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937e75d8 OZ |
1 | /* |
2 | * BIRD -- The Babel protocol | |
3 | * | |
4 | * Copyright (c) 2015--2016 Toke Hoiland-Jorgensen | |
5 | * | |
6 | * Can be freely distributed and used under the terms of the GNU GPL. | |
7 | * | |
8 | * This file contains the packet and TLV handling code for the protocol. | |
9 | */ | |
10 | ||
11 | #include "babel.h" | |
12 | ||
13 | ||
14 | struct babel_pkt_header { | |
15 | u8 magic; | |
16 | u8 version; | |
17 | u16 length; | |
18 | } PACKED; | |
19 | ||
20 | struct babel_tlv { | |
21 | u8 type; | |
22 | u8 length; | |
23 | u8 value[0]; | |
24 | } PACKED; | |
25 | ||
26 | struct babel_tlv_ack_req { | |
27 | u8 type; | |
28 | u8 length; | |
29 | u16 reserved; | |
30 | u16 nonce; | |
31 | u16 interval; | |
32 | } PACKED; | |
33 | ||
34 | struct babel_tlv_ack { | |
35 | u8 type; | |
36 | u8 length; | |
37 | u16 nonce; | |
38 | } PACKED; | |
39 | ||
40 | struct babel_tlv_hello { | |
41 | u8 type; | |
42 | u8 length; | |
43 | u16 reserved; | |
44 | u16 seqno; | |
45 | u16 interval; | |
46 | } PACKED; | |
47 | ||
48 | struct babel_tlv_ihu { | |
49 | u8 type; | |
50 | u8 length; | |
51 | u8 ae; | |
52 | u8 reserved; | |
53 | u16 rxcost; | |
54 | u16 interval; | |
55 | u8 addr[0]; | |
56 | } PACKED; | |
57 | ||
58 | struct babel_tlv_router_id { | |
59 | u8 type; | |
60 | u8 length; | |
61 | u16 reserved; | |
62 | u64 router_id; | |
63 | } PACKED; | |
64 | ||
65 | struct babel_tlv_next_hop { | |
66 | u8 type; | |
67 | u8 length; | |
68 | u8 ae; | |
69 | u8 reserved; | |
70 | u8 addr[0]; | |
71 | } PACKED; | |
72 | ||
73 | struct babel_tlv_update { | |
74 | u8 type; | |
75 | u8 length; | |
76 | u8 ae; | |
77 | u8 flags; | |
78 | u8 plen; | |
79 | u8 omitted; | |
80 | u16 interval; | |
81 | u16 seqno; | |
82 | u16 metric; | |
83 | u8 addr[0]; | |
84 | } PACKED; | |
85 | ||
86 | struct babel_tlv_route_request { | |
87 | u8 type; | |
88 | u8 length; | |
89 | u8 ae; | |
90 | u8 plen; | |
91 | u8 addr[0]; | |
92 | } PACKED; | |
93 | ||
94 | struct babel_tlv_seqno_request { | |
95 | u8 type; | |
96 | u8 length; | |
97 | u8 ae; | |
98 | u8 plen; | |
99 | u16 seqno; | |
100 | u8 hop_count; | |
101 | u8 reserved; | |
102 | u64 router_id; | |
103 | u8 addr[0]; | |
104 | } PACKED; | |
105 | ||
106 | ||
107 | #define BABEL_FLAG_DEF_PREFIX 0x80 | |
108 | #define BABEL_FLAG_ROUTER_ID 0x40 | |
109 | ||
110 | ||
111 | struct babel_parse_state { | |
112 | struct babel_proto *proto; | |
113 | struct babel_iface *ifa; | |
114 | ip_addr saddr; | |
115 | ip_addr next_hop; | |
116 | u64 router_id; /* Router ID used in subsequent updates */ | |
117 | u8 def_ip6_prefix[16]; /* Implicit IPv6 prefix in network order */ | |
118 | u8 def_ip4_prefix[4]; /* Implicit IPv4 prefix in network order */ | |
119 | u8 router_id_seen; /* router_id field is valid */ | |
120 | u8 def_ip6_prefix_seen; /* def_ip6_prefix is valid */ | |
121 | u8 def_ip4_prefix_seen; /* def_ip4_prefix is valid */ | |
122 | }; | |
123 | ||
124 | enum parse_result { | |
125 | PARSE_SUCCESS, | |
126 | PARSE_ERROR, | |
127 | PARSE_IGNORE, | |
128 | }; | |
129 | ||
130 | struct babel_write_state { | |
131 | u64 router_id; | |
132 | u8 router_id_seen; | |
133 | // ip_addr next_hop; | |
134 | }; | |
135 | ||
136 | ||
137 | #define DROP(DSC,VAL) do { err_dsc = DSC; err_val = VAL; goto drop; } while(0) | |
138 | #define DROP1(DSC) do { err_dsc = DSC; goto drop; } while(0) | |
139 | #define LOG_PKT(msg, args...) \ | |
140 | log_rl(&p->log_pkt_tbf, L_REMOTE "%s: " msg, p->p.name, args) | |
141 | ||
142 | #define FIRST_TLV(p) ((struct babel_tlv *) (((struct babel_pkt_header *) p) + 1)) | |
143 | #define NEXT_TLV(t) ((struct babel_tlv *) (((byte *) t) + TLV_LENGTH(t))) | |
144 | #define TLV_LENGTH(t) (t->type == BABEL_TLV_PAD1 ? 1 : t->length + sizeof(struct babel_tlv)) | |
145 | #define TLV_OPT_LENGTH(t) (t->length + sizeof(struct babel_tlv) - sizeof(*t)) | |
146 | #define TLV_HDR(tlv,t,l) ({ tlv->type = t; tlv->length = l - sizeof(struct babel_tlv); }) | |
147 | #define TLV_HDR0(tlv,t) TLV_HDR(tlv, t, tlv_data[t].min_length) | |
148 | ||
3e236955 | 149 | #define BYTES(n) ((((uint) n) + 7) / 8) |
937e75d8 OZ |
150 | |
151 | static inline u16 | |
152 | get_time16(const void *p) | |
153 | { | |
154 | u16 v = get_u16(p) / BABEL_TIME_UNITS; | |
155 | return MAX(1, v); | |
156 | } | |
157 | ||
158 | static inline void | |
159 | put_time16(void *p, u16 v) | |
160 | { | |
161 | put_u16(p, v * BABEL_TIME_UNITS); | |
162 | } | |
163 | ||
164 | static inline ip6_addr | |
3e236955 | 165 | get_ip6_px(const void *p, uint plen) |
937e75d8 OZ |
166 | { |
