ppp.c

   1 // L2TPNS PPP Stuff
   2
   3 char const *cvs_id_ppp = "$Id: ppp.c,v 1.6 2004-06-28 02:43:13 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 tapfd;
  21 extern char hostname[];
  22 extern u32 eth_tx;
  23 extern time_t time_now;
  24 extern struct configt *config;
  25
  26 // Process PAP messages
  27 void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l)
  28 {
  29         char user[129];
  30         char pass[129];
  31
  32
  33         CSTAT(call_processpap);
  34
  35         log_hex(5, "PAP", p, l);
  36         if (l < 4)
  37         {
  38                 log(1, 0, s, t, "Short PAP %u bytes\n", l);
  39                 STAT(tunnel_rx_errors);
  40                 return ;
  41         }
  42         if (*p != 1)
  43         {
  44                 log(1, 0, s, t, "Unexpected PAP code %d\n", *p);
  45                 STAT(tunnel_rx_errors);
  46                 return ;
  47         }
  48         if (ntohs(*(u16 *) (p + 2)) > l)
  49         {
  50                 log(1, 0, s, t, "Length mismatch PAP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
  51                 STAT(tunnel_rx_errors);
  52                 return ;
  53         }
  54         {
  55                 u8 *b = p;
  56                 b += 4;
  57                 if (*b && *b < sizeof(user))
  58                         memcpy(user, b + 1, *b);
  59                 user[*b] = 0;
  60                 b += 1 + *b;
  61                 if (*b && *b < sizeof(pass))
  62                         memcpy(pass, b + 1, *b);
  63                 pass[*b] = 0;
  64                 log(3, 0, s, t, "PAP login %s/%s\n", user, pass);
  65         }
  66         if (session[s].ip || !session[s].radius)
  67         {
  68                 // respond now, either no RADIUS available or already authenticated
  69                 u8 b[MAXCONTROL];
  70                 u8 id = p[1];
  71                 u8 *p = makeppp(b, sizeof(b), 0, 0, t, s, PPPPAP);
  72                 if (!p) {       // Failed to make ppp header!
  73                         log(1,0,0,0, "Failed to make PPP header in process pap!\n");
  74                         return;
  75                 }
  76                 if (session[s].ip)
  77                         *p = 2;              // ACK
  78                 else
  79                         *p = 3;              // cant authorise
  80                 p[1] = id;
  81                 *(u16 *) (p + 2) = htons(5); // length
  82                 p[4] = 0;               // no message
  83                 if (session[s].ip)
  84                 {
  85                     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);
  86                 }
  87                 else
  88                 {
  89                     log(1, 0, s, t, "No radius session available to authenticate session...\n");
  90                 }
  91                 log(3, 0, s, t, "Fallback response to PAP (%s)\n", (session[s].ip) ? "ACK" : "NAK");
  92                 tunnelsend(b, 5 + (p - b), t); // send it
  93         }
  94         else
  95         {                          // set up RADIUS request
  96                 u16 r = session[s].radius;
  97
  98                 // Run PRE_AUTH plugins
  99                 struct param_pre_auth packet = { &tunnel[t], &session[s], strdup(user), strdup(pass), PPPPAP, 1 };
 100                 run_plugins(PLUGIN_PRE_AUTH, &packet);
 101                 if (!packet.continue_auth)
 102                 {
 103                         log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
 104                         if (packet.username) free(packet.username);
 105                         if (packet.password) free(packet.password);
 106                         return;
 107                 }
 108
 109                 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
 110                 strncpy(radius[r].pass, packet.password, sizeof(radius[r].pass) - 1);
 111
 112                 free(packet.username);
 113                 free(packet.password);
 114
 115                 radius[r].id = p[1];
 116                 log(3, 0, s, t, "Sending login for %s/%s to radius\n", user, pass);
 117                 radiussend(r, RADIUSAUTH);
 118         }
 119 }
 120
 121 // Process CHAP messages
 122 void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l)
 123 {
 124         u16 r;
 125         u16 len;
 126
 127
 128         CSTAT(call_processchap);
 129
 130         log_hex(5, "CHAP", p, l);
 131         r = session[s].radius;
 132         if (!r)
 133         {
 134                 log(1, 0, s, t, "Unexpected CHAP message\n");
 135
 136 // FIXME: Need to drop the session here.
