ppp.c

   1 // L2TPNS PPP Stuff
   2
   3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.11 2004/08/02 06:06:28 fred_nerk Exp $";
   4
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <stdlib.h>
  10 #include "l2tpns.h"
  11 #include "constants.h"
  12 #include "plugin.h"
  13 #include "util.h"
  14 #include "tbf.h"
  15 #include "cluster.h"
  16
  17 extern tunnelt *tunnel;
  18 extern sessiont *session;
  19 extern radiust *radius;
  20 extern int tunfd;
  21 extern char hostname[];
  22 extern u32 eth_tx;
  23 extern time_t time_now;
  24 extern struct configt *config;
  25
  26 void sendccp(tunnelidt t, sessionidt s);
  27
  28 // Process PAP messages
  29 void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
  30 {
  31         char user[129];
  32         char pass[129];
  33
  34
  35         CSTAT(call_processpap);
  36
  37         log_hex(5, "PAP", p, l);
  38         if (l < 4)
  39         {
  40                 log(1, 0, s, t, "Short PAP %u bytes\n", l);
  41                 STAT(tunnel_rx_errors);
  42                 return ;
  43         }
  44         if (*p != 1)
  45         {
  46                 log(1, 0, s, t, "Unexpected PAP code %d\n", *p);
  47                 STAT(tunnel_rx_errors);
  48                 return ;
  49         }
  50         if (ntohs(*(u16 *) (p + 2)) > l)
  51         {
  52                 log(1, 0, s, t, "Length mismatch PAP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
  53                 STAT(tunnel_rx_errors);
  54                 return ;
  55         }
  56         {
  57                 u8 *b = p;
  58                 b += 4;
  59                 if (*b && *b < sizeof(user))
  60                         memcpy(user, b + 1, *b);
  61                 user[*b] = 0;
  62                 b += 1 + *b;
  63                 if (*b && *b < sizeof(pass))
  64                         memcpy(pass, b + 1, *b);
  65                 pass[*b] = 0;
  66                 log(3, 0, s, t, "PAP login %s/%s\n", user, pass);
  67         }
  68         if (session[s].ip || !session[s].radius)
  69         {
  70                 // respond now, either no RADIUS available or already authenticated
  71                 u8 b[MAXCONTROL];
  72                 u8 id = p[1];
  73                 u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
  74                 if (!p) {       // Failed to make ppp header!
  75                         log(1,0,0,0, "Failed to make PPP header in process pap!\n");
  76                         return;
  77                 }
  78                 if (session[s].ip)
  79                         *p = 2;              // ACK
  80                 else
  81                         *p = 3;              // cant authorise
  82                 p[1] = id;
  83                 *(u16 *) (p + 2) = htons(5); // length
  84                 p[4] = 0;               // no message
  85                 if (session[s].ip)
  86                 {
  87                     log(3, session[s].ip, s, t, "%d Already an IP allocated: %s (%d)\n", getpid(), inet_toa(htonl(session[s].ip)), session[s].ip_pool_index);
  88                         session[s].flags &= ~SF_IPCP_ACKED;
  89                 }
  90                 else
  91                 {
  92                     log(1, 0, s, t, "No radius session available to authenticate session...\n");
  93                 }
  94                 log(3, 0, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
  95                 tunnelsend(b, 5 + (p - b), t); // send it
  96         }
  97         else
  98         {                          // set up RADIUS request
  99                 u16 r = session[s].radius;
 100
 101                 // Run PRE_AUTH plugins
 102                 struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
 103                 run_plugins(PLUGIN_PRE_AUTH, &packet);
 104                 if (!packet.continue_auth)
 105                 {
 106                         log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
 107                         if (packet.username) free(packet.username);
 108                         if (packet.password) free(packet.password);
 109                         return;
 110                 }
 111
 112                 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
 113                 strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
 114
 115                 free(packet.username);
 116                 free(packet.password);
 117
 118                 radius[r].id = p[1];
 119                 log(3, 0, s, t, "Sending login for %s/%s to radius\n", user, pass);
 120                 radiussend(r, RADIUSAUTH);
 121         }
 122 }
 123
 124 // Process CHAP messages
 125 void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
 126 {
 127         u16 r;
 128         u16 len;
 129
 130
 131         CSTAT(call_processchap);
 132
 133         log_hex(5, "CHAP", p, l);
 134         r = session[s].radius;
 135         if (!r)
 136         {
 137                 log(1, 0, s, t, "Unexpected CHAP message\n");
 138
 139 // FIXME: Need to drop the session here.