167 | ip6_addr addr = IPA_NONE; | |
3e236955 | 168 | memcpy(&addr, p, BYTES(plen)); |
937e75d8 OZ |
169 | return ip6_ntoh(addr); |
170 | } | |
171 | ||
172 | static inline void | |
3e236955 | 173 | put_ip6_px(void *p, ip6_addr addr, uint plen) |
937e75d8 OZ |
174 | { |
175 | addr = ip6_hton(addr); | |
3e236955 | 176 | memcpy(p, &addr, BYTES(plen)); |
937e75d8 OZ |
177 | } |
178 | ||
179 | static inline ip6_addr | |
180 | get_ip6_ll(const void *p) | |
181 | { | |
182 | return ip6_build(0xfe800000, 0, get_u32(p+0), get_u32(p+4)); | |
183 | } | |
184 | ||
185 | static inline void | |
186 | put_ip6_ll(void *p, ip6_addr addr) | |
187 | { | |
188 | put_u32(p+0, _I2(addr)); | |
189 | put_u32(p+4, _I3(addr)); | |
190 | } | |
191 | ||
192 | ||
193 | /* | |
194 | * TLV read/write functions | |
195 | */ | |
196 | ||
197 | static int babel_read_ack_req(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
198 | static int babel_read_hello(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
199 | static int babel_read_ihu(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
200 | static int babel_read_router_id(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
201 | static int babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
202 | static int babel_read_update(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
203 | static int babel_read_route_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
204 | static int babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state); | |
205 | ||
3e236955 JMM |
206 | static uint babel_write_ack(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); |
207 | static uint babel_write_hello(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); | |
208 | static uint babel_write_ihu(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); | |
209 | static uint babel_write_update(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); | |
210 | static uint babel_write_route_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); | |
211 | static uint babel_write_seqno_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len); | |
937e75d8 OZ |
212 | |
213 | struct babel_tlv_data { | |
214 | u8 min_length; | |
215 | int (*read_tlv)(struct babel_tlv *hdr, union babel_msg *m, struct babel_parse_state *state); | |
3e236955 | 216 | uint (*write_tlv)(struct babel_tlv *hdr, union babel_msg *m, struct babel_write_state *state, uint max_len); |
937e75d8 OZ |
217 | void (*handle_tlv)(union babel_msg *m, struct babel_iface *ifa); |
218 | }; | |
219 | ||
3e236955 | 220 | static const struct babel_tlv_data tlv_data[BABEL_TLV_MAX] = { |
937e75d8 OZ |
221 | [BABEL_TLV_ACK_REQ] = { |
222 | sizeof(struct babel_tlv_ack_req), | |
223 | babel_read_ack_req, | |
224 | NULL, | |
225 | babel_handle_ack_req | |
226 | }, | |
227 | [BABEL_TLV_ACK] = { | |
228 | sizeof(struct babel_tlv_ack), | |
229 | NULL, | |
230 | babel_write_ack, | |
231 | NULL | |
232 | }, | |
233 | [BABEL_TLV_HELLO] = { | |
234 | sizeof(struct babel_tlv_hello), | |
235 | babel_read_hello, | |
236 | babel_write_hello, | |
237 | babel_handle_hello | |
238 | }, | |
239 | [BABEL_TLV_IHU] = { | |
240 | sizeof(struct babel_tlv_ihu), | |
241 | babel_read_ihu, | |
242 | babel_write_ihu, | |
243 | babel_handle_ihu | |
244 | }, | |
245 | [BABEL_TLV_ROUTER_ID] = { | |
246 | sizeof(struct babel_tlv_router_id), | |
247 | babel_read_router_id, | |
248 | NULL, | |
249 | NULL | |
250 | }, | |
251 | [BABEL_TLV_NEXT_HOP] = { | |
252 | sizeof(struct babel_tlv_next_hop), | |
253 | babel_read_next_hop, | |
254 | NULL, | |
255 | NULL | |
256 | }, | |
257 | [BABEL_TLV_UPDATE] = { | |
258 | sizeof(struct babel_tlv_update), | |
259 | babel_read_update, | |
260 | babel_write_update, | |
261 | babel_handle_update | |
262 | }, | |
263 | [BABEL_TLV_ROUTE_REQUEST] = { | |
264 | sizeof(struct babel_tlv_route_request), | |
265 | babel_read_route_request, | |
266 | babel_write_route_request, | |
267 | babel_handle_route_request | |
268 | }, | |
269 | [BABEL_TLV_SEQNO_REQUEST] = { | |
270 | sizeof(struct babel_tlv_seqno_request), | |
271 | babel_read_seqno_request, | |
272 | babel_write_seqno_request, | |
273 | babel_handle_seqno_request | |
274 | }, | |
275 | }; | |
276 | ||
277 | static int | |
278 | babel_read_ack_req(struct babel_tlv *hdr, union babel_msg *m, | |
279 | struct babel_parse_state *state) | |
280 | { | |
281 | struct babel_tlv_ack_req *tlv = (void *) hdr; | |
282 | struct babel_msg_ack_req *msg = &m->ack_req; | |
283 | ||
284 | msg->type = BABEL_TLV_ACK_REQ; | |
285 | msg->nonce = get_u16(&tlv->nonce); | |
286 | msg->interval = get_time16(&tlv->interval); | |
287 | msg->sender = state->saddr; | |
