ppp.c

   1 // L2TPNS PPP Stuff
   2
   3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.92 2006/01/19 21:00:24 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                                 case 5: // Magic-Number
 798                                         if (*p == ConfigNak)
 799                                         {
 800                                                 session[s].magic = ntohl(*(uint32_t *)(o + 2));
 801                                                 LOG(3, s, t, "    Remote requested magic-no %x\n", session[s].magic);
 802                                                 if (!session[s].magic) session[s].magic = time_now; // Netgear DG814 sends zero??
 803                                                 break;
 804                                         }
 805                                         // ConfigRej: fallthrough
 806
 807                                 default:
 808                                         LOG(2, s, t, "LCP: remote sent %s for type %u?\n", ppp_code(*p), type);
 809                                         sessionshutdown(s, "Unable to negotiate LCP.", 3, 0);
 810                                         break;
 811                         }
 812                         x -= length;
 813                         o += length;
 814                 }
 815
 816                 if (!authtype)
 817                 {
 818                         sessionshutdown(s, "Unsupported authentication.", 3, 0);
 819                         return;
 820                 }
 821
 822                 if (authtype > 0)
 823                         sess_local[s].lcp_authtype = authtype;
 824
 825                 switch (session[s].ppp.lcp)
 826                 {
 827                 case Closed:
 828                 case Stopped:
 829                         {
 830                                 uint8_t *response = makeppp(b, sizeof(b), p, 2, s, t, PPPLCP);
 831                                 if (!response) return;
 832                                 *response = TerminateAck;
 833                                 *((uint16_t *) (response + 2)) = htons(l = 4);
 834
 835                                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*response));
 836                                 if (config->debug > 3) dumplcp(response, l);
 837
 838                                 tunnelsend(b, l + (response - b), t);
 839                         }
 840                         break;
 841
 842                 case RequestSent:
 843                 case AckSent:
 844                         initialise_restart_count(s, lcp);
 845                         sendlcp(s, t);
 846                         break;
 847
 848                 case AckReceived:
 849                         LOG(2, s, t, "LCP: ConfigNak in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.lcp));
 850                         sendlcp(s, t);
 851                         break;
 852
 853                 case Opened:
 854                         lcp_restart(s);
 855                         sendlcp(s, t);
 856                         break;
 857
 858                 default:
 859                         LOG(2, s, t, "LCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.lcp));
 860                         return;
 861                 }
 862         }
 863         else if (*p == TerminateReq)
 864         {
 865                 *p = TerminateAck;      // close
 866                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPLCP);
 867                 if (!q) return;
 868
 869                 LOG(3, s, t, "LCP: send %s\n", ppp_code(*q));
 870                 if (config->debug > 3) dumplcp(q, l);
 871
 872                 tunnelsend(b, l + (q - b), t); // send it
 873                 sessionshutdown(s, "Remote end closed connection.", 3, 0);
 874         }
 875         else if (*p == TerminateAck)
 876         {
 877                 sessionshutdown(s, "Connection closed.", 3, 0);
 878         }
 879         else if (*p == ProtocolRej)
 880         {
 881                 uint16_t proto = 0;
 882
 883                 if (l > 4)
 884                 {
 885                         proto = *(p+4);
 886                         if (l > 5 && !(proto & 1))
 887                         {
 888                                 proto <<= 8;
 889                                 proto |= *(p+5);
 890                         }
 891                 }
 892
 893                 if (proto == PPPIPV6CP)
 894                 {
 895                         LOG(3, s, t, "IPv6 rejected\n");
 896                         change_state(s, ipv6cp, Closed);
 897                 }
 898                 else
 899                 {
 900                         LOG(3, s, t, "LCP protocol reject: 0x%04X\n", proto);
 901                 }
 902         }
 903         else if (*p == EchoReq)
 904         {
 905                 *p = EchoReply;         // reply
 906                 *(uint32_t *) (p + 4) = htonl(session[s].magic); // our magic number
 907                 q = makeppp(b, sizeof(b), p, l, s, t, PPPLCP);
 908                 if (!q) return;
 909
 910                 LOG(4, s, t, "LCP: send %s\n", ppp_code(*q));
 911                 if (config->debug > 3) dumplcp(q, l);
 912
 913                 tunnelsend(b, l + (q - b), t); // send it
 914         }
 915         else if (*p == EchoReply)
 916         {
 917                 // Ignore it, last_packet time is set earlier than this.
