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 it under
  13  * the terms of the GNU General Public License as published by the Free
  14  * Software Foundation; either version 3 of the License, or (at your
  15  * option) any later version.
  16  *
  17  * TrIPE is distributed in the hope that it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
  24  */
  25
  26 /*----- Header files ------------------------------------------------------*/
  27
  28 #include "tripe.h"
  29
  30 /*----- Global state ------------------------------------------------------*/
  31
  32 udpsocket udpsock[NADDRFAM];
  33
  34 /*----- Static variables --------------------------------------------------*/
  35
  36 static sym_table byname;
  37 static addrmap byaddr;
  38 static unsigned nmobile;
  39 static struct tunnel_node {
  40   struct tunnel_node *next;
  41   const tunnel_ops *tops;
  42 } *tunnels, **tunnels_tail = &tunnels;
  43 static ratelim wgt_limit;
  44 const tunnel_ops *dflttun;
  45
  46 /*----- Main code ---------------------------------------------------------*/
  47
  48 /* --- @p_pingtype@ --- *
  49  *
  50  * Arguments:   @unsigned msg@ = message type
  51  *
  52  * Returns:     String to describe the message.
  53  */
  54
  55 static const char *p_pingtype(unsigned msg)
  56 {
  57   switch (msg & MSG_TYPEMASK) {
  58     case MISC_PING:
  59     case MISC_PONG:
  60       return "transport-ping";
  61     case MISC_EPING:
  62     case MISC_EPONG:
  63       return "encrypted-ping";
  64     default:
  65       abort();
  66   }
  67 }
  68
  69 /* --- @p_ponged@ --- *
  70  *
  71  * Arguments:   @peer *p@ = peer packet arrived from
  72  *              @unsigned msg@ = message type
  73  *              @buf *b@ = buffer containing payload
  74  *
  75  * Returns:     ---
  76  *
  77  * Use:         Processes a ping response.
  78  */
  79
  80 static void p_ponged(peer *p, unsigned msg, buf *b)
  81 {
  82   uint32 id;
  83   const octet *magic;
  84   ping *pg;
  85
  86   IF_TRACING(T_PEER, {
  87     trace(T_PEER, "peer: received %s reply from %s",
  88           p_pingtype(msg), p->spec.name);
  89     trace_block(T_PACKET, "peer: ping contents", BBASE(b), BSZ(b));
  90   })
  91
  92   if (buf_getu32(b, &id) ||
  93       (magic = buf_get(b, sizeof(pg->magic))) == 0 ||
  94       BLEFT(b)) {
  95     a_warn("PEER", "?PEER", p, "malformed-%s", p_pingtype(msg), A_END);
  96     return;
  97   }
  98
  99   for (pg = p->pings; pg; pg = pg->next) {
 100     if (pg->id == id)
 101       goto found;
 102   }
 103   a_warn("PEER",
 104          "?PEER", p,
 105          "unexpected-%s", p_pingtype(msg),
 106          "0x%08lx", (unsigned long)id,
 107          A_END);
 108   return;
 109
 110 found:
 111   if (memcmp(magic, pg->magic, sizeof(pg->magic)) != 0) {
 112     a_warn("PEER", "?PEER", p, "corrupt-%s", p_pingtype(msg), A_END);
 113     return;
 114   }
 115   p_pingdone(pg, PING_OK);
 116 }
 117
 118 /* --- @p_rxupdstats@ --- *
 119  *
 120  * Arguments:   @peer *p@ = peer to update
 121  *              @size_t n@ = size of incoming packet
 122  *
 123  * Returns:     ---
 124  *
 125  * Use:         Updates the peer's incoming packet statistics.
 126  */
 127
 128 static void p_rxupdstats(peer *p, size_t n)
 129 {
 130   p->st.t_last = time(0);
 131   p->st.n_in++;
 132   p->st.sz_in += n;
 133 }
 134
 135 /* --- @p_encrypt@ --- *
 136  *
 137  * Arguments:   @peer *p@ = peer to encrypt message to
 138  *              @int ty@ message type to send
 139  *              @buf *bin, *bout@ = input and output buffers
 140  *
 141  * Returns:     ---
 142  *
 143  * Use:         Convenience function for packet encryption.  Forces
 144  *              renegotiation when necessary.  Check for the output buffer
 145  *              being broken to find out whether the encryption was
 146  *              successful.
 147  */
 148
 149 static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
 150 {
 151   int err = ksl_encrypt(&p->ks, ty, bin, bout);
 152
 153   if (err == KSERR_REGEN) {
 154     kx_start(&p->kx, 1);
 155     err = 0;
 156   }
 157   if (!BOK(bout))
 158     err = -1;
 159   return (err);
 160 }
 161
 162 /* --- @p_updateaddr@ --- *
 163  *
 164  * Arguments:   @peer *p@ = pointer to peer block
 165  *              @const addr *a@ = address to associate with this peer
 166  *
 167  * Returns:     Zero if the address was changed; @+1@ if it was already
 168  *              right.
 169  *
 170  * Use:         Updates our idea of @p@'s address.
 171  */
 172
 173 int p_updateaddr(peer *p, const addr *a)
 174 {
 175   peer *q;
 176   peer_byaddr *pa, *qa;
 177   int ix;
 178   unsigned f;
 179
 180   /* --- Figure out how to proceed --- *
 181    *
 182    * If this address already belongs to a different peer, then swap the
 183    * addresses over.  This doesn't leave the displaced peer in an especially
 184    * good state, but it ought to get sorted out soon enough.