288 | ||
289 | if (!msg->interval) | |
290 | return PARSE_ERROR; | |
291 | ||
292 | return PARSE_SUCCESS; | |
293 | } | |
294 | ||
3e236955 | 295 | static uint |
937e75d8 | 296 | babel_write_ack(struct babel_tlv *hdr, union babel_msg *m, |
3e236955 | 297 | struct babel_write_state *state UNUSED, uint max_len UNUSED) |
937e75d8 OZ |
298 | { |
299 | struct babel_tlv_ack *tlv = (void *) hdr; | |
300 | struct babel_msg_ack *msg = &m->ack; | |
301 | ||
302 | TLV_HDR0(tlv, BABEL_TLV_ACK); | |
303 | put_u16(&tlv->nonce, msg->nonce); | |
304 | ||
305 | return sizeof(struct babel_tlv_ack); | |
306 | } | |
307 | ||
308 | static int | |
309 | babel_read_hello(struct babel_tlv *hdr, union babel_msg *m, | |
310 | struct babel_parse_state *state) | |
311 | { | |
312 | struct babel_tlv_hello *tlv = (void *) hdr; | |
313 | struct babel_msg_hello *msg = &m->hello; | |
314 | ||
315 | msg->type = BABEL_TLV_HELLO; | |
316 | msg->seqno = get_u16(&tlv->seqno); | |
317 | msg->interval = get_time16(&tlv->interval); | |
318 | msg->sender = state->saddr; | |
319 | ||
320 | return PARSE_SUCCESS; | |
321 | } | |
322 | ||
3e236955 | 323 | static uint |
937e75d8 | 324 | babel_write_hello(struct babel_tlv *hdr, union babel_msg *m, |
3e236955 | 325 | struct babel_write_state *state UNUSED, uint max_len UNUSED) |
937e75d8 OZ |
326 | { |
327 | struct babel_tlv_hello *tlv = (void *) hdr; | |
328 | struct babel_msg_hello *msg = &m->hello; | |
329 | ||
330 | TLV_HDR0(tlv, BABEL_TLV_HELLO); | |
331 | put_u16(&tlv->seqno, msg->seqno); | |
332 | put_time16(&tlv->interval, msg->interval); | |
333 | ||
334 | return sizeof(struct babel_tlv_hello); | |
335 | } | |
336 | ||
337 | static int | |
338 | babel_read_ihu(struct babel_tlv *hdr, union babel_msg *m, | |
339 | struct babel_parse_state *state) | |
340 | { | |
341 | struct babel_tlv_ihu *tlv = (void *) hdr; | |
342 | struct babel_msg_ihu *msg = &m->ihu; | |
343 | ||
344 | msg->type = BABEL_TLV_IHU; | |
345 | msg->ae = tlv->ae; | |
346 | msg->rxcost = get_u16(&tlv->rxcost); | |
347 | msg->interval = get_time16(&tlv->interval); | |
348 | msg->addr = IPA_NONE; | |
349 | msg->sender = state->saddr; | |
350 | ||
351 | if (msg->ae >= BABEL_AE_MAX) | |
352 | return PARSE_IGNORE; | |
353 | ||
354 | // We handle link-local IPs. In every other case, the addr field will be 0 but | |
355 | // validation will succeed. The handler takes care of these cases. | |
356 | if (msg->ae == BABEL_AE_IP6_LL) | |
357 | { | |
358 | if (TLV_OPT_LENGTH(tlv) < 8) | |
359 | return PARSE_ERROR; | |
360 | ||
361 | msg->addr = ipa_from_ip6(get_ip6_ll(&tlv->addr)); | |
362 | } | |
363 | ||
364 | return PARSE_SUCCESS; | |
365 | } | |
366 | ||
3e236955 | 367 | static uint |
937e75d8 | 368 | babel_write_ihu(struct babel_tlv *hdr, union babel_msg *m, |
3e236955 | 369 | struct babel_write_state *state UNUSED, uint max_len) |
937e75d8 OZ |
370 | { |
371 | struct babel_tlv_ihu *tlv = (void *) hdr; | |
372 | struct babel_msg_ihu *msg = &m->ihu; | |
373 | ||
374 | if (ipa_is_link_local(msg->addr) && max_len < sizeof(struct babel_tlv_ihu) + 8) | |
375 | return 0; | |
376 | ||
377 | TLV_HDR0(tlv, BABEL_TLV_IHU); | |
378 | put_u16(&tlv->rxcost, msg->rxcost); | |
379 | put_time16(&tlv->interval, msg->interval); | |
380 | ||
381 | if (!ipa_is_link_local(msg->addr)) | |
382 | { | |
383 | tlv->ae = BABEL_AE_WILDCARD; | |
384 | return sizeof(struct babel_tlv_ihu); | |
385 | } | |
386 | put_ip6_ll(&tlv->addr, msg->addr); | |
387 | tlv->ae = BABEL_AE_IP6_LL; | |
388 | hdr->length += 8; | |
389 | return sizeof(struct babel_tlv_ihu) + 8; | |
390 | } | |
391 | ||
392 | static int | |
393 | babel_read_router_id(struct babel_tlv *hdr, union babel_msg *m UNUSED, | |
394 | struct babel_parse_state *state) | |
395 | { | |
396 | struct babel_tlv_router_id *tlv = (void *) hdr; | |
397 | ||
398 | state->router_id = get_u64(&tlv->router_id); | |
399 | state->router_id_seen = 1; | |
400 | ||
401 | return PARSE_IGNORE; | |
402 | } | |
403 | ||
404 | /* This is called directly from babel_write_update() */ | |
3e236955 | 405 | static uint |
937e75d8 | 406 | babel_write_router_id(struct babel_tlv *hdr, u64 router_id, |
3e236955 | 407 | struct babel_write_state *state, uint max_len UNUSED) |
937e75d8 OZ |
408 | { |
409 | struct babel_tlv_router_id *tlv = (void *) hdr; | |
410 | ||
411 | /* We still assume that first min_length bytes are available and zeroed */ | |
412 | ||
413 | TLV_HDR0(tlv, BABEL_TLV_ROUTER_ID); | |
414 | put_u64(&tlv->router_id, router_id); | |
415 | ||
416 | state->router_id = router_id; | |
417 | state->router_id_seen = 1; | |
418 | ||
419 | return sizeof(struct babel_tlv_router_id); | |
