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ip6_input.c
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ip6_input.c
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/* $OpenBSD: ip6_input.c,v 1.219 2019/08/21 15:32:18 florian 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/mbuf.h>
#include <sys/domain.h>
#include <sys/sysctl.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/timeout.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/task.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/netisr.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet6/in6_var.h>
#include <netinet6/in6_ifattach.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/nd6.h>
#include <netinet6/ip6protosw.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/ip_carp.h>
#endif
struct cpumem *ip6counters;
uint8_t ip6_soiikey[IP6_SOIIKEY_LEN];
int ip6_ours(struct mbuf **, int *, int, int);
int ip6_check_rh0hdr(struct mbuf *, int *);
int ip6_hbhchcheck(struct mbuf *, int *, int *, int *);
int ip6_hopopts_input(u_int32_t *, u_int32_t *, struct mbuf **, int *);
struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
int ip6_sysctl_soiikey(void *, size_t *, void *, size_t);
static struct mbuf_queue ip6send_mq;
static void ip6_send_dispatch(void *);
static struct task ip6send_task =
TASK_INITIALIZER(ip6_send_dispatch, &ip6send_mq);
/*
* IP6 initialization: fill in IP6 protocol switch table.
* All protocols not implemented in kernel go to raw IP6 protocol handler.
*/
void
ip6_init(void)
{
const struct protosw *pr;
int i;
pr = pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
if (pr == NULL)
panic("ip6_init");
for (i = 0; i < IPPROTO_MAX; i++)
ip6_protox[i] = pr - inet6sw;
for (pr = inet6domain.dom_protosw;
pr < 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;
ip6_randomid_init();
nd6_init();
frag6_init();
mq_init(&ip6send_mq, 64, IPL_SOFTNET);
ip6counters = counters_alloc(ip6s_ncounters);
}
void
ipv6_input(struct ifnet *ifp, struct mbuf *m)
{
int off, nxt;
off = 0;
nxt = ip6_input_if(&m, &off, IPPROTO_IPV6, AF_UNSPEC, ifp);
KASSERT(nxt == IPPROTO_DONE);
}
int
ip6_input_if(struct mbuf **mp, int *offp, int nxt, int af, struct ifnet *ifp)
{
struct mbuf *m = *mp;
struct ip6_hdr *ip6;
struct sockaddr_in6 sin6;
struct rtentry *rt = NULL;
int ours = 0;
u_int16_t src_scope, dst_scope;
#if NPF > 0
struct in6_addr odst;
#endif
int srcrt = 0;
KASSERT(*offp == 0);
ip6stat_inc(ip6s_total);
if (m->m_len < sizeof(struct ip6_hdr)) {
if ((m = *mp = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
ip6stat_inc(ip6s_toosmall);
goto bad;
}
}
ip6 = mtod(m, struct ip6_hdr *);
if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
ip6stat_inc(ip6s_badvers);
goto bad;
}
#if NCARP > 0
if (carp_lsdrop(ifp, m, AF_INET6, ip6->ip6_src.s6_addr32,
ip6->ip6_dst.s6_addr32, (ip6->ip6_nxt == IPPROTO_ICMPV6 ? 0 : 1)))
goto bad;
#endif
ip6stat_inc(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_inc(ip6s_badscope);
goto bad;
}
if ((IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) &&
(ifp->if_flags & IFF_LOOPBACK) == 0) {
ip6stat_inc(ip6s_badscope);
goto bad;
}
/* Drop packets if interface ID portion is already filled. */
if (((IN6_IS_SCOPE_EMBED(&ip6->ip6_src) && ip6->ip6_src.s6_addr16[1]) ||
(IN6_IS_SCOPE_EMBED(&ip6->ip6_dst) && ip6->ip6_dst.s6_addr16[1])) &&
(ifp->if_flags & IFF_LOOPBACK) == 0) {
ip6stat_inc(ip6s_badscope);
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_inc(ip6s_badscope);
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_inc(ip6s_badscope);
goto bad;
}
/*
* Reject packets with IPv4 compatible addresses (auto tunnel).
*
* The code forbids automatic tunneling as per RFC4213.
