ppp.c

   1 // L2TPNS PPP Stuff
   2
   3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.90 2005/12/15 14:18:16 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 int add_lcp_auth(uint8_t *b, int size, int authtype);
  27
  28 // Process PAP messages
  29 void processpap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
  30 {
  31         char user[MAXUSER];
  32         char pass[MAXPASS];
  33         uint16_t hl;
  34         uint16_t r;
  35
  36         CSTAT(processpap);
  37
  38         LOG_HEX(5, "PAP", p, l);
  39         if (l < 4)
  40         {
  41                 LOG(1, s, t, "Short PAP %u bytes\n", l);
  42                 STAT(tunnel_rx_errors);
  43                 sessionshutdown(s, "Short PAP packet.", 3, 0);
  44                 return;
  45         }
  46
  47         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
  48         {
  49                 LOG(1, s, t, "Length mismatch PAP %u/%u\n", hl, l);
  50                 STAT(tunnel_rx_errors);
  51                 sessionshutdown(s, "PAP length mismatch.", 3, 0);
  52                 return;
  53         }
  54         l = hl;
  55
  56         if (*p != 1)
  57         {
  58                 LOG(1, s, t, "Unexpected PAP code %d\n", *p);
  59                 STAT(tunnel_rx_errors);
  60                 sessionshutdown(s, "Unexpected PAP code.", 3, 0);
  61                 return;
  62         }
  63
  64         if (session[s].ppp.phase != Authenticate)
  65         {
  66                 LOG(2, s, t, "PAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
  67                 return;
  68         }
  69
  70         {
  71                 uint8_t *b = p;
  72                 b += 4;
  73                 user[0] = pass[0] = 0;
  74                 if (*b && *b < sizeof(user))
  75                 {
  76                         memcpy(user, b + 1, *b);
  77                         user[*b] = 0;
  78                         b += 1 + *b;
  79                         if (*b && *b < sizeof(pass))
  80                         {
  81                                 memcpy(pass, b + 1, *b);
  82                                 pass[*b] = 0;
  83                         }
  84                 }
  85                 LOG(3, s, t, "PAP login %s/%s\n", user, pass);
  86         }
  87
  88         if (session[s].ip || !(r = radiusnew(s)))
  89         {
  90                 // respond now, either no RADIUS available or already authenticated
  91                 uint8_t b[MAXETHER];
  92                 uint8_t id = p[1];
  93                 uint8_t *p = makeppp(b, sizeof(b), 0, 0, s, t, PPPPAP);
  94                 if (!p) return;
  95
  96                 if (session[s].ip)
  97                         *p = 2;                         // ACK
  98                 else
  99                         *p = 3;                         // cant authorise
 100                 p[1] = id;
 101                 *(uint16_t *) (p + 2) = htons(5);       // length
 102                 p[4] = 0;                               // no message
 103                 tunnelsend(b, 5 + (p - b), t);          // send it
 104
 105                 if (session[s].ip)
 106                 {
 107                         LOG(3, s, t, "Already an IP allocated: %s (%d)\n",
 108                                 fmtaddr(htonl(session[s].ip), 0), session[s].ip_pool_index);
 109                 }
 110                 else
 111                 {
 112                         LOG(1, s, t, "No RADIUS session available to authenticate session...\n");
 113                         sessionshutdown(s, "No free RADIUS sessions.", 4, 0);
 114                 }
 115         }
 116         else
 117         {
 118                 // Run PRE_AUTH plugins
 119                 struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
 120                 run_plugins(PLUGIN_PRE_AUTH, &packet);
 121                 if (!packet.continue_auth)
 122                 {
 123                         LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
 124                         if (packet.username) free(packet.username);
 125                         if (packet.password) free(packet.password);
 126                         return;
 127                 }
 128
 129                 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
 130                 strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
 131
 132                 free(packet.username);
 133                 free(packet.password);
 134
 135                 radius[r].id = p[1];
 136                 LOG(3, s, t, "Sending login for %s/%s to RADIUS\n", user, pass);
 137                 radiussend(r, RADIUSAUTH);
 138         }
 139 }
 140
 141 // Process CHAP messages
 142 void processchap(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 143 {
 144         uint16_t r;
 145         uint16_t hl;
 146
 147         CSTAT(processchap);
 148
 149         LOG_HEX(5, "CHAP", p, l);
 150
 151         if (l < 4)
 152         {
 153                 LOG(1, s, t, "Short CHAP %u bytes\n", l);
 154                 STAT(tunnel_rx_errors);
 155                 sessionshutdown(s, "Short CHAP packet.", 3, 0);
 156                 return;
 157         }
 158
 159         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 160         {
 161                 LOG(1, s, t, "Length mismatch CHAP %u/%u\n", hl, l);
 162                 STAT(tunnel_rx_errors);
 163                 sessionshutdown(s, "CHAP length mismatch.", 3, 0);
 164                 return;
 165         }
 166         l = hl;
 167
 168         if (*p != 2)
 169         {
 170                 LOG(1, s, t, "Unexpected CHAP response code %d\n", *p);
 171                 STAT(tunnel_rx_errors);
 172                 sessionshutdown(s, "CHAP length mismatch.", 3, 0);
 173                 return;
 174         }
 175
 176         r = sess_local[s].radius;
 177         if (!r)
 178         {
 179                 LOG(3, s, t, "Unexpected CHAP message\n");
 180                 return;
 181         }
 182
 183         if (session[s].ppp.phase != Authenticate)
 184         {
 185                 LOG(2, s, t, "CHAP ignored in %s phase\n", ppp_phase(session[s].ppp.phase));
 186                 return;
 187         }
 188
 189         if (p[1] != radius[r].id)
 190         {
 191                 LOG(1, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
 192                 STAT(tunnel_rx_errors);
 193                 sessionshutdown(s, "Unexpected CHAP response ID.", 3, 0);
 194                 return;
 195         }
 196
 197         if (l < 5 || p[4] != 16)
 198         {
 199                 LOG(1, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]);
 200                 STAT(tunnel_rx_errors);
 201                 sessionshutdown(s, "Bad CHAP response length.", 3, 0);
 202                 return;
 203         }
 204
 205         l -= 5;
 206         p += 5;
 207         if (l < 16 || l - 16 >= sizeof(session[s].user))
 208         {
 209                 LOG(1, s, t, "CHAP user too long %d\n", l - 16);
 210                 STAT(tunnel_rx_errors);
 211                 sessionshutdown(s, "CHAP username too long.", 3, 0);
 212                 return;
 213         }
 214
 215         // Run PRE_AUTH plugins
 216         {
 217                 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
 218
 219                 packet.password = calloc(17, 1);
 220                 memcpy(packet.password, p, 16);
 221
 222                 p += 16;
 223                 l -= 16;
 224
 225                 packet.username = calloc(l + 1, 1);
 226                 memcpy(packet.username, p, l);
 227
 228                 run_plugins(PLUGIN_PRE_AUTH, &packet);
 229                 if (!packet.continue_auth)
 230                 {
 231                         LOG(3, s, t, "A plugin rejected PRE_AUTH\n");
 232                         if (packet.username) free(packet.username);
 233                         if (packet.password) free(packet.password);
 234                         return;
