/*
 * ng_pppoe.c
 */

/*-
 * Copyright (c) 1996-1999 Whistle Communications, Inc.
 * All rights reserved.
 * 
 * Subject to the following obligations and disclaimer of warranty, use and
 * redistribution of this software, in source or object code forms, with or
 * without modifications are expressly permitted by Whistle Communications;
 * provided, however, that:
 * 1. Any and all reproductions of the source or object code must include the
 *    copyright notice above and the following disclaimer of warranties; and
 * 2. No rights are granted, in any manner or form, to use Whistle
 *    Communications, Inc. trademarks, including the mark "WHISTLE
 *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
 *    such appears in the above copyright notice or in the software.
 * 
 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * Author: Julian Elischer <julian@freebsd.org>
 * $Whistle: ng_pppoe.c,v 1.10 1999/11/01 09:24:52 julian Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/errno.h>
#include <sys/epoch.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_vlan_var.h>
#include <net/vnet.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_pppoe.h>
#include <netgraph/ng_ether.h>

#ifdef NG_SEPARATE_MALLOC
static MALLOC_DEFINE(M_NETGRAPH_PPPOE, "netgraph_pppoe", "netgraph pppoe node");
#else
#define M_NETGRAPH_PPPOE M_NETGRAPH
#endif

/* Some PPP protocol numbers we're interested in */
#define PROT_LCP                0xc021

#define SIGNOFF "session closed"

VNET_DEFINE_STATIC(u_int32_t, ng_pppoe_lcp_pcp) = 0;
#define V_ng_pppoe_lcp_pcp      VNET(ng_pppoe_lcp_pcp)

SYSCTL_NODE(_net_graph, OID_AUTO, pppoe, CTLFLAG_RW, 0, "PPPoE");
SYSCTL_UINT(_net_graph_pppoe, OID_AUTO, lcp_pcp,
        CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ng_pppoe_lcp_pcp), 0,
        "Set PCP for LCP");

/*
 * This section contains the netgraph method declarations for the
 * pppoe node. These methods define the netgraph pppoe 'type'.
 */

static ng_constructor_t ng_pppoe_constructor;
static ng_rcvmsg_t      ng_pppoe_rcvmsg;
static ng_shutdown_t    ng_pppoe_shutdown;
static ng_newhook_t     ng_pppoe_newhook;
static ng_connect_t     ng_pppoe_connect;
static ng_rcvdata_t     ng_pppoe_rcvdata;
static ng_rcvdata_t     ng_pppoe_rcvdata_ether;
static ng_rcvdata_t     ng_pppoe_rcvdata_debug;
static ng_disconnect_t  ng_pppoe_disconnect;

/* Parse type for struct ngpppoe_init_data */
static const struct ng_parse_struct_field ngpppoe_init_data_type_fields[]
        = NG_PPPOE_INIT_DATA_TYPE_INFO;
static const struct ng_parse_type ngpppoe_init_data_state_type = {
        &ng_parse_struct_type,
        &ngpppoe_init_data_type_fields
};

/* Parse type for struct ngpppoe_sts */
static const struct ng_parse_struct_field ng_pppoe_sts_type_fields[]
        = NG_PPPOE_STS_TYPE_INFO;
static const struct ng_parse_type ng_pppoe_sts_state_type = {
        &ng_parse_struct_type,
        &ng_pppoe_sts_type_fields
};

/* List of commands and how to convert arguments to/from ASCII */
static const struct ng_cmdlist ng_pppoe_cmds[] = {
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_CONNECT,
          "pppoe_connect",
          &ngpppoe_init_data_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_LISTEN,
          "pppoe_listen",
          &ngpppoe_init_data_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_OFFER,
          "pppoe_offer",
          &ngpppoe_init_data_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SERVICE,
          "pppoe_service",
          &ngpppoe_init_data_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SUCCESS,
          "pppoe_success",
          &ng_pppoe_sts_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_FAIL,
          "pppoe_fail",
          &ng_pppoe_sts_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_CLOSE,
          "pppoe_close",
          &ng_pppoe_sts_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SETMODE,
          "pppoe_setmode",
          &ng_parse_string_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_GETMODE,
          "pppoe_getmode",
          NULL,
          &ng_parse_string_type
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SETENADDR,
          "setenaddr",
          &ng_parse_enaddr_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SETMAXP,
          "setmaxp",
          &ng_parse_uint16_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SEND_HURL,
          "send_hurl",
          &ngpppoe_init_data_state_type,
          NULL
        },
        {
          NGM_PPPOE_COOKIE,
          NGM_PPPOE_SEND_MOTM,
          "send_motm",
          &ngpppoe_init_data_state_type,
          NULL
        },
        { 0 }
};

/* Netgraph node type descriptor */
static struct ng_type typestruct = {
        .version =      NG_ABI_VERSION,
        .name =         NG_PPPOE_NODE_TYPE,
        .constructor =  ng_pppoe_constructor,
        .rcvmsg =       ng_pppoe_rcvmsg,
        .shutdown =     ng_pppoe_shutdown,
        .newhook =      ng_pppoe_newhook,
        .connect =      ng_pppoe_connect,
        .rcvdata =      ng_pppoe_rcvdata,
        .disconnect =   ng_pppoe_disconnect,
        .cmdlist =      ng_pppoe_cmds,
};
NETGRAPH_INIT(pppoe, &typestruct);

/*
 * States for the session state machine.
 * These have no meaning if there is no hook attached yet.
 */
enum state {
    PPPOE_SNONE=0,      /* [both] Initial state */
    PPPOE_LISTENING,    /* [Daemon] Listening for discover initiation pkt */
    PPPOE_SINIT,        /* [Client] Sent discovery initiation */
    PPPOE_PRIMED,       /* [Server] Awaiting PADI from daemon */
    PPPOE_SOFFER,       /* [Server] Sent offer message  (got PADI)*/
    PPPOE_SREQ,         /* [Client] Sent a Request */
    PPPOE_NEWCONNECTED, /* [Server] Connection established, No data received */
    PPPOE_CONNECTED,    /* [Both] Connection established, Data received */
    PPPOE_DEAD          /* [Both] */
};

#define NUMTAGS 20 /* number of tags we are set up to work with */

/*
 * Information we store for each hook on each node for negotiating the
 * session. The mbuf and cluster are freed once negotiation has completed.
 * The whole negotiation block is then discarded.
 */

struct sess_neg {
        struct mbuf             *m; /* holds cluster with last sent packet */
        union   packet          *pkt; /* points within the above cluster */
        struct callout          handle;   /* see timeout(9) */
        u_int                   timeout; /* 0,1,2,4,8,16 etc. seconds */
        u_int                   numtags;
        const struct pppoe_tag  *tags[NUMTAGS];
        u_int                   service_len;
        u_int                   ac_name_len;
        u_int                   host_uniq_len;

        struct datatag          service;
        struct datatag          ac_name;
        struct datatag          host_uniq;
};
typedef struct sess_neg *negp;

/*
 * Session information that is needed after connection.
 */
struct sess_con {
        hook_p                  hook;
        uint16_t                Session_ID;
        enum state              state;
        ng_ID_t                 creator;        /* who to notify */
        struct pppoe_full_hdr   pkt_hdr;        /* used when connected */
        negp                    neg;            /* used when negotiating */
        LIST_ENTRY(sess_con)    sessions;
};
typedef struct sess_con *sessp;

#define SESSHASHSIZE    0x0100
#define SESSHASH(x)     (((x) ^ ((x) >> 8)) & (SESSHASHSIZE - 1))

struct sess_hash_entry {
        struct mtx      mtx;
        LIST_HEAD(hhead, sess_con) head;
};

/*
 * Information we store for each node
 */
struct PPPoE {
        node_p          node;           /* back pointer to node */
        hook_p          ethernet_hook;
        hook_p          debug_hook;
        u_int           packets_in;     /* packets in from ethernet */
        u_int           packets_out;    /* packets out towards ethernet */
        uint32_t        flags;
#define COMPAT_3COM     0x00000001
#define COMPAT_DLINK    0x00000002
        struct ether_header     eh;
        LIST_HEAD(, sess_con) listeners;
        struct sess_hash_entry  sesshash[SESSHASHSIZE];
        struct maxptag  max_payload;    /* PPP-Max-Payload (RFC4638) */
};
typedef struct PPPoE *priv_p;

union uniq {
        char bytes[sizeof(void *)];
        void *pointer;
};

#define LEAVE(x) do { error = x; goto quit; } while(0)
static void     pppoe_start(sessp sp);
static void     pppoe_ticker(node_p node, hook_p hook, void *arg1, int arg2);
static const    struct pppoe_tag *scan_tags(sessp sp,
                        const struct pppoe_hdr* ph);
static  int     pppoe_send_event(sessp sp, enum cmd cmdid);

/*************************************************************************
 * Some basic utilities  from the Linux version with author's permission.*
 * Author:      Michal Ostrowski <mostrows@styx.uwaterloo.ca>            *
 ************************************************************************/

/*
 * Return the location where the next tag can be put
 */
static __inline const struct pppoe_tag*
next_tag(const struct pppoe_hdr* ph)
{
        return (const struct pppoe_tag*)(((const char*)(ph + 1))
            + ntohs(ph->length));
}

/*
 * Look for a tag of a specific type.
 * Don't trust any length the other end says,
 * but assume we already sanity checked ph->length.
 */
static const struct pppoe_tag*
get_tag(const struct pppoe_hdr* ph, uint16_t idx)
{
        const char *const end = (const char *)next_tag(ph);
        const struct pppoe_tag *pt = (const void *)(ph + 1);
        const char *ptn;

