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[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.37 2004-11-30 01:35:19 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
371 if (length == 0 || type == 0 || x < length) break;
372 switch (type)
373 {
374 case 1: // Maximum-Receive-Unit
375 session[s].mru = ntohs(*(u16 *)(o + 2));
376 break;
377
378 case 2: // Async-Control-Character-Map
379 if (!ntohl(*(u32 *)(o + 2))) // all bits zero is OK
380 break;
381
382 if (response && *response != ConfigNak) // rej already queued
383 break;
384
385 LOG(2, s, t, " Remote requesting asyncmap. Rejecting.\n");
386 if (!response)
387 {
388 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
389 if (!q) break;
390 *q = ConfigNak;
391 q += 4;
392 }
393
394 if ((q - b + 11) > sizeof(b))
395 {
396 LOG(2, s, t, "LCP overflow for asyncmap ConfigNak.\n");
397 break;
398 }
399
400 *q++ = type;
401 *q++ = 6;
402 memset(q, 0, 4); // asyncmap 0
403 q += 4;
404 *((u16 *) (response + 2)) = q - response; // LCP header length
405 break;
406
407 case 3: // Authentication-Protocol
408 {
409 int proto = ntohs(*(u16 *)(o + 2));
410 char proto_name[] = "0x0000";
411 if (proto == PPPPAP)
412 break;
413
414 if (response && *response != ConfigNak) // rej already queued
415 break;
416
417 if (proto == PPPCHAP)
418 strcpy(proto_name, "CHAP");
419 else
420 sprintf(proto_name, "%#4.4x", proto);
421
422 LOG(2, s, t, " Remote requesting %s authentication. Rejecting.\n", proto_name);
423
424 if (!response)
425 {
426 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
427 if (!q) break;
428 *q = ConfigNak;
429 q += 4;
430 }
431
432 if ((q - b + length) > sizeof(b))
433 {
434 LOG(2, s, t, "LCP overflow for %s ConfigNak.\n", proto_name);
435 break;
436 }
437
438 memcpy(q, o, length);
439 *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
440 q += length;
441 *((u16 *) (response + 2)) = q - response;
442 }
443 break;
444
445 case 5: // Magic-Number
446 magicno = ntohl(*(u32 *)(o + 2));
447 break;
448
449 case 4: // Quality-Protocol
450 case 7: // Protocol-Field-Compression
451 case 8: // Address-And-Control-Field-Compression
452 break;
453
454 default: // Reject any unknown options
455 LOG(2, s, t, " Rejecting PPP LCP Option type %d\n", type);
456 if (!response || *response != ConfigRej) // drop nak in favour of rej
457 {
458 q = response = makeppp(b, sizeof(b), p, 2, t, s, PPPLCP);
459 if (!q) break;
460 *q = ConfigRej;
461 q += 4;
462 }
463
464 if ((q - b + length) > sizeof(b))
465 {
466 LOG(2, s, t, "LCP overflow for ConfigRej (type=%d).\n", type);
467 break;
468 }
469
470 memcpy(q, o, length);
471 q += length;
472 *((u16 *) (response + 2)) = q - response; // LCP header length
473 }
474 x -= length;
475 o += length;
476 }
477
478 if (!response)
479 {
480 // Send back a ConfigAck
481 q = response = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
482 if (!q) return;
483 *q = ConfigAck;
484 }
485
486 LOG(3, s, t, "Sending %s\n", ppp_lcp_types[*response]);
487 tunnelsend(b, l + (q - b), t);
488
489 if (!(session[s].flags & SF_LCP_ACKED))
490 initlcp(t, s);
491 }
492 else if (*p == ConfigNak)
493 {
494 LOG(1, s, t, "Remote end sent a ConfigNak. Ignoring\n");
495 if (config->debug > 3) dumplcp(p, l);
496 return ;
497 }
498 else if (*p == TerminateReq)
499 {
500 LOG(3, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
501 *p = TerminateAck; // close
502 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
503 if (!q) return;
504 tunnelsend(b, l + (q - b), t); // send it
505 sessionshutdown(s, "Remote end closed connection.");
506 }
507 else if (*p == TerminateAck)
508 {
509 sessionshutdown(s, "Connection closed.");
510 }
511 else if (*p == EchoReq)
512 {
513 LOG(5, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
514 *p = EchoReply; // reply
515 *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
516 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
517 if (!q) return;
518 tunnelsend(b, l + (q - b), t); // send it
519 }
520 else if (*p == EchoReply)
521 {
522 // Ignore it, last_packet time is set earlier than this.