 235                 }
 236
 237                 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
 238                 memcpy(radius[r].pass, packet.password, 16);
 239
 240                 free(packet.username);
 241                 free(packet.password);
 242         }
 243
 244         radius[r].chap = 1;
 245         LOG(3, s, t, "CHAP login %s\n", session[s].user);
 246         radiussend(r, RADIUSAUTH);
 247 }
 248
 249 static void dumplcp(uint8_t *p, int l)
 250 {
 251         int x = l - 4;
 252         uint8_t *o = (p + 4);
 253
 254         LOG_HEX(5, "PPP LCP Packet", p, l);
 255         LOG(4, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_code((int)*p), ntohs( ((uint16_t *) p)[1]) );
 256         LOG(4, 0, 0, "Length: %d\n", l);
 257         if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
 258                 return;
 259
 260         while (x > 2)
 261         {
 262                 int type = o[0];
 263                 int length = o[1];
 264                 if (length < 2)
 265                 {
 266                         LOG(4, 0, 0, "  Option length is %d...\n", length);
 267                         break;
 268                 }
 269                 if (type == 0)
 270                 {
 271                         LOG(4, 0, 0, "  Option type is 0...\n");
 272                         x -= length;
 273                         o += length;
 274                         continue;
 275                 }
 276                 switch (type)
 277                 {
 278                         case 1: // Maximum-Receive-Unit
 279                                 if (length == 4)
 280                                         LOG(4, 0, 0, "    %s %d\n", ppp_lcp_option(type), ntohs(*(uint16_t *)(o + 2)));
 281                                 else
 282                                         LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
 283                                 break;
 284                         case 2: // Async-Control-Character-Map
 285                                 if (length == 6)
 286                                 {
 287                                         uint32_t asyncmap = ntohl(*(uint32_t *)(o + 2));
 288                                         LOG(4, 0, 0, "    %s %x\n", ppp_lcp_option(type), asyncmap);
 289                                 }
 290                                 else
 291                                         LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
 292                                 break;
 293                         case 3: // Authentication-Protocol
 294                                 if (length == 4)
 295                                 {
 296                                         int proto = ntohs(*(uint16_t *)(o + 2));
 297                                         LOG(4, 0, 0, "    %s 0x%x (%s)\n", ppp_lcp_option(type), proto,
 298                                                 proto == PPPPAP  ? "PAP"  : "UNSUPPORTED");
 299                                 }
 300                                 else if (length == 5)
 301                                 {
 302                                         int proto = ntohs(*(uint16_t *)(o + 2));
 303                                         int algo = *(o + 4);
 304                                         LOG(4, 0, 0, "    %s 0x%x 0x%x (%s)\n", ppp_lcp_option(type), proto, algo,
 305                                                 (proto == PPPCHAP && algo == 5) ? "CHAP MD5"  : "UNSUPPORTED");
 306                                 }
 307                                 else
 308                                         LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
 309                                 break;
 310                         case 4: // Quality-Protocol
 311                                 {
 312                                         uint32_t qp = ntohl(*(uint32_t *)(o + 2));
 313                                         LOG(4, 0, 0, "    %s %x\n", ppp_lcp_option(type), qp);
 314                                 }
 315                                 break;
 316                         case 5: // Magic-Number
 317                                 if (length == 6)
 318                                 {
 319                                         uint32_t magicno = ntohl(*(uint32_t *)(o + 2));
 320                                         LOG(4, 0, 0, "    %s %x\n", ppp_lcp_option(type), magicno);
 321                                 }
 322                                 else
 323                                         LOG(4, 0, 0, "    %s odd length %d\n", ppp_lcp_option(type), length);
 324                                 break;
 325                         case 7: // Protocol-Field-Compression
 326                         case 8: // Address-And-Control-Field-Compression
 327                                 LOG(4, 0, 0, "    %s\n", ppp_lcp_option(type));
 328                                 break;
 329                         default:
 330                                 LOG(2, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
 331                                 break;
 332                 }
 333                 x -= length;
 334                 o += length;
 335         }
 336 }
 337
 338 void lcp_open(sessionidt s, tunnelidt t)
 339 {
 340         // transition to Authentication or Network phase:
 341         session[s].ppp.phase = sess_local[s].lcp_authtype ? Authenticate : Network;
 342
 343         LOG(3, s, t, "LCP: Opened, phase %s\n", ppp_phase(session[s].ppp.phase));
 344
 345         // LCP now Opened
 346         change_state(s, lcp, Opened);
 347
 348         if (session[s].ppp.phase == Authenticate)
 349         {
 350                 if (sess_local[s].lcp_authtype == AUTHCHAP)
 351                         sendchap(s, t);
 352         }
 353         else
 354         {
 355                 // This-Layer-Up
 356                 sendipcp(s, t);
 357                 change_state(s, ipcp, RequestSent);
 358                 // move to passive state for IPv6 (if configured), CCP
 359                 if (config->ipv6_prefix.s6_addr[0])
 360                         change_state(s, ipv6cp, Stopped);
 361                 else
 362                         change_state(s, ipv6cp, Closed);
 363
 364                 change_state(s, ccp, Stopped);
 365         }
 366 }
 367
 368 static void lcp_restart(sessionidt s)
 369 {
 370         session[s].ppp.phase = Establish;
 371         // This-Layer-Down
 372         change_state(s, ipcp, Dead);
 373         change_state(s, ipv6cp, Dead);
 374         change_state(s, ccp, Dead);
 375 }
 376
 377 static uint8_t *ppp_conf_rej(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
 378         uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option)
 379 {
 380         if (!*response || **response != ConfigRej)
 381         {
 382                 queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype);
 383                 if (!queued)
 384                         return 0;
 385
 386                 *queued = ConfigRej;
 387                 queued += 4;
 388         }
 389
 390         if ((queued - buf + option[1]) > blen)
 391         {
 392                 LOG(2, s, session[s].tunnel, "PPP overflow for ConfigRej (proto %u, option %u).\n", mtype, *option);
 393                 return 0;
 394         }
 395
 396         memcpy(queued, option, option[1]);
 397         return queued + option[1];
 398 }
 399
 400 static uint8_t *ppp_conf_nak(sessionidt s, uint8_t *buf, size_t blen, uint16_t mtype,
 401         uint8_t **response, uint8_t *queued, uint8_t *packet, uint8_t *option,
 402         uint8_t *value, size_t vlen)
 403 {
 404         int *nak_sent;
 405         switch (mtype)
 406         {
 407         case PPPLCP:    nak_sent = &sess_local[s].lcp.nak_sent;    break;
 408         case PPPIPCP:   nak_sent = &sess_local[s].ipcp.nak_sent;   break;
 409         case PPPIPV6CP: nak_sent = &sess_local[s].ipv6cp.nak_sent; break;
 410         default:        return 0; // ?
