/
ip6_input.c
1497 lines (1351 loc) · 38.5 KB
/
ip6_input.c
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/* $OpenBSD: ip6_input.c,v 1.102 2011/08/04 16:40:08 bluhm Exp $ */
/* $KAME: ip6_input.c,v 1.188 2001/03/29 05:34:31 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.
*/
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ip_input.c 8.2 (Berkeley) 1/4/94
*/
#include "pf.h"
#include "carp.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/proc.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#ifdef INET
#include <netinet/ip.h>
#endif
#include <netinet/in_pcb.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/nd6.h>
#include <netinet6/ip6protosw.h>
#include "faith.h"
#include "gif.h"
#include "bpfilter.h"
#ifdef MROUTING
#include <netinet6/ip6_mroute.h>
#endif
#if NPF > 0
#include <net/pfvar.h>
#endif
#if NCARP > 0
#include <netinet/in_var.h>
#include <netinet/ip_carp.h>
#endif
extern struct domain inet6domain;
extern struct ip6protosw inet6sw[];
u_char ip6_protox[IPPROTO_MAX];
static int ip6qmaxlen = IFQ_MAXLEN;
struct in6_ifaddr *in6_ifaddr;
struct ifqueue ip6intrq;
struct ip6stat ip6stat;
void ip6_init2(void *);
int ip6_check_rh0hdr(struct mbuf *);
int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
/*
* IP6 initialization: fill in IP6 protocol switch table.
* All protocols not implemented in kernel go to raw IP6 protocol handler.
*/
void
ip6_init(void)
{
struct ip6protosw *pr;
int i;
pr = (struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
if (pr == 0)
panic("ip6_init");
for (i = 0; i < IPPROTO_MAX; i++)
ip6_protox[i] = pr - inet6sw;
for (pr = (struct ip6protosw *)inet6domain.dom_protosw;
pr < (struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
if (pr->pr_domain->dom_family == PF_INET6 &&
pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW &&
pr->pr_protocol < IPPROTO_MAX)
ip6_protox[pr->pr_protocol] = pr - inet6sw;
IFQ_SET_MAXLEN(&ip6intrq, ip6qmaxlen);
ip6_randomid_init();
nd6_init();
frag6_init();
ip6_init2((void *)0);
}
void
ip6_init2(void *dummy)
{
/* nd6_timer_init */
bzero(&nd6_timer_ch, sizeof(nd6_timer_ch));
timeout_set(&nd6_timer_ch, nd6_timer, NULL);
timeout_add_sec(&nd6_timer_ch, 1);
}
/*
* IP6 input interrupt handling. Just pass the packet to ip6_input.
*/
void
ip6intr(void)
{
int s;
struct mbuf *m;
for (;;) {
s = splnet();
IF_DEQUEUE(&ip6intrq, m);
splx(s);
if (m == NULL)
return;
ip6_input(m);
}
}
extern struct route_in6 ip6_forward_rt;
void
ip6_input(struct mbuf *m)
{
struct ip6_hdr *ip6;
int off = sizeof(struct ip6_hdr), nest;
u_int32_t plen;
u_int32_t rtalert = ~0;
int nxt, ours = 0;
struct ifnet *deliverifp = NULL;
#if NPF > 0
struct in6_addr odst;
#endif
int srcrt = 0, isanycast = 0;
u_int rtableid = 0;
/*
* mbuf statistics by kazu
*/
if (m->m_flags & M_EXT) {
if (m->m_next)
ip6stat.ip6s_mext2m++;
else
ip6stat.ip6s_mext1++;
} else {
if (m->m_next) {
if (m->m_flags & M_LOOP) {
ip6stat.ip6s_m2m[lo0ifp->if_index]++; /*XXX*/
} else if (m->m_pkthdr.rcvif->if_index < nitems(ip6stat.ip6s_m2m))
ip6stat.ip6s_m2m[m->m_pkthdr.rcvif->if_index]++;
else
ip6stat.ip6s_m2m[0]++;
} else
ip6stat.ip6s_m1++;
}
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_receive);
ip6stat.ip6s_total++;
if (m->m_len < sizeof(struct ip6_hdr)) {
struct ifnet *inifp;
inifp = m->m_pkthdr.rcvif;
if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
ip6stat.ip6s_toosmall++;
in6_ifstat_inc(inifp, ifs6_in_hdrerr);
return;
}
}
ip6 = mtod(m, struct ip6_hdr *);
if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
ip6stat.ip6s_badvers++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
goto bad;
}
#if NCARP > 0
if (m->m_pkthdr.rcvif->if_type == IFT_CARP &&
ip6->ip6_nxt != IPPROTO_ICMPV6 &&
carp_lsdrop(m, AF_INET6, ip6->ip6_src.s6_addr32,
ip6->ip6_dst.s6_addr32))
goto bad;
#endif
ip6stat.ip6s_nxthist[ip6->ip6_nxt]++;
/*
* Check against address spoofing/corruption.
