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NetBSD/usr.sbin/mrouted/igmp.c

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/* $NetBSD: igmp.c,v 1.14 2009/04/17 16:05:43 lukem Exp $ */
/*
* 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.
*/
#include "defs.h"
/*
* Exported variables.
*/
char *recv_buf; /* input packet buffer */
char *send_buf; /* output packet buffer */
size_t send_buflen; /* output packet buffer */
int igmp_socket; /* socket for all network I/O */
u_int32_t allhosts_group; /* All hosts addr in net order */
u_int32_t allrtrs_group; /* All-Routers " in net order */
u_int32_t dvmrp_group; /* DVMRP grp addr in net order */
u_int32_t dvmrp_genid; /* IGMP generation id */
/*
* Local function definitions.
*/
/* u_char promoted to u_int */
static const char * packet_kind(u_int type, u_int code);
static int igmp_log_level(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(void)
{
struct ip *ip;
recv_buf = malloc(RECV_BUF_SIZE);
send_buf = malloc(RECV_BUF_SIZE);
send_buflen = RECV_BUF_SIZE;
if ((igmp_socket = socket(AF_INET, SOCK_RAW, IPPROTO_IGMP)) < 0)
logit(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);
}
#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 const char *
packet_kind(u_int type, u_int code)
{
switch (type) {
case IGMP_HOST_MEMBERSHIP_QUERY: return "membership query ";
case IGMP_v1_HOST_MEMBERSHIP_REPORT: return "v1 member report ";
case IGMP_v2_HOST_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_QUERY: return "IGMP trace query ";
case IGMP_MTRACE_REPLY: 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(int recvlen)
{
u_int32_t src, dst, group;
struct ip *ip;
struct igmp *igmp;
int ipdatalen, iphdrlen, igmpdatalen;
if (recvlen < (int)sizeof(struct ip)) {
logit(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)
logit(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) {
logit(LOG_WARNING, 0,
"received packet from %s shorter (%u bytes) than hdr+data length (%u+%u)",
inet_fmt(src), recvlen, iphdrlen, ipdatalen);
return;
}
igmp = (struct igmp *)(recv_buf + iphdrlen);
group = igmp->igmp_group.s_addr;
igmpdatalen = ipdatalen - IGMP_MINLEN;
if (igmpdatalen < 0) {
logit(LOG_WARNING, 0,
"received IP data field too short (%u bytes) for IGMP, from %s",
ipdatalen, inet_fmt(src));
return;
}
logit(LOG_DEBUG, 0, "RECV %s from %-15s to %s",
packet_kind(igmp->igmp_type, igmp->igmp_code),
inet_fmt(src), inet_fmt(dst));
switch (igmp->igmp_type) {
case IGMP_HOST_MEMBERSHIP_QUERY:
accept_membership_query(src, dst, group, igmp->igmp_code);
return;
case IGMP_v1_HOST_MEMBERSHIP_REPORT:
case IGMP_v2_HOST_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, (u_char *)(igmp+1),
igmpdatalen);
return;
case DVMRP_INFO_REPLY:
accept_info_reply(src, dst, (u_char *)(igmp+1), igmpdatalen);
return;
default:
logit(LOG_INFO, 0,
"ignoring unknown DVMRP message code %u from %s to %s",
igmp->igmp_code, inet_fmt(src),
inet_fmt(dst));
return;
}
case IGMP_PIM:
return;
case IGMP_MTRACE_REPLY:
return;
case IGMP_MTRACE_QUERY:
accept_mtrace(src, dst, group, (char *)(igmp+1),
igmp->igmp_code, igmpdatalen);
return;
default:
logit(LOG_INFO, 0,
"ignoring unknown IGMP message type %x from %s to %s",
igmp->igmp_type, inet_fmt(src),
inet_fmt(dst));
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(u_int type, u_int code)
{
switch (type) {
case IGMP_MTRACE_REPLY:
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(u_int32_t src, u_int32_t dst, int type, int code, u_int32_t group,
int datalen)
{
struct sockaddr_in sdst;
struct ip *ip;
struct igmp *igmp;
int setloop;
setloop = 0;
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_int16_t *)igmp,
IGMP_MINLEN + datalen);
if (IN_MULTICAST(ntohl(dst))) {
k_set_if(src);
if (type != IGMP_DVMRP) {
setloop = 1;
k_set_loop(TRUE);
}
}
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, ip->ip_len, 0,
(struct sockaddr *)&sdst, sizeof(sdst)) < 0) {
if (errno == ENETDOWN)
check_vif_state();
else
logit(igmp_log_level(type, code), errno,
"sendto to %s on %s",
inet_fmt(dst), inet_fmt(src));
}
if (setloop)
k_set_loop(FALSE);
logit(LOG_DEBUG, 0, "SENT %s from %-15s to %s",
packet_kind(type, code), inet_fmt(src),
inet_fmt(dst));
}
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