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/* $NetBSD: ip_input.c,v 1.158 2002/09/23 13:43:27 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) 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Public Access Networks Corporation ("Panix"). It was developed under
* contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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 <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.158 2002/09/23 13:43:27 itojun Exp $");
#include "opt_gateway.h"
#include "opt_pfil_hooks.h"
#include "opt_ipsec.h"
#include "opt_mrouting.h"
#include "opt_inet_csum.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/pool.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/pfil.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
/* just for gif_ttl */
#include <netinet/in_gif.h>
#include "gif.h"
#include <net/if_gre.h>
#include "gre.h"
#ifdef MROUTING
#include <netinet/ip_mroute.h>
#endif
#ifdef IPSEC
#include <netinet6/ipsec.h>
#include <netkey/key.h>
#endif
#ifndef IPFORWARDING
#ifdef GATEWAY
#define IPFORWARDING 1 /* forward IP packets not for us */
#else /* GATEWAY */
#define IPFORWARDING 0 /* don't forward IP packets not for us */
#endif /* GATEWAY */
#endif /* IPFORWARDING */
#ifndef IPSENDREDIRECTS
#define IPSENDREDIRECTS 1
#endif
#ifndef IPFORWSRCRT
#define IPFORWSRCRT 1 /* forward source-routed packets */
#endif
#ifndef IPALLOWSRCRT
#define IPALLOWSRCRT 1 /* allow source-routed packets */
#endif
#ifndef IPMTUDISC
#define IPMTUDISC 1
#endif
#ifndef IPMTUDISCTIMEOUT
#define IPMTUDISCTIMEOUT (10 * 60) /* as per RFC 1191 */
#endif
/*
* Note: DIRECTED_BROADCAST is handled this way so that previous
* configuration using this option will Just Work.
*/
#ifndef IPDIRECTEDBCAST
#ifdef DIRECTED_BROADCAST
#define IPDIRECTEDBCAST 1
#else
#define IPDIRECTEDBCAST 0
#endif /* DIRECTED_BROADCAST */
#endif /* IPDIRECTEDBCAST */
int ipforwarding = IPFORWARDING;
int ipsendredirects = IPSENDREDIRECTS;
int ip_defttl = IPDEFTTL;
int ip_forwsrcrt = IPFORWSRCRT;
int ip_directedbcast = IPDIRECTEDBCAST;
int ip_allowsrcrt = IPALLOWSRCRT;
int ip_mtudisc = IPMTUDISC;
int ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
#ifdef DIAGNOSTIC
int ipprintfs = 0;
#endif
struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
extern struct domain inetdomain;
int ipqmaxlen = IFQ_MAXLEN;
u_long in_ifaddrhash; /* size of hash table - 1 */
int in_ifaddrentries; /* total number of addrs */
struct in_ifaddrhead in_ifaddr;
struct in_ifaddrhashhead *in_ifaddrhashtbl;
struct ifqueue ipintrq;
struct ipstat ipstat;
u_int16_t ip_id;
#ifdef PFIL_HOOKS
struct pfil_head inet_pfil_hook;
#endif
struct ipqhead ipq;
int ipq_locked;
int ip_nfragpackets = 0;
int ip_maxfragpackets = 200;
static __inline int ipq_lock_try __P((void));
static __inline void ipq_unlock __P((void));
static __inline int
ipq_lock_try()
{
int s;
/*
* Use splvm() -- we're blocking things that would cause
* mbuf allocation.
*/
s = splvm();
if (ipq_locked) {
splx(s);
return (0);
}
ipq_locked = 1;
splx(s);
return (1);
}
static __inline void
ipq_unlock()
{
int s;
s = splvm();
ipq_locked = 0;
splx(s);
}
#ifdef DIAGNOSTIC
#define IPQ_LOCK() \
do { \
if (ipq_lock_try() == 0) { \
printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \
panic("ipq_lock"); \
} \
} while (0)
#define IPQ_LOCK_CHECK() \
do { \
if (ipq_locked == 0) { \
printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \
panic("ipq lock check"); \
} \
} while (0)
#else
#define IPQ_LOCK() (void) ipq_lock_try()
#define IPQ_LOCK_CHECK() /* nothing */
#endif
#define IPQ_UNLOCK() ipq_unlock()
struct pool ipqent_pool;
#ifdef INET_CSUM_COUNTERS
#include <sys/device.h>
struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
NULL, "inet", "hwcsum bad");
struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
NULL, "inet", "hwcsum ok");
struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
NULL, "inet", "swcsum");
#define INET_CSUM_COUNTER_INCR(ev) (ev)->ev_count++
#else
#define INET_CSUM_COUNTER_INCR(ev) /* nothing */
#endif /* INET_CSUM_COUNTERS */
/*
* We need to save the IP options in case a protocol wants to respond
* to an incoming packet over the same route if the packet got here
* using IP source routing. This allows connection establishment and
* maintenance when the remote end is on a network that is not known
* to us.
*/
int ip_nhops = 0;
static struct ip_srcrt {
struct in_addr dst; /* final destination */
char nop; /* one NOP to align */
char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */
struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
} ip_srcrt;
static void save_rte __P((u_char *, struct in_addr));
/*
* IP initialization: fill in IP protocol switch table.
* All protocols not implemented in kernel go to raw IP protocol handler.
