mdw@git.distorted.org.uk Git - tripe/blob - server/peer.c

   1 /* -*-c-*-
   2  *
   3  * Communication with the peer
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Trivial IP Encryption (TrIPE).
  11  *
  12  * TrIPE is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * TrIPE is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with TrIPE; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 /*----- Header files ------------------------------------------------------*/
  28
  29 #include "tripe.h"
  30
  31 /*----- Static variables --------------------------------------------------*/
  32
  33 static peer *peers = 0;
  34 static sel_file sock;
  35
  36 /*----- Tunnel table ------------------------------------------------------*/
  37
  38 const tunnel_ops *tunnels[] = {
  39 #ifdef TUN_LINUX
  40   &tun_linux,
  41 #endif
  42 #ifdef TUN_BSD
  43   &tun_bsd,
  44 #endif
  45 #ifdef TUN_UNET
  46   &tun_unet,
  47 #endif
  48   &tun_slip,
  49   0
  50 }, *tun_default;
  51
  52 /*----- Main code ---------------------------------------------------------*/
  53
  54 /* --- @p_pingtype@ --- *
  55  *
  56  * Arguments:   @unsigned msg@ = message type
  57  *
  58  * Returns:     String to describe the message.
  59  */
  60
  61 static const char *p_pingtype(unsigned msg)
  62 {
  63   switch (msg & MSG_TYPEMASK) {
  64     case MISC_PING:
  65     case MISC_PONG:
  66       return "transport-ping";
  67     case MISC_EPING:
  68     case MISC_EPONG:
  69       return "encrypted-ping";
  70     default:
  71       abort();
  72   }
  73 }
  74
  75 /* --- @p_ponged@ --- *
  76  *
  77  * Arguments:   @peer *p@ = peer packet arrived from
  78  *              @unsigned msg@ = message type
  79  *              @buf *b@ = buffer containing payload
  80  *
  81  * Returns:     ---
  82  *
  83  * Use:         Processes a ping response.
  84  */
  85
  86 static void p_ponged(peer *p, unsigned msg, buf *b)
  87 {
  88   uint32 id;
  89   const octet *magic;
  90   ping *pg;
  91
  92   IF_TRACING(T_PEER, {
  93     trace(T_PEER, "peer: received %s reply from %s",
  94           p_pingtype(msg), p->spec.name);
  95     trace_block(T_PACKET, "peer: ping contents", BBASE(b), BSZ(b));
  96   })
  97
  98   if (buf_getu32(b, &id) ||
  99       (magic = buf_get(b, sizeof(pg->magic))) == 0 ||
 100       BLEFT(b)) {
 101     a_warn("PEER", "?PEER", p, "malformed-%s", p_pingtype(msg), A_END);
 102     return;
 103   }
 104
 105   for (pg = p->pings; pg; pg = pg->next) {
 106     if (pg->id == id)
 107       goto found;
 108   }
 109   a_warn("PEER",
 110          "?PEER", p,
 111          "unexpected-%s", p_pingtype(msg),
 112          "0x%08lx", (unsigned long)id,
 113          A_END);
 114   return;
 115
 116 found:
 117   if (memcmp(magic, pg->magic, sizeof(pg->magic)) != 0) {
 118     a_warn("PEER", "?PEER", p, "corrupt-%s", p_pingtype(msg), A_END);
 119     return;
 120   }
 121   p_pingdone(pg, PING_OK);
 122 }
 123
 124 /* --- @p_read@ --- *
 125  *
 126  * Arguments:   @int fd@ = file descriptor to read from
 127  *              @unsigned mode@ = what happened
 128  *              @void *v@ = an uninteresting pointer
 129  *
 130  * Returns:     ---
 131  *
 132  * Use:         Reads a packet from somewhere.
