* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.

/* $NetBSD: rtadvd.c,v 1.83 2025/02/26 04:49:46 andvar Exp $ */
/* $KAME: rtadvd.c,v 1.92 2005/10/17 14:40:02 suz Exp $ */

/*
* 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 <sys/queue.h>

#include <net/if.h>
#include <net/route.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>

#include <arpa/inet.h>

#include <time.h>
#include <unistd.h>
#include <stdio.h>
#include <err.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <signal.h>
#include <stdarg.h>
#ifdef __NetBSD__
#include <util.h>
#endif
#include <poll.h>
#include <pwd.h>

#include "rtadvd.h"
#include "advcap.h"
#include "timer.h"
#include "if.h"
#include "config.h"
#include "dump.h"
#include "logit.h"
#include "prog_ops.h"
#include "expandm.h"

struct msghdr rcvmhdr;
static unsigned char *rcvcmsgbuf;
static size_t rcvcmsgbuflen;
static unsigned char *sndcmsgbuf;
static size_t sndcmsgbuflen;
volatile sig_atomic_t do_dump;
volatile sig_atomic_t do_reconf;
volatile sig_atomic_t do_die;
struct msghdr sndmhdr;
struct iovec rcviov[2];
struct iovec sndiov[2];
struct sockaddr_in6 rcvfrom;
static const char *dumpfilename = "/var/run/rtadvd.dump"; /* XXX configurable */
int sock;
int rtsock = -1;
int Cflag = 0, dflag = 0, sflag = 0, Dflag;
static int after_daemon = 0;

static char **if_argv;
static int if_argc;

char *conffile = NULL;

struct ralist_head_t ralist = TAILQ_HEAD_INITIALIZER(ralist);

struct nd_optlist {
TAILQ_ENTRY(nd_optlist) next;
struct nd_opt_hdr *opt;
};
union nd_opts {
struct nd_opt_hdr *nd_opt_array[9];
struct {
struct nd_opt_hdr *zero;
struct nd_opt_hdr *src_lladdr;
struct nd_opt_hdr *tgt_lladdr;
struct nd_opt_prefix_info *pi;
struct nd_opt_rd_hdr *rh;
struct nd_opt_mtu *mtu;
TAILQ_HEAD(, nd_optlist) list;
} nd_opt_each;
};
#define nd_opts_src_lladdr nd_opt_each.src_lladdr
#define nd_opts_tgt_lladdr nd_opt_each.tgt_lladdr
#define nd_opts_pi nd_opt_each.pi
#define nd_opts_rh nd_opt_each.rh
#define nd_opts_mtu nd_opt_each.mtu
#define nd_opts_list nd_opt_each.list

#define NDOPT_FLAG_SRCLINKADDR (1 << 0)
#define NDOPT_FLAG_TGTLINKADDR (1 << 1)
#define NDOPT_FLAG_PREFIXINFO (1 << 2)
#define NDOPT_FLAG_RDHDR (1 << 3)
#define NDOPT_FLAG_MTU (1 << 4)
#define NDOPT_FLAG_RDNSS (1 << 5)
#define NDOPT_FLAG_DNSSL (1 << 6)

uint32_t ndopt_flags[] = {
[ND_OPT_SOURCE_LINKADDR] = NDOPT_FLAG_SRCLINKADDR,
[ND_OPT_TARGET_LINKADDR] = NDOPT_FLAG_TGTLINKADDR,
[ND_OPT_PREFIX_INFORMATION] = NDOPT_FLAG_PREFIXINFO,
[ND_OPT_REDIRECTED_HEADER] = NDOPT_FLAG_RDHDR,
[ND_OPT_MTU] = NDOPT_FLAG_MTU,
[ND_OPT_RDNSS] = NDOPT_FLAG_RDNSS,
[ND_OPT_DNSSL] = NDOPT_FLAG_DNSSL,
};

struct sockaddr_in6 sin6_linklocal_allnodes = {
.sin6_len = sizeof(sin6_linklocal_allnodes),
.sin6_family = AF_INET6,
.sin6_addr = IN6ADDR_LINKLOCAL_ALLNODES_INIT,
};
#ifdef notdef
struct sockaddr_in6 sin6_linklocal_allrouters = {
.sin6_len = sizeof(sin6_linklocal_allrouters),
.sin6_family = AF_INET6,
.sin6_addr = IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
};
#endif
struct sockaddr_in6 sin6_sitelocal_allrouters = {
.sin6_len = sizeof(sin6_sitelocal_allrouters),
.sin6_family = AF_INET6,
.sin6_addr = IN6ADDR_SITELOCAL_ALLROUTERS_INIT,
};

static void set_die(int);
static void die(void);
static void set_reconf(int);
static void sock_open(void);
static void rtsock_open(void);
static void rtadvd_input(void);
static void rs_input(int, struct nd_router_solicit *,
struct in6_pktinfo *, struct sockaddr_in6 *);
static void ra_input(int, struct nd_router_advert *,
struct in6_pktinfo *, struct sockaddr_in6 *);
static struct rainfo *ra_output(struct rainfo *, bool);
static int prefix_check(struct nd_opt_prefix_info *, struct rainfo *,
struct sockaddr_in6 *);
static int nd6_options(struct nd_opt_hdr *, int, union nd_opts *, uint32_t);
static void free_ndopts(union nd_opts *);
static void rtmsg_input(void);
static void rtadvd_set_dump_file(int);

int
main(int argc, char *argv[])
{
struct pollfd set[2];
struct timespec *timeout;
int i, ch;
int fflag = 0, logopt;
struct passwd *pw;
const char *pidfilepath = NULL;
pid_t pid;

/* get command line options and arguments */
#define OPTIONS "Cc:dDfp:s"
while ((ch = getopt(argc, argv, OPTIONS)) != -1) {
#undef OPTIONS
switch (ch) {
case 'c':
conffile = optarg;
break;
case 'C':
Cflag++;
break;
case 'd':
dflag++;
break;
case 'D':
Dflag++;
break;
case 'f':
fflag = 1;
break;
case 'p':
pidfilepath = optarg;
break;
case 's':
sflag = 1;
break;
}
}
argc -= optind;
argv += optind;
if (argc == 0) {
fprintf(stderr, "Usage: %s [-CDdfs] [-c conffile]"
" [-p pidfile] interface ...\n", getprogname());
return EXIT_FAILURE;
}

if ((pid = pidfile_lock(pidfilepath)) != 0) {
if (pid == -1) {
logit(LOG_ERR, "pidfile_lock: %m");
} else {
logit(LOG_ERR, "Another instance of `%s' is running "
"(pid %d); exiting.", getprogname(), pid);
}
return EXIT_FAILURE;
}

if (prog_init && prog_init() == -1)
err(EXIT_FAILURE, "init failed");

logopt = LOG_NDELAY | LOG_PID;
if (fflag)
logopt |= LOG_PERROR;
openlog("rtadvd", logopt, LOG_DAEMON);