 137
 138                 STAT(tunnel_rx_errors);
 139                 return;
 140         }
 141         if (*p != 2)
 142         {
 143                 log(1, 0, s, t, "Unexpected CHAP response code %d\n", *p);
 144                 STAT(tunnel_rx_errors);
 145                 return;
 146         }
 147         if (p[1] != radius[r].id)
 148         {
 149                 log(1, 0, s, t, "Wrong CHAP response ID %d (should be %d) (%d)\n", p[1], radius[r].id, r);
 150                 STAT(tunnel_rx_errors);
 151                 return ;
 152         }
 153         len = ntohs(*(u16 *) (p + 2));
 154         if (len > l)
 155         {
 156                 log(1, 0, s, t, "Bad CHAP length %d\n", len);
 157                 STAT(tunnel_rx_errors);
 158                 return ;
 159         }
 160         if (p[4] != 16)
 161         {
 162                 log(1, 0, s, t, "Bad CHAP response length %d\n", p[4]);
 163                 STAT(tunnel_rx_errors);
 164                 return ;
 165         }
 166         if (len - 21 >= sizeof(session[s].user))
 167         {
 168                 log(1, 0, s, t, "CHAP user too long %d\n", len - 21);
 169                 STAT(tunnel_rx_errors);
 170                 return ;
 171         }
 172
 173         // Run PRE_AUTH plugins
 174         {
 175                 struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 };
 176
 177                 packet.username = calloc(len-20, 1);
 178                 packet.password = calloc(16, 1);
 179                 memcpy(packet.username, p + 21, len - 21);
 180                 memcpy(packet.password, p + 5, 16);
 181
 182                 run_plugins(PLUGIN_PRE_AUTH, &packet);
 183                 if (!packet.continue_auth)
 184                 {
 185                         log(3, 0, s, t, "A plugin rejected PRE_AUTH\n");
 186                         if (packet.username) free(packet.username);
 187                         if (packet.password) free(packet.password);
 188                         return;
 189                 }
 190
 191                 strncpy(session[s].user, packet.username, sizeof(session[s].user) - 1);
 192                 memcpy(radius[r].pass, packet.password, 16);
 193
 194                 free(packet.username);
 195                 free(packet.password);
 196         }
 197
 198         radius[r].chap = 1;
 199         log(3, 0, s, t, "CHAP login %s\n", session[s].user);
 200         radiussend(r, RADIUSAUTH);
 201 }
 202
 203 char *ppp_lcp_types[] = {
 204         NULL,
 205         "ConfigReq",
 206         "ConfigAck",
 207         "ConfigNak",
 208         "ConfigRej",
 209         "TerminateReq",
 210         "TerminateAck",
 211         "CodeRej",
 212         "ProtocolRej",
 213         "EchoReq",
 214         "EchoReply",
 215         "DiscardRequest",
 216 };
 217
 218 void dumplcp(u8 *p, int l)
 219 {
 220         signed int x = l - 4;
 221         u8 *o = (p + 4);
 222
 223         log_hex(5, "PPP LCP Packet", p, l);
 224         log(4, 0, 0, 0, "PPP LCP Packet type %d (%s len %d)\n", *p, ppp_lcp_types[(int)*p], ntohs( ((u16 *) p)[1]) );
 225         log(4, 0, 0, 0, "Length: %d\n", l);
 226         if (*p != ConfigReq && *p != ConfigRej && *p != ConfigAck)
 227                 return;
 228
 229         while (x > 2)
 230         {
 231                 int type = o[0];
 232                 int length = o[1];
 233                 if (length == 0)
 234                 {
 235                         log(4, 0, 0, 0, "       Option length is 0...\n");
 236                         break;
 237                 }
 238                 if (type == 0)
 239                 {
 240                         log(4, 0, 0, 0, "       Option type is 0...\n");
 241                         x -= length;
 242                         o += length;
 243                         continue;
 244                 }
 245                 switch (type)
 246                 {
 247                         case 1: // Maximum-Receive-Unit
 248                                 log(4, 0, 0, 0, "    %s %d\n", lcp_types[type], ntohs(*(u16 *)(o + 2)));
 249                                 break;
 250                         case 3: // Authentication-Protocol
 251                                 {
 252                                         int proto = ntohs(*(u16 *)(o + 2));
 253                                         log(4, 0, 0, 0, "    %s %s\n", lcp_types[type],
 254                                                         proto == 0xC223 ? "CHAP" : "PAP");
 255                                         break;
 256                                 }
 257                         case 4: // Quality-Protocol
 258                                 {
 259                                         u32 qp = ntohl(*(u32 *)(o + 2));
 260                                         log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], qp);
 261                                         break;
 262                                 }
 263                         case 5: // Magic-Number
 264                                 {
 265                                         u32 magicno = ntohl(*(u32 *)(o + 2));
 266                                         log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], magicno);