 140
 141                 STAT(tunnel_rx_errors);
 142                 return;
 143         }
 144         if (*p != 2)
 145         {
 146                 log(1, 0, s, t, "Unexpected CHAP response code %d\n", *p);
 147                 STAT(tunnel_rx_errors);
 148                 return;
 149         }
 150         if (p[1] != radius[r].id)
 151         {
 152                 log(1, 0, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
 153                 STAT(tunnel_rx_errors);
 154                 return ;
 155         }
 156         len = ntohs(*(u16 *) (p + 2));
 157         if (len > l)
 158         {
 159                 log(1, 0, s, t, "Bad CHAP length %d\n", len);
 160                 STAT(tunnel_rx_errors);
 161                 return ;
 162         }
 163         if (p[4] != 16)
 164         {
 165                 log(1, 0, s, t, "Bad CHAP response length %d\n", p[4]);
 166                 STAT(tunnel_rx_errors);
 167                 return ;
 168         }
 169         if (len - 21 >= sizeof(session[s].user))
 170         {
 171                 log(1, 0, s, t, "CHAP user too long %d\n", len - 21);
 172                 STAT(tunnel_rx_errors);
 173                 return ;
 174         }
 175
 176         // Run PRE_AUTH plugins
 177         {
 178                 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
 179
 180                 packet.username = calloc(len-20, 1);
 181                 packet.password = calloc(16, 1);
 182                 memcpy(packet.username, p + 21, len - 21);
 183                 memcpy(packet.password, p + 5, 16);
 184
 185                 run_plugins(PLUGIN_PRE_AUTH, &packet);
 186                 if (!packet.continue_auth)
 187                 {
 188                         log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
 189                         if (packet.username) free(packet.username);
 190                         if (packet.password) free(packet.password);
 191                         return;
 192                 }
 193
 194                 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
 195                 memcpy(radius[r].pass, packet.password, 16);
 196
 197                 free(packet.username);
 198                 free(packet.password);
 199         }
 200
 201         radius[r].chap = 1;
 202         log(3, 0, s, t, "CHAP login %s\n", session[s].user);
 203         radiussend(r, RADIUSAUTH);
 204 }
 205
 206 char *ppp_lcp_types[] = {
 207         NULL,
 208         "ConfigReq",
 209         "ConfigAck",
 210         "ConfigNak",
 211         "ConfigRej",
 212         "TerminateReq",
 213         "TerminateAck",
 214         "CodeRej",
 215         "ProtocolRej",
 216         "EchoReq",
 217         "EchoReply",
 218         "DiscardRequest",
 219         "IdentRequest",
 220 };
 221
 222 void dumplcp(u8 *p, int l)
 223 {
 224         signed int x = l - 4;
 225         u8 *o = (p + 4);
 226
 227         log_hex(5, "PPP LCP Packet", p, l);
 228         log(4, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
 229         log(4, 0, 0, 0, "Length: %d\n", l);
 230         if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
 231                 return;
 232
 233         while (x > 2)
 234         {
 235                 int type = o[0];
 236                 int length = o[1];
 237                 if (length < 2)
 238                 {
 239                         log(4, 0, 0, 0, "       Option length is %d...\n", length);
 240                         break;
 241                 }
 242                 if (type == 0)
 243                 {
 244                         log(4, 0, 0, 0, "       Option type is 0...\n");
 245                         x -= length;
 246                         o += length;
 247                         continue;
 248                 }
 249                 switch (type)
 250                 {
 251                         case 1: // Maximum-Receive-Unit
 252                                 if (length == 4)
 253                                 log(4, 0, 0, 0, "    %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
 254                                 else
 255                                         log(4, 0, 0, 0, "    %s odd length %d\n", lcp_types[type], length);
 256                                 break;
 257                         case 3: // Authentication-Protocol
 258                                 {
 259                                         if (length == 4)
 260                                         {
 261                                         int proto = ntohs(*(u16 *)(o + 2));
 262                                                 log(4, 0, 0, 0, "   %s 0x%x (%s)\n", lcp_types[type], proto,
 263                                                         proto == 0xC223 ? "CHAP" :
 264                                                         proto == 0xC023 ? "PAP"  : "UNKNOWN");
 265                                         }
 266                                         else
 267                                                 log(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
 268                                         break;
 269                                 }
 270                         case 4: // Quality-Protocol
 271                                 {
 272                                         u32 qp = ntohl(*(u32 *)(o + 2));
 273                                         log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], qp);
 274                                         break;
 275                                 }
 276                         case 5: // Magic-Number
 277                                 {
 278                                         if (length == 6)
 279                                         {
