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[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.91 2005/12/15 14:23:03 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 uint32_t magicno = 0;
479 uint16_t hl;
480
481 CSTAT(processlcp);
482
483 LOG_HEX(5, "LCP", p, l);
484 if (l < 4)
485 {
486 LOG(1, s, t, "Short LCP %d bytes\n", l);
487 STAT(tunnel_rx_errors);
488 return ;
489 }
490
491 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
492 {
493 LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
494 STAT(tunnel_rx_errors);
495 return ;
496 }
497 l = hl;
498
499 if (session[s].die) // going down...
500 return;
501
502 LOG((*p == EchoReq || *p == EchoReply) ? 4 : 3, s, t,
503 "LCP: recv %s\n", ppp_code(*p));
504
505 if (config->debug > 3) dumplcp(p, l);
506
507 if (*p == ConfigAck)
508 {
509 int x = l - 4;
510 uint8_t *o = (p + 4);
511 int authtype = 0;
512
513 while (x > 2)
514 {
515 int type = o[0];
516 int length = o[1];
517
518 if (length == 0 || type == 0 || x < length) break;
519 switch (type)
520 {
521 case 3: // Authentication-Protocol
522 {
523 int proto = ntohs(*(uint16_t *)(o + 2));
524 if (proto == PPPPAP)
525 authtype = AUTHPAP;
526 else if (proto == PPPCHAP && *(o + 4) == 5)
527 authtype = AUTHCHAP;
528 }
529
530 break;
531 }
532 x -= length;
533 o += length;
534 }
535
536 if (!session[s].ip && authtype)
537 sess_local[s].lcp_authtype = authtype;
538
539 switch (session[s].ppp.lcp)
540 {
541 case RequestSent:
542 initialise_restart_count(s, lcp);
543 change_state(s, lcp, AckReceived);
544 break;
545
546 case AckReceived:
547 case Opened:
548 LOG(2, s, t, "LCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
549 if (session[s].ppp.lcp == Opened)
550 lcp_restart(s);
551
552 sendlcp(s, t);
553 change_state(s, lcp, RequestSent);
554 break;
555
556 case AckSent:
557 lcp_open(s, t);
558 break;
559
560 default:
561 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
562 }
563 }
564 else if (*p == ConfigReq)
565 {
566 int x = l - 4;
567 uint8_t *o = (p + 4);
568 uint8_t *response = 0;
569 static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
570 static uint8_t authproto[5];
571
572 while (x > 2)
573 {
574 int type = o[0];
575 int length = o[1];
576
577 if (length == 0 || type == 0 || x < length) break;
578 switch (type)
579 {
580 case 1: // Maximum-Receive-Unit
581 {
582 uint16_t mru = ntohs(*(uint16_t *)(o + 2));
583 if (mru >= MINMTU)
584 {
585 session[s].mru = mru;
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 5: // Magic-Number
653 magicno = ntohl(*(uint32_t *)(o + 2));
654 break;
655
656 case 4: // Quality-Protocol
657 case 7: // Protocol-Field-Compression
658 case 8: // Address-And-Control-Field-Compression
659 break;
660
661 default: // Reject any unknown options
662 LOG(3, s, t, " Rejecting unknown PPP LCP option %d\n", type);
663 q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
664 }
665 x -= length;
666 o += length;
667 }
668
669 if (response)
670 {
671 l = q - response; // LCP packet length
672 *((uint16_t *) (response + 2)) = htons(l); // update header
673 }
674 else
675 {
676 // Send packet back as ConfigAck
677 response = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
678 if (!response) return;
679 *response = ConfigAck;
680 }
681
682 switch (session[s].ppp.lcp)
683 {
684 case Closed:
685 response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
686 if (!response) return;
687 *response = TerminateAck;
688 *((uint16_t *) (response + 2)) = htons(l = 4);
689 break;
690
691 case Stopped:
692 initialise_restart_count(s, lcp);
693 sendlcp(s, t);
694 if (*response == ConfigAck)
695 change_state(s, lcp, AckSent);
696 else
697 change_state(s, lcp, RequestSent);
698
699 break;
700
701 case RequestSent:
702 if (*response == ConfigAck)
703 change_state(s, lcp, AckSent);
704
705 break;
706
707 case AckReceived:
708 if (*response == ConfigAck)
709 lcp_open(s, t);
710
711 break;
712
713 case Opened:
714 lcp_restart(s);
715 sendlcp(s, t);
716 /* fallthrough */
717
718 case AckSent:
719 if (*response == ConfigAck)
720 change_state(s, lcp, AckSent);
721 else
722 change_state(s, lcp, RequestSent);
723
724 break;
725
726 default:
