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[thirdparty/bird.git] / proto / radv / packets.c
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1/*
2 * BIRD -- RAdv Packet Processing
3 *
4 *
5 * Can be freely distributed and used under the terms of the GNU GPL.
6 */
7
8
9#include <stdlib.h>
10#include "radv.h"
11
12struct radv_ra_packet
13{
14 u8 type;
15 u8 code;
16 u16 checksum;
17 u8 current_hop_limit;
18 u8 flags;
19 u16 router_lifetime;
20 u32 reachable_time;
21 u32 retrans_timer;
22};
23
24#define OPT_RA_MANAGED 0x80
25#define OPT_RA_OTHER_CFG 0x40
26
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27#define OPT_PREFIX 3
28#define OPT_MTU 5
29#define OPT_RDNSS 25
30#define OPT_DNSSL 31
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31
32struct radv_opt_prefix
33{
34 u8 type;
35 u8 length;
36 u8 pxlen;
37 u8 flags;
38 u32 valid_lifetime;
39 u32 preferred_lifetime;
40 u32 reserved;
41 ip_addr prefix;
42};
43
44#define OPT_PX_ONLINK 0x80
45#define OPT_PX_AUTONOMOUS 0x40
46
47struct radv_opt_mtu
48{
49 u8 type;
50 u8 length;
51 u16 reserved;
52 u32 mtu;
53};
54
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55struct radv_opt_rdnss
56{
57 u8 type;
58 u8 length;
59 u16 reserved;
60 u32 lifetime;
61 ip_addr servers[];
62};
63
64struct radv_opt_dnssl
65{
66 u8 type;
67 u8 length;
68 u16 reserved;
69 u32 lifetime;
70 char domain[];
71};
72
73
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74static struct radv_prefix_config default_prefix = {
75 .onlink = 1,
76 .autonomous = 1,
77 .valid_lifetime = DEFAULT_VALID_LIFETIME,
78 .preferred_lifetime = DEFAULT_PREFERRED_LIFETIME
79};
80
fc06fb62 81
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82static struct radv_prefix_config *
83radv_prefix_match(struct radv_iface *ifa, struct ifa *a)
84{
85 struct proto *p = &ifa->ra->p;
86 struct radv_config *cf = (struct radv_config *) (p->cf);
87 struct radv_prefix_config *pc;
88
89 if (a->scope <= SCOPE_LINK)
90 return NULL;
91
92 WALK_LIST(pc, ifa->cf->pref_list)
93 if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
94 return pc;
95
96 WALK_LIST(pc, cf->pref_list)
97 if ((a->pxlen >= pc->pxlen) && ipa_in_net(a->prefix, pc->prefix, pc->pxlen))
98 return pc;
99
100 return &default_prefix;
101}
102
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103static int
104radv_prepare_rdnss(struct radv_iface *ifa, list *rdnss_list, char **buf, char *bufend)
105{
106 struct radv_rdnss_config *rcf = HEAD(*rdnss_list);
107
108 while(NODE_VALID(rcf))
109 {
110 struct radv_rdnss_config *rcf_base = rcf;
111 struct radv_opt_rdnss *op = (void *) *buf;
112 int max_i = (bufend - *buf - sizeof(struct radv_opt_rdnss)) / sizeof(ip_addr);
113 int i = 0;
114
115 if (max_i < 1)
116 goto too_much;
117
118 op->type = OPT_RDNSS;
119 op->reserved = 0;
120
121 if (rcf->lifetime_mult)
122 op->lifetime = htonl(rcf->lifetime_mult * ifa->cf->max_ra_int);
123 else
124 op->lifetime = htonl(rcf->lifetime);
125
126 while(NODE_VALID(rcf) &&
127 (rcf->lifetime == rcf_base->lifetime) &&
128 (rcf->lifetime_mult == rcf_base->lifetime_mult))
129 {
130 if (i >= max_i)
131 goto too_much;
132
133 op->servers[i] = rcf->server;
134 ipa_hton(op->servers[i]);
135 i++;
136
137 rcf = NODE_NEXT(rcf);
138 }
139
140 op->length = 1+2*i;
141 *buf += 8 * op->length;
142 }
143
144 return 0;
145
146 too_much:
147 log(L_WARN "%s: Too many RA options on interface %s",
148 ifa->ra->p.name, ifa->iface->name);
149 return -1;
150}
151
152int
153radv_process_domain(struct radv_dnssl_config *cf)
154{
155 /* Format of domain in search list is <size> <label> <size> <label> ... 0 */
156
157 char *dom = cf->domain;
158 char *dom_end = dom; /* Just to */
159 u8 *dlen_save = &cf->dlen_first;
160 int len;
161
162 while (dom_end)
163 {
164 dom_end = strchr(dom, '.');
165 len = dom_end ? (dom_end - dom) : strlen(dom);
166
167 if (len < 1 || len > 63)
