projects / l2tpns.git / blob
? search:


349f388f45655a01f710b528aae7a0eb2299ec7f
[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.90 2005/12/15 14:18:16 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 break;
800 }
801 x -= length;
802 o += length;
803 }
804
805 if (!authtype)
806 {
807 sessionshutdown(s, "Unsupported authentication.", 3, 0);
808 return;
809 }
810
811 if (authtype > 0)
812 sess_local[s].lcp_authtype = authtype;
813
814 switch (session[s].ppp.lcp)
815 {
816 case Closed:
817 case Stopped:
818 {
819 uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
820 if (!response) return;
821 *response = TerminateAck;
822 *((uint16_t *) (response + 2)) = htons(l = 4);
823
824 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
825 if (config->debug > 3) dumplcp(response, l);
826
827 tunnelsend(b, l + (response - b), t);
828 }
829 break;
830
831 case RequestSent:
832 case AckSent:
833 initialise_restart_count(s, lcp);
834 sendlcp(s, t);
835 break;
836
837 case AckReceived:
838 LOG(2, s, t, "LCP: ConfigNak in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
839 sendlcp(s, t);
840 break;
841
842 case Opened:
843 lcp_restart(s);
844 sendlcp(s, t);
845 break;
846
847 default:
848 LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
849 return;
850 }
851 }
852 else if (*p == TerminateReq)
853 {
854 *p = TerminateAck; // close
855 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
856 if (!q) return;
857
858 LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
859 if (config->debug > 3) dumplcp(q, l);
860
861 tunnelsend(b, l + (q - b), t); // send it
862 sessionshutdown(s, "Remote end closed connection.", 3, 0);
863 }
864 else if (*p == TerminateAck)
865 {
866 sessionshutdown(s, "Connection closed.", 3, 0);
867 }
868 else if (*p == ProtocolRej)
869 {
870 uint16_t proto = 0;
871
872 if (l > 4)
873 {
874 proto = *(p+4);
875 if (l > 5 && !(proto & 1))
876 {
877 proto <<= 8;
878 proto |= *(p+5);
879 }
880 }
881
882 if (proto == PPPIPV6CP)
883 {
884 LOG(3, s, t, "IPv6 rejected\n");
885 change_state(s, ipv6cp, Closed);
886 }
887 else
888 {
889 LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
890 }
891 }
892 else if (*p == EchoReq)
893 {
894 *p = EchoReply; // reply
895 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
896 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
897 if (!q) return;
898
899 LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
900 if (config->debug > 3) dumplcp(q, l);
901
902 tunnelsend(b, l + (q - b), t); // send it
903 }
904 else if (*p == EchoReply)
905 {
906 // Ignore it, last_packet time is set earlier than this.
907 }
908 else if (*p != CodeRej)
909 {
910 ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
911 }
912 }
913
914 static void ipcp_open(sessionidt s, tunnelidt t)
915 {
916 LOG(3, s, t, "IPCP: Opened, session is now active\n");
917
918 change_state(s, ipcp, Opened);
919
920 if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
921 {
922 uint16_t r = radiusnew(s);
923 if (r)
924 {
925 radiussend(r, RADIUSSTART); // send radius start
926
927 // don't send further Start records if IPCP is restarted
928 session[s].flags |= SESSION_STARTED;
929 cluster_send_session(s);
930 }
931 }
932
933 // start IPv6 if configured and still in passive state
934 if (session[s].ppp.ipv6cp == Stopped)
935 {
936 sendipv6cp(s, t);
937 change_state(s, ipv6cp, RequestSent);
938 }
939 }
940
941 // Process IPCP messages
942 void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
943 {
944 uint8_t b[MAXETHER];
945 uint8_t *q = 0;
946 uint16_t hl;
947
948 CSTAT(processipcp);
949
950 LOG_HEX(5, "IPCP", p, l);
951 if (l < 5)
952 {
953 LOG(1, s, t, "Short IPCP %d bytes\n", l);
954 STAT(tunnel_rx_errors);
955 return ;
956 }
957
958 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
959 {
960 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
961 STAT(tunnel_rx_errors);
962 return ;
963 }
964 l = hl;
965
966 if (session[s].ppp.phase < Network)
967 {
968 LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
969 return;
970 }
971
972 LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
973
974 if (*p == ConfigAck)
975 {
976 switch (session[s].ppp.ipcp)
977 {
