chiark / gitweb /
Add global unihash table; use universal hashing instead of CRC.
[mLib] / bres-adns.c
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14d7100d 1/* -*-c-*-
2 *
4f6d400b 3 * $Id: bres-adns.c,v 1.2 2003/12/14 14:46:38 mdw Exp $
14d7100d 4 *
5 * Background reverse name resolution (ADNS version)
6 *
7 * (c) 2003 Straylight/Edgeware
8 */
9
10/*----- Licensing notice --------------------------------------------------*
11 *
12 * This file is part of the mLib utilities library.
13 *
14 * mLib is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU Library General Public License as
16 * published by the Free Software Foundation; either version 2 of the
17 * License, or (at your option) any later version.
18 *
19 * mLib 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 Library General Public License for more details.
23 *
24 * You should have received a copy of the GNU Library General Public
25 * License along with mLib; if not, write to the Free
26 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
27 * MA 02111-1307, USA.
28 *
29 *
30 * HOWEVER, since GNU adns is covered by the full GNU General Public
31 * License, this file (only) is also covered by the full GNU GPL, and
32 * you may NOT take advantage of the more liberal conditions of the
33 * LGPL when modifying or redistributing this file. This doesn't mean
34 * that a program which uses the interface provided by this file is
35 * covered by the GPL, since @bres.c@ provides the same interface and
36 * is LGPL. However, it does mean that if your program depends, for
37 * some reason (e.g., to meet particular performance criteria), on
38 * this adns-based implementation of mLib's background resolver then it
39 * must be licensed under the full GPL.
40 */
41
42/*----- Revision history --------------------------------------------------*
43 *
44 * $Log: bres-adns.c,v $
4f6d400b 45 * Revision 1.2 2003/12/14 14:46:38 mdw
46 * Qualify name given to @bres_byname@.
47 *
14d7100d 48 * Revision 1.1 2003/12/13 20:37:59 mdw
49 * Add adns support in background resolver.
50 *
51 */
52
53#ifndef HAVE_ADNS
54# error "You need the ADNS library to compile this file."
55#endif
56
57/*----- Header files ------------------------------------------------------*/
58
59#include <assert.h>
60#include <errno.h>
61#include <signal.h>
62#include <stdio.h>
63#include <stdlib.h>
64#include <string.h>
65
66#include <sys/types.h>
67#include <sys/time.h>
68#include <unistd.h>
69#include <sys/wait.h>
70
71#include <sys/socket.h>
72#include <netinet/in.h>
73#include <arpa/inet.h>
74#include <netdb.h>
75
76#include <adns.h>
77
78#include "alloc.h"
79#include "bres.h"
80#include "macros.h"
81#include "report.h"
82#include "sel.h"
83
84/*----- Static variables --------------------------------------------------*/
85
86static adns_state ads;
87static sel_state *sel;
88static sel_hook selhook;
89
90/*----- Main code ---------------------------------------------------------*/
91
92/* --- @bres_abort@ --- *
93 *
94 * Arguments: @bres_client *rc@ = pointer to client block
95 *
96 * Returns: ---
97 *
98 * Use: Removes a queued job.
99 */
100
101void bres_abort(bres_client *rc)
102{
103 if (rc->q == adns_r_addr) xfree(rc->u.name);
104 if (rc->a) free(rc->a);
105 adns_cancel(rc->aq);
106}
107
108/* --- @bres_byaddr@ --- *
109 *
110 * Arguments: @bres_client *rc@ = pointer to client block
111 * @struct in_addr addr@ = address to resolve
112 * @void (*func)(struct hostent *h, void *p)@ = handler function
113 * @void *p@ = argument for handler function
114 *
115 * Returns: ---
116 *
117 * Use: Adds an address lookup job to the queue. The job will be
118 * processed when there's a spare resolver process to deal with
119 * it.
120 */
121
122void bres_byaddr(bres_client *rc, struct in_addr addr,
123 void (*func)(struct hostent */*h*/, void */*p*/),
124 void *p)
125{
126 int e;
127 struct sockaddr_in sin;
128
129 if (!ads) goto fail;
130 sin.sin_family = AF_INET;
131 sin.sin_addr = addr;
132 sin.sin_port = 0;
133 if ((e = adns_submit_reverse(ads, (struct sockaddr *)&sin, adns_r_ptr,
134 0, rc, &rc->aq)) != 0)
135 goto fail;
136 rc->a = 0;
137 rc->q = adns_r_ptr;
138 rc->u.addr = addr;
139 rc->func = func;
140 rc->p = p;
141 return;
142
143fail:
144 func(0, p);
145}
146
147/* --- @bres_byname@ --- *
148 *
149 * Arguments: @bres_client *rc@ = pointer to client block
150 * @const char *name@ = name to resolve
151 * @void (*func)(struct hostent *h, void *p)@ = handler function
152 * @void *p@ = argument for handler function
153 *
154 * Returns: ---
155 *
156 * Use: Adds a name lookup job to the queue. The job will be
157 * processed when there's a spare resolver process to deal with
158 * it.
