/*
* Input a Neighbor Solicitation Message.
*
* Based on RFC 2461
* Based on RFC 2462 (duplicate address detection)
*/
void
nd6_ns_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_neighbor_solicit *nd_ns;
struct in6_addr saddr6 = ip6->ip6_src;
struct in6_addr daddr6 = ip6->ip6_dst;
struct in6_addr taddr6;
struct in6_addr myaddr6;
char *lladdr = NULL;
struct ifaddr *ifa = NULL;
int lladdrlen = 0;
int anycast = 0, proxy = 0, tentative = 0;
int tlladdr;
int rflag;
union nd_opts ndopts;
struct sockaddr_dl proxydl;
char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
rflag = (V_ip6_forwarding) ? ND_NA_FLAG_ROUTER : 0;
if (ND_IFINFO(ifp)->flags & ND6_IFF_ACCEPT_RTADV && V_ip6_norbit_raif)
rflag = 0;
#ifndef PULLDOWN_TEST
IP6_EXTHDR_CHECK(m, off, icmp6len,);
nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
#else
IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
if (nd_ns == NULL) {
ICMP6STAT_INC(icp6s_tooshort);
return;
}
#endif
ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
taddr6 = nd_ns->nd_ns_target;
if (in6_setscope(&taddr6, ifp, NULL) != 0)
goto bad;
if (ip6->ip6_hlim != 255) {
nd6log((LOG_ERR,
"nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
ip6->ip6_hlim, ip6_sprintf(ip6bufs, &ip6->ip6_src),
ip6_sprintf(ip6bufd, &ip6->ip6_dst), if_name(ifp)));
goto bad;
}
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
/* dst has to be a solicited node multicast address. */
if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
/* don't check ifindex portion */
daddr6.s6_addr32[1] == 0 &&
daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
daddr6.s6_addr8[12] == 0xff) {
; /* good */
} else {
nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
"(wrong ip6 dst)\n"));
goto bad;
}
} else if (!V_nd6_onlink_ns_rfc4861) {
struct sockaddr_in6 src_sa6;
/*
* According to recent IETF discussions, it is not a good idea
* to accept a NS from an address which would not be deemed
* to be a neighbor otherwise. This point is expected to be
* clarified in future revisions of the specification.
*/
bzero(&src_sa6, sizeof(src_sa6));
src_sa6.sin6_family = AF_INET6;
src_sa6.sin6_len = sizeof(src_sa6);
src_sa6.sin6_addr = saddr6;
if (nd6_is_addr_neighbor(&src_sa6, ifp) == 0) {
nd6log((LOG_INFO, "nd6_ns_input: "
"NS packet from non-neighbor\n"));
goto bad;
}
}
if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
goto bad;
}
icmp6len -= sizeof(*nd_ns);
nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
if (nd6_options(&ndopts) < 0) {
nd6log((LOG_INFO,
"nd6_ns_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 (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
"(link-layer address option)\n"));
goto bad;
}
/*
* Attaching target link-layer address to the NA?
* (RFC 2461 7.2.4)
*
* NS IP dst is unicast/anycast MUST NOT add
* NS IP dst is solicited-node multicast MUST add
*
* In implementation, we add target link-layer address by default.
* We do not add one in MUST NOT cases.
*/
if (!IN6_IS_ADDR_MULTICAST(&daddr6))
tlladdr = 0;
else
tlladdr = 1;
/*
* Target address (taddr6) must be either:
* (1) Valid unicast/anycast address for my receiving interface,
* (2) Unicast address for which I'm offering proxy service, or
* (3) "tentative" address on which DAD is being performed.
