410c8acf |
1 | /* -*-c-*- |
2 | * |
767b36e2 |
3 | * $Id: peer.c,v 1.8 2003/05/16 12:09:03 mdw Exp $ |
410c8acf |
4 | * |
5 | * Communication with the peer |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Trivial IP Encryption (TrIPE). |
13 | * |
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. |
18 | * |
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. |
23 | * |
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. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: peer.c,v $ |
767b36e2 |
32 | * Revision 1.8 2003/05/16 12:09:03 mdw |
33 | * Allow binding to a chosen address. |
34 | * |
7b052fe6 |
35 | * Revision 1.7 2003/04/15 14:12:05 mdw |
36 | * Insert a newline to improve readability. |
37 | * |
df9dfccf |
38 | * Revision 1.6 2001/06/19 22:07:59 mdw |
39 | * Use magic number for packet size. |
40 | * |
0a9920e2 |
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. |
47 | * |
5bb41301 |
48 | * Revision 1.4 2001/02/16 21:40:24 mdw |
49 | * Change key exchange message interface. Maintain statistics. |
50 | * |
650a6624 |
51 | * Revision 1.3 2001/02/04 17:10:58 mdw |
52 | * Make file descriptors be nonblocking and close-on-exec. |
53 | * |
8d0c7a83 |
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. |
57 | * |
410c8acf |
58 | * Revision 1.1 2001/02/03 20:26:37 mdw |
59 | * Initial checkin. |
60 | * |
61 | */ |
62 | |
63 | /*----- Header files ------------------------------------------------------*/ |
64 | |
65 | #include "tripe.h" |
66 | |
67 | /*----- Static variables --------------------------------------------------*/ |
68 | |
69 | static peer *peers = 0; |
70 | static sel_file sock; |
71 | |
72 | /*----- Main code ---------------------------------------------------------*/ |
73 | |
74 | /* --- @p_read@ --- * |
75 | * |
76 | * Arguments: @int fd@ = file descriptor to read from |
77 | * @unsigned mode@ = what happened |
78 | * @void *v@ = an uninteresting pointer |
79 | * |
80 | * Returns: --- |
81 | * |
82 | * Use: Reads a packet from somewhere. |
83 | */ |
84 | |
85 | static void p_read(int fd, unsigned mode, void *v) |
86 | { |
87 | peer *p; |
88 | addr a; |
89 | size_t sz; |
90 | ssize_t n; |
91 | int ch; |
92 | buf b, bb; |
93 | |
94 | /* --- Read the data --- */ |
95 | |
8d0c7a83 |
96 | TIMER; |
410c8acf |
97 | sz = sizeof(addr); |
98 | n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz); |
99 | if (n < 0) { |
100 | a_warn("error reading socket: %s", strerror(errno)); |
101 | return; |
102 | } |
103 | |
104 | /* --- Find the appropriate peer --- */ |
105 | |
106 | assert(a.sa.sa_family == AF_INET); |
410c8acf |
107 | for (p = peers; p; p = p->next) { |
410c8acf |
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) |
110 | goto found; |
111 | } |
112 | a_warn("packet from unexpected peer: %s:%u", |
113 | inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port)); |
114 | return; |
115 | |
116 | found: |
117 | T( trace(T_PEER, "peer: packet received from `%s'", p->name); |
118 | trace_block(T_PACKET, "peer: packet contents", buf_i, n); ) |
119 | |
120 | /* --- Pick the packet apart --- */ |
121 | |
5bb41301 |
122 | p->st.t_last = time(0); |
123 | p->st.n_in++; |
124 | p->st.sz_in += n; |
410c8acf |
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); |
128 | return; |
129 | } |
5bb41301 |
130 | switch (ch & MSG_CATMASK) { |
410c8acf |
131 | case MSG_PACKET: |
5bb41301 |
132 | if (ch & MSG_TYPEMASK) { |
133 | a_warn("unknown packet type from `%s'", p->name); |
134 | p->st.n_reject++; |
135 | return; |
136 | } |
410c8acf |
137 | buf_init(&bb, buf_o, sizeof(buf_o)); |
5bb41301 |
138 | if (ksl_decrypt(&p->ks, &b, &bb)) { |
139 | p->st.n_reject++; |
140 | a_warn("couldn't decrypt inbound packet from `%s'", p->name); |
410c8acf |
141 | return; |
142 | } |
5bb41301 |
143 | if (BOK(&bb)) { |
144 | p->st.n_ipin++; |
145 | p->st.sz_ipin += BSZ(&b); |
410c8acf |
146 | tun_inject(&p->t, &bb); |
5bb41301 |
147 | } else { |