 918         }
 919         else if (*p != CodeRej)
 920         {
 921                 ppp_code_rej(s, t, PPPLCP, "LCP", p, l, b, sizeof(b));
 922         }
 923 }
 924
 925 static void ipcp_open(sessionidt s, tunnelidt t)
 926 {
 927         LOG(3, s, t, "IPCP: Opened, session is now active\n");
 928
 929         change_state(s, ipcp, Opened);
 930
 931         if (!(session[s].walled_garden || session[s].flags & SESSION_STARTED))
 932         {
 933                 uint16_t r = radiusnew(s);
 934                 if (r)
 935                 {
 936                         radiussend(r, RADIUSSTART); // send radius start
 937
 938                         // don't send further Start records if IPCP is restarted
 939                         session[s].flags |= SESSION_STARTED;
 940                         cluster_send_session(s);
 941                 }
 942         }
 943
 944         // start IPv6 if configured and still in passive state
 945         if (session[s].ppp.ipv6cp == Stopped)
 946         {
 947                 sendipv6cp(s, t);
 948                 change_state(s, ipv6cp, RequestSent);
 949         }
 950 }
 951
 952 // Process IPCP messages
 953 void processipcp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
 954 {
 955         uint8_t b[MAXETHER];
 956         uint8_t *q = 0;
 957         uint16_t hl;
 958
 959         CSTAT(processipcp);
 960
 961         LOG_HEX(5, "IPCP", p, l);
 962         if (l < 5)
 963         {
 964                 LOG(1, s, t, "Short IPCP %d bytes\n", l);
 965                 STAT(tunnel_rx_errors);
 966                 return ;
 967         }
 968
 969         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
 970         {
 971                 LOG(1, s, t, "Length mismatch IPCP %u/%u\n", hl, l);
 972                 STAT(tunnel_rx_errors);
 973                 return ;
 974         }
 975         l = hl;
 976
 977         if (session[s].ppp.phase < Network)
 978         {
 979                 LOG(2, s, t, "IPCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
 980                 return;
 981         }
 982
 983         LOG(3, s, t, "IPCP: recv %s\n", ppp_code(*p));
 984
 985         if (*p == ConfigAck)
 986         {
 987                 switch (session[s].ppp.ipcp)
 988                 {
 989                 case RequestSent:
 990                         initialise_restart_count(s, ipcp);
 991                         change_state(s, ipcp, AckReceived);
 992                         break;
 993
 994                 case AckReceived:
 995                 case Opened:
 996                         LOG(2, s, t, "IPCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipcp));
 997                         sendipcp(s, t);
 998                         change_state(s, ipcp, RequestSent);
 999                         break;
1000
1001                 case AckSent:
1002                         ipcp_open(s, t);
1003                         break;
1004
1005                 default:
1006                         LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1007                 }
1008         }
1009         else if (*p == ConfigReq)
1010         {
1011                 uint8_t *response = 0;
1012                 uint8_t *o = p + 4;
1013                 int length = l - 4;
1014                 int gotip = 0;
1015                 in_addr_t addr;
1016
1017                 while (length > 2)
1018                 {
1019                         switch (*o)
1020                         {
1021                         case 3: // ip address
1022                                 gotip++; // seen address
1023                                 if (o[1] != 6 || o[1] > length) return;
1024
1025                                 addr = htonl(session[s].ip);
1026                                 if (memcmp(o + 2, &addr, (sizeof addr)))
1027                                 {
1028                                         uint8_t *oq = q;
1029                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1030                                         if (!q || (q != oq && *response == ConfigRej))
1031                                         {
1032                                                 sessionshutdown(s, "Can't negotiate IPCP.", 3, 0);
1033                                                 return;
1034                                         }
1035                                 }
1036
1037                                 break;
1038
1039                         case 129: // primary DNS
1040                                 if (o[1] != 6 || o[1] > length) return;
1041
1042                                 addr = htonl(session[s].dns1);
1043                                 if (memcmp(o + 2, &addr, (sizeof addr)))
1044                                 {
1045                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1046                                         if (!q) return;
1047                                 }
1048
1049                                 break;
1050
1051                         case 131: // secondary DNS
1052                                 if (o[1] != 6 || o[1] > length) return;
1053
1054                                 addr = htonl(session[s].dns2);
1055                                 if (memcmp(o + 2, &addr, sizeof(addr)))
1056                                 {
1057                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPCP, &response, q, p, o, (uint8_t *) &addr, sizeof(addr));
1058                                         if (!q) return;
1059                                 }
1060
1061                                 break;
