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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: inet.c,v 1.5 2003/11/25 14:08:23 mdw Exp $ |
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4 | * |
5 | * Protocol specific definitions for IPv4 sockets |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of the `fw' port forwarder. |
13 | * |
14 | * `fw' 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 | * `fw' 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 `fw'; 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: inet.c,v $ |
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32 | * Revision 1.5 2003/11/25 14:08:23 mdw |
33 | * Debianization. Socket target options. Internet binding. |
34 | * |
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35 | * Revision 1.4 2002/01/13 14:49:56 mdw |
36 | * Conditional compilation for @getnetbyname@, since Cygwin doesn't have |
37 | * it. |
38 | * |
bc241e98 |
39 | * Revision 1.3 2000/08/01 17:59:56 mdw |
40 | * Switch over to using `size_t' for socket address lengths. |
41 | * |
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42 | * Revision 1.2 1999/07/27 18:30:53 mdw |
43 | * Various minor portability fixes. |
44 | * |
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45 | * Revision 1.1 1999/07/26 23:34:11 mdw |
46 | * New socket address types. |
47 | * |
48 | */ |
49 | |
50 | /*----- Header files ------------------------------------------------------*/ |
51 | |
52 | #include "config.h" |
53 | |
54 | #include <ctype.h> |
55 | #include <errno.h> |
56 | #include <stdio.h> |
57 | #include <stdlib.h> |
58 | #include <string.h> |
59 | |
60 | #include <sys/types.h> |
61 | #include <unistd.h> |
62 | |
63 | #include <sys/socket.h> |
64 | #include <netinet/in.h> |
65 | #include <arpa/inet.h> |
66 | #include <netdb.h> |
67 | |
68 | #include <mLib/alloc.h> |
69 | #include <mLib/dstr.h> |
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70 | #include <mLib/fdflags.h> |
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71 | #include <mLib/report.h> |
72 | #include <mLib/sub.h> |
73 | |
74 | #include "acl.h" |
75 | #include "addr.h" |
76 | #include "conf.h" |
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77 | #include "fw.h" |
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78 | #include "identify.h" |
79 | #include "inet.h" |
80 | #include "reffd.h" |
81 | #include "scan.h" |
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82 | #include "socket.h" |
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83 | |
84 | /*----- Data structures ---------------------------------------------------*/ |
85 | |
86 | typedef struct inet_addrx { |
87 | addr a; |
88 | struct sockaddr_in sin; |
89 | } inet_addrx; |
90 | |
91 | typedef struct inet_opts { |
92 | addr_opts ao; |
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93 | struct in_addr bind; |
94 | } inet_opts; |
95 | |
96 | typedef struct inet_srcopts { |
97 | inet_opts io; |
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98 | acl_entry *acl; |
99 | acl_entry **acltail; |
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100 | } inet_srcopts; |
101 | |
102 | typedef struct inet_targopts { |
103 | inet_opts io; |
104 | } inet_targopts; |
105 | |
106 | static inet_srcopts inet_globalsrc = |
107 | { { { 0 }, { INADDR_ANY } }, 0, &inet_globalsrc.acl }; |
108 | static inet_targopts inet_globaltarg = |
109 | { { { 0 }, { INADDR_ANY } } }; |
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110 | |
111 | /*----- Protocol operations -----------------------------------------------*/ |
112 | |
113 | /* --- @read@ --- */ |
114 | |
115 | static addr *inet_read(scanner *sc, unsigned type) |
116 | { |
117 | inet_addrx *ia = xmalloc(sizeof(*ia)); |
118 | |
119 | ia->a.ops = &inet_ops; |
120 | ia->a.sz = sizeof(struct sockaddr_in); |
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121 | memset(&ia->sin, 0, sizeof(ia->sin)); |
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122 | ia->sin.sin_family = AF_INET; |
123 | |
124 | /* --- Read the host address part --- */ |
125 | |
126 | switch (type) { |
127 | case ADDR_SRC: |
128 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "port") == 0) |
129 | token(sc); |
130 | ia->sin.sin_addr.s_addr = htonl(INADDR_ANY); |
