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freebsd-skq/usr.sbin/rtadvd/rtadvd.c
bz 3431d451a5 Initial implementation of draft-ietf-6man-ipv6only-flag. 
This change defines the RA "6" (IPv6-Only) flag which routers
may advertise, kernel logic to check if all routers on a link
have the flag set and accordingly update a per-interface flag.

If all routers agree that it is an IPv6-only link, ether_output_frame(),
based on the interface flag, will filter out all ETHERTYPE_IP/ARP
frames, drop them, and return EAFNOSUPPORT to upper layers.

The change also updates ndp to show the "6" flag, ifconfig to
display the IPV6_ONLY nd6 flag if set, and rtadvd to allow
announcing the flag.

Further changes to tcpdump (contrib code) are availble and will
be upstreamed.

Tested the code (slightly earlier version) with 2 FreeBSD
IPv6 routers, a FreeBSD laptop on ethernet as well as wifi,
and with Win10 and OSX clients (which did not fall over with
the "6" flag set but not understood).

We may also want to (a) implement and RX filter, and (b) over
time enahnce user space to, say, stop dhclient from running
when the interface flag is set.  Also we might want to start
IPv6 before IPv4 in the future.

All the code is hidden under the EXPERIMENTAL option and not
compiled by default as the draft is a work-in-progress and
we cannot rely on the fact that IANA will assign the bits
as requested by the draft and hence they may change.

Dear 6man, you have running code.

Discussed with:	Bob Hinden, Brian E Carpenter
2018-10-30 20:08:48 +00:00

1930 lines
50 KiB
C
Raw Blame History

/* $FreeBSD$ */
/* $KAME: rtadvd.c,v 1.82 2003/08/05 12:34:23 itojun Exp $ */
/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* Copyright (C) 2011 Hiroki Sato <hrs@FreeBSD.org>
* 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/ioctl.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/queue.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_media.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <arpa/inet.h>
#include <netinet/in_var.h>
#include <netinet6/nd6.h>
#include <time.h>
#include <unistd.h>
#include <stdio.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <libutil.h>
#include <netdb.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <syslog.h>
#include <poll.h>
#include "pathnames.h"
#include "rtadvd.h"
#include "if.h"
#include "rrenum.h"
#include "advcap.h"
#include "timer_subr.h"
#include "timer.h"
#include "config.h"
#include "control.h"
#include "control_server.h"
#define RTADV_TYPE2BITMASK(type) (0x1 << type)
struct msghdr rcvmhdr;
static char *rcvcmsgbuf;
static size_t rcvcmsgbuflen;
static char *sndcmsgbuf = NULL;
static size_t sndcmsgbuflen;
struct msghdr sndmhdr;
struct iovec rcviov[2];
struct iovec sndiov[2];
struct sockaddr_in6 rcvfrom;
static const char *pidfilename = _PATH_RTADVDPID;
const char *conffile = _PATH_RTADVDCONF;
static struct pidfh *pfh;
static int dflag, sflag;
static int wait_shutdown;
#define PFD_RAWSOCK 0
#define PFD_RTSOCK 1
#define PFD_CSOCK 2
#define PFD_MAX 3
struct railist_head_t railist =
TAILQ_HEAD_INITIALIZER(railist);
struct ifilist_head_t ifilist =
TAILQ_HEAD_INITIALIZER(ifilist);
struct nd_optlist {
TAILQ_ENTRY(nd_optlist) nol_next;
struct nd_opt_hdr *nol_opt;
};
union nd_opt {
struct nd_opt_hdr *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) opt_list;
} nd_opt_each;
};
#define opt_src_lladdr nd_opt_each.src_lladdr
#define opt_tgt_lladdr nd_opt_each.tgt_lladdr
#define opt_pi nd_opt_each.pi
#define opt_rh nd_opt_each.rh
#define opt_mtu nd_opt_each.mtu
#define opt_list nd_opt_each.opt_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)
static 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,
};
static void rtadvd_shutdown(void);
static void sock_open(struct sockinfo *);
static void rtsock_open(struct sockinfo *);
static void rtadvd_input(struct sockinfo *);
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 int prefix_check(struct nd_opt_prefix_info *, struct rainfo *,
struct sockaddr_in6 *);
static int nd6_options(struct nd_opt_hdr *, int,
union nd_opt *, uint32_t);
static void free_ndopts(union nd_opt *);
static void rtmsg_input(struct sockinfo *);
static void set_short_delay(struct ifinfo *);
static int check_accept_rtadv(int);
static void
usage(void)
{
fprintf(stderr, "usage: rtadvd [-dDfRs] "
"[-c configfile] [-C ctlsock] [-M ifname] [-p pidfile]\n");
exit(1);
}
int
main(int argc, char *argv[])
{
struct pollfd set[PFD_MAX];
struct timespec *timeout;
int i, ch;
int fflag = 0, logopt;
int error;
pid_t pid, otherpid;
/* get command line options and arguments */
while ((ch = getopt(argc, argv, "c:C:dDfhM:p:Rs")) != -1) {
switch (ch) {
case 'c':
conffile = optarg;
break;
case 'C':
ctrlsock.si_name = optarg;
break;
case 'd':
dflag++;
break;
case 'D':
dflag += 3;
break;
case 'f':
fflag = 1;
break;
case 'M':
mcastif = optarg;
break;
case 'R':
fprintf(stderr, "rtadvd: "
"the -R option is currently ignored.\n");
/* accept_rr = 1; */
/* run anyway... */
break;
case 's':
sflag = 1;
break;
case 'p':
pidfilename = optarg;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
logopt = LOG_NDELAY | LOG_PID;
if (fflag)
logopt |= LOG_PERROR;
openlog("rtadvd", logopt, LOG_DAEMON);
/* set log level */
if (dflag > 2)
(void)setlogmask(LOG_UPTO(LOG_DEBUG));
else if (dflag > 1)
(void)setlogmask(LOG_UPTO(LOG_INFO));
else if (dflag > 0)
(void)setlogmask(LOG_UPTO(LOG_NOTICE));
else
