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NetBSD/sys/netinet/ip_icmp.c

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/* $NetBSD: ip_icmp.c,v 1.96 2005/10/23 18:38:53 christos 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, 2000 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.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of Zembu Labs, Inc.
*
* 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. 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_icmp.c 8.2 (Berkeley) 1/4/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip_icmp.c,v 1.96 2005/10/23 18:38:53 christos Exp $");
#include "opt_ipsec.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_var.h>
#include <netinet/in_pcb.h>
#include <netinet/in_proto.h>
#include <netinet/icmp_var.h>
#ifdef IPSEC
#include <netinet6/ipsec.h>
#include <netkey/key.h>
#endif
#ifdef FAST_IPSEC
#include <netipsec/ipsec.h>
#include <netipsec/key.h>
#endif /* FAST_IPSEC*/
#include <machine/stdarg.h>
/*
* ICMP routines: error generation, receive packet processing, and
* routines to turnaround packets back to the originator, and
* host table maintenance routines.
*/
int icmpmaskrepl = 0;
#ifdef ICMPPRINTFS
int icmpprintfs = 0;
#endif
int icmpreturndatabytes = 8;
struct icmpstat icmpstat;
/*
* List of callbacks to notify when Path MTU changes are made.
*/
struct icmp_mtudisc_callback {
LIST_ENTRY(icmp_mtudisc_callback) mc_list;
void (*mc_func)(struct in_addr);
};
LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks =
LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks);
#if 0
static int ip_next_mtu(int, int);
#else
/*static*/ int ip_next_mtu(int, int);
#endif
extern int icmperrppslim;
static int icmperrpps_count = 0;
static struct timeval icmperrppslim_last;
static int icmp_rediraccept = 1;
static int icmp_redirtimeout = 600;
static struct rttimer_queue *icmp_redirect_timeout_q = NULL;
static void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *);
static void icmp_redirect_timeout(struct rtentry *, struct rttimer *);
static int icmp_ratelimit(const struct in_addr *, const int, const int);
void
icmp_init(void)
{
/*
* This is only useful if the user initializes redirtimeout to
* something other than zero.
*/
if (icmp_redirtimeout != 0) {
icmp_redirect_timeout_q =
rt_timer_queue_create(icmp_redirtimeout);
}
}
/*
* Register a Path MTU Discovery callback.
*/
void
icmp_mtudisc_callback_register(void (*func)(struct in_addr))
{
struct icmp_mtudisc_callback *mc;
for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL;
mc = LIST_NEXT(mc, mc_list)) {
if (mc->mc_func == func)
return;
}
mc = malloc(sizeof(*mc), M_PCB, M_NOWAIT);
if (mc == NULL)
panic("icmp_mtudisc_callback_register");
mc->mc_func = func;
LIST_INSERT_HEAD(&icmp_mtudisc_callbacks, mc, mc_list);
}
/*
* Generate an error packet of type error
* in response to bad packet ip.
*/
void
icmp_error(struct mbuf *n, int type, int code, n_long dest,
int destmtu)
{
struct ip *oip = mtod(n, struct ip *), *nip;
unsigned oiplen = oip->ip_hl << 2;
struct icmp *icp;
struct mbuf *m;
unsigned icmplen, mblen;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_error(%p, type:%d, code:%d)\n", oip, type,
code);
#endif
if (type != ICMP_REDIRECT)
icmpstat.icps_error++;
/*
* Don't send error if the original packet was encrypted.
* Don't send error if not the first fragment of message.
* Don't error if the old packet protocol was ICMP
* error message, only known informational types.
*/
if (n->m_flags & M_DECRYPTED)
goto freeit;
if (oip->ip_off &~ htons(IP_MF|IP_DF))
goto freeit;
if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
n->m_len >= oiplen + ICMP_MINLEN &&
!ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) {
icmpstat.icps_oldicmp++;
goto freeit;
}
/* Don't send error in response to a multicast or broadcast packet */
if (n->m_flags & (M_BCAST|M_MCAST))
goto freeit;
/*
* First, do a rate limitation check.
