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finish incorporating ipv6 patches
[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.42 2005/01/25 04:19:06 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
28 // Process PAP messages
29 void processpap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
30 {
31 char user[129];
32 char pass[129];
33 uint16_t hl;
34
35 CSTAT(processpap);
36
37 LOG_HEX(5, "PAP", p, l);
38 if (l < 4)
39 {
40 LOG(1, s, t, "Short PAP %u bytes\n", l);
41 STAT(tunnel_rx_errors);
42 return ;
43 }
44
45 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
46 {
47 LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
48 STAT(tunnel_rx_errors);
49 return ;
50 }
51 l = hl;
52
53 if (*p != 1)
54 {
55 LOG(1, s, t, "Unexpected PAP code %d\n", *p);
56 STAT(tunnel_rx_errors);
57 return ;
58 }
59
60 {
61 uint8_t *b = p;
62 b += 4;
63 if (*b && *b < sizeof(user))
64 memcpy(user, b + 1, *b);
65 user[*b] = 0;
66 b += 1 + *b;
67 if (*b && *b < sizeof(pass))
68 memcpy(pass, b + 1, *b);
69 pass[*b] = 0;
70 LOG(3, s, t, "PAP login %s/%s\n", user, pass);
71 }
72 if (session[s].ip || !session[s].radius)
73 {
74 // respond now, either no RADIUS available or already authenticated
75 uint8_t b[MAXCONTROL];
76 uint8_t id = p[1];
77 uint8_t *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
78 if (!p) return;
79
80 if (session[s].ip)
81 *p = 2; // ACK
82 else
83 *p = 3; // cant authorise
84 p[1] = id;
85 *(uint16_t *) (p + 2) = htons(5); // length
86 p[4] = 0; // no message
87 if (session[s].ip)
88 {
89 LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
90 fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
91
92 session[s].flags &= ~SF_IPCP_ACKED;
93 }
94 else
95 {
96 LOG(1, s, t, "No radius session available to authenticate session...\n");
97 }
98 LOG(3, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
99 tunnelsend(b, 5 + (p - b), t); // send it
100 }
101 else
102 {
103 // set up RADIUS request
104 uint16_t r = session[s].radius;
105
106 // Run PRE_AUTH plugins
107 struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
108 run_plugins(PLUGIN_PRE_AUTH, &packet);
109 if (!packet.continue_auth)
110 {
111 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
112 if (packet.username) free(packet.username);
113 if (packet.password) free(packet.password);
114 return;
115 }
116
117 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
118 strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
119
120 free(packet.username);
121 free(packet.password);
122
123 radius[r].id = p[1];
124 LOG(3, s, t, "Sending login for %s/%s to radius\n", user, pass);
125 radiussend(r, RADIUSAUTH);
126 }
127 }
128
129 // Process CHAP messages
130 void processchap(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
131 {
132 uint16_t r;
133 uint16_t hl;
134
135 CSTAT(processchap);
136
137 LOG_HEX(5, "CHAP", p, l);
138 r = session[s].radius;
139 if (!r)
140 {
141 LOG(1, s, t, "Unexpected CHAP message\n");
142 STAT(tunnel_rx_errors);
143 return;
144 }
145
146 if (l < 4)
147 {
148 LOG(1, s, t, "Short CHAP %u bytes\n", l);
149 STAT(tunnel_rx_errors);
150 return ;
151 }
152
153 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
154 {
155 LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
156 STAT(tunnel_rx_errors);
157 return ;
158 }
159 l = hl;
160
161 if (*p != 2)
162 {
163 LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
164 STAT(tunnel_rx_errors);
165 return;
166 }
167 if (p[1] != radius[r].id)
168 {
169 LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
170 STAT(tunnel_rx_errors);
171 return ;
172 }
173
174 if (l < 5 || p[4] != 16)
175 {
176 LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
177 STAT(tunnel_rx_errors);
178 return ;
179 }
180
181 l -= 5;
182 p += 5;
183 if (l < 16 || l - 16 >= sizeof(session[s].user))
184 {
185 LOG(1, s, t, "CHAP user too long %d\n", l - 16);
186 STAT(tunnel_rx_errors);
187 return ;
188 }
189
190 // Run PRE_AUTH plugins
191 {
192 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
193
194 packet.password = calloc(17, 1);