(void)setlogmask(LOG_UPTO(LOG_ERR));
/* timer initialization */
rtadvd_timer_init();
pfh = pidfile_open(pidfilename, 0600, &otherpid);
if (pfh == NULL) {
if (errno == EEXIST)
errx(1, "%s already running, pid: %d",
getprogname(), otherpid);
syslog(LOG_ERR,
"failed to open the pid file %s, run anyway.",
pidfilename);
}
if (!fflag)
daemon(1, 0);
sock_open(&sock);
update_ifinfo(&ifilist, UPDATE_IFINFO_ALL);
for (i = 0; i < argc; i++)
update_persist_ifinfo(&ifilist, argv[i]);
csock_open(&ctrlsock, S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);
if (ctrlsock.si_fd == -1) {
syslog(LOG_ERR, "cannot open control socket: %s",
strerror(errno));
exit(1);
}
/* record the current PID */
pid = getpid();
pidfile_write(pfh);
set[PFD_RAWSOCK].fd = sock.si_fd;
set[PFD_RAWSOCK].events = POLLIN;
if (sflag == 0) {
rtsock_open(&rtsock);
set[PFD_RTSOCK].fd = rtsock.si_fd;
set[PFD_RTSOCK].events = POLLIN;
} else
set[PFD_RTSOCK].fd = -1;
set[PFD_CSOCK].fd = ctrlsock.si_fd;
set[PFD_CSOCK].events = POLLIN;
signal(SIGTERM, set_do_shutdown);
signal(SIGINT, set_do_shutdown);
signal(SIGHUP, set_do_reload);
error = csock_listen(&ctrlsock);
if (error) {
syslog(LOG_ERR, "cannot listen control socket: %s",
strerror(errno));
exit(1);
}
/* load configuration file */
set_do_reload(0);
while (1) {
if (is_do_shutdown())
rtadvd_shutdown();
if (is_do_reload()) {
loadconfig_ifname(reload_ifname());
if (reload_ifname() == NULL)
syslog(LOG_INFO,
"configuration file reloaded.");
else
syslog(LOG_INFO,
"configuration file for %s reloaded.",
reload_ifname());
reset_do_reload();
}
/* timeout handler update for active interfaces */
rtadvd_update_timeout_handler();
/* timer expiration check and reset the timer */
timeout = rtadvd_check_timer();
if (timeout != NULL) {
syslog(LOG_DEBUG,
"<%s> set timer to %ld:%ld. waiting for "
"inputs or timeout", __func__,
(long int)timeout->tv_sec,
(long int)timeout->tv_nsec / 1000);
} else {
syslog(LOG_DEBUG,
"<%s> there's no timer. waiting for inputs",
__func__);
}
if ((i = poll(set, sizeof(set)/sizeof(set[0]),
timeout ? (timeout->tv_sec * 1000 +
timeout->tv_nsec / 1000 / 1000) : INFTIM)) < 0) {
/* EINTR would occur if a signal was delivered */
if (errno != EINTR)
syslog(LOG_ERR, "poll() failed: %s",
strerror(errno));
continue;
}
if (i == 0) /* timeout */
continue;
if (rtsock.si_fd != -1 && set[PFD_RTSOCK].revents & POLLIN)
rtmsg_input(&rtsock);
if (set[PFD_RAWSOCK].revents & POLLIN)
rtadvd_input(&sock);
if (set[PFD_CSOCK].revents & POLLIN) {
int fd;
fd = csock_accept(&ctrlsock);
if (fd == -1)
syslog(LOG_ERR,
"cannot accept() control socket: %s",
strerror(errno));
else {
cm_handler_server(fd);
close(fd);
}
}
}
exit(0); /* NOTREACHED */
}
static void
rtadvd_shutdown(void)
{
struct ifinfo *ifi;
struct rainfo *rai;
struct rdnss *rdn;
struct dnssl *dns;
if (wait_shutdown) {
syslog(LOG_INFO,
"waiting expiration of the all RA timers.");
TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
/*
* Ignore !IFF_UP interfaces in waiting for shutdown.
*/
if (!(ifi->ifi_flags & IFF_UP) &&
ifi->ifi_ra_timer != NULL) {
ifi->ifi_state = IFI_STATE_UNCONFIGURED;
rtadvd_remove_timer(ifi->ifi_ra_timer);
ifi->ifi_ra_timer = NULL;
syslog(LOG_DEBUG, "<%s> %s(idx=%d) is down. "
"Timer removed and marked as UNCONFIGURED.",
__func__, ifi->ifi_ifname,
ifi->ifi_ifindex);
}
}
TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
if (ifi->ifi_ra_timer != NULL)
break;
}
if (ifi == NULL) {
syslog(LOG_NOTICE, "gracefully terminated.");
exit(0);
}
sleep(1);
return;
}
syslog(LOG_DEBUG, "<%s> cease to be an advertising router",
__func__);
wait_shutdown = 1;
TAILQ_FOREACH(rai, &railist, rai_next) {
rai->rai_lifetime = 0;
TAILQ_FOREACH(rdn, &rai->rai_rdnss, rd_next)
rdn->rd_ltime = 0;
TAILQ_FOREACH(dns, &rai->rai_dnssl, dn_next)
dns->dn_ltime = 0;
}
TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
if (!ifi->ifi_persist)
continue;
if (ifi->ifi_state == IFI_STATE_UNCONFIGURED)
continue;
if (ifi->ifi_ra_timer == NULL)
continue;
if (ifi->ifi_ra_lastsent.tv_sec == 0 &&
ifi->ifi_ra_lastsent.tv_nsec == 0 &&
ifi->ifi_ra_timer != NULL) {
/*
* When RA configured but never sent,
* ignore the IF immediately.
*/
rtadvd_remove_timer(ifi->ifi_ra_timer);
ifi->ifi_ra_timer = NULL;
ifi->ifi_state = IFI_STATE_UNCONFIGURED;
continue;
}
ifi->ifi_state = IFI_STATE_TRANSITIVE;
/* Mark as the shut-down state. */
ifi->ifi_rainfo_trans = ifi->ifi_rainfo;
ifi->ifi_rainfo = NULL;
ifi->ifi_burstcount = MAX_FINAL_RTR_ADVERTISEMENTS;
ifi->ifi_burstinterval = MIN_DELAY_BETWEEN_RAS;
ra_timer_update(ifi, &ifi->ifi_ra_timer->rat_tm);
rtadvd_set_timer(&ifi->ifi_ra_timer->rat_tm,
ifi->ifi_ra_timer);
}
syslog(LOG_NOTICE, "final RA transmission started.");
pidfile_remove(pfh);
csock_close(&ctrlsock);
}
static void
rtmsg_input(struct sockinfo *s)
{
int n, type, ifindex = 0, plen;
size_t len;
char msg[2048], *next, *lim;
char ifname[IFNAMSIZ];
struct if_announcemsghdr *ifan;
struct rt_msghdr *rtm;
struct prefix *pfx;
struct rainfo *rai;
struct in6_addr *addr;
struct ifinfo *ifi;
char addrbuf[INET6_ADDRSTRLEN];
int prefixchange = 0;
if (s == NULL) {
syslog(LOG_ERR, "<%s> internal error", __func__);
exit(1);
}
n = read(s->si_fd, msg, sizeof(msg));
rtm = (struct rt_msghdr *)msg;
syslog(LOG_DEBUG, "<%s> received a routing message "
"(type = %d, len = %d)", __func__, rtm->rtm_type, n);
if (n > rtm->rtm_msglen) {
/*
* This usually won't happen for messages received on
* a routing socket.