523 }
524 else if (*p == IdentRequest)
525 {
526 *p = CodeRej;
527 if (l > MAXCONTROL)
528 {
529 LOG(1, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
530 l = 1400;
531 }
532 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
533 if (!q) return;
534 LOG_HEX(5, "LCPIdentRej", q, l + 4);
535 tunnelsend(b, 12 + 4 + l, t);
536 }
537 else
538 {
539 LOG(1, s, t, "Unexpected LCP code %d\n", *p);
540 STAT(tunnel_rx_errors);
541 return ;
542 }
543 }
544
545 // find a PPP option, returns point to option, or 0 if not found
546 static u8 *findppp(u8 *b, u8 mtype)
547 {
548 u16 l = ntohs(*(u16 *) (b + 2));
549 if (l < 4)
550 return 0;
551 b += 4;
552 l -= 4;
553 while (l)
554 {
555 if (l < b[1] || !b[1])
556 return 0; // faulty
557 if (*b == mtype)
558 return b;
559 l -= b[1];
560 b += b[1];
561 }
562 return 0;
563 }
564
565 // Process IPCP messages
566 void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
567 {
568 u16 hl;
569
570 CSTAT(call_processipcp);
571
572 LOG_HEX(5, "IPCP", p, l);
573 if (l < 5)
574 {
575 LOG(1, s, t, "Short IPCP %d bytes\n", l);
576 STAT(tunnel_rx_errors);
577 return ;
578 }
579
580 if ((hl = ntohs(*(u16 *) (p + 2))) > l)
581 {
582 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
583 STAT(tunnel_rx_errors);
584 return ;
585 }
586 l = hl;
587
588 if (*p == ConfigAck)
589 {
590 // happy with our IPCP
591 u16 r = session[s].radius;
592 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
593 {
594 if (!r)
595 r = radiusnew(s);
596 if (r)
597 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
598 }
599 session[s].flags |= SF_IPCP_ACKED;
600
601 LOG(3, s, t, "IPCP Acked, session is now active\n");
602
603 // clear LCP_ACKED/CCP_ACKED flag for possible fast renegotiaion for routers
604 session[s].flags &= ~(SF_LCP_ACKED|SF_CCP_ACKED);
605
606 return;
607 }
608 if (*p != ConfigReq)
609 {
610 LOG(1, s, t, "Unexpected IPCP code %d\n", *p);
611 STAT(tunnel_rx_errors);
612 return ;
613 }
614 LOG(4, s, t, "IPCP ConfigReq received\n");
615
616 if (!session[s].ip)
617 {
618 LOG(3, s, t, "Waiting on radius reply\n");
619 return; // have to wait on RADIUS reply
620 }
621 // form a config reply quoting the IP in the session
622 {
623 u8 b[MAXCONTROL];
624 u8 *i,
625 *q;
626
627 q = p + 4;
628 i = p + l;
629 while (q < i && q[1])
630 {
631 if (*q != 0x81 && *q != 0x83 && *q != 3)
632 break;
633 q += q[1];
634 }
635 if (q < i)
636 {
637 // reject
638 u16 n = 4;
639 i = p + l;
640 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
641 return;
642
643 *q = ConfigRej;
644 p += 4;
645 while (p < i && p[1])
646 {
647 if (*p != 0x81 && *p != 0x83 && *p != 3)
648 {
649 LOG(2, s, t, "IPCP reject %d\n", *p);
650 memcpy(q + n, p, p[1]);
651 n += p[1];
652 }
653 p += p[1];
654 }
655 *(u16 *) (q + 2) = htons(n);
656 LOG(4, s, t, "Sending ConfigRej\n");
657 tunnelsend(b, n + (q - b), t); // send it
658 }
659 else
660 {
661 LOG(4, s, t, "Sending ConfigAck\n");
662 *p = ConfigAck;
663 if ((i = findppp(p, 0x81))) // Primary DNS address
664 {
665 if (*(u32 *) (i + 2) != htonl(session[s].dns1))
666 {
667 *(u32 *) (i + 2) = htonl(session[s].dns1);
668 *p = ConfigNak;
669 LOG(5, s, t, " DNS1 = %s\n",
670 fmtaddr(htonl(session[s].dns1), 0));
671 }
672 }
673 if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
674 {
675 if (*(u32 *) (i + 2) != htonl(session[s].dns2))
676 {
677 *(u32 *) (i + 2) = htonl(session[s].dns2);
678 *p = ConfigNak;
679 LOG(5, s, t, " DNS2 = %s\n",
680 fmtaddr(htonl(session[s].dns2), 0));
681 }
682 }
683 i = findppp(p, 3); // IP address
684 if (!i || i[1] != 6)
685 {
686 LOG(1, s, t, "No IP in IPCP request\n");
687 STAT(tunnel_rx_errors);
688 return ;
689 }
690 if (*(u32 *) (i + 2) != htonl(session[s].ip))
691 {
692 *(u32 *) (i + 2) = htonl(session[s].ip);
693 *p = ConfigNak;
694 LOG(4, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
695 fmtaddr(htonl(session[s].ip), 0));
696 }
697 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
698 return;
699
700 tunnelsend(b, l + (q - b), t); // send it
701 }
702 }
703 }
704
705 // process IP packet received
706 //
707 // This MUST be called with at least 4 byte behind 'p'.
