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freebsd-dev/usr.sbin/mrouted/igmp.c
Bill Fenner f014b7e69b Update to the unreleased mrouted 3.8a . This includes a minor 
endian-ness fix, Router Alert options on IGMP messages, and a
new keyword, "advert_metric", for fine-tuning tunnel metrics.

This also includes a new mtrace, which is also unreleased but
builds significantly on the experiences of users' troubles with
using and understanding mtrace in release 3.8 .

(unreleased does not, of course, mean untested!)

This is a candidate for both 2.2 and 2.1.6 .
1996-11-11 03:50:15 +00:00

468 lines
13 KiB
C
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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.
*
*
* $Id: igmp.c,v 3.8.1.1 1996/08/09 22:49:12 fenner Exp $
*/
#include "defs.h"
/*
* Exported variables.
*/
char *recv_buf; /* input packet buffer */
char *send_buf; /* output packet buffer */
int igmp_socket; /* socket for all network I/O */
u_int32 allhosts_group; /* All hosts addr in net order */
u_int32 allrtrs_group; /* All-Routers " in net order */
u_int32 dvmrp_group; /* DVMRP grp addr in net order */
u_int32 dvmrp_genid; /* IGMP generation id */
/*
* Private variables
*/
static char router_alert[4]; /* Router Alert IP Option */
#ifndef IPOPT_RA
#define IPOPT_RA 148
#endif
#ifdef SUNOS5
static char no_op[4]; /* Null IP Option */
static int ip_addlen = 0; /* Workaround for Option bug #2*/
#endif
#define SEND_RA(x) (((x) == IGMP_MEMBERSHIP_QUERY) || \
((x) == IGMP_V1_MEMBERSHIP_REPORT) || \
((x) == IGMP_V2_MEMBERSHIP_REPORT) || \
((x) == IGMP_V2_LEAVE_GROUP) || \
((x) == IGMP_MTRACE))
/*
* Local function definitions.
*/
/* u_char promoted to u_int */
static char * packet_kind __P((u_int type, u_int code));
static int igmp_log_level __P((u_int type, u_int code));
/*
* Open and initialize the igmp socket, and fill in the non-changing
* IP header fields in the output packet buffer.
*/
void
init_igmp()
{
struct ip *ip;
#ifdef SUNOS5
u_int32 localhost = htonl(0x7f000001);
#endif
recv_buf = malloc(RECV_BUF_SIZE);
send_buf = malloc(RECV_BUF_SIZE);
if ((igmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP)) < 0)
log(LOG_ERR, errno, "IGMP socket");
k_hdr_include(TRUE); /* include IP header when sending */
k_set_rcvbuf(48*1024); /* lots of input buffering */
k_set_ttl(1); /* restrict multicasts to one hop */
k_set_loop(FALSE); /* disable multicast loopback */
ip = (struct ip *)send_buf;
ip->ip_hl = sizeof(struct ip) >> 2;
ip->ip_v = IPVERSION;
ip->ip_tos = 0;
ip->ip_off = 0;
ip->ip_p = IPPROTO_IGMP;
ip->ip_ttl = MAXTTL; /* applies to unicasts only */
allhosts_group = htonl(INADDR_ALLHOSTS_GROUP);
dvmrp_group = htonl(INADDR_DVMRP_GROUP);
allrtrs_group = htonl(INADDR_ALLRTRS_GROUP);
router_alert[0] = IPOPT_RA; /* Router Alert */
router_alert[1] = 4; /* 4 bytes */
router_alert[2] = 0;
router_alert[3] = 0;
#ifdef SUNOS5
no_op[0] = IPOPT_NOP;
no_op[1] = IPOPT_NOP;
no_op[2] = IPOPT_NOP;
no_op[3] = IPOPT_NOP;
setsockopt(igmp_socket, IPPROTO_IP, IP_OPTIONS, no_op, sizeof(no_op));
/*
* Check if the kernel adds the options length to the packet
* length. Send myself an IGMP packet of type 0 (illegal),
* with 4 IPOPT_NOP options, my PID (for collision detection)
* and 4 bytes of zero (so that the checksum works whether
* the 4 bytes of zero get truncated or not).