*/
syslog(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, rtm->rtm_msglen);
#if 0
/* adjust length */
n = rtm->rtm_msglen;
#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) |
RTADV_TYPE2BITMASK(RTM_IFINFO) |
RTADV_TYPE2BITMASK(RTM_IFANNOUNCE));
if (len == 0)
break;
type = ((struct rt_msghdr *)next)->rtm_type;
switch (type) {
case RTM_ADD:
case RTM_DELETE:
ifindex = get_rtm_ifindex(next);
break;
case RTM_NEWADDR:
case RTM_DELADDR:
ifindex = (int)((struct ifa_msghdr *)next)->ifam_index;
break;
case RTM_IFINFO:
ifindex = (int)((struct if_msghdr *)next)->ifm_index;
break;
case RTM_IFANNOUNCE:
ifan = (struct if_announcemsghdr *)next;
switch (ifan->ifan_what) {
case IFAN_ARRIVAL:
case IFAN_DEPARTURE:
break;
default:
syslog(LOG_DEBUG,
"<%s:%d> unknown ifan msg (ifan_what=%d)",
__func__, __LINE__, ifan->ifan_what);
continue;
}
syslog(LOG_DEBUG, "<%s>: if_announcemsg (idx=%d:%d)",
__func__, ifan->ifan_index, ifan->ifan_what);
switch (ifan->ifan_what) {
case IFAN_ARRIVAL:
syslog(LOG_NOTICE,
"interface added (idx=%d)",
ifan->ifan_index);
update_ifinfo(&ifilist, ifan->ifan_index);
loadconfig_index(ifan->ifan_index);
break;
case IFAN_DEPARTURE:
syslog(LOG_NOTICE,
"interface removed (idx=%d)",
ifan->ifan_index);
rm_ifinfo_index(ifan->ifan_index);
/* Clear ifi_ifindex */
TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
if (ifi->ifi_ifindex
== ifan->ifan_index) {
ifi->ifi_ifindex = 0;
break;
}
}
update_ifinfo(&ifilist, ifan->ifan_index);
break;
}
continue;
default:
/* should not reach here */
syslog(LOG_DEBUG,
"<%s:%d> unknown rtmsg %d on %s",
__func__, __LINE__, type,
if_indextoname(ifindex, ifname));
continue;
}
ifi = if_indextoifinfo(ifindex);
if (ifi == NULL) {
syslog(LOG_DEBUG,
"<%s> ifinfo not found for idx=%d. Why?",
__func__, ifindex);
continue;
}
rai = ifi->ifi_rainfo;
if (rai == NULL) {
syslog(LOG_DEBUG,
"<%s> route changed on "
"non advertising interface(%s)",
__func__, ifi->ifi_ifname);
continue;
}
oldifflags = ifi->ifi_flags;
/* init ifflags because it may have changed */
update_ifinfo(&ifilist, ifindex);
switch (type) {
case RTM_ADD:
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) {
syslog(LOG_INFO, "<%s> new interface route's"
"plen %d is invalid for a prefix",
__func__, plen);
break;
}
pfx = find_prefix(rai, addr, plen);
if (pfx) {
if (pfx->pfx_timer) {
/*
* If the prefix has been invalidated,
* make it available again.
*/
update_prefix(pfx);
prefixchange = 1;
} else
syslog(LOG_DEBUG,
"<%s> new prefix(%s/%d) "
"added on %s, "
"but it was already in list",
__func__,
inet_ntop(AF_INET6, addr,
(char *)addrbuf,
sizeof(addrbuf)),
plen, ifi->ifi_ifname);
break;
}
make_prefix(rai, ifindex, addr, plen);
prefixchange = 1;
break;
case RTM_DELETE:
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) {
syslog(LOG_INFO,
"<%s> deleted interface route's "
"plen %d is invalid for a prefix",
__func__, plen);
break;
}
pfx = find_prefix(rai, addr, plen);
if (pfx == NULL) {
syslog(LOG_DEBUG,
"<%s> prefix(%s/%d) was deleted on %s, "
"but it was not in list",
__func__, inet_ntop(AF_INET6, addr,
(char *)addrbuf, sizeof(addrbuf)),
plen, ifi->ifi_ifname);
break;
}
invalidate_prefix(pfx);
prefixchange = 1;
break;
case RTM_NEWADDR:
case RTM_DELADDR:
case RTM_IFINFO:
break;
default:
/* should not reach here */
syslog(LOG_DEBUG,
"<%s:%d> unknown rtmsg %d on %s",
__func__, __LINE__, type,
if_indextoname(ifindex, ifname));
return;
}
/* check if an interface flag is changed */
if ((oldifflags & IFF_UP) && /* UP to DOWN */
!(ifi->ifi_flags & IFF_UP)) {
syslog(LOG_NOTICE,
"<interface %s becomes down. stop timer.",
ifi->ifi_ifname);
rtadvd_remove_timer(ifi->ifi_ra_timer);
ifi->ifi_ra_timer = NULL;
} else if (!(oldifflags & IFF_UP) && /* DOWN to UP */
(ifi->ifi_flags & IFF_UP)) {
syslog(LOG_NOTICE,
"interface %s becomes up. restart timer.",
ifi->ifi_ifname);
ifi->ifi_state = IFI_STATE_TRANSITIVE;
ifi->ifi_burstcount =
MAX_INITIAL_RTR_ADVERTISEMENTS;
ifi->ifi_burstinterval =
MAX_INITIAL_RTR_ADVERT_INTERVAL;
ifi->ifi_ra_timer = rtadvd_add_timer(ra_timeout,
ra_timer_update, ifi, ifi);
ra_timer_update(ifi, &ifi->ifi_ra_timer->rat_tm);
rtadvd_set_timer(&ifi->ifi_ra_timer->rat_tm,
ifi->ifi_ra_timer);
} else if (prefixchange &&
(ifi->ifi_flags & IFF_UP)) {
/*
* An advertised prefix has been added or invalidated.
* Will notice the change in a short delay.
