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avoid endless loop in processipcp, processipv6cp
[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.95 2006/02/17 14:35:54 bodea Exp $";
4
5 #include <stdio.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include <stdlib.h>
10 #include "l2tpns.h"
11 #include "constants.h"
12 #include "plugin.h"
13 #include "util.h"
14 #include "tbf.h"
15 #include "cluster.h"
16
17 extern tunnelt *tunnel;
18 extern sessiont *session;
19 extern radiust *radius;
20 extern int tunfd;
21 extern char hostname[];
22 extern uint32_t eth_tx;
23 extern time_t time_now;
24 extern configt *config;
25
26 static int add_lcp_auth(uint8_t *b, int size, int authtype);
27
28 // Process PAP messages
29 void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
30 {
31 char user[MAXUSER];
32 char pass[MAXPASS];
33 uint16_t hl;
34 uint16_t r;
35
36 CSTAT(processpap);
37
38 LOG_HEX(5, "PAP", p, l);
39 if (l < 4)
40 {
41 LOG(1, s, t, "Short PAP %u bytes\n", l);
42 STAT(tunnel_rx_errors);
43 sessionshutdown(s, "Short PAP packet.", 3, 0);
44 return;
45 }
46
47 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
48 {
49 LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
50 STAT(tunnel_rx_errors);
51 sessionshutdown(s, "PAP length mismatch.", 3, 0);
52 return;
53 }
54 l = hl;
55
56 if (*p != 1)
57 {
58 LOG(1, s, t, "Unexpected PAP code %d\n", *p);
59 STAT(tunnel_rx_errors);
60 sessionshutdown(s, "Unexpected PAP code.", 3, 0);
61 return;
62 }
63
64 if (session[s].ppp.phase != Authenticate)
65 {
66 LOG(2, s, t, "PAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
67 return;
68 }
69
70 {
71 uint8_t *b = p;
72 b += 4;
73 user[0] = pass[0] = 0;
74 if (*b && *b < sizeof(user))
75 {
76 memcpy(user, b + 1, *b);
77 user[*b] = 0;
78 b += 1 + *b;
79 if (*b && *b < sizeof(pass))
80 {
81 memcpy(pass, b + 1, *b);
82 pass[*b] = 0;
83 }
84 }
85 LOG(3, s, t, "PAP login %s/%s\n", user, pass);
86 }
87
88 if (session[s].ip || !(r = radiusnew(s)))
89 {
90 // respond now, either no RADIUS available or already authenticated
91 uint8_t b[MAXETHER];
92 uint8_t id = p[1];
93 uint8_t *p = makeppp(b, sizeof(b), 0, 0, s, t, PPPPAP);
94 if (!p) return;
95
96 if (session[s].ip)
97 *p = 2; // ACK
98 else
99 *p = 3; // cant authorise
100 p[1] = id;
101 *(uint16_t *) (p + 2) = htons(5); // length
102 p[4] = 0; // no message
103 tunnelsend(b, 5 + (p - b), t); // send it
104
105 if (session[s].ip)
106 {
107 LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
108 fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
109 }
110 else
111 {
112 LOG(1, s, t, "No RADIUS session available to authenticate session...\n");
113 sessionshutdown(s, "No free RADIUS sessions.", 4, 0);
114 }
115 }
116 else
117 {
118 // Run PRE_AUTH plugins
119 struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
120 run_plugins(PLUGIN_PRE_AUTH, &packet);
121 if (!packet.continue_auth)
122 {
123 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
124 if (packet.username) free(packet.username);
125 if (packet.password) free(packet.password);
126 return;
127 }
128
129 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
130 strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
131
132 free(packet.username);
133 free(packet.password);
134
135 radius[r].id = p[1];
136 LOG(3, s, t, "Sending login for %s/%s to RADIUS\n", user, pass);
137 radiussend(r, RADIUSAUTH);
138 }
139 }
140
141 // Process CHAP messages
142 void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
143 {
144 uint16_t r;
145 uint16_t hl;
146
147 CSTAT(processchap);
148
149 LOG_HEX(5, "CHAP", p, l);
150
151 if (l < 4)
152 {
153 LOG(1, s, t, "Short CHAP %u bytes\n", l);
154 STAT(tunnel_rx_errors);
155 sessionshutdown(s, "Short CHAP packet.", 3, 0);
156 return;
157 }
158
159 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
160 {
161 LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
162 STAT(tunnel_rx_errors);
163 sessionshutdown(s, "CHAP length mismatch.", 3, 0);
164 return;
165 }
166 l = hl;
167
168 if (*p != 2)
169 {
170 LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
171 STAT(tunnel_rx_errors);
172 sessionshutdown(s, "CHAP length mismatch.", 3, 0);
173 return;
174 }
175
176 r = sess_local[s].radius;
177 if (!r)
178 {
179 LOG(3, s, t, "Unexpected CHAP message\n");
180 return;
181 }
182
183 if (session[s].ppp.phase != Authenticate)
184 {
185 LOG(2, s, t, "CHAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
186 return;
187 }
188
189 if (p[1] != radius[r].id)
190 {
191 LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
192 STAT(tunnel_rx_errors);
193 sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0);
194 return;
195 }
196
197 if (l < 5 || p[4] != 16)
198 {
199 LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
200 STAT(tunnel_rx_errors);
201 sessionshutdown(s, "Bad CHAP response length.", 3, 0);
202 return;
203 }
204
205 l -= 5;
206 p += 5;
207 if (l < 16 || l - 16 >= sizeof(session[s].user))
208 {
209 LOG(1, s, t, "CHAP user too long %d\n", l - 16);
210 STAT(tunnel_rx_errors);
211 sessionshutdown(s, "CHAP username too long.", 3, 0);
212 return;
213 }
214
215 // Run PRE_AUTH plugins
216 {
217 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
218
219 packet.password = calloc(17, 1);
