3 * $Id: peer.c,v 1.9 2003/07/13 11:19:49 mdw Exp $
5 * Communication with the peer
7 * (c) 2001 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of Trivial IP Encryption (TrIPE).
14 * TrIPE is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * TrIPE is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with TrIPE; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.9 2003/07/13 11:19:49 mdw
33 * Incopatible protocol fix! Include message type code under MAC tag to prevent
34 * cut-and-paste from key-exchange messages to general packet transport.
36 * Revision 1.8 2003/05/16 12:09:03 mdw
37 * Allow binding to a chosen address.
39 * Revision 1.7 2003/04/15 14:12:05 mdw
40 * Insert a newline to improve readability.
42 * Revision 1.6 2001/06/19 22:07:59 mdw
43 * Use magic number for packet size.
45 * Revision 1.5 2001/03/03 11:15:19 mdw
46 * Set the socket send and receive buffers to maximum. At least this way,
47 * we won't drop large packets on the floor. If the administrator wants to
48 * prevent fragmentation of TrIPE messages, he can lower the MTU on the
49 * tunnel interface. Getting path-MTU stuff out of the kernel is too much
50 * system-specific hard work for this program.
52 * Revision 1.4 2001/02/16 21:40:24 mdw
53 * Change key exchange message interface. Maintain statistics.
55 * Revision 1.3 2001/02/04 17:10:58 mdw
56 * Make file descriptors be nonblocking and close-on-exec.
58 * Revision 1.2 2001/02/03 22:40:29 mdw
59 * Put timer information into the entropy pool when packets are received
60 * and on similar events. Reseed the generator on the interval timer.
62 * Revision 1.1 2001/02/03 20:26:37 mdw
67 /*----- Header files ------------------------------------------------------*/
71 /*----- Static variables --------------------------------------------------*/
73 static peer *peers = 0;
76 /*----- Main code ---------------------------------------------------------*/
80 * Arguments: @int fd@ = file descriptor to read from
81 * @unsigned mode@ = what happened
82 * @void *v@ = an uninteresting pointer
86 * Use: Reads a packet from somewhere.
89 static void p_read(int fd, unsigned mode, void *v)
98 /* --- Read the data --- */
102 n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
104 a_warn("error reading socket: %s", strerror(errno));
108 /* --- Find the appropriate peer --- */
110 assert(a.sa.sa_family == AF_INET);
111 for (p = peers; p; p = p->next) {
112 if (p->peer.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr &&
113 p->peer.sin.sin_port == a.sin.sin_port)
116 a_warn("packet from unexpected peer: %s:%u",
117 inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port));
121 T( trace(T_PEER, "peer: packet received from `%s'", p->name);
122 trace_block(T_PACKET, "peer: packet contents", buf_i, n); )
124 /* --- Pick the packet apart --- */
126 p->st.t_last = time(0);
129 buf_init(&b, buf_i, n);
130 if ((ch = buf_getbyte(&b)) < 0) {
131 a_warn("bad packet from `%s': no type byte", p->name);
134 switch (ch & MSG_CATMASK) {
136 if (ch & MSG_TYPEMASK) {
137 a_warn("unknown packet type from `%s'", p->name);
141 buf_init(&bb, buf_o, sizeof(buf_o));
142 if (ksl_decrypt(&p->ks, MSG_PACKET, &b, &bb)) {
144 a_warn("couldn't decrypt inbound packet from `%s'", p->name);
149 p->st.sz_ipin += BSZ(&b);
150 tun_inject(&p->t, &bb);
153 a_warn("packet build failed");
157 kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
161 a_warn("bad packet from `%s': unknown packet type", p->name);
166 /* --- @p_txstart@ --- *
168 * Arguments: @peer *p@ = pointer to peer block
169 * @unsigned msg@ = message type code
171 * Returns: A pointer to a buffer to write to.
173 * Use: Starts sending to a peer. Only one send can happen at a
177 buf *p_txstart(peer *p, unsigned msg)
179 buf_init(&p->b, buf_o, sizeof(buf_o));
180 buf_putbyte(&p->b, msg);
184 /* --- @p_txend@ --- *
186 * Arguments: @peer *p@ = pointer to peer block
190 * Use: Sends a packet to the peer.
193 void p_txend(peer *p)
196 a_warn("packet build failed");
199 IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
200 BBASE(&p->b), BLEN(&p->b)); )
201 if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
202 0, &p->peer.sa, p->sasz) < 0)
203 a_warn("packet send to `%s' failed: %s", p->name, strerror(errno));
206 p->st.sz_out += BLEN(&p->b);
212 * Arguments: @peer *p@ = pointer to peer block
213 * @buf *b@ = buffer containing incoming packet
217 * Use: Handles a packet which needs to be sent to a peer.