*/
if (icmp_ratelimit(&oip->ip_src, type, code)) {
/* XXX stat */
goto freeit;
}
/*
* Now, formulate icmp message
*/
icmplen = oiplen + min(icmpreturndatabytes,
ntohs(oip->ip_len) - oiplen);
/*
* Defend against mbuf chains shorter than oip->ip_len - oiplen:
*/
mblen = 0;
for (m = n; m && (mblen < icmplen); m = m->m_next)
mblen += m->m_len;
icmplen = min(mblen, icmplen);
/*
* As we are not required to return everything we have,
* we return whatever we can return at ease.
*
* Note that ICMP datagrams longer than 576 octets are out of spec
* according to RFC1812; the limit on icmpreturndatabytes below in
* icmp_sysctl will keep things below that limit.
*/
KASSERT(ICMP_MINLEN <= MCLBYTES);
if (icmplen + ICMP_MINLEN > MCLBYTES)
icmplen = MCLBYTES - ICMP_MINLEN;
m = m_gethdr(M_DONTWAIT, MT_HEADER);
if (m && (icmplen + ICMP_MINLEN > MHLEN)) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_freem(m);
m = NULL;
}
}
if (m == NULL)
goto freeit;
MCLAIM(m, n->m_owner);
m->m_len = icmplen + ICMP_MINLEN;
if ((m->m_flags & M_EXT) == 0)
MH_ALIGN(m, m->m_len);
icp = mtod(m, struct icmp *);
if ((u_int)type > ICMP_MAXTYPE)
panic("icmp_error");
icmpstat.icps_outhist[type]++;
icp->icmp_type = type;
if (type == ICMP_REDIRECT)
icp->icmp_gwaddr.s_addr = dest;
else {
icp->icmp_void = 0;
/*
* The following assignments assume an overlay with the
* zeroed icmp_void field.
*/
if (type == ICMP_PARAMPROB) {
icp->icmp_pptr = code;
code = 0;
} else if (type == ICMP_UNREACH &&
code == ICMP_UNREACH_NEEDFRAG && destmtu)
icp->icmp_nextmtu = htons(destmtu);
}
icp->icmp_code = code;
m_copydata(n, 0, icmplen, (caddr_t)&icp->icmp_ip);
nip = &icp->icmp_ip;
/*
* Now, copy old ip header (without options)
* in front of icmp message.
*/
if (m->m_data - sizeof(struct ip) < m->m_pktdat)
panic("icmp len");
m->m_data -= sizeof(struct ip);
m->m_len += sizeof(struct ip);
m->m_pkthdr.len = m->m_len;
m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
nip = mtod(m, struct ip *);
/* ip_v set in ip_output */
nip->ip_hl = sizeof(struct ip) >> 2;
nip->ip_tos = 0;
nip->ip_len = htons(m->m_len);
/* ip_id set in ip_output */
nip->ip_off = htons(0);
/* ip_ttl set in icmp_reflect */
nip->ip_p = IPPROTO_ICMP;
nip->ip_src = oip->ip_src;
nip->ip_dst = oip->ip_dst;
icmp_reflect(m);
freeit:
m_freem(n);
}
struct sockaddr_in icmpsrc = { sizeof (struct sockaddr_in), AF_INET };
static struct sockaddr_in icmpdst = { sizeof (struct sockaddr_in), AF_INET };
static struct sockaddr_in icmpgw = { sizeof (struct sockaddr_in), AF_INET };
struct sockaddr_in icmpmask = { 8, 0 };
/*
* Process a received ICMP message.
*/
void
icmp_input(struct mbuf *m, ...)
{
int proto;
struct icmp *icp;
struct ip *ip = mtod(m, struct ip *);
int icmplen;
int i;
struct in_ifaddr *ia;
void *(*ctlfunc)(int, struct sockaddr *, void *);
int code;
int hlen;
va_list ap;
struct rtentry *rt;
va_start(ap, m);
hlen = va_arg(ap, int);
proto = va_arg(ap, int);
va_end(ap);
/*
* Locate icmp structure in mbuf, and check
* that not corrupted and of at least minimum length.