        /*
         * Keep processing tags while a tag header will still fit.
         */
        while((const char*)(pt + 1) <= end) {
                /*
                 * If the tag data would go past the end of the packet, abort.
                 */
                ptn = (((const char *)(pt + 1)) + ntohs(pt->tag_len));
                if (ptn > end) {
                        CTR2(KTR_NET, "%20s: invalid length for tag %d",
                            __func__, idx);
                        return (NULL);
                }
                if (pt->tag_type == idx) {
                        CTR2(KTR_NET, "%20s: found tag %d", __func__, idx);
                        return (pt);
                }

                pt = (const struct pppoe_tag*)ptn;
        }

        CTR2(KTR_NET, "%20s: not found tag %d", __func__, idx);
        return (NULL);
}

/**************************************************************************
 * Inlines to initialise or add tags to a session's tag list.
 **************************************************************************/
/*
 * Initialise the session's tag list.
 */
static void
init_tags(sessp sp)
{
        KASSERT(sp->neg != NULL, ("%s: no neg", __func__));
        sp->neg->numtags = 0;
}

static void
insert_tag(sessp sp, const struct pppoe_tag *tp)
{
        negp neg = sp->neg;
        int i;

        KASSERT(neg != NULL, ("%s: no neg", __func__));
        if ((i = neg->numtags++) < NUMTAGS) {
                neg->tags[i] = tp;
        } else {
                log(LOG_NOTICE, "ng_pppoe: asked to add too many tags to "
                    "packet\n");
                neg->numtags--;
        }
}

/*
 * Make up a packet, using the tags filled out for the session.
 *
 * Assume that the actual pppoe header and ethernet header
 * are filled out externally to this routine.
 * Also assume that neg->wh points to the correct
 * location at the front of the buffer space.
 */
static void
make_packet(sessp sp) {
        struct pppoe_full_hdr *wh = &sp->neg->pkt->pkt_header;
        const struct pppoe_tag **tag;
        char *dp;
        int count;
        int tlen;
        uint16_t length = 0;

        KASSERT((sp->neg != NULL) && (sp->neg->m != NULL),
            ("%s: called from wrong state", __func__));
        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        dp = (char *)(&wh->ph + 1);
        for (count = 0, tag = sp->neg->tags;
            ((count < sp->neg->numtags) && (count < NUMTAGS));
            tag++, count++) {
                tlen = ntohs((*tag)->tag_len) + sizeof(**tag);
                if ((length + tlen) > (ETHER_MAX_LEN - 4 - sizeof(*wh))) {
                        log(LOG_NOTICE, "ng_pppoe: tags too long\n");
                        sp->neg->numtags = count;
                        break;  /* XXX chop off what's too long */
                }
                bcopy(*tag, (char *)dp, tlen);
                length += tlen;
                dp += tlen;
        }
        wh->ph.length = htons(length);
        sp->neg->m->m_len = length + sizeof(*wh);
        sp->neg->m->m_pkthdr.len = length + sizeof(*wh);
}

/**************************************************************************
 * Routines to match a service.                                           *
 **************************************************************************/

/*
 * Find a hook that has a service string that matches that
 * we are seeking. For now use a simple string.
 * In the future we may need something like regexp().
 *
 * Null string is a wildcard (ANY service), according to RFC2516.
 * And historical FreeBSD wildcard is also "*".
 */

static hook_p
pppoe_match_svc(node_p node, const struct pppoe_tag *tag)
{
        const priv_p privp = NG_NODE_PRIVATE(node);
        sessp sp;

        LIST_FOREACH(sp, &privp->listeners, sessions) {
                negp neg = sp->neg;

                /* Empty Service-Name matches any service. */
                if (neg->service_len == 0)
                        break;

                /* Special case for a blank or "*" service name (wildcard). */
                if (neg->service_len == 1 && neg->service.data[0] == '*')
                        break;

                /* If the lengths don't match, that aint it. */
                if (neg->service_len != ntohs(tag->tag_len))
                        continue;

                if (strncmp((const char *)(tag + 1), neg->service.data,
                    ntohs(tag->tag_len)) == 0)
                        break;
        }
        CTR3(KTR_NET, "%20s: matched %p for %s", __func__,
            sp?sp->hook:NULL, (const char *)(tag + 1));

        return (sp?sp->hook:NULL);
}

/*
 * Broadcast the PADI packet in m0 to all listening hooks.
 * This routine is called when a PADI with empty Service-Name
 * tag is received. Client should receive PADOs with all
 * available services.
 */
static int
pppoe_broadcast_padi(node_p node, struct mbuf *m0)
{
        const priv_p privp = NG_NODE_PRIVATE(node);
        sessp sp;
        int error = 0;

        LIST_FOREACH(sp, &privp->listeners, sessions) {
                struct mbuf *m;

                m = m_dup(m0, M_NOWAIT);
                if (m == NULL)
                        return (ENOMEM);
                NG_SEND_DATA_ONLY(error, sp->hook, m);
                if (error)
                        return (error);
        }

        return (0);
}

/*
 * Find a hook, which name equals to given service.
 */
static hook_p
pppoe_find_svc(node_p node, const char *svc_name, int svc_len)
{
        const priv_p privp = NG_NODE_PRIVATE(node);
        sessp sp;

        LIST_FOREACH(sp, &privp->listeners, sessions) {
                negp neg = sp->neg;

                if (neg->service_len == svc_len &&
                    strncmp(svc_name, neg->service.data, svc_len) == 0)
                        return (sp->hook);
        }

        return (NULL);
}

/**************************************************************************
 * Routines to find a particular session that matches an incoming packet. *
 **************************************************************************/
/* Find free session and add to hash. */
static uint16_t
pppoe_getnewsession(sessp sp)
{
        const priv_p privp = NG_NODE_PRIVATE(NG_HOOK_NODE(sp->hook));
        static uint16_t pppoe_sid = 1;
        sessp   tsp;
        uint16_t val, hash;

restart:
        /* Atomicity is not needed here as value will be checked. */
        val = pppoe_sid++;
        /* Spec says 0xFFFF is reserved, also don't use 0x0000. */
        if (val == 0xffff || val == 0x0000)
                val = pppoe_sid = 1;

        /* Check it isn't already in use. */
        hash = SESSHASH(val);
        mtx_lock(&privp->sesshash[hash].mtx);
        LIST_FOREACH(tsp, &privp->sesshash[hash].head, sessions) {
                if (tsp->Session_ID == val)
                        break;
        }
        if (!tsp) {
                sp->Session_ID = val;
                LIST_INSERT_HEAD(&privp->sesshash[hash].head, sp, sessions);
        }
        mtx_unlock(&privp->sesshash[hash].mtx);
        if (tsp)
                goto restart;

        CTR2(KTR_NET, "%20s: new sid %d", __func__, val);

        return (val);
}

/* Add specified session to hash. */
static void
pppoe_addsession(sessp sp)
{
        const priv_p    privp = NG_NODE_PRIVATE(NG_HOOK_NODE(sp->hook));
        uint16_t        hash = SESSHASH(sp->Session_ID);

        mtx_lock(&privp->sesshash[hash].mtx);
        LIST_INSERT_HEAD(&privp->sesshash[hash].head, sp, sessions);
        mtx_unlock(&privp->sesshash[hash].mtx);
}

/* Delete specified session from hash. */
static void
pppoe_delsession(sessp sp)
{
        const priv_p    privp = NG_NODE_PRIVATE(NG_HOOK_NODE(sp->hook));
        uint16_t        hash = SESSHASH(sp->Session_ID);

        mtx_lock(&privp->sesshash[hash].mtx);
        LIST_REMOVE(sp, sessions);
        mtx_unlock(&privp->sesshash[hash].mtx);
}

/* Find matching peer/session combination. */
static sessp
pppoe_findsession(priv_p privp, const struct pppoe_full_hdr *wh)
{
        uint16_t        session = ntohs(wh->ph.sid);
        uint16_t        hash = SESSHASH(session);
        sessp           sp = NULL;

        mtx_lock(&privp->sesshash[hash].mtx);
        LIST_FOREACH(sp, &privp->sesshash[hash].head, sessions) {
                if (sp->Session_ID == session &&
                    bcmp(sp->pkt_hdr.eh.ether_dhost,
                     wh->eh.ether_shost, ETHER_ADDR_LEN) == 0) {
                        break;
                }
        }
        mtx_unlock(&privp->sesshash[hash].mtx);
        CTR3(KTR_NET, "%20s: matched %p for %d", __func__, sp?sp->hook:NULL,
            session);

        return (sp);
}

static hook_p
pppoe_finduniq(node_p node, const struct pppoe_tag *tag)
{
        hook_p  hook = NULL;
        sessp   sp;

        /* Cycle through all known hooks. */
        LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
                /* Skip any nonsession hook. */
                if (NG_HOOK_PRIVATE(hook) == NULL)
                        continue;
                sp = NG_HOOK_PRIVATE(hook);
                /* Skip already connected sessions. */
                if (sp->neg == NULL)
                        continue;
                if (sp->neg->host_uniq_len == ntohs(tag->tag_len) &&
                    bcmp(sp->neg->host_uniq.data, (const char *)(tag + 1),
                     sp->neg->host_uniq_len) == 0)
                        break;
        }
        CTR3(KTR_NET, "%20s: matched %p for %p", __func__, hook, sp);

        return (hook);
}

static hook_p
pppoe_findcookie(node_p node, const struct pppoe_tag *tag)
{
        hook_p  hook = NULL;
        union uniq cookie;

        bcopy(tag + 1, cookie.bytes, sizeof(void *));
        /* Cycle through all known hooks. */
        LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
                /* Skip any nonsession hook. */
                if (NG_HOOK_PRIVATE(hook) == NULL)
                        continue;
                if (cookie.pointer == NG_HOOK_PRIVATE(hook))
                        break;
        }
        CTR3(KTR_NET, "%20s: matched %p for %p", __func__, hook, cookie.pointer);

        return (hook);
}

/**************************************************************************
 * Start of Netgraph entrypoints.                                         *
 **************************************************************************/

