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[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.60 2005/05/10 11:23:33 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 void initccp(tunnelidt t, sessionidt s);
27 static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype);
28
29 // Process PAP messages
30 void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
31 {
32 char user[MAXUSER];
33 char pass[MAXPASS];
34 uint16_t hl;
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 {
65 uint8_t *b = p;
66 b += 4;
67 user[0] = pass[0] = 0;
68 if (*b && *b < sizeof(user))
69 {
70 memcpy(user, b + 1, *b);
71 user[*b] = 0;
72 b += 1 + *b;
73 if (*b && *b < sizeof(pass))
74 {
75 memcpy(pass, b + 1, *b);
76 pass[*b] = 0;
77 }
78 }
79 LOG(3, s, t, "PAP login %s/%s\n", user, pass);
80 }
81 if (session[s].ip || !sess_local[s].radius)
82 {
83 // respond now, either no RADIUS available or already authenticated
84 uint8_t b[MAXCONTROL];
85 uint8_t id = p[1];
86 uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
87 if (!p) return;
88
89 if (session[s].ip)
90 *p = 2; // ACK
91 else
92 *p = 3; // cant authorise
93 p[1] = id;
94 *(uint16_t *) (p + 2) = htons(5); // length
95 p[4] = 0; // no message
96 if (session[s].ip)
97 {
98 LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
99 fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
100
101 session[s].flags &= ~SF_IPCP_ACKED;
102 }
103 else
104 {
105 LOG(1, s, t, "No radius session available to authenticate session...\n");
106 }
107 LOG(3, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
108 tunnelsend(b, 5 + (p - b), t); // send it
109 sessionshutdown(s, "PAP authentication failed.", 3, 0);
110 }
111 else
112 {
113 // set up RADIUS request
114 uint16_t r = sess_local[s].radius;
115
116 // Run PRE_AUTH plugins
117 struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
118 run_plugins(PLUGIN_PRE_AUTH, &packet);
119 if (!packet.continue_auth)
120 {
121 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
122 if (packet.username) free(packet.username);
123 if (packet.password) free(packet.password);
124 return;
125 }
126
127 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
128 strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
129
130 free(packet.username);
131 free(packet.password);
132
133 radius[r].id = p[1];
134 LOG(3, s, t, "Sending login for %s/%s to radius\n", user, pass);
135 radiussend(r, RADIUSAUTH);
136 }
137 }
138
139 // Process CHAP messages
140 void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
141 {
142 uint16_t r;
143 uint16_t hl;
144
145 CSTAT(processchap);
146
147 LOG_HEX(5, "CHAP", p, l);
148 r = sess_local[s].radius;
149 if (!r)
150 {
151 LOG(1, s, t, "Unexpected CHAP message\n");
152 STAT(tunnel_rx_errors);
153 sessionshutdown(s, "Unexpected CHAP message.", 3, 0);
154 return;
155 }
156
157 if (l < 4)
158 {
159 LOG(1, s, t, "Short CHAP %u bytes\n", l);
160 STAT(tunnel_rx_errors);
161 sessionshutdown(s, "Short CHAP packet.", 3, 0);
162 return;
163 }
164
165 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
166 {
167 LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
168 STAT(tunnel_rx_errors);
169 sessionshutdown(s, "CHAP length mismatch.", 3, 0);
170 return;
171 }
172 l = hl;
173
174 if (*p != 2)
175 {
176 LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
177 STAT(tunnel_rx_errors);
178 sessionshutdown(s, "CHAP length mismatch.", 3, 0);
179 return;
180 }
181 if (p[1] != radius[r].id)
182 {
183 LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
184 STAT(tunnel_rx_errors);
185 sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0);
186 return;
187 }
188
189 if (l < 5 || p[4] != 16)
190 {
191 LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
192 STAT(tunnel_rx_errors);
193 sessionshutdown(s, "Bad CHAP response length.", 3, 0);
194 return;
195 }
196
197 l -= 5;
198 p += 5;
199 if (l < 16 || l - 16 >= sizeof(session[s].user))
200 {