420 | } | |
421 | ||
422 | static int | |
423 | babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *m UNUSED, | |
424 | struct babel_parse_state *state) | |
425 | { | |
426 | struct babel_tlv_next_hop *tlv = (void *) hdr; | |
427 | ||
428 | switch (tlv->ae) | |
429 | { | |
430 | case BABEL_AE_WILDCARD: | |
431 | return PARSE_ERROR; | |
432 | ||
433 | case BABEL_AE_IP4: | |
434 | /* TODO */ | |
435 | return PARSE_IGNORE; | |
436 | ||
437 | case BABEL_AE_IP6: | |
438 | if (TLV_OPT_LENGTH(tlv) < sizeof(ip6_addr)) | |
439 | return PARSE_ERROR; | |
440 | ||
441 | state->next_hop = ipa_from_ip6(get_ip6(&tlv->addr)); | |
442 | return PARSE_IGNORE; | |
443 | ||
444 | case BABEL_AE_IP6_LL: | |
445 | if (TLV_OPT_LENGTH(tlv) < 8) | |
446 | return PARSE_ERROR; | |
447 | ||
448 | state->next_hop = ipa_from_ip6(get_ip6_ll(&tlv->addr)); | |
449 | return PARSE_IGNORE; | |
450 | ||
451 | default: | |
452 | return PARSE_IGNORE; | |
453 | } | |
454 | ||
455 | return PARSE_IGNORE; | |
456 | } | |
457 | ||
458 | static int | |
459 | babel_read_update(struct babel_tlv *hdr, union babel_msg *m, | |
460 | struct babel_parse_state *state) | |
461 | { | |
462 | struct babel_tlv_update *tlv = (void *) hdr; | |
463 | struct babel_msg_update *msg = &m->update; | |
464 | ||
465 | msg->type = BABEL_TLV_UPDATE; | |
937e75d8 OZ |
466 | msg->interval = get_time16(&tlv->interval); |
467 | msg->seqno = get_u16(&tlv->seqno); | |
468 | msg->metric = get_u16(&tlv->metric); | |
469 | ||
470 | /* Length of received prefix data without omitted part */ | |
3e236955 | 471 | int len = BYTES(tlv->plen) - (int) tlv->omitted; |
937e75d8 OZ |
472 | u8 buf[16] = {}; |
473 | ||
3e236955 | 474 | if ((len < 0) || ((uint) len > TLV_OPT_LENGTH(tlv))) |
937e75d8 OZ |
475 | return PARSE_ERROR; |
476 | ||
477 | switch (tlv->ae) | |
478 | { | |
479 | case BABEL_AE_WILDCARD: | |
480 | if (tlv->plen > 0) | |
481 | return PARSE_ERROR; | |
482 | ||
5d6ca220 | 483 | msg->wildcard = 1; |
937e75d8 OZ |
484 | break; |
485 | ||
486 | case BABEL_AE_IP4: | |
487 | /* TODO */ | |
488 | return PARSE_IGNORE; | |
489 | ||
490 | case BABEL_AE_IP6: | |
491 | if (tlv->plen > MAX_PREFIX_LENGTH) | |
492 | return PARSE_ERROR; | |
493 | ||
494 | /* Cannot omit data if there is no saved prefix */ | |
495 | if (tlv->omitted && !state->def_ip6_prefix_seen) | |
496 | return PARSE_ERROR; | |
497 | ||
498 | /* Merge saved prefix and received prefix parts */ | |
499 | memcpy(buf, state->def_ip6_prefix, tlv->omitted); | |
500 | memcpy(buf + tlv->omitted, tlv->addr, len); | |
501 | ||
502 | msg->plen = tlv->plen; | |
503 | msg->prefix = ipa_from_ip6(get_ip6(buf)); | |
504 | ||
505 | if (tlv->flags & BABEL_FLAG_DEF_PREFIX) | |
506 | { | |
507 | put_ip6(state->def_ip6_prefix, msg->prefix); | |
508 | state->def_ip6_prefix_seen = 1; | |
509 | } | |
510 | ||
511 | if (tlv->flags & BABEL_FLAG_ROUTER_ID) | |
512 | { | |
513 | state->router_id = ((u64) _I2(msg->prefix)) << 32 | _I3(msg->prefix); | |
514 | state->router_id_seen = 1; | |
515 | } | |
516 | break; | |
517 | ||
518 | case BABEL_AE_IP6_LL: | |
519 | /* ??? */ | |
520 | return PARSE_IGNORE; | |
521 | ||
522 | default: | |
523 | return PARSE_IGNORE; | |
524 | } | |
525 | ||
ecae2f43 OZ |
526 | /* Update must have Router ID, unless it is retraction */ |
527 | if (!state->router_id_seen && (msg->metric != BABEL_INFINITY)) | |
937e75d8 OZ |
528 | { |
529 | DBG("Babel: No router ID seen before update\n"); | |
530 | return PARSE_ERROR; | |
531 | } | |
532 | ||
533 | msg->router_id = state->router_id; | |
534 | msg->next_hop = state->next_hop; | |
535 | msg->sender = state->saddr; | |
536 | ||
537 | return PARSE_SUCCESS; | |
538 | } | |
539 | ||
3e236955 | 540 | static uint |
937e75d8 | 541 | babel_write_update(struct babel_tlv *hdr, union babel_msg *m, |
3e236955 | 542 | struct babel_write_state *state, uint max_len) |
937e75d8 OZ |
543 | { |
544 | struct babel_tlv_update *tlv = (void *) hdr; | |
545 | struct babel_msg_update *msg = &m->update; | |
3e236955 | 546 | uint len0 = 0; |
937e75d8 OZ |
547 | |
548 | /* | |
549 | * When needed, we write Router-ID TLV before Update TLV and return size of | |
550 | * both of them. There is enough space for the Router-ID TLV, because | |
551 | * sizeof(struct babel_tlv_router_id) == sizeof(struct babel_tlv_update). | |
5d6ca220 OZ |
552 | * |
553 | * Router ID is not used for retractions, so do not us it in such case. | |
937e75d8 | 554 | */ |
5d6ca220 OZ |
555 | if ((msg->metric < BABEL_INFINITY) && |
556 | (!state->router_id_seen || (msg->router_id != state->router_id))) | |
937e75d8 OZ |
557 | { |