 411         }
 412
 413         if (*response && **response != ConfigNak)
 414         {
 415                 if (*nak_sent < config->ppp_max_failure) // reject queued
 416                         return queued;
 417
 418                 return ppp_conf_rej(s, buf, blen, mtype, response, 0, packet, option);
 419         }
 420
 421         if (!*response)
 422         {
 423                 if (*nak_sent >= config->ppp_max_failure)
 424                         return ppp_conf_rej(s, buf, blen, mtype, response, 0, packet, option);
 425
 426                 queued = *response = makeppp(buf, blen, packet, 2, s, session[s].tunnel, mtype);
 427                 if (!queued)
 428                         return 0;
 429
 430                 (*nak_sent)++;
 431                 *queued = ConfigNak;
 432                 queued += 4;
 433         }
 434
 435         if ((queued - buf + vlen + 2) > blen)
 436         {
 437                 LOG(2, s, session[s].tunnel, "PPP overflow for ConfigNak (proto %u, option %u).\n", mtype, *option);
 438                 return 0;
 439         }
 440
 441         *queued++ = *option;
 442         *queued++ = vlen + 2;
 443         memcpy(queued, value, vlen);
 444         return queued + vlen;
 445 }
 446
 447 static void ppp_code_rej(sessionidt s, tunnelidt t, uint16_t proto,
 448         char *pname, uint8_t *p, uint16_t l, uint8_t *buf, size_t size)
 449 {
 450         uint8_t *q;
 451         int mru = session[s].mru;
 452         if (mru < MINMTU) mru = MINMTU;
 453         if (mru > size) mru = size;
 454
 455         l += 4;
 456         if (l > mru) l = mru;
 457
 458         q = makeppp(buf, size, 0, 0, s, t, proto);
 459         if (!q) return;
 460
 461         *q = CodeRej;
 462         *(q + 1) = ++sess_local[s].lcp_ident;
 463         *(uint16_t *)(q + 2) = htons(l);
 464         memcpy(q + 4, p, l - 4);
 465
 466         LOG(2, s, t, "Unexpected %s code %s\n", pname, ppp_code(*p));
 467         LOG(3, s, t, "%s: send %s\n", pname, ppp_code(*q));
 468         if (config->debug > 3) dumplcp(q, l);
 469
 470         tunnelsend(buf, l + (q - buf), t);
 471 }
 472
 473 // Process LCP messages
 474 void processlcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 475 {
 476         uint8_t b[MAXETHER];
 477         uint8_t *q = NULL;
 478         uint32_t magicno = 0;
 479         uint16_t hl;
 480
 481         CSTAT(processlcp);
 482
 483         LOG_HEX(5, "LCP", p, l);
 484         if (l < 4)
 485         {
 486                 LOG(1, s, t, "Short LCP %d bytes\n", l);
 487                 STAT(tunnel_rx_errors);
 488                 return ;
 489         }
 490
 491         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 492         {
 493                 LOG(1, s, t, "Length mismatch LCP %u/%u\n", hl, l);
 494                 STAT(tunnel_rx_errors);
 495                 return ;
 496         }
 497         l = hl;
 498
 499         if (session[s].die) // going down...
 500                 return;
 501
 502         LOG((*p == EchoReq || *p == EchoReply) ? 4 : 3, s, t,
 503                 "LCP: recv %s\n", ppp_code(*p));
 504
 505         if (config->debug > 3) dumplcp(p, l);
 506
 507         if (*p == ConfigAck)
 508         {
 509                 int x = l - 4;
 510                 uint8_t *o = (p + 4);
 511                 int authtype = 0;
 512
 513                 while (x > 2)
 514                 {
 515                         int type = o[0];
 516                         int length = o[1];
 517
 518                         if (length == 0 || type == 0 || x < length) break;
 519                         switch (type)
 520                         {
 521                                 case 3: // Authentication-Protocol
 522                                         {
 523                                                 int proto = ntohs(*(uint16_t *)(o + 2));
 524                                                 if (proto == PPPPAP)
 525                                                         authtype = AUTHPAP;
 526                                                 else if (proto == PPPCHAP && *(o + 4) == 5)
 527                                                         authtype = AUTHCHAP;
 528                                         }
 529
 530                                         break;
 531                         }
 532                         x -= length;
 533                         o += length;
 534                 }
 535
 536                 if (!session[s].ip && authtype)
 537                         sess_local[s].lcp_authtype = authtype;
 538
 539                 switch (session[s].ppp.lcp)
 540                 {
 541                 case RequestSent:
 542                         initialise_restart_count(s, lcp);
 543                         change_state(s, lcp, AckReceived);
 544                         break;
 545
 546                 case AckReceived:
 547                 case Opened:
 548                         LOG(2, s, t, "LCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
 549                         if (session[s].ppp.lcp == Opened)
 550                                 lcp_restart(s);
 551
 552                         sendlcp(s, t);
 553                         change_state(s, lcp, RequestSent);
 554                         break;
 555
 556                 case AckSent:
 557                         lcp_open(s, t);
 558                         break;
 559
 560                 default:
 561                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 562                 }
 563         }
 564         else if (*p == ConfigReq)
 565         {
 566                 int x = l - 4;
 567                 uint8_t *o = (p + 4);
 568                 uint8_t *response = 0;
 569                 static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
 570                 static uint8_t authproto[5];
 571
 572                 while (x > 2)
 573                 {
 574                         int type = o[0];
 575                         int length = o[1];
 576
 577                         if (length == 0 || type == 0 || x < length) break;
 578                         switch (type)
 579                         {
 580                                 case 1: // Maximum-Receive-Unit
 581                                         {
 582                                                 uint16_t mru = ntohs(*(uint16_t *)(o + 2));
 583                                                 if (mru >= MINMTU)
 584                                                 {
 585                                                         session[s].mru = mru;
 586                                                         break;
 587                                                 }
 588
 589                                                 LOG(3, s, t, "    Remote requesting MRU of %u.  Rejecting.\n", mru);
 590                                                 mru = htons(MRU);
 591                                                 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
 592                                         }
 593                                         break;
 594
 595                                 case 2: // Async-Control-Character-Map
 596                                         if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
 597                                                 break;
 598
 599                                         LOG(3, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
 600                                         q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, asyncmap, sizeof(asyncmap));
 601                                         break;
 602
 603                                 case 3: // Authentication-Protocol
 604                                         {
 605                                                 int proto = ntohs(*(uint16_t *)(o + 2));
 606                                                 char proto_name[] = "0x0000";
 607                                                 int alen;
 608
 609                                                 if (proto == PPPPAP)
 610                                                 {
 611                                                         if (config->radius_authtypes & AUTHPAP)
 612                                                         {
 613                                                                 sess_local[s].lcp_authtype = AUTHPAP;
 614                                                                 break;
 615                                                         }
 616
 617                                                         strcpy(proto_name, "PAP");
 618                                                 }
 619                                                 else if (proto == PPPCHAP)
 620                                                 {
 621                                                         if (config->radius_authtypes & AUTHCHAP
 622                                                             && *(o + 4) == 5) // MD5
 623                                                         {
 624                                                                 sess_local[s].lcp_authtype = AUTHCHAP;
 625                                                                 break;
 626                                                         }
 627
 628                                                         strcpy(proto_name, "CHAP");
 629                                                 }
 630                                                 else
 631                                                         sprintf(proto_name, "%#4.4x", proto);
 632
 633                                                 LOG(3, s, t, "    Remote requesting %s authentication.  Rejecting.\n", proto_name);
 634
 635                                                 alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
 636                                                 if (alen < 2) break; // paranoia
 637
 638                                                 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
 639                                                 if (q && *response == ConfigNak &&
 640                                                         config->radius_authtypes != config->radius_authprefer)
 641                                                 {
 642                                                         // alternate type
 643                                                         alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
 644                                                         if (alen < 2) break;
 645                                                         q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
 646                                                 }
 647
 648                                                 break;
 649                                         }
 650                                         break;
 651
 652                                 case 5: // Magic-Number
 653                                         magicno = ntohl(*(uint32_t *)(o + 2));
 654                                         break;
 655
 656                                 case 4: // Quality-Protocol
 657                                 case 7: // Protocol-Field-Compression