 280                                         u32 magicno = ntohl(*(u32 *)(o + 2));
 281                                         log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], magicno);
 282                                         }
 283                                         else
 284                                                 log(4, 0, 0, 0, "   %s odd length %d\n", lcp_types[type], length);
 285                                         break;
 286                                 }
 287                         case 7: // Protocol-Field-Compression
 288                                 {
 289                                         log(4, 0, 0, 0, "    %s\n", lcp_types[type]);
 290                                         break;
 291                                 }
 292                         case 8: // Address-And-Control-Field-Compression
 293                                 {
 294                                         log(4, 0, 0, 0, "    %s\n", lcp_types[type]);
 295                                         break;
 296                                 }
 297                         default:
 298                                 log(2, 0, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
 299                                 break;
 300                 }
 301                 x -= length;
 302                 o += length;
 303         }
 304 }
 305
 306 // Process LCP messages
 307 void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 308 {
 309         u8 b[MAXCONTROL];
 310         u8 *q = NULL;
 311         u32  magicno = 0;
 312
 313
 314         CSTAT(call_processlcp);
 315
 316         log_hex(5, "LCP", p, l);
 317         if (l < 4)
 318         {
 319                 log(1, session[s].ip, s, t, "Short LCP %d bytes\n", l);
 320                 STAT(tunnel_rx_errors);
 321                 return ;
 322         }
 323         if (*p == ConfigAck)
 324         {
 325                 log(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n");
 326                 session[s].flags |= SESSIONLCPACK;
 327         }
 328         else if (*p == ConfigReq)
 329         {
 330                 signed int x = l - 4;
 331                 u8 *o = (p + 4);
 332
 333                 log(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
 334                 dumplcp(p, l);
 335
 336                 while (x > 2)
 337                 {
 338                         int type = o[0];
 339                         int length = o[1];
 340                         if (length == 0 || type == 0) break;
 341                         switch (type)
 342                         {
 343                                 case 1: // Maximum-Receive-Unit
 344                                         session[s].mru = ntohs(*(u16 *)(o + 2));
 345                                         break;
 346                                 case 2: // asyncmap
 347                                         log_hex(2, "PPP LCP Packet", p, l);
 348                                         log(2, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
 349                                         break;
 350                                 case 3: // Authentication-Protocol
 351                                         {
 352                                                 int proto = ntohs(*(u16 *)(o + 2));
 353                                                 if (proto == 0xC223)
 354                                                 {
 355                                                         log(2, session[s].ip, s, t, "    Remote end is trying to do CHAP. Rejecting it.\n");
 356
 357                                                         if (!q)
 358                                                         {
 359                                                                 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 360                                                                 if (!q) {
 361                                                                         log(2, session[s].ip, s, t, " Failed to send packet.\n");
 362                                                                         break;
 363                                                                 }
 364                                                                 *q++ = ConfigNak;
 365                                                         }
 366                                                         memcpy(q, o, length);
 367                                                         *(u16 *)(q += 2) = htons(0xC023); // NAK -> Use PAP instead
 368                                                         q += length;
 369                                                 }
 370                                                 break;
 371                                         }
 372                                 case 5: // Magic-Number
 373                                         {
 374                                                 magicno = ntohl(*(u32 *)(o + 2));
 375                                                 break;
 376                                         }
 377                                 case 4: // Quality-Protocol
 378                                 case 7: // Protocol-Field-Compression
 379                                 case 8: // Address-And-Control-Field-Compression
 380                                                 break;
 381                                 case 13: // CallBack option for LCP extention of win2000/routers L2TP client
 382                                 case 17:
 383                                 case 18:
 384                                 {
 385                                         // Reject LCP CallBack
 386                                         log(2, session[s].ip, s, t, "    PPP LCP Option type %d, len=%d\n", type, length);
