pppd/plugins/rp-pppoe/discovery.c

   1 /***********************************************************************
   2 *
   3 * discovery.c
   4 *
   5 * Perform PPPoE discovery
   6 *
   7 * Copyright (C) 1999 by Roaring Penguin Software Inc.
   8 *
   9 ***********************************************************************/
  10
  11 static char const RCSID[] =
  12 "$Id: discovery.c,v 1.3 2004/11/04 10:07:37 paulus Exp $";
  13
  14 #include "pppoe.h"
  15
  16 #ifdef HAVE_SYSLOG_H
  17 #include <syslog.h>
  18 #endif
  19
  20 #include <string.h>
  21 #include <stdlib.h>
  22 #include <errno.h>
  23
  24 #ifdef HAVE_SYS_TIME_H
  25 #include <sys/time.h>
  26 #endif
  27
  28 #ifdef HAVE_SYS_UIO_H
  29 #include <sys/uio.h>
  30 #endif
  31
  32 #ifdef HAVE_UNISTD_H
  33 #include <unistd.h>
  34 #endif
  35
  36 #ifdef USE_LINUX_PACKET
  37 #include <sys/ioctl.h>
  38 #include <fcntl.h>
  39 #endif
  40
  41 #include <signal.h>
  42
  43 /**********************************************************************
  44 *%FUNCTION: parseForHostUniq
  45 *%ARGUMENTS:
  46 * type -- tag type
  47 * len -- tag length
  48 * data -- tag data.
  49 * extra -- user-supplied pointer.  This is assumed to be a pointer to int.
  50 *%RETURNS:
  51 * Nothing
  52 *%DESCRIPTION:
  53 * If a HostUnique tag is found which matches our PID, sets *extra to 1.
  54 ***********************************************************************/
  55 void
  56 parseForHostUniq(UINT16_t type, UINT16_t len, unsigned char *data,
  57                  void *extra)
  58 {
  59     int *val = (int *) extra;
  60     if (type == TAG_HOST_UNIQ && len == sizeof(pid_t)) {
  61         pid_t tmp;
  62         memcpy(&tmp, data, len);
  63         if (tmp == getpid()) {
  64             *val = 1;
  65         }
  66     }
  67 }
  68
  69 /**********************************************************************
  70 *%FUNCTION: packetIsForMe
  71 *%ARGUMENTS:
  72 * conn -- PPPoE connection info
  73 * packet -- a received PPPoE packet
  74 *%RETURNS:
  75 * 1 if packet is for this PPPoE daemon; 0 otherwise.
  76 *%DESCRIPTION:
  77 * If we are using the Host-Unique tag, verifies that packet contains
  78 * our unique identifier.
  79 ***********************************************************************/
  80 int
  81 packetIsForMe(PPPoEConnection *conn, PPPoEPacket *packet)
  82 {
  83     int forMe = 0;
  84
  85     /* If packet is not directed to our MAC address, forget it */
  86     if (memcmp(packet->ethHdr.h_dest, conn->myEth, ETH_ALEN)) return 0;
  87
  88     /* If we're not using the Host-Unique tag, then accept the packet */
  89     if (!conn->useHostUniq) return 1;
  90
  91     parsePacket(packet, parseForHostUniq, &forMe);
  92     return forMe;
  93 }
  94
  95 /**********************************************************************
  96 *%FUNCTION: parsePADOTags
  97 *%ARGUMENTS:
  98 * type -- tag type
  99 * len -- tag length
 100 * data -- tag data
 101 * extra -- extra user data.  Should point to a PacketCriteria structure
 102 *          which gets filled in according to selected AC name and service
 103 *          name.