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

errno = 0; /* Ensure errno is 0 so we know if getpwnam errors or not */
if ((pw = getpwnam(RTADVD_USER)) == NULL) {
if (errno == 0)
logit(LOG_ERR,
"user %s does not exist, aborting",
RTADVD_USER);
else
logit(LOG_ERR, "getpwnam: %s: %m", RTADVD_USER);
return EXIT_FAILURE;
}

/* timer initialization */
rtadvd_timer_init();

if_argc = argc;
if_argv = argv;
while (argc--)
getconfig(*argv++, 1);

if (!fflag) {
prog_daemon(1, 0);
after_daemon = 1;
if (pidfile_lock(pidfilepath) != 0)
logit(LOG_ERR, " pidfile_lock: %m");
}

sock_open();

set[0].fd = sock;
set[0].events = POLLIN;
if (sflag == 0) {
rtsock_open();
set[1].fd = rtsock;
set[1].events = POLLIN;
} else
set[1].fd = -1;

logit(LOG_INFO, "dropping privileges to %s", RTADVD_USER);
tzset();
if (prog_chroot(pw->pw_dir) == -1) {
logit(LOG_ERR, "chroot: %s: %m", pw->pw_dir);
return EXIT_FAILURE;
}
if (prog_chdir("/") == -1) {
logit(LOG_ERR, "chdir: /: %m");
return EXIT_FAILURE;
}
if (prog_setgroups(1, &pw->pw_gid) == -1 ||
prog_setgid(pw->pw_gid) == -1 ||
prog_setuid(pw->pw_uid) == -1)
{
logit(LOG_ERR, "failed to drop privileges: %m");
return EXIT_FAILURE;
}

signal(SIGINT, set_die);
signal(SIGTERM, set_die);
signal(SIGHUP, set_reconf);
signal(SIGUSR1, rtadvd_set_dump_file);

for (;;) {
if (do_dump) { /* SIGUSR1 */
do_dump = 0;
rtadvd_dump_file(dumpfilename);
}

if (do_reconf) { /* SIGHUP */
do_reconf = 0;
logit(LOG_INFO, "%s: reloading config on SIGHUP",
__func__);
argc = if_argc;
argv = if_argv;
while (argc--)
getconfig(*argv++, 0);
}

/* timer expiration check and reset the timer */
timeout = rtadvd_check_timer();

if (do_die) {
die();
/*NOTREACHED*/
}

if (timeout != NULL) {
logit(LOG_DEBUG,
"%s: set timer to %jd:%jd. waiting for "
"inputs or timeout", __func__,
(intmax_t)timeout->tv_sec,
(intmax_t)timeout->tv_nsec);
} else {
logit(LOG_DEBUG,
"%s: there's no timer. waiting for inputs",
__func__);
}

if ((i = prog_poll(set, 2, timeout ? (timeout->tv_sec * 1000 +
(timeout->tv_nsec + 999999) / 1000000) : INFTIM)) == -1)
{
/* EINTR would occur upon SIGUSR1 for status dump */
if (errno == EINTR) {
if (do_die)
die();
continue;
}

logit(LOG_ERR, "%s: poll: %m", __func__);
if (Dflag)
exit(1);
}
if (i == 0) /* timeout */
continue;
if (rtsock != -1 && set[1].revents & POLLIN)
rtmsg_input();
if (set[0].revents & POLLIN)
rtadvd_input();
}
return EXIT_SUCCESS; /* NOTREACHED */
}

static void
rtadvd_set_dump_file(__unused int sig)
{

do_dump = 1;
}

static void
set_reconf(__unused int sig)
{

do_reconf = 1;
}

static void
set_die(__unused int sig)
{

do_die = 1;
}

static void
die(void)
{
static int waiting;
struct rainfo *rai, *ran;
struct rdnss *rdnss;
struct dnssl *dnssl;

if (waiting) {
if (TAILQ_FIRST(&ralist)) {
logit(LOG_INFO,
"%s: waiting for expiration of all RA timers",
__func__);
return;
}
logit(LOG_NOTICE, "%s: gracefully terminated", __func__);
free(rcvcmsgbuf);
free(sndcmsgbuf);
exit(EXIT_SUCCESS);
/* NOT REACHED */
}

if (TAILQ_FIRST(&ralist) == NULL) {
logit(LOG_NOTICE, "%s: gracefully terminated", __func__);
exit(EXIT_SUCCESS);
/* NOT REACHED */
}

waiting = 1;
logit(LOG_NOTICE, "%s: final RA transmission started", __func__);

TAILQ_FOREACH_SAFE(rai, &ralist, next, ran) {
if (rai->leaving) {
TAILQ_REMOVE(&ralist, rai, next);
TAILQ_INSERT_HEAD(&ralist, rai->leaving, next);
rai->leaving->leaving = rai->leaving;
rai->leaving->leaving_for = rai->leaving;
free_rainfo(rai);
continue;
}
rai->lifetime = 0;
TAILQ_FOREACH(rdnss, &rai->rdnss, next)
rdnss->lifetime = 0;
TAILQ_FOREACH(dnssl, &rai->dnssl, next)
dnssl->lifetime = 0;
make_packet(rai);
rai->leaving = rai;
rai->leaving_for = rai;
rai->initcounter = MAX_INITIAL_RTR_ADVERTISEMENTS;
rai->mininterval = MIN_DELAY_BETWEEN_RAS;
rai->maxinterval = MIN_DELAY_BETWEEN_RAS;
rai->leaving_adv = MAX_FINAL_RTR_ADVERTISEMENTS;
ra_output(rai, false);
ra_timer_update(rai, &rai->timer->tm);
rtadvd_set_timer(&rai->timer->tm, rai->timer);
}
exit(EXIT_SUCCESS);
}

static void
ra_timer_reset(struct rainfo *rai)
{

rtadvd_remove_timer(&rai->timer);
rai->timer = rtadvd_add_timer(ra_timeout, ra_timer_update, rai, rai);
ra_timer_update(rai, &rai->timer->tm);
rtadvd_set_timer(&rai->timer->tm, rai->timer);
rtadvd_remove_timer(&rai->timer_sol);
rai->timer_sol = rtadvd_add_timer(ra_timeout_sol, NULL, rai, NULL);
}

static void
rtmsg_input(void)
{
int n, type, ifindex = 0, plen;
size_t len;
union rt_msghdr_buf {
struct rt_msghdr rt_msghdr;
char data[2048];
} buffer;
char *msg, *next, *lim, **argv;
char ifname[IF_NAMESIZE];
struct prefix *prefix;
struct rainfo *rai;
const struct in6_addr *addr;
char addrbuf[INET6_ADDRSTRLEN];
int prefixchange = 0, argc;

memset(&buffer, 0, sizeof(buffer));
n = prog_read(rtsock, &buffer, sizeof(buffer));