195 memcpy(packet.password, p, 16);
196
197 p += 16;
198 l -= 16;
199
200 packet.username = calloc(l + 1, 1);
201 memcpy(packet.username, p, l);
202
203 run_plugins(PLUGIN_PRE_AUTH, &packet);
204 if (!packet.continue_auth)
205 {
206 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
207 if (packet.username) free(packet.username);
208 if (packet.password) free(packet.password);
209 return;
210 }
211
212 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
213 memcpy(radius[r].pass, packet.password, 16);
214
215 free(packet.username);
216 free(packet.password);
217 }
218
219 radius[r].chap = 1;
220 LOG(3, s, t, "CHAP login %s\n", session[s].user);
221 radiussend(r, RADIUSAUTH);
222 }
223
224 static void dumplcp(uint8_t *p, int l)
225 {
226 int x = l - 4;
227 uint8_t *o = (p + 4);
228
229 LOG_HEX(5, "PPP LCP Packet", p, l);
230 LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_type((int)*p), ntohs( ((uint16_t *) p)[1]) );
231 LOG(4, 0, 0, "Length: %d\n", l);
232 if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
233 return;
234
235 while (x > 2)
236 {
237 int type = o[0];
238 int length = o[1];
239 if (length < 2)
240 {
241 LOG(4, 0, 0, " Option length is %d...\n", length);
242 break;
243 }
244 if (type == 0)
245 {
246 LOG(4, 0, 0, " Option type is 0...\n");
247 x -= length;
248 o += length;
249 continue;
250 }
251 switch (type)
252 {
253 case 1: // Maximum-Receive-Unit
254 if (length == 4)
255 LOG(4, 0, 0, " %s %d\n", lcp_type(type), ntohs(*(uint16_t *)(o + 2)));
256 else
257 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
258 break;
259 case 2: // Async-Control-Character-Map
260 if (length == 6)
261 {
262 uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
263 LOG(4, 0, 0, " %s %x\n", lcp_type(type), asyncmap);
264 }
265 else
266 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
267 break;
268 case 3: // Authentication-Protocol
269 if (length == 4)
270 {
271 int proto = ntohs(*(uint16_t *)(o + 2));
272 LOG(4, 0, 0, " %s 0x%x (%s)\n", lcp_type(type), proto,
273 proto == PPPCHAP ? "CHAP" :
274 proto == PPPPAP ? "PAP" : "UNKNOWN");
275 }
276 else
277 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
278 break;
279 case 4: // Quality-Protocol
280 {
281 uint32_t qp = ntohl(*(uint32_t *)(o + 2));
282 LOG(4, 0, 0, " %s %x\n", lcp_type(type), qp);
283 }
284 break;
285 case 5: // Magic-Number
286 if (length == 6)
287 {
288 uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
289 LOG(4, 0, 0, " %s %x\n", lcp_type(type), magicno);
290 }
291 else
292 LOG(4, 0, 0, " %s odd length %d\n", lcp_type(type), length);
293 break;
294 case 7: // Protocol-Field-Compression
295 case 8: // Address-And-Control-Field-Compression
296 LOG(4, 0, 0, " %s\n", lcp_type(type));
297 break;
298 default:
299 LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type);
300 break;
301 }
302 x -= length;
303 o += length;
304 }
305 }
306
307 // Process LCP messages
308 void processlcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
309 {
310 uint8_t b[MAXCONTROL];
311 uint8_t *q = NULL;
312 uint32_t magicno = 0;
313 uint16_t hl;
314
315 CSTAT(processlcp);
316
317 LOG_HEX(5, "LCP", p, l);
318 if (l < 4)
319 {
320 LOG(1, s, t, "Short LCP %d bytes\n", l);
321 STAT(tunnel_rx_errors);
322 return ;
323 }
324
325 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
326 {
327 LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
328 STAT(tunnel_rx_errors);
329 return ;
330 }
331 l = hl;
332
333 if (*p == ConfigAck)
334 {
335 LOG(3, s, t, "LCP: Discarding ConfigAck\n");
336 session[s].flags |= SF_LCP_ACKED;
337 }
338 else if (*p == ConfigReq)
339 {
340 int x = l - 4;
341 uint8_t *o = (p + 4);
342 uint8_t *response = 0;
343
344 LOG(3, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
345 if (config->debug > 3) dumplcp(p, l);
346
347 while (x > 2)
348 {
349 int type = o[0];
350 int length = o[1];
351
352 if (length == 0 || type == 0 || x < length) break;
353 switch (type)
354 {
355 case 1: // Maximum-Receive-Unit
356 session[s].mru = ntohs(*(uint16_t *)(o + 2));
357 break;
