3 * $Id: peer.c,v 1.8 2003/05/16 12:09:03 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 1.8 2003/05/16 12:09:03 mdw
33 * Allow binding to a chosen address.
35 * Revision 1.7 2003/04/15 14:12:05 mdw
36 * Insert a newline to improve readability.
38 * Revision 1.6 2001/06/19 22:07:59 mdw
39 * Use magic number for packet size.
41 * Revision 1.5 2001/03/03 11:15:19 mdw
42 * Set the socket send and receive buffers to maximum. At least this way,
43 * we won't drop large packets on the floor. If the administrator wants to
44 * prevent fragmentation of TrIPE messages, he can lower the MTU on the
45 * tunnel interface. Getting path-MTU stuff out of the kernel is too much
46 * system-specific hard work for this program.
48 * Revision 1.4 2001/02/16 21:40:24 mdw
49 * Change key exchange message interface. Maintain statistics.
51 * Revision 1.3 2001/02/04 17:10:58 mdw
52 * Make file descriptors be nonblocking and close-on-exec.
54 * Revision 1.2 2001/02/03 22:40:29 mdw
55 * Put timer information into the entropy pool when packets are received
56 * and on similar events. Reseed the generator on the interval timer.
58 * Revision 1.1 2001/02/03 20:26:37 mdw
63 /*----- Header files ------------------------------------------------------*/
67 /*----- Static variables --------------------------------------------------*/
69 static peer *peers = 0;
72 /*----- Main code ---------------------------------------------------------*/
76 * Arguments: @int fd@ = file descriptor to read from
77 * @unsigned mode@ = what happened
78 * @void *v@ = an uninteresting pointer
82 * Use: Reads a packet from somewhere.
85 static void p_read(int fd, unsigned mode, void *v)
94 /* --- Read the data --- */
98 n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
100 a_warn("error reading socket: %s", strerror(errno));
104 /* --- Find the appropriate peer --- */
106 assert(a.sa.sa_family == AF_INET);
107 for (p = peers; p; p = p->next) {
108 if (p->peer.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr &&
109 p->peer.sin.sin_port == a.sin.sin_port)
112 a_warn("packet from unexpected peer: %s:%u",
113 inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port));
117 T( trace(T_PEER, "peer: packet received from `%s'", p->name);
118 trace_block(T_PACKET, "peer: packet contents", buf_i, n); )
120 /* --- Pick the packet apart --- */
122 p->st.t_last = time(0);
125 buf_init(&b, buf_i, n);
126 if ((ch = buf_getbyte(&b)) < 0) {
127 a_warn("bad packet from `%s': no type byte", p->name);
130 switch (ch & MSG_CATMASK) {
132 if (ch & MSG_TYPEMASK) {
133 a_warn("unknown packet type from `%s'", p->name);
137 buf_init(&bb, buf_o, sizeof(buf_o));
138 if (ksl_decrypt(&p->ks, &b, &bb)) {
140 a_warn("couldn't decrypt inbound packet from `%s'", p->name);
145 p->st.sz_ipin += BSZ(&b);
146 tun_inject(&p->t, &bb);
149 a_warn("packet build failed");
153 kx_message(&p->kx, ch & MSG_TYPEMASK, &b);
157 a_warn("bad packet from `%s': unknown packet type", p->name);
162 /* --- @p_txstart@ --- *
164 * Arguments: @peer *p@ = pointer to peer block
165 * @unsigned msg@ = message type code
167 * Returns: A pointer to a buffer to write to.
169 * Use: Starts sending to a peer. Only one send can happen at a
173 buf *p_txstart(peer *p, unsigned msg)
175 buf_init(&p->b, buf_o, sizeof(buf_o));
176 buf_putbyte(&p->b, msg);
180 /* --- @p_txend@ --- *
182 * Arguments: @peer *p@ = pointer to peer block
186 * Use: Sends a packet to the peer.
189 void p_txend(peer *p)
192 a_warn("packet build failed");
195 IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
196 BBASE(&p->b), BLEN(&p->b)); )
197 if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
198 0, &p->peer.sa, p->sasz) < 0)
199 a_warn("packet send to `%s' failed: %s", p->name, strerror(errno));
202 p->st.sz_out += BLEN(&p->b);
208 * Arguments: @peer *p@ = pointer to peer block
209 * @buf *b@ = buffer containing incoming packet
213 * Use: Handles a packet which needs to be sent to a peer.