220 void p_tun(peer *p, buf *b)
222 buf *bb = p_txstart(p, MSG_PACKET);
225 if (ksl_encrypt(&p->ks, MSG_PACKET, b, bb))
227 if (BOK(bb) && BLEN(bb)) {
229 p->st.sz_ipout += BLEN(bb);
234 /* --- @p_interval@ --- *
240 * Use: Called periodically to do tidying.
243 void p_interval(void)
248 reload = km_interval();
249 for (p = peers; p; p = pp) {
257 /* --- @p_stats@ --- *
259 * Arguments: @peer *p@ = pointer to a peer block
261 * Returns: A pointer to the peer's statistics.
264 stats *p_stats(peer *p) { return (&p->st); }
266 /* --- @p_ifname@ --- *
268 * Arguments: @peer *p@ = pointer to a peer block
270 * Returns: A pointer to the peer's interface name.
273 const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); }
275 /* --- @p_addr@ --- *
277 * Arguments: @peer *p@ = pointer to a peer block
279 * Returns: A pointer to the peer's address.
282 const addr *p_addr(peer *p) { return (&p->peer); }
284 /* --- @p_init@ --- *
286 * Arguments: @struct in_addr addr@ = address to bind to
287 * @unsigned port@ = port number to listen to
291 * Use: Initializes the peer system; creates the socket.
294 void p_init(struct in_addr addr, unsigned port)
297 struct sockaddr_in sin;
300 /* --- Note on socket buffer sizes --- *
302 * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer
303 * sizes I pass to @setsockopt@. I'm not putting special-case code here
304 * for Linux: BSD (at least TCPv2) does what I tell it rather than second-
308 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
309 die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno));
311 sin.sin_family = AF_INET;
313 sin.sin_port = htons(port);
314 if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
315 die(EXIT_FAILURE, "bind failed: %s", strerror(errno));
316 if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
317 setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) {
318 die(EXIT_FAILURE, "failed to set socket buffer sizes: %s",
321 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
322 sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0);
324 T( trace(T_PEER, "peer: created socket"); )
327 /* --- @p_port@ --- *
331 * Returns: Port number used for socket.
334 unsigned p_port(void)
337 size_t sz = sizeof(addr);
339 if (getsockname(sock.fd, &a.sa, &sz))
340 die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
341 assert(a.sa.sa_family == AF_INET);
342 return (ntohs(a.sin.sin_port));
345 /* --- @p_create@ --- *
347 * Arguments: @const char *name@ = name for this peer
348 * @struct sockaddr *sa@ = socket address of peer
349 * @size_t sz@ = size of socket address
351 * Returns: Pointer to the peer block, or null if it failed.
353 * Use: Creates a new named peer block. No peer is actually attached
357 peer *p_create(const char *name, struct sockaddr *sa, size_t sz)
359 peer *p = CREATE(peer);
360 T( trace(T_PEER, "peer: creating new peer `%s'", name); )
361 p->name = xstrdup(name);
364 memcpy(&p->peer.sa, sa, sz);
366 memset(&p->st, 0, sizeof(stats));
367 p->st.t_start = time(0);
368 if (kx_init(&p->kx, p, &p->ks))
370 if (tun_create(&p->t, p))
386 /* --- @p_name@ --- *
388 * Arguments: @peer *p@ = pointer to a peer block
390 * Returns: A pointer to the peer's name.
393 const char *p_name(peer *p) { return (p->name); }
395 /* --- @p_find@ --- *
397 * Arguments: @const char *name@ = name to look up
399 * Returns: Pointer to the peer block, or null if not found.
401 * Use: Finds a peer by name.
404 peer *p_find(const char *name)
407 for (p = peers; p; p = p->next) {
408 if (strcmp(name, p->name) == 0)
414 /* --- @p_destroy@ --- *
416 * Arguments: @peer *p@ = pointer to a peer
420 * Use: Destroys a peer.
423 void p_destroy(peer *p)
425 T( trace(T_PEER, "peer: destroying peer `%s'", p->name); )
431 p->next->prev = p->prev;
433 p->prev->next = p->next;
439 /* --- @p_first@, @p_next@ --- *
441 * Arguments: @peer *p@ = a peer block
443 * Returns: @peer_first@ returns the first peer in some ordering;
444 * @peer_next@ returns the peer following a given one in the
445 * same ordering. Null is returned for the end of the list.
448 peer *p_first(void) { return (peers); }
449 peer *p_next(peer *p) { return (p->next); }
451 /*----- That's all, folks -------------------------------------------------*/