*/
void
ip_init()
{
struct protosw *pr;
int i;
pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl",
NULL);
pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
if (pr == 0)
panic("ip_init");
for (i = 0; i < IPPROTO_MAX; i++)
ip_protox[i] = pr - inetsw;
for (pr = inetdomain.dom_protosw;
pr < inetdomain.dom_protoswNPROTOSW; pr++)
if (pr->pr_domain->dom_family == PF_INET &&
pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
ip_protox[pr->pr_protocol] = pr - inetsw;
LIST_INIT(&ipq);
ip_id = time.tv_sec & 0xffff;
ipintrq.ifq_maxlen = ipqmaxlen;
TAILQ_INIT(&in_ifaddr);
in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR,
M_WAITOK, &in_ifaddrhash);
if (ip_mtudisc != 0)
ip_mtudisc_timeout_q =
rt_timer_queue_create(ip_mtudisc_timeout);
#ifdef GATEWAY
ipflow_init();
#endif
#ifdef PFIL_HOOKS
/* Register our Packet Filter hook. */
inet_pfil_hook.ph_type = PFIL_TYPE_AF;
inet_pfil_hook.ph_af = AF_INET;
i = pfil_head_register(&inet_pfil_hook);
if (i != 0)
printf("ip_init: WARNING: unable to register pfil hook, "
"error %d\n", i);
#endif /* PFIL_HOOKS */
#ifdef INET_CSUM_COUNTERS
evcnt_attach_static(&ip_hwcsum_bad);
evcnt_attach_static(&ip_hwcsum_ok);
evcnt_attach_static(&ip_swcsum);
#endif /* INET_CSUM_COUNTERS */
}
struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
struct route ipforward_rt;
/*
* IP software interrupt routine
*/
void
ipintr()
{
int s;
struct mbuf *m;
while (1) {
s = splnet();
IF_DEQUEUE(&ipintrq, m);
splx(s);
if (m == 0)
return;
ip_input(m);
}
}
/*
* Ip input routine. Checksum and byte swap header. If fragmented
* try to reassemble. Process options. Pass to next level.
*/
void
ip_input(struct mbuf *m)
{
struct ip *ip = NULL;
struct ipq *fp;
struct in_ifaddr *ia;
struct ifaddr *ifa;
struct ipqent *ipqe;
int hlen = 0, mff, len;
int downmatch;
#ifdef DIAGNOSTIC
if ((m->m_flags & M_PKTHDR) == 0)
panic("ipintr no HDR");
#endif
#ifdef IPSEC
/*
* should the inner packet be considered authentic?
* see comment in ah4_input().
*/
if (m) {
m->m_flags &= ~M_AUTHIPHDR;
m->m_flags &= ~M_AUTHIPDGM;
}
#endif
/*
* If no IP addresses have been set yet but the interfaces
* are receiving, can't do anything with incoming packets yet.
*/
if (TAILQ_FIRST(&in_ifaddr) == 0)
goto bad;
ipstat.ips_total++;
/*
* If the IP header is not aligned, slurp it up into a new
* mbuf with space for link headers, in the event we forward
* it. Otherwise, if it is aligned, make sure the entire
* base IP header is in the first mbuf of the chain.
*/
if (IP_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) {
if ((m = m_copyup(m, sizeof(struct ip),
(max_linkhdr + 3) & ~3)) == NULL) {
/* XXXJRT new stat, please */
ipstat.ips_toosmall++;
return;
}
} else if (__predict_false(m->m_len < sizeof (struct ip))) {
if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
ipstat.ips_toosmall++;
return;
}
}
ip = mtod(m, struct ip *);
if (ip->ip_v != IPVERSION) {
ipstat.ips_badvers++;
goto bad;
}
hlen = ip->ip_hl << 2;
if (hlen < sizeof(struct ip)) { /* minimum header length */
ipstat.ips_badhlen++;
goto bad;
}
if (hlen > m->m_len) {
if ((m = m_pullup(m, hlen)) == 0) {
ipstat.ips_badhlen++;
return;
}
ip = mtod(m, struct ip *);
}
/*
* RFC1122: packets with a multicast source address are
* not allowed.
*/
if (IN_MULTICAST(ip->ip_src.s_addr)) {
ipstat.ips_badaddr++;
goto bad;
}
/* 127/8 must not appear on wire - RFC1122 */
if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
(ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
ipstat.ips_badaddr++;
goto bad;
}
}
switch (m->m_pkthdr.csum_flags &
((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) |
M_CSUM_IPv4_BAD)) {
case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
goto badcsum;
case M_CSUM_IPv4:
/* Checksum was okay. */
INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
break;
default:
/* Must compute it ourselves. */
INET_CSUM_COUNTER_INCR(&ip_swcsum);
if (in_cksum(m, hlen) != 0)
goto bad;
break;
}
/* Retrieve the packet length. */
len = ntohs(ip->ip_len);
/*
* Check for additional length bogosity
*/
if (len < hlen) {
ipstat.ips_badlen++;
goto bad;
}
/*
* Check that the amount of data in the buffers
* is as at least much as the IP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
if (m->m_pkthdr.len < len) {
ipstat.ips_tooshort++;
goto bad;
}
if (m->m_pkthdr.len > len) {
if (m->m_len == m->m_pkthdr.len) {
m->m_len = len;
m->m_pkthdr.len = len;
} else
m_adj(m, len - m->m_pkthdr.len);
}
#ifdef IPSEC
/* ipflow (IP fast forwarding) is not compatible with IPsec. */
m->m_flags &= ~M_CANFASTFWD;
#else
/*
* Assume that we can create a fast-forward IP flow entry
* based on this packet.
*/
m->m_flags |= M_CANFASTFWD;
#endif
#ifdef PFIL_HOOKS
/*
* Run through list of hooks for input packets. If there are any
* filters which require that additional packets in the flow are
* not fast-forwarded, they must clear the M_CANFASTFWD flag.
* Note that filters must _never_ set this flag, as another filter
* in the list may have previously cleared it.
*/
/*
* let ipfilter look at packet on the wire,
* not the decapsulated packet.
