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src/sys/netinet6/nd6.c

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/* $OpenBSD: nd6.c,v 1.282 2024/07/14 18:53:39 bluhm Exp $ */
/* $KAME: nd6.c,v 1.280 2002/06/08 19:52:07 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/timeout.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/pool.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <sys/queue.h>
#include <sys/stdint.h>
#include <sys/task.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/ip_ipsp.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>
#include <netinet/icmp6.h>
/*
* Locks used to protect struct members in this file:
* a atomic operations
* I immutable after creation
* K kernel lock
* m nd6 mutex, needed when net lock is shared
* N net lock
*/
#define ND6_SLOWTIMER_INTERVAL (60 * 60) /* 1 hour */
#define ND6_RECALC_REACHTM_INTERVAL (60 * 120) /* 2 hours */
/* timer values */
int nd6_timer_next = -1; /* at which uptime nd6_timer runs */
time_t nd6_expire_next = -1; /* at which uptime nd6_expire runs */
int nd6_delay = 5; /* delay first probe time 5 second */
int nd6_umaxtries = 3; /* maximum unicast query */
int nd6_mmaxtries = 3; /* maximum multicast query */
int nd6_gctimer = (60 * 60 * 24); /* 1 day: garbage collection timer */
/* preventing too many loops in ND option parsing */
int nd6_maxndopt = 10; /* max # of ND options allowed */
int nd6_maxnudhint = 0; /* max # of subsequent upper layer hints */
#ifdef ND6_DEBUG
int nd6_debug = 1;
#else
int nd6_debug = 0;
#endif
/* llinfo_nd6 live time, rt_llinfo and RTF_LLINFO are protected by nd6_mtx */
struct mutex nd6_mtx = MUTEX_INITIALIZER(IPL_SOFTNET);
TAILQ_HEAD(llinfo_nd6_head, llinfo_nd6) nd6_list =
TAILQ_HEAD_INITIALIZER(nd6_list); /* [mN] list of llinfo_nd6 structures */
struct pool nd6_pool; /* [I] pool for llinfo_nd6 structures */
int nd6_inuse; /* [m] limit neigbor discovery routes */
unsigned int ln_hold_total; /* [a] packets currently in the nd6 queue */
void nd6_timer(void *);
void nd6_slowtimo(void *);
void nd6_expire(void *);
void nd6_expire_timer(void *);
void nd6_invalidate(struct rtentry *);
void nd6_free(struct rtentry *, int);
int nd6_llinfo_timer(struct rtentry *, int);
struct timeout nd6_timer_to;
struct timeout nd6_slowtimo_ch;
struct timeout nd6_expire_timeout;
struct task nd6_expire_task;
void
nd6_init(void)
{
pool_init(&nd6_pool, sizeof(struct llinfo_nd6), 0,
IPL_SOFTNET, 0, "nd6", NULL);
task_set(&nd6_expire_task, nd6_expire, NULL);
/* start timer */
timeout_set_proc(&nd6_timer_to, nd6_timer, NULL);
timeout_set_proc(&nd6_slowtimo_ch, nd6_slowtimo, NULL);
timeout_add_sec(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL);
timeout_set(&nd6_expire_timeout, nd6_expire_timer, NULL);
}
void
nd6_ifattach(struct ifnet *ifp)
{
struct nd_ifinfo *nd;
nd = malloc(sizeof(*nd), M_IP6NDP, M_WAITOK | M_ZERO);
nd->reachable = ND_COMPUTE_RTIME(REACHABLE_TIME);
ifp->if_nd = nd;
}
void
nd6_ifdetach(struct ifnet *ifp)
{
struct nd_ifinfo *nd = ifp->if_nd;
free(nd, M_IP6NDP, sizeof(*nd));
}
/*
* Parse multiple ND options.
* This function is much easier to use, for ND routines that do not need
* multiple options of the same type.
*/
int
nd6_options(void *opt, int icmp6len, struct nd_opts *ndopts)
{
struct nd_opt_hdr *nd_opt, *next_opt, *last_opt;
int i = 0;
bzero(ndopts, sizeof(*ndopts));
if (icmp6len == 0)
return 0;
next_opt = opt;
last_opt = (struct nd_opt_hdr *)((u_char *)opt + icmp6len);
while (next_opt != NULL) {
int olen;
nd_opt = next_opt;
/* make sure nd_opt_len is inside the buffer */
if ((caddr_t)&nd_opt->nd_opt_len >= (caddr_t)last_opt)
goto invalid;
/* every option must have a length greater than zero */
olen = nd_opt->nd_opt_len << 3;
if (olen == 0)
goto invalid;
next_opt = (struct nd_opt_hdr *)((caddr_t)nd_opt + olen);
if (next_opt > last_opt) {
/* option overruns the end of buffer */
goto invalid;
} else if (next_opt == last_opt) {
/* reached the end of options chain */
next_opt = NULL;
}
switch (nd_opt->nd_opt_type) {
case ND_OPT_SOURCE_LINKADDR:
if (ndopts->nd_opts_src_lladdr != NULL)
nd6log((LOG_INFO, "duplicated ND6 option found "
"(type=%d)\n", nd_opt->nd_opt_type));
else
ndopts->nd_opts_src_lladdr = nd_opt;
break;
case ND_OPT_TARGET_LINKADDR:
if (ndopts->nd_opts_tgt_lladdr != NULL)
nd6log((LOG_INFO, "duplicated ND6 option found "
"(type=%d)\n", nd_opt->nd_opt_type));
else
ndopts->nd_opts_tgt_lladdr = nd_opt;
break;
case ND_OPT_MTU:
case ND_OPT_REDIRECTED_HEADER:
case ND_OPT_PREFIX_INFORMATION:
case ND_OPT_DNSSL:
case ND_OPT_RDNSS:
/* Don't warn, not used by kernel */
break;
default:
/*
* Unknown options must be silently ignored,
* to accommodate future extension to the protocol.
