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[unix-history] / sys / netinet / ip_icmp.c
/*
* Copyright (c) 1982, 1986, 1989 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.
*
* from: @(#)ip_icmp.c 7.15 (Berkeley) 4/20/91
* $Id: ip_icmp.c,v 1.5 1993/11/25 01:35:07 wollman Exp $
*/
#include "param.h"
#include "systm.h"
#include "malloc.h"
#include "mbuf.h"
#include "protosw.h"
#include "socket.h"
#include "time.h"
#include "kernel.h"
#include "../net/route.h"
#include "../net/if.h"
#include "in.h"
#include "in_systm.h"
#include "in_var.h"
#include "ip.h"
#include "ip_icmp.h"
#include "icmp_var.h"
/*
* ICMP routines: error generation, receive packet processing, and
* routines to turnaround packets back to the originator, and
* host table maintenance routines.
*/
#define satosin(sa) ((struct sockaddr_in *)(sa))
static void icmp_reflect(struct mbuf *);
static void icmp_send(struct mbuf *, struct mbuf *);
/*
* Generate an error packet of type error
* in response to bad packet ip.
*/
void
icmp_error(n, type, code, dest, mtu)
struct mbuf *n;
int type, code;
struct in_addr dest;
int mtu; /* mtu for ICMP_UNREACH_SRCFRAG */
{
register struct ip *oip = mtod(n, struct ip *), *nip;
register unsigned oiplen = oip->ip_hl << 2;
register struct icmp *icp;
register struct mbuf *m = 0;
unsigned icmplen;
u_long oaddr;
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_error(%x, %d, %d)\n", oip, type, code);
#endif
if (type != ICMP_REDIRECT)
icmpstat.icps_error++;
/*
* Quoth RFC 1122 (Requirements for Internet Hosts):
*
* An ICMP error message MUST NOT be sent as the result of
* receiving:
* - an ICMP error message, or
* - a datagram destined to an IP broadcast or IP multicast
* address, or
* - a datagram sent as a link-layer broadcast, or
* - a non-initial fragment, or
* - a datagram whose source address does not define a single
* host -- e.g., a zero address, a loopback address, a
* broadcast address, a multicast address, or a Class E
* address.
*
* NOTE: THESE RESTRICTIONS TAKE PRECEDENCE OVER ANY REQUIREMENT
* ELSEWHERE IN THIS DOCUMENT FOR SENDING ICMP ERROR MESSAGES.
*/
oaddr = ntohl(oip->ip_src.s_addr);
/*
* Don't send error messages to multicast or broadcast addresses.
*/
if (IN_MULTICAST(oaddr)
|| oaddr == INADDR_BROADCAST
|| n->m_flags & (M_BCAST | M_MCAST)) {
icmpstat.icps_oldmcast++;
goto freeit;
}
/*
* Don't send error messages to zero addresses or class E's.
*/
if (IN_EXPERIMENTAL(oaddr)
|| ! in_lnaof(oip->ip_src)
|| ! in_netof(oip->ip_src)) {
icmpstat.icps_oldbadaddr++;
goto freeit;
}
/*
* Don't send error messages to loopback addresses.
* As a special (unauthorized) exception, we check to see
* if the packet came from the loopback interface. If it
* did, then we should allow the errors through, because
* the upper layers rely on them.
*/
if(in_netof(oip->ip_src) == IN_LOOPBACKNET
&& !(m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK)) {
icmpstat.icps_oldbadaddr++;
goto freeit;
}
/*
* 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_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;
}
/*
* First, formulate icmp message
*/
m = m_gethdr(M_DONTWAIT, MT_HEADER);
if (m == NULL)
goto freeit;
icmplen = oiplen + min(8, oip->ip_len);
m->m_len = icmplen + ICMP_MINLEN;
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 = dest;
else if (type == ICMP_UNREACH && code == ICMP_UNREACH_NEEDFRAG) {
icp->icmp_mtu = htons(mtu);
icp->icmp_mtuvoid = 0;
} else {
icp->icmp_void = 0;
}
if (type == ICMP_PARAMPROB) {
icp->icmp_pptr = code;
code = 0;
}
icp->icmp_code = code;
bcopy((caddr_t)oip, (caddr_t)&icp->icmp_ip, icmplen);
nip = &icp->icmp_ip;
nip->ip_len = htons((u_short)(nip->ip_len + oiplen));
/*
* 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 *);
bcopy((caddr_t)oip, (caddr_t)nip, oiplen);
nip->ip_len = m->m_len;
nip->ip_hl = sizeof(struct ip) >> 2;
nip->ip_p = IPPROTO_ICMP;
icmp_reflect(m);
freeit:
m_freem(n);
}
static struct sockproto icmproto = { AF_INET, IPPROTO_ICMP };
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 };
/*
* Process a received ICMP message.
