len >= l && l >= 3) {
                                switch (p[2]) {
                                case 0: if (l==3+ 0) continue;break;
                                case 2: if (l==3+ 4) continue;break;
                                case 3: if (l==3+ 6) continue;break;
                                case 6: if (l==3+16) continue;break;
                                case 1: /* FALLTHROUGH */
                                case 4: if (l<=3+20) continue;break;
                                case 5: if (l<=3+15) continue;break;
                                /* XXX should it be default: continue;? */
                                }
                        }
                        if (debug)
                                addlog(" [invalid class %d len %d]", p[2], l);
                        break;
                case LCP_OPT_MP_SSNHF:
                        if (len >= 2 && l == 2) {
                                if (debug)
                                        addlog(" [rej]");
                                break;
                        }
                        if (debug)
                                addlog(" [invalid]");
                        break;
                case LCP_OPT_MP_MRRU:
                        /* Multilink maximum received reconstructed unit */
                        /* should be fall through, both are same length */
                        /* FALLTHROUGH */
                case LCP_OPT_MRU:
                        /* Maximum receive unit. */
                        if (len >= 4 && l == 4)
                                continue;
                        if (debug)
                                addlog(" [invalid]");
                        break;
                case LCP_OPT_AUTH_PROTO:
                        if (len < 4) {
                                if (debug)
                                        addlog(" [invalid]");
                                break;
                        }
                        authproto = (p[2] << 8) + p[3];
                        if (authproto == PPP_CHAP && l != 5) {
                                if (debug)
                                        addlog(" [invalid chap len]");
                                break;
                        }
                        if (ISSET(sp->myauth.flags, SPPP_AUTHFLAG_PASSIVEAUTHPROTO)) {
                                if (authproto == PPP_PAP || authproto == PPP_CHAP)
                                        sp->myauth.proto = authproto;
                        }
                        if (sp->myauth.proto == PPP_NOPROTO) {
                                /* we are not configured to do auth */
                                if (debug)
                                        addlog(" [not configured]");
                                break;
                        }
                        /*
                         * Remote want us to authenticate, remember this,
                         * so we stay in SPPP_PHASE_AUTHENTICATE after LCP got
                         * up.
                         */
                        sp->pp_flags |= PP_NEEDAUTH;
                        continue;
                default:
                        /* Others not supported. */
                        if (debug)
                                addlog(" [rej]");
                        break;
                }
                if (rlen + l > blen) {
                        if (debug)
                                addlog(" [overflow]");
                        continue;
                }
                /* Add the option to rejected list. */
                memcpy(r, p, l);
                r += l;
                rlen += l;
        }

        if (rlen > 0) {
                type = CP_RCR_REJ;
                goto end;
        }

        if (debug)
                addlog("\n");

        /*
         * pass 2: check for option values that are unacceptable and
         * thus require to be nak'ed.
         */
        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "lcp parse opt values:");

        p = (void *)(h + 1);
        r = buf;
        rlen = 0;
        for (len = origlen; len > 0; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                if (debug)
                        addlog(" %s", sppp_lcp_opt_name(lbuf, sizeof(lbuf), *p));
                switch (p[0]) {
                case LCP_OPT_MAGIC:
                        /* Magic number -- extract. */
                        nmagic = (uint32_t)p[2] << 24 |
                                (uint32_t)p[3] << 16 | p[4] << 8 | p[5];
                        if (nmagic != sp->lcp.magic) {
                                if (debug)
                                        addlog(" 0x%x", nmagic);
                                continue;
                        }
                        /*
                         * Local and remote magics equal -- loopback?
                         */
                        if (sp->pp_loopcnt >= LOOPALIVECNT*5) {
                                SPPP_DLOG(sp, "loopback\n");
                                sp->pp_loopcnt = 0;

                                if (sp->pp_flags & PP_IFDOWN)
                                        sppp_wq_add(sp->wq_cp, &sp->work_ifdown);
                                sppp_wq_add(sp->wq_cp,
                                    &sp->scp[IDX_LCP].work_close);
                                sppp_wq_add(sp->wq_cp,
                                    &sp->scp[IDX_LCP].work_open);
                        } else {
                                if (debug)
                                        addlog(" [glitch]");
                                ++sp->pp_loopcnt;
                        }
                        /*
                         * We negate our magic here, and NAK it.  If
                         * we see it later in an NAK packet, we
                         * suggest a new one.
                         */
                        nmagic = ~sp->lcp.magic;
                        /* Gonna NAK it. */
                        p[2] = nmagic >> 24;
                        p[3] = nmagic >> 16;
                        p[4] = nmagic >> 8;
                        p[5] = nmagic;
                        break;

                case LCP_OPT_ASYNC_MAP:
                        /*
                         * Async control character map -- just ignore it.
                         *
                         * Quote from RFC 1662, chapter 6:
                         * To enable this functionality, synchronous PPP
                         * implementations MUST always respond to the
                         * Async-Control-Character-Map Configuration
                         * Option with the LCP Configure-Ack.  However,
                         * acceptance of the Configuration Option does
                         * not imply that the synchronous implementation
                         * will do any ACCM mapping.  Instead, all such
                         * octet mapping will be performed by the
                         * asynchronous-to-synchronous converter.
                         */
                        continue;

                case LCP_OPT_MRU:
                        /*
                         * Maximum receive unit.  Always agreeable,
                         * but ignored by now.
                         */
                        sp->lcp.their_mru = p[2] * 256 + p[3];
                        if (debug)
                                addlog(" %ld", sp->lcp.their_mru);
                        continue;

                case LCP_OPT_AUTH_PROTO:
                        authproto = (p[2] << 8) + p[3];
                        if (ISSET(sp->myauth.flags, SPPP_AUTHFLAG_PASSIVEAUTHPROTO)) {
                                if (authproto == PPP_PAP || authproto == PPP_CHAP)
                                        sp->myauth.proto = authproto;
                        }
                        if (sp->myauth.proto == authproto) {
                                if (authproto != PPP_CHAP || p[4] == CHAP_MD5) {
                                        continue;
                                }
                                if (debug)
                                        addlog(" [chap without MD5]");
                        } else {
                                if (debug) {
                                        char pbuf1[SPPP_PROTO_NAMELEN];
                                        char pbuf2[SPPP_PROTO_NAMELEN];
                                        const char *pname1, *pname2;

                                        pname1 = sppp_proto_name(pbuf1,
                                            sizeof(pbuf1), sp->myauth.proto);
                                        pname2 = sppp_proto_name(pbuf2,
                                            sizeof(pbuf2), authproto);
                                        addlog(" [mine %s != his %s]",
                                               pname1, pname2);
                                }
                        }
                        /* not agreed, nak */
                        if (sp->myauth.proto == PPP_CHAP) {
                                l = 5;
                        } else {
                                l = 4;
                        }

                        if (rlen + l > blen) {
                                if (debug)
                                        addlog(" [overflow]");
                                continue;
                        }

                        r[0] = LCP_OPT_AUTH_PROTO;
                        r[1] = l;
                        r[2] = sp->myauth.proto >> 8;
                        r[3] = sp->myauth.proto & 0xff;
                        if (sp->myauth.proto == PPP_CHAP)
                                r[4] = CHAP_MD5;
                        rlen += l;
                        r += l;
                        continue;
                case LCP_OPT_MP_EID:
                        /*
                         * Endpoint identification.
                         * Always agreeable,
                         * but ignored by now.
                         */
                        if (debug) {
                                addlog(" type %d", p[2]);
                                sppp_print_bytes(p+3, p[1]-3);
                        }
                        continue;
                case LCP_OPT_MP_MRRU:
                        /*
                         * Maximum received reconstructed unit. 
                         * Always agreeable,
                         * but ignored by now.
                         */
                        sp->lcp.their_mrru = p[2] * 256 + p[3];
                        if (debug)
                                addlog(" %ld", sp->lcp.their_mrru);
                        continue;
                }
                if (rlen + l > blen) {
                        if (debug)
                                addlog(" [overflow]");
                        continue;
                }
                /* Add the option to nak'ed list. */
                memcpy(r, p, l);
                r += l;
                rlen += l;
        }

        if (rlen > 0) {
                if (++sp->scp[IDX_LCP].fail_counter >= sp->lcp.max_failure) {
                        if (debug)
                                addlog(" max_failure (%d) exceeded, ",
                                    sp->lcp.max_failure);
                        type = CP_RCR_REJ;
                } else {
                        type = CP_RCR_NAK;
                }
        } else {
                type = CP_RCR_ACK;
                rlen = origlen;
                memcpy(r, h + 1, rlen);
                sp->scp[IDX_LCP].fail_counter = 0;
                sp->pp_loopcnt = 0;
        }

end:
        if (debug)
                addlog("\n");

        if (type == CP_RCR_ERR || type == CP_RCR_DROP) {
                if (buf != NULL)
                        kmem_intr_free(buf, blen);
        } else {
                *msgbuf = buf;
                *buflen = blen;
                *msglen = rlen;
        }

        return type;
}

/*
 * Analyze the LCP Configure-Reject option list, and adjust our
 * negotiation.
 */
static void
sppp_lcp_confrej(struct sppp *sp, struct lcp_header *h, int len)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *p, l;

        KASSERT(SPPP_WLOCKED(sp));

        if (len <= sizeof(*h))
                return;

        len -= sizeof(*h);

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "lcp rej opts:");

        p = (void *)(h + 1);
        for (; len > 1 && (l = p[1]) != 0; len -= l, p += l) {
                /* Sanity check option length */
                if (l > len) {
                        /*
                         * Malicious option - drop immediately.
                         * XXX Maybe we should just RXJ it?
                         */
                        if (debug)
                                addlog("\n");

                        SPPP_LOG(sp, LOG_DEBUG,
                            "received malicious LCP option, dropping.\n");
                        goto end;
                }
                if (debug) {
                        char lbuf[SPPP_LCPOPT_NAMELEN];
                        addlog(" %s", sppp_lcp_opt_name(lbuf, sizeof(lbuf), *p));
                }
                switch (p[0]) {
                case LCP_OPT_MAGIC:
                        /* Magic number -- can't use it, use 0 */
                        CLR(sp->lcp.opts, SPPP_LCP_OPT_MAGIC);
                        sp->lcp.magic = 0;
                        break;
                case LCP_OPT_MRU:
                        /*
                         * We try to negotiate a lower MRU if the underlying
                         * link's MTU is less than PP_MTU (e.g. PPPoE). If the
                         * peer rejects this lower rate, fallback to the
                         * default.
                         */
                        if (!debug) {
                                SPPP_LOG(sp, LOG_INFO,
                                    "peer rejected our MRU of "
                                    "%ld bytes. Defaulting to %d bytes\n",
                                    sp->lcp.mru, PP_MTU);
                        }
                        CLR(sp->lcp.opts, SPPP_LCP_OPT_MRU);
                        sp->lcp.mru = PP_MTU;
                        break;
                case LCP_OPT_AUTH_PROTO:
                        /*
                         * Peer doesn't want to authenticate himself,
                         * deny unless SPPP_AUTHFLAG_NOCALLOUT is set.
                         */
                        if ((sp->hisauth.flags & SPPP_AUTHFLAG_NOCALLOUT) != 0) {
                                if (debug) {
                                        addlog(" [don't insist on auth "
                                               "for callout]");
                                }
                                CLR(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO);
                                break;
                        }
                        if (debug)
                                addlog("[access denied]\n");
                        sppp_disconnect(sp);
                        break;
                }
        }
        if (debug)
                addlog("\n");
end:
        return;
}

/*
 * Analyze the LCP Configure-NAK option list, and adjust our
 * negotiation.
 */
static void
sppp_lcp_confnak(struct sppp *sp, struct lcp_header *h, int len)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *p, l;
        uint32_t magic;

        KASSERT(SPPP_WLOCKED(sp));

        if (len <= sizeof(*h))
                return;

        len -= sizeof(*h);

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "lcp nak opts:");

        p = (void *)(h + 1);
        for (; len > 1 && (l = p[1]) != 0; len -= l, p += l) {
                /* Sanity check option length */
                if (l > len) {
                        /*
                         * Malicious option - drop immediately.
                         * XXX Maybe we should just RXJ it?
                         */
                        if (debug)
                                addlog("\n");

                        SPPP_LOG(sp, LOG_DEBUG,
                            "received malicious LCP option, dropping.\n");
                        goto end;
                }
                if (debug) {
                        char lbuf[SPPP_LCPOPT_NAMELEN];
                        addlog(" %s", sppp_lcp_opt_name(lbuf, sizeof(lbuf),*p));
                }
                switch (p[0]) {
                case LCP_OPT_MAGIC:
                        /* Magic number -- renegotiate */
                        if (ISSET(sp->lcp.opts, SPPP_LCP_OPT_MAGIC) &&
                            len >= 6 && l == 6) {
                                magic = (uint32_t)p[2] << 24 |
                                        (uint32_t)p[3] << 16 | p[4] << 8 | p[5];
                                /*
                                 * If the remote magic is our negated one,
                                 * this looks like a loopback problem.
                                 * Suggest a new magic to make sure.
                                 */
                                if (magic == ~sp->lcp.magic) {
                                        if (debug)
                                                addlog(" magic glitch");
                                        sp->lcp.magic = cprng_fast32();
                                } else {
                                        sp->lcp.magic = magic;
                                        if (debug)
                                                addlog(" %d", magic);
                                }
                        }
                        break;
                case LCP_OPT_MRU:
                        /*
                         * Peer wants to advise us to negotiate an MRU.
                         * Agree on it if it's reasonable, or use
                         * default otherwise.
                         */
                        if (len >= 4 && l == 4) {
                                u_int mru = p[2] * 256 + p[3];
                                if (debug)
                                        addlog(" %d", mru);
                                if (mru < PPP_MINMRU || mru > sp->pp_if.if_mtu)
                                        mru = sp->pp_if.if_mtu;
                                sp->lcp.mru = mru;
                                SET(sp->lcp.opts, SPPP_LCP_OPT_MRU);
                        }
                        break;
                case LCP_OPT_AUTH_PROTO:
                        /*
                         * Peer doesn't like our authentication method,
                         * deny.
                         */
                        if (debug)
                                addlog("[access denied]\n");
                        sppp_disconnect(sp);
                        break;
                }
        }
        if (debug)
                addlog("\n");
end:
        return;
}

static void
sppp_lcp_tlu(struct sppp *sp)
{
        struct ifnet *ifp = &sp->pp_if;
        struct sppp_cp *scp;
        int i;

        KASSERT(SPPP_WLOCKED(sp));

        /* unlock for IFNET_LOCK */
        SPPP_UNLOCK(sp);

        /* the interface was down by PP_IFDOWN flag */
        if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) == IFF_RUNNING) {
                SPPP_LOG(sp, LOG_DEBUG, "interface is going up\n");
                if_up(ifp);
        }

        IFNET_LOCK(ifp);
        SPPP_LOCK(sp, RW_WRITER);
        if (ifp->if_mtu > sp->lcp.their_mru) {
                sp->pp_saved_mtu = ifp->if_mtu;
                ifp->if_mtu = sp->lcp.their_mru;
                SPPP_DLOG(sp, "setting MTU "
                    "from %"PRIu64" bytes to %"PRIu64" bytes\n",
                    sp->pp_saved_mtu, ifp->if_mtu);
        }
        SPPP_UNLOCK(sp);
        IFNET_UNLOCK(ifp);

