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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: inet.c,v 1.3 2000/08/01 17:59:56 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 1.3 2000/08/01 17:59:56 mdw |
33 | * Switch over to using `size_t' for socket address lengths. |
34 | * |
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35 | * Revision 1.2 1999/07/27 18:30:53 mdw |
36 | * Various minor portability fixes. |
37 | * |
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38 | * Revision 1.1 1999/07/26 23:34:11 mdw |
39 | * New socket address types. |
40 | * |
41 | */ |
42 | |
43 | /*----- Header files ------------------------------------------------------*/ |
44 | |
45 | #include "config.h" |
46 | |
47 | #include <ctype.h> |
48 | #include <errno.h> |
49 | #include <stdio.h> |
50 | #include <stdlib.h> |
51 | #include <string.h> |
52 | |
53 | #include <sys/types.h> |
54 | #include <unistd.h> |
55 | |
56 | #include <sys/socket.h> |
57 | #include <netinet/in.h> |
58 | #include <arpa/inet.h> |
59 | #include <netdb.h> |
60 | |
61 | #include <mLib/alloc.h> |
62 | #include <mLib/dstr.h> |
63 | #include <mLib/report.h> |
64 | #include <mLib/sub.h> |
65 | |
66 | #include "acl.h" |
67 | #include "addr.h" |
68 | #include "conf.h" |
69 | #include "identify.h" |
70 | #include "inet.h" |
71 | #include "reffd.h" |
72 | #include "scan.h" |
73 | |
74 | /*----- Data structures ---------------------------------------------------*/ |
75 | |
76 | typedef struct inet_addrx { |
77 | addr a; |
78 | struct sockaddr_in sin; |
79 | } inet_addrx; |
80 | |
81 | typedef struct inet_opts { |
82 | addr_opts ao; |
83 | acl_entry *acl; |
84 | acl_entry **acltail; |
85 | } inet_opts; |
86 | |
87 | /*----- Protocol operations -----------------------------------------------*/ |
88 | |
89 | /* --- @read@ --- */ |
90 | |
91 | static addr *inet_read(scanner *sc, unsigned type) |
92 | { |
93 | inet_addrx *ia = xmalloc(sizeof(*ia)); |
94 | |
95 | ia->a.ops = &inet_ops; |
96 | ia->a.sz = sizeof(struct sockaddr_in); |
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97 | memset(&ia->sin, 0, sizeof(ia->sin)); |
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98 | ia->sin.sin_family = AF_INET; |
99 | |
100 | /* --- Read the host address part --- */ |
101 | |
102 | switch (type) { |
103 | case ADDR_SRC: |
104 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "port") == 0) |
105 | token(sc); |
106 | ia->sin.sin_addr.s_addr = htonl(INADDR_ANY); |
107 | break; |
108 | case ADDR_DEST: { |
109 | struct hostent *h; |
110 | dstr d = DSTR_INIT; |
111 | conf_name(sc, '.', &d); |
112 | if ((h = gethostbyname(d.buf)) == 0) |
113 | error(sc, "couldn't resolve Internet address `%s'", d.buf); |
114 | memcpy(&ia->sin.sin_addr, h->h_addr, sizeof(struct in_addr)); |
115 | dstr_destroy(&d); |
116 | if (sc->t == ':') |
117 | token(sc); |
118 | } break; |
119 | } |
120 | |
121 | /* --- Read the port number --- */ |
122 | |
123 | { |
124 | struct servent *s; |
125 | |
126 | if (sc->t != CTOK_WORD) |
127 | error(sc, "parse error, TCP port expected"); |
128 | if (isdigit((unsigned char)sc->d.buf[0])) |
129 | ia->sin.sin_port = htons(atoi(sc->d.buf)); |
130 | else if ((s = getservbyname(sc->d.buf, "tcp")) == 0) |
131 | error(sc, "unknown tcp service `%s'", sc->d.buf); |
132 | else |
133 | ia->sin.sin_port = s->s_port; |
134 | token(sc); |
135 | } |
136 | |
137 | return (&ia->a); |
138 | } |
139 | |
140 | /* --- @destroy@ --- */ |
141 | |
142 | static void inet_destroy(addr *a) |
143 | { |
144 | inet_addrx *ia = (inet_addrx *)a; |
145 | DESTROY(ia); |
146 | } |
147 | |
148 | /* --- @print@ --- */ |
149 | |
150 | static void inet_print(addr *a, unsigned type, dstr *d) |
151 | { |
152 | inet_addrx *ia = (inet_addrx *)a; |
153 | switch (type) { |
154 | case ADDR_SRC: |
155 | dstr_putf(d, "inet:%u", (unsigned)ntohs(ia->sin.sin_port)); |
156 | break; |
157 | case ADDR_DEST: |
158 | dstr_putf(d, "inet:%s:%u", |