 133  */
 134
 135 static void p_read(int fd, unsigned mode, void *v)
 136 {
 137   peer *p = 0;
 138   addr a;
 139   size_t sz;
 140   ssize_t n;
 141   int ch;
 142   buf b, bb;
 143
 144   /* --- Read the data --- */
 145
 146   TIMER;
 147   sz = sizeof(addr);
 148   n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
 149   if (n < 0) {
 150     a_warn("PEER", "-", "socket-read-error", "?ERRNO", A_END);
 151     return;
 152   }
 153
 154   /* --- If the packet is a greeting, don't check peers --- */
 155
 156   if (n && buf_i[0] == (MSG_MISC | MISC_GREET)) {
 157     IF_TRACING(T_PEER, {
 158       trace(T_PEER, "peer: greeting received from INET %s %u",
 159             inet_ntoa(a.sin.sin_addr),
 160             (unsigned)ntohs(a.sin.sin_port));
 161       trace_block(T_PACKET, "peer: greeting contents", buf_i, n);
 162     })
 163     buf_init(&b, buf_i, n);
 164     buf_getbyte(&b);
 165     if (c_check(&b) || BLEFT(&b)) {
 166       a_warn("PEER", "-", "invalid-greeting", A_END);
 167       return;
 168     }
 169     a_notify("GREET",
 170              "?B64", buf_i + 1, (size_t)(n - 1),
 171              "?ADDR", &a,
 172              A_END);
 173     return;
 174   }
 175
 176   /* --- Find the appropriate peer --- */
 177
 178   assert(a.sa.sa_family == AF_INET);
 179   for (p = peers; p; p = p->next) {
 180     if (p->spec.sa.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr &&
 181         p->spec.sa.sin.sin_port == a.sin.sin_port)
 182       goto found;
 183   }
 184   a_warn("PEER", "-", "unexpected-source", "?ADDR", &a, A_END);
 185   return;
 186
 187 found:
 188   IF_TRACING(T_PEER, {
 189     trace(T_PEER, "peer: packet received from `%s'", p->spec.name);
 190     trace_block(T_PACKET, "peer: packet contents", buf_i, n);
 191   })
 192
 193   /* --- Pick the packet apart --- */
 194
 195   p->st.t_last = time(0);
 196   p->st.n_in++;
 197   p->st.sz_in += n;
 198   buf_init(&b, buf_i, n);
 199   if ((ch = buf_getbyte(&b)) < 0) {
 200     a_warn("PEER", "?PEER", p, "bad-packet", "no-type", A_END);
 201     return;
 202   }
 203   switch (ch & MSG_CATMASK) {
 204     case MSG_PACKET:
 205       if (ch & MSG_TYPEMASK) {
 206         a_warn("PEER",
 207                "?PEER", p,
 208                "bad-packet",
 209                "unknown-type", "0x%02x", ch,
 210                A_END);
 211         p->st.n_reject++;
 212         return;
 213       }
 214       buf_init(&bb, buf_o, sizeof(buf_o));
 215       if (ksl_decrypt(&p->ks, MSG_PACKET, &b, &bb)) {
 216         p->st.n_reject++;
 217         a_warn("PEER", "?PEER", p, "decrypt-failed", A_END);
 218         return;
 219       }
 220       if (BOK(&bb)) {
 221         p->st.n_ipin++;
 222         p->st.sz_ipin += BSZ(&b);
 223         p->t->ops->inject(p->t, &bb);
 224       } else {
 225         p->st.n_reject++;
 226         a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
 227       }
 228       break;
 229     case MSG_KEYEXCH:
 230       kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
 231       break;
 232     case MSG_MISC:
 233       switch (ch & MSG_TYPEMASK) {
 234         case MISC_NOP:
 235           T( trace(T_PEER, "peer: received NOP packet"); )
 236           break;
 237         case MISC_PING:
 238           buf_put(p_txstart(p, MSG_MISC | MISC_PONG), BCUR(&b), BLEFT(&b));
 239           p_txend(p);
 240           break;
 241         case MISC_PONG:
 242           p_ponged(p, MISC_PONG, &b);
 243           break;
 244         case MISC_EPING:
 245           buf_init(&bb, buf_t, sizeof(buf_t));
 246           if (ksl_decrypt(&p->ks, ch, &b, &bb)) {
 247             p->st.n_reject++;
 248             a_warn("PEER", "?PEER", p, "decrypt-failed", A_END);
 249             return;
 250           }
 251           if (BOK(&bb)) {
 252             buf_flip(&bb);
 253             if (ksl_encrypt(&p->ks, MSG_MISC | MISC_EPONG, &bb,
 254                             p_txstart(p, MSG_MISC | MISC_EPONG)))
 255               kx_start(&p->kx, 0);
 256             p_txend(p);
 257           }
 258           break;
 259         case MISC_EPONG:
 260           buf_init(&bb, buf_t, sizeof(buf_t));
 261           if (ksl_decrypt(&p->ks, ch, &b, &bb)) {
 262             p->st.n_reject++;
 263             a_warn("PEER", "?PEER", p, "decrypt-failed", A_END);
 264             return;
 265           }
 266           if (BOK(&bb)) {
 267             buf_flip(&bb);
 268             p_ponged(p, MISC_EPONG, &bb);
 269           }
 270           break;
 271       }
 272       break;
 273     default:
 274       p->st.n_reject++;
 275       a_warn("PEER",
 276              "?PEER", p,
 277              "bad-packet",
 278              "unknown-category" "0x%02x", ch,
 279              A_END);
 280       break;
 281   }
 282 }
 283
 284 /* --- @p_txstart@ --- *
 285  *
 286  * Arguments:   @peer *p@ = pointer to peer block
 287  *              @unsigned msg@ = message type code
 288  *
 289  * Returns:     A pointer to a buffer to write to.
 290  *
 291  * Use:         Starts sending to a peer.  Only one send can happen at a
 292  *              time.
 293  */
 294
 295 buf *p_txstart(peer *p, unsigned msg)
 296 {
 297   buf_init(&p->b, buf_o, sizeof(buf_o));
 298   buf_putbyte(&p->b, msg);
 299   return (&p->b);
 300 }
 301
 302 /* --- @p_txend@ --- *
 303  *
 304  * Arguments:   @peer *p@ = pointer to peer block
 305  *
 306  * Returns:     ---
 307  *
 308  * Use:         Sends a packet to the peer.
 309  */
 310
 311 static void p_setkatimer(peer *);
 312
 313 static int p_dotxend(peer *p)
 314 {
 315   if (!BOK(&p->b)) {
 316     a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
 317     return (0);
 318   }
 319   IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
 320                                  BBASE(&p->b), BLEN(&p->b)); )
 321   if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
 322              0, &p->spec.sa.sa, p->spec.sasz) < 0) {
 323     a_warn("PEER", "?PEER", p, "socket-write-error", "?ERRNO", A_END);
 324     return (0);
 325   } else {
 326     p->st.n_out++;
 327     p->st.sz_out += BLEN(&p->b);
 328     return (1);
 329   }
 330 }
 331
 332 void p_txend(peer *p)
 333 {
 334   if (p_dotxend(p) && p->spec.t_ka) {
 335     sel_rmtimer(&p->tka);
 336     p_setkatimer(p);
 337   }
 338 }
 339
 340 /* --- @p_pingwrite@ --- *
 341  *
 342  * Arguments:   @ping *p@ = ping structure
 343  *              @buf *b@ = buffer to write in
 344  *
 345  * Returns:     ---
 346  *
 347  * Use:         Fills in a ping structure and writes the packet payload.