 185    */
 186
 187   pa = am_find(&byaddr, a, sizeof(peer_byaddr), &f);
 188   if (f && pa->p == p)
 189     return (+1);
 190   else if (!f) {
 191     T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
 192     am_remove(&byaddr, p->byaddr);
 193     p->byaddr = pa; p->spec.sa = *a; pa->p = p;
 194     p->afix = afix(p->spec.sa.sa.sa_family); assert(p->afix >= 0);
 195     a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
 196     return (0);
 197   } else {
 198     q = pa->p; qa = p->byaddr;
 199     T( trace(T_PEER, "peer: swapping addresses for `%s' and `%s'",
 200              p_name(p), p_name(q)); )
 201     q->byaddr = qa; qa->p = q; q->spec.sa = p->spec.sa;
 202     p->byaddr = pa; pa->p = p; p->spec.sa = *a;
 203     ix = p->afix; p->afix = q->afix; q->afix = ix;
 204     a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
 205     a_notify("NEWADDR", "?PEER", q, "?ADDR", &q->spec.sa, A_END);
 206     return (0);
 207   }
 208 }
 209
 210 /* --- @p_decrypt@ --- *
 211  *
 212  * Arguments:   @peer **pp@ = pointer to peer to decrypt message from
 213  *              @addr *a@ = address the packet arrived on
 214  *              @size_t n@ = size of original incoming packet
 215  *              @int ty@ = message type to expect
 216  *              @buf *bin, *bout@ = input and output buffers
 217  *
 218  * Returns:     Zero on success; nonzero on error.
 219  *
 220  * Use:         Convenience function for packet decryption.  Reports errors
 221  *              and updates statistics appropriately.
 222  *
 223  *              If @*pp@ is null on entry and there are mobile peers then we
 224  *              see if any of them can decrypt the packet.  If so, we record
 225  *              @*a@ as the peer's new address and send a notification.
 226  */
 227
 228 static int p_decrypt(peer **pp, addr *a, size_t n,
 229                      int ty, buf *bin, buf *bout)
 230 {
 231   peer *p, *q;
 232   int err = KSERR_DECRYPT;
 233   buf b;
 234
 235   /* --- If we have a match on the source address then try that first --- */
 236
 237   q = *pp;
 238   if (q) {
 239     T( trace(T_PEER, "peer: decrypting packet from known peer `%s'",
 240              p_name(q)); )
 241     if ((err = ksl_decrypt(&q->ks, ty, bin, bout)) != KSERR_DECRYPT ||
 242         !(q->spec.f & PSF_MOBILE) || nmobile == 1) {
 243       p = q;
 244       goto match;
 245     }
 246     T( trace(T_PEER, "peer: failed to decrypt: try other mobile peers..."); )
 247   } else if (nmobile)
 248     T( trace(T_PEER, "peer: unknown source: trying mobile peers...") );
 249   else {
 250     p = 0;
 251     goto searched;
 252   }
 253
 254   /* --- See whether any mobile peer is interested --- */
 255
 256   p = 0;
 257   FOREACH_PEER(qq, {
 258     if (qq == q || !(qq->spec.f & PSF_MOBILE)) continue;
 259     if ((err = ksl_decrypt(&qq->ks, ty, bin, bout)) == KSERR_DECRYPT) {
 260       T( trace(T_PEER, "peer: peer `%s' failed to decrypt",
 261                p_name(qq)); )
 262         continue;
 263     } else {
 264       p = qq;
 265       IF_TRACING(T_PEER, {
 266         if (!err)
 267           trace(T_PEER, "peer: peer `%s' reports success", p_name(qq));
 268         else {
 269           trace(T_PEER, "peer: peer `%s' reports decryption error %d",
 270                 p_name(qq), err);
 271         }
 272       })
 273       break;
 274     }
 275   });
 276
 277   /* --- We've searched the mobile peers --- */
 278
 279 searched:
 280   if (!p) {
 281     if (!q) {
 282       a_warn("PEER", "-", "unexpected-source", "?ADDR", a, A_END);
 283       if (!ratelim_withdraw(&wgt_limit, 1)) {
 284         buf_init(&b, buf_t, sizeof(buf_t));
 285         buf_putbyte(&b, MSG_MISC | MISC_WGT);
 286         if (n > WGTLEN) n = WGTLEN;
 287         buf_put(&b, buf_i, n);
 288         T( trace(T_PEER, "peer: sending who-goes-there message"); )
 289         assert(BOK(&b)); p_txaddr(a, BBASE(&b), BLEN(&b));
 290       }
 291     } else {
 292       a_warn("PEER", "?PEER", p, "decrypt-failed",
 293              "error-code", "%d", err, A_END);
 294       p_rxupdstats(q, n);
 295     }
 296     return (-1);
 297   }
 298
 299   /* --- We found one that accepted, so update the peer's address --- */
 300
 301   if (!err) {
 302     *pp = p;
 303     p_updateaddr(p, a);
 304   }
 305
 306 match:
 307   p_rxupdstats(p, n);
 308   if (err) {
 309     if (p) p->st.n_reject++;
 310     a_warn("PEER", "?PEER", p, "decrypt-failed",
 311            "error-code", "%d", err, A_END);
 312     return (-1);
 313   }
 314   if (!BOK(bout))
 315     return (-1);
 316   return (0);
 317 }
 318
 319 /* --- @p_read@ --- *
 320  *
 321  * Arguments:   @int fd@ = file descriptor to read from
 322  *              @unsigned mode@ = what happened
 323  *              @void *v@ = an uninteresting pointer
 324  *
 325  * Returns:     ---
 326  *
 327  * Use:         Reads a packet from somewhere.
 328  */
 329
 330 static void p_read(int fd, unsigned mode, void *v)
 331 {
 332   peer *p = 0;
 333   addr a;
 334   socklen_t sz;
 335   ssize_t n;
 336   int ch;
 337   buf b, bb;
 338   const octet *q;
 339   unsigned i;
 340   time_t now;
 341 #ifndef NTRACE
 342   int ix = -1;
 343   char name[NI_MAXHOST], svc[NI_MAXSERV];
 344 #endif
 345
 346   /* --- Read the data --- */
 347
 348   QUICKRAND;
 349   sz = sizeof(addr);
 350   n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
 351   if (n < 0) {
 352     a_warn("PEER", "-", "socket-read-error", "?ERRNO", A_END);
 353     return;
 354   }
 355   IF_TRACING(T_PEER, {
 356     ix = afix(a.sa.sa_family);
 357     getnameinfo(&a.sa, sz, name, sizeof(name), svc, sizeof(svc),
 358                 NI_NUMERICHOST | NI_NUMERICSERV);
 359   })
 360
 361   /* --- If the packet is a greeting, don't check peers --- */
 362
 363   if (n && buf_i[0] == (MSG_MISC | MISC_GREET)) {
 364     IF_TRACING(T_PEER, {
 365       trace(T_PEER, "peer: greeting received from %s %s %s",
 366             aftab[ix].name, name, svc);
 367       trace_block(T_PACKET, "peer: greeting contents", buf_i, n);
 368     })
 369     buf_init(&b, buf_i, n);
 370     buf_getbyte(&b);
 371     if (c_check(0, 0, &b) || BLEFT(&b)) {
 372       a_warn("PEER", "-", "invalid-greeting", A_END);
 373       return;
 374     }
 375     a_notify("GREET",
 376              "?B64", buf_i + 1, (size_t)(n - 1),
 377              "?ADDR", &a,
 378              A_END);
 379     return;
 380   }
 381
 382   /* --- Find the appropriate peer --- *
 383    *
 384    * At this stage, don't worry too much about whether we actually found it.
