410c8acf |
1 | /* -*-c-*- |
2 | * |
3cdc3f3a |
3 | * $Id$ |
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 | |
410c8acf |
29 | /*----- Header files ------------------------------------------------------*/ |
30 | |
31 | #include "tripe.h" |
32 | |
33 | /*----- Static variables --------------------------------------------------*/ |
34 | |
35 | static peer *peers = 0; |
36 | static sel_file sock; |
37 | |
38 | /*----- Main code ---------------------------------------------------------*/ |
39 | |
40 | /* --- @p_read@ --- * |
41 | * |
42 | * Arguments: @int fd@ = file descriptor to read from |
43 | * @unsigned mode@ = what happened |
44 | * @void *v@ = an uninteresting pointer |
45 | * |
46 | * Returns: --- |
47 | * |
48 | * Use: Reads a packet from somewhere. |
49 | */ |
50 | |
51 | static void p_read(int fd, unsigned mode, void *v) |
52 | { |
53 | peer *p; |
54 | addr a; |
55 | size_t sz; |
56 | ssize_t n; |
57 | int ch; |
58 | buf b, bb; |
59 | |
60 | /* --- Read the data --- */ |
61 | |
8d0c7a83 |
62 | TIMER; |
410c8acf |
63 | sz = sizeof(addr); |
64 | n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz); |
65 | if (n < 0) { |
3cdc3f3a |
66 | a_warn("PEER - socket-read-error -- %s", strerror(errno)); |
410c8acf |
67 | return; |
68 | } |
69 | |
70 | /* --- Find the appropriate peer --- */ |
71 | |
72 | assert(a.sa.sa_family == AF_INET); |
410c8acf |
73 | for (p = peers; p; p = p->next) { |
410c8acf |
74 | if (p->peer.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr && |
75 | p->peer.sin.sin_port == a.sin.sin_port) |
76 | goto found; |
77 | } |
3cdc3f3a |
78 | a_warn("PEER - unexpected-source INET %s %u", |
79 | inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port)); |
410c8acf |
80 | return; |
81 | |
82 | found: |
83 | T( trace(T_PEER, "peer: packet received from `%s'", p->name); |
84 | trace_block(T_PACKET, "peer: packet contents", buf_i, n); ) |
85 | |
86 | /* --- Pick the packet apart --- */ |
87 | |
5bb41301 |
88 | p->st.t_last = time(0); |
89 | p->st.n_in++; |
90 | p->st.sz_in += n; |
410c8acf |
91 | buf_init(&b, buf_i, n); |
92 | if ((ch = buf_getbyte(&b)) < 0) { |
3cdc3f3a |
93 | a_warn("PEER %s bad-packet no-type", p->name); |
410c8acf |
94 | return; |
95 | } |
5bb41301 |
96 | switch (ch & MSG_CATMASK) { |
410c8acf |
97 | case MSG_PACKET: |
5bb41301 |
98 | if (ch & MSG_TYPEMASK) { |
3cdc3f3a |
99 | a_warn("PEER %s bad-packet unknown-type 0x%02x", p->name, ch); |
5bb41301 |
100 | p->st.n_reject++; |
101 | return; |
102 | } |
410c8acf |
103 | buf_init(&bb, buf_o, sizeof(buf_o)); |
7ed14135 |
104 | if (ksl_decrypt(&p->ks, MSG_PACKET, &b, &bb)) { |
5bb41301 |
105 | p->st.n_reject++; |
3cdc3f3a |
106 | a_warn("PEER %s decrypt-failed", p->name); |
410c8acf |
107 | return; |
108 | } |
5bb41301 |
109 | if (BOK(&bb)) { |
110 | p->st.n_ipin++; |
111 | p->st.sz_ipin += BSZ(&b); |
410c8acf |
112 | tun_inject(&p->t, &bb); |
5bb41301 |
113 | } else { |
114 | p->st.n_reject++; |
3cdc3f3a |
115 | a_warn("PEER %s packet-build-failed", p->name); |
5bb41301 |
116 | } |
410c8acf |
117 | break; |
