410c8acf |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: peer.c,v 1.1 2001/02/03 20:26:37 mdw Exp $ |
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 $ |
32 | * Revision 1.1 2001/02/03 20:26:37 mdw |
33 | * Initial checkin. |
34 | * |
35 | */ |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #include "tripe.h" |
40 | |
41 | /*----- Static variables --------------------------------------------------*/ |
42 | |
43 | static peer *peers = 0; |
44 | static sel_file sock; |
45 | |
46 | /*----- Main code ---------------------------------------------------------*/ |
47 | |
48 | /* --- @p_read@ --- * |
49 | * |
50 | * Arguments: @int fd@ = file descriptor to read from |
51 | * @unsigned mode@ = what happened |
52 | * @void *v@ = an uninteresting pointer |
53 | * |
54 | * Returns: --- |
55 | * |
56 | * Use: Reads a packet from somewhere. |
57 | */ |
58 | |
59 | static void p_read(int fd, unsigned mode, void *v) |
60 | { |
61 | peer *p; |
62 | addr a; |
63 | size_t sz; |
64 | ssize_t n; |
65 | int ch; |
66 | buf b, bb; |
67 | |
68 | /* --- Read the data --- */ |
69 | |
70 | sz = sizeof(addr); |
71 | n = recvfrom(fd, buf_i, sizeof(buf_i), 0, &a.sa, &sz); |
72 | if (n < 0) { |
73 | a_warn("error reading socket: %s", strerror(errno)); |
74 | return; |
75 | } |
76 | |
77 | /* --- Find the appropriate peer --- */ |
78 | |
79 | assert(a.sa.sa_family == AF_INET); |
80 | T( trace(T_PEER, "packet from %s:%u", |
81 | inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port)); ) |
82 | for (p = peers; p; p = p->next) { |
83 | T( trace(T_PEER, "trying %s:%u", |
84 | inet_ntoa(p->peer.sin.sin_addr), (unsigned)ntohs(p->peer.sin.sin_port)); ) |
85 | if (p->peer.sin.sin_addr.s_addr == a.sin.sin_addr.s_addr && |
86 | p->peer.sin.sin_port == a.sin.sin_port) |
87 | goto found; |
88 | } |
89 | a_warn("packet from unexpected peer: %s:%u", |
90 | inet_ntoa(a.sin.sin_addr), (unsigned)ntohs(a.sin.sin_port)); |
91 | return; |
92 | |
93 | found: |
94 | T( trace(T_PEER, "peer: packet received from `%s'", p->name); |
95 | trace_block(T_PACKET, "peer: packet contents", buf_i, n); ) |
96 | |
97 | /* --- Pick the packet apart --- */ |
98 | |
99 | buf_init(&b, buf_i, n); |
100 | if ((ch = buf_getbyte(&b)) < 0) { |
101 | a_warn("bad packet from `%s': no type byte", p->name); |
102 | return; |
103 | } |
104 | switch (ch) { |
105 | case MSG_PACKET: |
106 | buf_init(&bb, buf_o, sizeof(buf_o)); |
107 | if (ks_decrypt(&p->ks, &b, &bb)) { |
108 | a_warn("couldn't decrypt inbound packet"); |
109 | return; |
110 | } |
111 | if (BOK(&bb)) |
112 | tun_inject(&p->t, &bb); |
113 | else |
114 | a_warn("packet build failed"); |
115 | break; |
116 | case MSG_PRECHALLENGE: |
117 | kx_prechallenge(&p->kx, &b); |
118 | break; |
119 | case MSG_CHALLENGE: |
120 | kx_challenge(&p->kx, &b); |
121 | break; |
122 | case MSG_RESPONSE: |
123 | kx_response(&p->kx, &b); |
124 | break; |
125 | default: |
126 | a_warn("bad packet from `%s': unknown packet type", p->name); |
127 | break; |
128 | } |
129 | } |
130 | |
131 | /* --- @p_txstart@ --- * |
132 | * |
133 | * Arguments: @peer *p@ = pointer to peer block |
134 | * @unsigned msg@ = message type code |
135 | * |
136 | * Returns: A pointer to a buffer to write to. |
137 | * |
138 | * Use: Starts sending to a peer. Only one send can happen at a |