/* We read the buffer first to clear the FD */
if (do_die)
return;

msg = buffer.data;
if (dflag > 1) {
logit(LOG_DEBUG, "%s: received a routing message "
"(type = %d [%s], len = %d)", __func__, rtmsg_type(msg),
rtmsg_typestr(msg), rtmsg_len(msg));
}
if (n > rtmsg_len(msg)) {
/*
* This usually won't happen for messages received on
* a routing socket.
*/
if (dflag > 1)
logit(LOG_DEBUG,
"%s: received data length is larger than "
"1st routing message len. multiple messages? "
"read %d bytes, but 1st msg len = %d",
__func__, n, rtmsg_len(msg));
#if 0
/* adjust length */
n = rtmsg_len(msg);
#endif
}

lim = msg + n;
for (next = msg; next < lim; next += len) {
int oldifflags;

next = get_next_msg(next, lim, 0, &len,
RTADV_TYPE2BITMASK(RTM_ADD) |
RTADV_TYPE2BITMASK(RTM_DELETE) |
RTADV_TYPE2BITMASK(RTM_NEWADDR) |
RTADV_TYPE2BITMASK(RTM_DELADDR) |
#ifdef RTM_IFANNOUNCE
RTADV_TYPE2BITMASK(RTM_IFANNOUNCE) |
#endif
RTADV_TYPE2BITMASK(RTM_IFINFO));
if (len == 0)
break;
type = rtmsg_type(next);
switch (type) {
case RTM_ADD:
case RTM_DELETE:
ifindex = get_rtm_ifindex(next);
break;
case RTM_NEWADDR:
case RTM_DELADDR:
ifindex = get_ifam_ifindex(next);
break;
#ifdef RTM_IFANNOUNCE
case RTM_IFANNOUNCE:
ifindex = get_ifan_ifindex(next);
if (get_ifan_what(next) == IFAN_ARRIVAL) {
logit(LOG_DEBUG,
"%s: interface %s arrived",
__func__,
if_indextoname(ifindex, ifname));
if (if_argc == 0) {
getconfig(ifname, 0);
continue;
}
argc = if_argc;
argv = if_argv;
while (argc--) {
if (strcmp(ifname, *argv++) == 0) {
getconfig(ifname, 0);
break;
}
}
continue;
}
break;
#endif
case RTM_IFINFO:
ifindex = get_ifm_ifindex(next);
break;
default:
/* should not reach here */
if (dflag > 1) {
logit(LOG_DEBUG, "%s: unknown rtmsg %d on %s",
__func__, type,
if_indextoname(ifindex, ifname));
}
continue;
}

if ((rai = if_indextorainfo(ifindex)) == NULL) {
if (dflag > 1) {
logit(LOG_DEBUG,
"%s: route changed on "
"non advertising interface %s (%d)",
__func__,
if_indextoname(ifindex, ifname),
ifindex);
}
continue;
}
oldifflags = rai->ifflags;

switch (type) {
case RTM_ADD:
/* init ifflags because it may have changed */
rai->ifflags = if_getflags(ifindex, rai->ifflags);

if (sflag)
break; /* we aren't interested in prefixes */

addr = get_addr(msg);
plen = get_prefixlen(msg);
/* sanity check for plen */
/* as RFC2373, prefixlen is at least 4 */
if (plen < 4 || plen > 127) {
logit(LOG_INFO, "%s: new interface route's"
"plen %d is invalid for a prefix",
__func__, plen);
break;
}
prefix = find_prefix(rai, addr, plen);
if (prefix) {
if (prefix->timer) {
/*
* If the prefix has been invalidated,
* make it available again.
*/
update_prefix(prefix);
prefixchange = 1;
} else if (dflag > 1) {
logit(LOG_DEBUG,
"%s: new prefix(%s/%d) "
"added on %s, "
"but it was already in list",
__func__,
inet_ntop(AF_INET6, addr,
(char *)addrbuf, INET6_ADDRSTRLEN),
plen, rai->ifname);
}
break;
}
add_prefix(rai, ifindex, addr, plen);
prefixchange = 1;
break;
case RTM_DELETE:
/* init ifflags because it may have changed */
rai->ifflags = if_getflags(ifindex, rai->ifflags);

if (sflag)
break;

addr = get_addr(msg);
plen = get_prefixlen(msg);
/* sanity check for plen */
/* as RFC2373, prefixlen is at least 4 */
if (plen < 4 || plen > 127) {
logit(LOG_INFO,
"%s: deleted interface route's "
"plen %d is invalid for a prefix",
__func__, plen);
break;
}
prefix = find_prefix(rai, addr, plen);
if (prefix == NULL) {
if (dflag > 1) {
logit(LOG_DEBUG,
"%s: prefix(%s/%d) was "
"deleted on %s, "
"but it was not in list",
__func__,
inet_ntop(AF_INET6, addr,
(char *)addrbuf, INET6_ADDRSTRLEN),
plen, rai->ifname);
}
break;
}
invalidate_prefix(prefix);
prefixchange = 1;
break;
case RTM_NEWADDR:
case RTM_DELADDR:
/* init ifflags because it may have changed */
rai->ifflags = if_getflags(ifindex, rai->ifflags);
break;
case RTM_IFINFO:
rai->ifflags = get_ifm_flags(next);
break;
#ifdef RTM_IFANNOUNCE
case RTM_IFANNOUNCE:
if (get_ifan_what(next) == IFAN_DEPARTURE) {
logit(LOG_DEBUG,
"%s: interface %s departed",
__func__, rai->ifname);
TAILQ_REMOVE(&ralist, rai, next);
if (rai->leaving)
free_rainfo(rai->leaving);
free_rainfo(rai);
continue;
}
break;
#endif
default:
/* should not reach here */
if (dflag > 1) {
logit(LOG_DEBUG,
"%s: unknown rtmsg %d on %s",
__func__, type,
if_indextoname(ifindex, ifname));
}
return;
}

