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disallow "fragments" on rules with layer 4 matches
[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.33 2004/11/29 02:17:18 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 u32 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, u8 *p, u16 l)
30 {
31 char user[129];
32 char pass[129];
33 u16 hl;
34
35 CSTAT(call_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(*(u16 *) (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 u8 *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 u8 b[MAXCONTROL];
76 u8 id = p[1];
77 u8 *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 *(u16 *) (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 u16 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, u8 *p, u16 l)
131 {
132 u16 r;
133 u16 hl;
134
135 CSTAT(call_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
143 // FIXME: Need to drop the session here.
144
145 STAT(tunnel_rx_errors);
146 return;
147 }
148
149 if (l < 4)
150 {
151 LOG(1, s, t, "Short CHAP %u bytes\n", l);
152 STAT(tunnel_rx_errors);
153 return ;
154 }
155
156 if ((hl = ntohs(*(u16 *) (p + 2))) > l)
157 {
158 LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
159 STAT(tunnel_rx_errors);
160 return ;
161 }
162 l = hl;
163
164 if (*p != 2)
165 {
166 LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
167 STAT(tunnel_rx_errors);
168 return;
169 }
170 if (p[1] != radius[r].id)
171 {
172 LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
173 STAT(tunnel_rx_errors);
174 return ;
175 }
176
177 if (l < 5 || p[4] != 16)
178 {
179 LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
180 STAT(tunnel_rx_errors);
181 return ;
182 }
183
184 l -= 5;
185 p += 5;
186 if (l < 16 || l - 16 >= sizeof(session[s].user))
187 {
188 LOG(1, s, t, "CHAP user too long %d\n", l - 16);
189 STAT(tunnel_rx_errors);
190 return ;
191 }
192
193 // Run PRE_AUTH plugins
194 {
195 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
196
197 packet.password = calloc(17, 1);
198 memcpy(packet.password, p, 16);
199
200 p += 16;
201 l -= 16;
202
203 packet.username = calloc(l + 1, 1);
204 memcpy(packet.username, p, l);
205
206 run_plugins(PLUGIN_PRE_AUTH, &packet);
207 if (!packet.continue_auth)
208 {
209 LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
210 if (packet.username) free(packet.username);
211 if (packet.password) free(packet.password);
212 return;
213 }
214
215 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
216 memcpy(radius[r].pass, packet.password, 16);
217
218 free(packet.username);
219 free(packet.password);
220 }
221
222 radius[r].chap = 1;
223 LOG(3, s, t, "CHAP login %s\n", session[s].user);
224 radiussend(r, RADIUSAUTH);
225 }
226
227 static char *ppp_lcp_types[] = {
228 NULL,
229 "ConfigReq",
230 "ConfigAck",
231 "ConfigNak",
232 "ConfigRej",
233 "TerminateReq",
234 "TerminateAck",
235 "CodeRej",
236 "ProtocolRej",
237 "EchoReq",
238 "EchoReply",
239 "DiscardRequest",
240 "IdentRequest",
241 };
242
243 static void dumplcp(u8 *p, int l)
244 {
245 int x = l - 4;
246 u8 *o = (p + 4);
247
248 LOG_HEX(5, "PPP LCP Packet", p, l);
249 LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
250 LOG(4, 0, 0, "Length: %d\n", l);