358
359 case 2: // Async-Control-Character-Map
360 if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
361 break;
362
363 if (response && *response != ConfigNak) // rej already queued
364 break;
365
366 LOG(2, s, t, " Remote requesting asyncmap. Rejecting.\n");
367 if (!response)
368 {
369 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
370 if (!q) break;
371 *q = ConfigNak;
372 q += 4;
373 }
374
375 if ((q - b + 11) > sizeof(b))
376 {
377 LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n");
378 break;
379 }
380
381 *q++ = type;
382 *q++ = 6;
383 memset(q, 0, 4); // asyncmap 0
384 q += 4;
385 *((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
386 break;
387
388 case 3: // Authentication-Protocol
389 {
390 int proto = ntohs(*(uint16_t *)(o + 2));
391 char proto_name[] = "0x0000";
392 if (proto == PPPPAP)
393 break;
394
395 if (response && *response != ConfigNak) // rej already queued
396 break;
397
398 if (proto == PPPCHAP)
399 strcpy(proto_name, "CHAP");
400 else
401 sprintf(proto_name, "%#4.4x", proto);
402
403 LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
404
405 if (!response)
406 {
407 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
408 if (!q) break;
409 *q = ConfigNak;
410 q += 4;
411 }
412
413 if ((q - b + length) > sizeof(b))
414 {
415 LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
416 break;
417 }
418
419 memcpy(q, o, length);
420 *(uint16_t *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
421 q += length;
422 *((uint16_t *) (response + 2)) = htons(q - response);
423 }
424 break;
425
426 case 5: // Magic-Number
427 magicno = ntohl(*(uint32_t *)(o + 2));
428 break;
429
430 case 4: // Quality-Protocol
431 case 7: // Protocol-Field-Compression
432 case 8: // Address-And-Control-Field-Compression
433 break;
434
435 default: // Reject any unknown options
436 LOG(2, s, t, " Rejecting PPP LCP Option type %d\n", type);
437 if (!response || *response != ConfigRej) // drop nak in favour of rej
438 {
439 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
440 if (!q) break;
441 *q = ConfigRej;
442 q += 4;
443 }
444
445 if ((q - b + length) > sizeof(b))
446 {
447 LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
448 break;
449 }
450
451 memcpy(q, o, length);
452 q += length;
453 *((uint16_t *) (response + 2)) = htons(q - response); // LCP header length
454 }
455 x -= length;
456 o += length;
457 }
458
459 if (!response)
460 {
461 // Send back a ConfigAck
462 q = response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
463 if (!q) return;
464 *q = ConfigAck;
465 }
466
467 LOG(3, s, t, "Sending %s\n", ppp_lcp_type(*response));
468 tunnelsend(b, l + (q - b), t);
469
470 if (!(session[s].flags & SF_LCP_ACKED))
471 initlcp(t, s);
472 }
473 else if (*p == ConfigNak)
474 {
475 LOG(1, s, t, "Remote end sent a ConfigNak. Ignoring\n");
476 if (config->debug > 3) dumplcp(p, l);
477 return ;
478 }
479 else if (*p == TerminateReq)
480 {
481 LOG(3, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
482 *p = TerminateAck; // close
483 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
484 if (!q) return;
485 tunnelsend(b, l + (q - b), t); // send it
486 sessionshutdown(s, "Remote end closed connection.");
487 }
488 else if (*p == TerminateAck)
489 {
490 sessionshutdown(s, "Connection closed.");
491 }
492 else if (*p == ProtocolRej)
493 {
494 if (*(uint16_t *) (p+4) == htons(PPPIPV6CP))
495 {
496 LOG(3, s, t, "IPv6 rejected\n");
497 session[s].flags |= SF_IPV6_NACKED;
498 }
499 else
500 {
501 LOG(1, s, t, "Unexpected LCP protocol reject 0x%X\n",
502 ntohs(*(uint16_t *) (p+4)));
503 STAT(tunnel_rx_errors);
504 }
505 }
506 else if (*p == EchoReq)
507 {
508 LOG(5, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
509 *p = EchoReply; // reply
510 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
511 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
512 if (!q) return;
513 tunnelsend(b, l + (q - b), t); // send it
514 }
515 else if (*p == EchoReply)
516 {
517 // Ignore it, last_packet time is set earlier than this.
