3 * $Id: peer.c,v 1.3 2001/02/04 17:10:58 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 1.3 2001/02/04 17:10:58 mdw
33 * Make file descriptors be nonblocking and close-on-exec.
35 * Revision 1.2 2001/02/03 22:40:29 mdw
36 * Put timer information into the entropy pool when packets are received
37 * and on similar events. Reseed the generator on the interval timer.
39 * Revision 1.1 2001/02/03 20:26:37 mdw
44 /*----- Header files ------------------------------------------------------*/
48 /*----- Static variables --------------------------------------------------*/
50 static peer *peers = 0;
53 /*----- Main code ---------------------------------------------------------*/
57 * Arguments: @int fd@ = file descriptor to read from
58 * @unsigned mode@ = what happened
59 * @void *v@ = an uninteresting pointer
63 * Use: Reads a packet from somewhere.
66 static void p_read(int fd, unsigned mode, void *v)
75 /* --- Read the data --- */
79 n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz);
81 a_warn("error reading socket: %s", strerror(errno));
85 /* --- Find the appropriate peer --- */
87 assert(a.sa.sa_family == AF_INET);
88 for (p = peers; p; p = p->next) {
89 if (p->peer.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr &&
90 p->peer.sin.sin_port == a.sin.sin_port)
93 a_warn("packet from unexpected peer: %s:%u",
94 inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port));
98 T( trace(T_PEER, "peer: packet received from `%s'", p->name);
99 trace_block(T_PACKET, "peer: packet contents", buf_i, n); )
101 /* --- Pick the packet apart --- */
103 buf_init(&b, buf_i, n);
104 if ((ch = buf_getbyte(&b)) < 0) {
105 a_warn("bad packet from `%s': no type byte", p->name);
110 buf_init(&bb, buf_o, sizeof(buf_o));
111 if (ks_decrypt(&p->ks, &b, &bb)) {
112 a_warn("couldn't decrypt inbound packet");
116 tun_inject(&p->t, &bb);
118 a_warn("packet build failed");
120 case MSG_PRECHALLENGE:
121 kx_prechallenge(&p->kx, &b);
124 kx_challenge(&p->kx, &b);
127 kx_response(&p->kx, &b);
130 a_warn("bad packet from `%s': unknown packet type", p->name);
135 /* --- @p_txstart@ --- *
137 * Arguments: @peer *p@ = pointer to peer block
138 * @unsigned msg@ = message type code
140 * Returns: A pointer to a buffer to write to.
142 * Use: Starts sending to a peer. Only one send can happen at a
146 buf *p_txstart(peer *p, unsigned msg)
148 buf_init(&p->b, buf_o, sizeof(buf_o));
149 buf_putbyte(&p->b, msg);
153 /* --- @p_txend@ --- *
155 * Arguments: @peer *p@ = pointer to peer block
159 * Use: Sends a packet to the peer.
162 void p_txend(peer *p)
165 a_warn("packet build failed");
168 IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet",
169 BBASE(&p->b), BLEN(&p->b)); )
170 if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b),
171 0, &p->peer.sa, p->sasz) < 0)
172 a_warn("packet send to `%s' failed: %s", p->name, strerror(errno));
177 * Arguments: @peer *p@ = pointer to peer block
178 * @buf *b@ = buffer containing incoming packet
182 * Use: Handles a packet which needs to be sent to a peer.
185 void p_tun(peer *p, buf *b)
187 buf *bb = p_txstart(p, MSG_PACKET);
189 if (ks_encrypt(&p->ks, b, bb))
191 if (BCUR(bb) > BBASE(bb))
195 /* --- @p_interval@ --- *
201 * Use: Called periodically to do tidying.
204 void p_interval(void)
209 reload = km_interval();
210 for (p = peers; p; p = pp) {
218 /* --- @p_ifname@ --- *
220 * Arguments: @peer *p@ = pointer to a peer block
222 * Returns: A pointer to the peer's interface name.
225 const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); }
227 /* --- @p_addr@ --- *
229 * Arguments: @peer *p@ = pointer to a peer block
231 * Returns: A pointer to the peer's address.
234 const addr *p_addr(peer *p) { return (&p->peer); }
236 /* --- @p_init@ --- *
238 * Arguments: @unsigned port@ = port number to listen to
242 * Use: Initializes the peer system; creates the socket.
245 void p_init(unsigned port)
248 struct sockaddr_in sin;
250 if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
251 die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno));
253 sin.sin_family = AF_INET;
254 sin.sin_addr.s_addr = INADDR_ANY;
255 sin.sin_port = htons(port);
256 if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
257 die(EXIT_FAILURE, "bind failed: %s", strerror(errno));
258 fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
259 sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0);
261 T( trace(T_PEER, "peer: created socket"); )
264 /* --- @p_port@ --- *
268 * Returns: Port number used for socket.
271 unsigned p_port(void)
274 size_t sz = sizeof(addr);
276 if (getsockname(sock.fd, &a.sa, &sz))
277 die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno));
278 assert(a.sa.sa_family == AF_INET);
279 return (ntohs(a.sin.sin_port));
282 /* --- @p_create@ --- *
284 * Arguments: @const char *name@ = name for this peer
285 * @struct sockaddr *sa@ = socket address of peer
286 * @size_t sz@ = size of socket address
288 * Returns: Pointer to the peer block, or null if it failed.
290 * Use: Creates a new named peer block. No peer is actually attached
294 peer *p_create(const char *name, struct sockaddr *sa, size_t sz)
296 peer *p = CREATE(peer);
297 T( trace(T_PEER, "peer: creating new peer `%s'", name); )
298 p->name = xstrdup(name);
301 memcpy(&p->peer.sa, sa, sz);
303 if (kx_init(&p->kx, p, &p->ks))
305 if (tun_create(&p->t, p))
321 /* --- @p_name@ --- *
323 * Arguments: @peer *p@ = pointer to a peer block
325 * Returns: A pointer to the peer's name.
328 const char *p_name(peer *p) { return (p->name); }
330 /* --- @p_find@ --- *
332 * Arguments: @const char *name@ = name to look up
334 * Returns: Pointer to the peer block, or null if not found.
336 * Use: Finds a peer by name.
339 peer *p_find(const char *name)
342 for (p = peers; p; p = p->next) {
343 if (strcmp(name, p->name) == 0)
349 /* --- @p_destroy@ --- *
351 * Arguments: @peer *p@ = pointer to a peer
355 * Use: Destroys a peer.
358 void p_destroy(peer *p)
360 T( trace(T_PEER, "peer: destroying peer `%s'", p->name); )
366 p->next->prev = p->prev;
368 p->prev->next = p->next;
374 /* --- @p_first@, @p_next@ --- *
376 * Arguments: @peer *p@ = a peer block
378 * Returns: @peer_first@ returns the first peer in some ordering;
379 * @peer_next@ returns the peer following a given one in the
380 * same ordering. Null is returned for the end of the list.
383 peer *p_first(void) { return (peers); }
384 peer *p_next(peer *p) { return (p->next); }
386 /*----- That's all, folks -------------------------------------------------*/