168 return -1;
169
170 *dlen_save = len;
171 dlen_save = (u8 *) dom_end;
172
173 dom += len + 1;
174 }
175
176 len = dom - cf->domain;
177 if (len > 254)
178 return -1;
179
180 cf->dlen_all = len;
181
182 return 0;
183}
184
185static int
186radv_prepare_dnssl(struct radv_iface *ifa, list *dnssl_list, char **buf, char *bufend)
187{
188 struct radv_dnssl_config *dcf = HEAD(*dnssl_list);
189
190 while(NODE_VALID(dcf))
191 {
192 struct radv_dnssl_config *dcf_base = dcf;
193 struct radv_opt_dnssl *op = (void *) *buf;
194 int bsize = bufend - *buf - sizeof(struct radv_opt_dnssl);
195 int bpos = 0;
196
197 if (bsize < 0)
198 goto too_much;
199
200 bsize = bsize & ~7; /* Round down to multiples of 8 */
201
202 op->type = OPT_DNSSL;
203 op->reserved = 0;
204
205 if (dcf->lifetime_mult)
206 op->lifetime = htonl(dcf->lifetime_mult * ifa->cf->max_ra_int);
207 else
208 op->lifetime = htonl(dcf->lifetime);
209
210 while(NODE_VALID(dcf) &&
211 (dcf->lifetime == dcf_base->lifetime) &&
212 (dcf->lifetime_mult == dcf_base->lifetime_mult))
213 {
214 if (bpos + dcf->dlen_all + 1 > bsize)
215 goto too_much;
216
217 op->domain[bpos++] = dcf->dlen_first;
218 memcpy(op->domain + bpos, dcf->domain, dcf->dlen_all);
219 bpos += dcf->dlen_all;
220
221 dcf = NODE_NEXT(dcf);
222 }
223
224 int blen = (bpos + 7) / 8;
225 bzero(op->domain + bpos, 8 * blen - bpos);
226 op->length = 1 + blen;
227 *buf += 8 * op->length;
228 }
229
230 return 0;
231
232 too_much:
233 log(L_WARN "%s: Too many RA options on interface %s",
234 ifa->ra->p.name, ifa->iface->name);
235 return -1;
236}
237
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238static void
239radv_prepare_ra(struct radv_iface *ifa)
240{
241 struct proto_radv *ra = ifa->ra;
fc06fb62 242 struct radv_config *cf = (struct radv_config *) (ra->p.cf);
36da2857 243 struct radv_iface_config *ic = ifa->cf;
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244
245 char *buf = ifa->sk->tbuf;
246 char *bufstart = buf;
247 char *bufend = buf + ifa->sk->tbsize;
248
249 struct radv_ra_packet *pkt = (void *) buf;
250 pkt->type = ICMPV6_RA;
251 pkt->code = 0;
252 pkt->checksum = 0;
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253 pkt->current_hop_limit = ic->current_hop_limit;
254 pkt->flags = (ic->managed ? OPT_RA_MANAGED : 0) |
255 (ic->other_config ? OPT_RA_OTHER_CFG : 0);
256 pkt->router_lifetime = (ra->active || !ic->default_lifetime_sensitive) ?
257 htons(ic->default_lifetime) : 0;
258 pkt->reachable_time = htonl(ic->reachable_time);
259 pkt->retrans_timer = htonl(ic->retrans_timer);
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260 buf += sizeof(*pkt);
261
36da2857 262 if (ic->link_mtu)
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263 {
264 struct radv_opt_mtu *om = (void *) buf;
265 om->type = OPT_MTU;
266 om->length = 1;
267 om->reserved = 0;
36da2857 268 om->mtu = htonl(ic->link_mtu);
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269 buf += sizeof (*om);
270 }
271
272 struct ifa *addr;
273 WALK_LIST(addr, ifa->iface->addrs)
274 {
275 struct radv_prefix_config *pc;
276 pc = radv_prefix_match(ifa, addr);
277
278 if (!pc || pc->skip)
279 continue;
280
281 if (buf + sizeof(struct radv_opt_prefix) > bufend)
282 {
283 log(L_WARN "%s: Too many prefixes on interface %s", ra->p.name, ifa->iface->name);
fc06fb62 284 goto done;
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285 }
286
287 struct radv_opt_prefix *op = (void *) buf;
288 op->type = OPT_PREFIX;
289 op->length = 4;
290 op->pxlen = addr->pxlen;
291 op->flags = (pc->onlink ? OPT_PX_ONLINK : 0) |
292 (pc->autonomous ? OPT_PX_AUTONOMOUS : 0);
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293 op->valid_lifetime = (ra->active || !pc->valid_lifetime_sensitive) ?
294 htonl(pc->valid_lifetime) : 0;
295 op->preferred_lifetime = (ra->active || !pc->preferred_lifetime_sensitive) ?