*/
set_short_delay(ifi);
}
}
return;
}
void
rtadvd_input(struct sockinfo *s)
{
ssize_t i;
int *hlimp = NULL;
#ifdef OLDRAWSOCKET
struct ip6_hdr *ip;
#endif
struct icmp6_hdr *icp;
int ifindex = 0;
struct cmsghdr *cm;
struct in6_pktinfo *pi = NULL;
char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
struct in6_addr dst = in6addr_any;
struct ifinfo *ifi;
syslog(LOG_DEBUG, "<%s> enter", __func__);
if (s == NULL) {
syslog(LOG_ERR, "<%s> internal error", __func__);
exit(1);
}
/*
* 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 = recvmsg(s->si_fd, &rcvmhdr, 0)) < 0)
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;
dst = pi->ipi6_addr;
}
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) {
syslog(LOG_ERR, "failed to get receiving interface");
return;
}
if (hlimp == NULL) {
syslog(LOG_ERR, "failed to get receiving hop limit");
return;
}
/*
* If we happen to receive data on an interface which is now gone
* or down, just discard the data.
*/
ifi = if_indextoifinfo(pi->ipi6_ifindex);
if (ifi == NULL || !(ifi->ifi_flags & IFF_UP)) {
syslog(LOG_INFO,
"<%s> received data on a disabled interface (%s)",
__func__,
(ifi == NULL) ? "[gone]" : ifi->ifi_ifname);
return;
}
#ifdef OLDRAWSOCKET
if ((size_t)i < sizeof(struct ip6_hdr) + sizeof(struct icmp6_hdr)) {
syslog(LOG_ERR,
"packet size(%d) is too short", i);
return;
}
ip = (struct ip6_hdr *)rcvmhdr.msg_iov[0].iov_base;
icp = (struct icmp6_hdr *)(ip + 1); /* XXX: ext. hdr? */
#else
if ((size_t)i < sizeof(struct icmp6_hdr)) {
syslog(LOG_ERR, "packet size(%zd) is too short", i);
return;
}
icp = (struct icmp6_hdr *)rcvmhdr.msg_iov[0].iov_base;
#endif
switch (icp->icmp6_type) {
case ND_ROUTER_SOLICIT:
/*
* Message verification - RFC 4861 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) {
syslog(LOG_NOTICE,
"RS with invalid hop limit(%d) "
"received from %s on %s",
*hlimp,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if (icp->icmp6_code) {
syslog(LOG_NOTICE,
"RS with invalid ICMP6 code(%d) "
"received from %s on %s",
icp->icmp6_code,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if ((size_t)i < sizeof(struct nd_router_solicit)) {
syslog(LOG_NOTICE,
"RS from %s on %s does not have enough "
"length (len = %zd)",
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
sizeof(ntopbuf)),
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 4861 6.1.2
* XXX: there's the same dilemma as above...
*/
if (!IN6_IS_ADDR_LINKLOCAL(&rcvfrom.sin6_addr)) {
syslog(LOG_NOTICE,
"RA with non-linklocal source address "
"received from %s on %s",
inet_ntop(AF_INET6, &rcvfrom.sin6_addr,
ntopbuf, sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if (*hlimp != 255) {
syslog(LOG_NOTICE,
"RA with invalid hop limit(%d) "
"received from %s on %s",
*hlimp,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if (icp->icmp6_code) {
syslog(LOG_NOTICE,
"RA with invalid ICMP6 code(%d) "
"received from %s on %s",
icp->icmp6_code,
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
return;
}
if ((size_t)i < sizeof(struct nd_router_advert)) {
syslog(LOG_NOTICE,
"RA from %s on %s does not have enough "
"length (len = %zd)",
inet_ntop(AF_INET6, &rcvfrom.sin6_addr, ntopbuf,
sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf), i);
return;
}
ra_input(i, (struct nd_router_advert *)icp, pi, &rcvfrom);
break;
case ICMP6_ROUTER_RENUMBERING:
if (mcastif == NULL) {
syslog(LOG_ERR, "received a router renumbering "
"message, but not allowed to be accepted");
break;
}
rr_input(i, (struct icmp6_router_renum *)icp, pi, &rcvfrom,
&dst);
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()).
*/
syslog(LOG_ERR, "invalid icmp type(%d)", icp->icmp6_type);
return;
}
return;
}
static void
rs_input(int len, struct nd_router_solicit *rs,
struct in6_pktinfo *pi, struct sockaddr_in6 *from)
{
char ntopbuf[INET6_ADDRSTRLEN];
char ifnamebuf[IFNAMSIZ];
union nd_opt ndopts;
struct rainfo *rai;
struct ifinfo *ifi;
struct soliciter *sol;
syslog(LOG_DEBUG,
"<%s> RS received from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf, sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
/* ND option check */
memset(&ndopts, 0, sizeof(ndopts));
TAILQ_INIT(&ndopts.opt_list);
if (nd6_options((struct nd_opt_hdr *)(rs + 1),
len - sizeof(struct nd_router_solicit),
&ndopts, NDOPT_FLAG_SRCLINKADDR)) {
syslog(LOG_INFO,
"<%s> ND option check failed for an RS from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)),
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 4861 6.1.1)
*/
if (IN6_IS_ADDR_UNSPECIFIED(&from->sin6_addr) &&
ndopts.opt_src_lladdr) {
syslog(LOG_INFO,
"<%s> RS from unspecified src on %s has a link-layer"
" address option",
__func__, if_indextoname(pi->ipi6_ifindex, ifnamebuf));
goto done;
}
ifi = if_indextoifinfo(pi->ipi6_ifindex);
if (ifi == NULL) {
syslog(LOG_INFO,
"<%s> if (idx=%d) not found. Why?",
__func__, pi->ipi6_ifindex);
goto done;
}
rai = ifi->ifi_rainfo;
if (rai == NULL) {
syslog(LOG_INFO,
"<%s> RS received on non advertising interface(%s)",
__func__,
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
goto done;
}
rai->rai_ifinfo->ifi_rsinput++;
/*
* Decide whether to send RA according to the rate-limit
* consideration.
*/
/* record sockaddr waiting for RA, if possible */
sol = (struct soliciter *)malloc(sizeof(*sol));
if (sol) {
sol->sol_addr = *from;
/* XXX RFC 2553 need clarification on flowinfo */
sol->sol_addr.sin6_flowinfo = 0;
TAILQ_INSERT_TAIL(&rai->rai_soliciter, sol, sol_next);
}
/*
* If there is already a waiting RS packet, don't
* update the timer.
*/
if (ifi->ifi_rs_waitcount++)
goto done;
set_short_delay(ifi);
done:
free_ndopts(&ndopts);
return;
}
static void
set_short_delay(struct ifinfo *ifi)
{
long delay; /* must not be greater than 1000000 */
struct timespec interval, now, min_delay, tm_tmp, *rest;
if (ifi->ifi_ra_timer == NULL)
return;
/*
* 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. RFC 4861 6.2.6
*/
delay = arc4random_uniform(MAX_RA_DELAY_TIME);
interval.tv_sec = 0;
interval.tv_nsec = delay * 1000;
rest = rtadvd_timer_rest(ifi->ifi_ra_timer);
if (TS_CMP(rest, &interval, <)) {
syslog(LOG_DEBUG, "<%s> random delay is larger than "
"the rest of the 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.