*/
if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
/*
* XXX: "badscope" is not very suitable for a multicast source.
*/
ip6stat.ip6s_badscope++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
goto bad;
}
if ((IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) &&
(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
ip6stat.ip6s_badscope++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
goto bad;
}
if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
!(m->m_flags & M_LOOP)) {
/*
* In this case, the packet should come from the loopback
* interface. However, we cannot just check the if_flags,
* because ip6_mloopback() passes the "actual" interface
* as the outgoing/incoming interface.
*/
ip6stat.ip6s_badscope++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
goto bad;
}
/*
* The following check is not documented in specs. A malicious
* party may be able to use IPv4 mapped addr to confuse tcp/udp stack
* and bypass security checks (act as if it was from 127.0.0.1 by using
* IPv6 src ::ffff:127.0.0.1). Be cautious.
*
* This check chokes if we are in an SIIT cloud. As none of BSDs
* support IPv4-less kernel compilation, we cannot support SIIT
* environment at all. So, it makes more sense for us to reject any
* malicious packets for non-SIIT environment, than try to do a
* partial support for SIIT environment.
*/
if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
ip6stat.ip6s_badscope++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
goto bad;
}
#if 0
/*
* Reject packets with IPv4 compatible addresses (auto tunnel).
*
* The code forbids auto tunnel relay case in RFC1933 (the check is
* stronger than RFC1933). We may want to re-enable it if mech-xx
* is revised to forbid relaying case.
*/
if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
ip6stat.ip6s_badscope++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
goto bad;
}
#endif
if (ip6_check_rh0hdr(m)) {
ip6stat.ip6s_badoptions++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, 0);
/* m is already freed */
return;
}
#if NPF > 0
/*
* Packet filter
*/
odst = ip6->ip6_dst;
if (pf_test(AF_INET6, PF_IN, m->m_pkthdr.rcvif, &m, NULL) != PF_PASS)
goto bad;
if (m == NULL)
return;
ip6 = mtod(m, struct ip6_hdr *);
srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
#endif
if (IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) {
ours = 1;
deliverifp = m->m_pkthdr.rcvif;
goto hbhcheck;
}
/* drop packets if interface ID portion is already filled */
if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src) &&
ip6->ip6_src.s6_addr16[1]) {
ip6stat.ip6s_badscope++;
goto bad;
}
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst) &&
ip6->ip6_dst.s6_addr16[1]) {
ip6stat.ip6s_badscope++;
goto bad;
}
}
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
ip6->ip6_src.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
ip6->ip6_dst.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
/*
* We use rt->rt_ifp to determine if the address is ours or not.
* If rt_ifp is lo0, the address is ours.
* The problem here is, rt->rt_ifp for fe80::%lo0/64 is set to lo0,
* so any address under fe80::%lo0/64 will be mistakenly considered
* local. The special case is supplied to handle the case properly
* by actually looking at interface addresses
* (using in6ifa_ifpwithaddr).
