/
nd6_rtr.c
2010 lines (1753 loc) · 55.1 KB
/
nd6_rtr.c
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/* $OpenBSD: nd6_rtr.c,v 1.55 2011/02/24 01:25:17 stsp Exp $ */
/* $KAME: nd6_rtr.c,v 1.97 2001/02/07 11:09:13 itojun 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/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <sys/queue.h>
#include <sys/workq.h>
#include <dev/rndvar.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/radix.h>
#include <netinet/in.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet/icmp6.h>
#include <dev/rndvar.h>
#define SDL(s) ((struct sockaddr_dl *)s)
int rtpref(struct nd_defrouter *);
struct nd_defrouter *defrtrlist_update(struct nd_defrouter *);
struct in6_ifaddr *in6_ifadd(struct nd_prefix *);
struct nd_pfxrouter *pfxrtr_lookup(struct nd_prefix *, struct nd_defrouter *);
void pfxrtr_add(struct nd_prefix *, struct nd_defrouter *);
void pfxrtr_del(struct nd_pfxrouter *);
struct nd_pfxrouter *find_pfxlist_reachable_router(struct nd_prefix *);
void defrouter_delreq(struct nd_defrouter *);
void nd6_rtmsg(int, struct rtentry *);
void purge_detached(struct ifnet *);
void in6_init_address_ltimes(struct nd_prefix *, struct in6_addrlifetime *);
int rt6_deleteroute(struct radix_node *, void *, u_int);
void nd6_addr_add(void *, void *);
extern int nd6_recalc_reachtm_interval;
static struct ifnet *nd6_defifp;
int nd6_defifindex;
/*
* Receive Router Solicitation Message - just for routers.
* Router solicitation/advertisement is mostly managed by userland program
* (rtadvd) so here we have no function like nd6_ra_output().
*
* Based on RFC 2461
*/
void
nd6_rs_input(struct mbuf *m, int off, int icmp6len)
{
struct ifnet *ifp = m->m_pkthdr.rcvif;
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
struct nd_router_solicit *nd_rs;
struct in6_addr saddr6 = ip6->ip6_src;
#if 0
struct in6_addr daddr6 = ip6->ip6_dst;
#endif
char *lladdr = NULL;
int lladdrlen = 0;
#if 0
struct sockaddr_dl *sdl = (struct sockaddr_dl *)NULL;
struct llinfo_nd6 *ln = (struct llinfo_nd6 *)NULL;
struct rtentry *rt = NULL;
int is_newentry;
#endif
union nd_opts ndopts;
/* If I'm not a router, ignore it. */
if (ip6_accept_rtadv != 0 || !ip6_forwarding)
goto freeit;
/* Sanity checks */
if (ip6->ip6_hlim != 255) {
nd6log((LOG_ERR,
"nd6_rs_input: invalid hlim (%d) from %s to %s on %s\n",
ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
ip6_sprintf(&ip6->ip6_dst), ifp->if_xname));
goto bad;
}
/*
* Don't update the neighbor cache, if src = ::.
* This indicates that the src has no IP address assigned yet.
*/
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
goto freeit;
IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off, icmp6len);
if (nd_rs == NULL) {
icmp6stat.icp6s_tooshort++;
return;
}
icmp6len -= sizeof(*nd_rs);
nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
if (nd6_options(&ndopts) < 0) {
nd6log((LOG_INFO,
"nd6_rs_input: invalid ND option, ignored\n"));
/* nd6_options have incremented stats */
goto freeit;
}
if (ndopts.nd_opts_src_lladdr) {
lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
}
if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
nd6log((LOG_INFO,
"nd6_rs_input: lladdrlen mismatch for %s "
"(if %d, RS packet %d)\n",
ip6_sprintf(&saddr6), ifp->if_addrlen, lladdrlen - 2));
goto bad;
}
nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_SOLICIT, 0);
freeit:
m_freem(m);
return;
bad:
icmp6stat.icp6s_badrs++;
m_freem(m);
}
/*
* Receive Router Advertisement Message.