 104 *%RETURNS:
 105 * Nothing
 106 *%DESCRIPTION:
 107 * Picks interesting tags out of a PADO packet
 108 ***********************************************************************/
 109 void
 110 parsePADOTags(UINT16_t type, UINT16_t len, unsigned char *data,
 111               void *extra)
 112 {
 113     struct PacketCriteria *pc = (struct PacketCriteria *) extra;
 114     PPPoEConnection *conn = pc->conn;
 115     int i;
 116
 117     switch(type) {
 118     case TAG_AC_NAME:
 119         pc->seenACName = 1;
 120         if (conn->printACNames) {
 121             printf("Access-Concentrator: %.*s\n", (int) len, data);
 122         }
 123         if (conn->acName && len == strlen(conn->acName) &&
 124             !strncmp((char *) data, conn->acName, len)) {
 125             pc->acNameOK = 1;
 126         }
 127         break;
 128     case TAG_SERVICE_NAME:
 129         pc->seenServiceName = 1;
 130         if (conn->printACNames && len > 0) {
 131             printf("       Service-Name: %.*s\n", (int) len, data);
 132         }
 133         if (conn->serviceName && len == strlen(conn->serviceName) &&
 134             !strncmp((char *) data, conn->serviceName, len)) {
 135             pc->serviceNameOK = 1;
 136         }
 137         break;
 138     case TAG_AC_COOKIE:
 139         if (conn->printACNames) {
 140             printf("Got a cookie:");
 141             /* Print first 20 bytes of cookie */
 142             for (i=0; i<len && i < 20; i++) {
 143                 printf(" %02x", (unsigned) data[i]);
 144             }
 145             if (i < len) printf("...");
 146             printf("\n");
 147         }
 148         conn->cookie.type = htons(type);
 149         conn->cookie.length = htons(len);
 150         memcpy(conn->cookie.payload, data, len);
 151         break;
 152     case TAG_RELAY_SESSION_ID:
 153         if (conn->printACNames) {
 154             printf("Got a Relay-ID:");
 155             /* Print first 20 bytes of relay ID */
 156             for (i=0; i<len && i < 20; i++) {
 157                 printf(" %02x", (unsigned) data[i]);
 158             }
 159             if (i < len) printf("...");
 160             printf("\n");
 161         }
 162         conn->relayId.type = htons(type);
 163         conn->relayId.length = htons(len);
 164         memcpy(conn->relayId.payload, data, len);
 165         break;
 166     case TAG_SERVICE_NAME_ERROR:
 167         if (conn->printACNames) {
 168             printf("Got a Service-Name-Error tag: %.*s\n", (int) len, data);
 169         } else {
 170             syslog(LOG_ERR, "PADO: Service-Name-Error: %.*s", (int) len, data);
 171             exit(1);
 172         }
 173         break;
 174     case TAG_AC_SYSTEM_ERROR:
 175         if (conn->printACNames) {
 176             printf("Got a System-Error tag: %.*s\n", (int) len, data);
 177         } else {
 178             syslog(LOG_ERR, "PADO: System-Error: %.*s", (int) len, data);
 179             exit(1);
 180         }
 181         break;
 182     case TAG_GENERIC_ERROR:
 183         if (conn->printACNames) {
 184             printf("Got a Generic-Error tag: %.*s\n", (int) len, data);
 185         } else {
 186             syslog(LOG_ERR, "PADO: Generic-Error: %.*s", (int) len, data);
 187             exit(1);
 188         }
 189         break;
 190     }
 191 }
 192
 193 /**********************************************************************
 194 *%FUNCTION: parsePADSTags
 195 *%ARGUMENTS:
 196 * type -- tag type
 197 * len -- tag length
 198 * data -- tag data
 199 * extra -- extra user data (pointer to PPPoEConnection structure)
 200 *%RETURNS:
 201 * Nothing
 202 *%DESCRIPTION:
 203 * Picks interesting tags out of a PADS packet
 204 ***********************************************************************/
 205 void
 206 parsePADSTags(UINT16_t type, UINT16_t len, unsigned char *data,
 207               void *extra)
 208 {
 209     PPPoEConnection *conn = (PPPoEConnection *) extra;
 210     switch(type) {