131 | break; |
132 | case ADDR_DEST: { |
133 | struct hostent *h; |
134 | dstr d = DSTR_INIT; |
135 | conf_name(sc, '.', &d); |
136 | if ((h = gethostbyname(d.buf)) == 0) |
137 | error(sc, "couldn't resolve Internet address `%s'", d.buf); |
138 | memcpy(&ia->sin.sin_addr, h->h_addr, sizeof(struct in_addr)); |
139 | dstr_destroy(&d); |
140 | if (sc->t == ':') |
141 | token(sc); |
142 | } break; |
143 | } |
144 | |
145 | /* --- Read the port number --- */ |
146 | |
147 | { |
148 | struct servent *s; |
149 | |
150 | if (sc->t != CTOK_WORD) |
151 | error(sc, "parse error, TCP port expected"); |
152 | if (isdigit((unsigned char)sc->d.buf[0])) |
153 | ia->sin.sin_port = htons(atoi(sc->d.buf)); |
154 | else if ((s = getservbyname(sc->d.buf, "tcp")) == 0) |
155 | error(sc, "unknown tcp service `%s'", sc->d.buf); |
156 | else |
157 | ia->sin.sin_port = s->s_port; |
158 | token(sc); |
159 | } |
160 | |
161 | return (&ia->a); |
162 | } |
163 | |
164 | /* --- @destroy@ --- */ |
165 | |
166 | static void inet_destroy(addr *a) |
167 | { |
168 | inet_addrx *ia = (inet_addrx *)a; |
169 | DESTROY(ia); |
170 | } |
171 | |
172 | /* --- @print@ --- */ |
173 | |
174 | static void inet_print(addr *a, unsigned type, dstr *d) |
175 | { |
176 | inet_addrx *ia = (inet_addrx *)a; |
177 | switch (type) { |
178 | case ADDR_SRC: |
179 | dstr_putf(d, "inet:%u", (unsigned)ntohs(ia->sin.sin_port)); |
180 | break; |
181 | case ADDR_DEST: |
182 | dstr_putf(d, "inet:%s:%u", |
183 | inet_ntoa(ia->sin.sin_addr), |
184 | (unsigned)ntohs(ia->sin.sin_port)); |
185 | break; |
186 | } |
187 | } |
188 | |
189 | /* --- @initopts@ --- */ |
190 | |
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191 | static addr_opts *inet_initsrcopts(void) |
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192 | { |
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193 | inet_srcopts *io = CREATE(inet_srcopts); |
194 | *io = inet_globalsrc; |
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195 | io->acl = 0; |
196 | io->acltail = &io->acl; |
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197 | return (&io->io.ao); |
198 | } |
199 | |
200 | static addr_opts *inet_inittargopts(void) |
201 | { |
202 | inet_targopts *io = CREATE(inet_targopts); |
203 | *io = inet_globaltarg; |
204 | return (&io->io.ao); |
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205 | } |
206 | |
207 | /* --- @option@ --- */ |
208 | |
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209 | static void addropt(scanner *sc, inet_opts *io) |
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210 | { |
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211 | dstr d = DSTR_INIT; |
212 | struct hostent *h; |
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213 | |
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214 | token(sc); |
215 | if (sc->t == '=') |
216 | token(sc); |
217 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "any") == 0) |
218 | io->bind.s_addr = INADDR_ANY; |
219 | else { |
220 | conf_name(sc, '.', &d); |
221 | if ((h = gethostbyname(d.buf)) == 0) |
222 | error(sc, "couldn't resolve address `%s'", d.buf); |
223 | memcpy(&io->bind, h->h_addr, sizeof(struct in_addr)); |
224 | } |
225 | } |
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226 | |
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227 | static int srcopt(scanner *sc, addr_opts *ao) |
228 | { |
229 | inet_srcopts *io = (inet_srcopts *)ao; |
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230 | unsigned act; |
231 | |
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232 | CONF_BEGIN(sc, "source", "Internet socket source") |
233 | |
234 | /* --- Initialization --- */ |
235 | |
236 | if (!io) { |
237 | if (!inet_globalsrc.acltail) |
238 | inet_globalsrc.acltail = &inet_globalsrc.acl; |
239 | io = &inet_globalsrc; |
240 | } |
241 | |
242 | /* --- Source address configuration --- */ |
243 | |
244 | if (strcmp(sc->d.buf, "addr") == 0) { |
245 | addropt(sc, &io->io); |
246 | CONF_ACCEPT; |
247 | } |
248 | |
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249 | /* --- Access control limitations --- */ |
250 | |
251 | if ((strcmp(sc->d.buf, "allow") == 0 && (act = ACL_ALLOW, 1)) || |
252 | (strcmp(sc->d.buf, "deny") == 0 && (act = ACL_DENY, 1))) { |