*/
/* (1) and (3) check. */
if (ifp->if_carp)
ifa = (*carp_iamatch6_p)(ifp, &taddr6);
else
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
/* (2) check. */
if (ifa == NULL) {
struct route_in6 ro;
int need_proxy;
bzero(&ro, sizeof(ro));
ro.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
ro.ro_dst.sin6_family = AF_INET6;
ro.ro_dst.sin6_addr = taddr6;
/* Always use the default FIB. */
#ifdef RADIX_MPATH
rtalloc_mpath_fib((struct route *)&ro, RTF_ANNOUNCE,
RT_DEFAULT_FIB);
#else
in6_rtalloc(&ro, RT_DEFAULT_FIB);
#endif
need_proxy = (ro.ro_rt &&
(ro.ro_rt->rt_flags & RTF_ANNOUNCE) != 0 &&
ro.ro_rt->rt_gateway->sa_family == AF_LINK);
if (ro.ro_rt != NULL) {
if (need_proxy)
proxydl = *SDL(ro.ro_rt->rt_gateway);
RTFREE(ro.ro_rt);
}
if (need_proxy) {
/*
* proxy NDP for single entry
*/
ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
if (ifa)
proxy = 1;
}
}
if (ifa == NULL) {
/*
* We've got an NS packet, and we don't have that adddress
* assigned for us. We MUST silently ignore it.
* See RFC2461 7.2.3.
*/
goto freeit;
}
myaddr6 = *IFA_IN6(ifa);
anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
goto freeit;
if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
"(if %d, NS packet %d)\n",
ip6_sprintf(ip6bufs, &taddr6),
ifp->if_addrlen, lladdrlen - 2));
goto bad;
}
if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
ip6_sprintf(ip6bufs, &saddr6)));
goto freeit;
}
/*
* We have neighbor solicitation packet, with target address equals to
* one of my tentative address.
*
* src addr how to process?
* --- ---
* multicast of course, invalid (rejected in ip6_input)
* unicast somebody is doing address resolution -> ignore
* unspec dup address detection
*
* The processing is defined in RFC 2462.
*/
if (tentative) {
/*
* If source address is unspecified address, it is for
* duplicate address detection.
*
* If not, the packet is for addess resolution;
* silently ignore it.
*/
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
nd6_dad_ns_input(ifa, ndopts.nd_opts_nonce);
goto freeit;
}
/*
* If the source address is unspecified address, entries must not
* be created or updated.
* It looks that sender is performing DAD. Output NA toward
* all-node multicast address, to tell the sender that I'm using
* the address.
* S bit ("solicited") must be zero.
*/
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
struct in6_addr in6_all;
in6_all = in6addr_linklocal_allnodes;
if (in6_setscope(&in6_all, ifp, NULL) != 0)
goto bad;
nd6_na_output_fib(ifp, &in6_all, &taddr6,
((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
rflag, tlladdr, proxy ? (struct sockaddr *)&proxydl : NULL,
M_GETFIB(m));
goto freeit;
}
nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen,
ND_NEIGHBOR_SOLICIT, 0);
nd6_na_output_fib(ifp, &saddr6, &taddr6,
((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
rflag | ND_NA_FLAG_SOLICITED, tlladdr,
proxy ? (struct sockaddr *)&proxydl : NULL, M_GETFIB(m));
freeit:
if (ifa != NULL)
ifa_free(ifa);
m_freem(m);
return;
bad:
nd6log((LOG_ERR, "nd6_ns_input: src=%s\n",
ip6_sprintf(ip6bufs, &saddr6)));
nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n",
ip6_sprintf(ip6bufs, &daddr6)));
nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n",
ip6_sprintf(ip6bufs, &taddr6)));
ICMP6STAT_INC(icp6s_badns);
if (ifa != NULL)
ifa_free(ifa);
m_freem(m);
}
/*
* Input a Neighbor Solicitation Message.
