/*      $KAME: rrenumd.c,v 1.20 2000/11/08 02:40:53 itojun Exp $        */

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * 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.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``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 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.
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/time.h>

#include <string.h>

#include <net/route.h>

#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/icmp6.h>

#include <arpa/inet.h>

#ifdef IPSEC
#include <netipsec/ipsec.h>
#endif

#include <stdio.h>
#include <err.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <syslog.h>

#include "rrenumd.h"

#define LL_ALLROUTERS "ff02::2"
#define SL_ALLROUTERS "ff05::2"

#define RR_MCHLIM_DEFAULT 64

#ifndef IN6_IS_SCOPE_LINKLOCAL
#define IN6_IS_SCOPE_LINKLOCAL(a)       \
        ((IN6_IS_ADDR_LINKLOCAL(a)) ||  \
         (IN6_IS_ADDR_MC_LINKLOCAL(a)))
#endif /* IN6_IS_SCOPE_LINKLOCAL */

struct flags {
        u_long debug : 1;
        u_long fg : 1;
#ifdef IPSEC
#ifdef IPSEC_POLICY_IPSEC
        u_long policy : 1;
#else /* IPSEC_POLICY_IPSEC */
        u_long auth : 1;
        u_long encrypt : 1;
#endif /* IPSEC_POLICY_IPSEC */
#endif /*IPSEC*/
};

struct msghdr sndmhdr;
struct msghdr rcvmhdr;
struct sockaddr_in6 from;
struct sockaddr_in6 sin6_ll_allrouters;

int s4, s6;
int with_v4dest, with_v6dest;
struct in6_addr prefix; /* ADHOC */
int prefixlen = 64; /* ADHOC */

extern int parse(FILE **);

static void show_usage(void);
static void init_sin6(struct sockaddr_in6 *, const char *);
#if 0
static void join_multi(const char *);
#endif
static void init_globals(void);
static void config(FILE **);
#ifdef IPSEC_POLICY_IPSEC
static void sock6_open(struct flags *, char *);
static void sock4_open(struct flags *, char *);
#else
static void sock6_open(struct flags *);
static void sock4_open(struct flags *);
#endif
static void rrenum_output(struct payload_list *, struct dst_list *);
static void rrenum_snd_eachdst(struct payload_list *);
#if 0
static void rrenum_snd_fullsequence(void);
#endif
static void rrenum_input(int);
int main(int, char *[]);


/* Print usage. Don't call this after daemonized. */
static void
show_usage()
{
        fprintf(stderr, "usage: rrenumd [-c conf_file|-s] [-df"
#ifdef IPSEC
#ifdef IPSEC_POLICY_IPSEC
                "] [-P policy"
#else /* IPSEC_POLICY_IPSEC */
                "AE"
#endif /* IPSEC_POLICY_IPSEC */
#endif /* IPSEC */
                "]\n");
        exit(1);
}

static void
init_sin6(struct sockaddr_in6 *sin6, const char *addr_ascii)
{
        memset(sin6, 0, sizeof(*sin6));
        sin6->sin6_len = sizeof(*sin6);
        sin6->sin6_family = AF_INET6;
        if (inet_pton(AF_INET6, addr_ascii, &sin6->sin6_addr) != 1)
                ; /* XXX do something */
}

#if 0  /* XXX: not necessary ?? */
static void
join_multi(const char *addrname)
{
        struct ipv6_mreq mreq;

        if (inet_pton(AF_INET6, addrname, &mreq.ipv6mr_multiaddr.s6_addr)
            != 1) {
                syslog(LOG_ERR, "<%s> inet_pton failed(library bug?)",
                       __func__);
                exit(1);
        }
        /* ADHOC: currently join only one */
        {
                if ((mreq.ipv6mr_interface = if_nametoindex(ifname)) == 0) {
                        syslog(LOG_ERR, "<%s> ifname %s should be invalid: %s",
                               __func__, ifname, strerror(errno));
                        exit(1);
                }
                if (setsockopt(s, IPPROTO_IPV6, IPV6_JOIN_GROUP,
                               &mreq,
                               sizeof(mreq)) < 0) {
                        syslog(LOG_ERR, "<%s> IPV6_JOIN_GROUP on %s: %s",
                               __func__, ifname, strerror(errno));
                        exit(1);
                }
        }
}
#endif

static void
init_globals()
{
        static struct iovec rcviov;
        static u_char rprdata[4500]; /* maximal MTU of connected links */
        static u_char *rcvcmsgbuf = NULL;
        static u_char *sndcmsgbuf = NULL;
        int sndcmsglen, rcvcmsglen;