        SPPP_LOCK(sp, RW_WRITER);

        if (ISSET(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO) ||
            (sp->pp_flags & PP_NEEDAUTH) != 0)
                sppp_change_phase(sp, SPPP_PHASE_AUTHENTICATE);
        else
                sppp_change_phase(sp, SPPP_PHASE_NETWORK);

        for (i = 0; i < IDX_COUNT; i++) {
                scp = &sp->scp[(cps[i])->protoidx];

                if (((cps[i])->flags & CP_LCP) == 0)
                        sppp_wq_add(sp->wq_cp, &scp->work_up);

                /*
                 * Open all authentication protocols.  This is even required
                 * if we already proceeded to network phase, since it might be
                 * that remote wants us to authenticate, so we might have to
                 * send a PAP request.  Undesired authentication protocols
                 * don't do anything when they get an Open event.
                 */
                if ((cps[i])->flags & CP_AUTH)
                        sppp_wq_add(sp->wq_cp, &scp->work_open);

                /* Open all NCPs. */
                if (sp->pp_phase == SPPP_PHASE_NETWORK &&
                    ((cps[i])->flags & CP_NCP) != 0) {
                        sppp_wq_add(sp->wq_cp, &scp->work_open);
                }
        }
}

static void
sppp_lcp_tld(struct sppp *sp)
{
        struct ifnet *ifp;
        struct sppp_cp *scp;
        int i, phase;

        KASSERT(SPPP_WLOCKED(sp));

        phase = sp->pp_phase;

        sppp_change_phase(sp, SPPP_PHASE_TERMINATE);

        if (sp->pp_saved_mtu > 0) {
                ifp = &sp->pp_if;

                SPPP_UNLOCK(sp);
                IFNET_LOCK(ifp);
                SPPP_LOCK(sp, RW_WRITER);

                SPPP_DLOG(sp, "setting MTU "
                    "from %"PRIu64" bytes to %"PRIu64" bytes\n",
                    ifp->if_mtu, sp->pp_saved_mtu);

                ifp->if_mtu = sp->pp_saved_mtu;
                sp->pp_saved_mtu = 0;
                IFNET_UNLOCK(ifp);
        }

        /*
         * Take upper layers down.  We send the Down event first and
         * the Close second to prevent the upper layers from sending
         * ``a flurry of terminate-request packets'', as the RFC
         * describes it.
         */
        for (i = 0; i < IDX_COUNT; i++) {
                scp = &sp->scp[(cps[i])->protoidx];

                if (((cps[i])->flags & CP_LCP) == 0)
                        sppp_wq_add(sp->wq_cp, &scp->work_down);

                if ((cps[i])->flags & CP_AUTH) {
                        sppp_wq_add(sp->wq_cp, &scp->work_close);
                }

                /* Close all NCPs. */
                if (phase == SPPP_PHASE_NETWORK &&
                    ((cps[i])->flags & CP_NCP) != 0) {
                        sppp_wq_add(sp->wq_cp, &scp->work_close);
                }
        }
}

static void
sppp_lcp_tls(const struct cp *cp __unused, struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        sppp_change_phase(sp, SPPP_PHASE_ESTABLISH);

        /* Notify lower layer if desired. */
        if (!sp->lcp.lower_running) {
                sp->lcp.lower_running = true;
                sppp_notify_tls_wlocked(sp);
        }
}

static void
sppp_lcp_tlf(const struct cp *cp __unused, struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        sppp_change_phase(sp, SPPP_PHASE_DEAD);

        /* Notify lower layer if desired. */
        if (sp->lcp.lower_running) {
                sp->lcp.lower_running = false;
                sppp_notify_tlf_wlocked(sp);
        }
}

static void
sppp_lcp_scr(struct sppp *sp)
{
        char opt[6 /* magicnum */ + 4 /* mru */ + 5 /* chap */];
        int i = 0;
        u_short authproto;

        KASSERT(SPPP_WLOCKED(sp));

        if (ISSET(sp->lcp.opts, SPPP_LCP_OPT_MAGIC)) {
                if (! sp->lcp.magic)
                        sp->lcp.magic = cprng_fast32();
                opt[i++] = LCP_OPT_MAGIC;
                opt[i++] = 6;
                opt[i++] = sp->lcp.magic >> 24;
                opt[i++] = sp->lcp.magic >> 16;
                opt[i++] = sp->lcp.magic >> 8;
                opt[i++] = sp->lcp.magic;
        }

        if (ISSET(sp->lcp.opts,SPPP_LCP_OPT_MRU)) {
                opt[i++] = LCP_OPT_MRU;
                opt[i++] = 4;
                opt[i++] = sp->lcp.mru >> 8;
                opt[i++] = sp->lcp.mru;
        }

        if (ISSET(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO)) {
                authproto = sp->hisauth.proto;
                opt[i++] = LCP_OPT_AUTH_PROTO;
                opt[i++] = authproto == PPP_CHAP? 5: 4;
                opt[i++] = authproto >> 8;
                opt[i++] = authproto;
                if (authproto == PPP_CHAP)
                        opt[i++] = CHAP_MD5;
        }

        sp->scp[IDX_LCP].confid = ++sp->scp[IDX_LCP].seq;
        sppp_cp_send(sp, PPP_LCP, CONF_REQ, sp->scp[IDX_LCP].confid, i, &opt);
}

/*
 * Check the open NCPs, return true if at least one NCP is open.
 */

static int
sppp_cp_check(struct sppp *sp, u_char cp_flags)
{
        int i, mask;

        for (i = 0, mask = 1; i < IDX_COUNT; i++, mask <<= 1)
                if ((sp->lcp.protos & mask) && (cps[i])->flags & cp_flags)
                        return 1;
        return 0;
}

/*
 * Check the opened NCPs, return true if at least one NCP is opened.
 */
static bool
sppp_is_ncp_opened(struct sppp *sp)
{
        size_t i;

        for (i = 0; i < IDX_COUNT; i++)
                if (((cps[i])->flags & CP_NCP) &&
                    (sp->scp[i].state == STATE_OPENED))
                        return true;
        return false;
}

/*
 * Re-check the open NCPs and see if we should terminate the link.
 * Called by the NCPs during their tlf action handling.
 */
static void
sppp_lcp_check_and_close(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        if (sp->pp_phase < SPPP_PHASE_AUTHENTICATE) {
                /* don't bother, we are already going down */
                return;
        }

        if (sp->pp_phase == SPPP_PHASE_AUTHENTICATE &&
            sppp_cp_check(sp, CP_AUTH))
                return;

        if (sp->pp_phase >= SPPP_PHASE_NETWORK &&
            sppp_cp_check(sp, CP_NCP))
                return;

        if (sp->pp_max_auth_fail != 0 &&
            sp->pp_auth_failures >= sp->pp_max_auth_fail) {
                SPPP_LOG(sp, LOG_INFO, "authentication failed %d times, "
                    "not retrying again\n", sp->pp_auth_failures);

                sppp_wq_add(sp->wq_cp, &sp->work_ifdown);
                sppp_disconnect(sp);
        } else {
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_close);
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_open);
        }
}

/*
 *--------------------------------------------------------------------------*
 *                                                                          *
 *                        The IPCP implementation.                          *
 *                                                                          *
 *--------------------------------------------------------------------------*
 */

static void
sppp_ipcp_init(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        sppp_cp_init(&ipcp, sp);

        sp->ipcp.opts = 0;
        sp->ipcp.flags = 0;
}

static void
sppp_ipcp_open(struct sppp *sp, void *xcp)
{
        uint32_t myaddr, hisaddr;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        if (!ISSET(sp->pp_ncpflags, SPPP_NCP_IPCP))
                return;

        sp->ipcp.flags &= ~(IPCP_HISADDR_SEEN|IPCP_MYADDR_SEEN|IPCP_MYADDR_DYN|IPCP_HISADDR_DYN);
        sp->ipcp.req_myaddr = 0;
        sp->ipcp.req_hisaddr = 0;
        memset(&sp->dns_addrs, 0, sizeof sp->dns_addrs);

#ifdef INET
        sppp_get_ip_addrs(sp, &myaddr, &hisaddr, 0);
#else
        myaddr = hisaddr = 0;
#endif
        /*
         * If we don't have his address, this probably means our
         * interface doesn't want to talk IP at all.  (This could
         * be the case if somebody wants to speak only IPX, for
         * example.)  Don't open IPCP in this case.
         */
        if (hisaddr == 0) {
                /* XXX this message should go away */
                SPPP_DLOG(sp, "ipcp_open(): no IP interface\n");
                return;
        }

        if (myaddr == 0) {
                /*
                 * I don't have an assigned address, so i need to
                 * negotiate my address.
                 */
                sp->ipcp.flags |= IPCP_MYADDR_DYN;
                SET(sp->ipcp.opts, SPPP_IPCP_OPT_ADDRESS);
        }
        if (hisaddr == 1) {
                /*
                 * XXX - remove this hack!
                 * remote has no valid address, we need to get one assigned.
                 */
                sp->ipcp.flags |= IPCP_HISADDR_DYN;
                sp->ipcp.saved_hisaddr = htonl(hisaddr);
        }

        if (sp->query_dns & 1) {
                SET(sp->ipcp.opts, SPPP_IPCP_OPT_PRIMDNS);
        } else {
                CLR(sp->ipcp.opts, SPPP_IPCP_OPT_PRIMDNS);
        }

        if (sp->query_dns & 2) {
                SET(sp->ipcp.opts, SPPP_IPCP_OPT_SECDNS);
        } else {
                CLR(sp->ipcp.opts, SPPP_IPCP_OPT_SECDNS);
        }
        sppp_open_event(sp, xcp);
}

static void
sppp_ipcp_close(struct sppp *sp, void *xcp)
{

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        sppp_close_event(sp, xcp);

#ifdef INET
        if (sp->ipcp.flags & (IPCP_MYADDR_DYN|IPCP_HISADDR_DYN)) {
                /*
                 * Some address was dynamic, clear it again.
                 */
                sppp_clear_ip_addrs(sp);
        }
#endif
        memset(&sp->dns_addrs, 0, sizeof sp->dns_addrs);
}

/*
 * Analyze a configure request.  Return true if it was agreeable, and
 * caused action sca, false if it has been rejected or nak'ed, and
 * caused action scn.  (The return value is used to make the state
 * transition decision in the state automaton.)
 */
static enum cp_rcr_type
sppp_ipcp_confreq(struct sppp *sp, struct lcp_header *h, int origlen,
   uint8_t **msgbuf, size_t *buflen, size_t *msglen)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *buf, *r, *p, l, blen;
        enum cp_rcr_type type;
        int rlen, len;
        uint32_t hisaddr, desiredaddr;
        char ipbuf[SPPP_IPCPOPT_NAMELEN];
        char dqbuf[SPPP_DOTQUAD_BUFLEN];
        const char *dq;

        KASSERT(SPPP_WLOCKED(sp));

        type = CP_RCR_NONE;
        origlen -= sizeof(*h);

        if (origlen < 0)
                return CP_RCR_DROP;

        /*
         * Make sure to allocate a buf that can at least hold a
         * conf-nak with an `address' option.  We might need it below.
         */
        blen = MAX(6, origlen);

        buf = kmem_intr_alloc(blen, KM_NOSLEEP);
        if (buf == NULL)
                return CP_RCR_DROP;

        /* pass 1: see if we can recognize them */
        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipcp parse opts:");
        p = (void *)(h + 1);
        r = buf;
        rlen = 0;
        for (len = origlen; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                /* Sanity check option length */
                if (l > len) {
                        /* XXX should we just RXJ? */
                        if (debug)
                                addlog("\n");

                        SPPP_LOG(sp, LOG_DEBUG,
                            " malicious IPCP option received, dropping\n");
                        type = CP_RCR_ERR;
                        goto end;
                }
                if (debug) {
                        addlog(" %s",
                            sppp_ipcp_opt_name(ipbuf, sizeof(ipbuf), *p));
                }
                switch (p[0]) {
#ifdef notyet
                case IPCP_OPT_COMPRESSION:
                        if (len >= 6 && l >= 6) {
                                /* correctly formed compress option */
                                continue;
                        }
                        if (debug)
                                addlog(" [invalid]");
                        break;
#endif
                case IPCP_OPT_ADDRESS:
                        if (len >= 6 && l == 6) {
                                /* correctly formed address option */
                                continue;
                        }
                        if (debug)
                                addlog(" [invalid]");
                        break;
                default:
                        /* Others not supported. */
                        if (debug)
                                addlog(" [rej]");
                        break;
                }
                /* Add the option to rejected list. */
                if (rlen + l > blen) {
                        if (debug)
                                addlog(" [overflow]");
                        continue;
                }
                memcpy(r, p, l);
                r += l;
                rlen += l;
        }

        if (rlen > 0) {
                type = CP_RCR_REJ;
                goto end;
        }

        if (debug)
                addlog("\n");

        /* pass 2: parse option values */
        if (sp->ipcp.flags & IPCP_HISADDR_SEEN)
                hisaddr = sp->ipcp.req_hisaddr; /* we already aggreed on that */
        else
#ifdef INET
                sppp_get_ip_addrs(sp, 0, &hisaddr, 0);  /* user configuration */
#else
                hisaddr = 0;
#endif
        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipcp parse opt values:");
        p = (void *)(h + 1);
        r = buf;
        rlen = 0;
        for (len = origlen; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                if (debug) {
                        addlog(" %s",
                            sppp_ipcp_opt_name(ipbuf, sizeof(ipbuf), *p));
                }
                switch (p[0]) {
#ifdef notyet
                case IPCP_OPT_COMPRESSION:
                        continue;
#endif
                case IPCP_OPT_ADDRESS:
                        desiredaddr = p[2] << 24 | p[3] << 16 |
                                p[4] << 8 | p[5];
                        if (desiredaddr == hisaddr ||
                           ((sp->ipcp.flags & IPCP_HISADDR_DYN) && desiredaddr != 0)) {
                                /*
                                * Peer's address is same as our value,
                                * this is agreeable.  Gonna conf-ack
                                * it.
                                */
                                if (debug) {
                                        dq = sppp_dotted_quad(dqbuf,
                                            sizeof(dqbuf), hisaddr);
                                        addlog(" %s [ack]", dq);
                                }
                                /* record that we've seen it already */
                                sp->ipcp.flags |= IPCP_HISADDR_SEEN;
                                sp->ipcp.req_hisaddr = desiredaddr;
                                hisaddr = desiredaddr;
                                continue;
                        }
                        /*
                        * The address wasn't agreeable.  This is either
                        * he sent us 0.0.0.0, asking to assign him an
                        * address, or he send us another address not
                        * matching our value.  Either case, we gonna
                        * conf-nak it with our value.
                        */
                        if (debug) {
                                if (desiredaddr == 0) {
                                        addlog(" [addr requested]");
                                } else {
                                        dq = sppp_dotted_quad(dqbuf,
                                            sizeof(dqbuf), desiredaddr);
                                        addlog(" %s [not agreed]", dq);
                                }
                        }