 658                                 case 8: // Address-And-Control-Field-Compression
 659                                         break;
 660
 661                                 default: // Reject any unknown options
 662                                         LOG(3, s, t, "    Rejecting unknown PPP LCP option %d\n", type);
 663                                         q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
 664                         }
 665                         x -= length;
 666                         o += length;
 667                 }
 668
 669                 if (response)
 670                 {
 671                         l = q - response; // LCP packet length
 672                         *((uint16_t *) (response + 2)) = htons(l); // update header
 673                 }
 674                 else
 675                 {
 676                         // Send packet back as ConfigAck
 677                         response = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
 678                         if (!response) return;
 679                         *response = ConfigAck;
 680                 }
 681
 682                 switch (session[s].ppp.lcp)
 683                 {
 684                 case Closed:
 685                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
 686                         if (!response) return;
 687                         *response = TerminateAck;
 688                         *((uint16_t *) (response + 2)) = htons(l = 4);
 689                         break;
 690
 691                 case Stopped:
 692                         initialise_restart_count(s, lcp);
 693                         sendlcp(s, t);
 694                         if (*response == ConfigAck)
 695                                 change_state(s, lcp, AckSent);
 696                         else
 697                                 change_state(s, lcp, RequestSent);
 698
 699                         break;
 700
 701                 case RequestSent:
 702                         if (*response == ConfigAck)
 703                                 change_state(s, lcp, AckSent);
 704
 705                         break;
 706
 707                 case AckReceived:
 708                         if (*response == ConfigAck)
 709                                 lcp_open(s, t);
 710
 711                         break;
 712
 713                 case Opened:
 714                         lcp_restart(s);
 715                         sendlcp(s, t);
 716                         /* fallthrough */
 717
 718                 case AckSent:
 719                         if (*response == ConfigAck)
 720                                 change_state(s, lcp, AckSent);
 721                         else
 722                                 change_state(s, lcp, RequestSent);
 723
 724                         break;
 725
 726                 default:
 727                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 728                         return;
 729                 }
 730
 731                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
 732                 if (config->debug > 3) dumplcp(response, l);
 733
 734                 tunnelsend(b, l + (response - b), t);
 735         }
 736         else if (*p == ConfigNak || *p == ConfigRej)
 737         {
 738                 int x = l - 4;
 739                 uint8_t *o = (p + 4);
 740                 int authtype = -1;
 741
 742                 while (x > 2)
 743                 {
 744                         int type = o[0];
 745                         int length = o[1];
 746
 747                         if (length == 0 || type == 0 || x < length) break;
 748                         switch (type)
 749                         {
 750                                 case 1: // Maximum-Receive-Unit
 751                                         if (*p == ConfigNak)
 752                                         {
 753                                                 sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
 754                                                 LOG(3, s, t, "    Remote requested MRU of %u\n", sess_local[s].ppp_mru);
 755                                         }
 756                                         else
 757                                         {
 758                                                 sess_local[s].ppp_mru = 0;
 759                                                 LOG(3, s, t, "    Remote rejected MRU negotiation\n");
 760                                         }
 761
 762                                         break;
 763
 764                                 case 3: // Authentication-Protocol
 765                                         if (authtype > 0)
 766                                                 break;
 767
 768                                         if (*p == ConfigNak)
 769                                         {
 770                                                 int proto = ntohs(*(uint16_t *)(o + 2));
 771                                                 if (proto == PPPPAP)
 772                                                 {
 773                                                         authtype = config->radius_authtypes & AUTHPAP;
 774                                                         LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
 775                                                                 authtype ? "accept" : "reject");
 776                                                 }
 777                                                 else if (proto == PPPCHAP && *(o + 4) == 5)
 778                                                 {
 779                                                         authtype = config->radius_authtypes & AUTHCHAP;
 780                                                         LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
 781                                                                 authtype ? "accept" : "reject");
 782                                                 }
 783                                                 else
 784                                                 {
 785                                                         LOG(3, s, t, "    Rejecting unsupported authentication %#4x\n",
 786                                                                 proto);
 787                                                 }
 788                                         }
 789                                         else
 790                                         {
 791                                                 LOG(2, s, t, "LCP: remote rejected auth negotiation\n");
 792                                                 authtype = 0; // shutdown
 793                                         }
 794
 795                                         break;
 796
 797                                 default:
 798                                         LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
 799                                         break;
 800                         }
 801                         x -= length;
 802                         o += length;
 803                 }
 804
 805                 if (!authtype)
 806                 {
 807                         sessionshutdown(s, "Unsupported authentication.", 3, 0);
 808                         return;
 809                 }
 810
 811                 if (authtype > 0)
 812                         sess_local[s].lcp_authtype = authtype;
 813
 814                 switch (session[s].ppp.lcp)
 815                 {
 816                 case Closed:
 817                 case Stopped:
 818                         {
 819                                 uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
 820                                 if (!response) return;
 821                                 *response = TerminateAck;
 822                                 *((uint16_t *) (response + 2)) = htons(l = 4);
 823
 824                                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
 825                                 if (config->debug > 3) dumplcp(response, l);
 826
 827                                 tunnelsend(b, l + (response - b), t);
 828                         }
 829                         break;
 830
 831                 case RequestSent:
 832                 case AckSent:
 833                         initialise_restart_count(s, lcp);
 834                         sendlcp(s, t);
 835                         break;
 836
 837                 case AckReceived:
 838                         LOG(2, s, t, "LCP: ConfigNak in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
 839                         sendlcp(s, t);
 840                         break;
 841
 842                 case Opened:
 843                         lcp_restart(s);
 844                         sendlcp(s, t);
 845                         break;
 846
 847                 default:
 848                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 849                         return;
 850                 }
 851         }
 852         else if (*p == TerminateReq)
 853         {
 854                 *p = TerminateAck;      // close
 855                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPLCP);
 856                 if (!q) return;
 857
 858                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
 859                 if (config->debug > 3) dumplcp(q, l);
 860
 861                 tunnelsend(b, l + (q - b), t); // send it
 862                 sessionshutdown(s, "Remote end closed connection.", 3, 0);
 863         }
 864         else if (*p == TerminateAck)
 865         {
 866                 sessionshutdown(s, "Connection closed.", 3, 0);
 867         }
 868         else if (*p == ProtocolRej)
 869         {
 870                 uint16_t proto = 0;
 871
 872                 if (l > 4)
 873                 {
 874                         proto = *(p+4);
 875                         if (l > 5 && !(proto & 1))
 876                         {
 877                                 proto <<= 8;
 878                                 proto |= *(p+5);
 879                         }
 880                 }
 881
 882                 if (proto == PPPIPV6CP)
 883                 {
 884                         LOG(3, s, t, "IPv6 rejected\n");
 885                         change_state(s, ipv6cp, Closed);
 886                 }
 887                 else
 888                 {
 889                         LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
 890                 }
 891         }
 892         else if (*p == EchoReq)
 893         {
 894                 *p = EchoReply;         // reply
 895                 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
 896                 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
 897                 if (!q) return;
 898
 899                 LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
 900                 if (config->debug > 3) dumplcp(q, l);
 901
 902                 tunnelsend(b, l + (q - b), t); // send it
 903         }
 904         else if (*p == EchoReply)
 905         {
 906                 // Ignore it, last_packet time is set earlier than this.
