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 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.
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
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/>.
26 /*----- Header files ------------------------------------------------------*/
30 /*----- Static variables --------------------------------------------------*/
32 static sym_table byname;
33 static addrmap byaddr;
35 static unsigned nmobile;
37 /*----- Tunnel table ------------------------------------------------------*/
39 const tunnel_ops *tunnels[] = {
53 /*----- Main code ---------------------------------------------------------*/
55 /* --- @p_pingtype@ --- *
57 * Arguments: @unsigned msg@ = message type
59 * Returns: String to describe the message.
62 static const char *p_pingtype(unsigned msg)
64 switch (msg & MSG_TYPEMASK) {
67 return "transport-ping";
70 return "encrypted-ping";
76 /* --- @p_ponged@ --- *
78 * Arguments: @peer *p@ = peer packet arrived from
79 * @unsigned msg@ = message type
80 * @buf *b@ = buffer containing payload
84 * Use: Processes a ping response.
87 static void p_ponged(peer *p, unsigned msg, buf *b)
94 trace(T_PEER, "peer: received %s reply from %s",
95 p_pingtype(msg), p->spec.name);
96 trace_block(T_PACKET, "peer: ping contents", BBASE(b), BSZ(b));
99 if (buf_getu32(b, &id) ||
100 (magic = buf_get(b, sizeof(pg->magic))) == 0 ||
102 a_warn("PEER", "?PEER", p, "malformed-%s", p_pingtype(msg), A_END);
106 for (pg = p->pings; pg; pg = pg->next) {
112 "unexpected-%s", p_pingtype(msg),
113 "0x%08lx", (unsigned long)id,
118 if (memcmp(magic, pg->magic, sizeof(pg->magic)) != 0) {
119 a_warn("PEER", "?PEER", p, "corrupt-%s", p_pingtype(msg), A_END);
122 p_pingdone(pg, PING_OK);
125 /* --- @p_rxupdstats@ --- *
127 * Arguments: @peer *p@ = peer to update
128 * @size_t n@ = size of incoming packet
132 * Use: Updates the peer's incoming packet statistics.
135 static void p_rxupdstats(peer *p, size_t n)
137 p->st.t_last = time(0);
142 /* --- @p_encrypt@ --- *
144 * Arguments: @peer *p@ = peer to encrypt message to
145 * @int ty@ message type to send
146 * @buf *bin, *bout@ = input and output buffers
150 * Use: Convenience function for packet encryption. Forces
151 * renegotiation when necessary. Check for the output buffer
152 * being broken to find out whether the encryption was
156 static int p_encrypt(peer *p, int ty, buf *bin, buf *bout)
158 int err = ksl_encrypt(&p->ks, ty, bin, bout);
160 if (err == KSERR_REGEN) {
169 /* --- @p_decrypt@ --- *
171 * Arguments: @peer **pp@ = pointer to peer to decrypt message from
172 * @addr *a@ = address the packet arrived on
173 * @size_t n@ = size of original incoming packet
174 * @int ty@ = message type to expect
175 * @buf *bin, *bout@ = input and output buffers
177 * Returns: Zero on success; nonzero on error.
179 * Use: Convenience function for packet decryption. Reports errors
180 * and updates statistics appropriately.
182 * If @*pp@ is null on entry and there are mobile peers then we
183 * see if any of them can decrypt the packet. If so, we record
184 * @*a@ as the peer's new address and send a notification.
