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/*
* The mrouted program is covered by the license in the accompanying file
* named "LICENSE". Use of the mrouted program represents acceptance of
* the terms and conditions listed in that file.
*
* The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
* Leland Stanford Junior University.
*
*
* icmp.c,v 3.8.4.2 1998/01/06 01:57:42 fenner Exp
*/
#include "defs.h"
#ifndef lint
static char rcsid[] = "@(#) $Id: \
icmp.c,v 3.8.4.2 1998/01/06 01:57:42 fenner Exp $";
#endif
static int icmp_socket;
static void icmp_handler __P((int, fd_set *));
static char * icmp_name __P((struct icmp *));
void
init_icmp()
{
if ((icmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0)
log(LOG_ERR, errno, "ICMP socket");
register_input_handler(icmp_socket, icmp_handler);
IF_DEBUG(DEBUG_ICMP)
log(LOG_DEBUG, 0, "registering icmp socket fd %d\n", icmp_socket);
}
static void
icmp_handler(fd, rfds)
int fd;
fd_set *rfds;
{
u_char icmp_buf[RECV_BUF_SIZE];
struct sockaddr_in from;
int fromlen, recvlen, iphdrlen, ipdatalen;
struct icmp *icmp;
struct ip *ip;
vifi_t i;
struct uvif *v;
u_int32 src;
fromlen = sizeof(from);
recvlen = recvfrom(icmp_socket, icmp_buf, RECV_BUF_SIZE, 0,
(struct sockaddr *)&from, &fromlen);
if (recvlen < 0) {
if (errno != EINTR)
log(LOG_WARNING, errno, "icmp_socket recvfrom");
return;
}
ip = (struct ip *)icmp_buf;
iphdrlen = ip->ip_hl << 2;
#ifdef RAW_INPUT_IS_RAW
ipdatalen = ntohs(ip->ip_len) - iphdrlen;
#else
ipdatalen = ip->ip_len;
#endif
if (iphdrlen + ipdatalen != recvlen) {
IF_DEBUG(DEBUG_ICMP)
log(LOG_DEBUG, 0, "hdr %d data %d != rcv %d", iphdrlen, ipdatalen, recvlen);
/* Malformed ICMP, just return. */
return;
}
if (ipdatalen < ICMP_MINLEN + sizeof(struct ip)) {
/* Not enough data for us to be interested in it. */
return;
}
src = ip->ip_src.s_addr;
icmp = (struct icmp *)(icmp_buf + iphdrlen);
IF_DEBUG(DEBUG_ICMP)
log(LOG_DEBUG, 0, "got ICMP type %d from %s",
icmp->icmp_type, inet_fmt(src, s1));
/*
* Eventually:
* have registry of ICMP listeners, by type, code and ICMP_ID
* (and maybe fields of the original packet too -- maybe need a
* generalized packet filter!) to allow ping and traceroute
* from the monitoring tool.
*/
switch (icmp->icmp_type) {
case ICMP_UNREACH:
case ICMP_TIMXCEED:
/* Look at returned packet to see if it's us sending on a tunnel */
ip = &icmp->icmp_ip;
if (ip->ip_p != IPPROTO_IGMP && ip->ip_p != IPPROTO_IPIP)
return;
for (v = uvifs, i = 0; i < numvifs; v++, i++) {
if (ip->ip_src.s_addr == v->uv_lcl_addr &&
ip->ip_dst.s_addr == v->uv_dst_addr) {
char *p;
int n;
/*
* I sent this packet on this vif.
*/
n = ++v->uv_icmp_warn;
while (n && !(n & 1))
n >>= 1;
if (n == 1 && ((p = icmp_name(icmp)) != NULL))
log(LOG_WARNING, 0, "Received ICMP %s from %s %s %s on vif %d",
p, inet_fmt(src, s1), "for traffic sent to",
inet_fmt(ip->ip_dst.s_addr, s2),
i);
break;
}
}
break;
}
}
/*
* Return NULL for ICMP informational messages.