558 | len0 = babel_write_router_id(hdr, msg->router_id, state, max_len); | |
559 | tlv = (struct babel_tlv_update *) NEXT_TLV(tlv); | |
560 | } | |
561 | ||
3e236955 | 562 | uint len = sizeof(struct babel_tlv_update) + BYTES(msg->plen); |
937e75d8 OZ |
563 | |
564 | if (len0 + len > max_len) | |
565 | return 0; | |
566 | ||
567 | memset(tlv, 0, sizeof(struct babel_tlv_update)); | |
568 | TLV_HDR(tlv, BABEL_TLV_UPDATE, len); | |
5d6ca220 OZ |
569 | |
570 | if (msg->wildcard) | |
571 | { | |
572 | tlv->ae = BABEL_AE_WILDCARD; | |
573 | tlv->plen = 0; | |
574 | } | |
575 | else | |
576 | { | |
577 | tlv->ae = BABEL_AE_IP6; | |
578 | tlv->plen = msg->plen; | |
579 | put_ip6_px(tlv->addr, msg->prefix, msg->plen); | |
580 | } | |
581 | ||
937e75d8 OZ |
582 | put_time16(&tlv->interval, msg->interval); |
583 | put_u16(&tlv->seqno, msg->seqno); | |
584 | put_u16(&tlv->metric, msg->metric); | |
937e75d8 OZ |
585 | |
586 | return len0 + len; | |
587 | } | |
588 | ||
589 | static int | |
590 | babel_read_route_request(struct babel_tlv *hdr, union babel_msg *m, | |
3e236955 | 591 | struct babel_parse_state *state UNUSED) |
937e75d8 OZ |
592 | { |
593 | struct babel_tlv_route_request *tlv = (void *) hdr; | |
594 | struct babel_msg_route_request *msg = &m->route_request; | |
595 | ||
596 | msg->type = BABEL_TLV_ROUTE_REQUEST; | |
597 | ||
598 | switch (tlv->ae) | |
599 | { | |
600 | case BABEL_AE_WILDCARD: | |
601 | /* Wildcard requests must have plen 0 */ | |
602 | if (tlv->plen > 0) | |
603 | return PARSE_ERROR; | |
604 | ||
605 | msg->full = 1; | |
606 | return PARSE_SUCCESS; | |
607 | ||
608 | case BABEL_AE_IP4: | |
609 | /* TODO */ | |
610 | return PARSE_IGNORE; | |
611 | ||
612 | case BABEL_AE_IP6: | |
613 | if (tlv->plen > MAX_PREFIX_LENGTH) | |
614 | return PARSE_ERROR; | |
615 | ||
3e236955 | 616 | if (TLV_OPT_LENGTH(tlv) < BYTES(tlv->plen)) |
937e75d8 OZ |
617 | return PARSE_ERROR; |
618 | ||
619 | msg->plen = tlv->plen; | |
620 | msg->prefix = get_ip6_px(tlv->addr, tlv->plen); | |
621 | return PARSE_SUCCESS; | |
622 | ||
623 | case BABEL_AE_IP6_LL: | |
624 | return PARSE_ERROR; | |
625 | ||
626 | default: | |
627 | return PARSE_IGNORE; | |
628 | } | |
629 | ||
630 | return PARSE_IGNORE; | |
631 | } | |
632 | ||
3e236955 | 633 | static uint |
937e75d8 | 634 | babel_write_route_request(struct babel_tlv *hdr, union babel_msg *m, |
3e236955 | 635 | struct babel_write_state *state UNUSED, uint max_len) |
937e75d8 OZ |
636 | { |
637 | struct babel_tlv_route_request *tlv = (void *) hdr; | |
638 | struct babel_msg_route_request *msg = &m->route_request; | |
639 | ||
3e236955 | 640 | uint len = sizeof(struct babel_tlv_route_request) + BYTES(msg->plen); |
937e75d8 OZ |
641 | |
642 | if (len > max_len) | |
643 | return 0; | |
644 | ||
645 | TLV_HDR(tlv, BABEL_TLV_ROUTE_REQUEST, len); | |
646 | ||
647 | if (msg->full) | |
648 | { | |
649 | tlv->ae = BABEL_AE_WILDCARD; | |
650 | tlv->plen = 0; | |
651 | } | |
652 | else | |
653 | { | |
654 | tlv->ae = BABEL_AE_IP6; | |
655 | tlv->plen = msg->plen; | |
656 | put_ip6_px(tlv->addr, msg->prefix, msg->plen); | |
657 | } | |
658 | ||
659 | return len; | |
660 | } | |
661 | ||
662 | static int | |
663 | babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *m, | |
664 | struct babel_parse_state *state) | |
665 | { | |
666 | struct babel_tlv_seqno_request *tlv = (void *) hdr; | |
667 | struct babel_msg_seqno_request *msg = &m->seqno_request; | |
668 | ||
669 | msg->type = BABEL_TLV_SEQNO_REQUEST; | |
670 | msg->seqno = get_u16(&tlv->seqno); | |
671 | msg->hop_count = tlv->hop_count; | |
672 | msg->router_id = get_u64(&tlv->router_id); | |
673 | msg->sender = state->saddr; | |
674 | ||
675 | if (tlv->hop_count == 0) | |
676 | return PARSE_ERROR; | |
677 | ||
678 | switch (tlv->ae) | |
679 | { | |
680 | case BABEL_AE_WILDCARD: | |
681 | return PARSE_ERROR; | |
682 | ||
683 | case BABEL_AE_IP4: | |
684 | /* TODO */ | |
685 | return PARSE_IGNORE; | |
686 | ||
687 | case BABEL_AE_IP6: | |
688 | if (tlv->plen > MAX_PREFIX_LENGTH) | |
689 | return PARSE_ERROR; | |
690 | ||
3e236955 | 691 | if (TLV_OPT_LENGTH(tlv) < BYTES(tlv->plen)) |
937e75d8 OZ |
692 | return PARSE_ERROR; |
693 | ||
694 | msg->plen = tlv->plen; | |
695 | msg->prefix = get_ip6_px(tlv->addr, tlv->plen); | |
696 | return PARSE_SUCCESS; | |
697 | ||
698 | case BABEL_AE_IP6_LL: | |
699 | return PARSE_ERROR; | |
700 | ||
701 | default: | |
702 | return PARSE_IGNORE; | |
703 | } | |
704 | ||
705 | return PARSE_IGNORE; | |
706 | } | |
707 | ||
3e236955 | 708 | static uint |
937e75d8 | 709 | babel_write_seqno_request(struct babel_tlv *hdr, union babel_msg *m, |