 211     case TAG_SERVICE_NAME:
 212         syslog(LOG_DEBUG, "PADS: Service-Name: '%.*s'", (int) len, data);
 213         break;
 214     case TAG_SERVICE_NAME_ERROR:
 215         syslog(LOG_ERR, "PADS: Service-Name-Error: %.*s", (int) len, data);
 216         fprintf(stderr, "PADS: Service-Name-Error: %.*s\n", (int) len, data);
 217         exit(1);
 218     case TAG_AC_SYSTEM_ERROR:
 219         syslog(LOG_ERR, "PADS: System-Error: %.*s", (int) len, data);
 220         fprintf(stderr, "PADS: System-Error: %.*s\n", (int) len, data);
 221         exit(1);
 222     case TAG_GENERIC_ERROR:
 223         syslog(LOG_ERR, "PADS: Generic-Error: %.*s", (int) len, data);
 224         fprintf(stderr, "PADS: Generic-Error: %.*s\n", (int) len, data);
 225         exit(1);
 226     case TAG_RELAY_SESSION_ID:
 227         conn->relayId.type = htons(type);
 228         conn->relayId.length = htons(len);
 229         memcpy(conn->relayId.payload, data, len);
 230         break;
 231     }
 232 }
 233
 234 /***********************************************************************
 235 *%FUNCTION: sendPADI
 236 *%ARGUMENTS:
 237 * conn -- PPPoEConnection structure
 238 *%RETURNS:
 239 * Nothing
 240 *%DESCRIPTION:
 241 * Sends a PADI packet
 242 ***********************************************************************/
 243 void
 244 sendPADI(PPPoEConnection *conn)
 245 {
 246     PPPoEPacket packet;
 247     unsigned char *cursor = packet.payload;
 248     PPPoETag *svc = (PPPoETag *) (&packet.payload);
 249     UINT16_t namelen = 0;
 250     UINT16_t plen;
 251
 252     if (conn->serviceName) {
 253         namelen = (UINT16_t) strlen(conn->serviceName);
 254     }
 255     plen = TAG_HDR_SIZE + namelen;
 256     CHECK_ROOM(cursor, packet.payload, plen);
 257
 258     /* Set destination to Ethernet broadcast address */
 259     memset(packet.ethHdr.h_dest, 0xFF, ETH_ALEN);
 260     memcpy(packet.ethHdr.h_source, conn->myEth, ETH_ALEN);
 261
 262     packet.ethHdr.h_proto = htons(Eth_PPPOE_Discovery);
 263     packet.ver = 1;
 264     packet.type = 1;
 265     packet.code = CODE_PADI;
 266     packet.session = 0;
 267
 268     svc->type = TAG_SERVICE_NAME;
 269     svc->length = htons(namelen);
 270     CHECK_ROOM(cursor, packet.payload, namelen+TAG_HDR_SIZE);
 271
 272     if (conn->serviceName) {
 273         memcpy(svc->payload, conn->serviceName, strlen(conn->serviceName));
 274     }
 275     cursor += namelen + TAG_HDR_SIZE;
 276
 277     /* If we're using Host-Uniq, copy it over */
 278     if (conn->useHostUniq) {
 279         PPPoETag hostUniq;
 280         pid_t pid = getpid();
 281         hostUniq.type = htons(TAG_HOST_UNIQ);
 282         hostUniq.length = htons(sizeof(pid));
 283         memcpy(hostUniq.payload, &pid, sizeof(pid));
 284         CHECK_ROOM(cursor, packet.payload, sizeof(pid) + TAG_HDR_SIZE);
 285         memcpy(cursor, &hostUniq, sizeof(pid) + TAG_HDR_SIZE);
 286         cursor += sizeof(pid) + TAG_HDR_SIZE;
 287         plen += sizeof(pid) + TAG_HDR_SIZE;
 288     }
 289
 290     packet.length = htons(plen);
 291
 292     sendPacket(conn, conn->discoverySocket, &packet, (int) (plen + HDR_SIZE));
 293     if (conn->debugFile) {
 294         dumpPacket(conn->debugFile, &packet, "SENT");
 295         fprintf(conn->debugFile, "\n");
 296         fflush(conn->debugFile);
 297     }
 298 }
 299
 300 /**********************************************************************
 301 *%FUNCTION: waitForPADO
 302 *%ARGUMENTS:
 303 * conn -- PPPoEConnection structure
 304 * timeout -- how long to wait (in seconds)
 305 *%RETURNS:
 306 * Nothing
 307 *%DESCRIPTION:
 308 * Waits for a PADO packet and copies useful information
 309 ***********************************************************************/
 310 void
 311 waitForPADO(PPPoEConnection *conn, int timeout)
 312 {
 313     fd_set readable;
 314     int r;
 315     struct timeval tv;
 316     PPPoEPacket packet;
 317     int len;
 318
 319     struct PacketCriteria pc;
 320     pc.conn          = conn;