*
* Based on RFC 2461
* TODO: on-link bit on prefix information
* TODO: ND_RA_FLAG_{OTHER,MANAGED} processing
*/
void
nd6_ra_input(struct mbuf *m, int off, int icmp6len)
{
struct ifnet *ifp = m->m_pkthdr.rcvif;
struct nd_ifinfo *ndi = ND_IFINFO(ifp);
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
struct nd_router_advert *nd_ra;
struct in6_addr saddr6 = ip6->ip6_src;
#if 0
struct in6_addr daddr6 = ip6->ip6_dst;
int flags; /* = nd_ra->nd_ra_flags_reserved; */
int is_managed = ((flags & ND_RA_FLAG_MANAGED) != 0);
int is_other = ((flags & ND_RA_FLAG_OTHER) != 0);
#endif
union nd_opts ndopts;
struct nd_defrouter *dr;
/*
* We only accept RAs only when
* the system-wide variable allows the acceptance, and
* per-interface variable allows RAs on the receiving interface.
*/
if (ip6_accept_rtadv == 0)
goto freeit;
if (!(ndi->flags & ND6_IFF_ACCEPT_RTADV))
goto freeit;
if (ip6->ip6_hlim != 255) {
nd6log((LOG_ERR,
"nd6_ra_input: invalid hlim (%d) from %s to %s on %s\n",
ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
ip6_sprintf(&ip6->ip6_dst), ifp->if_xname));
goto bad;
}
if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
nd6log((LOG_ERR,
"nd6_ra_input: src %s is not link-local\n",
ip6_sprintf(&saddr6)));
goto bad;
}
IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off, icmp6len);
if (nd_ra == NULL) {
icmp6stat.icp6s_tooshort++;
return;
}
icmp6len -= sizeof(*nd_ra);
nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
if (nd6_options(&ndopts) < 0) {
nd6log((LOG_INFO,
"nd6_ra_input: invalid ND option, ignored\n"));
/* nd6_options have incremented stats */
goto freeit;
}
{
struct nd_defrouter dr0;
u_int32_t advreachable = nd_ra->nd_ra_reachable;
Bzero(&dr0, sizeof(dr0));
dr0.rtaddr = saddr6;
dr0.flags = nd_ra->nd_ra_flags_reserved;
dr0.rtlifetime = ntohs(nd_ra->nd_ra_router_lifetime);
dr0.expire = time_second + dr0.rtlifetime;
dr0.ifp = ifp;
/* unspecified or not? (RFC 2461 6.3.4) */
if (advreachable) {
NTOHL(advreachable);
if (advreachable <= MAX_REACHABLE_TIME &&
ndi->basereachable != advreachable) {
ndi->basereachable = advreachable;
ndi->reachable = ND_COMPUTE_RTIME(ndi->basereachable);
ndi->recalctm = nd6_recalc_reachtm_interval; /* reset */
}
}
if (nd_ra->nd_ra_retransmit)
ndi->retrans = ntohl(nd_ra->nd_ra_retransmit);
if (nd_ra->nd_ra_curhoplimit)
ndi->chlim = nd_ra->nd_ra_curhoplimit;
dr = defrtrlist_update(&dr0);
}
/*
* prefix
*/
if (ndopts.nd_opts_pi) {
struct nd_opt_hdr *pt;
struct nd_opt_prefix_info *pi = NULL;
struct nd_prefix pr;
for (pt = (struct nd_opt_hdr *)ndopts.nd_opts_pi;
pt <= (struct nd_opt_hdr *)ndopts.nd_opts_pi_end;
pt = (struct nd_opt_hdr *)((caddr_t)pt +
(pt->nd_opt_len << 3))) {
if (pt->nd_opt_type != ND_OPT_PREFIX_INFORMATION)
continue;
pi = (struct nd_opt_prefix_info *)pt;
if (pi->nd_opt_pi_len != 4) {
nd6log((LOG_INFO,