/*
 * Allocate the private data structure and link it with node.
 */
static int
ng_pppoe_constructor(node_p node)
{
        priv_p  privp;
        int     i;

        /* Initialize private descriptor. */
        privp = malloc(sizeof(*privp), M_NETGRAPH_PPPOE, M_WAITOK | M_ZERO);

        /* Link structs together; this counts as our one reference to *node. */
        NG_NODE_SET_PRIVATE(node, privp);
        privp->node = node;

        /* Initialize to standard mode. */
        memset(&privp->eh.ether_dhost, 0xff, ETHER_ADDR_LEN);
        privp->eh.ether_type = ETHERTYPE_PPPOE_DISC;

        LIST_INIT(&privp->listeners);
        for (i = 0; i < SESSHASHSIZE; i++) {
            mtx_init(&privp->sesshash[i].mtx, "PPPoE hash mutex", NULL, MTX_DEF);
            LIST_INIT(&privp->sesshash[i].head);
        }

        CTR3(KTR_NET, "%20s: created node [%x] (%p)",
            __func__, node->nd_ID, node);

        return (0);
}

/*
 * Give our ok for a hook to be added...
 * point the hook's private info to the hook structure.
 *
 * The following hook names are special:
 *  "ethernet":  the hook that should be connected to a NIC.
 *  "debug":    copies of data sent out here  (when I write the code).
 * All other hook names need only be unique. (the framework checks this).
 */
static int
ng_pppoe_newhook(node_p node, hook_p hook, const char *name)
{
        const priv_p privp = NG_NODE_PRIVATE(node);
        sessp sp;

        if (strcmp(name, NG_PPPOE_HOOK_ETHERNET) == 0) {
                privp->ethernet_hook = hook;
                NG_HOOK_SET_RCVDATA(hook, ng_pppoe_rcvdata_ether);
        } else if (strcmp(name, NG_PPPOE_HOOK_DEBUG) == 0) {
                privp->debug_hook = hook;
                NG_HOOK_SET_RCVDATA(hook, ng_pppoe_rcvdata_debug);
        } else {
                /*
                 * Any other unique name is OK.
                 * The infrastructure has already checked that it's unique,
                 * so just allocate it and hook it in.
                 */
                sp = malloc(sizeof(*sp), M_NETGRAPH_PPPOE, M_NOWAIT | M_ZERO);
                if (sp == NULL)
                        return (ENOMEM);

                NG_HOOK_SET_PRIVATE(hook, sp);
                sp->hook = hook;
        }
        CTR5(KTR_NET, "%20s: node [%x] (%p) connected hook %s (%p)",
            __func__, node->nd_ID, node, name, hook);

        return(0);
}

/*
 * Hook has been added successfully. Request the MAC address of
 * the underlying Ethernet node.
 */
static int
ng_pppoe_connect(hook_p hook)
{
        const priv_p privp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        struct ng_mesg *msg;
        int error;

        if (hook != privp->ethernet_hook)
                return (0);

        /*
         * If this is Ethernet hook, then request MAC address
         * from our downstream.
         */
        NG_MKMESSAGE(msg, NGM_ETHER_COOKIE, NGM_ETHER_GET_ENADDR, 0, M_NOWAIT);
        if (msg == NULL)
                return (ENOBUFS);

        /*
         * Our hook and peer hook have HK_INVALID flag set,
         * so we can't use NG_SEND_MSG_HOOK() macro here.
         */
        NG_SEND_MSG_ID(error, privp->node, msg,
            NG_NODE_ID(NG_PEER_NODE(privp->ethernet_hook)),
            NG_NODE_ID(privp->node));

        return (error);
}
/*
 * Get a netgraph control message.
 * Check it is one we understand. If needed, send a response.
 * We sometimes save the address for an async action later.
 * Always free the message.
 */
static int
ng_pppoe_rcvmsg(node_p node, item_p item, hook_p lasthook)
{
        struct epoch_tracker et;
        priv_p privp = NG_NODE_PRIVATE(node);
        struct ngpppoe_init_data *ourmsg = NULL;
        struct ng_mesg *resp = NULL;
        int error = 0;
        hook_p hook = NULL;
        sessp sp = NULL;
        negp neg = NULL;
        struct ng_mesg *msg;

        NGI_GET_MSG(item, msg);
        CTR5(KTR_NET, "%20s: node [%x] (%p) got message %d with cookie %d",
            __func__, node->nd_ID, node, msg->header.cmd,
            msg->header.typecookie);

        /* Deal with message according to cookie and command. */
        switch (msg->header.typecookie) {
        case NGM_PPPOE_COOKIE:
                switch (msg->header.cmd) {
                case NGM_PPPOE_CONNECT:
                case NGM_PPPOE_LISTEN:
                case NGM_PPPOE_OFFER:
                case NGM_PPPOE_SERVICE:
                case NGM_PPPOE_SEND_HURL:
                case NGM_PPPOE_SEND_MOTM:
                        ourmsg = (struct ngpppoe_init_data *)msg->data;
                        if (msg->header.arglen < sizeof(*ourmsg)) {
                                log(LOG_ERR, "ng_pppoe[%x]: init data too "
                                    "small\n", node->nd_ID);
                                LEAVE(EMSGSIZE);
                        }
                        if (msg->header.cmd == NGM_PPPOE_SEND_HURL ||
                            msg->header.cmd == NGM_PPPOE_SEND_MOTM) {
                                if (msg->header.arglen - sizeof(*ourmsg) >
                                    PPPOE_PADM_VALUE_SIZE) {
                                        log(LOG_ERR, "ng_pppoe[%x]: message "
                                            "too big\n", node->nd_ID);
                                        LEAVE(EMSGSIZE);
                                }
                        } else {
                                if (msg->header.arglen - sizeof(*ourmsg) >
                                    PPPOE_SERVICE_NAME_SIZE) {
                                        log(LOG_ERR, "ng_pppoe[%x]: service name "
                                            "too big\n", node->nd_ID);
                                        LEAVE(EMSGSIZE);
                                }
                        }
                        if (msg->header.arglen - sizeof(*ourmsg) <
                            ourmsg->data_len) {
                                log(LOG_ERR, "ng_pppoe[%x]: init data has bad "
                                    "length, %d should be %zd\n", node->nd_ID,
                                    ourmsg->data_len,
                                    msg->header.arglen - sizeof (*ourmsg));
                                LEAVE(EMSGSIZE);
                        }

                        /* Make sure strcmp will terminate safely. */
                        ourmsg->hook[sizeof(ourmsg->hook) - 1] = '\0';

                        /* Find hook by name. */
                        hook = ng_findhook(node, ourmsg->hook);
                        if (hook == NULL)
                                LEAVE(ENOENT);

                        sp = NG_HOOK_PRIVATE(hook);
                        if (sp == NULL)
                                LEAVE(EINVAL);

                        if (msg->header.cmd == NGM_PPPOE_LISTEN) {
                                /*
                                 * Ensure we aren't already listening for this
                                 * service.
                                 */
                                if (pppoe_find_svc(node, ourmsg->data,
                                    ourmsg->data_len) != NULL)
                                        LEAVE(EEXIST);
                        }

                        /*
                         * PPPOE_SERVICE advertisements are set up
                         * on sessions that are in PRIMED state.
                         */
                        if (msg->header.cmd == NGM_PPPOE_SERVICE)
                                break;

                        /*
                         * PADM messages are set up on active sessions.
                         */
                        if (msg->header.cmd == NGM_PPPOE_SEND_HURL ||
                            msg->header.cmd == NGM_PPPOE_SEND_MOTM) {
                                if (sp->state != PPPOE_NEWCONNECTED &&
                                    sp->state != PPPOE_CONNECTED) {
                                        log(LOG_NOTICE, "ng_pppoe[%x]: session is not "
                                            "active\n", node->nd_ID);
                                        LEAVE(EISCONN);
                                }
                                break;
                        }

                        if (sp->state != PPPOE_SNONE) {
                                log(LOG_NOTICE, "ng_pppoe[%x]: Session already "
                                    "active\n", node->nd_ID);
                                LEAVE(EISCONN);
                        }

                        /*
                         * Set up prototype header.
                         */
                        neg = malloc(sizeof(*neg), M_NETGRAPH_PPPOE,
                            M_NOWAIT | M_ZERO);

                        if (neg == NULL)
                                LEAVE(ENOMEM);

                        neg->m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
                        if (neg->m == NULL) {
                                free(neg, M_NETGRAPH_PPPOE);
                                LEAVE(ENOBUFS);
                        }
                        neg->m->m_pkthdr.rcvif = NULL;
                        sp->neg = neg;
                        ng_callout_init(&neg->handle);
                        neg->m->m_len = sizeof(struct pppoe_full_hdr);
                        neg->pkt = mtod(neg->m, union packet*);
                        memcpy((void *)&neg->pkt->pkt_header.eh,
                            &privp->eh, sizeof(struct ether_header));
                        neg->pkt->pkt_header.ph.ver = 0x1;
                        neg->pkt->pkt_header.ph.type = 0x1;
                        neg->pkt->pkt_header.ph.sid = 0x0000;
                        neg->timeout = 0;

                        sp->creator = NGI_RETADDR(item);
                }
                switch (msg->header.cmd) {
                case NGM_PPPOE_GET_STATUS:
                    {
                        struct ngpppoestat *stats;

                        NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
                        if (!resp)
                                LEAVE(ENOMEM);