*/
nd6log((LOG_DEBUG,
"nd6_options: unsupported option %d - "
"option ignored\n", nd_opt->nd_opt_type));
break;
}
i++;
if (i > nd6_maxndopt) {
icmp6stat_inc(icp6s_nd_toomanyopt);
nd6log((LOG_INFO, "too many loop in nd opt\n"));
break;
}
}
return 0;
invalid:
bzero(ndopts, sizeof(*ndopts));
icmp6stat_inc(icp6s_nd_badopt);
return -1;
}
/*
* ND6 timer routine to handle ND6 entries
*/
void
nd6_llinfo_settimer(const struct llinfo_nd6 *ln, unsigned int secs)
{
time_t expire = getuptime() + secs;
NET_ASSERT_LOCKED();
KASSERT(!ISSET(ln->ln_rt->rt_flags, RTF_LOCAL));
ln->ln_rt->rt_expire = expire;
if (!timeout_pending(&nd6_timer_to) || expire < nd6_timer_next) {
nd6_timer_next = expire;
timeout_add_sec(&nd6_timer_to, secs);
}
}
void
nd6_timer(void *unused)
{
struct llinfo_nd6 *ln, *nln;
time_t uptime, expire;
int i_am_router = (atomic_load_int(&ip6_forwarding) != 0);
int secs;
NET_LOCK();
uptime = getuptime();
expire = uptime + nd6_gctimer;
/* Net lock is exclusive, no nd6 mutex needed for nd6_list here. */
TAILQ_FOREACH_SAFE(ln, &nd6_list, ln_list, nln) {
struct rtentry *rt = ln->ln_rt;
if (rt->rt_expire && rt->rt_expire <= uptime)
if (nd6_llinfo_timer(rt, i_am_router))
continue;
if (rt->rt_expire && rt->rt_expire < expire)
expire = rt->rt_expire;
}
secs = expire - uptime;
if (secs < 0)
secs = 0;
if (!TAILQ_EMPTY(&nd6_list)) {
nd6_timer_next = uptime + secs;
timeout_add_sec(&nd6_timer_to, secs);
}
NET_UNLOCK();
}
/*
* ND timer state handling.
*
* Returns 1 if `rt' should no longer be used, 0 otherwise.
*/
int
nd6_llinfo_timer(struct rtentry *rt, int i_am_router)
{
struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo;
struct sockaddr_in6 *dst = satosin6(rt_key(rt));
struct ifnet *ifp;
NET_ASSERT_LOCKED_EXCLUSIVE();
if ((ifp = if_get(rt->rt_ifidx)) == NULL)
return 1;
switch (ln->ln_state) {
case ND6_LLINFO_INCOMPLETE:
if (ln->ln_asked < nd6_mmaxtries) {
ln->ln_asked++;
nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000);
nd6_ns_output(ifp, NULL, &dst->sin6_addr,
&ln->ln_saddr6, 0);
} else {
struct mbuf_list ml;
struct mbuf *m;
unsigned int len;
mq_delist(&ln->ln_mq, &ml);
len = ml_len(&ml);
while ((m = ml_dequeue(&ml)) != NULL) {
/*
* Fake rcvif to make the ICMP error
* more helpful in diagnosing for the
* receiver.
* XXX: should we consider older rcvif?
*/
m->m_pkthdr.ph_ifidx = rt->rt_ifidx;
icmp6_error(m, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_ADDR, 0);
}
/* XXXSMP we also discard if other CPU enqueues */
if (mq_len(&ln->ln_mq) > 0) {
/* mbuf is back in queue. Discard. */
atomic_sub_int(&ln_hold_total,
len + mq_purge(&ln->ln_mq));
} else
atomic_sub_int(&ln_hold_total, len);
nd6_free(rt, i_am_router);
ln = NULL;
}
break;
case ND6_LLINFO_REACHABLE:
if (!ND6_LLINFO_PERMANENT(ln)) {
ln->ln_state = ND6_LLINFO_STALE;
nd6_llinfo_settimer(ln, nd6_gctimer);
}
break;
case ND6_LLINFO_STALE:
case ND6_LLINFO_PURGE:
/* Garbage Collection(RFC 2461 5.3) */
if (!ND6_LLINFO_PERMANENT(ln)) {
nd6_free(rt, i_am_router);
ln = NULL;
}
break;
case ND6_LLINFO_DELAY:
/* We need NUD */
ln->ln_asked = 1;
ln->ln_state = ND6_LLINFO_PROBE;
nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000);
nd6_ns_output(ifp, &dst->sin6_addr, &dst->sin6_addr,
&ln->ln_saddr6, 0);
break;
case ND6_LLINFO_PROBE:
if (ln->ln_asked < nd6_umaxtries) {
ln->ln_asked++;
nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000);
nd6_ns_output(ifp, &dst->sin6_addr, &dst->sin6_addr,
&ln->ln_saddr6, 0);
} else {
nd6_free(rt, i_am_router);
ln = NULL;
}
break;
}
if_put(ifp);
return (ln == NULL);
}
void
nd6_expire_timer_update(struct in6_ifaddr *ia6)
{
time_t expire_time = INT64_MAX;
if (ia6->ia6_lifetime.ia6t_vltime != ND6_INFINITE_LIFETIME)
expire_time = ia6->ia6_lifetime.ia6t_expire;
if (!(ia6->ia6_flags & IN6_IFF_DEPRECATED) &&
ia6->ia6_lifetime.ia6t_pltime != ND6_INFINITE_LIFETIME &&
expire_time > ia6->ia6_lifetime.ia6t_preferred)
expire_time = ia6->ia6_lifetime.ia6t_preferred;
if (expire_time == INT64_MAX)
return;
/*
* IFA6_IS_INVALID() and IFA6_IS_DEPRECATED() check for uptime
* greater than ia6t_expire or ia6t_preferred, not greater or equal.