        /* init ll_allrouters */
        init_sin6(&sin6_ll_allrouters, LL_ALLROUTERS);

        /* initialize msghdr for receiving packets */
        rcviov.iov_base = (caddr_t)rprdata;
        rcviov.iov_len = sizeof(rprdata);
        rcvmhdr.msg_namelen = sizeof(struct sockaddr_in6);
        rcvmhdr.msg_iov = &rcviov;
        rcvmhdr.msg_iovlen = 1;
        rcvcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
                CMSG_SPACE(sizeof(int));
        if (rcvcmsgbuf == NULL &&
            (rcvcmsgbuf = (u_char *)malloc(rcvcmsglen)) == NULL) {
                syslog(LOG_ERR, "<%s>: malloc failed", __func__);
                exit(1);
        }
        rcvmhdr.msg_control = (caddr_t)rcvcmsgbuf;
        rcvmhdr.msg_controllen = rcvcmsglen;

        /* initialize msghdr for sending packets */
        sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
        sndmhdr.msg_iovlen = 1;
        sndcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
                CMSG_SPACE(sizeof(int));
        if (sndcmsgbuf == NULL &&
            (sndcmsgbuf = (u_char *)malloc(sndcmsglen)) == NULL) {
                syslog(LOG_ERR, "<%s>: malloc failed", __func__);
                exit(1);
        }
        sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
        sndmhdr.msg_controllen = sndcmsglen;
}

static void
config(FILE **fpp)
{
        struct payload_list *pl;
        struct iovec *iov;
        struct icmp6_router_renum *irr;
        struct rr_pco_match *rpm;

        if (parse(fpp) < 0) {
                syslog(LOG_ERR, "<%s> parse failed", __func__);
                exit(1);
        }

        /* initialize fields not configured by parser */
        for (pl = pl_head; pl; pl = pl->pl_next) {
                iov = (struct iovec *)&pl->pl_sndiov;
                irr = (struct icmp6_router_renum *)&pl->pl_irr;
                rpm = (struct rr_pco_match *)&pl->pl_rpm;

                irr->rr_type = ICMP6_ROUTER_RENUMBERING;
                irr->rr_code = 0;
                /*
                 * now we don't support multiple PCOs in a rr message.
                 * so segment number is not supported.
                 */
                /* TODO: rr flags config in parser */
                irr->rr_flags |= ICMP6_RR_FLAGS_SPECSITE;
                /* TODO: max delay config in parser */

                /*
                 * means only 1 use_prefix is contained as router-renum-05.txt.
                 * now we don't support multiple PCOs in a rr message,
                 * nor multiple use_prefix in one PCO.
                 */
                rpm->rpm_len = 4*1 +3;
                rpm->rpm_ordinal = 0;
                iov->iov_base = (caddr_t)irr;
                iov->iov_len =  sizeof(struct icmp6_router_renum)
                        + sizeof(struct rr_pco_match)
                        + sizeof(struct rr_pco_use);
        }
}

static void
sock6_open(struct flags *flags
#ifdef IPSEC_POLICY_IPSEC
           , char *policy
#endif /* IPSEC_POLICY_IPSEC */
           )
{
        struct icmp6_filter filt;
        int on;
#ifdef IPSEC
#ifndef IPSEC_POLICY_IPSEC
        int optval;
#endif
#endif

        if (with_v6dest == 0)
                return;
        if (with_v6dest &&
            (s6 = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
                syslog(LOG_ERR, "<%s> socket(v6): %s", __func__,
                       strerror(errno));
                exit(1);
        }

