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 flags;
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: /* Hello flags */
108: #define BABEL_HF_UNICAST 0x8000
109:
110: /* Update flags */
111: #define BABEL_UF_DEF_PREFIX 0x80
112: #define BABEL_UF_ROUTER_ID 0x40
113:
114:
115: struct babel_parse_state {
116: struct babel_proto *proto;
117: struct babel_iface *ifa;
118: ip_addr saddr;
119: ip_addr next_hop;
120: u64 router_id; /* Router ID used in subsequent updates */
121: u8 def_ip6_prefix[16]; /* Implicit IPv6 prefix in network order */
122: u8 def_ip4_prefix[4]; /* Implicit IPv4 prefix in network order */
123: u8 router_id_seen; /* router_id field is valid */
124: u8 def_ip6_prefix_seen; /* def_ip6_prefix is valid */
125: u8 def_ip4_prefix_seen; /* def_ip4_prefix is valid */
126: };
127:
128: enum parse_result {
129: PARSE_SUCCESS,
130: PARSE_ERROR,
131: PARSE_IGNORE,
132: };
133:
134: struct babel_write_state {
135: u64 router_id;
136: u8 router_id_seen;
137: // ip_addr next_hop;
138: };
139:
140:
141: #define DROP(DSC,VAL) do { err_dsc = DSC; err_val = VAL; goto drop; } while(0)
142: #define DROP1(DSC) do { err_dsc = DSC; goto drop; } while(0)
143: #define LOG_PKT(msg, args...) \
144: log_rl(&p->log_pkt_tbf, L_REMOTE "%s: " msg, p->p.name, args)
145:
146: #define FIRST_TLV(p) ((struct babel_tlv *) (((struct babel_pkt_header *) p) + 1))
147: #define NEXT_TLV(t) ((struct babel_tlv *) (((byte *) t) + TLV_LENGTH(t)))
148: #define TLV_LENGTH(t) (t->type == BABEL_TLV_PAD1 ? 1 : t->length + sizeof(struct babel_tlv))
149: #define TLV_OPT_LENGTH(t) (t->length + sizeof(struct babel_tlv) - sizeof(*t))
150: #define TLV_HDR(tlv,t,l) ({ tlv->type = t; tlv->length = l - sizeof(struct babel_tlv); })
151: #define TLV_HDR0(tlv,t) TLV_HDR(tlv, t, tlv_data[t].min_length)
152:
153: static inline u16
154: get_time16(const void *p)
155: {
156: u16 v = get_u16(p) / BABEL_TIME_UNITS;
157: return MAX(1, v);
158: }
159:
160: static inline void
161: put_time16(void *p, u16 v)
162: {
163: put_u16(p, v * BABEL_TIME_UNITS);
164: }
165:
166: static inline ip6_addr
167: get_ip6_px(const void *p, uint plen)
168: {
169: ip6_addr addr = IPA_NONE;
170: memcpy(&addr, p, BYTES(plen));
171: return ip6_ntoh(addr);
172: }
173:
174: static inline void
175: put_ip6_px(void *p, ip6_addr addr, uint plen)
176: {
177: addr = ip6_hton(addr);
178: memcpy(p, &addr, BYTES(plen));
179: }
180:
181: static inline ip6_addr
182: get_ip6_ll(const void *p)
183: {
184: return ip6_build(0xfe800000, 0, get_u32(p+0), get_u32(p+4));
185: }
186:
187: static inline void
188: put_ip6_ll(void *p, ip6_addr addr)
189: {
190: put_u32(p+0, _I2(addr));
191: put_u32(p+4, _I3(addr));
192: }
193:
194:
195: /*
196: * TLV read/write functions
197: */
198:
199: static int babel_read_ack_req(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
200: static int babel_read_hello(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
201: static int babel_read_ihu(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
202: static int babel_read_router_id(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
203: static int babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
204: static int babel_read_update(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
205: static int babel_read_route_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
206: static int babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_parse_state *state);
207:
208: static uint babel_write_ack(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
209: static uint babel_write_hello(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
210: static uint babel_write_ihu(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
211: static uint babel_write_update(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
212: static uint babel_write_route_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
213: static uint babel_write_seqno_request(struct babel_tlv *hdr, union babel_msg *msg, struct babel_write_state *state, uint max_len);
214:
215: struct babel_tlv_data {
216: u8 min_length;
217: int (*read_tlv)(struct babel_tlv *hdr, union babel_msg *m, struct babel_parse_state *state);
