1
0
mirror of https://git.FreeBSD.org/src.git synced 2024-12-24 11:29:10 +00:00
freebsd/sbin/routed/rdisc.c
Pedro F. Giffuni 8a16b7a18f General further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 3-Clause license.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
2017-11-20 19:49:47 +00:00

1065 lines
25 KiB
C

/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1995
* The Regents of the University of California. 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 University 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 REGENTS 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 REGENTS 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.
*
* $FreeBSD$
*/
#include "defs.h"
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#ifdef __NetBSD__
__RCSID("$NetBSD$");
#elif defined(__FreeBSD__)
__RCSID("$FreeBSD$");
#else
__RCSID("$Revision: 2.27 $");
#ident "$Revision: 2.27 $"
#endif
/* router advertisement ICMP packet */
struct icmp_ad {
u_int8_t icmp_type; /* type of message */
u_int8_t icmp_code; /* type sub code */
u_int16_t icmp_cksum; /* ones complement cksum of struct */
u_int8_t icmp_ad_num; /* # of following router addresses */
u_int8_t icmp_ad_asize; /* 2--words in each advertisement */
u_int16_t icmp_ad_life; /* seconds of validity */
struct icmp_ad_info {
n_long icmp_ad_addr;
n_long icmp_ad_pref;
} icmp_ad_info[1];
};
/* router solicitation ICMP packet */
struct icmp_so {
u_int8_t icmp_type; /* type of message */
u_int8_t icmp_code; /* type sub code */
u_int16_t icmp_cksum; /* ones complement cksum of struct */
n_long icmp_so_rsvd;
};
union ad_u {
struct icmp icmp;
struct icmp_ad ad;
struct icmp_so so;
};
int rdisc_sock = -1; /* router-discovery raw socket */
static const struct interface *rdisc_sock_mcast; /* current multicast interface */
struct timeval rdisc_timer;
int rdisc_ok; /* using solicited route */
#define MAX_ADS 16 /* at least one per interface */
struct dr { /* accumulated advertisements */
struct interface *dr_ifp;
naddr dr_gate; /* gateway */
time_t dr_ts; /* when received */
time_t dr_life; /* lifetime in host byte order */
n_long dr_recv_pref; /* received but biased preference */
n_long dr_pref; /* preference adjusted by metric */
};
static const struct dr *cur_drp;
static struct dr drs[MAX_ADS];
/* convert between signed, balanced around zero,
* and unsigned zero-based preferences */
#define SIGN_PREF(p) ((p) ^ MIN_PreferenceLevel)
#define UNSIGN_PREF(p) SIGN_PREF(p)
/* adjust unsigned preference by interface metric,
* without driving it to infinity */
#define PREF(p, ifp) ((int)(p) <= ((ifp)->int_metric+(ifp)->int_adj_outmetric)\
? ((p) != 0 ? 1 : 0) \
: (p) - ((ifp)->int_metric+(ifp)->int_adj_outmetric))
static void rdisc_sort(void);
/* dump an ICMP Router Discovery Advertisement Message
*/
static void
trace_rdisc(const char *act,
naddr from,
naddr to,
struct interface *ifp,
union ad_u *p,
u_int len)
{
int i;
n_long *wp, *lim;
if (!TRACEPACKETS || ftrace == NULL)
return;
lastlog();
if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
(void)fprintf(ftrace, "%s Router Ad"
" from %s to %s via %s life=%d\n",
act, naddr_ntoa(from), naddr_ntoa(to),
ifp ? ifp->int_name : "?",
ntohs(p->ad.icmp_ad_life));
if (!TRACECONTENTS)
return;
wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
lim = &wp[(len - sizeof(p->ad)) / sizeof(*wp)];
for (i = 0; i < p->ad.icmp_ad_num && wp <= lim; i++) {
(void)fprintf(ftrace, "\t%s preference=%d",
naddr_ntoa(wp[0]), (int)ntohl(wp[1]));
wp += p->ad.icmp_ad_asize;
}
(void)fputc('\n',ftrace);
} else {
trace_act("%s Router Solic. from %s to %s via %s value=%#x",
act, naddr_ntoa(from), naddr_ntoa(to),
ifp ? ifp->int_name : "?",
(int)ntohl(p->so.icmp_so_rsvd));
}
}
/* prepare Router Discovery socket.