*/
icmplen = ntohs(ip->ip_len) - hlen;
#ifdef ICMPPRINTFS
if (icmpprintfs) {
printf("icmp_input from `%s' to ", inet_ntoa(ip->ip_src));
printf("`%s', len %d\n", inet_ntoa(ip->ip_dst), icmplen);
}
#endif
if (icmplen < ICMP_MINLEN) {
icmpstat.icps_tooshort++;
goto freeit;
}
i = hlen + min(icmplen, ICMP_ADVLENMIN);
if (m->m_len < i && (m = m_pullup(m, i)) == 0) {
icmpstat.icps_tooshort++;
return;
}
ip = mtod(m, struct ip *);
m->m_len -= hlen;
m->m_data += hlen;
icp = mtod(m, struct icmp *);
/* Don't need to assert alignment, here. */
if (in_cksum(m, icmplen)) {
icmpstat.icps_checksum++;
goto freeit;
}
m->m_len += hlen;
m->m_data -= hlen;
#ifdef ICMPPRINTFS
/*
* Message type specific processing.
*/
if (icmpprintfs)
printf("icmp_input(type:%d, code:%d)\n", icp->icmp_type,
icp->icmp_code);
#endif
if (icp->icmp_type > ICMP_MAXTYPE)
goto raw;
icmpstat.icps_inhist[icp->icmp_type]++;
code = icp->icmp_code;
switch (icp->icmp_type) {
case ICMP_UNREACH:
switch (code) {
case ICMP_UNREACH_NET:
case ICMP_UNREACH_HOST:
case ICMP_UNREACH_PROTOCOL:
case ICMP_UNREACH_PORT:
case ICMP_UNREACH_SRCFAIL:
code += PRC_UNREACH_NET;
break;
case ICMP_UNREACH_NEEDFRAG:
code = PRC_MSGSIZE;
break;
case ICMP_UNREACH_NET_UNKNOWN:
case ICMP_UNREACH_NET_PROHIB:
case ICMP_UNREACH_TOSNET:
code = PRC_UNREACH_NET;
break;
case ICMP_UNREACH_HOST_UNKNOWN:
case ICMP_UNREACH_ISOLATED:
case ICMP_UNREACH_HOST_PROHIB:
case ICMP_UNREACH_TOSHOST:
code = PRC_UNREACH_HOST;
break;
default:
goto badcode;
}
goto deliver;
case ICMP_TIMXCEED:
if (code > 1)
goto badcode;
code += PRC_TIMXCEED_INTRANS;
goto deliver;
case ICMP_PARAMPROB:
if (code > 1)
goto badcode;
code = PRC_PARAMPROB;
goto deliver;
case ICMP_SOURCEQUENCH:
if (code)
goto badcode;
code = PRC_QUENCH;
goto deliver;
deliver:
/*
* Problem with datagram; advise higher level routines.
*/
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
icmpstat.icps_badlen++;
goto freeit;
}
if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr))
goto badcode;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
#endif
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
if (ctlfunc)
(void) (*ctlfunc)(code, sintosa(&icmpsrc),
&icp->icmp_ip);
break;
badcode:
icmpstat.icps_badcode++;
break;
case ICMP_ECHO:
icp->icmp_type = ICMP_ECHOREPLY;
goto reflect;
case ICMP_TSTAMP:
if (icmplen < ICMP_TSLEN) {
icmpstat.icps_badlen++;
break;
}
icp->icmp_type = ICMP_TSTAMPREPLY;
icp->icmp_rtime = iptime();
icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */
goto reflect;
case ICMP_MASKREQ:
if (icmpmaskrepl == 0)
break;
/*
* We are not able to respond with all ones broadcast
* unless we receive it over a point-to-point interface.
*/
if (icmplen < ICMP_MASKLEN) {
icmpstat.icps_badlen++;
break;
}
if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
in_nullhost(ip->ip_dst))
icmpdst.sin_addr = ip->ip_src;
else
icmpdst.sin_addr = ip->ip_dst;
ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst),
m->m_pkthdr.rcvif));
if (ia == 0)
break;
icp->icmp_type = ICMP_MASKREPLY;
icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr;
if (in_nullhost(ip->ip_src)) {
if (ia->ia_ifp->if_flags & IFF_BROADCAST)
ip->ip_src = ia->ia_broadaddr.sin_addr;
else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
ip->ip_src = ia->ia_dstaddr.sin_addr;
}
reflect:
icmpstat.icps_reflect++;
icmpstat.icps_outhist[icp->icmp_type]++;
icmp_reflect(m);
return;
case ICMP_REDIRECT:
if (code > 3)
goto badcode;
if (icmp_rediraccept == 0)
goto freeit;
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) ||
icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) {
icmpstat.icps_badlen++;
break;
}
/*
* Short circuit routing redirects to force
* immediate change in the kernel's routing
* tables. The message is also handed to anyone
* listening on a raw socket (e.g. the routing
* daemon for use in updating its tables).