                        stats = (struct ngpppoestat *) resp->data;
                        stats->packets_in = privp->packets_in;
                        stats->packets_out = privp->packets_out;
                        break;
                    }
                case NGM_PPPOE_CONNECT:
                    {
                        /*
                         * Check the hook exists and is Uninitialised.
                         * Send a PADI request, and start the timeout logic.
                         * Store the originator of this message so we can send
                         * a success or fail message to them later.
                         * Move the session to SINIT.
                         * Set up the session to the correct state and
                         * start it.
                         */
                        int     acnpos, acnlen = 0, acnsep = 0;
                        int     hupos, hulen = 0, husep = 0;
                        int     i, srvpos, srvlen;
                        acnpos = 0;
                        for (i = 0; i < ourmsg->data_len; i++) {
                                if (ourmsg->data[i] == '\\') {
                                        acnlen = i;
                                        acnsep = 1;
                                        break;
                                }
                        }
                        hupos = acnlen + acnsep;
                        for (i = hupos; i < ourmsg->data_len; i++) {
                                if (ourmsg->data[i] == '|') {
                                        hulen = i - hupos;
                                        husep = 1;
                                        break;
                                }
                        }
                        srvpos = hupos + hulen + husep;
                        srvlen = ourmsg->data_len - srvpos;

                        bcopy(ourmsg->data + acnpos, neg->ac_name.data, acnlen);
                        neg->ac_name_len = acnlen;

                        neg->host_uniq.hdr.tag_type = PTT_HOST_UNIQ;
                        if (hulen == 0) {
                                /* Not provided, generate one */
                                neg->host_uniq.hdr.tag_len = htons(sizeof(sp));
                                bcopy(&sp, neg->host_uniq.data, sizeof(sp));
                                neg->host_uniq_len = sizeof(sp);
                        } else if (hulen > 2 && ourmsg->data[hupos] == '0' &&
                          ourmsg->data[hupos + 1] == 'x' && hulen % 2 == 0) {
                                /* Hex encoded */
                                static const char hexdig[16] = "0123456789abcdef";
                                int j;

                                neg->host_uniq.hdr.tag_len = htons((uint16_t)(hulen / 2 - 1));
                                for (i = 0; i < hulen - 2; i++) {
                                        for (j = 0;
                                             j < 16 &&
                                             ourmsg->data[hupos + 2 + i] != hexdig[j];
                                             j++);
                                        if (j == 16)
                                                LEAVE(EINVAL);
                                        if (i % 2 == 0)
                                                neg->host_uniq.data[i / 2] = j << 4;
                                        else
                                                neg->host_uniq.data[i / 2] |= j;
                                }
                                neg->host_uniq_len = hulen / 2 - 1;
                        } else {
                                /* Plain string */
                                neg->host_uniq.hdr.tag_len = htons((uint16_t)hulen);
                                bcopy(ourmsg->data + hupos, neg->host_uniq.data, hulen);
                                neg->host_uniq_len = hulen;
                        }

                        neg->service.hdr.tag_type = PTT_SRV_NAME;
                        neg->service.hdr.tag_len = htons((uint16_t)srvlen);
                        bcopy(ourmsg->data + srvpos, neg->service.data, srvlen);
                        neg->service_len = srvlen;
                        NET_EPOCH_ENTER(et);
                        pppoe_start(sp);
                        NET_EPOCH_EXIT(et);
                        break;
                    }
                case NGM_PPPOE_LISTEN:
                        /*
                         * Check the hook exists and is Uninitialised.
                         * Install the service matching string.
                         * Store the originator of this message so we can send
                         * a success or fail message to them later.
                         * Move the hook to 'LISTENING'
                         */
                        neg->service.hdr.tag_type = PTT_SRV_NAME;
                        neg->service.hdr.tag_len =
                            htons((uint16_t)ourmsg->data_len);

                        if (ourmsg->data_len)
                                bcopy(ourmsg->data, neg->service.data,
                                    ourmsg->data_len);
                        neg->service_len = ourmsg->data_len;
                        neg->pkt->pkt_header.ph.code = PADT_CODE;
                        /*
                         * Wait for PADI packet coming from Ethernet.
                         */
                        sp->state = PPPOE_LISTENING;
                        LIST_INSERT_HEAD(&privp->listeners, sp, sessions);
                        break;
                case NGM_PPPOE_OFFER:
                        /*
                         * Check the hook exists and is Uninitialised.
                         * Store the originator of this message so we can send
                         * a success of fail message to them later.
                         * Store the AC-Name given and go to PRIMED.
                         */
                        neg->ac_name.hdr.tag_type = PTT_AC_NAME;
                        neg->ac_name.hdr.tag_len =
                            htons((uint16_t)ourmsg->data_len);
                        if (ourmsg->data_len)
                                bcopy(ourmsg->data, neg->ac_name.data,
                                    ourmsg->data_len);
                        neg->ac_name_len = ourmsg->data_len;
                        neg->pkt->pkt_header.ph.code = PADO_CODE;
                        /*
                         * Wait for PADI packet coming from hook.
                         */
                        sp->state = PPPOE_PRIMED;
                        break;
                case NGM_PPPOE_SERVICE:
                        /*
                         * Check the session is primed.
                         * for now just allow ONE service to be advertised.
                         * If you do it twice you just overwrite.
                         */
                        if (sp->state != PPPOE_PRIMED) {
                                log(LOG_NOTICE, "ng_pppoe[%x]: session not "
                                    "primed\n", node->nd_ID);
                                LEAVE(EISCONN);
                        }
                        neg = sp->neg;
                        neg->service.hdr.tag_type = PTT_SRV_NAME;
                        neg->service.hdr.tag_len =
                            htons((uint16_t)ourmsg->data_len);

                        if (ourmsg->data_len)
                                bcopy(ourmsg->data, neg->service.data,
                                    ourmsg->data_len);
                        neg->service_len = ourmsg->data_len;
                        break;
                case NGM_PPPOE_SETMODE:
                    {
                        char *s;
                        size_t len;

                        if (msg->header.arglen == 0)
                                LEAVE(EINVAL);

                        s = (char *)msg->data;
                        len = msg->header.arglen - 1;

                        /* Search for matching mode string. */
                        if (len == strlen(NG_PPPOE_STANDARD) &&
                            (strncmp(NG_PPPOE_STANDARD, s, len) == 0)) {
                                privp->flags = 0;
                                privp->eh.ether_type = ETHERTYPE_PPPOE_DISC;
                                break;
                        }
                        if (len == strlen(NG_PPPOE_3COM) &&
                            (strncmp(NG_PPPOE_3COM, s, len) == 0)) {
                                privp->flags |= COMPAT_3COM;
                                privp->eh.ether_type =
                                    ETHERTYPE_PPPOE_3COM_DISC;
                                break;
                        }
                        if (len == strlen(NG_PPPOE_DLINK) &&
                            (strncmp(NG_PPPOE_DLINK, s, len) == 0)) {
                                privp->flags |= COMPAT_DLINK;
                                break;
                        }
                        error = EINVAL;
                        break;
                    }
                case NGM_PPPOE_GETMODE:
                    {
                        char *s;
                        size_t len = 0;

                        if (privp->flags == 0)
                                len += strlen(NG_PPPOE_STANDARD) + 1;
                        if (privp->flags & COMPAT_3COM)
                                len += strlen(NG_PPPOE_3COM) + 1;
                        if (privp->flags & COMPAT_DLINK)
                                len += strlen(NG_PPPOE_DLINK) + 1;

                        NG_MKRESPONSE(resp, msg, len, M_NOWAIT);
                        if (resp == NULL)
                                LEAVE(ENOMEM);

                        s = (char *)resp->data;
                        if (privp->flags == 0) {
                                len = strlen(NG_PPPOE_STANDARD);
                                strlcpy(s, NG_PPPOE_STANDARD, len + 1);
                                break;
                        }
                        if (privp->flags & COMPAT_3COM) {
                                len = strlen(NG_PPPOE_3COM);
                                strlcpy(s, NG_PPPOE_3COM, len + 1);
                                s += len;
                        }
                        if (privp->flags & COMPAT_DLINK) {
                                if (s != resp->data)
                                        *s++ = '|';
                                len = strlen(NG_PPPOE_DLINK);
                                strlcpy(s, NG_PPPOE_DLINK, len + 1);
                        }
                        break;
                    }
                case NGM_PPPOE_SETENADDR:
                        if (msg->header.arglen != ETHER_ADDR_LEN)
                                LEAVE(EINVAL);
                        bcopy(msg->data, &privp->eh.ether_shost,
                            ETHER_ADDR_LEN);
                        break;
                case NGM_PPPOE_SETMAXP:
                        if (msg->header.arglen != sizeof(uint16_t))
                                LEAVE(EINVAL);
                        privp->max_payload.hdr.tag_type = PTT_MAX_PAYL;
                        privp->max_payload.hdr.tag_len = htons(sizeof(uint16_t));
                        privp->max_payload.data = htons(*((uint16_t *)msg->data));
                        break;
                case NGM_PPPOE_SEND_HURL:
                    {
                        struct mbuf *m;

                        /* Generate a packet of that type. */
                        m = m_gethdr(M_NOWAIT, MT_DATA);
                        if (m == NULL)
                                log(LOG_NOTICE, "ng_pppoe[%x]: session out of "
                                    "mbufs\n", node->nd_ID);
                        else {
                                struct pppoe_full_hdr *wh;
                                struct pppoe_tag *tag;
                                int     error = 0;

                                wh = mtod(m, struct pppoe_full_hdr *);
                                bcopy(&sp->pkt_hdr, wh, sizeof(*wh));

