3 * Communication with the peer
5 * (c) 2001 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Trivial IP Encryption (TrIPE).
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.
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.
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.
27 /*----- Header files ------------------------------------------------------*/
31 /*----- Static variables --------------------------------------------------*/
33 static sym_table byname;
34 static addrmap byaddr;
36 static unsigned nmobile;
38 /*----- Tunnel table ------------------------------------------------------*/
40 const tunnel_ops *tunnels[] = {
54 /*----- Main code ---------------------------------------------------------*/
56 /* --- @p_pingtype@ --- *
58 * Arguments: @unsigned msg@ = message type
60 * Returns: String to describe the message.
63 static const char *p_pingtype(unsigned msg)
65 switch (msg & MSG_TYPEMASK) {
68 return "transport-ping";
71 return "encrypted-ping";
77 /* --- @p_ponged@ --- *
79 * Arguments: @peer *p@ = peer packet arrived from
80 * @unsigned msg@ = message type
81 * @buf *b@ = buffer containing payload
85 * Use: Processes a ping response.
88 static void p_ponged(peer *p, unsigned msg, buf *b)
95 trace(T_PEER, "peer: received %s reply from %s",
96 p_pingtype(msg), p->spec.name);
97 trace_block(T_PACKET, "peer: ping contents", BBASE(b), BSZ(b));
100 if (buf_getu32(b, &id) ||
101 (magic = buf_get(b, sizeof(pg->magic))) == 0 ||
103 a_warn("PEER", "?PEER", p, "malformed-%s", p_pingtype(msg), A_END);
107 for (pg = p->pings; pg; pg = pg->next) {
113 "unexpected-%s", p_pingtype(msg),
114 "0x%08lx", (unsigned long)id,
119 if (memcmp(magic, pg->magic, sizeof(pg->magic)) != 0) {
120 a_warn("PEER", "?PEER", p, "corrupt-%s", p_pingtype(msg), A_END);
123 p_pingdone(pg, PING_OK);
126 /* --- @p_rxupdstats@ --- *
128 * Arguments: @peer *p@ = peer to update
129 * @size_t n@ = size of incoming packet
133 * Use: Updates the peer's incoming packet statistics.
136 static void p_rxupdstats(peer *p, size_t n)
138 p->st.t_last = time(0);
143 /* --- @p_encrypt@ --- *
145 * Arguments: @peer *p@ = peer to encrypt message to
146 * @int ty@ message type to send
147 * @buf *bin, *bout@ = input and output buffers
151 * Use: Convenience function for packet encryption. Forces
152 * renegotiation when necessary. Check for the output buffer
153 * being broken to find out whether the encryption was
157 static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
159 int err = ksl_encrypt(&p->ks, ty, bin, bout);
161 if (err == KSERR_REGEN) {
170 /* --- @p_decrypt@ --- *
172 * Arguments: @peer **pp@ = pointer to peer to decrypt message from
173 * @addr *a@ = address the packet arrived on
174 * @size_t n@ = size of original incoming packet
175 * @int ty@ = message type to expect
176 * @buf *bin, *bout@ = input and output buffers
178 * Returns: Zero on success; nonzero on error.
180 * Use: Convenience function for packet decryption. Reports errors
181 * and updates statistics appropriately.
183 * If @*pp@ is null on entry and there are mobile peers then we
184 * see if any of them can decrypt the packet. If so, we record
185 * @*a@ as the peer's new address and send a notification.
