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2ca71f91c20ddf201b5bbaeaf12bd7c409ea9647
[l2tpns.git] / ppp.c
1 // L2TPNS PPP Stuff
2
3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.21 2004/11/05 04:55:27 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 struct configt *config;
25
26 void sendccp(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, 0, 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, 0, 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, 0, 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, 0, 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) { // Failed to make ppp header!
79 LOG(1,0,0,0, "Failed to make PPP header in process pap!\n");
80 return;
81 }
82 if (session[s].ip)
83 *p = 2; // ACK
84 else
85 *p = 3; // cant authorise
86 p[1] = id;
87 *(u16 *) (p + 2) = htons(5); // length
88 p[4] = 0; // no message
89 if (session[s].ip)
90 {
91 LOG(3, session[s].ip, s, t, "Already an IP allocated: %s (%d)\n", inet_toa(htonl(session[s].ip)), session[s].ip_pool_index);
92 session[s].flags &= ~SF_IPCP_ACKED;
93 }
94 else
95 {
96 LOG(1, 0, s, t, "No radius session available to authenticate session...\n");
97 }
98 LOG(3, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, 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, 0, s, t, "CHAP login %s\n", session[s].user);
224 radiussend(r, RADIUSAUTH);
225 }
226
227 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 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, 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, 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, 0, " Option length is %d...\n", length);
261 break;
262 }
263 if (type == 0)
264 {
265 LOG(4, 0, 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, 0, " %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
275 else
276 LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length);
277 break;
278 case 3: // Authentication-Protocol
279 {
280 if (length == 4)
281 {
282 int proto = ntohs(*(u16 *)(o + 2));
283 LOG(4, 0, 0, 0, " %s 0x%x (%s)\n", lcp_types[type], proto,
284 proto == PPPCHAP ? "CHAP" :
285 proto == PPPPAP ? "PAP" : "UNKNOWN");
286 }
287 else
288 LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length);
289 break;
290 }
291 case 4: // Quality-Protocol
292 {
293 u32 qp = ntohl(*(u32 *)(o + 2));
294 LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], qp);
295 break;
296 }
297 case 5: // Magic-Number
298 {
299 if (length == 6)
300 {
301 u32 magicno = ntohl(*(u32 *)(o + 2));
302 LOG(4, 0, 0, 0, " %s %x\n", lcp_types[type], magicno);
303 }
304 else
305 LOG(4, 0, 0, 0, " %s odd length %d\n", lcp_types[type], length);
306 break;
307 }
308 case 7: // Protocol-Field-Compression
309 {
310 LOG(4, 0, 0, 0, " %s\n", lcp_types[type]);
311 break;
312 }
313 case 8: // Address-And-Control-Field-Compression
314 {
315 LOG(4, 0, 0, 0, " %s\n", lcp_types[type]);
316 break;
317 }
318 default:
319 LOG(2, 0, 0, 0, " Unknown PPP LCP Option type %d\n", type);
320 break;
321 }
322 x -= length;
323 o += length;
324 }
325 }
326
327 // Process LCP messages
328 void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
329 {
330 u8 b[MAXCONTROL];
331 u8 *q = NULL;
332 u32 magicno = 0;
333 u16 hl;
334
335 CSTAT(call_processlcp);
336
337 LOG_HEX(5, "LCP", p, l);
338 if (l < 4)
339 {
340 LOG(1, session[s].ip, s, t, "Short LCP %d bytes\n", l);
341 STAT(tunnel_rx_errors);
342 return ;
343 }
344
345 if ((hl = ntohs(*(u16 *) (p + 2))) > l)
346 {
347 LOG(1, 0, s, t, "Length mismatch LCP %u/%u\n", hl, l);
348 STAT(tunnel_rx_errors);
349 return ;
350 }
351 l = hl;
352
353 if (*p == ConfigAck)
354 {
355 LOG(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n");
356 session[s].flags |= SF_LCP_ACKED;
357 }