 267                                         break;
 268                                 }
 269                         case 7: // Protocol-Field-Compression
 270                                 {
 271                                         u32 pfc = ntohl(*(u32 *)(o + 2));
 272                                         log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], pfc);
 273                                         break;
 274                                 }
 275                         case 8: // Address-And-Control-Field-Compression
 276                                 {
 277                                         u32 afc = ntohl(*(u32 *)(o + 2));
 278                                         log(4, 0, 0, 0, "    %s %x\n", lcp_types[type], afc);
 279                                         break;
 280                                 }
 281                         default:
 282                                 log(2, 0, 0, 0, "    Unknown PPP LCP Option type %d\n", type);
 283                                 break;
 284                 }
 285                 x -= length;
 286                 o += length;
 287         }
 288 }
 289
 290 // Process LCP messages
 291 void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 292 {
 293         u8 b[MAXCONTROL];
 294         u8 *q = NULL;
 295
 296
 297         CSTAT(call_processlcp);
 298
 299         log_hex(5, "LCP", p, l);
 300         if (l < 4)
 301         {
 302                 log(1, session[s].ip, s, t, "Short LCP %d bytes\n", l);
 303                 STAT(tunnel_rx_errors);
 304                 return ;
 305         }
 306         if (*p == ConfigAck)
 307         {
 308                 log(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n");
 309         }
 310         else if (*p == ConfigReq)
 311         {
 312                 signed int x = l - 4;
 313                 u8 *o = (p + 4);
 314
 315                 log(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l);
 316                 dumplcp(p, l);
 317
 318                 while (x > 2)
 319                 {
 320                         int type = o[0];
 321                         int length = o[1];
 322                         if (length == 0 || type == 0) break;
 323                         switch (type)
 324                         {
 325                                 case 1: // Maximum-Receive-Unit
 326                                         session[s].mru = ntohs(*(u16 *)(o + 2));
 327                                         break;
 328                                 case 3: // Authentication-Protocol
 329                                         {
 330                                                 int proto = ntohs(*(u16 *)(o + 2));
 331                                                 if (proto == 0xC223)
 332                                                 {
 333                                                         log(2, session[s].ip, s, t, "    Remote end is trying to do CHAP. Rejecting it.\n");
 334
 335                                                         if (!q)
 336                                                         {
 337                                                                 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 338                                                                 if (!q) {
 339                                                                         log(2, session[s].ip, s, t, " Failed to send packet.\n");
 340                                                                         break;
 341                                                                 }
 342                                                                 *q++ = ConfigNak;
 343                                                         }
 344                                                         memcpy(q, o, length);
 345                                                         *(u16 *)(q += 2) = htons(0xC023); // NAK -> Use PAP instead
 346                                                         q += length;
 347                                                 }
 348                                                 break;
 349                                         }
 350                                 case 5: // Magic-Number
 351                                         {
 352 //                                              u32 magicno = ntohl(*(u32 *)(o + 2));
 353                                                 break;
 354                                         }
 355                                 case 4: // Quality-Protocol
 356                                         {
 357 //                                              u32 qp = ntohl(*(u32 *)(o + 2));
 358                                                 break;
 359                                         }
 360                                 case 7: // Protocol-Field-Compression
 361                                         {
 362 //                                              u32 pfc = ntohl(*(u32 *)(o + 2));
 363                                                 break;
 364                                         }
 365                                 case 8: // Address-And-Control-Field-Compression
 366                                         {