218: uint (*write_tlv)(struct babel_tlv *hdr, union babel_msg *m, struct babel_write_state *state, uint max_len);
219: void (*handle_tlv)(union babel_msg *m, struct babel_iface *ifa);
220: };
221:
222: static const struct babel_tlv_data tlv_data[BABEL_TLV_MAX] = {
223: [BABEL_TLV_ACK_REQ] = {
224: sizeof(struct babel_tlv_ack_req),
225: babel_read_ack_req,
226: NULL,
227: babel_handle_ack_req
228: },
229: [BABEL_TLV_ACK] = {
230: sizeof(struct babel_tlv_ack),
231: NULL,
232: babel_write_ack,
233: NULL
234: },
235: [BABEL_TLV_HELLO] = {
236: sizeof(struct babel_tlv_hello),
237: babel_read_hello,
238: babel_write_hello,
239: babel_handle_hello
240: },
241: [BABEL_TLV_IHU] = {
242: sizeof(struct babel_tlv_ihu),
243: babel_read_ihu,
244: babel_write_ihu,
245: babel_handle_ihu
246: },
247: [BABEL_TLV_ROUTER_ID] = {
248: sizeof(struct babel_tlv_router_id),
249: babel_read_router_id,
250: NULL,
251: NULL
252: },
253: [BABEL_TLV_NEXT_HOP] = {
254: sizeof(struct babel_tlv_next_hop),
255: babel_read_next_hop,
256: NULL,
257: NULL
258: },
259: [BABEL_TLV_UPDATE] = {
260: sizeof(struct babel_tlv_update),
261: babel_read_update,
262: babel_write_update,
263: babel_handle_update
264: },
265: [BABEL_TLV_ROUTE_REQUEST] = {
266: sizeof(struct babel_tlv_route_request),
267: babel_read_route_request,
268: babel_write_route_request,
269: babel_handle_route_request
270: },
271: [BABEL_TLV_SEQNO_REQUEST] = {
272: sizeof(struct babel_tlv_seqno_request),
273: babel_read_seqno_request,
274: babel_write_seqno_request,
275: babel_handle_seqno_request
276: },
277: };
278:
279: static int
280: babel_read_ack_req(struct babel_tlv *hdr, union babel_msg *m,
281: struct babel_parse_state *state)
282: {
283: struct babel_tlv_ack_req *tlv = (void *) hdr;
284: struct babel_msg_ack_req *msg = &m->ack_req;
285:
286: msg->type = BABEL_TLV_ACK_REQ;
287: msg->nonce = get_u16(&tlv->nonce);
288: msg->interval = get_time16(&tlv->interval);
289: msg->sender = state->saddr;
290:
291: if (!msg->interval)
292: return PARSE_ERROR;
293:
294: return PARSE_SUCCESS;
295: }
296:
297: static uint
298: babel_write_ack(struct babel_tlv *hdr, union babel_msg *m,
299: struct babel_write_state *state UNUSED, uint max_len UNUSED)
300: {
301: struct babel_tlv_ack *tlv = (void *) hdr;
302: struct babel_msg_ack *msg = &m->ack;
303:
304: TLV_HDR0(tlv, BABEL_TLV_ACK);
305: put_u16(&tlv->nonce, msg->nonce);
306:
307: return sizeof(struct babel_tlv_ack);
308: }
309:
310: static int
311: babel_read_hello(struct babel_tlv *hdr, union babel_msg *m,
312: struct babel_parse_state *state)
313: {
314: struct babel_tlv_hello *tlv = (void *) hdr;
315: struct babel_msg_hello *msg = &m->hello;
316:
317: /* We currently don't support unicast Hello */
318: u16 flags = get_u16(&tlv->flags);
319: if (flags & BABEL_HF_UNICAST)
320: return PARSE_IGNORE;
321:
322: msg->type = BABEL_TLV_HELLO;
323: msg->seqno = get_u16(&tlv->seqno);
324: msg->interval = get_time16(&tlv->interval);
325: msg->sender = state->saddr;
326:
327: return PARSE_SUCCESS;
328: }
329:
330: static uint
331: babel_write_hello(struct babel_tlv *hdr, union babel_msg *m,
332: struct babel_write_state *state UNUSED, uint max_len UNUSED)
333: {
334: struct babel_tlv_hello *tlv = (void *) hdr;
335: struct babel_msg_hello *msg = &m->hello;
336:
337: TLV_HDR0(tlv, BABEL_TLV_HELLO);
338: put_u16(&tlv->seqno, msg->seqno);
339: put_time16(&tlv->interval, msg->interval);
340:
341: return sizeof(struct babel_tlv_hello);
342: }
343:
344: static int
345: babel_read_ihu(struct babel_tlv *hdr, union babel_msg *m,
346: struct babel_parse_state *state)
347: {
348: struct babel_tlv_ihu *tlv = (void *) hdr;
349: struct babel_msg_ihu *msg = &m->ihu;
350:
351: msg->type = BABEL_TLV_IHU;
352: msg->ae = tlv->ae;
353: msg->rxcost = get_u16(&tlv->rxcost);
354: msg->interval = get_time16(&tlv->interval);
355: msg->addr = IPA_NONE;
356: msg->sender = state->saddr;
357:
358: if (msg->ae >= BABEL_AE_MAX)
359: return PARSE_IGNORE;
360:
361: // We handle link-local IPs. In every other case, the addr field will be 0 but
362: // validation will succeed. The handler takes care of these cases.