1062
1063                         default:
1064                                 LOG(2, s, t, "    Rejecting PPP IPCP Option type %d\n", *o);
1065                                 q = ppp_conf_rej(s, b, sizeof(b), PPPIPCP, &response, q, p, o);
1066                                 if (!q) return;
1067                         }
1068
1069                         length -= o[1];
1070                         o += o[1];
1071                 }
1072
1073                 if (response)
1074                 {
1075                         l = q - response; // IPCP packet length
1076                         *((uint16_t *) (response + 2)) = htons(l); // update header
1077                 }
1078                 else if (gotip)
1079                 {
1080                         // Send packet back as ConfigAck
1081                         response = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1082                         if (!response) return;
1083                         *response = ConfigAck;
1084                 }
1085                 else
1086                 {
1087                         LOG(1, s, t, "No IP in IPCP request\n");
1088                         STAT(tunnel_rx_errors);
1089                         return;
1090                 }
1091
1092                 switch (session[s].ppp.ipcp)
1093                 {
1094                 case Closed:
1095                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPCP);
1096                         if (!response) return;
1097                         *response = TerminateAck;
1098                         *((uint16_t *) (response + 2)) = htons(l = 4);
1099                         break;
1100
1101                 case Stopped:
1102                         initialise_restart_count(s, ipcp);
1103                         sendipcp(s, t);
1104                         if (*response == ConfigAck)
1105                                 change_state(s, ipcp, AckSent);
1106                         else
1107                                 change_state(s, ipcp, RequestSent);
1108
1109                         break;
1110
1111                 case RequestSent:
1112                         if (*response == ConfigAck)
1113                                 change_state(s, ipcp, AckSent);
1114
1115                         break;
1116
1117                 case AckReceived:
1118                         if (*response == ConfigAck)
1119                                 ipcp_open(s, t);
1120
1121                         break;
1122
1123                 case Opened:
1124                         initialise_restart_count(s, ipcp);
1125                         sendipcp(s, t);
1126                         /* fallthrough */
1127
1128                 case AckSent:
1129                         if (*response == ConfigAck)
1130                                 change_state(s, ipcp, AckSent);
1131                         else
1132                                 change_state(s, ipcp, RequestSent);
1133
1134                         break;
1135
1136                 default:
1137                         LOG(2, s, t, "IPCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipcp));
1138                         return;
1139                 }
1140
1141                 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*response));
1142                 tunnelsend(b, l + (response - b), t);
1143         }
1144         else if (*p == TerminateReq)
1145         {
1146                 *p = TerminateAck;
1147                 q = makeppp(b, sizeof(b), p, l, s, t, PPPIPCP);
1148                 if (!q) return;
1149                 LOG(3, s, t, "IPCP: send %s\n", ppp_code(*q));
1150                 tunnelsend(b, l + (q - b), t);
1151                 change_state(s, ipcp, Stopped);
1152         }
1153         else if (*p != CodeRej)
1154         {
1155                 ppp_code_rej(s, t, PPPIPCP, "IPCP", p, l, b, sizeof(b));
1156         }
1157 }
1158
1159 static void ipv6cp_open(sessionidt s, tunnelidt t)
1160 {
1161         LOG(3, s, t, "IPV6CP: Opened\n");
1162
1163         change_state(s, ipv6cp, Opened);
1164         if (session[s].ipv6prefixlen)
1165                 route6set(s, session[s].ipv6route, session[s].ipv6prefixlen, 1);
1166
1167         // Send an initial RA (TODO: Should we send these regularly?)
1168         send_ipv6_ra(s, t, NULL);
1169 }
1170
1171 // Process IPV6CP messages
1172 void processipv6cp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1173 {
1174         uint8_t b[MAXETHER];
1175         uint8_t *q = 0;
1176         uint16_t hl;
1177
1178         CSTAT(processipv6cp);
1179
1180         LOG_HEX(5, "IPV6CP", p, l);
1181         if (l < 4)
1182         {
1183                 LOG(1, s, t, "Short IPV6CP %d bytes\n", l);
1184                 STAT(tunnel_rx_errors);
1185                 return ;
1186         }
1187
1188         if ((hl = ntohs(*(uint16_t *) (p + 2))) > l)
1189         {
1190                 LOG(1, s, t, "Length mismatch IPV6CP %u/%u\n", hl, l);
1191                 STAT(tunnel_rx_errors);
1192                 return ;
1193         }
1194         l = hl;
1195
1196         if (session[s].ppp.phase < Network)
1197         {
1198                 LOG(2, s, t, "IPV6CP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1199                 return;
1200         }
1201
1202         LOG(3, s, t, "IPV6CP: recv %s\n", ppp_code(*p));
1203
1204         if (!session[s].ip)
1205         {
1206                 LOG(3, s, t, "IPV6CP: no IPv4 address (IPCP in state %s)\n", ppp_state(session[s].ppp.ipcp));
1207                 return; // need IPCP to complete...
