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Kod źródłowy (netinet/ip_icmp.c)
/* $OpenBSD: ip_icmp.c,v 1.53 2002/08/28 15:43:03 pefo Exp $ */
/* $NetBSD: ip_icmp.c,v 1.19 1996/02/13 23:42:22 christos Exp $ */
/*
* 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.
*
* @(#)COPYRIGHT 1.1 (NRL) 17 January 1995
*
* NRL grants permission for redistribution and use in source and binary
* forms, with or without modification, of the software and documentation
* created at NRL 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 acknowledgements:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* This product includes software developed at the Information
* Technology Division, US Naval Research Laboratory.
* 4. Neither the name of the NRL nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL 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 NRL 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.
*
* The views and conclusions contained in the software and documentation
* are those of the authors and should not be interpreted as representing
* official policies, either expressed or implied, of the US Naval
* Research Laboratory (NRL).
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.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/icmp_var.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;
int icmpbmcastecho = 0;
int icmptstamprepl = 1;
#ifdef ICMPPRINTFS
int icmpprintfs = 0;
#endif
int icmperrppslim = 100;
int icmperrpps_count = 0;
struct timeval icmperrppslim_last;
int icmp_rediraccept = 1;
int icmp_redirtimeout = 10 * 60;
static struct rttimer_queue *icmp_redirect_timeout_q = NULL;
void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *);
int icmp_ratelimit(const struct in_addr *, const int, const int);
static void icmp_redirect_timeout(struct rtentry *, struct rttimer *);
extern struct protosw inetsw[];
void
icmp_init()
{
/*
* 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);
}
}
struct mbuf *
icmp_do_error(n, type, code, dest, destifp)
struct mbuf *n;
int type, code;
n_long dest;
struct ifnet *destifp;
{
struct ip *oip = mtod(n, struct ip *), *nip;
unsigned oiplen = oip->ip_hl << 2;
struct icmp *icp;
struct mbuf *m;
struct m_tag *mtag;
unsigned icmplen, mblen;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_error(%x, %d, %d)\n", oip, type, code);
#endif
if (type != ICMP_REDIRECT)
icmpstat.icps_error++;
/*
* 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 (oip->ip_off & IP_OFFMASK)
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(8, oip->ip_len);
/*
* Defend against mbuf chains shorter than oip->ip_len:
*/
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;
*/
KASSERT(ICMP_MINLEN <= MCLBYTES);
if (icmplen + ICMP_MINLEN > MCLBYTES)
icmplen = MCLBYTES - ICMP_MINLEN - sizeof (struct ip);
m = m_gethdr(M_DONTWAIT, MT_HEADER);
if (m && (sizeof (struct ip) + 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;
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 && destifp)
icp->icmp_nextmtu = htons(destifp->if_mtu);
}
HTONS(oip->ip_off);
HTONS(oip->ip_len);
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_flags & M_EXT) == 0 &&
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 = m->m_len;
/* ip_id set in ip_output */
nip->ip_off = 0;
/* ip_ttl set in icmp_reflect */
nip->ip_p = IPPROTO_ICMP;
nip->ip_src = oip->ip_src;
nip->ip_dst = oip->ip_dst;
/* move PF_GENERATED m_tag to new packet, if it exists */
mtag = m_tag_find(n, PACKET_TAG_PF_GENERATED, NULL);
if (mtag != NULL) {
m_tag_unlink(n, mtag);
m_tag_prepend(m, mtag);
}
m_freem(n);
return (m);
freeit:
m_freem(n);
return (NULL);
}
/*
* Generate an error packet of type error
* in response to bad packet ip.
*
* The ip packet inside has ip_off and ip_len in host byte order.
*/
void
icmp_error(n, type, code, dest, destifp)
struct mbuf *n;
int type, code;
n_long dest;
struct ifnet *destifp;
{
struct mbuf *m;
m = icmp_do_error(n, type, code, dest, destifp);
if (m != NULL)
icmp_reflect(m);
}
static 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, ...)
{
struct icmp *icp;
struct ip *ip = mtod(m, struct ip *);
int icmplen = ip->ip_len;
int i;
struct in_ifaddr *ia;
void *(*ctlfunc)(int, struct sockaddr *, void *);
int code;
extern u_char ip_protox[];
int hlen;
va_list ap;
struct rtentry *rt;
va_start(ap, m);
hlen = va_arg(ap, int);
va_end(ap);
/*
* Locate icmp structure in mbuf, and check
* that not corrupted and of at least minimum length.