                        p[2] = hisaddr >> 24;
                        p[3] = hisaddr >> 16;
                        p[4] = hisaddr >> 8;
                        p[5] = hisaddr;
                        break;
                }
                if (rlen + l > blen) {
                        if (debug)
                                addlog(" [overflow]");
                        continue;
                }
                /* Add the option to nak'ed list. */
                memcpy(r, p, l);
                r += l;
                rlen += l;
        }

        if (rlen > 0) {
                type = CP_RCR_NAK;
        } else {
                if ((sp->ipcp.flags & IPCP_HISADDR_SEEN) == 0) {
                        /*
                         * If we are about to conf-ack the request, but haven't seen
                         * his address so far, gonna conf-nak it instead, with the
                         * `address' option present and our idea of his address being
                         * filled in there, to request negotiation of both addresses.
                         *
                         * XXX This can result in an endless req - nak loop if peer
                         * doesn't want to send us his address.  Q: What should we do
                         * about it?  XXX  A: implement the max-failure counter.
                         */
                        buf[0] = IPCP_OPT_ADDRESS;
                        buf[1] = 6;
                        buf[2] = hisaddr >> 24;
                        buf[3] = hisaddr >> 16;
                        buf[4] = hisaddr >> 8;
                        buf[5] = hisaddr;
                        rlen = 6;
                        if (debug)
                                addlog(" still need hisaddr");
                        type = CP_RCR_NAK;
                } else {
                        type = CP_RCR_ACK;
                        rlen = origlen;
                        memcpy(r, h + 1, rlen);
                }
        }

end:
        if (debug)
                addlog("\n");

        if (type == CP_RCR_ERR || type == CP_RCR_DROP) {
                if (buf != NULL)
                        kmem_intr_free(buf, blen);
        } else {
                *msgbuf = buf;
                *buflen = blen;
                *msglen = rlen;
        }

        return type;
}

/*
 * Analyze the IPCP Configure-Reject option list, and adjust our
 * negotiation.
 */
static void
sppp_ipcp_confrej(struct sppp *sp, struct lcp_header *h, int len)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *p, l;

        KASSERT(SPPP_WLOCKED(sp));

        if (len <= sizeof(*h))
                return;

        len -= sizeof(*h);

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipcp rej opts:");

        p = (void *)(h + 1);
        for (; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                /* Sanity check option length */
                if (l > len) {
                        /* XXX should we just RXJ? */
                        if (debug)
                                addlog("\n");
                        SPPP_LOG(sp, LOG_DEBUG,
                            "malicious IPCP option received, dropping\n");
                        goto end;
                }
                if (debug) {
                        char ipbuf[SPPP_IPCPOPT_NAMELEN];
                        addlog(" %s",
                            sppp_ipcp_opt_name(ipbuf, sizeof(ipbuf), *p));
                }
                switch (p[0]) {
                case IPCP_OPT_ADDRESS:
                        /*
                         * Peer doesn't grok address option.  This is
                         * bad.  XXX  Should we better give up here?
                         */
                        if (!debug) {
                                SPPP_LOG(sp, LOG_ERR,
                                    "IPCP address option rejected\n");
                        }
                        CLR(sp->ipcp.opts, SPPP_IPCP_OPT_ADDRESS);
                        break;
#ifdef notyet
                case IPCP_OPT_COMPRESS:
                        CLR(sp->ipcp.opts, SPPP_IPCP_OPT_COMPRESS);
                        break;
#endif
                case IPCP_OPT_PRIMDNS:
                        CLR(sp->ipcp.opts, SPPP_IPCP_OPT_PRIMDNS);
                        break;

                case IPCP_OPT_SECDNS:
                        CLR(sp->ipcp.opts, SPPP_IPCP_OPT_SECDNS);
                        break;
                }
        }
        if (debug)
                addlog("\n");
end:
        return;
}

/*
 * Analyze the IPCP Configure-NAK option list, and adjust our
 * negotiation.
 */
static void
sppp_ipcp_confnak(struct sppp *sp, struct lcp_header *h, int len)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *p, l;
        uint32_t wantaddr;

        KASSERT(SPPP_WLOCKED(sp));

        len -= sizeof(*h);

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipcp nak opts:");

        p = (void *)(h + 1);
        for (; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                /* Sanity check option length */
                if (l > len) {
                        /* XXX should we just RXJ? */
                        if (debug)
                                addlog("\n");
                        SPPP_LOG(sp, LOG_DEBUG,
                            "malicious IPCP option received, dropping\n");
                        return;
                }
                if (debug) {
                        char ipbuf[SPPP_IPCPOPT_NAMELEN];
                        addlog(" %s",
                            sppp_ipcp_opt_name(ipbuf, sizeof(ipbuf), *p));
                }
                switch (*p) {
                case IPCP_OPT_ADDRESS:
                        /*
                         * Peer doesn't like our local IP address.  See
                         * if we can do something for him.  We'll drop
                         * him our address then.
                         */
                        if (len >= 6 && l == 6) {
                                wantaddr = p[2] << 24 | p[3] << 16 |
                                        p[4] << 8 | p[5];
                                SET(sp->ipcp.opts, SPPP_IPCP_OPT_ADDRESS);
                                if (debug) {
                                        char dqbuf[SPPP_DOTQUAD_BUFLEN];
                                        const char *dq;

                                        dq = sppp_dotted_quad(dqbuf,
                                            sizeof(dqbuf), wantaddr);
                                        addlog(" [wantaddr %s]", dq);
                                }
                                /*
                                 * When doing dynamic address assignment,
                                 * we accept his offer.  Otherwise, we
                                 * ignore it and thus continue to negotiate
                                 * our already existing value.
                                 */
                                if (sp->ipcp.flags & IPCP_MYADDR_DYN) {
                                        if (ntohl(wantaddr) != INADDR_ANY) {
                                                if (debug)
                                                        addlog(" [agree]");
                                                sp->ipcp.flags |= IPCP_MYADDR_SEEN;
                                                sp->ipcp.req_myaddr = wantaddr;
                                        } else {
                                                if (debug)
                                                        addlog(" [not agreed]");
                                        }
                                }
                        }
                        break;

                case IPCP_OPT_PRIMDNS:
                        if (ISSET(sp->ipcp.opts, SPPP_IPCP_OPT_PRIMDNS) &&
                            len >= 6 && l == 6) {
                                sp->dns_addrs[0] = p[2] << 24 | p[3] << 16 |
                                        p[4] << 8 | p[5];
                        }
                        break;

                case IPCP_OPT_SECDNS:
                        if (ISSET(sp->ipcp.opts, SPPP_IPCP_OPT_SECDNS) &&
                            len >= 6 && l == 6) {
                                sp->dns_addrs[1] = p[2] << 24 | p[3] << 16 |
                                        p[4] << 8 | p[5];
                        }
                        break;
#ifdef notyet
                case IPCP_OPT_COMPRESS:
                        /*
                         * Peer wants different compression parameters.
                         */
                        break;
#endif
                }
        }
        if (debug)
                addlog("\n");
}

/*
 * rt_ifmsg requires sppp to be unlocked as it will attempt to lock it again.
 * unlocking sppp is safe here because this logic runs in a single thread,
 * the workqueue, so concurrent state transitions are excluded on that basis;
 * other tlu functions already release and re-acquire the lock already,
 * which is only for coordination with threads _other_ than the workqueue
 * thread which doesn't change the state.
 */
static void
sppp_rt_ifmsg(struct sppp *sp)
{
        struct ifnet *ifp = &sp->pp_if;

        KASSERT(SPPP_WLOCKED(sp));

        SPPP_UNLOCK(sp);
        rt_ifmsg(ifp);
        SPPP_LOCK(sp, RW_WRITER);
}

static void
sppp_ipcp_tlu(struct sppp *sp)
{
#ifdef INET

        KASSERT(SPPP_WLOCKED(sp));

        SPPP_LOG(sp, LOG_INFO, "IPCP layer up\n");
        if ((sp->ipcp.flags & IPCP_MYADDR_DYN) &&
            ((sp->ipcp.flags & IPCP_MYADDR_SEEN) == 0)) {
                SPPP_LOG(sp, LOG_WARNING,
                    "no IP address, closing IPCP\n");
                sppp_wq_add(sp->wq_cp,
                    &sp->scp[IDX_IPCP].work_close);
        } else {
                /* we are up. Set addresses and notify anyone interested */
                sppp_set_ip_addrs(sp);
                sppp_rt_ifmsg(sp);
        }
#endif
}

static void
sppp_ipcp_tld(struct sppp *sp)
{
#ifdef INET

        SPPP_LOG(sp, LOG_INFO, "IPCP layer down\n");
        sppp_rt_ifmsg(sp);
#endif
}

static void
sppp_ipcp_scr(struct sppp *sp)
{
        uint8_t opt[6 /* compression */ + 6 /* address */ + 12 /* dns addresses */];
#ifdef INET
        uint32_t ouraddr;
#endif
        int i = 0;

        KASSERT(SPPP_WLOCKED(sp));

#ifdef notyet
        if (ISSET(sp->ipcp.opts,SPPP_IPCP_OPT_COMPRESSION)) {
                opt[i++] = IPCP_OPT_COMPRESSION;
                opt[i++] = 6;
                opt[i++] = 0;   /* VJ header compression */
                opt[i++] = 0x2d; /* VJ header compression */
                opt[i++] = max_slot_id;
                opt[i++] = comp_slot_id;
        }
#endif

#ifdef INET
        if (ISSET(sp->ipcp.opts, SPPP_IPCP_OPT_ADDRESS)) {
                if (sp->ipcp.flags & IPCP_MYADDR_SEEN) {
                        ouraddr = sp->ipcp.req_myaddr;  /* not sure if this can ever happen */
                } else {
                        sppp_get_ip_addrs(sp, &ouraddr, 0, 0);
                }
                opt[i++] = IPCP_OPT_ADDRESS;
                opt[i++] = 6;
                opt[i++] = ouraddr >> 24;
                opt[i++] = ouraddr >> 16;
                opt[i++] = ouraddr >> 8;
                opt[i++] = ouraddr;
        }
#endif

        if (ISSET(sp->ipcp.opts, SPPP_IPCP_OPT_PRIMDNS)) {
                opt[i++] = IPCP_OPT_PRIMDNS;
                opt[i++] = 6;
                opt[i++] = sp->dns_addrs[0] >> 24;
                opt[i++] = sp->dns_addrs[0] >> 16;
                opt[i++] = sp->dns_addrs[0] >> 8;
                opt[i++] = sp->dns_addrs[0];
        }
        if (ISSET(sp->ipcp.opts, SPPP_IPCP_OPT_SECDNS)) {
                opt[i++] = IPCP_OPT_SECDNS;
                opt[i++] = 6;
                opt[i++] = sp->dns_addrs[1] >> 24;
                opt[i++] = sp->dns_addrs[1] >> 16;
                opt[i++] = sp->dns_addrs[1] >> 8;
                opt[i++] = sp->dns_addrs[1];
        }

        sp->scp[IDX_IPCP].confid = ++sp->scp[IDX_IPCP].seq;
        sppp_cp_send(sp, PPP_IPCP, CONF_REQ, sp->scp[IDX_IPCP].confid, i, &opt);
}

/*
 *--------------------------------------------------------------------------*
 *                                                                          *
 *                      The IPv6CP implementation.                          *
 *                                                                          *
 *--------------------------------------------------------------------------*
 */

#ifdef INET6
static void
sppp_ipv6cp_init(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        sppp_cp_init(&ipv6cp, sp);

        sp->ipv6cp.opts = 0;
        sp->ipv6cp.flags = 0;
}

static void
sppp_ipv6cp_open(struct sppp *sp, void *xcp)
{
        struct in6_addr myaddr, hisaddr;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        if (!ISSET(sp->pp_ncpflags, SPPP_NCP_IPV6CP))
                return;

#ifdef IPV6CP_MYIFID_DYN
        sp->ipv6cp.flags &= ~(IPV6CP_MYIFID_SEEN|IPV6CP_MYIFID_DYN);
#else
        sp->ipv6cp.flags &= ~IPV6CP_MYIFID_SEEN;
#endif

        sppp_get_ip6_addrs(sp, &myaddr, &hisaddr, 0);
        /*
         * If we don't have our address, this probably means our
         * interface doesn't want to talk IPv6 at all.  (This could
         * be the case if somebody wants to speak only IPX, for
         * example.)  Don't open IPv6CP in this case.
         */
        if (IN6_IS_ADDR_UNSPECIFIED(&myaddr)) {
                /* XXX this message should go away */
                SPPP_DLOG(sp, "ipv6cp_open(): no IPv6 interface\n");
                return;
        }

        sp->ipv6cp.flags |= IPV6CP_MYIFID_SEEN;
        SET(sp->ipv6cp.opts, SPPP_IPV6CP_OPT_IFID);
        sppp_open_event(sp, xcp);
}

/*
 * Analyze a configure request.  Return true if it was agreeable, and
 * caused action sca, false if it has been rejected or nak'ed, and
 * caused action scn.  (The return value is used to make the state
 * transition decision in the state automaton.)
 */
static enum cp_rcr_type
sppp_ipv6cp_confreq(struct sppp *sp, struct lcp_header *h, int origlen,
    uint8_t **msgbuf, size_t *buflen, size_t *msglen)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *buf, *r, *p, l, blen;
        int rlen, len;
        struct in6_addr myaddr, desiredaddr, suggestaddr;
        enum cp_rcr_type type;
        int ifidcount;
        int collision, nohisaddr;
        char ip6buf[INET6_ADDRSTRLEN];
        char tbuf[SPPP_CPTYPE_NAMELEN];
        char ipv6buf[SPPP_IPV6CPOPT_NAMELEN];
        const char *cpname;

        KASSERT(SPPP_WLOCKED(sp));

        type = CP_RCR_NONE;
        origlen -= sizeof(*h);

        if (origlen < 0)
                return CP_RCR_DROP;

        /*
         * Make sure to allocate a buf that can at least hold a
         * conf-nak with an `address' option.  We might need it below.
         */
        blen = MAX(6, origlen);

        buf = kmem_intr_alloc(blen, KM_NOSLEEP);
        if (buf == NULL)
                return CP_RCR_DROP;

        /* pass 1: see if we can recognize them */
        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipv6cp parse opts:");
        p = (void *)(h + 1);
        r = buf;
        rlen = 0;
        ifidcount = 0;
        for (len = origlen; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                /* Sanity check option length */
                if (l > len) {
                        /* XXX just RXJ? */
                        if (debug)
                                addlog("\n");
                        SPPP_LOG(sp, LOG_DEBUG,
                            "received malicious IPCPv6 option, "
                            "dropping\n");
                        type = CP_RCR_ERR;
                        goto end;
                }
                if (debug) {
                        addlog(" %s", sppp_ipv6cp_opt_name(ipv6buf,
                            sizeof(ipv6buf),*p));
                }
                switch (p[0]) {
                case IPV6CP_OPT_IFID:
                        if (len >= 10 && l == 10 && ifidcount == 0) {
                                /* correctly formed address option */
                                ifidcount++;
                                continue;
                        }
                        if (debug)
                                addlog(" [invalid]");
                        break;
#ifdef notyet
                case IPV6CP_OPT_COMPRESSION:
                        if (len >= 4 && l >= 4) {
                                /* correctly formed compress option */
                                continue;
                        }
                        if (debug)
                                addlog(" [invalid]");
                        break;
#endif
                default:
                        /* Others not supported. */
                        if (debug)
                                addlog(" [rej]");
                        break;
                }
                if (rlen + l > blen) {
                        if (debug)
                                addlog(" [overflow]");
                        continue;
                }
                /* Add the option to rejected list. */
                memcpy(r, p, l);
                r += l;
                rlen += l;
        }

        if (rlen > 0) {
                type = CP_RCR_REJ;
                goto end;
        }

        if (debug)
                addlog("\n");

        /* pass 2: parse option values */
        sppp_get_ip6_addrs(sp, &myaddr, 0, 0);
        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipv6cp parse opt values:");
        p = (void *)(h + 1);
        r = buf;
        rlen = 0;
        type = CP_RCR_ACK;
        for (len = origlen; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                if (debug) {
                        addlog(" %s", sppp_ipv6cp_opt_name(ipv6buf,
                            sizeof(ipv6buf), *p));
                }
                switch (p[0]) {
#ifdef notyet
                case IPV6CP_OPT_COMPRESSION:
                        continue;
#endif
                case IPV6CP_OPT_IFID:
                        memset(&desiredaddr, 0, sizeof(desiredaddr));
                        memcpy(&desiredaddr.s6_addr[8], &p[2], 8);
                        collision = (memcmp(&desiredaddr.s6_addr[8],
                                        &myaddr.s6_addr[8], 8) == 0);
                        nohisaddr = IN6_IS_ADDR_UNSPECIFIED(&desiredaddr);