220 memcpy(packet.password, p, 16);
221
222 p += 16;
223 l -= 16;
224
225 packet.username = calloc(l + 1, 1);
226 memcpy(packet.username, p, l);
227
228 run_plugins(PLUGIN_PRE_AUTH, &packet);
229 if (!packet.continue_auth)
230 {
231 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
232 if (packet.username) free(packet.username);
233 if (packet.password) free(packet.password);
234 return;
235 }
236
237 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
238 memcpy(radius[r].pass, packet.password, 16);
239
240 free(packet.username);
241 free(packet.password);
242 }
243
244 radius[r].chap = 1;
245 LOG(3, s, t, "CHAP login %s\n", session[s].user);
246 radiussend(r, RADIUSAUTH);
247 }
248
249 static void dumplcp(uint8_t *p, int l)
250 {
251 int x = l - 4;
252 uint8_t *o = (p + 4);
253
254 LOG_HEX(5, "PPP LCP Packet", p, l);
255 LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_code((int)*p), ntohs( ((uint16_t *) p)[1]) );
256 LOG(4, 0, 0, "Length: %d\n", l);
257 if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
258 return;
259
260 while (x > 2)
261 {
262 int type = o[0];
263 int length = o[1];
264 if (length < 2)
265 {
266 LOG(4, 0, 0, " Option length is %d...\n", length);
267 break;
268 }
269 if (type == 0)
270 {
271 LOG(4, 0, 0, " Option type is 0...\n");
272 x -= length;
273 o += length;
274 continue;
275 }
276 switch (type)
277 {
278 case 1: // Maximum-Receive-Unit
279 if (length == 4)
280 LOG(4, 0, 0, " %s %d\n", ppp_lcp_option(type), ntohs(*(uint16_t *)(o + 2)));
281 else
282 LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
283 break;
284 case 2: // Async-Control-Character-Map
285 if (length == 6)
286 {
287 uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
288 LOG(4, 0, 0, " %s %x\n", ppp_lcp_option(type), asyncmap);
289 }
290 else
291 LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
292 break;
293 case 3: // Authentication-Protocol
294 if (length == 4)
295 {
296 int proto = ntohs(*(uint16_t *)(o + 2));
297 LOG(4, 0, 0, " %s 0x%x (%s)\n", ppp_lcp_option(type), proto,
298 proto == PPPPAP ? "PAP" : "UNSUPPORTED");
299 }
300 else if (length == 5)
301 {
302 int proto = ntohs(*(uint16_t *)(o + 2));
303 int algo = *(o + 4);
304 LOG(4, 0, 0, " %s 0x%x 0x%x (%s)\n", ppp_lcp_option(type), proto, algo,
305 (proto == PPPCHAP && algo == 5) ? "CHAP MD5" : "UNSUPPORTED");
306 }
307 else
308 LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
309 break;
310 case 4: // Quality-Protocol
311 {
312 uint32_t qp = ntohl(*(uint32_t *)(o + 2));
313 LOG(4, 0, 0, " %s %x\n", ppp_lcp_option(type), qp);
314 }
315 break;
316 case 5: // Magic-Number
317 if (length == 6)
318 {
319 uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
320 LOG(4, 0, 0, " %s %x\n", ppp_lcp_option(type), magicno);
321 }
322 else
323 LOG(4, 0, 0, " %s odd length %d\n", ppp_lcp_option(type), length);
324 break;
325 case 7: // Protocol-Field-Compression
326 case 8: // Address-And-Control-Field-Compression
327 LOG(4, 0, 0, " %s\n", ppp_lcp_option(type));
328 break;
329 default:
330 LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type);
331 break;
332 }
333 x -= length;
334 o += length;
335 }
336 }
337
338 void lcp_open(sessionidt s, tunnelidt t)
339 {
340 // transition to Authentication or Network phase:
341 session[s].ppp.phase = sess_local[s].lcp_authtype ? Authenticate : Network;
342
343 LOG(3, s, t, "LCP: Opened, phase %s\n", ppp_phase(session[s].ppp.phase));
344
345 // LCP now Opened
346 change_state(s, lcp, Opened);
347
348 if (session[s].ppp.phase == Authenticate)
349 {
350 if (sess_local[s].lcp_authtype == AUTHCHAP)
351 sendchap(s, t);
352 }
353 else
354 {
355 // This-Layer-Up
356 sendipcp(s, t);
357 change_state(s, ipcp, RequestSent);
358 // move to passive state for IPv6 (if configured), CCP
359 if (config->ipv6_prefix.s6_addr[0])
360 change_state(s, ipv6cp, Stopped);
361 else
362 change_state(s, ipv6cp, Closed);
363
364 change_state(s, ccp, Stopped);
365 }
366 }
367
368 static void lcp_restart(sessionidt s)
369 {
370 session[s].ppp.phase = Establish;
371 // This-Layer-Down
372 change_state(s, ipcp, Dead);
373 change_state(s, ipv6cp, Dead);
374 change_state(s, ccp, Dead);
375 }
376
377 static uint8_t *ppp_conf_rej(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
378 uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option)
379 {
380 if (!*response || **response != ConfigRej)
381 {
382 queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype);
383 if (!queued)
384 return 0;
385
386 *queued = ConfigRej;
387 queued += 4;
388 }
389
390 if ((queued - buf + option[1]) > blen)
391 {
392 LOG(2, s, session[s].tunnel, "PPP overflow for ConfigRej (proto %u, option %u).\n", mtype, *option);
393 return 0;
394 }
395
396 memcpy(queued, option, option[1]);
397 return queued + option[1];
398 }
399
400 static uint8_t *ppp_conf_nak(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
401 uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option,
402 uint8_t *value, size_t vlen)
403 {
404 int *nak_sent;
405 switch (mtype)
406 {
407 case PPPLCP: nak_sent = &sess_local[s].lcp.nak_sent; break;
408 case PPPIPCP: nak_sent = &sess_local[s].ipcp.nak_sent; break;
409 case PPPIPV6CP: nak_sent = &sess_local[s].ipv6cp.nak_sent; break;
410 default: return 0; // ?
