1 /* $OpenBSD: packet.c,v 1.22 2023/07/03 09:51:38 claudio Exp $ */
2
3 /*
4 * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #include <sys/types.h>
20 #include <sys/socket.h>
21 #include <sys/uio.h>
22
23 #include <netinet/in.h>
24 #include <netinet/ip.h>
25 #include <netinet/ip6.h>
26 #include <arpa/inet.h>
27
28 #include <errno.h>
29 #include <event.h>
30 #include <limits.h>
31 #include <stdlib.h>
32 #include <string.h>
33
34 #include "ospf6d.h"
35 #include "ospf6.h"
36 #include "log.h"
37 #include "ospfe.h"
38
39 int ip_hdr_sanity_check(const struct ip6_hdr *, u_int16_t);
40 int ospf_hdr_sanity_check(struct ospf_hdr *, u_int16_t,
41 const struct iface *, struct in6_addr *);
42 struct iface *find_iface(struct ospfd_conf *, unsigned int,
43 struct in6_addr *);
44
45 static u_int8_t *recv_buf;
46
47 int
gen_ospf_hdr(struct ibuf * buf,struct iface * iface,u_int8_t type)48 gen_ospf_hdr(struct ibuf *buf, struct iface *iface, u_int8_t type)
49 {
50 struct ospf_hdr ospf_hdr;
51
52 bzero(&ospf_hdr, sizeof(ospf_hdr));
53 ospf_hdr.version = OSPF6_VERSION;
54 ospf_hdr.type = type;
55 ospf_hdr.rtr_id = ospfe_router_id();
56 if (iface->type != IF_TYPE_VIRTUALLINK)
57 ospf_hdr.area_id = iface->area->id.s_addr;
58 ospf_hdr.instance = DEFAULT_INSTANCE_ID;
59 ospf_hdr.zero = 0; /* must be zero */
60
61 return (ibuf_add(buf, &ospf_hdr, sizeof(ospf_hdr)));
62 }
63
64 int
upd_ospf_hdr(struct ibuf * buf,struct iface * iface)65 upd_ospf_hdr(struct ibuf *buf, struct iface *iface)
66 {
67 /* update length */
68 if (ibuf_size(buf) > USHRT_MAX)
69 fatalx("upd_ospf_hdr: resulting ospf packet too big");
70 if (ibuf_set_n16(buf, offsetof(struct ospf_hdr, len),
71 ibuf_size(buf)) == -1)
72 fatalx("upd_ospf_hdr: ibuf_set_n16 failed");
73
74 /* checksum calculated via IPV6_CHECKSUM */
75 if (ibuf_set_n16(buf, offsetof(struct ospf_hdr, chksum), 0) == -1)
76 fatalx("upd_ospf_hdr: ibuf_set_n16 failed");
77
78 return (0);
79 }
80
81 /* send and receive packets */
82 int
send_packet(struct iface * iface,struct ibuf * buf,struct in6_addr * dst)83 send_packet(struct iface *iface, struct ibuf *buf,
84 struct in6_addr *dst)
85 {
86 struct sockaddr_in6 sa6;
87
88 /* setup sockaddr */
89 bzero(&sa6, sizeof(sa6));
90 sa6.sin6_family = AF_INET6;
91 sa6.sin6_len = sizeof(sa6);
92 sa6.sin6_addr = *dst;
93
94 /* don't we all love link local scope and all the needed hacks for it */
95 if (IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MC_LINKLOCAL(dst))
96 sa6.sin6_scope_id = iface->ifindex;
97
98 /* set outgoing interface for multicast traffic */
99 if (IN6_IS_ADDR_MULTICAST(dst))
100 if (if_set_mcast(iface) == -1) {
101 log_warn("send_packet: error setting multicast "
102 "interface, %s", iface->name);
103 return (-1);
104 }
105
106 if (sendto(iface->fd, ibuf_data(buf), ibuf_size(buf), 0,
107 (struct sockaddr *)&sa6, sizeof(sa6)) == -1) {
108 log_warn("send_packet: error sending packet on interface %s",
109 iface->name);
110 return (-1);
111 }
112
113 return (0);
114 }
115
116 void
recv_packet(int fd,short event,void * bula)117 recv_packet(int fd, short event, void *bula)