201 LOG(1, s, t, "CHAP user too long %d\n", l - 16);
202 STAT(tunnel_rx_errors);
203 sessionshutdown(s, "CHAP username too long.", 3, 0);
204 return;
205 }
206
207 // Run PRE_AUTH plugins
208 {
209 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
210
211 packet.password = calloc(17, 1);
212 memcpy(packet.password, p, 16);
213
214 p += 16;
215 l -= 16;
216
217 packet.username = calloc(l + 1, 1);
218 memcpy(packet.username, p, l);
219
220 run_plugins(PLUGIN_PRE_AUTH, &packet);
221 if (!packet.continue_auth)
222 {
223 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
224 if (packet.username) free(packet.username);
225 if (packet.password) free(packet.password);
226 return;
227 }
228
229 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
230 memcpy(radius[r].pass, packet.password, 16);
231
232 free(packet.username);
233 free(packet.password);
234 }
235
236 radius[r].chap = 1;
237 LOG(3, s, t, "CHAP login %s\n", session[s].user);
238 radiussend(r, RADIUSAUTH);
239 }
240
241 static void dumplcp(uint8_t *p, int l)
242 {
243 int x = l - 4;
244 uint8_t *o = (p + 4);
245
246 LOG_HEX(5, "PPP LCP Packet", p, l);
247 LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_type((int)*p), ntohs( ((uint16_t *) p)[1]) );
248 LOG(4, 0, 0, "Length: %d\n", l);
249 if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
250 return;
251
252 while (x > 2)
253 {
254 int type = o[0];
255 int length = o[1];
256 if (length < 2)
257 {
258 LOG(4, 0, 0, " Option length is %d...\n", length);
259 break;
260 }
261 if (type == 0)
262 {
263 LOG(4, 0, 0, " Option type is 0...\n");
264 x -= length;
265 o += length;
266 continue;
267 }
268 switch (type)
269 {
270 case 1: // Maximum-Receive-Unit
271 if (length == 4)
272 LOG(4, 0, 0, " %s %d\n", lcp_type(type), ntohs(*(uint16_t *)(o + 2)));
273 else
274 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
275 break;
276 case 2: // Async-Control-Character-Map
277 if (length == 6)
278 {
279 uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
280 LOG(4, 0, 0, " %s %x\n", lcp_type(type), asyncmap);
281 }
282 else
283 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
284 break;
285 case 3: // Authentication-Protocol
286 if (length == 4)
287 {
288 int proto = ntohs(*(uint16_t *)(o + 2));
289 LOG(4, 0, 0, " %s 0x%x (%s)\n", lcp_type(type), proto,
290 proto == PPPPAP ? "PAP" : "UNSUPPORTED");
291 }
292 else if (length == 5)
293 {
294 int proto = ntohs(*(uint16_t *)(o + 2));
295 int algo = *(uint8_t *)(o + 4);
296 LOG(4, 0, 0, " %s 0x%x 0x%x (%s)\n", lcp_type(type), proto, algo,
297 (proto == PPPCHAP && algo == 5) ? "CHAP MD5" : "UNSUPPORTED");
298 }
299 else
300 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
301 break;
302 case 4: // Quality-Protocol
303 {
304 uint32_t qp = ntohl(*(uint32_t *)(o + 2));
305 LOG(4, 0, 0, " %s %x\n", lcp_type(type), qp);
306 }
307 break;
308 case 5: // Magic-Number
309 if (length == 6)
310 {
311 uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
312 LOG(4, 0, 0, " %s %x\n", lcp_type(type), magicno);
313 }
314 else
315 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
316 break;
317 case 7: // Protocol-Field-Compression
318 case 8: // Address-And-Control-Field-Compression
319 LOG(4, 0, 0, " %s\n", lcp_type(type));
320 break;
321 default:
322 LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type);
323 break;
324 }
325 x -= length;
326 o += length;
327 }
328 }
329
330 // Process LCP messages
331 void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
332 {
333 uint8_t b[MAXCONTROL];
334 uint8_t *q = NULL;
335 uint32_t magicno = 0;
336 uint16_t hl;
337
338 CSTAT(processlcp);
339
340 LOG_HEX(5, "LCP", p, l);
341 if (l < 4)
342 {
343 LOG(1, s, t, "Short LCP %d bytes\n", l);
344 STAT(tunnel_rx_errors);
345 return ;
346 }
347
348 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
349 {
350 LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
351 STAT(tunnel_rx_errors);
352 return ;