 321     pc.acNameOK      = (conn->acName)      ? 0 : 1;
 322     pc.serviceNameOK = (conn->serviceName) ? 0 : 1;
 323     pc.seenACName    = 0;
 324     pc.seenServiceName = 0;
 325
 326     do {
 327         if (BPF_BUFFER_IS_EMPTY) {
 328             tv.tv_sec = timeout;
 329             tv.tv_usec = 0;
 330
 331             FD_ZERO(&readable);
 332             FD_SET(conn->discoverySocket, &readable);
 333
 334             while(1) {
 335                 r = select(conn->discoverySocket+1, &readable, NULL, NULL, &tv);
 336                 if (r >= 0 || errno != EINTR) break;
 337             }
 338             if (r < 0) {
 339                 fatalSys("select (waitForPADO)");
 340             }
 341             if (r == 0) return;        /* Timed out */
 342         }
 343
 344         /* Get the packet */
 345         receivePacket(conn->discoverySocket, &packet, &len);
 346
 347         /* Check length */
 348         if (ntohs(packet.length) + HDR_SIZE > len) {
 349             syslog(LOG_ERR, "Bogus PPPoE length field (%u)",
 350                    (unsigned int) ntohs(packet.length));
 351             continue;
 352         }
 353
 354 #ifdef USE_BPF
 355         /* If it's not a Discovery packet, loop again */
 356         if (etherType(&packet) != Eth_PPPOE_Discovery) continue;
 357 #endif
 358
 359         if (conn->debugFile) {
 360             dumpPacket(conn->debugFile, &packet, "RCVD");
 361             fprintf(conn->debugFile, "\n");
 362             fflush(conn->debugFile);
 363         }
 364         /* If it's not for us, loop again */
 365         if (!packetIsForMe(conn, &packet)) continue;
 366
 367         if (packet.code == CODE_PADO) {
 368             if (NOT_UNICAST(packet.ethHdr.h_source)) {
 369                 printErr("Ignoring PADO packet from non-unicast MAC address");
 370                 continue;
 371             }
 372             parsePacket(&packet, parsePADOTags, &pc);
 373             if (!pc.seenACName) {
 374                 printErr("Ignoring PADO packet with no AC-Name tag");
 375                 continue;
 376             }
 377             if (!pc.seenServiceName) {
 378                 printErr("Ignoring PADO packet with no Service-Name tag");
 379                 continue;
 380             }
 381             conn->numPADOs++;
 382             if (conn->printACNames) {
 383                 printf("--------------------------------------------------\n");
 384             }
 385             if (pc.acNameOK && pc.serviceNameOK) {
 386                 memcpy(conn->peerEth, packet.ethHdr.h_source, ETH_ALEN);
 387                 if (conn->printACNames) {
 388                     printf("AC-Ethernet-Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
 389                            (unsigned) conn->peerEth[0],
 390                            (unsigned) conn->peerEth[1],
 391                            (unsigned) conn->peerEth[2],
 392                            (unsigned) conn->peerEth[3],
 393                            (unsigned) conn->peerEth[4],
 394                            (unsigned) conn->peerEth[5]);
 395                     continue;
 396                 }
 397                 conn->discoveryState = STATE_RECEIVED_PADO;
 398                 break;
 399             }
 400         }
 401     } while (conn->discoveryState != STATE_RECEIVED_PADO);
 402 }
 403
 404 /***********************************************************************
 405 *%FUNCTION: sendPADR
 406 *%ARGUMENTS:
 407 * conn -- PPPoE connection structur
 408 *%RETURNS:
 409 * Nothing
 410 *%DESCRIPTION:
 411 * Sends a PADR packet
 412 ***********************************************************************/
 413 void
 414 sendPADR(PPPoEConnection *conn)
 415 {
 416     PPPoEPacket packet;
 417     PPPoETag *svc = (PPPoETag *) packet.payload;
 418     unsigned char *cursor = packet.payload;
 419
 420     UINT16_t namelen = 0;
 421     UINT16_t plen;
 422
 423     if (conn->serviceName) {
 424         namelen = (UINT16_t) strlen(conn->serviceName);