* Schedule timeout one second later so that either IFA6_IS_INVALID()
* or IFA6_IS_DEPRECATED() is true.
*/
expire_time++;
if (!timeout_pending(&nd6_expire_timeout) ||
nd6_expire_next > expire_time) {
int secs;
secs = expire_time - getuptime();
if (secs < 0)
secs = 0;
timeout_add_sec(&nd6_expire_timeout, secs);
nd6_expire_next = expire_time;
}
}
/*
* Expire interface addresses.
*/
void
nd6_expire(void *unused)
{
struct ifnet *ifp;
NET_LOCK();
TAILQ_FOREACH(ifp, &ifnetlist, if_list) {
struct ifaddr *ifa, *nifa;
struct in6_ifaddr *ia6;
TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrlist, ifa_list, nifa) {
if (ifa->ifa_addr->sa_family != AF_INET6)
continue;
ia6 = ifatoia6(ifa);
/* check address lifetime */
if (IFA6_IS_INVALID(ia6)) {
in6_purgeaddr(&ia6->ia_ifa);
} else {
if (IFA6_IS_DEPRECATED(ia6))
ia6->ia6_flags |= IN6_IFF_DEPRECATED;
nd6_expire_timer_update(ia6);
}
}
}
NET_UNLOCK();
}
void
nd6_expire_timer(void *unused)
{
task_add(net_tq(0), &nd6_expire_task);
}
/*
* Nuke neighbor cache/prefix/default router management table, right before
* ifp goes away.
*/
void
nd6_purge(struct ifnet *ifp)
{
struct llinfo_nd6 *ln, *nln;
int i_am_router = (atomic_load_int(&ip6_forwarding) != 0);
NET_ASSERT_LOCKED_EXCLUSIVE();
/*
* Nuke neighbor cache entries for the ifp.
*/
TAILQ_FOREACH_SAFE(ln, &nd6_list, ln_list, nln) {
struct rtentry *rt;
struct sockaddr_dl *sdl;
rt = ln->ln_rt;
if (rt != NULL && rt->rt_gateway != NULL &&
rt->rt_gateway->sa_family == AF_LINK) {
sdl = satosdl(rt->rt_gateway);
if (sdl->sdl_index == ifp->if_index)
nd6_free(rt, i_am_router);
}
}
}
struct rtentry *
nd6_lookup(const struct in6_addr *addr6, int create, struct ifnet *ifp,
u_int rtableid)
{
struct rtentry *rt;
struct sockaddr_in6 sin6;
int flags;
bzero(&sin6, sizeof(sin6));
sin6.sin6_len = sizeof(struct sockaddr_in6);
sin6.sin6_family = AF_INET6;
sin6.sin6_addr = *addr6;
flags = (create) ? RT_RESOLVE : 0;
rt = rtalloc(sin6tosa(&sin6), flags, rtableid);
if (rt != NULL && (rt->rt_flags & RTF_LLINFO) == 0) {
/*
* This is the case for the default route.
* If we want to create a neighbor cache for the address, we
* should free the route for the destination and allocate an
* interface route.
*/
if (create) {
rtfree(rt);
rt = NULL;
}
}
if (rt == NULL) {
if (create && ifp) {
struct rt_addrinfo info;
struct llinfo_nd6 *ln;
struct ifaddr *ifa;
int error;
/*
* If no route is available and create is set,
* we allocate a host route for the destination
* and treat it like an interface route.
* This hack is necessary for a neighbor which can't
* be covered by our own prefix.
*/
ifa = ifaof_ifpforaddr(sin6tosa(&sin6), ifp);
if (ifa == NULL)
return (NULL);
/*
* Create a new route. RTF_LLINFO is necessary
* to create a Neighbor Cache entry for the
* destination in nd6_rtrequest which will be
* called in rtrequest.
*/
bzero(&info, sizeof(info));
info.rti_ifa = ifa;
info.rti_flags = RTF_HOST | RTF_LLINFO;
info.rti_info[RTAX_DST] = sin6tosa(&sin6);
info.rti_info[RTAX_GATEWAY] = sdltosa(ifp->if_sadl);
error = rtrequest(RTM_ADD, &info, RTP_CONNECTED, &rt,
rtableid);
if (error)
return (NULL);
mtx_enter(&nd6_mtx);
ln = (struct llinfo_nd6 *)rt->rt_llinfo;
if (ln != NULL)
ln->ln_state = ND6_LLINFO_NOSTATE;
mtx_leave(&nd6_mtx);
} else
return (NULL);
}
/*
* Validation for the entry.