727 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
728 return;
729 }
730
731 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
732 if (config->debug > 3) dumplcp(response, l);
733
734 tunnelsend(b, l + (response - b), t);
735 }
736 else if (*p == ConfigNak || *p == ConfigRej)
737 {
738 int x = l - 4;
739 uint8_t *o = (p + 4);
740 int authtype = -1;
741
742 while (x > 2)
743 {
744 int type = o[0];
745 int length = o[1];
746
747 if (length == 0 || type == 0 || x < length) break;
748 switch (type)
749 {
750 case 1: // Maximum-Receive-Unit
751 if (*p == ConfigNak)
752 {
753 sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
754 LOG(3, s, t, " Remote requested MRU of %u\n", sess_local[s].ppp_mru);
755 }
756 else
757 {
758 sess_local[s].ppp_mru = 0;
759 LOG(3, s, t, " Remote rejected MRU negotiation\n");
760 }
761
762 break;
763
764 case 3: // Authentication-Protocol
765 if (authtype > 0)
766 break;
767
768 if (*p == ConfigNak)
769 {
770 int proto = ntohs(*(uint16_t *)(o + 2));
771 if (proto == PPPPAP)
772 {
773 authtype = config->radius_authtypes & AUTHPAP;
774 LOG(3, s, t, " Remote requested PAP authentication...%sing\n",
775 authtype ? "accept" : "reject");
776 }
777 else if (proto == PPPCHAP && *(o + 4) == 5)
778 {
779 authtype = config->radius_authtypes & AUTHCHAP;
780 LOG(3, s, t, " Remote requested CHAP authentication...%sing\n",
781 authtype ? "accept" : "reject");
782 }
783 else
784 {
785 LOG(3, s, t, " Rejecting unsupported authentication %#4x\n",
786 proto);
787 }
788 }
789 else
790 {
791 LOG(2, s, t, "LCP: remote rejected auth negotiation\n");
792 authtype = 0; // shutdown
793 }
794
795 break;
796
797 default:
798 LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
799 sessionshutdown(s, "Unable to negotiate LCP.", 3, 0);
800 break;
801 }
802 x -= length;
803 o += length;
804 }
805
806 if (!authtype)
807 {
808 sessionshutdown(s, "Unsupported authentication.", 3, 0);
809 return;
810 }
811
812 if (authtype > 0)
813 sess_local[s].lcp_authtype = authtype;
814
815 switch (session[s].ppp.lcp)
816 {
817 case Closed:
818 case Stopped:
819 {
820 uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
821 if (!response) return;
822 *response = TerminateAck;
823 *((uint16_t *) (response + 2)) = htons(l = 4);
824
825 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
826 if (config->debug > 3) dumplcp(response, l);
827
828 tunnelsend(b, l + (response - b), t);
829 }
830 break;
831
832 case RequestSent:
833 case AckSent:
834 initialise_restart_count(s, lcp);
835 sendlcp(s, t);
836 break;
837
838 case AckReceived:
839 LOG(2, s, t, "LCP: ConfigNak in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
840 sendlcp(s, t);
841 break;
842
843 case Opened:
844 lcp_restart(s);
845 sendlcp(s, t);
846 break;
847
848 default:
849 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
850 return;
851 }
852 }
853 else if (*p == TerminateReq)
854 {
855 *p = TerminateAck; // close
856 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
857 if (!q) return;
858
859 LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
860 if (config->debug > 3) dumplcp(q, l);
861
862 tunnelsend(b, l + (q - b), t); // send it
863 sessionshutdown(s, "Remote end closed connection.", 3, 0);
864 }
865 else if (*p == TerminateAck)
866 {
867 sessionshutdown(s, "Connection closed.", 3, 0);
868 }
869 else if (*p == ProtocolRej)
870 {
871 uint16_t proto = 0;
872
873 if (l > 4)
874 {
875 proto = *(p+4);
876 if (l > 5 && !(proto & 1))
877 {
878 proto <<= 8;
879 proto |= *(p+5);
880 }
881 }
882
883 if (proto == PPPIPV6CP)
884 {
885 LOG(3, s, t, "IPv6 rejected\n");
886 change_state(s, ipv6cp, Closed);
887 }
888 else
889 {
890 LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
891 }
892 }
893 else if (*p == EchoReq)
894 {
895 *p = EchoReply; // reply
896 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
897 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
898 if (!q) return;
899
900 LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
901 if (config->debug > 3) dumplcp(q, l);
902
903 tunnelsend(b, l + (q - b), t); // send it
904 }
905 else if (*p == EchoReply)
906 {
907 // Ignore it, last_packet time is set earlier than this.