1208         }
1209
1210         if (*p == ConfigAck)
1211         {
1212                 switch (session[s].ppp.ipv6cp)
1213                 {
1214                 case RequestSent:
1215                         initialise_restart_count(s, ipv6cp);
1216                         change_state(s, ipv6cp, AckReceived);
1217                         break;
1218
1219                 case AckReceived:
1220                 case Opened:
1221                         LOG(2, s, t, "IPV6CP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ipv6cp));
1222                         sendipv6cp(s, t);
1223                         change_state(s, ipv6cp, RequestSent);
1224                         break;
1225
1226                 case AckSent:
1227                         ipv6cp_open(s, t);
1228                         break;
1229
1230                 default:
1231                         LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1232                 }
1233         }
1234         else if (*p == ConfigReq)
1235         {
1236                 uint8_t *response = 0;
1237                 uint8_t *o = p + 4;
1238                 int length = l - 4;
1239                 int gotip = 0;
1240                 uint8_t ident[8];
1241
1242                 while (length > 2)
1243                 {
1244                         switch (*o)
1245                         {
1246                         case 1: // interface identifier
1247                                 gotip++; // seen address
1248                                 if (o[1] != 10 || o[1] > length) return;
1249
1250                                 *(uint32_t *) ident = htonl(session[s].ip);
1251                                 *(uint32_t *) (ident + 4) = 0;
1252
1253                                 if (memcmp(o + 2, ident, sizeof(ident)))
1254                                 {
1255                                         q = ppp_conf_nak(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o, ident, sizeof(ident));
1256                                         if (!q) return;
1257                                 }
1258
1259                                 break;
1260
1261                         default:
1262                                 LOG(2, s, t, "    Rejecting PPP IPV6CP Option type %d\n", *o);
1263                                 q = ppp_conf_rej(s, b, sizeof(b), PPPIPV6CP, &response, q, p, o);
1264                                 if (!q) return;
1265                         }
1266
1267                         length -= o[1];
1268                         o += o[1];
1269                 }
1270
1271                 if (response)
1272                 {
1273                         l = q - response; // IPV6CP packet length
1274                         *((uint16_t *) (response + 2)) = htons(l); // update header
1275                 }
1276                 else if (gotip)
1277                 {
1278                         // Send packet back as ConfigAck
1279                         response = makeppp(b, sizeof(b), p, l, s, t, PPPIPV6CP);
1280                         if (!response) return;
1281                         *response = ConfigAck;
1282                 }
1283                 else
1284                 {
1285                         LOG(1, s, t, "No interface identifier in IPV6CP request\n");
1286                         STAT(tunnel_rx_errors);
1287                         return;
1288                 }
1289
1290                 switch (session[s].ppp.ipv6cp)
1291                 {
1292                 case Closed:
1293                         response = makeppp(b, sizeof(b), p, 2, s, t, PPPIPV6CP);
1294                         if (!response) return;
1295                         *response = TerminateAck;
1296                         *((uint16_t *) (response + 2)) = htons(l = 4);
1297                         break;
1298
1299                 case Stopped:
1300                         initialise_restart_count(s, ipv6cp);
1301                         sendipv6cp(s, t);
1302                         if (*response == ConfigAck)
1303                                 change_state(s, ipv6cp, AckSent);
1304                         else
1305                                 change_state(s, ipv6cp, RequestSent);
1306
1307                         break;
1308
1309                 case RequestSent:
1310                         if (*response == ConfigAck)
1311                                 change_state(s, ipv6cp, AckSent);
1312
1313                         break;
1314
1315                 case AckReceived:
1316                         if (*response == ConfigAck)
1317                                 ipv6cp_open(s, t);
1318
1319                         break;
1320
1321                 case Opened:
1322                         initialise_restart_count(s, ipv6cp);
1323                         sendipv6cp(s, t);
1324                         /* fallthrough */
1325
1326                 case AckSent:
1327                         if (*response == ConfigAck)
1328                                 change_state(s, ipv6cp, AckSent);
1329                         else
1330                                 change_state(s, ipv6cp, RequestSent);
1331
1332                         break;
1333
1334                 default:
1335                         LOG(2, s, t, "IPV6CP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ipv6cp));
1336                         return;
1337                 }
1338
1339                 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*response));
1340                 tunnelsend(b, l + (response - b), t);
1341         }
1342         else if (*p == TerminateReq)
1343         {
1344                 *p = TerminateAck;
1345                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPIPV6CP);
1346                 if (!q) return;
1347                 LOG(3, s, t, "IPV6CP: send %s\n", ppp_code(*q));
1348                 tunnelsend(b, l + (q - b), t);
1349                 change_state(s, ipv6cp, Stopped);
1350         }
1351         else if (*p != CodeRej)
1352         {
1353                 ppp_code_rej(s, t, PPPIPV6CP, "IPV6CP", p, l, b, sizeof(b));
1354         }
1355 }
1356
1357 // process IP packet received
1358 //
1359 // This MUST be called with at least 4 byte behind 'p'.
1360 // (i.e. this routine writes to p[-4]).