 907         }
 908         else if (*p != CodeRej)
 909         {
 910                 ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
 911         }
 912 }
 913
 914 static void ipcp_open(sessionidt s, tunnelidt t)
 915 {
 916         LOG(3, s, t, "IPCP: Opened, session is now active\n");
 917
 918         change_state(s, ipcp, Opened);
 919
 920         if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
 921         {
 922                 uint16_t r = radiusnew(s);
 923                 if (r)
 924                 {
 925                         radiussend(r, RADIUSSTART); // send radius start
 926
 927                         // don't send further Start records if IPCP is restarted
 928                         session[s].flags |= SESSION_STARTED;
 929                         cluster_send_session(s);
 930                 }
 931         }
 932
 933         // start IPv6 if configured and still in passive state
 934         if (session[s].ppp.ipv6cp == Stopped)
 935         {
 936                 sendipv6cp(s, t);
 937                 change_state(s, ipv6cp, RequestSent);
 938         }
 939 }
 940
 941 // Process IPCP messages
 942 void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 943 {
 944         uint8_t b[MAXETHER];
 945         uint8_t *q = 0;
 946         uint16_t hl;
 947
 948         CSTAT(processipcp);
 949
 950         LOG_HEX(5, "IPCP", p, l);
 951         if (l < 5)
 952         {
 953                 LOG(1, s, t, "Short IPCP %d bytes\n", l);
 954                 STAT(tunnel_rx_errors);
 955                 return ;
 956         }
 957
 958         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 959         {
 960                 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
 961                 STAT(tunnel_rx_errors);
 962                 return ;
 963         }
 964         l = hl;
 965
 966         if (session[s].ppp.phase < Network)
 967         {
 968                 LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
 969                 return;
 970         }
 971
 972         LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
 973
 974         if (*p == ConfigAck)
 975         {
 976                 switch (session[s].ppp.ipcp)
 977                 {
 978                 case RequestSent:
 979                         initialise_restart_count(s, ipcp);
 980                         change_state(s, ipcp, AckReceived);
 981                         break;
 982
 983                 case AckReceived:
 984                 case Opened:
 985                         LOG(2, s, t, "IPCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
 986                         sendipcp(s, t);
 987                         change_state(s, ipcp, RequestSent);
 988                         break;
 989
 990                 case AckSent:
 991                         ipcp_open(s, t);
 992                         break;
 993
 994                 default:
 995                         LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
 996                 }
 997         }
 998         else if (*p == ConfigReq)
 999         {
1000                 uint8_t *response = 0;
1001                 uint8_t *o = p + 4;
1002                 int length = l - 4;
1003                 int gotip = 0;
1004                 in_addr_t addr;
1005
1006                 while (length > 2)
1007                 {
1008                         switch (*o)
1009                         {
1010                         case 3: // ip address
1011                                 gotip++; // seen address
1012                                 if (o[1] != 6 || o[1] > length) return;
1013
1014                                 addr = htonl(session[s].ip);
1015                                 if (memcmp(o + 2, &addr, (sizeof addr)))
1016                                 {
1017                                         uint8_t *oq = q;
1018                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1019                                         if (!q || (q != oq && *response == ConfigRej))
1020                                         {
1021                                                 sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
1022                                                 return;
1023                                         }
1024                                 }
1025
1026                                 break;
1027
1028                         case 129: // primary DNS
1029                                 if (o[1] != 6 || o[1] > length) return;
1030
1031                                 addr = htonl(session[s].dns1);
1032                                 if (memcmp(o + 2, &addr, (sizeof addr)))
1033                                 {
1034                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1035                                         if (!q) return;
1036                                 }
1037
1038                                 break;
1039
1040                         case 131: // secondary DNS
1041                                 if (o[1] != 6 || o[1] > length) return;
1042
1043                                 addr = htonl(session[s].dns2);
1044                                 if (memcmp(o + 2, &addr, sizeof(addr)))
1045                                 {
1046                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1047                                         if (!q) return;
1048                                 }
1049
1050                                 break;
1051
1052                         default:
1053                                 LOG(2, s, t, "    Rejecting PPP IPCP Option type %d\n", *o);
1054                                 q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
1055                                 if (!q) return;
1056                         }
1057
1058                         length -= o[1];
1059                         o += o[1];
1060                 }
1061
1062                 if (response)
1063                 {
1064                         l = q - response; // IPCP packet length
1065                         *((uint16_t *) (response + 2)) = htons(l); // update header
1066                 }
1067                 else if (gotip)
1068                 {
1069                         // Send packet back as ConfigAck
1070                         response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1071                         if (!response) return;
1072                         *response = ConfigAck;
1073                 }
1074                 else
1075                 {
1076                         LOG(1, s, t, "No IP in IPCP request\n");
1077                         STAT(tunnel_rx_errors);
1078                         return;
1079                 }
1080
1081                 switch (session[s].ppp.ipcp)
1082                 {
1083                 case Closed:
1084                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
1085                         if (!response) return;
1086                         *response = TerminateAck;
1087                         *((uint16_t *) (response + 2)) = htons(l = 4);
1088                         break;
1089
1090                 case Stopped:
1091                         initialise_restart_count(s, ipcp);
1092                         sendipcp(s, t);
1093                         if (*response == ConfigAck)
1094                                 change_state(s, ipcp, AckSent);
1095                         else
1096                                 change_state(s, ipcp, RequestSent);
1097
1098                         break;
1099
1100                 case RequestSent:
1101                         if (*response == ConfigAck)
1102                                 change_state(s, ipcp, AckSent);
1103
1104                         break;
1105
1106                 case AckReceived:
1107                         if (*response == ConfigAck)
1108                                 ipcp_open(s, t);
1109
1110                         break;
1111
1112                 case Opened:
1113                         initialise_restart_count(s, ipcp);
1114                         sendipcp(s, t);
1115                         /* fallthrough */
1116
1117                 case AckSent:
1118                         if (*response == ConfigAck)
1119                                 change_state(s, ipcp, AckSent);
1120                         else
1121                                 change_state(s, ipcp, RequestSent);
1122
1123                         break;
1124
1125                 default:
1126                         LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1127                         return;
1128                 }
1129
1130                 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
1131                 tunnelsend(b, l + (response - b), t);
1132         }
1133         else if (*p == TerminateReq)
1134         {
1135                 *p = TerminateAck;
1136                 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1137                 if (!q) return;
1138                 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
1139                 tunnelsend(b, l + (q - b), t);
1140                 change_state(s, ipcp, Stopped);
1141         }
1142         else if (*p != CodeRej)
1143         {
1144                 ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
1145         }
1146 }
1147
1148 static void ipv6cp_open(sessionidt s, tunnelidt t)
1149 {
1150         LOG(3, s, t, "IPV6CP: Opened\n");
1151
1152         change_state(s, ipv6cp, Opened);
1153         if (session[s].ipv6prefixlen)
1154                 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
1155
1156         // Send an initial RA (TODO: Should we send these regularly?)