159 */
160
161void bres_byname(bres_client *rc, const char *name,
162 void (*func)(struct hostent */*h*/, void */*p*/),
163 void *p)
164{
165 int e;
166
167 if (!ads) goto fail;
168 if ((e = adns_submit(ads, name, adns_r_addr,
4f6d400b 169 adns_qf_search | adns_qf_owner, rc, &rc->aq)) != 0)
14d7100d 170 goto fail;
171 rc->a = 0;
172 rc->q = adns_r_addr;
173 rc->u.name = xstrdup(name);
174 rc->func = func;
175 rc->p = p;
176 return;
177
178fail:
179 func(0, p);
180}
181
182/* --- @bres_exec@ --- *
183 *
184 * Arguments: @const char *file@ = file containing server code or null
185 *
186 * Returns: ---
187 *
188 * Use: Makes `bres' use a standalone server rather than copies of
189 * the current process. This can reduce memory consumption for
190 * large processes, at the expense of startup time (which
191 * shouldn't be too bad anyway, because of the resolver design).
192 * If the filename is null, a default set up at install time is
193 * used. It's probably a good idea to leave it alone.
194 */
195
196void bres_exec(const char *file)
197{
198 /* Nothin' doin' */
199}
200
201/* --- @report@ --- *
202 *
203 * Arguments: @bres_client *c@ = client descriptor block
204 * @adns_answer *a@ = A-record answer from resolver library
205 * @adns_rr_addr *av@ = vector of address records
206 * @int an@ = number of address records (must be positive)
207 * @char **nv@ = vector of name strings
208 * @int nn@ = number of name strings (must be positive)
209 *
210 * Returns: ---
211 *
212 * Use: Formats the given answer into a @struct hostent@ and reports
213 * it to the waiting client application.
214 */
215
216static void report(bres_client *rc, adns_answer *a,
217 adns_rr_addr *av, int an,
218 char **nv, int nn)
219{
220 struct hostent h;
221 char *n[16];
222 char *aa[16];
223 int i, j;
224
225 j = 0;
226 if (a->cname) n[j++] = a->cname;
227 else { n[j++] = *nv; nv++; nn--; }
228 for (i = 0; i < nn && j < N(n) - 1; i++)
229 if (strcmp(n[0], nv[i]) != 0) n[j++] = nv[i];
230 n[j++] = 0;
231 for (i = j = 0; i < an && j < N(av) - 1; i++) {
232 if (av[i].addr.sa.sa_family == AF_INET)
233 aa[j++] = (char *)&av[i].addr.inet.sin_addr;
234 }
235 aa[j++] = 0;
236 h.h_name = n[0];
237 h.h_aliases = n + 1;
238 h.h_addrtype = AF_INET;
239 h.h_length = sizeof(struct in_addr);
240 h.h_addr_list = aa;
241 rc->func(&h, rc->p);
242}
243
244/* --- @beforehook@, @afterhook@ --- *
245 *
246 * Arguments: @sel_state *s@ = select state
247 * @sel_args *sa@ = argument block
248 * @void *p@ = uninteresting pointer
249 *
250 * Returns: ---
251 *
252 * Use: Processes the selector's arguments before @select@ is
253 * called, to allow ADNS to do its thing.
254 */
255
256static void beforehook(sel_state *s, sel_args *sa, void *p)
257{
258 adns_beforeselect(ads, &sa->maxfd,
259 &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
260 &sa->tvp, &sa->tv, &sa->now);
261}
262
263static void afterhook(sel_state *s, sel_args *sa, void *p)
264{
265 void *c;
266 bres_client *rc;
267 adns_query q;
268 adns_answer *a;
269 int e;
270 int i;
271
272 adns_afterselect(ads, sa->maxfd,
273 &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
274 &sa->now);
275 while (q = 0, (e = adns_check(ads, &q, &a, &c)) == 0) {
276 rc = c;
277 if (a->status != 0)
278 goto fail;
279 else switch (rc->q) {
280 case adns_r_addr:
281 assert(a->type == adns_r_addr);
4f6d400b 282 report(rc, a, a->rrs.addr, a->nrrs, &a->owner, 1);
14d7100d 283 free(rc->u.name);
284 free(a);
285 break;
286 case adns_r_ptr:
287 if (a->type == adns_r_ptr) {
288 rc->a = a;
289 if ((e = adns_submit(ads, a->rrs.str[0], adns_r_addr,
290 0, rc, &q)) != 0)
291 goto fail;
292 rc->aq = q;
293 } else {
294 assert(a->type == adns_r_addr);
295 for (i = 0; i < a->nrrs; i++) {
296 if (a->rrs.addr[i].addr.sa.sa_family == AF_INET &&
297 a->rrs.addr[i].addr.inet.sin_addr.s_addr ==
298 rc->u.addr.s_addr)
299 goto match;
300 }
301 goto fail;
302 match:
303 report(rc, a, &a->rrs.addr[i], 1, rc->a->rrs.str, rc->a->nrrs);
304 free(rc->a);
305 free(a);
306 }
307 break;
308 default:
309 abort();
310 }
311 continue;
312
313 fail:
314 rc->func(0, rc->p);
315 if (rc->q == adns_r_addr) xfree(rc->u.name);
316 if (rc->a) free(rc->a);
317 free(a);
318 }
319}
320
321/* --- @bres_init@ --- *
322 *
323 * Arguments: @sel_state *s@ = pointer to select multiplexor
324 *
325 * Returns: ---
326 *
327 * Use: Initializes the background resolver for use.
328 */
329
330void bres_init(sel_state *s)
331{
332 int e;
333
334 if ((e = adns_init(&ads, 0, 0)) != 0) {
335 moan("adns_init failed: resolver won't work");
336 return;
337 }
338 sel_addhook(s, &selhook, beforehook, afterhook, 0);
339 sel = s;
340}
341
342/*----- That's all, folks -------------------------------------------------*/