 348  */
 349
 350 static void p_pingwrite(ping *p, buf *b)
 351 {
 352   static uint32 seq = 0;
 353
 354   p->id = U32(seq++);
 355   GR_FILL(&rand_global, p->magic, sizeof(p->magic));
 356   buf_putu32(b, p->id);
 357   buf_put(b, p->magic, sizeof(p->magic));
 358 }
 359
 360 /* --- @p_pingdone@ --- *
 361  *
 362  * Arguments:   @ping *p@ = ping structure
 363  *              @int rc@ = return code to pass on
 364  *
 365  * Returns:     ---
 366  *
 367  * Use:         Disposes of a ping structure, maybe sending a notification.
 368  */
 369
 370 void p_pingdone(ping *p, int rc)
 371 {
 372   if (p->prev) p->prev->next = p->next;
 373   else p->p->pings = p->next;
 374   if (p->next) p->next->prev = p->prev;
 375   if (rc != PING_TIMEOUT) sel_rmtimer(&p->t);
 376   T( trace(T_PEER, "peer: ping 0x%08lx done (rc = %d)",
 377            (unsigned long)p->id, rc); )
 378   if (rc >= 0) p->func(rc, p->arg);
 379 }
 380
 381 /* --- @p_pingtimeout@ --- *
 382  *
 383  * Arguments:   @struct timeval *now@ = the time now
 384  *              @void *pv@ = pointer to ping block
 385  *
 386  * Returns:     ---
 387  *
 388  * Use:         Called when a ping times out.
 389  */
 390
 391 static void p_pingtimeout(struct timeval *now, void *pv)
 392 {
 393   ping *p = pv;
 394
 395   T( trace(T_PEER, "peer: ping 0x%08lx timed out", (unsigned long)p->id); )
 396   p_pingdone(p, PING_TIMEOUT);
 397 }
 398
 399 /* --- @p_pingsend@ --- *
 400  *
 401  * Arguments:   @peer *p@ = destination peer
 402  *              @ping *pg@ = structure to fill in
 403  *              @unsigned type@ = message type
 404  *              @unsigned long timeout@ = how long to wait before giving up
 405  *              @void (*func)(int, void *)@ = callback function
 406  *              @void *arg@ = argument for callback
 407  *
 408  * Returns:     Zero if successful, nonzero if it failed.
 409  *
 410  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
 411  *              if we get an answer within the timeout, or zero if no answer.
 412  */
 413
 414 int p_pingsend(peer *p, ping *pg, unsigned type,
 415                unsigned long timeout,
 416                void (*func)(int, void *), void *arg)
 417 {
 418   buf *b, bb;
 419   struct timeval tv;
 420
 421   switch (type) {
 422     case MISC_PING:
 423       pg->msg = MISC_PONG;
 424       b = p_txstart(p, MSG_MISC | MISC_PING);
 425       p_pingwrite(pg, b);
 426       p_txend(p);
 427       break;
 428     case MISC_EPING:
 429       pg->msg = MISC_EPONG;
 430       b = p_txstart(p, MSG_MISC | MISC_EPING);
 431       buf_init(&bb, buf_t, sizeof(buf_t));
 432       p_pingwrite(pg, &bb);
 433       buf_flip(&bb);
 434       if (ksl_encrypt(&p->ks, MSG_MISC | MISC_EPING, &bb, b))
 435         kx_start(&p->kx, 0);
 436       if (!BOK(b))
 437         return (-1);
 438       p_txend(p);
 439       break;
 440     default:
 441       abort();
 442       break;
 443   }
 444
 445   pg->next = p->pings;
 446   pg->prev = 0;
 447   pg->p = p;
 448   pg->func = func;
 449   pg->arg = arg;
 450   if (p->pings) p->pings->prev = pg;
 451   p->pings = pg;
 452   gettimeofday(&tv, 0);
 453   tv.tv_sec += timeout;
 454   sel_addtimer(&sel, &pg->t, &tv, p_pingtimeout, pg);
 455   T( trace(T_PEER, "peer: send %s 0x%08lx to %s",
 456            p_pingtype(type), (unsigned long)pg->id, p->spec.name); )
 457   return (0);
 458 }
 459
 460 /* --- @p_greet@ --- *
 461  *
 462  * Arguments:   @peer *p@ = peer to send to
 463  *              @const void *c@ = pointer to challenge
 464  *              @size_t sz@ = size of challenge
 465  *
 466  * Returns:     ---
 467  *
 468  * Use:         Sends a greeting packet.