411 }
412
413 if (*response && **response != ConfigNak)
414 {
415 if (*nak_sent < config->ppp_max_failure) // reject queued
416 return queued;
417
418 return ppp_conf_rej(s, buf, blen, mtype, response, 0, packet, option);
419 }
420
421 if (!*response)
422 {
423 if (*nak_sent >= config->ppp_max_failure)
424 return ppp_conf_rej(s, buf, blen, mtype, response, 0, packet, option);
425
426 queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype);
427 if (!queued)
428 return 0;
429
430 (*nak_sent)++;
431 *queued = ConfigNak;
432 queued += 4;
433 }
434
435 if ((queued - buf + vlen + 2) > blen)
436 {
437 LOG(2, s, session[s].tunnel, "PPP overflow for ConfigNak (proto %u, option %u).\n", mtype, *option);
438 return 0;
439 }
440
441 *queued++ = *option;
442 *queued++ = vlen + 2;
443 memcpy(queued, value, vlen);
444 return queued + vlen;
445 }
446
447 static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
448 char *pname, uint8_t *p, uint16_t l, uint8_t *buf, size_t size)
449 {
450 uint8_t *q;
451 int mru = session[s].mru;
452 if (mru < MINMTU) mru = MINMTU;
453 if (mru > size) mru = size;
454
455 l += 4;
456 if (l > mru) l = mru;
457
458 q = makeppp(buf, size, 0, 0, s, t, proto);
459 if (!q) return;
460
461 *q = CodeRej;
462 *(q + 1) = ++sess_local[s].lcp_ident;
463 *(uint16_t *)(q + 2) = htons(l);
464 memcpy(q + 4, p, l - 4);
465
466 LOG(2, s, t, "Unexpected %s code %s\n", pname, ppp_code(*p));
467 LOG(3, s, t, "%s: send %s\n", pname, ppp_code(*q));
468 if (config->debug > 3) dumplcp(q, l);
469
470 tunnelsend(buf, l + (q - buf), t);
471 }
472
473 // Process LCP messages
474 void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
475 {
476 uint8_t b[MAXETHER];
477 uint8_t *q = NULL;
478 uint16_t hl;
479
480 CSTAT(processlcp);
481
482 LOG_HEX(5, "LCP", p, l);
483 if (l < 4)
484 {
485 LOG(1, s, t, "Short LCP %d bytes\n", l);
486 STAT(tunnel_rx_errors);
487 return ;
488 }
489
490 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
491 {
492 LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
493 STAT(tunnel_rx_errors);
494 return ;
495 }
496 l = hl;
497
498 if (session[s].die) // going down...
499 return;
500
501 LOG((*p == EchoReq || *p == EchoReply) ? 4 : 3, s, t,
502 "LCP: recv %s\n", ppp_code(*p));
503
504 if (config->debug > 3) dumplcp(p, l);
505
506 if (*p == ConfigAck)
507 {
508 int x = l - 4;
509 uint8_t *o = (p + 4);
510 int authtype = 0;
511
512 while (x > 2)
513 {
514 int type = o[0];
515 int length = o[1];
516
517 if (length == 0 || type == 0 || x < length) break;
518 switch (type)
519 {
520 case 3: // Authentication-Protocol
521 {
522 int proto = ntohs(*(uint16_t *)(o + 2));
523 if (proto == PPPPAP)
524 authtype = AUTHPAP;
525 else if (proto == PPPCHAP && *(o + 4) == 5)
526 authtype = AUTHCHAP;
527 }
528
529 break;
530 }
531 x -= length;
532 o += length;
533 }
534
535 if (!session[s].ip && authtype)
536 sess_local[s].lcp_authtype = authtype;
537
538 switch (session[s].ppp.lcp)
539 {
540 case RequestSent:
541 initialise_restart_count(s, lcp);
542 change_state(s, lcp, AckReceived);
543 break;
544
545 case AckReceived:
546 case Opened:
547 LOG(2, s, t, "LCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
548 if (session[s].ppp.lcp == Opened)
549 lcp_restart(s);
550
551 sendlcp(s, t);
552 change_state(s, lcp, RequestSent);
553 break;
554
555 case AckSent:
556 lcp_open(s, t);
557 break;
558
559 default:
560 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
561 }
562 }
563 else if (*p == ConfigReq)
564 {
565 int x = l - 4;
566 uint8_t *o = (p + 4);
567 uint8_t *response = 0;
568 static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
569 static uint8_t authproto[5];
570
571 while (x > 2)
572 {
573 int type = o[0];
574 int length = o[1];
575
576 if (length == 0 || type == 0 || x < length) break;
577 switch (type)
578 {
579 case 1: // Maximum-Receive-Unit
580 {
581 uint16_t mru = ntohs(*(uint16_t *)(o + 2));
582 if (mru >= MINMTU)
583 {
584 session[s].mru = mru;
585 cluster_send_session(s);
586 break;
587 }
588
589 LOG(3, s, t, " Remote requesting MRU of %u. Rejecting.\n", mru);
590 mru = htons(MRU);
591 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
592 }
593 break;
594
595 case 2: // Async-Control-Character-Map
596 if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
597 break;
598
599 LOG(3, s, t, " Remote requesting asyncmap. Rejecting.\n");
600 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, asyncmap, sizeof(asyncmap));
601 break;
602
603 case 3: // Authentication-Protocol
604 {
605 int proto = ntohs(*(uint16_t *)(o + 2));
606 char proto_name[] = "0x0000";
607 int alen;
608
609 if (proto == PPPPAP)
610 {
611 if (config->radius_authtypes & AUTHPAP)
612 {
613 sess_local[s].lcp_authtype = AUTHPAP;
614 break;
615 }
616
617 strcpy(proto_name, "PAP");
618 }
619 else if (proto == PPPCHAP)
620 {
621 if (config->radius_authtypes & AUTHCHAP
622 && *(o + 4) == 5) // MD5
623 {
624 sess_local[s].lcp_authtype = AUTHCHAP;
625 break;
626 }
627
628 strcpy(proto_name, "CHAP");
629 }
630 else
631 sprintf(proto_name, "%#4.4x", proto);
632
633 LOG(3, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
634
635 alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
636 if (alen < 2) break; // paranoia
637
638 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
639 if (q && *response == ConfigNak &&
640 config->radius_authtypes != config->radius_authprefer)
641 {
642 // alternate type
643 alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
644 if (alen < 2) break;
645 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
646 }
647
648 break;
649 }
650 break;
651
652 case 4: // Quality-Protocol
653 case 5: // Magic-Number
654 case 7: // Protocol-Field-Compression
655 case 8: // Address-And-Control-Field-Compression
656 break;
657
658 default: // Reject any unknown options
659 LOG(3, s, t, " Rejecting unknown PPP LCP option %d\n", type);