 385    */
 386
 387   p = p_findbyaddr(&a);
 388
 389   IF_TRACING(T_PEER, {
 390     if (p) {
 391       trace(T_PEER,
 392             "peer: packet received from `%s' from address %s %s %s",
 393             p_name(p), aftab[ix].name, name, svc);
 394     } else {
 395       trace(T_PEER, "peer: packet received from unknown address %s %s %s",
 396             aftab[ix].name, name, svc);
 397     }
 398     trace_block(T_PACKET, "peer: packet contents", buf_i, n);
 399   })
 400
 401   /* --- Pick the packet apart --- */
 402
 403   buf_init(&b, buf_i, n);
 404   if ((ch = buf_getbyte(&b)) < 0) {
 405     a_warn("PEER", "?PEER", p, "bad-packet", "no-type", A_END);
 406     return;
 407   }
 408   switch (ch & MSG_CATMASK) {
 409     case MSG_PACKET:
 410       if (ch & MSG_TYPEMASK) {
 411         a_warn("PEER",
 412                "?PEER", p,
 413                "bad-packet",
 414                "unknown-type", "0x%02x", ch,
 415                A_END);
 416         if (p) p->st.n_reject++;
 417         return;
 418       }
 419       buf_init(&bb, buf_o, sizeof(buf_o));
 420       if (p_decrypt(&p, &a, n, MSG_PACKET, &b, &bb))
 421         return;
 422       if (BOK(&bb)) {
 423         p->st.n_ipin++;
 424         p->st.sz_ipin += BSZ(&b);
 425         p->t->ops->inject(p->t, &bb);
 426       } else {
 427         p->st.n_reject++;
 428         a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
 429       }
 430       break;
 431     case MSG_KEYEXCH:
 432       if (p) p_rxupdstats(p, n);
 433       if (kx_message(p ? &p->kx : 0, &a, ch & MSG_TYPEMASK, &b)) goto unexp;
 434       break;
 435     case MSG_MISC:
 436       switch (ch & MSG_TYPEMASK) {
 437         case MISC_NOP:
 438           if (!p) goto unexp;
 439           p_rxupdstats(p, n);
 440           T( trace(T_PEER, "peer: received NOP packet"); )
 441           break;
 442         case MISC_PING:
 443           if (!p) goto unexp;
 444           p_rxupdstats(p, n);
 445           buf_put(p_txstart(p, MSG_MISC | MISC_PONG), BCUR(&b), BLEFT(&b));
 446           p_txend(p, 0);
 447           break;
 448         case MISC_PONG:
 449           if (!p) goto unexp;
 450           p_rxupdstats(p, n);
 451           p_ponged(p, MISC_PONG, &b);
 452           break;
 453         case MISC_EPING:
 454           buf_init(&bb, buf_t, sizeof(buf_t));
 455           if (p_decrypt(&p, &a, n, ch, &b, &bb))
 456             return;
 457           if (BOK(&bb)) {
 458             buf_flip(&bb);
 459             p_encrypt(p, MSG_MISC | MISC_EPONG, &bb,
 460                       p_txstart(p, MSG_MISC | MISC_EPONG));
 461             p_txend(p, TXF_WGT);
 462           }
 463           break;
 464         case MISC_EPONG:
 465           buf_init(&bb, buf_t, sizeof(buf_t));
 466           if (p_decrypt(&p, &a, n, ch, &b, &bb))
 467             return;
 468           if (BOK(&bb)) {
 469             buf_flip(&bb);
 470             p_ponged(p, MISC_EPONG, &bb);
 471           }
 472           break;
 473         case MISC_BYE:
 474           buf_init(&bb, buf_t, sizeof(buf_t));
 475           if (p_decrypt(&p, &a, n, ch, &b, &bb)) return;
 476           if (!(p->spec.f&PSF_EPHEM)) return;
 477           if (BOK(&bb)) {
 478             buf_flip(&bb);
 479             if (BSZ(&bb)) return;
 480             p_destroy(p, 0);
 481           }
 482           break;
 483         case MISC_WGT:
 484           if (!p) goto unexp;
 485           if (!(p->spec.f&PSF_EPHEM))
 486             { a_warn("PEER", "?PEER", p, "unexpected-wgt", A_END); break; }
 487           n = BLEFT(&b); if (n > WGTLEN) n = WGTLEN;
 488           now = time(0);
 489           q = buf_get(&b, n); assert(q);
 490           for (i = 0; i < NWGT; i++) {
 491             if (p->wgt[i].when != (time_t)-1 &&
 492                 now - p->wgt[i].when <= T_WGT &&
 493                 p->wgt[i].sz == n &&
 494                 MEMCMP(p->wgt[i].msg, ==, q, n))
 495               goto found_wgt;
 496           }
 497           a_warn("PEER", "?PEER", p, "unrecognized-wgt", A_END);
 498           break;
 499         found_wgt:
 500           if (p->spec.knock) {
 501             T( trace(T_PEER, "peer: who-goes-there from peer: knocking"); )
 502             kx_start(&p->kx, 0);
 503           } else {
 504             T( trace(T_PEER, "peer: who-goes-there from peer: notifying"); )
 505             a_notify("WGT", "?PEER", p, A_END);
 506           }
 507           break;
 508       }
 509       break;
 510     default:
 511       if (p) p->st.n_reject++;
 512       a_warn("PEER",
 513              "?PEER", p,
 514              "bad-packet",
 515              "unknown-category", "0x%02x", ch,
 516              A_END);
 517       break;
 518     unexp:
 519       a_warn("PEER", "-", "unexpected-source", "?ADDR", &a, A_END);
 520       break;
 521   }
 522 }
 523
 524 /* --- @p_txstart@ --- *
 525  *
 526  * Arguments:   @peer *p@ = pointer to peer block
 527  *              @unsigned msg@ = message type code
 528  *
 529  * Returns:     A pointer to a buffer to write to.