1361 void processipin(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1362 {
1363         in_addr_t ip;
1364
1365         CSTAT(processipin);
1366
1367         LOG_HEX(5, "IP", p, l);
1368
1369         if (l < 20)
1370         {
1371                 LOG(1, s, t, "IP packet too short %d\n", l);
1372                 STAT(tunnel_rx_errors);
1373                 return ;
1374         }
1375
1376         ip = ntohl(*(uint32_t *)(p + 12));
1377
1378         if (l > MAXETHER)
1379         {
1380                 LOG(1, s, t, "IP packet too long %d\n", l);
1381                 STAT(tunnel_rx_errors);
1382                 return ;
1383         }
1384
1385         if (session[s].ppp.phase != Network || session[s].ppp.ipcp != Opened)
1386                 return;
1387
1388         // no spoof (do sessionbyip to handled statically routed subnets)
1389         if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
1390         {
1391                 LOG(5, s, t, "Dropping packet with spoofed IP %s\n", fmtaddr(htonl(ip), 0));
1392                 return;
1393         }
1394
1395         // run access-list if any
1396         if (session[s].filter_in && !ip_filter(p, l, session[s].filter_in - 1))
1397                 return;
1398
1399         // adjust MSS on SYN and SYN,ACK packets with options
1400         if ((ntohs(*(uint16_t *) (p + 6)) & 0x1fff) == 0 && p[9] == IPPROTO_TCP) // first tcp fragment
1401         {
1402                 int ihl = (p[0] & 0xf) * 4; // length of IP header
1403                 if (l >= ihl + 20 && (p[ihl + 13] & TCP_FLAG_SYN) && ((p[ihl + 12] >> 4) > 5))
1404                         adjust_tcp_mss(s, t, p, l, p + ihl);
1405         }
1406
1407         // Add on the tun header
1408         p -= 4;
1409         *(uint32_t *) p = htonl(PKTIP);
1410         l += 4;
1411
1412         // Are we throttled and a slave?
1413         if (session[s].tbf_in && !config->cluster_iam_master) {
1414                 // Pass it to the master for handling.
1415                 master_throttle_packet(session[s].tbf_in, p, l);
1416                 return;
1417         }
1418
1419         // Are we throttled and a master??
1420         if (session[s].tbf_in && config->cluster_iam_master) {
1421                 // Actually handle the throttled packets.
1422                 tbf_queue_packet(session[s].tbf_in, p, l);
1423                 return;
1424         }
1425
1426         // send to ethernet
1427         if (tun_write(p, l) < 0)
1428         {
1429                 STAT(tun_tx_errors);
1430                 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1431                         l, strerror(errno), tunfd, p);
1432
1433                 return;
1434         }
1435
1436         p += 4;
1437         l -= 4;
1438
1439         if (session[s].snoop_ip && session[s].snoop_port)
1440         {
1441                 // Snooping this session
1442                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1443         }
1444
1445         increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1446         session[s].cin_delta += l;
1447         session[s].pin++;
1448
1449         sess_local[s].cin += l;
1450         sess_local[s].pin++;
1451
1452         eth_tx += l;
1453
1454         STAT(tun_tx_packets);
1455         INC_STAT(tun_tx_bytes, l);
1456 }
1457
1458 // process IPv6 packet received
1459 //
1460 // This MUST be called with at least 4 byte behind 'p'.
1461 // (i.e. this routine writes to p[-4]).
1462 void processipv6in(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1463 {
1464         struct in6_addr ip;
1465         in_addr_t ipv4;
1466
1467         CSTAT(processipv6in);
1468
1469         LOG_HEX(5, "IPv6", p, l);
1470
1471         ip = *(struct in6_addr *) (p + 8);
1472         ipv4 = ntohl(*(uint32_t *)(p + 16));
1473
1474         if (l > MAXETHER)
1475         {
1476                 LOG(1, s, t, "IP packet too long %d\n", l);
1477                 STAT(tunnel_rx_errors);
1478                 return ;
1479         }
1480
1481         if (session[s].ppp.phase != Network || session[s].ppp.ipv6cp != Opened)
1482                 return;
1483
1484         // no spoof
1485         if (ipv4 != session[s].ip && memcmp(&config->ipv6_prefix, &ip, 8) && sessionbyipv6(ip) != s)
1486         {
1487                 char str[INET6_ADDRSTRLEN];
1488                 LOG(5, s, t, "Dropping packet with spoofed IP %s\n",
1489                                 inet_ntop(AF_INET6, &ip, str, INET6_ADDRSTRLEN));
1490                 return;
1491         }
1492
1493         // Check if it's a Router Solicition message.
1494         if (*(p + 6) == 58 && *(p + 7) == 255 && *(p + 24) == 0xFF && *(p + 25) == 2 &&
1495                         *(uint32_t *)(p + 26) == 0 && *(uint32_t *)(p + 30) == 0 &&
1496                         *(uint32_t *)(p + 34) == 0 &&
1497                         *(p + 38) == 0 && *(p + 39) == 2 && *(p + 40) == 133) {
1498                 LOG(3, s, t, "Got IPv6 RS\n");
1499                 send_ipv6_ra(s, t, &ip);
1500                 return;
1501         }
1502
1503         // Add on the tun header
1504         p -= 4;
1505         *(uint32_t *) p = htonl(PKTIPV6);
1506         l += 4;
1507
1508         // Are we throttled and a slave?
1509         if (session[s].tbf_in && !config->cluster_iam_master) {
1510                 // Pass it to the master for handling.