 387                                         memcpy(p + 4, o, length);
 388                                         *(u16 *)(p + 2) = htons(length + 4);
 389                                         *p = ConfigRej;
 390                                         q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP);
 391                                         tunnelsend(b, 12 + length + 4, t);
 392                                         return;
 393                                         }
 394
 395                                 default:
 396                                         // Reject Unknown LCP Option to stop to send it again
 397                                         log(2, session[s].ip, s, t, "    Unknown PPP LCP Option type %d\n", type);
 398                                         memcpy(p + 4, o, length);
 399                                         *(u16 *)(p + 2) = htons(length + 4);
 400                                         *p = ConfigRej;
 401                                         q = makeppp(b,sizeof(b), p, length + 4, t, s, PPPLCP);
 402                                         tunnelsend(b, 12 + length + 4, t);
 403                                         return;
 404                         }
 405                         x -= length;
 406                         o += length;
 407                 }
 408
 409                 if (!q)
 410                 {
 411                         // Send back a ConfigAck
 412                         log(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n");
 413                         q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 414                         if (!q) {
 415                                 log(3, session[s].ip, s, t, " failed to create packet.\n");
 416                                 return;
 417                         }
 418                         *q = ConfigAck;
 419                         tunnelsend(b, l + (q - b), t);
 420                         // For win2k L2TP clients, LCP should be initiated by the LNS
 421                         if (magicno) initlcp(t, s);
 422                 }
 423                 else
 424                 {
 425                         // Already built a ConfigNak... send it
 426                         log(3, session[s].ip, s, t, "Sending ConfigNak\n");
 427                         tunnelsend(b, l + (q - b), t);
 428                 }
 429
 430                 if (!(session[s].flags & SESSIONLCPACK))
 431                         initlcp(t, s);
 432         }
 433         else if (*p == ConfigNak)
 434         {
 435                 log(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
 436                 dumplcp(p, l);
 437                 return ;
 438         }
 439         else if (*p == TerminateReq)
 440         {
 441                 *p = TerminateAck;     // close
 442                 q = makeppp(b, sizeof(b),  p, l, t, s, PPPLCP);
 443                 if (!q) {
 444                         log(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n");
 445                         return;
 446                 }
 447                 log(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
 448                 sessionshutdown(s, "Remote end closed connection.");
 449                 tunnelsend(b, l + (q - b), t); // send it
 450         }
 451         else if (*p == TerminateAck)
 452         {
 453                 sessionshutdown(s, "Connection closed.");
 454         }
 455         else if (*p == EchoReq)
 456         {
 457                 *p = EchoReply;      // reply
 458                 *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
 459                 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 460                 if (!q) {
 461                         log(3, session[s].ip, s, t, " failed to send EchoReply.\n");
 462                         return;
 463                 }
 464                 log(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
 465                 tunnelsend(b, l + (q - b), t); // send it
 466         }
 467         else if (*p == EchoReply)
 468         {
 469                 // Ignore it, last_packet time is set earlier than this.
 470         }
 471         else if (*p == IdentRequest)
 472         {
 473                 *p = CodeRej;
 474                 if (l > MAXCONTROL)
 475                 {
 476                         log(1, 0, s, t, "Truncated Ident Packet (length=%d) to 1400 bytes\n", l);
 477                         l = 1400;
 478                 }
 479                 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 480                 if (!q)
 481                 {
 482                         log(3, session[s].ip, s, t, "Failed to create IdentRej.\n");
 483                         return;
 484                 }
 485                 log_hex(5, "LCPIdentRej", q, l + 4);
 486                 tunnelsend(b, 12 + 4 + l, t);
 487         }
 488         else
 489         {
 490                 log(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p);
 491                 STAT(tunnel_rx_errors);
 492                 return ;
 493         }
 494 }
 495
 496 // Process IPCP messages
 497 void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 498 {
 499
 500         CSTAT(call_processipcp);
 501
 502         log_hex(5, "IPCP", p, l);
 503         if (l < 5)
 504         {
 505                 log(1, 0, s, t, "Short IPCP %d bytes\n", l);
 506                 STAT(tunnel_rx_errors);
 507                 return ;
 508         }
 509         if (*p == ConfigAck)
 510         {
 511                 // happy with our IPCP
 512                 u16 r = session[s].radius;
 513                 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden) {