* Return string describing the error for ICMP errors.
*/
static char *
icmp_name(icmp)
struct icmp *icmp;
{
static char retval[30];
switch (icmp->icmp_type) {
case ICMP_UNREACH:
switch (icmp->icmp_code) {
case ICMP_UNREACH_NET:
return "network unreachable";
case ICMP_UNREACH_HOST:
return "host unreachable";
case ICMP_UNREACH_PROTOCOL:
return "protocol unreachable";
case ICMP_UNREACH_PORT:
return "port unreachable";
case ICMP_UNREACH_NEEDFRAG:
return "needs fragmentation";
case ICMP_UNREACH_SRCFAIL:
return "source route failed";
#ifndef ICMP_UNREACH_NET_UNKNOWN
#define ICMP_UNREACH_NET_UNKNOWN 6
#endif
case ICMP_UNREACH_NET_UNKNOWN:
return "network unknown";
#ifndef ICMP_UNREACH_HOST_UNKNOWN
#define ICMP_UNREACH_HOST_UNKNOWN 7
#endif
case ICMP_UNREACH_HOST_UNKNOWN:
return "host unknown";
#ifndef ICMP_UNREACH_ISOLATED
#define ICMP_UNREACH_ISOLATED 8
#endif
case ICMP_UNREACH_ISOLATED:
return "source host isolated";
#ifndef ICMP_UNREACH_NET_PROHIB
#define ICMP_UNREACH_NET_PROHIB 9
#endif
case ICMP_UNREACH_NET_PROHIB:
return "network access prohibited";
#ifndef ICMP_UNREACH_HOST_PROHIB
#define ICMP_UNREACH_HOST_PROHIB 10
#endif
case ICMP_UNREACH_HOST_PROHIB:
return "host access prohibited";
#ifndef ICMP_UNREACH_TOSNET
#define ICMP_UNREACH_TOSNET 11
#endif
case ICMP_UNREACH_TOSNET:
return "bad TOS for net";
#ifndef ICMP_UNREACH_TOSHOST
#define ICMP_UNREACH_TOSHOST 12
#endif
case ICMP_UNREACH_TOSHOST:
return "bad TOS for host";
#ifndef ICMP_UNREACH_FILTER_PROHIB
#define ICMP_UNREACH_FILTER_PROHIB 13
#endif
case ICMP_UNREACH_FILTER_PROHIB:
return "prohibited by filter";
#ifndef ICMP_UNREACH_HOST_PRECEDENCE
#define ICMP_UNREACH_HOST_PRECEDENCE 14
#endif
case ICMP_UNREACH_HOST_PRECEDENCE:
return "host precedence violation";
#ifndef ICMP_UNREACH_PRECEDENCE_CUTOFF
#define ICMP_UNREACH_PRECEDENCE_CUTOFF 15
#endif
case ICMP_UNREACH_PRECEDENCE_CUTOFF:
return "precedence cutoff";
default:
sprintf(retval, "unreachable code %d", icmp->icmp_code);
return retval;
}
case ICMP_SOURCEQUENCH:
return "source quench";
case ICMP_REDIRECT:
return NULL; /* XXX */
case ICMP_TIMXCEED:
switch (icmp->icmp_code) {
case ICMP_TIMXCEED_INTRANS:
return "time exceeded in transit";
case ICMP_TIMXCEED_REASS:
return "time exceeded in reassembly";
default:
sprintf(retval, "time exceeded code %d", icmp->icmp_code);
return retval;
}
case ICMP_PARAMPROB:
switch (icmp->icmp_code) {
#ifndef ICMP_PARAMPROB_OPTABSENT
#define ICMP_PARAMPROB_OPTABSENT 1
#endif
case ICMP_PARAMPROB_OPTABSENT:
return "required option absent";
default:
sprintf(retval, "parameter problem code %d", icmp->icmp_code);
return retval;
}
}
return NULL;
}
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