908 }
909 else if (*p != CodeRej)
910 {
911 ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
912 }
913 }
914
915 static void ipcp_open(sessionidt s, tunnelidt t)
916 {
917 LOG(3, s, t, "IPCP: Opened, session is now active\n");
918
919 change_state(s, ipcp, Opened);
920
921 if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
922 {
923 uint16_t r = radiusnew(s);
924 if (r)
925 {
926 radiussend(r, RADIUSSTART); // send radius start
927
928 // don't send further Start records if IPCP is restarted
929 session[s].flags |= SESSION_STARTED;
930 cluster_send_session(s);
931 }
932 }
933
934 // start IPv6 if configured and still in passive state
935 if (session[s].ppp.ipv6cp == Stopped)
936 {
937 sendipv6cp(s, t);
938 change_state(s, ipv6cp, RequestSent);
939 }
940 }
941
942 // Process IPCP messages
943 void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
944 {
945 uint8_t b[MAXETHER];
946 uint8_t *q = 0;
947 uint16_t hl;
948
949 CSTAT(processipcp);
950
951 LOG_HEX(5, "IPCP", p, l);
952 if (l < 5)
953 {
954 LOG(1, s, t, "Short IPCP %d bytes\n", l);
955 STAT(tunnel_rx_errors);
956 return ;
957 }
958
959 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
960 {
961 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
962 STAT(tunnel_rx_errors);
963 return ;
964 }
965 l = hl;
966
967 if (session[s].ppp.phase < Network)
968 {
969 LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
970 return;
971 }
972
973 LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
974
975 if (*p == ConfigAck)
976 {
977 switch (session[s].ppp.ipcp)
978 {
979 case RequestSent:
980 initialise_restart_count(s, ipcp);
981 change_state(s, ipcp, AckReceived);
982 break;
983
984 case AckReceived:
985 case Opened:
986 LOG(2, s, t, "IPCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
987 sendipcp(s, t);
988 change_state(s, ipcp, RequestSent);
989 break;
990
991 case AckSent:
992 ipcp_open(s, t);
993 break;
994
995 default:
996 LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
997 }
998 }
999 else if (*p == ConfigReq)
1000 {
1001 uint8_t *response = 0;
1002 uint8_t *o = p + 4;
1003 int length = l - 4;
1004 int gotip = 0;
1005 in_addr_t addr;
1006
1007 while (length > 2)
1008 {
1009 switch (*o)
1010 {
1011 case 3: // ip address
1012 gotip++; // seen address
1013 if (o[1] != 6 || o[1] > length) return;
1014
1015 addr = htonl(session[s].ip);
1016 if (memcmp(o + 2, &addr, (sizeof addr)))
1017 {
1018 uint8_t *oq = q;
1019 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1020 if (!q || (q != oq && *response == ConfigRej))
1021 {
1022 sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
1023 return;
1024 }
1025 }
1026
1027 break;
1028
1029 case 129: // primary DNS
1030 if (o[1] != 6 || o[1] > length) return;
1031
1032 addr = htonl(session[s].dns1);
1033 if (memcmp(o + 2, &addr, (sizeof addr)))
1034 {
1035 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1036 if (!q) return;
1037 }
1038
1039 break;
1040
1041 case 131: // secondary DNS
1042 if (o[1] != 6 || o[1] > length) return;
1043
1044 addr = htonl(session[s].dns2);
1045 if (memcmp(o + 2, &addr, sizeof(addr)))
1046 {
1047 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1048 if (!q) return;
1049 }
1050
1051 break;
1052
1053 default:
1054 LOG(2, s, t, " Rejecting PPP IPCP Option type %d\n", *o);
1055 q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
1056 if (!q) return;
1057 }
1058
1059 length -= o[1];
1060 o += o[1];
1061 }
1062
1063 if (response)
1064 {
1065 l = q - response; // IPCP packet length
1066 *((uint16_t *) (response + 2)) = htons(l); // update header
1067 }
1068 else if (gotip)
1069 {
1070 // Send packet back as ConfigAck
1071 response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1072 if (!response) return;
1073 *response = ConfigAck;
1074 }
1075 else
1076 {
1077 LOG(1, s, t, "No IP in IPCP request\n");
1078 STAT(tunnel_rx_errors);
1079 return;
1080 }
1081
1082 switch (session[s].ppp.ipcp)
1083 {
1084 case Closed:
1085 response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
1086 if (!response) return;
1087 *response = TerminateAck;
1088 *((uint16_t *) (response + 2)) = htons(l = 4);
1089 break;
1090
1091 case Stopped:
1092 initialise_restart_count(s, ipcp);
1093 sendipcp(s, t);
1094 if (*response == ConfigAck)
1095 change_state(s, ipcp, AckSent);
1096 else
1097 change_state(s, ipcp, RequestSent);
1098
1099 break;
1100
1101 case RequestSent:
1102 if (*response == ConfigAck)
1103 change_state(s, ipcp, AckSent);
1104
1105 break;
1106
1107 case AckReceived:
1108 if (*response == ConfigAck)
1109 ipcp_open(s, t);
1110
1111 break;
1112
1113 case Opened:
1114 initialise_restart_count(s, ipcp);
1115 sendipcp(s, t);
1116 /* fallthrough */
1117
1118 case AckSent:
1119 if (*response == ConfigAck)
1120 change_state(s, ipcp, AckSent);
1121 else
1122 change_state(s, ipcp, RequestSent);
1123
1124 break;
1125
1126 default:
1127 LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1128 return;
1129 }
1130
1131 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
1132 tunnelsend(b, l + (response - b), t);
1133 }
1134 else if (*p == TerminateReq)
1135 {
1136 *p = TerminateAck;
1137 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1138 if (!q) return;
1139 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
1140 tunnelsend(b, l + (q - b), t);
1141 change_state(s, ipcp, Stopped);
1142 }
1143 else if (*p != CodeRej)
1144 {
1145 ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
1146 }
1147 }
1148
1149 static void ipv6cp_open(sessionidt s, tunnelidt t)
1150 {
1151 LOG(3, s, t, "IPV6CP: Opened\n");
1152
1153 change_state(s, ipv6cp, Opened);
1154 if (session[s].ipv6prefixlen)
1155 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
1156
1157 // Send an initial RA (TODO: Should we send these regularly?)
1158 send_ipv6_ra(s, t, NULL);
1159 }
1160
1161 // Process IPV6CP messages
1162 void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1163 {
1164 uint8_t b[MAXETHER];
1165 uint8_t *q = 0;
1166 uint16_t hl;
1167
1168 CSTAT(processipv6cp);
1169
1170 LOG_HEX(5, "IPV6CP", p, l);
1171 if (l < 4)
1172 {
1173 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
1174 STAT(tunnel_rx_errors);
1175 return ;
1176 }
1177
1178 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
1179 {
1180 LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
1181 STAT(tunnel_rx_errors);
1182 return ;
1183 }
1184 l = hl;
1185
1186 if (session[s].ppp.phase < Network)
1187 {
1188 LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1189 return;
1190 }
1191
1192 LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
1193
1194 if (!session[s].ip)
1195 {
1196 LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
1197 return; // need IPCP to complete...
1198 }
1199
1200 if (*p == ConfigAck)
1201 {
1202 switch (session[s].ppp.ipv6cp)
1203 {
1204 case RequestSent:
1205 initialise_restart_count(s, ipv6cp);
1206 change_state(s, ipv6cp, AckReceived);
1207 break;
1208
1209 case AckReceived:
1210 case Opened:
1211 LOG(2, s, t, "IPV6CP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
1212 sendipv6cp(s, t);
1213 change_state(s, ipv6cp, RequestSent);
1214 break;
1215
1216 case AckSent:
1217 ipv6cp_open(s, t);
1218 break;
1219
1220 default:
1221 LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1222 }
1223 }
1224 else if (*p == ConfigReq)
1225 {
1226 uint8_t *response = 0;
1227 uint8_t *o = p + 4;
1228 int length = l - 4;
1229 int gotip = 0;
1230 uint8_t ident[8];
1231
1232 while (length > 2)
1233 {
1234 switch (*o)
1235 {
1236 case 1: // interface identifier
1237 gotip++; // seen address
1238 if (o[1] != 10 || o[1] > length) return;
1239
1240 *(uint32_t *) ident = htonl(session[s].ip);
1241 *(uint32_t *) (ident + 4) = 0;
1242
1243 if (memcmp(o + 2, ident, sizeof(ident)))
1244 {
1245 q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
1246 if (!q) return;
1247 }
1248
1249 break;
1250
1251 default:
1252 LOG(2, s, t, " Rejecting PPP IPV6CP Option type %d\n", *o);
