ppp.c

   1 // L2TPNS PPP Stuff
   2
   3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.88 2005/12/07 05:21:37 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 ? 4 : 3, s, t, "LCP: recv %s\n", ppp_code(*p));
 503         if (config->debug > 3) dumplcp(p, l);
 504
 505         if (*p == ConfigAck)
 506         {
 507                 int x = l - 4;
 508                 uint8_t *o = (p + 4);
 509                 int authtype = 0;
 510
 511                 while (x > 2)
 512                 {
 513                         int type = o[0];
 514                         int length = o[1];
 515
 516                         if (length == 0 || type == 0 || x < length) break;
 517                         switch (type)
 518                         {
 519                                 case 3: // Authentication-Protocol
 520                                         {
 521                                                 int proto = ntohs(*(uint16_t *)(o + 2));
 522                                                 if (proto == PPPPAP)
 523                                                         authtype = AUTHPAP;
 524                                                 else if (proto == PPPCHAP && *(o + 4) == 5)
 525                                                         authtype = AUTHCHAP;
 526                                         }
 527
 528                                         break;
 529                         }
 530                         x -= length;
 531                         o += length;
 532                 }
 533
 534                 if (!session[s].ip && authtype)
 535                         sess_local[s].lcp_authtype = authtype;
 536
 537                 switch (session[s].ppp.lcp)
 538                 {
 539                 case RequestSent:
 540                         initialise_restart_count(s, lcp);
 541                         change_state(s, lcp, AckReceived);
 542                         break;
 543
 544                 case AckReceived:
 545                 case Opened:
 546                         LOG(2, s, t, "LCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
 547                         if (session[s].ppp.lcp == Opened)
 548                                 lcp_restart(s);
 549
 550                         sendlcp(s, t);
 551                         change_state(s, lcp, RequestSent);
 552                         break;
 553
 554                 case AckSent:
 555                         lcp_open(s, t);
 556                         break;
 557
 558                 default:
 559                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 560                 }
 561         }
 562         else if (*p == ConfigReq)
 563         {
 564                 int x = l - 4;
 565                 uint8_t *o = (p + 4);
 566                 uint8_t *response = 0;
 567                 static uint8_t asyncmap[4] = { 0, 0, 0, 0 }; // all zero
 568                 static uint8_t authproto[5];
 569
 570                 while (x > 2)
 571                 {
 572                         int type = o[0];
 573                         int length = o[1];
 574
 575                         if (length == 0 || type == 0 || x < length) break;
 576                         switch (type)
 577                         {
 578                                 case 1: // Maximum-Receive-Unit
 579                                         {
 580                                                 uint16_t mru = ntohs(*(uint16_t *)(o + 2));
 581                                                 if (mru >= MINMTU)
 582                                                 {
 583                                                         session[s].mru = mru;
 584                                                         break;
 585                                                 }
 586
 587                                                 LOG(3, s, t, "    Remote requesting MRU of %u.  Rejecting.\n", mru);
 588                                                 mru = htons(MRU);
 589                                                 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, (uint8_t *) &mru, sizeof(mru));
 590                                         }
 591                                         break;
 592
 593                                 case 2: // Async-Control-Character-Map
 594                                         if (!ntohl(*(uint32_t *)(o + 2))) // all bits zero is OK
 595                                                 break;
 596
 597                                         LOG(3, s, t, "    Remote requesting asyncmap.  Rejecting.\n");
 598                                         q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, asyncmap, sizeof(asyncmap));
 599                                         break;
 600
 601                                 case 3: // Authentication-Protocol
 602                                         {
 603                                                 int proto = ntohs(*(uint16_t *)(o + 2));
 604                                                 char proto_name[] = "0x0000";
 605                                                 int alen;
 606
 607                                                 if (proto == PPPPAP)
 608                                                 {
 609                                                         if (config->radius_authtypes & AUTHPAP)
 610                                                         {
 611                                                                 sess_local[s].lcp_authtype = AUTHPAP;
 612                                                                 break;
 613                                                         }
 614
 615                                                         strcpy(proto_name, "PAP");
 616                                                 }
 617                                                 else if (proto == PPPCHAP)
 618                                                 {
 619                                                         if (config->radius_authtypes & AUTHCHAP
 620                                                             && *(o + 4) == 5) // MD5
 621                                                         {
 622                                                                 sess_local[s].lcp_authtype = AUTHCHAP;
 623                                                                 break;
 624                                                         }
 625
 626                                                         strcpy(proto_name, "CHAP");
 627                                                 }
 628                                                 else
 629                                                         sprintf(proto_name, "%#4.4x", proto);
 630
 631                                                 LOG(3, s, t, "    Remote requesting %s authentication.  Rejecting.\n", proto_name);
 632
 633                                                 alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authprefer);
 634                                                 if (alen < 2) break; // paranoia
 635
 636                                                 q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
 637                                                 if (q && *response == ConfigNak &&