5bb41301 |
118 | case MSG_KEYEXCH: |
119 | kx_message(&p->kx, ch & MSG_TYPEMASK, &b); |
410c8acf |
120 | break; |
121 | default: |
5bb41301 |
122 | p->st.n_reject++; |
3cdc3f3a |
123 | a_warn("PEER %s bad-packet unknown-category 0x%02x", p->name, ch); |
410c8acf |
124 | break; |
125 | } |
126 | } |
127 | |
128 | /* --- @p_txstart@ --- * |
129 | * |
130 | * Arguments: @peer *p@ = pointer to peer block |
131 | * @unsigned msg@ = message type code |
132 | * |
133 | * Returns: A pointer to a buffer to write to. |
134 | * |
135 | * Use: Starts sending to a peer. Only one send can happen at a |
136 | * time. |
137 | */ |
138 | |
139 | buf *p_txstart(peer *p, unsigned msg) |
140 | { |
141 | buf_init(&p->b, buf_o, sizeof(buf_o)); |
142 | buf_putbyte(&p->b, msg); |
143 | return (&p->b); |
144 | } |
145 | |
146 | /* --- @p_txend@ --- * |
147 | * |
148 | * Arguments: @peer *p@ = pointer to peer block |
149 | * |
150 | * Returns: --- |
151 | * |
152 | * Use: Sends a packet to the peer. |
153 | */ |
154 | |
155 | void p_txend(peer *p) |
156 | { |
157 | if (!BOK(&p->b)) { |
3cdc3f3a |
158 | a_warn("PEER %s packet-build-failed", p->name); |
410c8acf |
159 | return; |
160 | } |
161 | IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet", |
162 | BBASE(&p->b), BLEN(&p->b)); ) |
163 | if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b), |
164 | 0, &p->peer.sa, p->sasz) < 0) |
3cdc3f3a |
165 | a_warn("PEER %s socket-write-error -- %s", p->name, strerror(errno)); |
5bb41301 |
166 | else { |
167 | p->st.n_out++; |
168 | p->st.sz_out += BLEN(&p->b); |
169 | } |
410c8acf |
170 | } |
171 | |
172 | /* --- @p_tun@ --- * |
173 | * |
174 | * Arguments: @peer *p@ = pointer to peer block |
175 | * @buf *b@ = buffer containing incoming packet |
176 | * |
177 | * Returns: --- |
178 | * |
179 | * Use: Handles a packet which needs to be sent to a peer. |
180 | */ |
181 | |
182 | void p_tun(peer *p, buf *b) |
183 | { |
184 | buf *bb = p_txstart(p, MSG_PACKET); |
7b052fe6 |
185 | |
8d0c7a83 |
186 | TIMER; |
7ed14135 |
187 | if (ksl_encrypt(&p->ks, MSG_PACKET, b, bb)) |
410c8acf |
188 | kx_start(&p->kx); |
5bb41301 |
189 | if (BOK(bb) && BLEN(bb)) { |
190 | p->st.n_ipout++; |
191 | p->st.sz_ipout += BLEN(bb); |
410c8acf |
192 | p_txend(p); |
5bb41301 |
193 | } |
410c8acf |
194 | } |
195 | |
196 | /* --- @p_interval@ --- * |
197 | * |
198 | * Arguments: --- |
199 | * |
200 | * Returns: --- |
201 | * |
202 | * Use: Called periodically to do tidying. |
203 | */ |
204 | |
205 | void p_interval(void) |
206 | { |
207 | peer *p, *pp; |
208 | int reload; |
209 | |
210 | reload = km_interval(); |
211 | for (p = peers; p; p = pp) { |
212 | pp = p->next; |
213 | if (reload) |
214 | kx_newkeys(&p->kx); |
5bb41301 |
215 | ksl_prune(&p->ks); |
410c8acf |
216 | } |
217 | } |
218 | |
5bb41301 |
219 | /* --- @p_stats@ --- * |
220 | * |
221 | * Arguments: @peer *p@ = pointer to a peer block |
222 | * |
223 | * Returns: A pointer to the peer's statistics. |
224 | */ |
225 | |
226 | stats *p_stats(peer *p) { return (&p->st); } |
227 | |
410c8acf |