118 {
119 union {
120 struct cmsghdr hdr;
121 char buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
122 } cmsgbuf;
123 struct msghdr msg;
124 struct iovec iov;
125 struct in6_addr addr, dest;
126 struct sockaddr_in6 src;
127 struct ospfd_conf *xconf = bula;
128 struct ospf_hdr *ospf_hdr;
129 struct iface *iface;
130 struct nbr *nbr = NULL;
131 char *buf;
132 struct cmsghdr *cmsg;
133 ssize_t r;
134 u_int16_t len;
135 int l;
136 unsigned int ifindex = 0;
137
138 if (event != EV_READ)
139 return;
140
141 if (recv_buf == NULL)
142 if ((recv_buf = malloc(READ_BUF_SIZE)) == NULL)
143 fatal(__func__);
144
145 /* setup buffer */
146 bzero(&msg, sizeof(msg));
147 iov.iov_base = buf = recv_buf;
148 iov.iov_len = READ_BUF_SIZE;
149 msg.msg_name = &src;
150 msg.msg_namelen = sizeof(src);
151 msg.msg_iov = &iov;
152 msg.msg_iovlen = 1;
153 msg.msg_control = &cmsgbuf.buf;
154 msg.msg_controllen = sizeof(cmsgbuf.buf);
155
156 if ((r = recvmsg(fd, &msg, 0)) == -1) {
157 if (errno != EAGAIN && errno != EINTR)
158 log_debug("recv_packet: read error: %s",
159 strerror(errno));
160 return;
161 }
162 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
163 cmsg = CMSG_NXTHDR(&msg, cmsg)) {
164 if (cmsg->cmsg_level == IPPROTO_IPV6 &&
165 cmsg->cmsg_type == IPV6_PKTINFO) {
166 ifindex = ((struct in6_pktinfo *)
167 CMSG_DATA(cmsg))->ipi6_ifindex;
168 dest = ((struct in6_pktinfo *)
169 CMSG_DATA(cmsg))->ipi6_addr;
170 break;
171 }
172 }
173
174 /* find a matching interface */
175 if ((iface = find_iface(xconf, ifindex, &src.sin6_addr)) == NULL) {
176 /* XXX add a counter here */
177 return;
178 }
179 /*
180 * Packet needs to be sent to AllSPFRouters or AllDRouters
181 * or to the address of the interface itself.
182 * AllDRouters is only valid for DR and BDR but this is checked later.
183 */
184 inet_pton(AF_INET6, AllSPFRouters, &addr);
185 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) {
186 inet_pton(AF_INET6, AllDRouters, &addr);
187 if (!IN6_ARE_ADDR_EQUAL(&dest, &addr)) {
188 struct iface_addr *ia;
189
190 TAILQ_FOREACH(ia, &iface->ifa_list, entry) {
191 if (IN6_ARE_ADDR_EQUAL(&dest, &ia->addr))
192 break;
193 }
194 if (ia == NULL) {
195 log_debug("recv_packet: packet sent to wrong "
196 "address %s, interface %s",
197 log_in6addr(&dest), iface->name);
198 return;
199 }
200 }
201 }
202
203 len = (u_int16_t)r;
204 /* OSPF header sanity checks */
205 if (len < sizeof(*ospf_hdr)) {
206 log_debug("recv_packet: bad packet size");
207 return;
208 }
209 ospf_hdr = (struct ospf_hdr *)buf;
210
211 if ((l = ospf_hdr_sanity_check(ospf_hdr, len, iface, &dest)) == -1)
212 return;
213
214 nbr = nbr_find_id(iface, ospf_hdr->rtr_id);
215 if (ospf_hdr->type != PACKET_TYPE_HELLO && nbr == NULL) {
216 log_debug("recv_packet: unknown neighbor ID");
217 return;
218 }
219
220 buf += sizeof(*ospf_hdr);
221 len = l - sizeof(*ospf_hdr);
222
223 /* switch OSPF packet type */
224 switch (ospf_hdr->type) {
225 case PACKET_TYPE_HELLO:
226 inet_pton(AF_INET6, AllDRouters, &addr);
227 if (IN6_ARE_ADDR_EQUAL(&dest, &addr)) {