518 }
519 else if (*p == IdentRequest)
520 {
521 *p = CodeRej;
522 if (l > MAXCONTROL)
523 {
524 LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
525 l = 1400;
526 }
527 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
528 if (!q) return;
529 LOG_HEX(5, "LCPIdentRej", q, l + 4);
530 tunnelsend(b, 12 + 4 + l, t);
531 }
532 else
533 {
534 LOG(1, s, t, "Unexpected LCP code %d\n", *p);
535 STAT(tunnel_rx_errors);
536 return ;
537 }
538 }
539
540 // find a PPP option, returns point to option, or 0 if not found
541 static uint8_t *findppp(uint8_t *b, uint8_t mtype)
542 {
543 uint16_t l = ntohs(*(uint16_t *) (b + 2));
544 if (l < 4)
545 return 0;
546 b += 4;
547 l -= 4;
548 while (l)
549 {
550 if (l < b[1] || !b[1])
551 return 0; // faulty
552 if (*b == mtype)
553 return b;
554 l -= b[1];
555 b += b[1];
556 }
557 return 0;
558 }
559
560 // Process IPCP messages
561 void processipcp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
562 {
563 uint16_t hl;
564
565 CSTAT(processipcp);
566
567 LOG_HEX(5, "IPCP", p, l);
568 if (l < 5)
569 {
570 LOG(1, s, t, "Short IPCP %d bytes\n", l);
571 STAT(tunnel_rx_errors);
572 return ;
573 }
574
575 if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
576 {
577 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
578 STAT(tunnel_rx_errors);
579 return ;
580 }
581 l = hl;
582
583 if (*p == ConfigAck)
584 {
585 // happy with our IPCP
586 uint16_t r = session[s].radius;
587 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
588 {
589 if (!r)
590 r = radiusnew(s);
591 if (r)
592 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
593 }
594 session[s].flags |= SF_IPCP_ACKED;
595
596 LOG(3, s, t, "IPCP Acked, session is now active\n");
597
598 // clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
599 session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
600
601 return;
602 }
603 if (*p != ConfigReq)
604 {
605 LOG(1, s, t, "Unexpected IPCP code %d\n", *p);
606 STAT(tunnel_rx_errors);
607 return ;
608 }
609 LOG(4, s, t, "IPCP ConfigReq received\n");
610
611 if (!session[s].ip)
612 {
613 LOG(3, s, t, "Waiting on radius reply\n");
614 return; // have to wait on RADIUS reply
615 }
616 // form a config reply quoting the IP in the session
617 {
618 uint8_t b[MAXCONTROL];
619 uint8_t *i, *q;
620
621 q = p + 4;
622 i = p + l;
623 while (q < i && q[1])
624 {
625 if (*q != 0x81 && *q != 0x83 && *q != 3)
626 break;
627 q += q[1];
628 }
629 if (q < i)
630 {
631 // reject
632 uint16_t n = 4;
633 i = p + l;
634 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
635 return;
636
637 *q = ConfigRej;
638 p += 4;
639 while (p < i && p[1])
640 {
641 if (*p != 0x81 && *p != 0x83 && *p != 3)
642 {
643 LOG(2, s, t, "IPCP reject %d\n", *p);
644 memcpy(q + n, p, p[1]);
645 n += p[1];
646 }
647 p += p[1];
648 }
649 *(uint16_t *) (q + 2) = htons(n);
650 LOG(4, s, t, "Sending ConfigRej\n");
651 tunnelsend(b, n + (q - b), t); // send it
652 }
653 else
654 {
655 LOG(4, s, t, "Sending ConfigAck\n");
656 *p = ConfigAck;
657 if ((i = findppp(p, 0x81))) // Primary DNS address
658 {
659 if (*(uint32_t *) (i + 2) != htonl(session[s].dns1))
660 {
661 *(uint32_t *) (i + 2) = htonl(session[s].dns1);
662 *p = ConfigNak;