660 q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
661 }
662 x -= length;
663 o += length;
664 }
665
666 if (response)
667 {
668 l = q - response; // LCP packet length
669 *((uint16_t *) (response + 2)) = htons(l); // update header
670 }
671 else
672 {
673 // Send packet back as ConfigAck
674 response = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
675 if (!response) return;
676 *response = ConfigAck;
677 }
678
679 switch (session[s].ppp.lcp)
680 {
681 case Closed:
682 response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
683 if (!response) return;
684 *response = TerminateAck;
685 *((uint16_t *) (response + 2)) = htons(l = 4);
686 break;
687
688 case Stopped:
689 initialise_restart_count(s, lcp);
690 sendlcp(s, t);
691 if (*response == ConfigAck)
692 change_state(s, lcp, AckSent);
693 else
694 change_state(s, lcp, RequestSent);
695
696 break;
697
698 case RequestSent:
699 if (*response == ConfigAck)
700 change_state(s, lcp, AckSent);
701
702 break;
703
704 case AckReceived:
705 if (*response == ConfigAck)
706 lcp_open(s, t);
707
708 break;
709
710 case Opened:
711 lcp_restart(s);
712 sendlcp(s, t);
713 /* fallthrough */
714
715 case AckSent:
716 if (*response == ConfigAck)
717 change_state(s, lcp, AckSent);
718 else
719 change_state(s, lcp, RequestSent);
720
721 break;
722
723 default:
724 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
725 return;
726 }
727
728 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
729 if (config->debug > 3) dumplcp(response, l);
730
731 tunnelsend(b, l + (response - b), t);
732 }
733 else if (*p == ConfigNak || *p == ConfigRej)
734 {
735 int x = l - 4;
736 uint8_t *o = (p + 4);
737 int authtype = -1;
738
739 while (x > 2)
740 {
741 int type = o[0];
742 int length = o[1];
743
744 if (length == 0 || type == 0 || x < length) break;
745 switch (type)
746 {
747 case 1: // Maximum-Receive-Unit
748 if (*p == ConfigNak)
749 {
750 sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
751 LOG(3, s, t, " Remote requested MRU of %u\n", sess_local[s].ppp_mru);
752 }
753 else
754 {
755 sess_local[s].ppp_mru = 0;
756 LOG(3, s, t, " Remote rejected MRU negotiation\n");
757 }
758
759 break;
760
761 case 3: // Authentication-Protocol
762 if (authtype > 0)
763 break;
764
765 if (*p == ConfigNak)
766 {
767 int proto = ntohs(*(uint16_t *)(o + 2));
768 if (proto == PPPPAP)
769 {
770 authtype = config->radius_authtypes & AUTHPAP;
771 LOG(3, s, t, " Remote requested PAP authentication...%sing\n",
772 authtype ? "accept" : "reject");
773 }
774 else if (proto == PPPCHAP && *(o + 4) == 5)
775 {
776 authtype = config->radius_authtypes & AUTHCHAP;
777 LOG(3, s, t, " Remote requested CHAP authentication...%sing\n",
778 authtype ? "accept" : "reject");
779 }
780 else
781 {
782 LOG(3, s, t, " Rejecting unsupported authentication %#4x\n",
783 proto);
784 }
785 }
786 else
787 {
788 LOG(2, s, t, "LCP: remote rejected auth negotiation\n");
789 authtype = 0; // shutdown
790 }
791
792 break;
793
794 case 5: // Magic-Number
795 if (*p == ConfigNak)
796 {
797 session[s].magic = ntohl(*(uint32_t *)(o + 2));
798 LOG(3, s, t, " Remote requested magic-no %x\n", session[s].magic);
799 if (!session[s].magic) session[s].magic = time_now; // Netgear DG814 sends zero??
800 cluster_send_session(s);
801 break;
802 }
803 // ConfigRej: fallthrough
804
805 default:
806 LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
807 sessionshutdown(s, "Unable to negotiate LCP.", 3, 0);
808 return;
809 }
810 x -= length;
811 o += length;
812 }
813
814 if (!authtype)
815 {
816 sessionshutdown(s, "Unsupported authentication.", 3, 0);
817 return;
818 }
819
820 if (authtype > 0)
821 sess_local[s].lcp_authtype = authtype;
822
823 switch (session[s].ppp.lcp)
824 {
825 case Closed:
826 case Stopped:
827 {
828 uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
829 if (!response) return;
830 *response = TerminateAck;
831 *((uint16_t *) (response + 2)) = htons(l = 4);
832
833 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
834 if (config->debug > 3) dumplcp(response, l);
835
836 tunnelsend(b, l + (response - b), t);
837 }
838 break;
839
840 case RequestSent:
841 case AckSent:
842 initialise_restart_count(s, lcp);
843 sendlcp(s, t);
844 break;
845
846 case AckReceived:
847 LOG(2, s, t, "LCP: ConfigNak in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
848 sendlcp(s, t);
849 break;
850
851 case Opened:
852 lcp_restart(s);
853 sendlcp(s, t);
854 break;
855
856 default:
857 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
858 return;
859 }
860 }
861 else if (*p == TerminateReq)
862 {
863 *p = TerminateAck; // close
864 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
865 if (!q) return;
866
867 LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
868 if (config->debug > 3) dumplcp(q, l);
869
870 tunnelsend(b, l + (q - b), t); // send it
871 sessionshutdown(s, "Remote end closed connection.", 3, 0);
872 }
873 else if (*p == TerminateAck)
874 {
875 sessionshutdown(s, "Connection closed.", 3, 0);
876 }
877 else if (*p == ProtocolRej)
878 {
879 uint16_t proto = 0;
880
881 if (l > 4)
882 {
883 proto = *(p+4);
884 if (l > 5 && !(proto & 1))
885 {
886 proto <<= 8;
887 proto |= *(p+5);
888 }
889 }
890
891 if (proto == PPPIPV6CP)
892 {
893 LOG(3, s, t, "IPv6 rejected\n");
894 change_state(s, ipv6cp, Closed);
895 }
896 else
897 {
898 LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
899 }
900 }
901 else if (*p == EchoReq)
902 {
903 *p = EchoReply; // reply
904 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
905 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
906 if (!q) return;
907
908 LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
909 if (config->debug > 3) dumplcp(q, l);
910
911 tunnelsend(b, l + (q - b), t); // send it
912 }
913 else if (*p == EchoReply)
914 {
915 // Ignore it, last_packet time is set earlier than this.