        /*
         * join all routers multicast addresses.
         */
#if 0 /* XXX: not necessary ?? */
        join_multi(LL_ALLROUTERS);
        join_multi(SL_ALLROUTERS);
#endif

        /* set icmpv6 filter */
        ICMP6_FILTER_SETBLOCKALL(&filt);
        ICMP6_FILTER_SETPASS(ICMP6_ROUTER_RENUMBERING, &filt);
        if (setsockopt(s6, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
                       sizeof(filt)) < 0) {
                syslog(LOG_ERR, "<%s> IICMP6_FILTER: %s",
                       __func__, strerror(errno));
                exit(1);
        }

        /* specify to tell receiving interface */
        on = 1;
        if (setsockopt(s6, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
                       sizeof(on)) < 0) {
                syslog(LOG_ERR, "<%s> IPV6_RECVPKTINFO: %s",
                       __func__, strerror(errno));
                exit(1);
        }

#ifdef IPSEC
#ifdef IPSEC_POLICY_IPSEC
        if (flags->policy) {
                char *buf;
                buf = ipsec_set_policy(policy, strlen(policy));
                if (buf == NULL)
                        errx(1, "%s", ipsec_strerror());
                /* XXX should handle in/out bound policy. */
                if (setsockopt(s6, IPPROTO_IPV6, IPV6_IPSEC_POLICY,
                                buf, ipsec_get_policylen(buf)) < 0)
                        err(1, "setsockopt(IPV6_IPSEC_POLICY)");
                free(buf);
        }
#else /* IPSEC_POLICY_IPSEC */
        if (flags->auth) {
                optval = IPSEC_LEVEL_REQUIRE;
                if (setsockopt(s6, IPPROTO_IPV6, IPV6_AUTH_TRANS_LEVEL,
                               &optval, sizeof(optval)) == -1) {
                        syslog(LOG_ERR, "<%s> IPV6_AUTH_TRANS_LEVEL: %s",
                               __func__, strerror(errno));
                        exit(1);
                }
        }
        if (flags->encrypt) {
                optval = IPSEC_LEVEL_REQUIRE;
                if (setsockopt(s6, IPPROTO_IPV6, IPV6_ESP_TRANS_LEVEL,
                                &optval, sizeof(optval)) == -1) {
                        syslog(LOG_ERR, "<%s> IPV6_ESP_TRANS_LEVEL: %s",
                               __func__, strerror(errno));
                        exit(1);
                }
        }
#endif /* IPSEC_POLICY_IPSEC */
#endif /* IPSEC */
}

static void
sock4_open(struct flags *flags
#ifdef IPSEC_POLICY_IPSEC
           , char *policy
#endif /* IPSEC_POLICY_IPSEC */
           )
{
#ifdef IPSEC
#ifndef IPSEC_POLICY_IPSEC
        int optval;
#endif
#endif

        if (with_v4dest == 0)
                return;
        if ((s4 = socket(AF_INET, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
                syslog(LOG_ERR, "<%s> socket(v4): %s", __func__,
                       strerror(errno));
                exit(1);
        }

#if 0 /* XXX: not necessary ?? */
        /*
         * join all routers multicast addresses.
         */
        some_join_function();
#endif

#ifdef IPSEC
#ifdef IPSEC_POLICY_IPSEC
        if (flags->policy) {
                char *buf;
                buf = ipsec_set_policy(policy, strlen(policy));
                if (buf == NULL)
                        errx(1, "%s", ipsec_strerror());
                /* XXX should handle in/out bound policy. */
                if (setsockopt(s4, IPPROTO_IP, IP_IPSEC_POLICY,
                                buf, ipsec_get_policylen(buf)) < 0)
                        err(1, "setsockopt(IP_IPSEC_POLICY)");
                free(buf);
        }
#else /* IPSEC_POLICY_IPSEC */
        if (flags->auth) {
                optval = IPSEC_LEVEL_REQUIRE;
                if (setsockopt(s4, IPPROTO_IP, IP_AUTH_TRANS_LEVEL,
                               &optval, sizeof(optval)) == -1) {
                        syslog(LOG_ERR, "<%s> IP_AUTH_TRANS_LEVEL: %s",
                               __func__, strerror(errno));
                        exit(1);
                }
        }
        if (flags->encrypt) {
                optval = IPSEC_LEVEL_REQUIRE;
                if (setsockopt(s4, IPPROTO_IP, IP_ESP_TRANS_LEVEL,
                                &optval, sizeof(optval)) == -1) {
                        syslog(LOG_ERR, "<%s> IP_ESP_TRANS_LEVEL: %s",
                               __func__, strerror(errno));
                        exit(1);
                }
        }
#endif /* IPSEC_POLICY_IPSEC */
#endif /* IPSEC */
}