363: if (msg->ae == BABEL_AE_IP6_LL)
364: {
365: if (TLV_OPT_LENGTH(tlv) < 8)
366: return PARSE_ERROR;
367:
368: msg->addr = ipa_from_ip6(get_ip6_ll(&tlv->addr));
369: }
370:
371: return PARSE_SUCCESS;
372: }
373:
374: static uint
375: babel_write_ihu(struct babel_tlv *hdr, union babel_msg *m,
376: struct babel_write_state *state UNUSED, uint max_len)
377: {
378: struct babel_tlv_ihu *tlv = (void *) hdr;
379: struct babel_msg_ihu *msg = &m->ihu;
380:
381: if (ipa_is_link_local(msg->addr) && max_len < sizeof(struct babel_tlv_ihu) + 8)
382: return 0;
383:
384: TLV_HDR0(tlv, BABEL_TLV_IHU);
385: put_u16(&tlv->rxcost, msg->rxcost);
386: put_time16(&tlv->interval, msg->interval);
387:
388: if (!ipa_is_link_local(msg->addr))
389: {
390: tlv->ae = BABEL_AE_WILDCARD;
391: return sizeof(struct babel_tlv_ihu);
392: }
393: put_ip6_ll(&tlv->addr, msg->addr);
394: tlv->ae = BABEL_AE_IP6_LL;
395: hdr->length += 8;
396: return sizeof(struct babel_tlv_ihu) + 8;
397: }
398:
399: static int
400: babel_read_router_id(struct babel_tlv *hdr, union babel_msg *m UNUSED,
401: struct babel_parse_state *state)
402: {
403: struct babel_tlv_router_id *tlv = (void *) hdr;
404:
405: state->router_id = get_u64(&tlv->router_id);
406: state->router_id_seen = 1;
407:
408: return PARSE_IGNORE;
409: }
410:
411: /* This is called directly from babel_write_update() */
412: static uint
413: babel_write_router_id(struct babel_tlv *hdr, u64 router_id,
414: struct babel_write_state *state, uint max_len UNUSED)
415: {
416: struct babel_tlv_router_id *tlv = (void *) hdr;
417:
418: /* We still assume that first min_length bytes are available and zeroed */
419:
420: TLV_HDR0(tlv, BABEL_TLV_ROUTER_ID);
421: put_u64(&tlv->router_id, router_id);
422:
423: state->router_id = router_id;
424: state->router_id_seen = 1;
425:
426: return sizeof(struct babel_tlv_router_id);
427: }
428:
429: static int
430: babel_read_next_hop(struct babel_tlv *hdr, union babel_msg *m UNUSED,
431: struct babel_parse_state *state)
432: {
433: struct babel_tlv_next_hop *tlv = (void *) hdr;
434:
435: switch (tlv->ae)
436: {
437: case BABEL_AE_WILDCARD:
438: return PARSE_ERROR;
439:
440: case BABEL_AE_IP4:
441: /* TODO */
442: return PARSE_IGNORE;
443:
444: case BABEL_AE_IP6:
445: if (TLV_OPT_LENGTH(tlv) < sizeof(ip6_addr))
446: return PARSE_ERROR;
447:
448: state->next_hop = ipa_from_ip6(get_ip6(&tlv->addr));
449: return PARSE_IGNORE;
450:
451: case BABEL_AE_IP6_LL:
452: if (TLV_OPT_LENGTH(tlv) < 8)
453: return PARSE_ERROR;
454:
455: state->next_hop = ipa_from_ip6(get_ip6_ll(&tlv->addr));
456: return PARSE_IGNORE;
457:
458: default:
459: return PARSE_IGNORE;
460: }
461:
462: return PARSE_IGNORE;
463: }
464:
465: static int
466: babel_read_update(struct babel_tlv *hdr, union babel_msg *m,
467: struct babel_parse_state *state)
468: {
469: struct babel_tlv_update *tlv = (void *) hdr;
470: struct babel_msg_update *msg = &m->update;
471:
472: msg->type = BABEL_TLV_UPDATE;
473: msg->interval = get_time16(&tlv->interval);
474: msg->seqno = get_u16(&tlv->seqno);
475: msg->metric = get_u16(&tlv->metric);
476:
477: /* Length of received prefix data without omitted part */
478: int len = BYTES(tlv->plen) - (int) tlv->omitted;
479: u8 buf[16] = {};
480:
481: if ((len < 0) || ((uint) len > TLV_OPT_LENGTH(tlv)))
482: return PARSE_ERROR;
483:
484: switch (tlv->ae)
485: {
486: case BABEL_AE_WILDCARD:
487: if (tlv->plen > 0)
488: return PARSE_ERROR;
489:
490: msg->wildcard = 1;
491: break;
492:
493: case BABEL_AE_IP4:
494: /* TODO */
495: return PARSE_IGNORE;
496:
497: case BABEL_AE_IP6:
498: if (tlv->plen > MAX_PREFIX_LENGTH)
499: return PARSE_ERROR;
500:
501: /* Cannot omit data if there is no saved prefix */
502: if (tlv->omitted && !state->def_ip6_prefix_seen)
503: return PARSE_ERROR;
504:
505: /* Merge saved prefix and received prefix parts */
506: memcpy(buf, state->def_ip6_prefix, tlv->omitted);
507: memcpy(buf + tlv->omitted, tlv->addr, len);
508:
509: msg->plen = tlv->plen;
510: msg->prefix = ipa_from_ip6(get_ip6(buf));
511:
512: if (tlv->flags & BABEL_UF_DEF_PREFIX)
513: {
514: put_ip6(state->def_ip6_prefix, msg->prefix);
515: state->def_ip6_prefix_seen = 1;
516: }
517:
518: if (tlv->flags & BABEL_UF_ROUTER_ID)
519: {
520: state->router_id = ((u64) _I2(msg->prefix)) << 32 | _I3(msg->prefix);
521: state->router_id_seen = 1;
522: }
523: break;
524:
525: case BABEL_AE_IP6_LL:
526: /* ??? */
527: return PARSE_IGNORE;
528:
529: default:
530: return PARSE_IGNORE;
531: }
532:
533: /* Update must have Router ID, unless it is retraction */
534: if (!state->router_id_seen && (msg->metric != BABEL_INFINITY))
535: {
536: DBG("Babel: No router ID seen before update\n");
537: return PARSE_ERROR;
538: }
539:
540: msg->router_id = state->router_id;
541: msg->next_hop = state->next_hop;
542: msg->sender = state->saddr;
543:
544: return PARSE_SUCCESS;
545: }
546:
547: static uint
548: babel_write_update(struct babel_tlv *hdr, union babel_msg *m,
549: struct babel_write_state *state, uint max_len)
550: {
551: struct babel_tlv_update *tlv = (void *) hdr;
552: struct babel_msg_update *msg = &m->update;
553: uint len0 = 0;
554:
555: /*
556: * When needed, we write Router-ID TLV before Update TLV and return size of
557: * both of them. There is enough space for the Router-ID TLV, because
558: * sizeof(struct babel_tlv_router_id) == sizeof(struct babel_tlv_update).
559: *
560: * Router ID is not used for retractions, so do not us it in such case.
561: */
562: if ((msg->metric < BABEL_INFINITY) &&
563: (!state->router_id_seen || (msg->router_id != state->router_id)))
564: {
565: len0 = babel_write_router_id(hdr, msg->router_id, state, max_len);
566: tlv = (struct babel_tlv_update *) NEXT_TLV(tlv);
567: }
568:
569: uint len = sizeof(struct babel_tlv_update) + BYTES(msg->plen);
570:
571: if (len0 + len > max_len)
572: return 0;
573:
574: memset(tlv, 0, sizeof(struct babel_tlv_update));
575: TLV_HDR(tlv, BABEL_TLV_UPDATE, len);
576:
577: if (msg->wildcard)
578: {
579: tlv->ae = BABEL_AE_WILDCARD;
580: tlv->plen = 0;
581: }
582: else
583: {
584: tlv->ae = BABEL_AE_IP6;
585: tlv->plen = msg->plen;
586: put_ip6_px(tlv->addr, msg->prefix, msg->plen);
587: }
588:
589: put_time16(&tlv->interval, msg->interval);
590: put_u16(&tlv->seqno, msg->seqno);
591: put_u16(&tlv->metric, msg->metric);
592:
593: return len0 + len;
594: }
595:
596: static int
597: babel_read_route_request(struct babel_tlv *hdr, union babel_msg *m,
598: struct babel_parse_state *state UNUSED)
599: {
600: struct babel_tlv_route_request *tlv = (void *) hdr;
601: struct babel_msg_route_request *msg = &m->route_request;
602:
603: msg->type = BABEL_TLV_ROUTE_REQUEST;
604:
605: switch (tlv->ae)
606: {
607: case BABEL_AE_WILDCARD:
608: /* Wildcard requests must have plen 0 */
609: if (tlv->plen > 0)
610: return PARSE_ERROR;
611:
612: msg->full = 1;
613: return PARSE_SUCCESS;
614:
615: case BABEL_AE_IP4:
616: /* TODO */
617: return PARSE_IGNORE;
618:
619: case BABEL_AE_IP6:
620: if (tlv->plen > MAX_PREFIX_LENGTH)