3e236955 | 710 | struct babel_write_state *state UNUSED, uint max_len) |
937e75d8 OZ |
711 | { |
712 | struct babel_tlv_seqno_request *tlv = (void *) hdr; | |
713 | struct babel_msg_seqno_request *msg = &m->seqno_request; | |
714 | ||
3e236955 | 715 | uint len = sizeof(struct babel_tlv_seqno_request) + BYTES(msg->plen); |
937e75d8 OZ |
716 | |
717 | if (len > max_len) | |
718 | return 0; | |
719 | ||
720 | TLV_HDR(tlv, BABEL_TLV_SEQNO_REQUEST, len); | |
721 | tlv->ae = BABEL_AE_IP6; | |
722 | tlv->plen = msg->plen; | |
723 | put_u16(&tlv->seqno, msg->seqno); | |
724 | tlv->hop_count = msg->hop_count; | |
725 | put_u64(&tlv->router_id, msg->router_id); | |
726 | put_ip6_px(tlv->addr, msg->prefix, msg->plen); | |
727 | ||
728 | return len; | |
729 | } | |
730 | ||
731 | static inline int | |
732 | babel_read_tlv(struct babel_tlv *hdr, | |
733 | union babel_msg *msg, | |
734 | struct babel_parse_state *state) | |
735 | { | |
736 | if ((hdr->type <= BABEL_TLV_PADN) || | |
737 | (hdr->type >= BABEL_TLV_MAX) || | |
738 | !tlv_data[hdr->type].read_tlv) | |
739 | return PARSE_IGNORE; | |
740 | ||
741 | if (TLV_LENGTH(hdr) < tlv_data[hdr->type].min_length) | |
742 | return PARSE_ERROR; | |
743 | ||
744 | memset(msg, 0, sizeof(*msg)); | |
745 | return tlv_data[hdr->type].read_tlv(hdr, msg, state); | |
746 | } | |
747 | ||
3e236955 | 748 | static uint |
937e75d8 OZ |
749 | babel_write_tlv(struct babel_tlv *hdr, |
750 | union babel_msg *msg, | |
751 | struct babel_write_state *state, | |
3e236955 | 752 | uint max_len) |
937e75d8 OZ |
753 | { |
754 | if ((msg->type <= BABEL_TLV_PADN) || | |
755 | (msg->type >= BABEL_TLV_MAX) || | |
756 | !tlv_data[msg->type].write_tlv) | |
757 | return 0; | |
758 | ||
759 | if (tlv_data[msg->type].min_length > max_len) | |
760 | return 0; | |
761 | ||
762 | memset(hdr, 0, tlv_data[msg->type].min_length); | |
763 | return tlv_data[msg->type].write_tlv(hdr, msg, state, max_len); | |
764 | } | |
765 | ||
766 | ||
767 | /* | |
768 | * Packet RX/TX functions | |
769 | */ | |
770 | ||
771 | static int | |
772 | babel_send_to(struct babel_iface *ifa, ip_addr dest) | |
773 | { | |
774 | sock *sk = ifa->sk; | |
775 | struct babel_pkt_header *hdr = (void *) sk->tbuf; | |
776 | int len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header); | |
777 | ||
778 | DBG("Babel: Sending %d bytes to %I\n", len, dest); | |
779 | return sk_send_to(sk, len, dest, 0); | |
780 | } | |
781 | ||
782 | /** | |
783 | * babel_write_queue - Write a TLV queue to a transmission buffer | |
784 | * @ifa: Interface holding the transmission buffer | |
785 | * @queue: TLV queue to write (containing internal-format TLVs) | |
786 | * | |
787 | * This function writes a packet to the interface transmission buffer with as | |
788 | * many TLVs from the &queue as will fit in the buffer. It returns the number of | |
789 | * bytes written (NOT counting the packet header). The function is called by | |
790 | * babel_send_queue() and babel_send_unicast() to construct packets for | |
791 | * transmission, and uses per-TLV helper functions to convert the | |
792 | * internal-format TLVs to their wire representations. | |
793 | * | |
794 | * The TLVs in the queue are freed after they are written to the buffer. | |
795 | */ | |
3e236955 | 796 | static uint |
937e75d8 OZ |
797 | babel_write_queue(struct babel_iface *ifa, list *queue) |
798 | { | |
799 | struct babel_proto *p = ifa->proto; | |
800 | struct babel_write_state state = {}; | |
801 | ||
802 | if (EMPTY_LIST(*queue)) | |
803 | return 0; | |
804 | ||
805 | byte *pos = ifa->sk->tbuf; | |
806 | byte *end = pos + ifa->tx_length; | |
807 | ||
808 | struct babel_pkt_header *pkt = (void *) pos; | |
809 | pkt->magic = BABEL_MAGIC; | |
810 | pkt->version = BABEL_VERSION; | |
811 | pkt->length = 0; | |
812 | pos += sizeof(struct babel_pkt_header); | |
813 | ||
814 | struct babel_msg_node *msg; | |
815 | WALK_LIST_FIRST(msg, *queue) | |
816 | { | |
3e236955 JMM |
817 | if (pos >= end) |
818 | break; | |
819 | ||
937e75d8 OZ |
820 | int len = babel_write_tlv((struct babel_tlv *) pos, &msg->msg, &state, end - pos); |
821 | ||
822 | if (!len) | |
823 | break; | |
824 | ||
825 | pos += len; | |
826 | rem_node(NODE msg); | |
827 | sl_free(p->msg_slab, msg); | |
828 | } | |
829 | ||
3e236955 | 830 | uint plen = pos - (byte *) pkt; |
937e75d8 OZ |
831 | put_u16(&pkt->length, plen - sizeof(struct babel_pkt_header)); |
832 | ||
833 | return plen; | |
834 | } | |
835 | ||
836 | void | |
837 | babel_send_queue(void *arg) | |
838 | { | |
839 | struct babel_iface *ifa = arg; | |
840 | while ((babel_write_queue(ifa, &ifa->msg_queue) > 0) && | |