*/
icmpgw.sin_addr = ip->ip_src;
icmpdst.sin_addr = icp->icmp_gwaddr;
#ifdef ICMPPRINTFS
if (icmpprintfs) {
printf("redirect dst `%s' to ", inet_ntoa(icp->icmp_ip.ip_dst));
printf("`%s'\n", inet_ntoa(icp->icmp_gwaddr));
}
#endif
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
rt = NULL;
rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst),
(struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
sintosa(&icmpgw), (struct rtentry **)&rt);
if (rt != NULL && icmp_redirtimeout != 0) {
i = rt_timer_add(rt, icmp_redirect_timeout,
icmp_redirect_timeout_q);
if (i)
log(LOG_ERR, "ICMP: redirect failed to "
"register timeout for route to %x, "
"code %d\n",
icp->icmp_ip.ip_dst.s_addr, i);
}
if (rt != NULL)
rtfree(rt);
pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc));
#if defined(IPSEC) || defined(FAST_IPSEC)
key_sa_routechange((struct sockaddr *)&icmpsrc);
#endif
break;
/*
* No kernel processing for the following;
* just fall through to send to raw listener.
*/
case ICMP_ECHOREPLY:
case ICMP_ROUTERADVERT:
case ICMP_ROUTERSOLICIT:
case ICMP_TSTAMPREPLY:
case ICMP_IREQREPLY:
case ICMP_MASKREPLY:
default:
break;
}
raw:
rip_input(m, hlen, proto);
return;
freeit:
m_freem(m);
return;
}
/*
* Reflect the ip packet back to the source
*/
void
icmp_reflect(struct mbuf *m)
{
struct ip *ip = mtod(m, struct ip *);
struct in_ifaddr *ia;
struct ifaddr *ifa;
struct sockaddr_in *sin = 0;
struct in_addr t;
struct mbuf *opts = 0;
int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
if (!in_canforward(ip->ip_src) &&
((ip->ip_src.s_addr & IN_CLASSA_NET) !=
htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) {
m_freem(m); /* Bad return address */
goto done; /* ip_output() will check for broadcast */
}
t = ip->ip_dst;
ip->ip_dst = ip->ip_src;
/*
* If the incoming packet was addressed directly to us, use
* dst as the src for the reply. Otherwise (broadcast or
* anonymous), use an address which corresponds to the
* incoming interface, with a preference for the address which
* corresponds to the route to the destination of the ICMP.
*/
/* Look for packet addressed to us */
INADDR_TO_IA(t, ia);
/* look for packet sent to broadcast address */
if (ia == NULL && m->m_pkthdr.rcvif &&
(m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST)) {
IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) {
ia = ifatoia(ifa);
break;
}
}
}
if (ia)
sin = &ia->ia_addr;
icmpdst.sin_addr = t;
/*
* if the packet is addressed somewhere else, compute the
* source address for packets routed back to the source, and
* use that, if it's an address on the interface which
* received the packet
*/
if (sin == (struct sockaddr_in *)0 && m->m_pkthdr.rcvif) {
struct sockaddr_in sin_dst;
struct route icmproute;
int errornum;
sin_dst.sin_family = AF_INET;
sin_dst.sin_len = sizeof(struct sockaddr_in);
sin_dst.sin_addr = ip->ip_dst;
bzero(&icmproute, sizeof(icmproute));
errornum = 0;
sin = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum);
/* errornum is never used */
if (icmproute.ro_rt)
RTFREE(icmproute.ro_rt);
/* check to make sure sin is a source address on rcvif */
if (sin) {
t = sin->sin_addr;
sin = (struct sockaddr_in *)0;
INADDR_TO_IA(t, ia);
while (ia) {
if (ia->ia_ifp == m->m_pkthdr.rcvif) {
sin = &ia->ia_addr;
break;
}
NEXT_IA_WITH_SAME_ADDR(ia);
}
}
}
/*
* if it was not addressed to us, but the route doesn't go out
* the source interface, pick an address on the source
* interface. This can happen when routing is asymmetric, or
* when the incoming packet was encapsulated
*/
if (sin == (struct sockaddr_in *)0 && m->m_pkthdr.rcvif) {
IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) {
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
sin = &(ifatoia(ifa)->ia_addr);
break;
}
}
/*
* The following happens if the packet was not addressed to us,
* and was received on an interface with no IP address:
* We find the first AF_INET address on the first non-loopback
* interface.