*/
static void
get_rdisc_sock(void)
{
if (rdisc_sock < 0) {
rdisc_sock = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
if (rdisc_sock < 0)
BADERR(1,"rdisc_sock = socket()");
fix_sock(rdisc_sock,"rdisc_sock");
fix_select();
}
}
/* Pick multicast group for router-discovery socket
*/
void
set_rdisc_mg(struct interface *ifp,
int on) /* 0=turn it off */
{
struct group_req gr;
struct sockaddr_in *sin;
assert(ifp != NULL);
if (rdisc_sock < 0) {
/* Create the raw socket so that we can hear at least
* broadcast router discovery packets.
*/
if ((ifp->int_state & IS_NO_RDISC) == IS_NO_RDISC
|| !on)
return;
get_rdisc_sock();
}
if (!(ifp->int_if_flags & IFF_MULTICAST)) {
ifp->int_state &= ~(IS_ALL_HOSTS | IS_ALL_ROUTERS);
return;
}
memset(&gr, 0, sizeof(gr));
gr.gr_interface = ifp->int_index;
sin = (struct sockaddr_in *)&gr.gr_group;
sin->sin_family = AF_INET;
#ifdef _HAVE_SIN_LEN
sin->sin_len = sizeof(struct sockaddr_in);
#endif
if (supplier
|| (ifp->int_state & IS_NO_ADV_IN)
|| !on) {
/* stop listening to advertisements
*/
if (ifp->int_state & IS_ALL_HOSTS) {
sin->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
if (setsockopt(rdisc_sock, IPPROTO_IP,
MCAST_LEAVE_GROUP,
&gr, sizeof(gr)) < 0)
LOGERR("MCAST_LEAVE_GROUP ALLHOSTS");
ifp->int_state &= ~IS_ALL_HOSTS;
}
} else if (!(ifp->int_state & IS_ALL_HOSTS)) {
/* start listening to advertisements
*/
sin->sin_addr.s_addr = htonl(INADDR_ALLHOSTS_GROUP);
if (setsockopt(rdisc_sock, IPPROTO_IP, MCAST_JOIN_GROUP,
&gr, sizeof(gr)) < 0) {
LOGERR("MCAST_JOIN_GROUP ALLHOSTS");
} else {
ifp->int_state |= IS_ALL_HOSTS;
}
}
if (!supplier
|| (ifp->int_state & IS_NO_ADV_OUT)
|| !on) {
/* stop listening to solicitations
*/
if (ifp->int_state & IS_ALL_ROUTERS) {
sin->sin_addr.s_addr = htonl(INADDR_ALLROUTERS_GROUP);
if (setsockopt(rdisc_sock, IPPROTO_IP,
MCAST_LEAVE_GROUP,
&gr, sizeof(gr)) < 0)
LOGERR("MCAST_LEAVE_GROUP ALLROUTERS");
ifp->int_state &= ~IS_ALL_ROUTERS;
}
} else if (!(ifp->int_state & IS_ALL_ROUTERS)) {
/* start hearing solicitations
*/
sin->sin_addr.s_addr = htonl(INADDR_ALLROUTERS_GROUP);
if (setsockopt(rdisc_sock, IPPROTO_IP, MCAST_JOIN_GROUP,
&gr, sizeof(gr)) < 0) {
LOGERR("MCAST_JOIN_GROUP ALLROUTERS");
} else {
ifp->int_state |= IS_ALL_ROUTERS;
}
}
}
/* start supplying routes
*/
void
set_supplier(void)
{
struct interface *ifp;
struct dr *drp;
if (supplier_set)
return;
trace_act("start supplying routes");
/* Forget discovered routes.
*/
for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
drp->dr_recv_pref = 0;
drp->dr_life = 0;
}
rdisc_age(0);
supplier_set = 1;
supplier = 1;
/* Do not start advertising until we have heard some RIP routes */
LIM_SEC(rdisc_timer, now.tv_sec+MIN_WAITTIME);
/* Switch router discovery multicast groups from soliciting
* to advertising.
*/
LIST_FOREACH(ifp, &ifnet, int_list) {
if (ifp->int_state & IS_BROKE)
continue;
ifp->int_rdisc_cnt = 0;
ifp->int_rdisc_timer.tv_usec = rdisc_timer.tv_usec;
ifp->int_rdisc_timer.tv_sec = now.tv_sec+MIN_WAITTIME;
set_rdisc_mg(ifp, 1);
}
/* get rid of any redirects */
del_redirects(0,0);
}
/* age discovered routes and find the best one
*/
void
rdisc_age(naddr bad_gate)
{
time_t sec;
struct dr *drp;
/* If only advertising, then do only that. */
if (supplier) {
/* If switching from client to server, get rid of old
* default routes.