841 | (babel_send_to(ifa, IP6_BABEL_ROUTERS) > 0)); | |
842 | } | |
843 | ||
844 | static inline void | |
845 | babel_kick_queue(struct babel_iface *ifa) | |
846 | { | |
847 | /* | |
848 | * Only schedule send event if there is not already data in the socket buffer. | |
849 | * Otherwise we may overwrite the data already in the buffer. | |
850 | */ | |
851 | ||
852 | if ((ifa->sk->tpos == ifa->sk->tbuf) && !ev_active(ifa->send_event)) | |
853 | ev_schedule(ifa->send_event); | |
854 | } | |
855 | ||
856 | /** | |
857 | * babel_send_unicast - send a single TLV via unicast to a destination | |
858 | * @msg: TLV to send | |
859 | * @ifa: Interface to send via | |
860 | * @dest: Destination of the TLV | |
861 | * | |
862 | * This function is used to send a single TLV via unicast to a designated | |
863 | * receiver. This is used for replying to certain incoming requests, and for | |
864 | * sending unicast requests to refresh routes before they expire. | |
865 | */ | |
866 | void | |
867 | babel_send_unicast(union babel_msg *msg, struct babel_iface *ifa, ip_addr dest) | |
868 | { | |
869 | struct babel_proto *p = ifa->proto; | |
870 | struct babel_msg_node *msgn = sl_alloc(p->msg_slab); | |
871 | list queue; | |
872 | ||
873 | msgn->msg = *msg; | |
874 | init_list(&queue); | |
875 | add_tail(&queue, NODE msgn); | |
876 | babel_write_queue(ifa, &queue); | |
877 | babel_send_to(ifa, dest); | |
878 | ||
879 | /* We could overwrite waiting packet here, we may have to kick TX queue */ | |
880 | if (!EMPTY_LIST(ifa->msg_queue)) | |
881 | babel_kick_queue(ifa); | |
882 | } | |
883 | ||
884 | /** | |
885 | * babel_enqueue - enqueue a TLV for transmission on an interface | |
886 | * @msg: TLV to enqueue (in internal TLV format) | |
887 | * @ifa: Interface to enqueue to | |
888 | * | |
889 | * This function is called to enqueue a TLV for subsequent transmission on an | |
890 | * interface. The transmission event is triggered whenever a TLV is enqueued; | |
891 | * this ensures that TLVs will be transmitted in a timely manner, but that TLVs | |
892 | * which are enqueued in rapid succession can be transmitted together in one | |
893 | * packet. | |
894 | */ | |
895 | void | |
896 | babel_enqueue(union babel_msg *msg, struct babel_iface *ifa) | |
897 | { | |
898 | struct babel_proto *p = ifa->proto; | |
899 | struct babel_msg_node *msgn = sl_alloc(p->msg_slab); | |
900 | msgn->msg = *msg; | |
901 | add_tail(&ifa->msg_queue, NODE msgn); | |
902 | babel_kick_queue(ifa); | |
903 | } | |
904 | ||
905 | /** | |
906 | * babel_process_packet - process incoming data packet | |
907 | * @pkt: Pointer to the packet data | |
908 | * @len: Length of received packet | |
909 | * @saddr: Address of packet sender | |
910 | * @ifa: Interface packet was received on. | |
911 | * | |
912 | * This function is the main processing hook of incoming Babel packets. It | |
913 | * checks that the packet header is well-formed, then processes the TLVs | |
914 | * contained in the packet. This is done in two passes: First all TLVs are | |
915 | * parsed into the internal TLV format. If a TLV parser fails, processing of the | |
916 | * rest of the packet is aborted. | |
917 | * | |
918 | * After the parsing step, the TLV handlers are called for each parsed TLV in | |
919 | * order. | |
920 | */ | |
921 | static void | |
922 | babel_process_packet(struct babel_pkt_header *pkt, int len, | |
923 | ip_addr saddr, struct babel_iface *ifa) | |
924 | { | |
925 | struct babel_proto *p = ifa->proto; | |
926 | struct babel_tlv *tlv; | |
927 | struct babel_msg_node *msg; | |
928 | list msgs; | |
929 | int res; | |
930 | ||
931 | int plen = sizeof(struct babel_pkt_header) + get_u16(&pkt->length); | |
932 | byte *pos; | |
933 | byte *end = (byte *)pkt + plen; | |
934 | ||
935 | struct babel_parse_state state = { | |
936 | .proto = p, | |
937 | .ifa = ifa, | |
938 | .saddr = saddr, | |
939 | .next_hop = saddr, | |
940 | }; | |
941 | ||
942 | if ((pkt->magic != BABEL_MAGIC) || (pkt->version != BABEL_VERSION)) | |
943 | { | |
944 | TRACE(D_PACKETS, "Strange packet from %I via %s - magic %d version %d", | |
945 | saddr, ifa->iface->name, pkt->magic, pkt->version); | |
946 | return; | |
947 | } | |
948 | ||
949 | if (plen > len) | |
950 | { | |
951 | LOG_PKT("Bad packet from %I via %s - %s (%u)", | |
952 | saddr, ifa->iface->name, "length mismatch", plen); | |
953 | return; | |
954 | } | |
955 | ||
956 | TRACE(D_PACKETS, "Packet received from %I via %s", | |
957 | saddr, ifa->iface->name); | |
958 | ||
959 | init_list(&msgs); | |
960 | ||
961 | /* First pass through the packet TLV by TLV, parsing each into internal data | |