187 static int p_decrypt(peer **pp, addr *a, size_t n,
188 int ty, buf *bin, buf *bout)
191 peer_byaddr *pa, *qa;
192 int err = KSERR_DECRYPT;
195 /* --- If we have a match on the source address then try that first --- */
199 T( trace(T_PEER, "peer: decrypting packet from known peer `%s'",
201 if ((err = ksl_decrypt(&q->ks, ty, bin, bout)) != KSERR_DECRYPT ||
202 !(q->spec.f & PSF_MOBILE) || nmobile == 1) {
206 T( trace(T_PEER, "peer: failed to decrypt: try other mobile peers..."); )
208 T( trace(T_PEER, "peer: unknown source: trying mobile peers...") );
214 /* --- See whether any mobile peer is interested --- */
218 if (qq == q || !(qq->spec.f & PSF_MOBILE)) continue;
219 if ((err = ksl_decrypt(&qq->ks, ty, bin, bout)) == KSERR_DECRYPT) {
220 T( trace(T_PEER, "peer: peer `%s' failed to decrypt",
227 trace(T_PEER, "peer: peer `%s' reports success", p_name(qq));
229 trace(T_PEER, "peer: peer `%s' reports decryption error %d",
237 /* --- We've searched the mobile peers --- */
242 a_warn("PEER", "-", "unexpected-source", "?ADDR", a, A_END);
244 a_warn("PEER", "?PEER", p, "decrypt-failed",
245 "error-code", "%d", err, A_END);
251 /* --- We found one that accepted, so update the peer's address --- *
253 * If we had an initial guess of which peer this packet came from -- i.e.,
254 * @q@ is not null -- then swap the addresses over. This doesn't leave the
255 * evicted peer in an especially good state, but it ought to get sorted out
262 T( trace(T_PEER, "peer: updating address for `%s'", p_name(p)); )
263 pa = am_find(&byaddr, a, sizeof(peer_byaddr), &f); assert(!f);
264 am_remove(&byaddr, p->byaddr);
268 a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
270 T( trace(T_PEER, "peer: swapping addresses for `%s' and `%s'",
271 p_name(p), p_name(q)); )
272 pa = p->byaddr; qa = q->byaddr;
273 pa->p = q; q->byaddr = pa; q->spec.sa = p->spec.sa;
274 qa->p = p; p->byaddr = qa; p->spec.sa = *a;
275 a_notify("NEWADDR", "?PEER", p, "?ADDR", a, A_END);
276 a_notify("NEWADDR", "?PEER", q, "?ADDR", &q->spec.sa, A_END);
283 if (p) p->st.n_reject++;
284 a_warn("PEER", "?PEER", p, "decrypt-failed",
285 "error-code", "%d", err, A_END);
293 /* --- @p_read@ --- *
295 * Arguments: @int fd@ = file descriptor to read from
296 * @unsigned mode@ = what happened
297 * @void *v@ = an uninteresting pointer
301 * Use: Reads a packet from somewhere.
304 static void p_read(int fd, unsigned mode, void *v)
313 /* --- Read the data --- */
317 n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
319 a_warn("PEER", "-", "socket-read-error", "?ERRNO", A_END);
323 /* --- If the packet is a greeting, don't check peers --- */
325 if (n && buf_i[0] == (MSG_MISC | MISC_GREET)) {
327 trace(T_PEER, "peer: greeting received from INET %s %u",
328 inet_ntoa(a.sin.sin_addr),
329 (unsigned)ntohs(a.sin.sin_port));
330 trace_block(T_PACKET, "peer: greeting contents", buf_i, n);
332 buf_init(&b, buf_i, n);
334 if (c_check(&b) || BLEFT(&b)) {
335 a_warn("PEER", "-", "invalid-greeting", A_END);
339 "?B64", buf_i + 1, (size_t)(n - 1),
345 /* --- Find the appropriate peer --- *
347 * At this stage, don't worry too much about whether we actually found it.