251 if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
252 return;
253
254 while (x > 2)
255 {
256 int type = o[0];
257 int length = o[1];
258 if (length < 2)
259 {
260 LOG(4, 0, 0, " Option length is %d...\n", length);
261 break;
262 }
263 if (type == 0)
264 {
265 LOG(4, 0, 0, " Option type is 0...\n");
266 x -= length;
267 o += length;
268 continue;
269 }
270 switch (type)
271 {
272 case 1: // Maximum-Receive-Unit
273 if (length == 4)
274 LOG(4, 0, 0, " %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
275 else
276 LOG(4, 0, 0, " %s odd length %d\n", lcp_types[type], length);
277 break;
278 case 2: // Async-Control-Character-Map
279 if (length == 6)
280 {
281 u32 asyncmap = ntohl(*(u32 *)(o + 2));
282 LOG(4, 0, 0, " %s %x\n", lcp_types[type], asyncmap);
283 }
284 else
285 LOG(4, 0, 0, " %s odd length %d\n", lcp_types[type], length);
286 break;
287 case 3: // Authentication-Protocol
288 if (length == 4)
289 {
290 int proto = ntohs(*(u16 *)(o + 2));
291 LOG(4, 0, 0, " %s 0x%x (%s)\n", lcp_types[type], proto,
292 proto == PPPCHAP ? "CHAP" :
293 proto == PPPPAP ? "PAP" : "UNKNOWN");
294 }
295 else
296 LOG(4, 0, 0, " %s odd length %d\n", lcp_types[type], length);
297 break;
298 case 4: // Quality-Protocol
299 {
300 u32 qp = ntohl(*(u32 *)(o + 2));
301 LOG(4, 0, 0, " %s %x\n", lcp_types[type], qp);
302 }
303 break;
304 case 5: // Magic-Number
305 if (length == 6)
306 {
307 u32 magicno = ntohl(*(u32 *)(o + 2));
308 LOG(4, 0, 0, " %s %x\n", lcp_types[type], magicno);
309 }
310 else
311 LOG(4, 0, 0, " %s odd length %d\n", lcp_types[type], length);
312 break;
313 case 7: // Protocol-Field-Compression
314 case 8: // Address-And-Control-Field-Compression
315 LOG(4, 0, 0, " %s\n", lcp_types[type]);
316 break;
317 default:
318 LOG(2, 0, 0, " Unknown PPP LCP Option type %d\n", type);
319 break;
320 }
321 x -= length;
322 o += length;
323 }
324 }
325
326 // Process LCP messages
327 void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
328 {
329 u8 b[MAXCONTROL];
330 u8 *q = NULL;
331 u32 magicno = 0;
332 u16 hl;
333
334 CSTAT(call_processlcp);
335
336 LOG_HEX(5, "LCP", p, l);
337 if (l < 4)
338 {
339 LOG(1, s, t, "Short LCP %d bytes\n", l);
340 STAT(tunnel_rx_errors);
341 return ;
342 }
343
344 if ((hl = ntohs(*(u16 *) (p + 2))) > l)
345 {
346 LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
347 STAT(tunnel_rx_errors);
348 return ;
349 }
350 l = hl;
351
352 if (*p == ConfigAck)
353 {
354 LOG(3, s, t, "LCP: Discarding ConfigAck\n");
355 session[s].flags |= SF_LCP_ACKED;
356 }
357 else if (*p == ConfigReq)
358 {
359 int x = l - 4;
360 u8 *o = (p + 4);
361 u8 response = 0;
362
363 LOG(3, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
364 if (config->debug > 3) dumplcp(p, l);
365
366 while (x > 2)
367 {
368 int type = o[0];
369 int length = o[1];
370 if (length == 0 || type == 0 || x < length) break;
371 switch (type)
372 {
373 case 1: // Maximum-Receive-Unit
374 session[s].mru = ntohs(*(u16 *)(o + 2));
375 break;
376
377 case 2: // Async-Control-Character-Map
378 if (!ntohl(*(u32 *)(o + 2))) // all bits zero is OK
379 break;
380
381 if (response && response != ConfigNak) // rej already queued
382 break;
383
384 LOG(2, s, t, " Remote requesting asyncmap. Rejecting.\n");
385 if (!response)