621: return PARSE_ERROR;
622:
623: if (TLV_OPT_LENGTH(tlv) < BYTES(tlv->plen))
624: return PARSE_ERROR;
625:
626: msg->plen = tlv->plen;
627: msg->prefix = get_ip6_px(tlv->addr, tlv->plen);
628: return PARSE_SUCCESS;
629:
630: case BABEL_AE_IP6_LL:
631: return PARSE_ERROR;
632:
633: default:
634: return PARSE_IGNORE;
635: }
636:
637: return PARSE_IGNORE;
638: }
639:
640: static uint
641: babel_write_route_request(struct babel_tlv *hdr, union babel_msg *m,
642: struct babel_write_state *state UNUSED, uint max_len)
643: {
644: struct babel_tlv_route_request *tlv = (void *) hdr;
645: struct babel_msg_route_request *msg = &m->route_request;
646:
647: uint len = sizeof(struct babel_tlv_route_request) + BYTES(msg->plen);
648:
649: if (len > max_len)
650: return 0;
651:
652: TLV_HDR(tlv, BABEL_TLV_ROUTE_REQUEST, len);
653:
654: if (msg->full)
655: {
656: tlv->ae = BABEL_AE_WILDCARD;
657: tlv->plen = 0;
658: }
659: else
660: {
661: tlv->ae = BABEL_AE_IP6;
662: tlv->plen = msg->plen;
663: put_ip6_px(tlv->addr, msg->prefix, msg->plen);
664: }
665:
666: return len;
667: }
668:
669: static int
670: babel_read_seqno_request(struct babel_tlv *hdr, union babel_msg *m,
671: struct babel_parse_state *state)
672: {
673: struct babel_tlv_seqno_request *tlv = (void *) hdr;
674: struct babel_msg_seqno_request *msg = &m->seqno_request;
675:
676: msg->type = BABEL_TLV_SEQNO_REQUEST;
677: msg->seqno = get_u16(&tlv->seqno);
678: msg->hop_count = tlv->hop_count;
679: msg->router_id = get_u64(&tlv->router_id);
680: msg->sender = state->saddr;
681:
682: if (tlv->hop_count == 0)
683: return PARSE_ERROR;
684:
685: switch (tlv->ae)
686: {
687: case BABEL_AE_WILDCARD:
688: return PARSE_ERROR;
689:
690: case BABEL_AE_IP4:
691: /* TODO */
692: return PARSE_IGNORE;
693:
694: case BABEL_AE_IP6:
695: if (tlv->plen > MAX_PREFIX_LENGTH)
696: return PARSE_ERROR;
697:
698: if (TLV_OPT_LENGTH(tlv) < BYTES(tlv->plen))
699: return PARSE_ERROR;
700:
701: msg->plen = tlv->plen;
702: msg->prefix = get_ip6_px(tlv->addr, tlv->plen);
703: return PARSE_SUCCESS;
704:
705: case BABEL_AE_IP6_LL:
706: return PARSE_ERROR;
707:
708: default:
709: return PARSE_IGNORE;
710: }
711:
712: return PARSE_IGNORE;
713: }
714:
715: static uint
716: babel_write_seqno_request(struct babel_tlv *hdr, union babel_msg *m,
717: struct babel_write_state *state UNUSED, uint max_len)
718: {
719: struct babel_tlv_seqno_request *tlv = (void *) hdr;
720: struct babel_msg_seqno_request *msg = &m->seqno_request;
721:
722: uint len = sizeof(struct babel_tlv_seqno_request) + BYTES(msg->plen);
723:
724: if (len > max_len)
725: return 0;
726:
727: TLV_HDR(tlv, BABEL_TLV_SEQNO_REQUEST, len);
728: tlv->ae = BABEL_AE_IP6;
729: tlv->plen = msg->plen;
730: put_u16(&tlv->seqno, msg->seqno);
731: tlv->hop_count = msg->hop_count;
732: put_u64(&tlv->router_id, msg->router_id);
733: put_ip6_px(tlv->addr, msg->prefix, msg->plen);
734:
735: return len;
736: }
737:
738: static inline int
739: babel_read_tlv(struct babel_tlv *hdr,
740: union babel_msg *msg,
741: struct babel_parse_state *state)
742: {
743: if ((hdr->type <= BABEL_TLV_PADN) ||
744: (hdr->type >= BABEL_TLV_MAX) ||
745: !tlv_data[hdr->type].read_tlv)
746: return PARSE_IGNORE;
747:
748: if (TLV_LENGTH(hdr) < tlv_data[hdr->type].min_length)
749: return PARSE_ERROR;
750:
751: memset(msg, 0, sizeof(*msg));
752: return tlv_data[hdr->type].read_tlv(hdr, msg, state);
753: }
754:
755: static uint
756: babel_write_tlv(struct babel_tlv *hdr,
757: union babel_msg *msg,