*/
bzero(send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN, 8);
*(int *)(send_buf + MIN_IP_HEADER_LEN + IGMP_MINLEN) = getpid();
send_igmp(localhost, localhost, 0, 0, 0, 8);
while (1) {
int recvlen, dummy = 0;
recvlen = recvfrom(igmp_socket, recv_buf, RECV_BUF_SIZE,
0, NULL, &dummy);
/* 8 == 4 bytes of options and 4 bytes of PID */
if (recvlen >= MIN_IP_HEADER_LEN + IGMP_MINLEN + 8) {
struct ip *ip = (struct ip *)recv_buf;
struct igmp *igmp;
int *p;
if (ip->ip_hl != 6 ||
ip->ip_p != IPPROTO_IGMP ||
ip->ip_src.s_addr != localhost ||
ip->ip_dst.s_addr != localhost)
continue;
igmp = (struct igmp *)(recv_buf + (ip->ip_hl << 2));
if (igmp->igmp_group.s_addr != 0)
continue;
if (igmp->igmp_type != 0 || igmp->igmp_code != 0)
continue;
p = (int *)((char *)igmp + IGMP_MINLEN);
if (*p != getpid())
continue;
if (ip->ip_len == IGMP_MINLEN + 4)
ip_addlen = 4;
else if (ip->ip_len == IGMP_MINLEN + 8)
ip_addlen = 0;
else
log(LOG_ERR, 0, "while checking for Solaris bug: Sent %d bytes and got back %d!", IGMP_MINLEN + 8, ip->ip_len);
break;
}
}
#endif
}
#define PIM_QUERY 0
#define PIM_REGISTER 1
#define PIM_REGISTER_STOP 2
#define PIM_JOIN_PRUNE 3
#define PIM_RP_REACHABLE 4
#define PIM_ASSERT 5
#define PIM_GRAFT 6
#define PIM_GRAFT_ACK 7
static char *
packet_kind(type, code)
u_int type, code;
{
switch (type) {
case IGMP_HOST_MEMBERSHIP_QUERY: return "membership query ";
case IGMP_HOST_MEMBERSHIP_REPORT: return "V1 member report ";
case IGMP_HOST_NEW_MEMBERSHIP_REPORT: return "V2 member report ";
case IGMP_HOST_LEAVE_MESSAGE: return "leave message ";
case IGMP_DVMRP:
switch (code) {
case DVMRP_PROBE: return "neighbor probe ";
case DVMRP_REPORT: return "route report ";
case DVMRP_ASK_NEIGHBORS: return "neighbor request ";
case DVMRP_NEIGHBORS: return "neighbor list ";
case DVMRP_ASK_NEIGHBORS2: return "neighbor request 2";
case DVMRP_NEIGHBORS2: return "neighbor list 2 ";
case DVMRP_PRUNE: return "prune message ";
case DVMRP_GRAFT: return "graft message ";
case DVMRP_GRAFT_ACK: return "graft message ack ";
case DVMRP_INFO_REQUEST: return "info request ";
case DVMRP_INFO_REPLY: return "info reply ";
default: return "unknown DVMRP msg ";
}
case IGMP_PIM:
switch (code) {
case PIM_QUERY: return "PIM Router-Query ";
case PIM_REGISTER: return "PIM Register ";
case PIM_REGISTER_STOP: return "PIM Register-Stop ";
case PIM_JOIN_PRUNE: return "PIM Join/Prune ";
case PIM_RP_REACHABLE: return "PIM RP-Reachable ";
case PIM_ASSERT: return "PIM Assert ";
case PIM_GRAFT: return "PIM Graft ";
case PIM_GRAFT_ACK: return "PIM Graft-Ack ";
default: return "unknown PIM msg ";
}
case IGMP_MTRACE: return "IGMP trace query ";
case IGMP_MTRACE_RESP: return "IGMP trace reply ";
default: return "unknown IGMP msg ";
}
}
/*
* Process a newly received IGMP packet that is sitting in the input
* packet buffer.