*/
clock_gettime(CLOCK_MONOTONIC_FAST, &now);
TS_SUB(&now, &ifi->ifi_ra_lastsent, &tm_tmp);
min_delay.tv_sec = MIN_DELAY_BETWEEN_RAS;
min_delay.tv_nsec = 0;
if (TS_CMP(&tm_tmp, &min_delay, <)) {
TS_SUB(&min_delay, &tm_tmp, &min_delay);
TS_ADD(&min_delay, &interval, &interval);
}
rtadvd_set_timer(&interval, ifi->ifi_ra_timer);
}
static int
check_accept_rtadv(int idx)
{
struct ifinfo *ifi;
TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
if (ifi->ifi_ifindex == idx)
break;
}
if (ifi == NULL) {
syslog(LOG_DEBUG,
"<%s> if (idx=%d) not found. Why?",
__func__, idx);
return (0);
}
#if (__FreeBSD_version < 900000)
/*
* RA_RECV: !ip6.forwarding && ip6.accept_rtadv
* RA_SEND: ip6.forwarding
*/
return ((getinet6sysctl(IPV6CTL_FORWARDING) == 0) &&
(getinet6sysctl(IPV6CTL_ACCEPT_RTADV) == 1));
#else
/*
* RA_RECV: ND6_IFF_ACCEPT_RTADV
* RA_SEND: ip6.forwarding
*/
if (update_ifinfo_nd_flags(ifi) != 0) {
syslog(LOG_ERR, "cannot get nd6 flags (idx=%d)", idx);
return (0);
}
return (ifi->ifi_nd_flags & ND6_IFF_ACCEPT_RTADV);
#endif
}
static void
ra_input(int len, struct nd_router_advert *nra,
struct in6_pktinfo *pi, struct sockaddr_in6 *from)
{
struct rainfo *rai;
struct ifinfo *ifi;
char ntopbuf[INET6_ADDRSTRLEN];
char ifnamebuf[IFNAMSIZ];
union nd_opt ndopts;
const char *on_off[] = {"OFF", "ON"};
uint32_t reachabletime, retranstimer, mtu;
int inconsistent = 0;
int error;
syslog(LOG_DEBUG, "<%s> RA received from %s on %s", __func__,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf, sizeof(ntopbuf)),
if_indextoname(pi->ipi6_ifindex, ifnamebuf));
/* ND option check */
memset(&ndopts, 0, sizeof(ndopts));
TAILQ_INIT(&ndopts.opt_list);
error = nd6_options((struct nd_opt_hdr *)(nra + 1),
len - sizeof(struct nd_router_advert), &ndopts,
NDOPT_FLAG_SRCLINKADDR | NDOPT_FLAG_PREFIXINFO | NDOPT_FLAG_MTU |
NDOPT_FLAG_RDNSS | NDOPT_FLAG_DNSSL);
if (error) {
syslog(LOG_INFO,
"<%s> ND option check failed for an RA from %s on %s",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), if_indextoname(pi->ipi6_ifindex,
ifnamebuf));
return;
}
/*
* RA consistency check according to RFC 4861 6.2.7
*/
ifi = if_indextoifinfo(pi->ipi6_ifindex);
if (ifi->ifi_rainfo == NULL) {
syslog(LOG_INFO,
"<%s> received RA from %s on non-advertising"
" interface(%s)",
__func__,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), if_indextoname(pi->ipi6_ifindex,
ifnamebuf));
goto done;
}
rai = ifi->ifi_rainfo;
ifi->ifi_rainput++;
syslog(LOG_DEBUG, "<%s> ifi->ifi_rainput = %" PRIu64, __func__,
ifi->ifi_rainput);
/* Cur Hop Limit value */
if (nra->nd_ra_curhoplimit && rai->rai_hoplimit &&
nra->nd_ra_curhoplimit != rai->rai_hoplimit) {
syslog(LOG_NOTICE,
"CurHopLimit inconsistent on %s:"
" %d from %s, %d from us",
ifi->ifi_ifname, nra->nd_ra_curhoplimit,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), rai->rai_hoplimit);
inconsistent++;
}
/* M flag */
if ((nra->nd_ra_flags_reserved & ND_RA_FLAG_MANAGED) !=
rai->rai_managedflg) {
syslog(LOG_NOTICE,
"M flag inconsistent on %s:"
" %s from %s, %s from us",
ifi->ifi_ifname, on_off[!rai->rai_managedflg],
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), on_off[rai->rai_managedflg]);
inconsistent++;
}
/* O flag */
if ((nra->nd_ra_flags_reserved & ND_RA_FLAG_OTHER) !=
rai->rai_otherflg) {
syslog(LOG_NOTICE,
"O flag inconsistent on %s:"
" %s from %s, %s from us",
ifi->ifi_ifname, on_off[!rai->rai_otherflg],
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), on_off[rai->rai_otherflg]);
inconsistent++;
}
#ifdef DRAFT_IETF_6MAN_IPV6ONLY_FLAG
/* 6 flag */
if ((nra->nd_ra_flags_reserved & ND_RA_FLAG_IPV6_ONLY) !=
rai->rai_ipv6onlyflg) {
syslog(LOG_NOTICE,
"6 flag inconsistent on %s:"
" %s from %s, %s from us",
ifi->ifi_ifname, on_off[!rai->rai_ipv6onlyflg],
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), on_off[rai->rai_ipv6onlyflg]);
inconsistent++;
}
#endif
/* Reachable Time */
reachabletime = ntohl(nra->nd_ra_reachable);
if (reachabletime && rai->rai_reachabletime &&
reachabletime != rai->rai_reachabletime) {
syslog(LOG_NOTICE,
"ReachableTime inconsistent on %s:"
" %d from %s, %d from us",
ifi->ifi_ifname, reachabletime,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), rai->rai_reachabletime);
inconsistent++;
}
/* Retrans Timer */
retranstimer = ntohl(nra->nd_ra_retransmit);
if (retranstimer && rai->rai_retranstimer &&
retranstimer != rai->rai_retranstimer) {
syslog(LOG_NOTICE,
"RetranceTimer inconsistent on %s:"
" %d from %s, %d from us",
ifi->ifi_ifname, retranstimer,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), rai->rai_retranstimer);
inconsistent++;
}
/* Values in the MTU options */
if (ndopts.opt_mtu) {
mtu = ntohl(ndopts.opt_mtu->nd_opt_mtu_mtu);
if (mtu && rai->rai_linkmtu && mtu != rai->rai_linkmtu) {
syslog(LOG_NOTICE,
"MTU option value inconsistent on %s:"
" %d from %s, %d from us",
ifi->ifi_ifname, mtu,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), rai->rai_linkmtu);
inconsistent++;
}
}
/* Preferred and Valid Lifetimes for prefixes */
{
struct nd_optlist *nol;
if (ndopts.opt_pi)
if (prefix_check(ndopts.opt_pi, rai, from))
inconsistent++;
TAILQ_FOREACH(nol, &ndopts.opt_list, nol_next)
if (prefix_check((struct nd_opt_prefix_info *)nol->nol_opt,
rai, from))
inconsistent++;
}
if (inconsistent)
ifi->ifi_rainconsistent++;
done:
free_ndopts(&ndopts);
return;
}
static uint32_t
udiff(uint32_t u, uint32_t v)
{
return (u >= v ? u - v : v - u);
}
/* return a non-zero value if the received prefix is inconsistent with ours */
static int
prefix_check(struct nd_opt_prefix_info *pinfo,
struct rainfo *rai, struct sockaddr_in6 *from)
{
struct ifinfo *ifi;
uint32_t preferred_time, valid_time;
struct prefix *pfx;
int inconsistent = 0;
char ntopbuf[INET6_ADDRSTRLEN];
char prefixbuf[INET6_ADDRSTRLEN];
struct timespec now;
#if 0 /* impossible */
if (pinfo->nd_opt_pi_type != ND_OPT_PREFIX_INFORMATION)
return (0);
#endif
ifi = rai->rai_ifinfo;
/*
* log if the adveritsed prefix has link-local scope(sanity check?)