1253 q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
1254 if (!q) return;
1255 }
1256
1257 length -= o[1];
1258 o += o[1];
1259 }
1260
1261 if (response)
1262 {
1263 l = q - response; // IPV6CP packet length
1264 *((uint16_t *) (response + 2)) = htons(l); // update header
1265 }
1266 else if (gotip)
1267 {
1268 // Send packet back as ConfigAck
1269 response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1270 if (!response) return;
1271 *response = ConfigAck;
1272 }
1273 else
1274 {
1275 LOG(1, s, t, "No interface identifier in IPV6CP request\n");
1276 STAT(tunnel_rx_errors);
1277 return;
1278 }
1279
1280 switch (session[s].ppp.ipv6cp)
1281 {
1282 case Closed:
1283 response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
1284 if (!response) return;
1285 *response = TerminateAck;
1286 *((uint16_t *) (response + 2)) = htons(l = 4);
1287 break;
1288
1289 case Stopped:
1290 initialise_restart_count(s, ipv6cp);
1291 sendipv6cp(s, t);
1292 if (*response == ConfigAck)
1293 change_state(s, ipv6cp, AckSent);
1294 else
1295 change_state(s, ipv6cp, RequestSent);
1296
1297 break;
1298
1299 case RequestSent:
1300 if (*response == ConfigAck)
1301 change_state(s, ipv6cp, AckSent);
1302
1303 break;
1304
1305 case AckReceived:
1306 if (*response == ConfigAck)
1307 ipv6cp_open(s, t);
1308
1309 break;
1310
1311 case Opened:
1312 initialise_restart_count(s, ipv6cp);
1313 sendipv6cp(s, t);
1314 /* fallthrough */
1315
1316 case AckSent:
1317 if (*response == ConfigAck)
1318 change_state(s, ipv6cp, AckSent);
1319 else
1320 change_state(s, ipv6cp, RequestSent);
1321
1322 break;
1323
1324 default:
1325 LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1326 return;
1327 }
1328
1329 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
1330 tunnelsend(b, l + (response - b), t);
1331 }
1332 else if (*p == TerminateReq)
1333 {
1334 *p = TerminateAck;
1335 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1336 if (!q) return;
1337 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
1338 tunnelsend(b, l + (q - b), t);
1339 change_state(s, ipv6cp, Stopped);
1340 }
1341 else if (*p != CodeRej)
1342 {
1343 ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
1344 }
1345 }
1346
1347 // process IP packet received
1348 //
1349 // This MUST be called with at least 4 byte behind 'p'.
1350 // (i.e. this routine writes to p[-4]).
1351 void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1352 {
1353 in_addr_t ip;
1354
1355 CSTAT(processipin);
1356
1357 LOG_HEX(5, "IP", p, l);
1358
1359 if (l < 20)
1360 {
1361 LOG(1, s, t, "IP packet too short %d\n", l);
1362 STAT(tunnel_rx_errors);
1363 return ;
1364 }
1365
1366 ip = ntohl(*(uint32_t *)(p + 12));
1367
1368 if (l > MAXETHER)
1369 {
1370 LOG(1, s, t, "IP packet too long %d\n", l);
1371 STAT(tunnel_rx_errors);
1372 return ;
1373 }
1374
1375 if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
1376 return;
1377
1378 // no spoof (do sessionbyip to handled statically routed subnets)
1379 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
1380 {
1381 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
1382 return;
1383 }
1384
1385 // run access-list if any
1386 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
1387 return;
1388
1389 // adjust MSS on SYN and SYN,ACK packets with options
1390 if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
1391 {
1392 int ihl = (p[0] & 0xf) * 4; // length of IP header
1393 if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
1394 adjust_tcp_mss(s, t, p, l, p + ihl);
1395 }
1396
1397 // Add on the tun header
1398 p -= 4;
1399 *(uint32_t *) p = htonl(PKTIP);
1400 l += 4;
1401
1402 // Are we throttled and a slave?
1403 if (session[s].tbf_in && !config->cluster_iam_master) {
1404 // Pass it to the master for handling.
1405 master_throttle_packet(session[s].tbf_in, p, l);
1406 return;
1407 }
1408
1409 // Are we throttled and a master??
1410 if (session[s].tbf_in && config->cluster_iam_master) {
1411 // Actually handle the throttled packets.