*
* Based on RFC 2461
* Based on RFC 2462 (duplicate address detection)
*/
void
nd6_ns_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_neighbor_solicit *nd_ns;
struct in6_addr saddr6 = ip6->ip6_src;
struct in6_addr daddr6 = ip6->ip6_dst;
struct in6_addr taddr6;
struct in6_addr myaddr6;
char *lladdr = NULL;
struct ifaddr *ifa;
int lladdrlen = 0;
int anycast = 0, proxy = 0, tentative = 0;
int router = ip6_forwarding;
int tlladdr;
union nd_opts ndopts;
const struct sockaddr_dl *proxydl = NULL;
IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
if (nd_ns == NULL) {
ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
return;
}
ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
taddr6 = nd_ns->nd_ns_target;
if (in6_setscope(&taddr6, ifp, NULL) != 0)
goto bad;
if (ip6->ip6_hlim != 255) {
nd6log((LOG_ERR,
"nd6_ns_input: invalid hlim (%d) from %s to %s on %s\n",
ip6->ip6_hlim, ip6_sprintf(&ip6->ip6_src),
ip6_sprintf(&ip6->ip6_dst), if_name(ifp)));
goto bad;
}
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
/* dst has to be a solicited node multicast address. */
/* don't check ifindex portion */
if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL &&
daddr6.s6_addr32[1] == 0 &&
daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE &&
daddr6.s6_addr8[12] == 0xff) {
; /* good */
} else {
nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
"(wrong ip6 dst)\n"));
goto bad;
}
} else {
struct sockaddr_in6 ssin6;
/*
* Make sure the source address is from a neighbor's address.
*/
sockaddr_in6_init(&ssin6, &saddr6, 0, 0, 0);
if (nd6_is_addr_neighbor(&ssin6, ifp) == 0) {
nd6log((LOG_INFO, "nd6_ns_input: "
"NS packet from non-neighbor\n"));
goto bad;
}
}
if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
nd6log((LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n"));
goto bad;
}
icmp6len -= sizeof(*nd_ns);
nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
if (nd6_options(&ndopts) < 0) {
nd6log((LOG_INFO,
"nd6_ns_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 (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
nd6log((LOG_INFO, "nd6_ns_input: bad DAD packet "
"(link-layer address option)\n"));
goto bad;
}
/*
* Attaching target link-layer address to the NA?
* (RFC 2461 7.2.4)
*
* NS IP dst is multicast MUST add
* Otherwise MAY be omitted
*
* In this implementation, we omit the target link-layer address
* in the "MAY" case.
*/
#if 0 /* too much! */
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
tlladdr = 0;
else
#endif
if (!IN6_IS_ADDR_MULTICAST(&daddr6))
tlladdr = 0;
else
tlladdr = 1;
/*
* Target address (taddr6) must be either:
* (1) Valid unicast/anycast address for my receiving interface,
* (2) Unicast address for which I'm offering proxy service, or
* (3) "tentative" address on which DAD is being performed.
*/
/* (1) and (3) check. */
#if NCARP > 0
if (ifp->if_carp && ifp->if_type != IFT_CARP)
ifa = carp_iamatch6(ifp->if_carp, &taddr6);
else
ifa = NULL;
if (!ifa)
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#else
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#endif
/* (2) check. */
if (ifa == NULL) {
struct rtentry *rt;
struct sockaddr_in6 tsin6;
sockaddr_in6_init(&tsin6, &taddr6, 0, 0, 0);
rt = rtalloc1((struct sockaddr *)&tsin6, 0);
if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
rt->rt_gateway->sa_family == AF_LINK) {
/*
* proxy NDP for single entry
*/
ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
if (ifa) {
proxy = 1;
proxydl = satocsdl(rt->rt_gateway);
router = 0; /* XXX */
}
}
if (rt)
rtfree(rt);
}
if (ifa == NULL) {
/*
* We've got an NS packet, and we don't have that address
* assigned for us. We MUST silently ignore it.
* See RFC2461 7.2.3.
*/
goto freeit;
}
myaddr6 = *IFA_IN6(ifa);
anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
goto freeit;
if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
nd6log((LOG_INFO, "nd6_ns_input: lladdrlen mismatch for %s "
"(if %d, NS packet %d)\n",
ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2));
goto bad;
}
if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
nd6log((LOG_INFO, "nd6_ns_input: duplicate IP6 address %s\n",
ip6_sprintf(&saddr6)));
goto freeit;
}
/*
* We have neighbor solicitation packet, with target address equals to
* one of my tentative address.