916 }
917 else if (*p != CodeRej)
918 {
919 ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
920 }
921 }
922
923 static void ipcp_open(sessionidt s, tunnelidt t)
924 {
925 LOG(3, s, t, "IPCP: Opened, session is now active\n");
926
927 change_state(s, ipcp, Opened);
928
929 if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
930 {
931 uint16_t r = radiusnew(s);
932 if (r)
933 {
934 radiussend(r, RADIUSSTART); // send radius start
935
936 // don't send further Start records if IPCP is restarted
937 session[s].flags |= SESSION_STARTED;
938 cluster_send_session(s);
939 }
940 }
941
942 // start IPv6 if configured and still in passive state
943 if (session[s].ppp.ipv6cp == Stopped)
944 {
945 sendipv6cp(s, t);
946 change_state(s, ipv6cp, RequestSent);
947 }
948 }
949
950 // Process IPCP messages
951 void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
952 {
953 uint8_t b[MAXETHER];
954 uint8_t *q = 0;
955 uint16_t hl;
956
957 CSTAT(processipcp);
958
959 LOG_HEX(5, "IPCP", p, l);
960 if (l < 5)
961 {
962 LOG(1, s, t, "Short IPCP %d bytes\n", l);
963 STAT(tunnel_rx_errors);
964 return ;
965 }
966
967 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
968 {
969 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
970 STAT(tunnel_rx_errors);
971 return ;
972 }
973 l = hl;
974
975 if (session[s].ppp.phase < Network)
976 {
977 LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
978 return;
979 }
980
981 LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
982
983 if (*p == ConfigAck)
984 {
985 switch (session[s].ppp.ipcp)
986 {
987 case RequestSent:
988 initialise_restart_count(s, ipcp);
989 change_state(s, ipcp, AckReceived);
990 break;
991
992 case AckReceived:
993 case Opened:
994 LOG(2, s, t, "IPCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
995 sendipcp(s, t);
996 change_state(s, ipcp, RequestSent);
997 break;
998
999 case AckSent:
1000 ipcp_open(s, t);
1001 break;
1002
1003 default:
1004 LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1005 }
1006 }
1007 else if (*p == ConfigReq)
1008 {
1009 uint8_t *response = 0;
1010 uint8_t *o = p + 4;
1011 int length = l - 4;
1012 int gotip = 0;
1013 in_addr_t addr;
1014
1015 while (length > 2)
1016 {
1017 if (!o[1] || o[1] > length) return;
1018
1019 switch (*o)
1020 {
1021 case 3: // ip address
1022 gotip++; // seen address
1023 if (o[1] != 6) return;
1024
1025 addr = htonl(session[s].ip);
1026 if (memcmp(o + 2, &addr, (sizeof addr)))
1027 {
1028 uint8_t *oq = q;
1029 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1030 if (!q || (q != oq && *response == ConfigRej))
1031 {
1032 sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
1033 return;
1034 }
1035 }
1036
1037 break;
1038
1039 case 129: // primary DNS
1040 if (o[1] != 6) return;
1041
1042 addr = htonl(session[s].dns1);
1043 if (memcmp(o + 2, &addr, (sizeof addr)))
1044 {
1045 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1046 if (!q) return;
1047 }
1048
1049 break;
1050
1051 case 131: // secondary DNS
1052 if (o[1] != 6) return;
1053
1054 addr = htonl(session[s].dns2);
1055 if (memcmp(o + 2, &addr, sizeof(addr)))
1056 {
1057 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1058 if (!q) return;
1059 }
1060
1061 break;
1062
1063 default:
1064 LOG(2, s, t, " Rejecting PPP IPCP Option type %d\n", *o);
1065 q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
1066 if (!q) return;
1067 }
1068
1069 length -= o[1];
1070 o += o[1];
1071 }
1072
1073 if (response)
1074 {
1075 l = q - response; // IPCP packet length
1076 *((uint16_t *) (response + 2)) = htons(l); // update header
1077 }
1078 else if (gotip)
1079 {
1080 // Send packet back as ConfigAck
1081 response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1082 if (!response) return;
1083 *response = ConfigAck;
1084 }
1085 else
1086 {
1087 LOG(1, s, t, "No IP in IPCP request\n");
1088 STAT(tunnel_rx_errors);
1089 return;
1090 }
1091
1092 switch (session[s].ppp.ipcp)
1093 {
1094 case Closed:
1095 response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
1096 if (!response) return;
1097 *response = TerminateAck;
1098 *((uint16_t *) (response + 2)) = htons(l = 4);
1099 break;
1100
1101 case Stopped:
1102 initialise_restart_count(s, ipcp);
1103 sendipcp(s, t);
1104 if (*response == ConfigAck)
1105 change_state(s, ipcp, AckSent);
1106 else
1107 change_state(s, ipcp, RequestSent);
1108
1109 break;
1110
1111 case RequestSent:
1112 if (*response == ConfigAck)
1113 change_state(s, ipcp, AckSent);
1114
1115 break;
1116
1117 case AckReceived:
1118 if (*response == ConfigAck)
1119 ipcp_open(s, t);
1120
1121 break;
1122
1123 case Opened:
1124 initialise_restart_count(s, ipcp);
1125 sendipcp(s, t);
1126 /* fallthrough */
1127
1128 case AckSent:
1129 if (*response == ConfigAck)
1130 change_state(s, ipcp, AckSent);
1131 else
1132 change_state(s, ipcp, RequestSent);
1133
1134 break;
1135
1136 default:
1137 LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1138 return;
1139 }
1140
1141 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
1142 tunnelsend(b, l + (response - b), t);
1143 }
1144 else if (*p == TerminateReq)
1145 {
1146 *p = TerminateAck;
1147 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1148 if (!q) return;
1149 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
1150 tunnelsend(b, l + (q - b), t);
1151 change_state(s, ipcp, Stopped);
1152 }
1153 else if (*p != CodeRej)
1154 {
1155 ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
1156 }
1157 }
1158
1159 static void ipv6cp_open(sessionidt s, tunnelidt t)
1160 {
1161 LOG(3, s, t, "IPV6CP: Opened\n");
1162
1163 change_state(s, ipv6cp, Opened);
1164 if (session[s].ipv6prefixlen)
1165 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
1166
1167 // Send an initial RA (TODO: Should we send these regularly?)
1168 send_ipv6_ra(s, t, NULL);
1169 }
1170
1171 // Process IPV6CP messages
1172 void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1173 {
1174 uint8_t b[MAXETHER];
1175 uint8_t *q = 0;
1176 uint16_t hl;
1177
1178 CSTAT(processipv6cp);
1179
1180 LOG_HEX(5, "IPV6CP", p, l);
1181 if (l < 4)
1182 {
1183 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
1184 STAT(tunnel_rx_errors);
1185 return ;
1186 }
1187
1188 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
1189 {
1190 LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
1191 STAT(tunnel_rx_errors);
1192 return ;
1193 }
1194 l = hl;
1195
1196 if (session[s].ppp.phase < Network)
1197 {
1198 LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1199 return;
1200 }
1201
1202 LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
1203
1204 if (!session[s].ip)
1205 {
1206 LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
1207 return; // need IPCP to complete...