358 else if (*p == ConfigReq)
359 {
360 int x = l - 4;
361 u8 *o = (p + 4);
362
363 LOG(3, session[s].ip, 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) break;
371 switch (type)
372 {
373 case 1: // Maximum-Receive-Unit
374 session[s].mru = ntohs(*(u16 *)(o + 2));
375 break;
376 case 2: // asyncmap
377 LOG_HEX(2, "PPP LCP Packet", p, l);
378 LOG(2, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
379 break;
380 case 3: // Authentication-Protocol
381 {
382 int proto = ntohs(*(u16 *)(o + 2));
383 if (proto == PPPCHAP)
384 {
385 LOG(2, session[s].ip, s, t, " Remote end is trying to do CHAP. Rejecting it.\n");
386
387 if (!q)
388 {
389 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
390 if (!q) {
391 LOG(2, session[s].ip, s, t, " Failed to send packet.\n");
392 break;
393 }
394 *q++ = ConfigNak;
395 }
396 memcpy(q, o, length);
397 *(u16 *)(q += 2) = htons(PPPPAP); // NAK -> Use PAP instead
398 q += length;
399 }
400 break;
401 }
402 case 5: // Magic-Number
403 {
404 magicno = ntohl(*(u32 *)(o + 2));
405 break;
406 }
407 case 4: // Quality-Protocol
408 case 7: // Protocol-Field-Compression
409 case 8: // Address-And-Control-Field-Compression
410 break;
411 case 13: // CallBack option for LCP extention of win2000/routers L2TP client
412 case 17:
413 case 18:
414 {
415 // Reject LCP CallBack
416 LOG(2, session[s].ip, s, t, " PPP LCP Option type %d, len=%d\n", type, length);
417 memcpy(p + 4, o, length);
418 *(u16 *)(p + 2) = htons(length + 4);
419 *p = ConfigRej;
420 q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP);
421 tunnelsend(b, 12 + length + 4, t);
422 return;
423 }
424
425 default:
426 // Reject Unknown LCP Option to stop to send it again
427 LOG(2, session[s].ip, s, t, " Unknown PPP LCP Option type %d\n", type);
428 memcpy(p + 4, o, length);
429 *(u16 *)(p + 2) = htons(length + 4);
430 *p = ConfigRej;
431 q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP);
432 tunnelsend(b, 12 + length + 4, t);
433 return;
434 }
435 x -= length;
436 o += length;
437 }
438
439 if (!(session[s].flags & SF_LCP_ACKED))
440 initlcp(t, s);
441
442 if (!q)
443 {
444 // Send back a ConfigAck
445 LOG(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n");
446 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
447 if (!q)
448 {
449 LOG(3, session[s].ip, s, t, " failed to create packet.\n");
450 return;
451 }
452 *q = ConfigAck;
453 tunnelsend(b, l + (q - b), t);
454 }
455 else
456 {
457 // Already built a ConfigNak... send it
458 LOG(3, session[s].ip, s, t, "Sending ConfigNak\n");
459 tunnelsend(b, l + (q - b), t);
460 }
461 }
462 else if (*p == ConfigNak)
463 {
464 LOG(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
465 if (config->debug > 3) dumplcp(p, l);
466 return ;
467 }
468 else if (*p == TerminateReq)
469 {
470 *p = TerminateAck; // close
471 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
472 if (!q) {
473 LOG(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n");
474 return;
475 }
476 LOG(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
477 sessionshutdown(s, "Remote end closed connection.");
478 tunnelsend(b, l + (q - b), t); // send it
479 }
480 else if (*p == TerminateAck)
481 {
482 sessionshutdown(s, "Connection closed.");
483 }
484 else if (*p == EchoReq)
485 {
486 *p = EchoReply; // reply
487 *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
488 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
489 if (!q) {
490 LOG(3, session[s].ip, s, t, " failed to send EchoReply.\n");
491 return;
492 }
493 LOG(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
494 tunnelsend(b, l + (q - b), t); // send it
495 }
496 else if (*p == EchoReply)
497 {
498 // Ignore it, last_packet time is set earlier than this.