                                /* Revert the stored header to DISC/PADM mode. */
                                wh->ph.code = PADM_CODE;
                                /*
                                 * Configure ethertype depending on what
                                 * was used during sessions stage.
                                 */
                                if (wh->eh.ether_type ==
                                    ETHERTYPE_PPPOE_3COM_SESS)
                                        wh->eh.ether_type = ETHERTYPE_PPPOE_3COM_DISC;
                                else
                                        wh->eh.ether_type = ETHERTYPE_PPPOE_DISC;
                                /*
                                 * Add PADM message and adjust sizes.
                                 */
                                tag = (void *)(&wh->ph + 1);
                                tag->tag_type = PTT_HURL;
                                tag->tag_len = htons(ourmsg->data_len);
                                strncpy((char *)(tag + 1), ourmsg->data, ourmsg->data_len);
                                m->m_pkthdr.len = m->m_len = sizeof(*wh) + sizeof(*tag) +
                                    ourmsg->data_len;
                                wh->ph.length = htons(sizeof(*tag) + ourmsg->data_len);
                                NET_EPOCH_ENTER(et);
                                NG_SEND_DATA_ONLY(error,
                                    privp->ethernet_hook, m);
                                NET_EPOCH_EXIT(et);
                        }
                        break;
                    }
                case NGM_PPPOE_SEND_MOTM:
                    {
                        struct mbuf *m;

                        /* Generate a packet of that type. */
                        m = m_gethdr(M_NOWAIT, MT_DATA);
                        if (m == NULL)
                                log(LOG_NOTICE, "ng_pppoe[%x]: session out of "
                                    "mbufs\n", node->nd_ID);
                        else {
                                struct pppoe_full_hdr *wh;
                                struct pppoe_tag *tag;
                                int     error = 0;

                                wh = mtod(m, struct pppoe_full_hdr *);
                                bcopy(&sp->pkt_hdr, wh, sizeof(*wh));

                                /* Revert the stored header to DISC/PADM mode. */
                                wh->ph.code = PADM_CODE;
                                /*
                                 * Configure ethertype depending on what
                                 * was used during sessions stage.
                                 */
                                if (wh->eh.ether_type ==
                                    ETHERTYPE_PPPOE_3COM_SESS)
                                        wh->eh.ether_type = ETHERTYPE_PPPOE_3COM_DISC;
                                else
                                        wh->eh.ether_type = ETHERTYPE_PPPOE_DISC;
                                /*
                                 * Add PADM message and adjust sizes.
                                 */
                                tag = (void *)(&wh->ph + 1);
                                tag->tag_type = PTT_MOTM;
                                tag->tag_len = htons(ourmsg->data_len);
                                strncpy((char *)(tag + 1), ourmsg->data, ourmsg->data_len);
                                m->m_pkthdr.len = m->m_len = sizeof(*wh) + sizeof(*tag) +
                                    ourmsg->data_len;
                                wh->ph.length = htons(sizeof(*tag) + ourmsg->data_len);
                                NET_EPOCH_ENTER(et);
                                NG_SEND_DATA_ONLY(error,
                                    privp->ethernet_hook, m);
                                NET_EPOCH_EXIT(et);
                        }
                        break;
                    }
                default:
                        LEAVE(EINVAL);
                }
                break;
        case NGM_ETHER_COOKIE:
                if (!(msg->header.flags & NGF_RESP))
                        LEAVE(EINVAL);
                switch (msg->header.cmd) {
                case NGM_ETHER_GET_ENADDR:
                        if (msg->header.arglen != ETHER_ADDR_LEN)
                                LEAVE(EINVAL);
                        bcopy(msg->data, &privp->eh.ether_shost,
                            ETHER_ADDR_LEN);
                        break;
                default:
                        LEAVE(EINVAL);
                }
                break;
        default:
                LEAVE(EINVAL);
        }

        /* Take care of synchronous response, if any. */
quit:
        CTR2(KTR_NET, "%20s: returning %d", __func__, error);
        NG_RESPOND_MSG(error, node, item, resp);
        /* Free the message and return. */
        NG_FREE_MSG(msg);
        return(error);
}

/*
 * Start a client into the first state. A separate function because
 * it can be needed if the negotiation times out.
 */
static void
pppoe_start(sessp sp)
{
        hook_p  hook = sp->hook;
        node_p  node = NG_HOOK_NODE(hook);
        priv_p  privp = NG_NODE_PRIVATE(node);
        negp    neg = sp->neg;
        struct  mbuf *m0;
        int     error;

        /*
         * Kick the state machine into starting up.
         */
        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);
        sp->state = PPPOE_SINIT;
        /*
         * Reset the packet header to broadcast. Since we are
         * in a client mode use configured ethertype.
         */
        memcpy((void *)&neg->pkt->pkt_header.eh, &privp->eh,
            sizeof(struct ether_header));
        neg->pkt->pkt_header.ph.code = PADI_CODE;
        init_tags(sp);
        insert_tag(sp, &neg->host_uniq.hdr);
        insert_tag(sp, &neg->service.hdr);
        if (privp->max_payload.data != 0)
                insert_tag(sp, &privp->max_payload.hdr);
        make_packet(sp);
        /*
         * Send packet and prepare to retransmit it after timeout.
         */
        ng_callout(&neg->handle, node, hook, PPPOE_INITIAL_TIMEOUT * hz,
            pppoe_ticker, NULL, 0);
        neg->timeout = PPPOE_INITIAL_TIMEOUT * 2;
        m0 = m_copypacket(neg->m, M_NOWAIT);
        NG_SEND_DATA_ONLY(error, privp->ethernet_hook, m0);
}

static int
send_acname(sessp sp, const struct pppoe_tag *tag)
{
        int error, tlen;
        struct ng_mesg *msg;
        struct ngpppoe_sts *sts;

        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_ACNAME,
            sizeof(struct ngpppoe_sts), M_NOWAIT);
        if (msg == NULL)
                return (ENOMEM);

        sts = (struct ngpppoe_sts *)msg->data;
        tlen = min(NG_HOOKSIZ - 1, ntohs(tag->tag_len));
        strncpy(sts->hook, (const char *)(tag + 1), tlen);
        sts->hook[tlen] = '\0';
        NG_SEND_MSG_ID(error, NG_HOOK_NODE(sp->hook), msg, sp->creator, 0);

        return (error);
}

static int
send_sessionid(sessp sp)
{
        int error;
        struct ng_mesg *msg;

        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_SESSIONID,
            sizeof(uint16_t), M_NOWAIT);
        if (msg == NULL)
                return (ENOMEM);

        *(uint16_t *)msg->data = sp->Session_ID;
        NG_SEND_MSG_ID(error, NG_HOOK_NODE(sp->hook), msg, sp->creator, 0);

        return (error);
}

static int
send_maxp(sessp sp, const struct pppoe_tag *tag)
{
        int error;
        struct ng_mesg *msg;
        struct ngpppoe_maxp *maxp;

        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_SETMAXP,
            sizeof(struct ngpppoe_maxp), M_NOWAIT);
        if (msg == NULL)
                return (ENOMEM);

        maxp = (struct ngpppoe_maxp *)msg->data;
        strncpy(maxp->hook, NG_HOOK_NAME(sp->hook), NG_HOOKSIZ);
        maxp->data = ntohs(((const struct maxptag *)tag)->data);
        NG_SEND_MSG_ID(error, NG_HOOK_NODE(sp->hook), msg, sp->creator, 0);

        return (error);
}

static int
send_hurl(sessp sp, const struct pppoe_tag *tag)
{
        int error, tlen;
        struct ng_mesg *msg;
        struct ngpppoe_padm *padm;

        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_HURL,
            sizeof(struct ngpppoe_padm), M_NOWAIT);
        if (msg == NULL)
                return (ENOMEM);

        padm = (struct ngpppoe_padm *)msg->data;
        tlen = min(PPPOE_PADM_VALUE_SIZE - 1, ntohs(tag->tag_len));
        strncpy(padm->msg, (const char *)(tag + 1), tlen);
        padm->msg[tlen] = '\0';
        NG_SEND_MSG_ID(error, NG_HOOK_NODE(sp->hook), msg, sp->creator, 0);

        return (error);
}

static int
send_motm(sessp sp, const struct pppoe_tag *tag)
{
        int error, tlen;
        struct ng_mesg *msg;
        struct ngpppoe_padm *padm;

        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, NGM_PPPOE_MOTM,
            sizeof(struct ngpppoe_padm), M_NOWAIT);
        if (msg == NULL)
                return (ENOMEM);

        padm = (struct ngpppoe_padm *)msg->data;
        tlen = min(PPPOE_PADM_VALUE_SIZE - 1, ntohs(tag->tag_len));
        strncpy(padm->msg, (const char *)(tag + 1), tlen);
        padm->msg[tlen] = '\0';
        NG_SEND_MSG_ID(error, NG_HOOK_NODE(sp->hook), msg, sp->creator, 0);

        return (error);
}

/*
 * Receive data from session hook and do something with it.
 */
static int
ng_pppoe_rcvdata(hook_p hook, item_p item)
{
        node_p                  node = NG_HOOK_NODE(hook);
        const priv_p            privp = NG_NODE_PRIVATE(node);
        sessp                   sp = NG_HOOK_PRIVATE(hook);
        struct pppoe_full_hdr   *wh;
        struct mbuf             *m;
        int                     error;

        CTR6(KTR_NET, "%20s: node [%x] (%p) received %p on \"%s\" (%p)",
            __func__, node->nd_ID, node, item, hook->hk_name, hook);

