3 * $Id: peer.c,v 1.7 2003/04/15 14:12:05 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 1.7 2003/04/15 14:12:05 mdw
33 * Insert a newline to improve readability.
35 * Revision 1.6 2001/06/19 22:07:59 mdw
36 * Use magic number for packet size.
38 * Revision 1.5 2001/03/03 11:15:19 mdw
39 * Set the socket send and receive buffers to maximum. At least this way,
40 * we won't drop large packets on the floor. If the administrator wants to
41 * prevent fragmentation of TrIPE messages, he can lower the MTU on the
42 * tunnel interface. Getting path-MTU stuff out of the kernel is too much
43 * system-specific hard work for this program.
45 * Revision 1.4 2001/02/16 21:40:24 mdw
46 * Change key exchange message interface. Maintain statistics.
48 * Revision 1.3 2001/02/04 17:10:58 mdw
49 * Make file descriptors be nonblocking and close-on-exec.
51 * Revision 1.2 2001/02/03 22:40:29 mdw
52 * Put timer information into the entropy pool when packets are received
53 * and on similar events. Reseed the generator on the interval timer.
55 * Revision 1.1 2001/02/03 20:26:37 mdw
60 /*----- Header files ------------------------------------------------------*/
64 /*----- Static variables --------------------------------------------------*/
66 static peer
*peers
= 0;
69 /*----- Main code ---------------------------------------------------------*/
73 * Arguments: @int fd@ = file descriptor to read from
74 * @unsigned mode@ = what happened
75 * @void *v@ = an uninteresting pointer
79 * Use: Reads a packet from somewhere.
82 static void p_read(int fd
, unsigned mode
, void *v
)
91 /* --- Read the data --- */
95 n
= recvfrom(fd
, buf_i
, sizeof(buf_i
), 0, &a
.sa
, &sz
);
97 a_warn("error reading socket: %s", strerror(errno
));
101 /* --- Find the appropriate peer --- */
103 assert(a
.sa
.sa_family
== AF_INET
);
104 for (p
= peers
; p
; p
= p
->next
) {
105 if (p
->peer
.sin
.sin_addr
.s_addr
== a
.sin
.sin_addr
.s_addr
&&
106 p
->peer
.sin
.sin_port
== a
.sin
.sin_port
)
109 a_warn("packet from unexpected peer: %s:%u",
110 inet_ntoa(a
.sin
.sin_addr
), (unsigned)ntohs(a
.sin
.sin_port
));
114 T( trace(T_PEER
, "peer: packet received from `%s'", p
->name
);
115 trace_block(T_PACKET
, "peer: packet contents", buf_i
, n
); )
117 /* --- Pick the packet apart --- */
119 p
->st
.t_last
= time(0);
122 buf_init(&b
, buf_i
, n
);
123 if ((ch
= buf_getbyte(&b
)) < 0) {
124 a_warn("bad packet from `%s': no type byte", p
->name
);
127 switch (ch
& MSG_CATMASK
) {
129 if (ch
& MSG_TYPEMASK
) {
130 a_warn("unknown packet type from `%s'", p
->name
);
134 buf_init(&bb
, buf_o
, sizeof(buf_o
));
135 if (ksl_decrypt(&p
->ks
, &b
, &bb
)) {
137 a_warn("couldn't decrypt inbound packet from `%s'", p
->name
);
142 p
->st
.sz_ipin
+= BSZ(&b
);
143 tun_inject(&p
->t
, &bb
);
146 a_warn("packet build failed");
150 kx_message(&p
->kx
, ch
& MSG_TYPEMASK
, &b
);
154 a_warn("bad packet from `%s': unknown packet type", p
->name
);
159 /* --- @p_txstart@ --- *
161 * Arguments: @peer *p@ = pointer to peer block
162 * @unsigned msg@ = message type code
164 * Returns: A pointer to a buffer to write to.
166 * Use: Starts sending to a peer. Only one send can happen at a
170 buf
*p_txstart(peer
*p
, unsigned msg
)
172 buf_init(&p
->b
, buf_o
, sizeof(buf_o
));
173 buf_putbyte(&p
->b
, msg
);
177 /* --- @p_txend@ --- *
179 * Arguments: @peer *p@ = pointer to peer block
183 * Use: Sends a packet to the peer.
186 void p_txend(peer
*p
)
189 a_warn("packet build failed");
192 IF_TRACING(T_PEER
, trace_block(T_PACKET
, "peer: sending packet",
193 BBASE(&p
->b
), BLEN(&p
->b
)); )
194 if (sendto(sock
.fd
, BBASE(&p
->b
), BLEN(&p
->b
),
195 0, &p
->peer
.sa
, p
->sasz
) < 0)
196 a_warn("packet send to `%s' failed: %s", p
->name
, strerror(errno
));
199 p
->st
.sz_out
+= BLEN(&p
->b
);
205 * Arguments: @peer *p@ = pointer to peer block
206 * @buf *b@ = buffer containing incoming packet
210 * Use: Handles a packet which needs to be sent to a peer.
213 void p_tun(peer
*p
, buf
*b
)
215 buf
*bb
= p_txstart(p
, MSG_PACKET
);
218 if (ksl_encrypt(&p
->ks
, b
, bb
))
220 if (BOK(bb
) && BLEN(bb
)) {
222 p
->st
.sz_ipout
+= BLEN(bb
);
227 /* --- @p_interval@ --- *
233 * Use: Called periodically to do tidying.