1412 tbf_queue_packet(session[s].tbf_in, p, l);
1413 return;
1414 }
1415
1416 // send to ethernet
1417 if (tun_write(p, l) < 0)
1418 {
1419 STAT(tun_tx_errors);
1420 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1421 l, strerror(errno), tunfd, p);
1422
1423 return;
1424 }
1425
1426 p += 4;
1427 l -= 4;
1428
1429 if (session[s].snoop_ip && session[s].snoop_port)
1430 {
1431 // Snooping this session
1432 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1433 }
1434
1435 increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1436 session[s].cin_delta += l;
1437 session[s].pin++;
1438
1439 sess_local[s].cin += l;
1440 sess_local[s].pin++;
1441
1442 eth_tx += l;
1443
1444 STAT(tun_tx_packets);
1445 INC_STAT(tun_tx_bytes, l);
1446 }
1447
1448 // process IPv6 packet received
1449 //
1450 // This MUST be called with at least 4 byte behind 'p'.
1451 // (i.e. this routine writes to p[-4]).
1452 void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1453 {
1454 struct in6_addr ip;
1455 in_addr_t ipv4;
1456
1457 CSTAT(processipv6in);
1458
1459 LOG_HEX(5, "IPv6", p, l);
1460
1461 ip = *(struct in6_addr *) (p + 8);
1462 ipv4 = ntohl(*(uint32_t *)(p + 16));
1463
1464 if (l > MAXETHER)
1465 {
1466 LOG(1, s, t, "IP packet too long %d\n", l);
1467 STAT(tunnel_rx_errors);
1468 return ;
1469 }
1470
1471 if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
1472 return;
1473
1474 // no spoof
1475 if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1476 {
1477 char str[INET6_ADDRSTRLEN];
1478 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1479 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1480 return;
1481 }
1482
1483 // Check if it's a Router Solicition message.
1484 if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1485 *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1486 *(uint32_t *)(p + 34) == 0 &&
1487 *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1488 LOG(3, s, t, "Got IPv6 RS\n");
1489 send_ipv6_ra(s, t, &ip);
1490 return;
1491 }
1492
1493 // Add on the tun header
1494 p -= 4;
1495 *(uint32_t *) p = htonl(PKTIPV6);
1496 l += 4;
1497
1498 // Are we throttled and a slave?
1499 if (session[s].tbf_in && !config->cluster_iam_master) {
1500 // Pass it to the master for handling.
1501 master_throttle_packet(session[s].tbf_in, p, l);
1502 return;
1503 }
1504
1505 // Are we throttled and a master??
1506 if (session[s].tbf_in && config->cluster_iam_master) {
1507 // Actually handle the throttled packets.
1508 tbf_queue_packet(session[s].tbf_in, p, l);
1509 return;
1510 }
1511
1512 // send to ethernet
1513 if (tun_write(p, l) < 0)
1514 {
1515 STAT(tun_tx_errors);
1516 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1517 l, strerror(errno), tunfd, p);
1518
1519 return;
1520 }
1521
1522 p += 4;
1523 l -= 4;
1524
1525 if (session[s].snoop_ip && session[s].snoop_port)
1526 {
1527 // Snooping this session
1528 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1529 }
1530
1531 increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1532 session[s].cin_delta += l;
1533 session[s].pin++;
1534
1535 sess_local[s].cin += l;
1536 sess_local[s].pin++;
1537
1538 eth_tx += l;
1539
1540 STAT(tun_tx_packets);
1541 INC_STAT(tun_tx_bytes, l);
1542 }
1543
1544 //
1545 // Helper routine for the TBF filters.
1546 // Used to send queued data in from the user.