"nd6_ra_input: invalid option "
"len %d for prefix information option, "
"ignored\n", pi->nd_opt_pi_len));
continue;
}
if (128 < pi->nd_opt_pi_prefix_len) {
nd6log((LOG_INFO,
"nd6_ra_input: invalid prefix "
"len %d for prefix information option, "
"ignored\n", pi->nd_opt_pi_prefix_len));
continue;
}
if (IN6_IS_ADDR_MULTICAST(&pi->nd_opt_pi_prefix)
|| IN6_IS_ADDR_LINKLOCAL(&pi->nd_opt_pi_prefix)) {
nd6log((LOG_INFO,
"nd6_ra_input: invalid prefix "
"%s, ignored\n",
ip6_sprintf(&pi->nd_opt_pi_prefix)));
continue;
}
/* aggregatable unicast address, rfc2374 */
if ((pi->nd_opt_pi_prefix.s6_addr8[0] & 0xe0) == 0x20
&& pi->nd_opt_pi_prefix_len != 64) {
nd6log((LOG_INFO,
"nd6_ra_input: invalid prefixlen "
"%d for rfc2374 prefix %s, ignored\n",
pi->nd_opt_pi_prefix_len,
ip6_sprintf(&pi->nd_opt_pi_prefix)));
continue;
}
bzero(&pr, sizeof(pr));
pr.ndpr_prefix.sin6_family = AF_INET6;
pr.ndpr_prefix.sin6_len = sizeof(pr.ndpr_prefix);
pr.ndpr_prefix.sin6_addr = pi->nd_opt_pi_prefix;
pr.ndpr_ifp = (struct ifnet *)m->m_pkthdr.rcvif;
pr.ndpr_raf_onlink = (pi->nd_opt_pi_flags_reserved &
ND_OPT_PI_FLAG_ONLINK) ? 1 : 0;
pr.ndpr_raf_auto = (pi->nd_opt_pi_flags_reserved &
ND_OPT_PI_FLAG_AUTO) ? 1 : 0;
pr.ndpr_plen = pi->nd_opt_pi_prefix_len;
pr.ndpr_vltime = ntohl(pi->nd_opt_pi_valid_time);
pr.ndpr_pltime = ntohl(pi->nd_opt_pi_preferred_time);
pr.ndpr_lastupdate = time_second;
if (in6_init_prefix_ltimes(&pr))
continue; /* prefix lifetime init failed */
(void)prelist_update(&pr, dr, m);
}
}
/*
* MTU
*/
if (ndopts.nd_opts_mtu && ndopts.nd_opts_mtu->nd_opt_mtu_len == 1) {
u_long mtu;
u_long maxmtu;
mtu = ntohl(ndopts.nd_opts_mtu->nd_opt_mtu_mtu);
/* lower bound */
if (mtu < IPV6_MMTU) {
nd6log((LOG_INFO, "nd6_ra_input: bogus mtu option "
"mtu=%lu sent from %s, ignoring\n",
mtu, ip6_sprintf(&ip6->ip6_src)));
goto skip;
}
/* upper bound */
maxmtu = (ndi->maxmtu && ndi->maxmtu < ifp->if_mtu)
? ndi->maxmtu : ifp->if_mtu;
if (mtu <= maxmtu) {
int change = (ndi->linkmtu != mtu);
ndi->linkmtu = mtu;
if (change) /* in6_maxmtu may change */
in6_setmaxmtu();
} else {
nd6log((LOG_INFO, "nd6_ra_input: bogus mtu "
"mtu=%lu sent from %s; "
"exceeds maxmtu %lu, ignoring\n",
mtu, ip6_sprintf(&ip6->ip6_src), maxmtu));
}
}
skip:
/*
* Source link layer address
*/
{
char *lladdr = NULL;
int lladdrlen = 0;
if (ndopts.nd_opts_src_lladdr) {
lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
}
if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
nd6log((LOG_INFO,
"nd6_ra_input: lladdrlen mismatch for %s "
"(if %d, RA packet %d)\n", ip6_sprintf(&saddr6),
ifp->if_addrlen, lladdrlen - 2));
goto bad;
}
nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_ROUTER_ADVERT, 0);
/*
* Installing a link-layer address might change the state of the
* router's neighbor cache, which might also affect our on-link
* detection of adveritsed prefixes.