353 }
354 l = hl;
355
356 if (*p == ConfigAck)
357 {
358 int x = l - 4;
359 uint8_t *o = (p + 4);
360
361 LOG(3, s, t, "LCP: ConfigAck (%d bytes)...\n", l);
362 if (config->debug > 3) dumplcp(p, l);
363
364 while (x > 2)
365 {
366 int type = o[0];
367 int length = o[1];
368
369 if (length == 0 || type == 0 || x < length) break;
370 switch (type)
371 {
372 case 3: // Authentication-Protocol
373 {
374 int proto = ntohs(*(uint16_t *)(o + 2));
375 if (proto == PPPCHAP && *(o + 4) == 5)
376 sendchap(t, s);
377 }
378
379 break;
380 }
381 x -= length;
382 o += length;
383 }
384
385 session[s].flags |= SF_LCP_ACKED;
386 }
387 else if (*p == ConfigReq)
388 {
389 int x = l - 4;
390 uint8_t *o = (p + 4);
391 uint8_t *response = 0;
392
393 LOG(3, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
394 if (config->debug > 3) dumplcp(p, l);
395
396 while (x > 2)
397 {
398 int type = o[0];
399 int length = o[1];
400
401 if (length == 0 || type == 0 || x < length) break;
402 switch (type)
403 {
404 case 1: // Maximum-Receive-Unit
405 session[s].mru = ntohs(*(uint16_t *)(o + 2));
406 break;
407
408 case 2: // Async-Control-Character-Map
409 if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
410 break;
411
412 if (response && *response != ConfigNak) // rej already queued
413 break;
414
415 LOG(2, s, t, " Remote requesting asyncmap. Rejecting.\n");
416 if (!response)
417 {
418 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
419 if (!q) break;
420 *q = ConfigNak;
421 q += 4;
422 }
423
424 if ((q - b + 11) > sizeof(b))
425 {
426 LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n");
427 break;
428 }
429
430 *q++ = type;
431 *q++ = 6;
432 memset(q, 0, 4); // asyncmap 0
433 q += 4;
434 break;
435
436 case 3: // Authentication-Protocol
437 {
438 int proto = ntohs(*(uint16_t *)(o + 2));
439 char proto_name[] = "0x0000";
440 uint8_t *a;
441
442 if (proto == PPPPAP)
443 {
444 if (config->radius_authtypes & AUTHPAP)
445 break;
446
447 strcpy(proto_name, "PAP");
448 }
449 else if (proto == PPPCHAP)
450 {
451 if (config->radius_authtypes & AUTHCHAP
452 && *(o + 4) == 5) // MD5
453 break;
454
455 strcpy(proto_name, "CHAP");
456 }
457 else
458 sprintf(proto_name, "%#4.4x", proto);
459
460 if (response && *response != ConfigNak) // rej already queued
461 break;
462
463 LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
464
465 if (!response)
466 {
467 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
468 if (!q) break;
469 *q = ConfigNak;
470 q += 4;
471 }
472
473 a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authprefer);
474 if (!a)
475 {
476 LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
477 break;
478 }
479
480 q = a;
481
482 if (config->radius_authtypes != config->radius_authprefer)
483 {
484 a = add_lcp_auth(q, sizeof(b) - (q - b), config->radius_authtypes & ~config->radius_authprefer);
485 if (!a)
486 {
487 LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
488 break;
489 }
490
491 q = a;
492 }
493
494 break;
495 }
496 break;
497
498 case 5: // Magic-Number
499 magicno = ntohl(*(uint32_t *)(o + 2));
500 break;
501
502 case 4: // Quality-Protocol
503 case 7: // Protocol-Field-Compression
504 case 8: // Address-And-Control-Field-Compression
505 break;
506
507 default: // Reject any unknown options
508 LOG(2, s, t, " Rejecting PPP LCP Option type %d\n", type);
509 if (!response || *response != ConfigRej) // drop nak in favour of rej
510 {
511 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
512 if (!q) break;
513 *q = ConfigRej;
514 q += 4;
515 }
516
517 if ((q - b + length) > sizeof(b))
518 {
519 LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
520 break;
521 }
522
523 memcpy(q, o, length);
524 q += length;
525 }
526 x -= length;
527 o += length;
528 }
529
530 if (response)
531 {
532 l = q - response; // LCP packet length
533 *((uint16_t *) (response + 2)) = htons(l); // update header
534 }
535 else
536 {
537 // Send packet back as ConfigAck