350 p = p_findbyaddr(&a);
355 "peer: packet received from `%s' from address INET %s %d",
356 p_name(p), inet_ntoa(a.sin.sin_addr), ntohs(a.sin.sin_port));
358 trace(T_PEER, "peer: packet received from unknown address INET %s %d",
359 inet_ntoa(a.sin.sin_addr), ntohs(a.sin.sin_port));
361 trace_block(T_PACKET, "peer: packet contents", buf_i, n);
364 /* --- Pick the packet apart --- */
366 buf_init(&b, buf_i, n);
367 if ((ch = buf_getbyte(&b)) < 0) {
368 a_warn("PEER", "?PEER", p, "bad-packet", "no-type", A_END);
371 switch (ch & MSG_CATMASK) {
373 if (ch & MSG_TYPEMASK) {
377 "unknown-type", "0x%02x", ch,
379 if (p) p->st.n_reject++;
382 buf_init(&bb, buf_o, sizeof(buf_o));
383 if (p_decrypt(&p, &a, n, MSG_PACKET, &b, &bb))
387 p->st.sz_ipin += BSZ(&b);
388 p->t->ops->inject(p->t, &bb);
391 a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
397 kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
400 switch (ch & MSG_TYPEMASK) {
404 T( trace(T_PEER, "peer: received NOP packet"); )
409 buf_put(p_txstart(p, MSG_MISC | MISC_PONG), BCUR(&b), BLEFT(&b));
415 p_ponged(p, MISC_PONG, &b);
418 buf_init(&bb, buf_t, sizeof(buf_t));
419 if (p_decrypt(&p, &a, n, ch, &b, &bb))
423 p_encrypt(p, MSG_MISC | MISC_EPONG, &bb,
424 p_txstart(p, MSG_MISC | MISC_EPONG));
429 buf_init(&bb, buf_t, sizeof(buf_t));
430 if (p_decrypt(&p, &a, n, ch, &b, &bb))
434 p_ponged(p, MISC_EPONG, &bb);
440 if (p) p->st.n_reject++;
444 "unknown-category", "0x%02x", ch,
448 a_warn("PEER", "-", "unexpected-source", "?ADDR", &a, A_END);
453 /* --- @p_txstart@ --- *
455 * Arguments: @peer *p@ = pointer to peer block
456 * @unsigned msg@ = message type code
458 * Returns: A pointer to a buffer to write to.
460 * Use: Starts sending to a peer. Only one send can happen at a
464 buf *p_txstart(peer *p, unsigned msg)
466 buf_init(&p->b, buf_o, sizeof(buf_o));
467 buf_putbyte(&p->b, msg);
471 /* --- @p_txend@ --- *
473 * Arguments: @peer *p@ = pointer to peer block
477 * Use: Sends a packet to the peer.
480 static void p_setkatimer(peer *);
482 static int p_dotxend(peer *p)
485 a_warn("PEER", "?PEER", p, "packet-build-failed", A_END);
488 IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
489 BBASE(&p->b), BLEN(&p->b)); )
490 if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
491 0, &p->spec.sa.sa, p->spec.sasz) < 0) {
492 a_warn("PEER", "?PEER", p, "socket-write-error", "?ERRNO", A_END);
496 p->st.sz_out += BLEN(&p->b);
501 void p_txend(peer *p)
503 if (p_dotxend(p) && p->spec.t_ka) {
504 sel_rmtimer(&p->tka);
509 /* --- @p_pingwrite@ --- *
511 * Arguments: @ping *p@ = ping structure
512 * @buf *b@ = buffer to write in
516 * Use: Fills in a ping structure and writes the packet payload.
519 static void p_pingwrite(ping *p, buf *b)
521 static uint32 seq = 0;
524 GR_FILL(&rand_global, p->magic, sizeof(p->magic));
525 buf_putu32(b, p->id);
526 buf_put(b, p->magic, sizeof(p->magic));
529 /* --- @p_pingdone@ --- *
531 * Arguments: @ping *p@ = ping structure
532 * @int rc@ = return code to pass on
536 * Use: Disposes of a ping structure, maybe sending a notification.
539 void p_pingdone(ping *p, int rc)
541 if (p->prev) p->prev->next = p->next;
542 else p->p->pings = p->next;
543 if (p->next) p->next->prev = p->prev;
544 if (rc != PING_TIMEOUT) sel_rmtimer(&p->t);
545 T( trace(T_PEER, "peer: ping 0x%08lx done (rc = %d)",
546 (unsigned long)p->id, rc); )
547 if (rc >= 0) p->func(rc, p->arg);
550 /* --- @p_pingtimeout@ --- *
552 * Arguments: @struct timeval *now@ = the time now
553 * @void *pv@ = pointer to ping block
557 * Use: Called when a ping times out.