 638                                                         config->radius_authtypes != config->radius_authprefer)
 639                                                 {
 640                                                         // alternate type
 641                                                         alen = add_lcp_auth(authproto, sizeof(authproto), config->radius_authtypes & ~config->radius_authprefer);
 642                                                         if (alen < 2) break;
 643                                                         q = ppp_conf_nak(s, b, sizeof(b), PPPLCP, &response, q, p, o, authproto + 2, alen - 2);
 644                                                 }
 645
 646                                                 break;
 647                                         }
 648                                         break;
 649
 650                                 case 5: // Magic-Number
 651                                         magicno = ntohl(*(uint32_t *)(o + 2));
 652                                         break;
 653
 654                                 case 4: // Quality-Protocol
 655                                 case 7: // Protocol-Field-Compression
 656                                 case 8: // Address-And-Control-Field-Compression
 657                                         break;
 658
 659                                 default: // Reject any unknown options
 660                                         LOG(3, s, t, "    Rejecting unknown PPP LCP option %d\n", type);
 661                                         q = ppp_conf_rej(s, b, sizeof(b), PPPLCP, &response, q, p, o);
 662                         }
 663                         x -= length;
 664                         o += length;
 665                 }
 666
 667                 if (response)
 668                 {
 669                         l = q - response; // LCP packet length
 670                         *((uint16_t *) (response + 2)) = htons(l); // update header
 671                 }
 672                 else
 673                 {
 674                         // Send packet back as ConfigAck
 675                         response = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
 676                         if (!response) return;
 677                         *response = ConfigAck;
 678                 }
 679
 680                 switch (session[s].ppp.lcp)
 681                 {
 682                 case Closed:
 683                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
 684                         if (!response) return;
 685                         *response = TerminateAck;
 686                         *((uint16_t *) (response + 2)) = htons(l = 4);
 687                         break;
 688
 689                 case Stopped:
 690                         initialise_restart_count(s, lcp);
 691                         sendlcp(s, t);
 692                         if (*response == ConfigAck)
 693                                 change_state(s, lcp, AckSent);
 694                         else
 695                                 change_state(s, lcp, RequestSent);
 696
 697                         break;
 698
 699                 case RequestSent:
 700                         if (*response == ConfigAck)
 701                                 change_state(s, lcp, AckSent);
 702
 703                         break;
 704
 705                 case AckReceived:
 706                         if (*response == ConfigAck)
 707                                 lcp_open(s, t);
 708
 709                         break;
 710
 711                 case Opened:
 712                         lcp_restart(s);
 713                         sendlcp(s, t);
 714                         /* fallthrough */
 715
 716                 case AckSent:
 717                         if (*response == ConfigAck)
 718                                 change_state(s, lcp, AckSent);
 719                         else
 720                                 change_state(s, lcp, RequestSent);
 721
 722                         break;
 723
 724                 default:
 725                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 726                         return;
 727                 }
 728
 729                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
 730                 if (config->debug > 3) dumplcp(response, l);
 731
 732                 tunnelsend(b, l + (response - b), t);
 733         }
 734         else if (*p == ConfigNak || *p == ConfigRej)
 735         {
 736                 int x = l - 4;
 737                 uint8_t *o = (p + 4);
 738                 int authtype = -1;
 739
 740                 while (x > 2)
 741                 {
 742                         int type = o[0];
 743                         int length = o[1];
 744
 745                         if (length == 0 || type == 0 || x < length) break;
 746                         switch (type)
 747                         {
 748                                 case 1: // Maximum-Receive-Unit
 749                                         if (*p == ConfigNak)
 750                                         {
 751                                                 sess_local[s].ppp_mru = ntohs(*(uint16_t *)(o + 2));
 752                                                 LOG(3, s, t, "    Remote requested MRU of %u\n", sess_local[s].ppp_mru);
 753                                         }
 754                                         else
 755                                         {
 756                                                 sess_local[s].ppp_mru = 0;
 757                                                 LOG(3, s, t, "    Remote rejected MRU negotiation\n");
 758                                         }
 759
 760                                         break;
 761
 762                                 case 3: // Authentication-Protocol
 763                                         if (authtype > 0)
 764                                                 break;
 765
 766                                         if (*p == ConfigNak)
 767                                         {
 768                                                 int proto = ntohs(*(uint16_t *)(o + 2));
 769                                                 if (proto == PPPPAP)
 770                                                 {
 771                                                         authtype = config->radius_authtypes & AUTHPAP;
 772                                                         LOG(3, s, t, "    Remote requested PAP authentication...%sing\n",
 773                                                                 authtype ? "accept" : "reject");
 774                                                 }
 775                                                 else if (proto == PPPCHAP && *(o + 4) == 5)
 776                                                 {
 777                                                         authtype = config->radius_authtypes & AUTHCHAP;
 778                                                         LOG(3, s, t, "    Remote requested CHAP authentication...%sing\n",
 779                                                                 authtype ? "accept" : "reject");
 780                                                 }
 781                                                 else
 782                                                 {