1208 }
1209
1210 if (*p == ConfigAck)
1211 {
1212 switch (session[s].ppp.ipv6cp)
1213 {
1214 case RequestSent:
1215 initialise_restart_count(s, ipv6cp);
1216 change_state(s, ipv6cp, AckReceived);
1217 break;
1218
1219 case AckReceived:
1220 case Opened:
1221 LOG(2, s, t, "IPV6CP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
1222 sendipv6cp(s, t);
1223 change_state(s, ipv6cp, RequestSent);
1224 break;
1225
1226 case AckSent:
1227 ipv6cp_open(s, t);
1228 break;
1229
1230 default:
1231 LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1232 }
1233 }
1234 else if (*p == ConfigReq)
1235 {
1236 uint8_t *response = 0;
1237 uint8_t *o = p + 4;
1238 int length = l - 4;
1239 int gotip = 0;
1240 uint8_t ident[8];
1241
1242 while (length > 2)
1243 {
1244 if (!o[1] || o[1] > length) return;
1245
1246 switch (*o)
1247 {
1248 case 1: // interface identifier
1249 gotip++; // seen address
1250 if (o[1] != 10) return;
1251
1252 *(uint32_t *) ident = htonl(session[s].ip);
1253 *(uint32_t *) (ident + 4) = 0;
1254
1255 if (memcmp(o + 2, ident, sizeof(ident)))
1256 {
1257 q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
1258 if (!q) return;
1259 }
1260
1261 break;
1262
1263 default:
1264 LOG(2, s, t, " Rejecting PPP IPV6CP Option type %d\n", *o);
1265 q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
1266 if (!q) return;
1267 }
1268
1269 length -= o[1];
1270 o += o[1];
1271 }
1272
1273 if (response)
1274 {
1275 l = q - response; // IPV6CP packet length
1276 *((uint16_t *) (response + 2)) = htons(l); // update header
1277 }
1278 else if (gotip)
1279 {
1280 // Send packet back as ConfigAck
1281 response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1282 if (!response) return;
1283 *response = ConfigAck;
1284 }
1285 else
1286 {
1287 LOG(1, s, t, "No interface identifier in IPV6CP request\n");
1288 STAT(tunnel_rx_errors);
1289 return;
1290 }
1291
1292 switch (session[s].ppp.ipv6cp)
1293 {
1294 case Closed:
1295 response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
1296 if (!response) return;
1297 *response = TerminateAck;
1298 *((uint16_t *) (response + 2)) = htons(l = 4);
1299 break;
1300
1301 case Stopped:
1302 initialise_restart_count(s, ipv6cp);
1303 sendipv6cp(s, t);
1304 if (*response == ConfigAck)
1305 change_state(s, ipv6cp, AckSent);
1306 else
1307 change_state(s, ipv6cp, RequestSent);
1308
1309 break;
1310
1311 case RequestSent:
1312 if (*response == ConfigAck)
1313 change_state(s, ipv6cp, AckSent);
1314
1315 break;
1316
1317 case AckReceived:
1318 if (*response == ConfigAck)
1319 ipv6cp_open(s, t);
1320
1321 break;
1322
1323 case Opened:
1324 initialise_restart_count(s, ipv6cp);
1325 sendipv6cp(s, t);
1326 /* fallthrough */
1327
1328 case AckSent:
1329 if (*response == ConfigAck)
1330 change_state(s, ipv6cp, AckSent);
1331 else
1332 change_state(s, ipv6cp, RequestSent);
1333
1334 break;
1335
1336 default:
1337 LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1338 return;
1339 }
1340
1341 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
1342 tunnelsend(b, l + (response - b), t);
1343 }
1344 else if (*p == TerminateReq)
1345 {
1346 *p = TerminateAck;
1347 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1348 if (!q) return;
1349 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
1350 tunnelsend(b, l + (q - b), t);
1351 change_state(s, ipv6cp, Stopped);
1352 }
1353 else if (*p != CodeRej)
1354 {
1355 ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
1356 }
1357 }
1358
1359 // process IP packet received
1360 //
1361 // This MUST be called with at least 4 byte behind 'p'.
1362 // (i.e. this routine writes to p[-4]).
1363 void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1364 {
1365 in_addr_t ip;
1366
1367 CSTAT(processipin);
1368
1369 LOG_HEX(5, "IP", p, l);
1370
1371 if (l < 20)
1372 {
1373 LOG(1, s, t, "IP packet too short %d\n", l);
1374 STAT(tunnel_rx_errors);
1375 return ;
1376 }
1377
1378 ip = ntohl(*(uint32_t *)(p + 12));
1379
1380 if (l > MAXETHER)
1381 {
1382 LOG(1, s, t, "IP packet too long %d\n", l);
1383 STAT(tunnel_rx_errors);
1384 return ;
1385 }
1386
1387 if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
1388 return;
1389
1390 // no spoof (do sessionbyip to handled statically routed subnets)
1391 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
1392 {
1393 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
1394 return;
1395 }
1396
1397 // run access-list if any
1398 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
1399 return;
1400
1401 // adjust MSS on SYN and SYN,ACK packets with options
1402 if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
1403 {
1404 int ihl = (p[0] & 0xf) * 4; // length of IP header
1405 if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
1406 adjust_tcp_mss(s, t, p, l, p + ihl);
1407 }
1408
1409 // Add on the tun header
1410 p -= 4;
1411 *(uint32_t *) p = htonl(PKTIP);
1412 l += 4;
1413
1414 // Are we throttled and a slave?
1415 if (session[s].tbf_in && !config->cluster_iam_master) {
1416 // Pass it to the master for handling.
1417 master_throttle_packet(session[s].tbf_in, p, l);
1418 return;
1419 }
1420
1421 // Are we throttled and a master??
1422 if (session[s].tbf_in && config->cluster_iam_master) {
1423 // Actually handle the throttled packets.
1424 tbf_queue_packet(session[s].tbf_in, p, l);
1425 return;
1426 }
1427
1428 // send to ethernet
1429 if (tun_write(p, l) < 0)
1430 {
1431 STAT(tun_tx_errors);
1432 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1433 l, strerror(errno), tunfd, p);
1434
1435 return;
1436 }
1437
1438 p += 4;
1439 l -= 4;
1440
1441 if (session[s].snoop_ip && session[s].snoop_port)
1442 {
1443 // Snooping this session
1444 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1445 }
1446
1447 increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1448 session[s].cin_delta += l;
1449 session[s].pin++;
1450
1451 sess_local[s].cin += l;
1452 sess_local[s].pin++;
1453
1454 eth_tx += l;
1455
1456 STAT(tun_tx_packets);
1457 INC_STAT(tun_tx_bytes, l);
1458 }
1459
1460 // process IPv6 packet received
1461 //
1462 // This MUST be called with at least 4 byte behind 'p'.