*/
#ifdef IPSEC
if (!ipsec_getnhist(m))
#else
if (1)
#endif
{
if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif,
PFIL_IN) != 0)
return;
if (m == NULL)
return;
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
}
#endif /* PFIL_HOOKS */
#ifdef ALTQ
/* XXX Temporary until ALTQ is changed to use a pfil hook */
if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) {
/* packet dropped by traffic conditioner */
return;
}
#endif
/*
* Process options and, if not destined for us,
* ship it on. ip_dooptions returns 1 when an
* error was detected (causing an icmp message
* to be sent and the original packet to be freed).
*/
ip_nhops = 0; /* for source routed packets */
if (hlen > sizeof (struct ip) && ip_dooptions(m))
return;
/*
* Check our list of addresses, to see if the packet is for us.
*
* Traditional 4.4BSD did not consult IFF_UP at all.
* The behavior here is to treat addresses on !IFF_UP interface
* as not mine.
*/
downmatch = 0;
LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
if ((ia->ia_ifp->if_flags & IFF_UP) != 0)
break;
else
downmatch++;
}
}
if (ia != NULL)
goto ours;
if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
ia = ifatoia(ifa);
if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
/*
* Look for all-0's host part (old broadcast addr),
* either for subnet or net.
*/
ip->ip_dst.s_addr == ia->ia_subnet ||
ip->ip_dst.s_addr == ia->ia_net)
goto ours;
/*
* An interface with IP address zero accepts
* all packets that arrive on that interface.
*/
if (in_nullhost(ia->ia_addr.sin_addr))
goto ours;
}
}
if (IN_MULTICAST(ip->ip_dst.s_addr)) {
struct in_multi *inm;
#ifdef MROUTING
extern struct socket *ip_mrouter;
if (M_READONLY(m)) {
if ((m = m_pullup(m, hlen)) == 0) {
ipstat.ips_toosmall++;
return;
}
ip = mtod(m, struct ip *);
}
if (ip_mrouter) {
/*
* 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
* ip_mforward() returns a non-zero value, the packet
* must be discarded, else it may be accepted below.
*
* (The IP ident field is put in the same byte order
* as expected when ip_mforward() is called from
* ip_output().)
*/
if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
ipstat.ips_cantforward++;
m_freem(m);
return;
}
/*
* The process-level routing demon needs to receive
* all multicast IGMP packets, whether or not this
* host belongs to their destination groups.
*/
if (ip->ip_p == IPPROTO_IGMP)
goto ours;
ipstat.ips_forward++;
}
#endif
/*
* See if we belong to the destination multicast group on the
* arrival interface.
*/
IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
if (inm == NULL) {
ipstat.ips_cantforward++;
m_freem(m);
return;
}
goto ours;
}
if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
in_nullhost(ip->ip_dst))
goto ours;
/*
* Not for us; forward if possible and desirable.
*/
if (ipforwarding == 0) {
ipstat.ips_cantforward++;
m_freem(m);
} else {
/*
* If ip_dst matched any of my address on !IFF_UP interface,
* and there's no IFF_UP interface that matches ip_dst,
* send icmp unreach. Forwarding it will result in in-kernel
* forwarding loop till TTL goes to 0.
*/
if (downmatch) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
ipstat.ips_cantforward++;
return;
}
#ifdef IPSEC
if (ipsec4_in_reject(m, NULL)) {
ipsecstat.in_polvio++;
goto bad;
}
#endif
ip_forward(m, 0);
}
return;
ours:
/*
* If offset or IP_MF are set, must reassemble.
* Otherwise, nothing need be done.
* (We could look in the reassembly queue to see
* if the packet was previously fragmented,
* but it's not worth the time; just let them time out.)
*/
if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
if (M_READONLY(m)) {
if ((m = m_pullup(m, hlen)) == NULL) {
ipstat.ips_toosmall++;
goto bad;
}
ip = mtod(m, struct ip *);
}
/*
* Look for queue of fragments
* of this datagram.
*/
IPQ_LOCK();
LIST_FOREACH(fp, &ipq, ipq_q)
if (ip->ip_id == fp->ipq_id &&
in_hosteq(ip->ip_src, fp->ipq_src) &&
in_hosteq(ip->ip_dst, fp->ipq_dst) &&
ip->ip_p == fp->ipq_p)
goto found;
fp = 0;
found:
/*
* Adjust ip_len to not reflect header,
* set ipqe_mff if more fragments are expected,
* convert offset of this to bytes.
*/
ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
mff = (ip->ip_off & htons(IP_MF)) != 0;
if (mff) {
/*
* Make sure that fragments have a data length
* that's a non-zero multiple of 8 bytes.
*/
if (ntohs(ip->ip_len) == 0 ||
(ntohs(ip->ip_len) & 0x7) != 0) {
ipstat.ips_badfrags++;
IPQ_UNLOCK();
goto bad;
}
}
ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3);
/*
* If datagram marked as having more fragments
* or if this is not the first fragment,
* attempt reassembly; if it succeeds, proceed.
*/
if (mff || ip->ip_off != htons(0)) {
ipstat.ips_fragments++;
ipqe = pool_get(&ipqent_pool, PR_NOWAIT);
if (ipqe == NULL) {
ipstat.ips_rcvmemdrop++;
IPQ_UNLOCK();
goto bad;
}
ipqe->ipqe_mff = mff;
ipqe->ipqe_m = m;
ipqe->ipqe_ip = ip;
m = ip_reass(ipqe, fp);
if (m == 0) {
IPQ_UNLOCK();
return;
}
ipstat.ips_reassembled++;
ip = mtod(m, struct ip *);
hlen = ip->ip_hl << 2;
ip->ip_len = htons(ntohs(ip->ip_len) + hlen);
} else
if (fp)
ip_freef(fp);
IPQ_UNLOCK();
}
#ifdef IPSEC
/*
* enforce IPsec policy checking if we are seeing last header.