static void
rrenum_output(struct payload_list *pl, struct dst_list *dl)
{
        int i, msglen = 0;
        struct cmsghdr *cm;
        struct in6_pktinfo *pi;
        struct sockaddr_in6 *sin6 = NULL;

        sndmhdr.msg_name = (caddr_t)dl->dl_dst;
        if (dl->dl_dst->sa_family == AF_INET6)
                sin6 = (struct sockaddr_in6 *)dl->dl_dst;

        if (sin6 != NULL &&
            IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) {
                int hoplimit = RR_MCHLIM_DEFAULT;

                cm = CMSG_FIRSTHDR(&sndmhdr);
                /* specify the outgoing interface */
                cm->cmsg_level = IPPROTO_IPV6;
                cm->cmsg_type = IPV6_PKTINFO;
                cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
                pi = (struct in6_pktinfo *)CMSG_DATA(cm);
                memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));       /*XXX*/
                pi->ipi6_ifindex = sin6->sin6_scope_id;
                msglen += CMSG_LEN(sizeof(struct in6_pktinfo));

                /* specify the hop limit of the packet if dest is link local */
                /* not defined by router-renum-05.txt, but maybe its OK */
                cm = CMSG_NXTHDR(&sndmhdr, cm);
                cm->cmsg_level = IPPROTO_IPV6;
                cm->cmsg_type = IPV6_HOPLIMIT;
                cm->cmsg_len = CMSG_LEN(sizeof(int));
                memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
                msglen += CMSG_LEN(sizeof(int));
        }
        sndmhdr.msg_controllen = msglen;
        if (sndmhdr.msg_controllen == 0)
                sndmhdr.msg_control = 0;

        sndmhdr.msg_iov = &pl->pl_sndiov;
        i = sendmsg(dl->dl_dst->sa_family == AF_INET ? s4 : s6, &sndmhdr, 0);

        if (i < 0 || i != sndmhdr.msg_iov->iov_len)
                syslog(LOG_ERR, "<%s> sendmsg: %s", __func__,
                       strerror(errno));
}

static void
rrenum_snd_eachdst(struct payload_list *pl)
{
        struct dst_list *dl;

        for (dl = dl_head; dl; dl = dl->dl_next) {
                rrenum_output(pl, dl);
        }
}

#if 0
static void
rrenum_snd_fullsequence()
{
        struct payload_list *pl;

        for (pl = pl_head; pl; pl = pl->pl_next) {
                rrenum_snd_eachdst(pl);
        }
}
#endif

static void
rrenum_input(int s)
{
        int i;
        struct icmp6_router_renum *rr;

        /* get message */
        if ((i = recvmsg(s, &rcvmhdr, 0)) < 0) {
                syslog(LOG_ERR, "<%s> recvmsg: %s", __func__,
                       strerror(errno));
                return;
        }
        if (s == s4)
                i -= sizeof(struct ip);
        if (i < sizeof(struct icmp6_router_renum)) {
                syslog(LOG_ERR, "<%s> packet size(%d) is too short",
                       __func__, i);
                return;
        }
        if (s == s4) {
                struct ip *ip = (struct ip *)rcvmhdr.msg_iov->iov_base;

                rr = (struct icmp6_router_renum *)(ip + 1);
        } else /* s == s6 */
                rr = (struct icmp6_router_renum *)rcvmhdr.msg_iov->iov_base;