978 case RequestSent:
979 initialise_restart_count(s, ipcp);
980 change_state(s, ipcp, AckReceived);
981 break;
982
983 case AckReceived:
984 case Opened:
985 LOG(2, s, t, "IPCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
986 sendipcp(s, t);
987 change_state(s, ipcp, RequestSent);
988 break;
989
990 case AckSent:
991 ipcp_open(s, t);
992 break;
993
994 default:
995 LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
996 }
997 }
998 else if (*p == ConfigReq)
999 {
1000 uint8_t *response = 0;
1001 uint8_t *o = p + 4;
1002 int length = l - 4;
1003 int gotip = 0;
1004 in_addr_t addr;
1005
1006 while (length > 2)
1007 {
1008 switch (*o)
1009 {
1010 case 3: // ip address
1011 gotip++; // seen address
1012 if (o[1] != 6 || o[1] > length) return;
1013
1014 addr = htonl(session[s].ip);
1015 if (memcmp(o + 2, &addr, (sizeof addr)))
1016 {
1017 uint8_t *oq = q;
1018 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1019 if (!q || (q != oq && *response == ConfigRej))
1020 {
1021 sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
1022 return;
1023 }
1024 }
1025
1026 break;
1027
1028 case 129: // primary DNS
1029 if (o[1] != 6 || o[1] > length) return;
1030
1031 addr = htonl(session[s].dns1);
1032 if (memcmp(o + 2, &addr, (sizeof addr)))
1033 {
1034 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1035 if (!q) return;
1036 }
1037
1038 break;
1039
1040 case 131: // secondary DNS
1041 if (o[1] != 6 || o[1] > length) return;
1042
1043 addr = htonl(session[s].dns2);
1044 if (memcmp(o + 2, &addr, sizeof(addr)))
1045 {
1046 q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1047 if (!q) return;
1048 }
1049
1050 break;
1051
1052 default:
1053 LOG(2, s, t, " Rejecting PPP IPCP Option type %d\n", *o);
1054 q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
1055 if (!q) return;
1056 }
1057
1058 length -= o[1];
1059 o += o[1];
1060 }
1061
1062 if (response)
1063 {
1064 l = q - response; // IPCP packet length
1065 *((uint16_t *) (response + 2)) = htons(l); // update header
1066 }
1067 else if (gotip)
1068 {
1069 // Send packet back as ConfigAck
1070 response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1071 if (!response) return;
1072 *response = ConfigAck;
1073 }
1074 else
1075 {
1076 LOG(1, s, t, "No IP in IPCP request\n");
1077 STAT(tunnel_rx_errors);
1078 return;
1079 }
1080
1081 switch (session[s].ppp.ipcp)
1082 {
1083 case Closed:
1084 response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
1085 if (!response) return;
1086 *response = TerminateAck;
1087 *((uint16_t *) (response + 2)) = htons(l = 4);
1088 break;
1089
1090 case Stopped:
1091 initialise_restart_count(s, ipcp);
1092 sendipcp(s, t);
1093 if (*response == ConfigAck)
1094 change_state(s, ipcp, AckSent);
1095 else
1096 change_state(s, ipcp, RequestSent);
1097
1098 break;
1099
1100 case RequestSent:
1101 if (*response == ConfigAck)
1102 change_state(s, ipcp, AckSent);
1103
1104 break;
1105
1106 case AckReceived:
1107 if (*response == ConfigAck)
1108 ipcp_open(s, t);
1109
1110 break;
1111
1112 case Opened:
1113 initialise_restart_count(s, ipcp);
1114 sendipcp(s, t);
1115 /* fallthrough */
1116
1117 case AckSent:
1118 if (*response == ConfigAck)
1119 change_state(s, ipcp, AckSent);
1120 else
1121 change_state(s, ipcp, RequestSent);
1122
1123 break;
1124
1125 default:
1126 LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1127 return;
1128 }
1129
1130 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
1131 tunnelsend(b, l + (response - b), t);
1132 }
1133 else if (*p == TerminateReq)
1134 {
1135 *p = TerminateAck;
1136 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1137 if (!q) return;
1138 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
1139 tunnelsend(b, l + (q - b), t);
1140 change_state(s, ipcp, Stopped);
1141 }
1142 else if (*p != CodeRej)
1143 {
1144 ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
1145 }
1146 }
1147
1148 static void ipv6cp_open(sessionidt s, tunnelidt t)
1149 {
1150 LOG(3, s, t, "IPV6CP: Opened\n");
1151
1152 change_state(s, ipv6cp, Opened);
1153 if (session[s].ipv6prefixlen)
1154 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
1155
1156 // Send an initial RA (TODO: Should we send these regularly?)
