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1 | /* -*-c-*- |
2 | * |
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3 | * Forwarding UDP packets over a stream |
4 | * |
5 | * (c) 2003 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Trivial IP Encryption (TrIPE). |
11 | * |
12 | * TrIPE is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU General Public License as published by |
14 | * the Free Software Foundation; either version 2 of the License, or |
15 | * (at your option) any later version. |
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16 | * |
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17 | * TrIPE is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU General Public License |
23 | * along with TrIPE; if not, write to the Free Software Foundation, |
24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
25 | */ |
26 | |
07212ba4 |
27 | /*----- Header files ------------------------------------------------------*/ |
28 | |
29 | #include "config.h" |
30 | |
31 | #include <ctype.h> |
32 | #include <errno.h> |
33 | #include <stdio.h> |
34 | #include <stdlib.h> |
35 | #include <string.h> |
36 | |
37 | #include <sys/time.h> |
38 | #include <sys/types.h> |
39 | #include <unistd.h> |
40 | #include <fcntl.h> |
41 | #include <sys/uio.h> |
42 | #include <sys/socket.h> |
43 | #include <netinet/in.h> |
44 | #include <arpa/inet.h> |
45 | #include <netdb.h> |
46 | |
47 | #include <mLib/alloc.h> |
48 | #include <mLib/bits.h> |
49 | #include <mLib/dstr.h> |
50 | #include <mLib/fdflags.h> |
51 | #include <mLib/mdwopt.h> |
52 | #include <mLib/quis.h> |
53 | #include <mLib/report.h> |
54 | #include <mLib/sel.h> |
55 | #include <mLib/selpk.h> |
56 | |
57 | /*----- Data structures ---------------------------------------------------*/ |
58 | |
59 | typedef struct pk { |
60 | struct pk *next; /* Next packet in the chain */ |
61 | octet *p, *o; /* Buffer start and current posn */ |
62 | size_t n; /* Size of packet remaining */ |
63 | } pk; |
64 | |
65 | typedef struct pkstream { |
66 | unsigned f; /* Flags... */ |
67 | #define PKF_FULL 1u /* Buffer is full: stop reading */ |
68 | sel_file r, w; /* Read and write selectors */ |
69 | pk *pks, **pk_tail; /* Packet queue */ |
70 | size_t npk, szpk; /* Number and size of data */ |
71 | selpk p; /* Packet parser */ |
72 | } pkstream; |
73 | |
74 | typedef struct connwait { |
75 | sel_file a; /* Selector */ |
76 | struct sockaddr_in me; /* Who I'm meant to be */ |
77 | struct in_addr peer; /* Who my peer is */ |
78 | } connwait; |
79 | |
80 | /*----- Static variables --------------------------------------------------*/ |
81 | |
82 | static sel_state sel; |
83 | static connwait cw; |
84 | static int fd_udp; |
85 | static size_t pk_nmax = 128, pk_szmax = 1024 * 1024; |
86 | |
87 | /*----- Main code ---------------------------------------------------------*/ |
88 | |
89 | static int nonblockify(int fd) |
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90 | { return (fdflags(fd, O_NONBLOCK, O_NONBLOCK, 0, 0)); } |
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91 | |
92 | static int cloexec(int fd) |
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93 | { return (fdflags(fd, 0, 0, FD_CLOEXEC, FD_CLOEXEC)); } |
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94 | |
95 | static void dolisten(void); |
96 | |
97 | static void doclose(pkstream *p) |
98 | { |
99 | pk *pk, *ppk; |
100 | close(p->w.fd); |
101 | close(p->p.reader.fd); |
102 | selpk_destroy(&p->p); |
103 | if (!(p->f & PKF_FULL)) |
104 | sel_rmfile(&p->r); |
105 | if (p->npk) |
106 | sel_rmfile(&p->w); |
107 | for (pk = p->pks; pk; pk = ppk) { |
108 | ppk = pk->next; |
109 | xfree(pk->p); |