*/
if (IN6_IS_ADDR_LINKLOCAL(&pinfo->nd_opt_pi_prefix))
syslog(LOG_INFO,
"<%s> link-local prefix %s/%d is advertised "
"from %s on %s",
__func__,
inet_ntop(AF_INET6, &pinfo->nd_opt_pi_prefix, prefixbuf,
sizeof(prefixbuf)),
pinfo->nd_opt_pi_prefix_len,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), ifi->ifi_ifname);
if ((pfx = find_prefix(rai, &pinfo->nd_opt_pi_prefix,
pinfo->nd_opt_pi_prefix_len)) == NULL) {
syslog(LOG_INFO,
"<%s> prefix %s/%d from %s on %s is not in our list",
__func__,
inet_ntop(AF_INET6, &pinfo->nd_opt_pi_prefix, prefixbuf,
sizeof(prefixbuf)),
pinfo->nd_opt_pi_prefix_len,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), ifi->ifi_ifname);
return (0);
}
preferred_time = ntohl(pinfo->nd_opt_pi_preferred_time);
if (pfx->pfx_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?
*/
clock_gettime(CLOCK_MONOTONIC_FAST, &now);
preferred_time += now.tv_sec;
if (!pfx->pfx_timer && rai->rai_clockskew &&
udiff(preferred_time, pfx->pfx_pltimeexpire) > rai->rai_clockskew) {
syslog(LOG_INFO,
"<%s> preferred lifetime for %s/%d"
" (decr. in real time) inconsistent on %s:"
" %" PRIu32 " from %s, %" PRIu32 " from us",
__func__,
inet_ntop(AF_INET6, &pinfo->nd_opt_pi_prefix, prefixbuf,
sizeof(prefixbuf)),
pinfo->nd_opt_pi_prefix_len,
ifi->ifi_ifname, preferred_time,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), pfx->pfx_pltimeexpire);
inconsistent++;
}
} else if (!pfx->pfx_timer && preferred_time != pfx->pfx_preflifetime)
syslog(LOG_INFO,
"<%s> preferred lifetime for %s/%d"
" inconsistent on %s:"
" %d from %s, %d from us",
__func__,
inet_ntop(AF_INET6, &pinfo->nd_opt_pi_prefix, prefixbuf,
sizeof(prefixbuf)),
pinfo->nd_opt_pi_prefix_len,
ifi->ifi_ifname, preferred_time,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), pfx->pfx_preflifetime);
valid_time = ntohl(pinfo->nd_opt_pi_valid_time);
if (pfx->pfx_vltimeexpire) {
clock_gettime(CLOCK_MONOTONIC_FAST, &now);
valid_time += now.tv_sec;
if (!pfx->pfx_timer && rai->rai_clockskew &&
udiff(valid_time, pfx->pfx_vltimeexpire) > rai->rai_clockskew) {
syslog(LOG_INFO,
"<%s> valid lifetime for %s/%d"
" (decr. in real time) inconsistent on %s:"
" %d from %s, %" PRIu32 " from us",
__func__,
inet_ntop(AF_INET6, &pinfo->nd_opt_pi_prefix, prefixbuf,
sizeof(prefixbuf)),
pinfo->nd_opt_pi_prefix_len,
ifi->ifi_ifname, preferred_time,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), pfx->pfx_vltimeexpire);
inconsistent++;
}
} else if (!pfx->pfx_timer && valid_time != pfx->pfx_validlifetime) {
syslog(LOG_INFO,
"<%s> valid lifetime for %s/%d"
" inconsistent on %s:"
" %d from %s, %d from us",
__func__,
inet_ntop(AF_INET6, &pinfo->nd_opt_pi_prefix, prefixbuf,
sizeof(prefixbuf)),
pinfo->nd_opt_pi_prefix_len,
ifi->ifi_ifname, valid_time,
inet_ntop(AF_INET6, &from->sin6_addr, ntopbuf,
sizeof(ntopbuf)), pfx->pfx_validlifetime);
inconsistent++;
}
return (inconsistent);
}
struct prefix *
find_prefix(struct rainfo *rai, struct in6_addr *prefix, int plen)
{
struct prefix *pfx;
int bytelen, bitlen;
char bitmask;
TAILQ_FOREACH(pfx, &rai->rai_prefix, pfx_next) {
if (plen != pfx->pfx_prefixlen)
continue;
bytelen = plen / 8;
bitlen = plen % 8;
bitmask = 0xff << (8 - bitlen);
if (memcmp((void *)prefix, (void *)&pfx->pfx_prefix, bytelen))
continue;
if (bitlen == 0 ||
((prefix->s6_addr[bytelen] & bitmask) ==
(pfx->pfx_prefix.s6_addr[bytelen] & bitmask))) {
return (pfx);
}
}
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;
char bitmask;
if (plen0 < plen1)
return (0);
bytelen = plen1 / 8;
bitlen = plen1 % 8;
bitmask = 0xff << (8 - bitlen);
if (memcmp((void *)p0, (void *)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_opt *ndopts, uint32_t optflags)
{
int optlen = 0;
for (; limit > 0; limit -= optlen) {
if ((size_t)limit < sizeof(struct nd_opt_hdr)) {
syslog(LOG_INFO, "<%s> short option header", __func__);
goto bad;
}
hdr = (struct nd_opt_hdr *)((caddr_t)hdr + optlen);
if (hdr->nd_opt_len == 0) {
syslog(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) {
syslog(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) {
syslog(LOG_INFO, "<%s> unknown ND option(type %d)",
__func__, hdr->nd_opt_type);
continue;
}
if ((ndopt_flags[hdr->nd_opt_type] & optflags) == 0) {
syslog(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.