139 | * time. |
140 | */ |
141 | |
142 | buf *p_txstart(peer *p, unsigned msg) |
143 | { |
144 | buf_init(&p->b, buf_o, sizeof(buf_o)); |
145 | buf_putbyte(&p->b, msg); |
146 | return (&p->b); |
147 | } |
148 | |
149 | /* --- @p_txend@ --- * |
150 | * |
151 | * Arguments: @peer *p@ = pointer to peer block |
152 | * |
153 | * Returns: --- |
154 | * |
155 | * Use: Sends a packet to the peer. |
156 | */ |
157 | |
158 | void p_txend(peer *p) |
159 | { |
160 | if (!BOK(&p->b)) { |
161 | a_warn("packet build failed"); |
162 | return; |
163 | } |
164 | IF_TRACING(T_PEER, trace_block(T_PACKET, "peer: sending packet", |
165 | BBASE(&p->b), BLEN(&p->b)); ) |
166 | if (sendto(sock.fd, BBASE(&p->b), BLEN(&p->b), |
167 | 0, &p->peer.sa, p->sasz) < 0) |
168 | a_warn("packet send to `%s' failed: %s", p->name, strerror(errno)); |
169 | } |
170 | |
171 | /* --- @p_tun@ --- * |
172 | * |
173 | * Arguments: @peer *p@ = pointer to peer block |
174 | * @buf *b@ = buffer containing incoming packet |
175 | * |
176 | * Returns: --- |
177 | * |
178 | * Use: Handles a packet which needs to be sent to a peer. |
179 | */ |
180 | |
181 | void p_tun(peer *p, buf *b) |
182 | { |
183 | buf *bb = p_txstart(p, MSG_PACKET); |
184 | if (ks_encrypt(&p->ks, b, bb)) |
185 | kx_start(&p->kx); |
186 | if (BCUR(bb) > BBASE(bb)) |
187 | p_txend(p); |
188 | } |
189 | |
190 | /* --- @p_interval@ --- * |
191 | * |
192 | * Arguments: --- |
193 | * |
194 | * Returns: --- |
195 | * |
196 | * Use: Called periodically to do tidying. |
197 | */ |
198 | |
199 | void p_interval(void) |
200 | { |
201 | peer *p, *pp; |
202 | int reload; |
203 | |
204 | reload = km_interval(); |
205 | for (p = peers; p; p = pp) { |
206 | pp = p->next; |
207 | if (reload) |
208 | kx_newkeys(&p->kx); |
209 | ks_prune(&p->ks); |
210 | } |
211 | } |
212 | |
213 | /* --- @p_ifname@ --- * |
214 | * |
215 | * Arguments: @peer *p@ = pointer to a peer block |
216 | * |
217 | * Returns: A pointer to the peer's interface name. |
218 | */ |
219 | |
220 | const char *p_ifname(peer *p) { return (tun_ifname(&p->t)); } |
221 | |
222 | /* --- @p_addr@ --- * |
223 | * |
224 | * Arguments: @peer *p@ = pointer to a peer block |
225 | * |
226 | * Returns: A pointer to the peer's address. |
227 | */ |
228 | |
229 | const addr *p_addr(peer *p) { return (&p->peer); } |
230 | |
231 | /* --- @p_init@ --- * |
232 | * |
233 | * Arguments: @unsigned port@ = port number to listen to |
234 | * |
235 | * Returns: --- |
236 | * |
237 | * Use: Initializes the peer system; creates the socket. |
238 | */ |
239 | |
240 | void p_init(unsigned port) |
241 | { |
242 | int fd; |
243 | struct sockaddr_in sin; |
244 | |
245 | if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0) |
246 | die(EXIT_FAILURE, "socket creation failed: %s", strerror(errno)); |
247 | BURN(sin); |
248 | sin.sin_family = AF_INET; |
249 | sin.sin_addr.s_addr = INADDR_ANY; |
250 | sin.sin_port = htons(port); |
251 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) |
252 | die(EXIT_FAILURE, "bind failed: %s", strerror(errno)); |
253 | sel_initfile(&sel, &sock, fd, SEL_READ, p_read, 0); |
254 | sel_addfile(&sock); |
255 | T( trace(T_PEER, "peer: created socket"); ) |
256 | } |
257 | |
258 | /* --- @p_port@ --- * |
259 | * |
260 | * Arguments: --- |
261 | * |