 530  *
 531  * Use:         Starts sending to a peer.  Only one send can happen at a
 532  *              time.
 533  */
 534
 535 buf *p_txstart(peer *p, unsigned msg)
 536 {
 537   buf_init(&p->b, buf_o, sizeof(buf_o));
 538   buf_putbyte(&p->b, msg);
 539   return (&p->b);
 540 }
 541
 542 /* --- @p_txaddr@ --- *
 543  *
 544  * Arguments:   @const addr *a@ = recipient address
 545  *              @const void *p@ = pointer to packet to send
 546  *              @size_t sz@ = length of packet
 547  *
 548  * Returns:     Zero if successful, nonzero on error.
 549  *
 550  * Use:         Sends a packet to an address which (possibly) isn't a current
 551  *              peer.
 552  */
 553
 554 int p_txaddr(const addr *a, const void *p, size_t sz)
 555 {
 556   socklen_t sasz = addrsz(a);
 557   int i;
 558
 559   if ((i = afix(a->sa.sa_family)) < 0) {
 560     a_warn("PEER", "?ADDR", a, "disabled-address-family", A_END);
 561     return (-1);
 562   }
 563   IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet", p, sz); )
 564   if (sendto(udpsock[i].sf.fd, p, sz, 0, &a->sa, sasz) < 0) {
 565     a_warn("PEER", "?ADDR", a, "socket-write-error", "?ERRNO", A_END);
 566     return (-1);
 567   }
 568   return (0);
 569 }
 570
 571 /* --- @p_txend@ --- *
 572  *
 573  * Arguments:   @peer *p@ = pointer to peer block
 574  *              @unsigned f@ = flags
 575  *
 576  * Returns:     ---
 577  *
 578  * Use:         Sends a packet to the peer.
 579  */
 580
 581 static void p_setkatimer(peer *);
 582
 583 static int p_dotxend(peer *p)
 584 {
 585   socklen_t sasz = addrsz(&p->spec.sa);
 586
 587   if (!BOK(&p->b)) {
 588     a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
 589     return (0);
 590   }
 591   IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
 592                                  BBASE(&p->b), BLEN(&p->b)); )
 593   if (sendto(udpsock[p->afix].sf.fd, BBASE(&p->b), BLEN(&p->b),
 594              0, &p->spec.sa.sa, sasz) < 0) {
 595     a_warn("PEER", "?PEER", p, "socket-write-error", "?ERRNO", A_END);
 596     return (0);
 597   } else {
 598     p->st.n_out++;
 599     p->st.sz_out += BLEN(&p->b);
 600     return (1);
 601   }
 602 }
 603
 604 void p_txend(peer *p, unsigned f)
 605 {
 606   size_t n;
 607
 608   if (p_dotxend(p)) {
 609     if ((f&TXF_WGT) && (p->spec.f&PSF_EPHEM)) {
 610       n = BLEN(&p->b); if (n > WGTLEN) n = WGTLEN;
 611       memcpy(p->wgt[p->wgtix].msg, BBASE(&p->b), n);
 612       p->wgt[p->wgtix].sz = n;
 613       p->wgt[p->wgtix].when = time(0);
 614       p->wgtix++; if (p->wgtix >= NWGT) p->wgtix = 0;
 615     }
 616     if (p->spec.t_ka) {
 617       sel_rmtimer(&p->tka);
 618       p_setkatimer(p);
 619     }
 620   }
 621 }
 622
 623 /* --- @p_pingwrite@ --- *
 624  *
 625  * Arguments:   @ping *p@ = ping structure
 626  *              @buf *b@ = buffer to write in
 627  *
 628  * Returns:     ---
 629  *
 630  * Use:         Fills in a ping structure and writes the packet payload.
 631  */
 632
 633 static void p_pingwrite(ping *p, buf *b)
 634 {
 635   static uint32 seq = 0;
 636
 637   p->id = U32(seq++);
 638   GR_FILL(&rand_global, p->magic, sizeof(p->magic));
 639   buf_putu32(b, p->id);
 640   buf_put(b, p->magic, sizeof(p->magic));
 641 }
 642
 643 /* --- @p_pingdone@ --- *
 644  *
 645  * Arguments:   @ping *p@ = ping structure
 646  *              @int rc@ = return code to pass on
 647  *
 648  * Returns:     ---
 649  *
 650  * Use:         Disposes of a ping structure, maybe sending a notification.
 651  */
 652
 653 void p_pingdone(ping *p, int rc)
 654 {
 655   if (p->prev) p->prev->next = p->next;
 656   else p->p->pings = p->next;
 657   if (p->next) p->next->prev = p->prev;
 658   if (rc != PING_TIMEOUT) sel_rmtimer(&p->t);
 659   T( trace(T_PEER, "peer: ping 0x%08lx done (rc = %d)",
 660            (unsigned long)p->id, rc); )
 661   if (rc >= 0) p->func(rc, p->arg);
 662 }
 663
 664 /* --- @p_pingtimeout@ --- *
 665  *
 666  * Arguments:   @struct timeval *now@ = the time now
 667  *              @void *pv@ = pointer to ping block
 668  *
 669  * Returns:     ---
 670  *
 671  * Use:         Called when a ping times out.