* Note that the check for rt_llinfo is necessary because a cloned
* route from a parent route that has the L flag (e.g. the default
* route to a p2p interface) may have the flag, too, while the
* destination is not actually a neighbor.
*/
if ((rt->rt_flags & RTF_GATEWAY) || (rt->rt_flags & RTF_LLINFO) == 0 ||
rt->rt_gateway->sa_family != AF_LINK || rt->rt_llinfo == NULL ||
(ifp != NULL && rt->rt_ifidx != ifp->if_index)) {
if (create) {
char addr[INET6_ADDRSTRLEN];
nd6log((LOG_DEBUG, "%s: failed to lookup %s (if=%s)\n",
__func__,
inet_ntop(AF_INET6, addr6, addr, sizeof(addr)),
ifp ? ifp->if_xname : "unspec"));
}
rtfree(rt);
return (NULL);
}
return (rt);
}
/*
* Detect if a given IPv6 address identifies a neighbor on a given link.
* XXX: should take care of the destination of a p2p link?
*/
int
nd6_is_addr_neighbor(const struct sockaddr_in6 *addr, struct ifnet *ifp)
{
struct in6_ifaddr *ia6;
struct ifaddr *ifa;
struct rtentry *rt;
/*
* A link-local address is always a neighbor.
* XXX: we should use the sin6_scope_id field rather than the embedded
* interface index.
* XXX: a link does not necessarily specify a single interface.
*/
if (IN6_IS_ADDR_LINKLOCAL(&addr->sin6_addr) &&
ntohs(*(u_int16_t *)&addr->sin6_addr.s6_addr[2]) == ifp->if_index)
return (1);
TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
if (ifa->ifa_addr->sa_family != AF_INET6)
continue;
ia6 = ifatoia6(ifa);
/* Prefix check down below. */
if (ia6->ia6_flags & IN6_IFF_AUTOCONF)
continue;
if (IN6_ARE_MASKED_ADDR_EQUAL(&addr->sin6_addr,
&ia6->ia_addr.sin6_addr,
&ia6->ia_prefixmask.sin6_addr))
return (1);
}
/*
* Even if the address matches none of our addresses, it might be
* in the neighbor cache.
*/
rt = nd6_lookup(&addr->sin6_addr, 0, ifp, ifp->if_rdomain);
if (rt != NULL) {
rtfree(rt);
return (1);
}
return (0);
}
void
nd6_invalidate(struct rtentry *rt)
{
struct llinfo_nd6 *ln;
struct sockaddr_dl *sdl = satosdl(rt->rt_gateway);
mtx_enter(&nd6_mtx);
ln = (struct llinfo_nd6 *)rt->rt_llinfo;
if (ln == NULL) {
mtx_leave(&nd6_mtx);
return;
}
atomic_sub_int(&ln_hold_total, mq_purge(&ln->ln_mq));
sdl->sdl_alen = 0;
ln->ln_state = ND6_LLINFO_INCOMPLETE;
ln->ln_asked = 0;
mtx_leave(&nd6_mtx);
}
/*
* Free an nd6 llinfo entry.
*/
void
nd6_free(struct rtentry *rt, int i_am_router)
{
struct llinfo_nd6 *ln = (struct llinfo_nd6 *)rt->rt_llinfo;
struct in6_addr in6 = satosin6(rt_key(rt))->sin6_addr;
struct ifnet *ifp;
NET_ASSERT_LOCKED_EXCLUSIVE();
ifp = if_get(rt->rt_ifidx);
if (!i_am_router) {
if (ln->ln_router) {
/*
* rt6_flush must be called whether or not the neighbor
* is in the Default Router List.
* See a corresponding comment in nd6_na_input().
*/
rt6_flush(&in6, ifp);
}
}
KASSERT(!ISSET(rt->rt_flags, RTF_LOCAL));
nd6_invalidate(rt);
/*
* Detach the route from the routing tree and the list of neighbor
* caches, and disable the route entry not to be used in already
* cached routes.
*/
if (!ISSET(rt->rt_flags, RTF_STATIC|RTF_CACHED))
rtdeletemsg(rt, ifp, ifp->if_rdomain);
if_put(ifp);
}
/*
* Upper-layer reachability hint for Neighbor Unreachability Detection.
*
* XXX cost-effective methods?
*/
void
nd6_nud_hint(struct rtentry *rt)
{
struct llinfo_nd6 *ln;
struct ifnet *ifp;
NET_ASSERT_LOCKED_EXCLUSIVE();
ifp = if_get(rt->rt_ifidx);
if (ifp == NULL)
return;
if ((rt->rt_flags & RTF_GATEWAY) != 0 ||
(rt->rt_flags & RTF_LLINFO) == 0 ||
rt->rt_llinfo == NULL || rt->rt_gateway == NULL ||
rt->rt_gateway->sa_family != AF_LINK) {
/* This is not a host route. */
goto out;
}
ln = (struct llinfo_nd6 *)rt->rt_llinfo;
if (ln->ln_state < ND6_LLINFO_REACHABLE)
goto out;
/*
* if we get upper-layer reachability confirmation many times,
* it is possible we have false information.
