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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: peer.c,v 1.4 2001/02/16 21:40:24 mdw Exp $ |
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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 $ |
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32 | * Revision 1.4 2001/02/16 21:40:24 mdw |
33 | * Change key exchange message interface. Maintain statistics. |
34 | * |
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35 | * Revision 1.3 2001/02/04 17:10:58 mdw |
36 | * Make file descriptors be nonblocking and close-on-exec. |
37 | * |
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38 | * Revision 1.2 2001/02/03 22:40:29 mdw |
39 | * Put timer information into the entropy pool when packets are received |
40 | * and on similar events. Reseed the generator on the interval timer. |
41 | * |
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42 | * Revision 1.1 2001/02/03 20:26:37 mdw |
43 | * Initial checkin. |
44 | * |
45 | */ |
46 | |
47 | /*----- Header files ------------------------------------------------------*/ |
48 | |
49 | #include "tripe.h" |
50 | |
51 | /*----- Static variables --------------------------------------------------*/ |
52 | |
53 | static peer *peers = 0; |
54 | static sel_file sock; |
55 | |
56 | /*----- Main code ---------------------------------------------------------*/ |
57 | |
58 | /* --- @p_read@ --- * |
59 | * |
60 | * Arguments: @int fd@ = file descriptor to read from |
61 | * @unsigned mode@ = what happened |
62 | * @void *v@ = an uninteresting pointer |
63 | * |
64 | * Returns: --- |
65 | * |
66 | * Use: Reads a packet from somewhere. |
67 | */ |
68 | |
69 | static void p_read(int fd, unsigned mode, void *v) |
70 | { |
71 | peer *p; |
72 | addr a; |
73 | size_t sz; |
74 | ssize_t n; |
75 | int ch; |
76 | buf b, bb; |
77 | |
78 | /* --- Read the data --- */ |
79 | |
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80 | TIMER; |
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81 | sz = sizeof(addr); |
82 | n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz); |
83 | if (n < 0) { |
84 | a_warn("error reading socket: %s", strerror(errno)); |
85 | return; |
86 | } |
87 | |
88 | /* --- Find the appropriate peer --- */ |
89 | |
90 | assert(a.sa.sa_family == AF_INET); |
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91 | for (p = peers; p; p = p->next) { |
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92 | if (p->peer.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr && |
93 | p->peer.sin.sin_port == a.sin.sin_port) |
94 | goto found; |
95 | } |
96 | a_warn("packet from unexpected peer: %s:%u", |
97 | inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port)); |
98 | return; |
99 | |
100 | found: |
101 | T( trace(T_PEER, "peer: packet received from `%s'", p->name); |
102 | trace_block(T_PACKET, "peer: packet contents", buf_i, n); ) |
103 | |
104 | /* --- Pick the packet apart --- */ |
105 | |
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106 | p->st.t_last = time(0); |
107 | p->st.n_in++; |
108 | p->st.sz_in += n; |
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109 | buf_init(&b, buf_i, n); |
110 | if ((ch = buf_getbyte(&b)) < 0) { |
111 | a_warn("bad packet from `%s': no type byte", p->name); |
112 | return; |
113 | } |
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114 | switch (ch & MSG_CATMASK) { |
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115 | case MSG_PACKET: |
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116 | if (ch & MSG_TYPEMASK) { |
117 | a_warn("unknown packet type from `%s'", p->name); |
118 | p->st.n_reject++; |
119 | return; |
120 | } |
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121 | buf_init(&bb, buf_o, sizeof(buf_o)); |
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122 | if (ksl_decrypt(&p->ks, &b, &bb)) { |
123 | p->st.n_reject++; |
124 | a_warn("couldn't decrypt inbound packet from `%s'", p->name); |
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125 | return; |
126 | } |
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127 | if (BOK(&bb)) { |
128 | p->st.n_ipin++; |
129 | p->st.sz_ipin += BSZ(&b); |
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130 | tun_inject(&p->t, &bb); |
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131 | } else { |
132 | p->st.n_reject++; |
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133 | a_warn("packet build failed"); |