 672  */
 673
 674 static void p_pingtimeout(struct timeval *now, void *pv)
 675 {
 676   ping *p = pv;
 677
 678   T( trace(T_PEER, "peer: ping 0x%08lx timed out", (unsigned long)p->id); )
 679   p_pingdone(p, PING_TIMEOUT);
 680 }
 681
 682 /* --- @p_pingsend@ --- *
 683  *
 684  * Arguments:   @peer *p@ = destination peer
 685  *              @ping *pg@ = structure to fill in
 686  *              @unsigned type@ = message type
 687  *              @unsigned long timeout@ = how long to wait before giving up
 688  *              @void (*func)(int, void *)@ = callback function
 689  *              @void *arg@ = argument for callback
 690  *
 691  * Returns:     Zero if successful, nonzero if it failed.
 692  *
 693  * Use:         Sends a ping to a peer.  Call @func@ with a nonzero argument
 694  *              if we get an answer within the timeout, or zero if no answer.
 695  */
 696
 697 int p_pingsend(peer *p, ping *pg, unsigned type,
 698                unsigned long timeout,
 699                void (*func)(int, void *), void *arg)
 700 {
 701   buf *b, bb;
 702   struct timeval tv;
 703
 704   switch (type) {
 705     case MISC_PING:
 706       pg->msg = MISC_PONG;
 707       b = p_txstart(p, MSG_MISC | MISC_PING);
 708       p_pingwrite(pg, b);
 709       p_txend(p, 0);
 710       break;
 711     case MISC_EPING:
 712       pg->msg = MISC_EPONG;
 713       b = p_txstart(p, MSG_MISC | MISC_EPING);
 714       buf_init(&bb, buf_t, sizeof(buf_t));
 715       p_pingwrite(pg, &bb);
 716       buf_flip(&bb);
 717       p_encrypt(p, MSG_MISC | MISC_EPING, &bb, b);
 718       if (!BOK(b))
 719         return (-1);
 720       p_txend(p, TXF_WGT);
 721       break;
 722     default:
 723       abort();
 724       break;
 725   }
 726
 727   pg->next = p->pings;
 728   pg->prev = 0;
 729   pg->p = p;
 730   pg->func = func;
 731   pg->arg = arg;
 732   if (p->pings) p->pings->prev = pg;
 733   p->pings = pg;
 734   gettimeofday(&tv, 0);
 735   tv.tv_sec += timeout;
 736   sel_addtimer(&sel, &pg->t, &tv, p_pingtimeout, pg);
 737   T( trace(T_PEER, "peer: send %s 0x%08lx to %s",
 738            p_pingtype(type), (unsigned long)pg->id, p->spec.name); )
 739   return (0);
 740 }
 741
 742 /* --- @p_greet@ --- *
 743  *
 744  * Arguments:   @peer *p@ = peer to send to
 745  *              @const void *c@ = pointer to challenge
 746  *              @size_t sz@ = size of challenge
 747  *
 748  * Returns:     ---
 749  *
 750  * Use:         Sends a greeting packet.
 751  */
 752
 753 void p_greet(peer *p, const void *c, size_t sz)
 754 {
 755   buf *b = p_txstart(p, MSG_MISC | MISC_GREET);
 756   buf_put(b, c, sz);
 757   p_txend(p, 0);
 758 }
 759
 760 /* --- @p_tun@ --- *
 761  *
 762  * Arguments:   @peer *p@ = pointer to peer block
 763  *              @buf *b@ = buffer containing incoming packet
 764  *
 765  * Returns:     ---
 766  *
 767  * Use:         Handles a packet which needs to be sent to a peer.
 768  */
 769
 770 void p_tun(peer *p, buf *b)
 771 {
 772   buf *bb = p_txstart(p, MSG_PACKET);
 773
 774   QUICKRAND;
 775   p_encrypt(p, MSG_PACKET, b, bb);
 776   if (BOK(bb) && BLEN(bb)) {
 777     p->st.n_ipout++;
 778     p->st.sz_ipout += BLEN(bb);
 779     p_txend(p, TXF_WGT);
 780   }
 781 }
 782
 783 /* --- @p_keyreload@ --- *
 784  *
 785  * Arguments:   ---
 786  *
 787  * Returns:     ---
 788  *
 789  * Use:         Forces a check of the daemon's keyring files.
 790  */
 791
 792 void p_keyreload(void)
 793 {
 794   if (km_reload())
 795     FOREACH_PEER(p, { kx_newkeys(&p->kx); });
 796 }
 797
 798 /* --- @p_interval@ --- *
 799  *
 800  * Arguments:   ---
 801  *
 802  * Returns:     ---
 803  *
 804  * Use:         Called periodically to do tidying.
 805  */
 806
 807 void p_interval(void)
 808 {
 809   p_keyreload();
 810   FOREACH_PEER(p, { ksl_prune(&p->ks); });
 811 }
 812
 813 /* --- @p_stats@ --- *
 814  *
 815  * Arguments:   @peer *p@ = pointer to a peer block
 816  *
 817  * Returns:     A pointer to the peer's statistics.
 818  */
 819
 820 stats *p_stats(peer *p) { return (&p->st); }
 821
 822 /* --- @p_ifname@ --- *
 823  *
 824  * Arguments:   @peer *p@ = pointer to a peer block
 825  *
 826  * Returns:     A pointer to the peer's interface name.
 827  */
 828
 829 const char *p_ifname(peer *p) { return (p->ifname); }
 830
 831 /* --- @p_setifname@ --- *
 832  *
 833  * Arguments:   @peer *p@ = pointer to a peer block
 834  *              @const char *name@ = pointer to the new name
 835  *
 836  * Returns:     ---
 837  *
 838  * Use:         Changes the name held for a peer's interface.
 839  */
 840
 841 void p_setifname(peer *p, const char *name)
 842 {
 843   xfree(p->ifname);
 844   p->ifname = xstrdup(name);
 845   if (p->spec.tops->setifname)
 846     p->spec.tops->setifname(p->t, name);
 847 }
 848
 849 /* --- @p_addr@ --- *
 850  *
 851  * Arguments:   @peer *p@ = pointer to a peer block
 852  *
 853  * Returns:     A pointer to the peer's address.
 854  */
 855
 856 const addr *p_addr(peer *p) { return (&p->spec.sa); }
 857
 858 /* --- @p_bind@ --- *
 859  *
 860  * Arguments:   @struct addrinfo *ailist@ = addresses to bind to
 861  *
 862  * Returns:     Zero on success, @-1@ on failure.