1157         send_ipv6_ra(s, t, NULL);
1158 }
1159
1160 // Process IPV6CP messages
1161 void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1162 {
1163         uint8_t b[MAXETHER];
1164         uint8_t *q = 0;
1165         uint16_t hl;
1166
1167         CSTAT(processipv6cp);
1168
1169         LOG_HEX(5, "IPV6CP", p, l);
1170         if (l < 4)
1171         {
1172                 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
1173                 STAT(tunnel_rx_errors);
1174                 return ;
1175         }
1176
1177         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
1178         {
1179                 LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
1180                 STAT(tunnel_rx_errors);
1181                 return ;
1182         }
1183         l = hl;
1184
1185         if (session[s].ppp.phase < Network)
1186         {
1187                 LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1188                 return;
1189         }
1190
1191         LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
1192
1193         if (!session[s].ip)
1194         {
1195                 LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
1196                 return; // need IPCP to complete...
1197         }
1198
1199         if (*p == ConfigAck)
1200         {
1201                 switch (session[s].ppp.ipv6cp)
1202                 {
1203                 case RequestSent:
1204                         initialise_restart_count(s, ipv6cp);
1205                         change_state(s, ipv6cp, AckReceived);
1206                         break;
1207
1208                 case AckReceived:
1209                 case Opened:
1210                         LOG(2, s, t, "IPV6CP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
1211                         sendipv6cp(s, t);
1212                         change_state(s, ipv6cp, RequestSent);
1213                         break;
1214
1215                 case AckSent:
1216                         ipv6cp_open(s, t);
1217                         break;
1218
1219                 default:
1220                         LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1221                 }
1222         }
1223         else if (*p == ConfigReq)
1224         {
1225                 uint8_t *response = 0;
1226                 uint8_t *o = p + 4;
1227                 int length = l - 4;
1228                 int gotip = 0;
1229                 uint8_t ident[8];
1230
1231                 while (length > 2)
1232                 {
1233                         switch (*o)
1234                         {
1235                         case 1: // interface identifier
1236                                 gotip++; // seen address
1237                                 if (o[1] != 10 || o[1] > length) return;
1238
1239                                 *(uint32_t *) ident = htonl(session[s].ip);
1240                                 *(uint32_t *) (ident + 4) = 0;
1241
1242                                 if (memcmp(o + 2, ident, sizeof(ident)))
1243                                 {
1244                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
1245                                         if (!q) return;
1246                                 }
1247
1248                                 break;
1249
1250                         default:
1251                                 LOG(2, s, t, "    Rejecting PPP IPV6CP Option type %d\n", *o);
1252                                 q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
1253                                 if (!q) return;
1254                         }
1255
1256                         length -= o[1];
1257                         o += o[1];
1258                 }
1259
1260                 if (response)
1261                 {
1262                         l = q - response; // IPV6CP packet length
1263                         *((uint16_t *) (response + 2)) = htons(l); // update header
1264                 }
1265                 else if (gotip)
1266                 {
1267                         // Send packet back as ConfigAck
1268                         response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1269                         if (!response) return;
1270                         *response = ConfigAck;
1271                 }
1272                 else
1273                 {
1274                         LOG(1, s, t, "No interface identifier in IPV6CP request\n");
1275                         STAT(tunnel_rx_errors);
1276                         return;
1277                 }
1278
1279                 switch (session[s].ppp.ipv6cp)
1280                 {
1281                 case Closed:
1282                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
1283                         if (!response) return;
1284                         *response = TerminateAck;
1285                         *((uint16_t *) (response + 2)) = htons(l = 4);
1286                         break;
1287
1288                 case Stopped:
1289                         initialise_restart_count(s, ipv6cp);
1290                         sendipv6cp(s, t);
1291                         if (*response == ConfigAck)
1292                                 change_state(s, ipv6cp, AckSent);
1293                         else
1294                                 change_state(s, ipv6cp, RequestSent);
1295
1296                         break;
1297
1298                 case RequestSent:
1299                         if (*response == ConfigAck)
1300                                 change_state(s, ipv6cp, AckSent);
1301
1302                         break;
1303
1304                 case AckReceived:
1305                         if (*response == ConfigAck)
1306                                 ipv6cp_open(s, t);
1307
1308                         break;
1309
1310                 case Opened:
1311                         initialise_restart_count(s, ipv6cp);
1312                         sendipv6cp(s, t);
1313                         /* fallthrough */
1314
1315                 case AckSent:
1316                         if (*response == ConfigAck)
1317                                 change_state(s, ipv6cp, AckSent);
1318                         else
1319                                 change_state(s, ipv6cp, RequestSent);
1320
1321                         break;
1322
1323                 default:
1324                         LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1325                         return;
1326                 }
1327
1328                 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
1329                 tunnelsend(b, l + (response - b), t);
1330         }
1331         else if (*p == TerminateReq)
1332         {
1333                 *p = TerminateAck;
1334                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
1335                 if (!q) return;
1336                 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
1337                 tunnelsend(b, l + (q - b), t);
1338                 change_state(s, ipv6cp, Stopped);
1339         }
1340         else if (*p != CodeRej)
1341         {
1342                 ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
1343         }
1344 }
1345
1346 // process IP packet received
1347 //
1348 // This MUST be called with at least 4 byte behind 'p'.
1349 // (i.e. this routine writes to p[-4]).
1350 void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1351 {
1352         in_addr_t ip;
1353
1354         CSTAT(processipin);
1355
1356         LOG_HEX(5, "IP", p, l);
1357
1358         if (l < 20)
1359         {
1360                 LOG(1, s, t, "IP packet too short %d\n", l);
1361                 STAT(tunnel_rx_errors);
1362                 return ;
1363         }
1364
1365         ip = ntohl(*(uint32_t *)(p + 12));
1366
1367         if (l > MAXETHER)
1368         {
1369                 LOG(1, s, t, "IP packet too long %d\n", l);
1370                 STAT(tunnel_rx_errors);
1371                 return ;
1372         }
1373
1374         if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
1375                 return;
1376
1377         // no spoof (do sessionbyip to handled statically routed subnets)
1378         if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
1379         {
1380                 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
1381                 return;
1382         }
1383
1384         // run access-list if any
1385         if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
1386                 return;
1387
1388         // adjust MSS on SYN and SYN,ACK packets with options
1389         if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
1390         {
1391                 int ihl = (p[0] & 0xf) * 4; // length of IP header
1392                 if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
1393                         adjust_tcp_mss(s, t, p, l, p + ihl);
1394         }
1395
1396         // Add on the tun header
1397         p -= 4;
1398         *(uint32_t *) p = htonl(PKTIP);
1399         l += 4;
1400
1401         // Are we throttled and a slave?