110 | xfree(pk); |
111 | } |
112 | xfree(p); |
113 | if (cw.me.sin_port != 0) |
114 | dolisten(); |
115 | else |
116 | exit(0); |
117 | } |
118 | |
119 | static void rdtcp(octet *b, size_t sz, pkbuf *pk, size_t *k, void *vp) |
120 | { |
121 | pkstream *p = vp; |
122 | size_t pksz; |
123 | |
124 | if (!sz) { |
125 | doclose(p); |
126 | return; |
127 | } |
128 | pksz = LOAD16(b); |
129 | if (pksz + 2 == sz) { |
130 | write(fd_udp, b + 2, pksz); |
131 | selpk_want(&p->p, 2); |
132 | } else { |
133 | selpk_want(&p->p, pksz + 2); |
134 | *k = sz; |
135 | } |
136 | } |
137 | |
138 | static void wrtcp(int fd, unsigned mode, void *vp) |
139 | { |
140 | #define NPK 16 |
141 | struct iovec iov[NPK]; |
142 | pkstream *p = vp; |
143 | size_t i; |
144 | ssize_t n; |
145 | pk *pk, *ppk; |
146 | |
147 | for (i = 0, pk = p->pks; i < NPK && pk; i++, pk = pk->next) { |
148 | iov[i].iov_base = pk->o; |
149 | iov[i].iov_len = pk->n; |
150 | } |
151 | |
152 | if ((n = writev(fd, iov, i)) < 0) { |
153 | if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) |
154 | return; |
155 | moan("couldn't write to TCP socket: %s", strerror(errno)); |
156 | doclose(p); |
157 | return; |
158 | } |
159 | |
160 | p->szpk -= n; |
161 | for (pk = p->pks; n && pk; pk = ppk) { |
162 | ppk = pk->next; |
163 | if (pk->n <= n) { |
164 | p->npk--; |
165 | n -= pk->n; |
166 | xfree(pk->p); |
167 | xfree(pk); |
168 | } else { |
169 | pk->n -= n; |
170 | pk->o += n; |
171 | break; |
172 | } |
173 | } |
174 | p->pks = pk; |
175 | if (!pk) { |
176 | p->pk_tail = &p->pks; |
177 | sel_rmfile(&p->w); |
178 | } |
179 | if ((p->f & PKF_FULL) && p->npk < pk_nmax && p->szpk < pk_szmax) { |
180 | p->f &= ~PKF_FULL; |
181 | sel_addfile(&p->r); |
182 | } |
183 | } |
184 | |
185 | static void rdudp(int fd, unsigned mode, void *vp) |
186 | { |
187 | octet buf[65536]; |
188 | ssize_t n; |
189 | pkstream *p = vp; |
190 | pk *pk; |
191 | |
192 | if ((n = read(fd, buf, sizeof(buf))) < 0) { |
193 | if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) |
194 | return; |
195 | moan("couldn't read from UDP socket: %s", strerror(errno)); |
196 | return; |
197 | } |
198 | pk = xmalloc(sizeof(*pk)); |
199 | pk->next = 0; |
200 | pk->p = xmalloc(n + 2); |
201 | STORE16(pk->p, n); |
202 | memcpy(pk->p + 2, buf, n); |
203 | pk->o = pk->p; |
204 | pk->n = n + 2; |
205 | *p->pk_tail = pk; |
206 | p->pk_tail = &pk->next; |
207 | if (!p->npk) |
208 | sel_addfile(&p->w); |
209 | sel_force(&p->w); |
210 | p->npk++; |
211 | p->szpk += n + 2; |
212 | if (p->npk >= pk_nmax || p->szpk >= pk_szmax) { |
213 | sel_rmfile(&p->r); |
214 | p->f |= PKF_FULL; |
215 | } |
216 | } |
217 | |
218 | static void dofwd(int fd_in, int fd_out) |
219 | { |
220 | pkstream *p = xmalloc(sizeof(*p)); |
221 | sel_initfile(&sel, &p->r, fd_udp, SEL_READ, rdudp, p); |
222 | sel_initfile(&sel, &p->w, fd_out, SEL_WRITE, wrtcp, p); |
223 | selpk_init(&p->p, &sel, fd_in, rdtcp, p); |
224 | selpk_want(&p->p, 2); |
225 | p->pks = 0; |
226 | p->pk_tail = &p->pks; |
227 | p->npk = p->szpk = 0; |
228 | p->f = 0; |
229 | sel_addfile(&p->r); |
230 | } |
231 | |
232 | static void doaccept(int fd_s, unsigned mode, void *p) |
233 | { |
234 | int fd; |
235 | struct sockaddr_in sin; |
236 | socklen_t sz = sizeof(sin); |
237 | |
238 | if ((fd = accept(fd_s, (struct sockaddr *)&sin, &sz)) < 0) { |
239 | if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) |
240 | return; |
241 | moan("couldn't accept incoming connection: %s", strerror(errno)); |
242 | return; |
243 | } |
244 | if (cw.peer.s_addr != INADDR_ANY && |
245 | cw.peer.s_addr != sin.sin_addr.s_addr) { |
246 | close(fd); |
247 | moan("rejecting connection from %s", inet_ntoa(sin.sin_addr)); |