663 LOG(5, s, t, " DNS1 = %s\n",
664 fmtaddr(htonl(session[s].dns1), 0));
665 }
666 }
667 if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
668 {
669 if (*(uint32_t *) (i + 2) != htonl(session[s].dns2))
670 {
671 *(uint32_t *) (i + 2) = htonl(session[s].dns2);
672 *p = ConfigNak;
673 LOG(5, s, t, " DNS2 = %s\n",
674 fmtaddr(htonl(session[s].dns2), 0));
675 }
676 }
677 i = findppp(p, 3); // IP address
678 if (!i || i[1] != 6)
679 {
680 LOG(1, s, t, "No IP in IPCP request\n");
681 STAT(tunnel_rx_errors);
682 return ;
683 }
684 if (*(uint32_t *) (i + 2) != htonl(session[s].ip))
685 {
686 *(uint32_t *) (i + 2) = htonl(session[s].ip);
687 *p = ConfigNak;
688 LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
689 fmtaddr(htonl(session[s].ip), 0));
690 }
691 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
692 return;
693
694 tunnelsend(b, l + (q - b), t); // send it
695 }
696 }
697 }
698
699 // Process IPV6CP messages
700 void processipv6cp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
701 {
702
703 CSTAT(processipv6cp);
704
705 LOG_HEX(5, "IPV6CP", p, l);
706 if (l < 4)
707 {
708 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
709 STAT(tunnel_rx_errors);
710 return ;
711 }
712 if (*p == ConfigAck)
713 {
714 // happy with our IPV6CP
715 session[s].flags |= SF_IPV6CP_ACKED;
716
717 LOG(3, s, t, "IPV6CP Acked, IPv6 is now active\n");
718 // Add a routed block if configured.
719 if (session[s].ipv6prefixlen)
720 {
721 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
722 session[s].flags |= SF_IPV6_ROUTED;
723 }
724
725 // Send an initial RA (TODO: Should we send these regularly?)
726 send_ipv6_ra(t, s, NULL);
727 return;
728 }
729 if (*p != ConfigReq)
730 {
731 LOG(1, s, t, "Unexpected IPV6CP code %d\n", *p);
732 STAT(tunnel_rx_errors);
733 return;
734 }
735
736 LOG(4, s, t, "IPV6CP ConfigReq received\n");
737 if (ntohs(*(uint16_t *) (p + 2)) > l)
738 {
739 LOG(1, s, t, "Length mismatch IPV6CP %d/%d\n", ntohs(*(uint16_t *) (p + 2)), l);
740 STAT(tunnel_rx_errors);
741 return ;
742 }
743 if (!session[s].ip)
744 {
745 LOG(3, s, t, "Waiting on radius reply\n");
746 return; // have to wait on RADIUS reply
747 }
748 // form a config reply quoting the IP in the session
749 {
750 uint8_t b[MAXCONTROL];
751 uint8_t *i,
752 *q;
753
754 l = ntohs(*(uint16_t *) (p + 2)); // We must use length from IPV6CP len field
755 q = p + 4;
756 i = p + l;
757 while (q < i && q[1])
758 {
759 if (*q != 1)
760 break;
761 q += q[1];
762 }
763 if (q < i)
764 {
765 // reject
766 uint16_t n = 4;
767 i = p + l;
768 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
769 {
770 LOG(2, s, t, "Failed to send IPV6CP ConfigRej\n");
771 return;
772 }
773 *q = ConfigRej;
774 p += 4;
775 while (p < i && p[1])
776 {
777 if (*p != 1)
778 {
779 LOG(2, s, t, "IPV6CP reject %d\n", *p);
780 memcpy(q + n, p, p[1]);
781 n += p[1];
782 }
783 p += p[1];
784 }
785 *(uint16_t *) (q + 2) = htons(n);
786 LOG(4, s, t, "Sending ConfigRej\n");
787 tunnelsend(b, n + (q - b), t); // send it
788 }
789 else
790 {
791 LOG(4, s, t, "Sending ConfigAck\n");
792 *p = ConfigAck;
793 i = findppp(p, 1); // IP address
794 if (!i || i[1] != 10)
795 {
796 LOG(1, s, t, "No IP in IPV6CP request\n");