 425     }
 426     plen = TAG_HDR_SIZE + namelen;
 427     CHECK_ROOM(cursor, packet.payload, plen);
 428
 429     memcpy(packet.ethHdr.h_dest, conn->peerEth, ETH_ALEN);
 430     memcpy(packet.ethHdr.h_source, conn->myEth, ETH_ALEN);
 431
 432     packet.ethHdr.h_proto = htons(Eth_PPPOE_Discovery);
 433     packet.ver = 1;
 434     packet.type = 1;
 435     packet.code = CODE_PADR;
 436     packet.session = 0;
 437
 438     svc->type = TAG_SERVICE_NAME;
 439     svc->length = htons(namelen);
 440     if (conn->serviceName) {
 441         memcpy(svc->payload, conn->serviceName, namelen);
 442     }
 443     cursor += namelen + TAG_HDR_SIZE;
 444
 445     /* If we're using Host-Uniq, copy it over */
 446     if (conn->useHostUniq) {
 447         PPPoETag hostUniq;
 448         pid_t pid = getpid();
 449         hostUniq.type = htons(TAG_HOST_UNIQ);
 450         hostUniq.length = htons(sizeof(pid));
 451         memcpy(hostUniq.payload, &pid, sizeof(pid));
 452         CHECK_ROOM(cursor, packet.payload, sizeof(pid)+TAG_HDR_SIZE);
 453         memcpy(cursor, &hostUniq, sizeof(pid) + TAG_HDR_SIZE);
 454         cursor += sizeof(pid) + TAG_HDR_SIZE;
 455         plen += sizeof(pid) + TAG_HDR_SIZE;
 456     }
 457
 458     /* Copy cookie and relay-ID if needed */
 459     if (conn->cookie.type) {
 460         CHECK_ROOM(cursor, packet.payload,
 461                    ntohs(conn->cookie.length) + TAG_HDR_SIZE);
 462         memcpy(cursor, &conn->cookie, ntohs(conn->cookie.length) + TAG_HDR_SIZE);
 463         cursor += ntohs(conn->cookie.length) + TAG_HDR_SIZE;
 464         plen += ntohs(conn->cookie.length) + TAG_HDR_SIZE;
 465     }
 466
 467     if (conn->relayId.type) {
 468         CHECK_ROOM(cursor, packet.payload,
 469                    ntohs(conn->relayId.length) + TAG_HDR_SIZE);
 470         memcpy(cursor, &conn->relayId, ntohs(conn->relayId.length) + TAG_HDR_SIZE);
 471         cursor += ntohs(conn->relayId.length) + TAG_HDR_SIZE;
 472         plen += ntohs(conn->relayId.length) + TAG_HDR_SIZE;
 473     }
 474
 475     packet.length = htons(plen);
 476     sendPacket(conn, conn->discoverySocket, &packet, (int) (plen + HDR_SIZE));
 477     if (conn->debugFile) {
 478         dumpPacket(conn->debugFile, &packet, "SENT");
 479         fprintf(conn->debugFile, "\n");
 480         fflush(conn->debugFile);
 481     }
 482 }
 483
 484 /**********************************************************************
 485 *%FUNCTION: waitForPADS
 486 *%ARGUMENTS:
 487 * conn -- PPPoE connection info
 488 * timeout -- how long to wait (in seconds)
 489 *%RETURNS:
 490 * Nothing
 491 *%DESCRIPTION:
 492 * Waits for a PADS packet and copies useful information
 493 ***********************************************************************/
 494 void
 495 waitForPADS(PPPoEConnection *conn, int timeout)
 496 {
 497     fd_set readable;
 498     int r;
 499     struct timeval tv;
 500     PPPoEPacket packet;
 501     int len;
 502
 503     do {
 504         if (BPF_BUFFER_IS_EMPTY) {
 505             tv.tv_sec = timeout;
 506             tv.tv_usec = 0;
 507
 508             FD_ZERO(&readable);
 509             FD_SET(conn->discoverySocket, &readable);
 510
 511             while(1) {
 512                 r = select(conn->discoverySocket+1, &readable, NULL, NULL, &tv);
 513                 if (r >= 0 || errno != EINTR) break;
 514             }
 515             if (r < 0) {
 516                 fatalSys("select (waitForPADS)");
 517             }
 518             if (r == 0) return;
 519         }
 520
 521         /* Get the packet */
 522         receivePacket(conn->discoverySocket, &packet, &len);
 523
 524         /* Check length */
 525         if (ntohs(packet.length) + HDR_SIZE > len) {
 526             syslog(LOG_ERR, "Bogus PPPoE length field (%u)",
 527                    (unsigned int) ntohs(packet.length));
 528             continue;
 529         }
 530
 531 #ifdef USE_BPF
 532         /* If it's not a Discovery packet, loop again */