 469  */
 470
 471 void p_greet(peer *p, const void *c, size_t sz)
 472 {
 473   buf *b = p_txstart(p, MSG_MISC | MISC_GREET);
 474   buf_put(b, c, sz);
 475   p_txend(p);
 476 }
 477
 478 /* --- @p_tun@ --- *
 479  *
 480  * Arguments:   @peer *p@ = pointer to peer block
 481  *              @buf *b@ = buffer containing incoming packet
 482  *
 483  * Returns:     ---
 484  *
 485  * Use:         Handles a packet which needs to be sent to a peer.
 486  */
 487
 488 void p_tun(peer *p, buf *b)
 489 {
 490   buf *bb = p_txstart(p, MSG_PACKET);
 491
 492   TIMER;
 493   if (ksl_encrypt(&p->ks, MSG_PACKET, b, bb))
 494     kx_start(&p->kx, 0);
 495   if (BOK(bb) && BLEN(bb)) {
 496     p->st.n_ipout++;
 497     p->st.sz_ipout += BLEN(bb);
 498     p_txend(p);
 499   }
 500 }
 501
 502 /* --- @p_keyreload@ --- *
 503  *
 504  * Arguments:   ---
 505  *
 506  * Returns:     ---
 507  *
 508  * Use:         Forces a check of the daemon's keyring files.
 509  */
 510
 511 void p_keyreload(void)
 512 {
 513   peer *p;
 514
 515   if (km_reload()) {
 516     for (p = peers; p; p = p->next)
 517       kx_newkeys(&p->kx);
 518   }
 519 }
 520
 521 /* --- @p_interval@ --- *
 522  *
 523  * Arguments:   ---
 524  *
 525  * Returns:     ---
 526  *
 527  * Use:         Called periodically to do tidying.
 528  */
 529
 530 void p_interval(void)
 531 {
 532   peer *p;
 533
 534   p_keyreload();
 535   for (p = peers; p; p = p->next)
 536     ksl_prune(&p->ks);
 537 }
 538
 539 /* --- @p_stats@ --- *
 540  *
 541  * Arguments:   @peer *p@ = pointer to a peer block
 542  *
 543  * Returns:     A pointer to the peer's statistics.
 544  */
 545
 546 stats *p_stats(peer *p) { return (&p->st); }
 547
 548 /* --- @p_ifname@ --- *
 549  *
 550  * Arguments:   @peer *p@ = pointer to a peer block
 551  *
 552  * Returns:     A pointer to the peer's interface name.
 553  */
 554
 555 const char *p_ifname(peer *p) { return (p->ifname); }
 556
 557 /* --- @p_setifname@ --- *
 558  *
 559  * Arguments:   @peer *p@ = pointer to a peer block
 560  *              @const char *name@ = pointer to the new name
 561  *
 562  * Returns:     ---
 563  *
 564  * Use:         Changes the name held for a peer's interface.
 565  */
 566
 567 void p_setifname(peer *p, const char *name)
 568 {
 569   xfree(p->ifname);
 570   p->ifname = xstrdup(name);
 571   if (p->spec.tops->setifname)
 572     p->spec.tops->setifname(p->t, name);
 573 }
 574
 575 /* --- @p_addr@ --- *
 576  *
 577  * Arguments:   @peer *p@ = pointer to a peer block
 578  *
 579  * Returns:     A pointer to the peer's address.