538 response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
539 if (!response) return;
540 *response = ConfigAck;
541 }
542
543 LOG(3, s, t, "Sending %s\n", ppp_lcp_type(*response));
544 tunnelsend(b, l + response - b, t);
545
546 if (!(session[s].flags & SF_LCP_ACKED))
547 sendlcp(t, s, config->radius_authprefer);
548 }
549 else if (*p == ConfigNak)
550 {
551 int x = l - 4;
552 uint8_t *o = (p + 4);
553 int authtype = -1;
554
555 LOG(3, s, t, "LCP: ConfigNak (%d bytes)...\n", l);
556 if (config->debug > 3) dumplcp(p, l);
557
558 while (x > 2)
559 {
560 int type = o[0];
561 int length = o[1];
562
563 if (length == 0 || type == 0 || x < length) break;
564 switch (type)
565 {
566 case 1: // Maximum-Receive-Unit
567 session[s].mru = ntohs(*(uint16_t *)(o + 2));
568 LOG(3, s, t, " Remote requested MRU of %u\n", session[s].mru);
569 break;
570
571 case 3: // Authentication-Protocol
572 if (authtype > 0)
573 break;
574
575 {
576 int proto = ntohs(*(uint16_t *)(o + 2));
577 if (proto == PPPPAP)
578 {
579 authtype = config->radius_authtypes & AUTHPAP;
580 LOG(3, s, t, " Remote requested PAP authentication...%sing\n",
581 authtype ? "accept" : "reject");
582 }
583 else if (proto == PPPCHAP && *(o + 4) == 5)
584 {
585 authtype = config->radius_authtypes & AUTHCHAP;
586 LOG(3, s, t, " Remote requested CHAP authentication...%sing\n",
587 authtype ? "accept" : "reject");
588 }
589 else
590 {
591 LOG(3, s, t, " Rejecting unsupported authentication %#4x\n",
592 proto);
593 }
594 }
595
596 break;
597
598 default:
599 LOG(2, s, t, " Remote NAKed LCP type %u?\n", type);
600 break;
601 }
602 x -= length;
603 o += length;
604 }
605
606 if (!authtype)
607 {
608 sessionshutdown(s, "Unsupported authentication.", 3, 0);
609 return;
610 }
611
612 if (authtype == -1)
613 authtype = config->radius_authprefer;
614
615 sendlcp(t, s, authtype);
616 }
617 else if (*p == TerminateReq)
618 {
619 LOG(3, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
620 *p = TerminateAck; // close
621 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
622 if (!q) return;
623 tunnelsend(b, l + (q - b), t); // send it
624 sessionshutdown(s, "Remote end closed connection.", 3, 0);
625 }
626 else if (*p == TerminateAck)
627 {
628 sessionshutdown(s, "Connection closed.", 3, 0);
629 }
630 else if (*p == ProtocolRej)
631 {
632 if (*(uint16_t *) (p+4) == htons(PPPIPV6CP))
633 {
634 LOG(3, s, t, "IPv6 rejected\n");
635 session[s].flags |= SF_IPV6_NACKED;
636 }
637 else
638 {
639 LOG(1, s, t, "Unexpected LCP protocol reject 0x%X\n",
640 ntohs(*(uint16_t *) (p+4)));
641 STAT(tunnel_rx_errors);
642 }
643 }
644 else if (*p == EchoReq)
645 {
646 LOG(5, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
647 *p = EchoReply; // reply
648 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
649 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
650 if (!q) return;
651 tunnelsend(b, l + (q - b), t); // send it
652 }
653 else if (*p == EchoReply)
654 {
655 // Ignore it, last_packet time is set earlier than this.
656 }
657 else if (*p == IdentRequest)
658 {
659 *p = CodeRej;
660 if (l > MAXCONTROL)
661 {
662 LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
663 l = 1400;
664 }
665 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
666 if (!q) return;
667 LOG_HEX(5, "LCPIdentRej", q, l + 4);
668 tunnelsend(b, 12 + 4 + l, t);
669 }
670 else
671 {
672 LOG(1, s, t, "Unexpected LCP code %d\n", *p);
673 STAT(tunnel_rx_errors);
674 }
675 }
676
677 // find a PPP option, returns point to option, or 0 if not found
678 static uint8_t *findppp(uint8_t *b, uint8_t mtype)
679 {
680 uint16_t l = ntohs(*(uint16_t *) (b + 2));
681 if (l < 4)
682 return 0;
683 b += 4;
684 l -= 4;
685 while (l)
686 {
687 if (l < b[1] || !b[1])
688 return 0; // faulty
689 if (*b == mtype)
690 return b;
691 l -= b[1];
692 b += b[1];
693 }
694 return 0;
695 }
696
697 // Process IPCP messages