1402         if (session[s].tbf_in && !config->cluster_iam_master) {
1403                 // Pass it to the master for handling.
1404                 master_throttle_packet(session[s].tbf_in, p, l);
1405                 return;
1406         }
1407
1408         // Are we throttled and a master??
1409         if (session[s].tbf_in && config->cluster_iam_master) {
1410                 // Actually handle the throttled packets.
1411                 tbf_queue_packet(session[s].tbf_in, p, l);
1412                 return;
1413         }
1414
1415         // send to ethernet
1416         if (tun_write(p, l) < 0)
1417         {
1418                 STAT(tun_tx_errors);
1419                 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1420                         l, strerror(errno), tunfd, p);
1421
1422                 return;
1423         }
1424
1425         p += 4;
1426         l -= 4;
1427
1428         if (session[s].snoop_ip && session[s].snoop_port)
1429         {
1430                 // Snooping this session
1431                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1432         }
1433
1434         increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1435         session[s].cin_delta += l;
1436         session[s].pin++;
1437
1438         sess_local[s].cin += l;
1439         sess_local[s].pin++;
1440
1441         eth_tx += l;
1442
1443         STAT(tun_tx_packets);
1444         INC_STAT(tun_tx_bytes, l);
1445 }
1446
1447 // process IPv6 packet received
1448 //
1449 // This MUST be called with at least 4 byte behind 'p'.
1450 // (i.e. this routine writes to p[-4]).
1451 void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1452 {
1453         struct in6_addr ip;
1454         in_addr_t ipv4;
1455
1456         CSTAT(processipv6in);
1457
1458         LOG_HEX(5, "IPv6", p, l);
1459
1460         ip = *(struct in6_addr *) (p + 8);
1461         ipv4 = ntohl(*(uint32_t *)(p + 16));
1462
1463         if (l > MAXETHER)
1464         {
1465                 LOG(1, s, t, "IP packet too long %d\n", l);
1466                 STAT(tunnel_rx_errors);
1467                 return ;
1468         }
1469
1470         if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
1471                 return;
1472
1473         // no spoof
1474         if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1475         {
1476                 char str[INET6_ADDRSTRLEN];
1477                 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1478                                 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1479                 return;
1480         }
1481
1482         // Check if it's a Router Solicition message.
1483         if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1484                         *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1485                         *(uint32_t *)(p + 34) == 0 &&
1486                         *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1487                 LOG(3, s, t, "Got IPv6 RS\n");
1488                 send_ipv6_ra(s, t, &ip);
1489                 return;
1490         }
1491
1492         // Add on the tun header
1493         p -= 4;
1494         *(uint32_t *) p = htonl(PKTIPV6);
1495         l += 4;
1496
1497         // Are we throttled and a slave?
1498         if (session[s].tbf_in && !config->cluster_iam_master) {
1499                 // Pass it to the master for handling.
1500                 master_throttle_packet(session[s].tbf_in, p, l);
1501                 return;
1502         }
1503
1504         // Are we throttled and a master??
1505         if (session[s].tbf_in && config->cluster_iam_master) {
1506                 // Actually handle the throttled packets.
1507                 tbf_queue_packet(session[s].tbf_in, p, l);
1508                 return;
1509         }
1510
1511         // send to ethernet
1512         if (tun_write(p, l) < 0)
1513         {
1514                 STAT(tun_tx_errors);
1515                 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1516                         l, strerror(errno), tunfd, p);
1517
1518                 return;
1519         }
1520
1521         p += 4;
1522         l -= 4;
1523
1524         if (session[s].snoop_ip && session[s].snoop_port)
1525         {
1526                 // Snooping this session
1527                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1528         }
1529
1530         increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1531         session[s].cin_delta += l;
1532         session[s].pin++;
1533
1534         sess_local[s].cin += l;
1535         sess_local[s].pin++;
1536
1537         eth_tx += l;
1538
1539         STAT(tun_tx_packets);
1540         INC_STAT(tun_tx_bytes, l);
1541 }
1542
1543 //
1544 // Helper routine for the TBF filters.
1545 // Used to send queued data in from the user.
1546 //
1547 void send_ipin(sessionidt s, uint8_t *buf, int len)
1548 {
1549         LOG_HEX(5, "IP in throttled", buf, len);
1550
1551         if (write(tunfd, buf, len) < 0)
1552         {
1553                 STAT(tun_tx_errors);
1554                 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1555                         len, strerror(errno), tunfd, buf);
1556
1557                 return;
1558         }
1559
1560         buf += 4;
1561         len -= 4;
1562
1563         if (session[s].snoop_ip && session[s].snoop_port)
1564         {
1565                 // Snooping this session
1566                 snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
1567         }
1568
1569         // Increment packet counters
1570         increment_counter(&session[s].cin, &session[s].cin_wrap, len);
1571         session[s].cin_delta += len;
1572         session[s].pin++;
1573
1574         sess_local[s].cin += len;
1575         sess_local[s].pin++;
1576
1577         eth_tx += len;
1578
1579         STAT(tun_tx_packets);
1580         INC_STAT(tun_tx_bytes, len - 4);
1581 }
1582
1583
1584 // Process CCP messages
1585 void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1586 {
1587         uint8_t b[MAXETHER];
1588         uint8_t *q;
1589
1590         CSTAT(processccp);
1591
1592         LOG_HEX(5, "CCP", p, l);
1593
1594         if (session[s].ppp.phase < Network)
1595         {
1596                 LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1597                 return;
1598         }
1599
1600         if (l < 1)
1601         {
1602                 LOG(1, s, t, "Short CCP packet\n");
1603                 STAT(tunnel_rx_errors);
1604         }
1605
1606         LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
1607         if (*p == ConfigAck)
1608         {
1609                 switch (session[s].ppp.ccp)
1610                 {
1611                 case RequestSent:
1612                         initialise_restart_count(s, ccp);
1613                         change_state(s, ccp, AckReceived);
1614                         break;
1615
1616                 case AckReceived:
1617                 case Opened:
1618                         LOG(2, s, t, "CCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
1619                         sendccp(s, t);
1620                         change_state(s, ccp, RequestSent);
1621                         break;
1622
1623                 case AckSent:
1624                         LOG(3, s, t, "CCP: Opened\n");
1625                         change_state(s, ccp, Opened);
1626                         break;
1627
1628                 default:
1629                         LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1630                 }
1631         }
1632         else if (*p == ConfigReq)
1633         {
1634                 if (l < 6) // accept no compression
1635                         *p = ConfigAck;
1636                 else // compression requested--reject
1637                         *p = ConfigRej;
1638
1639                 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1640                 if (!q) return;
1641
1642                 switch (session[s].ppp.ccp)
1643                 {
1644                 case Closed:
1645                         q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
1646                         if (!q) return;
1647                         *q = TerminateAck;
1648                         *((uint16_t *) (q + 2)) = htons(l = 4);
1649                         break;
1650
1651                 case Stopped:
1652                         initialise_restart_count(s, ccp);
1653                         sendccp(s, t);
1654                         if (*q == ConfigAck)
1655                                 change_state(s, ccp, AckSent);
1656                         else