*/
ln->ln_byhint++;
if (ln->ln_byhint > nd6_maxnudhint)
goto out;
ln->ln_state = ND6_LLINFO_REACHABLE;
if (!ND6_LLINFO_PERMANENT(ln))
nd6_llinfo_settimer(ln, ifp->if_nd->reachable);
out:
if_put(ifp);
}
void
nd6_rtrequest(struct ifnet *ifp, int req, struct rtentry *rt)
{
struct sockaddr *gate = rt->rt_gateway;
struct llinfo_nd6 *ln;
struct ifaddr *ifa;
struct in6_ifaddr *ifa6;
if (ISSET(rt->rt_flags, RTF_GATEWAY|RTF_MULTICAST|RTF_MPLS))
return;
if (nd6_need_cache(ifp) == 0 && (rt->rt_flags & RTF_HOST) == 0) {
/*
* This is probably an interface direct route for a link
* which does not need neighbor caches (e.g. fe80::%lo0/64).
* We do not need special treatment below for such a route.
* Moreover, the RTF_LLINFO flag which would be set below
* would annoy the ndp(8) command.
*/
return;
}
if (req == RTM_RESOLVE && nd6_need_cache(ifp) == 0) {
/*
* For routing daemons like ospf6d we allow neighbor discovery
* based on the cloning route only. This allows us to send
* packets directly into a network without having an address
* with matching prefix on the interface. If the cloning
* route is used for an 6to4 interface, we would mistakenly
* make a neighbor cache for the host route, and would see
* strange neighbor solicitation for the corresponding
* destination. In order to avoid confusion, we check if the
* interface is suitable for neighbor discovery, and stop the
* process if not. Additionally, we remove the LLINFO flag
* so that ndp(8) will not try to get the neighbor information
* of the destination.
*/
rt->rt_flags &= ~RTF_LLINFO;
return;
}
switch (req) {
case RTM_ADD:
if (rt->rt_flags & RTF_CLONING) {
rt->rt_expire = 0;
break;
}
if ((rt->rt_flags & RTF_LOCAL) && rt->rt_llinfo == NULL)
rt->rt_expire = 0;
/* FALLTHROUGH */
case RTM_RESOLVE:
if (gate->sa_family != AF_LINK ||
gate->sa_len < sizeof(struct sockaddr_dl)) {
log(LOG_DEBUG, "%s: bad gateway value: %s\n",
__func__, ifp->if_xname);
break;
}
satosdl(gate)->sdl_type = ifp->if_type;
satosdl(gate)->sdl_index = ifp->if_index;
/*
* Case 2: This route may come from cloning, or a manual route
* add with a LL address.
*/
ln = pool_get(&nd6_pool, PR_NOWAIT | PR_ZERO);
if (ln == NULL) {
log(LOG_DEBUG, "%s: pool get failed\n", __func__);
break;
}
mtx_enter(&nd6_mtx);
if (rt->rt_llinfo != NULL) {
/* we lost the race, another thread has entered it */
mtx_leave(&nd6_mtx);
pool_put(&nd6_pool, ln);
break;
}
nd6_inuse++;
mq_init(&ln->ln_mq, LN_HOLD_QUEUE, IPL_SOFTNET);
rt->rt_llinfo = (caddr_t)ln;
ln->ln_rt = rt;
rt->rt_flags |= RTF_LLINFO;
TAILQ_INSERT_HEAD(&nd6_list, ln, ln_list);
/* this is required for "ndp" command. - shin */
if (req == RTM_ADD) {
/*
* gate should have some valid AF_LINK entry,
* and ln expire should have some lifetime
* which is specified by ndp command.
*/
ln->ln_state = ND6_LLINFO_REACHABLE;
ln->ln_byhint = 0;
} else {
/*
* When req == RTM_RESOLVE, rt is created and
* initialized in rtrequest(), so rt_expire is 0.
*/
ln->ln_state = ND6_LLINFO_NOSTATE;
nd6_llinfo_settimer(ln, 0);
}
/*
* If we have too many cache entries, initiate immediate
* purging for some "less recently used" entries. Note that
* we cannot directly call nd6_free() here because it would
* cause re-entering rtable related routines triggering
* lock-order-reversal problems.
*/
if (ip6_neighborgcthresh >= 0 &&
nd6_inuse >= ip6_neighborgcthresh) {
int i;
for (i = 0; i < 10; i++) {
struct llinfo_nd6 *ln_end;
ln_end = TAILQ_LAST(&nd6_list, llinfo_nd6_head);
if (ln_end == ln)
break;
/* Move this entry to the head */
TAILQ_REMOVE(&nd6_list, ln_end, ln_list);
TAILQ_INSERT_HEAD(&nd6_list, ln_end, ln_list);
if (ND6_LLINFO_PERMANENT(ln_end))
continue;
if (ln_end->ln_state > ND6_LLINFO_INCOMPLETE)
ln_end->ln_state = ND6_LLINFO_STALE;
else
ln_end->ln_state = ND6_LLINFO_PURGE;
nd6_llinfo_settimer(ln_end, 0);
}
}
/*
* check if rt_key(rt) is one of my address assigned
* to the interface.