 367 //                                              u32 afc = ntohl(*(u32 *)(o + 2));
 368                                                 break;
 369                                         }
 370                                 default:
 371                                         log(2, session[s].ip, s, t, "    Unknown PPP LCP Option type %d\n", type);
 372                                         break;
 373                         }
 374                         x -= length;
 375                         o += length;
 376                 }
 377
 378                 if (!q)
 379                 {
 380                         // Send back a ConfigAck
 381                         log(3, session[s].ip, s, t, "ConfigReq accepted, sending as Ack\n");
 382                         q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 383                         if (!q) {
 384                                 log(3, session[s].ip, s, t, " failed to create packet.\n");
 385                                 return;
 386                         }
 387                         *q = ConfigAck;
 388                         tunnelsend(b, l + (q - b), t);
 389                 }
 390                 else
 391                 {
 392                         // Already built a ConfigNak... send it
 393                         log(3, session[s].ip, s, t, "Sending ConfigNak\n");
 394                         tunnelsend(b, l + (q - b), t);
 395
 396                         log(3, session[s].ip, s, t, "Sending ConfigReq, requesting PAP login\n");
 397                         q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
 398                         *q++ = ConfigReq;
 399                         *(u8 *)(q++) = 3;
 400                         *(u8 *)(q++) = 4;
 401                         *(u16 *)(q += 2) = htons(0xC023);
 402                         tunnelsend(b, l + (q - b), t);
 403                 }
 404         }
 405         else if (*p == ConfigNak)
 406         {
 407                 log(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n");
 408                 dumplcp(p, l);
 409                 return ;
 410         }
 411         else if (*p == TerminateReq)
 412         {
 413                 *p = TerminateAck;     // close
 414                 q = makeppp(b, sizeof(b),  p, l, t, s, PPPLCP);
 415                 if (!q) {
 416                         log(3, session[s].ip, s, t, "Failed to create PPP packet in processlcp.\n");
 417                         return;
 418                 }
 419                 log(3, session[s].ip, s, t, "LCP: Received TerminateReq. Sending TerminateAck\n");
 420                 sessionshutdown(s, "Remote end closed connection.");
 421                 tunnelsend(b, l + (q - b), t); // send it
 422         }
 423         else if (*p == TerminateReq)
 424         {
 425                 sessionshutdown(s, "Remote end closed connection.");
 426         }
 427         else if (*p == EchoReq)
 428         {
 429                 *p = EchoReply;      // reply
 430                 *(u32 *) (p + 4) = htonl(session[s].magic); // our magic number
 431                 q = makeppp(b, sizeof(b), p, l, t, s, PPPLCP);
 432                 if (!q) {
 433                         log(3, session[s].ip, s, t, " failed to send EchoReply.\n");
 434                         return;
 435                 }
 436                 log(5, session[s].ip, s, t, "LCP: Received EchoReq. Sending EchoReply\n");
 437                 tunnelsend(b, l + (q - b), t); // send it
 438         }
 439         else if (*p == EchoReply)
 440         {
 441                 // Ignore it, last_packet time is set earlier than this.
 442         }
 443         else
 444         {
 445                 log(1, session[s].ip, s, t, "Unexpected LCP code %d\n", *p);
 446                 STAT(tunnel_rx_errors);
 447                 return ;
 448         }
 449 }
 450
 451 // Process IPCP messages
 452 void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 453 {
 454
 455         CSTAT(call_processipcp);
 456
 457         log_hex(5, "IPCP", p, l);
 458         if (l < 5)
 459         {
 460                 log(1, 0, s, t, "Short IPCP %d bytes\n", l);
 461                 STAT(tunnel_rx_errors);
 462                 return ;
 463         }
 464         if (*p == ConfigAck)
 465         {                          // happy with our IPCP
 466                 u16 r = session[s].radius;
 467                 if ((!r || radius[r].state == RADIUSIPCP) && !session[s].walled_garden) {
 468                         if (!r)
 469                                 r = radiusnew(s);
 470                         if (r)
 471                                 radiussend(r, RADIUSSTART); // send radius start, having got IPCP at last
 472                 }
 473                 session[s].flags |= SF_IPCP_ACKED;
 474
 475                 return ;                 // done
 476         }
 477         if (*p != ConfigReq)
 478         {
 479                 log(1, 0, s, t, "Unexpected IPCP code %d\n", *p);
 480                 STAT(tunnel_rx_errors);
 481                 return ;
 482         }
 483         if (ntohs(*(u16 *) (p + 2)) > l)
 484         {
 485                 log(1, 0, s, t, "Length mismatch IPCP %d/%d\n", ntohs(*(u16 *) (p + 2)), l);