*
* src addr how to process?
* --- ---
* multicast of course, invalid (rejected in ip6_input)
* unicast somebody is doing address resolution -> ignore
* unspec dup address detection
*
* The processing is defined in RFC 2462.
*/
if (tentative) {
/*
* If source address is unspecified address, it is for
* duplicate address detection.
*
* If not, the packet is for addess resolution;
* silently ignore it.
*/
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
nd6_dad_ns_input(ifa);
goto freeit;
}
/*
* If the source address is unspecified address, entries must not
* be created or updated.
* It looks that sender is performing DAD. Output NA toward
* all-node multicast address, to tell the sender that I'm using
* the address.
* S bit ("solicited") must be zero.
*/
if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
struct in6_addr in6_all;
in6_all = in6addr_linklocal_allnodes;
if (in6_setscope(&in6_all, ifp, NULL) != 0)
goto bad;
nd6_na_output(ifp, &in6_all, &taddr6,
((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
(ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
tlladdr, (const struct sockaddr *)proxydl);
goto freeit;
}
nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
nd6_na_output(ifp, &saddr6, &taddr6,
((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
(router ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
tlladdr, (const struct sockaddr *)proxydl);
freeit:
m_freem(m);
return;
bad:
nd6log((LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6)));
nd6log((LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6)));
nd6log((LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6)));
ICMP6_STATINC(ICMP6_STAT_BADNS);
m_freem(m);
}
ER
nd6_output (T_IFNET *ifp, T_NET_BUF *output, T_IN6_ADDR *dst, T_LLINFO_ND6 *ln, TMO tmout)
{
ER error = E_OK;
SYSTIM now;
/*
* あて先アドレスがマルチキャストか、近隣キャッシュが
* 不要の場合は直ちに送信する。
*/
if (!(IN6_IS_ADDR_MULTICAST(dst) || !IF_IN6_NEED_CACHE(ifp))) {
if (ln == NULL) {
/* 近隣キャッシュが未定義の場合 */
if (nd6_is_addr_neighbor(ifp, dst)) {
/*
* 指定されたアドレスのノードが同一リンクにある時は、
* 近隣キャッシュを探索し、未定義の場合は登録する。
*/
ln = nd6_lookup(dst, true);
}
else {
error = E_CLS;
goto err_ret;
}
}
/*
* 近隣キャッシュの状態が、データリンク層のアドレスが分かっていても、
* 到達可能性が確認されていないときは、到達不能通知を開始する。
*/
if (ln->state == ND6_LLINFO_STALE) {
syscall(get_tim(&now));
ln->expire = now + ND6_DELAY_TIME;
ln->asked = 0;
ln->state = ND6_LLINFO_DELAY;
}
/*
* 近隣キャッシュの状態が、データリンク層のアドレス未解決の場合は
* 近隣探索を行う。
*/
if (ln->state <= ND6_LLINFO_INCOMPLETE) {
/* タイムアウトの指定がポーリングならタイムアウトで終了する。*/
if (tmout == TMO_POL) {
error = E_TMOUT;
goto err_ret;
}
if (ln->state == ND6_LLINFO_NO_STATE)
ln->state = ND6_LLINFO_INCOMPLETE;
/* すでに、未解決のネットワークバッファがあれば、開放する。*/
if (ln->hold != NULL) {
syscall(rel_net_buf(ln->hold));
}
/*
* 送信をペンディングする。
* IF でネットワークバッファを開放しないフラグが設定されているときは、
* 送信をペンディングしない。