*/
if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) != 0 &&
IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst)) {
if (!in6ifa_ifpwithaddr(m->m_pkthdr.rcvif, &ip6->ip6_dst)) {
icmp6_error(m, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_ADDR, 0);
/* m is already freed */
return;
}
ours = 1;
deliverifp = m->m_pkthdr.rcvif;
goto hbhcheck;
}
if (m->m_pkthdr.pf.flags & PF_TAG_DIVERTED) {
ours = 1;
deliverifp = m->m_pkthdr.rcvif;
goto hbhcheck;
}
/*
* Multicast check
*/
if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
struct in6_multi *in6m = 0;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_mcast);
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
IN6_LOOKUP_MULTI(ip6->ip6_dst, m->m_pkthdr.rcvif, in6m);
if (in6m)
ours = 1;
#ifdef MROUTING
else if (!ip6_mforwarding || !ip6_mrouter)
#else
else
#endif
{
ip6stat.ip6s_notmember++;
if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
ip6stat.ip6s_cantforward++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
goto bad;
}
deliverifp = m->m_pkthdr.rcvif;
goto hbhcheck;
}
#if NPF > 0
rtableid = m->m_pkthdr.rdomain;
#endif
/*
* Unicast check
*/
if (ip6_forward_rt.ro_rt != NULL &&
(ip6_forward_rt.ro_rt->rt_flags & RTF_UP) != 0 &&
IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
&ip6_forward_rt.ro_dst.sin6_addr) &&
rtableid == ip6_forward_rt.ro_tableid)
ip6stat.ip6s_forward_cachehit++;
else {
if (ip6_forward_rt.ro_rt) {
/* route is down or destination is different */
ip6stat.ip6s_forward_cachemiss++;
RTFREE(ip6_forward_rt.ro_rt);
ip6_forward_rt.ro_rt = 0;
}
bzero(&ip6_forward_rt.ro_dst, sizeof(struct sockaddr_in6));
ip6_forward_rt.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
ip6_forward_rt.ro_dst.sin6_family = AF_INET6;
ip6_forward_rt.ro_dst.sin6_addr = ip6->ip6_dst;
ip6_forward_rt.ro_tableid = rtableid;
rtalloc_mpath((struct route *)&ip6_forward_rt,
&ip6->ip6_src.s6_addr32[0]);
}
#define rt6_key(r) ((struct sockaddr_in6 *)((r)->rt_nodes->rn_key))
/*
* Accept the packet if the forwarding interface to the destination
* according to the routing table is the loopback interface,
* unless the associated route has a gateway.
* Note that this approach causes to accept a packet if there is a
* route to the loopback interface for the destination of the packet.
* But we think it's even useful in some situations, e.g. when using
* a special daemon which wants to intercept the packet.
*/
if (ip6_forward_rt.ro_rt &&
(ip6_forward_rt.ro_rt->rt_flags &
(RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
#if 0
/*
* The check below is redundant since the comparison of
* the destination and the key of the rtentry has
* already done through looking up the routing table.
*/
IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
&rt6_key(ip6_forward_rt.ro_rt)->sin6_addr) &&
#endif
ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_LOOP) {
struct in6_ifaddr *ia6 =
(struct in6_ifaddr *)ip6_forward_rt.ro_rt->rt_ifa;
if (ia6->ia6_flags & IN6_IFF_ANYCAST)
isanycast = 1;
/*
* packets to a tentative, duplicated, or somehow invalid
* address must not be accepted.
*/
if (!(ia6->ia6_flags & IN6_IFF_NOTREADY)) {
/* this address is ready */
ours = 1;
deliverifp = ia6->ia_ifp; /* correct? */
goto hbhcheck;
} else {
/* address is not ready, so discard the packet. */
nd6log((LOG_INFO,
"ip6_input: packet to an unready address %s->%s\n",
ip6_sprintf(&ip6->ip6_src),
ip6_sprintf(&ip6->ip6_dst)));
goto bad;
}
}
/*
* FAITH (Firewall Aided Internet Translator)
*/
#if defined(NFAITH) && 0 < NFAITH
if (ip6_keepfaith) {
if (ip6_forward_rt.ro_rt && ip6_forward_rt.ro_rt->rt_ifp
&& ip6_forward_rt.ro_rt->rt_ifp->if_type == IFT_FAITH) {
/* XXX do we need more sanity checks? */
ours = 1;
deliverifp = ip6_forward_rt.ro_rt->rt_ifp; /*faith*/
goto hbhcheck;
}
}
#endif
#if 0
{
/*
* Last resort: check in6_ifaddr for incoming interface.