253 | struct hostent *h; |
254 | struct netent *n; |
255 | struct in_addr a, m; |
256 | dstr d = DSTR_INIT; |
257 | |
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258 | /* --- Find out what's going on --- */ |
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259 | |
260 | token(sc); |
261 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "from") == 0) |
262 | token(sc); |
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263 | |
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264 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "priv-port") == 0) { |
265 | acl_addpriv(&io->acltail, act); |
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266 | token(sc); |
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267 | } else { |
268 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "host") == 0) |
269 | token(sc); |
270 | |
271 | /* --- Find the host or network address --- */ |
272 | |
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273 | conf_name(sc, '.', &d); |
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274 | #ifdef HAVE_GETNETBYNAME |
275 | if ((n = getnetbyname(d.buf)) != 0) |
276 | a.s_addr = htonl(n->n_net); |
277 | else |
278 | #endif |
279 | if ((h = gethostbyname(d.buf)) == 0) |
280 | error(sc, "couldn't resolve address `%s'", d.buf); |
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281 | else |
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282 | memcpy(&a, h->h_addr, sizeof(struct in_addr)); |
283 | |
284 | /* --- Find the netmask, if any --- */ |
285 | |
286 | if (sc->t != '/') |
287 | m.s_addr = ~0ul; |
288 | else { |
289 | token(sc); |
290 | DRESET(&d); |
291 | conf_name(sc, '.', &d); |
292 | if (strchr(d.buf, '.') == 0) { |
293 | int n = atoi(d.buf); |
294 | if (n == 0) |
295 | m.s_addr = 0; |
296 | else |
297 | m.s_addr = htonl((~0ul << (32 - n)) & 0xffffffff); |
298 | } else { |
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299 | #ifdef HAVE_INET_ATON |
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300 | if (!inet_aton(d.buf, &m)) |
301 | error(sc, "bad netmask `%s'", d.buf); |
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302 | #else |
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303 | m.s_addr = inet_addr(d.buf); |
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304 | #endif |
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305 | } |
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306 | } |
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307 | dstr_destroy(&d); |
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308 | |
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309 | /* --- Add the access control entry --- */ |
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310 | |
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311 | acl_addhost(&io->acltail, act, a, m); |
312 | } |
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313 | CONF_ACCEPT; |
314 | } |
315 | |
316 | /* --- Anything unrecognized --- */ |
317 | |
318 | CONF_END; |
319 | } |
320 | |
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321 | static int targopt(scanner *sc, addr_opts *ao) |
322 | { |
323 | inet_targopts *io = (inet_targopts *)ao; |
324 | |
325 | CONF_BEGIN(sc, "dest", "Internet socket target"); |
326 | if (strcmp(sc->d.buf, "addr") == 0) { |
327 | addropt(sc, &io->io); |
328 | CONF_ACCEPT; |
329 | } |
330 | CONF_END; |
331 | } |
332 | |
333 | static int inet_option(scanner *sc, addr_opts *ao, unsigned type) |
334 | { |
335 | CONF_BEGIN(sc, "inet", "Internet socket"); |
336 | if (type != ADDR_DEST && srcopt(sc, ao)) |
337 | CONF_ACCEPT; |
338 | if (type != ADDR_SRC && targopt(sc, ao)) |
339 | CONF_ACCEPT; |
340 | CONF_END; |
341 | } |
342 | |
343 | /* --- @freeopts@ --- */ |
344 | |
345 | static void inet_freesrcopts(addr_opts *ao) |
346 | { |
347 | inet_srcopts *io = (inet_srcopts *)ao; |
348 | acl_free(io->acl); |
349 | DESTROY(io); |
350 | } |
351 | |
352 | static void inet_freetargopts(addr_opts *ao) |
353 | { |
354 | inet_targopts *io = (inet_targopts *)ao; |
355 | DESTROY(io); |
356 | } |
357 | |
358 | /* --- @bind@ --- */ |
359 | |
360 | static int inet_bind(addr *a, addr_opts *ao) |
361 | { |
362 | inet_addrx *ia = (inet_addrx *)a; |
363 | inet_srcopts *io = (inet_srcopts *)ao; |