*/
if ((output->flags & NB_FLG_NOREL_IFOUT) == 0) {
ln->hold = output;
/* タイムアウトの設定 */
if (tmout == TMO_FEVR)
ln->tmout = tmout;
else {
syscall(get_tim(&now));
ln->tmout = now + tmout;
}
}
else {
output->flags &= ~NB_FLG_NOREL_IFOUT;
syscall(get_tim(&now));
ln->tmout = now + tmout;
}
if (ln->expire) {
if (ln->asked < ND6_MAX_MCAST_QUERY) {
syscall(get_tim(&now));
if ((int32_t)(ln->expire - now) < 0) {
/* ln->expire < now */
ln->expire += ND6_RETRANS_TIME; /* 近隣探索送信間隔 */
ln->asked ++;
nd6_ns_output(ifp, &in6_addr_unspecified, dst, ln, false);
}
}
}
return error;
}
}
/*
* 重複が検出されたインタフェースには出力しない。
*/
if ((ifp->flags & ND6_IFF_IFDISABLED) != 0) {
return E_OK;
}
IF_SET_PROTO(output, IF_PROTO_IPV6);
error = IF_OUTPUT(output, dst, ln ? & ln->ifaddr : NULL, tmout);
return error;
err_ret:
syscall(rel_net_buf(output));
return error;
}
void
ip6_forward(struct mbuf *m, int srcrt)
{
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
const struct sockaddr_in6 *dst;
struct rtentry *rt;
int error = 0, type = 0, code = 0;
struct mbuf *mcopy = NULL;
struct ifnet *origifp; /* maybe unnecessary */
uint32_t inzone, outzone;
struct in6_addr src_in6, dst_in6;
#ifdef IPSEC
int needipsec = 0;
struct secpolicy *sp = NULL;
#endif
/*
* Clear any in-bound checksum flags for this packet.
*/
m->m_pkthdr.csum_flags = 0;
/*
* Do not forward packets to multicast destination (should be handled
* by ip6_mforward().
* Do not forward packets with unspecified source. It was discussed
* in July 2000, on ipngwg mailing list.
*/
if ((m->m_flags & (M_BCAST|M_MCAST)) != 0 ||
IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
ip6_cantforward(ip6, m->m_pkthdr.rcvif, NULL,
((m->m_flags & (M_BCAST|M_MCAST)) != 0) ? "bcast/mcast" :
IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ? "mcast/dst" :
"unspec/src");
m_freem(m);
return;
}
if (ip6->ip6_hlim <= IPV6_HLIMDEC) {
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_discard) */
icmp6_error(m, ICMP6_TIME_EXCEEDED,
ICMP6_TIME_EXCEED_TRANSIT, 0);
return;
}
ip6->ip6_hlim -= IPV6_HLIMDEC;
/*
* Save at most ICMPV6_PLD_MAXLEN (= the min IPv6 MTU -
* size of IPv6 + ICMPv6 headers) bytes of the packet in case
* we need to generate an ICMP6 message to the src.
* Thanks to M_EXT, in most cases copy will not occur.
*
* It is important to save it before IPsec processing as IPsec
* processing may modify the mbuf.
*/
mcopy = m_copy(m, 0, imin(m->m_pkthdr.len, ICMPV6_PLD_MAXLEN));
#ifdef IPSEC
if (ipsec_used) {
/* Check the security policy (SP) for the packet */
sp = ipsec6_check_policy(m, NULL, 0, &needipsec, &error);
if (error != 0) {
/*
* Hack: -EINVAL is used to signal that a packet
* should be silently discarded. This is typically
* because we asked key management for an SA and
* it was delayed (e.g. kicked up to IKE).