698 void processipcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
699 {
700 uint16_t hl;
701
702 CSTAT(processipcp);
703
704 LOG_HEX(5, "IPCP", p, l);
705 if (l < 5)
706 {
707 LOG(1, s, t, "Short IPCP %d bytes\n", l);
708 STAT(tunnel_rx_errors);
709 return ;
710 }
711
712 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
713 {
714 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
715 STAT(tunnel_rx_errors);
716 return ;
717 }
718 l = hl;
719
720 if (*p == ConfigAck)
721 {
722 // happy with our IPCP
723 uint16_t r = sess_local[s].radius;
724 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
725 {
726 if (!r)
727 r = radiusnew(s);
728 if (r)
729 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
730 }
731 session[s].flags |= SF_IPCP_ACKED;
732
733 LOG(3, s, t, "IPCP Acked, session is now active\n");
734
735 // clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
736 session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
737
738 return;
739 }
740 if (*p != ConfigReq)
741 {
742 LOG(1, s, t, "Unexpected IPCP code %d\n", *p);
743 STAT(tunnel_rx_errors);
744 return ;
745 }
746 LOG(4, s, t, "IPCP ConfigReq received\n");
747
748 if (!session[s].ip)
749 {
750 LOG(3, s, t, "Waiting on radius reply\n");
751 return; // have to wait on RADIUS reply
752 }
753 // form a config reply quoting the IP in the session
754 {
755 uint8_t b[MAXCONTROL];
756 uint8_t *i, *q;
757
758 q = p + 4;
759 i = p + l;
760 while (q < i && q[1])
761 {
762 if (*q != 0x81 && *q != 0x83 && *q != 3)
763 break;
764 q += q[1];
765 }
766 if (q < i)
767 {
768 // reject
769 uint16_t n = 4;
770 i = p + l;
771 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
772 return;
773
774 *q = ConfigRej;
775 p += 4;
776 while (p < i && p[1])
777 {
778 if (*p != 0x81 && *p != 0x83 && *p != 3)
779 {
780 LOG(2, s, t, "IPCP reject %d\n", *p);
781 memcpy(q + n, p, p[1]);
782 n += p[1];
783 }
784 p += p[1];
785 }
786 *(uint16_t *) (q + 2) = htons(n);
787 LOG(4, s, t, "Sending ConfigRej\n");
788 tunnelsend(b, n + (q - b), t); // send it
789 }
790 else
791 {
792 LOG(4, s, t, "Sending ConfigAck\n");
793 *p = ConfigAck;
794 if ((i = findppp(p, 0x81))) // Primary DNS address
795 {
796 if (*(uint32_t *) (i + 2) != htonl(session[s].dns1))
797 {
798 *(uint32_t *) (i + 2) = htonl(session[s].dns1);
799 *p = ConfigNak;
800 LOG(5, s, t, " DNS1 = %s\n",
801 fmtaddr(htonl(session[s].dns1), 0));
802 }
803 }
804 if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
805 {
806 if (*(uint32_t *) (i + 2) != htonl(session[s].dns2))
807 {
808 *(uint32_t *) (i + 2) = htonl(session[s].dns2);
809 *p = ConfigNak;
810 LOG(5, s, t, " DNS2 = %s\n",
811 fmtaddr(htonl(session[s].dns2), 0));
812 }
813 }
814 i = findppp(p, 3); // IP address
815 if (!i || i[1] != 6)
816 {
817 LOG(1, s, t, "No IP in IPCP request\n");
818 STAT(tunnel_rx_errors);
819 return ;
820 }
821 if (*(uint32_t *) (i + 2) != htonl(session[s].ip))
822 {
823 *(uint32_t *) (i + 2) = htonl(session[s].ip);
824 *p = ConfigNak;
825 LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
826 fmtaddr(htonl(session[s].ip), 0));
827 }
828 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
829 return;
830
831 tunnelsend(b, l + (q - b), t); // send it
832 }
833 }
834 }
835
836 // Process IPV6CP messages
837 void processipv6cp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
838 {
839
840 CSTAT(processipv6cp);
841
842 LOG_HEX(5, "IPV6CP", p, l);
843 if (l < 4)
844 {
845 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
846 STAT(tunnel_rx_errors);
847 return ;
848 }
849 if (*p == ConfigAck)
850 {
851 // happy with our IPV6CP
852 session[s].flags |= SF_IPV6CP_ACKED;
853
854 LOG(3, s, t, "IPV6CP Acked, IPv6 is now active\n");
855 // Add a routed block if configured.
856 if (session[s].ipv6prefixlen)
857 {
858 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
859 session[s].flags |= SF_IPV6_ROUTED;
860 }
861
862 // Send an initial RA (TODO: Should we send these regularly?)