1157 send_ipv6_ra(s, t, NULL);
1158 }
1159
1160 // Process IPV6CP messages
1161 void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1162 {
1163 uint8_t b[MAXETHER];
1164 uint8_t *q = 0;
1165 uint16_t hl;
1166
1167 CSTAT(processipv6cp);
1168
1169 LOG_HEX(5, "IPV6CP", p, l);
1170 if (l < 4)
1171 {
1172 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
1173 STAT(tunnel_rx_errors);
1174 return ;
1175 }
1176
1177 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
1178 {
1179 LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
1180 STAT(tunnel_rx_errors);
1181 return ;
1182 }
1183 l = hl;
1184
1185 if (session[s].ppp.phase < Network)
1186 {
1187 LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1188 return;
1189 }
1190
1191 LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
1192
1193 if (!session[s].ip)
1194 {
1195 LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
1196 return; // need IPCP to complete...
1197 }
1198
1199 if (*p == ConfigAck)
1200 {
1201 switch (session[s].ppp.ipv6cp)
1202 {
1203 case RequestSent:
1204 initialise_restart_count(s, ipv6cp);
1205 change_state(s, ipv6cp, AckReceived);
1206 break;
1207
1208 case AckReceived:
1209 case Opened:
1210 LOG(2, s, t, "IPV6CP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
1211 sendipv6cp(s, t);
1212 change_state(s, ipv6cp, RequestSent);
1213 break;
1214
1215 case AckSent:
1216 ipv6cp_open(s, t);
1217 break;
1218
1219 default:
1220 LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1221 }
1222 }
1223 else if (*p == ConfigReq)
1224 {
1225 uint8_t *response = 0;
1226 uint8_t *o = p + 4;
1227 int length = l - 4;
1228 int gotip = 0;
1229 uint8_t ident[8];
1230
1231 while (length > 2)
1232 {
1233 switch (*o)
1234 {
1235 case 1: // interface identifier
1236 gotip++; // seen address
1237 if (o[1] != 10 || o[1] > length) return;
1238
1239 *(uint32_t *) ident = htonl(session[s].ip);
1240 *(uint32_t *) (ident + 4) = 0;
1241
1242 if (memcmp(o + 2, ident, sizeof(ident)))
1243 {
1244 q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
1245 if (!q) return;
1246 }
1247
1248 break;
1249
1250 default:
1251 LOG(2, s, t, " Rejecting PPP IPV6CP Option type %d\n", *o);
1252 q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
1253 if (!q) return;
1254 }
1255
1256 length -= o[1];
1257 o += o[1];
1258 }
1259
1260 if (response)
1261 {
1262 l = q - response; // IPV6CP packet length
1263 *((uint16_t *) (response + 2)) = htons(l); // update header
1264 }
1265 else if (gotip)
1266 {
1267 // Send packet back as ConfigAck
1268 response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1269 if (!response) return;
1270 *response = ConfigAck;
1271 }
1272 else
1273 {
1274 LOG(1, s, t, "No interface identifier in IPV6CP request\n");
1275 STAT(tunnel_rx_errors);
1276 return;
1277 }
1278
1279 switch (session[s].ppp.ipv6cp)
1280 {
1281 case Closed:
1282 response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
1283 if (!response) return;
1284 *response = TerminateAck;
1285 *((uint16_t *) (response + 2)) = htons(l = 4);
1286 break;
1287
1288 case Stopped:
1289 initialise_restart_count(s, ipv6cp);
1290 sendipv6cp(s, t);
1291 if (*response == ConfigAck)
1292 change_state(s, ipv6cp, AckSent);
1293 else
1294 change_state(s, ipv6cp, RequestSent);
1295
1296 break;
1297
1298 case RequestSent:
1299 if (*response == ConfigAck)
1300 change_state(s, ipv6cp, AckSent);
1301
1302 break;
1303
1304 case AckReceived:
1305 if (*response == ConfigAck)
1306 ipv6cp_open(s, t);
1307
1308 break;
1309
1310 case Opened:
1311 initialise_restart_count(s, ipv6cp);