216 void p_tun(peer *p, buf *b)
218 buf *bb = p_txstart(p, MSG_PACKET);
221 if (ksl_encrypt(&p->ks, b, bb))
223 if (BOK(bb) && BLEN(bb)) {
225 p->st.sz_ipout += BLEN(bb);
230 /* --- @p_interval@ --- *
236 * Use: Called periodically to do tidying.
239 void p_interval(void)
244 reload = km_interval();
245 for (p = peers; p; p = pp) {
253 /* --- @p_stats@ --- *
255 * Arguments: @peer *p@ = pointer to a peer block
257 * Returns: A pointer to the peer's statistics.
260 stats *p_stats(peer *p) { return (&p->st); }
262 /* --- @p_ifname@ --- *
264 * Arguments: @peer *p@ = pointer to a peer block
266 * Returns: A pointer to the peer's interface name.
269 const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); }
271 /* --- @p_addr@ --- *
273 * Arguments: @peer *p@ = pointer to a peer block
275 * Returns: A pointer to the peer's address.
278 const addr *p_addr(peer *p) { return (&p->peer); }
280 /* --- @p_init@ --- *
282 * Arguments: @struct in_addr addr@ = address to bind to
283 * @unsigned port@ = port number to listen to
287 * Use: Initializes the peer system; creates the socket.
290 void p_init(struct in_addr addr, unsigned port)
293 struct sockaddr_in sin;
296 /* --- Note on socket buffer sizes --- *
298 * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer
299 * sizes I pass to @setsockopt@. I'm not putting special-case code here
300 * for Linux: BSD (at least TCPv2) does what I tell it rather than second-
304 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
305 die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno));
307 sin.sin_family = AF_INET;
309 sin.sin_port = htons(port);
310 if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
311 die(EXIT_FAILURE, "bind failed: %s", strerror(errno));
312 if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
313 setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) {
314 die(EXIT_FAILURE, "failed to set socket buffer sizes: %s",
317 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
318 sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0);
320 T( trace(T_PEER, "peer: created socket"); )
323 /* --- @p_port@ --- *
327 * Returns: Port number used for socket.
330 unsigned p_port(void)
333 size_t sz = sizeof(addr);
335 if (getsockname(sock.fd, &a.sa, &sz))
336 die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
337 assert(a.sa.sa_family == AF_INET);
338 return (ntohs(a.sin.sin_port));
341 /* --- @p_create@ --- *
343 * Arguments: @const char *name@ = name for this peer
344 * @struct sockaddr *sa@ = socket address of peer
345 * @size_t sz@ = size of socket address
347 * Returns: Pointer to the peer block, or null if it failed.
349 * Use: Creates a new named peer block. No peer is actually attached
353 peer *p_create(const char *name, struct sockaddr *sa, size_t sz)
355 peer *p = CREATE(peer);
356 T( trace(T_PEER, "peer: creating new peer `%s'", name); )
357 p->name = xstrdup(name);
360 memcpy(&p->peer.sa, sa, sz);
362 memset(&p->st, 0, sizeof(stats));
363 p->st.t_start = time(0);
364 if (kx_init(&p->kx, p, &p->ks))
366 if (tun_create(&p->t, p))
382 /* --- @p_name@ --- *
384 * Arguments: @peer *p@ = pointer to a peer block
386 * Returns: A pointer to the peer's name.
389 const char *p_name(peer *p) { return (p->name); }
391 /* --- @p_find@ --- *
393 * Arguments: @const char *name@ = name to look up
395 * Returns: Pointer to the peer block, or null if not found.
397 * Use: Finds a peer by name.
400 peer *p_find(const char *name)
403 for (p = peers; p; p = p->next) {
404 if (strcmp(name, p->name) == 0)
410 /* --- @p_destroy@ --- *
412 * Arguments: @peer *p@ = pointer to a peer
416 * Use: Destroys a peer.
419 void p_destroy(peer *p)
421 T( trace(T_PEER, "peer: destroying peer `%s'", p->name); )
427 p->next->prev = p->prev;
429 p->prev->next = p->next;
435 /* --- @p_first@, @p_next@ --- *
437 * Arguments: @peer *p@ = a peer block
439 * Returns: @peer_first@ returns the first peer in some ordering;
440 * @peer_next@ returns the peer following a given one in the
441 * same ordering. Null is returned for the end of the list.
444 peer *p_first(void) { return (peers); }
445 peer *p_next(peer *p) { return (p->next); }
447 /*----- That's all, folks -------------------------------------------------*/