758: struct babel_write_state *state,
759: uint max_len)
760: {
761: if ((msg->type <= BABEL_TLV_PADN) ||
762: (msg->type >= BABEL_TLV_MAX) ||
763: !tlv_data[msg->type].write_tlv)
764: return 0;
765:
766: if (tlv_data[msg->type].min_length > max_len)
767: return 0;
768:
769: memset(hdr, 0, tlv_data[msg->type].min_length);
770: return tlv_data[msg->type].write_tlv(hdr, msg, state, max_len);
771: }
772:
773:
774: /*
775: * Packet RX/TX functions
776: */
777:
778: static int
779: babel_send_to(struct babel_iface *ifa, ip_addr dest)
780: {
781: sock *sk = ifa->sk;
782: struct babel_pkt_header *hdr = (void *) sk->tbuf;
783: int len = get_u16(&hdr->length) + sizeof(struct babel_pkt_header);
784:
785: DBG("Babel: Sending %d bytes to %I\n", len, dest);
786: return sk_send_to(sk, len, dest, 0);
787: }
788:
789: /**
790: * babel_write_queue - Write a TLV queue to a transmission buffer
791: * @ifa: Interface holding the transmission buffer
792: * @queue: TLV queue to write (containing internal-format TLVs)
793: *
794: * This function writes a packet to the interface transmission buffer with as
795: * many TLVs from the &queue as will fit in the buffer. It returns the number of
796: * bytes written (NOT counting the packet header). The function is called by
797: * babel_send_queue() and babel_send_unicast() to construct packets for
798: * transmission, and uses per-TLV helper functions to convert the
799: * internal-format TLVs to their wire representations.
800: *
801: * The TLVs in the queue are freed after they are written to the buffer.
802: */
803: static uint
804: babel_write_queue(struct babel_iface *ifa, list *queue)
805: {
806: struct babel_proto *p = ifa->proto;
807: struct babel_write_state state = {};
808:
809: if (EMPTY_LIST(*queue))
810: return 0;
811:
812: byte *pos = ifa->sk->tbuf;
813: byte *end = pos + ifa->tx_length;
814:
815: struct babel_pkt_header *pkt = (void *) pos;
816: pkt->magic = BABEL_MAGIC;
817: pkt->version = BABEL_VERSION;
818: pkt->length = 0;
819: pos += sizeof(struct babel_pkt_header);
820:
821: struct babel_msg_node *msg;
822: WALK_LIST_FIRST(msg, *queue)
823: {
824: if (pos >= end)
825: break;
826:
827: int len = babel_write_tlv((struct babel_tlv *) pos, &msg->msg, &state, end - pos);
828:
829: if (!len)
830: break;
831:
832: pos += len;
833: rem_node(NODE msg);
834: sl_free(p->msg_slab, msg);
835: }
836:
837: uint plen = pos - (byte *) pkt;
838: put_u16(&pkt->length, plen - sizeof(struct babel_pkt_header));
839:
840: return plen;
841: }
842:
843: void
844: babel_send_queue(void *arg)
845: {
846: struct babel_iface *ifa = arg;
847: while ((babel_write_queue(ifa, &ifa->msg_queue) > 0) &&
848: (babel_send_to(ifa, IP6_BABEL_ROUTERS) > 0));
849: }
850:
851: static inline void
852: babel_kick_queue(struct babel_iface *ifa)
853: {
854: /*
855: * Only schedule send event if there is not already data in the socket buffer.
856: * Otherwise we may overwrite the data already in the buffer.
857: */
858:
859: if ((ifa->sk->tpos == ifa->sk->tbuf) && !ev_active(ifa->send_event))
860: ev_schedule(ifa->send_event);
861: }
862:
863: /**
864: * babel_send_unicast - send a single TLV via unicast to a destination
865: * @msg: TLV to send
866: * @ifa: Interface to send via
867: * @dest: Destination of the TLV
868: *
869: * This function is used to send a single TLV via unicast to a designated
870: * receiver. This is used for replying to certain incoming requests, and for
871: * sending unicast requests to refresh routes before they expire.