560 static void p_pingtimeout(struct timeval *now, void *pv)
564 T( trace(T_PEER, "peer: ping 0x%08lx timed out", (unsigned long)p->id); )
565 p_pingdone(p, PING_TIMEOUT);
568 /* --- @p_pingsend@ --- *
570 * Arguments: @peer *p@ = destination peer
571 * @ping *pg@ = structure to fill in
572 * @unsigned type@ = message type
573 * @unsigned long timeout@ = how long to wait before giving up
574 * @void (*func)(int, void *)@ = callback function
575 * @void *arg@ = argument for callback
577 * Returns: Zero if successful, nonzero if it failed.
579 * Use: Sends a ping to a peer. Call @func@ with a nonzero argument
580 * if we get an answer within the timeout, or zero if no answer.
583 int p_pingsend(peer *p, ping *pg, unsigned type,
584 unsigned long timeout,
585 void (*func)(int, void *), void *arg)
593 b = p_txstart(p, MSG_MISC | MISC_PING);
598 pg->msg = MISC_EPONG;
599 b = p_txstart(p, MSG_MISC | MISC_EPING);
600 buf_init(&bb, buf_t, sizeof(buf_t));
601 p_pingwrite(pg, &bb);
603 p_encrypt(p, MSG_MISC | MISC_EPING, &bb, b);
618 if (p->pings) p->pings->prev = pg;
620 gettimeofday(&tv, 0);
621 tv.tv_sec += timeout;
622 sel_addtimer(&sel, &pg->t, &tv, p_pingtimeout, pg);
623 T( trace(T_PEER, "peer: send %s 0x%08lx to %s",
624 p_pingtype(type), (unsigned long)pg->id, p->spec.name); )
628 /* --- @p_greet@ --- *
630 * Arguments: @peer *p@ = peer to send to
631 * @const void *c@ = pointer to challenge
632 * @size_t sz@ = size of challenge
636 * Use: Sends a greeting packet.
639 void p_greet(peer *p, const void *c, size_t sz)
641 buf *b = p_txstart(p, MSG_MISC | MISC_GREET);
648 * Arguments: @peer *p@ = pointer to peer block
649 * @buf *b@ = buffer containing incoming packet
653 * Use: Handles a packet which needs to be sent to a peer.
656 void p_tun(peer *p, buf *b)
658 buf *bb = p_txstart(p, MSG_PACKET);
661 p_encrypt(p, MSG_PACKET, b, bb);
662 if (BOK(bb) && BLEN(bb)) {
664 p->st.sz_ipout += BLEN(bb);
669 /* --- @p_keyreload@ --- *
675 * Use: Forces a check of the daemon's keyring files.
678 void p_keyreload(void)
681 FOREACH_PEER(p, { kx_newkeys(&p->kx); });
684 /* --- @p_interval@ --- *
690 * Use: Called periodically to do tidying.
693 void p_interval(void)
696 FOREACH_PEER(p, { ksl_prune(&p->ks); });
699 /* --- @p_stats@ --- *
701 * Arguments: @peer *p@ = pointer to a peer block
703 * Returns: A pointer to the peer's statistics.
706 stats *p_stats(peer *p) { return (&p->st); }
708 /* --- @p_ifname@ --- *
710 * Arguments: @peer *p@ = pointer to a peer block
712 * Returns: A pointer to the peer's interface name.
715 const char *p_ifname(peer *p) { return (p->ifname); }
717 /* --- @p_setifname@ --- *
719 * Arguments: @peer *p@ = pointer to a peer block
720 * @const char *name@ = pointer to the new name
724 * Use: Changes the name held for a peer's interface.