228 | /* --- @p_ifname@ --- * |
229 | * |
230 | * Arguments: @peer *p@ = pointer to a peer block |
231 | * |
232 | * Returns: A pointer to the peer's interface name. |
233 | */ |
234 | |
235 | const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); } |
236 | |
237 | /* --- @p_addr@ --- * |
238 | * |
239 | * Arguments: @peer *p@ = pointer to a peer block |
240 | * |
241 | * Returns: A pointer to the peer's address. |
242 | */ |
243 | |
244 | const addr *p_addr(peer *p) { return (&p->peer); } |
245 | |
246 | /* --- @p_init@ --- * |
247 | * |
767b36e2 |
248 | * Arguments: @struct in_addr addr@ = address to bind to |
249 | * @unsigned port@ = port number to listen to |
410c8acf |
250 | * |
251 | * Returns: --- |
252 | * |
253 | * Use: Initializes the peer system; creates the socket. |
254 | */ |
255 | |
767b36e2 |
256 | void p_init(struct in_addr addr, unsigned port) |
410c8acf |
257 | { |
258 | int fd; |
259 | struct sockaddr_in sin; |
df9dfccf |
260 | int len = PKBUFSZ; |
0a9920e2 |
261 | |
262 | /* --- Note on socket buffer sizes --- * |
263 | * |
264 | * For some bizarre reason, Linux 2.2 (at least) doubles the socket buffer |
265 | * sizes I pass to @setsockopt@. I'm not putting special-case code here |
266 | * for Linux: BSD (at least TCPv2) does what I tell it rather than second- |
267 | * guessing me. |
268 | */ |
410c8acf |
269 | |
270 | if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) |
271 | die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno)); |
272 | BURN(sin); |
273 | sin.sin_family = AF_INET; |
767b36e2 |
274 | sin.sin_addr = addr; |
410c8acf |
275 | sin.sin_port = htons(port); |
276 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) |
277 | die(EXIT_FAILURE, "bind failed: %s", strerror(errno)); |
0a9920e2 |
278 | if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) || |
279 | setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len))) { |
280 | die(EXIT_FAILURE, "failed to set socket buffer sizes: %s", |
281 | strerror(errno)); |
282 | } |
650a6624 |
283 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
410c8acf |
284 | sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0); |
285 | sel_addfile(&sock); |
286 | T( trace(T_PEER, "peer: created socket"); ) |
287 | } |
288 | |
289 | /* --- @p_port@ --- * |
290 | * |
291 | * Arguments: --- |
292 | * |
293 | * Returns: Port number used for socket. |
294 | */ |
295 | |
296 | unsigned p_port(void) |
297 | { |
298 | addr a; |
299 | size_t sz = sizeof(addr); |
300 | |
301 | if (getsockname(sock.fd, &a.sa, &sz)) |
302 | die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno)); |
303 | assert(a.sa.sa_family == AF_INET); |
304 | return (ntohs(a.sin.sin_port)); |
305 | } |
306 | |
307 | /* --- @p_create@ --- * |
308 | * |
309 | * Arguments: @const char *name@ = name for this peer |
310 | * @struct sockaddr *sa@ = socket address of peer |
311 | * @size_t sz@ = size of socket address |
312 | * |
313 | * Returns: Pointer to the peer block, or null if it failed. |
314 | * |
315 | * Use: Creates a new named peer block. No peer is actually attached |