1511                 master_throttle_packet(session[s].tbf_in, p, l);
1512                 return;
1513         }
1514
1515         // Are we throttled and a master??
1516         if (session[s].tbf_in && config->cluster_iam_master) {
1517                 // Actually handle the throttled packets.
1518                 tbf_queue_packet(session[s].tbf_in, p, l);
1519                 return;
1520         }
1521
1522         // send to ethernet
1523         if (tun_write(p, l) < 0)
1524         {
1525                 STAT(tun_tx_errors);
1526                 LOG(0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1527                         l, strerror(errno), tunfd, p);
1528
1529                 return;
1530         }
1531
1532         p += 4;
1533         l -= 4;
1534
1535         if (session[s].snoop_ip && session[s].snoop_port)
1536         {
1537                 // Snooping this session
1538                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
1539         }
1540
1541         increment_counter(&session[s].cin, &session[s].cin_wrap, l);
1542         session[s].cin_delta += l;
1543         session[s].pin++;
1544
1545         sess_local[s].cin += l;
1546         sess_local[s].pin++;
1547
1548         eth_tx += l;
1549
1550         STAT(tun_tx_packets);
1551         INC_STAT(tun_tx_bytes, l);
1552 }
1553
1554 //
1555 // Helper routine for the TBF filters.
1556 // Used to send queued data in from the user.
1557 //
1558 void send_ipin(sessionidt s, uint8_t *buf, int len)
1559 {
1560         LOG_HEX(5, "IP in throttled", buf, len);
1561
1562         if (write(tunfd, buf, len) < 0)
1563         {
1564                 STAT(tun_tx_errors);
1565                 LOG(0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
1566                         len, strerror(errno), tunfd, buf);
1567
1568                 return;
1569         }
1570
1571         buf += 4;
1572         len -= 4;
1573
1574         if (session[s].snoop_ip && session[s].snoop_port)
1575         {
1576                 // Snooping this session
1577                 snoop_send_packet(buf, len, session[s].snoop_ip, session[s].snoop_port);
1578         }
1579
1580         // Increment packet counters
1581         increment_counter(&session[s].cin, &session[s].cin_wrap, len);
1582         session[s].cin_delta += len;
1583         session[s].pin++;
1584
1585         sess_local[s].cin += len;
1586         sess_local[s].pin++;
1587
1588         eth_tx += len;
1589
1590         STAT(tun_tx_packets);
1591         INC_STAT(tun_tx_bytes, len - 4);
1592 }
1593
1594
1595 // Process CCP messages
1596 void processccp(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l)
1597 {
1598         uint8_t b[MAXETHER];
1599         uint8_t *q;
1600
1601         CSTAT(processccp);
1602
1603         LOG_HEX(5, "CCP", p, l);
1604
1605         if (session[s].ppp.phase < Network)
1606         {
1607                 LOG(2, s, t, "CCP %s ignored in %s phase\n", ppp_code(*p), ppp_phase(session[s].ppp.phase));
1608                 return;
1609         }
1610
1611         if (l < 1)
1612         {
1613                 LOG(1, s, t, "Short CCP packet\n");
1614                 STAT(tunnel_rx_errors);
1615         }
1616
1617         LOG(3, s, t, "CCP: recv %s\n", ppp_code(*p));
1618         if (*p == ConfigAck)
1619         {
1620                 switch (session[s].ppp.ccp)
1621                 {
1622                 case RequestSent:
1623                         initialise_restart_count(s, ccp);
1624                         change_state(s, ccp, AckReceived);
1625                         break;
1626
1627                 case AckReceived:
1628                 case Opened:
1629                         LOG(2, s, t, "CCP: ConfigAck in state %s?  Sending ConfigReq\n", ppp_state(session[s].ppp.ccp));
1630                         sendccp(s, t);
1631                         change_state(s, ccp, RequestSent);
1632                         break;
1633
1634                 case AckSent:
1635                         LOG(3, s, t, "CCP: Opened\n");
1636                         change_state(s, ccp, Opened);
1637                         break;
1638
1639                 default:
1640                         LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1641                 }
1642         }
1643         else if (*p == ConfigReq)
1644         {
1645                 if (l < 6) // accept no compression
1646                         *p = ConfigAck;
1647                 else // compression requested--reject
1648                         *p = ConfigRej;
1649