 514                         if (!r)
 515                                 r = radiusnew(s);
 516                         if (r)
 517                                 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
 518                 }
 519                 session[s].flags |= SF_IPCP_ACKED;
 520
 521                 log(3, session[s].ip, s, t, "IPCP Acked, session is now active\n");
 522                 return;
 523         }
 524         if (*p != ConfigReq)
 525         {
 526                 log(1, 0, s, t, "Unexpected IPCP code %d\n", *p);
 527                 STAT(tunnel_rx_errors);
 528                 return ;
 529         }
 530         log(4, session[s].ip, s, t, "IPCP ConfigReq received\n");
 531         if (ntohs(*(u16 *) (p + 2)) > l)
 532         {
 533                 log(1, 0, s, t, "Length mismatch IPCP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
 534                 STAT(tunnel_rx_errors);
 535                 return ;
 536         }
 537         if (!session[s].ip)
 538         {
 539                 log(3, 0, s, t, "Waiting on radius reply\n");
 540                 return ;                   // have to wait on RADIUS reply
 541         }
 542         // form a config reply quoting the IP in the session
 543         {
 544                 u8 b[MAXCONTROL];
 545                 u8 *i,
 546                 *q;
 547
 548                 l = ntohs(*(u16 *) (p + 2)); // We must use length from IPCP len field
 549                 q = p + 4;
 550                 i = p + l;
 551                 while (q < i && q[1])
 552                 {
 553                         if (*q != 0x81 && *q != 0x83 && *q != 3)
 554                                 break;
 555                         q += q[1];
 556                 }
 557                 if (q < i)
 558                 {
 559                         // reject
 560                         u16 n = 4;
 561                         i = p + l;
 562                         if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
 563                         {
 564                                 log(2, 0, s, t, "Failed to send IPCP ConfigRej\n");
 565                                 return;
 566                         }
 567                         *q = ConfigRej;
 568                         p += 4;
 569                         while (p < i && p[1])
 570                         {
 571                                 if (*p != 0x81 && *p != 0x83 && *p != 3)
 572                                 {
 573                                         log(2, 0, s, t, "IPCP reject %d\n", *p);
 574                                         memcpy(q + n, p, p[1]);
 575                                         n += p[1];
 576                                 }
 577                                 p += p[1];
 578                         }
 579                         *(u16 *) (q + 2) = htons(n);
 580                         log(4, session[s].ip, s, t, "Sending ConfigRej\n");
 581                         tunnelsend(b, n + (q - b), t); // send it
 582                 }
 583                 else
 584                 {
 585                         log(4, session[s].ip, s, t, "Sending ConfigAck\n");
 586                         *p = ConfigAck;
 587                         if ((i = findppp(p, 0x81))) // Primary DNS address
 588                         {
 589                                 if (*(u32 *) (i + 2) != htonl(session[s].dns1))
 590                                 {
 591                                         *(u32 *) (i + 2) = htonl(session[s].dns1);
 592                                         *p = ConfigNak;
 593                                         log(5, session[s].ip, s, t, "   DNS1 = %s\n", inet_toa(session[s].dns1));
 594                                 }
 595                         }
 596                         if ((i = findppp(p, 0x83))) // Secondary DNS address (TBA, is it)
 597                         {
 598                                 if (*(u32 *) (i + 2) != htonl(session[s].dns2))
 599                                 {
 600                                         *(u32 *) (i + 2) = htonl(session[s].dns2);
 601                                         *p = ConfigNak;
 602                                         log(5, session[s].ip, s, t, "   DNS2 = %s\n", inet_toa(session[s].dns1));
 603                                 }
 604                         }
 605                         i = findppp(p, 3);   // IP address
 606                         if (!i || i[1] != 6)
 607                         {
 608                                 log(1, 0, s, t, "No IP in IPCP request\n");
 609                                 STAT(tunnel_rx_errors);
 610                                 return ;
 611                         }
 612                         if (*(u32 *) (i + 2) != htonl(session[s].ip))
 613                         {
 614                                 *(u32 *) (i + 2) = htonl(session[s].ip);
 615                                 *p = ConfigNak;
 616                                 log(4, session[s].ip, s, t, " No, a ConfigNak, client is requesting IP - sending %s\n",
 617                                                 inet_toa(htonl(session[s].ip)));
 618                         }
 619                         if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP)))
 620                         {
 621                                 log(2, 0, s, t, " Failed to send IPCP packet.\n");
 622                                 return;
 623                         }
 624                         tunnelsend(b, l + (q - b), t); // send it
 625                 }
 626         }
 627 }
 628
 629 // process IP packet received
 630 //
 631 // This MUST be called with at least 4 byte behind 'p'.