*/
if (error == -EINVAL)
error = 0;
goto freecopy;
}
}
#endif /* IPSEC */
if (srcrt) {
union {
struct sockaddr dst;
struct sockaddr_in6 dst6;
} u;
sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0);
if ((rt = rtcache_lookup(&ip6_forward_rt, &u.dst)) == NULL) {
IP6_STATINC(IP6_STAT_NOROUTE);
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */
if (mcopy) {
icmp6_error(mcopy, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_NOROUTE, 0);
}
m_freem(m);
return;
}
} else if ((rt = rtcache_validate(&ip6_forward_rt)) == NULL &&
(rt = rtcache_update(&ip6_forward_rt, 1)) == NULL) {
/*
* rtcache_getdst(ip6_forward_rt)->sin6_addr was equal to
* ip6->ip6_dst
*/
IP6_STATINC(IP6_STAT_NOROUTE);
/* XXX in6_ifstat_inc(rt->rt_ifp, ifs6_in_noroute) */
if (mcopy) {
icmp6_error(mcopy, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_NOROUTE, 0);
}
m_freem(m);
return;
}
dst = satocsin6(rtcache_getdst(&ip6_forward_rt));
/*
* Source scope check: if a packet can't be delivered to its
* destination for the reason that the destination is beyond the scope
* of the source address, discard the packet and return an icmp6
* destination unreachable error with Code 2 (beyond scope of source
* address). We use a local copy of ip6_src, since in6_setscope()
* will possibly modify its first argument.
* [draft-ietf-ipngwg-icmp-v3-07, Section 3.1]
*/
src_in6 = ip6->ip6_src;
inzone = outzone = ~0;
if (in6_setscope(&src_in6, rt->rt_ifp, &outzone) != 0 ||
in6_setscope(&src_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
inzone != outzone) {
ip6_cantforward(ip6, m->m_pkthdr.rcvif, rt->rt_ifp,
"src[%s] inzone %d outzone %d",
in6_getscopename(&ip6->ip6_src), inzone, outzone);
if (mcopy)
icmp6_error(mcopy, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
m_freem(m);
return;
}
#ifdef IPSEC
/*
* If we need to encapsulate the packet, do it here
* ipsec6_proces_packet will send the packet using ip6_output
*/
if (needipsec) {
int s = splsoftnet();
error = ipsec6_process_packet(m, sp->req);
splx(s);
if (mcopy)
goto freecopy;
}
#endif
/*
* Destination scope check: if a packet is going to break the scope
* zone of packet's destination address, discard it. This case should
* usually be prevented by appropriately-configured routing table, but
* we need an explicit check because we may mistakenly forward the
* packet to a different zone by (e.g.) a default route.
*/
dst_in6 = ip6->ip6_dst;
inzone = outzone = ~0;
if (in6_setscope(&dst_in6, m->m_pkthdr.rcvif, &inzone) != 0 ||
in6_setscope(&dst_in6, rt->rt_ifp, &outzone) != 0 ||
inzone != outzone) {
ip6_cantforward(ip6, m->m_pkthdr.rcvif, rt->rt_ifp,
"dst[%s] inzone %d outzone %d",
in6_getscopename(&ip6->ip6_dst), inzone, outzone);
if (mcopy)
icmp6_error(mcopy, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_BEYONDSCOPE, 0);
m_freem(m);
return;
}
if (m->m_pkthdr.len > IN6_LINKMTU(rt->rt_ifp)) {
in6_ifstat_inc(rt->rt_ifp, ifs6_in_toobig);
if (mcopy) {
u_long mtu;
mtu = IN6_LINKMTU(rt->rt_ifp);
icmp6_error(mcopy, ICMP6_PACKET_TOO_BIG, 0, mtu);
}
m_freem(m);
return;
}
if (rt->rt_flags & RTF_GATEWAY)
dst = (struct sockaddr_in6 *)rt->rt_gateway;
/*
* If we are to forward the packet using the same interface
* as one we got the packet from, perhaps we should send a redirect
* to sender to shortcut a hop.
* Only send redirect if source is sending directly to us,
* and if packet was not source routed (or has any options).
* Also, don't send redirect if forwarding using a route
* modified by a redirect.
*/
if (rt->rt_ifp == m->m_pkthdr.rcvif && !srcrt && ip6_sendredirects &&
(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0) {
if ((rt->rt_ifp->if_flags & IFF_POINTOPOINT) &&
nd6_is_addr_neighbor(
satocsin6(rtcache_getdst(&ip6_forward_rt)),
rt->rt_ifp)) {
/*
* If the incoming interface is equal to the outgoing
* one, the link attached to the interface is
* point-to-point, and the IPv6 destination is
* regarded as on-link on the link, then it will be
* highly probable that the destination address does
* not exist on the link and that the packet is going
* to loop. Thus, we immediately drop the packet and
* send an ICMPv6 error message.