364 | struct sockaddr_in sin; |
365 | int opt = 1; |
366 | int fd; |
367 | |
368 | if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) |
369 | goto fail_0; |
370 | setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); |
371 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
372 | sin = ia->sin; |
373 | sin.sin_addr = io->io.bind; |
374 | if (bind(fd, (struct sockaddr *)&sin, sizeof(ia->sin))) |
375 | goto fail_1; |
376 | return (fd); |
377 | |
378 | fail_1: |
379 | close(fd); |
380 | fail_0: |
381 | return (-1); |
382 | } |
383 | |
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384 | /* --- @accept@ --- */ |
385 | |
386 | static reffd *inet_accept(int fd, addr_opts *ao, const char *desc) |
387 | { |
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388 | inet_srcopts *io = (inet_srcopts *)ao; |
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389 | int nfd; |
390 | id_req q; |
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391 | size_t lsinsz = sizeof(q.lsin), rsinsz = sizeof(q.rsin); |
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392 | int act = ACL_ALLOW; |
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393 | |
394 | /* --- Accept the new connection --- */ |
395 | |
396 | if ((nfd = accept(fd, (struct sockaddr *)&q.rsin, &rsinsz)) < 0) |
397 | return (0); |
398 | if (getsockname(nfd, (struct sockaddr *)&q.lsin, &lsinsz)) { |
399 | close(nfd); |
400 | return (0); |
401 | } |
402 | q.desc = desc; |
403 | q.r = reffd_init(nfd); |
404 | |
405 | /* --- Find out whether this connection is allowed --- */ |
406 | |
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407 | if (!acl_check(io->acl, q.rsin.sin_addr, ntohs(q.rsin.sin_port), &act)) |
408 | acl_check(inet_globalsrc.acl, q.rsin.sin_addr, |
409 | ntohs(q.rsin.sin_port), &act); |
410 | if (act != ACL_ALLOW) { |
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411 | q.act = "refused"; |
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412 | if (!(io->io.ao.f & ADDRF_NOLOG)) |
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413 | identify(&q); |
414 | REFFD_DEC(q.r); |
415 | return (0); |
416 | } |
417 | |
418 | /* --- Everything seems to be OK --- */ |
419 | |
420 | q.act = "accepted"; |
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421 | if (!(io->io.ao.f & ADDRF_NOLOG)) |
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422 | identify(&q); |
423 | return (q.r); |
424 | } |
425 | |
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426 | /* --- @connect@ --- */ |
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427 | |
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428 | static int inet_connect(addr *a, addr_opts *ao, conn *c, endpt *e) |
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429 | { |
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430 | inet_addrx *ia = (inet_addrx *)a; |
431 | inet_targopts *io = (inet_targopts *)ao; |
432 | int fd; |
433 | |
434 | if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) |
435 | goto fail_0; |
436 | if (io->io.bind.s_addr != INADDR_ANY) { |
437 | struct sockaddr_in sin; |
438 | memset(&sin, 0, sizeof(sin)); |
439 | sin.sin_family = AF_INET; |
440 | sin.sin_addr = io->io.bind; |
441 | sin.sin_port = 0; |
442 | if (bind(fd, (struct sockaddr *)&sin, sizeof(sin))) |
443 | goto fail_1; |
444 | } |
445 | fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC); |
446 | return (conn_init(c, sel, fd, (struct sockaddr *)&ia->sin, sizeof(ia->sin), |
447 | starget_connected, e)); |
448 | fail_1: |
449 | close(fd); |
450 | fail_0: |
451 | return (-1); |
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452 | } |
453 | |
454 | /* --- Ops table --- */ |
455 | |
456 | addr_ops inet_ops = { |
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457 | "inet", |
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458 | inet_read, inet_destroy, inet_print, |
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459 | inet_initsrcopts, inet_option, inet_freesrcopts, |
460 | inet_bind, 0, inet_accept, |
461 | inet_inittargopts, inet_freetargopts, |
462 | inet_connect |
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463 | }; |
464 | |
465 | /*----- That's all, folks -------------------------------------------------*/ |