 863  *
 864  * Use:         Binds to the main UDP sockets.
 865  */
 866
 867 int p_bind(struct addrinfo *ailist)
 868 {
 869   int fd = -1;
 870   int len = PKBUFSZ;
 871   int yes = 1;
 872   int i;
 873   struct addrinfo *ai;
 874   unsigned port, lastport = 0;
 875   addr a;
 876   socklen_t sz;
 877
 878   for (i = 0; i < NADDRFAM; i++) udpsock[i].sf.fd = -1;
 879
 880   for (ai = ailist; ai; ai = ai->ai_next) {
 881     if ((i = afix(ai->ai_family)) < 0) continue;
 882     if (udpsock[i].sf.fd != -1) continue;
 883
 884     /* --- Note on socket buffer sizes --- *
 885      *
 886      * For some bizarre reason, Linux 2.2 (at least) doubles the socket
 887      * buffer sizes I pass to @setsockopt@.  I'm not putting special-case
 888      * code here for Linux: BSD (at least TCPv2) does what I tell it rather
 889      * than second-guessing me.
 890      */
 891
 892     if ((fd = socket(ai->ai_family, SOCK_DGRAM, 0)) < 0) {
 893       a_warn("PEER", "-", "udp-socket", "%s", aftab[i].name,
 894              "create-failed", "?ERRNO", A_END);
 895       goto fail;
 896     }
 897     if (i == AFIX_INET6 &&
 898         setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &yes, sizeof(yes))) {
 899       a_warn("PEER", "-", "udp-socket", "%s", aftab[i].name,
 900              "set-v6only-failed", "?ERRNO", A_END);
 901       goto fail;
 902     }
 903     assert(ai->ai_addrlen <= sizeof(a));
 904     memcpy(&a, ai->ai_addr, ai->ai_addrlen);
 905     if ((port = getport(&a)) == 0 && lastport) setport(&a, lastport);
 906     if (bind(fd, &a.sa, addrsz(&a))) {
 907       a_warn("PEER", "-", "udp-socket", "%s", aftab[i].name,
 908              "bind-failed", "?ERRNO", A_END);
 909       goto fail;
 910     }
 911     if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
 912         setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) {
 913       a_warn("PEER", "-", "udp-socket", "%s", aftab[i].name,
 914              "set-buffers-failed", "?ERRNO", A_END);
 915       goto fail;
 916     }
 917     fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 918     if (port)
 919       udpsock[i].port = port;
 920     else {
 921       sz = sizeof(a);
 922       if (getsockname(fd, &a.sa, &sz)) {
 923         a_warn("PEER", "-", "udp-socket", "%s", aftab[i].name,
 924                "read-local-address-failed", "?ERRNO", A_END);
 925         goto fail;
 926       }
 927       udpsock[i].port = lastport = getport(&a);
 928     }
 929     T( trace(T_PEER, "peer: created %s socket", aftab[i].name); )
 930     sel_initfile(&sel, &udpsock[i].sf, fd, SEL_READ, p_read, 0);
 931     sel_addfile(&udpsock[i].sf);
 932     fd = -1;
 933   }
 934
 935   return (0);
 936
 937 fail:
 938   if (fd != -1) close(fd);
 939   p_unbind();
 940   return (-1);
 941 }
 942
 943 /* --- @p_unbind@ --- *
 944  *
 945  * Arguments:   ---
 946  *
 947  * Returns:     ---
 948  *
 949  * Use:         Unbinds the UDP sockets.  There must not be any active peers,
 950  *              and none can be created until the sockets are rebound.
 951  */
 952
 953 void p_unbind(void)
 954 {
 955   int i;
 956
 957 #ifndef NDEBUG
 958   { peer_iter it; p_mkiter(&it); assert(!p_next(&it)); }
 959 #endif
 960
 961   for (i = 0; i < NADDRFAM; i++) {
 962     if (udpsock[i].sf.fd == -1) continue;
 963     sel_rmfile(&udpsock[i].sf);
 964     close(udpsock[i].sf.fd);
 965     udpsock[i].sf.fd = -1;
 966   }
 967 }
 968
 969 /* --- @p_init@ --- *
 970  *
 971  * Arguments:   ---
 972  *
 973  * Returns:     ---
 974  *
 975  * Use:         Initializes the peer system.
 976  */
 977
 978 void p_init(void)
 979 {
 980   sym_create(&byname);
 981   am_create(&byaddr);
 982   ratelim_init(&wgt_limit, 5, 100);
 983 }
 984
 985 /* --- @p_addtun@ --- *
 986  *
 987  * Arguments:   @const tunnel_ops *tops@ = tunnel ops to add
 988  *
 989  * Returns:     Zero on success, @-1@ on failure.
 990  *
 991  * Use:         Adds a tunnel class to the list of known classes, if it
 992  *              initializes properly.  If there is no current default tunnel,
 993  *              then this one is made the default.
 994  *
 995  *              Does nothing if the tunnel class is already known.  So adding
 996  *              a bunch of tunnels takes quadratic time, but there will be
 997  *              too few to care about.
 998  */
 999
1000 int p_addtun(const tunnel_ops *tops)
1001 {
1002   struct tunnel_node *tn;
1003
1004   for (tn = tunnels; tn; tn = tn->next)
1005     if (tn->tops == tops) return (0);
1006   if (tops->init()) return (-1);
1007   tn = CREATE(struct tunnel_node);
1008   tn->next = 0; tn->tops = tops;
1009   *tunnels_tail = tn; tunnels_tail = &tn->next;
1010   if (!dflttun) dflttun = tops;
1011   return (0);
1012 }
1013
1014 /* --- @p_setdflttun@ --- *
1015  *
1016  * Arguments:   @const tunnel_ops *tops@ = tunnel ops to set
1017  *
1018  * Returns:     ---
1019  *
1020  * Use:         Sets the default tunnel.  It must already be registered.  The
1021  *              old default is forgotten.