*/
if (sin == (struct sockaddr_in *)0)
TAILQ_FOREACH(ia, &in_ifaddrhead, ia_list) {
if (ia->ia_ifp->if_flags & IFF_LOOPBACK)
continue;
sin = &ia->ia_addr;
break;
}
/*
* If we still didn't find an address, punt. We could have an
* interface up (and receiving packets) with no address.
*/
if (sin == (struct sockaddr_in *)0) {
m_freem(m);
goto done;
}
ip->ip_src = sin->sin_addr;
ip->ip_ttl = MAXTTL;
if (optlen > 0) {
u_char *cp;
int opt, cnt;
u_int len;
/*
* Retrieve any source routing from the incoming packet;
* add on any record-route or timestamp options.
*/
cp = (u_char *) (ip + 1);
if ((opts = ip_srcroute()) == 0 &&
(opts = m_gethdr(M_DONTWAIT, MT_HEADER))) {
MCLAIM(opts, m->m_owner);
opts->m_len = sizeof(struct in_addr);
*mtod(opts, struct in_addr *) = zeroin_addr;
}
if (opts) {
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_reflect optlen %d rt %d => ",
optlen, opts->m_len);
#endif
for (cnt = optlen; cnt > 0; cnt -= len, cp += len) {
opt = cp[IPOPT_OPTVAL];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
len = 1;
else {
if (cnt < IPOPT_OLEN + sizeof(*cp))
break;
len = cp[IPOPT_OLEN];
if (len < IPOPT_OLEN + sizeof(*cp) ||
len > cnt)
break;
}
/*
* Should check for overflow, but it "can't happen"
*/
if (opt == IPOPT_RR || opt == IPOPT_TS ||
opt == IPOPT_SECURITY) {
bcopy((caddr_t)cp,
mtod(opts, caddr_t) + opts->m_len, len);
opts->m_len += len;
}
}
/* Terminate & pad, if necessary */
if ((cnt = opts->m_len % 4) != 0) {
for (; cnt < 4; cnt++) {
*(mtod(opts, caddr_t) + opts->m_len) =
IPOPT_EOL;
opts->m_len++;
}
}
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("%d\n", opts->m_len);
#endif
}
/*
* Now strip out original options by copying rest of first
* mbuf's data back, and adjust the IP length.
*/
ip->ip_len = htons(ntohs(ip->ip_len) - optlen);
ip->ip_hl = sizeof(struct ip) >> 2;
m->m_len -= optlen;
if (m->m_flags & M_PKTHDR)
m->m_pkthdr.len -= optlen;
optlen += sizeof(struct ip);
bcopy((caddr_t)ip + optlen, (caddr_t)(ip + 1),
(unsigned)(m->m_len - sizeof(struct ip)));
}
m_tag_delete_nonpersistent(m);
m->m_flags &= ~(M_BCAST|M_MCAST);
/*
* Clear any in-bound checksum flags for this packet.
*/
if (m->m_flags & M_PKTHDR)
m->m_pkthdr.csum_flags = 0;
icmp_send(m, opts);
done:
if (opts)
(void)m_free(opts);
}
/*
* Send an icmp packet back to the ip level,
* after supplying a checksum.
*/
void
icmp_send(struct mbuf *m, struct mbuf *opts)
{
struct ip *ip = mtod(m, struct ip *);
int hlen;
struct icmp *icp;
hlen = ip->ip_hl << 2;
m->m_data += hlen;
m->m_len -= hlen;
icp = mtod(m, struct icmp *);
icp->icmp_cksum = 0;
icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen);
m->m_data -= hlen;
m->m_len += hlen;
#ifdef ICMPPRINTFS
if (icmpprintfs) {
printf("icmp_send to destination `%s' from ", inet_ntoa(ip->ip_dst));
printf("`%s'\n", inet_ntoa(ip->ip_src));
}
#endif
(void) ip_output(m, opts, NULL, 0,
(struct ip_moptions *)NULL, (struct socket *)NULL);
}
n_time
iptime(void)
{
struct timeval atv;
u_long t;
microtime(&atv);
t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
return (htonl(t));
}
/*
* sysctl helper routine for net.inet.icmp.returndatabytes. ensures
* that the new value is in the correct range.