/* check if an interface flag is changed */
if ((oldifflags & IFF_UP) != 0 && /* UP to DOWN */
(rai->ifflags & IFF_UP) == 0) {
logit(LOG_INFO,
"%s: interface %s becomes down. stop timer.",
__func__, rai->ifname);
rtadvd_remove_timer(&rai->timer);
} else if ((oldifflags & IFF_UP) == 0 && /* DOWN to UP */
(rai->ifflags & IFF_UP) != 0) {
logit(LOG_INFO,
"%s: interface %s becomes up. restart timer.",
__func__, rai->ifname);

rai->initcounter = 0; /* reset the counter */
rai->waiting = 0; /* XXX */
ra_timer_reset(rai);
} else if (prefixchange && rai->ifflags & IFF_UP) {
/*
* An advertised prefix has been added or invalidated.
* Will notice the change in a short delay.
*/
rai->initcounter = 0;
ra_timer_set_short_delay(rai, rai->timer);
}
}

return;
}

void
rtadvd_input(void)
{
ssize_t i;
int *hlimp = NULL;
struct icmp6_hdr *icp;
int ifindex = 0;
struct cmsghdr *cm;
struct in6_pktinfo *pi = NULL;
char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
struct rainfo *rai;

/*
* Get message. We reset msg_controllen since the field could
* be modified if we had received a message before setting
* receive options.
*/
rcvmhdr.msg_controllen = rcvcmsgbuflen;
if ((i = prog_recvmsg(sock, &rcvmhdr, 0)) == -1)
return;

/* We read the buffer first to clear the FD */
if (do_die)
return;

/* extract optional information via Advanced API */
for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&rcvmhdr);
cm;
cm = (struct cmsghdr *)CMSG_NXTHDR(&rcvmhdr, cm)) {
if (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));
ifindex = pi->ipi6_ifindex;
}
if (cm->cmsg_level == IPPROTO_IPV6 &&
cm->cmsg_type == IPV6_HOPLIMIT &&
cm->cmsg_len == CMSG_LEN(sizeof(int)))
hlimp = (int *)CMSG_DATA(cm);
}
if (ifindex == 0) {
logit(LOG_ERR,
"%s: failed to get receiving interface",
__func__);
return;
}
if (hlimp == NULL) {
logit(LOG_ERR,
"%s: failed to get receiving hop limit",
__func__);
return;
}

if ((rai = if_indextorainfo(pi->ipi6_ifindex)) == NULL) {
if (dflag > 1) {
logit(LOG_DEBUG,
"%s: received data for non advertising "
"interface (%s)",
__func__,
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
}
return;
}
/*
* If we happen to receive data on an interface which is now down,
* just discard the data.
*/
if ((rai->ifflags & IFF_UP) == 0) {
logit(LOG_INFO,
"%s: received data on a disabled interface (%s)",
__func__,
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}

if ((size_t)i < sizeof(struct icmp6_hdr)) {
logit(LOG_ERR,
"%s: packet size(%zd) is too short",
__func__, i);
return;
}

icp = (struct icmp6_hdr *)rcvmhdr.msg_iov[0].iov_base;

switch (icp->icmp6_type) {
case ND_ROUTER_SOLICIT:
/*
* Message verification - RFC-2461 6.1.1
* XXX: these checks must be done in the kernel as well,
* but we can't completely rely on them.
*/
if (*hlimp != 255) {
logit(LOG_NOTICE,
"%s: RS with invalid hop limit(%d) "
"received from %s on %s",
__func__, *hlimp,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if (icp->icmp6_code) {
logit(LOG_NOTICE,
"%s: RS with invalid ICMP6 code(%d) "
"received from %s on %s",
__func__, icp->icmp6_code,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if ((size_t)i < sizeof(struct nd_router_solicit)) {
logit(LOG_NOTICE,
"%s: RS from %s on %s does not have enough "
"length (len = %zd)",
__func__,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf), i);
return;
}
rs_input(i, (struct nd_router_solicit *)icp, pi, &rcvfrom);
break;
case ND_ROUTER_ADVERT:
/*
* Message verification - RFC-2461 6.1.2
* XXX: there's a same dilemma as above...
*/
if (*hlimp != 255) {
logit(LOG_NOTICE,
"%s: RA with invalid hop limit(%d) "
"received from %s on %s",
__func__, *hlimp,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if (icp->icmp6_code) {
logit(LOG_NOTICE,
"%s: RA with invalid ICMP6 code(%d) "
"received from %s on %s",
__func__, icp->icmp6_code,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if ((size_t)i < sizeof(struct nd_router_advert)) {
logit(LOG_NOTICE,
"%s: RA from %s on %s does not have enough "
"length (len = %zd)",
__func__,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf), i);
return;
}
ra_input(i, (struct nd_router_advert *)icp, pi, &rcvfrom);
break;
default:
/*
* Note that this case is POSSIBLE, especially just
* after invocation of the daemon. This is because we
* could receive message after opening the socket and
* before setting ICMP6 type filter(see sock_open()).
*/
logit(LOG_ERR, "%s: invalid icmp type(%d)",
__func__, icp->icmp6_type);
return;
}
}

static void
rs_input(int len, struct nd_router_solicit *rs,
struct in6_pktinfo *pi, struct sockaddr_in6 *from)
{
char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
union nd_opts ndopts;
struct rainfo *rai;
struct soliciter *sol;

logit(LOG_DEBUG,
"%s: RS received from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));

/* ND option check */
memset(&ndopts, 0, sizeof(ndopts));
TAILQ_INIT(&ndopts.nd_opts_list);
if (nd6_options((struct nd_opt_hdr *)(rs + 1),
len - sizeof(struct nd_router_solicit),
&ndopts, NDOPT_FLAG_SRCLINKADDR)) {
logit(LOG_INFO,
"%s: ND option check failed for an RS from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}

/*
* If the IP source address is the unspecified address, there
* must be no source link-layer address option in the message.
* (RFC-2461 6.1.1)
*/
if (IN6_IS_ADDR_UNSPECIFIED(&from->sin6_addr) &&
ndopts.nd_opts_src_lladdr) {
logit(LOG_INFO,
"%s: RS from unspecified src on %s has a link-layer"
" address option",
__func__,
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
goto done;
}

if ((rai = if_indextorainfo(pi->ipi6_ifindex)) == NULL) {
logit(LOG_INFO,
"%s: RS received on non advertising interface(%s)",
__func__,
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
goto done;
}

if (rai->leaving) {
logit(LOG_INFO,
"%s: RS received on reconfiguring advertising interface(%s)",
__func__, rai->ifname);
goto done;
}

rai->rsinput++; /* increment statistics */

/*
* Decide whether to send RA according to the rate-limit
* consideration.
*/

/* record sockaddr waiting for RA, if possible */
TAILQ_FOREACH(sol, &rai->soliciter, next) {
if (IN6_ARE_ADDR_EQUAL(&sol->addr.sin6_addr, &from->sin6_addr))
break;
}
if (sol == NULL) {
sol = malloc(sizeof(*sol));
if (sol == NULL) {
logit(LOG_ERR, "%s: malloc: %m", __func__);
} else {
sol->addr = *from;
/* XXX RFC2553 need clarification on flowinfo */
sol->addr.sin6_flowinfo = 0;
TAILQ_INSERT_TAIL(&rai->soliciter, sol, next);
}
}