                        desiredaddr.s6_addr16[0] = htons(0xfe80);
                        (void)in6_setscope(&desiredaddr, &sp->pp_if, NULL);

                        if (!collision && !nohisaddr) {
                                /* no collision, hisaddr known - Conf-Ack */
                                type = CP_RCR_ACK;
                                memcpy(sp->ipv6cp.my_ifid, &myaddr.s6_addr[8],
                                    sizeof(sp->ipv6cp.my_ifid));
                                memcpy(sp->ipv6cp.his_ifid,
                                    &desiredaddr.s6_addr[8],
                                    sizeof(sp->ipv6cp.my_ifid));

                                if (debug) {
                                        cpname = sppp_cp_type_name(tbuf,
                                            sizeof(tbuf), CONF_ACK);
                                        addlog(" %s [%s]",
                                            IN6_PRINT(ip6buf, &desiredaddr),
                                            cpname);
                                }
                                continue;
                        }

                        memset(&suggestaddr, 0, sizeof(suggestaddr));
                        if (collision && nohisaddr) {
                                /* collision, hisaddr unknown - Conf-Rej */
                                type = CP_RCR_REJ;
                                memset(&p[2], 0, 8);
                        } else {
                                /*
                                 * - no collision, hisaddr unknown, or
                                 * - collision, hisaddr known
                                 * Conf-Nak, suggest hisaddr
                                 */
                                type = CP_RCR_NAK;
                                sppp_suggest_ip6_addr(sp, &suggestaddr);
                                memcpy(&p[2], &suggestaddr.s6_addr[8], 8);
                        }
                        if (debug) {
                                int ctype = type == CP_RCR_REJ ? CONF_REJ : CONF_NAK;

                                cpname = sppp_cp_type_name(tbuf, sizeof(tbuf), ctype);
                                addlog(" %s [%s]", IN6_PRINT(ip6buf, &desiredaddr),
                                   cpname);
                        }
                        break;
                }
                if (rlen + l > blen) {
                        if (debug)
                                addlog(" [overflow]");
                        continue;
                }
                /* Add the option to nak'ed list. */
                memcpy(r, p, l);
                r += l;
                rlen += l;
        }

        if (rlen > 0) {
                if (type != CP_RCR_ACK) {
                        if (debug) {
                                int ctype ;
                                ctype = type == CP_RCR_REJ ?
                                    CONF_REJ : CONF_NAK;
                                cpname =  sppp_cp_type_name(tbuf, sizeof(tbuf), ctype);
                                addlog(" send %s suggest %s\n",
                                    cpname, IN6_PRINT(ip6buf, &suggestaddr));
                        }
                }
#ifdef notdef
                if (type == CP_RCR_ACK)
                        panic("IPv6CP RCR: CONF_ACK with non-zero rlen");
#endif
        } else {
                if (type == CP_RCR_ACK) {
                        rlen = origlen;
                        memcpy(r, h + 1, rlen);
                }
        }
end:
        if (debug)
                addlog("\n");

        if (type == CP_RCR_ERR || type == CP_RCR_DROP) {
                if (buf != NULL)
                        kmem_intr_free(buf, blen);
        } else {
                *msgbuf = buf;
                *buflen = blen;
                *msglen = rlen;
        }

        return type;
}

/*
 * Analyze the IPv6CP Configure-Reject option list, and adjust our
 * negotiation.
 */
static void
sppp_ipv6cp_confrej(struct sppp *sp, struct lcp_header *h, int len)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *p, l;

        KASSERT(SPPP_WLOCKED(sp));

        if (len <= sizeof(*h))
                return;

        len -= sizeof(*h);

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipv6cp rej opts:");

        p = (void *)(h + 1);
        for (; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                if (l > len) {
                        /* XXX just RXJ? */
                        if (debug)
                                addlog("\n");
                        SPPP_LOG(sp, LOG_DEBUG,
                            "received malicious IPCPv6 option, "
                            "dropping\n");
                        goto end;
                }
                if (debug) {
                        char ipv6buf[SPPP_IPV6CPOPT_NAMELEN];
                        addlog(" %s", sppp_ipv6cp_opt_name(ipv6buf,
                            sizeof(ipv6buf), *p));
                }
                switch (p[0]) {
                case IPV6CP_OPT_IFID:
                        /*
                         * Peer doesn't grok address option.  This is
                         * bad.  XXX  Should we better give up here?
                         */
                        CLR(sp->ipv6cp.opts, SPPP_IPV6CP_OPT_IFID);
                        break;
#ifdef notyet
                case IPV6CP_OPT_COMPRESS:
                        CLR(sp->ipv6cp.opts, SPPP_IPV6CP_OPT_COMPRESS);
                        break;
#endif
                }
        }
        if (debug)
                addlog("\n");
end:
        return;
}

/*
 * Analyze the IPv6CP Configure-NAK option list, and adjust our
 * negotiation.
 */
static void
sppp_ipv6cp_confnak(struct sppp *sp, struct lcp_header *h, int len)
{
        const bool debug = sppp_debug_enabled(sp);
        u_char *p, l;
        struct in6_addr suggestaddr;
        char ip6buf[INET6_ADDRSTRLEN];

        KASSERT(SPPP_WLOCKED(sp));

        if (len <= sizeof(*h))
                return;

        len -= sizeof(*h);

        if (debug)
                SPPP_LOG(sp, LOG_DEBUG, "ipv6cp nak opts:");

        p = (void *)(h + 1);
        for (; len > 1; len -= l, p += l) {
                l = p[1];
                if (l == 0)
                        break;

                if (l > len) {
                        /* XXX just RXJ? */
                        if (debug)
                                addlog("\n");
                        SPPP_LOG(sp, LOG_DEBUG,
                            "received malicious IPCPv6 option, "
                            "dropping\n");
                        goto end;
                }
                if (debug) {
                        char ipv6buf[SPPP_IPV6CPOPT_NAMELEN];
                        addlog(" %s", sppp_ipv6cp_opt_name(ipv6buf,
                            sizeof(ipv6buf), *p));
                }
                switch (p[0]) {
                case IPV6CP_OPT_IFID:
                        /*
                         * Peer doesn't like our local ifid.  See
                         * if we can do something for him.  We'll drop
                         * him our address then.
                         */
                        if (len < 10 || l != 10)
                                break;
                        memset(&suggestaddr, 0, sizeof(suggestaddr));
                        suggestaddr.s6_addr16[0] = htons(0xfe80);
                        (void)in6_setscope(&suggestaddr, &sp->pp_if, NULL);
                        memcpy(&suggestaddr.s6_addr[8], &p[2], 8);

                        SET(sp->ipv6cp.opts, SPPP_IPV6CP_OPT_IFID);
                        if (debug)
                                addlog(" [suggestaddr %s]",
                                       IN6_PRINT(ip6buf, &suggestaddr));
#ifdef IPV6CP_MYIFID_DYN
                        /*
                         * When doing dynamic address assignment,
                         * we accept his offer.
                         */
                        if (sp->ipv6cp.flags & IPV6CP_MYIFID_DYN) {
                                struct in6_addr lastsuggest;
                                /*
                                 * If <suggested myaddr from peer> equals to
                                 * <hisaddr we have suggested last time>,
                                 * we have a collision.  generate new random
                                 * ifid.
                                 */
                                sppp_suggest_ip6_addr(&lastsuggest);
                                if (IN6_ARE_ADDR_EQUAL(&suggestaddr,
                                                 lastsuggest)) {
                                        if (debug)
                                                addlog(" [random]");
                                        sppp_gen_ip6_addr(sp, &suggestaddr);
                                }
                                sppp_set_ip6_addr(sp, &suggestaddr, 0);
                                if (debug)
                                        addlog(" [agree]");
                                sp->ipv6cp.flags |= IPV6CP_MYIFID_SEEN;
                        }
#else
                        /*
                         * Since we do not do dynamic address assignment,
                         * we ignore it and thus continue to negotiate
                         * our already existing value.  This can possibly
                         * go into infinite request-reject loop.
                         *
                         * This is not likely because we normally use
                         * ifid based on MAC-address.
                         * If you have no ethernet card on the node, too bad.
                         * XXX should we use fail_counter?
                         */
#endif
                        break;
#ifdef notyet
                case IPV6CP_OPT_COMPRESS:
                        /*
                         * Peer wants different compression parameters.
                         */
                        break;
#endif
                }
        }
        if (debug)
                addlog("\n");
end:
        return;
}

static void
sppp_ipv6cp_tlu(struct sppp *sp)
{

        SPPP_LOG(sp, LOG_INFO, "IPv6CP layer up\n");
        sppp_rt_ifmsg(sp);
}

static void
sppp_ipv6cp_tld(struct sppp *sp)
{

        SPPP_LOG(sp, LOG_INFO, "IPv6CP layer down\n");
        sppp_rt_ifmsg(sp);
}

static void
sppp_ipv6cp_scr(struct sppp *sp)
{
        char opt[10 /* ifid */ + 4 /* compression, minimum */];
        struct in6_addr ouraddr;
        int i = 0;

        KASSERT(SPPP_WLOCKED(sp));

        if (ISSET(sp->ipv6cp.opts, SPPP_IPV6CP_OPT_IFID)) {
                sppp_get_ip6_addrs(sp, &ouraddr, 0, 0);

                opt[i++] = IPV6CP_OPT_IFID;
                opt[i++] = 10;
                memcpy(&opt[i], &ouraddr.s6_addr[8], 8);
                i += 8;
        }

#ifdef notyet
        if (ISSET(sp->ipv6cp.opts, SPPP_IPV6CP_OPT_COMPRESSION)) {
                opt[i++] = IPV6CP_OPT_COMPRESSION;
                opt[i++] = 4;
                opt[i++] = 0;   /* TBD */
                opt[i++] = 0;   /* TBD */
                /* variable length data may follow */
        }
#endif

        sp->scp[IDX_IPV6CP].confid = ++sp->scp[IDX_IPV6CP].seq;
        sppp_cp_send(sp, PPP_IPV6CP, CONF_REQ, sp->scp[IDX_IPV6CP].confid, i, &opt);
}
#else /*INET6*/
static void
sppp_ipv6cp_init(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));
}

static void
sppp_ipv6cp_open(struct sppp *sp, void *xcp)
{

        KASSERT(SPPP_WLOCKED(sp));
}

static enum cp_rcr_type
sppp_ipv6cp_confreq(struct sppp *sp, struct lcp_header *h,
    int len, uint8_t **msgbuf, size_t *buflen, size_t *msglen)
{

        KASSERT(SPPP_WLOCKED(sp));
        return 0;
}

static void
sppp_ipv6cp_confrej(struct sppp *sp, struct lcp_header *h,
                    int len)
{

        KASSERT(SPPP_WLOCKED(sp));
}

static void
sppp_ipv6cp_confnak(struct sppp *sp, struct lcp_header *h,
                    int len)
{

        KASSERT(SPPP_WLOCKED(sp));
}

static void
sppp_ipv6cp_tlu(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));
}

static void
sppp_ipv6cp_tld(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));
}

static void
sppp_ipv6cp_scr(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));
}
#endif /*INET6*/

/*
 *--------------------------------------------------------------------------*
 *                                                                          *
 *                        The CHAP implementation.                          *
 *                                                                          *
 *--------------------------------------------------------------------------*
 */
/*
 * The authentication protocols is implemented on the state machine for
 * control protocols. And it uses following actions and events.
 *
 * Actions:
 *    - scr: send CHAP_CHALLENGE and CHAP_RESPONSE
 *    - sca: send CHAP_SUCCESS
 *    - scn: send CHAP_FAILURE and shutdown lcp
 * Events:
 *    - RCR+: receive CHAP_RESPONSE containing correct digest
 *    - RCR-: receive CHAP_RESPONSE containing wrong digest
 *    - RCA: receive CHAP_SUCCESS
 *    - RCN: (this event is unused)
 *    - TO+: re-send CHAP_CHALLENGE and CHAP_RESPONSE
 *    - TO-: this layer finish
 */

/*
 * Handle incoming CHAP packets.
 */
void
sppp_chap_input(struct sppp *sp, struct mbuf *m)
{
        const bool debug = sppp_debug_enabled(sp);
        struct ifnet *ifp = &sp->pp_if;
        struct lcp_header *h;
        int len = m->m_pkthdr.len;
        u_char *value, *name, digest[sizeof(sp->chap.challenge)];
        int value_len, name_len;
        MD5_CTX ctx;
        char abuf[SPPP_AUTHTYPE_NAMELEN];
        const char *authname;

        KASSERT(SPPP_WLOCKED(sp));

        if (len < 4) {
                SPPP_DLOG(sp, "chap invalid packet length: "
                    "%d bytes\n", len);
                return;
        }
        h = mtod(m, struct lcp_header *);
        if (len > ntohs(h->len))
                len = ntohs(h->len);

        switch (h->type) {
        /* challenge, failure and success are his authproto */
        case CHAP_CHALLENGE:
                if (sp->myauth.secret == NULL || sp->myauth.name == NULL) {
                        /* can't do anything useful */
                        sp->pp_auth_failures++;
                        SPPP_DLOG(sp, "chap input "
                            "without my name and my secret being set\n");
                        break;
                }
                value = 1 + (u_char *)(h + 1);
                value_len = value[-1];
                name = value + value_len;
                name_len = len - value_len - 5;
                if (name_len < 0) {
                        if (debug) {
                                authname = sppp_auth_type_name(abuf,
                                    sizeof(abuf), PPP_CHAP, h->type);
                                SPPP_LOG(sp, LOG_DEBUG,
                                    "chap corrupted challenge "
                                    "<%s id=0x%x len=%d",
                                    authname, h->ident, ntohs(h->len));
                                if (len > 4)
                                        sppp_print_bytes((u_char *)(h + 1),
                                            len - 4);
                                addlog(">\n");
                        }
                        break;
                }

                if (debug) {
                        authname = sppp_auth_type_name(abuf,
                            sizeof(abuf), PPP_CHAP, h->type);
                        SPPP_LOG(sp, LOG_DEBUG,
                            "chap input <%s id=0x%x len=%d name=",
                            authname, h->ident, ntohs(h->len));
                        sppp_print_string((char *) name, name_len);
                        addlog(" value-size=%d value=", value_len);
                        sppp_print_bytes(value, value_len);
                        addlog(">\n");
                }