*/
if (cur_drp != NULL)
rdisc_sort();
rdisc_adv();
return;
}
/* If we are being told about a bad router,
* then age the discovered default route, and if there is
* no alternative, solicit a replacement.
*/
if (bad_gate != 0) {
/* Look for the bad discovered default route.
* Age it and note its interface.
*/
for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
if (drp->dr_ts == 0)
continue;
/* When we find the bad router, then age the route
* to at most SUPPLY_INTERVAL.
* This is contrary to RFC 1256, but defends against
* black holes.
*/
if (drp->dr_gate == bad_gate) {
sec = (now.tv_sec - drp->dr_life
+ SUPPLY_INTERVAL);
if (drp->dr_ts > sec) {
trace_act("age 0.0.0.0 --> %s via %s",
naddr_ntoa(drp->dr_gate),
drp->dr_ifp->int_name);
drp->dr_ts = sec;
}
break;
}
}
}
rdisc_sol();
rdisc_sort();
/* Delete old redirected routes to keep the kernel table small,
* and to prevent black holes. Check that the kernel table
* matches the daemon table (i.e. has the default route).
* But only if RIP is not running and we are not dealing with
* a bad gateway, since otherwise age() will be called.
*/
if (rip_sock < 0 && bad_gate == 0)
age(0);
}
/* Zap all routes discovered via an interface that has gone bad
* This should only be called when !(ifp->int_state & IS_ALIAS)
*/
void
if_bad_rdisc(struct interface *ifp)
{
struct dr *drp;
for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
if (drp->dr_ifp != ifp)
continue;
drp->dr_recv_pref = 0;
drp->dr_ts = 0;
drp->dr_life = 0;
}
/* make a note to re-solicit, turn RIP on or off, etc. */
rdisc_timer.tv_sec = 0;
}
/* mark an interface ok for router discovering.
*/
void
if_ok_rdisc(struct interface *ifp)
{
set_rdisc_mg(ifp, 1);
ifp->int_rdisc_cnt = 0;
ifp->int_rdisc_timer.tv_sec = now.tv_sec + (supplier
? MIN_WAITTIME
: MAX_SOLICITATION_DELAY);
if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
rdisc_timer = ifp->int_rdisc_timer;
}
/* get rid of a dead discovered router
*/
static void
del_rdisc(struct dr *drp)
{
struct interface *ifp;
naddr gate;
int i;
del_redirects(gate = drp->dr_gate, 0);
drp->dr_ts = 0;
drp->dr_life = 0;
/* Count the other discovered routes on the interface.
*/
i = 0;
ifp = drp->dr_ifp;
for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
if (drp->dr_ts != 0
&& drp->dr_ifp == ifp)
i++;
}
/* If that was the last good discovered router on the interface,
* then solicit a new one.
* This is contrary to RFC 1256, but defends against black holes.
*/
if (i != 0) {
trace_act("discovered router %s via %s"
" is bad--have %d remaining",
naddr_ntoa(gate), ifp->int_name, i);
} else if (ifp->int_rdisc_cnt >= MAX_SOLICITATIONS) {
trace_act("last discovered router %s via %s"
" is bad--re-solicit",
naddr_ntoa(gate), ifp->int_name);
ifp->int_rdisc_cnt = 0;
ifp->int_rdisc_timer.tv_sec = 0;
rdisc_sol();
} else {
trace_act("last discovered router %s via %s"
" is bad--wait to solicit",
naddr_ntoa(gate), ifp->int_name);
}
}
/* Find the best discovered route,
* and discard stale routers.
*/
static void
rdisc_sort(void)
{
struct dr *drp, *new_drp;
struct rt_entry *rt;
struct rt_spare new;
struct interface *ifp;
u_int new_st = 0;
n_long new_pref = 0;
/* Find the best discovered route.
*/
new_drp = NULL;
for (drp = drs; drp < &drs[MAX_ADS]; drp++) {
if (drp->dr_ts == 0)
continue;
ifp = drp->dr_ifp;
/* Get rid of expired discovered routers.