*/
pfxlist_onlink_check();
}
freeit:
m_freem(m);
return;
bad:
icmp6stat.icp6s_badra++;
m_freem(m);
}
/*
* default router list processing sub routines
*/
/* tell the change to user processes watching the routing socket. */
void
nd6_rtmsg(int cmd, struct rtentry *rt)
{
struct rt_addrinfo info;
bzero((caddr_t)&info, sizeof(info));
info.rti_info[RTAX_DST] = rt_key(rt);
info.rti_info[RTAX_GATEWAY] = rt->rt_gateway;
info.rti_info[RTAX_NETMASK] = rt_mask(rt);
if (rt->rt_ifp) {
info.rti_info[RTAX_IFP] =
TAILQ_FIRST(&rt->rt_ifp->if_addrlist)->ifa_addr;
info.rti_info[RTAX_IFA] = rt->rt_ifa->ifa_addr;
}
rt_missmsg(cmd, &info, rt->rt_flags, rt->rt_ifp, 0, 0);
}
void
defrouter_addreq(struct nd_defrouter *new)
{
struct rt_addrinfo info;
struct sockaddr_in6 def, mask, gate;
struct rtentry *newrt = NULL;
int s;
int error;
Bzero(&def, sizeof(def));
Bzero(&mask, sizeof(mask));
Bzero(&gate, sizeof(gate)); /* for safety */
Bzero(&info, sizeof(info));
def.sin6_len = mask.sin6_len = gate.sin6_len =
sizeof(struct sockaddr_in6);
def.sin6_family = mask.sin6_family = gate.sin6_family = AF_INET6;
gate.sin6_addr = new->rtaddr;
gate.sin6_scope_id = 0; /* XXX */
info.rti_flags = RTF_GATEWAY;
info.rti_info[RTAX_DST] = (struct sockaddr *)&def;
info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&gate;
info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&mask;
s = splsoftnet();
error = rtrequest1(RTM_ADD, &info, RTP_CONNECTED, &newrt, 0);
if (newrt) {
nd6_rtmsg(RTM_ADD, newrt); /* tell user process */
newrt->rt_refcnt--;
}
if (error == 0)
new->installed = 1;
splx(s);
return;
}
struct nd_defrouter *
defrouter_lookup(struct in6_addr *addr, struct ifnet *ifp)
{
struct nd_defrouter *dr;
for (dr = TAILQ_FIRST(&nd_defrouter); dr;
dr = TAILQ_NEXT(dr, dr_entry)) {
if (dr->ifp == ifp && IN6_ARE_ADDR_EQUAL(addr, &dr->rtaddr)) {
return (dr);
}
}
return (NULL); /* search failed */
}
void
defrtrlist_del(struct nd_defrouter *dr)
{
struct nd_defrouter *deldr = NULL;
struct in6_ifextra *ext = dr->ifp->if_afdata[AF_INET6];
struct nd_prefix *pr;
/*
* Flush all the routing table entries that use the router
* as a next hop.
*/
if (!ip6_forwarding && ip6_accept_rtadv) /* XXX: better condition? */
rt6_flush(&dr->rtaddr, dr->ifp);
if (dr->installed) {
deldr = dr;
defrouter_delreq(dr);
}
TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
/*
* Also delete all the pointers to the router in each prefix lists.
*/
LIST_FOREACH(pr, &nd_prefix, ndpr_entry) {
struct nd_pfxrouter *pfxrtr;
if ((pfxrtr = pfxrtr_lookup(pr, dr)) != NULL)
pfxrtr_del(pfxrtr);
}
pfxlist_onlink_check();
/*
* If the router is the primary one, choose a new one.
* Note that defrouter_select() will remove the current gateway
* from the routing table.
*/
if (deldr)
defrouter_select();
ext->ndefrouters--;
if (ext->ndefrouters < 0) {
log(LOG_WARNING, "defrtrlist_del: negative count on %s\n",
dr->ifp->if_xname);
}
free(dr, M_IP6NDP);
}
/*
* Remove the default route for a given router.
* This is just a subroutine function for defrouter_select(), and should
* not be called from anywhere else.
*/
void
defrouter_delreq(struct nd_defrouter *dr)
{
struct rt_addrinfo info;
struct sockaddr_in6 def, mask, gw;
struct rtentry *oldrt = NULL;
#ifdef DIAGNOSTIC
if (!dr)
panic("dr == NULL in defrouter_delreq");
#endif
Bzero(&info, sizeof(info));
Bzero(&def, sizeof(def));
Bzero(&mask, sizeof(mask));
Bzero(&gw, sizeof(gw)); /* for safety */
def.sin6_len = mask.sin6_len = gw.sin6_len =
sizeof(struct sockaddr_in6);
def.sin6_family = mask.sin6_family = gw.sin6_family = AF_INET6;
gw.sin6_addr = dr->rtaddr;
gw.sin6_scope_id = 0; /* XXX */
info.rti_flags = RTF_GATEWAY;
info.rti_info[RTAX_DST] = (struct sockaddr *)&def;
info.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&gw;
info.rti_info[RTAX_NETMASK] = (struct sockaddr *)&mask;
rtrequest1(RTM_DELETE, &info, RTP_CONNECTED, &oldrt, 0);
if (oldrt) {
nd6_rtmsg(RTM_DELETE, oldrt);
if (oldrt->rt_refcnt <= 0) {
/*
* XXX: borrowed from the RTM_DELETE case of
* rtrequest1().