863 send_ipv6_ra(t, s, NULL);
864 return;
865 }
866 if (*p != ConfigReq)
867 {
868 LOG(1, s, t, "Unexpected IPV6CP code %d\n", *p);
869 STAT(tunnel_rx_errors);
870 return;
871 }
872
873 LOG(4, s, t, "IPV6CP ConfigReq received\n");
874 if (ntohs(*(uint16_t *) (p + 2)) > l)
875 {
876 LOG(1, s, t, "Length mismatch IPV6CP %d/%d\n", ntohs(*(uint16_t *) (p + 2)), l);
877 STAT(tunnel_rx_errors);
878 return ;
879 }
880 if (!session[s].ip)
881 {
882 LOG(3, s, t, "Waiting on radius reply\n");
883 return; // have to wait on RADIUS reply
884 }
885 // form a config reply quoting the IP in the session
886 {
887 uint8_t b[MAXCONTROL];
888 uint8_t *i,
889 *q;
890
891 l = ntohs(*(uint16_t *) (p + 2)); // We must use length from IPV6CP len field
892 q = p + 4;
893 i = p + l;
894 while (q < i && q[1])
895 {
896 if (*q != 1)
897 break;
898 q += q[1];
899 }
900 if (q < i)
901 {
902 // reject
903 uint16_t n = 4;
904 i = p + l;
905 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
906 {
907 LOG(2, s, t, "Failed to send IPV6CP ConfigRej\n");
908 return;
909 }
910 *q = ConfigRej;
911 p += 4;
912 while (p < i && p[1])
913 {
914 if (*p != 1)
915 {
916 LOG(2, s, t, "IPV6CP reject %d\n", *p);
917 memcpy(q + n, p, p[1]);
918 n += p[1];
919 }
920 p += p[1];
921 }
922 *(uint16_t *) (q + 2) = htons(n);
923 LOG(4, s, t, "Sending ConfigRej\n");
924 tunnelsend(b, n + (q - b), t); // send it
925 }
926 else
927 {
928 LOG(4, s, t, "Sending ConfigAck\n");
929 *p = ConfigAck;
930 i = findppp(p, 1); // IP address
931 if (!i || i[1] != 10)
932 {
933 LOG(1, s, t, "No IP in IPV6CP request\n");
934 STAT(tunnel_rx_errors);
935 return ;
936 }
937 if ((*(uint32_t *) (i + 2) != htonl(session[s].ip)) ||
938 (*(uint32_t *) (i + 6) != 0))
939 {
940 *(uint32_t *) (i + 2) = htonl(session[s].ip);
941 *(uint32_t *) (i + 6) = 0;
942 *p = ConfigNak;
943 LOG(4, s, t,
944 " No, a ConfigNak, client is "
945 "requesting IP - sending %s\n",
946 fmtaddr(htonl(session[s].ip), 0));
947 }
948 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
949 {
950 LOG(2, s, t, " Failed to send IPV6CP packet.\n");
951 return;
952 }
953 tunnelsend(b, l + (q - b), t); // send it
954 }
955 }
956 }
957
958 // process IP packet received
959 //
960 // This MUST be called with at least 4 byte behind 'p'.
961 // (i.e. this routine writes to p[-4]).
962 void processipin(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
963 {
964 in_addr_t ip;
965
966 CSTAT(processipin);
967
968 LOG_HEX(5, "IP", p, l);
969
970 ip = ntohl(*(uint32_t *)(p + 12));
971
972 if (l > MAXETHER)
973 {
974 LOG(1, s, t, "IP packet too long %d\n", l);
975 STAT(tunnel_rx_errors);
976 return ;
977 }
978
979 // no spoof (do sessionbyip to handled statically routed subnets)
980 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
981 {
982 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
983 return;
984 }
985
986 // run access-list if any
987 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
988 return;
989
990 // Add on the tun header
991 p -= 4;
992 *(uint32_t *) p = htonl(PKTIP);
993 l += 4;
994
995 // Are we throttled and a slave?
996 if (session[s].tbf_in && !config->cluster_iam_master) {
997 // Pass it to the master for handling.
998 master_throttle_packet(session[s].tbf_in, p, l);
999 return;
1000 }
1001
1002 // Are we throttled and a master??
1003 if (session[s].tbf_in && config->cluster_iam_master) {
1004 // Actually handle the throttled packets.
1005 tbf_queue_packet(session[s].tbf_in, p, l);
1006 return;
1007 }
1008
1009 // send to ethernet
1010 if (tun_write(p, l) < 0)
1011 {
1012 STAT(tun_tx_errors);
1013 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1014 l, strerror(errno), tunfd, p);
1015
1016 return;
1017 }
1018
1019 if (session[s].snoop_ip && session[s].snoop_port)
1020 {
1021 // Snooping this session
1022 snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
1023 }
1024
1025 session[s].cin += l - 4;
1026 session[s].total_cin += l - 4;
1027 sess_local[s].cin += l - 4;
1028
1029 session[s].pin++;
1030 eth_tx += l - 4;
1031
1032 STAT(tun_tx_packets);
1033 INC_STAT(tun_tx_bytes, l - 4);
1034 }
1035
1036 // process IPv6 packet received
1037 //
1038 // This MUST be called with at least 4 byte behind 'p'.
1039 // (i.e. this routine writes to p[-4]).