188 static int p_decrypt(peer **pp, addr *a, size_t n,
189 int ty, buf *bin, buf *bout)
192 peer_byaddr *pa, *qa;
193 int err = KSERR_DECRYPT;
196 /* --- If we have a match on the source address then try that first --- */
200 T( trace(T_PEER, "peer: decrypting packet from known peer `%s'",
202 if ((err = ksl_decrypt(&q->ks, ty, bin, bout)) != KSERR_DECRYPT ||
203 !(q->spec.f & PSF_MOBILE) || nmobile == 1) {
207 T( trace(T_PEER, "peer: failed to decrypt: try other mobile peers...",
210 T( trace(T_PEER, "peer: unknown source: trying mobile peers..."); )
216 /* --- See whether any mobile peer is interested --- */
220 if (qq == q || !(qq->spec.f & PSF_MOBILE)) continue;
221 if ((err = ksl_decrypt(&qq->ks, ty, bin, bout)) == KSERR_DECRYPT) {
222 T( trace(T_PEER, "peer: peer `%s' failed to decrypt",
229 trace(T_PEER, "peer: peer `%s' reports success", p_name(qq));
231 trace(T_PEER, "peer: peer `%s' reports decryption error %d",
239 /* --- We've searched the mobile peers --- */
244 a_warn("PEER", "-", "unexpected-source", "?ADDR", a, A_END);
246 a_warn("PEER", "?PEER", p, "decrypt-failed",
247 "error-code", "%d", err, A_END);
253 /* --- We found one that accepted, so update the peer's address --- *
255 * If we had an initial guess of which peer this packet came from -- i.e.,
256 * @q@ is not null -- then swap the addresses over. This doesn't leave the
257 * evicted peer in an especially good state, but it ought to get sorted out
264 T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
265 pa = am_find(&byaddr, a, sizeof(peer_byaddr), &f); assert(!f);
266 am_remove(&byaddr, p->byaddr);
270 a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
272 T( trace(T_PEER, "peer: swapping addresses for `%s' and `%s'",
273 p_name(p), p_name(q)); )
274 pa = p->byaddr; qa = q->byaddr;
275 pa->p = q; q->byaddr = pa; q->spec.sa = p->spec.sa;
276 qa->p = p; p->byaddr = qa; p->spec.sa = *a;
277 a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
278 a_notify("NEWADDR", "?PEER", q, "?ADDR", &q->spec.sa, A_END);
285 if (p) p->st.n_reject++;
286 a_warn("PEER", "?PEER", p, "decrypt-failed",
287 "error-code", "%d", err, A_END);
295 /* --- @p_read@ --- *
297 * Arguments: @int fd@ = file descriptor to read from
298 * @unsigned mode@ = what happened
299 * @void *v@ = an uninteresting pointer
303 * Use: Reads a packet from somewhere.
306 static void p_read(int fd, unsigned mode, void *v)
315 /* --- Read the data --- */
319 n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
321 a_warn("PEER", "-", "socket-read-error", "?ERRNO", A_END);
325 /* --- If the packet is a greeting, don't check peers --- */
327 if (n && buf_i[0] == (MSG_MISC | MISC_GREET)) {
329 trace(T_PEER, "peer: greeting received from INET %s %u",
330 inet_ntoa(a.sin.sin_addr),
331 (unsigned)ntohs(a.sin.sin_port));
332 trace_block(T_PACKET, "peer: greeting contents", buf_i, n);
334 buf_init(&b, buf_i, n);
336 if (c_check(&b) || BLEFT(&b)) {
337 a_warn("PEER", "-", "invalid-greeting", A_END);
341 "?B64", buf_i + 1, (size_t)(n - 1),
347 /* --- Find the appropriate peer --- *
349 * At this stage, don't worry too much about whether we actually found it.
352 p = p_findbyaddr(&a);
357 "peer: packet received from `%s' from address INET %s %d",
358 p_name(p), inet_ntoa(a.sin.sin_addr), ntohs(a.sin.sin_port));
360 trace(T_PEER, "peer: packet received from unknown address INET %s %d",
361 inet_ntoa(a.sin.sin_addr), ntohs(a.sin.sin_port));
363 trace_block(T_PACKET, "peer: packet contents", buf_i, n);
366 /* --- Pick the packet apart --- */
368 buf_init(&b, buf_i, n);
369 if ((ch = buf_getbyte(&b)) < 0) {
370 a_warn("PEER", "?PEER", p, "bad-packet", "no-type", A_END);
373 switch (ch & MSG_CATMASK) {
375 if (ch & MSG_TYPEMASK) {
379 "unknown-type", "0x%02x", ch,
381 if (p) p->st.n_reject++;
384 buf_init(&bb, buf_o, sizeof(buf_o));
385 if (p_decrypt(&p, &a, n, MSG_PACKET, &b, &bb))
389 p->st.sz_ipin += BSZ(&b);
390 p->t->ops->inject(p->t, &bb);
393 a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
399 kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
402 switch (ch & MSG_TYPEMASK) {
406 T( trace(T_PEER, "peer: received NOP packet"); )
411 buf_put(p_txstart(p, MSG_MISC | MISC_PONG), BCUR(&b), BLEFT(&b));
417 p_ponged(p, MISC_PONG, &b);
420 buf_init(&bb, buf_t, sizeof(buf_t));
421 if (p_decrypt(&p, &a, n, ch, &b, &bb))
425 p_encrypt(p, MSG_MISC | MISC_EPONG, &bb,
426 p_txstart(p, MSG_MISC | MISC_EPONG));
431 buf_init(&bb, buf_t, sizeof(buf_t));
432 if (p_decrypt(&p, &a, n, ch, &b, &bb))
436 p_ponged(p, MISC_EPONG, &bb);
442 if (p) p->st.n_reject++;
446 "unknown-category", "0x%02x", ch,
450 a_warn("PEER", "-", "unexpected-source", "?ADDR", &a, A_END);
455 /* --- @p_txstart@ --- *
457 * Arguments: @peer *p@ = pointer to peer block
458 * @unsigned msg@ = message type code
460 * Returns: A pointer to a buffer to write to.