*/
oldrt->rt_refcnt++;
rtfree(oldrt);
}
}
dr->installed = 0;
}
/*
* remove all default routes from default router list
*/
void
defrouter_reset(void)
{
struct nd_defrouter *dr;
for (dr = TAILQ_FIRST(&nd_defrouter); dr;
dr = TAILQ_NEXT(dr, dr_entry))
defrouter_delreq(dr);
/*
* XXX should we also nuke any default routers in the kernel, by
* going through them by rtalloc1()?
*/
}
/*
* Default Router Selection according to Section 6.3.6 of RFC 2461 and
* draft-ietf-ipngwg-router-selection:
* 1) Routers that are reachable or probably reachable should be preferred.
* If we have more than one (probably) reachable router, prefer ones
* with the highest router preference.
* 2) When no routers on the list are known to be reachable or
* probably reachable, routers SHOULD be selected in a round-robin
* fashion, regardless of router preference values.
* 3) If the Default Router List is empty, assume that all
* destinations are on-link.
*
* We assume nd_defrouter is sorted by router preference value.
* Since the code below covers both with and without router preference cases,
* we do not need to classify the cases by ifdef.
*
* At this moment, we do not try to install more than one default router,
* even when the multipath routing is available, because we're not sure about
* the benefits for stub hosts comparing to the risk of making the code
* complicated and the possibility of introducing bugs.
*/
void
defrouter_select(void)
{
int s = splsoftnet();
struct nd_defrouter *dr, *selected_dr = NULL, *installed_dr = NULL;
struct rtentry *rt = NULL;
struct llinfo_nd6 *ln = NULL;
/*
* This function should be called only when acting as an autoconfigured
* host. Although the remaining part of this function is not effective
* if the node is not an autoconfigured host, we explicitly exclude
* such cases here for safety.
*/
if (ip6_forwarding || !ip6_accept_rtadv) {
nd6log((LOG_WARNING,
"defrouter_select: called unexpectedly (forwarding=%d, "
"accept_rtadv=%d)\n", ip6_forwarding, ip6_accept_rtadv));
splx(s);
return;
}
/*
* Let's handle easy case (3) first:
* If default router list is empty, there's nothing to be done.
*/
if (!TAILQ_FIRST(&nd_defrouter)) {
splx(s);
return;
}
/*
* Search for a (probably) reachable router from the list.
* We just pick up the first reachable one (if any), assuming that
* the ordering rule of the list described in defrtrlist_update().
*/
for (dr = TAILQ_FIRST(&nd_defrouter); dr;
dr = TAILQ_NEXT(dr, dr_entry)) {
if (!selected_dr &&
(rt = nd6_lookup(&dr->rtaddr, 0, dr->ifp)) &&
(ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
ND6_IS_LLINFO_PROBREACH(ln)) {
selected_dr = dr;
}
if (dr->installed && !installed_dr)
installed_dr = dr;
else if (dr->installed && installed_dr) {
/* this should not happen. warn for diagnosis. */
log(LOG_ERR, "defrouter_select: more than one router"
" is installed\n");
}
}
/*
* If none of the default routers was found to be reachable,
* round-robin the list regardless of preference.
* Otherwise, if we have an installed router, check if the selected
* (reachable) router should really be preferred to the installed one.
* We only prefer the new router when the old one is not reachable
* or when the new one has a really higher preference value.
*/
if (!selected_dr) {
if (!installed_dr || !TAILQ_NEXT(installed_dr, dr_entry))
selected_dr = TAILQ_FIRST(&nd_defrouter);
else
selected_dr = TAILQ_NEXT(installed_dr, dr_entry);
} else if (installed_dr &&
(rt = nd6_lookup(&installed_dr->rtaddr, 0, installed_dr->ifp)) &&
(ln = (struct llinfo_nd6 *)rt->rt_llinfo) &&
ND6_IS_LLINFO_PROBREACH(ln) &&
rtpref(selected_dr) <= rtpref(installed_dr)) {
selected_dr = installed_dr;
}
/*
* If the selected router is different than the installed one,
* remove the installed router and install the selected one.
* Note that the selected router is never NULL here.