*/
ifa6 = in6ifa_ifpwithaddr(ifp,
&satosin6(rt_key(rt))->sin6_addr);
ifa = ifa6 ? &ifa6->ia_ifa : NULL;
if (ifa != NULL ||
(rt->rt_flags & RTF_ANNOUNCE)) {
ln->ln_state = ND6_LLINFO_REACHABLE;
ln->ln_byhint = 0;
rt->rt_expire = 0;
}
mtx_leave(&nd6_mtx);
/* join solicited node multicast for proxy ND */
if (ifa == NULL &&
(rt->rt_flags & RTF_ANNOUNCE) &&
(ifp->if_flags & IFF_MULTICAST)) {
struct in6_addr llsol;
int error;
llsol = satosin6(rt_key(rt))->sin6_addr;
llsol.s6_addr16[0] = htons(0xff02);
llsol.s6_addr16[1] = htons(ifp->if_index);
llsol.s6_addr32[1] = 0;
llsol.s6_addr32[2] = htonl(1);
llsol.s6_addr8[12] = 0xff;
KERNEL_LOCK();
if (in6_addmulti(&llsol, ifp, &error)) {
char addr[INET6_ADDRSTRLEN];
nd6log((LOG_ERR, "%s: failed to join "
"%s (errno=%d)\n", ifp->if_xname,
inet_ntop(AF_INET6, &llsol,
addr, sizeof(addr)),
error));
}
KERNEL_UNLOCK();
}
break;
case RTM_DELETE:
mtx_enter(&nd6_mtx);
ln = (struct llinfo_nd6 *)rt->rt_llinfo;
if (ln == NULL) {
/* we lost the race, another thread has removed it */
mtx_leave(&nd6_mtx);
break;
}
nd6_inuse--;
TAILQ_REMOVE(&nd6_list, ln, ln_list);
rt->rt_expire = 0;
rt->rt_llinfo = NULL;
rt->rt_flags &= ~RTF_LLINFO;
atomic_sub_int(&ln_hold_total, mq_purge(&ln->ln_mq));
mtx_leave(&nd6_mtx);
pool_put(&nd6_pool, ln);
/* leave from solicited node multicast for proxy ND */
if ((rt->rt_flags & RTF_ANNOUNCE) != 0 &&
(ifp->if_flags & IFF_MULTICAST) != 0) {
struct in6_addr llsol;
struct in6_multi *in6m;
llsol = satosin6(rt_key(rt))->sin6_addr;
llsol.s6_addr16[0] = htons(0xff02);
llsol.s6_addr16[1] = htons(ifp->if_index);
llsol.s6_addr32[1] = 0;
llsol.s6_addr32[2] = htonl(1);
llsol.s6_addr8[12] = 0xff;
KERNEL_LOCK();
IN6_LOOKUP_MULTI(llsol, ifp, in6m);
if (in6m)
in6_delmulti(in6m);
KERNEL_UNLOCK();
}
break;
case RTM_INVALIDATE:
if (!ISSET(rt->rt_flags, RTF_LOCAL))
nd6_invalidate(rt);
break;
}
}
int
nd6_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp)
{
struct in6_ndireq *ndi = (struct in6_ndireq *)data;
struct in6_nbrinfo *nbi = (struct in6_nbrinfo *)data;
struct rtentry *rt;
switch (cmd) {
case SIOCGIFINFO_IN6:
NET_LOCK_SHARED();
ndi->ndi = *ifp->if_nd;
NET_UNLOCK_SHARED();
return (0);
case SIOCGNBRINFO_IN6:
{
struct llinfo_nd6 *ln;
struct in6_addr nb_addr = nbi->addr; /* make local for safety */
time_t expire;
NET_LOCK_SHARED();
/*
* XXX: KAME specific hack for scoped addresses
* XXXX: for other scopes than link-local?
*/
if (IN6_IS_ADDR_LINKLOCAL(&nb_addr) ||
IN6_IS_ADDR_MC_LINKLOCAL(&nb_addr)) {
u_int16_t *idp = (u_int16_t *)&nb_addr.s6_addr[2];
if (*idp == 0)
*idp = htons(ifp->if_index);
}
rt = nd6_lookup(&nb_addr, 0, ifp, ifp->if_rdomain);
mtx_enter(&nd6_mtx);
if (rt == NULL ||
(ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) {
mtx_leave(&nd6_mtx);
rtfree(rt);
NET_UNLOCK_SHARED();
return (EINVAL);
}
expire = ln->ln_rt->rt_expire;
if (expire != 0) {
expire -= getuptime();
expire += gettime();
}
nbi->state = ln->ln_state;
nbi->asked = ln->ln_asked;
nbi->isrouter = ln->ln_router;
nbi->expire = expire;
mtx_leave(&nd6_mtx);
rtfree(rt);
NET_UNLOCK_SHARED();
return (0);
}
}
return (0);
}
/*
* Create neighbor cache entry and cache link-layer address,
* on reception of inbound ND6 packets. (RS/RA/NS/redirect)
*
* type - ICMP6 type
* code - type dependent information
*/
void
nd6_cache_lladdr(struct ifnet *ifp, const struct in6_addr *from, char *lladdr,
int lladdrlen, int type, int code, int i_am_router)
{
struct rtentry *rt;
struct llinfo_nd6 *ln;
int is_newentry;
struct sockaddr_dl *sdl;
int do_update;
int olladdr;
int llchange;
int newstate = 0;
NET_ASSERT_LOCKED_EXCLUSIVE();
if (!ifp)
panic("%s: ifp == NULL", __func__);
if (!from)
panic("%s: from == NULL", __func__);
/* nothing must be updated for unspecified address */
if (IN6_IS_ADDR_UNSPECIFIED(from))
return;
/*
* Validation about ifp->if_addrlen and lladdrlen must be done in
* the caller.
*
* XXX If the link does not have link-layer address, what should
* we do? (ifp->if_addrlen == 0)
* Spec says nothing in sections for RA, RS and NA. There's small
* description on it in NS section (RFC 2461 7.2.3).