 783                                                         LOG(3, s, t, "    Rejecting unsupported authentication %#4x\n",
 784                                                                 proto);
 785                                                 }
 786                                         }
 787                                         else
 788                                         {
 789                                                 LOG(2, s, t, "LCP: remote rejected auth negotiation\n");
 790                                                 authtype = 0; // shutdown
 791                                         }
 792
 793                                         break;
 794
 795                                 default:
 796                                         LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
 797                                         break;
 798                         }
 799                         x -= length;
 800                         o += length;
 801                 }
 802
 803                 if (!authtype)
 804                 {
 805                         sessionshutdown(s, "Unsupported authentication.", 3, 0);
 806                         return;
 807                 }
 808
 809                 if (authtype > 0)
 810                         sess_local[s].lcp_authtype = authtype;
 811
 812                 switch (session[s].ppp.lcp)
 813                 {
 814                 case Closed:
 815                 case Stopped:
 816                         {
 817                                 uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
 818                                 if (!response) return;
 819                                 *response = TerminateAck;
 820                                 *((uint16_t *) (response + 2)) = htons(l = 4);
 821
 822                                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
 823                                 if (config->debug > 3) dumplcp(response, l);
 824
 825                                 tunnelsend(b, l + (response - b), t);
 826                         }
 827                         break;
 828
 829                 case RequestSent:
 830                 case AckSent:
 831                         initialise_restart_count(s, lcp);
 832                         sendlcp(s, t);
 833                         break;
 834
 835                 case AckReceived:
 836                         LOG(2, s, t, "LCP: ConfigNak in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
 837                         sendlcp(s, t);
 838                         break;
 839
 840                 case Opened:
 841                         lcp_restart(s);
 842                         sendlcp(s, t);
 843                         break;
 844
 845                 default:
 846                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 847                         return;
 848                 }
 849         }
 850         else if (*p == TerminateReq)
 851         {
 852                 *p = TerminateAck;      // close
 853                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPLCP);
 854                 if (!q) return;
 855
 856                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
 857                 if (config->debug > 3) dumplcp(q, l);
 858
 859                 tunnelsend(b, l + (q - b), t); // send it
 860                 sessionshutdown(s, "Remote end closed connection.", 3, 0);
 861         }
 862         else if (*p == TerminateAck)
 863         {
 864                 sessionshutdown(s, "Connection closed.", 3, 0);
 865         }
 866         else if (*p == ProtocolRej)
 867         {
 868                 uint16_t proto = 0;
 869
 870                 if (l > 4)
 871                 {
 872                         proto = *(p+4);
 873                         if (l > 5 && !(proto & 1))
 874                         {
 875                                 proto <<= 8;
 876                                 proto |= *(p+5);
 877                         }
 878                 }
 879
 880                 if (proto == PPPIPV6CP)
 881                 {
 882                         LOG(3, s, t, "IPv6 rejected\n");
 883                         change_state(s, ipv6cp, Closed);
 884                 }
 885                 else
 886                 {
 887                         LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
 888                 }
 889         }
 890         else if (*p == EchoReq)
 891         {
 892                 *p = EchoReply;         // reply
 893                 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
 894                 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
 895                 if (!q) return;
 896
 897                 LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
 898                 if (config->debug > 3) dumplcp(q, l);
 899
 900                 tunnelsend(b, l + (q - b), t); // send it
 901         }
 902         else if (*p == EchoReply)
 903         {
 904                 // Ignore it, last_packet time is set earlier than this.
 905         }
 906         else if (*p != CodeRej)
 907         {
 908                 ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
 909         }
 910 }
 911
 912 static void ipcp_open(sessionidt s, tunnelidt t)
 913 {
 914         LOG(3, s, t, "IPCP: Opened, session is now active\n");
 915
 916         change_state(s, ipcp, Opened);
 917
 918         if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
 919         {
 920                 uint16_t r = radiusnew(s);
 921                 if (r)
 922                 {
 923                         radiussend(r, RADIUSSTART); // send radius start
 924
 925                         // don't send further Start records if IPCP is restarted
 926                         session[s].flags |= SESSION_STARTED;
 927                         cluster_send_session(s);
 928                 }
 929         }
 930
 931         // start IPv6 if configured and still in passive state
 932         if (session[s].ppp.ipv6cp == Stopped)
 933         {
 934                 sendipv6cp(s, t);
 935                 change_state(s, ipv6cp, RequestSent);
 936         }
 937 }
 938
 939 // Process IPCP messages
 940 void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 941 {
 942         uint8_t b[MAXETHER];
 943         uint8_t *q = 0;
 944         uint16_t hl;
 945
 946         CSTAT(processipcp);
 947
 948         LOG_HEX(5, "IPCP", p, l);
 949         if (l < 5)
 950         {
 951                 LOG(1, s, t, "Short IPCP %d bytes\n", l);
 952                 STAT(tunnel_rx_errors);
 953                 return ;
 954         }
 955
 956         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 957         {
 958                 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
 959                 STAT(tunnel_rx_errors);
 960                 return ;
 961         }
 962         l = hl;
 963
 964         if (session[s].ppp.phase < Network)
 965         {
 966                 LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
 967                 return;
 968         }
 969
 970         LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
 971
 972         if (*p == ConfigAck)
 973         {
 974                 switch (session[s].ppp.ipcp)
 975                 {
 976                 case RequestSent:
 977                         initialise_restart_count(s, ipcp);