*/
void
accept_igmp(recvlen)
int recvlen;
{
register u_int32 src, dst, group;
struct ip *ip;
struct igmp *igmp;
int ipdatalen, iphdrlen, igmpdatalen;
if (recvlen < sizeof(struct ip)) {
log(LOG_WARNING, 0,
"received packet too short (%u bytes) for IP header", recvlen);
return;
}
ip = (struct ip *)recv_buf;
src = ip->ip_src.s_addr;
dst = ip->ip_dst.s_addr;
/*
* this is most likely a message from the kernel indicating that
* a new src grp pair message has arrived and so, it would be
* necessary to install a route into the kernel for this.
*/
if (ip->ip_p == 0) {
if (src == 0 || dst == 0)
log(LOG_WARNING, 0, "kernel request not accurate");
else
add_table_entry(src, dst);
return;
}
iphdrlen = ip->ip_hl << 2;
ipdatalen = ip->ip_len;
if (iphdrlen + ipdatalen != recvlen) {
log(LOG_WARNING, 0,
"received packet from %s shorter (%u bytes) than hdr+data length (%u+%u)",
inet_fmt(src, s1), recvlen, iphdrlen, ipdatalen);
return;
}
igmp = (struct igmp *)(recv_buf + iphdrlen);
group = igmp->igmp_group.s_addr;
igmpdatalen = ipdatalen - IGMP_MINLEN;
if (igmpdatalen < 0) {
log(LOG_WARNING, 0,
"received IP data field too short (%u bytes) for IGMP, from %s",
ipdatalen, inet_fmt(src, s1));
return;
}
log(LOG_DEBUG, 0, "RECV %s from %-15s to %s",
packet_kind(igmp->igmp_type, igmp->igmp_code),
inet_fmt(src, s1), inet_fmt(dst, s2));
switch (igmp->igmp_type) {
case IGMP_HOST_MEMBERSHIP_QUERY:
accept_membership_query(src, dst, group, igmp->igmp_code);
return;
case IGMP_HOST_MEMBERSHIP_REPORT:
case IGMP_HOST_NEW_MEMBERSHIP_REPORT:
accept_group_report(src, dst, group, igmp->igmp_type);
return;
case IGMP_HOST_LEAVE_MESSAGE:
accept_leave_message(src, dst, group);
return;
case IGMP_DVMRP:
group = ntohl(group);
switch (igmp->igmp_code) {
case DVMRP_PROBE:
accept_probe(src, dst,
(char *)(igmp+1), igmpdatalen, group);
return;
case DVMRP_REPORT:
accept_report(src, dst,
(char *)(igmp+1), igmpdatalen, group);
return;
case DVMRP_ASK_NEIGHBORS:
accept_neighbor_request(src, dst);
return;
case DVMRP_ASK_NEIGHBORS2:
accept_neighbor_request2(src, dst);
return;
case DVMRP_NEIGHBORS:
accept_neighbors(src, dst, (u_char *)(igmp+1), igmpdatalen,
group);
return;
case DVMRP_NEIGHBORS2:
accept_neighbors2(src, dst, (u_char *)(igmp+1), igmpdatalen,
group);
return;
case DVMRP_PRUNE:
accept_prune(src, dst, (char *)(igmp+1), igmpdatalen);
return;
case DVMRP_GRAFT:
accept_graft(src, dst, (char *)(igmp+1), igmpdatalen);
return;
case DVMRP_GRAFT_ACK:
accept_g_ack(src, dst, (char *)(igmp+1), igmpdatalen);
return;
case DVMRP_INFO_REQUEST:
accept_info_request(src, dst, (char *)(igmp+1),
igmpdatalen);
return;
case DVMRP_INFO_REPLY:
accept_info_reply(src, dst, (char *)(igmp+1), igmpdatalen);
return;
default:
log(LOG_INFO, 0,
"ignoring unknown DVMRP message code %u from %s to %s",
igmp->igmp_code, inet_fmt(src, s1),
inet_fmt(dst, s2));
return;
}
case IGMP_PIM:
return;
case IGMP_MTRACE_RESP:
return;
case IGMP_MTRACE:
accept_mtrace(src, dst, group, (char *)(igmp+1),
igmp->igmp_code, igmpdatalen);
return;
default:
log(LOG_INFO, 0,
"ignoring unknown IGMP message type %x from %s to %s",
igmp->igmp_type, inet_fmt(src, s1),
inet_fmt(dst, s2));
return;
}
}
/*
* Some IGMP messages are more important than others. This routine
* determines the logging level at which to log a send error (often
* "No route to host"). This is important when there is asymmetric
* reachability and someone is trying to, i.e., mrinfo me periodically.