*/
#ifdef ICMPPRINTFS
if (icmpprintfs) {
char buf[4*sizeof "123"];
strcpy(buf, inet_ntoa(ip->ip_dst));
printf("icmp_input from %s to %s, len %d\n",
inet_ntoa(ip->ip_src), buf, 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)) == NULL) {
icmpstat.icps_tooshort++;
return;
}
ip = mtod(m, struct ip *);
m->m_len -= hlen;
m->m_data += hlen;
icp = mtod(m, struct icmp *);
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:
case ICMP_UNREACH_FILTER_PROHIB:
case ICMP_UNREACH_HOST_PRECEDENCE:
case ICMP_UNREACH_PRECEDENCE_CUTOFF:
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;
deliver:
/* Free packet atttributes */
if (m->m_flags & M_PKTHDR)
m_tag_delete_chain(m, NULL);
/*
* 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;
NTOHS(icp->icmp_ip.ip_len);
#ifdef INET6
/* Get more contiguous data for a v6 in v4 ICMP message. */
if (icp->icmp_ip.ip_p == IPPROTO_IPV6) {
if (icmplen < ICMP_V6ADVLENMIN ||
icmplen < ICMP_V6ADVLEN(icp)) {
icmpstat.icps_badlen++;
goto freeit;
} else {
if ((m = m_pullup(m, (ip->ip_hl << 2) +
ICMP_V6ADVLEN(icp))) == NULL) {
icmpstat.icps_tooshort++;
return;
}
ip = mtod(m, struct ip *);
icp = (struct icmp *)(m->m_data + (ip->ip_hl << 2));
}
}
#endif /* INET6 */
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
#endif
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
/*
* XXX if the packet contains [IPv4 AH TCP], we can't make a
* notification to TCP layer.
*/
ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput;
if (ctlfunc)
(*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip);
break;
badcode:
icmpstat.icps_badcode++;
break;
case ICMP_ECHO:
if (!icmpbmcastecho &&
(m->m_flags & (M_MCAST | M_BCAST)) != 0) {
icmpstat.icps_bmcastecho++;
break;
}
icp->icmp_type = ICMP_ECHOREPLY;
goto reflect;
case ICMP_TSTAMP:
if (icmptstamprepl == 0)
break;
if (!icmpbmcastecho &&
(m->m_flags & (M_MCAST | M_BCAST)) != 0) {
icmpstat.icps_bmcastecho++;
break;
}
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 ||
ip->ip_dst.s_addr == INADDR_ANY)
icmpdst.sin_addr = ip->ip_src;
else
icmpdst.sin_addr = ip->ip_dst;
if (m->m_pkthdr.rcvif == NULL)
break;
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 (ip->ip_src.s_addr == 0) {
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:
/* Free packet atttributes */
if (m->m_flags & M_PKTHDR)
m_tag_delete_chain(m, NULL);
ip->ip_len += hlen; /* since ip_input deducts this */
icmpstat.icps_reflect++;
icmpstat.icps_outhist[icp->icmp_type]++;
icmp_reflect(m);
return;
case ICMP_REDIRECT:
/* Free packet atttributes */
if (m->m_flags & M_PKTHDR)
m_tag_delete_chain(m, NULL);
if (icmp_rediraccept == 0)
goto freeit;
if (code > 3)
goto badcode;
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) {
char buf[4 * sizeof "123"];
strcpy(buf, inet_ntoa(icp->icmp_ip.ip_dst));
printf("redirect dst %s to %s\n",
buf, 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) {
(void)rt_timer_add(rt, icmp_redirect_timeout,
icmp_redirect_timeout_q);
}
if (rt != NULL)
rtfree(rt);
pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc));
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:
case ICMP_TRACEROUTE:
case ICMP_DATACONVERR:
case ICMP_MOBILE_REDIRECT:
case ICMP_IPV6_WHEREAREYOU:
case ICMP_IPV6_IAMHERE:
case ICMP_MOBILE_REGREQUEST:
case ICMP_MOBILE_REGREPLY:
case ICMP_PHOTURIS:
default:
break;
}
raw:
rip_input(m);
return;
freeit:
m_freem(m);
}
/*
* Reflect the ip packet back to the source
*/
void
icmp_reflect(m)
struct mbuf *m;
{
struct ip *ip = mtod(m, struct ip *);
struct in_ifaddr *ia;
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 the address which corresponds
* to the incoming interface.
*/
for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) {
if (t.s_addr == ia->ia_addr.sin_addr.s_addr)
break;
if ((ia->ia_ifp->if_flags & IFF_BROADCAST) &&
t.s_addr == ia->ia_broadaddr.sin_addr.s_addr)
break;
}
icmpdst.sin_addr = t;
if ((ia == (struct in_ifaddr *)0) && (m->m_pkthdr.rcvif != NULL))
ia = ifatoia(ifaof_ifpforaddr(sintosa(&icmpdst),
m->m_pkthdr.rcvif));
/*
* The following happens if the packet was not addressed to us,
* and was received on an interface with no IP address.