 486                 STAT(tunnel_rx_errors);
 487                 return ;
 488         }
 489         if (!session[s].ip)
 490         {
 491                 log(3, 0, s, t, "Waiting on radius reply\n");
 492                 return ;                   // have to wait on RADIUS reply
 493         }
 494         // form a config reply quoting the IP in the session
 495         {
 496                 u8 b[MAXCONTROL];
 497                 u8 *i,
 498                 *q;
 499
 500                 q = p + 4;
 501                 i = p + l;
 502                 while (q < i && q[1])
 503                 {
 504                         if (*q != 0x81 && *q != 0x83 && *q != 3)
 505                                 break;
 506                         q += q[1];
 507                 }
 508                 if (q < i)
 509                 {                       // reject
 510                         u16 n = 4;
 511                         i = p + l;
 512                         q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP);
 513                         if (!q) {
 514                                 log(2, 0, s, t, "Failed to send IPCP.\n");
 515                                 return;
 516                         }
 517                         *q = ConfigRej;
 518                         p += 4;
 519                         while (p < i && p[1])
 520                         {
 521                                 if (*p != 0x81 && *p != 0x83 && *p != 3)
 522                                 {
 523                                         log(2, 0, s, t, "IPCP reject %d\n", *p);
 524                                         memcpy(q + n, p, p[1]);
 525                                         n += p[1];
 526                                 }
 527                                 p += p[1];
 528                         }
 529                         *(u16 *) (q + 2) = htons(n);
 530                         tunnelsend(b, n + (q - b), t); // send it
 531                 }
 532                 else
 533                 {
 534                         *p = ConfigAck;
 535                         i = findppp(p, 0x81); // Primary DNS address
 536                         if (i)
 537                         {
 538                                 if (*(u32 *) (i + 2) != htonl(session[s].dns1))
 539                                 {
 540                                         *(u32 *) (i + 2) = htonl(session[s].dns1);
 541                                         *p = ConfigNak;
 542                                 }
 543                         }
 544                         i = findppp(p, 0x83); // Secondary DNS address (TBA, is it)
 545                         if (i)
 546                         {
 547                                 if (*(u32 *) (i + 2) != htonl(session[s].dns2))
 548                                 {
 549                                         *(u32 *) (i + 2) = htonl(session[s].dns2);
 550                                         *p = ConfigNak;
 551                                 }
 552                         }
 553                         i = findppp(p, 3);   // IP address
 554                         if (!i || i[1] != 6)
 555                         {
 556                                 log(1, 0, s, t, "No IP in IPCP request\n");
 557                                 STAT(tunnel_rx_errors);
 558                                 return ;
 559                         }
 560                         if (*(u32 *) (i + 2) != htonl(session[s].ip))
 561                         {
 562                                 *(u32 *) (i + 2) = htonl(session[s].ip);
 563                                 *p = ConfigNak;
 564                         }
 565                         q = makeppp(b, sizeof(b), p, l, t, s, PPPIPCP);
 566                         if (!q) {
 567                                 log(2, 0, s, t, " Failed to send IPCP packet.\n");
 568                                 return;
 569                         }
 570                         tunnelsend(b, l + (q - b), t); // send it
 571                 }
 572         }
 573 }
 574
 575 // process IP packet received
 576 //
 577 // This MUST be called with at least 4 byte behind 'p'.
 578 // (i.e. this routine writes to p[-4]).
 579 void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l)
 580 {
 581         ipt ip;
 582
 583
 584         CSTAT(call_processipin);
 585
 586         log_hex(5, "IP", p, l);
 587
 588         ip = ntohl(*(u32 *)(p + 12));
 589
 590         if (l > MAXETHER)
 591         {
 592                 log(1, ip, s, t, "IP packet too long %d\n", l);
 593                 STAT(tunnel_rx_errors);
 594                 return ;
 595         }
 596
 597         // no spoof (do sessionbyip to handled statically routed subnets)
 598         if (ip != session[s].ip && sessionbyip(htonl(ip)) != s)
 599         {
 600                 log(5, ip, s, t, "Dropping packet with spoofed IP %s\n", inet_toa(htonl(ip)));
 601                 return;
 602         }
 603
 604         // Add on the tun header
 605         p -= 4;
 606         *(u32 *)p = htonl(0x00000800);
 607         l += 4;
 608
 609         if (session[s].tbf_in && !config->cluster_iam_master) { // Are we throttled and a slave?