        NGI_GET_M(item, m);
        switch (sp->state) {
        case    PPPOE_NEWCONNECTED:
        case    PPPOE_CONNECTED: {
                /*
                 * Remove PPP address and control fields, if any.
                 * For example, ng_ppp(4) always sends LCP packets
                 * with address and control fields as required by
                 * generic PPP. PPPoE is an exception to the rule.
                 */
                if (m->m_pkthdr.len >= 2) {
                        if (m->m_len < 2 && !(m = m_pullup(m, 2)))
                                LEAVE(ENOBUFS);
                        if (mtod(m, u_char *)[0] == 0xff &&
                            mtod(m, u_char *)[1] == 0x03)
                                m_adj(m, 2);
                }

                if (V_ng_pppoe_lcp_pcp && m->m_pkthdr.len >= 2 &&
                    m->m_len >= 2 && (m = m_pullup(m, 2)) &&
                    mtod(m, uint16_t *)[0] == htons(PROT_LCP))
                        EVL_APPLY_PRI(m, (uint8_t)(V_ng_pppoe_lcp_pcp & 0x7));

                /*
                 * Bang in a pre-made header, and set the length up
                 * to be correct. Then send it to the ethernet driver.
                 */
                M_PREPEND(m, sizeof(*wh), M_NOWAIT);
                if (m == NULL)
                        LEAVE(ENOBUFS);

                wh = mtod(m, struct pppoe_full_hdr *);
                bcopy(&sp->pkt_hdr, wh, sizeof(*wh));
                wh->ph.length = htons(m->m_pkthdr.len - sizeof(*wh));
                NG_FWD_NEW_DATA(error, item, privp->ethernet_hook, m);
                privp->packets_out++;
                break;
                }
        case    PPPOE_PRIMED: {
                struct {
                        struct pppoe_tag hdr;
                        union   uniq    data;
                } __packed      uniqtag;
                const struct pppoe_tag  *tag;
                struct mbuf     *m0;
                const struct pppoe_hdr  *ph;
                negp            neg = sp->neg;
                uint8_t         code;

                /*
                 * A PADI packet is being returned by the application
                 * that has set up this hook. This indicates that it
                 * wants us to offer service.
                 */
                if (m->m_len < sizeof(*wh)) {
                        m = m_pullup(m, sizeof(*wh));
                        if (m == NULL)
                                LEAVE(ENOBUFS);
                }
                wh = mtod(m, struct pppoe_full_hdr *);
                ph = &wh->ph;
                code = wh->ph.code;
                /* Use peers mode in session. */
                neg->pkt->pkt_header.eh.ether_type = wh->eh.ether_type;
                if (code != PADI_CODE)
                        LEAVE(EINVAL);
                ng_uncallout(&neg->handle, node);

                /*
                 * This is the first time we hear
                 * from the client, so note it's
                 * unicast address, replacing the
                 * broadcast address.
                 */
                bcopy(wh->eh.ether_shost,
                        neg->pkt->pkt_header.eh.ether_dhost,
                        ETHER_ADDR_LEN);
                sp->state = PPPOE_SOFFER;
                neg->timeout = 0;
                neg->pkt->pkt_header.ph.code = PADO_CODE;

                /*
                 * Start working out the tags to respond with.
                 */
                uniqtag.hdr.tag_type = PTT_AC_COOKIE;
                uniqtag.hdr.tag_len = htons((u_int16_t)sizeof(sp));
                uniqtag.data.pointer = sp;
                init_tags(sp);
                insert_tag(sp, &neg->ac_name.hdr); /* AC_NAME */
                if ((tag = get_tag(ph, PTT_SRV_NAME)))
                        insert_tag(sp, tag);      /* return service */
                /*
                 * If we have a NULL service request
                 * and have an extra service defined in this hook,
                 * then also add a tag for the extra service.
                 * XXX this is a hack. eventually we should be able
                 * to support advertising many services, not just one
                 */
                if (((tag == NULL) || (tag->tag_len == 0)) &&
                    (neg->service.hdr.tag_len != 0)) {
                        insert_tag(sp, &neg->service.hdr); /* SERVICE */
                }
                if ((tag = get_tag(ph, PTT_HOST_UNIQ)))
                        insert_tag(sp, tag); /* returned hostunique */
                insert_tag(sp, &uniqtag.hdr);
                scan_tags(sp, ph);
                make_packet(sp);
                /*
                 * Send the offer but if they don't respond
                 * in PPPOE_OFFER_TIMEOUT seconds, forget about it.
                 */
                ng_callout(&neg->handle, node, hook, PPPOE_OFFER_TIMEOUT * hz,
                    pppoe_ticker, NULL, 0);
                m0 = m_copypacket(sp->neg->m, M_NOWAIT);
                NG_FWD_NEW_DATA(error, item, privp->ethernet_hook, m0);
                privp->packets_out++;
                break;
                }

        /*
         * Packets coming from the hook make no sense
         * to sessions in the rest of states. Throw them away.
         */
        default:
                LEAVE(ENETUNREACH);
        }
quit:
        if (item)
                NG_FREE_ITEM(item);
        NG_FREE_M(m);
        return (error);
}

/*
 * Receive data from ether and do something with it.
 */
static int
ng_pppoe_rcvdata_ether(hook_p hook, item_p item)
{
        node_p                  node = NG_HOOK_NODE(hook);
        const priv_p            privp = NG_NODE_PRIVATE(node);
        sessp                   sp;
        const struct pppoe_tag  *utag = NULL, *tag = NULL;
        const struct pppoe_tag  sntag = { PTT_SRV_NAME, 0 };
        const struct pppoe_full_hdr *wh;
        const struct pppoe_hdr  *ph;
        negp                    neg = NULL;
        struct mbuf             *m;
        hook_p                  sendhook;
        int                     error = 0;
        uint16_t                length;
        uint8_t                 code;
        struct  mbuf            *m0;

        CTR6(KTR_NET, "%20s: node [%x] (%p) received %p on \"%s\" (%p)",
            __func__, node->nd_ID, node, item, hook->hk_name, hook);

        NGI_GET_M(item, m);
        /*
         * Dig out various fields from the packet.
         * Use them to decide where to send it.
         */
        privp->packets_in++;
        if( m->m_len < sizeof(*wh)) {
                m = m_pullup(m, sizeof(*wh)); /* Checks length */
                if (m == NULL) {
                        log(LOG_NOTICE, "ng_pppoe[%x]: couldn't "
                            "m_pullup(wh)\n", node->nd_ID);
                        LEAVE(ENOBUFS);
                }
        }
        wh = mtod(m, struct pppoe_full_hdr *);
        length = ntohs(wh->ph.length);
        switch(wh->eh.ether_type) {
        case    ETHERTYPE_PPPOE_3COM_DISC: /* fall through */
        case    ETHERTYPE_PPPOE_DISC:
                /*
                 * We need to try to make sure that the tag area
                 * is contiguous, or we could wander off the end
                 * of a buffer and make a mess.
                 * (Linux wouldn't have this problem).
                 */
                if (m->m_pkthdr.len <= MHLEN) {
                        if( m->m_len < m->m_pkthdr.len) {
                                m = m_pullup(m, m->m_pkthdr.len);
                                if (m == NULL) {
                                        log(LOG_NOTICE, "ng_pppoe[%x]: "
                                            "couldn't m_pullup(pkthdr)\n",
                                            node->nd_ID);
                                        LEAVE(ENOBUFS);
                                }
                        }
                }
                if (m->m_len != m->m_pkthdr.len) {
                        /*
                         * It's not all in one piece.
                         * We need to do extra work.
                         * Put it into a cluster.
                         */
                        struct mbuf *n;
                        n = m_dup(m, M_NOWAIT);
                        m_freem(m);
                        m = n;
                        if (m) {
                                /* just check we got a cluster */
                                if (m->m_len != m->m_pkthdr.len) {
                                        m_freem(m);
                                        m = NULL;
                                }
                        }
                        if (m == NULL) {
                                log(LOG_NOTICE, "ng_pppoe[%x]: packet "
                                    "fragmented\n", node->nd_ID);
                                LEAVE(EMSGSIZE);
                        }
                }
                wh = mtod(m, struct pppoe_full_hdr *);
                length = ntohs(wh->ph.length);
                ph = &wh->ph;
                code = wh->ph.code;

                switch(code) {
                case    PADI_CODE:
                        /*
                         * We are a server:
                         * Look for a hook with the required service and send
                         * the ENTIRE packet up there. It should come back to
                         * a new hook in PRIMED state. Look there for further
                         * processing.
                         */
                        tag = get_tag(ph, PTT_SRV_NAME);
                        if (tag == NULL)
                                tag = &sntag;

                        /*
                         * First, try to match Service-Name against our 
                         * listening hooks. If no success and we are in D-Link
                         * compat mode and Service-Name is empty, then we 
                         * broadcast the PADI to all listening hooks.
                         */
                        sendhook = pppoe_match_svc(node, tag);
                        if (sendhook != NULL)
                                NG_FWD_NEW_DATA(error, item, sendhook, m);
                        else if (privp->flags & COMPAT_DLINK &&
                                 ntohs(tag->tag_len) == 0)
                                error = pppoe_broadcast_padi(node, m);
                        else
                                error = ENETUNREACH;
                        break;
                case    PADO_CODE:
                        /*
                         * We are a client:
                         * Use the host_uniq tag to find the hook this is in
                         * response to. Received #2, now send #3
                         * For now simply accept the first we receive.
                         */
                        utag = get_tag(ph, PTT_HOST_UNIQ);
                        if (utag == NULL) {
                                log(LOG_NOTICE, "ng_pppoe[%x]: no host "
                                    "unique field\n", node->nd_ID);
                                LEAVE(ENETUNREACH);
                        }

                        sendhook = pppoe_finduniq(node, utag);
                        if (sendhook == NULL) {
                                log(LOG_NOTICE, "ng_pppoe[%x]: no "
                                    "matching session\n", node->nd_ID);
                                LEAVE(ENETUNREACH);
                        }