*/
if (installed_dr != selected_dr) {
if (installed_dr)
defrouter_delreq(installed_dr);
defrouter_addreq(selected_dr);
}
splx(s);
return;
}
/*
* for default router selection
* regards router-preference field as a 2-bit signed integer
*/
int
rtpref(struct nd_defrouter *dr)
{
#ifdef RTPREF
switch (dr->flags & ND_RA_FLAG_RTPREF_MASK) {
case ND_RA_FLAG_RTPREF_HIGH:
return RTPREF_HIGH;
case ND_RA_FLAG_RTPREF_MEDIUM:
case ND_RA_FLAG_RTPREF_RSV:
return RTPREF_MEDIUM;
case ND_RA_FLAG_RTPREF_LOW:
return RTPREF_LOW;
default:
/*
* This case should never happen. If it did, it would mean a
* serious bug of kernel internal. We thus always bark here.
* Or, can we even panic?
*/
log(LOG_ERR, "rtpref: impossible RA flag %x", dr->flags);
return RTPREF_INVALID;
}
/* NOTREACHED */
#else
return 0;
#endif
}
struct nd_defrouter *
defrtrlist_update(struct nd_defrouter *new)
{
struct nd_defrouter *dr, *n;
struct in6_ifextra *ext = new->ifp->if_afdata[AF_INET6];
int s = splsoftnet();
if ((dr = defrouter_lookup(&new->rtaddr, new->ifp)) != NULL) {
/* entry exists */
if (new->rtlifetime == 0) {
defrtrlist_del(dr);
dr = NULL;
} else {
int oldpref = rtpref(dr);
/* override */
dr->flags = new->flags; /* xxx flag check */
dr->rtlifetime = new->rtlifetime;
dr->expire = new->expire;
if (!dr->installed)
defrouter_select();
/*
* If the preference does not change, there's no need
* to sort the entries.
*/
if (rtpref(new) == oldpref) {
splx(s);
return (dr);
}
/*
* preferred router may be changed, so relocate
* this router.
* XXX: calling TAILQ_REMOVE directly is a bad manner.
* However, since defrtrlist_del() has many side
* effects, we intentionally do so here.
* defrouter_select() below will handle routing
* changes later.
*/
TAILQ_REMOVE(&nd_defrouter, dr, dr_entry);
n = dr;
goto insert;
}
splx(s);
return (dr);
}
/* entry does not exist */
if (new->rtlifetime == 0) {
splx(s);
return (NULL);
}
if (ip6_maxifdefrouters >= 0 &&
ext->ndefrouters >= ip6_maxifdefrouters) {
splx(s);
return (NULL);
}
n = malloc(sizeof(*n), M_IP6NDP, M_NOWAIT | M_ZERO);
if (n == NULL) {
splx(s);
return (NULL);
}
*n = *new;
insert:
/*
* Insert the new router in the Default Router List;
* The Default Router List should be in the descending order
* of router-preference. Routers with the same preference are
* sorted in the arriving time order.
*/
/* insert at the end of the group */
for (dr = TAILQ_FIRST(&nd_defrouter); dr;
dr = TAILQ_NEXT(dr, dr_entry)) {
if (rtpref(n) > rtpref(dr))
break;
}
if (dr)
TAILQ_INSERT_BEFORE(dr, n, dr_entry);
else
TAILQ_INSERT_TAIL(&nd_defrouter, n, dr_entry);
defrouter_select();
ext->ndefrouters++;
splx(s);
return (n);
}
struct nd_pfxrouter *
pfxrtr_lookup(struct nd_prefix *pr, struct nd_defrouter *dr)
{
struct nd_pfxrouter *search;
LIST_FOREACH(search, &pr->ndpr_advrtrs, pfr_entry) {
if (search->router == dr)
break;
}
return (search);
}
void
pfxrtr_add(struct nd_prefix *pr, struct nd_defrouter *dr)
{
struct nd_pfxrouter *new;
new = malloc(sizeof(*new), M_IP6NDP, M_NOWAIT | M_ZERO);
if (new == NULL)
return;
new->router = dr;
LIST_INSERT_HEAD(&pr->ndpr_advrtrs, new, pfr_entry);
pfxlist_onlink_check();
}
void
pfxrtr_del(struct nd_pfxrouter *pfr)
{
LIST_REMOVE(pfr, pfr_entry);
free(pfr, M_IP6NDP);
}
struct nd_prefix *
nd6_prefix_lookup(struct nd_prefix *pr)
{
struct nd_prefix *search;
LIST_FOREACH(search, &nd_prefix, ndpr_entry) {
if (pr->ndpr_ifp == search->ndpr_ifp &&
pr->ndpr_plen == search->ndpr_plen &&
in6_are_prefix_equal(&pr->ndpr_prefix.sin6_addr,
&search->ndpr_prefix.sin6_addr, pr->ndpr_plen)) {
break;
}
}
return (search);
}
void
purge_detached(struct ifnet *ifp)
{
struct nd_prefix *pr, *pr_next;
struct in6_ifaddr *ia;
struct ifaddr *ifa, *ifa_next;
for (pr = nd_prefix.lh_first; pr; pr = pr_next) {
pr_next = pr->ndpr_next;
/*
* This function is called when we need to make more room for
* new prefixes rather than keeping old, possibly stale ones.