708 // (i.e. this routine writes to p[-4]).
709 void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
710 {
711 ipt ip;
712
713 CSTAT(call_processipin);
714
715 LOG_HEX(5, "IP", p, l);
716
717 ip = ntohl(*(u32 *)(p + 12));
718
719 if (l > MAXETHER)
720 {
721 LOG(1, s, t, "IP packet too long %d\n", l);
722 STAT(tunnel_rx_errors);
723 return ;
724 }
725
726 // no spoof (do sessionbyip to handled statically routed subnets)
727 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
728 {
729 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
730 return;
731 }
732
733 // run access-list if any
734 if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
735 return;
736
737 // Add on the tun header
738 p -= 4;
739 *(u32 *)p = htonl(0x00000800);
740 l += 4;
741
742 if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
743 master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
744 return;
745 }
746
747 if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
748 tbf_queue_packet(session[s].tbf_in, p, l);
749 return;
750 }
751
752 // send to ethernet
753 if (tun_write(p, l) < 0)
754 {
755 STAT(tun_tx_errors);
756 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
757 l, strerror(errno), tunfd, p);
758
759 return;
760 }
761
762 if (session[s].snoop_ip && session[s].snoop_port)
763 {
764 // Snooping this session
765 snoop_send_packet(p + 4, l - 4, session[s].snoop_ip, session[s].snoop_port);
766 }
767
768 session[s].cin += l - 4;
769 session[s].total_cin += l - 4;
770 sess_count[s].cin += l - 4;
771
772 session[s].pin++;
773 eth_tx += l - 4;
774
775 STAT(tun_tx_packets);
776 INC_STAT(tun_tx_bytes, l - 4);
777 }
778
779 //
780 // Helper routine for the TBF filters.
781 // Used to send queued data in from the user.
782 //
783 void send_ipin(sessionidt s, u8 *buf, int len)
784 {
785 LOG_HEX(5, "IP in throttled", buf, len);
786
787 if (write(tunfd, buf, len) < 0)
788 {
789 STAT(tun_tx_errors);
790 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
791 len, strerror(errno), tunfd, buf);
792
793 return;
794 }
795
796 if (session[s].snoop_ip && session[s].snoop_port)
797 {
798 // Snooping this session
799 snoop_send_packet(buf + 4, len - 4, session[s].snoop_ip, session[s].snoop_port);
800 }
801
802 // Increment packet counters
803 session[s].cin += len - 4;
804 session[s].total_cin += len - 4;
805 sess_count[s].cin += len - 4;
806
807 session[s].pin++;
808 eth_tx += len - 4;
809
810 STAT(tun_tx_packets);
811 INC_STAT(tun_tx_bytes, len - 4);
812 }
813
814
815 // Process CCP messages
816 void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l)
817 {
818 u8 b[MAXCONTROL];
819 u8 *q;
820
821 CSTAT(call_processccp);
822
823 LOG_HEX(5, "CCP", p, l);
824 switch (l > 1 ? *p : 0)
825 {
826 case ConfigAck:
827 session[s].flags |= SF_CCP_ACKED;
828 return;
829
830 case ConfigReq:
831 if (l < 6) // accept no compression
832 {
833 *p = ConfigAck;
834 break;
835 }
836
837 // compression requested--reject
838 *p = ConfigRej;
839
840 // send CCP request for no compression for our end if not negotiated
841 if (!(session[s].flags & SF_CCP_ACKED))
842 initccp(t, s);
843
844 break;
845
846 case TerminateReq:
847 *p = TerminateAck;
848 break;
849
850 default:
851 if (l > 1)
852 LOG(1, s, t, "Unexpected CCP request code %d\n", *p);
853 else
854 LOG(1, s, t, "Short CCP packet\n");
855
856 STAT(tunnel_rx_errors);
857 return;
858 }
859
860 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
861 return;
862
863 tunnelsend(b, l + (q - b), t); // send it