*/
if (drp->dr_ts + drp->dr_life <= now.tv_sec) {
del_rdisc(drp);
continue;
}
LIM_SEC(rdisc_timer, drp->dr_ts+drp->dr_life+1);
/* Update preference with possibly changed interface
* metric.
*/
drp->dr_pref = PREF(drp->dr_recv_pref, ifp);
/* Prefer the current route to prevent thrashing.
* Prefer shorter lifetimes to speed the detection of
* bad routers.
* Avoid sick interfaces.
*/
if (new_drp == NULL
|| (!((new_st ^ drp->dr_ifp->int_state) & IS_SICK)
&& (new_pref < drp->dr_pref
|| (new_pref == drp->dr_pref
&& (drp == cur_drp
|| (new_drp != cur_drp
&& new_drp->dr_life > drp->dr_life)))))
|| ((new_st & IS_SICK)
&& !(drp->dr_ifp->int_state & IS_SICK))) {
new_drp = drp;
new_st = drp->dr_ifp->int_state;
new_pref = drp->dr_pref;
}
}
/* switch to a better default route
*/
if (new_drp != cur_drp) {
rt = rtget(RIP_DEFAULT, 0);
/* Stop using discovered routes if they are all bad
*/
if (new_drp == NULL) {
trace_act("turn off Router Discovery client");
rdisc_ok = 0;
if (rt != NULL
&& (rt->rt_state & RS_RDISC)) {
new = rt->rt_spares[0];
new.rts_metric = HOPCNT_INFINITY;
new.rts_time = now.tv_sec - GARBAGE_TIME;
rtchange(rt, rt->rt_state & ~RS_RDISC,
&new, 0);
rtswitch(rt, 0);
}
} else {
if (cur_drp == NULL) {
trace_act("turn on Router Discovery client"
" using %s via %s",
naddr_ntoa(new_drp->dr_gate),
new_drp->dr_ifp->int_name);
rdisc_ok = 1;
} else {
trace_act("switch Router Discovery from"
" %s via %s to %s via %s",
naddr_ntoa(cur_drp->dr_gate),
cur_drp->dr_ifp->int_name,
naddr_ntoa(new_drp->dr_gate),
new_drp->dr_ifp->int_name);
}
memset(&new, 0, sizeof(new));
new.rts_ifp = new_drp->dr_ifp;
new.rts_gate = new_drp->dr_gate;
new.rts_router = new_drp->dr_gate;
new.rts_metric = HOPCNT_INFINITY-1;
new.rts_time = now.tv_sec;
if (rt != NULL) {
rtchange(rt, rt->rt_state | RS_RDISC, &new, 0);
} else {
rtadd(RIP_DEFAULT, 0, RS_RDISC, &new);
}
}
cur_drp = new_drp;
}
/* turn RIP on or off */
if (!rdisc_ok || rip_interfaces > 1) {
rip_on(0);
} else {
rip_off();
}
}
/* handle a single address in an advertisement
*/
static void
parse_ad(naddr from,
naddr gate,
n_long pref, /* signed and in network order */
u_short life, /* in host byte order */
struct interface *ifp)
{
static struct msg_limit bad_gate;
struct dr *drp, *new_drp;
if (gate == RIP_DEFAULT
|| !check_dst(gate)) {
msglim(&bad_gate, from,"router %s advertising bad gateway %s",
naddr_ntoa(from),
naddr_ntoa(gate));
return;
}
/* ignore pointers to ourself and routes via unreachable networks
*/
if (ifwithaddr(gate, 1, 0) != NULL) {
trace_pkt(" discard Router Discovery Ad pointing at us");
return;
}
if (!on_net(gate, ifp->int_net, ifp->int_mask)) {
trace_pkt(" discard Router Discovery Ad"
" toward unreachable net");
return;
}
/* Convert preference to an unsigned value
* and later bias it by the metric of the interface.
*/
pref = UNSIGN_PREF(ntohl(pref));
if (pref == 0 || life < MinMaxAdvertiseInterval) {
pref = 0;
life = 0;
}
for (new_drp = NULL, drp = drs; drp < &drs[MAX_ADS]; drp++) {
/* accept new info for a familiar entry
*/
if (drp->dr_gate == gate) {
new_drp = drp;
break;
}
if (life == 0)
continue; /* do not worry about dead ads */
if (drp->dr_ts == 0) {
new_drp = drp; /* use unused entry */
} else if (new_drp == NULL) {
/* look for an entry worse than the new one to
* reuse.