* note that we do not visit this with protocols with pcb layer
* code - like udp/tcp/raw ip.
*/
if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
ipsec4_in_reject(m, NULL)) {
ipsecstat.in_polvio++;
goto bad;
}
#endif
/*
* Switch out to protocol's input routine.
*/
#if IFA_STATS
if (ia && ip)
ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
#endif
ipstat.ips_delivered++;
{
int off = hlen, nh = ip->ip_p;
(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
return;
}
bad:
m_freem(m);
return;
badcsum:
ipstat.ips_badsum++;
m_freem(m);
}
/*
* Take incoming datagram fragment and try to
* reassemble it into whole datagram. If a chain for
* reassembly of this datagram already exists, then it
* is given as fp; otherwise have to make a chain.
*/
struct mbuf *
ip_reass(ipqe, fp)
struct ipqent *ipqe;
struct ipq *fp;
{
struct mbuf *m = ipqe->ipqe_m;
struct ipqent *nq, *p, *q;
struct ip *ip;
struct mbuf *t;
int hlen = ipqe->ipqe_ip->ip_hl << 2;
int i, next;
IPQ_LOCK_CHECK();
/*
* Presence of header sizes in mbufs
* would confuse code below.
*/
m->m_data += hlen;
m->m_len -= hlen;
/*
* If first fragment to arrive, create a reassembly queue.
*/
if (fp == 0) {
/*
* Enforce upper bound on number of fragmented packets
* for which we attempt reassembly;
* If maxfrag is 0, never accept fragments.
* If maxfrag is -1, accept all fragments without limitation.
*/
if (ip_maxfragpackets < 0)
;
else if (ip_nfragpackets >= ip_maxfragpackets)
goto dropfrag;
ip_nfragpackets++;
MALLOC(fp, struct ipq *, sizeof (struct ipq),
M_FTABLE, M_NOWAIT);
if (fp == NULL)
goto dropfrag;
LIST_INSERT_HEAD(&ipq, fp, ipq_q);
fp->ipq_ttl = IPFRAGTTL;
fp->ipq_p = ipqe->ipqe_ip->ip_p;
fp->ipq_id = ipqe->ipqe_ip->ip_id;
TAILQ_INIT(&fp->ipq_fragq);
fp->ipq_src = ipqe->ipqe_ip->ip_src;
fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
p = NULL;
goto insert;
}
/*
* Find a segment which begins after this one does.
*/
for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL;
p = q, q = TAILQ_NEXT(q, ipqe_q))
if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off))
break;
/*
* If there is a preceding segment, it may provide some of
* our data already. If so, drop the data from the incoming
* segment. If it provides all of our data, drop us.
*/
if (p != NULL) {
i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) -
ntohs(ipqe->ipqe_ip->ip_off);
if (i > 0) {
if (i >= ntohs(ipqe->ipqe_ip->ip_len))
goto dropfrag;
m_adj(ipqe->ipqe_m, i);
ipqe->ipqe_ip->ip_off =
htons(ntohs(ipqe->ipqe_ip->ip_off) + i);
ipqe->ipqe_ip->ip_len =
htons(ntohs(ipqe->ipqe_ip->ip_len) - i);
}
}
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
for (; q != NULL &&
ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) >
ntohs(q->ipqe_ip->ip_off); q = nq) {
i = (ntohs(ipqe->ipqe_ip->ip_off) +
ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off);
if (i < ntohs(q->ipqe_ip->ip_len)) {
q->ipqe_ip->ip_len =
htons(ntohs(q->ipqe_ip->ip_len) - i);
q->ipqe_ip->ip_off =
htons(ntohs(q->ipqe_ip->ip_off) + i);
m_adj(q->ipqe_m, i);
break;
}
nq = TAILQ_NEXT(q, ipqe_q);
m_freem(q->ipqe_m);
TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q);
pool_put(&ipqent_pool, q);
}
insert:
/*
* Stick new segment in its place;
* check for complete reassembly.
*/
if (p == NULL) {
TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
} else {
TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q);
}
next = 0;
for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL;
p = q, q = TAILQ_NEXT(q, ipqe_q)) {
if (ntohs(q->ipqe_ip->ip_off) != next)
return (0);
next += ntohs(q->ipqe_ip->ip_len);
}
if (p->ipqe_mff)
return (0);
/*
* Reassembly is complete. Check for a bogus message size and
* concatenate fragments.
*/
q = TAILQ_FIRST(&fp->ipq_fragq);
ip = q->ipqe_ip;
if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
ipstat.ips_toolong++;
ip_freef(fp);
return (0);
}
m = q->ipqe_m;
t = m->m_next;
m->m_next = 0;
m_cat(m, t);
nq = TAILQ_NEXT(q, ipqe_q);
pool_put(&ipqent_pool, q);
for (q = nq; q != NULL; q = nq) {
t = q->ipqe_m;
nq = TAILQ_NEXT(q, ipqe_q);
pool_put(&ipqent_pool, q);
m_cat(m, t);
}
/*
* Create header for new ip packet by
* modifying header of first packet;
* dequeue and discard fragment reassembly header.
* Make header visible.
*/
ip->ip_len = htons(next);
ip->ip_src = fp->ipq_src;
ip->ip_dst = fp->ipq_dst;
LIST_REMOVE(fp, ipq_q);
FREE(fp, M_FTABLE);
ip_nfragpackets--;
m->m_len += (ip->ip_hl << 2);
m->m_data -= (ip->ip_hl << 2);
/* some debugging cruft by sklower, below, will go away soon */
if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
int plen = 0;
for (t = m; t; t = t->m_next)
plen += t->m_len;
m->m_pkthdr.len = plen;
}
return (m);
dropfrag:
ipstat.ips_fragdropped++;
m_freem(m);
pool_put(&ipqent_pool, ipqe);
return (0);
}
/*
* Free a fragment reassembly header and all
* associated datagrams.