1040 void processipv6in(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
1041 {
1042 struct in6_addr ip;
1043 in_addr_t ipv4;
1044
1045 CSTAT(processipv6in);
1046
1047 LOG_HEX(5, "IPv6", p, l);
1048
1049 ip = *(struct in6_addr *) (p + 8);
1050 ipv4 = ntohl(*(uint32_t *)(p + 16));
1051
1052 if (l > MAXETHER)
1053 {
1054 LOG(1, s, t, "IP packet too long %d\n", l);
1055 STAT(tunnel_rx_errors);
1056 return ;
1057 }
1058
1059 // no spoof
1060 if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1061 {
1062 char str[INET6_ADDRSTRLEN];
1063 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1064 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1065 return;
1066 }
1067
1068 // Check if it's a Router Solicition message.
1069 if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1070 *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1071 *(uint32_t *)(p + 34) == 0 &&
1072 *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1073 LOG(3, s, t, "Got IPv6 RS\n");
1074 send_ipv6_ra(t, s, &ip);
1075 return;
1076 }
1077
1078 // Add on the tun header
1079 p -= 4;
1080 *(uint32_t *) p = htonl(PKTIPV6);
1081 l += 4;
1082
1083 // Are we throttled and a slave?
1084 if (session[s].tbf_in && !config->cluster_iam_master) {
1085 // Pass it to the master for handling.
1086 master_throttle_packet(session[s].tbf_in, p, l);
1087 return;
1088 }
1089
1090 // Are we throttled and a master??
1091 if (session[s].tbf_in && config->cluster_iam_master) {
1092 // Actually handle the throttled packets.
1093 tbf_queue_packet(session[s].tbf_in, p, l);
1094 return;
1095 }
1096
1097 // send to ethernet
1098 if (tun_write(p, l) < 0)
1099 {
1100 STAT(tun_tx_errors);
1101 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1102 l, strerror(errno), tunfd, p);
1103
1104 return;
1105 }
1106
1107 if (session[s].snoop_ip && session[s].snoop_port)
1108 {
1109 // Snooping this session
1110 snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
1111 }
1112
1113 session[s].cin += l - 4;
1114 session[s].total_cin += l - 4;
1115 sess_local[s].cin += l - 4;
1116
1117 session[s].pin++;
1118 eth_tx += l - 4;
1119
1120 STAT(tun_tx_packets);
1121 INC_STAT(tun_tx_bytes, l - 4);
1122 }
1123
1124 //
1125 // Helper routine for the TBF filters.
1126 // Used to send queued data in from the user.
1127 //
1128 void send_ipin(sessionidt s, uint8_t *buf, int len)
1129 {
1130 LOG_HEX(5, "IP in throttled", buf, len);
1131
1132 if (write(tunfd, buf, len) < 0)
1133 {
1134 STAT(tun_tx_errors);
1135 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1136 len, strerror(errno), tunfd, buf);
1137
1138 return;
1139 }
1140
1141 if (session[s].snoop_ip && session[s].snoop_port)
1142 {
1143 // Snooping this session
1144 snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
1145 }
1146
1147 // Increment packet counters
1148 session[s].cin += len - 4;
1149 session[s].total_cin += len - 4;
1150 sess_local[s].cin += len - 4;
1151
1152 session[s].pin++;
1153 eth_tx += len - 4;
1154
1155 STAT(tun_tx_packets);
1156 INC_STAT(tun_tx_bytes, len - 4);
1157 }
1158
1159
1160 // Process CCP messages
1161 void processccp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
1162 {
1163 uint8_t b[MAXCONTROL];
1164 uint8_t *q;
1165
1166 CSTAT(processccp);
1167
1168 LOG_HEX(5, "CCP", p, l);
1169 switch (l > 1 ? *p : 0)
1170 {
1171 case ConfigAck:
1172 session[s].flags |= SF_CCP_ACKED;
1173 return;
1174
1175 case ConfigReq:
1176 if (l < 6) // accept no compression
1177 {
1178 *p = ConfigAck;
1179 break;
1180 }
1181
1182 // compression requested--reject
1183 *p = ConfigRej;
1184
1185 // send CCP request for no compression for our end if not negotiated
1186 if (!(session[s].flags & SF_CCP_ACKED))
1187 initccp(t, s);
1188
1189 break;
1190
1191 case TerminateReq:
1192 *p = TerminateAck;
1193 break;
1194
1195 default:
1196 if (l > 1)
1197 LOG(1, s, t, "Unexpected CCP request code %d\n", *p);
1198 else
1199 LOG(1, s, t, "Short CCP packet\n");
1200
1201 STAT(tunnel_rx_errors);
1202 return;
1203 }
1204
1205 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
1206 return;
1207
1208 tunnelsend(b, l + (q - b), t); // send it
1209 }
1210
1211 // send a CHAP challenge
1212 void sendchap(tunnelidt t, sessionidt s)
1213 {
1214 uint8_t b[MAXCONTROL];
1215 uint16_t r = sess_local[s].radius;
1216 uint8_t *q;
1217