499 }
500 else if (*p == IdentRequest)
501 {
502 *p = CodeRej;
503 if (l > MAXCONTROL)
504 {
505 LOG(1, 0, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
506 l = 1400;
507 }
508 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
509 if (!q)
510 {
511 LOG(3, session[s].ip, s, t, "Failed to create IdentRej.\n");
512 return;
513 }
514 LOG_HEX(5, "LCPIdentRej", q, l + 4);
515 tunnelsend(b, 12 + 4 + l, t);
516 }
517 else
518 {
519 LOG(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p);
520 STAT(tunnel_rx_errors);
521 return ;
522 }
523 }
524
525 // Process IPCP messages
526 void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l)
527 {
528 u16 hl;
529
530 CSTAT(call_processipcp);
531
532 LOG_HEX(5, "IPCP", p, l);
533 if (l < 5)
534 {
535 LOG(1, 0, s, t, "Short IPCP %d bytes\n", l);
536 STAT(tunnel_rx_errors);
537 return ;
538 }
539
540 if ((hl = ntohs(*(u16 *) (p + 2))) > l)
541 {
542 LOG(1, 0, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
543 STAT(tunnel_rx_errors);
544 return ;
545 }
546 l = hl;
547
548 if (*p == ConfigAck)
549 {
550 // happy with our IPCP
551 u16 r = session[s].radius;
552 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden)
553 {
554 if (!r)
555 r = radiusnew(s);
556 if (r)
557 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
558 }
559 session[s].flags |= SF_IPCP_ACKED;
560
561 LOG(3, session[s].ip, s, t, "IPCP Acked, session is now active\n");
562 return;
563 }
564 if (*p != ConfigReq)
565 {
566 LOG(1, 0, s, t, "Unexpected IPCP code %d\n", *p);
567 STAT(tunnel_rx_errors);
568 return ;
569 }
570 LOG(4, session[s].ip, s, t, "IPCP ConfigReq received\n");
571
572 if (!session[s].ip)
573 {
574 LOG(3, 0, s, t, "Waiting on radius reply\n");
575 return; // have to wait on RADIUS reply
576 }
577 // form a config reply quoting the IP in the session
578 {
579 u8 b[MAXCONTROL];
580 u8 *i,
581 *q;
582
583 q = p + 4;
584 i = p + l;
585 while (q < i && q[1])
586 {
587 if (*q != 0x81 && *q != 0x83 && *q != 3)
588 break;
589 q += q[1];
590 }
591 if (q < i)
592 {
593 // reject
594 u16 n = 4;
595 i = p + l;
596 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
597 {
598 LOG(2, 0, s, t, "Failed to send IPCP ConfigRej\n");
599 return;
600 }
601 *q = ConfigRej;
602 p += 4;
603 while (p < i && p[1])
604 {
605 if (*p != 0x81 && *p != 0x83 && *p != 3)
606 {
607 LOG(2, 0, s, t, "IPCP reject %d\n", *p);
608 memcpy(q + n, p, p[1]);
609 n += p[1];
610 }
611 p += p[1];
612 }
613 *(u16 *) (q + 2) = htons(n);
614 LOG(4, session[s].ip, s, t, "Sending ConfigRej\n");
615 tunnelsend(b, n + (q - b), t); // send it
616 }
617 else
618 {
619 LOG(4, session[s].ip, s, t, "Sending ConfigAck\n");
620 *p = ConfigAck;
621 if ((i = findppp(p, 0x81))) // Primary DNS address
622 {
623 if (*(u32 *) (i + 2) != htonl(session[s].dns1))
624 {
625 *(u32 *) (i + 2) = htonl(session[s].dns1);
626 *p = ConfigNak;
627 LOG(5, session[s].ip, s, t, " DNS1 = %s\n", inet_toa(session[s].dns1));
628 }
629 }
630 if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
631 {
632 if (*(u32 *) (i + 2) != htonl(session[s].dns2))
633 {
634 *(u32 *) (i + 2) = htonl(session[s].dns2);
635 *p = ConfigNak;
636 LOG(5, session[s].ip, s, t, " DNS2 = %s\n", inet_toa(session[s].dns2));
637 }
638 }
639 i = findppp(p, 3); // IP address
640 if (!i || i[1] != 6)
641 {
642 LOG(1, 0, s, t, "No IP in IPCP request\n");
643 STAT(tunnel_rx_errors);
644 return ;
645 }
646 if (*(u32 *) (i + 2) != htonl(session[s].ip))
647 {
648 *(u32 *) (i + 2) = htonl(session[s].ip);
649 *p = ConfigNak;
650 LOG(4, session[s].ip, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
651 inet_toa(htonl(session[s].ip)));
652 }
653 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
654 {
655 LOG(2, 0, s, t, " Failed to send IPCP packet.\n");
656 return;
657 }
658 tunnelsend(b, l + (q - b), t); // send it
659 }
660 }
661 }
662
663 // process IP packet received
664 //
665 // This MUST be called with at least 4 byte behind 'p'.