462 * Use: Starts sending to a peer. Only one send can happen at a
466 buf *p_txstart(peer *p, unsigned msg)
468 buf_init(&p->b, buf_o, sizeof(buf_o));
469 buf_putbyte(&p->b, msg);
473 /* --- @p_txend@ --- *
475 * Arguments: @peer *p@ = pointer to peer block
479 * Use: Sends a packet to the peer.
482 static void p_setkatimer(peer *);
484 static int p_dotxend(peer *p)
487 a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
490 IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
491 BBASE(&p->b), BLEN(&p->b)); )
492 if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
493 0, &p->spec.sa.sa, p->spec.sasz) < 0) {
494 a_warn("PEER", "?PEER", p, "socket-write-error", "?ERRNO", A_END);
498 p->st.sz_out += BLEN(&p->b);
503 void p_txend(peer *p)
505 if (p_dotxend(p) && p->spec.t_ka) {
506 sel_rmtimer(&p->tka);
511 /* --- @p_pingwrite@ --- *
513 * Arguments: @ping *p@ = ping structure
514 * @buf *b@ = buffer to write in
518 * Use: Fills in a ping structure and writes the packet payload.
521 static void p_pingwrite(ping *p, buf *b)
523 static uint32 seq = 0;
526 GR_FILL(&rand_global, p->magic, sizeof(p->magic));
527 buf_putu32(b, p->id);
528 buf_put(b, p->magic, sizeof(p->magic));
531 /* --- @p_pingdone@ --- *
533 * Arguments: @ping *p@ = ping structure
534 * @int rc@ = return code to pass on
538 * Use: Disposes of a ping structure, maybe sending a notification.
541 void p_pingdone(ping *p, int rc)
543 if (p->prev) p->prev->next = p->next;
544 else p->p->pings = p->next;
545 if (p->next) p->next->prev = p->prev;
546 if (rc != PING_TIMEOUT) sel_rmtimer(&p->t);
547 T( trace(T_PEER, "peer: ping 0x%08lx done (rc = %d)",
548 (unsigned long)p->id, rc); )
549 if (rc >= 0) p->func(rc, p->arg);
552 /* --- @p_pingtimeout@ --- *
554 * Arguments: @struct timeval *now@ = the time now
555 * @void *pv@ = pointer to ping block
559 * Use: Called when a ping times out.
562 static void p_pingtimeout(struct timeval *now, void *pv)
566 T( trace(T_PEER, "peer: ping 0x%08lx timed out", (unsigned long)p->id); )
567 p_pingdone(p, PING_TIMEOUT);
570 /* --- @p_pingsend@ --- *
572 * Arguments: @peer *p@ = destination peer
573 * @ping *pg@ = structure to fill in
574 * @unsigned type@ = message type
575 * @unsigned long timeout@ = how long to wait before giving up
576 * @void (*func)(int, void *)@ = callback function
577 * @void *arg@ = argument for callback
579 * Returns: Zero if successful, nonzero if it failed.
581 * Use: Sends a ping to a peer. Call @func@ with a nonzero argument
582 * if we get an answer within the timeout, or zero if no answer.
585 int p_pingsend(peer *p, ping *pg, unsigned type,
586 unsigned long timeout,
587 void (*func)(int, void *), void *arg)
595 b = p_txstart(p, MSG_MISC | MISC_PING);
600 pg->msg = MISC_EPONG;
601 b = p_txstart(p, MSG_MISC | MISC_EPING);
602 buf_init(&bb, buf_t, sizeof(buf_t));
603 p_pingwrite(pg, &bb);
605 p_encrypt(p, MSG_MISC | MISC_EPING, &bb, b);
620 if (p->pings) p->pings->prev = pg;
622 gettimeofday(&tv, 0);
623 tv.tv_sec += timeout;
624 sel_addtimer(&sel, &pg->t, &tv, p_pingtimeout, pg);
625 T( trace(T_PEER, "peer: send %s 0x%08lx to %s",
626 p_pingtype(type), (unsigned long)pg->id, p->spec.name); )
630 /* --- @p_greet@ --- *
632 * Arguments: @peer *p@ = peer to send to
633 * @const void *c@ = pointer to challenge
634 * @size_t sz@ = size of challenge
638 * Use: Sends a greeting packet.