*/
static int
igmp_log_level(type, code)
u_int type, code;
{
switch (type) {
case IGMP_MTRACE_RESP:
return LOG_INFO;
case IGMP_DVMRP:
switch (code) {
case DVMRP_NEIGHBORS:
case DVMRP_NEIGHBORS2:
return LOG_INFO;
}
}
return LOG_WARNING;
}
/*
* Construct an IGMP message in the output packet buffer. The caller may
* have already placed data in that buffer, of length 'datalen'. Then send
* the message from the interface with IP address 'src' to destination 'dst'.
*/
void
send_igmp(src, dst, type, code, group, datalen)
u_int32 src, dst;
int type, code;
u_int32 group;
int datalen;
{
struct sockaddr_in sdst;
struct ip *ip;
struct igmp *igmp;
int setloop = 0;
static int raset = 0;
int sendra = 0;
int sendlen;
ip = (struct ip *)send_buf;
ip->ip_src.s_addr = src;
ip->ip_dst.s_addr = dst;
ip->ip_len = MIN_IP_HEADER_LEN + IGMP_MINLEN + datalen;
sendlen = ip->ip_len;
#ifdef SUNOS5
ip->ip_len += ip_addlen;
#endif
igmp = (struct igmp *)(send_buf + MIN_IP_HEADER_LEN);
igmp->igmp_type = type;
igmp->igmp_code = code;
igmp->igmp_group.s_addr = group;
igmp->igmp_cksum = 0;
igmp->igmp_cksum = inet_cksum((u_short *)igmp,
IGMP_MINLEN + datalen);
if (IN_MULTICAST(ntohl(dst))) {
k_set_if(src);
if (type != IGMP_DVMRP || dst == allhosts_group) {
setloop = 1;
k_set_loop(TRUE);
}
if (SEND_RA(type))
sendra = 1;
}
if (sendra && !raset) {
setsockopt(igmp_socket, IPPROTO_IP, IP_OPTIONS,
router_alert, sizeof(router_alert));
raset = 1;
} else if (!sendra && raset) {
#ifdef SUNOS5
/*
* SunOS5 < 5.6 cannot properly reset the IP_OPTIONS "socket"
* option. Instead, set up a string of 4 no-op's.
*/
setsockopt(igmp_socket, IPPROTO_IP, IP_OPTIONS,
no_op, sizeof(no_op));
#else
setsockopt(igmp_socket, IPPROTO_IP, IP_OPTIONS,
NULL, 0);
#endif
raset = 0;
}
bzero(&sdst, sizeof(sdst));
sdst.sin_family = AF_INET;
#if (defined(BSD) && (BSD >= 199103))
sdst.sin_len = sizeof(sdst);
#endif
sdst.sin_addr.s_addr = dst;
if (sendto(igmp_socket, send_buf, sendlen, 0,
(struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
if (errno == ENETDOWN)
check_vif_state();
else
log(igmp_log_level(type, code), errno,
"sendto to %s on %s",
inet_fmt(dst, s1), inet_fmt(src, s2));
}
if (setloop)
k_set_loop(FALSE);
log(LOG_DEBUG, 0, "SENT %s from %-15s to %s",
packet_kind(type, code), src == INADDR_ANY ? "INADDR_ANY" :
inet_fmt(src, s1), inet_fmt(dst, s2));
}
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