                /* Compute reply value. */
                MD5Init(&ctx);
                MD5Update(&ctx, &h->ident, 1);
                MD5Update(&ctx, sp->myauth.secret, sp->myauth.secret_len);
                MD5Update(&ctx, value, value_len);
                MD5Final(sp->chap.digest, &ctx);
                sp->chap.digest_len = sizeof(sp->chap.digest);
                sp->scp[IDX_CHAP].rconfid = h->ident;

                sppp_wq_add(sp->wq_cp, &sp->chap.work_challenge_rcvd);
                break;

        case CHAP_SUCCESS:
                if (debug) {
                        SPPP_LOG(sp, LOG_DEBUG, "chap success");
                        if (len > 4) {
                                addlog(": ");
                                sppp_print_string((char *)(h + 1), len - 4);
                        }
                        addlog("\n");
                }

                if (h->ident != sp->scp[IDX_CHAP].rconfid) {
                        SPPP_DLOG(sp, "%s id mismatch 0x%x != 0x%x\n",
                            chap.name, h->ident,
                            sp->scp[IDX_CHAP].rconfid);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                if (sp->chap.digest_len == 0) {
                        SPPP_DLOG(sp, "receive CHAP success"
                            " without challenge\n");
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                sp->pp_auth_failures = 0;
                sp->pp_flags &= ~PP_NEEDAUTH;
                memset(sp->chap.digest, 0, sizeof(sp->chap.digest));
                sp->chap.digest_len = 0;

                if (!ISSET(sppp_auth_role(&chap, sp), SPPP_AUTH_SERV)) {
                        /*
                         * we are not authenticator for CHAP,
                         * generate a dummy RCR+ event without CHAP_RESPONSE
                         */
                        sp->scp[IDX_CHAP].rcr_type = CP_RCR_ACK;
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_CHAP].work_rcr);
                }
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_CHAP].work_rca);
                break;

        case CHAP_FAILURE:
                if (h->ident != sp->scp[IDX_CHAP].rconfid) {
                        SPPP_DLOG(sp, "%s id mismatch 0x%x != 0x%x\n",
                            chap.name, h->ident, sp->scp[IDX_CHAP].rconfid);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                if (sp->chap.digest_len == 0) {
                        SPPP_DLOG(sp, "receive CHAP failure "
                            "without challenge\n");
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                sp->pp_auth_failures++;
                SPPP_LOG(sp, LOG_INFO, "chap failure");
                if (debug) {
                        if (len > 4) {
                                addlog(": ");
                                sppp_print_string((char *)(h + 1), len - 4);
                        }
                }
                addlog("\n");

                memset(sp->chap.digest, 0, sizeof(sp->chap.digest));
                sp->chap.digest_len = 0;
                /*
                 * await LCP shutdown by authenticator,
                 * so we don't have to enqueue sc->scp[IDX_CHAP].work_rcn
                 */
                break;

        /* response is my authproto */
        case CHAP_RESPONSE:
                if (sp->hisauth.name == NULL || sp->hisauth.secret == NULL) {
                        /* can't do anything useful */
                        SPPP_DLOG(sp, "chap response "
                            "without his name and his secret being set\n");
                        break;
                }
                value = 1 + (u_char *)(h + 1);
                value_len = value[-1];
                name = value + value_len;
                name_len = len - value_len - 5;
                if (name_len < 0) {
                        if (debug) {
                                authname = sppp_auth_type_name(abuf,
                                    sizeof(abuf), PPP_CHAP, h->type);
                                SPPP_LOG(sp, LOG_DEBUG,
                                    "chap corrupted response "
                                    "<%s id=0x%x len=%d",
                                    authname, h->ident, ntohs(h->len));
                                if (len > 4)
                                        sppp_print_bytes((u_char *)(h + 1),
                                            len - 4);
                                addlog(">\n");
                        }
                        break;
                }
                if (h->ident != sp->scp[IDX_CHAP].confid) {
                        SPPP_DLOG(sp, "chap dropping response for old ID "
                            "(got %d, expected %d)\n",
                            h->ident, sp->scp[IDX_CHAP].confid);
                        break;
                } else {
                        sp->scp[IDX_CHAP].rconfid = h->ident;
                }

                if (sp->hisauth.name != NULL &&
                    (name_len != sp->hisauth.name_len
                    || memcmp(name, sp->hisauth.name, name_len) != 0)) {
                        SPPP_LOG(sp, LOG_INFO,
                            "chap response, his name ");
                        sppp_print_string(name, name_len);
                        addlog(" != expected ");
                        sppp_print_string(sp->hisauth.name,
                                          sp->hisauth.name_len);
                        addlog("\n");

                        /* generate RCR- event */
                        sp->scp[IDX_CHAP].rcr_type = CP_RCR_NAK;
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_CHAP].work_rcr);
                        break;
                }

                if (debug) {
                        authname = sppp_auth_type_name(abuf,
                            sizeof(abuf), PPP_CHAP, h->type);
                        SPPP_LOG(sp, LOG_DEBUG, "chap input(%s) "
                            "<%s id=0x%x len=%d name=",
                            sppp_state_name(sp->scp[IDX_CHAP].state),
                            authname, h->ident, ntohs(h->len));
                        sppp_print_string((char *)name, name_len);
                        addlog(" value-size=%d value=", value_len);
                        sppp_print_bytes(value, value_len);
                        addlog(">\n");
                }

                if (value_len == sizeof(sp->chap.challenge) &&
                    value_len == sizeof(sp->chap.digest)) {
                        MD5Init(&ctx);
                        MD5Update(&ctx, &h->ident, 1);
                        MD5Update(&ctx, sp->hisauth.secret, sp->hisauth.secret_len);
                        MD5Update(&ctx, sp->chap.challenge, sizeof(sp->chap.challenge));
                        MD5Final(digest, &ctx);

                        if (memcmp(digest, value, value_len) == 0) {
                                sp->scp[IDX_CHAP].rcr_type = CP_RCR_ACK;
                        } else {
                                sp->scp[IDX_CHAP].rcr_type = CP_RCR_NAK;
                        }
                } else {
                        if (debug) {
                                SPPP_LOG(sp, LOG_DEBUG,
                                    "chap bad hash value length: "
                                    "%d bytes, should be %zu\n",
                                    value_len, sizeof(sp->chap.challenge));
                        }

                        sp->scp[IDX_CHAP].rcr_type = CP_RCR_NAK;
                }

                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_CHAP].work_rcr);

                /* generate a dummy RCA event */
                if (sp->scp[IDX_CHAP].rcr_type == CP_RCR_ACK &&
                    (!ISSET(sppp_auth_role(&chap, sp), SPPP_AUTH_PEER) ||
                    sp->chap.rechallenging)) {
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_CHAP].work_rca);
                }
                break;

        default:
                /* Unknown CHAP packet type -- ignore. */
                if (debug) {
                        SPPP_LOG(sp, LOG_DEBUG, "chap unknown input(%s) "
                            "<0x%x id=0x%xh len=%d",
                            sppp_state_name(sp->scp[IDX_CHAP].state),
                            h->type, h->ident, ntohs(h->len));
                        if (len > 4)
                                sppp_print_bytes((u_char *)(h + 1), len - 4);
                        addlog(">\n");
                }
                break;

        }
}

static void
sppp_chap_init(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        sppp_cp_init(&chap, sp);

        SPPP_WQ_SET(&sp->chap.work_challenge_rcvd,
            sppp_chap_rcv_challenge_event, &chap);
}

static void
sppp_chap_open(struct sppp *sp, void *xcp)
{

        KASSERT(SPPP_WLOCKED(sp));

        memset(sp->chap.digest, 0, sizeof(sp->chap.digest));
        sp->chap.digest_len = 0;
        sp->chap.rechallenging = false;
        sp->chap.response_rcvd = false;
        sppp_open_event(sp, xcp);
}

static void
sppp_chap_tlu(struct sppp *sp)
{
        int i;

        KASSERT(SPPP_WLOCKED(sp));

        i = 0;
        sp->scp[IDX_CHAP].rst_counter = sp->lcp.max_configure;
        sp->pp_auth_failures = 0;

        SPPP_LOG(sp, LOG_DEBUG, "chap %s",
            sp->pp_phase == SPPP_PHASE_NETWORK ? "reconfirmed" : "tlu");

        /*
         * Some broken CHAP implementations (Conware CoNet, firmware
         * 4.0.?) don't want to re-authenticate their CHAP once the
         * initial challenge-response exchange has taken place.
         * Provide for an option to avoid rechallenges.
         */
        if (ISSET(sppp_auth_role(&chap, sp), SPPP_AUTH_SERV) &&
            (sp->hisauth.flags & SPPP_AUTHFLAG_NORECHALLENGE) == 0) {
                /*
                 * Compute the re-challenge timeout.  This will yield
                 * a number between 300 and 810 seconds.
                 */
                i = 300 + ((unsigned)(cprng_fast32() & 0xff00) >> 7);
                callout_schedule(&sp->scp[IDX_CHAP].ch, i * hz);

                if (sppp_debug_enabled(sp)) {
                        addlog(", next rechallenge in %d seconds", i);
                }
        }

        addlog("\n");

        /*
         * If we are already in phase network, we are done here.  This
         * is the case if this is a dummy tlu event after a re-challenge.
         */
        if (sp->pp_phase != SPPP_PHASE_NETWORK)
                sppp_phase_network(sp);
}

static void
sppp_chap_scr(struct sppp *sp)
{
        uint32_t *ch;
        u_char clen, dsize;
        int role;

        KASSERT(SPPP_WLOCKED(sp));

        role = sppp_auth_role(&chap, sp);

        if (ISSET(role, SPPP_AUTH_SERV) &&
            !sp->chap.response_rcvd) {
                /* we are authenticator for CHAP, send challenge */
                ch = (uint32_t *)sp->chap.challenge;
                clen = sizeof(sp->chap.challenge);
                /* Compute random challenge. */
                cprng_strong(kern_cprng, ch, clen, 0);

                sp->scp[IDX_CHAP].confid = ++sp->scp[IDX_CHAP].seq;
                sppp_auth_send(&chap, sp, CHAP_CHALLENGE, sp->scp[IDX_CHAP].confid,
                    sizeof(clen), (const char *)&clen,
                    sizeof(sp->chap.challenge), sp->chap.challenge,
                    0);
        }

        if (ISSET(role, SPPP_AUTH_PEER) &&
            sp->chap.digest_len > 0) {
                /* we are peer for CHAP, send response */
                dsize = sp->chap.digest_len;

                sppp_auth_send(&chap, sp, CHAP_RESPONSE, sp->scp[IDX_CHAP].rconfid,
                    sizeof(dsize), (const char *)&dsize,
                    sp->chap.digest_len, sp->chap.digest,
                    sp->myauth.name_len, sp->myauth.name, 0);
        }
}

static void
sppp_chap_rcv_challenge_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;

        KASSERT(!cpu_softintr_p());

        sp->chap.rechallenging = false;

        switch (sp->scp[IDX_CHAP].state) {
        case STATE_REQ_SENT:
                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                cp->scr(sp);
                break;
        case STATE_OPENED:
                sppp_cp_change_state(cp, sp, STATE_ACK_SENT);
                cp->scr(sp);
                break;
        }
}

/*
 *--------------------------------------------------------------------------*
 *                                                                          *
 *                        The PAP implementation.                           *
 *                                                                          *
 *--------------------------------------------------------------------------*
 */
/*
 * PAP uses following actions and events.
 * Actions:
 *    - scr: send PAP_REQ
 *    - sca: send PAP_ACK
 *    - scn: send PAP_NAK
 * Events:
 *    - RCR+: receive PAP_REQ containing correct username and password
 *    - RCR-: receive PAP_REQ containing wrong username and password
 *    - RCA: receive PAP_ACK
 *    - RCN: (this event is unused)
 *    - TO+: re-send PAP_REQ
 *    - TO-: this layer finish
 */

/*
 * Handle incoming PAP packets.  */
static void
sppp_pap_input(struct sppp *sp, struct mbuf *m)
{
        const bool debug = sppp_debug_enabled(sp);
        struct ifnet *ifp = &sp->pp_if;
        struct lcp_header *h;
        int len;
        char *name, *secret;
        int name_len, secret_len;
        char abuf[SPPP_AUTHTYPE_NAMELEN];
        const char *authname;

        KASSERT(SPPP_WLOCKED(sp));
        /*
         * Malicious input might leave this uninitialized, so
         * init to an impossible value.
         */
        secret_len = -1;

        len = m->m_pkthdr.len;
        if (len < 5) {
                SPPP_DLOG(sp, "pap invalid packet length: "
                    "%d bytes\n", len);
                return;
        }
        h = mtod(m, struct lcp_header *);
        if (len > ntohs(h->len))
                len = ntohs(h->len);

        switch (h->type) {
        /* PAP request is my authproto */
        case PAP_REQ:
                if (sp->hisauth.name == NULL || sp->hisauth.secret == NULL) {
                        /* can't do anything useful */
                        SPPP_DLOG(sp, "pap request"
                            " without his name and his secret being set\n");
                        break;
                }
                name = 1 + (u_char *)(h + 1);
                name_len = name[-1];
                secret = name + name_len + 1;
                if (name_len > len - 6 ||
                    (secret_len = secret[-1]) > len - 6 - name_len) {
                        if (debug) {
                                authname = sppp_auth_type_name(abuf,
                                    sizeof(abuf), PPP_PAP, h->type);
                                SPPP_LOG(sp, LOG_DEBUG, "pap corrupted input "
                                    "<%s id=0x%x len=%d",
                                    authname, h->ident, ntohs(h->len));
                                if (len > 4)
                                        sppp_print_bytes((u_char *)(h + 1),
                                            len - 4);
                                addlog(">\n");
                        }
                        break;
                }
                if (debug) {
                        authname = sppp_auth_type_name(abuf,
                            sizeof(abuf), PPP_PAP, h->type);
                        SPPP_LOG(sp, LOG_DEBUG, "pap input(%s) "
                            "<%s id=0x%x len=%d name=",
                            sppp_state_name(sp->scp[IDX_PAP].state),
                            authname, h->ident, ntohs(h->len));
                        sppp_print_string((char *)name, name_len);
                        addlog(" secret=");
                        sppp_print_string((char *)secret, secret_len);
                        addlog(">\n");
                }

                sp->scp[IDX_PAP].rconfid = h->ident;

                if (name_len == sp->hisauth.name_len &&
                    memcmp(name, sp->hisauth.name, name_len) == 0 &&
                    secret_len == sp->hisauth.secret_len &&
                    memcmp(secret, sp->hisauth.secret, secret_len) == 0) {
                        sp->scp[IDX_PAP].rcr_type = CP_RCR_ACK;
                } else {
                        sp->scp[IDX_PAP].rcr_type = CP_RCR_NAK;
                }

                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_PAP].work_rcr);

                /* generate a dummy RCA event */
                if (sp->scp[IDX_PAP].rcr_type == CP_RCR_ACK &&
                    !ISSET(sppp_auth_role(&pap, sp), SPPP_AUTH_PEER)) {
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_PAP].work_rca);
                }
                break;

        /* ack and nak are his authproto */
        case PAP_ACK:
                if (debug) {
                        SPPP_LOG(sp, LOG_DEBUG, "pap success");
                        name = 1 + (u_char *)(h + 1);
                        name_len = name[-1];
                        if (len > 5 && name_len < len+4) {
                                addlog(": ");
                                sppp_print_string(name, name_len);
                        }
                        addlog("\n");
                }

                if (h->ident != sp->scp[IDX_PAP].confid) {
                        SPPP_DLOG(sp, "%s id mismatch 0x%x != 0x%x\n",
                            pap.name, h->ident, sp->scp[IDX_PAP].rconfid);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                sp->pp_auth_failures = 0;
                sp->pp_flags &= ~PP_NEEDAUTH;

                /* we are not authenticator, generate a dummy RCR+ event */
                if (!ISSET(sppp_auth_role(&pap, sp), SPPP_AUTH_SERV)) {
                        sp->scp[IDX_PAP].rcr_type = CP_RCR_ACK;
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_PAP].work_rcr);
                }