*/
void
icmp_input(m, hlen)
register struct mbuf *m;
int hlen;
{
register struct icmp *icp;
register struct ip *ip = mtod(m, struct ip *);
int icmplen = ip->ip_len;
register int i;
struct in_ifaddr *ia;
in_ctlinput_t *ctlfunc;
int code;
/*
* Locate icmp structure in mbuf, and check
* that not corrupted and of at least minimum length.
*/
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("icmp_input from %x, len %d\n", ip->ip_src, 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 *);
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:
if (code > ICMP_UNREACH_MAXCODE)
goto badcode;
if (code == ICMP_UNREACH_NEEDFRAG) {
#ifdef MTUDISC
/*
* Need to adjust the routing tables immediately;
* when ULP's get the PRC_MSGSIZE, it is their
* responsibility to notice it and update their
* internal ideas of MTU-derived protocol parameters.
*/
in_mtureduce(icp->icmp_ip.ip_dst,
ntohs(icp->icmp_mtu));
code = PRC_MSGSIZE;
#endif /* MTUDISC */
} else {
code += PRC_UNREACH_NET;
}
goto deliver;
case ICMP_TIMXCEED:
if (code > ICMP_TIMXCEED_MAXCODE)
goto badcode;
code += PRC_TIMXCEED_INTRANS;
goto deliver;
case ICMP_PARAMPROB:
if (code > ICMP_PARAMPROB_MAXCODE)
goto badcode;
code += PRC_PARAMPROB;
goto deliver;
case ICMP_SOURCEQUENCH:
if (code)
goto badcode;
code = PRC_QUENCH;
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;
}
NTOHS(icp->icmp_ip.ip_len);
#ifdef ICMPPRINTFS
if (icmpprintfs)
printf("deliver to protocol %d\n", icp->icmp_ip.ip_p);
#endif
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
if (ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput)
(*ctlfunc)(code, (struct sockaddr *)&icmpsrc,
&icp->icmp_ip);
break;
badcode:
icmpstat.icps_badcode++;
break;
/*
* Always respond to pings from valid addresses.
* Don't respond to broadcast pings unless ipbroadcastecho
* is set. Don't respond to multicast pings unless
* ipbraodcastecho is set AND we support multicasting
* to begin with. (Per RFC 1122, we may choose either.)
*/
case ICMP_ECHO:
{
u_long srcaddr = ntohl(icp->icmp_ip.ip_src.s_addr);
#ifdef MULTICAST
if(IN_MULTICAST(srcaddr) && !ipbroadcastecho)
break;
#else /* not MULTICAST */
if(IN_MULTICAST(srcaddr))
break;
#endif /* not MULTICAST */
if((srcaddr == INADDR_BROADCAST
|| m->m_flags & M_BCAST)
&& !ipbroadcastecho)
break;
}
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;
/*
* Per RFC 1122, only respond to ICMP mask requests
* if the administrator has SPECIFICALLY CONFIGURED
* this host as an address mask agent.
*/
case ICMP_MASKREQ:
if (!ipmaskagent)
break;
if (icmplen < ICMP_MASKLEN ||
(ia = ifptoia(m->m_pkthdr.rcvif)) == 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 = satosin(&ia->ia_broadaddr)->sin_addr;
else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT)
ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr;
}
reflect:
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:
if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp)) {
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 %x to %x\n", icp->icmp_ip.ip_dst,
icp->icmp_gwaddr);
#endif
/*
* Per RFC 1122, throw away redirects that
* suggested places we can't get to, or
* an interface other than the one the packet
* arrived on.