* The code is here until I update the "goto ours hack" code above
* working right.
*/
struct ifaddr *ifa;
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) {
if (ifa->ifa_addr == NULL)
continue; /* just for safety */
if (ifa->ifa_addr->sa_family != AF_INET6)
continue;
if (IN6_ARE_ADDR_EQUAL(IFA_IN6(ifa), &ip6->ip6_dst)) {
ours = 1;
deliverifp = ifa->ifa_ifp;
goto hbhcheck;
}
}
}
#endif
#if NCARP > 0
if (m->m_pkthdr.rcvif->if_type == IFT_CARP &&
ip6->ip6_nxt == IPPROTO_ICMPV6 &&
carp_lsdrop(m, AF_INET6, ip6->ip6_src.s6_addr32,
ip6->ip6_dst.s6_addr32))
goto bad;
#endif
/*
* Now there is no reason to process the packet if it's not our own
* and we're not a router.
*/
if (!ip6_forwarding) {
ip6stat.ip6s_cantforward++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
goto bad;
}
hbhcheck:
/*
* Process Hop-by-Hop options header if it's contained.
* m may be modified in ip6_hopopts_input().
* If a JumboPayload option is included, plen will also be modified.
*/
plen = (u_int32_t)ntohs(ip6->ip6_plen);
if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
struct ip6_hbh *hbh;
if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
#if 0 /*touches NULL pointer*/
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
#endif
return; /* m have already been freed */
}
/* adjust pointer */
ip6 = mtod(m, struct ip6_hdr *);
/*
* if the payload length field is 0 and the next header field
* indicates Hop-by-Hop Options header, then a Jumbo Payload
* option MUST be included.
*/
if (ip6->ip6_plen == 0 && plen == 0) {
/*
* Note that if a valid jumbo payload option is
* contained, ip6_hoptops_input() must set a valid
* (non-zero) payload length to the variable plen.
*/
ip6stat.ip6s_badoptions++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_discard);
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_hdrerr);
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
(caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
return;
}
IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
sizeof(struct ip6_hbh));
if (hbh == NULL) {
ip6stat.ip6s_tooshort++;
return;
}
nxt = hbh->ip6h_nxt;
/*
* accept the packet if a router alert option is included
* and we act as an IPv6 router.
*/
if (rtalert != ~0 && ip6_forwarding)
ours = 1;
} else
nxt = ip6->ip6_nxt;
/*
* Check that the amount of data in the buffers
* is as at least much as the IPv6 header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
ip6stat.ip6s_tooshort++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
goto bad;
}
if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = sizeof(struct ip6_hdr) + plen;
m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
} else
m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
}
/*
* Forward if desirable.
*/
if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
/*
* If we are acting as a multicast router, all
* incoming multicast packets are passed to the
* kernel-level multicast forwarding function.
* The packet is returned (relatively) intact; if
* ip6_mforward() returns a non-zero value, the packet
* must be discarded, else it may be accepted below.
*/
#ifdef MROUTING
if (ip6_mforwarding && ip6_mrouter &&
ip6_mforward(ip6, m->m_pkthdr.rcvif, m)) {
ip6stat.ip6s_cantforward++;
m_freem(m);
return;
}
#endif
if (!ours) {
m_freem(m);
return;
}
} else if (!ours) {
ip6_forward(m, srcrt);
return;
}
ip6 = mtod(m, struct ip6_hdr *);
/*
* Malicious party may be able to use IPv4 mapped addr to confuse
* tcp/udp stack and bypass security checks (act as if it was from
* 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1). Be cautious.
*
* For SIIT end node behavior, you may want to disable the check.
* However, you will become vulnerable to attacks using IPv4 mapped
* source.