262 | * Returns: Port number used for socket. |
263 | */ |
264 | |
265 | unsigned p_port(void) |
266 | { |
267 | addr a; |
268 | size_t sz = sizeof(addr); |
269 | |
270 | if (getsockname(sock.fd, &a.sa, &sz)) |
271 | die(EXIT_FAILURE, "couldn't read port number: %s", strerror(errno)); |
272 | assert(a.sa.sa_family == AF_INET); |
273 | return (ntohs(a.sin.sin_port)); |
274 | } |
275 | |
276 | /* --- @p_create@ --- * |
277 | * |
278 | * Arguments: @const char *name@ = name for this peer |
279 | * @struct sockaddr *sa@ = socket address of peer |
280 | * @size_t sz@ = size of socket address |
281 | * |
282 | * Returns: Pointer to the peer block, or null if it failed. |
283 | * |
284 | * Use: Creates a new named peer block. No peer is actually attached |
285 | * by this point. |
286 | */ |
287 | |
288 | peer *p_create(const char *name, struct sockaddr *sa, size_t sz) |
289 | { |
290 | peer *p = CREATE(peer); |
291 | T( trace(T_PEER, "peer: creating new peer `%s'", name); ) |
292 | p->name = xstrdup(name); |
293 | p->ks = 0; |
294 | p->prev = 0; |
295 | memcpy(&p->peer.sa, sa, sz); |
296 | p->sasz = sz; |
297 | if (kx_init(&p->kx, p, &p->ks)) |
298 | goto tidy_0; |
299 | if (tun_create(&p->t, p)) |
300 | goto tidy_1; |
301 | p->next = peers; |
302 | if (peers) |
303 | peers->prev = p; |
304 | peers = p; |
305 | return (p); |
306 | |
307 | tidy_1: |
308 | kx_free(&p->kx); |
309 | tidy_0: |
310 | xfree(p->name); |
311 | DESTROY(p); |
312 | return (0); |
313 | } |
314 | |
315 | /* --- @p_name@ --- * |
316 | * |
317 | * Arguments: @peer *p@ = pointer to a peer block |
318 | * |
319 | * Returns: A pointer to the peer's name. |
320 | */ |
321 | |
322 | const char *p_name(peer *p) { return (p->name); } |
323 | |
324 | /* --- @p_find@ --- * |
325 | * |
326 | * Arguments: @const char *name@ = name to look up |
327 | * |
328 | * Returns: Pointer to the peer block, or null if not found. |
329 | * |
330 | * Use: Finds a peer by name. |
331 | */ |
332 | |
333 | peer *p_find(const char *name) |
334 | { |
335 | peer *p; |
336 | for (p = peers; p; p = p->next) { |
337 | if (strcmp(name, p->name) == 0) |
338 | return (p); |
339 | } |
340 | return (0); |
341 | } |
342 | |
343 | /* --- @p_destroy@ --- * |
344 | * |
345 | * Arguments: @peer *p@ = pointer to a peer |
346 | * |
347 | * Returns: --- |
348 | * |
349 | * Use: Destroys a peer. |
350 | */ |
351 | |
352 | void p_destroy(peer *p) |
353 | { |
354 | T( trace(T_PEER, "peer: destroying peer `%s'", p->name); ) |
355 | ks_free(&p->ks); |
356 | kx_free(&p->kx); |
357 | tun_destroy(&p->t); |
358 | xfree(p->name); |
359 | if (p->next) |
360 | p->next->prev = p->prev; |
361 | if (p->prev) |
362 | p->prev->next = p->next; |
363 | else |
364 | peers = p->next; |
365 | DESTROY(p); |
366 | } |
367 | |
368 | /* --- @p_first@, @p_next@ --- * |
369 | * |
370 | * Arguments: @peer *p@ = a peer block |
371 | * |
372 | * Returns: @peer_first@ returns the first peer in some ordering; |
373 | * @peer_next@ returns the peer following a given one in the |
374 | * same ordering. Null is returned for the end of the list. |
375 | */ |
376 | |
377 | peer *p_first(void) { return (peers); } |
378 | peer *p_next(peer *p) { return (p->next); } |
379 | |
380 | /*----- That's all, folks -------------------------------------------------*/ |