872: */
873: void
874: babel_send_unicast(union babel_msg *msg, struct babel_iface *ifa, ip_addr dest)
875: {
876: struct babel_proto *p = ifa->proto;
877: struct babel_msg_node *msgn = sl_alloc(p->msg_slab);
878: list queue;
879:
880: msgn->msg = *msg;
881: init_list(&queue);
882: add_tail(&queue, NODE msgn);
883: babel_write_queue(ifa, &queue);
884: babel_send_to(ifa, dest);
885:
886: /* We could overwrite waiting packet here, we may have to kick TX queue */
887: if (!EMPTY_LIST(ifa->msg_queue))
888: babel_kick_queue(ifa);
889: }
890:
891: /**
892: * babel_enqueue - enqueue a TLV for transmission on an interface
893: * @msg: TLV to enqueue (in internal TLV format)
894: * @ifa: Interface to enqueue to
895: *
896: * This function is called to enqueue a TLV for subsequent transmission on an
897: * interface. The transmission event is triggered whenever a TLV is enqueued;
898: * this ensures that TLVs will be transmitted in a timely manner, but that TLVs
899: * which are enqueued in rapid succession can be transmitted together in one
900: * packet.
901: */
902: void
903: babel_enqueue(union babel_msg *msg, struct babel_iface *ifa)
904: {
905: struct babel_proto *p = ifa->proto;
906: struct babel_msg_node *msgn = sl_alloc(p->msg_slab);
907: msgn->msg = *msg;
908: add_tail(&ifa->msg_queue, NODE msgn);
909: babel_kick_queue(ifa);
910: }
911:
912: /**
913: * babel_process_packet - process incoming data packet
914: * @pkt: Pointer to the packet data
915: * @len: Length of received packet
916: * @saddr: Address of packet sender
917: * @ifa: Interface packet was received on.
918: *
919: * This function is the main processing hook of incoming Babel packets. It
920: * checks that the packet header is well-formed, then processes the TLVs
921: * contained in the packet. This is done in two passes: First all TLVs are
922: * parsed into the internal TLV format. If a TLV parser fails, processing of the
923: * rest of the packet is aborted.
924: *
925: * After the parsing step, the TLV handlers are called for each parsed TLV in
926: * order.
927: */
928: static void
929: babel_process_packet(struct babel_pkt_header *pkt, int len,
930: ip_addr saddr, struct babel_iface *ifa)
931: {
932: struct babel_proto *p = ifa->proto;
933: struct babel_tlv *tlv;
934: struct babel_msg_node *msg;
935: list msgs;
936: int res;
937:
938: int plen = sizeof(struct babel_pkt_header) + get_u16(&pkt->length);
939: byte *pos;
940: byte *end = (byte *)pkt + plen;
941:
942: struct babel_parse_state state = {
943: .proto = p,
944: .ifa = ifa,
945: .saddr = saddr,
946: .next_hop = saddr,
947: };
948:
949: if ((pkt->magic != BABEL_MAGIC) || (pkt->version != BABEL_VERSION))
950: {
951: TRACE(D_PACKETS, "Strange packet from %I via %s - magic %d version %d",
952: saddr, ifa->iface->name, pkt->magic, pkt->version);
953: return;
954: }
955:
956: if (plen > len)
957: {
958: LOG_PKT("Bad packet from %I via %s - %s (%u)",
959: saddr, ifa->iface->name, "length mismatch", plen);
960: return;
961: }
962:
963: TRACE(D_PACKETS, "Packet received from %I via %s",
964: saddr, ifa->iface->name);
965:
966: init_list(&msgs);
967:
968: /* First pass through the packet TLV by TLV, parsing each into internal data
969: structures. */
970: for (tlv = FIRST_TLV(pkt);
971: (byte *)tlv < end;
972: tlv = NEXT_TLV(tlv))
973: {
974: /* Ugly special case */
975: if (tlv->type == BABEL_TLV_PAD1)
976: continue;
977:
978: /* The end of the common TLV header */
979: pos = (byte *)tlv + sizeof(struct babel_tlv);
980: if ((pos > end) || (pos + tlv->length > end))
981: {