1312 sendipv6cp(s, t);
1313 /* fallthrough */
1314
1315 case AckSent:
1316 if (*response == ConfigAck)
1317 change_state(s, ipv6cp, AckSent);
1318 else
1319 change_state(s, ipv6cp, RequestSent);
1320
1321 break;
1322
1323 default:
1324 LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1325 return;
1326 }
1327
1328 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
1329 tunnelsend(b, l + (response - b), t);
1330 }
1331 else if (*p == TerminateReq)
1332 {
1333 *p = TerminateAck;
1334 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1335 if (!q) return;
1336 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
1337 tunnelsend(b, l + (q - b), t);
1338 change_state(s, ipv6cp, Stopped);
1339 }
1340 else if (*p != CodeRej)
1341 {
1342 ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
1343 }
1344 }
1345
1346 // process IP packet received
1347 //
1348 // This MUST be called with at least 4 byte behind 'p'.
1349 // (i.e. this routine writes to p[-4]).
1350 void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1351 {
1352 in_addr_t ip;
1353
1354 CSTAT(processipin);
1355
1356 LOG_HEX(5, "IP", p, l);
1357
1358 if (l < 20)
1359 {
1360 LOG(1, s, t, "IP packet too short %d\n", l);
1361 STAT(tunnel_rx_errors);
1362 return ;
1363 }
1364
1365 ip = ntohl(*(uint32_t *)(p + 12));
1366
1367 if (l > MAXETHER)
1368 {
1369 LOG(1, s, t, "IP packet too long %d\n", l);
1370 STAT(tunnel_rx_errors);
1371 return ;
1372 }
1373
1374 if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
1375 return;
1376
1377 // no spoof (do sessionbyip to handled statically routed subnets)
1378 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
1379 {
1380 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
1381 return;
1382 }
1383
1384 // run access-list if any
1385 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
1386 return;
1387
1388 // adjust MSS on SYN and SYN,ACK packets with options
1389 if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
1390 {
1391 int ihl = (p[0] & 0xf) * 4; // length of IP header
1392 if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
1393 adjust_tcp_mss(s, t, p, l, p + ihl);
1394 }
1395
1396 // Add on the tun header
1397 p -= 4;
1398 *(uint32_t *) p = htonl(PKTIP);
1399 l += 4;
1400
1401 // Are we throttled and a slave?
1402 if (session[s].tbf_in && !config->cluster_iam_master) {
1403 // Pass it to the master for handling.
1404 master_throttle_packet(session[s].tbf_in, p, l);
1405 return;
1406 }
1407
1408 // Are we throttled and a master??
1409 if (session[s].tbf_in && config->cluster_iam_master) {
1410 // Actually handle the throttled packets.
1411 tbf_queue_packet(session[s].tbf_in, p, l);
1412 return;
1413 }
1414
1415 // send to ethernet
1416 if (tun_write(p, l) < 0)
1417 {
1418 STAT(tun_tx_errors);
1419 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1420 l, strerror(errno), tunfd, p);
1421
1422 return;
1423 }
1424
1425 p += 4;
1426 l -= 4;
1427
1428 if (session[s].snoop_ip && session[s].snoop_port)
1429 {
1430 // Snooping this session
1431 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1432 }
1433
1434 increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1435 session[s].cin_delta += l;
1436 session[s].pin++;
1437
1438 sess_local[s].cin += l;
1439 sess_local[s].pin++;
1440
1441 eth_tx += l;
1442
1443 STAT(tun_tx_packets);
1444 INC_STAT(tun_tx_bytes, l);
1445 }
1446
1447 // process IPv6 packet received
1448 //
1449 // This MUST be called with at least 4 byte behind 'p'.
1450 // (i.e. this routine writes to p[-4]).