248 | return; |
249 | } |
250 | if (nonblockify(fd) || cloexec(fd)) { |
251 | close(fd); |
252 | moan("couldn't accept incoming connection: %s", strerror(errno)); |
253 | return; |
254 | } |
255 | dofwd(fd, fd); |
256 | close(fd_s); |
257 | sel_rmfile(&cw.a); |
258 | } |
259 | |
260 | static void dolisten(void) |
261 | { |
262 | int fd; |
263 | int opt = 1; |
264 | |
265 | if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 || |
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266 | setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) || |
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267 | bind(fd, (struct sockaddr *)&cw.me, sizeof(cw.me)) || |
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268 | listen(fd, 1) || nonblockify(fd) || cloexec(fd)) |
269 | die(1, "couldn't set up listening socket: %s", strerror(errno)); |
270 | sel_initfile(&sel, &cw.a, fd, SEL_READ, doaccept, 0); |
271 | sel_addfile(&cw.a); |
272 | } |
273 | |
274 | static void parseaddr(const char *pp, struct in_addr *a, unsigned short *pt) |
275 | { |
276 | char *p = xstrdup(pp); |
277 | char *q = 0; |
278 | if (a && pt) { |
279 | strtok(p, ":"); |
280 | q = strtok(0, ""); |
281 | if (!q) |
282 | die(1, "missing port number in address `%s'", p); |
283 | } else if (pt) { |
284 | q = p; |
285 | } |
286 | |
287 | if (a) { |
288 | struct hostent *h; |
289 | if ((h = gethostbyname(p)) == 0) |
290 | die(1, "unknown host `%s'", p); |
291 | memcpy(a, h->h_addr, sizeof(*a)); |
292 | } |
293 | |
294 | if (pt) { |
295 | struct servent *s; |
296 | char *qq; |
297 | unsigned long n; |
298 | if ((s = getservbyname(q, "tcp")) != 0) |
299 | *pt = s->s_port; |
300 | else if ((n = strtoul(q, &qq, 0)) == 0 || *qq || n > 0xffff) |
301 | die(1, "bad port number `%s'", q); |
302 | else |
303 | *pt = htons(n); |
304 | } |
305 | } |
306 | |
307 | static void usage(FILE *fp) |
308 | { |
309 | pquis(fp, |
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310 | "Usage: $ [-l PORT] [-b ADDR] [-p ADDR] [-c ADDR:PORT]\n\ |
311 | ADDR:PORT ADDR:PORT\n"); |
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312 | } |
313 | |
314 | static void version(FILE *fp) |
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315 | { pquis(fp, "$, tripe version " VERSION "\n"); } |
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316 | |
317 | static void help(FILE *fp) |
318 | { |
319 | version(fp); |
320 | fputc('\n', fp); |
321 | usage(fp); |
322 | fputs("\n\ |
323 | Options:\n\ |
324 | \n\ |
325 | -h, --help Display this help text.\n\ |
326 | -v, --version Display version number.\n\ |
327 | -u, --usage Display pointless usage message.\n\ |
328 | \n\ |
329 | -l, --listen=PORT Listen for connections to TCP PORT.\n\ |
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330 | -p, --peer=ADDR Only accept connections from IP ADDR.\n\ |
331 | -b, --bind=ADDR Bind to ADDR before connecting.\n\ |
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332 | -c, --connect=ADDR:PORT Connect to IP ADDR, TCP PORT.\n\ |
333 | \n\ |
334 | Forwards UDP packets over a reliable stream. By default, uses stdin and\n\ |
335 | stdout; though it can use TCP sockets instead.\n\ |
336 | ", fp); |
337 | } |
338 | |
339 | int main(int argc, char *argv[]) |
340 | { |
341 | unsigned f = 0; |
342 | unsigned short pt; |
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343 | struct sockaddr_in connaddr, bindaddr; |
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344 | struct sockaddr_in udp_me, udp_peer; |
345 | int len = 65536; |
346 | |
347 | #define f_bogus 1u |
348 | |
349 | ego(argv[0]); |
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350 | bindaddr.sin_family = AF_INET; |