 533         if (etherType(&packet) != Eth_PPPOE_Discovery) continue;
 534 #endif
 535         if (conn->debugFile) {
 536             dumpPacket(conn->debugFile, &packet, "RCVD");
 537             fprintf(conn->debugFile, "\n");
 538             fflush(conn->debugFile);
 539         }
 540
 541         /* If it's not from the AC, it's not for me */
 542         if (memcmp(packet.ethHdr.h_source, conn->peerEth, ETH_ALEN)) continue;
 543
 544         /* If it's not for us, loop again */
 545         if (!packetIsForMe(conn, &packet)) continue;
 546
 547         /* Is it PADS?  */
 548         if (packet.code == CODE_PADS) {
 549             /* Parse for goodies */
 550             parsePacket(&packet, parsePADSTags, conn);
 551             conn->discoveryState = STATE_SESSION;
 552             break;
 553         }
 554     } while (conn->discoveryState != STATE_SESSION);
 555
 556     /* Don't bother with ntohs; we'll just end up converting it back... */
 557     conn->session = packet.session;
 558
 559     syslog(LOG_INFO, "PPP session is %d", (int) ntohs(conn->session));
 560
 561     /* RFC 2516 says session id MUST NOT be zero or 0xFFFF */
 562     if (ntohs(conn->session) == 0 || ntohs(conn->session) == 0xFFFF) {
 563         syslog(LOG_ERR, "Access concentrator used a session value of %x -- the AC is violating RFC 2516", (unsigned int) ntohs(conn->session));
 564     }
 565 }
 566
 567 /**********************************************************************
 568 *%FUNCTION: discovery
 569 *%ARGUMENTS:
 570 * conn -- PPPoE connection info structure
 571 *%RETURNS:
 572 * Nothing
 573 *%DESCRIPTION:
 574 * Performs the PPPoE discovery phase
 575 ***********************************************************************/
 576 void
 577 discovery(PPPoEConnection *conn)
 578 {
 579     int padiAttempts = 0;
 580     int padrAttempts = 0;
 581     int timeout = PADI_TIMEOUT;
 582
 583     /* Skip discovery and don't open discovery socket? */
 584     if (conn->skipDiscovery && conn->noDiscoverySocket) {
 585         conn->discoveryState = STATE_SESSION;
 586         return;
 587     }
 588
 589     conn->discoverySocket =
 590         openInterface(conn->ifName, Eth_PPPOE_Discovery, conn->myEth);
 591
 592     /* Skip discovery? */
 593     if (conn->skipDiscovery) {
 594         conn->discoveryState = STATE_SESSION;
 595         return;
 596     }
 597
 598     do {
 599         padiAttempts++;
 600         if (padiAttempts > MAX_PADI_ATTEMPTS) {
 601             warn("Timeout waiting for PADO packets");
 602             close(conn->discoverySocket);
 603             conn->discoverySocket = -1;
 604             return;
 605         }
 606         sendPADI(conn);
 607         conn->discoveryState = STATE_SENT_PADI;
 608         waitForPADO(conn, timeout);
 609
 610         /* If we're just probing for access concentrators, don't do
 611            exponential backoff.  This reduces the time for an unsuccessful
 612            probe to 15 seconds. */
 613         if (!conn->printACNames) {
 614             timeout *= 2;
 615         }
 616         if (conn->printACNames && conn->numPADOs) {
 617             break;
 618         }
 619     } while (conn->discoveryState == STATE_SENT_PADI);
 620
 621     /* If we're only printing access concentrator names, we're done */
 622     if (conn->printACNames) {
 623         die(0);
 624     }
 625
 626     timeout = PADI_TIMEOUT;
 627     do {
 628         padrAttempts++;
 629         if (padrAttempts > MAX_PADI_ATTEMPTS) {
 630             warn("Timeout waiting for PADS packets");
 631             close(conn->discoverySocket);
 632             conn->discoverySocket = -1;
 633             return;
 634         }
 635         sendPADR(conn);
 636         conn->discoveryState = STATE_SENT_PADR;
 637         waitForPADS(conn, timeout);
 638         timeout *= 2;
 639     } while (conn->discoveryState == STATE_SENT_PADR);
 640
 641     /* We're done. */
 642     conn->discoveryState = STATE_SESSION;
 643     return;
 644 }
 645