 978                         change_state(s, ipcp, AckReceived);
 979                         break;
 980
 981                 case AckReceived:
 982                 case Opened:
 983                         LOG(2, s, t, "IPCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
 984                         sendipcp(s, t);
 985                         change_state(s, ipcp, RequestSent);
 986                         break;
 987
 988                 case AckSent:
 989                         ipcp_open(s, t);
 990                         break;
 991
 992                 default:
 993                         LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
 994                 }
 995         }
 996         else if (*p == ConfigReq)
 997         {
 998                 uint8_t *response = 0;
 999                 uint8_t *o = p + 4;
1000                 int length = l - 4;
1001                 int gotip = 0;
1002                 in_addr_t addr;
1003
1004                 while (length > 2)
1005                 {
1006                         switch (*o)
1007                         {
1008                         case 3: // ip address
1009                                 gotip++; // seen address
1010                                 if (o[1] != 6 || o[1] > length) return;
1011
1012                                 addr = htonl(session[s].ip);
1013                                 if (memcmp(o + 2, &addr, (sizeof addr)))
1014                                 {
1015                                         uint8_t *oq = q;
1016                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1017                                         if (!q || (q != oq && *response == ConfigRej))
1018                                         {
1019                                                 sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
1020                                                 return;
1021                                         }
1022                                 }
1023
1024                                 break;
1025
1026                         case 129: // primary DNS
1027                                 if (o[1] != 6 || o[1] > length) return;
1028
1029                                 addr = htonl(session[s].dns1);
1030                                 if (memcmp(o + 2, &addr, (sizeof addr)))
1031                                 {
1032                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1033                                         if (!q) return;
1034                                 }
1035
1036                                 break;
1037
1038                         case 131: // secondary DNS
1039                                 if (o[1] != 6 || o[1] > length) return;
1040
1041                                 addr = htonl(session[s].dns2);
1042                                 if (memcmp(o + 2, &addr, sizeof(addr)))
1043                                 {
1044                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1045                                         if (!q) return;
1046                                 }
1047
1048                                 break;
1049
1050                         default:
1051                                 LOG(2, s, t, "    Rejecting PPP IPCP Option type %d\n", *o);
1052                                 q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
1053                                 if (!q) return;
1054                         }
1055
1056                         length -= o[1];
1057                         o += o[1];
1058                 }
1059
1060                 if (response)
1061                 {
1062                         l = q - response; // IPCP packet length
1063                         *((uint16_t *) (response + 2)) = htons(l); // update header
1064                 }
1065                 else if (gotip)
1066                 {
1067                         // Send packet back as ConfigAck
1068                         response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1069                         if (!response) return;
1070                         *response = ConfigAck;
1071                 }
1072                 else
1073                 {
1074                         LOG(1, s, t, "No IP in IPCP request\n");
1075                         STAT(tunnel_rx_errors);
1076                         return;
1077                 }
1078
1079                 switch (session[s].ppp.ipcp)
1080                 {
1081                 case Closed:
1082                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
1083                         if (!response) return;
1084                         *response = TerminateAck;
1085                         *((uint16_t *) (response + 2)) = htons(l = 4);
1086                         break;
1087
1088                 case Stopped:
1089                         initialise_restart_count(s, ipcp);
1090                         sendipcp(s, t);
1091                         if (*response == ConfigAck)
1092                                 change_state(s, ipcp, AckSent);
1093                         else
1094                                 change_state(s, ipcp, RequestSent);
1095
1096                         break;
1097
1098                 case RequestSent:
1099                         if (*response == ConfigAck)
1100                                 change_state(s, ipcp, AckSent);
1101
1102                         break;
1103
1104                 case AckReceived:
1105                         if (*response == ConfigAck)
1106                                 ipcp_open(s, t);
1107
1108                         break;
1109
1110                 case Opened:
1111                         initialise_restart_count(s, ipcp);
1112                         sendipcp(s, t);
1113                         /* fallthrough */
1114
1115                 case AckSent:
1116                         if (*response == ConfigAck)
1117                                 change_state(s, ipcp, AckSent);
1118                         else
1119                                 change_state(s, ipcp, RequestSent);
1120
1121                         break;
1122
1123                 default:
1124                         LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1125                         return;
1126                 }
1127
1128                 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
1129                 tunnelsend(b, l + (response - b), t);
1130         }
1131         else if (*p == TerminateReq)
1132         {
1133                 *p = TerminateAck;
1134                 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1135                 if (!q) return;
1136                 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
1137                 tunnelsend(b, l + (q - b), t);
1138                 change_state(s, ipcp, Stopped);
1139         }
1140         else if (*p != CodeRej)
1141         {
1142                 ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
1143         }
1144 }
1145
1146 static void ipv6cp_open(sessionidt s, tunnelidt t)
1147 {
1148         LOG(3, s, t, "IPV6CP: Opened\n");
1149
1150         change_state(s, ipv6cp, Opened);
1151         if (session[s].ipv6prefixlen)
1152                 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
1153
1154         // Send an initial RA (TODO: Should we send these regularly?)