296 htonl(pc->preferred_lifetime) : 0;
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297 op->reserved = 0;
298 op->prefix = addr->prefix;
299 ipa_hton(op->prefix);
300 buf += sizeof(*op);
301 }
fc06fb62 302
36da2857 303 if (! ic->rdnss_local)
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304 if (radv_prepare_rdnss(ifa, &cf->rdnss_list, &buf, bufend) < 0)
305 goto done;
306
36da2857 307 if (radv_prepare_rdnss(ifa, &ic->rdnss_list, &buf, bufend) < 0)
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308 goto done;
309
36da2857 310 if (! ic->dnssl_local)
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311 if (radv_prepare_dnssl(ifa, &cf->dnssl_list, &buf, bufend) < 0)
312 goto done;
313
36da2857 314 if (radv_prepare_dnssl(ifa, &ic->dnssl_list, &buf, bufend) < 0)
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315 goto done;
316
317 done:
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318 ifa->plen = buf - bufstart;
319}
320
321
322void
323radv_send_ra(struct radv_iface *ifa, int shutdown)
324{
325 struct proto_radv *ra = ifa->ra;
326
327 /* We store prepared RA in tbuf */
328 if (!ifa->plen)
329 radv_prepare_ra(ifa);
330
331 if (shutdown)
332 {
333 /* Modify router lifetime to 0, it is not restored because
334 we suppose that the iface will be removed */
335 struct radv_ra_packet *pkt = (void *) ifa->sk->tbuf;
336 pkt->router_lifetime = 0;
337 }
338
339 RADV_TRACE(D_PACKETS, "Sending RA via %s", ifa->iface->name);
340 sk_send_to(ifa->sk, ifa->plen, AllNodes, 0);
341}
342
343
344static int
345radv_rx_hook(sock *sk, int size)
346{
347 struct radv_iface *ifa = sk->data;
348 struct proto_radv *ra = ifa->ra;
349
350 /* We want just packets from sk->iface */
351 if (sk->lifindex != sk->iface->index)
352 return 1;
353
354 if (ipa_equal(sk->faddr, ifa->addr->ip))
355 return 1;
356
357 if (size < 8)
358 return 1;
359
360 byte *buf = sk->rbuf;
361
362 if (buf[1] != 0)
363 return 1;
364
365 /* Validation is a bit sloppy - Hop Limit is not checked and
366 length of options is ignored for RS and left to later for RA */
367
368 switch (buf[0])
369 {
370 case ICMPV6_RS:
371 RADV_TRACE(D_PACKETS, "Received RS from %I via %s",
372 sk->faddr, ifa->iface->name);
373 radv_iface_notify(ifa, RA_EV_RS);
374 return 1;
375
376 case ICMPV6_RA:
377 RADV_TRACE(D_PACKETS, "Received RA from %I via %s",
378 sk->faddr, ifa->iface->name);
379 /* FIXME - there should be some checking of received RAs, but we just ignore them */
380 return 1;
381
382 default:
383 return 1;
384 }
385}
386
387static void
388radv_tx_hook(sock *sk)
389{
390 struct radv_iface *ifa = sk->data;
391 log(L_WARN "%s: TX hook called", ifa->ra->p.name);
392}
393
394static void
395radv_err_hook(sock *sk, int err)
396{
397 struct radv_iface *ifa = sk->data;
e1afee27 398 log(L_ERR "%s: Socket error on %s: %M", ifa->ra->p.name, ifa->iface->name, err);
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399}
400
401int
402radv_sk_open(struct radv_iface *ifa)
403{
404 sock *sk = sk_new(ifa->ra->p.pool);
405 sk->type = SK_IP;
406 sk->dport = ICMPV6_PROTO;
407 sk->saddr = IPA_NONE;
408
409 sk->ttl = 255; /* Mandatory for Neighbor Discovery packets */
410 sk->rx_hook = radv_rx_hook;
411 sk->tx_hook = radv_tx_hook;
412 sk->err_hook = radv_err_hook;
413 sk->iface = ifa->iface;
414 sk->rbsize = 1024; // bufsize(ifa);
415 sk->tbsize = 1024; // bufsize(ifa);
416 sk->data = ifa;
417 sk->flags = SKF_LADDR_RX;
418
419 if (sk_open(sk) != 0)
420 goto err;
421
422 sk->saddr = ifa->addr->ip;
423
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424 /* We want listen just to ICMPv6 messages of type RS and RA */
425 if (sk_set_icmp_filter(sk, ICMPV6_RS, ICMPV6_RA) < 0)
426 goto err;
427
428 if (sk_setup_multicast(sk) < 0)
429 goto err;
430
431 if (sk_join_group(sk, AllRouters) < 0)
432 goto err;
433
434 ifa->sk = sk;
435 return 1;
436
437 err:
438 rfree(sk);
439 return 0;
440}
441