/*
* Input an Neighbor Solicitation Message.
*
* Based on RFC 2461
* Based on RFC 2462 (duplicated address detection)
*/
void
nd6_ns_input(struct mbuf *m, int off, int icmp6len)
{
struct ifnet *ifp = m->m_pkthdr.rcvif;
struct ifnet *cmpifp;
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;
union nd_opts ndopts;
struct sockaddr_dl *proxydl = NULL;
/*
* Collapse interfaces to the bridge for comparison and
* mac (llinfo) purposes.
*/
cmpifp = ifp;
if (ifp->if_bridge)
cmpifp = ifp->if_bridge;
#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.icp6s_tooshort++;
return;
}
#endif
ip6 = mtod(m, struct ip6_hdr *); /* adjust pointer for safety */
taddr6 = nd_ns->nd_ns_target;
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 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 (!nd6_onlink_ns_rfc4861) {
/*
* Make sure the source address is from a neighbor's address.
*
* XXX probably only need to check cmpifp.
*/
if (in6ifa_ifplocaladdr(cmpifp, &saddr6) == NULL &&
in6ifa_ifplocaladdr(ifp, &saddr6) == NULL) {
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;
}
if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
taddr6.s6_addr16[1] = htons(ifp->if_index);
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 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 or anycast address for which I'm offering proxy
* service.
* (3) "tentative" address on which DAD is being performed.
*/
/* (1) and (3) check. */
#ifdef CARP
if (ifp->if_carp)
ifa = carp_iamatch6(ifp->if_carp, &taddr6);
if (!ifa)
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#else
ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
#endif
/*
* (2) Check proxying. Requires ip6_forwarding to be turned on.
*
* If the packet is anycast the target route must be on a
* different interface because the anycast will get anything
* on the current interface.
*
* If the packet is unicast the target route may be on the
* same interface. If the gateway is a (typically manually
* configured) link address we can directly offer it.
* XXX for now we don't do this but instead offer ours and
* presumably relay.
*
* WARNING! Since this is a subnet proxy the interface proxying
* the ND6 must be in promiscuous mode or it will not see the
* solicited multicast requests for various hosts being proxied.
*
* WARNING! Since this is a subnet proxy we have to treat bridge
* interfaces as being the bridge itself so we do not proxy-nd6
* between bridge interfaces (which are effectively switched).
*
* (In the specific-host-proxy case via RTF_ANNOUNCE, which is
* a bitch to configure, a specific multicast route is already
* added for that host <-- NOT RECOMMENDED).
*/
if (!ifa && ip6_forwarding) {
struct rtentry *rt;
struct sockaddr_in6 tsin6;
struct ifnet *rtifp;
bzero(&tsin6, sizeof tsin6);
tsin6.sin6_len = sizeof(struct sockaddr_in6);
tsin6.sin6_family = AF_INET6;
tsin6.sin6_addr = taddr6;
rt = rtpurelookup((struct sockaddr *)&tsin6);
rtifp = rt ? rt->rt_ifp : NULL;
if (rtifp && rtifp->if_bridge)
rtifp = rtifp->if_bridge;
if (rt != NULL &&
(cmpifp != rtifp ||
(cmpifp == rtifp && (m->m_flags & M_MCAST) == 0))
) {
ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(cmpifp,
IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
nd6log((LOG_INFO,
"nd6_ns_input: nd6 proxy %s(%s)<-%s ifa %p\n",
if_name(cmpifp), if_name(ifp),
if_name(rtifp), ifa));
if (ifa) {
proxy = 1;
/*
* Manual link address on same interface
* w/announce flag will proxy-arp using
* target mac, else our mac is used.
*/
if (cmpifp == rtifp &&
(rt->rt_flags & RTF_ANNOUNCE) &&
rt->rt_gateway->sa_family == AF_LINK) {
proxydl = SDL(rt->rt_gateway);
}
}
}
if (rt != NULL)
--rt->rt_refcnt;
}
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 && ((cmpifp->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), cmpifp->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
* duplicated 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)) {
saddr6 = kin6addr_linklocal_allnodes;
saddr6.s6_addr16[1] = htons(cmpifp->if_index);
nd6_na_output(cmpifp, &saddr6, &taddr6,
((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
(ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
tlladdr, (struct sockaddr *)proxydl);
goto freeit;
}
nd6_cache_lladdr(cmpifp, &saddr6, lladdr, lladdrlen,
ND_NEIGHBOR_SOLICIT, 0);
nd6_na_output(ifp, &saddr6, &taddr6,
((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE) |
(ip6_forwarding ? ND_NA_FLAG_ROUTER : 0) | ND_NA_FLAG_SOLICITED,
tlladdr, (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)));
icmp6stat.icp6s_badns++;
m_freem(m);
}
/*
* Do what we need to do when inserting a route.
*/
static struct radix_node *
in6_addroute(char *key, char *mask, struct radix_node_head *head,
struct radix_node *treenodes)
{
struct rtentry *rt = (struct rtentry *)treenodes;
struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt);
struct radix_node *ret;
/*
* For IPv6, all unicast non-host routes are automatically cloning.
*/
if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
rt->rt_flags |= RTF_MULTICAST;
if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) {
rt->rt_flags |= RTF_PRCLONING;
}
/*
* A little bit of help for both IPv6 output and input:
* For local addresses, we make sure that RTF_LOCAL is set,
* with the thought that this might one day be used to speed up
* ip_input().
*
* We also mark routes to multicast addresses as such, because
* it's easy to do and might be useful (but this is much more
* dubious since it's so easy to inspect the address). (This
* is done above.)
*
* XXX
* should elaborate the code.
*/
if (rt->rt_flags & RTF_HOST) {
if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr)
->sin6_addr,
&sin6->sin6_addr)) {
rt->rt_flags |= RTF_LOCAL;
}
}
if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU) &&
rt->rt_ifp != NULL)
rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
ret = rn_addroute(key, mask, head, treenodes);
if (ret == NULL && rt->rt_flags & RTF_HOST) {
struct rtentry *rt2;
/*
* We are trying to add a host route, but can't.
* Find out if it is because of an
* ARP entry and delete it if so.
*/
rt2 = rtpurelookup((struct sockaddr *)sin6);
if (rt2 != NULL) {
--rt2->rt_refcnt;
if (rt2->rt_flags & RTF_LLINFO &&
rt2->rt_flags & RTF_HOST &&
rt2->rt_gateway &&
rt2->rt_gateway->sa_family == AF_LINK) {
rtrequest(RTM_DELETE, rt_key(rt2),
rt2->rt_gateway, rt_mask(rt2),
rt2->rt_flags, NULL);
ret = rn_addroute(key, mask, head, treenodes);
}
}
} else if (ret == NULL && rt->rt_flags & RTF_CLONING) {
struct rtentry *rt2;
/*
* We are trying to add a net route, but can't.
* The following case should be allowed, so we'll make a
* special check for this:
* Two IPv6 addresses with the same prefix is assigned
* to a single interrface.
* # ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1)
* # ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2)
* In this case, (*1) and (*2) want to add the same
* net route entry, 3ffe:0501:: -> if0.
* This case should not raise an error.
*/
rt2 = rtpurelookup((struct sockaddr *)sin6);
if (rt2 != NULL) {
if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY))
== RTF_CLONING &&
rt2->rt_gateway &&
rt2->rt_gateway->sa_family == AF_LINK &&
rt2->rt_ifp == rt->rt_ifp) {
ret = rt2->rt_nodes;
}
--rt2->rt_refcnt;
}
}
return ret;
}