386 {
387 q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
388 if (!q) break;
389 response = *q++ = ConfigNak;
390 }
391
392 if ((q - b + 11) > sizeof(b))
393 {
394 LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n");
395 break;
396 }
397
398 *q++ = type;
399 *q++ = 6;
400 memset(q, 0, 4); // asyncmap 0
401 q += 4;
402 break;
403
404 case 3: // Authentication-Protocol
405 {
406 int proto = ntohs(*(u16 *)(o + 2));
407 char proto_name[] = "0x0000";
408 if (proto == PPPPAP)
409 break;
410
411 if (response && response != ConfigNak) // rej already queued
412 break;
413
414 if (proto == PPPCHAP)
415 strcpy(proto_name, "CHAP");
416 else
417 sprintf(proto_name, "%#4.4x", proto);
418
419 LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
420
421 if (!response)
422 {
423 q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
424 if (!q) break;
425 response = *q++ = ConfigNak;
426 }
427
428 if ((q - b + length) > sizeof(b))
429 {
430 LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
431 break;
432 }
433
434 memcpy(q, o, length);
435 *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
436 q += length;
437 }
438 break;
439
440 case 5: // Magic-Number
441 magicno = ntohl(*(u32 *)(o + 2));
442 break;
443
444 case 4: // Quality-Protocol
445 case 7: // Protocol-Field-Compression
446 case 8: // Address-And-Control-Field-Compression
447 break;
448
449 default: // Reject any unknown options
450 LOG(2, s, t, " Rejecting PPP LCP Option type %d\n", type);
451 if (!response || response != ConfigRej) // drop nak in favour of rej
452 {
453 q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
454 if (!q) return;
455 response = *q++ = ConfigRej;
456 }
457
458 if ((q - b + length) > sizeof(b))
459 {
460 LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
461 break;
462 }
463
464 memcpy(q, o, length);
465 q += length;
466 }
467 x -= length;
468 o += length;
469 }
470
471 if (!response)
472 {
473 // Send back a ConfigAck
474 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
475 if (!q) return;
476 response = *q = ConfigAck;
477 }
478
479 LOG(3, s, t, "Sending %s\n", ppp_lcp_types[response]);
480 tunnelsend(b, l + (q - b), t);
481
482 if (!(session[s].flags & SF_LCP_ACKED))
483 initlcp(t, s);
484 }
485 else if (*p == ConfigNak)
486 {
487 LOG(1, s, t, "Remote end sent a ConfigNak. Ignoring\n");
488 if (config->debug > 3) dumplcp(p, l);
489 return ;
490 }
491 else if (*p == TerminateReq)
492 {
493 LOG(3, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
494 *p = TerminateAck; // close
495 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
496 if (!q) return;
497 tunnelsend(b, l + (q - b), t); // send it
498 sessionshutdown(s, "Remote end closed connection.");
499 }
500 else if (*p == TerminateAck)
501 {
502 sessionshutdown(s, "Connection closed.");
503 }
504 else if (*p == EchoReq)
505 {
506 LOG(5, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
507 *p = EchoReply; // reply
508 *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
509 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
510 if (!q) return;
511 tunnelsend(b, l + (q - b), t); // send it
512 }
513 else if (*p == EchoReply)
514 {
515 // Ignore it, last_packet time is set earlier than this.