641 void p_greet(peer *p, const void *c, size_t sz)
643 buf *b = p_txstart(p, MSG_MISC | MISC_GREET);
650 * Arguments: @peer *p@ = pointer to peer block
651 * @buf *b@ = buffer containing incoming packet
655 * Use: Handles a packet which needs to be sent to a peer.
658 void p_tun(peer *p, buf *b)
660 buf *bb = p_txstart(p, MSG_PACKET);
663 p_encrypt(p, MSG_PACKET, b, bb);
664 if (BOK(bb) && BLEN(bb)) {
666 p->st.sz_ipout += BLEN(bb);
671 /* --- @p_keyreload@ --- *
677 * Use: Forces a check of the daemon's keyring files.
680 void p_keyreload(void)
683 FOREACH_PEER(p, { kx_newkeys(&p->kx); });
686 /* --- @p_interval@ --- *
692 * Use: Called periodically to do tidying.
695 void p_interval(void)
698 FOREACH_PEER(p, { ksl_prune(&p->ks); });
701 /* --- @p_stats@ --- *
703 * Arguments: @peer *p@ = pointer to a peer block
705 * Returns: A pointer to the peer's statistics.
708 stats *p_stats(peer *p) { return (&p->st); }
710 /* --- @p_ifname@ --- *
712 * Arguments: @peer *p@ = pointer to a peer block
714 * Returns: A pointer to the peer's interface name.
717 const char *p_ifname(peer *p) { return (p->ifname); }
719 /* --- @p_setifname@ --- *
721 * Arguments: @peer *p@ = pointer to a peer block
722 * @const char *name@ = pointer to the new name
726 * Use: Changes the name held for a peer's interface.
729 void p_setifname(peer *p, const char *name)
732 p->ifname = xstrdup(name);
733 if (p->spec.tops->setifname)
734 p->spec.tops->setifname(p->t, name);
737 /* --- @p_addr@ --- *
739 * Arguments: @peer *p@ = pointer to a peer block
741 * Returns: A pointer to the peer's address.
744 const addr *p_addr(peer *p) { return (&p->spec.sa); }
746 /* --- @p_init@ --- *
748 * Arguments: @struct in_addr addr@ = address to bind to
749 * @unsigned port@ = port number to listen to
753 * Use: Initializes the peer system; creates the socket.
756 void p_init(struct in_addr addr, unsigned port)
759 struct sockaddr_in sin;
762 /* --- Note on socket buffer sizes --- *
764 * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer
765 * sizes I pass to @setsockopt@. I'm not putting special-case code here
766 * for Linux: BSD (at least TCPv2) does what I tell it rather than second-
770 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
771 die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno));
773 sin.sin_family = AF_INET;
775 sin.sin_port = htons(port);
776 if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
777 die(EXIT_FAILURE, "bind failed: %s", strerror(errno));
778 if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
779 setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) {
780 die(EXIT_FAILURE, "failed to set socket buffer sizes: %s",
783 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
784 sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0);
786 T( trace(T_PEER, "peer: created socket"); )
792 /* --- @p_port@ --- *
796 * Returns: Port number used for socket.
799 unsigned p_port(void)
802 size_t sz = sizeof(addr);
804 if (getsockname(sock.fd, &a.sa, &sz))
805 die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
806 assert(a.sa.sa_family == AF_INET);
807 return (ntohs(a.sin.sin_port));
810 /* --- @p_keepalive@ --- *
812 * Arguments: @struct timeval *now@ = the current time
813 * @void *pv@ = peer to wake up
817 * Use: Sends a keepalive ping message to its peer.
820 static void p_keepalive(struct timeval *now, void *pv)
823 p_txstart(p, MSG_MISC | MISC_NOP); p_dotxend(p);
824 T( trace(T_PEER, "peer: sent keepalive to %s", p->spec.name); )
828 /* --- @p_setkatimer@ --- *
830 * Arguments: @peer *p@ = peer to set
834 * Use: Resets the keepalive timer thing.
837 static void p_setkatimer(peer *p)
843 gettimeofday(&tv, 0);
844 tv.tv_sec += p->spec.t_ka;
845 sel_addtimer(&sel, &p->tka, &tv, p_keepalive, p);
848 /* --- @p_create@ --- *
850 * Arguments: @peerspec *spec@ = information about this peer
852 * Returns: Pointer to the peer block, or null if it failed.