159 | inet_ntoa(ia->sin.sin_addr), |
160 | (unsigned)ntohs(ia->sin.sin_port)); |
161 | break; |
162 | } |
163 | } |
164 | |
165 | /* --- @initopts@ --- */ |
166 | |
167 | static addr_opts *inet_initopts(void) |
168 | { |
169 | inet_opts *io = CREATE(inet_opts); |
170 | io->acl = 0; |
171 | io->acltail = &io->acl; |
172 | return (&io->ao); |
173 | } |
174 | |
175 | /* --- @option@ --- */ |
176 | |
177 | static int inet_option(scanner *sc, addr_opts *ao) |
178 | { |
179 | inet_opts *io = (inet_opts *)ao; |
180 | |
181 | CONF_BEGIN(sc, "inet", "Internet socket") |
182 | |
183 | unsigned act; |
184 | |
185 | /* --- Access control limitations --- */ |
186 | |
187 | if ((strcmp(sc->d.buf, "allow") == 0 && (act = ACL_ALLOW, 1)) || |
188 | (strcmp(sc->d.buf, "deny") == 0 && (act = ACL_DENY, 1))) { |
189 | struct hostent *h; |
190 | struct netent *n; |
191 | struct in_addr a, m; |
192 | dstr d = DSTR_INIT; |
193 | |
194 | /* --- Find the host or network address --- */ |
195 | |
196 | token(sc); |
197 | if (sc->t == CTOK_WORD && strcmp(sc->d.buf, "from") == 0) |
198 | token(sc); |
199 | conf_name(sc, '.', &d); |
200 | if ((n = getnetbyname(d.buf)) != 0) |
201 | a.s_addr = htonl(n->n_net); |
202 | else if ((h = gethostbyname(d.buf)) == 0) |
203 | error(sc, "couldn't resolve address `%s'", d.buf); |
204 | else |
205 | memcpy(&a, h->h_addr, sizeof(struct in_addr)); |
206 | |
207 | /* --- Find the netmask, if any --- */ |
208 | |
209 | if (sc->t != '/') |
210 | m.s_addr = ~0ul; |
211 | else { |
212 | token(sc); |
213 | DRESET(&d); |
214 | conf_name(sc, '.', &d); |
215 | if (strchr(d.buf, '.') == 0) { |
216 | int n = atoi(d.buf); |
217 | if (n == 0) |
218 | m.s_addr = 0; |
219 | else |
220 | m.s_addr = htonl((~0ul << (32 - n)) & 0xffffffff); |
221 | } else { |
222 | #ifdef HAVE_INET_ATON |
223 | if (!inet_aton(d.buf, &m)) |
224 | error(sc, "bad netmask `%s'", d.buf); |
225 | #else |
226 | m.s_addr = inet_addr(d.buf); |
227 | #endif |
228 | } |
229 | } |
230 | dstr_destroy(&d); |
231 | |
232 | /* --- Add the access control entry --- */ |
233 | |
234 | acl_add(io ? &io->acltail : 0, act, a, m); |
235 | CONF_ACCEPT; |
236 | } |
237 | |
238 | /* --- Anything unrecognized --- */ |
239 | |
240 | CONF_END; |
241 | } |
242 | |
243 | /* --- @accept@ --- */ |
244 | |
245 | static reffd *inet_accept(int fd, addr_opts *ao, const char *desc) |
246 | { |
247 | inet_opts *io = (inet_opts *)ao; |
248 | int nfd; |
249 | id_req q; |
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250 | size_t lsinsz = sizeof(q.lsin), rsinsz = sizeof(q.rsin); |
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251 | |
252 | /* --- Accept the new connection --- */ |
253 | |
254 | if ((nfd = accept(fd, (struct sockaddr *)&q.rsin, &rsinsz)) < 0) |
255 | return (0); |
256 | if (getsockname(nfd, (struct sockaddr *)&q.lsin, &lsinsz)) { |
257 | close(nfd); |
258 | return (0); |
259 | } |
260 | q.desc = desc; |
261 | q.r = reffd_init(nfd); |
262 | |
263 | /* --- Find out whether this connection is allowed --- */ |
264 | |
265 | if (!acl_check(io->acl, q.rsin.sin_addr)) { |
266 | q.act = "refused"; |
267 | if (!(io->ao.f & ADDRF_NOLOG)) |
268 | identify(&q); |
269 | REFFD_DEC(q.r); |
270 | return (0); |
271 | } |
272 | |
273 | /* --- Everything seems to be OK --- */ |
274 | |
275 | q.act = "accepted"; |
276 | if (!(io->ao.f & ADDRF_NOLOG)) |
277 | identify(&q); |
278 | return (q.r); |
279 | } |
280 | |
281 | /* --- @freeopts@ --- */ |
282 | |
283 | static void inet_freeopts(addr_opts *ao) |
284 | { |
285 | inet_opts *io = (inet_opts *)ao; |
286 | acl_free(io->acl); |
287 | DESTROY(ao); |
288 | } |
289 | |
290 | /* --- Ops table --- */ |
291 | |
292 | addr_ops inet_ops = { |
293 | "inet", PF_INET, |
294 | inet_read, inet_destroy, inet_print, |
295 | inet_initopts, inet_option, inet_accept, inet_freeopts, 0, 0 |
296 | }; |
297 | |
298 | /*----- That's all, folks -------------------------------------------------*/ |