 610                 master_throttle_packet(session[s].tbf_in, p, l); // Pass it to the master for handling.
 611                 return;
 612         }
 613
 614         session[s].cin += l - 4;
 615         session[s].total_cin += l - 4;
 616         sess_count[s].cin += l - 4;
 617
 618         session[s].pin++;
 619         eth_tx += l - 4;
 620
 621         if (session[s].snoop_ip && session[s].snoop_port)
 622         {
 623                 // Snooping this session, send it to ASIO
 624                 snoop_send_packet(p, l, session[s].snoop_ip, session[s].snoop_port);
 625         }
 626         STAT(tap_tx_packets);
 627         INC_STAT(tap_tx_bytes, l);
 628
 629         if (session[s].tbf_in && config->cluster_iam_master) { // Are we throttled and a master?? actually handle the throttled packets.
 630                 tbf_queue_packet(session[s].tbf_in, p, l);
 631                 return;
 632         }
 633
 634         // send to ethernet
 635         if (tun_write(p, l) < 0)
 636         {
 637                 STAT(tap_tx_errors);
 638                 log(0, 0, s, t, "Error writing %d bytes to TAP device: %s (tapfd=%d, p=%p)\n",
 639                         l, strerror(errno), tapfd, p);
 640         }
 641
 642 }
 643
 644 //
 645 // Helper routine for the TBF filters.
 646 // Used to send queued data in from the user.
 647 //
 648 void send_ipin(sessionidt s, u8 *buf, int len)
 649 {
 650         log_hex(5, "IP in throttled", buf, len);
 651         if (write(tapfd, buf, len) < 0)
 652         {
 653                 STAT(tap_tx_errors);
 654                 log(0, 0, 0, 0, "Error writing %d bytes to TAP device: %s (tapfd=%d, p=%p)\n",
 655                         len, strerror(errno), tapfd, buf);
 656         }
 657
 658         // Increment packet counters
 659         session[s].cin += len - 4;
 660         session[s].total_cin += len - 4;
 661         sess_count[s].cin += len - 4;
 662
 663         session[s].pin++;
 664         eth_tx += len - 4;
 665 }
 666
 667
 668 // Process LCP messages
 669 void processccp(tunnelidt t, sessionidt s, u8 * p, u16 l)
 670 {
 671
 672         CSTAT(call_processccp);
 673
 674         log_hex(5, "CCP", p, l);
 675         if (l < 2 || (*p != ConfigReq && *p != TerminateReq))
 676         {
 677                 log(1, 0, s, t, "Unexpecetd CCP request code %d\n", *p);
 678                 STAT(tunnel_rx_errors);
 679                 return ;
 680         }
 681         // reject
 682         {
 683                 u8 b[MAXCONTROL];
 684                 u8 *q;
 685                 if (*p == ConfigReq)
 686                 {
 687                         if (l < 6)
 688                         {
 689                                 *p = ConfigAck;         // accept no compression
 690                         }
 691                         else
 692                         {
 693                                 *p = ConfigRej;        // reject
 694                         }
 695                 }
 696                 else
 697                         *p = TerminateAck;     // close
 698                 q = makeppp(b, sizeof(b), p, l, t, s, PPPCCP);
 699                 if (!q) {
 700                         log(1,0,0,0, "Failed to send CCP packet.\n");
 701                         return;
 702                 }
 703                 tunnelsend(b, l + (q - b), t); // send it
 704         }
 705 }
 706
 707 // send a CHAP PP packet
 708 void sendchap(tunnelidt t, sessionidt s)
 709 {
 710         u8 b[MAXCONTROL];
 711         u16 r = session[s].radius;
 712         u8 *q;
 713
 714         CSTAT(call_sendchap);
 715
 716         if (!r)
 717         {
 718                 log(1, 0, s, t, "No RADIUS to send challenge\n");
 719                 STAT(tunnel_tx_errors);
 720                 return ;
 721         }
 722         log(1, 0, s, t, "Send CHAP challenge\n");
 723         {                            // new challenge