666 // (i.e. this routine writes to p[-4]).
667 void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l)
668 {
669 ipt ip;
670
671 CSTAT(call_processipin);
672
673 LOG_HEX(5, "IP", p, l);
674
675 ip = ntohl(*(u32 *)(p + 12));
676
677 if (l > MAXETHER)
678 {
679 LOG(1, ip, s, t, "IP packet too long %d\n", l);
680 STAT(tunnel_rx_errors);
681 return ;
682 }
683
684 // no spoof (do sessionbyip to handled statically routed subnets)
685 if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
686 {
687 LOG(5, ip, s, t, "Dropping packet with spoofed IP %s\n", inet_toa(htonl(ip)));
688 return;
689 }
690
691 if (session[s].snoop_ip && session[s].snoop_port)
692 {
693 // Snooping this session
694 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
695 }
696
697 // Add on the tun header
698 p -= 4;
699 *(u32 *)p = htonl(0x00000800);
700 l += 4;
701
702 if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
703 master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
704 return;
705 }
706
707 session[s].cin += l - 4;
708 session[s].total_cin += l - 4;
709 sess_count[s].cin += l - 4;
710
711 session[s].pin++;
712 eth_tx += l - 4;
713
714 STAT(tun_tx_packets);
715 INC_STAT(tun_tx_bytes, l);
716
717 if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
718 tbf_queue_packet(session[s].tbf_in, p, l);
719 return;
720 }
721
722 // send to ethernet
723 if (tun_write(p, l) < 0)
724 {
725 STAT(tun_tx_errors);
726 LOG(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
727 l, strerror(errno), tunfd, p);
728 }
729
730 }
731
732 //
733 // Helper routine for the TBF filters.
734 // Used to send queued data in from the user.
735 //
736 void send_ipin(sessionidt s, u8 *buf, int len)
737 {
738 LOG_HEX(5, "IP in throttled", buf, len);
739 if (write(tunfd, buf, len) < 0)
740 {
741 STAT(tun_tx_errors);
742 LOG(0, 0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
743 len, strerror(errno), tunfd, buf);
744 }
745
746 // Increment packet counters
747 session[s].cin += len - 4;
748 session[s].total_cin += len - 4;
749 sess_count[s].cin += len - 4;
750
751 session[s].pin++;
752 eth_tx += len - 4;
753 }
754
755
756 // Process CCP messages
757 void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l)
758 {
759
760 CSTAT(call_processccp);
761
762 LOG_HEX(5, "CCP", p, l);
763 if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
764 {
765 LOG(1, 0, s, t, "Unexpected CCP request code %d\n", *p);
766 STAT(tunnel_rx_errors);
767 return ;
768 }
769 // reject
770 {
771 u8 b[MAXCONTROL];
772 u8 *q;
773 if (*p == ConfigReq)
774 {
775 if (l < 6)
776 {
777 *p = ConfigAck; // accept no compression
778 }
779 else
780 {
781 *p = ConfigRej; // reject
782 sendccp(t, s);
783 }
784 }
785 else
786 *p = TerminateAck; // close
787 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
788 {
789 LOG(1,0,0,0, "Failed to send CCP packet.\n");
790 return;
791 }
792 tunnelsend(b, l + (q - b), t); // send it
793 }
794 }
795
796 // send a CHAP PP packet
797 void sendchap(tunnelidt t, sessionidt s)
798 {
799 u8 b[MAXCONTROL];
800 u16 r = session[s].radius;
801 u8 *q;
802
803 CSTAT(call_sendchap);
804
805 if (!r)
806 {
807 LOG(1, 0, s, t, "No RADIUS to send challenge\n");
808 STAT(tunnel_tx_errors);
809 return ;
810 }
811 LOG(1, 0, s, t, "Send CHAP challenge\n");
812 {
813 // new challenge