*/
static int
sysctl_net_inet_icmp_returndatabytes(SYSCTLFN_ARGS)
{
int error, t;
struct sysctlnode node;
node = *rnode;
node.sysctl_data = &t;
t = icmpreturndatabytes;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return (error);
if (t < 8 || t > 512)
return (EINVAL);
icmpreturndatabytes = t;
return (0);
}
/*
* sysctl helper routine for net.inet.icmp.redirtimeout. ensures that
* the given value is not less than zero and then resets the timeout
* queue.
*/
static int
sysctl_net_inet_icmp_redirtimeout(SYSCTLFN_ARGS)
{
int error, tmp;
struct sysctlnode node;
node = *rnode;
node.sysctl_data = &tmp;
tmp = icmp_redirtimeout;
error = sysctl_lookup(SYSCTLFN_CALL(&node));
if (error || newp == NULL)
return (error);
if (tmp < 0)
return (EINVAL);
icmp_redirtimeout = tmp;
/*
* was it a *defined* side-effect that anyone even *reading*
* this value causes these things to happen?
*/
if (icmp_redirect_timeout_q != NULL) {
if (icmp_redirtimeout == 0) {
rt_timer_queue_destroy(icmp_redirect_timeout_q,
TRUE);
icmp_redirect_timeout_q = NULL;
} else {
rt_timer_queue_change(icmp_redirect_timeout_q,
icmp_redirtimeout);
}
} else if (icmp_redirtimeout > 0) {
icmp_redirect_timeout_q =
rt_timer_queue_create(icmp_redirtimeout);
}
return (0);
}
SYSCTL_SETUP(sysctl_net_inet_icmp_setup, "sysctl net.inet.icmp subtree setup")
{
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "net", NULL,
NULL, 0, NULL, 0,
CTL_NET, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "inet", NULL,
NULL, 0, NULL, 0,
CTL_NET, PF_INET, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_NODE, "icmp",
SYSCTL_DESCR("ICMPv4 related settings"),
NULL, 0, NULL, 0,
CTL_NET, PF_INET, IPPROTO_ICMP, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "maskrepl",
SYSCTL_DESCR("Respond to ICMP_MASKREQ messages"),
NULL, 0, &icmpmaskrepl, 0,
CTL_NET, PF_INET, IPPROTO_ICMP,
ICMPCTL_MASKREPL, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "returndatabytes",
SYSCTL_DESCR("Number of bytes to return in an ICMP "
"error message"),
sysctl_net_inet_icmp_returndatabytes, 0,
&icmpreturndatabytes, 0,
CTL_NET, PF_INET, IPPROTO_ICMP,
ICMPCTL_RETURNDATABYTES, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "errppslimit",
SYSCTL_DESCR("Maximum number of outgoing ICMP error "
"messages per second"),
NULL, 0, &icmperrppslim, 0,
CTL_NET, PF_INET, IPPROTO_ICMP,
ICMPCTL_ERRPPSLIMIT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "rediraccept",
SYSCTL_DESCR("Accept ICMP_REDIRECT messages"),
NULL, 0, &icmp_rediraccept, 0,
CTL_NET, PF_INET, IPPROTO_ICMP,
ICMPCTL_REDIRACCEPT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
CTLTYPE_INT, "redirtimeout",
SYSCTL_DESCR("Lifetime of ICMP_REDIRECT generated "
"routes"),
sysctl_net_inet_icmp_redirtimeout, 0,
&icmp_redirtimeout, 0,
CTL_NET, PF_INET, IPPROTO_ICMP,
ICMPCTL_REDIRTIMEOUT, CTL_EOL);
sysctl_createv(clog, 0, NULL, NULL,
CTLFLAG_PERMANENT,
CTLTYPE_STRUCT, "stats",
SYSCTL_DESCR("ICMP statistics"),
NULL, 0, &icmpstat, sizeof(icmpstat),
CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_STATS,
CTL_EOL);
}
/* Table of common MTUs: */
static const u_int mtu_table[] = {
65535, 65280, 32000, 17914, 9180, 8166,
4352, 2002, 1492, 1006, 508, 296, 68, 0
};
void
icmp_mtudisc(struct icmp *icp, struct in_addr faddr)
{
struct icmp_mtudisc_callback *mc;
struct sockaddr *dst = sintosa(&icmpsrc);
struct rtentry *rt;
u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */
int error;
rt = rtalloc1(dst, 1);
if (rt == 0)
return;