 580  */
 581
 582 const addr *p_addr(peer *p) { return (&p->spec.sa); }
 583
 584 /* --- @p_init@ --- *
 585  *
 586  * Arguments:   @struct in_addr addr@ = address to bind to
 587  *              @unsigned port@ = port number to listen to
 588  *
 589  * Returns:     ---
 590  *
 591  * Use:         Initializes the peer system; creates the socket.
 592  */
 593
 594 void p_init(struct in_addr addr, unsigned port)
 595 {
 596   int fd;
 597   struct sockaddr_in sin;
 598   int len = PKBUFSZ;
 599
 600   /* --- Note on socket buffer sizes --- *
 601    *
 602    * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer
 603    * sizes I pass to @setsockopt@.  I'm not putting special-case code here
 604    * for Linux: BSD (at least TCPv2) does what I tell it rather than second-
 605    * guessing me.
 606    */
 607
 608   if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
 609     die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno));
 610   BURN(sin);
 611   sin.sin_family = AF_INET;
 612   sin.sin_addr = addr;
 613   sin.sin_port = htons(port);
 614   if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
 615     die(EXIT_FAILURE, "bind failed: %s", strerror(errno));
 616   if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
 617       setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) {
 618     die(EXIT_FAILURE, "failed to set socket buffer sizes: %s",
 619         strerror(errno));
 620   }
 621   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 622   sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0);
 623   sel_addfile(&sock);
 624   T( trace(T_PEER, "peer: created socket"); )
 625 }
 626
 627 /* --- @p_port@ --- *
 628  *
 629  * Arguments:   ---
 630  *
 631  * Returns:     Port number used for socket.
 632  */
 633
 634 unsigned p_port(void)
 635 {
 636   addr a;
 637   size_t sz = sizeof(addr);
 638
 639   if (getsockname(sock.fd, &a.sa, &sz))
 640     die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
 641   assert(a.sa.sa_family == AF_INET);
 642   return (ntohs(a.sin.sin_port));
 643 }
 644
 645 /* --- @p_keepalive@ --- *
 646  *
 647  * Arguments:   @struct timeval *now@ = the current time
 648  *              @void *pv@ = peer to wake up
 649  *
 650  * Returns:     ---
 651  *
 652  * Use:         Sends a keepalive ping message to its peer.
 653  */
 654
 655 static void p_keepalive(struct timeval *now, void *pv)
 656 {
 657   peer *p = pv;
 658   p_txstart(p, MSG_MISC | MISC_NOP); p_dotxend(p);
 659   T( trace(T_PEER, "peer: sent keepalive to %s", p->spec.name); )
 660   p_setkatimer(p);
 661 }
 662
 663 /* --- @p_setkatimer@ --- *
 664  *
 665  * Arguments:   @peer *p@ = peer to set
 666  *
 667  * Returns:     ---
 668  *
 669  * Use:         Resets the keepalive timer thing.
 670  */
 671
 672 static void p_setkatimer(peer *p)
 673 {
 674   struct timeval tv;
 675
 676   if (!p->spec.t_ka)
 677     return;
 678   gettimeofday(&tv, 0);
 679   tv.tv_sec += p->spec.t_ka;
 680   sel_addtimer(&sel, &p->tka, &tv, p_keepalive, p);
 681 }
 682
 683 /* --- @p_create@ --- *
 684  *
 685  * Arguments:   @peerspec *spec@ = information about this peer
 686  *
 687  * Returns:     Pointer to the peer block, or null if it failed.
 688  *
 689  * Use:         Creates a new named peer block.  No peer is actually attached
 690  *              by this point.