*/
if (ia == (struct in_ifaddr *)0) {
struct sockaddr_in *dst;
struct route ro;
bzero((caddr_t) &ro, sizeof(ro));
dst = satosin(&ro.ro_dst);
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = t;
rtalloc(&ro);
if (ro.ro_rt == 0)
{
ipstat.ips_noroute++;
goto done;
}
ia = ifatoia(ro.ro_rt->rt_ifa);
ro.ro_rt->rt_use++;
RTFREE(ro.ro_rt);
}
t = ia->ia_addr.sin_addr;
ip->ip_src = t;
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))) {
opts->m_len = sizeof(struct in_addr);
mtod(opts, struct in_addr *)->s_addr = 0;
}
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 -= 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->m_flags &= ~(M_BCAST|M_MCAST);
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(m, opts)
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, ip->ip_len - hlen);
m->m_data -= hlen;
m->m_len += hlen;
#ifdef ICMPPRINTFS
if (icmpprintfs) {
char buf[4 * sizeof "123"];
strcpy(buf, inet_ntoa(ip->ip_dst));
printf("icmp_send dst %s src %s\n",
buf, inet_ntoa(ip->ip_src));
}
#endif
(void) ip_output(m, opts, (void *)NULL, 0, (void *)NULL, (void *)NULL);
}
n_time
iptime()
{
struct timeval atv;
u_long t;
microtime(&atv);
t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000;
return (htonl(t));
}
int
icmp_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
int *name;
u_int namelen;
void *oldp;
size_t *oldlenp;
void *newp;
size_t newlen;
{
/* All sysctl names at this level are terminal. */
if (namelen != 1)
return (ENOTDIR);
switch (name[0]) {
case ICMPCTL_TSTAMPREPL:
return (sysctl_int(oldp, oldlenp, newp, newlen, &icmptstamprepl));
case ICMPCTL_MASKREPL:
return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpmaskrepl));
case ICMPCTL_BMCASTECHO:
return (sysctl_int(oldp, oldlenp, newp, newlen, &icmpbmcastecho));
case ICMPCTL_ERRPPSLIMIT:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&icmperrppslim));
break;
case ICMPCTL_REDIRACCEPT:
return (sysctl_int(oldp, oldlenp, newp, newlen,
&icmp_rediraccept));
break;
case ICMPCTL_REDIRTIMEOUT: {
int error;
error = sysctl_int(oldp, oldlenp, newp, newlen,
&icmp_redirtimeout);
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 (error);
break;
}
default:
return (ENOPROTOOPT);
}
/* NOTREACHED */
}
struct rtentry *
icmp_mtudisc_clone(struct sockaddr *dst)
{
struct rtentry *rt;
int error;
rt = rtalloc1(dst, 1);
if (rt == 0)
return (NULL);
/* 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 (NULL);
}
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 (NULL);
}
return (rt);
}
void
icmp_mtudisc(icp)
struct icmp *icp;
{
struct rtentry *rt;
struct sockaddr *dst = sintosa(&icmpsrc);
u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */
/* Table of common MTUs: */
static u_short mtu_table[] = {65535, 65280, 32000, 17914, 9180, 8166,
4352, 2002, 1492, 1006, 508, 296, 68, 0};
rt = icmp_mtudisc_clone(dst);
if (rt == 0)
return;
if (mtu == 0) {
int i = 0;
mtu = icp->icmp_ip.ip_len; /* NTOHS happened in deliver: */
/* 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)
rt->rt_rmx.rmx_mtu = mtu;
}
rtfree(rt);
}
void
icmp_mtudisc_timeout(rt, r)
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)) {
void *(*ctlfunc)(int, struct sockaddr *, void *);
extern u_char ip_protox[];
struct sockaddr_in sa;
sa = *(struct sockaddr_in *)rt_key(rt);
rtrequest((int) RTM_DELETE, (struct sockaddr *)rt_key(rt),
rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
/* Notify TCP layer of increased Path MTU estimate */
ctlfunc = inetsw[ip_protox[IPPROTO_TCP]].pr_ctlinput;
if (ctlfunc)
(*ctlfunc)(PRC_MTUINC,(struct sockaddr *)&sa, NULL);
} else {
if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) {
rt->rt_rmx.rmx_mtu = 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?
*/
int
icmp_ratelimit(dst, type, code)
const struct in_addr *dst;
const int type; /* not used at this moment */
const int code; /* not used at this moment */
{
/* PPS limit */
if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count,
icmperrppslim)) {
/* The packet is subject to rate limit */
return 1;
}
/*okay to send*/
return 0;
}
static void
icmp_redirect_timeout(rt, r)
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);
}
}
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