*/
switch (hdr->nd_opt_type) {
case ND_OPT_MTU:
if (optlen == sizeof(struct nd_opt_mtu))
break;
goto skip;
case ND_OPT_RDNSS:
if (optlen >= 24 &&
(optlen - sizeof(struct nd_opt_rdnss)) % 16 == 0)
break;
goto skip;
case ND_OPT_DNSSL:
if (optlen >= 16 &&
(optlen - sizeof(struct nd_opt_dnssl)) % 8 == 0)
break;
goto skip;
case ND_OPT_PREFIX_INFORMATION:
if (optlen == sizeof(struct nd_opt_prefix_info))
break;
skip:
syslog(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->opt_array[hdr->nd_opt_type]) {
syslog(LOG_INFO,
"<%s> duplicated ND option (type = %d)",
__func__, hdr->nd_opt_type);
}
ndopts->opt_array[hdr->nd_opt_type] = hdr;
break;
case ND_OPT_PREFIX_INFORMATION:
{
struct nd_optlist *nol;
if (ndopts->opt_pi == 0) {
ndopts->opt_pi =
(struct nd_opt_prefix_info *)hdr;
continue;
}
nol = malloc(sizeof(*nol));
if (nol == NULL) {
syslog(LOG_ERR, "<%s> can't allocate memory",
__func__);
goto bad;
}
nol->nol_opt = hdr;
TAILQ_INSERT_TAIL(&(ndopts->opt_list), nol, nol_next);
break;
}
default: /* impossible */
break;
}
}
return (0);
bad:
free_ndopts(ndopts);
return (-1);
}
static void
free_ndopts(union nd_opt *ndopts)
{
struct nd_optlist *nol;
while ((nol = TAILQ_FIRST(&ndopts->opt_list)) != NULL) {
TAILQ_REMOVE(&ndopts->opt_list, nol, nol_next);
free(nol);
}
}
void
sock_open(struct sockinfo *s)
{
struct icmp6_filter filt;
int on;
/* XXX: should be max MTU attached to the node */
static char answer[1500];
syslog(LOG_DEBUG, "<%s> enter", __func__);
if (s == NULL) {
syslog(LOG_ERR, "<%s> internal error", __func__);
exit(1);
}
rcvcmsgbuflen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
CMSG_SPACE(sizeof(int));
rcvcmsgbuf = (char *)malloc(rcvcmsgbuflen);
if (rcvcmsgbuf == NULL) {
syslog(LOG_ERR, "<%s> not enough core", __func__);
exit(1);
}
sndcmsgbuflen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
CMSG_SPACE(sizeof(int));
sndcmsgbuf = (char *)malloc(sndcmsgbuflen);
if (sndcmsgbuf == NULL) {
syslog(LOG_ERR, "<%s> not enough core", __func__);
exit(1);
}
if ((s->si_fd = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
syslog(LOG_ERR, "<%s> socket: %s", __func__, strerror(errno));
exit(1);
}
/* specify to tell receiving interface */
on = 1;
if (setsockopt(s->si_fd, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
sizeof(on)) < 0) {
syslog(LOG_ERR, "<%s> IPV6_RECVPKTINFO: %s", __func__,
strerror(errno));
exit(1);
}
on = 1;
/* specify to tell value of hoplimit field of received IP6 hdr */
if (setsockopt(s->si_fd, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
sizeof(on)) < 0) {
syslog(LOG_ERR, "<%s> IPV6_RECVHOPLIMIT: %s", __func__,
strerror(errno));
exit(1);
}
ICMP6_FILTER_SETBLOCKALL(&filt);
ICMP6_FILTER_SETPASS(ND_ROUTER_SOLICIT, &filt);
ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
if (mcastif != NULL)
ICMP6_FILTER_SETPASS(ICMP6_ROUTER_RENUMBERING, &filt);
if (setsockopt(s->si_fd, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
sizeof(filt)) < 0) {
syslog(LOG_ERR, "<%s> IICMP6_FILTER: %s",
__func__, strerror(errno));
exit(1);
}
/* initialize msghdr for receiving packets */
rcviov[0].iov_base = (caddr_t)answer;
rcviov[0].iov_len = sizeof(answer);
rcvmhdr.msg_name = (caddr_t)&rcvfrom;
rcvmhdr.msg_namelen = sizeof(rcvfrom);
rcvmhdr.msg_iov = rcviov;
rcvmhdr.msg_iovlen = 1;
rcvmhdr.msg_control = (caddr_t) 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 = (caddr_t)sndcmsgbuf;
sndmhdr.msg_controllen = sndcmsgbuflen;
return;
}
/* open a routing socket to watch the routing table */
static void
rtsock_open(struct sockinfo *s)
{
if (s == NULL) {
syslog(LOG_ERR, "<%s> internal error", __func__);
exit(1);
}
if ((s->si_fd = socket(PF_ROUTE, SOCK_RAW, 0)) < 0) {
syslog(LOG_ERR,
"<%s> socket: %s", __func__, strerror(errno));
exit(1);
}
}
struct ifinfo *
if_indextoifinfo(int idx)
{
struct ifinfo *ifi;
char *name, name0[IFNAMSIZ];
/* Check if the interface has a valid name or not. */
if (if_indextoname(idx, name0) == NULL)
return (NULL);
TAILQ_FOREACH(ifi, &ifilist, ifi_next) {
if (ifi->ifi_ifindex == idx)
return (ifi);
}
if (ifi != NULL)
syslog(LOG_DEBUG, "<%s> ifi found (idx=%d)",
__func__, idx);
else
syslog(LOG_DEBUG, "<%s> ifi not found (idx=%d)",
__func__, idx);
return (NULL); /* search failed */
}
void
ra_output(struct ifinfo *ifi)
{
int i;
struct cmsghdr *cm;
struct in6_pktinfo *pi;
struct soliciter *sol;
struct rainfo *rai;
switch (ifi->ifi_state) {
case IFI_STATE_CONFIGURED:
rai = ifi->ifi_rainfo;
break;
case IFI_STATE_TRANSITIVE:
rai = ifi->ifi_rainfo_trans;
break;
case IFI_STATE_UNCONFIGURED:
syslog(LOG_DEBUG, "<%s> %s is unconfigured. "
"Skip sending RAs.",
__func__, ifi->ifi_ifname);
return;
default:
rai = NULL;
}
if (rai == NULL) {
syslog(LOG_DEBUG, "<%s> rainfo is NULL on %s."