*/
if ((!(ifp->int_state & IS_SICK)
&& (drp->dr_ifp->int_state & IS_SICK))
|| (pref > drp->dr_pref
&& !((ifp->int_state ^ drp->dr_ifp->int_state)
& IS_SICK)))
new_drp = drp;
} else if (new_drp->dr_ts != 0) {
/* look for the least valuable entry to reuse
*/
if ((!(new_drp->dr_ifp->int_state & IS_SICK)
&& (drp->dr_ifp->int_state & IS_SICK))
|| (new_drp->dr_pref > drp->dr_pref
&& !((new_drp->dr_ifp->int_state
^ drp->dr_ifp->int_state)
& IS_SICK)))
new_drp = drp;
}
}
/* forget it if all of the current entries are better */
if (new_drp == NULL)
return;
new_drp->dr_ifp = ifp;
new_drp->dr_gate = gate;
new_drp->dr_ts = now.tv_sec;
new_drp->dr_life = life;
new_drp->dr_recv_pref = pref;
/* bias functional preference by metric of the interface */
new_drp->dr_pref = PREF(pref,ifp);
/* after hearing a good advertisement, stop asking
*/
if (!(ifp->int_state & IS_SICK))
ifp->int_rdisc_cnt = MAX_SOLICITATIONS;
}
/* Compute the IP checksum
* This assumes the packet is less than 32K long.
*/
static u_short
in_cksum(u_short *p,
u_int len)
{
u_int sum = 0;
int nwords = len >> 1;
while (nwords-- != 0)
sum += *p++;
if (len & 1)
sum += *(u_char *)p;
/* end-around-carry */
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return (~sum);
}
/* Send a router discovery advertisement or solicitation ICMP packet.
*/
static void
send_rdisc(union ad_u *p,
int p_size,
struct interface *ifp,
naddr dst, /* 0 or unicast destination */
int type) /* 0=unicast, 1=bcast, 2=mcast */
{
struct sockaddr_in rsin;
int flags;
const char *msg;
memset(&rsin, 0, sizeof(rsin));
rsin.sin_addr.s_addr = dst;
rsin.sin_family = AF_INET;
#ifdef _HAVE_SIN_LEN
rsin.sin_len = sizeof(rsin);
#endif
flags = MSG_DONTROUTE;
switch (type) {
case 0: /* unicast */
default:
msg = "Send";
break;
case 1: /* broadcast */
if (ifp->int_if_flags & IFF_POINTOPOINT) {
msg = "Send pt-to-pt";
rsin.sin_addr.s_addr = ifp->int_dstaddr;
} else {
msg = "Send broadcast";
rsin.sin_addr.s_addr = ifp->int_brdaddr;
}
break;
case 2: /* multicast */
msg = "Send multicast";
if (ifp->int_state & IS_DUP) {
trace_act("abort multicast output via %s"
" with duplicate address",
ifp->int_name);
return;
}
if (rdisc_sock_mcast != ifp) {
/* select the right interface. */
struct ip_mreqn mreqn;
memset(&mreqn, 0, sizeof(struct ip_mreqn));
mreqn.imr_ifindex = ifp->int_index;
if (0 > setsockopt(rdisc_sock,
IPPROTO_IP, IP_MULTICAST_IF,
&mreqn,
sizeof(mreqn))) {
LOGERR("setsockopt(rdisc_sock,"
"IP_MULTICAST_IF)");
rdisc_sock_mcast = NULL;
return;
}
rdisc_sock_mcast = ifp;
}
flags = 0;
break;
}
if (rdisc_sock < 0)
get_rdisc_sock();
trace_rdisc(msg, (ifp ? ifp->int_addr : 0), rsin.sin_addr.s_addr, ifp,
p, p_size);
if (0 > sendto(rdisc_sock, p, p_size, flags,
(struct sockaddr *)&rsin, sizeof(rsin))) {
if (ifp == NULL || !(ifp->int_state & IS_BROKE))
msglog("sendto(%s%s%s): %s",
ifp != NULL ? ifp->int_name : "",
ifp != NULL ? ", " : "",
inet_ntoa(rsin.sin_addr),
strerror(errno));
if (ifp != NULL)
if_sick(ifp);
}
}
/* Send an advertisement
*/
static void
send_adv(struct interface *ifp,
naddr dst, /* 0 or unicast destination */
int type) /* 0=unicast, 1=bcast, 2=mcast */
{
union ad_u u;
n_long pref;
memset(&u, 0, sizeof(u.ad));
u.ad.icmp_type = ICMP_ROUTERADVERT;
u.ad.icmp_ad_num = 1;
u.ad.icmp_ad_asize = sizeof(u.ad.icmp_ad_info[0])/4;
u.ad.icmp_ad_life = stopint ? 0 : htons(ifp->int_rdisc_int*3);
/* Convert the configured preference to an unsigned value,
* bias it by the interface metric, and then send it as a
* signed, network byte order value.
