1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
|
/* $OpenBSD: igmp.c,v 1.4 2015/12/07 19:14:49 mmcc Exp $ */
/*
* Copyright (c) 2005, 2006 Esben Norby <norby@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/time.h>
#include <stdlib.h>
#include <string.h>
#include <event.h>
#include "igmp.h"
#include "dvmrpd.h"
#include "dvmrp.h"
#include "log.h"
#include "dvmrpe.h"
int igmp_chksum(struct igmp_hdr *);
/* IGMP packet handling */
int
send_igmp_query(struct iface *iface, struct group *group)
{
struct igmp_hdr igmp_hdr;
struct sockaddr_in dst;
struct ibuf *buf;
int ret = 0;
log_debug("send_igmp_query: interface %s", iface->name);
if (iface->passive)
return (0);
if ((buf = ibuf_open(iface->mtu - sizeof(struct ip))) == NULL)
fatal("send_igmp_query");
/* IGMP header */
memset(&igmp_hdr, 0, sizeof(igmp_hdr));
igmp_hdr.type = PKT_TYPE_MEMBER_QUERY;
if (group == NULL) {
/* general query - version is configured */
igmp_hdr.grp_addr = 0;
switch (iface->igmp_version) {
case 1:
break;
case 2:
igmp_hdr.max_resp_time = iface->query_resp_interval;
break;
default:
fatal("send_igmp_query: invalid igmp version");
}
} else {
/* group specific query - only version 2 */
igmp_hdr.grp_addr = group->addr.s_addr;
igmp_hdr.max_resp_time = iface->last_member_query_interval;
}
/* update chksum */
igmp_hdr.chksum = in_cksum(&igmp_hdr, sizeof(igmp_hdr));
ibuf_add(buf, &igmp_hdr, sizeof(igmp_hdr));
/* set destination address */
dst.sin_family = AF_INET;
dst.sin_len = sizeof(struct sockaddr_in);
inet_aton(AllSystems, &dst.sin_addr);
ret = send_packet(iface, buf->buf, buf->wpos, &dst);
ibuf_free(buf);
return (ret);
}
void
recv_igmp_query(struct iface *iface, struct in_addr src, char *buf,
u_int16_t len)
{
struct igmp_hdr igmp_hdr;
struct group *group;
log_debug("recv_igmp_query: interface %s", iface->name);
if (len < sizeof(igmp_hdr)) {
log_debug("recv_igmp_query: invalid IGMP report, interface %s",
iface->name);
return;
}
memcpy(&igmp_hdr, buf, sizeof(igmp_hdr));
iface->recv_query_resp_interval = igmp_hdr.max_resp_time;
/* verify chksum */
if (igmp_chksum(&igmp_hdr) == -1) {
log_debug("recv_igmp_query: invalid chksum, interface %s",
iface->name);
return;
}
if (src.s_addr < iface->addr.s_addr && igmp_hdr.grp_addr == 0) {
/* we received a general query and we lost the election */
if_fsm(iface, IF_EVT_QRECVD);
/* remember who is querier */
iface->querier = src;
return;
}
if (iface->state == IF_STA_NONQUERIER && igmp_hdr.grp_addr != 0) {
/* validate group id */
if (!IN_MULTICAST(ntohl(igmp_hdr.grp_addr))) {
log_debug("recv_igmp_query: invalid group, "
"interface %s", iface->name);
return;
}
if ((group = group_list_add(iface, igmp_hdr.grp_addr))
!= NULL)
group_fsm(group, GRP_EVT_QUERY_RCVD);
}
}
void
recv_igmp_report(struct iface *iface, struct in_addr src, char *buf,
u_int16_t len, u_int8_t type)
{
struct igmp_hdr igmp_hdr;
struct group *group;
log_debug("recv_igmp_report: interface %s", iface->name);
if (len < sizeof(igmp_hdr)) {
log_debug("recv_igmp_report: invalid IGMP report, interface %s",
iface->name);
return;
}
memcpy(&igmp_hdr, buf, sizeof(igmp_hdr));
/* verify chksum */
if (igmp_chksum(&igmp_hdr) == -1) {
log_debug("recv_igmp_report: invalid chksum, interface %s",
iface->name);
return;
}
/* validate group id */
if (!IN_MULTICAST(ntohl(igmp_hdr.grp_addr))) {
log_debug("recv_igmp_report: invalid group, interface %s",
iface->name);
return;
}
if ((group = group_list_add(iface, igmp_hdr.grp_addr)) == NULL)
return;
if (iface->state == IF_STA_QUERIER) {
/* querier */
switch (type) {
case PKT_TYPE_MEMBER_REPORTv1:
group_fsm(group, GRP_EVT_V1_REPORT_RCVD);
break;
case PKT_TYPE_MEMBER_REPORTv2:
group_fsm(group, GRP_EVT_V2_REPORT_RCVD);
break;
default:
fatalx("recv_igmp_report: unknown IGMP report type");
}
} else {
/* non querier */
group_fsm(group, GRP_EVT_REPORT_RCVD);
}
}
void
recv_igmp_leave(struct iface *iface, struct in_addr src, char *buf,
u_int16_t len)
{
struct igmp_hdr igmp_hdr;
struct group *group;
log_debug("recv_igmp_leave: interface %s", iface->name);
if (iface->state != IF_STA_QUERIER)
return;
if (len < sizeof(igmp_hdr)) {
log_debug("recv_igmp_leave: invalid IGMP leave, interface %s",
iface->name);
return;
}
memcpy(&igmp_hdr, buf, sizeof(igmp_hdr));
/* verify chksum */
if (igmp_chksum(&igmp_hdr) == -1) {
log_debug("recv_igmp_leave: invalid chksum, interface %s",
iface->name);
return;
}
/* validate group id */
if (!IN_MULTICAST(ntohl(igmp_hdr.grp_addr))) {
log_debug("recv_igmp_leave: invalid group, interface %s",
iface->name);
return;
}
if ((group = group_list_find(iface, igmp_hdr.grp_addr)) != NULL) {
group_fsm(group, GRP_EVT_LEAVE_RCVD);
}
}
int
igmp_chksum(struct igmp_hdr *igmp_hdr)
{
u_int16_t chksum;
chksum = igmp_hdr->chksum;
igmp_hdr->chksum = 0;
if (chksum != in_cksum(igmp_hdr, sizeof(*igmp_hdr)))
return (-1);
return (0);
}
|