351 | bindaddr.sin_addr.s_addr = INADDR_ANY; |
352 | bindaddr.sin_port = 0; |
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353 | connaddr.sin_family = AF_INET; |
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354 | connaddr.sin_addr.s_addr = INADDR_ANY; |
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355 | cw.me.sin_family = AF_INET; |
356 | cw.me.sin_addr.s_addr = INADDR_ANY; |
357 | cw.me.sin_port = 0; |
358 | cw.peer.s_addr = INADDR_ANY; |
359 | sel_init(&sel); |
360 | for (;;) { |
361 | static struct option opt[] = { |
362 | { "help", 0, 0, 'h' }, |
363 | { "version", 0, 0, 'v' }, |
364 | { "usage", 0, 0, 'u' }, |
365 | { "listen", OPTF_ARGREQ, 0, 'l' }, |
366 | { "peer", OPTF_ARGREQ, 0, 'p' }, |
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367 | { "bind", OPTF_ARGREQ, 0, 'b' }, |
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368 | { "connect", OPTF_ARGREQ, 0, 'c' }, |
369 | { 0, 0, 0, 0 } |
370 | }; |
371 | int i; |
372 | |
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373 | i = mdwopt(argc, argv, "hvul:p:b:c:", opt, 0, 0, 0); |
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374 | if (i < 0) |
375 | break; |
376 | switch (i) { |
377 | case 'h': |
378 | help(stdout); |
379 | exit(0); |
380 | case 'v': |
381 | version(stdout); |
382 | exit(0); |
383 | case 'u': |
384 | usage(stdout); |
385 | exit(0); |
386 | case 'l': |
387 | parseaddr(optarg, 0, &pt); |
388 | cw.me.sin_port = pt; |
389 | break; |
390 | case 'p': |
391 | parseaddr(optarg, &cw.peer, 0); |
392 | break; |
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393 | case 'b': |
394 | parseaddr(optarg, &bindaddr.sin_addr, 0); |
395 | break; |
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396 | case 'c': |
397 | parseaddr(optarg, &connaddr.sin_addr, &pt); |
398 | connaddr.sin_port = pt; |
399 | break; |
400 | default: |
401 | f |= f_bogus; |
402 | break; |
403 | } |
404 | } |
405 | if (optind + 2 != argc || (f & f_bogus)) { |
406 | usage(stderr); |
407 | exit(1); |
408 | } |
409 | |
410 | udp_me.sin_family = udp_peer.sin_family = AF_INET; |
411 | parseaddr(argv[optind], &udp_me.sin_addr, &pt); |
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412 | udp_me.sin_port = pt; |
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413 | parseaddr(argv[optind + 1], &udp_peer.sin_addr, &pt); |
414 | udp_peer.sin_port = pt; |
415 | |
416 | if ((fd_udp = socket(PF_INET, SOCK_DGRAM, 0)) < 0 || |
417 | bind(fd_udp, (struct sockaddr *)&udp_me, sizeof(udp_me)) || |
418 | connect(fd_udp, (struct sockaddr *)&udp_peer, sizeof(udp_peer)) || |
419 | setsockopt(fd_udp, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) || |
420 | setsockopt(fd_udp, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)) || |
421 | nonblockify(fd_udp) || cloexec(fd_udp)) |
422 | die(1, "couldn't set up UDP socket: %s", strerror(errno)); |
423 | |
424 | if (cw.me.sin_port != 0) |
425 | dolisten(); |
426 | else if (connaddr.sin_addr.s_addr != INADDR_ANY) { |
427 | int fd; |
428 | if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0 || |
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429 | bind(fd, (struct sockaddr *)&bindaddr, sizeof(bindaddr)) || |
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430 | connect(fd, (struct sockaddr *)&connaddr, sizeof(connaddr)) || |
431 | nonblockify(fd) || cloexec(fd)) |
432 | die(1, "couldn't connect to TCP server: %s", strerror(errno)); |
433 | dofwd(fd, fd); |
434 | } else |
435 | dofwd(STDIN_FILENO, STDOUT_FILENO); |
436 | |
437 | for (;;) |
438 | sel_select(&sel); |
439 | return (0); |
440 | } |
441 | |
442 | /*----- That's all, folks -------------------------------------------------*/ |