1657                                 change_state(s, ccp, RequestSent);
1658
1659                         break;
1660
1661                 case RequestSent:
1662                         if (*q == ConfigAck)
1663                                 change_state(s, ccp, AckSent);
1664
1665                         break;
1666
1667                 case AckReceived:
1668                         if (*q == ConfigAck)
1669                                 change_state(s, ccp, Opened);
1670
1671                         break;
1672
1673                 case Opened:
1674                         initialise_restart_count(s, ccp);
1675                         sendccp(s, t);
1676                         /* fallthrough */
1677
1678                 case AckSent:
1679                         if (*q == ConfigAck)
1680                                 change_state(s, ccp, AckSent);
1681                         else
1682                                 change_state(s, ccp, RequestSent);
1683
1684                         break;
1685
1686                 default:
1687                         LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1688                         return;
1689                 }
1690
1691                 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1692                 tunnelsend(b, l + (q - b), t);
1693         }
1694         else if (*p == TerminateReq)
1695         {
1696                 *p = TerminateAck;
1697                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPCCP);
1698                 if (!q) return;
1699                 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1700                 tunnelsend(b, l + (q - b), t);
1701                 change_state(s, ccp, Stopped);
1702         }
1703         else if (*p != CodeRej)
1704         {
1705                 ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
1706         }
1707 }
1708
1709 // send a CHAP challenge
1710 void sendchap(sessionidt s, tunnelidt t)
1711 {
1712         uint8_t b[MAXETHER];
1713         uint16_t r;
1714         uint8_t *q;
1715
1716         CSTAT(sendchap);
1717
1718         r = radiusnew(s);
1719         if (!r)
1720         {
1721                 LOG(1, s, t, "No RADIUS to send challenge\n");
1722                 STAT(tunnel_tx_errors);
1723                 return;
1724         }
1725
1726         LOG(1, s, t, "Send CHAP challenge\n");
1727
1728         radius[r].chap = 1;             // CHAP not PAP
1729         radius[r].id++;
1730         if (radius[r].state != RADIUSCHAP)
1731                 radius[r].try = 0;
1732
1733         radius[r].state = RADIUSCHAP;
1734         radius[r].retry = backoff(radius[r].try++);
1735         if (radius[r].try > 5)
1736         {
1737                 sessionshutdown(s, "CHAP timeout.", 3, 0);
1738                 STAT(tunnel_tx_errors);
1739                 return ;
1740         }
1741         q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
1742         if (!q) return;
1743
1744         *q = 1;                                 // challenge
1745         q[1] = radius[r].id;                    // ID
1746         q[4] = 16;                              // value size (size of challenge)
1747         memcpy(q + 5, radius[r].auth, 16);      // challenge
1748         strcpy((char *) q + 21, hostname);      // our name
1749         *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1750         tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1751 }
1752
1753 // fill in a L2TP message with a PPP frame,
1754 // copies existing PPP message and changes magic number if seen
1755 // returns start of PPP frame
1756 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
1757 {
1758         if (size < 12) // Need more space than this!!
1759         {
1760                 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1761                 return NULL;
1762         }
1763
1764         *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1765         *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1766         *(uint16_t *) (b + 4) = htons(session[s].far); // session
1767         b += 6;
1768         if (mtype == PPPLCP || !(session[s].flags & SESSION_ACFC))
1769         {
1770                 *(uint16_t *) b = htons(0xFF03); // HDLC header
1771                 b += 2;
1772         }
1773         if (mtype < 0x100 && session[s].flags & SESSION_PFC)
1774                 *b++ = mtype;
1775         else
1776         {
1777                 *(uint16_t *) b = htons(mtype);
1778                 b += 2;
1779         }
1780
1781         if (l + 12 > size)
1782         {
1783                 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1784                 return NULL;
1785         }
1786
1787         if (p && l)
1788                 memcpy(b, p, l);
1789
1790         return b;
1791 }
1792
1793 static int add_lcp_auth(uint8_t *b, int size, int authtype)
1794 {
1795         int len = 0;
1796         if ((authtype == AUTHCHAP && size < 5) || size < 4)
1797                 return 0;
1798
1799         *b++ = 3; // Authentication-Protocol
1800         if (authtype == AUTHCHAP)
1801         {
1802                 len = *b++ = 5; // length
1803                 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1804                 *b++ = 5; // MD5
1805         }
1806         else if (authtype == AUTHPAP)
1807         {
1808                 len = *b++ = 4; // length
1809                 *(uint16_t *) b = htons(PPPPAP); b += 2;
1810         }
1811         else
1812         {
1813                 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1814         }
1815
1816         return len;
1817 }
1818
1819 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1820 void sendlcp(sessionidt s, tunnelidt t)
1821 {
1822         uint8_t b[500], *q, *l;
1823         int authtype = sess_local[s].lcp_authtype;
1824
1825         if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
1826                 return;
1827
1828         LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
1829             authtype ? " (" : "",
1830             authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
1831             authtype ? ")" : "");
1832
1833         l = q;
1834         *l++ = ConfigReq;
1835         *l++ = ++sess_local[s].lcp_ident; // ID
1836
1837         l += 2; //Save space for length
1838
1839         if (sess_local[s].ppp_mru)
1840         {
1841                 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1842                 *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
1843         }
1844
1845         if (authtype)
1846                 l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1847
1848         *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1849         *(uint32_t *) l = htonl(session[s].magic);
1850         l += 4;
1851
1852         *(uint16_t *)(q + 2) = htons(l - q); // Length
1853
1854         LOG_HEX(5, "PPPLCP", q, l - q);
1855         if (config->debug > 3) dumplcp(q, l - q);
1856
1857         tunnelsend(b, (l - b), t);
1858         restart_timer(s, lcp);
1859 }
1860
1861 // Send CCP request for no compression
1862 void sendccp(sessionidt s, tunnelidt t)
1863 {
1864         uint8_t b[500], *q;
1865
1866         if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
1867                 return;
1868
1869         LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
1870
1871         *q = ConfigReq;
1872         *(q + 1) = ++sess_local[s].lcp_ident; // ID
1873         *(uint16_t *)(q + 2) = htons(4); // Length
1874
1875         LOG_HEX(5, "PPPCCP", q, 4);
1876         tunnelsend(b, (q - b) + 4 , t);
1877         restart_timer(s, ccp);
1878 }
1879
1880 // Reject unknown/unconfigured protocols
1881 void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
1882 {
1883
1884         uint8_t buf[MAXETHER];
1885         uint8_t *q;
1886         int mru = session[s].mru;
1887         if (mru < MINMTU) mru = MINMTU;
1888         if (mru > sizeof(buf)) mru = sizeof(buf);
1889
1890         l += 6;
1891         if (l > mru) l = mru;
1892
1893         q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
1894         if (!q) return;
1895
1896         *q = ProtocolRej;
1897         *(q + 1) = ++sess_local[s].lcp_ident;
1898         *(uint16_t *)(q + 2) = htons(l);
1899         *(uint16_t *)(q + 4) = htons(proto);
1900         memcpy(q + 6, p, l - 6);
1901
1902         if (proto == PPPIPV6CP)
1903                 LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
1904         else
1905                 LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
1906
1907         tunnelsend(buf, l + (q - buf), t);
1908 }