316 | * by this point. |
317 | */ |
318 | |
319 | peer *p_create(const char *name, struct sockaddr *sa, size_t sz) |
320 | { |
321 | peer *p = CREATE(peer); |
322 | T( trace(T_PEER, "peer: creating new peer `%s'", name); ) |
323 | p->name = xstrdup(name); |
324 | p->ks = 0; |
325 | p->prev = 0; |
326 | memcpy(&p->peer.sa, sa, sz); |
327 | p->sasz = sz; |
5bb41301 |
328 | memset(&p->st, 0, sizeof(stats)); |
329 | p->st.t_start = time(0); |
410c8acf |
330 | if (kx_init(&p->kx, p, &p->ks)) |
331 | goto tidy_0; |
332 | if (tun_create(&p->t, p)) |
333 | goto tidy_1; |
334 | p->next = peers; |
335 | if (peers) |
336 | peers->prev = p; |
337 | peers = p; |
3cdc3f3a |
338 | switch (p->peer.sa.sa_family) { |
339 | case AF_INET: |
340 | a_notify("ADD %s INET %s %u", |
341 | name, |
342 | inet_ntoa(p->peer.sin.sin_addr), |
343 | (unsigned)ntohs(p->peer.sin.sin_port)); |
344 | break; |
345 | default: |
346 | a_notify("ADD %s UNKNOWN", name); |
347 | break; |
348 | } |
410c8acf |
349 | return (p); |
350 | |
351 | tidy_1: |
352 | kx_free(&p->kx); |
353 | tidy_0: |
354 | xfree(p->name); |
355 | DESTROY(p); |
356 | return (0); |
357 | } |
358 | |
359 | /* --- @p_name@ --- * |
360 | * |
361 | * Arguments: @peer *p@ = pointer to a peer block |
362 | * |
363 | * Returns: A pointer to the peer's name. |
364 | */ |
365 | |
366 | const char *p_name(peer *p) { return (p->name); } |
367 | |
368 | /* --- @p_find@ --- * |
369 | * |
370 | * Arguments: @const char *name@ = name to look up |
371 | * |
372 | * Returns: Pointer to the peer block, or null if not found. |
373 | * |
374 | * Use: Finds a peer by name. |
375 | */ |
376 | |
377 | peer *p_find(const char *name) |
378 | { |
379 | peer *p; |
380 | for (p = peers; p; p = p->next) { |
381 | if (strcmp(name, p->name) == 0) |
382 | return (p); |
383 | } |
384 | return (0); |
385 | } |
386 | |
387 | /* --- @p_destroy@ --- * |
388 | * |
389 | * Arguments: @peer *p@ = pointer to a peer |
390 | * |
391 | * Returns: --- |
392 | * |
393 | * Use: Destroys a peer. |
394 | */ |
395 | |
396 | void p_destroy(peer *p) |
397 | { |
398 | T( trace(T_PEER, "peer: destroying peer `%s'", p->name); ) |
3cdc3f3a |
399 | a_notify("KILL %s", p->name); |
5bb41301 |
400 | ksl_free(&p->ks); |
410c8acf |
401 | kx_free(&p->kx); |
402 | tun_destroy(&p->t); |
403 | xfree(p->name); |
404 | if (p->next) |
405 | p->next->prev = p->prev; |
406 | if (p->prev) |
407 | p->prev->next = p->next; |
408 | else |
409 | peers = p->next; |
410 | DESTROY(p); |
411 | } |
412 | |
413 | /* --- @p_first@, @p_next@ --- * |
414 | * |
415 | * Arguments: @peer *p@ = a peer block |
416 | * |
417 | * Returns: @peer_first@ returns the first peer in some ordering; |
418 | * @peer_next@ returns the peer following a given one in the |
419 | * same ordering. Null is returned for the end of the list. |
420 | */ |
421 | |
422 | peer *p_first(void) { return (peers); } |
423 | peer *p_next(peer *p) { return (p->next); } |
424 | |
425 | /*----- That's all, folks -------------------------------------------------*/ |