797 STAT(tunnel_rx_errors);
798 return ;
799 }
800 if ((*(uint32_t *) (i + 2) != htonl(session[s].ip)) ||
801 (*(uint32_t *) (i + 6) != 0))
802 {
803 *(uint32_t *) (i + 2) = htonl(session[s].ip);
804 *(uint32_t *) (i + 6) = 0;
805 *p = ConfigNak;
806 LOG(4, s, t,
807 " No, a ConfigNak, client is "
808 "requesting IP - sending %s\n",
809 fmtaddr(htonl(session[s].ip), 0));
810 }
811 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPV6CP)))
812 {
813 LOG(2, s, t, " Failed to send IPV6CP packet.\n");
814 return;
815 }
816 tunnelsend(b, l + (q - b), t); // send it
817 }
818 }
819 }
820
821 // process IP packet received
822 //
823 // This MUST be called with at least 4 byte behind 'p'.
824 // (i.e. this routine writes to p[-4]).
825 void processipin(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
826 {
827 in_addr_t ip;
828
829 CSTAT(processipin);
830
831 LOG_HEX(5, "IP", p, l);
832
833 ip = ntohl(*(uint32_t *)(p + 12));
834
835 if (l > MAXETHER)
836 {
837 LOG(1, s, t, "IP packet too long %d\n", l);
838 STAT(tunnel_rx_errors);
839 return ;
840 }
841
842 // no spoof (do sessionbyip to handled statically routed subnets)
843 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
844 {
845 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
846 return;
847 }
848
849 // run access-list if any
850 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
851 return;
852
853 // Add on the tun header
854 p -= 4;
855 *(uint32_t *) p = htonl(0x00000800);
856 l += 4;
857
858 if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
859 master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
860 return;
861 }
862
863 if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
864 tbf_queue_packet(session[s].tbf_in, p, l);
865 return;
866 }
867
868 // send to ethernet
869 if (tun_write(p, l) < 0)
870 {
871 STAT(tun_tx_errors);
872 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
873 l, strerror(errno), tunfd, p);
874
875 return;
876 }
877
878 if (session[s].snoop_ip && session[s].snoop_port)
879 {
880 // Snooping this session
881 snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
882 }
883
884 session[s].cin += l - 4;
885 session[s].total_cin += l - 4;
886 sess_local[s].cin += l - 4;
887
888 session[s].pin++;
889 eth_tx += l - 4;
890
891 STAT(tun_tx_packets);
892 INC_STAT(tun_tx_bytes, l - 4);
893 }
894
895 // process IPv6 packet received
896 //
897 // This MUST be called with at least 4 byte behind 'p'.
898 // (i.e. this routine writes to p[-4]).
899 void processipv6in(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
900 {
901 struct in6_addr ip;
902 in_addr_t ipv4;
903
904 CSTAT(processipv6in);
905
906 LOG_HEX(5, "IPv6", p, l);
907
908 ip = *(struct in6_addr *) (p + 8);
909 ipv4 = ntohl(*(uint32_t *)(p + 16));
910
911 if (l > MAXETHER)
912 {
913 LOG(1, s, t, "IP packet too long %d\n", l);
914 STAT(tunnel_rx_errors);
915 return ;
916 }
917
918 // no spoof
919 if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
920 {
921 char str[INET6_ADDRSTRLEN];
922 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
923 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
924 return;
925 }
926
927 // Check if it's a Router Solicition message.