*/
pref = UNSIGN_PREF(ifp->int_rdisc_pref);
u.ad.icmp_ad_info[0].icmp_ad_pref = htonl(SIGN_PREF(PREF(pref, ifp)));
u.ad.icmp_ad_info[0].icmp_ad_addr = ifp->int_addr;
u.ad.icmp_cksum = in_cksum((u_short*)&u.ad, sizeof(u.ad));
send_rdisc(&u, sizeof(u.ad), ifp, dst, type);
}
/* Advertise for Router Discovery
*/
void
rdisc_adv(void)
{
struct interface *ifp;
if (!supplier)
return;
rdisc_timer.tv_sec = now.tv_sec + NEVER;
LIST_FOREACH(ifp, &ifnet, int_list) {
if (0 != (ifp->int_state & (IS_NO_ADV_OUT | IS_BROKE)))
continue;
if (!timercmp(&ifp->int_rdisc_timer, &now, >)
|| stopint) {
send_adv(ifp, htonl(INADDR_ALLHOSTS_GROUP),
(ifp->int_state&IS_BCAST_RDISC) ? 1 : 2);
ifp->int_rdisc_cnt++;
intvl_random(&ifp->int_rdisc_timer,
(ifp->int_rdisc_int*3)/4,
ifp->int_rdisc_int);
if (ifp->int_rdisc_cnt < MAX_INITIAL_ADVERTS
&& (ifp->int_rdisc_timer.tv_sec
> MAX_INITIAL_ADVERT_INTERVAL)) {
ifp->int_rdisc_timer.tv_sec
= MAX_INITIAL_ADVERT_INTERVAL;
}
timevaladd(&ifp->int_rdisc_timer, &now);
}
if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
rdisc_timer = ifp->int_rdisc_timer;
}
}
/* Solicit for Router Discovery
*/
void
rdisc_sol(void)
{
struct interface *ifp;
union ad_u u;
if (supplier)
return;
rdisc_timer.tv_sec = now.tv_sec + NEVER;
LIST_FOREACH(ifp, &ifnet, int_list) {
if (0 != (ifp->int_state & (IS_NO_SOL_OUT | IS_BROKE))
|| ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
continue;
if (!timercmp(&ifp->int_rdisc_timer, &now, >)) {
memset(&u, 0, sizeof(u.so));
u.so.icmp_type = ICMP_ROUTERSOLICIT;
u.so.icmp_cksum = in_cksum((u_short*)&u.so,
sizeof(u.so));
send_rdisc(&u, sizeof(u.so), ifp,
htonl(INADDR_ALLROUTERS_GROUP),
((ifp->int_state&IS_BCAST_RDISC) ? 1 : 2));
if (++ifp->int_rdisc_cnt >= MAX_SOLICITATIONS)
continue;
ifp->int_rdisc_timer.tv_sec = SOLICITATION_INTERVAL;
ifp->int_rdisc_timer.tv_usec = 0;
timevaladd(&ifp->int_rdisc_timer, &now);
}
if (timercmp(&rdisc_timer, &ifp->int_rdisc_timer, >))
rdisc_timer = ifp->int_rdisc_timer;
}
}
/* check the IP header of a possible Router Discovery ICMP packet */
static struct interface * /* 0 if bad */
ck_icmp(const char *act,
naddr from,
struct interface *ifp,
naddr to,
union ad_u *p,
u_int len)
{
const char *type;
if (p->icmp.icmp_type == ICMP_ROUTERADVERT) {
type = "advertisement";
} else if (p->icmp.icmp_type == ICMP_ROUTERSOLICIT) {
type = "solicitation";
} else {
return 0;
}
if (p->icmp.icmp_code != 0) {
trace_pkt("unrecognized ICMP Router %s code=%d from %s to %s",
type, p->icmp.icmp_code,
naddr_ntoa(from), naddr_ntoa(to));
return 0;
}
trace_rdisc(act, from, to, ifp, p, len);
if (ifp == NULL)
trace_pkt("unknown interface for router-discovery %s"
" from %s to %s",
type, naddr_ntoa(from), naddr_ntoa(to));