                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_PAP].work_rca);
                break;

        case PAP_NAK:
                if (debug) {
                        SPPP_LOG(sp, LOG_INFO, "pap failure");
                        name = 1 + (u_char *)(h + 1);
                        name_len = name[-1];
                        if (len > 5 && name_len < len+4) {
                                addlog(": ");
                                sppp_print_string(name, name_len);
                        }
                        addlog("\n");
                } else {
                        SPPP_LOG(sp, LOG_INFO, "pap failure\n");
                }

                if (h->ident != sp->scp[IDX_PAP].confid) {
                        SPPP_DLOG(sp, "%s id mismatch 0x%x != 0x%x\n",
                            pap.name, h->ident, sp->scp[IDX_PAP].rconfid);
                        if_statinc(ifp, if_ierrors);
                        break;
                }

                sp->pp_auth_failures++;
                /*
                 * await LCP shutdown by authenticator,
                 * so we don't have to enqueue sc->scp[IDX_PAP].work_rcn
                 */
                break;

        default:
                /* Unknown PAP packet type -- ignore. */
                if (debug) {
                        SPPP_LOG(sp, LOG_DEBUG, "pap corrupted input "
                            "<0x%x id=0x%x len=%d",
                            h->type, h->ident, ntohs(h->len));
                        if (len > 4)
                                sppp_print_bytes((u_char *)(h + 1), len - 4);
                        addlog(">\n");
                }
                break;
        }
}

static void
sppp_pap_init(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));
        sppp_cp_init(&pap, sp);
}

static void
sppp_pap_tlu(struct sppp *sp)
{

        SPPP_DLOG(sp, "%s tlu\n", pap.name);

        sp->scp[IDX_PAP].rst_counter = sp->lcp.max_configure;
        sp->pp_auth_failures = 0;

        if (sp->pp_phase < SPPP_PHASE_NETWORK)
                sppp_phase_network(sp);
}

static void
sppp_pap_scr(struct sppp *sp)
{
        u_char idlen, pwdlen;

        KASSERT(SPPP_WLOCKED(sp));

        if (ISSET(sppp_auth_role(&pap, sp), SPPP_AUTH_PEER) &&
            sp->scp[IDX_PAP].state != STATE_ACK_RCVD) {
                if (sp->myauth.secret == NULL ||
                    sp->myauth.name == NULL) {
                        SPPP_LOG(sp, LOG_DEBUG,
                            "couldn't send PAP_REQ "
                            "because of no name or no secret\n");
                } else {
                        sp->scp[IDX_PAP].confid = ++sp->scp[IDX_PAP].seq;
                        pwdlen = sp->myauth.secret_len;
                        idlen = sp->myauth.name_len;

                        sppp_auth_send(&pap, sp, PAP_REQ, sp->scp[IDX_PAP].confid,
                            sizeof idlen, (const char *)&idlen,
                            idlen, sp->myauth.name,
                            sizeof pwdlen, (const char *)&pwdlen,
                            pwdlen, sp->myauth.secret,
                            0);
                }
        }
}

/*
 * Random miscellaneous functions.
 */

/*
 * Send a PAP or CHAP proto packet.
 *
 * Variadic function, each of the elements for the ellipsis is of type
 * ``size_t mlen, const u_char *msg''.  Processing will stop iff
 * mlen == 0.
 * NOTE: never declare variadic functions with types subject to type
 * promotion (i.e. u_char). This is asking for big trouble depending
 * on the architecture you are on...
 */

static void
sppp_auth_send(const struct cp *cp, struct sppp *sp,
               unsigned int type, unsigned int id,
               ...)
{
        struct ifnet *ifp = &sp->pp_if;
        struct lcp_header *lh;
        struct mbuf *m;
        u_char *p;
        int len;
        size_t pkthdrlen;
        unsigned int mlen;
        const char *msg;
        va_list ap;

        KASSERT(SPPP_WLOCKED(sp));

        MGETHDR(m, M_DONTWAIT, MT_DATA);
        if (! m)
                return;
        m_reset_rcvif(m);

        if (ISSET(sp->pp_dev_flags, PP_DEVF_NOFRAMING)) {
                *mtod(m, uint16_t *) = htons(cp->proto);
                pkthdrlen = 2;
                lh = (struct lcp_header *)(mtod(m, uint8_t *)+2);
        } else {
                struct ppp_header *h;
                h = mtod(m, struct ppp_header *);
                h->address = PPP_ALLSTATIONS;           /* broadcast address */
                h->control = PPP_UI;                    /* Unnumbered Info */
                h->protocol = htons(cp->proto);
                pkthdrlen = PPP_HEADER_LEN;

                lh = (struct lcp_header *)(h + 1);
        }

        lh->type = type;
        lh->ident = id;
        p = (u_char *)(lh + 1);

        va_start(ap, id);
        len = 0;

        while ((mlen = (unsigned int)va_arg(ap, size_t)) != 0) {
                msg = va_arg(ap, const char *);
                len += mlen;
                if (len > MHLEN - pkthdrlen - LCP_HEADER_LEN) {
                        va_end(ap);
                        m_freem(m);
                        return;
                }

                memcpy(p, msg, mlen);
                p += mlen;
        }
        va_end(ap);

        m->m_pkthdr.len = m->m_len = pkthdrlen + LCP_HEADER_LEN + len;
        lh->len = htons(LCP_HEADER_LEN + len);

        if (sppp_debug_enabled(sp)) {
                char abuf[SPPP_AUTHTYPE_NAMELEN];
                const char *authname;

                authname = sppp_auth_type_name(abuf,
                    sizeof(abuf), cp->proto, lh->type);
                SPPP_LOG(sp, LOG_DEBUG, "%s output <%s id=0x%x len=%d",
                    cp->name, authname,
                    lh->ident, ntohs(lh->len));
                if (len)
                        sppp_print_bytes((u_char *)(lh + 1), len);
                addlog(">\n");
        }
        if (IF_QFULL(&sp->pp_cpq)) {
                IF_DROP(&sp->pp_fastq);
                IF_DROP(&ifp->if_snd);
                m_freem(m);
                return;
        }

        if_statadd(ifp, if_obytes, m->m_pkthdr.len + sp->pp_framebytes);
        IF_ENQUEUE(&sp->pp_cpq, m);

        if (! (ifp->if_flags & IFF_OACTIVE)) {
                SPPP_UNLOCK(sp);
                if_start_lock(ifp);
                SPPP_LOCK(sp, RW_WRITER);
        }
}

static int
sppp_auth_role(const struct cp *cp, struct sppp *sp)
{
        int role;

        role = SPPP_AUTH_NOROLE;

        if (sp->hisauth.proto == cp->proto &&
            ISSET(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO))
                SET(role, SPPP_AUTH_SERV);

        if (sp->myauth.proto == cp->proto)
                SET(role, SPPP_AUTH_PEER);

        return role;
}

static void
sppp_auth_to_event(struct sppp *sp, void *xcp)
{
        const struct cp *cp = xcp;
        bool override;
        int state;

        KASSERT(SPPP_WLOCKED(sp));
        KASSERT(!cpu_softintr_p());

        override = false;
        state = sp->scp[cp->protoidx].state;

        if (sp->scp[cp->protoidx].rst_counter > 0) {
                /* override TO+ event */
                switch (state) {
                case STATE_OPENED:
                        if ((sp->hisauth.flags & SPPP_AUTHFLAG_NORECHALLENGE) == 0) {
                                override = true;
                                sp->chap.rechallenging = true;
                                sp->chap.response_rcvd = false;
                                sppp_cp_change_state(cp, sp, STATE_REQ_SENT);
                                cp->scr(sp);
                        }
                        break;

                case STATE_ACK_RCVD:
                        override = true;
                        cp->scr(sp);
                        callout_schedule(&sp->scp[cp->protoidx].ch, sp->lcp.timeout);
                        break;
                }
        }

        if (override) {
                SPPP_DLOG(sp, "%s TO(%s) rst_counter = %d\n",
                    cp->name, sppp_state_name(state),
                    sp->scp[cp->protoidx].rst_counter);
                sp->scp[cp->protoidx].rst_counter--;
        } else {
                sppp_to_event(sp, xcp);
        }
}

static void
sppp_auth_screply(const struct cp *cp, struct sppp *sp, u_char ctype,
    uint8_t ident, size_t _mlen __unused, void *_msg __unused)
{
        static const char *succmsg = "Welcome!";
        static const char *failmsg = "Failed...";
        const char *msg;
        u_char type, mlen;

        KASSERT(SPPP_WLOCKED(sp));

        if (!ISSET(sppp_auth_role(cp, sp), SPPP_AUTH_SERV))
                return;

        if (ctype == CONF_ACK) {
                type = cp->proto == PPP_CHAP ? CHAP_SUCCESS : PAP_ACK;
                msg = succmsg;
                mlen = sizeof(succmsg) - 1;

                sp->pp_auth_failures = 0;
        } else {
                type = cp->proto == PPP_CHAP ? CHAP_FAILURE : PAP_NAK;
                msg = failmsg;
                mlen = sizeof(failmsg) - 1;

                /* Reset LCP if auth failed */
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_close);
                sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_open);
                sp->pp_auth_failures++;
        }

        sppp_auth_send(cp, sp, type, ident, mlen, (const u_char *)msg, 0);
}

/*
 * Send keepalive packets, every 10 seconds.
 */
static void
sppp_keepalive(void *dummy)
{
        struct sppp *sp;
        uint32_t now, last_activity, last_receive;

        SPPPQ_LOCK();

        now = time_uptime32;
        for (sp=spppq; sp; sp=sp->pp_next) {
                SPPP_LOCK(sp, RW_WRITER);
                last_activity = atomic_load_relaxed(&sp->pp_last_activity);
                last_receive = atomic_load_relaxed(&sp->pp_last_receive);

                /* check idle timeout */
                if ((sp->pp_idle_timeout != 0) && sp->pp_connecting
                    && (sp->pp_phase == SPPP_PHASE_NETWORK)) {
                    /* idle timeout is enabled for this interface */
                    if ((now - last_activity) >= sp->pp_idle_timeout) {
                        SPPP_DLOG(sp, "no activity for %lu seconds\n",
                                (unsigned long)(now - last_activity));
                        sppp_disconnect(sp);
                        SPPP_UNLOCK(sp);
                        continue;
                    }
                }

                /* Keepalive mode disabled or channel down? */
                if (! ISSET(sp->pp_dev_flags, PP_DEVF_KEEPALIVE) ||
                    ! sp->pp_connecting) {
                        SPPP_UNLOCK(sp);
                        continue;
                }

                /* No keepalive in PPP mode if LCP not opened yet. */
                if (sp->pp_phase < SPPP_PHASE_AUTHENTICATE) {
                        SPPP_UNLOCK(sp);
                        continue;
                }

                /* No echo reply, but maybe user data passed through? */
                if (sp->pp_max_noreceive != 0 &&
                    (now - last_receive) < sp->pp_max_noreceive) {
                        sp->pp_alivecnt = 0;
                        SPPP_UNLOCK(sp);
                        continue;
                }

                /* No echo request */
                if (sp->pp_alive_interval == 0) {
                        SPPP_UNLOCK(sp);
                        continue;
                }

                /* send a ECHO_REQ once in sp->pp_alive_interval times */
                if ((sppp_keepalive_cnt % sp->pp_alive_interval) != 0) {
                        SPPP_UNLOCK(sp);
                        continue;
                }

                if (sp->pp_alivecnt >= sp->pp_maxalive) {
                        /* No keepalive packets got. Stop the interface. */
                        SPPP_LOG(sp, LOG_INFO,"LCP keepalive timed out, "
                            "going to restart the connection\n");

                        sp->pp_alivecnt = 0;

                        if (sp->pp_flags & PP_IFDOWN)
                                sppp_wq_add(sp->wq_cp, &sp->work_ifdown);
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_close);
                        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_open);

                        SPPP_UNLOCK(sp);
                        continue;
                }
                if (sp->pp_alivecnt < sp->pp_maxalive)
                        ++sp->pp_alivecnt;
                if (sp->pp_phase >= SPPP_PHASE_AUTHENTICATE) {
                        int32_t nmagic = htonl(sp->lcp.magic);
                        sp->lcp.echoid = ++sp->scp[IDX_LCP].seq;
                        sppp_cp_send(sp, PPP_LCP, ECHO_REQ,
                                sp->lcp.echoid, 4, &nmagic);
                }

                SPPP_UNLOCK(sp);
        }
        sppp_keepalive_cnt++;
        callout_schedule(&keepalive_ch, hz * sppp_keepalive_interval);

        SPPPQ_UNLOCK();
}

#ifdef INET
/*
 * Get both IP addresses.
 */
static void
sppp_get_ip_addrs(struct sppp *sp, uint32_t *src, uint32_t *dst, uint32_t *srcmask)
{
        struct ifnet *ifp = &sp->pp_if;
        struct ifaddr *ifa;
        uint32_t ssrc, ddst;
        int bound;
        struct psref psref;

        ssrc = ddst = 0;
        /*
         * Pick the first AF_INET address from the list,
         * aliases don't make any sense on a p2p link anyway.
         */
        bound = curlwp_bind();
        ifa = if_first_addr_psref(ifp, AF_INET, &psref);
        if (ifa != NULL) {
                struct sockaddr_in *si = satosin(ifa->ifa_addr);
                struct sockaddr_in *sm = satosin(ifa->ifa_netmask);
                if (si->sin_addr.s_addr) {
                        ssrc = si->sin_addr.s_addr;
                        if (srcmask)
                                *srcmask = ntohl(sm->sin_addr.s_addr);
                }

                si = satosin(ifa->ifa_dstaddr);
                if (si && si->sin_addr.s_addr)
                        ddst = si->sin_addr.s_addr;
                ifa_release(ifa, &psref);
        }
        curlwp_bindx(bound);

        if (dst) *dst = ntohl(ddst);
        if (src) *src = ntohl(ssrc);
}

/*
 * Set IP addresses.
 * If an address is 0, leave it the way it is.
 */
static void
sppp_set_ip_addrs(struct sppp *sp)
{
        struct ifnet *ifp = &sp->pp_if;
        struct ifaddr *ifa;
        struct sockaddr_in *si, *dest;
        uint32_t myaddr = 0, hisaddr = 0;
        int bound;
        struct psref psref;

        KASSERT(SPPP_WLOCKED(sp));

        SPPP_UNLOCK(sp);
        IFNET_LOCK(ifp);
        SPPP_LOCK(sp, RW_WRITER);

        /*
         * Pick the first AF_INET address from the list,
         * aliases don't make any sense on a p2p link anyway.
         */
        si = dest = NULL;
        bound = curlwp_bind();
        ifa = if_first_addr_psref(ifp, AF_INET, &psref);
        if (ifa != NULL) {
                si = satosin(ifa->ifa_addr);
                dest = satosin(ifa->ifa_dstaddr);
        }

        if ((sp->ipcp.flags & IPCP_MYADDR_DYN) && (sp->ipcp.flags & IPCP_MYADDR_SEEN))
                myaddr = sp->ipcp.req_myaddr;
        else if (si != NULL)
                myaddr = ntohl(si->sin_addr.s_addr);

        if ((sp->ipcp.flags & IPCP_HISADDR_DYN) && (sp->ipcp.flags & IPCP_HISADDR_SEEN))
                hisaddr = sp->ipcp.req_hisaddr;
        else if (dest != NULL)
                hisaddr = ntohl(dest->sin_addr.s_addr);

        if (si != NULL && dest != NULL) {
                int error;
                struct sockaddr_in new_sin = *si;
                struct sockaddr_in new_dst = *dest;

                if (myaddr != 0)
                        new_sin.sin_addr.s_addr = htonl(myaddr);
                if (hisaddr != 0) {
                        new_dst.sin_addr.s_addr = htonl(hisaddr);
                        if (new_dst.sin_addr.s_addr != dest->sin_addr.s_addr)
                                sp->ipcp.saved_hisaddr = dest->sin_addr.s_addr;
                }

                in_addrhash_remove(ifatoia(ifa));

                error = in_ifinit(ifp, ifatoia(ifa), &new_sin, &new_dst, 0);

                in_addrhash_insert(ifatoia(ifa));

                if (error) {
                        SPPP_DLOG(sp, "%s: in_ifinit failed, error=%d\n",
                            __func__, error);
                } else {
                        pfil_run_addrhooks(if_pfil, SIOCAIFADDR, ifa);
                }
        }
        if (ifa != NULL)
                ifa_release(ifa, &psref);
        curlwp_bindx(bound);