1218 CSTAT(sendchap);
1219
1220 if (!r)
1221 {
1222 LOG(1, s, t, "No RADIUS to send challenge\n");
1223 STAT(tunnel_tx_errors);
1224 return;
1225 }
1226
1227 LOG(1, s, t, "Send CHAP challenge\n");
1228
1229 radius[r].chap = 1; // CHAP not PAP
1230 radius[r].id++;
1231 if (radius[r].state != RADIUSCHAP)
1232 radius[r].try = 0;
1233
1234 radius[r].state = RADIUSCHAP;
1235 radius[r].retry = backoff(radius[r].try++);
1236 if (radius[r].try > 5)
1237 {
1238 sessionshutdown(s, "CHAP timeout.", 3, 0);
1239 STAT(tunnel_tx_errors);
1240 return ;
1241 }
1242 q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
1243 if (!q) return;
1244
1245 *q = 1; // challenge
1246 q[1] = radius[r].id; // ID
1247 q[4] = 16; // value size (size of challenge)
1248 memcpy(q + 5, radius[r].auth, 16); // challenge
1249 strcpy(q + 21, hostname); // our name
1250 *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1251 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1252 }
1253
1254 // fill in a L2TP message with a PPP frame,
1255 // copies existing PPP message and changes magic number if seen
1256 // returns start of PPP frame
1257 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, tunnelidt t, sessionidt s, uint16_t mtype)
1258 {
1259 if (size < 12) // Need more space than this!!
1260 {
1261 static int backtrace_count = 0;
1262 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1263 log_backtrace(backtrace_count, 5)
1264 return NULL;
1265 }
1266
1267 *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1268 *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1269 *(uint16_t *) (b + 4) = htons(session[s].far); // session
1270 b += 6;
1271 if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
1272 {
1273 *(uint16_t *) b = htons(0xFF03); // HDLC header
1274 b += 2;
1275 }
1276 if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
1277 *b++ = mtype;
1278 else
1279 {
1280 *(uint16_t *) b = htons(mtype);
1281 b += 2;
1282 }
1283
1284 if (l + 12 > size)
1285 {
1286 static int backtrace_count = 0;
1287 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1288 log_backtrace(backtrace_count, 5)
1289 return NULL;
1290 }
1291
1292 if (p && l)
1293 memcpy(b, p, l);
1294
1295 return b;
1296 }
1297
1298 static uint8_t *add_lcp_auth(uint8_t *b, int size, int authtype)
1299 {
1300 if ((authtype == AUTHCHAP && size < 5) || size < 4)
1301 return 0;
1302
1303 *b++ = 3; // Authentication-Protocol
1304 if (authtype == AUTHCHAP)
1305 {
1306 *b++ = 5; // length
1307 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1308 *b++ = 5; // MD5
1309 }
1310 else if (authtype == AUTHPAP)
1311 {
1312 *b++ = 4; // length
1313 *(uint16_t *) b = htons(PPPPAP); b += 2;
1314 }
1315 else
1316 {
1317 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1318 }
1319
1320 return b;
1321 }
1322
1323 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1324 void sendlcp(tunnelidt t, sessionidt s, int authtype)
1325 {
1326 char b[500], *q, *l;
1327
1328 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
1329 return;
1330
1331 LOG(4, s, t, "Sending LCP ConfigReq for %s\n",
1332 authtype == AUTHCHAP ? "CHAP" : "PAP");
1333
1334 if (!session[s].mru)
1335 session[s].mru = DEFAULT_MRU;
1336
1337 l = q;
1338 *l++ = ConfigReq;
1339 *l++ = (time_now % 255) + 1; // ID
1340
1341 l += 2; //Save space for length
1342
1343 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1344 *(uint16_t *) l = htons(session[s].mru); l += 2;
1345
1346 l = add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1347
1348 *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1349 *(uint32_t *) l = htonl(session[s].magic);
1350 l += 4;
1351
1352 *(uint16_t *)(q + 2) = htons(l - q); // Length
1353
1354 LOG_HEX(5, "PPPLCP", q, l - q);
1355 tunnelsend(b, (l - b), t);
1356 }
1357
1358 // Send CCP request for no compression
1359 static void initccp(tunnelidt t, sessionidt s)
1360 {
1361 char b[500], *q;
1362
1363 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
1364 return;
1365
1366 LOG(4, s, t, "Sending CCP ConfigReq for no compression\n");
1367 *q = ConfigReq;
1368 *(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID
1369 *(uint16_t *)(q + 2) = htons(4); // Length
1370
1371 LOG_HEX(5, "PPPCCP", q, 4);
1372 tunnelsend(b, (q - b) + 4 , t);
1373 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"