727 void p_setifname(peer *p, const char *name)
730 p->ifname = xstrdup(name);
731 if (p->spec.tops->setifname)
732 p->spec.tops->setifname(p->t, name);
735 /* --- @p_addr@ --- *
737 * Arguments: @peer *p@ = pointer to a peer block
739 * Returns: A pointer to the peer's address.
742 const addr *p_addr(peer *p) { return (&p->spec.sa); }
744 /* --- @p_init@ --- *
746 * Arguments: @struct in_addr addr@ = address to bind to
747 * @unsigned port@ = port number to listen to
751 * Use: Initializes the peer system; creates the socket.
754 void p_init(struct in_addr addr, unsigned port)
757 struct sockaddr_in sin;
760 /* --- Note on socket buffer sizes --- *
762 * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer
763 * sizes I pass to @setsockopt@. I'm not putting special-case code here
764 * for Linux: BSD (at least TCPv2) does what I tell it rather than second-
768 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
769 die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno));
771 sin.sin_family = AF_INET;
773 sin.sin_port = htons(port);
774 if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
775 die(EXIT_FAILURE, "bind failed: %s", strerror(errno));
776 if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
777 setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) {
778 die(EXIT_FAILURE, "failed to set socket buffer sizes: %s",
781 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
782 sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0);
784 T( trace(T_PEER, "peer: created socket"); )
790 /* --- @p_port@ --- *
794 * Returns: Port number used for socket.
797 unsigned p_port(void)
800 socklen_t sz = sizeof(addr);
802 if (getsockname(sock.fd, &a.sa, &sz))
803 die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
804 assert(a.sa.sa_family == AF_INET);
805 return (ntohs(a.sin.sin_port));
808 /* --- @p_keepalive@ --- *
810 * Arguments: @struct timeval *now@ = the current time
811 * @void *pv@ = peer to wake up
815 * Use: Sends a keepalive ping message to its peer.
818 static void p_keepalive(struct timeval *now, void *pv)
822 p_txstart(p, MSG_MISC | MISC_NOP); p_dotxend(p);
823 T( trace(T_PEER, "peer: sent keepalive to %s", p->spec.name); )
827 /* --- @p_setkatimer@ --- *
829 * Arguments: @peer *p@ = peer to set
833 * Use: Resets the keepalive timer thing.
836 static void p_setkatimer(peer *p)
842 gettimeofday(&tv, 0);
843 tv.tv_sec += p->spec.t_ka;
844 sel_addtimer(&sel, &p->tka, &tv, p_keepalive, p);
847 /* --- @p_create@ --- *
849 * Arguments: @peerspec *spec@ = information about this peer
851 * Returns: Pointer to the peer block, or null if it failed.
853 * Use: Creates a new named peer block. No peer is actually attached
857 peer *p_create(peerspec *spec)
859 peer *p = CREATE(peer);
860 const tunnel_ops *tops = spec->tops;
864 p->byname = sym_find(&byname, spec->name, -1, sizeof(peer_byname), &f);
866 p->byaddr = am_find(&byaddr, &spec->sa, sizeof(peer_byaddr), &f);
868 p->byname->p = p->byaddr->p = p;
870 T( trace(T_PEER, "peer: creating new peer `%s'", spec->name); )
872 p->spec.name = (/*unconst*/ char *)SYM_NAME(p->byname);
873 if (spec->tag) p->spec.tag = xstrdup(spec->tag);
874 if (spec->privtag) p->spec.privtag = xstrdup(spec->privtag);
878 memset(&p->st, 0, sizeof(stats));
879 p->st.t_start = time(0);
880 if (!(tops->flags & TUNF_PRIVOPEN))
882 else if ((fd = ps_tunfd(tops, &p->ifname)) < 0)
884 if ((p->t = tops->create(p, fd, &p->ifname)) == 0)
886 T( trace(T_TUNNEL, "peer: attached interface %s to peer `%s'",
887 p->ifname, p_name(p)); )
889 if (kx_init(&p->kx, p, &p->ks, p->spec.f & PSF_KXMASK))
894 "?ADDR", &p->spec.sa,
896 if (!(p->spec.f & KXF_CORK)) {
897 a_notify("KXSTART", "?PEER", p, A_END);
898 /* Couldn't tell anyone before */
900 if (p->spec.f & PSF_MOBILE) nmobile++;
904 if (spec->t_ka) sel_rmtimer(&p->tka);
906 p->t->ops->destroy(p->t);
908 if (fd >= 0) close(fd);
910 am_remove(&byaddr, p->byaddr);
911 if (p->spec.tag) xfree(p->spec.tag);
912 if (p->spec.privtag) xfree(p->spec.privtag);
914 sym_remove(&byname, p->byname);
920 /* --- @p_name@ --- *
922 * Arguments: @peer *p@ = pointer to a peer block
924 * Returns: A pointer to the peer's name.