962 | structures. */ | |
963 | for (tlv = FIRST_TLV(pkt); | |
964 | (byte *)tlv < end; | |
965 | tlv = NEXT_TLV(tlv)) | |
966 | { | |
967 | /* Ugly special case */ | |
968 | if (tlv->type == BABEL_TLV_PAD1) | |
969 | continue; | |
970 | ||
971 | /* The end of the common TLV header */ | |
972 | pos = (byte *)tlv + sizeof(struct babel_tlv); | |
973 | if ((pos > end) || (pos + tlv->length > end)) | |
974 | { | |
975 | LOG_PKT("Bad TLV from %I via %s type %d pos %d - framing error", | |
976 | saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt); | |
977 | break; | |
978 | } | |
979 | ||
980 | msg = sl_alloc(p->msg_slab); | |
981 | res = babel_read_tlv(tlv, &msg->msg, &state); | |
982 | if (res == PARSE_SUCCESS) | |
983 | { | |
984 | add_tail(&msgs, NODE msg); | |
985 | } | |
986 | else if (res == PARSE_IGNORE) | |
987 | { | |
988 | DBG("Babel: Ignoring TLV of type %d\n", tlv->type); | |
989 | sl_free(p->msg_slab, msg); | |
990 | } | |
991 | else /* PARSE_ERROR */ | |
992 | { | |
993 | LOG_PKT("Bad TLV from %I via %s type %d pos %d - parse error", | |
994 | saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt); | |
995 | sl_free(p->msg_slab, msg); | |
996 | break; | |
997 | } | |
998 | } | |
999 | ||
1000 | /* Parsing done, handle all parsed TLVs */ | |
1001 | WALK_LIST_FIRST(msg, msgs) | |
1002 | { | |
1003 | if (tlv_data[msg->msg.type].handle_tlv) | |
1004 | tlv_data[msg->msg.type].handle_tlv(&msg->msg, ifa); | |
1005 | rem_node(NODE msg); | |
1006 | sl_free(p->msg_slab, msg); | |
1007 | } | |
1008 | } | |
1009 | ||
1010 | static void | |
1011 | babel_err_hook(sock *sk, int err) | |
1012 | { | |
1013 | struct babel_iface *ifa = sk->data; | |
1014 | struct babel_proto *p = ifa->proto; | |
1015 | ||
1016 | log(L_ERR "%s: Socket error on %s: %M", p->p.name, ifa->iface->name, err); | |
1017 | /* FIXME: Drop queued TLVs here? */ | |
1018 | } | |
1019 | ||
1020 | ||
1021 | static void | |
1022 | babel_tx_hook(sock *sk) | |
1023 | { | |
1024 | struct babel_iface *ifa = sk->data; | |
1025 | ||
1026 | DBG("Babel: TX hook called (iface %s, src %I, dst %I)\n", | |
1027 | sk->iface->name, sk->saddr, sk->daddr); | |
1028 | ||
1029 | babel_send_queue(ifa); | |
1030 | } | |
1031 | ||
1032 | ||
1033 | static int | |
3e236955 | 1034 | babel_rx_hook(sock *sk, uint len) |
937e75d8 OZ |
1035 | { |
1036 | struct babel_iface *ifa = sk->data; | |
1037 | struct babel_proto *p = ifa->proto; | |
1038 | const char *err_dsc = NULL; | |
1039 | uint err_val = 0; | |
1040 | ||
1041 | if (sk->lifindex != ifa->iface->index) | |
1042 | return 1; | |
1043 | ||
1044 | DBG("Babel: RX hook called (iface %s, src %I, dst %I)\n", | |
1045 | sk->iface->name, sk->faddr, sk->laddr); | |
1046 | ||
1047 | /* Silently ignore my own packets */ | |
1048 | if (ipa_equal(ifa->iface->addr->ip, sk->faddr)) | |
1049 | return 1; | |
1050 | ||
1051 | if (!ipa_is_link_local(sk->faddr)) | |
1052 | DROP1("wrong src address"); | |
1053 | ||
1054 | if (sk->fport != ifa->cf->port) | |
1055 | DROP("wrong src port", sk->fport); | |
1056 | ||
1057 | if (len < sizeof(struct babel_pkt_header)) | |
1058 | DROP("too short", len); | |
1059 | ||
1060 | if (sk->flags & SKF_TRUNCATED) | |
1061 | DROP("truncated", len); | |
1062 | ||
1063 | babel_process_packet((struct babel_pkt_header *) sk->rbuf, len, sk->faddr, ifa); | |
1064 | return 1; | |
1065 | ||
1066 | drop: | |
1067 | LOG_PKT("Bad packet from %I via %s - %s (%u)", | |
1068 | sk->faddr, sk->iface->name, err_dsc, err_val); | |
1069 | return 1; | |
1070 | } | |
1071 | ||
1072 | int | |
1073 | babel_open_socket(struct babel_iface *ifa) | |
1074 | { | |
1075 | struct babel_proto *p = ifa->proto; | |
1076 | ||
1077 | sock *sk; | |
1078 | sk = sk_new(ifa->pool); | |
1079 | sk->type = SK_UDP; | |
1080 | sk->sport = ifa->cf->port; | |
1081 | sk->dport = ifa->cf->port; | |
1082 | sk->iface = ifa->iface; | |
943478b0 | 1083 | sk->vrf = p->p.vrf; |
937e75d8 OZ |
1084 | |
1085 | sk->rx_hook = babel_rx_hook; | |
1086 | sk->tx_hook = babel_tx_hook; | |
1087 | sk->err_hook = babel_err_hook; | |
1088 | sk->data = ifa; | |
1089 | ||
1090 | sk->tos = ifa->cf->tx_tos; | |
1091 | sk->priority = ifa->cf->tx_priority; | |
1092 | sk->ttl = 1; | |
1093 | sk->flags = SKF_LADDR_RX; | |
1094 | ||
1095 | if (sk_open(sk) < 0) | |
1096 | goto err; | |
1097 | ||
1098 | if (sk_setup_multicast(sk) < 0) | |
1099 | goto err; | |
1100 | ||
1101 | if (sk_join_group(sk, IP6_BABEL_ROUTERS) < 0) | |
1102 | goto err; | |
1103 | ||
1104 | ifa->sk = sk; | |
1105 | return 1; | |
1106 | ||
1107 | err: | |
1108 | sk_log_error(sk, p->p.name); | |
1109 | rfree(sk); | |
1110 | return 0; | |
1111 | } |