148 | p->st.n_reject++; |
410c8acf |
149 | a_warn("packet build failed"); |
5bb41301 |
150 | } |
410c8acf |
151 | break; |
5bb41301 |
152 | case MSG_KEYEXCH: |
153 | kx_message(&p->kx, ch & MSG_TYPEMASK, &b); |
410c8acf |
154 | break; |
155 | default: |
5bb41301 |
156 | p->st.n_reject++; |
410c8acf |
157 | a_warn("bad packet from `%s': unknown packet type", p->name); |
158 | break; |
159 | } |
160 | } |
161 | |
162 | /* --- @p_txstart@ --- * |
163 | * |
164 | * Arguments: @peer *p@ = pointer to peer block |
165 | * @unsigned msg@ = message type code |
166 | * |
167 | * Returns: A pointer to a buffer to write to. |
168 | * |
169 | * Use: Starts sending to a peer. Only one send can happen at a |
170 | * time. |
171 | */ |
172 | |
173 | buf *p_txstart(peer *p, unsigned msg) |
174 | { |
175 | buf_init(&p->b, buf_o, sizeof(buf_o)); |
176 | buf_putbyte(&p->b, msg); |
177 | return (&p->b); |
178 | } |
179 | |
180 | /* --- @p_txend@ --- * |
181 | * |
182 | * Arguments: @peer *p@ = pointer to peer block |
183 | * |
184 | * Returns: --- |
185 | * |
186 | * Use: Sends a packet to the peer. |
187 | */ |
188 | |
189 | void p_txend(peer *p) |
190 | { |
191 | if (!BOK(&p->b)) { |
192 | a_warn("packet build failed"); |
193 | return; |
194 | } |
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)); |
5bb41301 |
200 | else { |
201 | p->st.n_out++; |
202 | p->st.sz_out += BLEN(&p->b); |
203 | } |
410c8acf |
204 | } |
205 | |
206 | /* --- @p_tun@ --- * |
207 | * |
208 | * Arguments: @peer *p@ = pointer to peer block |
209 | * @buf *b@ = buffer containing incoming packet |
210 | * |
211 | * Returns: --- |
212 | * |
213 | * Use: Handles a packet which needs to be sent to a peer. |
214 | */ |
215 | |
216 | void p_tun(peer *p, buf *b) |
217 | { |
218 | buf *bb = p_txstart(p, MSG_PACKET); |
7b052fe6 |
219 | |
8d0c7a83 |
220 | TIMER; |
5bb41301 |
221 | if (ksl_encrypt(&p->ks, b, bb)) |
410c8acf |
222 | kx_start(&p->kx); |
5bb41301 |
223 | if (BOK(bb) && BLEN(bb)) { |
224 | p->st.n_ipout++; |
225 | p->st.sz_ipout += BLEN(bb); |
410c8acf |
226 | p_txend(p); |
5bb41301 |
227 | } |
410c8acf |
228 | } |
229 | |
230 | /* --- @p_interval@ --- * |
231 | * |
232 | * Arguments: --- |
233 | * |
234 | * Returns: --- |
235 | * |
236 | * Use: Called periodically to do tidying. |
237 | */ |
238 | |
239 | void p_interval(void) |
240 | { |
241 | peer *p, *pp; |
242 | int reload; |
243 | |
244 | reload = km_interval(); |
245 | for (p = peers; p; p = pp) { |
246 | pp = p->next; |
247 | if (reload) |
248 | kx_newkeys(&p->kx); |
5bb41301 |
249 | ksl_prune(&p->ks); |
410c8acf |
250 | } |
251 | } |
252 | |
5bb41301 |
253 | /* --- @p_stats@ --- * |
254 | * |
255 | * Arguments: @peer *p@ = pointer to a peer block |
256 | * |
257 | * Returns: A pointer to the peer's statistics. |
258 | */ |
259 | |
260 | stats *p_stats(peer *p) { return (&p->st); } |
261 | |
410c8acf |
262 | /* --- @p_ifname@ --- * |
263 | * |
264 | * Arguments: @peer *p@ = pointer to a peer block |
265 | * |
266 | * Returns: A pointer to the peer's interface name. |
267 | */ |
268 | |
269 | const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); } |
270 | |
271 | /* --- @p_addr@ --- * |
272 | * |
273 | * Arguments: @peer *p@ = pointer to a peer block |
274 | * |
275 | * Returns: A pointer to the peer's address. |
276 | */ |
277 | |
278 | const addr *p_addr(peer *p) { return (&p->peer); } |
279 | |
280 | /* --- @p_init@ --- * |
281 | * |
767b36e2 |
282 | * Arguments: @struct in_addr addr@ = address to bind to |
283 | * @unsigned port@ = port number to listen to |
410c8acf |
284 | * |
285 | * Returns: --- |
286 | * |
287 | * Use: Initializes the peer system; creates the socket. |
288 | */ |
289 | |
767b36e2 |
290 | void p_init(struct in_addr addr, unsigned port) |
410c8acf |
291 | { |
292 | int fd; |
293 | struct sockaddr_in sin; |
df9dfccf |
294 | int len = PKBUFSZ; |
0a9920e2 |
295 | |
296 | /* --- Note on socket buffer sizes --- * |
297 | * |