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134 | } |
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135 | break; |
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136 | case MSG_KEYEXCH: |
137 | kx_message(&p->kx, ch & MSG_TYPEMASK, &b); |
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138 | break; |
139 | default: |
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140 | p->st.n_reject++; |
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141 | a_warn("bad packet from `%s': unknown packet type", p->name); |
142 | break; |
143 | } |
144 | } |
145 | |
146 | /* --- @p_txstart@ --- * |
147 | * |
148 | * Arguments: @peer *p@ = pointer to peer block |
149 | * @unsigned msg@ = message type code |
150 | * |
151 | * Returns: A pointer to a buffer to write to. |
152 | * |
153 | * Use: Starts sending to a peer. Only one send can happen at a |
154 | * time. |
155 | */ |
156 | |
157 | buf *p_txstart(peer *p, unsigned msg) |
158 | { |
159 | buf_init(&p->b, buf_o, sizeof(buf_o)); |
160 | buf_putbyte(&p->b, msg); |
161 | return (&p->b); |
162 | } |
163 | |
164 | /* --- @p_txend@ --- * |
165 | * |
166 | * Arguments: @peer *p@ = pointer to peer block |
167 | * |
168 | * Returns: --- |
169 | * |
170 | * Use: Sends a packet to the peer. |
171 | */ |
172 | |
173 | void p_txend(peer *p) |
174 | { |
175 | if (!BOK(&p->b)) { |
176 | a_warn("packet build failed"); |
177 | return; |
178 | } |
179 | IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet", |
180 | BBASE(&p->b), BLEN(&p->b)); ) |
181 | if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b), |
182 | 0, &p->peer.sa, p->sasz) < 0) |
183 | a_warn("packet send to `%s' failed: %s", p->name, strerror(errno)); |
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184 | else { |
185 | p->st.n_out++; |
186 | p->st.sz_out += BLEN(&p->b); |
187 | } |
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188 | } |
189 | |
190 | /* --- @p_tun@ --- * |
191 | * |
192 | * Arguments: @peer *p@ = pointer to peer block |
193 | * @buf *b@ = buffer containing incoming packet |
194 | * |
195 | * Returns: --- |
196 | * |
197 | * Use: Handles a packet which needs to be sent to a peer. |
198 | */ |
199 | |
200 | void p_tun(peer *p, buf *b) |
201 | { |
202 | buf *bb = p_txstart(p, MSG_PACKET); |
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203 | TIMER; |
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204 | if (ksl_encrypt(&p->ks, b, bb)) |
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205 | kx_start(&p->kx); |
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206 | if (BOK(bb) && BLEN(bb)) { |
207 | p->st.n_ipout++; |
208 | p->st.sz_ipout += BLEN(bb); |
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209 | p_txend(p); |
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210 | } |
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211 | } |
212 | |
213 | /* --- @p_interval@ --- * |
214 | * |
215 | * Arguments: --- |
216 | * |
217 | * Returns: --- |
218 | * |
219 | * Use: Called periodically to do tidying. |
220 | */ |
221 | |
222 | void p_interval(void) |
223 | { |
224 | peer *p, *pp; |
225 | int reload; |
226 | |
227 | reload = km_interval(); |
228 | for (p = peers; p; p = pp) { |
229 | pp = p->next; |
230 | if (reload) |
231 | kx_newkeys(&p->kx); |
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232 | ksl_prune(&p->ks); |
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233 | } |
234 | } |
235 | |
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236 | /* --- @p_stats@ --- * |
237 | * |
238 | * Arguments: @peer *p@ = pointer to a peer block |
239 | * |
240 | * Returns: A pointer to the peer's statistics. |
241 | */ |
242 | |
243 | stats *p_stats(peer *p) { return (&p->st); } |
244 | |
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245 | /* --- @p_ifname@ --- * |
246 | * |
247 | * Arguments: @peer *p@ = pointer to a peer block |
248 | * |
249 | * Returns: A pointer to the peer's interface name. |
250 | */ |
251 | |
252 | const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); } |
253 | |
254 | /* --- @p_addr@ --- * |
255 | * |
256 | * Arguments: @peer *p@ = pointer to a peer block |
257 | * |
258 | * Returns: A pointer to the peer's address. |
259 | */ |
260 | |
261 | const addr *p_addr(peer *p) { return (&p->peer); } |
262 | |
263 | /* --- @p_init@ --- * |
264 | * |
265 | * Arguments: @unsigned port@ = port number to listen to |
266 | * |
267 | * Returns: --- |
268 | * |
269 | * Use: Initializes the peer system; creates the socket. |