1650                 q = makeppp(b, sizeof(b), p, l, s, t, PPPCCP);
1651                 if (!q) return;
1652
1653                 switch (session[s].ppp.ccp)
1654                 {
1655                 case Closed:
1656                         q = makeppp(b, sizeof(b), p, 2, s, t, PPPCCP);
1657                         if (!q) return;
1658                         *q = TerminateAck;
1659                         *((uint16_t *) (q + 2)) = htons(l = 4);
1660                         break;
1661
1662                 case Stopped:
1663                         initialise_restart_count(s, ccp);
1664                         sendccp(s, t);
1665                         if (*q == ConfigAck)
1666                                 change_state(s, ccp, AckSent);
1667                         else
1668                                 change_state(s, ccp, RequestSent);
1669
1670                         break;
1671
1672                 case RequestSent:
1673                         if (*q == ConfigAck)
1674                                 change_state(s, ccp, AckSent);
1675
1676                         break;
1677
1678                 case AckReceived:
1679                         if (*q == ConfigAck)
1680                                 change_state(s, ccp, Opened);
1681
1682                         break;
1683
1684                 case Opened:
1685                         initialise_restart_count(s, ccp);
1686                         sendccp(s, t);
1687                         /* fallthrough */
1688
1689                 case AckSent:
1690                         if (*q == ConfigAck)
1691                                 change_state(s, ccp, AckSent);
1692                         else
1693                                 change_state(s, ccp, RequestSent);
1694
1695                         break;
1696
1697                 default:
1698                         LOG(2, s, t, "CCP: ignoring %s in state %s\n", ppp_code(*p), ppp_state(session[s].ppp.ccp));
1699                         return;
1700                 }
1701
1702                 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1703                 tunnelsend(b, l + (q - b), t);
1704         }
1705         else if (*p == TerminateReq)
1706         {
1707                 *p = TerminateAck;
1708                 q = makeppp(b, sizeof(b),  p, l, s, t, PPPCCP);
1709                 if (!q) return;
1710                 LOG(3, s, t, "CCP: send %s\n", ppp_code(*q));
1711                 tunnelsend(b, l + (q - b), t);
1712                 change_state(s, ccp, Stopped);
1713         }
1714         else if (*p != CodeRej)
1715         {
1716                 ppp_code_rej(s, t, PPPCCP, "CCP", p, l, b, sizeof(b));
1717         }
1718 }
1719
1720 // send a CHAP challenge
1721 void sendchap(sessionidt s, tunnelidt t)
1722 {
1723         uint8_t b[MAXETHER];
1724         uint16_t r;
1725         uint8_t *q;
1726
1727         CSTAT(sendchap);
1728
1729         r = radiusnew(s);
1730         if (!r)
1731         {
1732                 LOG(1, s, t, "No RADIUS to send challenge\n");
1733                 STAT(tunnel_tx_errors);
1734                 return;
1735         }
1736
1737         LOG(1, s, t, "Send CHAP challenge\n");
1738
1739         radius[r].chap = 1;             // CHAP not PAP
1740         radius[r].id++;
1741         if (radius[r].state != RADIUSCHAP)
1742                 radius[r].try = 0;
1743
1744         radius[r].state = RADIUSCHAP;
1745         radius[r].retry = backoff(radius[r].try++);
1746         if (radius[r].try > 5)
1747         {
1748                 sessionshutdown(s, "CHAP timeout.", 3, 0);
1749                 STAT(tunnel_tx_errors);
1750                 return ;
1751         }
1752         q = makeppp(b, sizeof(b), 0, 0, s, t, PPPCHAP);
1753         if (!q) return;
1754
1755         *q = 1;                                 // challenge
1756         q[1] = radius[r].id;                    // ID
1757         q[4] = 16;                              // value size (size of challenge)
1758         memcpy(q + 5, radius[r].auth, 16);      // challenge
1759         strcpy((char *) q + 21, hostname);      // our name
1760         *(uint16_t *) (q + 2) = htons(strlen(hostname) + 21); // length
1761         tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
1762 }
1763
1764 // fill in a L2TP message with a PPP frame,
1765 // copies existing PPP message and changes magic number if seen
1766 // returns start of PPP frame
1767 uint8_t *makeppp(uint8_t *b, int size, uint8_t *p, int l, sessionidt s, tunnelidt t, uint16_t mtype)
1768 {
1769         if (size < 12) // Need more space than this!!