1155         send_ipv6_ra(s, t, NULL);
1156 }
1157
1158 // Process IPV6CP messages
1159 void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1160 {
1161         uint8_t b[MAXETHER];
1162         uint8_t *q = 0;
1163         uint16_t hl;
1164
1165         CSTAT(processipv6cp);
1166
1167         LOG_HEX(5, "IPV6CP", p, l);
1168         if (l < 4)
1169         {
1170                 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
1171                 STAT(tunnel_rx_errors);
1172                 return ;
1173         }
1174
1175         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
1176         {
1177                 LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
1178                 STAT(tunnel_rx_errors);
1179                 return ;
1180         }
1181         l = hl;
1182
1183         if (session[s].ppp.phase < Network)
1184         {
1185                 LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1186                 return;
1187         }
1188
1189         LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
1190
1191         if (!session[s].ip)
1192         {
1193                 LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
1194                 return; // need IPCP to complete...
1195         }
1196
1197         if (*p == ConfigAck)
1198         {
1199                 switch (session[s].ppp.ipv6cp)
1200                 {
1201                 case RequestSent:
1202                         initialise_restart_count(s, ipv6cp);
1203                         change_state(s, ipv6cp, AckReceived);
1204                         break;
1205
1206                 case AckReceived:
1207                 case Opened:
1208                         LOG(2, s, t, "IPV6CP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
1209                         sendipv6cp(s, t);
1210                         change_state(s, ipv6cp, RequestSent);
1211                         break;
1212
1213                 case AckSent:
1214                         ipv6cp_open(s, t);
1215                         break;
1216
1217                 default:
1218                         LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1219                 }
1220         }
1221         else if (*p == ConfigReq)
1222         {
1223                 uint8_t *response = 0;
1224                 uint8_t *o = p + 4;
1225                 int length = l - 4;
1226                 int gotip = 0;
1227                 uint8_t ident[8];
1228
1229                 while (length > 2)
1230                 {
1231                         switch (*o)
1232                         {
1233                         case 1: // interface identifier
1234                                 gotip++; // seen address
1235                                 if (o[1] != 10 || o[1] > length) return;
1236
1237                                 *(uint32_t *) ident = htonl(session[s].ip);
1238                                 *(uint32_t *) (ident + 4) = 0;
1239
1240                                 if (memcmp(o + 2, ident, sizeof(ident)))
1241                                 {
1242                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
1243                                         if (!q) return;
1244                                 }
1245
1246                                 break;
1247
1248                         default:
1249                                 LOG(2, s, t, "    Rejecting PPP IPV6CP Option type %d\n", *o);
1250                                 q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
1251                                 if (!q) return;
1252                         }
1253
1254                         length -= o[1];
1255                         o += o[1];
1256                 }
1257
1258                 if (response)
1259                 {
1260                         l = q - response; // IPV6CP packet length
1261                         *((uint16_t *) (response + 2)) = htons(l); // update header
1262                 }
1263                 else if (gotip)
1264                 {
1265                         // Send packet back as ConfigAck
1266                         response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1267                         if (!response) return;
1268                         *response = ConfigAck;
1269                 }
1270                 else
1271                 {
1272                         LOG(1, s, t, "No interface identifier in IPV6CP request\n");
1273                         STAT(tunnel_rx_errors);
1274                         return;
1275                 }
1276
1277                 switch (session[s].ppp.ipv6cp)
1278                 {
1279                 case Closed:
1280                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
1281                         if (!response) return;
1282                         *response = TerminateAck;
1283                         *((uint16_t *) (response + 2)) = htons(l = 4);
1284                         break;
1285
1286                 case Stopped:
1287                         initialise_restart_count(s, ipv6cp);
1288                         sendipv6cp(s, t);
1289                         if (*response == ConfigAck)
1290                                 change_state(s, ipv6cp, AckSent);
1291                         else
1292                                 change_state(s, ipv6cp, RequestSent);
1293
1294                         break;
1295
1296                 case RequestSent:
1297                         if (*response == ConfigAck)
1298                                 change_state(s, ipv6cp, AckSent);
1299
1300                         break;
1301
1302                 case AckReceived:
1303                         if (*response == ConfigAck)
1304                                 ipv6cp_open(s, t);
1305
1306                         break;
1307
1308                 case Opened:
1309                         initialise_restart_count(s, ipv6cp);
1310                         sendipv6cp(s, t);
1311                         /* fallthrough */
1312
1313                 case AckSent:
1314                         if (*response == ConfigAck)
1315                                 change_state(s, ipv6cp, AckSent);
1316                         else
1317                                 change_state(s, ipv6cp, RequestSent);
1318
1319                         break;
1320
1321                 default:
1322                         LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1323                         return;
1324                 }
1325
1326                 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
1327                 tunnelsend(b, l + (response - b), t);
1328         }
1329         else if (*p == TerminateReq)
1330         {
1331                 *p = TerminateAck;
1332                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
1333                 if (!q) return;
1334                 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
1335                 tunnelsend(b, l + (q - b), t);
1336                 change_state(s, ipv6cp, Stopped);
1337         }
1338         else if (*p != CodeRej)
1339         {
1340                 ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
1341         }
1342 }
1343
1344 // process IP packet received
1345 //
1346 // This MUST be called with at least 4 byte behind 'p'.