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- |
301 | * guessing me. |
302 | */ |
410c8acf |
303 | |
304 | if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) |
305 | die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno)); |
306 | BURN(sin); |
307 | sin.sin_family = AF_INET; |
767b36e2 |
308 | sin.sin_addr = addr; |
410c8acf |
309 | sin.sin_port = htons(port); |
310 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) |
311 | die(EXIT_FAILURE, "bind failed: %s", strerror(errno)); |
0a9920e2 |
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", |
315 | strerror(errno)); |
316 | } |
650a6624 |
317 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
410c8acf |
318 | sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0); |
319 | sel_addfile(&sock); |
320 | T( trace(T_PEER, "peer: created socket"); ) |
321 | } |
322 | |
323 | /* --- @p_port@ --- * |
324 | * |
325 | * Arguments: --- |
326 | * |
327 | * Returns: Port number used for socket. |
328 | */ |
329 | |
330 | unsigned p_port(void) |
331 | { |
332 | addr a; |
333 | size_t sz = sizeof(addr); |
334 | |
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)); |
339 | } |
340 | |
341 | /* --- @p_create@ --- * |
342 | * |
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 |
346 | * |
347 | * Returns: Pointer to the peer block, or null if it failed. |
348 | * |
349 | * Use: Creates a new named peer block. No peer is actually attached |
350 | * by this point. |
351 | */ |
352 | |
353 | peer *p_create(const char *name, struct sockaddr *sa, size_t sz) |
354 | { |
355 | peer *p = CREATE(peer); |
356 | T( trace(T_PEER, "peer: creating new peer `%s'", name); ) |
357 | p->name = xstrdup(name); |
358 | p->ks = 0; |
359 | p->prev = 0; |
360 | memcpy(&p->peer.sa, sa, sz); |
361 | p->sasz = sz; |
5bb41301 |
362 | memset(&p->st, 0, sizeof(stats)); |
363 | p->st.t_start = time(0); |
410c8acf |
364 | if (kx_init(&p->kx, p, &p->ks)) |
365 | goto tidy_0; |
366 | if (tun_create(&p->t, p)) |
367 | goto tidy_1; |
368 | p->next = peers; |
369 | if (peers) |
370 | peers->prev = p; |
371 | peers = p; |
372 | return (p); |
373 | |
374 | tidy_1: |
375 | kx_free(&p->kx); |
376 | tidy_0: |
377 | xfree(p->name); |
378 | DESTROY(p); |
379 | return (0); |
380 | } |
381 | |
382 | /* --- @p_name@ --- * |
383 | * |
384 | * Arguments: @peer *p@ = pointer to a peer block |
385 | * |
386 | * Returns: A pointer to the peer's name. |
387 | */ |
388 | |
389 | const char *p_name(peer *p) { return (p->name); } |
390 | |
391 | /* --- @p_find@ --- * |
392 | * |
393 | * Arguments: @const char *name@ = name to look up |
394 | * |
395 | * Returns: Pointer to the peer block, or null if not found. |
396 | * |
397 | * Use: Finds a peer by name. |
398 | */ |
399 | |
400 | peer *p_find(const char *name) |
401 | { |
402 | peer *p; |
403 | for (p = peers; p; p = p->next) { |
404 | if (strcmp(name, p->name) == 0) |
405 | return (p); |
406 | } |
407 | return (0); |
408 | } |
409 | |
410 | /* --- @p_destroy@ --- * |
411 | * |
412 | * Arguments: @peer *p@ = pointer to a peer |
413 | * |
414 | * Returns: --- |
415 | * |
416 | * Use: Destroys a peer. |
417 | */ |
418 | |
419 | void p_destroy(peer *p) |
420 | { |
421 | T( trace(T_PEER, "peer: destroying peer `%s'", p->name); ) |
5bb41301 |
422 | ksl_free(&p->ks); |
410c8acf |
423 | kx_free(&p->kx); |
424 | tun_destroy(&p->t); |
425 | xfree(p->name); |
426 | if (p->next) |
427 | p->next->prev = p->prev; |
428 | if (p->prev) |
429 | p->prev->next = p->next; |
430 | else |
431 | peers = p->next; |
432 | DESTROY(p); |
433 | } |
434 | |
435 | /* --- @p_first@, @p_next@ --- * |
436 | * |
437 | * Arguments: @peer *p@ = a peer block |
438 | * |
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. |
442 | */ |
443 | |
444 | peer *p_first(void) { return (peers); } |
445 | peer *p_next(peer *p) { return (p->next); } |
446 | |
447 | /*----- That's all, folks -------------------------------------------------*/ |