236 void p_interval(void)
241 reload
= km_interval();
242 for (p
= peers
; p
; p
= pp
) {
250 /* --- @p_stats@ --- *
252 * Arguments: @peer *p@ = pointer to a peer block
254 * Returns: A pointer to the peer's statistics.
257 stats
*p_stats(peer
*p
) { return (&p
->st
); }
259 /* --- @p_ifname@ --- *
261 * Arguments: @peer *p@ = pointer to a peer block
263 * Returns: A pointer to the peer's interface name.
266 const char *p_ifname(peer
*p
) { return (tun_ifname(&p
->t
)); }
268 /* --- @p_addr@ --- *
270 * Arguments: @peer *p@ = pointer to a peer block
272 * Returns: A pointer to the peer's address.
275 const addr
*p_addr(peer
*p
) { return (&p
->peer
); }
277 /* --- @p_init@ --- *
279 * Arguments: @unsigned port@ = port number to listen to
283 * Use: Initializes the peer system; creates the socket.
286 void p_init(unsigned port
)
289 struct sockaddr_in sin
;
292 /* --- Note on socket buffer sizes --- *
294 * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer
295 * sizes I pass to @setsockopt@. I'm not putting special-case code here
296 * for Linux: BSD (at least TCPv2) does what I tell it rather than second-
300 if ((fd
= socket(PF_INET
, SOCK_DGRAM
, 0)) < 0)
301 die(EXIT_FAILURE
, "socket creation failed: %s", strerror(errno
));
303 sin
.sin_family
= AF_INET
;
304 sin
.sin_addr
.s_addr
= INADDR_ANY
;
305 sin
.sin_port
= htons(port
);
306 if (bind(fd
, (struct sockaddr
*)&sin
, sizeof(sin
)))
307 die(EXIT_FAILURE
, "bind failed: %s", strerror(errno
));
308 if (setsockopt(fd
, SOL_SOCKET
, SO_RCVBUF
, &len
, sizeof(len
)) ||
309 setsockopt(fd
, SOL_SOCKET
, SO_SNDBUF
, &len
, sizeof(len
))) {
310 die(EXIT_FAILURE
, "failed to set socket buffer sizes: %s",
313 fdflags(fd
, O_NONBLOCK
, O_NONBLOCK
, FD_CLOEXEC
, FD_CLOEXEC
);
314 sel_initfile(&sel
, &sock
, fd
, SEL_READ
, p_read
, 0);
316 T( trace(T_PEER
, "peer: created socket"); )
319 /* --- @p_port@ --- *
323 * Returns: Port number used for socket.
326 unsigned p_port(void)
329 size_t sz
= sizeof(addr
);
331 if (getsockname(sock
.fd
, &a
.sa
, &sz
))
332 die(EXIT_FAILURE
, "couldn't read port number: %s", strerror(errno
));
333 assert(a
.sa
.sa_family
== AF_INET
);
334 return (ntohs(a
.sin
.sin_port
));
337 /* --- @p_create@ --- *
339 * Arguments: @const char *name@ = name for this peer
340 * @struct sockaddr *sa@ = socket address of peer
341 * @size_t sz@ = size of socket address
343 * Returns: Pointer to the peer block, or null if it failed.
345 * Use: Creates a new named peer block. No peer is actually attached
349 peer
*p_create(const char *name
, struct sockaddr
*sa
, size_t sz
)
351 peer
*p
= CREATE(peer
);
352 T( trace(T_PEER
, "peer: creating new peer `%s'", name
); )
353 p
->name
= xstrdup(name
);
356 memcpy(&p
->peer
.sa
, sa
, sz
);
358 memset(&p
->st
, 0, sizeof(stats
));
359 p
->st
.t_start
= time(0);
360 if (kx_init(&p
->kx
, p
, &p
->ks
))
362 if (tun_create(&p
->t
, p
))
378 /* --- @p_name@ --- *
380 * Arguments: @peer *p@ = pointer to a peer block
382 * Returns: A pointer to the peer's name.
385 const char *p_name(peer
*p
) { return (p
->name
); }
387 /* --- @p_find@ --- *
389 * Arguments: @const char *name@ = name to look up
391 * Returns: Pointer to the peer block, or null if not found.
393 * Use: Finds a peer by name.
396 peer
*p_find(const char *name
)
399 for (p
= peers
; p
; p
= p
->next
) {
400 if (strcmp(name
, p
->name
) == 0)
406 /* --- @p_destroy@ --- *
408 * Arguments: @peer *p@ = pointer to a peer
412 * Use: Destroys a peer.
415 void p_destroy(peer
*p
)
417 T( trace(T_PEER
, "peer: destroying peer `%s'", p
->name
); )
423 p
->next
->prev
= p
->prev
;
425 p
->prev
->next
= p
->next
;
431 /* --- @p_first@, @p_next@ --- *
433 * Arguments: @peer *p@ = a peer block
435 * Returns: @peer_first@ returns the first peer in some ordering;
436 * @peer_next@ returns the peer following a given one in the
437 * same ordering. Null is returned for the end of the list.
440 peer
*p_first(void) { return (peers
); }
441 peer
*p_next(peer
*p
) { return (p
->next
); }
443 /*----- That's all, folks -------------------------------------------------*/