1451 void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1452 {
1453 struct in6_addr ip;
1454 in_addr_t ipv4;
1455
1456 CSTAT(processipv6in);
1457
1458 LOG_HEX(5, "IPv6", p, l);
1459
1460 ip = *(struct in6_addr *) (p + 8);
1461 ipv4 = ntohl(*(uint32_t *)(p + 16));
1462
1463 if (l > MAXETHER)
1464 {
1465 LOG(1, s, t, "IP packet too long %d\n", l);
1466 STAT(tunnel_rx_errors);
1467 return ;
1468 }
1469
1470 if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
1471 return;
1472
1473 // no spoof
1474 if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1475 {
1476 char str[INET6_ADDRSTRLEN];
1477 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1478 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1479 return;
1480 }
1481
1482 // Check if it's a Router Solicition message.
1483 if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1484 *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1485 *(uint32_t *)(p + 34) == 0 &&
1486 *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1487 LOG(3, s, t, "Got IPv6 RS\n");
1488 send_ipv6_ra(s, t, &ip);
1489 return;
1490 }
1491
1492 // Add on the tun header
1493 p -= 4;
1494 *(uint32_t *) p = htonl(PKTIPV6);
1495 l += 4;
1496
1497 // Are we throttled and a slave?
1498 if (session[s].tbf_in && !config->cluster_iam_master) {
1499 // Pass it to the master for handling.
1500 master_throttle_packet(session[s].tbf_in, p, l);
1501 return;
1502 }
1503
1504 // Are we throttled and a master??
1505 if (session[s].tbf_in && config->cluster_iam_master) {
1506 // Actually handle the throttled packets.
1507 tbf_queue_packet(session[s].tbf_in, p, l);
1508 return;
1509 }
1510
1511 // send to ethernet
1512 if (tun_write(p, l) < 0)
1513 {
1514 STAT(tun_tx_errors);
1515 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1516 l, strerror(errno), tunfd, p);
1517
1518 return;
1519 }
1520
1521 p += 4;
1522 l -= 4;
1523
1524 if (session[s].snoop_ip && session[s].snoop_port)
1525 {
1526 // Snooping this session
1527 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1528 }
1529
1530 increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1531 session[s].cin_delta += l;
1532 session[s].pin++;
1533
1534 sess_local[s].cin += l;
1535 sess_local[s].pin++;
1536
1537 eth_tx += l;
1538
1539 STAT(tun_tx_packets);
1540 INC_STAT(tun_tx_bytes, l);
1541 }
1542
1543 //
1544 // Helper routine for the TBF filters.
1545 // Used to send queued data in from the user.
1546 //
1547 void send_ipin(sessionidt s, uint8_t *buf, int len)
1548 {
1549 LOG_HEX(5, "IP in throttled", buf, len);
1550
1551 if (write(tunfd, buf, len) < 0)
1552 {
1553 STAT(tun_tx_errors);
1554 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1555 len, strerror(errno), tunfd, buf);
1556
1557 return;
1558 }
1559
1560 buf += 4;
1561 len -= 4;
1562
1563 if (session[s].snoop_ip && session[s].snoop_port)
1564 {
1565 // Snooping this session
1566 snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
1567 }
1568
1569 // Increment packet counters
1570 increment_counter(&session[s].cin, &session[s].cin_wrap, len);
1571 session[s].cin_delta += len;
1572 session[s].pin++;
1573
1574 sess_local[s].cin += len;
1575 sess_local[s].pin++;
1576
1577 eth_tx += len;
1578
1579 STAT(tun_tx_packets);
1580 INC_STAT(tun_tx_bytes, len - 4);
1581 }
1582
1583
1584 // Process CCP messages
1585 void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1586 {
1587 uint8_t b[MAXETHER];
1588 uint8_t *q;
1589
1590 CSTAT(processccp);
1591
1592 LOG_HEX(5, "CCP", p, l);
1593
1594 if (session[s].ppp.phase < Network)
1595 {
1596 LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1597 return;
1598 }
1599
1600 if (l < 1)
1601 {
1602 LOG(1, s, t, "Short CCP packet\n");
1603 STAT(tunnel_rx_errors);
1604 }
1605
1606 LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