 691  */
 692
 693 peer *p_create(peerspec *spec)
 694 {
 695   peer *p = CREATE(peer);
 696
 697   T( trace(T_PEER, "peer: creating new peer `%s'", spec->name); )
 698   p->spec = *spec;
 699   p->spec.name = xstrdup(spec->name);
 700   p->ks = 0;
 701   p->prev = 0;
 702   p->pings = 0;
 703   p->ifname = 0;
 704   memset(&p->st, 0, sizeof(stats));
 705   p->st.t_start = time(0);
 706   if ((p->t = spec->tops->create(p, &p->ifname)) == 0)
 707     goto tidy_0;
 708   p_setkatimer(p);
 709   if (kx_init(&p->kx, p, &p->ks))
 710     goto tidy_1;
 711   p->next = peers;
 712   if (peers)
 713     peers->prev = p;
 714   peers = p;
 715   a_notify("ADD",
 716             "?PEER", p,
 717             "%s", p->ifname,
 718             "?ADDR", &p->spec.sa,
 719             A_END);
 720   a_notify("KXSTART", "?PEER", p, A_END);
 721     /* Couldn't tell anyone before */
 722   return (p);
 723
 724 tidy_1:
 725   if (spec->t_ka)
 726     sel_rmtimer(&p->tka);
 727   xfree(p->ifname);
 728   p->t->ops->destroy(p->t);
 729 tidy_0:
 730   xfree(p->spec.name);
 731   DESTROY(p);
 732   return (0);
 733 }
 734
 735 /* --- @p_name@ --- *
 736  *
 737  * Arguments:   @peer *p@ = pointer to a peer block
 738  *
 739  * Returns:     A pointer to the peer's name.
 740  */
 741
 742 const char *p_name(peer *p) { return (p->spec.name); }
 743
 744 /* --- @p_spec@ --- *
 745  *
 746  * Arguments:   @peer *p@ = pointer to a peer block
 747  *
 748  * Returns:     Pointer to the peer's specification
 749  */
 750
 751 const peerspec *p_spec(peer *p) { return (&p->spec); }
 752
 753 /* --- @p_find@ --- *
 754  *
 755  * Arguments:   @const char *name@ = name to look up
 756  *
 757  * Returns:     Pointer to the peer block, or null if not found.
 758  *
 759  * Use:         Finds a peer by name.
 760  */
 761
 762 peer *p_find(const char *name)
 763 {
 764   peer *p;
 765   for (p = peers; p; p = p->next) {
 766     if (strcmp(name, p->spec.name) == 0)
 767       return (p);
 768   }
 769   return (0);
 770 }
 771
 772 /* --- @p_destroy@ --- *
 773  *
 774  * Arguments:   @peer *p@ = pointer to a peer
 775  *
 776  * Returns:     ---
 777  *
 778  * Use:         Destroys a peer.
 779  */
 780
 781 void p_destroy(peer *p)
 782 {
 783   ping *pg, *ppg;
 784
 785   T( trace(T_PEER, "peer: destroying peer `%s'", p->spec.name); )
 786   a_notify("KILL", "%s", p->spec.name, A_END);
 787   ksl_free(&p->ks);
 788   kx_free(&p->kx);
 789   if (p->ifname)
 790     xfree(p->ifname);
 791   p->t->ops->destroy(p->t);
 792   if (p->spec.t_ka)
 793     sel_rmtimer(&p->tka);
 794   for (pg = p->pings; pg; pg = ppg) {
 795     ppg = pg->next;
 796     p_pingdone(pg, PING_PEERDIED);
 797   }
 798   if (p->next)
 799     p->next->prev = p->prev;
 800   if (p->prev)
 801     p->prev->next = p->next;
 802   else
 803     peers = p->next;
 804   DESTROY(p);
 805 }
 806
 807 /* --- @p_first@, @p_next@ --- *
 808  *
 809  * Arguments:   @peer *p@ = a peer block
 810  *
 811  * Returns:     @peer_first@ returns the first peer in some ordering;
 812  *              @peer_next@ returns the peer following a given one in the
 813  *              same ordering.  Null is returned for the end of the list.
 814  */
 815
 816 peer *p_first(void) { return (peers); }
 817 peer *p_next(peer *p) { return (p->next); }
 818
 819 /*----- That's all, folks -------------------------------------------------*/