1022  */
1023
1024 void p_setdflttun(const tunnel_ops *tops)
1025   { dflttun = tops; }
1026
1027 /* --- @p_dflttun@ --- *
1028  *
1029  * Arguments:   ---
1030  *
1031  * Returns:     A pointer to the current default tunnel operations, or null
1032  *              if no tunnels are defined.
1033  */
1034
1035 const tunnel_ops *p_dflttun(void) { return (dflttun); }
1036
1037 /* --- @p_findtun@ --- *
1038  *
1039  * Arguments:   @const char *name@ = tunnel name
1040  *
1041  * Returns:     Pointer to the tunnel operations, or null.
1042  *
1043  * Use:         Finds the operations for a named tunnel class.
1044  */
1045
1046 const tunnel_ops *p_findtun(const char *name)
1047 {
1048   const struct tunnel_node *tn;
1049
1050   for (tn = tunnels; tn; tn = tn->next)
1051     if (mystrieq(tn->tops->name, name) == 0) return (tn->tops);
1052   return (0);
1053 }
1054
1055 /* --- @p_mktuniter@ --- *
1056  *
1057  * Arguments:   @tuniter *i@ = pointer to iterator to initialize
1058  *
1059  * Returns:     ---
1060  *
1061  * Use:         Initializes a tunnel iterator.
1062  */
1063
1064 void p_mktuniter(tun_iter *i) { i->next = tunnels; }
1065
1066 /* --- @p_nexttun@ --- *
1067  *
1068  * Arguments:   @tuniter *i@ = pointer to iterator
1069  *
1070  * Returns:     Pointer to the next tunnel's operations, or null.
1071  */
1072
1073 const tunnel_ops *p_nexttun(tun_iter *i)
1074 {
1075   const struct tunnel_node *tn = i->next;
1076
1077   if (!tn) return (0);
1078   else { i->next = tn->next; return (tn->tops); }
1079 }
1080
1081 /* --- @p_keepalive@ --- *
1082  *
1083  * Arguments:   @struct timeval *now@ = the current time
1084  *              @void *pv@ = peer to wake up
1085  *
1086  * Returns:     ---
1087  *
1088  * Use:         Sends a keepalive ping message to its peer.
1089  */
1090
1091 static void p_keepalive(struct timeval *now, void *pv)
1092 {
1093   peer *p = pv;
1094
1095   p_txstart(p, MSG_MISC | MISC_NOP); p_dotxend(p);
1096   T( trace(T_PEER, "peer: sent keepalive to %s", p->spec.name); )
1097   p_setkatimer(p);
1098 }
1099
1100 /* --- @p_setkatimer@ --- *
1101  *
1102  * Arguments:   @peer *p@ = peer to set
1103  *
1104  * Returns:     ---
1105  *
1106  * Use:         Resets the keepalive timer thing.
1107  */
1108
1109 static void p_setkatimer(peer *p)
1110 {
1111   struct timeval tv;
1112
1113   if (!p->spec.t_ka)
1114     return;
1115   gettimeofday(&tv, 0);
1116   tv.tv_sec += p->spec.t_ka;
1117   sel_addtimer(&sel, &p->tka, &tv, p_keepalive, p);
1118 }
1119
1120 /* --- @p_create@ --- *
1121  *
1122  * Arguments:   @peerspec *spec@ = information about this peer
1123  *
1124  * Returns:     Pointer to the peer block, or null if it failed.
1125  *
1126  * Use:         Creates a new named peer block.  No peer is actually attached
1127  *              by this point.
1128  */
1129
1130 peer *p_create(peerspec *spec)
1131 {
1132   peer *p = CREATE(peer);
1133   const tunnel_ops *tops = spec->tops;
1134   int fd;
1135   unsigned f, i;
1136
1137   p->byname = sym_find(&byname, spec->name, -1, sizeof(peer_byname), &f);
1138   if (f) goto tidy_0;
1139   p->byaddr = am_find(&byaddr, &spec->sa, sizeof(peer_byaddr), &f);
1140   if (f) goto tidy_1;
1141   p->byname->p = p->byaddr->p = p;
1142
1143   T( trace(T_PEER, "peer: creating new peer `%s'", spec->name); )
1144   p->spec = *spec;
1145   p->spec.name = (/*unconst*/ char *)SYM_NAME(p->byname);
1146   if (spec->tag) p->spec.tag = xstrdup(spec->tag);
1147   if (spec->privtag) p->spec.privtag = xstrdup(spec->privtag);
1148   if (spec->knock) p->spec.knock = xstrdup(spec->knock);
1149   p->ks = 0;
1150   p->pings = 0;
1151   p->ifname = 0;
1152   p->afix = afix(p->spec.sa.sa.sa_family); assert(p->afix >= 0);
1153   memset(&p->st, 0, sizeof(stats));
1154   p->st.t_start = time(0);
1155   if (!(tops->flags & TUNF_PRIVOPEN))
1156     fd = -1;
1157   else if ((fd = ps_tunfd(tops, &p->ifname)) < 0)
1158     goto tidy_2;
1159   if ((p->t = tops->create(p, fd, &p->ifname)) == 0)
1160     goto tidy_3;
1161   T( trace(T_TUNNEL, "peer: attached interface %s to peer `%s'",
1162            p->ifname, p_name(p)); )
1163   p_setkatimer(p);
1164   iv_addreason();
1165   if (kx_setup(&p->kx, p, &p->ks, p->spec.f & PSF_KXMASK))
1166     goto tidy_4;
1167   a_notify("ADD",
1168            "?PEER", p,
1169            "%s", p->ifname,
1170            "?ADDR", &p->spec.sa,
1171            A_END);
1172   if (!(p->spec.f & KXF_CORK)) {
1173     a_notify("KXSTART", "?PEER", p, A_END);
1174     /* Couldn't tell anyone before */
1175   }
1176   if (p->spec.f & PSF_MOBILE) nmobile++;
1177   for (i = 0; i < NWGT; i++) {
1178     p->wgt[i].sz = 0;
1179     p->wgt[i].when = (time_t)-1;
1180   }
1181   p->wgtix = 0;
1182   return (p);
1183
1184 tidy_4:
1185   if (spec->t_ka) sel_rmtimer(&p->tka);
1186   xfree(p->ifname);
1187   p->t->ops->destroy(p->t);
1188   iv_rmreason();
1189 tidy_3:
1190   if (fd >= 0) close(fd);
1191 tidy_2:
1192   am_remove(&byaddr, p->byaddr);
1193   if (p->spec.tag) xfree(p->spec.tag);
1194   if (p->spec.privtag) xfree(p->spec.privtag);
1195 tidy_1:
1196   sym_remove(&byname, p->byname);
1197 tidy_0:
1198   DESTROY(p);
1199   return (0);
1200 }
1201
1202 /* --- @p_name@ --- *
1203  *
1204  * Arguments:   @peer *p@ = pointer to a peer block
1205  *
1206  * Returns:     A pointer to the peer's name.