1770         {
1771                 LOG(0, s, t, "makeppp buffer too small for L2TP header (size=%d)\n", size);
1772                 return NULL;
1773         }
1774
1775         *(uint16_t *) (b + 0) = htons(0x0002); // L2TP with no options
1776         *(uint16_t *) (b + 2) = htons(tunnel[t].far); // tunnel
1777         *(uint16_t *) (b + 4) = htons(session[s].far); // session
1778         b += 6;
1779         if (mtype == PPPLCP || !(session[s].flags & SESSION_ACFC))
1780         {
1781                 *(uint16_t *) b = htons(0xFF03); // HDLC header
1782                 b += 2;
1783         }
1784         if (mtype < 0x100 && session[s].flags & SESSION_PFC)
1785                 *b++ = mtype;
1786         else
1787         {
1788                 *(uint16_t *) b = htons(mtype);
1789                 b += 2;
1790         }
1791
1792         if (l + 12 > size)
1793         {
1794                 LOG(2, s, t, "makeppp would overflow buffer (size=%d, header+payload=%d)\n", size, l + 12);
1795                 return NULL;
1796         }
1797
1798         if (p && l)
1799                 memcpy(b, p, l);
1800
1801         return b;
1802 }
1803
1804 static int add_lcp_auth(uint8_t *b, int size, int authtype)
1805 {
1806         int len = 0;
1807         if ((authtype == AUTHCHAP && size < 5) || size < 4)
1808                 return 0;
1809
1810         *b++ = 3; // Authentication-Protocol
1811         if (authtype == AUTHCHAP)
1812         {
1813                 len = *b++ = 5; // length
1814                 *(uint16_t *) b = htons(PPPCHAP); b += 2;
1815                 *b++ = 5; // MD5
1816         }
1817         else if (authtype == AUTHPAP)
1818         {
1819                 len = *b++ = 4; // length
1820                 *(uint16_t *) b = htons(PPPPAP); b += 2;
1821         }
1822         else
1823         {
1824                 LOG(0, 0, 0, "add_lcp_auth called with unsupported auth type %d\n", authtype);
1825         }
1826
1827         return len;
1828 }
1829
1830 // Send initial LCP ConfigReq for MRU, authentication type and magic no
1831 void sendlcp(sessionidt s, tunnelidt t)
1832 {
1833         uint8_t b[500], *q, *l;
1834         int authtype = sess_local[s].lcp_authtype;
1835
1836         if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPLCP)))
1837                 return;
1838
1839         LOG(3, s, t, "LCP: send ConfigReq%s%s%s\n",
1840             authtype ? " (" : "",
1841             authtype ? (authtype == AUTHCHAP ? "CHAP" : "PAP") : "",
1842             authtype ? ")" : "");
1843
1844         l = q;
1845         *l++ = ConfigReq;
1846         *l++ = ++sess_local[s].lcp_ident; // ID
1847
1848         l += 2; //Save space for length
1849
1850         if (sess_local[s].ppp_mru)
1851         {
1852                 *l++ = 1; *l++ = 4; // Maximum-Receive-Unit (length 4)
1853                 *(uint16_t *) l = htons(sess_local[s].ppp_mru); l += 2;
1854         }
1855
1856         if (authtype)
1857                 l += add_lcp_auth(l, sizeof(b) - (l - b), authtype);
1858
1859         *l++ = 5; *l++ = 6; // Magic-Number (length 6)
1860         *(uint32_t *) l = htonl(session[s].magic);
1861         l += 4;
1862
1863         *(uint16_t *)(q + 2) = htons(l - q); // Length
1864
1865         LOG_HEX(5, "PPPLCP", q, l - q);
1866         if (config->debug > 3) dumplcp(q, l - q);
1867
1868         tunnelsend(b, (l - b), t);
1869         restart_timer(s, lcp);
1870 }
1871
1872 // Send CCP request for no compression
1873 void sendccp(sessionidt s, tunnelidt t)
1874 {
1875         uint8_t b[500], *q;
1876
1877         if (!(q = makeppp(b, sizeof(b), NULL, 0, s, t, PPPCCP)))
1878                 return;
1879
1880         LOG(3, s, t, "CCP: send ConfigReq (no compression)\n");
1881
1882         *q = ConfigReq;
1883         *(q + 1) = ++sess_local[s].lcp_ident; // ID
1884         *(uint16_t *)(q + 2) = htons(4); // Length
1885
1886         LOG_HEX(5, "PPPCCP", q, 4);
1887         tunnelsend(b, (q - b) + 4 , t);
1888         restart_timer(s, ccp);
1889 }
1890
1891 // Reject unknown/unconfigured protocols
1892 void protoreject(sessionidt s, tunnelidt t, uint8_t *p, uint16_t l, uint16_t proto)
1893 {
1894
1895         uint8_t buf[MAXETHER];
1896         uint8_t *q;
1897         int mru = session[s].mru;
1898         if (mru < MINMTU) mru = MINMTU;
1899         if (mru > sizeof(buf)) mru = sizeof(buf);
1900
1901         l += 6;
1902         if (l > mru) l = mru;
1903
1904         q = makeppp(buf, sizeof(buf), 0, 0, s, t, PPPLCP);
1905         if (!q) return;
1906
1907         *q = ProtocolRej;
1908         *(q + 1) = ++sess_local[s].lcp_ident;
1909         *(uint16_t *)(q + 2) = htons(l);
1910         *(uint16_t *)(q + 4) = htons(proto);
1911         memcpy(q + 6, p, l - 6);
1912
1913         if (proto == PPPIPV6CP)
1914                 LOG(3, s, t, "LCP: send ProtocolRej (IPV6CP: not configured)\n");
1915         else
1916                 LOG(2, s, t, "LCP: sent ProtocolRej (0x%04X: unsupported)\n", proto);
1917
1918         tunnelsend(buf, l + (q - buf), t);
1919 }