* Detached prefixes would be a good candidate; if all routers
* that advertised the prefix expired, the prefix is also
* probably stale.
*/
if (pr->ndpr_ifp != ifp ||
IN6_IS_ADDR_LINKLOCAL(&pr->ndpr_prefix.sin6_addr) ||
((pr->ndpr_stateflags & NDPRF_DETACHED) == 0 &&
!LIST_EMPTY(&pr->ndpr_advrtrs)))
continue;
for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = ifa_next) {
ifa_next = ifa->ifa_list.tqe_next;
if (ifa->ifa_addr->sa_family != AF_INET6)
continue;
ia = (struct in6_ifaddr *)ifa;
if ((ia->ia6_flags & IN6_IFF_AUTOCONF) ==
IN6_IFF_AUTOCONF && ia->ia6_ndpr == pr) {
in6_purgeaddr(ifa);
}
}
if (pr->ndpr_refcnt == 0)
prelist_remove(pr);
}
}
int
nd6_prelist_add(struct nd_prefix *pr, struct nd_defrouter *dr,
struct nd_prefix **newp)
{
struct nd_prefix *new = NULL;
int i, s;
struct in6_ifextra *ext = pr->ndpr_ifp->if_afdata[AF_INET6];
if (ip6_maxifprefixes >= 0) {
if (ext->nprefixes >= ip6_maxifprefixes / 2)
purge_detached(pr->ndpr_ifp);
if (ext->nprefixes >= ip6_maxifprefixes)
return(ENOMEM);
}
new = malloc(sizeof(*new), M_IP6NDP, M_NOWAIT | M_ZERO);
if (new == NULL)
return ENOMEM;
*new = *pr;
if (newp != NULL)
*newp = new;
/* initialization */
LIST_INIT(&new->ndpr_advrtrs);
in6_prefixlen2mask(&new->ndpr_mask, new->ndpr_plen);
/* make prefix in the canonical form */
for (i = 0; i < 4; i++)
new->ndpr_prefix.sin6_addr.s6_addr32[i] &=
new->ndpr_mask.s6_addr32[i];
s = splsoftnet();
/* link ndpr_entry to nd_prefix list */
LIST_INSERT_HEAD(&nd_prefix, new, ndpr_entry);
splx(s);
/* ND_OPT_PI_FLAG_ONLINK processing */
if (new->ndpr_raf_onlink) {
int e;
if ((e = nd6_prefix_onlink(new)) != 0) {
nd6log((LOG_ERR, "nd6_prelist_add: failed to make "
"the prefix %s/%d on-link on %s (errno=%d)\n",
ip6_sprintf(&pr->ndpr_prefix.sin6_addr),
pr->ndpr_plen, pr->ndpr_ifp->if_xname, e));
/* proceed anyway. XXX: is it correct? */
}
}
if (dr)
pfxrtr_add(new, dr);
ext->nprefixes++;
return 0;
}
void
prelist_remove(struct nd_prefix *pr)
{
struct nd_pfxrouter *pfr, *next;
int e, s;
struct in6_ifextra *ext = pr->ndpr_ifp->if_afdata[AF_INET6];
/* make sure to invalidate the prefix until it is really freed. */
pr->ndpr_vltime = 0;
pr->ndpr_pltime = 0;
#if 0
/*
* Though these flags are now meaningless, we'd rather keep the value
* not to confuse users when executing "ndp -p".
*/
pr->ndpr_raf_onlink = 0;