516 }
517 else if (*p == IdentRequest)
518 {
519 *p = CodeRej;
520 if (l > MAXCONTROL)
521 {
522 LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
523 l = 1400;
524 }
525 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
526 if (!q) return;
527 LOG_HEX(5, "LCPIdentRej", q, l + 4);
528 tunnelsend(b, 12 + 4 + l, t);
529 }
530 else
531 {
532 LOG(1, s, t, "Unexpected LCP code %d\n", *p);
533 STAT(tunnel_rx_errors);
534 return ;
535 }
536 }
537
538 // find a PPP option, returns point to option, or 0 if not found
539 static u8 *findppp(u8 *b, u8 mtype)
540 {
541 u16 l = ntohs(*(u16 *) (b + 2));
542 if (l < 4)
543 return 0;
544 b += 4;
545 l -= 4;
546 while (l)
547 {
548 if (l < b[1] || !b[1])
549 return 0; // faulty
550 if (*b == mtype)
551 return b;
552 l -= b[1];
553 b += b[1];
554 }
555 return 0;
556 }
557
558 // Process IPCP messages
559 void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
560 {
561 u16 hl;
562
563 CSTAT(call_processipcp);
564
565 LOG_HEX(5, "IPCP", p, l);
566 if (l < 5)
567 {
568 LOG(1, s, t, "Short IPCP %d bytes\n", l);
569 STAT(tunnel_rx_errors);
570 return ;
571 }
572
573 if ((hl = ntohs(*(u16 *) (p + 2))) > l)
574 {
575 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
576 STAT(tunnel_rx_errors);
577 return ;
578 }
579 l = hl;
580
581 if (*p == ConfigAck)
582 {
583 // happy with our IPCP
584 u16 r = session[s].radius;
585 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
586 {
587 if (!r)
588 r = radiusnew(s);
589 if (r)
590 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
591 }
592 session[s].flags |= SF_IPCP_ACKED;
593
594 LOG(3, s, t, "IPCP Acked, session is now active\n");
595
596 // clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
597 session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
598
599 return;
600 }
601 if (*p != ConfigReq)
602 {
603 LOG(1, s, t, "Unexpected IPCP code %d\n", *p);
604 STAT(tunnel_rx_errors);
605 return ;
606 }
607 LOG(4, s, t, "IPCP ConfigReq received\n");
608
609 if (!session[s].ip)
610 {
611 LOG(3, s, t, "Waiting on radius reply\n");
612 return; // have to wait on RADIUS reply
613 }
614 // form a config reply quoting the IP in the session
615 {
616 u8 b[MAXCONTROL];
617 u8 *i,
618 *q;
619
620 q = p + 4;
621 i = p + l;
622 while (q < i && q[1])
623 {
624 if (*q != 0x81 && *q != 0x83 && *q != 3)
625 break;
626 q += q[1];
627 }
628 if (q < i)
629 {
630 // reject
631 u16 n = 4;
632 i = p + l;
633 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
634 return;
635
636 *q = ConfigRej;
637 p += 4;
638 while (p < i && p[1])
639 {
640 if (*p != 0x81 && *p != 0x83 && *p != 3)
641 {
642 LOG(2, s, t, "IPCP reject %d\n", *p);
643 memcpy(q + n, p, p[1]);
644 n += p[1];
645 }
646 p += p[1];
647 }
648 *(u16 *) (q + 2) = htons(n);
649 LOG(4, s, t, "Sending ConfigRej\n");
650 tunnelsend(b, n + (q - b), t); // send it
651 }
652 else
653 {
654 LOG(4, s, t, "Sending ConfigAck\n");
655 *p = ConfigAck;
656 if ((i = findppp(p, 0x81))) // Primary DNS address
657 {
658 if (*(u32 *) (i + 2) != htonl(session[s].dns1))
659 {
660 *(u32 *) (i + 2) = htonl(session[s].dns1);
661 *p = ConfigNak;
662 LOG(5, s, t, " DNS1 = %s\n", fmtaddr(session[s].dns1, 0));
663 }
664 }
665 if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
666 {
667 if (*(u32 *) (i + 2) != htonl(session[s].dns2))
668 {
669 *(u32 *) (i + 2) = htonl(session[s].dns2);
670 *p = ConfigNak;
671 LOG(5, s, t, " DNS2 = %s\n", fmtaddr(session[s].dns2, 0));
672 }
673 }
674 i = findppp(p, 3); // IP address
675 if (!i || i[1] != 6)
676 {
677 LOG(1, s, t, "No IP in IPCP request\n");
678 STAT(tunnel_rx_errors);
679 return ;
680 }
681 if (*(u32 *) (i + 2) != htonl(session[s].ip))
682 {
683 *(u32 *) (i + 2) = htonl(session[s].ip);
684 *p = ConfigNak;
685 LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
686 fmtaddr(htonl(session[s].ip), 0));
687 }
688 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
689 return;
690
691 tunnelsend(b, l + (q - b), t); // send it
692 }
693 }
694 }
695
696 // process IP packet received
697 //
698 // This MUST be called with at least 4 byte behind 'p'.