/*
* If there is already a waiting RS packet, don't
* update the timer.
*/
if (rai->waiting++)
goto done;

ra_timer_set_short_delay(rai, rai->timer_sol);

done:
free_ndopts(&ndopts);
}

void
ra_timer_set_short_delay(struct rainfo *rai, struct rtadvd_timer *timer)
{
long delay; /* must not be greater than 1000000 */
struct timespec interval, now, min_delay, tm_tmp, *rest;

/*
* Compute a random delay. If the computed value
* corresponds to a time later than the time the next
* multicast RA is scheduled to be sent, ignore the random
* delay and send the advertisement at the
* already-scheduled time. RFC2461 6.2.6
*/
delay = arc4random() % MAX_RA_DELAY_TIME;
interval.tv_sec = 0;
interval.tv_nsec = delay;
rest = rtadvd_timer_rest(rai->timer);
if (timespeccmp(rest, &interval, <)) {
logit(LOG_DEBUG, "%s: random delay is larger than "
"the rest of current timer", __func__);
interval = *rest;
}

/*
* If we sent a multicast Router Advertisement within
* the last MIN_DELAY_BETWEEN_RAS seconds, schedule
* the advertisement to be sent at a time corresponding to
* MIN_DELAY_BETWEEN_RAS plus the random value after the
* previous advertisement was sent.
*/
prog_clock_gettime(CLOCK_MONOTONIC, &now);
timespecsub(&now, &rai->lastsent, &tm_tmp);
min_delay.tv_sec = MIN_DELAY_BETWEEN_RAS;
min_delay.tv_nsec = 0;
if (timespeccmp(&tm_tmp, &min_delay, <)) {
timespecsub(&min_delay, &tm_tmp, &min_delay);
timespecadd(&min_delay, &interval, &interval);
}
rtadvd_set_timer(&interval, timer);
}

static void
ra_input(int len, struct nd_router_advert *ra,
struct in6_pktinfo *pi, struct sockaddr_in6 *from)
{
struct rainfo *rai;
char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
union nd_opts ndopts;
const char *on_off[] = {"OFF", "ON"};
uint32_t reachabletime, retranstimer, mtu;
struct nd_optlist *optp;
int inconsistent = 0;

logit(LOG_DEBUG,
"%s: RA received from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));

/* ND option check */
memset(&ndopts, 0, sizeof(ndopts));
TAILQ_INIT(&ndopts.nd_opts_list);
if (nd6_options((struct nd_opt_hdr *)(ra + 1),
len - sizeof(struct nd_router_advert),
&ndopts, NDOPT_FLAG_SRCLINKADDR |
NDOPT_FLAG_PREFIXINFO | NDOPT_FLAG_MTU |
NDOPT_FLAG_RDNSS | NDOPT_FLAG_DNSSL))
{
logit(LOG_INFO,
"%s: ND option check failed for an RA from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}

/*
* RA consistency check according to RFC-2461 6.2.7
*/
if ((rai = if_indextorainfo(pi->ipi6_ifindex)) == 0) {
logit(LOG_INFO,
"%s: received RA from %s on non-advertising"
" interface(%s)",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
goto done;
}
if (rai->leaving) {
logit(LOG_DEBUG,
"%s: received RA on re-configuring interface (%s)",
__func__, rai->ifname);
goto done;
}
rai->rainput++; /* increment statistics */

/* Cur Hop Limit value */
if (ra->nd_ra_curhoplimit && rai->hoplimit &&
ra->nd_ra_curhoplimit != rai->hoplimit) {
logit(LOG_INFO,
"%s: CurHopLimit inconsistent on %s:"
" %d from %s, %d from us",
__func__,
rai->ifname,
ra->nd_ra_curhoplimit,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
rai->hoplimit);
inconsistent++;
}
/* M flag */
if ((ra->nd_ra_flags_reserved & ND_RA_FLAG_MANAGED) !=
rai->managedflg) {
logit(LOG_INFO,
"%s: M flag inconsistent on %s:"
" %s from %s, %s from us",
__func__,
rai->ifname,
on_off[!rai->managedflg],
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
on_off[rai->managedflg]);
inconsistent++;
}
/* O flag */
if ((ra->nd_ra_flags_reserved & ND_RA_FLAG_OTHER) !=
rai->otherflg) {
logit(LOG_INFO,
"%s: O flag inconsistent on %s:"
" %s from %s, %s from us",
__func__,
rai->ifname,
on_off[!rai->otherflg],
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
on_off[rai->otherflg]);
inconsistent++;
}
/* Reachable Time */
reachabletime = ntohl(ra->nd_ra_reachable);
if (reachabletime && rai->reachabletime &&
reachabletime != rai->reachabletime) {
logit(LOG_INFO,
"%s: ReachableTime inconsistent on %s:"
" %d from %s, %d from us",
__func__,
rai->ifname,
reachabletime,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
rai->reachabletime);
inconsistent++;
}
/* Retrans Timer */
retranstimer = ntohl(ra->nd_ra_retransmit);
if (retranstimer && rai->retranstimer &&
retranstimer != rai->retranstimer) {
logit(LOG_INFO,
"%s: RetranceTimer inconsistent on %s:"
" %d from %s, %d from us",
__func__,
rai->ifname,
retranstimer,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
rai->retranstimer);
inconsistent++;
}
/* Values in the MTU options */
if (ndopts.nd_opts_mtu) {
mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
if (mtu && rai->linkmtu && mtu != rai->linkmtu) {
logit(LOG_INFO,
"%s: MTU option value inconsistent on %s:"
" %d from %s, %d from us",
__func__,
rai->ifname, mtu,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
rai->linkmtu);
inconsistent++;
}
}
/* Preferred and Valid Lifetimes for prefixes */
if (ndopts.nd_opts_pi)
if (prefix_check(ndopts.nd_opts_pi, rai, from))
inconsistent++;
TAILQ_FOREACH(optp, &ndopts.nd_opts_list, next)
if (prefix_check((struct nd_opt_prefix_info *)optp->opt,
rai, from))
inconsistent++;

if (inconsistent)
rai->rainconsistent++;

done:
free_ndopts(&ndopts);
}

/* return a non-zero value if the received prefix is inconsitent with ours */
static int
prefix_check(struct nd_opt_prefix_info *pinfo,
struct rainfo *rai, struct sockaddr_in6 *from)
{
uint32_t preferred_time, valid_time;
struct prefix *pp;
int inconsistent = 0;
char ntopbuf[INET6_ADDRSTRLEN], prefixbuf[INET6_ADDRSTRLEN];
struct timespec now;
struct in6_addr prefix;