"Skip sending RAs.",
__func__, ifi->ifi_ifname);
return;
}
if (!(ifi->ifi_flags & IFF_UP)) {
syslog(LOG_DEBUG, "<%s> %s is not up. "
"Skip sending RAs.",
__func__, ifi->ifi_ifname);
return;
}
/*
* Check lifetime, ACCEPT_RTADV flag, and ip6.forwarding.
*
* (lifetime == 0) = output
* (lifetime != 0 && (check_accept_rtadv()) = no output
*
* Basically, hosts MUST NOT send Router Advertisement
* messages at any time (RFC 4861, Section 6.2.3). However, it
* would sometimes be useful to allow hosts to advertise some
* parameters such as prefix information and link MTU. Thus,
* we allow hosts to invoke rtadvd only when router lifetime
* (on every advertising interface) is explicitly set
* zero. (see also the above section)
*/
syslog(LOG_DEBUG,
"<%s> check lifetime=%d, ACCEPT_RTADV=%d, ip6.forwarding=%d "
"on %s", __func__,
rai->rai_lifetime,
check_accept_rtadv(ifi->ifi_ifindex),
getinet6sysctl(IPV6CTL_FORWARDING),
ifi->ifi_ifname);
if (rai->rai_lifetime != 0) {
if (getinet6sysctl(IPV6CTL_FORWARDING) == 0) {
syslog(LOG_ERR,
"non-zero lifetime RA "
"but net.inet6.ip6.forwarding=0. "
"Ignored.");
return;
}
if (check_accept_rtadv(ifi->ifi_ifindex)) {
syslog(LOG_ERR,
"non-zero lifetime RA "
"on RA receiving interface %s."
" Ignored.", ifi->ifi_ifname);
return;
}
}
make_packet(rai); /* XXX: inefficient */
sndmhdr.msg_name = (caddr_t)&sin6_linklocal_allnodes;
sndmhdr.msg_iov[0].iov_base = (caddr_t)rai->rai_ra_data;
sndmhdr.msg_iov[0].iov_len = rai->rai_ra_datalen;
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 = ifi->ifi_ifindex;
/* specify the hop limit of the packet */
{
int hoplimit = 255;
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));
}
syslog(LOG_DEBUG,
"<%s> send RA on %s, # of RS waitings = %d",
__func__, ifi->ifi_ifname, ifi->ifi_rs_waitcount);
i = sendmsg(sock.si_fd, &sndmhdr, 0);
if (i < 0 || (size_t)i != rai->rai_ra_datalen) {
if (i < 0) {
syslog(LOG_ERR, "<%s> sendmsg on %s: %s",
__func__, ifi->ifi_ifname,
strerror(errno));
}
}
/*
* unicast advertisements
* XXX commented out. reason: though spec does not forbit it, unicast
* advert does not really help
*/
while ((sol = TAILQ_FIRST(&rai->rai_soliciter)) != NULL) {
TAILQ_REMOVE(&rai->rai_soliciter, sol, sol_next);
free(sol);
}
/* update timestamp */
clock_gettime(CLOCK_MONOTONIC_FAST, &ifi->ifi_ra_lastsent);
/* update counter */
ifi->ifi_rs_waitcount = 0;
ifi->ifi_raoutput++;
switch (ifi->ifi_state) {
case IFI_STATE_CONFIGURED:
if (ifi->ifi_burstcount > 0)
ifi->ifi_burstcount--;
break;
case IFI_STATE_TRANSITIVE:
ifi->ifi_burstcount--;
if (ifi->ifi_burstcount == 0) {
if (ifi->ifi_rainfo == ifi->ifi_rainfo_trans) {
/* Initial burst finished. */
if (ifi->ifi_rainfo_trans != NULL)
ifi->ifi_rainfo_trans = NULL;
}
/* Remove burst RA information */
if (ifi->ifi_rainfo_trans != NULL) {
rm_rainfo(ifi->ifi_rainfo_trans);
ifi->ifi_rainfo_trans = NULL;
}
if (ifi->ifi_rainfo != NULL) {
/*
* TRANSITIVE -> CONFIGURED
*
* After initial burst or transition from
* one configuration to another,
* ifi_rainfo always points to the next RA
* information.
*/
ifi->ifi_state = IFI_STATE_CONFIGURED;
syslog(LOG_DEBUG,
"<%s> ifname=%s marked as "
"CONFIGURED.", __func__,
ifi->ifi_ifname);
} else {
/*
* TRANSITIVE -> UNCONFIGURED
*
* If ifi_rainfo points to NULL, this
* interface is shutting down.
*
*/
int error;
ifi->ifi_state = IFI_STATE_UNCONFIGURED;
syslog(LOG_DEBUG,
"<%s> ifname=%s marked as "
"UNCONFIGURED.", __func__,
ifi->ifi_ifname);
error = sock_mc_leave(&sock,
ifi->ifi_ifindex);
if (error)
exit(1);
}
}
break;
}
}
/* process RA timer */
struct rtadvd_timer *
ra_timeout(void *arg)
{
struct ifinfo *ifi;
ifi = (struct ifinfo *)arg;
syslog(LOG_DEBUG, "<%s> RA timer on %s is expired",
__func__, ifi->ifi_ifname);
ra_output(ifi);
return (ifi->ifi_ra_timer);
}
/* update RA timer */
void
ra_timer_update(void *arg, struct timespec *tm)
{
uint16_t interval;
struct rainfo *rai;
struct ifinfo *ifi;
ifi = (struct ifinfo *)arg;
rai = ifi->ifi_rainfo;
interval = 0;
switch (ifi->ifi_state) {
case IFI_STATE_UNCONFIGURED:
return;
break;
case IFI_STATE_CONFIGURED:
/*
* 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 (RFC4861 6.2.4).
*/
interval = rai->rai_mininterval;
interval += arc4random_uniform(rai->rai_maxinterval -
rai->rai_mininterval);
break;
case IFI_STATE_TRANSITIVE:
/*
* 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
* 4861 6.2.4)
*
* In such cases, the router SHOULD transmit one or more
* (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
* multicast Router Advertisements on the interface with a
* Router Lifetime field of zero. (RFC 4861 6.2.5)
*/
interval = ifi->ifi_burstinterval;
break;
}
tm->tv_sec = interval;
tm->tv_nsec = 0;
syslog(LOG_DEBUG,
"<%s> RA timer on %s is set to %ld:%ld",
__func__, ifi->ifi_ifname,
(long int)tm->tv_sec, (long int)tm->tv_nsec / 1000);
return;
}
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