        switch(rr->rr_code) {
        case ICMP6_ROUTER_RENUMBERING_COMMAND:
                /* COMMAND will be processed by rtadvd */
                break;
        case ICMP6_ROUTER_RENUMBERING_RESULT:
                /* TODO: receiving result message */
                break;
        default:
                syslog(LOG_ERR, "<%s> received unknown code %d",
                       __func__, rr->rr_code);
                break;
        }
}

int
main(int argc, char *argv[])
{
        FILE *fp = stdin;
        fd_set fdset;
        struct timeval timeout;
        int ch, i, maxfd = 0, send_counter = 0;
        struct flags flags;
        struct payload_list *pl;
#ifdef IPSEC_POLICY_IPSEC
        char *policy = NULL;
#endif

        memset(&flags, 0, sizeof(flags));
        openlog("rrenumd", LOG_PID, LOG_DAEMON);

        /* get options */
        while ((ch = getopt(argc, argv, "c:sdf"
#ifdef IPSEC
#ifdef IPSEC_POLICY_IPSEC
                            "P:"
#else /* IPSEC_POLICY_IPSEC */
                            "AE"
#endif /* IPSEC_POLICY_IPSEC */
#endif /* IPSEC */
                            )) != -1){
                switch (ch) {
                case 'c':
                        if((fp = fopen(optarg, "r")) == NULL) {
                                syslog(LOG_ERR,
                                       "<%s> config file %s open failed",
                                       __func__, optarg);
                                exit(1);
                        }
                        break;
                case 's':
                        fp = stdin;
                        break;
                case 'd':
                        flags.debug = 1;
                        break;
                case 'f':
                        flags.fg = 1;
                        break;
#ifdef IPSEC
#ifdef IPSEC_POLICY_IPSEC
                case 'P':
                        flags.policy = 1;
                        policy = strdup(optarg);
                        break;
#else /* IPSEC_POLICY_IPSEC */
                case 'A':
                        flags.auth = 1;
                        break;
                case 'E':
                        flags.encrypt = 1;
                        break;
#endif /* IPSEC_POLICY_IPSEC */
#endif /*IPSEC*/
                default:
                        show_usage();
                }
        }
        argc -= optind;
        argv += optind;

        /* set log level */
        if (flags.debug == 0)
                (void)setlogmask(LOG_UPTO(LOG_ERR));
        if (flags.debug == 1)
                (void)setlogmask(LOG_UPTO(LOG_INFO));

        /* init global variables */
        init_globals();

        config(&fp);

        sock6_open(&flags
#ifdef IPSEC_POLICY_IPSEC
                   , policy
#endif /* IPSEC_POLICY_IPSEC */
                   );
        sock4_open(&flags
#ifdef IPSEC_POLICY_IPSEC
                   , policy
#endif /* IPSEC_POLICY_IPSEC */
                   );

        if (!flags.fg)
                daemon(0, 0);

        FD_ZERO(&fdset);
        if (with_v6dest) {
                FD_SET(s6, &fdset);
                if (s6 > maxfd)
                        maxfd = s6;
        }
        if (with_v4dest) {
                FD_SET(s4, &fdset);
                if (s4 > maxfd)
                        maxfd = s4;
        }

        /* ADHOC: timeout each 30seconds */
        memset(&timeout, 0, sizeof(timeout));

        /* init temporary payload_list and send_counter*/
        pl = pl_head;
        send_counter = retry + 1;
        while (1) {
                struct fd_set select_fd = fdset; /* reinitialize */

                if ((i = select(maxfd + 1, &select_fd, NULL, NULL,
                                &timeout)) < 0){
                        syslog(LOG_ERR, "<%s> select: %s",
                               __func__, strerror(errno));
                        continue;
                }
                if (i == 0) {   /* timeout */
                        if (pl == NULL)
                                exit(0);
                        rrenum_snd_eachdst(pl);
                        send_counter--;
                        timeout.tv_sec = 30;
                        if (send_counter == 0) {
                                timeout.tv_sec = 0;
                                pl = pl->pl_next;
                                send_counter = retry + 1;
                        }
                }
                if (FD_ISSET(s4, &select_fd))
                        rrenum_input(s4);
                if (FD_ISSET(s6, &select_fd))
                        rrenum_input(s6);
        }
}