        IFNET_UNLOCK(ifp);
}

/*
 * Clear IP addresses.
 */
static void
sppp_clear_ip_addrs(struct sppp *sp)
{
        struct ifnet *ifp = &sp->pp_if;
        struct ifaddr *ifa;
        struct sockaddr_in *si, *dest;
        int bound;
        struct psref psref;

        KASSERT(SPPP_WLOCKED(sp));

        SPPP_UNLOCK(sp);
        IFNET_LOCK(ifp);
        SPPP_LOCK(sp, RW_WRITER);

        /*
         * Pick the first AF_INET address from the list,
         * aliases don't make any sense on a p2p link anyway.
         */
        si = dest = NULL;
        bound = curlwp_bind();
        ifa = if_first_addr_psref(ifp, AF_INET, &psref);
        if (ifa != NULL) {
                si = satosin(ifa->ifa_addr);
                dest = satosin(ifa->ifa_dstaddr);
                /*
                 * ignore "0.0.0.0" which means ppp is not opened yet.
                 */
                if (si->sin_addr.s_addr == INADDR_ANY)
                        si = NULL;
        }

        if (si != NULL) {
                struct sockaddr_in new_sin = *si;
                struct sockaddr_in new_dst = *dest;
                int error;

                if (sp->ipcp.flags & IPCP_MYADDR_DYN)
                        new_sin.sin_addr.s_addr = 0;
                if (sp->ipcp.flags & IPCP_HISADDR_DYN &&
                    ntohl(sp->ipcp.saved_hisaddr) != 0)
                        new_dst.sin_addr.s_addr = sp->ipcp.saved_hisaddr;

                in_addrhash_remove(ifatoia(ifa));

                error = in_ifinit(ifp, ifatoia(ifa), &new_sin, &new_dst, 0);

                in_addrhash_insert(ifatoia(ifa));

                if (error) {
                        SPPP_DLOG(sp, "%s: in_ifinit failed, error=%d\n",
                            __func__, error);
                } else {
                        pfil_run_addrhooks(if_pfil, SIOCAIFADDR, ifa);
                }
        }
        if (ifa != NULL)
                ifa_release(ifa, &psref);
        curlwp_bindx(bound);

        IFNET_UNLOCK(ifp);
}
#endif

#ifdef INET6
/*
 * Get both IPv6 addresses.
 */
static void
sppp_get_ip6_addrs(struct sppp *sp, struct in6_addr *src, struct in6_addr *dst,
                   struct in6_addr *srcmask)
{
        struct ifnet *ifp = &sp->pp_if;
        struct ifaddr *ifa;
        struct in6_addr ssrc, ddst;
        int bound;
        struct psref psref;

        memset(&ssrc, 0, sizeof(ssrc));
        memset(&ddst, 0, sizeof(ddst));
        /*
         * Pick the first link-local AF_INET6 address from the list,
         * aliases don't make any sense on a p2p link anyway.
         */
        bound = curlwp_bind();
        ifa = in6ifa_first_lladdr_psref(ifp, &psref);
        if (ifa != NULL) {
                struct sockaddr_in6 *si = satosin6(ifa->ifa_addr);
                struct sockaddr_in6 *sm = satosin6(ifa->ifa_netmask);
                if (!IN6_IS_ADDR_UNSPECIFIED(&si->sin6_addr)) {
                        memcpy(&ssrc, &si->sin6_addr, sizeof(ssrc));
                        if (srcmask) {
                                memcpy(srcmask, &sm->sin6_addr,
                                    sizeof(*srcmask));
                        }
                }

                si = (struct sockaddr_in6 *)ifa->ifa_dstaddr;
                if (si && !IN6_IS_ADDR_UNSPECIFIED(&si->sin6_addr))
                        memcpy(&ddst, &si->sin6_addr, sizeof(ddst));
                ifa_release(ifa, &psref);
        }
        curlwp_bindx(bound);

        if (dst)
                memcpy(dst, &ddst, sizeof(*dst));
        if (src)
                memcpy(src, &ssrc, sizeof(*src));
}

#ifdef IPV6CP_MYIFID_DYN
/*
 * Generate random ifid.
 */
static void
sppp_gen_ip6_addr(struct sppp *sp, struct in6_addr *addr)
{
        /* TBD */
}

/*
 * Set my IPv6 address.
 */
static void
sppp_set_ip6_addr(struct sppp *sp, const struct in6_addr *src)
{
        struct ifnet *ifp = &sp->pp_if;
        struct ifaddr *ifa;
        int bound;
        struct psref psref;

        KASSERT(SPPP_WLOCKED(sp));

        SPPP_UNLOCK(sp);
        IFNET_LOCK(ifp);
        SPPP_LOCK(sp, RW_WRITER);

        /*
         * Pick the first link-local AF_INET6 address from the list,
         * aliases don't make any sense on a p2p link anyway.
         */
        bound = curlwp_bind();
        ifa = in6ifa_first_lladdr_psref(ifp, &psref);
        if (ifa != NULL) {
                struct sockaddr_in6 *sin6 = satosin6(ifa->ifa_addr);
                struct sockaddr_in6 new_sin6 = *sin6;
                int error;

                memcpy(&new_sin6.sin6_addr, src, sizeof(new_sin6.sin6_addr));
                error = in6_ifinit(ifp, ifatoia6(ifa), &new_sin6, 1);
                if (error) {
                        SPPP_DLOG(sp, "%s: in6_ifinit failed, error=%d\n",
                            __func__, error);
                } else {
                        pfil_run_addrhooks(if_pfil, SIOCAIFADDR_IN6, ifa);
                }
                ifa_release(ifa, &psref);
        }
        curlwp_bindx(bound);

        IFNET_UNLOCK(ifp);
}
#endif

/*
 * Suggest a candidate address to be used by peer.
 */
static void
sppp_suggest_ip6_addr(struct sppp *sp, struct in6_addr *suggest)
{
        struct in6_addr myaddr;
        struct timeval tv;

        sppp_get_ip6_addrs(sp, &myaddr, 0, 0);

        myaddr.s6_addr[8] &= ~0x02;     /* u bit to "local" */
        microtime(&tv);
        if ((tv.tv_usec & 0xff) == 0 && (tv.tv_sec & 0xff) == 0) {
                myaddr.s6_addr[14] ^= 0xff;
                myaddr.s6_addr[15] ^= 0xff;
        } else {
                myaddr.s6_addr[14] ^= (tv.tv_usec & 0xff);
                myaddr.s6_addr[15] ^= (tv.tv_sec & 0xff);
        }
        if (suggest)
                memcpy(suggest, &myaddr, sizeof(myaddr));
}
#endif /*INET6*/

/*
 * Process ioctl requests specific to the PPP interface.
 * Permissions have already been checked.
 */
static int
sppp_params(struct sppp *sp, u_long cmd, void *data)
{
        switch (cmd) {
        case SPPPGETAUTHCFG:
            {
                struct spppauthcfg *cfg = (struct spppauthcfg *)data;
                int error;
                size_t len;

                SPPP_LOCK(sp, RW_READER);

                cfg->myauthflags = sp->myauth.flags;
                cfg->hisauthflags = sp->hisauth.flags;
                strlcpy(cfg->ifname, sp->pp_if.if_xname, sizeof(cfg->ifname));
                cfg->hisauth = sppp_proto2authproto(sp->hisauth.proto);
                cfg->myauth = sppp_proto2authproto(sp->myauth.proto);
                if (cfg->myname_length == 0) {
                    if (sp->myauth.name != NULL)
                        cfg->myname_length = sp->myauth.name_len + 1;
                } else {
                    if (sp->myauth.name == NULL) {
                        cfg->myname_length = 0;
                    } else {
                        len = sp->myauth.name_len + 1;

                        if (cfg->myname_length < len) {
                                SPPP_UNLOCK(sp);
                                return (ENAMETOOLONG);
                        }
                        error = copyout(sp->myauth.name, cfg->myname, len);
                        if (error) {
                                SPPP_UNLOCK(sp);
                                return error;
                        }
                    }
                }
                if (cfg->hisname_length == 0) {
                    if (sp->hisauth.name != NULL)
                        cfg->hisname_length = sp->hisauth.name_len + 1;
                } else {
                    if (sp->hisauth.name == NULL) {
                        cfg->hisname_length = 0;
                    } else {
                        len = sp->hisauth.name_len + 1;

                        if (cfg->hisname_length < len) {
                                SPPP_UNLOCK(sp);
                                return (ENAMETOOLONG);
                        }
                        error = copyout(sp->hisauth.name, cfg->hisname, len);
                        if (error) {
                                SPPP_UNLOCK(sp);
                                return error;
                        }
                    }
                }
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPSETAUTHCFG:
            {
                struct spppauthcfg *cfg = (struct spppauthcfg *)data;
                int error;

                SPPP_LOCK(sp, RW_WRITER);

                if (sp->myauth.name) {
                        free(sp->myauth.name, M_DEVBUF);
                        sp->myauth.name = NULL;
                }
                if (sp->myauth.secret) {
                        free(sp->myauth.secret, M_DEVBUF);
                        sp->myauth.secret = NULL;
                }
                if (sp->hisauth.name) {
                        free(sp->hisauth.name, M_DEVBUF);
                        sp->hisauth.name = NULL;
                }
                if (sp->hisauth.secret) {
                        free(sp->hisauth.secret, M_DEVBUF);
                        sp->hisauth.secret = NULL;
                }

                if (cfg->hisname != NULL && cfg->hisname_length > 0) {
                        if (cfg->hisname_length >= MCLBYTES) {
                                SPPP_UNLOCK(sp);
                                return (ENAMETOOLONG);
                        }
                        sp->hisauth.name = malloc(cfg->hisname_length, M_DEVBUF, M_WAITOK);
                        error = copyin(cfg->hisname, sp->hisauth.name, cfg->hisname_length);
                        if (error) {
                                free(sp->hisauth.name, M_DEVBUF);
                                sp->hisauth.name = NULL;
                                SPPP_UNLOCK(sp);
                                return error;
                        }
                        sp->hisauth.name_len = cfg->hisname_length - 1;
                        sp->hisauth.name[sp->hisauth.name_len] = 0;
                }
                if (cfg->hissecret != NULL && cfg->hissecret_length > 0) {
                        if (cfg->hissecret_length >= MCLBYTES) {
                                SPPP_UNLOCK(sp);
                                return (ENAMETOOLONG);
                        }
                        sp->hisauth.secret = malloc(cfg->hissecret_length,
                            M_DEVBUF, M_WAITOK);
                        error = copyin(cfg->hissecret, sp->hisauth.secret,
                            cfg->hissecret_length);
                        if (error) {
                                free(sp->hisauth.secret, M_DEVBUF);
                                sp->hisauth.secret = NULL;
                                SPPP_UNLOCK(sp);
                                return error;
                        }
                        sp->hisauth.secret_len = cfg->hissecret_length - 1;
                        sp->hisauth.secret[sp->hisauth.secret_len] = 0;
                }
                if (cfg->myname != NULL && cfg->myname_length > 0) {
                        if (cfg->myname_length >= MCLBYTES) {
                                SPPP_UNLOCK(sp);
                                return (ENAMETOOLONG);
                        }
                        sp->myauth.name = malloc(cfg->myname_length, M_DEVBUF, M_WAITOK);
                        error = copyin(cfg->myname, sp->myauth.name, cfg->myname_length);
                        if (error) {
                                free(sp->myauth.name, M_DEVBUF);
                                sp->myauth.name = NULL;
                                SPPP_UNLOCK(sp);
                                return error;
                        }
                        sp->myauth.name_len = cfg->myname_length - 1;
                        sp->myauth.name[sp->myauth.name_len] = 0;
                }
                if (cfg->mysecret != NULL && cfg->mysecret_length > 0) {
                        if (cfg->mysecret_length >= MCLBYTES) {
                                SPPP_UNLOCK(sp);
                                return (ENAMETOOLONG);
                        }
                        sp->myauth.secret = malloc(cfg->mysecret_length,
                            M_DEVBUF, M_WAITOK);
                        error = copyin(cfg->mysecret, sp->myauth.secret,
                            cfg->mysecret_length);
                        if (error) {
                                free(sp->myauth.secret, M_DEVBUF);
                                sp->myauth.secret = NULL;
                                SPPP_UNLOCK(sp);
                                return error;
                        }
                        sp->myauth.secret_len = cfg->mysecret_length - 1;
                        sp->myauth.secret[sp->myauth.secret_len] = 0;
                }
                sp->myauth.flags = cfg->myauthflags;
                if (cfg->myauth != SPPP_AUTHPROTO_NOCHG) {
                        sp->myauth.proto = sppp_authproto2proto(cfg->myauth);
                }
                sp->hisauth.flags = cfg->hisauthflags;
                if (cfg->hisauth != SPPP_AUTHPROTO_NOCHG) {
                        sp->hisauth.proto = sppp_authproto2proto(cfg->hisauth);
                }
                sp->pp_auth_failures = 0;
                if (sp->hisauth.proto != PPP_NOPROTO)
                        SET(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO);
                else
                        CLR(sp->lcp.opts, SPPP_LCP_OPT_AUTH_PROTO);

                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETLCPCFG:
            {
                struct sppplcpcfg *lcpp = (struct sppplcpcfg *)data;

                SPPP_LOCK(sp, RW_READER);
                lcpp->lcp_timeout = sp->lcp.timeout;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPSETLCPCFG:
            {
                struct sppplcpcfg *lcpp = (struct sppplcpcfg *)data;

                SPPP_LOCK(sp, RW_WRITER);
                sp->lcp.timeout = lcpp->lcp_timeout;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETNCPCFG:
            {
                struct spppncpcfg *ncpp = (struct spppncpcfg *) data;

                SPPP_LOCK(sp, RW_READER);
                ncpp->ncp_flags = sp->pp_ncpflags;
                SPPP_UNLOCK(sp);
            }
                break;
        case SPPPSETNCPCFG:
            {
                struct spppncpcfg *ncpp = (struct spppncpcfg *) data;

                SPPP_LOCK(sp, RW_WRITER);
                sp->pp_ncpflags = ncpp->ncp_flags;
                SPPP_UNLOCK(sp);
            }
                break;
        case SPPPGETSTATUS:
            {
                struct spppstatus *status = (struct spppstatus *)data;

                SPPP_LOCK(sp, RW_READER);
                status->phase = sp->pp_phase;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETSTATUSNCP:
            {
                struct spppstatusncp *status = (struct spppstatusncp *)data;

                SPPP_LOCK(sp, RW_READER);
                status->phase = sp->pp_phase;
                status->ncpup = sppp_cp_check(sp, CP_NCP);
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETIDLETO:
            {
                struct spppidletimeout *to = (struct spppidletimeout *)data;

                SPPP_LOCK(sp, RW_READER);
                to->idle_seconds = sp->pp_idle_timeout;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPSETIDLETO:
            {
                struct spppidletimeout *to = (struct spppidletimeout *)data;