 724                 int n;
 725                 for (n = 0; n < 15; n++)
 726                         radius[r].auth[n] = rand();
 727         }
 728         radius[r].chap = 1;          // CHAP not PAP
 729         radius[r].id++;
 730         if (radius[r].state != RADIUSCHAP)
 731                 radius[r].try = 0;
 732         radius[r].state = RADIUSCHAP;
 733         radius[r].retry = backoff(radius[r].try++);
 734         if (radius[r].try > 5)
 735         {
 736                 sessionshutdown(s, "Timeout CHAP");
 737                 STAT(tunnel_tx_errors);
 738                 return ;
 739         }
 740         q = makeppp(b, sizeof(b), 0, 0, t, s, PPPCHAP);
 741         if (!q) {
 742                 log(1, 0, s, t, "failed to send CHAP challenge.\n");
 743                 return;
 744         }
 745         *q = 1;                      // challenhe
 746         q[1] = radius[r].id;         // ID
 747         q[4] = 16;                   // length
 748         memcpy(q + 5, radius[r].auth, 16); // challenge
 749         strcpy(q + 21, hostname);    // our name
 750         *(u16 *) (q + 2) = htons(strlen(hostname) + 21); // length
 751         tunnelsend(b, strlen(hostname) + 21 + (q - b), t); // send it
 752 }
 753
 754 // fill in a L2TP message with a PPP frame,
 755 // copies existing PPP message and changes magic number if seen
 756 // returns start of PPP frame
 757 u8 *makeppp(u8 * b, int size, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtype)
 758 {
 759
 760         if (size < 12)
 761                 return NULL;    // Need more space than this!!
 762
 763         *(u16 *) (b + 0) = htons(0x0002); // L2TP with no options
 764         *(u16 *) (b + 2) = htons(tunnel[t].far); // tunnel
 765         *(u16 *) (b + 4) = htons(session[s].far); // session
 766         b += 6;
 767         if (mtype != PPPLCP && !(session[s].l2tp_flags & SESSIONACFC))
 768         {
 769                 *(u16 *) b = htons(0xFF03); // HDLC header
 770                 b += 2;
 771         }
 772         if (mtype < 0x100 && session[s].l2tp_flags & SESSIONPFC)
 773                 *b++ = mtype;
 774         else
 775         {
 776                 *(u16 *) b = htons(mtype);
 777                 b += 2;
 778         }
 779
 780         if (l + 12 > size) {
 781                 log(3,0,0,0, "Would have overflowed the buffer in makeppp: size %d, len %d.\n", size, l);
 782                 return NULL;    // Run out of room to hold the packet!
 783         }
 784         if (p && l)
 785                 memcpy(b, p, l);
 786         return b;
 787 }
 788
 789 // find a PPP option, returns point to option, or 0 if not found
 790 u8 *findppp(u8 * b, u8 mtype)
 791 {
 792         u16 l = ntohs(*(u16 *) (b + 2));
 793         if (l < 4)
 794                 return 0;
 795         b += 4;
 796         l -= 4;
 797         while (l)
 798         {
 799                 if (l < b[1] || !b[1])
 800                         return 0;            // faulty
 801                 if (*b == mtype)
 802                         return b;
 803                 l -= b[1];
 804                 b += b[1];
 805         }
 806         return 0;
 807 }
 808
 809 // Send initial LCP ConfigReq
 810 void initlcp(tunnelidt t, sessionidt s)
 811 {
 812         char b[500] = {0}, *q;
 813
 814         q = makeppp(b, sizeof(b), NULL, 0, t, s, PPPLCP);
 815         if (!q) {
 816                 log(1, 0, s, t, "Failed to send LCP ConfigReq.\n");
 817                 return;
 818         }
 819         log(4, 0, s, t, "Sending LCP ConfigReq for PAP\n");
 820         *q = ConfigReq;
 821         *(u8 *)(q + 1) = (time_now % 255) + 1; // ID
 822         *(u16 *)(q + 2) = htons(8); // Length
 823         *(u8 *)(q + 4) = 3;
 824         *(u8 *)(q + 5) = 4;
 825         *(u16 *)(q + 6) = htons(0xC023); // PAP
 826         tunnelsend(b, 12 + 8, t);
 827 }
 828