/* If we didn't get a host route, allocate one */
if ((rt->rt_flags & RTF_HOST) == 0) {
struct rtentry *nrt;
error = rtrequest((int) RTM_ADD, dst,
(struct sockaddr *) rt->rt_gateway,
(struct sockaddr *) 0,
RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt);
if (error) {
rtfree(rt);
return;
}
nrt->rt_rmx = rt->rt_rmx;
rtfree(rt);
rt = nrt;
}
error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q);
if (error) {
rtfree(rt);
return;
}
if (mtu == 0) {
int i = 0;
mtu = ntohs(icp->icmp_ip.ip_len);
/* Some 4.2BSD-based routers incorrectly adjust the ip_len */
if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0)
mtu -= (icp->icmp_ip.ip_hl << 2);
/* If we still can't guess a value, try the route */
if (mtu == 0) {
mtu = rt->rt_rmx.rmx_mtu;
/* If no route mtu, default to the interface mtu */
if (mtu == 0)
mtu = rt->rt_ifp->if_mtu;
}
for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++)
if (mtu > mtu_table[i]) {
mtu = mtu_table[i];
break;
}
}
/*
* XXX: RTV_MTU is overloaded, since the admin can set it
* to turn off PMTU for a route, and the kernel can
* set it to indicate a serious problem with PMTU
* on a route. We should be using a separate flag
* for the kernel to indicate this.
*/
if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
if (mtu < 296 || mtu > rt->rt_ifp->if_mtu)
rt->rt_rmx.rmx_locks |= RTV_MTU;
else if (rt->rt_rmx.rmx_mtu > mtu ||
rt->rt_rmx.rmx_mtu == 0) {
icmpstat.icps_pmtuchg++;
rt->rt_rmx.rmx_mtu = mtu;
}
}
if (rt)
rtfree(rt);
/*
* Notify protocols that the MTU for this destination
* has changed.
*/
for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL;
mc = LIST_NEXT(mc, mc_list))
(*mc->mc_func)(faddr);
}
/*
* Return the next larger or smaller MTU plateau (table from RFC 1191)
* given current value MTU. If DIR is less than zero, a larger plateau
* is returned; otherwise, a smaller value is returned.
*/
int
ip_next_mtu(int mtu, int dir) /* XXX */
{
int i;
for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) {
if (mtu >= mtu_table[i])
break;
}
if (dir < 0) {
if (i == 0) {
return 0;
} else {
return mtu_table[i - 1];
}
} else {
if (mtu_table[i] == 0) {
return 0;
} else if (mtu > mtu_table[i]) {
return mtu_table[i];
} else {
return mtu_table[i + 1];
}
}
}
static void
icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r)
{
if (rt == NULL)
panic("icmp_mtudisc_timeout: bad route to timeout");
if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
(RTF_DYNAMIC | RTF_HOST)) {
rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
} else {
if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
rt->rt_rmx.rmx_mtu = 0;
}
}
}
static void
icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r)
{
if (rt == NULL)
panic("icmp_redirect_timeout: bad route to timeout");
if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) ==
(RTF_DYNAMIC | RTF_HOST)) {
rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
}
}
/*
* Perform rate limit check.
* Returns 0 if it is okay to send the icmp packet.
* Returns 1 if the router SHOULD NOT send this icmp packet due to rate
* limitation.
*
* XXX per-destination/type check necessary?
*/
/* "type" and "code" are not used at this moment */
static int
icmp_ratelimit(const struct in_addr *dst, const int type, const int code)
{
/* PPS limit */
if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count,
icmperrppslim)) {
/* The packet is subject to rate limit */
return 1;
}
/* okay to send */
return 0;
}
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