*/
if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
ip6stat_inc(ip6s_badscope);
goto bad;
}
/*
* If the packet has been received on a loopback interface it
* can be destinated to any local address, not necessarily to
* an address configured on `ifp'.
*/
if (ifp->if_flags & IFF_LOOPBACK) {
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src)) {
src_scope = ip6->ip6_src.s6_addr16[1];
ip6->ip6_src.s6_addr16[1] = 0;
}
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst)) {
dst_scope = ip6->ip6_dst.s6_addr16[1];
ip6->ip6_dst.s6_addr16[1] = 0;
}
}
#if NPF > 0
/*
* Packet filter
*/
odst = ip6->ip6_dst;
if (pf_test(AF_INET6, PF_IN, ifp, mp) != PF_PASS)
goto bad;
m = *mp;
if (m == NULL)
goto bad;
ip6 = mtod(m, struct ip6_hdr *);
srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
#endif
/*
* Without embedded scope ID we cannot find link-local
* addresses in the routing table.
*/
if (ifp->if_flags & IFF_LOOPBACK) {
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
ip6->ip6_src.s6_addr16[1] = src_scope;
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
ip6->ip6_dst.s6_addr16[1] = dst_scope;
} else {
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
ip6->ip6_src.s6_addr16[1] = htons(ifp->if_index);
if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
}
/*
* Be more secure than RFC5095 and scan for type 0 routing headers.
* If pf has already scanned the header chain, do not do it twice.
*/
if (!(m->m_pkthdr.pf.flags & PF_TAG_PROCESSED) &&
ip6_check_rh0hdr(m, offp)) {
ip6stat_inc(ip6s_badoptions);
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, *offp);
m = *mp = NULL;
goto bad;
}
if (IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) {
nxt = ip6_ours(mp, offp, nxt, af);
goto out;
}
#if NPF > 0
if (pf_ouraddr(m) == 1) {
nxt = ip6_ours(mp, offp, nxt, af);
goto out;
}
#endif
/*
* Multicast check
*/
if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
/*
* Make sure M_MCAST is set. It should theoretically
* already be there, but let's play safe because upper
* layers check for this flag.
*/
m->m_flags |= M_MCAST;
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
if (in6_hasmulti(&ip6->ip6_dst, ifp))
ours = 1;
#ifdef MROUTING
if (ip6_mforwarding && ip6_mrouter[ifp->if_rdomain]) {
int error;
if (ip6_hbhchcheck(m, offp, &nxt, &ours))
goto out;
ip6 = mtod(m, struct ip6_hdr *);
/*
* 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.
*/
KERNEL_LOCK();
error = ip6_mforward(ip6, ifp, m);
KERNEL_UNLOCK();
if (error) {
ip6stat_inc(ip6s_cantforward);
goto bad;
}
if (ours) {
if (af == AF_UNSPEC) {
KERNEL_LOCK();
nxt = ip_deliver(mp, offp, nxt,
AF_INET6);
KERNEL_UNLOCK();
}
goto out;
}
goto bad;
}
#endif
if (!ours) {
ip6stat_inc(ip6s_notmember);
if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
ip6stat_inc(ip6s_cantforward);
goto bad;
}
nxt = ip6_ours(mp, offp, nxt, af);
goto out;
}
/*
* Unicast check
*/
memset(&sin6, 0, sizeof(struct sockaddr_in6));
sin6.sin6_len = sizeof(struct sockaddr_in6);
sin6.sin6_family = AF_INET6;
sin6.sin6_addr = ip6->ip6_dst;
rt = rtalloc_mpath(sin6tosa(&sin6), &ip6->ip6_src.s6_addr32[0],
m->m_pkthdr.ph_rtableid);
/*
* Accept the packet if the route to the destination is marked
* as local.
*/
if (rtisvalid(rt) && ISSET(rt->rt_flags, RTF_LOCAL)) {
struct in6_ifaddr *ia6 = ifatoia6(rt->rt_ifa);
if (ia6->ia6_flags & IN6_IFF_ANYCAST)
m->m_flags |= M_ACAST;
/*
* packets to a tentative, duplicated, or somehow invalid
* address must not be accepted.