270 | */ |
271 | |
272 | void p_init(unsigned port) |
273 | { |
274 | int fd; |
275 | struct sockaddr_in sin; |
276 | |
277 | if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) |
278 | die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno)); |
279 | BURN(sin); |
280 | sin.sin_family = AF_INET; |
281 | sin.sin_addr.s_addr = INADDR_ANY; |
282 | sin.sin_port = htons(port); |
283 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) |
284 | die(EXIT_FAILURE, "bind failed: %s", strerror(errno)); |
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285 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
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286 | sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0); |
287 | sel_addfile(&sock); |
288 | T( trace(T_PEER, "peer: created socket"); ) |
289 | } |
290 | |
291 | /* --- @p_port@ --- * |
292 | * |
293 | * Arguments: --- |
294 | * |
295 | * Returns: Port number used for socket. |
296 | */ |
297 | |
298 | unsigned p_port(void) |
299 | { |
300 | addr a; |
301 | size_t sz = sizeof(addr); |
302 | |
303 | if (getsockname(sock.fd, &a.sa, &sz)) |
304 | die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno)); |
305 | assert(a.sa.sa_family == AF_INET); |
306 | return (ntohs(a.sin.sin_port)); |
307 | } |
308 | |
309 | /* --- @p_create@ --- * |
310 | * |
311 | * Arguments: @const char *name@ = name for this peer |
312 | * @struct sockaddr *sa@ = socket address of peer |
313 | * @size_t sz@ = size of socket address |
314 | * |
315 | * Returns: Pointer to the peer block, or null if it failed. |
316 | * |
317 | * Use: Creates a new named peer block. No peer is actually attached |
318 | * by this point. |
319 | */ |
320 | |
321 | peer *p_create(const char *name, struct sockaddr *sa, size_t sz) |
322 | { |
323 | peer *p = CREATE(peer); |
324 | T( trace(T_PEER, "peer: creating new peer `%s'", name); ) |
325 | p->name = xstrdup(name); |
326 | p->ks = 0; |
327 | p->prev = 0; |
328 | memcpy(&p->peer.sa, sa, sz); |
329 | p->sasz = sz; |
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330 | memset(&p->st, 0, sizeof(stats)); |
331 | p->st.t_start = time(0); |
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332 | if (kx_init(&p->kx, p, &p->ks)) |
333 | goto tidy_0; |
334 | if (tun_create(&p->t, p)) |
335 | goto tidy_1; |
336 | p->next = peers; |
337 | if (peers) |
338 | peers->prev = p; |
339 | peers = p; |
340 | return (p); |
341 | |
342 | tidy_1: |
343 | kx_free(&p->kx); |
344 | tidy_0: |
345 | xfree(p->name); |
346 | DESTROY(p); |
347 | return (0); |
348 | } |
349 | |
350 | /* --- @p_name@ --- * |
351 | * |
352 | * Arguments: @peer *p@ = pointer to a peer block |
353 | * |
354 | * Returns: A pointer to the peer's name. |
355 | */ |
356 | |
357 | const char *p_name(peer *p) { return (p->name); } |
358 | |
359 | /* --- @p_find@ --- * |
360 | * |
361 | * Arguments: @const char *name@ = name to look up |
362 | * |
363 | * Returns: Pointer to the peer block, or null if not found. |
364 | * |
365 | * Use: Finds a peer by name. |
366 | */ |
367 | |
368 | peer *p_find(const char *name) |
369 | { |
370 | peer *p; |
371 | for (p = peers; p; p = p->next) { |
372 | if (strcmp(name, p->name) == 0) |
373 | return (p); |
374 | } |
375 | return (0); |
376 | } |
377 | |
378 | /* --- @p_destroy@ --- * |
379 | * |
380 | * Arguments: @peer *p@ = pointer to a peer |
381 | * |
382 | * Returns: --- |
383 | * |
384 | * Use: Destroys a peer. |
385 | */ |
386 | |
387 | void p_destroy(peer *p) |
388 | { |
389 | T( trace(T_PEER, "peer: destroying peer `%s'", p->name); ) |
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390 | ksl_free(&p->ks); |
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391 | kx_free(&p->kx); |
392 | tun_destroy(&p->t); |
393 | xfree(p->name); |
394 | if (p->next) |
395 | p->next->prev = p->prev; |
396 | if (p->prev) |
397 | p->prev->next = p->next; |
398 | else |
399 | peers = p->next; |
400 | DESTROY(p); |
401 | } |
402 | |
403 | /* --- @p_first@, @p_next@ --- * |
404 | * |
405 | * Arguments: @peer *p@ = a peer block |
406 | * |
407 | * Returns: @peer_first@ returns the first peer in some ordering; |
408 | * @peer_next@ returns the peer following a given one in the |
409 | * same ordering. Null is returned for the end of the list. |
410 | */ |
411 | |
412 | peer *p_first(void) { return (peers); } |
413 | peer *p_next(peer *p) { return (p->next); } |
414 | |
415 | /*----- That's all, folks -------------------------------------------------*/ |