864 }
865
866 // send a CHAP PP packet
867 void sendchap(tunnelidt t, sessionidt s)
868 {
869 u8 b[MAXCONTROL];
870 u16 r = session[s].radius;
871 u8 *q;
872
873 CSTAT(call_sendchap);
874
875 if (!r)
876 {
877 LOG(1, s, t, "No RADIUS to send challenge\n");
878 STAT(tunnel_tx_errors);
879 return ;
880 }
881 LOG(1, s, t, "Send CHAP challenge\n");
882 {
883 // new challenge
884 int n;
885 for (n = 0; n < 15; n++)
886 radius[r].auth[n] = rand();
887 }
888 radius[r].chap = 1; // CHAP not PAP
889 radius[r].id++;
890 if (radius[r].state != RADIUSCHAP)
891 radius[r].try = 0;
892 radius[r].state = RADIUSCHAP;
893 radius[r].retry = backoff(radius[r].try++);
894 if (radius[r].try > 5)
895 {
896 sessionshutdown(s, "Timeout CHAP");
897 STAT(tunnel_tx_errors);
898 return ;
899 }
900 q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
901 if (!q) return;
902
903 *q = 1; // challenge
904 q[1] = radius[r].id; // ID
905 q[4] = 16; // length
906 memcpy(q + 5, radius[r].auth, 16); // challenge
907 strcpy(q + 21, hostname); // our name
908 *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
909 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
910 }
911
912 // fill in a L2TP message with a PPP frame,
913 // copies existing PPP message and changes magic number if seen
914 // returns start of PPP frame
915 u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
916 {
917 if (size < 12) // Need more space than this!!
918 {
919 static int backtrace_count = 0;
920 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
921 log_backtrace(backtrace_count, 5)
922 return NULL;
923 }
924
925 *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
926 *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
927 *(u16 *) (b + 4) = htons(session[s].far); // session
928 b += 6;
929 if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
930 {
931 *(u16 *) b = htons(0xFF03); // HDLC header
932 b += 2;
933 }
934 if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
935 *b++ = mtype;
936 else
937 {
938 *(u16 *) b = htons(mtype);
939 b += 2;
940 }
941
942 if (l + 12 > size)
943 {
944 static int backtrace_count = 0;
945 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
946 log_backtrace(backtrace_count, 5)
947 return NULL;
948 }
949
950 if (p && l)
951 memcpy(b, p, l);
952
953 return b;
954 }
955
956 // Send initial LCP ConfigReq for PAP, set magic no.
957 void initlcp(tunnelidt t, sessionidt s)
958 {
959 char b[500], *q;
960
961 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP)))
962 return;
963
964 LOG(4, s, t, "Sending LCP ConfigReq for PAP\n");
965 *q = ConfigReq;
966 *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
967 *(u16 *)(q + 2) = htons(14); // Length
968 *(u8 *)(q + 4) = 5;
969 *(u8 *)(q + 5) = 6;
970 *(u32 *)(q + 6) = htonl(session[s].magic);
971 *(u8 *)(q + 10) = 3;
972 *(u8 *)(q + 11) = 4;
973 *(u16 *)(q + 12) = htons(PPPPAP); // PAP
974
975 LOG_HEX(5, "PPPLCP", q, 14);
976 tunnelsend(b, (q - b) + 14, t);
977 }
978
979 // Send CCP request for no compression
980 static void initccp(tunnelidt t, sessionidt s)
981 {
982 char b[500], *q;
983
984 if (!(q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP)))
985 return;
986
987 LOG(4, s, t, "Sending CCP ConfigReq for no compression\n");
988 *q = ConfigReq;
989 *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
990 *(u16 *)(q + 2) = htons(4); // Length
991
992 LOG_HEX(5, "PPPCCP", q, 4);
993 tunnelsend(b, (q - b) + 4 , t);
994 }
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"