814 int n;
815 for (n = 0; n < 15; n++)
816 radius[r].auth[n] = rand();
817 }
818 radius[r].chap = 1; // CHAP not PAP
819 radius[r].id++;
820 if (radius[r].state != RADIUSCHAP)
821 radius[r].try = 0;
822 radius[r].state = RADIUSCHAP;
823 radius[r].retry = backoff(radius[r].try++);
824 if (radius[r].try > 5)
825 {
826 sessionshutdown(s, "Timeout CHAP");
827 STAT(tunnel_tx_errors);
828 return ;
829 }
830 q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
831 if (!q) {
832 LOG(1, 0, s, t, "failed to send CHAP challenge.\n");
833 return;
834 }
835 *q = 1; // challenge
836 q[1] = radius[r].id; // ID
837 q[4] = 16; // length
838 memcpy(q + 5, radius[r].auth, 16); // challenge
839 strcpy(q + 21, hostname); // our name
840 *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
841 tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
842 }
843
844 // fill in a L2TP message with a PPP frame,
845 // copies existing PPP message and changes magic number if seen
846 // returns start of PPP frame
847 u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype)
848 {
849 if (size < 12)
850 return NULL; // Need more space than this!!
851
852 *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
853 *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
854 *(u16 *) (b + 4) = htons(session[s].far); // session
855 b += 6;
856 if (mtype == PPPLCP || !(session[s].l2tp_flags & SESSIONACFC))
857 {
858 *(u16 *) b = htons(0xFF03); // HDLC header
859 b += 2;
860 }
861 if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
862 *b++ = mtype;
863 else
864 {
865 *(u16 *) b = htons(mtype);
866 b += 2;
867 }
868
869 if (l + 12 > size) {
870 LOG(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l);
871 return NULL; // Run out of room to hold the packet!
872 }
873 if (p && l)
874 memcpy(b, p, l);
875 return b;
876 }
877
878 // find a PPP option, returns point to option, or 0 if not found
879 u8 *findppp(u8 *b, u8 mtype)
880 {
881 u16 l = ntohs(*(u16 *) (b + 2));
882 if (l < 4)
883 return 0;
884 b += 4;
885 l -= 4;
886 while (l)
887 {
888 if (l < b[1] || !b[1])
889 return 0; // faulty
890 if (*b == mtype)
891 return b;
892 l -= b[1];
893 b += b[1];
894 }
895 return 0;
896 }
897
898 // Send initial LCP ConfigReq
899 void initlcp(tunnelidt t, sessionidt s)
900 {
901 char b[500] = {0}, *q;
902
903 q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
904 if (!q) {
905 LOG(1, 0, s, t, "Failed to send LCP ConfigReq.\n");
906 return;
907 }
908 LOG(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
909 *q = ConfigReq;
910 *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
911 *(u16 *)(q + 2) = htons(14); // Length
912 *(u8 *)(q + 4) = 5;
913 *(u8 *)(q + 5) = 6;
914 *(u32 *)(q + 6) = htonl(session[s].magic);
915 *(u8 *)(q + 10) = 3;
916 *(u8 *)(q + 11) = 4;
917 *(u16 *)(q + 12) = htons(PPPPAP); // PAP
918 tunnelsend(b, 12 + 14, t);
919 }
920
921 // Send CCP reply
922 void sendccp(tunnelidt t, sessionidt s)
923 {
924 char *q, b[500] = {0};
925
926 q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP);
927 *q = ConfigReq;
928 *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
929 *(u16 *)(q + 2) = htons(4); // Length
930 LOG_HEX(5, "PPPCCP", q, 4);
931 tunnelsend(b, (q - b) + 4 , t);
932 }
933
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"