 632 // (i.e. this routine writes to p[-4]).
 633 void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
 634 {
 635         ipt ip;
 636
 637
 638         CSTAT(call_processipin);
 639
 640         log_hex(5, "IP", p, l);
 641
 642         ip = ntohl(*(u32 *)(p + 12));
 643
 644         if (l > MAXETHER)
 645         {
 646                 log(1, ip, s, t, "IP packet too long %d\n", l);
 647                 STAT(tunnel_rx_errors);
 648                 return ;
 649         }
 650
 651         // no spoof (do sessionbyip to handled statically routed subnets)
 652         if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
 653         {
 654                 log(5, ip, s, t, "Dropping packet with spoofed IP %s\n", inet_toa(htonl(ip)));
 655                 return;
 656         }
 657
 658         // Add on the tun header
 659         p -= 4;
 660         *(u32 *)p = htonl(0x00000800);
 661         l += 4;
 662
 663         if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
 664                 master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
 665                 return;
 666         }
 667
 668         session[s].cin += l - 4;
 669         session[s].total_cin += l - 4;
 670         sess_count[s].cin += l - 4;
 671
 672         session[s].pin++;
 673         eth_tx += l - 4;
 674
 675         if (session[s].snoop_ip && session[s].snoop_port)
 676         {
 677                 // Snooping this session, send it to ASIO
 678                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
 679         }
 680         STAT(tun_tx_packets);
 681         INC_STAT(tun_tx_bytes, l);
 682
 683         if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
 684                 tbf_queue_packet(session[s].tbf_in, p, l);
 685                 return;
 686         }
 687
 688         // send to ethernet
 689         if (tun_write(p, l) < 0)
 690         {
 691                 STAT(tun_tx_errors);
 692                 log(0, 0, s, t, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
 693                         l, strerror(errno), tunfd, p);
 694         }
 695
 696 }
 697
 698 //
 699 // Helper routine for the TBF filters.
 700 // Used to send queued data in from the user.
 701 //
 702 void send_ipin(sessionidt s, u8 *buf, int len)
 703 {
 704         log_hex(5, "IP in throttled", buf, len);
 705         if (write(tunfd, buf, len) < 0)
 706         {
 707                 STAT(tun_tx_errors);
 708                 log(0, 0, 0, 0, "Error writing %d bytes to TUN device: %s (tunfd=%d, p=%p)\n",
 709                         len, strerror(errno), tunfd, buf);
 710         }
 711
 712         // Increment packet counters
 713         session[s].cin += len - 4;
 714         session[s].total_cin += len - 4;
 715         sess_count[s].cin += len - 4;
 716
 717         session[s].pin++;
 718         eth_tx += len - 4;
 719 }
 720
 721
 722 // Process LCP messages
 723 void processccp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 724 {
 725
 726         CSTAT(call_processccp);
 727
 728         log_hex(5, "CCP", p, l);
 729         if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
 730         {
 731                 log(1, 0, s, t, "Unexpecetd CCP request code %d\n", *p);
 732                 STAT(tunnel_rx_errors);
 733                 return ;
 734         }
 735         // reject
 736         {
 737                 u8 b[MAXCONTROL];
 738                 u8 *q;
 739                 if (*p == ConfigReq)
 740                 {
 741                         if (l < 6)
 742                         {
 743                                 *p = ConfigAck;         // accept no compression
 744                         }
 745                         else
 746                         {
 747                                 *p = ConfigRej;        // reject
 748                                 sendccp(t, s);
 749                         }
 750                 }
 751                 else
 752                         *p = TerminateAck;     // close
 753                 if (!(q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP)))
 754                 {
 755                         log(1,0,0,0, "Failed to send CCP packet.\n");
 756                         return;
 757                 }
 758                 tunnelsend(b, l + (q - b), t); // send it
 759         }
 760 }
 761
 762 // send a CHAP PP packet
 763 void sendchap(tunnelidt t, sessionidt s)
 764 {
 765         u8 b[MAXCONTROL];
 766         u16 r = session[s].radius;
 767         u8 *q;
 768
 769         CSTAT(call_sendchap);
 770
 771         if (!r)