                        /*
                         * Check the session is in the right state.
                         * It needs to be in PPPOE_SINIT.
                         */
                        sp = NG_HOOK_PRIVATE(sendhook);
                        if (sp->state == PPPOE_SREQ ||
                            sp->state == PPPOE_CONNECTED) {
                                break;  /* Multiple PADO is OK. */
                        }
                        if (sp->state != PPPOE_SINIT) {
                                log(LOG_NOTICE, "ng_pppoe[%x]: session "
                                    "in wrong state\n", node->nd_ID);
                                LEAVE(ENETUNREACH);
                        }
                        neg = sp->neg;
                        /* If requested specific AC-name, check it. */
                        if (neg->ac_name_len) {
                                tag = get_tag(ph, PTT_AC_NAME);
                                if (!tag) {
                                        /* No PTT_AC_NAME in PADO */
                                        break;
                                }
                                if (neg->ac_name_len != htons(tag->tag_len) ||
                                    strncmp(neg->ac_name.data,
                                    (const char *)(tag + 1),
                                    neg->ac_name_len) != 0) {
                                        break;
                                }
                        }
                        sp->state = PPPOE_SREQ;
                        ng_uncallout(&neg->handle, node);

                        /*
                         * This is the first time we hear
                         * from the server, so note it's
                         * unicast address, replacing the
                         * broadcast address .
                         */
                        bcopy(wh->eh.ether_shost,
                                neg->pkt->pkt_header.eh.ether_dhost,
                                ETHER_ADDR_LEN);
                        neg->timeout = 0;
                        neg->pkt->pkt_header.ph.code = PADR_CODE;
                        init_tags(sp);
                        insert_tag(sp, utag);           /* Host Unique */
                        if ((tag = get_tag(ph, PTT_AC_COOKIE)))
                                insert_tag(sp, tag);    /* return cookie */
                        if ((tag = get_tag(ph, PTT_AC_NAME))) { 
                                insert_tag(sp, tag);    /* return it */
                                send_acname(sp, tag);
                        }
                        if ((tag = get_tag(ph, PTT_MAX_PAYL)) &&
                            (privp->max_payload.data != 0))
                                insert_tag(sp, tag);    /* return it */
                        insert_tag(sp, &neg->service.hdr); /* Service */
                        scan_tags(sp, ph);
                        make_packet(sp);
                        sp->state = PPPOE_SREQ;
                        ng_callout(&neg->handle, node, sp->hook,
                            PPPOE_INITIAL_TIMEOUT * hz,
                            pppoe_ticker, NULL, 0);
                        neg->timeout = PPPOE_INITIAL_TIMEOUT * 2;
                        m0 = m_copypacket(neg->m, M_NOWAIT);
                        NG_FWD_NEW_DATA(error, item, privp->ethernet_hook, m0);
                        break;
                case    PADR_CODE:
                        /*
                         * We are a server:
                         * Use the ac_cookie tag to find the
                         * hook this is in response to.
                         */
                        utag = get_tag(ph, PTT_AC_COOKIE);
                        if ((utag == NULL) ||
                            (ntohs(utag->tag_len) != sizeof(sp))) {
                                LEAVE(ENETUNREACH);
                        }

                        sendhook = pppoe_findcookie(node, utag);
                        if (sendhook == NULL)
                                LEAVE(ENETUNREACH);

                        /*
                         * Check the session is in the right state.
                         * It needs to be in PPPOE_SOFFER or PPPOE_NEWCONNECTED.
                         * If the latter, then this is a retry by the client,
                         * so be nice, and resend.
                         */
                        sp = NG_HOOK_PRIVATE(sendhook);
                        if (sp->state == PPPOE_NEWCONNECTED) {
                                /*
                                 * Whoa! drop back to resend that PADS packet.
                                 * We should still have a copy of it.
                                 */
                                sp->state = PPPOE_SOFFER;
                        } else if (sp->state != PPPOE_SOFFER)
                                LEAVE (ENETUNREACH);
                        neg = sp->neg;
                        ng_uncallout(&neg->handle, node);
                        neg->pkt->pkt_header.ph.code = PADS_CODE;
                        if (sp->Session_ID == 0) {
                                neg->pkt->pkt_header.ph.sid =
                                    htons(pppoe_getnewsession(sp));
                        }
                        send_sessionid(sp);
                        neg->timeout = 0;
                        /*
                         * start working out the tags to respond with.
                         */
                        init_tags(sp);
                        insert_tag(sp, &neg->ac_name.hdr); /* AC_NAME */
                        if ((tag = get_tag(ph, PTT_SRV_NAME)))
                                insert_tag(sp, tag);/* return service */
                        if ((tag = get_tag(ph, PTT_HOST_UNIQ)))
                                insert_tag(sp, tag); /* return it */
                        insert_tag(sp, utag);   /* ac_cookie */
                        scan_tags(sp, ph);
                        make_packet(sp);
                        sp->state = PPPOE_NEWCONNECTED;

                        /* Send the PADS without a timeout - we're now connected. */
                        m0 = m_copypacket(sp->neg->m, M_NOWAIT);
                        NG_FWD_NEW_DATA(error, item, privp->ethernet_hook, m0);

                        /*
                         * Having sent the last Negotiation header,
                         * Set up the stored packet header to be correct for
                         * the actual session. But keep the negotialtion stuff
                         * around in case we need to resend this last packet.
                         * We'll discard it when we move from NEWCONNECTED
                         * to CONNECTED
                         */
                        sp->pkt_hdr = neg->pkt->pkt_header;
                        /* Configure ethertype depending on what
                         * ethertype was used at discovery phase */
                        if (sp->pkt_hdr.eh.ether_type ==
                            ETHERTYPE_PPPOE_3COM_DISC)
                                sp->pkt_hdr.eh.ether_type
                                        = ETHERTYPE_PPPOE_3COM_SESS;
                        else
                                sp->pkt_hdr.eh.ether_type
                                        = ETHERTYPE_PPPOE_SESS;
                        sp->pkt_hdr.ph.code = 0;
                        pppoe_send_event(sp, NGM_PPPOE_SUCCESS);
                        break;
                case    PADS_CODE:
                        /*
                         * We are a client:
                         * Use the host_uniq tag to find the hook this is in
                         * response to. Take the session ID and store it away.
                         * Also make sure the pre-made header is correct and
                         * set us into Session mode.
                         */
                        utag = get_tag(ph, PTT_HOST_UNIQ);
                        if (utag == NULL) {
                                LEAVE (ENETUNREACH);
                        }
                        sendhook = pppoe_finduniq(node, utag);
                        if (sendhook == NULL)
                                LEAVE(ENETUNREACH);

                        /*
                         * Check the session is in the right state.
                         * It needs to be in PPPOE_SREQ.
                         */
                        sp = NG_HOOK_PRIVATE(sendhook);
                        if (sp->state != PPPOE_SREQ)
                                LEAVE(ENETUNREACH);
                        neg = sp->neg;
                        ng_uncallout(&neg->handle, node);
                        neg->pkt->pkt_header.ph.sid = wh->ph.sid;
                        sp->Session_ID = ntohs(wh->ph.sid);
                        pppoe_addsession(sp);
                        send_sessionid(sp);
                        neg->timeout = 0;
                        sp->state = PPPOE_CONNECTED;
                        /*
                         * Now we have gone to Connected mode,
                         * Free all resources needed for negotiation.
                         * Keep a copy of the header we will be using.
                         */
                        sp->pkt_hdr = neg->pkt->pkt_header;
                        if (privp->flags & COMPAT_3COM)
                                sp->pkt_hdr.eh.ether_type
                                        = ETHERTYPE_PPPOE_3COM_SESS;
                        else
                                sp->pkt_hdr.eh.ether_type
                                        = ETHERTYPE_PPPOE_SESS;
                        sp->pkt_hdr.ph.code = 0;
                        m_freem(neg->m);
                        free(sp->neg, M_NETGRAPH_PPPOE);
                        sp->neg = NULL;
                        if ((tag = get_tag(ph, PTT_MAX_PAYL)) &&
                            (privp->max_payload.data != 0))
                                send_maxp(sp, tag);
                        pppoe_send_event(sp, NGM_PPPOE_SUCCESS);
                        break;
                case    PADT_CODE:
                        /*
                         * Find matching peer/session combination.
                         */
                        sp = pppoe_findsession(privp, wh);
                        if (sp == NULL)
                                LEAVE(ENETUNREACH);
                        /* Disconnect that hook. */
                        ng_rmhook_self(sp->hook);
                        break;
                case    PADM_CODE:
                        /*
                         * We are a client:
                         * find matching peer/session combination.
                         */
                        sp = pppoe_findsession(privp, wh);
                        if (sp == NULL)
                                LEAVE (ENETUNREACH);
                        if ((tag = get_tag(ph, PTT_HURL)))
                                send_hurl(sp, tag);
                        if ((tag = get_tag(ph, PTT_MOTM)))
                                send_motm(sp, tag);
                        break;
                default:
                        LEAVE(EPFNOSUPPORT);
                }
                break;
        case    ETHERTYPE_PPPOE_3COM_SESS:
        case    ETHERTYPE_PPPOE_SESS:
                /*
                 * Find matching peer/session combination.
                 */
                sp = pppoe_findsession(privp, wh);
                if (sp == NULL)
                        LEAVE (ENETUNREACH);
                m_adj(m, sizeof(*wh));