1347 // (i.e. this routine writes to p[-4]).
1348 void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1349 {
1350         in_addr_t ip;
1351
1352         CSTAT(processipin);
1353
1354         LOG_HEX(5, "IP", p, l);
1355
1356         if (l < 20)
1357         {
1358                 LOG(1, s, t, "IP packet too short %d\n", l);
1359                 STAT(tunnel_rx_errors);
1360                 return ;
1361         }
1362
1363         ip = ntohl(*(uint32_t *)(p + 12));
1364
1365         if (l > MAXETHER)
1366         {
1367                 LOG(1, s, t, "IP packet too long %d\n", l);
1368                 STAT(tunnel_rx_errors);
1369                 return ;
1370         }
1371
1372         if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
1373                 return;
1374
1375         // no spoof (do sessionbyip to handled statically routed subnets)
1376         if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
1377         {
1378                 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
1379                 return;
1380         }
1381
1382         // run access-list if any
1383         if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
1384                 return;
1385
1386         // adjust MSS on SYN and SYN,ACK packets with options
1387         if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
1388         {
1389                 int ihl = (p[0] & 0xf) * 4; // length of IP header
1390                 if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
1391                         adjust_tcp_mss(s, t, p, l, p + ihl);
1392         }
1393
1394         // Add on the tun header
1395         p -= 4;
1396         *(uint32_t *) p = htonl(PKTIP);
1397         l += 4;
1398
1399         // Are we throttled and a slave?
1400         if (session[s].tbf_in && !config->cluster_iam_master) {
1401                 // Pass it to the master for handling.
1402                 master_throttle_packet(session[s].tbf_in, p, l);
1403                 return;
1404         }
1405
1406         // Are we throttled and a master??
1407         if (session[s].tbf_in && config->cluster_iam_master) {
1408                 // Actually handle the throttled packets.
1409                 tbf_queue_packet(session[s].tbf_in, p, l);
1410                 return;
1411         }
1412
1413         // send to ethernet
1414         if (tun_write(p, l) < 0)
1415         {
1416                 STAT(tun_tx_errors);
1417                 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1418                         l, strerror(errno), tunfd, p);
1419
1420                 return;
1421         }
1422
1423         p += 4;
1424         l -= 4;
1425
1426         if (session[s].snoop_ip && session[s].snoop_port)
1427         {
1428                 // Snooping this session
1429                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1430         }
1431
1432         increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1433         session[s].cin_delta += l;
1434         session[s].pin++;
1435
1436         sess_local[s].cin += l;
1437         sess_local[s].pin++;
1438
1439         eth_tx += l;
1440
1441         STAT(tun_tx_packets);
1442         INC_STAT(tun_tx_bytes, l);
1443 }
1444
1445 // process IPv6 packet received
1446 //
1447 // This MUST be called with at least 4 byte behind 'p'.
1448 // (i.e. this routine writes to p[-4]).
1449 void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1450 {
1451         struct in6_addr ip;
1452         in_addr_t ipv4;
1453
1454         CSTAT(processipv6in);
1455
1456         LOG_HEX(5, "IPv6", p, l);
1457
1458         ip = *(struct in6_addr *) (p + 8);
1459         ipv4 = ntohl(*(uint32_t *)(p + 16));
1460
1461         if (l > MAXETHER)
1462         {
1463                 LOG(1, s, t, "IP packet too long %d\n", l);
1464                 STAT(tunnel_rx_errors);
1465                 return ;
1466         }
1467
1468         if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
1469                 return;
1470
1471         // no spoof
1472         if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1473         {
1474                 char str[INET6_ADDRSTRLEN];
1475                 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1476                                 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1477                 return;
1478         }
1479
1480         // Check if it's a Router Solicition message.
1481         if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1482                         *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1483                         *(uint32_t *)(p + 34) == 0 &&
1484                         *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1485                 LOG(3, s, t, "Got IPv6 RS\n");
1486                 send_ipv6_ra(s, t, &ip);
1487                 return;
1488         }
1489
1490         // Add on the tun header
1491         p -= 4;
1492         *(uint32_t *) p = htonl(PKTIPV6);
1493         l += 4;
1494
1495         // Are we throttled and a slave?
1496         if (session[s].tbf_in && !config->cluster_iam_master) {
1497                 // Pass it to the master for handling.
1498                 master_throttle_packet(session[s].tbf_in, p, l);
1499                 return;
1500         }
1501
1502         // Are we throttled and a master??
1503         if (session[s].tbf_in && config->cluster_iam_master) {
1504                 // Actually handle the throttled packets.
1505                 tbf_queue_packet(session[s].tbf_in, p, l);
1506                 return;
1507         }
1508
1509         // send to ethernet
1510         if (tun_write(p, l) < 0)
1511         {
1512                 STAT(tun_tx_errors);
1513                 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1514                         l, strerror(errno), tunfd, p);
1515
1516                 return;
1517         }
1518
1519         p += 4;
1520         l -= 4;
1521
1522         if (session[s].snoop_ip && session[s].snoop_port)
1523         {
1524                 // Snooping this session
1525                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1526         }
1527
1528         increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1529         session[s].cin_delta += l;
1530         session[s].pin++;
1531
1532         sess_local[s].cin += l;
1533         sess_local[s].pin++;
1534
1535         eth_tx += l;
1536
1537         STAT(tun_tx_packets);
1538         INC_STAT(tun_tx_bytes, l);
1539 }
1540
1541 //
1542 // Helper routine for the TBF filters.