1607 if (*p == ConfigAck)
1608 {
1609 switch (session[s].ppp.ccp)
1610 {
1611 case RequestSent:
1612 initialise_restart_count(s, ccp);
1613 change_state(s, ccp, AckReceived);
1614 break;
1615
1616 case AckReceived:
1617 case Opened:
1618 LOG(2, s, t, "CCP: ConfigAck in state %s? Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
1619 sendccp(s, t);
1620 change_state(s, ccp, RequestSent);
1621 break;
1622
1623 case AckSent:
1624 LOG(3, s, t, "CCP: Opened\n");
1625 change_state(s, ccp, Opened);
1626 break;
1627
1628 default:
1629 LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1630 }
1631 }
1632 else if (*p == ConfigReq)
1633 {
1634 if (l < 6) // accept no compression
1635 *p = ConfigAck;
1636 else // compression requested--reject
1637 *p = ConfigRej;
1638
1639 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1640 if (!q) return;
1641
1642 switch (session[s].ppp.ccp)
1643 {
1644 case Closed:
1645 q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
1646 if (!q) return;
1647 *q = TerminateAck;
1648 *((uint16_t *) (q + 2)) = htons(l = 4);
1649 break;
1650
1651 case Stopped:
1652 initialise_restart_count(s, ccp);
1653 sendccp(s, t);
1654 if (*q == ConfigAck)
1655 change_state(s, ccp, AckSent);
1656 else
1657 change_state(s, ccp, RequestSent);
1658
1659 break;
1660
1661 case RequestSent:
1662 if (*q == ConfigAck)
1663 change_state(s, ccp, AckSent);
1664
1665 break;
1666
1667 case AckReceived:
1668 if (*q == ConfigAck)
1669 change_state(s, ccp, Opened);
1670
1671 break;
1672
1673 case Opened:
1674 initialise_restart_count(s, ccp);
1675 sendccp(s, t);
1676 /* fallthrough */
1677
1678 case AckSent:
1679 if (*q == ConfigAck)
1680 change_state(s, ccp, AckSent);
1681 else
1682 change_state(s, ccp, RequestSent);
1683
1684 break;
1685
1686 default:
1687 LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1688 return;
1689 }
1690
1691 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1692 tunnelsend(b, l + (q - b), t);
1693 }
1694 else if (*p == TerminateReq)
1695 {
1696 *p = TerminateAck;
1697 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1698 if (!q) return;
1699 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1700 tunnelsend(b, l + (q - b), t);
1701 change_state(s, ccp, Stopped);
1702 }
1703 else if (*p != CodeRej)
1704 {
1705 ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
1706 }
1707 }
1708
1709 // send a CHAP challenge
1710 void sendchap(sessionidt s, tunnelidt t)
1711 {
1712 uint8_t b[MAXETHER];
1713 uint16_t r;
1714 uint8_t *q;
1715
1716 CSTAT(sendchap);
1717
1718 r = radiusnew(s);
1719 if (!r)
1720 {
1721 LOG(1, s, t, "No RADIUS to send challenge\n");
1722 STAT(tunnel_tx_errors);
1723 return;
1724 }
1725
1726 LOG(1, s, t, "Send CHAP challenge\n");
1727
1728 radius[r].chap = 1; // CHAP not PAP
1729 radius[r].id++;
1730 if (radius[r].state != RADIUSCHAP)
1731 radius[r].try = 0;
1732
1733 radius[r].state = RADIUSCHAP;
1734 radius[r].retry = backoff(radius[r].try++);
1735 if (radius[r].try > 5)
1736 {
1737 sessionshutdown(s, "CHAP timeout.", 3, 0);
1738 STAT(tunnel_tx_errors);
1739 return ;
1740 }
1741 q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
1742 if (!q) return;
1743
1744 *q = 1; // challenge
1745 q[1] = radius[r].id; // ID
1746 q[4] = 16; // value size (size of challenge)
1747 memcpy(q + 5, radius[r].auth, 16); // challenge
1748 strcpy((char *) q + 21, hostname); // our name
1749 *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1750 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1751 }
1752
1753 // fill in a L2TP message with a PPP frame,
1754 // copies existing PPP message and changes magic number if seen
1755 // returns start of PPP frame
1756 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
1757 {
1758 if (size < 12) // Need more space than this!!