* For other routing loops, we dare to let the packet
* go to the loop, so that a remote diagnosing host
* can detect the loop by traceroute.
* type/code is based on suggestion by Rich Draves.
* not sure if it is the best pick.
*/
icmp6_error(mcopy, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_ADDR, 0);
m_freem(m);
return;
}
type = ND_REDIRECT;
}
/*
* Fake scoped addresses. Note that even link-local source or
* destinaion can appear, if the originating node just sends the
* packet to us (without address resolution for the destination).
* Since both icmp6_error and icmp6_redirect_output fill the embedded
* link identifiers, we can do this stuff after making a copy for
* returning an error.
*/
if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) != 0) {
/*
* See corresponding comments in ip6_output.
* XXX: but is it possible that ip6_forward() sends a packet
* to a loopback interface? I don't think so, and thus
* I bark here. ([email protected])
* XXX: it is common to route invalid packets to loopback.
* also, the codepath will be visited on use of ::1 in
* rthdr. (itojun)
*/
#if 1
if (0)
#else
if ((rt->rt_flags & (RTF_BLACKHOLE|RTF_REJECT)) == 0)
#endif
{
printf("ip6_forward: outgoing interface is loopback. "
"src %s, dst %s, nxt %d, rcvif %s, outif %s\n",
ip6_sprintf(&ip6->ip6_src),
ip6_sprintf(&ip6->ip6_dst),
ip6->ip6_nxt, if_name(m->m_pkthdr.rcvif),
if_name(rt->rt_ifp));
}
/* we can just use rcvif in forwarding. */
origifp = m->m_pkthdr.rcvif;
}
else
origifp = rt->rt_ifp;
/*
* clear embedded scope identifiers if necessary.
* in6_clearscope will touch the addresses only when necessary.
*/
in6_clearscope(&ip6->ip6_src);
in6_clearscope(&ip6->ip6_dst);
/*
* Run through list of hooks for output packets.
*/
if ((error = pfil_run_hooks(inet6_pfil_hook, &m, rt->rt_ifp,
PFIL_OUT)) != 0)
goto senderr;
if (m == NULL)
goto freecopy;
ip6 = mtod(m, struct ip6_hdr *);
error = nd6_output(rt->rt_ifp, origifp, m, dst, rt);
if (error) {
in6_ifstat_inc(rt->rt_ifp, ifs6_out_discard);
IP6_STATINC(IP6_STAT_CANTFORWARD);
} else {
IP6_STATINC(IP6_STAT_FORWARD);
in6_ifstat_inc(rt->rt_ifp, ifs6_out_forward);
if (type)
IP6_STATINC(IP6_STAT_REDIRECTSENT);
else {
#ifdef GATEWAY
if (m->m_flags & M_CANFASTFWD)
ip6flow_create(&ip6_forward_rt, m);
#endif
if (mcopy)
goto freecopy;
}
}
senderr:
if (mcopy == NULL)
return;
switch (error) {
case 0:
if (type == ND_REDIRECT) {
icmp6_redirect_output(mcopy, rt);
return;
}
goto freecopy;
case EMSGSIZE:
/* xxx MTU is constant in PPP? */
goto freecopy;
case ENOBUFS:
/* Tell source to slow down like source quench in IP? */
goto freecopy;
case ENETUNREACH: /* shouldn't happen, checked above */
case EHOSTUNREACH:
case ENETDOWN:
case EHOSTDOWN:
default:
type = ICMP6_DST_UNREACH;
code = ICMP6_DST_UNREACH_ADDR;
break;
}
icmp6_error(mcopy, type, code, 0);
return;
freecopy:
m_freem(mcopy);
return;
}