*/
if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
ip6stat.ip6s_badscope++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_addrerr);
goto bad;
}
/*
* Tell launch routine the next header
*/
ip6stat.ip6s_delivered++;
in6_ifstat_inc(deliverifp, ifs6_in_deliver);
nest = 0;
while (nxt != IPPROTO_DONE) {
if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
ip6stat.ip6s_toomanyhdr++;
goto bad;
}
/*
* protection against faulty packet - there should be
* more sanity checks in header chain processing.
*/
if (m->m_pkthdr.len < off) {
ip6stat.ip6s_tooshort++;
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
goto bad;
}
/* draft-itojun-ipv6-tcp-to-anycast */
if (isanycast && nxt == IPPROTO_TCP) {
if (m->m_len >= sizeof(struct ip6_hdr)) {
ip6 = mtod(m, struct ip6_hdr *);
icmp6_error(m, ICMP6_DST_UNREACH,
ICMP6_DST_UNREACH_ADDR,
(caddr_t)&ip6->ip6_dst - (caddr_t)ip6);
break;
} else
goto bad;
}
nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
}
return;
bad:
m_freem(m);
}
/* scan packet for RH0 routing header. Mostly stolen from pf.c:pf_test() */
int
ip6_check_rh0hdr(struct mbuf *m)
{
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
struct ip6_rthdr rthdr;
struct ip6_ext opt6;
u_int8_t proto = ip6->ip6_nxt;
int done = 0, lim, off, rh_cnt = 0;
off = ((caddr_t)ip6 - m->m_data) + sizeof(struct ip6_hdr);
lim = min(m->m_pkthdr.len, ntohs(ip6->ip6_plen) + sizeof(*ip6));
do {
switch (proto) {
case IPPROTO_ROUTING:
if (rh_cnt++) {
/* more then one rh header present */
return (1);
}
if (off + sizeof(rthdr) > lim) {
/* packet to short to make sense */
return (1);
}
m_copydata(m, off, sizeof(rthdr), (caddr_t)&rthdr);
if (rthdr.ip6r_type == IPV6_RTHDR_TYPE_0)
return (1);
off += (rthdr.ip6r_len + 1) * 8;
proto = rthdr.ip6r_nxt;
break;
case IPPROTO_AH:
case IPPROTO_HOPOPTS:
case IPPROTO_DSTOPTS:
/* get next header and header length */
if (off + sizeof(opt6) > lim) {
/*
* Packet to short to make sense, we could
* reject the packet but as a router we
* should not do that so forward it.
*/
return (0);
}
m_copydata(m, off, sizeof(opt6), (caddr_t)&opt6);
if (proto == IPPROTO_AH)
off += (opt6.ip6e_len + 2) * 4;
else
off += (opt6.ip6e_len + 1) * 8;
proto = opt6.ip6e_nxt;
break;
case IPPROTO_FRAGMENT:
default:
/* end of header stack */
done = 1;
break;
}
} while (!done);
return (0);
}
/*
* Hop-by-Hop options header processing. If a valid jumbo payload option is
* included, the real payload length will be stored in plenp.
*
* rtalertp - XXX: should be stored in a more smart way
*/
int
ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp, struct mbuf **mp,
int *offp)
{
struct mbuf *m = *mp;
int off = *offp, hbhlen;
struct ip6_hbh *hbh;
/* validation of the length of the header */
IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
if (hbh == NULL) {
ip6stat.ip6s_tooshort++;
return -1;
}
hbhlen = (hbh->ip6h_len + 1) << 3;
IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
hbhlen);
if (hbh == NULL) {
ip6stat.ip6s_tooshort++;
return -1;
}
off += hbhlen;
hbhlen -= sizeof(struct ip6_hbh);
if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
hbhlen, rtalertp, plenp) < 0)
return (-1);
*offp = off;
*mp = m;
return (0);
}
/*
* Search header for all Hop-by-hop options and process each option.
* This function is separate from ip6_hopopts_input() in order to
* handle a case where the sending node itself process its hop-by-hop
* options header. In such a case, the function is called from ip6_output().
