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
242
243
244
245
246
247
248
249
|
/* $OpenBSD: packet.c,v 1.9 2008/03/15 16:24:58 deraadt Exp $ */
/*
* Copyright (c) 2006 Michele Marchetto <mydecay@openbeer.it>
* Copyright (c) 2004, 2005 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 <sys/uio.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <arpa/inet.h>
#include <net/if_dl.h>
#include <errno.h>
#include <event.h>
#include <stdlib.h>
#include <string.h>
#include "ripd.h"
#include "rip.h"
#include "log.h"
#include "ripe.h"
int rip_hdr_sanity_check(struct rip_hdr *);
struct iface *find_iface(struct ripd_conf *, unsigned int, struct in_addr);
int
gen_rip_hdr(struct buf *buf, u_int8_t command)
{
struct rip_hdr rip_hdr;
bzero(&rip_hdr, sizeof(rip_hdr));
rip_hdr.version = RIP_VERSION;
rip_hdr.command = command;
return (buf_add(buf, &rip_hdr, sizeof(rip_hdr)));
}
/* send and receive packets */
int
send_packet(struct iface *iface, void *pkt, size_t len, struct sockaddr_in *dst)
{
/* set outgoing interface for multicast traffic */
if (IN_MULTICAST(ntohl(dst->sin_addr.s_addr)))
if (if_set_mcast(iface) == -1) {
log_warn("send_packet: error setting multicast "
"interface, %s", iface->name);
return (-1);
}
if (sendto(iface->fd, pkt, len, 0,
(struct sockaddr *)dst, sizeof(*dst)) == -1) {
log_warn("send_packet: error sending packet on interface %s",
iface->name);
return (-1);
}
return (0);
}
void
recv_packet(int fd, short event, void *bula)
{
union {
struct cmsghdr hdr;
char buf[CMSG_SPACE(sizeof(struct sockaddr_dl))];
} cmsgbuf;
struct sockaddr_in src;
struct iovec iov;
struct msghdr msg;
struct cmsghdr *cmsg;
struct sockaddr_dl *dst = NULL;
struct nbr_failed *nbr_failed = NULL;
struct ripd_conf *xconf = bula;
struct iface *iface;
struct rip_hdr *rip_hdr;
struct nbr *nbr;
u_int8_t *buf;
ssize_t r;
u_int16_t len, srcport;
u_int32_t auth_crypt_num = 0;
if (event != EV_READ)
return;
/* setup buffer */
buf = pkt_ptr;
bzero(&msg, sizeof(msg));
iov.iov_base = buf;
iov.iov_len = READ_BUF_SIZE;
msg.msg_name = &src;
msg.msg_namelen = sizeof(src);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
msg.msg_control = &cmsgbuf.buf;
msg.msg_controllen = CMSG_LEN(sizeof(struct sockaddr_dl));
if ((r = recvmsg(fd, &msg, 0)) == -1) {
if (errno != EINTR && errno != EAGAIN)
log_debug("recv_packet: read error: %s",
strerror(errno));
return;
}
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == IPPROTO_IP &&
cmsg->cmsg_type == IP_RECVIF) {
dst = (struct sockaddr_dl *)CMSG_DATA(cmsg);
break;
}
}
if (dst == NULL)
return;
len = (u_int16_t)r;
/* Check the packet is not from one of the local interfaces */
LIST_FOREACH(iface, &xconf->iface_list, entry) {
if (iface->addr.s_addr == src.sin_addr.s_addr)
return;
}
/* find a matching interface */
if ((iface = find_iface(xconf, dst->sdl_index, src.sin_addr)) == NULL) {
log_debug("recv_packet: cannot find a matching interface");
return;
}
srcport = ntohs(src.sin_port);
/* RIP header sanity checks */
if (len < RIP_HDR_LEN) {
log_debug("recv_packet: bad packet size");
return;
}
rip_hdr = (struct rip_hdr *)buf;
if (rip_hdr_sanity_check(rip_hdr) == -1)
return;
nbr = nbr_find_ip(iface, src.sin_addr.s_addr);
if (nbr == NULL && iface->auth_type == AUTH_CRYPT)
nbr_failed = nbr_failed_find(iface, src.sin_addr.s_addr);
/* switch RIP command */
switch (rip_hdr->command) {
case COMMAND_REQUEST:
/* Requests don't create a real neighbor, just a temporary
* one to build the response.
*/
if ((msg.msg_flags & MSG_MCAST) == 0 && srcport == RIP_PORT)
return;
if (nbr == NULL) {
nbr = nbr_new(src.sin_addr.s_addr, iface);
nbr->addr = src.sin_addr;
}
nbr->port = srcport;
nbr_fsm(nbr, NBR_EVT_REQUEST_RCVD);
buf += RIP_HDR_LEN;
len -= RIP_HDR_LEN;
recv_request(iface, nbr, buf, len);
break;
case COMMAND_RESPONSE:
if (srcport != RIP_PORT)
return;
if (auth_validate(&buf, &len, iface, nbr, nbr_failed,
&auth_crypt_num)) {
log_warnx("recv_packet: authentication error, "
"interface %s", iface->name);
return;
}
if (nbr == NULL) {
nbr = nbr_new(src.sin_addr.s_addr, iface);
if (nbr_failed != NULL)
nbr_failed_delete(nbr_failed);
nbr->addr = src.sin_addr;
}
nbr->auth_seq_num = auth_crypt_num;
nbr_fsm(nbr, NBR_EVT_RESPONSE_RCVD);
recv_response(iface, nbr, buf, len);
break;
default:
log_debug("recv_packet: unknown RIP command, interface %s",
iface->name);
}
}
int
rip_hdr_sanity_check(struct rip_hdr *rip_hdr)
{
if (rip_hdr->version != RIP_VERSION) {
log_debug("rip_hdr_sanity_check: invalid RIP version %d",
rip_hdr->version);
return (-1);
}
return (0);
}
struct iface *
find_iface(struct ripd_conf *xconf, unsigned int ifindex, struct in_addr src)
{
struct iface *iface = NULL;
/* returned interface needs to be active */
LIST_FOREACH(iface, &xconf->iface_list, entry) {
if (ifindex != 0 && ifindex == iface->ifindex &&
!iface->passive && (iface->addr.s_addr &
iface->mask.s_addr) == (src.s_addr & iface->mask.s_addr))
/*
* XXX may fail on P2P links because src and dst don't
* have to share a common subnet on the otherhand
* checking something like this will help to support
* multiple networks configured on one interface.
*/
return (iface);
}
return (NULL);
}
|