1543 // Used to send queued data in from the user.
1544 //
1545 void send_ipin(sessionidt s, uint8_t *buf, int len)
1546 {
1547         LOG_HEX(5, "IP in throttled", buf, len);
1548
1549         if (write(tunfd, buf, len) < 0)
1550         {
1551                 STAT(tun_tx_errors);
1552                 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1553                         len, strerror(errno), tunfd, buf);
1554
1555                 return;
1556         }
1557
1558         buf += 4;
1559         len -= 4;
1560
1561         if (session[s].snoop_ip && session[s].snoop_port)
1562         {
1563                 // Snooping this session
1564                 snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
1565         }
1566
1567         // Increment packet counters
1568         increment_counter(&session[s].cin, &session[s].cin_wrap, len);
1569         session[s].cin_delta += len;
1570         session[s].pin++;
1571
1572         sess_local[s].cin += len;
1573         sess_local[s].pin++;
1574
1575         eth_tx += len;
1576
1577         STAT(tun_tx_packets);
1578         INC_STAT(tun_tx_bytes, len - 4);
1579 }
1580
1581
1582 // Process CCP messages
1583 void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1584 {
1585         uint8_t b[MAXETHER];
1586         uint8_t *q;
1587
1588         CSTAT(processccp);
1589
1590         LOG_HEX(5, "CCP", p, l);
1591
1592         if (session[s].ppp.phase < Network)
1593         {
1594                 LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1595                 return;
1596         }
1597
1598         if (l < 1)
1599         {
1600                 LOG(1, s, t, "Short CCP packet\n");
1601                 STAT(tunnel_rx_errors);
1602         }
1603
1604         LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
1605         if (*p == ConfigAck)
1606         {
1607                 switch (session[s].ppp.ccp)
1608                 {
1609                 case RequestSent:
1610                         initialise_restart_count(s, ccp);
1611                         change_state(s, ccp, AckReceived);
1612                         break;
1613
1614                 case AckReceived:
1615                 case Opened:
1616                         LOG(2, s, t, "CCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
1617                         sendccp(s, t);
1618                         change_state(s, ccp, RequestSent);
1619                         break;
1620
1621                 case AckSent:
1622                         LOG(3, s, t, "CCP: Opened\n");
1623                         change_state(s, ccp, Opened);
1624                         break;
1625
1626                 default:
1627                         LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1628                 }
1629         }
1630         else if (*p == ConfigReq)
1631         {
1632                 if (l < 6) // accept no compression
1633                         *p = ConfigAck;
1634                 else // compression requested--reject
1635                         *p = ConfigRej;
1636
1637                 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1638                 if (!q) return;
1639
1640                 switch (session[s].ppp.ccp)
1641                 {
1642                 case Closed:
1643                         q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
1644                         if (!q) return;
1645                         *q = TerminateAck;
1646                         *((uint16_t *) (q + 2)) = htons(l = 4);
1647                         break;
1648
1649                 case Stopped:
1650                         initialise_restart_count(s, ccp);
1651                         sendccp(s, t);
1652                         if (*q == ConfigAck)
1653                                 change_state(s, ccp, AckSent);
1654                         else
1655                                 change_state(s, ccp, RequestSent);
1656
1657                         break;
1658
1659                 case RequestSent:
1660                         if (*q == ConfigAck)
1661                                 change_state(s, ccp, AckSent);
1662
1663                         break;
1664
1665                 case AckReceived:
1666                         if (*q == ConfigAck)
1667                                 change_state(s, ccp, Opened);
1668
1669                         break;
1670
1671                 case Opened:
1672                         initialise_restart_count(s, ccp);
1673                         sendccp(s, t);
1674                         /* fallthrough */
1675
1676                 case AckSent:
1677                         if (*q == ConfigAck)
1678                                 change_state(s, ccp, AckSent);
1679                         else
1680                                 change_state(s, ccp, RequestSent);
1681
1682                         break;
1683
1684                 default:
1685                         LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1686                         return;
1687                 }
1688
1689                 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1690                 tunnelsend(b, l + (q - b), t);
1691         }
1692         else if (*p == TerminateReq)
1693         {
1694                 *p = TerminateAck;
1695                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPCCP);
1696                 if (!q) return;
1697                 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1698                 tunnelsend(b, l + (q - b), t);
1699                 change_state(s, ccp, Stopped);
1700         }
1701         else if (*p != CodeRej)
1702         {
1703                 ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
1704         }
1705 }
1706
1707 // send a CHAP challenge
1708 void sendchap(sessionidt s, tunnelidt t)
1709 {
1710         uint8_t b[MAXETHER];
1711         uint16_t r;
1712         uint8_t *q;
1713
1714         CSTAT(sendchap);
1715
1716         r = radiusnew(s);
1717         if (!r)
1718         {
1719                 LOG(1, s, t, "No RADIUS to send challenge\n");
1720                 STAT(tunnel_tx_errors);
1721                 return;
1722         }
1723
1724         LOG(1, s, t, "Send CHAP challenge\n");
1725
1726         radius[r].chap = 1;             // CHAP not PAP
1727         radius[r].id++;
1728         if (radius[r].state != RADIUSCHAP)
1729                 radius[r].try = 0;
1730
1731         radius[r].state = RADIUSCHAP;
1732         radius[r].retry = backoff(radius[r].try++);
1733         if (radius[r].try > 5)
1734         {
1735                 sessionshutdown(s, "CHAP timeout.", 3, 0);
1736                 STAT(tunnel_tx_errors);
1737                 return ;
1738         }
1739         q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
1740         if (!q) return;
1741
1742         *q = 1;                                 // challenge
1743         q[1] = radius[r].id;                    // ID
1744         q[4] = 16;                              // value size (size of challenge)
1745         memcpy(q + 5, radius[r].auth, 16);      // challenge
1746         strcpy((char *) q + 21, hostname);      // our name
1747         *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1748         tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1749 }
1750
1751 // fill in a L2TP message with a PPP frame,
1752 // copies existing PPP message and changes magic number if seen
1753 // returns start of PPP frame
1754 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
1755 {
1756         if (size < 12) // Need more space than this!!