928 if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
929 *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
930 *(uint32_t *)(p + 34) == 0 &&
931 *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
932 LOG(3, s, t, "Got IPv6 RS\n");
933 send_ipv6_ra(t, s, &ip);
934 return;
935 }
936
937 // Add on the tun header
938 p -= 4;
939 *(uint32_t *)p = htonl(PKTIPV6);
940 l += 4;
941
942 // Are we throttled and a slave?
943 if (session[s].tbf_in && !config->cluster_iam_master) {
944 // Pass it to the master for handling.
945 master_throttle_packet(session[s].tbf_in, p, l);
946 return;
947 }
948
949 // Are we throttled and a master?? actually handle the throttled
950 // packets.
951 if (session[s].tbf_in && config->cluster_iam_master) {
952 tbf_queue_packet(session[s].tbf_in, p, l);
953 return;
954 }
955
956 // send to ethernet
957 if (tun_write(p, l) < 0)
958 {
959 STAT(tun_tx_errors);
960 LOG(0, s, t, "Error writing %d bytes to TUN device: %s" " (tunfd=%d, p=%p)\n",
961 l, strerror(errno), tunfd, p);
962 }
963
964 if (session[s].snoop_ip && session[s].snoop_port)
965 {
966 // Snooping this session
967 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
968 }
969
970 session[s].cin += l - 4;
971 session[s].total_cin += l - 4;
972 sess_local[s].cin += l - 4;
973
974 session[s].pin++;
975 eth_tx += l - 4;
976
977 STAT(tun_tx_packets);
978 INC_STAT(tun_tx_bytes, l - 4);
979 }
980
981 //
982 // Helper routine for the TBF filters.
983 // Used to send queued data in from the user.
984 //
985 void send_ipin(sessionidt s, uint8_t *buf, int len)
986 {
987 LOG_HEX(5, "IP in throttled", buf, len);
988
989 if (write(tunfd, buf, len) < 0)
990 {
991 STAT(tun_tx_errors);
992 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
993 len, strerror(errno), tunfd, buf);
994
995 return;
996 }
997
998 if (session[s].snoop_ip && session[s].snoop_port)
999 {
1000 // Snooping this session
1001 snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
1002 }
1003
1004 // Increment packet counters
1005 session[s].cin += len - 4;
1006 session[s].total_cin += len - 4;
1007 sess_local[s].cin += len - 4;
1008
1009 session[s].pin++;
1010 eth_tx += len - 4;
1011
1012 STAT(tun_tx_packets);
1013 INC_STAT(tun_tx_bytes, len - 4);
1014 }
1015
1016
1017 // Process CCP messages
1018 void processccp(tunnelidt t, sessionidt s, uint8_t *p, uint16_t l)
1019 {
1020 uint8_t b[MAXCONTROL];
1021 uint8_t *q;
1022
1023 CSTAT(processccp);
1024
1025 LOG_HEX(5, "CCP", p, l);
1026 switch (l > 1 ? *p : 0)
1027 {
1028 case ConfigAck:
1029 session[s].flags |= SF_CCP_ACKED;
1030 return;
1031
1032 case ConfigReq:
1033 if (l < 6) // accept no compression
1034 {
1035 *p = ConfigAck;
1036 break;
1037 }
1038
1039 // compression requested--reject
1040 *p = ConfigRej;
1041
1042 // send CCP request for no compression for our end if not negotiated
1043 if (!(session[s].flags & SF_CCP_ACKED))
1044 initccp(t, s);
1045
1046 break;
1047
1048 case TerminateReq:
1049 *p = TerminateAck;
1050 break;
1051
1052 default:
1053 if (l > 1)
1054 LOG(1, s, t, "Unexpected CCP request code %d\n", *p);
1055 else
1056 LOG(1, s, t, "Short CCP packet\n");
1057
1058 STAT(tunnel_rx_errors);
1059 return;
1060 }
1061
1062 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
1063 return;
1064
1065 tunnelsend(b, l + (q - b), t); // send it
1066 }
1067
1068 // send a CHAP PP packet
1069 void sendchap(tunnelidt t, sessionidt s)
1070 {
1071 uint8_t b[MAXCONTROL];
1072 uint16_t r = session[s].radius;
1073 uint8_t *q;
1074