1463 // (i.e. this routine writes to p[-4]).
1464 void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1465 {
1466 struct in6_addr ip;
1467 in_addr_t ipv4;
1468
1469 CSTAT(processipv6in);
1470
1471 LOG_HEX(5, "IPv6", p, l);
1472
1473 ip = *(struct in6_addr *) (p + 8);
1474 ipv4 = ntohl(*(uint32_t *)(p + 16));
1475
1476 if (l > MAXETHER)
1477 {
1478 LOG(1, s, t, "IP packet too long %d\n", l);
1479 STAT(tunnel_rx_errors);
1480 return ;
1481 }
1482
1483 if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
1484 return;
1485
1486 // no spoof
1487 if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1488 {
1489 char str[INET6_ADDRSTRLEN];
1490 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1491 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1492 return;
1493 }
1494
1495 // Check if it's a Router Solicition message.
1496 if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1497 *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1498 *(uint32_t *)(p + 34) == 0 &&
1499 *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1500 LOG(3, s, t, "Got IPv6 RS\n");
1501 send_ipv6_ra(s, t, &ip);
1502 return;
1503 }
1504
1505 // Add on the tun header
1506 p -= 4;
1507 *(uint32_t *) p = htonl(PKTIPV6);
1508 l += 4;
1509
1510 // Are we throttled and a slave?
1511 if (session[s].tbf_in && !config->cluster_iam_master) {
1512 // Pass it to the master for handling.
1513 master_throttle_packet(session[s].tbf_in, p, l);
1514 return;
1515 }
1516
1517 // Are we throttled and a master??
1518 if (session[s].tbf_in && config->cluster_iam_master) {
1519 // Actually handle the throttled packets.
1520 tbf_queue_packet(session[s].tbf_in, p, l);
1521 return;
1522 }
1523
1524 // send to ethernet
1525 if (tun_write(p, l) < 0)
1526 {
1527 STAT(tun_tx_errors);
1528 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1529 l, strerror(errno), tunfd, p);
1530
1531 return;
1532 }
1533
1534 p += 4;
1535 l -= 4;
1536
1537 if (session[s].snoop_ip && session[s].snoop_port)
1538 {
1539 // Snooping this session
1540 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1541 }
1542
1543 increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1544 session[s].cin_delta += l;
1545 session[s].pin++;
1546
1547 sess_local[s].cin += l;
1548 sess_local[s].pin++;
1549
1550 eth_tx += l;
1551
1552 STAT(tun_tx_packets);
1553 INC_STAT(tun_tx_bytes, l);
1554 }
1555
1556 //
1557 // Helper routine for the TBF filters.
1558 // Used to send queued data in from the user.
1559 //
1560 void send_ipin(sessionidt s, uint8_t *buf, int len)
1561 {
1562 LOG_HEX(5, "IP in throttled", buf, len);
1563
1564 if (write(tunfd, buf, len) < 0)
1565 {
1566 STAT(tun_tx_errors);
1567 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1568 len, strerror(errno), tunfd, buf);
1569
1570 return;
1571 }
1572
1573 buf += 4;
1574 len -= 4;
1575
1576 if (session[s].snoop_ip && session[s].snoop_port)
1577 {
1578 // Snooping this session
1579 snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
1580 }
1581
1582 // Increment packet counters
1583 increment_counter(&session[s].cin, &session[s].cin_wrap, len);
1584 session[s].cin_delta += len;
1585 session[s].pin++;
1586
1587 sess_local[s].cin += len;
1588 sess_local[s].pin++;
1589
1590 eth_tx += len;
1591
1592 STAT(tun_tx_packets);
1593 INC_STAT(tun_tx_bytes, len - 4);
1594 }
1595
1596
1597 // Process CCP messages
1598 void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1599 {
1600 uint8_t b[MAXETHER];
1601 uint8_t *q;
1602
1603 CSTAT(processccp);
1604
1605 LOG_HEX(5, "CCP", p, l);
1606
1607 if (session[s].ppp.phase < Network)
1608 {
1609 LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1610 return;
1611 }
1612
1613 if (l < 1)
1614 {
1615 LOG(1, s, t, "Short CCP packet\n");
1616 STAT(tunnel_rx_errors);
1617 }
1618
1619 LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
1620 if (*p == ConfigAck)
1621 {
1622 switch (session[s].ppp.ccp)
1623 {
1624 case RequestSent:
1625 initialise_restart_count(s, ccp);
1626 change_state(s, ccp, AckReceived);
1627 break;
1628
1629 case AckReceived:
1630 case Opened:
1631 LOG(2, s, t, "CCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
1632 sendccp(s, t);
1633 change_state(s, ccp, RequestSent);
1634 break;
1635
1636 case AckSent:
1637 LOG(3, s, t, "CCP: Opened\n");
1638 change_state(s, ccp, Opened);
1639 break;
1640
1641 default:
1642 LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1643 }
1644 }
1645 else if (*p == ConfigReq)
1646 {
1647 if (l < 6) // accept no compression
1648 *p = ConfigAck;
1649 else // compression requested--reject
1650 *p = ConfigRej;
1651
1652 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1653 if (!q) return;
1654
1655 switch (session[s].ppp.ccp)
1656 {
1657 case Closed:
1658 q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
1659 if (!q) return;
1660 *q = TerminateAck;
1661 *((uint16_t *) (q + 2)) = htons(l = 4);
1662 break;
1663
1664 case Stopped:
1665 initialise_restart_count(s, ccp);
1666 sendccp(s, t);
1667 if (*q == ConfigAck)
1668 change_state(s, ccp, AckSent);
1669 else
1670 change_state(s, ccp, RequestSent);
1671
1672 break;
1673
1674 case RequestSent:
1675 if (*q == ConfigAck)
1676 change_state(s, ccp, AckSent);
1677
1678 break;
1679
1680 case AckReceived:
1681 if (*q == ConfigAck)
1682 change_state(s, ccp, Opened);
1683
1684 break;
1685
1686 case Opened:
1687 initialise_restart_count(s, ccp);
1688 sendccp(s, t);
1689 /* fallthrough */
1690
1691 case AckSent:
1692 if (*q == ConfigAck)
1693 change_state(s, ccp, AckSent);
1694 else
1695 change_state(s, ccp, RequestSent);
1696
1697 break;
1698
1699 default:
1700 LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1701 return;
1702 }
1703
1704 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1705 tunnelsend(b, l + (q - b), t);