1207  */
1208
1209 const char *p_name(peer *p)
1210   { if (p) return (p->spec.name); else return ("-"); }
1211
1212 /* --- @p_tag@ --- *
1213  *
1214  * Arguments:   @peer *p@ = pointer to a peer block
1215  *
1216  * Returns:     A pointer to the peer's public key tag.
1217  */
1218
1219 const char *p_tag(peer *p)
1220   { return (p->spec.tag ? p->spec.tag : p->spec.name); }
1221
1222 /* --- @p_privtag@ --- *
1223  *
1224  * Arguments:   @peer *p@ = pointer to a peer block
1225  *
1226  * Returns:     A pointer to the peer's private key tag.
1227  */
1228
1229 const char *p_privtag(peer *p)
1230   { return (p->spec.privtag ? p->spec.privtag : tag_priv); }
1231
1232 /* --- @p_spec@ --- *
1233  *
1234  * Arguments:   @peer *p@ = pointer to a peer block
1235  *
1236  * Returns:     Pointer to the peer's specification
1237  */
1238
1239 const peerspec *p_spec(peer *p) { return (&p->spec); }
1240
1241 /* --- @p_findbyaddr@ --- *
1242  *
1243  * Arguments:   @const addr *a@ = address to look up
1244  *
1245  * Returns:     Pointer to the peer block, or null if not found.
1246  *
1247  * Use:         Finds a peer by address.
1248  */
1249
1250 peer *p_findbyaddr(const addr *a)
1251 {
1252   peer_byaddr *pa;
1253
1254   if ((pa = am_find(&byaddr, a, 0, 0)) != 0) {
1255     assert(pa->p);
1256     return (pa->p);
1257   }
1258   return (0);
1259 }
1260
1261 /* --- @p_find@ --- *
1262  *
1263  * Arguments:   @const char *name@ = name to look up
1264  *
1265  * Returns:     Pointer to the peer block, or null if not found.
1266  *
1267  * Use:         Finds a peer by name.
1268  */
1269
1270 peer *p_find(const char *name)
1271 {
1272   peer_byname *pn;
1273
1274   if ((pn = sym_find(&byname, name, -1, 0, 0)) != 0)
1275     return (pn->p);
1276   return (0);
1277 }
1278
1279 /* --- @p_destroy@ --- *
1280  *
1281  * Arguments:   @peer *p@ = pointer to a peer
1282  *              @int bye@ = say goodbye to the peer?
1283  *
1284  * Returns:     ---
1285  *
1286  * Use:         Destroys a peer.
1287  */
1288
1289 void p_destroy(peer *p, int bye)
1290 {
1291   ping *pg, *ppg;
1292   buf *b, bb;
1293
1294   T( trace(T_PEER, "peer: destroying peer `%s'", p->spec.name); )
1295
1296   if (bye) {
1297     b = p_txstart(p, MSG_MISC | MISC_BYE);
1298     buf_init(&bb, buf_t, sizeof(buf_t));
1299     assert(BOK(&bb)); buf_flip(&bb);
1300     p_encrypt(p, MSG_MISC | MISC_BYE, &bb, b);
1301     p_txend(p, 0);
1302   }
1303
1304   a_notify("KILL", "%s", p->spec.name, A_END);
1305   ksl_free(&p->ks);
1306   kx_free(&p->kx);
1307   if (p->spec.f & PSF_MOBILE) nmobile--;
1308   if (p->ifname) xfree(p->ifname);
1309   if (p->spec.tag) xfree(p->spec.tag);
1310   if (p->spec.privtag) xfree(p->spec.privtag);
1311   if (p->spec.knock) xfree(p->spec.knock);
1312   p->t->ops->destroy(p->t);
1313   if (p->spec.t_ka) sel_rmtimer(&p->tka);
1314   for (pg = p->pings; pg; pg = ppg) {
1315     ppg = pg->next;
1316     p_pingdone(pg, PING_PEERDIED);
1317   }
1318   sym_remove(&byname, p->byname);
1319   am_remove(&byaddr, p->byaddr);
1320   iv_rmreason();
1321   DESTROY(p);
1322 }
1323
1324 /* --- @p_destroyall@ --- *
1325  *
1326  * Arguments:   ---
1327  *
1328  * Returns:     ---
1329  *
1330  * Use:         Destroys all of the peers, saying goodbye.
1331  */
1332
1333 void p_destroyall(void) { FOREACH_PEER(p, { p_destroy(p, 1); }); }
1334
1335 /* --- @p_mkiter@ --- *
1336  *
1337  * Arguments:   @peer_iter *i@ = pointer to an iterator
1338  *
1339  * Returns:     ---
1340  *
1341  * Use:         Initializes the iterator.
1342  */
1343
1344 void p_mkiter(peer_iter *i) { sym_mkiter(&i->i, &byname); }
1345
1346 /* --- @p_next@ --- *
1347  *
1348  * Arguments:   @peer_iter *i@ = pointer to an iterator
1349  *
1350  * Returns:     Next peer, or null if at the end.
1351  *
1352  * Use:         Returns the next peer.
1353  */
1354
1355 peer *p_next(peer_iter *i)
1356 {
1357   peer_byname *pn;
1358
1359   if ((pn = sym_next(&i->i)) == 0)
1360     return (0);
1361   return (pn->p);
1362 }
1363
1364 /*----- That's all, folks -------------------------------------------------*/