*/
void
ip_freef(fp)
struct ipq *fp;
{
struct ipqent *q, *p;
IPQ_LOCK_CHECK();
for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) {
p = TAILQ_NEXT(q, ipqe_q);
m_freem(q->ipqe_m);
TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q);
pool_put(&ipqent_pool, q);
}
LIST_REMOVE(fp, ipq_q);
FREE(fp, M_FTABLE);
ip_nfragpackets--;
}
/*
* IP timer processing;
* if a timer expires on a reassembly
* queue, discard it.
*/
void
ip_slowtimo()
{
struct ipq *fp, *nfp;
int s = splsoftnet();
IPQ_LOCK();
for (fp = LIST_FIRST(&ipq); fp != NULL; fp = nfp) {
nfp = LIST_NEXT(fp, ipq_q);
if (--fp->ipq_ttl == 0) {
ipstat.ips_fragtimeout++;
ip_freef(fp);
}
}
/*
* If we are over the maximum number of fragments
* (due to the limit being lowered), drain off
* enough to get down to the new limit.
*/
if (ip_maxfragpackets < 0)
;
else {
while (ip_nfragpackets > ip_maxfragpackets && LIST_FIRST(&ipq))
ip_freef(LIST_FIRST(&ipq));
}
IPQ_UNLOCK();
#ifdef GATEWAY
ipflow_slowtimo();
#endif
splx(s);
}
/*
* Drain off all datagram fragments.
*/
void
ip_drain()
{
/*
* We may be called from a device's interrupt context. If
* the ipq is already busy, just bail out now.
*/
if (ipq_lock_try() == 0)
return;
while (LIST_FIRST(&ipq) != NULL) {
ipstat.ips_fragdropped++;
ip_freef(LIST_FIRST(&ipq));
}
IPQ_UNLOCK();
}
/*
* Do option processing on a datagram,
* possibly discarding it if bad options are encountered,
* or forwarding it if source-routed.
* Returns 1 if packet has been forwarded/freed,
* 0 if the packet should be processed further.
*/
int
ip_dooptions(m)
struct mbuf *m;
{
struct ip *ip = mtod(m, struct ip *);
u_char *cp, *cp0;
struct ip_timestamp *ipt;
struct in_ifaddr *ia;
int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
struct in_addr dst;
n_time ntime;
dst = ip->ip_dst;
cp = (u_char *)(ip + 1);
cnt = (ip->ip_hl << 2) - sizeof (struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
else {
if (cnt < IPOPT_OLEN + sizeof(*cp)) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
optlen = cp[IPOPT_OLEN];
if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
}
switch (opt) {
default:
break;
/*
* Source routing with record.
* Find interface with current destination address.
* If none on this machine then drop if strictly routed,
* or do nothing if loosely routed.
* Record interface address and bring up next address
* component. If strictly routed make sure next
* address is on directly accessible net.
*/
case IPOPT_LSRR:
case IPOPT_SSRR:
if (ip_allowsrcrt == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_NET_PROHIB;
goto bad;
}
if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
ipaddr.sin_addr = ip->ip_dst;
ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
if (ia == 0) {
if (opt == IPOPT_SSRR) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
/*
* Loose routing, and not at next destination
* yet; nothing to do except forward.
*/
break;
}
off--; /* 0 origin */
if ((off + sizeof(struct in_addr)) > optlen) {
/*
* End of source route. Should be for us.
*/
save_rte(cp, ip->ip_src);
break;
}
/*
* locate outgoing interface
*/
bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
sizeof(ipaddr.sin_addr));
if (opt == IPOPT_SSRR)
ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
else
ia = ip_rtaddr(ipaddr.sin_addr);
if (ia == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
ip->ip_dst = ipaddr.sin_addr;
bcopy((caddr_t)&ia->ia_addr.sin_addr,
(caddr_t)(cp + off), sizeof(struct in_addr));
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
/*
* Let ip_intr's mcast routing check handle mcast pkts
*/
forward = !IN_MULTICAST(ip->ip_dst.s_addr);
break;
case IPOPT_RR:
if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
code = &cp[IPOPT_OLEN] - (u_char *)ip;
goto bad;
}
if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
code = &cp[IPOPT_OFFSET] - (u_char *)ip;
goto bad;
}
/*
* If no space remains, ignore.
*/
off--; /* 0 origin */
if ((off + sizeof(struct in_addr)) > optlen)
break;
bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
sizeof(ipaddr.sin_addr));
/*
* locate outgoing interface; if we're the destination,
* use the incoming interface (should be same).