#if 0 /* impossible */
if (pinfo->nd_opt_pi_type != ND_OPT_PREFIX_INFORMATION)
return 0;
#endif

memcpy(&prefix, &pinfo->nd_opt_pi_prefix, sizeof(prefix));

/*
* log if the adveritsed prefix has link-local scope(sanity check?)
*/
if (IN6_IS_ADDR_LINKLOCAL(&prefix)) {
logit(LOG_INFO,
"%s: link-local prefix %s/%d is advertised "
"from %s on %s",
__func__,
inet_ntop(AF_INET6, &prefix,
prefixbuf, INET6_ADDRSTRLEN),
pinfo->nd_opt_pi_prefix_len,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
rai->ifname);
}

if ((pp = find_prefix(rai, &prefix,
pinfo->nd_opt_pi_prefix_len)) == NULL) {
logit(LOG_INFO,
"%s: prefix %s/%d from %s on %s is not in our list",
__func__,
inet_ntop(AF_INET6, &prefix,
prefixbuf, INET6_ADDRSTRLEN),
pinfo->nd_opt_pi_prefix_len,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
rai->ifname);
return 0;
}

preferred_time = ntohl(pinfo->nd_opt_pi_preferred_time);
if (pp->pltimeexpire) {
/*
* The lifetime is decremented in real time, so we should
* compare the expiration time.
* (RFC 2461 Section 6.2.7.)
* XXX: can we really expect that all routers on the link
* have synchronized clocks?
*/
prog_clock_gettime(CLOCK_MONOTONIC, &now);
preferred_time += now.tv_sec;

if (!pp->timer && rai->clockskew &&
llabs((long long)preferred_time - pp->pltimeexpire) > rai->clockskew) {
logit(LOG_INFO,
"%s: preferred lifetime for %s/%d"
" (decr. in real time) inconsistent on %s:"
" %d from %s, %ld from us",
__func__,
inet_ntop(AF_INET6, &prefix,
prefixbuf, INET6_ADDRSTRLEN),
pinfo->nd_opt_pi_prefix_len,
rai->ifname, preferred_time,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
pp->pltimeexpire);
inconsistent++;
}
} else if (!pp->timer && preferred_time != pp->preflifetime) {
logit(LOG_INFO,
"%s: preferred lifetime for %s/%d"
" inconsistent on %s:"
" %d from %s, %d from us",
__func__,
inet_ntop(AF_INET6, &prefix,
prefixbuf, INET6_ADDRSTRLEN),
pinfo->nd_opt_pi_prefix_len,
rai->ifname, preferred_time,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
pp->preflifetime);
}

valid_time = ntohl(pinfo->nd_opt_pi_valid_time);
if (pp->vltimeexpire) {
prog_clock_gettime(CLOCK_MONOTONIC, &now);
valid_time += now.tv_sec;

if (!pp->timer && rai->clockskew &&
llabs((long long)valid_time - pp->vltimeexpire) > rai->clockskew) {
logit(LOG_INFO,
"%s: valid lifetime for %s/%d"
" (decr. in real time) inconsistent on %s:"
" %d from %s, %ld from us",
__func__,
inet_ntop(AF_INET6, &prefix,
prefixbuf, INET6_ADDRSTRLEN),
pinfo->nd_opt_pi_prefix_len,
rai->ifname, preferred_time,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
pp->vltimeexpire);
inconsistent++;
}
} else if (!pp->timer && valid_time != pp->validlifetime) {
logit(LOG_INFO,
"%s: valid lifetime for %s/%d"
" inconsistent on %s:"
" %d from %s, %d from us",
__func__,
inet_ntop(AF_INET6, &prefix,
prefixbuf, INET6_ADDRSTRLEN),
pinfo->nd_opt_pi_prefix_len,
rai->ifname, valid_time,
inet_ntop(AF_INET6, &from->sin6_addr,
ntopbuf, INET6_ADDRSTRLEN),
pp->validlifetime);
inconsistent++;
}

return inconsistent;
}

struct prefix *
find_prefix(struct rainfo *rai, const struct in6_addr *prefix, int plen)
{
struct prefix *pp;
int bytelen, bitlen;
unsigned char bitmask;

TAILQ_FOREACH(pp, &rai->prefix, next) {
if (plen != pp->prefixlen)
continue;
bytelen = plen / 8;
bitlen = plen % 8;
bitmask = 0xff << (8 - bitlen);
if (memcmp(prefix, &pp->prefix, bytelen))
continue;
if (bitlen == 0 ||
((prefix->s6_addr[bytelen] & bitmask) ==
(pp->prefix.s6_addr[bytelen] & bitmask))) {
return pp;
}
}

return NULL;
}

/* check if p0/plen0 matches p1/plen1; return 1 if matches, otherwise 0. */
int
prefix_match(struct in6_addr *p0, int plen0,
struct in6_addr *p1, int plen1)
{
int bytelen, bitlen;
unsigned char bitmask;

if (plen0 < plen1)
return 0;
bytelen = plen1 / 8;
bitlen = plen1 % 8;
bitmask = 0xff << (8 - bitlen);
if (memcmp(p0, p1, bytelen))
return 0;
if (bitlen == 0 ||
((p0->s6_addr[bytelen] & bitmask) ==
(p1->s6_addr[bytelen] & bitmask))) {
return 1;
}

return 0;
}

static int
nd6_options(struct nd_opt_hdr *hdr, int limit,
union nd_opts *ndopts, uint32_t optflags)
{
int optlen = 0;

for (; limit > 0; limit -= optlen) {
if ((size_t)limit < sizeof(struct nd_opt_hdr)) {
logit(LOG_INFO, "%s: short option header", __func__);
goto bad;
}

hdr = (struct nd_opt_hdr *)((char *)hdr + optlen);
if (hdr->nd_opt_len == 0) {
logit(LOG_INFO,
"%s: bad ND option length(0) (type = %d)",
__func__, hdr->nd_opt_type);
goto bad;
}
optlen = hdr->nd_opt_len << 3;
if (optlen > limit) {
logit(LOG_INFO, "%s: short option", __func__);
goto bad;
}

if (hdr->nd_opt_type > ND_OPT_MTU &&
hdr->nd_opt_type != ND_OPT_RDNSS &&
hdr->nd_opt_type != ND_OPT_DNSSL)
{
logit(LOG_INFO, "%s: unknown ND option(type %d)",
__func__, hdr->nd_opt_type);
continue;
}

if ((ndopt_flags[hdr->nd_opt_type] & optflags) == 0) {
logit(LOG_INFO, "%s: unexpected ND option(type %d)",
__func__, hdr->nd_opt_type);
continue;
}