1547 //
1548 void send_ipin(sessionidt s, uint8_t *buf, int len)
1549 {
1550 LOG_HEX(5, "IP in throttled", buf, len);
1551
1552 if (write(tunfd, buf, len) < 0)
1553 {
1554 STAT(tun_tx_errors);
1555 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1556 len, strerror(errno), tunfd, buf);
1557
1558 return;
1559 }
1560
1561 buf += 4;
1562 len -= 4;
1563
1564 if (session[s].snoop_ip && session[s].snoop_port)
1565 {
1566 // Snooping this session
1567 snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
1568 }
1569
1570 // Increment packet counters
1571 increment_counter(&session[s].cin, &session[s].cin_wrap, len);
1572 session[s].cin_delta += len;
1573 session[s].pin++;
1574
1575 sess_local[s].cin += len;
1576 sess_local[s].pin++;
1577
1578 eth_tx += len;
1579
1580 STAT(tun_tx_packets);
1581 INC_STAT(tun_tx_bytes, len - 4);
1582 }
1583
1584
1585 // Process CCP messages
1586 void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1587 {
1588 uint8_t b[MAXETHER];
1589 uint8_t *q;
1590
1591 CSTAT(processccp);
1592
1593 LOG_HEX(5, "CCP", p, l);
1594
1595 if (session[s].ppp.phase < Network)
1596 {
1597 LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1598 return;
1599 }
1600
1601 if (l < 1)
1602 {
1603 LOG(1, s, t, "Short CCP packet\n");
1604 STAT(tunnel_rx_errors);
1605 }
1606
1607 LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
1608 if (*p == ConfigAck)
1609 {
1610 switch (session[s].ppp.ccp)
1611 {
1612 case RequestSent:
1613 initialise_restart_count(s, ccp);
1614 change_state(s, ccp, AckReceived);
1615 break;
1616
1617 case AckReceived:
1618 case Opened:
1619 LOG(2, s, t, "CCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
1620 sendccp(s, t);
1621 change_state(s, ccp, RequestSent);
1622 break;
1623
1624 case AckSent:
1625 LOG(3, s, t, "CCP: Opened\n");
1626 change_state(s, ccp, Opened);
1627 break;
1628
1629 default:
1630 LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1631 }
1632 }
1633 else if (*p == ConfigReq)
1634 {
1635 if (l < 6) // accept no compression
1636 *p = ConfigAck;
1637 else // compression requested--reject
1638 *p = ConfigRej;
1639
1640 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1641 if (!q) return;
1642
1643 switch (session[s].ppp.ccp)
1644 {
1645 case Closed:
1646 q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
1647 if (!q) return;
1648 *q = TerminateAck;
1649 *((uint16_t *) (q + 2)) = htons(l = 4);
1650 break;
1651
1652 case Stopped:
1653 initialise_restart_count(s, ccp);
1654 sendccp(s, t);
1655 if (*q == ConfigAck)
1656 change_state(s, ccp, AckSent);
1657 else
1658 change_state(s, ccp, RequestSent);
1659
1660 break;
1661
1662 case RequestSent:
1663 if (*q == ConfigAck)
1664 change_state(s, ccp, AckSent);
1665
1666 break;
1667
1668 case AckReceived:
1669 if (*q == ConfigAck)
1670 change_state(s, ccp, Opened);
1671
1672 break;
1673
1674 case Opened:
1675 initialise_restart_count(s, ccp);
1676 sendccp(s, t);
1677 /* fallthrough */
1678
1679 case AckSent:
1680 if (*q == ConfigAck)
1681 change_state(s, ccp, AckSent);
1682 else
1683 change_state(s, ccp, RequestSent);
1684
1685 break;
1686
1687 default:
1688 LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1689 return;
1690 }
1691
1692 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1693 tunnelsend(b, l + (q - b), t);
1694 }
1695 else if (*p == TerminateReq)
1696 {
1697 *p = TerminateAck;
1698 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1699 if (!q) return;
1700 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1701 tunnelsend(b, l + (q - b), t);
1702 change_state(s, ccp, Stopped);
1703 }
1704 else if (*p != CodeRej)
1705 {
1706 ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
1707 }
1708 }
1709
1710 // send a CHAP challenge
1711 void sendchap(sessionidt s, tunnelidt t)
1712 {
1713 uint8_t b[MAXETHER];
1714 uint16_t r;
1715 uint8_t *q;
1716
1717 CSTAT(sendchap);
1718
1719 r = radiusnew(s);
1720 if (!r)
1721 {
1722 LOG(1, s, t, "No RADIUS to send challenge\n");
1723 STAT(tunnel_tx_errors);
1724 return;
1725 }
1726
1727 LOG(1, s, t, "Send CHAP challenge\n");
1728
1729 radius[r].chap = 1; // CHAP not PAP
1730 radius[r].id++;
1731 if (radius[r].state != RADIUSCHAP)
1732 radius[r].try = 0;
1733
1734 radius[r].state = RADIUSCHAP;
1735 radius[r].retry = backoff(radius[r].try++);
1736 if (radius[r].try > 5)
1737 {
1738 sessionshutdown(s, "CHAP timeout.", 3, 0);
1739 STAT(tunnel_tx_errors);
1740 return ;
1741 }
1742 q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
1743 if (!q) return;
1744
1745 *q = 1; // challenge
1746 q[1] = radius[r].id; // ID
1747 q[4] = 16; // value size (size of challenge)
1748 memcpy(q + 5, radius[r].auth, 16); // challenge
1749 strcpy((char *) q + 21, hostname); // our name
1750 *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1751 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1752 }
1753
1754 // fill in a L2TP message with a PPP frame,
1755 // copies existing PPP message and changes magic number if seen
1756 // returns start of PPP frame
1757 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
1758 {
1759 if (size < 12) // Need more space than this!!