*/
if ((ia6->ia6_flags & (IN6_IFF_TENTATIVE|IN6_IFF_DUPLICATED))) {
char src[INET6_ADDRSTRLEN], dst[INET6_ADDRSTRLEN];
inet_ntop(AF_INET6, &ip6->ip6_src, src, sizeof(src));
inet_ntop(AF_INET6, &ip6->ip6_dst, dst, sizeof(dst));
/* address is not ready, so discard the packet. */
nd6log((LOG_INFO,
"%s: packet to an unready address %s->%s\n",
__func__, src, dst));
goto bad;
} else {
nxt = ip6_ours(mp, offp, nxt, af);
goto out;
}
}
#if NCARP > 0
if (ip6->ip6_nxt == IPPROTO_ICMPV6 &&
carp_lsdrop(ifp, m, AF_INET6, ip6->ip6_src.s6_addr32,
ip6->ip6_dst.s6_addr32, 1))
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_inc(ip6s_cantforward);
goto bad;
}
if (ip6_hbhchcheck(m, offp, &nxt, &ours))
goto out;
if (ours) {
if (af == AF_UNSPEC) {
KERNEL_LOCK();
nxt = ip_deliver(mp, offp, nxt, AF_INET6);
KERNEL_UNLOCK();
}
goto out;
}
#ifdef IPSEC
if (ipsec_in_use) {
int rv;
rv = ipsec_forward_check(m, *offp, AF_INET6);
if (rv != 0) {
ip6stat_inc(ip6s_cantforward);
goto bad;
}
/*
* Fall through, forward packet. Outbound IPsec policy
* checking will occur in ip6_forward().
*/
}
#endif /* IPSEC */
ip6_forward(m, rt, srcrt);
*mp = NULL;
return IPPROTO_DONE;
bad:
nxt = IPPROTO_DONE;
m_freemp(mp);
out:
rtfree(rt);
return nxt;
}
int
ip6_ours(struct mbuf **mp, int *offp, int nxt, int af)
{
if (ip6_hbhchcheck(*mp, offp, &nxt, NULL))
return IPPROTO_DONE;
/* Check wheter we are already in a IPv4/IPv6 local deliver loop. */
if (af == AF_UNSPEC)
nxt = ip_deliver(mp, offp, nxt, AF_INET6);
return nxt;
}
int
ip6_hbhchcheck(struct mbuf *m, int *offp, int *nxtp, int *oursp)
{
struct ip6_hdr *ip6;
u_int32_t plen, rtalert = ~0;
ip6 = mtod(m, struct ip6_hdr *);
/*
* 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);
*offp = sizeof(struct ip6_hdr);
if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
struct ip6_hbh *hbh;
if (ip6_hopopts_input(&plen, &rtalert, &m, offp)) {
goto bad; /* 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_hopopts_input() must set a valid
* (non-zero) payload length to the variable plen.
*/
ip6stat_inc(ip6s_badoptions);
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_HEADER,
(caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
goto bad;
}
IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
sizeof(struct ip6_hbh));
if (hbh == NULL) {
ip6stat_inc(ip6s_tooshort);
goto bad;
}
*nxtp = 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 && oursp != NULL)
*oursp = 1;
} else
*nxtp = 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_inc(ip6s_tooshort);
m_freem(m);
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);
}
}
return (0);
bad:
*nxtp = IPPROTO_DONE;
return (-1);
}
/* scan packet for RH0 routing header. Mostly stolen from pf.c:pf_test() */
int
ip6_check_rh0hdr(struct mbuf *m, int *offp)
{
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:
*offp = off;
if (rh_cnt++) {
/* more than 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) {
*offp += offsetof(struct ip6_rthdr, ip6r_type);
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_inc(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_inc(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_inc(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_inc(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;
memcpy((caddr_t)&rtalert_val, (caddr_t)(opt + 2), 2);
*rtalertp = ntohs(rtalert_val);
break;
case IP6OPT_JUMBO:
/* XXX may need check for alignment */
if (hbhlen < IP6OPT_JUMBO_LEN) {
ip6stat_inc(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_inc(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 memcpy().