/*
* Option length check. Do it here for all fixed-length
* options.
*/
if ((hdr->nd_opt_type == ND_OPT_MTU &&
(optlen != sizeof(struct nd_opt_mtu))) ||
((hdr->nd_opt_type == ND_OPT_PREFIX_INFORMATION &&
optlen != sizeof(struct nd_opt_prefix_info))) ||
(hdr->nd_opt_type == ND_OPT_RDNSS &&
((optlen < (int)sizeof(struct nd_opt_rdnss) ||
(optlen - sizeof(struct nd_opt_rdnss)) % 16 != 0))) ||
(hdr->nd_opt_type == ND_OPT_DNSSL &&
optlen < (int)sizeof(struct nd_opt_dnssl)))
{
logit(LOG_INFO, "%s: invalid option length",
__func__);
continue;
}

switch (hdr->nd_opt_type) {
case ND_OPT_TARGET_LINKADDR:
case ND_OPT_REDIRECTED_HEADER:
case ND_OPT_RDNSS:
case ND_OPT_DNSSL:
break; /* we don't care about these options */
case ND_OPT_SOURCE_LINKADDR:
case ND_OPT_MTU:
if (ndopts->nd_opt_array[hdr->nd_opt_type]) {
logit(LOG_INFO,
"%s: duplicated ND option (type = %d)",
__func__, hdr->nd_opt_type);
}
ndopts->nd_opt_array[hdr->nd_opt_type] = hdr;
break;
case ND_OPT_PREFIX_INFORMATION:
{
struct nd_optlist *pfxlist;

if (ndopts->nd_opts_pi == 0) {
ndopts->nd_opts_pi =
(struct nd_opt_prefix_info *)hdr;
continue;
}
if ((pfxlist = malloc(sizeof(*pfxlist))) == NULL) {
logit(LOG_ERR, "%s: can't allocate memory",
__func__);
goto bad;
}
pfxlist->opt = hdr;
TAILQ_INSERT_TAIL(&ndopts->nd_opts_list, pfxlist, next);

break;
}
default: /* impossible */
break;
}
}

return 0;

bad:
free_ndopts(ndopts);
return -1;
}

static void
free_ndopts(union nd_opts *ndopts)
{
struct nd_optlist *opt;

while ((opt = TAILQ_FIRST(&ndopts->nd_opts_list)) != NULL) {
TAILQ_REMOVE(&ndopts->nd_opts_list, opt, next);
free(opt);
}
}

void
sock_open(void)
{
struct icmp6_filter filt;
struct ipv6_mreq mreq;
struct rainfo *ra;
int on;
/* XXX: should be max MTU attached to the node */
static unsigned char answer[1500];

rcvcmsgbuflen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
CMSG_SPACE(sizeof(int));
rcvcmsgbuf = malloc(rcvcmsgbuflen);
if (rcvcmsgbuf == NULL) {
logit(LOG_ERR, "%s: malloc: %m", __func__);
exit(EXIT_FAILURE);
}

sndcmsgbuflen = CMSG_SPACE(sizeof(struct in6_pktinfo));
sndcmsgbuf = malloc(sndcmsgbuflen);
if (sndcmsgbuf == NULL) {
logit(LOG_ERR, "%s: malloc: %m", __func__);
exit(EXIT_FAILURE);
}

if ((sock = prog_socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) == -1) {
logit(LOG_ERR, "%s: socket: %m", __func__);
exit(EXIT_FAILURE);
}

/* RFC 4861 Section 4.2 */
on = 255;
if (prog_setsockopt(sock, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &on,
sizeof(on)) == -1) {
logit(LOG_ERR, "%s: IPV6_MULTICAST_HOPS: %m", __func__);
exit(EXIT_FAILURE);
}
on = 255;
if (prog_setsockopt(sock, IPPROTO_IPV6, IPV6_UNICAST_HOPS, &on,
sizeof(on)) == -1) {
logit(LOG_ERR, "%s: IPV6_UNICAST_HOPS: %m", __func__);
exit(EXIT_FAILURE);
}

/* specify to tell receiving interface */
on = 1;
if (prog_setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
sizeof(on)) == -1) {
logit(LOG_ERR, "%s: IPV6_RECVPKTINFO: %m", __func__);
exit(EXIT_FAILURE);
}

on = 1;
/* specify to tell value of hoplimit field of received IP6 hdr */
if (prog_setsockopt(sock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
sizeof(on)) == -1) {
logit(LOG_ERR, "%s: IPV6_RECVHOPLIMIT: %m", __func__);
exit(EXIT_FAILURE);
}

ICMP6_FILTER_SETBLOCKALL(&filt);
ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
if (prog_setsockopt(sock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
sizeof(filt)) == -1) {
logit(LOG_ERR, "%s: IICMP6_FILTER: %m", __func__);
exit(EXIT_FAILURE);
}

/*
* join all routers multicast address on each advertising interface.
*/
if (inet_pton(AF_INET6, ALLROUTERS_LINK,
mreq.ipv6mr_multiaddr.s6_addr) != 1)
{
logit(LOG_ERR, "%s: inet_pton failed(library bug?)",
__func__);
exit(EXIT_FAILURE);
}
TAILQ_FOREACH(ra, &ralist, next) {
mreq.ipv6mr_interface = ra->ifindex;
if (prog_setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, &mreq,
sizeof(mreq)) == -1) {
logit(LOG_ERR, "%s: IPV6_JOIN_GROUP(link) on %s: %m",
__func__, ra->ifname);
continue;
}
}

/* initialize msghdr for receiving packets */
rcviov[0].iov_base = answer;
rcviov[0].iov_len = sizeof(answer);
rcvmhdr.msg_name = &rcvfrom;
rcvmhdr.msg_namelen = sizeof(rcvfrom);
rcvmhdr.msg_iov = rcviov;
rcvmhdr.msg_iovlen = 1;
rcvmhdr.msg_control = rcvcmsgbuf;
rcvmhdr.msg_controllen = rcvcmsgbuflen;