1075 CSTAT(sendchap);
1076
1077 if (!r)
1078 {
1079 LOG(1, s, t, "No RADIUS to send challenge\n");
1080 STAT(tunnel_tx_errors);
1081 return;
1082 }
1083
1084 LOG(1, s, t, "Send CHAP challenge\n");
1085
1086 // new challenge
1087 random_data(radius[r].auth, sizeof(radius[r].auth));
1088 radius[r].chap = 1; // CHAP not PAP
1089 radius[r].id++;
1090 if (radius[r].state != RADIUSCHAP)
1091 radius[r].try = 0;
1092
1093 radius[r].state = RADIUSCHAP;
1094 radius[r].retry = backoff(radius[r].try++);
1095 if (radius[r].try > 5)
1096 {
1097 sessionshutdown(s, "Timeout CHAP");
1098 STAT(tunnel_tx_errors);
1099 return ;
1100 }
1101 q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
1102 if (!q) return;
1103
1104 *q = 1; // challenge
1105 q[1] = radius[r].id; // ID
1106 q[4] = 16; // length
1107 memcpy(q + 5, radius[r].auth, 16); // challenge
1108 strcpy(q + 21, hostname); // our name
1109 *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1110 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1111 }
1112
1113 // fill in a L2TP message with a PPP frame,
1114 // copies existing PPP message and changes magic number if seen
1115 // returns start of PPP frame
1116 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, tunnelidt t, sessionidt s, uint16_t mtype)
1117 {
1118 if (size < 12) // Need more space than this!!
1119 {
1120 static int backtrace_count = 0;
1121 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1122 log_backtrace(backtrace_count, 5)
1123 return NULL;
1124 }
1125
1126 *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1127 *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1128 *(uint16_t *) (b + 4) = htons(session[s].far); // session
1129 b += 6;
1130 if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
1131 {
1132 *(uint16_t *) b = htons(0xFF03); // HDLC header
1133 b += 2;
1134 }
1135 if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
1136 *b++ = mtype;
1137 else
1138 {
1139 *(uint16_t *) b = htons(mtype);
1140 b += 2;
1141 }
1142
1143 if (l + 12 > size)
1144 {
1145 static int backtrace_count = 0;
1146 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1147 log_backtrace(backtrace_count, 5)
1148 return NULL;
1149 }
1150
1151 if (p && l)
1152 memcpy(b, p, l);
1153
1154 return b;
1155 }
1156
1157 // Send initial LCP ConfigReq for PAP, set magic no.
1158 void initlcp(tunnelidt t, sessionidt s)
1159 {
1160 char b[500], *q;
1161
1162 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
1163 return;
1164
1165 LOG(4, s, t, "Sending LCP ConfigReq for PAP\n");
1166 *q = ConfigReq;
1167 *(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID
1168 *(uint16_t *)(q + 2) = htons(14); // Length
1169 *(uint8_t *)(q + 4) = 5;
1170 *(uint8_t *)(q + 5) = 6;
1171 *(uint32_t *)(q + 6) = htonl(session[s].magic);
1172 *(uint8_t *)(q + 10) = 3;
1173 *(uint8_t *)(q + 11) = 4;
1174 *(uint16_t *)(q + 12) = htons(PPPPAP); // PAP
1175
1176 LOG_HEX(5, "PPPLCP", q, 14);
1177 tunnelsend(b, (q - b) + 14, t);
1178 }
1179
1180 // Send CCP request for no compression
1181 static void initccp(tunnelidt t, sessionidt s)
1182 {
1183 char b[500], *q;
1184
1185 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
1186 return;
1187
1188 LOG(4, s, t, "Sending CCP ConfigReq for no compression\n");
1189 *q = ConfigReq;
1190 *(uint8_t *)(q + 1) = (time_now % 255) + 1; // ID
1191 *(uint16_t *)(q + 2) = htons(4); // Length
1192
1193 LOG_HEX(5, "PPPCCP", q, 4);
1194 tunnelsend(b, (q - b) + 4 , t);
1195 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"