*/
if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))))
== NULL &&
(ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
goto bad;
}
bcopy((caddr_t)&ia->ia_addr.sin_addr,
(caddr_t)(cp + off), sizeof(struct in_addr));
cp[IPOPT_OFFSET] += sizeof(struct in_addr);
break;
case IPOPT_TS:
code = cp - (u_char *)ip;
ipt = (struct ip_timestamp *)cp;
if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
code = (u_char *)&ipt->ipt_len - (u_char *)ip;
goto bad;
}
if (ipt->ipt_ptr < 5) {
code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
goto bad;
}
if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
if (++ipt->ipt_oflw == 0) {
code = (u_char *)&ipt->ipt_ptr -
(u_char *)ip;
goto bad;
}
break;
}
cp0 = (cp + ipt->ipt_ptr - 1);
switch (ipt->ipt_flg) {
case IPOPT_TS_TSONLY:
break;
case IPOPT_TS_TSANDADDR:
if (ipt->ipt_ptr - 1 + sizeof(n_time) +
sizeof(struct in_addr) > ipt->ipt_len) {
code = (u_char *)&ipt->ipt_ptr -
(u_char *)ip;
goto bad;
}
ipaddr.sin_addr = dst;
ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr),
m->m_pkthdr.rcvif));
if (ia == 0)
continue;
bcopy(&ia->ia_addr.sin_addr,
cp0, sizeof(struct in_addr));
ipt->ipt_ptr += sizeof(struct in_addr);
break;
case IPOPT_TS_PRESPEC:
if (ipt->ipt_ptr - 1 + sizeof(n_time) +
sizeof(struct in_addr) > ipt->ipt_len) {
code = (u_char *)&ipt->ipt_ptr -
(u_char *)ip;
goto bad;
}
bcopy(cp0, &ipaddr.sin_addr,
sizeof(struct in_addr));
if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))
== NULL)
continue;
ipt->ipt_ptr += sizeof(struct in_addr);
break;
default:
/* XXX can't take &ipt->ipt_flg */
code = (u_char *)&ipt->ipt_ptr -
(u_char *)ip + 1;
goto bad;
}
ntime = iptime();
cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1,
sizeof(n_time));
ipt->ipt_ptr += sizeof(n_time);
}
}
if (forward) {
if (ip_forwsrcrt == 0) {
type = ICMP_UNREACH;
code = ICMP_UNREACH_SRCFAIL;
goto bad;
}
ip_forward(m, 1);
return (1);
}
return (0);
bad:
icmp_error(m, type, code, 0, 0);
ipstat.ips_badoptions++;
return (1);
}
/*
* Given address of next destination (final or next hop),
* return internet address info of interface to be used to get there.
*/
struct in_ifaddr *
ip_rtaddr(dst)
struct in_addr dst;
{
struct sockaddr_in *sin;
sin = satosin(&ipforward_rt.ro_dst);
if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) {
if (ipforward_rt.ro_rt) {
RTFREE(ipforward_rt.ro_rt);
ipforward_rt.ro_rt = 0;
}
sin->sin_family = AF_INET;
sin->sin_len = sizeof(*sin);
sin->sin_addr = dst;
rtalloc(&ipforward_rt);
}
if (ipforward_rt.ro_rt == 0)
return ((struct in_ifaddr *)0);
return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
}
/*
* Save incoming source route for use in replies,
* to be picked up later by ip_srcroute if the receiver is interested.
*/
void
save_rte(option, dst)
u_char *option;
struct in_addr dst;
{
unsigned olen;
olen = option[IPOPT_OLEN];
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("save_rte: olen %d\n", olen);
#endif /* 0 */
if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
return;
bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
ip_srcrt.dst = dst;
}
/*
* Retrieve incoming source route for use in replies,
* in the same form used by setsockopt.
* The first hop is placed before the options, will be removed later.
*/
struct mbuf *
ip_srcroute()
{
struct in_addr *p, *q;
struct mbuf *m;
if (ip_nhops == 0)
return ((struct mbuf *)0);
m = m_get(M_DONTWAIT, MT_SOOPTS);
if (m == 0)
return ((struct mbuf *)0);
#define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
OPTSIZ;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
#endif
/*
* First save first hop for return route
*/
p = &ip_srcrt.route[ip_nhops - 1];
*(mtod(m, struct in_addr *)) = *p--;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
#endif
/*
* Copy option fields and padding (nop) to mbuf.
*/
ip_srcrt.nop = IPOPT_NOP;
ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
bcopy((caddr_t)&ip_srcrt.nop,
mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
q = (struct in_addr *)(mtod(m, caddr_t) +
sizeof(struct in_addr) + OPTSIZ);
#undef OPTSIZ
/*
* Record return path as an IP source route,
* reversing the path (pointers are now aligned).
*/
while (p >= ip_srcrt.route) {
#ifdef DIAGNOSTIC
if (ipprintfs)
printf(" %x", ntohl(q->s_addr));
#endif
*q++ = *p--;
}
/*
* Last hop goes to final destination.
*/
*q = ip_srcrt.dst;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf(" %x\n", ntohl(q->s_addr));
#endif
return (m);
}
/*
* Strip out IP options, at higher
* level protocol in the kernel.
* Second argument is buffer to which options
* will be moved, and return value is their length.
* XXX should be deleted; last arg currently ignored.
*/
void
ip_stripoptions(m, mopt)
struct mbuf *m;
struct mbuf *mopt;
{
int i;
struct ip *ip = mtod(m, struct ip *);
caddr_t opts;
int olen;
olen = (ip->ip_hl << 2) - sizeof (struct ip);
opts = (caddr_t)(ip + 1);
i = m->m_len - (sizeof (struct ip) + olen);
bcopy(opts + olen, opts, (unsigned)i);
m->m_len -= olen;
if (m->m_flags & M_PKTHDR)
m->m_pkthdr.len -= olen;
ip->ip_len = htons(ntohs(ip->ip_len) - olen);
ip->ip_hl = sizeof (struct ip) >> 2;
}
const int inetctlerrmap[PRC_NCMDS] = {
0, 0, 0, 0,
0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH,
EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
EMSGSIZE, EHOSTUNREACH, 0, 0,
0, 0, 0, 0,
ENOPROTOOPT
};
/*
* Forward a packet. If some error occurs return the sender
* an icmp packet. Note we can't always generate a meaningful
* icmp message because icmp doesn't have a large enough repertoire
* of codes and types.
*
* If not forwarding, just drop the packet. This could be confusing
* if ipforwarding was zero but some routing protocol was advancing
* us as a gateway to somewhere. However, we must let the routing
* protocol deal with that.
*
* The srcrt parameter indicates whether the packet is being forwarded
* via a source route.