699 // (i.e. this routine writes to p[-4]).
700 void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
701 {
702 ipt ip;
703
704 CSTAT(call_processipin);
705
706 LOG_HEX(5, "IP", p, l);
707
708 ip = ntohl(*(u32 *)(p + 12));
709
710 if (l > MAXETHER)
711 {
712 LOG(1, s, t, "IP packet too long %d\n", l);
713 STAT(tunnel_rx_errors);
714 return ;
715 }
716
717 // no spoof (do sessionbyip to handled statically routed subnets)
718 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
719 {
720 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
721 return;
722 }
723
724 // run access-list if any
725 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
726 return;
727
728 // Add on the tun header
729 p -= 4;
730 *(u32 *)p = htonl(0x00000800);
731 l += 4;
732
733 if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
734 master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
735 return;
736 }
737
738 if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
739 tbf_queue_packet(session[s].tbf_in, p, l);
740 return;
741 }
742
743 // send to ethernet
744 if (tun_write(p, l) < 0)
745 {
746 STAT(tun_tx_errors);
747 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
748 l, strerror(errno), tunfd, p);
749
750 return;
751 }
752
753 if (session[s].snoop_ip && session[s].snoop_port)
754 {
755 // Snooping this session
756 snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
757 }
758
759 session[s].cin += l - 4;
760 session[s].total_cin += l - 4;
761 sess_count[s].cin += l - 4;
762
763 session[s].pin++;
764 eth_tx += l - 4;
765
766 STAT(tun_tx_packets);
767 INC_STAT(tun_tx_bytes, l - 4);
768 }
769
770 //
771 // Helper routine for the TBF filters.
772 // Used to send queued data in from the user.
773 //
774 void send_ipin(sessionidt s, u8 *buf, int len)
775 {
776 LOG_HEX(5, "IP in throttled", buf, len);
777
778 if (write(tunfd, buf, len) < 0)
779 {
780 STAT(tun_tx_errors);
781 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
782 len, strerror(errno), tunfd, buf);
783
784 return;
785 }
786
787 if (session[s].snoop_ip && session[s].snoop_port)
788 {
789 // Snooping this session
790 snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
791 }
792
793 // Increment packet counters
794 session[s].cin += len - 4;
795 session[s].total_cin += len - 4;
796 sess_count[s].cin += len - 4;
797
798 session[s].pin++;
799 eth_tx += len - 4;
800
801 STAT(tun_tx_packets);
802 INC_STAT(tun_tx_bytes, len - 4);
803 }
804
805
806 // Process CCP messages
807 void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l)
808 {
809 u8 b[MAXCONTROL];
810 u8 *q;
811
812 CSTAT(call_processccp);
813
814 LOG_HEX(5, "CCP", p, l);
815 switch (l > 1 ? *p : 0)
816 {
817 case ConfigAck:
818 session[s].flags |= SF_CCP_ACKED;
819 return;
820
821 case ConfigReq:
822 if (l < 6) // accept no compression
823 {
824 *p = ConfigAck;
825 break;
826 }
827
828 // compression requested--reject
829 *p = ConfigRej;
830
831 // send CCP request for no compression for our end if not negotiated
832 if (!(session[s].flags & SF_CCP_ACKED))
833 initccp(t, s);
834
835 break;
836
837 case TerminateReq:
838 *p = TerminateAck;
839 break;
840
841 default:
842 if (l > 1)
843 LOG(1, s, t, "Unexpected CCP request code %d\n", *p);
844 else
845 LOG(1, s, t, "Short CCP packet\n");
846
847 STAT(tunnel_rx_errors);
848 return;
849 }
850
851 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
852 return;
853
854 tunnelsend(b, l + (q - b), t); // send it
855 }
856