927 const char *p_name(peer *p)
928 { if (p) return (p->spec.name); else return ("-"); }
932 * Arguments: @peer *p@ = pointer to a peer block
934 * Returns: A pointer to the peer's public key tag.
937 const char *p_tag(peer *p)
938 { return (p->spec.tag ? p->spec.tag : p->spec.name); }
940 /* --- @p_privtag@ --- *
942 * Arguments: @peer *p@ = pointer to a peer block
944 * Returns: A pointer to the peer's private key tag.
947 const char *p_privtag(peer *p)
948 { return (p->spec.privtag ? p->spec.privtag : tag_priv); }
950 /* --- @p_spec@ --- *
952 * Arguments: @peer *p@ = pointer to a peer block
954 * Returns: Pointer to the peer's specification
957 const peerspec *p_spec(peer *p) { return (&p->spec); }
959 /* --- @p_findbyaddr@ --- *
961 * Arguments: @const addr *a@ = address to look up
963 * Returns: Pointer to the peer block, or null if not found.
965 * Use: Finds a peer by address.
968 peer *p_findbyaddr(const addr *a)
972 if ((pa = am_find(&byaddr, a, 0, 0)) != 0) {
979 /* --- @p_find@ --- *
981 * Arguments: @const char *name@ = name to look up
983 * Returns: Pointer to the peer block, or null if not found.
985 * Use: Finds a peer by name.
988 peer *p_find(const char *name)
992 if ((pn = sym_find(&byname, name, -1, 0, 0)) != 0)
997 /* --- @p_destroy@ --- *
999 * Arguments: @peer *p@ = pointer to a peer
1003 * Use: Destroys a peer.
1006 void p_destroy(peer *p)
1010 T( trace(T_PEER, "peer: destroying peer `%s'", p->spec.name); )
1011 a_notify("KILL", "%s", p->spec.name, A_END);
1014 if (p->spec.f & PSF_MOBILE) nmobile--;
1015 if (p->ifname) xfree(p->ifname);
1016 if (p->spec.tag) xfree(p->spec.tag);
1017 if (p->spec.privtag) xfree(p->spec.privtag);
1018 p->t->ops->destroy(p->t);
1019 if (p->spec.t_ka) sel_rmtimer(&p->tka);
1020 for (pg = p->pings; pg; pg = ppg) {
1022 p_pingdone(pg, PING_PEERDIED);
1024 sym_remove(&byname, p->byname);
1025 am_remove(&byaddr, p->byaddr);
1029 /* --- @p_mkiter@ --- *
1031 * Arguments: @peer_iter *i@ = pointer to an iterator
1035 * Use: Initializes the iterator.
1038 void p_mkiter(peer_iter *i) { sym_mkiter(&i->i, &byname); }
1040 /* --- @p_next@ --- *
1042 * Arguments: @peer_iter *i@ = pointer to an iterator
1044 * Returns: Next peer, or null if at the end.
1046 * Use: Returns the next peer.
1049 peer *p_next(peer_iter *i)
1053 if ((pn = sym_next(&i->i)) == 0)
1058 /*----- That's all, folks -------------------------------------------------*/