*/
void
ip_forward(m, srcrt)
struct mbuf *m;
int srcrt;
{
struct ip *ip = mtod(m, struct ip *);
struct sockaddr_in *sin;
struct rtentry *rt;
int error, type = 0, code = 0;
struct mbuf *mcopy;
n_long dest;
struct ifnet *destifp;
#ifdef IPSEC
struct ifnet dummyifp;
#endif
/*
* Clear any in-bound checksum flags for this packet.
*/
m->m_pkthdr.csum_flags = 0;
dest = 0;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("forward: src %2.2x dst %2.2x ttl %x\n",
ntohl(ip->ip_src.s_addr),
ntohl(ip->ip_dst.s_addr), ip->ip_ttl);
#endif
if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
ipstat.ips_cantforward++;
m_freem(m);
return;
}
if (ip->ip_ttl <= IPTTLDEC) {
icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
return;
}
ip->ip_ttl -= IPTTLDEC;
sin = satosin(&ipforward_rt.ro_dst);
if ((rt = ipforward_rt.ro_rt) == 0 ||
!in_hosteq(ip->ip_dst, sin->sin_addr)) {
if (ipforward_rt.ro_rt) {
RTFREE(ipforward_rt.ro_rt);
ipforward_rt.ro_rt = 0;
}
sin->sin_family = AF_INET;
sin->sin_len = sizeof(struct sockaddr_in);
sin->sin_addr = ip->ip_dst;
rtalloc(&ipforward_rt);
if (ipforward_rt.ro_rt == 0) {
icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
return;
}
rt = ipforward_rt.ro_rt;
}
/*
* Save at most 68 bytes of the packet in case
* we need to generate an ICMP message to the src.
* Pullup to avoid sharing mbuf cluster between m and mcopy.
*/
mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
if (mcopy)
mcopy = m_pullup(mcopy, ip->ip_hl << 2);
/*
* If forwarding packet using same interface that it came in on,
* perhaps 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 default route
* or a route modified by a redirect.
*/
if (rt->rt_ifp == m->m_pkthdr.rcvif &&
(rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
!in_nullhost(satosin(rt_key(rt))->sin_addr) &&
ipsendredirects && !srcrt) {
if (rt->rt_ifa &&
(ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
ifatoia(rt->rt_ifa)->ia_subnet) {
if (rt->rt_flags & RTF_GATEWAY)
dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
else
dest = ip->ip_dst.s_addr;
/*
* Router requirements says to only send host
* redirects.
*/
type = ICMP_REDIRECT;
code = ICMP_REDIRECT_HOST;
#ifdef DIAGNOSTIC
if (ipprintfs)
printf("redirect (%d) to %x\n", code,
(u_int32_t)dest);
#endif
}
}
#ifdef IPSEC
/* Don't lookup socket in forwarding case */
(void)ipsec_setsocket(m, NULL);
#endif
error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
(IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
if (error)
ipstat.ips_cantforward++;
else {
ipstat.ips_forward++;
if (type)
ipstat.ips_redirectsent++;
else {
if (mcopy) {
#ifdef GATEWAY
if (mcopy->m_flags & M_CANFASTFWD)
ipflow_create(&ipforward_rt, mcopy);
#endif
m_freem(mcopy);
}
return;
}
}
if (mcopy == NULL)
return;
destifp = NULL;
switch (error) {
case 0: /* forwarded, but need redirect */
/* type, code set above */
break;
case ENETUNREACH: /* shouldn't happen, checked above */
case EHOSTUNREACH:
case ENETDOWN:
case EHOSTDOWN:
default:
type = ICMP_UNREACH;
code = ICMP_UNREACH_HOST;
break;
case EMSGSIZE:
type = ICMP_UNREACH;
code = ICMP_UNREACH_NEEDFRAG;
#ifndef IPSEC
if (ipforward_rt.ro_rt)
destifp = ipforward_rt.ro_rt->rt_ifp;
#else
/*
* If the packet is routed over IPsec tunnel, tell the
* originator the tunnel MTU.
* tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
* XXX quickhack!!!
*/
if (ipforward_rt.ro_rt) {
struct secpolicy *sp;
int ipsecerror;
size_t ipsechdr;
struct route *ro;
sp = ipsec4_getpolicybyaddr(mcopy,
IPSEC_DIR_OUTBOUND,
IP_FORWARDING,
&ipsecerror);
if (sp == NULL)
destifp = ipforward_rt.ro_rt->rt_ifp;
else {
/* count IPsec header size */
ipsechdr = ipsec4_hdrsiz(mcopy,
IPSEC_DIR_OUTBOUND,
NULL);
/*
* find the correct route for outer IPv4
* header, compute tunnel MTU.
*
* XXX BUG ALERT
* The "dummyifp" code relies upon the fact
* that icmp_error() touches only ifp->if_mtu.
*/
/*XXX*/
destifp = NULL;
if (sp->req != NULL
&& sp->req->sav != NULL
&& sp->req->sav->sah != NULL) {
ro = &sp->req->sav->sah->sa_route;
if (ro->ro_rt && ro->ro_rt->rt_ifp) {
dummyifp.if_mtu =
ro->ro_rt->rt_rmx.rmx_mtu ?
ro->ro_rt->rt_rmx.rmx_mtu :
ro->ro_rt->rt_ifp->if_mtu;
dummyifp.if_mtu -= ipsechdr;
destifp = &dummyifp;
}
}
key_freesp(sp);
}
}
#endif /*IPSEC*/
ipstat.ips_cantfrag++;
break;
case ENOBUFS:
#if 1
/*
* a router should not generate ICMP_SOURCEQUENCH as
* required in RFC1812 Requirements for IP Version 4 Routers.
* source quench could be a big problem under DoS attacks,
* or if the underlying interface is rate-limited.