return ifp;
}
/* read packets from the router discovery socket
*/
void
read_d(void)
{
static struct msg_limit bad_asize, bad_len;
#ifdef USE_PASSIFNAME
static struct msg_limit bad_name;
#endif
struct sockaddr_in from;
int n, fromlen, cc, hlen;
struct {
#ifdef USE_PASSIFNAME
char ifname[IFNAMSIZ];
#endif
union {
struct ip ip;
u_char b[512];
} pkt;
} buf;
union ad_u *p;
n_long *wp;
struct interface *ifp;
for (;;) {
fromlen = sizeof(from);
cc = recvfrom(rdisc_sock, &buf, sizeof(buf), 0,
(struct sockaddr*)&from,
&fromlen);
if (cc <= 0) {
if (cc < 0 && errno != EWOULDBLOCK)
LOGERR("recvfrom(rdisc_sock)");
break;
}
if (fromlen != sizeof(struct sockaddr_in))
logbad(1,"impossible recvfrom(rdisc_sock) fromlen=%d",
fromlen);
#ifdef USE_PASSIFNAME
if ((cc -= sizeof(buf.ifname)) < 0)
logbad(0,"missing USE_PASSIFNAME; only %d bytes",
cc+sizeof(buf.ifname));
#endif
hlen = buf.pkt.ip.ip_hl << 2;
if (cc < hlen + ICMP_MINLEN)
continue;
p = (union ad_u *)&buf.pkt.b[hlen];
cc -= hlen;
#ifdef USE_PASSIFNAME
ifp = ifwithname(buf.ifname, 0);
if (ifp == NULL)
msglim(&bad_name, from.sin_addr.s_addr,
"impossible rdisc if_ name %.*s",
IFNAMSIZ, buf.ifname);
#else
/* If we could tell the interface on which a packet from
* address 0 arrived, we could deal with such solicitations.
*/
ifp = ((from.sin_addr.s_addr == 0)
? 0 : iflookup(from.sin_addr.s_addr));
#endif
ifp = ck_icmp("Recv", from.sin_addr.s_addr, ifp,
buf.pkt.ip.ip_dst.s_addr, p, cc);
if (ifp == NULL)
continue;
if (ifwithaddr(from.sin_addr.s_addr, 0, 0)) {
trace_pkt(" "
"discard our own Router Discovery message");
continue;
}
switch (p->icmp.icmp_type) {
case ICMP_ROUTERADVERT:
if (p->ad.icmp_ad_asize*4
< (int)sizeof(p->ad.icmp_ad_info[0])) {
msglim(&bad_asize, from.sin_addr.s_addr,
"intolerable rdisc address size=%d",
p->ad.icmp_ad_asize);
continue;
}
if (p->ad.icmp_ad_num == 0) {
trace_pkt(" empty?");
continue;
}
if (cc != (int)(sizeof(p->ad)
- sizeof(p->ad.icmp_ad_info)
+ (p->ad.icmp_ad_num
* sizeof(p->ad.icmp_ad_info[0])))) {
msglim(&bad_len, from.sin_addr.s_addr,
"rdisc length %d does not match ad_num"
" %d", cc, p->ad.icmp_ad_num);
continue;
}
if (supplier)
continue;
if (ifp->int_state & IS_NO_ADV_IN)
continue;
wp = &p->ad.icmp_ad_info[0].icmp_ad_addr;
for (n = 0; n < p->ad.icmp_ad_num; n++) {
parse_ad(from.sin_addr.s_addr,
wp[0], wp[1],
ntohs(p->ad.icmp_ad_life),
ifp);
wp += p->ad.icmp_ad_asize;
}
break;
case ICMP_ROUTERSOLICIT:
if (!supplier)
continue;
if (ifp->int_state & IS_NO_ADV_OUT)
continue;
if (stopint)
continue;
/* XXX
* We should handle messages from address 0.
*/
/* Respond with a point-to-point advertisement */
send_adv(ifp, from.sin_addr.s_addr, 0);
break;
}
}
rdisc_sort();
}