1760 {
1761 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1762 return NULL;
1763 }
1764
1765 *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1766 *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1767 *(uint16_t *) (b + 4) = htons(session[s].far); // session
1768 b += 6;
1769 if (mtype == PPPLCP || !(session[s].flags & SESSION_ACFC))
1770 {
1771 *(uint16_t *) b = htons(0xFF03); // HDLC header
1772 b += 2;
1773 }
1774 if (mtype < 0x100 && session[s].flags & SESSION_PFC)
1775 *b++ = mtype;
1776 else
1777 {
1778 *(uint16_t *) b = htons(mtype);
1779 b += 2;
1780 }
1781
1782 if (l + 12 > size)
1783 {
1784 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1785 return NULL;
1786 }
1787
1788 if (p && l)
1789 memcpy(b, p, l);
1790
1791 return b;
1792 }
1793
1794 static int add_lcp_auth(uint8_t *b, int size, int authtype)
1795 {
1796 int len = 0;
1797 if ((authtype == AUTHCHAP && size < 5) || size < 4)
1798 return 0;
1799
1800 *b++ = 3; // Authentication-Protocol
1801 if (authtype == AUTHCHAP)
1802 {
1803 len = *b++ = 5; // length
1804 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1805 *b++ = 5; // MD5
1806 }
1807 else if (authtype == AUTHPAP)
1808 {
1809 len = *b++ = 4; // length
1810 *(uint16_t *) b = htons(PPPPAP); b += 2;
1811 }
1812 else
1813 {
1814 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1815 }
1816
1817 return len;
1818 }
1819
1820 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1821 void sendlcp(sessionidt s, tunnelidt t)
1822 {
1823 uint8_t b[500], *q, *l;
1824 int authtype = sess_local[s].lcp_authtype;
1825
1826 if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
1827 return;
1828
1829 LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
1830 authtype ? " (" : "",
1831 authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
1832 authtype ? ")" : "");
1833
1834 l = q;
1835 *l++ = ConfigReq;
1836 *l++ = ++sess_local[s].lcp_ident; // ID
1837
1838 l += 2; //Save space for length
1839
1840 if (sess_local[s].ppp_mru)
1841 {
1842 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1843 *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
1844 }
1845
1846 if (authtype)
1847 l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1848
1849 *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1850 *(uint32_t *) l = htonl(session[s].magic);
1851 l += 4;
1852
1853 *(uint16_t *)(q + 2) = htons(l - q); // Length
1854
1855 LOG_HEX(5, "PPPLCP", q, l - q);
1856 if (config->debug > 3) dumplcp(q, l - q);
1857
1858 tunnelsend(b, (l - b), t);
1859 restart_timer(s, lcp);
1860 }
1861
1862 // Send CCP request for no compression
1863 void sendccp(sessionidt s, tunnelidt t)
1864 {
1865 uint8_t b[500], *q;
1866
1867 if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
1868 return;
1869
1870 LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
1871
1872 *q = ConfigReq;
1873 *(q + 1) = ++sess_local[s].lcp_ident; // ID
1874 *(uint16_t *)(q + 2) = htons(4); // Length
1875
1876 LOG_HEX(5, "PPPCCP", q, 4);
1877 tunnelsend(b, (q - b) + 4 , t);
1878 restart_timer(s, ccp);
1879 }
1880
1881 // Reject unknown/unconfigured protocols
1882 void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
1883 {
1884
1885 uint8_t buf[MAXETHER];
1886 uint8_t *q;
1887 int mru = session[s].mru;
1888 if (mru < MINMTU) mru = MINMTU;
1889 if (mru > sizeof(buf)) mru = sizeof(buf);
1890
1891 l += 6;
1892 if (l > mru) l = mru;
1893
1894 q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
1895 if (!q) return;
1896
1897 *q = ProtocolRej;
1898 *(q + 1) = ++sess_local[s].lcp_ident;
1899 *(uint16_t *)(q + 2) = htons(l);
1900 *(uint16_t *)(q + 4) = htons(proto);
1901 memcpy(q + 6, p, l - 6);
1902
1903 if (proto == PPPIPV6CP)
1904 LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
1905 else
1906 LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
1907
1908 tunnelsend(buf, l + (q - buf), t);
1909 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"