*/
if (mcopy)
m_freem(mcopy);
return;
#else
type = ICMP_SOURCEQUENCH;
code = 0;
break;
#endif
}
icmp_error(mcopy, type, code, dest, destifp);
}
void
ip_savecontrol(inp, mp, ip, m)
struct inpcb *inp;
struct mbuf **mp;
struct ip *ip;
struct mbuf *m;
{
if (inp->inp_socket->so_options & SO_TIMESTAMP) {
struct timeval tv;
microtime(&tv);
*mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
SCM_TIMESTAMP, SOL_SOCKET);
if (*mp)
mp = &(*mp)->m_next;
}
if (inp->inp_flags & INP_RECVDSTADDR) {
*mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#ifdef notyet
/*
* XXX
* Moving these out of udp_input() made them even more broken
* than they already were.
* - fenner@parc.xerox.com
*/
/* options were tossed already */
if (inp->inp_flags & INP_RECVOPTS) {
*mp = sbcreatecontrol((caddr_t) opts_deleted_above,
sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
/* ip_srcroute doesn't do what we want here, need to fix */
if (inp->inp_flags & INP_RECVRETOPTS) {
*mp = sbcreatecontrol((caddr_t) ip_srcroute(),
sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
#endif
if (inp->inp_flags & INP_RECVIF) {
struct sockaddr_dl sdl;
sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]);
sdl.sdl_family = AF_LINK;
sdl.sdl_index = m->m_pkthdr.rcvif ?
m->m_pkthdr.rcvif->if_index : 0;
sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0;
*mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len,
IP_RECVIF, IPPROTO_IP);
if (*mp)
mp = &(*mp)->m_next;
}
}
int
ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
int *name;
u_int namelen;
void *oldp;
size_t *oldlenp;
void *newp;
size_t newlen;
{
extern int subnetsarelocal, hostzeroisbroadcast;
int error, old;
/* All sysctl names at this level are terminal. */
if (namelen != 1)
return (ENOTDIR);
switch (name[0]) {
case IPCTL_FORWARDING:
return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
case IPCTL_SENDREDIRECTS:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ipsendredirects));
case IPCTL_DEFTTL:
return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
#ifdef notyet
case IPCTL_DEFMTU:
return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
#endif
case IPCTL_FORWSRCRT:
/* Don't allow this to change in a secure environment. */
if (securelevel > 0)
return (sysctl_rdint(oldp, oldlenp, newp,
ip_forwsrcrt));
else
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ip_forwsrcrt));
case IPCTL_DIRECTEDBCAST:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ip_directedbcast));
case IPCTL_ALLOWSRCRT:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ip_allowsrcrt));
case IPCTL_SUBNETSARELOCAL:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&subnetsarelocal));
case IPCTL_MTUDISC:
error = sysctl_int(oldp, oldlenp, newp, newlen,
&ip_mtudisc);
if (ip_mtudisc != 0 && ip_mtudisc_timeout_q == NULL) {
ip_mtudisc_timeout_q =
rt_timer_queue_create(ip_mtudisc_timeout);
} else if (ip_mtudisc == 0 && ip_mtudisc_timeout_q != NULL) {
rt_timer_queue_destroy(ip_mtudisc_timeout_q, TRUE);
ip_mtudisc_timeout_q = NULL;
}
return error;
case IPCTL_ANONPORTMIN:
old = anonportmin;
error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin);
if (anonportmin >= anonportmax || anonportmin < 0
|| anonportmin > 65535
#ifndef IPNOPRIVPORTS
|| anonportmin < IPPORT_RESERVED
#endif
) {
anonportmin = old;
return (EINVAL);
}
return (error);
case IPCTL_ANONPORTMAX:
old = anonportmax;
error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax);
if (anonportmin >= anonportmax || anonportmax < 0
|| anonportmax > 65535
#ifndef IPNOPRIVPORTS
|| anonportmax < IPPORT_RESERVED
#endif
) {
anonportmax = old;
return (EINVAL);
}
return (error);
case IPCTL_MTUDISCTIMEOUT:
old = ip_mtudisc_timeout;
error = sysctl_int(oldp, oldlenp, newp, newlen,
&ip_mtudisc_timeout);
if (ip_mtudisc_timeout < 0) {
ip_mtudisc_timeout = old;
return (EINVAL);
}
if (ip_mtudisc_timeout_q != NULL)
rt_timer_queue_change(ip_mtudisc_timeout_q,
ip_mtudisc_timeout);
return (error);
#ifdef GATEWAY
case IPCTL_MAXFLOWS:
{
int s;
error = sysctl_int(oldp, oldlenp, newp, newlen,
&ip_maxflows);
s = splsoftnet();
ipflow_reap(0);
splx(s);
return (error);
}
#endif
case IPCTL_HOSTZEROBROADCAST:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&hostzeroisbroadcast));
#if NGIF > 0
case IPCTL_GIF_TTL:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ip_gif_ttl));
#endif
#if NGRE > 0
case IPCTL_GRE_TTL:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ip_gre_ttl));
#endif
#ifndef IPNOPRIVPORTS
case IPCTL_LOWPORTMIN:
old = lowportmin;
error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmin);
if (lowportmin >= lowportmax
|| lowportmin > IPPORT_RESERVEDMAX
|| lowportmin < IPPORT_RESERVEDMIN
) {
lowportmin = old;
return (EINVAL);
}
return (error);
case IPCTL_LOWPORTMAX:
old = lowportmax;
error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmax);
if (lowportmin >= lowportmax
|| lowportmax > IPPORT_RESERVEDMAX
|| lowportmax < IPPORT_RESERVEDMIN
) {
lowportmax = old;
return (EINVAL);
}
return (error);
#endif
case IPCTL_MAXFRAGPACKETS:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&ip_maxfragpackets));
default:
return (EOPNOTSUPP);
}
/* NOTREACHED */
}
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