982: LOG_PKT("Bad TLV from %I via %s type %d pos %d - framing error",
983: saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt);
984: break;
985: }
986:
987: msg = sl_alloc(p->msg_slab);
988: res = babel_read_tlv(tlv, &msg->msg, &state);
989: if (res == PARSE_SUCCESS)
990: {
991: add_tail(&msgs, NODE msg);
992: }
993: else if (res == PARSE_IGNORE)
994: {
995: DBG("Babel: Ignoring TLV of type %d\n", tlv->type);
996: sl_free(p->msg_slab, msg);
997: }
998: else /* PARSE_ERROR */
999: {
1000: LOG_PKT("Bad TLV from %I via %s type %d pos %d - parse error",
1001: saddr, ifa->iface->name, tlv->type, (byte *)tlv - (byte *)pkt);
1002: sl_free(p->msg_slab, msg);
1003: break;
1004: }
1005: }
1006:
1007: /* Parsing done, handle all parsed TLVs */
1008: WALK_LIST_FIRST(msg, msgs)
1009: {
1010: if (tlv_data[msg->msg.type].handle_tlv)
1011: tlv_data[msg->msg.type].handle_tlv(&msg->msg, ifa);
1012: rem_node(NODE msg);
1013: sl_free(p->msg_slab, msg);
1014: }
1015: }
1016:
1017: static void
1018: babel_err_hook(sock *sk, int err)
1019: {
1020: struct babel_iface *ifa = sk->data;
1021: struct babel_proto *p = ifa->proto;
1022:
1023: log(L_ERR "%s: Socket error on %s: %M", p->p.name, ifa->iface->name, err);
1024: /* FIXME: Drop queued TLVs here? */
1025: }
1026:
1027:
1028: static void
1029: babel_tx_hook(sock *sk)
1030: {
1031: struct babel_iface *ifa = sk->data;
1032:
1033: DBG("Babel: TX hook called (iface %s, src %I, dst %I)\n",
1034: sk->iface->name, sk->saddr, sk->daddr);
1035:
1036: babel_send_queue(ifa);
1037: }
1038:
1039:
1040: static int
1041: babel_rx_hook(sock *sk, uint len)
1042: {
1043: struct babel_iface *ifa = sk->data;
1044: struct babel_proto *p = ifa->proto;
1045: const char *err_dsc = NULL;
1046: uint err_val = 0;
1047:
1048: if (sk->lifindex != ifa->iface->index)
1049: return 1;
1050:
1051: DBG("Babel: RX hook called (iface %s, src %I, dst %I)\n",
1052: sk->iface->name, sk->faddr, sk->laddr);
1053:
1054: /* Silently ignore my own packets */
1055: if (ipa_equal(ifa->iface->addr->ip, sk->faddr))
1056: return 1;
1057:
1058: if (!ipa_is_link_local(sk->faddr))
1059: DROP1("wrong src address");
1060:
1061: if (sk->fport != ifa->cf->port)
1062: DROP("wrong src port", sk->fport);
1063:
1064: if (len < sizeof(struct babel_pkt_header))
1065: DROP("too short", len);
1066:
1067: if (sk->flags & SKF_TRUNCATED)
1068: DROP("truncated", len);
1069:
1070: babel_process_packet((struct babel_pkt_header *) sk->rbuf, len, sk->faddr, ifa);
1071: return 1;
1072:
1073: drop:
1074: LOG_PKT("Bad packet from %I via %s - %s (%u)",
1075: sk->faddr, sk->iface->name, err_dsc, err_val);
1076: return 1;
1077: }
1078:
1079: int
1080: babel_open_socket(struct babel_iface *ifa)
1081: {
1082: struct babel_proto *p = ifa->proto;
1083:
1084: sock *sk;
1085: sk = sk_new(ifa->pool);
1086: sk->type = SK_UDP;
1087: sk->sport = ifa->cf->port;
1088: sk->dport = ifa->cf->port;
1089: sk->iface = ifa->iface;
1090: sk->saddr = ifa->addr;
1091: sk->vrf = p->p.vrf;
1092:
1093: sk->rx_hook = babel_rx_hook;
1094: sk->tx_hook = babel_tx_hook;
1095: sk->err_hook = babel_err_hook;
1096: sk->data = ifa;
1097:
1098: sk->tos = ifa->cf->tx_tos;
1099: sk->priority = ifa->cf->tx_priority;
1100: sk->ttl = 1;
1101: sk->flags = SKF_LADDR_RX;
1102:
1103: if (sk_open(sk) < 0)
1104: goto err;
1105:
1106: if (sk_setup_multicast(sk) < 0)
1107: goto err;
1108:
1109: if (sk_join_group(sk, IP6_BABEL_ROUTERS) < 0)
1110: goto err;
1111:
1112: ifa->sk = sk;
1113: return 1;
1114:
1115: err:
1116: sk_log_error(sk, p->p.name);
1117: rfree(sk);
1118: return 0;
1119: }
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