1759 {
1760 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1761 return NULL;
1762 }
1763
1764 *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1765 *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1766 *(uint16_t *) (b + 4) = htons(session[s].far); // session
1767 b += 6;
1768 if (mtype == PPPLCP || !(session[s].flags & SESSION_ACFC))
1769 {
1770 *(uint16_t *) b = htons(0xFF03); // HDLC header
1771 b += 2;
1772 }
1773 if (mtype < 0x100 && session[s].flags & SESSION_PFC)
1774 *b++ = mtype;
1775 else
1776 {
1777 *(uint16_t *) b = htons(mtype);
1778 b += 2;
1779 }
1780
1781 if (l + 12 > size)
1782 {
1783 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1784 return NULL;
1785 }
1786
1787 if (p && l)
1788 memcpy(b, p, l);
1789
1790 return b;
1791 }
1792
1793 static int add_lcp_auth(uint8_t *b, int size, int authtype)
1794 {
1795 int len = 0;
1796 if ((authtype == AUTHCHAP && size < 5) || size < 4)
1797 return 0;
1798
1799 *b++ = 3; // Authentication-Protocol
1800 if (authtype == AUTHCHAP)
1801 {
1802 len = *b++ = 5; // length
1803 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1804 *b++ = 5; // MD5
1805 }
1806 else if (authtype == AUTHPAP)
1807 {
1808 len = *b++ = 4; // length
1809 *(uint16_t *) b = htons(PPPPAP); b += 2;
1810 }
1811 else
1812 {
1813 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1814 }
1815
1816 return len;
1817 }
1818
1819 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1820 void sendlcp(sessionidt s, tunnelidt t)
1821 {
1822 uint8_t b[500], *q, *l;
1823 int authtype = sess_local[s].lcp_authtype;
1824
1825 if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
1826 return;
1827
1828 LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
1829 authtype ? " (" : "",
1830 authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
1831 authtype ? ")" : "");
1832
1833 l = q;
1834 *l++ = ConfigReq;
1835 *l++ = ++sess_local[s].lcp_ident; // ID
1836
1837 l += 2; //Save space for length
1838
1839 if (sess_local[s].ppp_mru)
1840 {
1841 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1842 *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
1843 }
1844
1845 if (authtype)
1846 l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1847
1848 *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1849 *(uint32_t *) l = htonl(session[s].magic);
1850 l += 4;
1851
1852 *(uint16_t *)(q + 2) = htons(l - q); // Length
1853
1854 LOG_HEX(5, "PPPLCP", q, l - q);
1855 if (config->debug > 3) dumplcp(q, l - q);
1856
1857 tunnelsend(b, (l - b), t);
1858 restart_timer(s, lcp);
1859 }
1860
1861 // Send CCP request for no compression
1862 void sendccp(sessionidt s, tunnelidt t)
1863 {
1864 uint8_t b[500], *q;
1865
1866 if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
1867 return;
1868
1869 LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
1870
1871 *q = ConfigReq;
1872 *(q + 1) = ++sess_local[s].lcp_ident; // ID
1873 *(uint16_t *)(q + 2) = htons(4); // Length
1874
1875 LOG_HEX(5, "PPPCCP", q, 4);
1876 tunnelsend(b, (q - b) + 4 , t);
1877 restart_timer(s, ccp);
1878 }
1879
1880 // Reject unknown/unconfigured protocols
1881 void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
1882 {
1883
1884 uint8_t buf[MAXETHER];
1885 uint8_t *q;
1886 int mru = session[s].mru;
1887 if (mru < MINMTU) mru = MINMTU;
1888 if (mru > sizeof(buf)) mru = sizeof(buf);
1889
1890 l += 6;
1891 if (l > mru) l = mru;
1892
1893 q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
1894 if (!q) return;
1895
1896 *q = ProtocolRej;
1897 *(q + 1) = ++sess_local[s].lcp_ident;
1898 *(uint16_t *)(q + 2) = htons(l);
1899 *(uint16_t *)(q + 4) = htons(proto);
1900 memcpy(q + 6, p, l - 6);
1901
1902 if (proto == PPPIPV6CP)
1903 LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
1904 else
1905 LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
1906
1907 tunnelsend(buf, l + (q - buf), t);
1908 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"