*/
memcpy(&jumboplen, opt + 2, 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_inc(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_inc(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_inc(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_inc(ip6s_badoptions);
icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
return (-1);
case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
ip6stat_inc(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);
else
icmp6_error(m, ICMP6_PARAM_PROB,
ICMP6_PARAMPROB_OPTION, off);
return (-1);
}
m_freem(m); /* XXX: NOTREACHED */
return (-1);
}
/*
* Create the "control" list for this pcb.
*
* The routine will be called from upper layer handlers like udp_input().
* Thus the routine assumes that the caller (udp_input) have already
* called IP6_EXTHDR_CHECK() and all the extension headers are located in the
* very first mbuf on the mbuf chain.
* We may want to add some infinite loop prevention or sanity checks for safety.
* (This applies only when you are using KAME mbuf chain restriction, i.e.
* you are using IP6_EXTHDR_CHECK() not m_pulldown())
*/
void
ip6_savecontrol(struct inpcb *in6p, struct mbuf *m, struct mbuf **mp)
{
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
if (in6p->inp_socket->so_options & SO_TIMESTAMP) {
struct timeval tv;
m_microtime(m, &tv);
*mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
SCM_TIMESTAMP, SOL_SOCKET);
if (*mp)
mp = &(*mp)->m_next;
}
/* RFC 2292 sec. 5 */
if ((in6p->inp_flags & IN6P_PKTINFO) != 0) {
struct in6_pktinfo pi6;
memcpy(&pi6.ipi6_addr, &ip6->ip6_dst, sizeof(struct in6_addr));
if (IN6_IS_SCOPE_EMBED(&pi6.ipi6_addr))
pi6.ipi6_addr.s6_addr16[1] = 0;
pi6.ipi6_ifindex = m ? m->m_pkthdr.ph_ifidx : 0;
*mp = sbcreatecontrol((caddr_t) &pi6,
sizeof(struct in6_pktinfo),
IPV6_PKTINFO, IPPROTO_IPV6);
if (*mp)
mp = &(*mp)->m_next;
}
if ((in6p->inp_flags & IN6P_HOPLIMIT) != 0) {
int hlim = ip6->ip6_hlim & 0xff;
*mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
IPV6_HOPLIMIT, IPPROTO_IPV6);
if (*mp)
mp = &(*mp)->m_next;
}
if ((in6p->inp_flags & IN6P_TCLASS) != 0) {
u_int32_t flowinfo;
int tclass;
flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
flowinfo >>= 20;
tclass = flowinfo & 0xff;
*mp = sbcreatecontrol((caddr_t)&tclass, sizeof(tclass),
IPV6_TCLASS, IPPROTO_IPV6);
if (*mp)
mp = &(*mp)->m_next;
}
/*
* IPV6_HOPOPTS socket option. Recall that we required super-user
* privilege for the option (see ip6_ctloutput), but it might be too
* strict, since there might be some hop-by-hop options which can be
* returned to normal user.
* See also RFC 2292 section 6 (or RFC 3542 section 8).
*/
if ((in6p->inp_flags & IN6P_HOPOPTS) != 0) {
/*
* Check if a hop-by-hop options header is contained in the
* received packet, and if so, store the options as ancillary
* data. Note that a hop-by-hop options header must be
* just after the IPv6 header, which is assured through the
* IPv6 input processing.
*/
struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
struct ip6_hbh *hbh;
int hbhlen = 0;
struct mbuf *ext;
ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
ip6->ip6_nxt);
if (ext == NULL) {
ip6stat_inc(ip6s_tooshort);
return;
}
hbh = mtod(ext, struct ip6_hbh *);
hbhlen = (hbh->ip6h_len + 1) << 3;
if (hbhlen != ext->m_len) {
m_freem(ext);
ip6stat_inc(ip6s_tooshort);
return;
}
/*
* XXX: We copy the whole header even if a
* jumbo payload option is included, the option which
* is to be removed before returning according to
* RFC2292.
* Note: this constraint is removed in RFC3542.
*/
*mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
IPV6_HOPOPTS,
IPPROTO_IPV6);
if (*mp)
mp = &(*mp)->m_next;
m_freem(ext);