*/
rt = nd6_lookup(from, 0, ifp, ifp->if_rdomain);
if (rt == NULL) {
rt = nd6_lookup(from, 1, ifp, ifp->if_rdomain);
is_newentry = 1;
} else {
/* do not overwrite local or static entry */
if (ISSET(rt->rt_flags, RTF_STATIC|RTF_LOCAL)) {
rtfree(rt);
return;
}
is_newentry = 0;
}
if (!rt)
return;
if ((rt->rt_flags & (RTF_GATEWAY | RTF_LLINFO)) != RTF_LLINFO) {
fail:
nd6_free(rt, i_am_router);
rtfree(rt);
return;
}
ln = (struct llinfo_nd6 *)rt->rt_llinfo;
if (ln == NULL)
goto fail;
if (rt->rt_gateway == NULL)
goto fail;
if (rt->rt_gateway->sa_family != AF_LINK)
goto fail;
sdl = satosdl(rt->rt_gateway);
olladdr = (sdl->sdl_alen) ? 1 : 0;
if (olladdr && lladdr) {
if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
llchange = 1;
else
llchange = 0;
} else
llchange = 0;
/*
* newentry olladdr lladdr llchange (*=record)
* 0 n n -- (1)
* 0 y n -- (2)
* 0 n y -- (3) * STALE
* 0 y y n (4) *
* 0 y y y (5) * STALE
* 1 -- n -- (6) NOSTATE(= PASSIVE)
* 1 -- y -- (7) * STALE
*/
if (llchange) {
char addr[INET6_ADDRSTRLEN];
log(LOG_INFO, "ndp info overwritten for %s by %s on %s\n",
inet_ntop(AF_INET6, from, addr, sizeof(addr)),
ether_sprintf(lladdr), ifp->if_xname);
}
if (lladdr) { /* (3-5) and (7) */
/*
* Record source link-layer address
* XXX is it dependent to ifp->if_type?
*/
sdl->sdl_alen = ifp->if_addrlen;
bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
}
if (!is_newentry) {
if ((!olladdr && lladdr) || /* (3) */
(olladdr && lladdr && llchange)) { /* (5) */
do_update = 1;
newstate = ND6_LLINFO_STALE;
} else /* (1-2,4) */
do_update = 0;
} else {
do_update = 1;
if (!lladdr) /* (6) */
newstate = ND6_LLINFO_NOSTATE;
else /* (7) */
newstate = ND6_LLINFO_STALE;
}
if (do_update) {
/*
* Update the state of the neighbor cache.
*/
ln->ln_state = newstate;
if (ln->ln_state == ND6_LLINFO_STALE) {
/*
* Since nd6_resolve() in ifp->if_output() will cause
* state transition to DELAY and reset the timer,
* we must set the timer now, although it is actually
* meaningless.
*/
nd6_llinfo_settimer(ln, nd6_gctimer);
if_output_mq(ifp, &ln->ln_mq, &ln_hold_total,
rt_key(rt), rt);
} else if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
/* probe right away */
nd6_llinfo_settimer(ln, 0);
}
}
/*
* ICMP6 type dependent behavior.
*
* NS: clear IsRouter if new entry
* RS: clear IsRouter
* RA: set IsRouter if there's lladdr
* redir: clear IsRouter if new entry
*
* RA case, (1):
* The spec says that we must set IsRouter in the following cases:
* - If lladdr exist, set IsRouter. This means (1-5).
* - If it is old entry (!newentry), set IsRouter. This means (7).
* So, based on the spec, in (1-5) and (7) cases we must set IsRouter.
* A question arises for (1) case. (1) case has no lladdr in the
* neighbor cache, this is similar to (6).
* This case is rare but we figured that we MUST NOT set IsRouter.
*
* newentry olladdr lladdr llchange NS RS RA redir
* D R
* 0 n n -- (1) c ? s
* 0 y n -- (2) c s s
* 0 n y -- (3) c s s
* 0 y y n (4) c s s
* 0 y y y (5) c s s
* 1 -- n -- (6) c c c s
* 1 -- y -- (7) c c s c s
*
* (c=clear s=set)
*/
switch (type & 0xff) {
case ND_NEIGHBOR_SOLICIT:
/*
* New entry must have is_router flag cleared.
*/
if (is_newentry) /* (6-7) */
ln->ln_router = 0;
break;
case ND_REDIRECT:
/*
* If the icmp is a redirect to a better router, always set the
* is_router flag. Otherwise, if the entry is newly created,
* clear the flag. [RFC 2461, sec 8.3]
*/
if (code == ND_REDIRECT_ROUTER)
ln->ln_router = 1;
else if (is_newentry) /* (6-7) */
ln->ln_router = 0;
break;
case ND_ROUTER_SOLICIT:
/*
* is_router flag must always be cleared.
*/
ln->ln_router = 0;
break;
case ND_ROUTER_ADVERT:
/*
* Mark an entry with lladdr as a router.
*/
if ((!is_newentry && (olladdr || lladdr)) || /* (2-5) */
(is_newentry && lladdr)) { /* (7) */
ln->ln_router = 1;
}
break;
}
rtfree(rt);
}
void
nd6_slowtimo(void *ignored_arg)
{
struct nd_ifinfo *nd6if;
struct ifnet *ifp;
NET_LOCK();
timeout_add_sec(&nd6_slowtimo_ch, ND6_SLOWTIMER_INTERVAL);
TAILQ_FOREACH(ifp, &ifnetlist, if_list) {
nd6if = ifp->if_nd;
if ((nd6if->recalctm -= ND6_SLOWTIMER_INTERVAL) <= 0) {
/*
* Since reachable time rarely changes by router
* advertisements, we SHOULD insure that a new random
* value gets recomputed at least once every few hours.