1706 }
1707 else if (*p == TerminateReq)
1708 {
1709 *p = TerminateAck;
1710 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1711 if (!q) return;
1712 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1713 tunnelsend(b, l + (q - b), t);
1714 change_state(s, ccp, Stopped);
1715 }
1716 else if (*p != CodeRej)
1717 {
1718 ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
1719 }
1720 }
1721
1722 // send a CHAP challenge
1723 void sendchap(sessionidt s, tunnelidt t)
1724 {
1725 uint8_t b[MAXETHER];
1726 uint16_t r;
1727 uint8_t *q;
1728
1729 CSTAT(sendchap);
1730
1731 r = radiusnew(s);
1732 if (!r)
1733 {
1734 LOG(1, s, t, "No RADIUS to send challenge\n");
1735 STAT(tunnel_tx_errors);
1736 return;
1737 }
1738
1739 LOG(1, s, t, "Send CHAP challenge\n");
1740
1741 radius[r].chap = 1; // CHAP not PAP
1742 radius[r].id++;
1743 if (radius[r].state != RADIUSCHAP)
1744 radius[r].try = 0;
1745
1746 radius[r].state = RADIUSCHAP;
1747 radius[r].retry = backoff(radius[r].try++);
1748 if (radius[r].try > 5)
1749 {
1750 sessionshutdown(s, "CHAP timeout.", 3, 0);
1751 STAT(tunnel_tx_errors);
1752 return ;
1753 }
1754 q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
1755 if (!q) return;
1756
1757 *q = 1; // challenge
1758 q[1] = radius[r].id; // ID
1759 q[4] = 16; // value size (size of challenge)
1760 memcpy(q + 5, radius[r].auth, 16); // challenge
1761 strcpy((char *) q + 21, hostname); // our name
1762 *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1763 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1764 }
1765
1766 // fill in a L2TP message with a PPP frame,
1767 // copies existing PPP message and changes magic number if seen
1768 // returns start of PPP frame
1769 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
1770 {
1771 if (size < 12) // Need more space than this!!
1772 {
1773 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1774 return NULL;
1775 }
1776
1777 *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1778 *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1779 *(uint16_t *) (b + 4) = htons(session[s].far); // session
1780 b += 6;
1781 if (mtype == PPPLCP || !(session[s].flags & SESSION_ACFC))
1782 {
1783 *(uint16_t *) b = htons(0xFF03); // HDLC header
1784 b += 2;
1785 }
1786 if (mtype < 0x100 && session[s].flags & SESSION_PFC)
1787 *b++ = mtype;
1788 else
1789 {
1790 *(uint16_t *) b = htons(mtype);
1791 b += 2;
1792 }
1793
1794 if (l + 12 > size)
1795 {
1796 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1797 return NULL;
1798 }
1799
1800 if (p && l)
1801 memcpy(b, p, l);
1802
1803 return b;
1804 }
1805
1806 static int add_lcp_auth(uint8_t *b, int size, int authtype)
1807 {
1808 int len = 0;
1809 if ((authtype == AUTHCHAP && size < 5) || size < 4)
1810 return 0;
1811
1812 *b++ = 3; // Authentication-Protocol
1813 if (authtype == AUTHCHAP)
1814 {
1815 len = *b++ = 5; // length
1816 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1817 *b++ = 5; // MD5
1818 }
1819 else if (authtype == AUTHPAP)
1820 {
1821 len = *b++ = 4; // length
1822 *(uint16_t *) b = htons(PPPPAP); b += 2;
1823 }
1824 else
1825 {
1826 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1827 }
1828
1829 return len;
1830 }
1831
1832 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1833 void sendlcp(sessionidt s, tunnelidt t)
1834 {
1835 uint8_t b[500], *q, *l;
1836 int authtype = sess_local[s].lcp_authtype;
1837
1838 if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
1839 return;
1840
1841 LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
1842 authtype ? " (" : "",
1843 authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
1844 authtype ? ")" : "");
1845
1846 l = q;
1847 *l++ = ConfigReq;
1848 *l++ = ++sess_local[s].lcp_ident; // ID
1849
1850 l += 2; //Save space for length
1851
1852 if (sess_local[s].ppp_mru)
1853 {
1854 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1855 *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
1856 }
1857
1858 if (authtype)
1859 l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1860
1861 *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1862 *(uint32_t *) l = htonl(session[s].magic);
1863 l += 4;
1864
1865 *(uint16_t *)(q + 2) = htons(l - q); // Length
1866
1867 LOG_HEX(5, "PPPLCP", q, l - q);
1868 if (config->debug > 3) dumplcp(q, l - q);
1869
1870 tunnelsend(b, (l - b), t);
1871 restart_timer(s, lcp);
1872 }
1873
1874 // Send CCP request for no compression
1875 void sendccp(sessionidt s, tunnelidt t)
1876 {
1877 uint8_t b[500], *q;
1878
1879 if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
1880 return;
1881
1882 LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
1883
1884 *q = ConfigReq;
1885 *(q + 1) = ++sess_local[s].lcp_ident; // ID
1886 *(uint16_t *)(q + 2) = htons(4); // Length
1887
1888 LOG_HEX(5, "PPPCCP", q, 4);
1889 tunnelsend(b, (q - b) + 4 , t);
1890 restart_timer(s, ccp);
1891 }
1892
1893 // Reject unknown/unconfigured protocols
1894 void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
1895 {
1896
1897 uint8_t buf[MAXETHER];
1898 uint8_t *q;
1899 int mru = session[s].mru;
1900 if (mru < MINMTU) mru = MINMTU;
1901 if (mru > sizeof(buf)) mru = sizeof(buf);
1902
1903 l += 6;
1904 if (l > mru) l = mru;
1905
1906 q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
1907 if (!q) return;
1908
1909 *q = ProtocolRej;
1910 *(q + 1) = ++sess_local[s].lcp_ident;
1911 *(uint16_t *)(q + 2) = htons(l);
1912 *(uint16_t *)(q + 4) = htons(proto);
1913 memcpy(q + 6, p, l - 6);
1914
1915 if (proto == PPPIPV6CP)
1916 LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
1917 else
1918 LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
1919
1920 tunnelsend(buf, l + (q - buf), t);
1921 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"