*
* It also says that we SHOULD throw away
* redirects that come from someone other
* than the current first-hop gateway for the
* specified destination.
*
* These are both implemented as general policy
* by rtredirect().
*/
if (code == ICMP_REDIRECT_NET || code == ICMP_REDIRECT_TOSNET) {
icmpsrc.sin_addr =
in_makeaddr(in_netof(icp->icmp_ip.ip_dst), INADDR_ANY);
in_sockmaskof(icp->icmp_ip.ip_dst, &icmpmask);
rtredirect((struct sockaddr *)&icmpsrc,
(struct sockaddr *)&icmpdst,
(struct sockaddr *)&icmpmask, RTF_GATEWAY,
(struct sockaddr *)&icmpgw, (struct rtentry **)0);
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
pfctlinput(PRC_REDIRECT_NET,
(struct sockaddr *)&icmpsrc);
} else {
icmpsrc.sin_addr = icp->icmp_ip.ip_dst;
rtredirect((struct sockaddr *)&icmpsrc,
(struct sockaddr *)&icmpdst,
(struct sockaddr *)0, RTF_GATEWAY | RTF_HOST,
(struct sockaddr *)&icmpgw, (struct rtentry **)0);
pfctlinput(PRC_REDIRECT_HOST,
(struct sockaddr *)&icmpsrc);
}
break;
/*
* No kernel processing for the following;
* just fall through to send to raw listener.
*/
case ICMP_ECHOREPLY:
case ICMP_TSTAMPREPLY:
case ICMP_IREQREPLY:
case ICMP_MASKREPLY:
default:
break;
}
raw:
icmpsrc.sin_addr = ip->ip_src;
icmpdst.sin_addr = ip->ip_dst;
(void) raw_input(m, &icmproto, (struct sockaddr *)&icmpsrc,
(struct sockaddr *)&icmpdst);
return;
freeit:
m_freem(m);
}
/*
* Reflect the ip packet back to the source
*/
static void
icmp_reflect(m)
struct mbuf *m;
{
register struct ip *ip = mtod(m, struct ip *);
register struct in_ifaddr *ia;
struct in_addr t;
struct mbuf *opts = 0, *ip_srcroute();
int optlen = (ip->ip_hl << 2) - sizeof(struct ip);
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; ia; ia = ia->ia_next) {
if (t.s_addr == IA_SIN(ia)->sin_addr.s_addr)
break;
if ((ia->ia_ifp->if_flags & IFF_BROADCAST) &&
t.s_addr == satosin(&ia->ia_broadaddr)->sin_addr.s_addr)
break;
}
if (ia == (struct in_ifaddr *)0)
ia = ifptoia(m->m_pkthdr.rcvif);
if (ia == (struct in_ifaddr *)0)
ia = in_ifaddr;
t = IA_SIN(ia)->sin_addr;
ip->ip_src = t;
ip->ip_ttl = MAXTTL;
if (optlen > 0) {
register 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 {
len = cp[IPOPT_OLEN];
if (len <= 0 || len > cnt)
break;
}
/*
* should check for overflow, but it "can't happen"
*/
if (opt == IPOPT_RR || opt == IPOPT_TS) {
bcopy((caddr_t)cp,
mtod(opts, caddr_t) + opts->m_len, len);
opts->m_len += len;
}
}
if (opts->m_len % 4 != 0) {
*(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)));
}
icmp_send(m, opts);
if (opts)
(void)m_free(opts);
}
struct in_ifaddr *
ifptoia(ifp)
struct ifnet *ifp;
{
register struct in_ifaddr *ia;
for (ia = in_ifaddr; ia; ia = ia->ia_next)
if (ia->ia_ifp == ifp)
return (ia);
return ((struct in_ifaddr *)0);
}
/*
* Send an icmp packet back to the ip level,
* after supplying a checksum.
*/
static void
icmp_send(m, opts)
register struct mbuf *m;
struct mbuf *opts;
{
register struct ip *ip = mtod(m, struct ip *);
register int hlen;
register 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)
printf("icmp_send dst %x src %x\n", ip->ip_dst, ip->ip_src);
#endif
(void) ip_output(m, opts, (struct route *)0, 0);
}
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));
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.