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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.
*
*
* igmp.c,v 1.2 1994/09/08 02:51:15 wollman Exp
*/
#include "defs.h"
/*
* Exported variables.
*/
char recv_buf[MAX_IP_PACKET_LEN]; /* input packet buffer */
char send_buf[MAX_IP_PACKET_LEN]; /* output packet buffer */
int igmp_socket; /* socket for all network I/O */
u_long allhosts_group; /* allhosts addr in net order */
u_long dvmrp_group; /* DVMRP grp addr in net order */
u_long dvmrp_genid; /* IGMP generation id */
/*
* 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;
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);
}
/* %%% hack for PIM %%% */
#define IGMP_PIM 0x14
#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_char type, code;
{
switch (type) {
case IGMP_HOST_MEMBERSHIP_QUERY: return "membership query ";
case IGMP_HOST_MEMBERSHIP_REPORT: return "membership report ";
case IGMP_HOST_NEW_MEMBERSHIP_REPORT: return "new membership 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 ";
default: return "unknown DVMRP msg ";
}
case IGMP_PIM: /* %%% hack for 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_long 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 shorter (%u bytes) than hdr+data length (%u+%u)",
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:
/* we have to do the determination of the querrier router here */
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:
leave_group_message(src, dst, group);
return;
case IGMP_DVMRP:
switch (igmp->igmp_code) {
case DVMRP_PROBE:
accept_probe(src, dst,
(char *)(igmp+1), igmpdatalen, ntohl(group));
return;
case DVMRP_REPORT:
accept_report(src, dst,
(char *)(igmp+1), igmpdatalen, ntohl(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, (char *)(igmp+1), igmpdatalen,
group);
return;
case DVMRP_NEIGHBORS2:
accept_neighbors2(src, dst, (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;
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: /* %%% hack for PIM %%% */
return;
case IGMP_MTRACE:
mtrace(src, dst, group, (char *)(igmp+1),
igmp->igmp_code, igmpdatalen);
return;
default:
log(LOG_INFO, 0,
"ignoring unknown IGMP message type %u from %s to %s",
igmp->igmp_type, inet_fmt(src, s1),
inet_fmt(dst, s2));
return;
}
}
/*
* 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_long src, dst;
int type, code;
u_long group;
int datalen;
{
static struct sockaddr_in sdst = {AF_INET, sizeof sdst};
struct ip *ip;
struct igmp *igmp;
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;
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 (dst == allhosts_group) k_set_loop(TRUE);
sdst.sin_addr.s_addr = dst;
if (sendto(igmp_socket, send_buf, ip->ip_len, 0,
(struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
if (errno == ENETDOWN)
check_vif_state();
else
log(LOG_WARNING, errno,
"sendto to %s on %s",
inet_fmt(dst, s1), inet_fmt(src, s2));
}
if (dst == allhosts_group) k_set_loop(FALSE);
log(LOG_DEBUG, 0, "SENT %s from %-15s to %s",
packet_kind(type, code), inet_fmt(src, s1), inet_fmt(dst, s2));
}
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