                SPPP_LOCK(sp, RW_WRITER);
                sp->pp_idle_timeout = MIN(to->idle_seconds, INT32_MAX/2);
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPSETAUTHFAILURE:
            {
                struct spppauthfailuresettings *afsettings =
                    (struct spppauthfailuresettings *)data;

                SPPP_LOCK(sp, RW_WRITER);
                sp->pp_max_auth_fail = afsettings->max_failures;
                sp->pp_auth_failures = 0;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETAUTHFAILURES:
            {
                struct spppauthfailurestats *stats = (struct spppauthfailurestats *)data;

                SPPP_LOCK(sp, RW_READER);
                stats->auth_failures = sp->pp_auth_failures;
                stats->max_failures = sp->pp_max_auth_fail;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPSETDNSOPTS:
            {
                struct spppdnssettings *req = (struct spppdnssettings *)data;

                SPPP_LOCK(sp, RW_WRITER);
                sp->query_dns = req->query_dns & 3;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETDNSOPTS:
            {
                struct spppdnssettings *req = (struct spppdnssettings *)data;

                SPPP_LOCK(sp, RW_READER);
                req->query_dns = sp->query_dns;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETDNSADDRS:
            {
                struct spppdnsaddrs *addrs = (struct spppdnsaddrs *)data;

                SPPP_LOCK(sp, RW_READER);
                memcpy(&addrs->dns, &sp->dns_addrs, sizeof addrs->dns);
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETKEEPALIVE:
            {
                struct spppkeepalivesettings *settings =
                     (struct spppkeepalivesettings*)data;

                SPPP_LOCK(sp, RW_READER);
                settings->maxalive = sp->pp_maxalive;
                settings->max_noreceive = sp->pp_max_noreceive;
                settings->alive_interval = sp->pp_alive_interval;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPSETKEEPALIVE:
            {
                struct spppkeepalivesettings *settings =
                     (struct spppkeepalivesettings*)data;

                SPPP_LOCK(sp, RW_WRITER);
                sp->pp_maxalive = settings->maxalive;
                sp->pp_max_noreceive = MIN(settings->max_noreceive,
                    INT32_MAX/2);
                sp->pp_alive_interval = settings->alive_interval;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETLCPSTATUS:
            {
                struct sppplcpstatus *status =
                    (struct sppplcpstatus *)data;

                SPPP_LOCK(sp, RW_READER);
                status->state = sp->scp[IDX_LCP].state;
                status->opts = sp->lcp.opts;
                status->magic = sp->lcp.magic;
                status->mru = sp->lcp.mru;
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETIPCPSTATUS:
            {
                struct spppipcpstatus *status =
                    (struct spppipcpstatus *)data;
                u_int32_t myaddr;

                SPPP_LOCK(sp, RW_READER);
                status->state = sp->scp[IDX_IPCP].state;
                status->opts = sp->ipcp.opts;
#ifdef INET
                sppp_get_ip_addrs(sp, &myaddr, 0, 0);
#else
                myaddr = 0;
#endif
                status->myaddr = ntohl(myaddr);
                SPPP_UNLOCK(sp);
            }
            break;
        case SPPPGETIPV6CPSTATUS:
            {
                struct spppipv6cpstatus *status =
                    (struct spppipv6cpstatus *)data;

                SPPP_LOCK(sp, RW_READER);
                status->state = sp->scp[IDX_IPV6CP].state;
                memcpy(status->my_ifid, sp->ipv6cp.my_ifid,
                    sizeof(status->my_ifid));
                memcpy(status->his_ifid, sp->ipv6cp.his_ifid,
                    sizeof(status->his_ifid));
                SPPP_UNLOCK(sp);
            }
            break;
        default:
            {
                int ret;

                MODULE_HOOK_CALL(sppp_params_50_hook, (sp, cmd, data),
                    enosys(), ret);
                if (ret != ENOSYS)
                        return ret;
                return (EINVAL);
            }
        }
        return (0);
}

static void
sppp_phase_network(struct sppp *sp)
{
        int i;

        KASSERT(SPPP_WLOCKED(sp));

        sppp_change_phase(sp, SPPP_PHASE_NETWORK);

        /* Notify NCPs now. */
        for (i = 0; i < IDX_COUNT; i++)
                if ((cps[i])->flags & CP_NCP)
                        sppp_wq_add(sp->wq_cp, &sp->scp[i].work_open);
}

static const char *
sppp_cp_type_name(char *buf, size_t buflen, u_char type)
{

        switch (type) {
        case CONF_REQ:   return "conf-req";
        case CONF_ACK:   return "conf-ack";
        case CONF_NAK:   return "conf-nak";
        case CONF_REJ:   return "conf-rej";
        case TERM_REQ:   return "term-req";
        case TERM_ACK:   return "term-ack";
        case CODE_REJ:   return "code-rej";
        case PROTO_REJ:  return "proto-rej";
        case ECHO_REQ:   return "echo-req";
        case ECHO_REPLY: return "echo-reply";
        case DISC_REQ:   return "discard-req";
        }
        if (buf != NULL)
                snprintf(buf, buflen, "0x%02x", type);
        return buf;
}

static const char *
sppp_auth_type_name(char *buf, size_t buflen, u_short proto, u_char type)
{
        const char *name;

        switch (proto) {
        case PPP_CHAP:
                switch (type) {
                case CHAP_CHALLENGE:    return "challenge";
                case CHAP_RESPONSE:     return "response";
                case CHAP_SUCCESS:      return "success";
                case CHAP_FAILURE:      return "failure";
                default:                name = "chap"; break;
                }
                break;

        case PPP_PAP:
                switch (type) {
                case PAP_REQ:           return "req";
                case PAP_ACK:           return "ack";
                case PAP_NAK:           return "nak";
                default:                name = "pap";   break;
                }
                break;

        default:
                name = "bad";
                break;
        }

        if (buf != NULL)
                snprintf(buf, buflen, "%s(%#x) 0x%02x", name, proto, type);
        return buf;
}

static const char *
sppp_lcp_opt_name(char *buf, size_t buflen, u_char opt)
{

        switch (opt) {
        case LCP_OPT_MRU:               return "mru";
        case LCP_OPT_ASYNC_MAP:         return "async-map";
        case LCP_OPT_AUTH_PROTO:        return "auth-proto";
        case LCP_OPT_QUAL_PROTO:        return "qual-proto";
        case LCP_OPT_MAGIC:             return "magic";
        case LCP_OPT_PROTO_COMP:        return "proto-comp";
        case LCP_OPT_ADDR_COMP:         return "addr-comp";
        case LCP_OPT_SELF_DESC_PAD:     return "sdpad";
        case LCP_OPT_CALL_BACK:         return "callback";
        case LCP_OPT_COMPOUND_FRMS:     return "cmpd-frms";
        case LCP_OPT_MP_MRRU:           return "mrru";
        case LCP_OPT_MP_SSNHF:          return "mp-ssnhf";
        case LCP_OPT_MP_EID:            return "mp-eid";
        }
        if (buf != NULL)
                snprintf(buf, buflen, "0x%02x", opt);
        return buf;
}

static const char *
sppp_ipcp_opt_name(char *buf, size_t buflen, u_char opt)
{

        switch (opt) {
        case IPCP_OPT_ADDRESSES:        return "addresses";
        case IPCP_OPT_COMPRESSION:      return "compression";
        case IPCP_OPT_ADDRESS:          return "address";
        case IPCP_OPT_PRIMDNS:          return "primdns";
        case IPCP_OPT_SECDNS:           return "secdns";
        }
        if (buf != NULL)
                snprintf(buf, buflen, "0x%02x", opt);
        return buf;
}

#ifdef INET6
static const char *
sppp_ipv6cp_opt_name(char *buf, size_t buflen, u_char opt)
{

        switch (opt) {
        case IPV6CP_OPT_IFID:           return "ifid";
        case IPV6CP_OPT_COMPRESSION:    return "compression";
        }
        if (buf != NULL)
                snprintf(buf, buflen, "0x%02x", opt);
        return buf;
}
#endif

static const char *
sppp_state_name(int state)
{

        switch (state) {
        case STATE_INITIAL:     return "initial";
        case STATE_STARTING:    return "starting";
        case STATE_CLOSED:      return "closed";
        case STATE_STOPPED:     return "stopped";
        case STATE_CLOSING:     return "closing";
        case STATE_STOPPING:    return "stopping";
        case STATE_REQ_SENT:    return "req-sent";
        case STATE_ACK_RCVD:    return "ack-rcvd";
        case STATE_ACK_SENT:    return "ack-sent";
        case STATE_OPENED:      return "opened";
        }
        return "illegal";
}

static const char *
sppp_phase_name(int phase)
{

        switch (phase) {
        case SPPP_PHASE_DEAD:           return "dead";
        case SPPP_PHASE_ESTABLISH:      return "establish";
        case SPPP_PHASE_TERMINATE:      return "terminate";
        case SPPP_PHASE_AUTHENTICATE:   return "authenticate";
        case SPPP_PHASE_NETWORK:        return "network";
        }
        return "illegal";
}

static const char *
sppp_proto_name(char *buf, size_t buflen, u_short proto)
{

        switch (proto) {
        case PPP_LCP:   return "lcp";
        case PPP_IPCP:  return "ipcp";
        case PPP_PAP:   return "pap";
        case PPP_CHAP:  return "chap";
        case PPP_IPV6CP: return "ipv6cp";
        }
        if (buf != NULL) {
                snprintf(buf, sizeof(buf), "0x%04x",
                    (unsigned)proto);
        }
        return buf;
}

static void
sppp_print_bytes(const u_char *p, u_short len)
{
        addlog(" %02x", *p++);
        while (--len > 0)
                addlog("-%02x", *p++);
}

static void
sppp_print_string(const char *p, u_short len)
{
        u_char c;

        while (len-- > 0) {
                c = *p++;
                /*
                 * Print only ASCII chars directly.  RFC 1994 recommends
                 * using only them, but we don't rely on it.  */
                if (c < ' ' || c > '~')
                        addlog("\\x%x", c);
                else
                        addlog("%c", c);
        }
}

static const char *
sppp_dotted_quad(char *buf, size_t buflen, uint32_t addr)
{

        if (buf != NULL) {
                snprintf(buf, buflen, "%u.%u.%u.%u",
                        (unsigned int)((addr >> 24) & 0xff),
                        (unsigned int)((addr >> 16) & 0xff),
                        (unsigned int)((addr >> 8) & 0xff),
                        (unsigned int)(addr & 0xff));
        }
        return buf;
}

/* a dummy, used to drop uninteresting events */
static void
sppp_null(struct sppp *unused)
{
        /* do just nothing */
}

static void
sppp_tls(const struct cp *cp, struct sppp *sp)
{

        SPPP_DLOG(sp, "%s tls\n", cp->name);

        /* notify lcp that is lower layer */
        sp->lcp.protos |= (1 << cp->protoidx);
}

static void
sppp_tlf(const struct cp *cp, struct sppp *sp)
{

        SPPP_DLOG(sp, "%s tlf\n", cp->name);

        /* notify lcp that is lower layer */
        sp->lcp.protos &= ~(1 << cp->protoidx);

        /* cleanup */
        m_freem(sp->scp[cp->protoidx].mbuf_confreq);
        sp->scp[cp->protoidx].mbuf_confreq = NULL;
        m_freem(sp->scp[cp->protoidx].mbuf_confnak);
        sp->scp[cp->protoidx].mbuf_confnak = NULL;

        sppp_lcp_check_and_close(sp);
}

static void
sppp_screply(const struct cp *cp, struct sppp *sp, u_char type,
    uint8_t ident, size_t msglen, void *msg)
{

        if (msglen == 0)
                return;

        switch (type) {
        case CONF_ACK:
        case CONF_NAK:
        case CONF_REJ:
                break;
        default:
                return;
        }

        if (sppp_debug_enabled(sp)) {
                char tbuf[SPPP_CPTYPE_NAMELEN];
                const char *cpname;

                cpname = sppp_cp_type_name(tbuf, sizeof(tbuf), type);
                SPPP_LOG(sp, LOG_DEBUG, "send %s\n", cpname);
        }

        sppp_cp_send(sp, cp->proto, type, ident, msglen, msg);
}

static void
sppp_ifdown(struct sppp *sp, void *xcp __unused)
{

        SPPP_UNLOCK(sp);
        if_down(&sp->pp_if);
        IF_PURGE(&sp->pp_cpq);
        SPPP_LOCK(sp, RW_WRITER);
}

static void
sppp_notify_up(struct sppp *sp)
{

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_up);
}

static void
sppp_notify_down(struct sppp *sp)
{

        sppp_wq_add(sp->wq_cp, &sp->scp[IDX_LCP].work_down);
}

static void
sppp_notify_tls_wlocked(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        if (!sp->pp_tls)
                return;

        SPPP_UNLOCK(sp);
        sp->pp_tls(sp);
        SPPP_LOCK(sp, RW_WRITER);
}

static void
sppp_notify_tlf_wlocked(struct sppp *sp)
{

        KASSERT(SPPP_WLOCKED(sp));

        if (!sp->pp_tlf)
                return;

        SPPP_UNLOCK(sp);
        sp->pp_tlf(sp);
        SPPP_LOCK(sp, RW_WRITER);
}

static void
sppp_wq_work(struct work *wk, void *xsp)
{
        struct sppp *sp;
        struct sppp_work *work;

        sp = xsp;
        work = container_of(wk, struct sppp_work, work);
        atomic_cas_uint(&work->state, SPPP_WK_BUSY, SPPP_WK_FREE);

        SPPP_LOCK(sp, RW_WRITER);
        work->func(sp, work->arg);
        SPPP_UNLOCK(sp);
}

static struct workqueue *
sppp_wq_create(struct sppp *sp, const char *xnamebuf, pri_t prio, int ipl, int flags)
{
        struct workqueue *wq;
        int error;

        error = workqueue_create(&wq, xnamebuf, sppp_wq_work,
            (void *)sp, prio, ipl, flags);
        if (error) {
                panic("%s: workqueue_create failed [%s, %d]\n",
                    sp->pp_if.if_xname, xnamebuf, error);
        }

        return wq;
}

static void
sppp_wq_destroy(struct sppp *sp __unused, struct workqueue *wq)
{

        workqueue_destroy(wq);
}

static void
sppp_wq_set(struct sppp_work *work,
    void (*func)(struct sppp *, void *), void *arg)
{

        work->func = func;
        work->arg = arg;
}

static void
sppp_wq_add(struct workqueue *wq, struct sppp_work *work)
{

        if (atomic_cas_uint(&work->state, SPPP_WK_FREE, SPPP_WK_BUSY)
            != SPPP_WK_FREE)
                return;

        KASSERT(work->func != NULL);
        kpreempt_disable();
        workqueue_enqueue(wq, &work->work, NULL);
        kpreempt_enable();
}
static void
sppp_wq_wait(struct workqueue *wq, struct sppp_work *work)
{

        atomic_swap_uint(&work->state, SPPP_WK_UNAVAIL);
        workqueue_wait(wq, &work->work);
}

/*
 * This file is large.  Tell emacs to highlight it nevertheless.
 *
 * Local Variables:
 * hilit-auto-highlight-maxout: 120000
 * End:
 */

/*
 * Module glue
 */
MODULE(MODULE_CLASS_MISC, sppp_subr, NULL);

static int
sppp_subr_modcmd(modcmd_t cmd, void *arg)
{

        switch (cmd) {
        case MODULE_CMD_INIT:
        case MODULE_CMD_FINI:
                return 0;
        case MODULE_CMD_STAT:
        case MODULE_CMD_AUTOUNLOAD:
        default:
                return ENOTTY;
        }
}