 772         {
 773                 log(1, 0, s, t, "No RADIUS to send challenge\n");
 774                 STAT(tunnel_tx_errors);
 775                 return ;
 776         }
 777         log(1, 0, s, t, "Send CHAP challenge\n");
 778         {                            // new challenge
 779                 int n;
 780                 for (n = 0; n < 15; n++)
 781                         radius[r].auth[n] = rand();
 782         }
 783         radius[r].chap = 1;          // CHAP not PAP
 784         radius[r].id++;
 785         if (radius[r].state != RADIUSCHAP)
 786                 radius[r].try = 0;
 787         radius[r].state = RADIUSCHAP;
 788         radius[r].retry = backoff(radius[r].try++);
 789         if (radius[r].try > 5)
 790         {
 791                 sessionshutdown(s, "Timeout CHAP");
 792                 STAT(tunnel_tx_errors);
 793                 return ;
 794         }
 795         q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
 796         if (!q) {
 797                 log(1, 0, s, t, "failed to send CHAP challenge.\n");
 798                 return;
 799         }
 800         *q = 1;                      // challenhe
 801         q[1] = radius[r].id;         // ID
 802         q[4] = 16;                   // length
 803         memcpy(q + 5, radius[r].auth, 16); // challenge
 804         strcpy(q + 21, hostname);    // our name
 805         *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
 806         tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
 807 }
 808
 809 // fill in a L2TP message with a PPP frame,
 810 // copies existing PPP message and changes magic number if seen
 811 // returns start of PPP frame
 812 u8 *makeppp(u8 * b, int size, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtype)
 813 {
 814
 815         if (size < 12)
 816                 return NULL;    // Need more space than this!!
 817
 818         *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
 819         *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
 820         *(u16 *) (b + 4) = htons(session[s].far); // session
 821         b += 6;
 822         if (mtype && !(session[s].l2tp_flags & SESSIONACFC))
 823         {
 824                 *(u16 *) b = htons(0xFF03); // HDLC header
 825                 b += 2;
 826         }
 827         if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
 828                 *b++ = mtype;
 829         else
 830         {
 831                 *(u16 *) b = htons(mtype);
 832                 b += 2;
 833         }
 834
 835         if (l + 12 > size) {
 836                 log(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l);
 837                 return NULL;    // Run out of room to hold the packet!
 838         }
 839         if (p && l)
 840                 memcpy(b, p, l);
 841         return b;
 842 }
 843
 844 // find a PPP option, returns point to option, or 0 if not found
 845 u8 *findppp(u8 * b, u8 mtype)
 846 {
 847         u16 l = ntohs(*(u16 *) (b + 2));
 848         if (l < 4)
 849                 return 0;
 850         b += 4;
 851         l -= 4;
 852         while (l)
 853         {
 854                 if (l < b[1] || !b[1])
 855                         return 0;            // faulty
 856                 if (*b == mtype)
 857                         return b;
 858                 l -= b[1];
 859                 b += b[1];
 860         }
 861         return 0;
 862 }
 863
 864 // Send initial LCP ConfigReq
 865 void initlcp(tunnelidt t, sessionidt s)
 866 {
 867         char b[500] = {0}, *q;
 868
 869         q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
 870         if (!q) {
 871                 log(1, 0, s, t, "Failed to send LCP ConfigReq.\n");
 872                 return;
 873         }
 874         log(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
 875         *q = ConfigReq;
 876         *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
 877         *(u16 *)(q + 2) = htons(8); // Length
 878         *(u8 *)(q + 4) = 3;
 879         *(u8 *)(q + 5) = 4;
 880         *(u16 *)(q + 6) = htons(0xC023); // PAP
 881         tunnelsend(b, 12 + 8, t);
 882 }
 883
 884 // Send CCP reply
 885 void sendccp(tunnelidt t, sessionidt s)
 886 {
 887         char *q, b[500] = {0};
 888
 889         q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPCCP);
 890         *q = ConfigReq;
 891         *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
 892         *(u16 *)(q + 2) = htons(4); // Length
 893         log_hex(5, "PPPCCP", q, 4);
 894         tunnelsend(b, (q - b) + 4 , t);
 895 }
 896