/* initialize msghdr for sending packets */
sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
sndmhdr.msg_iov = sndiov;
sndmhdr.msg_iovlen = 1;
sndmhdr.msg_control = sndcmsgbuf;
sndmhdr.msg_controllen = sndcmsgbuflen;
}

/* open a routing socket to watch the routing table */
static void
rtsock_open(void)
{
#ifdef RO_MSGFILTER
unsigned char msgfilter[] = {
RTM_ADD, RTM_DELETE,
RTM_NEWADDR, RTM_DELADDR,
#ifdef RTM_IFANNOUNCE
RTM_IFANNOUNCE,
#endif
RTM_IFINFO,
};
#endif

if ((rtsock = prog_socket(PF_ROUTE, SOCK_RAW, 0)) == -1) {
logit(LOG_ERR, "%s: socket: %m", __func__);
exit(EXIT_FAILURE);
}
#ifdef RO_MSGFILTER
if (prog_setsockopt(rtsock, PF_ROUTE, RO_MSGFILTER,
&msgfilter, sizeof(msgfilter)) == -1)
logit(LOG_ERR, "%s: RO_MSGFILTER: %m", __func__);
#endif
}

struct rainfo *
if_indextorainfo(unsigned int idx)
{
struct rainfo *rai;

TAILQ_FOREACH(rai, &ralist, next) {
if (rai->ifindex == idx)
return rai;
}

return NULL; /* search failed */
}

struct rainfo *
ra_output(struct rainfo *rai, bool solicited)
{
int i;
struct cmsghdr *cm;
struct in6_pktinfo *pi;
struct soliciter *sol;

if ((rai->ifflags & IFF_UP) == 0) {
logit(LOG_DEBUG, "%s: %s is not up, skip sending RA",
__func__, rai->ifname);
return NULL;
}

make_packet(rai); /* XXX: inefficient */

sndmhdr.msg_name = (void *)&sin6_linklocal_allnodes;
sndmhdr.msg_iov[0].iov_base = (void *)rai->ra_data;
sndmhdr.msg_iov[0].iov_len = rai->ra_datalen;

/* specify the outgoing interface */
cm = CMSG_FIRSTHDR(&sndmhdr);
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 = rai->ifindex;

logit(LOG_DEBUG,
"%s: send RA on %s, # of waitings = %d",
__func__, rai->ifname, rai->waiting);

if (solicited) {
/* unicast solicited RA's as per RFC 7772 */
while ((sol = TAILQ_FIRST(&rai->soliciter)) != NULL) {
sndmhdr.msg_name = (void *)&sol->addr;
i = prog_sendmsg(sock, &sndmhdr, 0);
if (i < 0 || (size_t)i != rai->ra_datalen) {
if (i < 0) {
logit(LOG_ERR,
"%s: unicast sendmsg on %s: %m",
__func__, rai->ifname);
}
}
TAILQ_REMOVE(&rai->soliciter, sol, next);
free(sol);
}

/* reset waiting counter */
rai->waiting = 0;

/* disable timer */
rai->timer_sol->enabled = false;

return rai;
}

i = prog_sendmsg(sock, &sndmhdr, 0);
if (i < 0 || (size_t)i != rai->ra_datalen) {
if (i < 0) {
logit(LOG_ERR, "%s: sendmsg on %s: %m",
__func__, rai->ifname);
}
}

if (rai->leaving_adv > 0) {
if (--(rai->leaving_adv) == 0) {
/* leaving for ourself means we're shutting down */
if (rai->leaving_for == rai) {
TAILQ_REMOVE(&ralist, rai, next);
free_rainfo(rai);
return NULL;
}
logit(LOG_DEBUG,
"%s: expired RA,"
" new config active for interface (%s)",
__func__, rai->ifname);
ra_timer_reset(rai->leaving_for);
rai->leaving_for->leaving = NULL;
free_rainfo(rai);
return NULL;
}
}

/* update counter */
if (rai->initcounter < MAX_INITIAL_RTR_ADVERTISEMENTS)
rai->initcounter++;
rai->raoutput++;

/* update timestamp */
prog_clock_gettime(CLOCK_MONOTONIC, &rai->lastsent);
return rai;
}

/* process unsolicited RA timer */
struct rtadvd_timer *
ra_timeout(void *data)
{
struct rainfo *rai = (struct rainfo *)data;

logit(LOG_DEBUG,
"%s: unsolicited RA timer on %s is expired",
__func__, rai->ifname);

if (ra_output(rai, false))
return rai->timer;
return NULL;
}

/* process solicited RA timer */
struct rtadvd_timer *
ra_timeout_sol(void *data)
{
struct rainfo *rai = (struct rainfo *)data;

logit(LOG_DEBUG,
"%s: solicited RA timer on %s is expired",
__func__, rai->ifname);

if (ra_output(rai, true))
return rai->timer_sol;
return NULL;
}

/* update RA timer */
void
ra_timer_update(void *data, struct timespec *tm)
{
struct rainfo *rai = (struct rainfo *)data;
long interval;

/*
* Whenever a multicast advertisement is sent from an interface,
* the timer is reset to a uniformly-distributed random value
* between the interface's configured MinRtrAdvInterval and
* MaxRtrAdvInterval (RFC2461 6.2.4).
*/
interval = rai->mininterval;
if (rai->mininterval != rai->maxinterval)
interval += arc4random() % (rai->maxinterval-rai->mininterval);

/*
* For the first few advertisements (up to
* MAX_INITIAL_RTR_ADVERTISEMENTS), if the randomly chosen interval
* is greater than MAX_INITIAL_RTR_ADVERT_INTERVAL, the timer
* SHOULD be set to MAX_INITIAL_RTR_ADVERT_INTERVAL instead.
* (RFC-2461 6.2.4)
*/
if (rai->initcounter < MAX_INITIAL_RTR_ADVERTISEMENTS &&
interval > MAX_INITIAL_RTR_ADVERT_INTERVAL)
interval = MAX_INITIAL_RTR_ADVERT_INTERVAL;

tm->tv_sec = interval;
tm->tv_nsec = 0;

logit(LOG_DEBUG,
"%s: RA timer on %s is set to %jd:%jd",
__func__, rai->ifname,
(intmax_t)tm->tv_sec, (intmax_t)tm->tv_nsec);
}

void
logit(int level, const char *fmt, ...)
{
va_list ap;
char *buf;

va_start(ap, fmt);
if (!Dflag && after_daemon) {
vsyslog(level, fmt, ap);
goto out;
}
if (level >= LOG_INFO && !dflag) {
goto out;
}

vwarnx(expandm(fmt, "", &buf), ap);
free(buf);
out:
va_end(ap);
}