                /* If packet too short, dump it. */
                if (m->m_pkthdr.len < length)
                        LEAVE(EMSGSIZE);
                /* Also need to trim excess at the end */
                if (m->m_pkthdr.len > length) {
                        m_adj(m, -((int)(m->m_pkthdr.len - length)));
                }
                if ( sp->state != PPPOE_CONNECTED) {
                        if (sp->state == PPPOE_NEWCONNECTED) {
                                sp->state = PPPOE_CONNECTED;
                                /*
                                 * Now we have gone to Connected mode,
                                 * Free all resources needed for negotiation.
                                 * Be paranoid about whether there may be
                                 * a timeout.
                                 */
                                m_freem(sp->neg->m);
                                ng_uncallout(&sp->neg->handle, node);
                                free(sp->neg, M_NETGRAPH_PPPOE);
                                sp->neg = NULL;
                        } else {
                                LEAVE (ENETUNREACH);
                        }
                }
                NG_FWD_NEW_DATA(error, item, sp->hook, m);
                break;
        default:
                LEAVE(EPFNOSUPPORT);
        }
quit:
        if (item)
                NG_FREE_ITEM(item);
        NG_FREE_M(m);
        return (error);
}

/*
 * Receive data from debug hook and bypass it to ether.
 */
static int
ng_pppoe_rcvdata_debug(hook_p hook, item_p item)
{
        node_p          node = NG_HOOK_NODE(hook);
        const priv_p    privp = NG_NODE_PRIVATE(node);
        int             error;

        CTR6(KTR_NET, "%20s: node [%x] (%p) received %p on \"%s\" (%p)",
            __func__, node->nd_ID, node, item, hook->hk_name, hook);

        NG_FWD_ITEM_HOOK(error, item, privp->ethernet_hook);
        privp->packets_out++;
        return (error);
}

/*
 * Do local shutdown processing..
 * If we are a persistent device, we might refuse to go away, and
 * we'd only remove our links and reset ourself.
 */
static int
ng_pppoe_shutdown(node_p node)
{
        const priv_p privp = NG_NODE_PRIVATE(node);
        int     i;

        for (i = 0; i < SESSHASHSIZE; i++)
            mtx_destroy(&privp->sesshash[i].mtx);
        NG_NODE_SET_PRIVATE(node, NULL);
        NG_NODE_UNREF(privp->node);
        free(privp, M_NETGRAPH_PPPOE);
        return (0);
}

/*
 * Hook disconnection
 *
 * Clean up all dangling links and information about the session/hook.
 * For this type, removal of the last link destroys the node.
 */
static int
ng_pppoe_disconnect(hook_p hook)
{
        node_p node = NG_HOOK_NODE(hook);
        priv_p privp = NG_NODE_PRIVATE(node);
        sessp   sp;

        if (hook == privp->debug_hook) {
                privp->debug_hook = NULL;
        } else if (hook == privp->ethernet_hook) {
                privp->ethernet_hook = NULL;
                if (NG_NODE_IS_VALID(node))
                        ng_rmnode_self(node);
        } else {
                sp = NG_HOOK_PRIVATE(hook);
                if (sp->state != PPPOE_SNONE ) {
                        pppoe_send_event(sp, NGM_PPPOE_CLOSE);
                }
                /*
                 * According to the spec, if we are connected,
                 * we should send a DISC packet if we are shutting down
                 * a session.
                 */
                if ((privp->ethernet_hook)
                && ((sp->state == PPPOE_CONNECTED)
                 || (sp->state == PPPOE_NEWCONNECTED))) {
                        struct mbuf *m;

                        /* Generate a packet of that type. */
                        m = m_gethdr(M_NOWAIT, MT_DATA);
                        if (m == NULL)
                                log(LOG_NOTICE, "ng_pppoe[%x]: session out of "
                                    "mbufs\n", node->nd_ID);
                        else {
                                struct epoch_tracker et;
                                struct pppoe_full_hdr *wh;
                                struct pppoe_tag *tag;
                                int     msglen = strlen(SIGNOFF);
                                int     error = 0;

                                wh = mtod(m, struct pppoe_full_hdr *);
                                bcopy(&sp->pkt_hdr, wh, sizeof(*wh));

                                /* Revert the stored header to DISC/PADT mode. */
                                wh->ph.code = PADT_CODE;
                                /*
                                 * Configure ethertype depending on what
                                 * was used during sessions stage.
                                 */
                                if (wh->eh.ether_type == 
                                    ETHERTYPE_PPPOE_3COM_SESS)
                                        wh->eh.ether_type = ETHERTYPE_PPPOE_3COM_DISC;
                                else
                                        wh->eh.ether_type = ETHERTYPE_PPPOE_DISC;
                                /*
                                 * Add a General error message and adjust
                                 * sizes.
                                 */
                                tag = (void *)(&wh->ph + 1);
                                tag->tag_type = PTT_GEN_ERR;
                                tag->tag_len = htons((u_int16_t)msglen);
                                strncpy((char *)(tag + 1), SIGNOFF, msglen);
                                m->m_pkthdr.len = m->m_len = sizeof(*wh) + sizeof(*tag) +
                                    msglen;
                                wh->ph.length = htons(sizeof(*tag) + msglen);

                                NET_EPOCH_ENTER(et);
                                NG_SEND_DATA_ONLY(error,
                                        privp->ethernet_hook, m);
                                NET_EPOCH_EXIT(et);
                        }
                }
                if (sp->state == PPPOE_LISTENING)
                        LIST_REMOVE(sp, sessions);
                else if (sp->Session_ID)
                        pppoe_delsession(sp);
                /*
                 * As long as we have somewhere to store the timeout handle,
                 * we may have a timeout pending.. get rid of it.
                 */
                if (sp->neg) {
                        ng_uncallout(&sp->neg->handle, node);
                        if (sp->neg->m)
                                m_freem(sp->neg->m);
                        free(sp->neg, M_NETGRAPH_PPPOE);
                }
                free(sp, M_NETGRAPH_PPPOE);
                NG_HOOK_SET_PRIVATE(hook, NULL);
        }
        if ((NG_NODE_NUMHOOKS(node) == 0) &&
            (NG_NODE_IS_VALID(node)))
                ng_rmnode_self(node);
        return (0);
}

/*
 * Timeouts come here.
 */
static void
pppoe_ticker(node_p node, hook_p hook, void *arg1, int arg2)
{
        priv_p privp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
        sessp   sp = NG_HOOK_PRIVATE(hook);
        negp    neg = sp->neg;
        struct mbuf *m0 = NULL;
        int     error = 0;

        CTR6(KTR_NET, "%20s: node [%x] (%p) hook \"%s\" (%p) session %d",
            __func__, node->nd_ID, node, hook->hk_name, hook, sp->Session_ID);
        switch(sp->state) {
                /*
                 * Resend the last packet, using an exponential backoff.
                 * After a period of time, stop growing the backoff,
                 * And either leave it, or revert to the start.
                 */
        case    PPPOE_SINIT:
        case    PPPOE_SREQ:
                /* Timeouts on these produce resends. */
                m0 = m_copypacket(sp->neg->m, M_NOWAIT);
                NG_SEND_DATA_ONLY( error, privp->ethernet_hook, m0);
                ng_callout(&neg->handle, node, hook, neg->timeout * hz,
                    pppoe_ticker, NULL, 0);
                if ((neg->timeout <<= 1) > PPPOE_TIMEOUT_LIMIT) {
                        if (sp->state == PPPOE_SREQ) {
                                /* Revert to SINIT mode. */
                                pppoe_start(sp);
                        } else {
                                neg->timeout = PPPOE_TIMEOUT_LIMIT;
                        }
                }
                break;
        case    PPPOE_PRIMED:
        case    PPPOE_SOFFER:
                /* A timeout on these says "give up" */
                ng_rmhook_self(hook);
                break;
        default:
                /* Timeouts have no meaning in other states. */
                log(LOG_NOTICE, "ng_pppoe[%x]: unexpected timeout\n",
                    node->nd_ID);
        }
}

/*
 * Parse an incoming packet to see if any tags should be copied to the
 * output packet. Don't do any tags that have been handled in the main
 * state machine.
 */
static const struct pppoe_tag*
scan_tags(sessp sp, const struct pppoe_hdr* ph)
{
        const char *const end = (const char *)next_tag(ph);
        const char *ptn;
        const struct pppoe_tag *pt = (const void *)(ph + 1);

        /*
         * Keep processing tags while a tag header will still fit.
         */
        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        while((const char*)(pt + 1) <= end) {
                /*
                 * If the tag data would go past the end of the packet, abort.
                 */
                ptn = (((const char *)(pt + 1)) + ntohs(pt->tag_len));
                if(ptn > end)
                        return NULL;

                switch (pt->tag_type) {
                case    PTT_RELAY_SID:
                        insert_tag(sp, pt);
                        break;
                case    PTT_EOL:
                        return NULL;
                case    PTT_SRV_NAME:
                case    PTT_AC_NAME:
                case    PTT_HOST_UNIQ:
                case    PTT_AC_COOKIE:
                case    PTT_VENDOR:
                case    PTT_SRV_ERR:
                case    PTT_SYS_ERR:
                case    PTT_GEN_ERR:
                case    PTT_MAX_PAYL:
                case    PTT_HURL:
                case    PTT_MOTM:
                        break;
                }
                pt = (const struct pppoe_tag*)ptn;
        }
        return NULL;
}

static  int
pppoe_send_event(sessp sp, enum cmd cmdid)
{
        int error;
        struct ng_mesg *msg;
        struct ngpppoe_sts *sts;

        CTR2(KTR_NET, "%20s: called %d", __func__, sp->Session_ID);

        NG_MKMESSAGE(msg, NGM_PPPOE_COOKIE, cmdid,
                        sizeof(struct ngpppoe_sts), M_NOWAIT);
        if (msg == NULL)
                return (ENOMEM);
        sts = (struct ngpppoe_sts *)msg->data;
        strncpy(sts->hook, NG_HOOK_NAME(sp->hook), NG_HOOKSIZ);
        NG_SEND_MSG_ID(error, NG_HOOK_NODE(sp->hook), msg, sp->creator, 0);
        return (error);
}