* (RFC 2461, 6.3.4)
*/
nd6if->recalctm = ND6_RECALC_REACHTM_INTERVAL;
nd6if->reachable = ND_COMPUTE_RTIME(REACHABLE_TIME);
}
}
NET_UNLOCK();
}
int
nd6_resolve(struct ifnet *ifp, struct rtentry *rt0, struct mbuf *m,
struct sockaddr *dst, u_char *desten)
{
struct sockaddr_dl *sdl;
struct rtentry *rt;
struct llinfo_nd6 *ln;
struct in6_addr saddr6;
time_t uptime;
int solicit = 0;
if (m->m_flags & M_MCAST) {
ETHER_MAP_IPV6_MULTICAST(&satosin6(dst)->sin6_addr, desten);
return (0);
}
uptime = getuptime();
rt = rt_getll(rt0);
if (ISSET(rt->rt_flags, RTF_REJECT) &&
(rt->rt_expire == 0 || rt->rt_expire > uptime)) {
m_freem(m);
return (rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
}
/*
* Address resolution or Neighbor Unreachability Detection
* for the next hop.
* At this point, the destination of the packet must be a unicast
* or an anycast address(i.e. not a multicast).
*/
if (!ISSET(rt->rt_flags, RTF_LLINFO)) {
char addr[INET6_ADDRSTRLEN];
log(LOG_DEBUG, "%s: %s: route contains no ND information\n",
__func__, inet_ntop(AF_INET6,
&satosin6(rt_key(rt))->sin6_addr, addr, sizeof(addr)));
goto bad;
}
if (rt->rt_gateway->sa_family != AF_LINK) {
printf("%s: something odd happens\n", __func__);
goto bad;
}
mtx_enter(&nd6_mtx);
ln = (struct llinfo_nd6 *)rt->rt_llinfo;
if (ln == NULL) {
mtx_leave(&nd6_mtx);
goto bad;
}
/*
* Move this entry to the head of the queue so that it is less likely
* for this entry to be a target of forced garbage collection (see
* nd6_rtrequest()).
*/
TAILQ_REMOVE(&nd6_list, ln, ln_list);
TAILQ_INSERT_HEAD(&nd6_list, ln, ln_list);
/*
* The first time we send a packet to a neighbor whose entry is
* STALE, we have to change the state to DELAY and set a timer to
* expire in DELAY_FIRST_PROBE_TIME seconds to ensure we do
* neighbor unreachability detection on expiration.
* (RFC 2461 7.3.3)
*/
if (ln->ln_state == ND6_LLINFO_STALE) {
ln->ln_asked = 0;
ln->ln_state = ND6_LLINFO_DELAY;
nd6_llinfo_settimer(ln, nd6_delay);
}
/*
* If the neighbor cache entry has a state other than INCOMPLETE
* (i.e. its link-layer address is already resolved), just
* send the packet.
*/
if (ln->ln_state > ND6_LLINFO_INCOMPLETE) {
mtx_leave(&nd6_mtx);
sdl = satosdl(rt->rt_gateway);
if (sdl->sdl_alen != ETHER_ADDR_LEN) {
char addr[INET6_ADDRSTRLEN];
log(LOG_DEBUG, "%s: %s: incorrect nd6 information\n",
__func__,
inet_ntop(AF_INET6, &satosin6(dst)->sin6_addr,
addr, sizeof(addr)));
goto bad;
}
bcopy(LLADDR(sdl), desten, sdl->sdl_alen);
return (0);
}
/*
* There is a neighbor cache entry, but no ethernet address
* response yet. Insert mbuf in hold queue if below limit.
* If above the limit free the queue without queuing the new packet.
*/
if (ln->ln_state == ND6_LLINFO_NOSTATE)
ln->ln_state = ND6_LLINFO_INCOMPLETE;
/* source address of prompting packet is needed by nd6_ns_output() */
if (m->m_len >= sizeof(struct ip6_hdr)) {
memcpy(&ln->ln_saddr6, &mtod(m, struct ip6_hdr *)->ip6_src,
sizeof(ln->ln_saddr6));
}
if (atomic_inc_int_nv(&ln_hold_total) <= LN_HOLD_TOTAL) {
if (mq_push(&ln->ln_mq, m) != 0)
atomic_dec_int(&ln_hold_total);
} else {
atomic_sub_int(&ln_hold_total, mq_purge(&ln->ln_mq) + 1);
m_freem(m);
}
/*
* If there has been no NS for the neighbor after entering the
* INCOMPLETE state, send the first solicitation.
*/
if (!ND6_LLINFO_PERMANENT(ln) && ln->ln_asked == 0) {
ln->ln_asked++;
nd6_llinfo_settimer(ln, RETRANS_TIMER / 1000);
saddr6 = ln->ln_saddr6;
solicit = 1;
}
mtx_leave(&nd6_mtx);
if (solicit)
nd6_ns_output(ifp, NULL, &satosin6(dst)->sin6_addr, &saddr6, 0);
return (EAGAIN);
bad:
m_freem(m);
return (EINVAL);
}
int
nd6_need_cache(struct ifnet *ifp)
{
/*
* RFC2893 says:
* - unidirectional tunnels needs no ND
*/
switch (ifp->if_type) {
case IFT_ETHER:
case IFT_IEEE80211:
case IFT_CARP:
return (1);
default:
return (0);
}
}
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