1757         {
1758                 static int backtrace_count = 0;
1759                 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1760                 log_backtrace(backtrace_count, 5)
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                 static int backtrace_count = 0;
1784                 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1785                 log_backtrace(backtrace_count, 5)
1786                 return NULL;
1787         }
1788
1789         if (p && l)
1790                 memcpy(b, p, l);
1791
1792         return b;
1793 }
1794
1795 static int add_lcp_auth(uint8_t *b, int size, int authtype)
1796 {
1797         int len = 0;
1798         if ((authtype == AUTHCHAP && size < 5) || size < 4)
1799                 return 0;
1800
1801         *b++ = 3; // Authentication-Protocol
1802         if (authtype == AUTHCHAP)
1803         {
1804                 len = *b++ = 5; // length
1805                 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1806                 *b++ = 5; // MD5
1807         }
1808         else if (authtype == AUTHPAP)
1809         {
1810                 len = *b++ = 4; // length
1811                 *(uint16_t *) b = htons(PPPPAP); b += 2;
1812         }
1813         else
1814         {
1815                 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1816         }
1817
1818         return len;
1819 }
1820
1821 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1822 void sendlcp(sessionidt s, tunnelidt t)
1823 {
1824         uint8_t b[500], *q, *l;
1825         int authtype = sess_local[s].lcp_authtype;
1826
1827         if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
1828                 return;
1829
1830         LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
1831             authtype ? " (" : "",
1832             authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
1833             authtype ? ")" : "");
1834
1835         l = q;
1836         *l++ = ConfigReq;
1837         *l++ = ++sess_local[s].lcp_ident; // ID
1838
1839         l += 2; //Save space for length
1840
1841         if (sess_local[s].ppp_mru)
1842         {
1843                 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1844                 *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
1845         }
1846
1847         if (authtype)
1848                 l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1849
1850         *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1851         *(uint32_t *) l = htonl(session[s].magic);
1852         l += 4;
1853
1854         *(uint16_t *)(q + 2) = htons(l - q); // Length
1855
1856         LOG_HEX(5, "PPPLCP", q, l - q);
1857         if (config->debug > 3) dumplcp(q, l - q);
1858
1859         tunnelsend(b, (l - b), t);
1860         restart_timer(s, lcp);
1861 }
1862
1863 // Send CCP request for no compression
1864 void sendccp(sessionidt s, tunnelidt t)
1865 {
1866         uint8_t b[500], *q;
1867
1868         if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
1869                 return;
1870
1871         LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
1872
1873         *q = ConfigReq;
1874         *(q + 1) = ++sess_local[s].lcp_ident; // ID
1875         *(uint16_t *)(q + 2) = htons(4); // Length
1876
1877         LOG_HEX(5, "PPPCCP", q, 4);
1878         tunnelsend(b, (q - b) + 4 , t);
1879         restart_timer(s, ccp);
1880 }
1881
1882 // Reject unknown/unconfigured protocols
1883 void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
1884 {
1885
1886         uint8_t buf[MAXETHER];
1887         uint8_t *q;
1888         int mru = session[s].mru;
1889         if (mru < MINMTU) mru = MINMTU;
1890         if (mru > sizeof(buf)) mru = sizeof(buf);
1891
1892         l += 6;
1893         if (l > mru) l = mru;
1894
1895         q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
1896         if (!q) return;
1897
1898         *q = ProtocolRej;
1899         *(q + 1) = ++sess_local[s].lcp_ident;
1900         *(uint16_t *)(q + 2) = htons(l);
1901         *(uint16_t *)(q + 4) = htons(proto);
1902         memcpy(q + 6, p, l - 6);
1903
1904         if (proto == PPPIPV6CP)
1905                 LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
1906         else
1907                 LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
1908
1909         tunnelsend(buf, l + (q - buf), t);
1910 }