*
* The function assumes that hbh header is located right after the IPv6 header
* (RFC2460 p7), opthead is pointer into data content in m, and opthead to
* opthead + hbhlen is located in continuous memory region.
*/
int
ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen,
u_int32_t *rtalertp, u_int32_t *plenp)
{
struct ip6_hdr *ip6;
int optlen = 0;
u_int8_t *opt = opthead;
u_int16_t rtalert_val;
u_int32_t jumboplen;
const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);
for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
switch (*opt) {
case IP6OPT_PAD1:
optlen = 1;
break;
case IP6OPT_PADN:
if (hbhlen < IP6OPT_MINLEN) {
ip6stat.ip6s_toosmall++;
goto bad;
}
optlen = *(opt + 1) + 2;
break;
case IP6OPT_ROUTER_ALERT:
/* XXX may need check for alignment */
if (hbhlen < IP6OPT_RTALERT_LEN) {
ip6stat.ip6s_toosmall++;
goto bad;
}
if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
/* XXX stat */
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
erroff + opt + 1 - opthead);
return (-1);
}
optlen = IP6OPT_RTALERT_LEN;
bcopy((caddr_t)(opt + 2), (caddr_t)&rtalert_val, 2);
*rtalertp = ntohs(rtalert_val);
break;
case IP6OPT_JUMBO:
/* XXX may need check for alignment */
if (hbhlen < IP6OPT_JUMBO_LEN) {
ip6stat.ip6s_toosmall++;
goto bad;
}
if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
/* XXX stat */
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
erroff + opt + 1 - opthead);
return (-1);
}
optlen = IP6OPT_JUMBO_LEN;
/*
* IPv6 packets that have non 0 payload length
* must not contain a jumbo payload option.
*/
ip6 = mtod(m, struct ip6_hdr *);
if (ip6->ip6_plen) {
ip6stat.ip6s_badoptions++;
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
erroff + opt - opthead);
return (-1);
}
/*
* We may see jumbolen in unaligned location, so
* we'd need to perform bcopy().
*/
bcopy(opt + 2, &jumboplen, sizeof(jumboplen));
jumboplen = (u_int32_t)htonl(jumboplen);
#if 1
/*
* if there are multiple jumbo payload options,
* *plenp will be non-zero and the packet will be
* rejected.
* the behavior may need some debate in ipngwg -
* multiple options does not make sense, however,
* there's no explicit mention in specification.
*/
if (*plenp != 0) {
ip6stat.ip6s_badoptions++;
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
erroff + opt + 2 - opthead);
return (-1);
}
#endif
/*
* jumbo payload length must be larger than 65535.
*/
if (jumboplen <= IPV6_MAXPACKET) {
ip6stat.ip6s_badoptions++;
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
erroff + opt + 2 - opthead);
return (-1);
}
*plenp = jumboplen;
break;
default: /* unknown option */
if (hbhlen < IP6OPT_MINLEN) {
ip6stat.ip6s_toosmall++;
goto bad;
}
optlen = ip6_unknown_opt(opt, m,
erroff + opt - opthead);
if (optlen == -1)
return (-1);
optlen += 2;
break;
}
}
return (0);
bad:
m_freem(m);
return (-1);
}
/*
* Unknown option processing.
* The third argument `off' is the offset from the IPv6 header to the option,
* which allows returning an ICMPv6 error even if the IPv6 header and the
* option header are not continuous.
*/
int
ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
{
struct ip6_hdr *ip6;
switch (IP6OPT_TYPE(*optp)) {
case IP6OPT_TYPE_SKIP: /* ignore the option */
return ((int)*(optp + 1));
case IP6OPT_TYPE_DISCARD: /* silently discard */
m_freem(m);
return (-1);
case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
ip6stat.ip6s_badoptions++;
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
return (-1);
case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
ip6stat.ip6s_badoptions++;
ip6 = mtod(m, struct ip6_hdr *);
if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
(m->m_flags & (M_BCAST|M_MCAST)))
m_freem(m);