854 * Use: Creates a new named peer block. No peer is actually attached
858 peer *p_create(peerspec *spec)
860 peer *p = CREATE(peer);
861 const tunnel_ops *tops = spec->tops;
865 p->byname = sym_find(&byname, spec->name, -1, sizeof(peer_byname), &f);
867 p->byaddr = am_find(&byaddr, &spec->sa, sizeof(peer_byaddr), &f);
869 p->byname->p = p->byaddr->p = p;
871 T( trace(T_PEER, "peer: creating new peer `%s'", spec->name); )
873 p->spec.name = (/*unconst*/ char *)SYM_NAME(p->byname);
875 p->spec.tag = xstrdup(spec->tag);
879 memset(&p->st, 0, sizeof(stats));
880 p->st.t_start = time(0);
881 if (!(tops->flags & TUNF_PRIVOPEN))
883 else if ((fd = ps_tunfd(tops, &p->ifname)) < 0)
885 if ((p->t = tops->create(p, fd, &p->ifname)) == 0)
887 T( trace(T_TUNNEL, "peer: attached interface %s to peer `%s'",
888 p->ifname, p_name(p)); )
890 if (kx_init(&p->kx, p, &p->ks, p->spec.f & PSF_KXMASK))
895 "?ADDR", &p->spec.sa,
897 if (!(p->spec.f & KXF_CORK)) {
898 a_notify("KXSTART", "?PEER", p, A_END);
899 /* Couldn't tell anyone before */
901 if (p->spec.f & PSF_MOBILE) nmobile++;
906 sel_rmtimer(&p->tka);
908 p->t->ops->destroy(p->t);
910 if (fd >= 0) close(fd);
912 am_remove(&byaddr, p->byaddr);
913 if (p->spec.tag) xfree(p->spec.tag);
915 sym_remove(&byname, p->byname);
921 /* --- @p_name@ --- *
923 * Arguments: @peer *p@ = pointer to a peer block
925 * Returns: A pointer to the peer's name.
928 const char *p_name(peer *p)
929 { if (p) return (p->spec.name); else return ("-"); }
933 * Arguments: @peer *p@ = pointer to a peer block
935 * Returns: A pointer to the peer's public key tag.
938 const char *p_tag(peer *p)
939 { return (p->spec.tag ? p->spec.tag : p->spec.name); }
941 /* --- @p_spec@ --- *
943 * Arguments: @peer *p@ = pointer to a peer block
945 * Returns: Pointer to the peer's specification
948 const peerspec *p_spec(peer *p) { return (&p->spec); }
950 /* --- @p_findbyaddr@ --- *
952 * Arguments: @const addr *a@ = address to look up
954 * Returns: Pointer to the peer block, or null if not found.
956 * Use: Finds a peer by address.
959 peer *p_findbyaddr(const addr *a)
963 if ((pa = am_find(&byaddr, a, 0, 0)) != 0) {
970 /* --- @p_find@ --- *
972 * Arguments: @const char *name@ = name to look up
974 * Returns: Pointer to the peer block, or null if not found.
976 * Use: Finds a peer by name.
979 peer *p_find(const char *name)
983 if ((pn = sym_find(&byname, name, -1, 0, 0)) != 0)
988 /* --- @p_destroy@ --- *
990 * Arguments: @peer *p@ = pointer to a peer
994 * Use: Destroys a peer.
997 void p_destroy(peer *p)
1001 T( trace(T_PEER, "peer: destroying peer `%s'", p->spec.name); )
1002 a_notify("KILL", "%s", p->spec.name, A_END);
1005 if (p->spec.f & PSF_MOBILE)
1011 p->t->ops->destroy(p->t);
1013 sel_rmtimer(&p->tka);
1014 for (pg = p->pings; pg; pg = ppg) {
1016 p_pingdone(pg, PING_PEERDIED);
1018 sym_remove(&byname, p->byname);
1019 am_remove(&byaddr, p->byaddr);
1023 /* --- @p_mkiter@ --- *
1025 * Arguments: @peer_iter *i@ = pointer to an iterator
1029 * Use: Initializes the iterator.
1032 void p_mkiter(peer_iter *i) { sym_mkiter(&i->i, &byname); }
1034 /* --- @p_next@ --- *
1036 * Arguments: @peer_iter *i@ = pointer to an iterator
1038 * Returns: Next peer, or null if at the end.
1040 * Use: Returns the next peer.
1043 peer *p_next(peer_iter *i)
1047 if ((pn = sym_next(&i->i)) == 0)
1052 /*----- That's all, folks -------------------------------------------------*/