228 log_debug("recv_packet: invalid destination IP "
229 "address");
230 break;
231 }
232
233 recv_hello(iface, &src.sin6_addr, ospf_hdr->rtr_id, buf, len);
234 break;
235 case PACKET_TYPE_DD:
236 recv_db_description(nbr, buf, len);
237 break;
238 case PACKET_TYPE_LS_REQUEST:
239 recv_ls_req(nbr, buf, len);
240 break;
241 case PACKET_TYPE_LS_UPDATE:
242 recv_ls_update(nbr, buf, len);
243 break;
244 case PACKET_TYPE_LS_ACK:
245 recv_ls_ack(nbr, buf, len);
246 break;
247 default:
248 log_debug("recv_packet: unknown OSPF packet type, interface %s",
249 iface->name);
250 }
251 }
252
253 int
ospf_hdr_sanity_check(struct ospf_hdr * ospf_hdr,u_int16_t len,const struct iface * iface,struct in6_addr * dst)254 ospf_hdr_sanity_check(struct ospf_hdr *ospf_hdr, u_int16_t len,
255 const struct iface *iface, struct in6_addr *dst)
256 {
257 struct in6_addr addr;
258 struct in_addr id;
259
260 if (ospf_hdr->version != OSPF6_VERSION) {
261 log_debug("recv_packet: invalid OSPF version %d",
262 ospf_hdr->version);
263 return (-1);
264 }
265
266 if (ntohs(ospf_hdr->len) > len ||
267 len <= sizeof(struct ospf_hdr)) {
268 log_debug("recv_packet: invalid OSPF packet length %d",
269 ntohs(ospf_hdr->len));
270 return (-1);
271 }
272
273 if (iface->type != IF_TYPE_VIRTUALLINK) {
274 if (ospf_hdr->area_id != iface->area->id.s_addr) {
275 id.s_addr = ospf_hdr->area_id;
276 log_debug("recv_packet: invalid area ID %s, "
277 "interface %s", inet_ntoa(id), iface->name);
278 return (-1);
279 }
280 } else {
281 if (ospf_hdr->area_id != 0) {
282 id.s_addr = ospf_hdr->area_id;
283 log_debug("recv_packet: invalid area ID %s, "
284 "interface %s", inet_ntoa(id), iface->name);
285 return (-1);
286 }
287 }
288
289 if (iface->type == IF_TYPE_BROADCAST || iface->type == IF_TYPE_NBMA) {
290 if (inet_pton(AF_INET6, AllDRouters, &addr) == 0)
291 fatalx("recv_packet: inet_pton");
292 if (IN6_ARE_ADDR_EQUAL(dst, &addr) &&
293 (iface->state & IF_STA_DRORBDR) == 0) {
294 log_debug("recv_packet: invalid destination IP in "
295 "state %s, interface %s",
296 if_state_name(iface->state), iface->name);
297 return (-1);
298 }
299 }
300
301 return (ntohs(ospf_hdr->len));
302 }
303
304 struct iface *
find_iface(struct ospfd_conf * xconf,unsigned int ifindex,struct in6_addr * src)305 find_iface(struct ospfd_conf *xconf, unsigned int ifindex, struct in6_addr *src)
306 {
307 struct area *area;
308 struct iface *iface, *match = NULL;
309
310 /*
311 * Returned interface needs to be active.
312 * Virtual-Links have higher precedence so the full interface
313 * list needs to be scanned for possible matches.
314 */
315 LIST_FOREACH(area, &xconf->area_list, entry) {
316 LIST_FOREACH(iface, &area->iface_list, entry) {
317 switch (iface->type) {
318 case IF_TYPE_VIRTUALLINK:
319 if (IN6_ARE_ADDR_EQUAL(src, &iface->dst) &&
320 !(iface->cflags & F_IFACE_PASSIVE))
321 return (iface);
322 break;
323 default:
324 if (ifindex == iface->ifindex &&
325 !(iface->cflags & F_IFACE_PASSIVE))
326 match = iface;
327 break;
328 }
329 }
330 }
331
332 return (match);
333 }
334