857 // send a CHAP PP packet
858 void sendchap(tunnelidt t, sessionidt s)
859 {
860 u8 b[MAXCONTROL];
861 u16 r = session[s].radius;
862 u8 *q;
863
864 CSTAT(call_sendchap);
865
866 if (!r)
867 {
868 LOG(1, s, t, "No RADIUS to send challenge\n");
869 STAT(tunnel_tx_errors);
870 return ;
871 }
872 LOG(1, s, t, "Send CHAP challenge\n");
873 {
874 // new challenge
875 int n;
876 for (n = 0; n < 15; n++)
877 radius[r].auth[n] = rand();
878 }
879 radius[r].chap = 1; // CHAP not PAP
880 radius[r].id++;
881 if (radius[r].state != RADIUSCHAP)
882 radius[r].try = 0;
883 radius[r].state = RADIUSCHAP;
884 radius[r].retry = backoff(radius[r].try++);
885 if (radius[r].try > 5)
886 {
887 sessionshutdown(s, "Timeout CHAP");
888 STAT(tunnel_tx_errors);
889 return ;
890 }
891 q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
892 if (!q) return;
893
894 *q = 1; // challenge
895 q[1] = radius[r].id; // ID
896 q[4] = 16; // length
897 memcpy(q + 5, radius[r].auth, 16); // challenge
898 strcpy(q + 21, hostname); // our name
899 *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
900 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
901 }
902
903 // fill in a L2TP message with a PPP frame,
904 // copies existing PPP message and changes magic number if seen
905 // returns start of PPP frame
906 u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
907 {
908 if (size < 12) // Need more space than this!!
909 {
910 static int backtrace_count = 0;
911 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
912 log_backtrace(backtrace_count, 5)
913 return NULL;
914 }
915
916 *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
917 *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
918 *(u16 *) (b + 4) = htons(session[s].far); // session
919 b += 6;
920 if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
921 {
922 *(u16 *) b = htons(0xFF03); // HDLC header
923 b += 2;
924 }
925 if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
926 *b++ = mtype;
927 else
928 {
929 *(u16 *) b = htons(mtype);
930 b += 2;
931 }
932
933 if (l + 12 > size)
934 {
935 static int backtrace_count = 0;
936 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
937 log_backtrace(backtrace_count, 5)
938 return NULL;
939 }
940
941 if (p && l)
942 memcpy(b, p, l);
943
944 return b;
945 }
946
947 // Send initial LCP ConfigReq for PAP, set magic no.
948 void initlcp(tunnelidt t, sessionidt s)
949 {
950 char b[500], *q;
951
952 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
953 return;
954
955 LOG(4, s, t, "Sending LCP ConfigReq for PAP\n");
956 *q = ConfigReq;
957 *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
958 *(u16 *)(q + 2) = htons(14); // Length
959 *(u8 *)(q + 4) = 5;
960 *(u8 *)(q + 5) = 6;
961 *(u32 *)(q + 6) = htonl(session[s].magic);
962 *(u8 *)(q + 10) = 3;
963 *(u8 *)(q + 11) = 4;
964 *(u16 *)(q + 12) = htons(PPPPAP); // PAP
965
966 LOG_HEX(5, "PPPLCP", q, 14);
967 tunnelsend(b, (q - b) + 14, t);
968 }
969
970 // Send CCP request for no compression
971 static void initccp(tunnelidt t, sessionidt s)
972 {
973 char b[500], *q;
974
975 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
976 return;
977
978 LOG(4, s, t, "Sending CCP ConfigReq for no compression\n");
979 *q = ConfigReq;
980 *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
981 *(u16 *)(q + 2) = htons(4); // Length
982
983 LOG_HEX(5, "PPPCCP", q, 4);
984 tunnelsend(b, (q - b) + 4 , t);
985 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"