3 * $Id: bres-adns.c,v 1.1 2003/12/13 20:37:59 mdw Exp $
5 * Background reverse name resolution (ADNS version)
7 * (c) 2003 Straylight/Edgeware
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of the mLib utilities library.
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.
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.
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,
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.
42 /*----- Revision history --------------------------------------------------*
44 * $Log: bres-adns.c,v $
45 * Revision 1.1 2003/12/13 20:37:59 mdw
46 * Add adns support in background resolver.
51 # error "You need the ADNS library to compile this file."
54 /*----- Header files ------------------------------------------------------*/
63 #include <sys/types.h>
68 #include <sys/socket.h>
69 #include <netinet/in.h>
70 #include <arpa/inet.h>
81 /*----- Static variables --------------------------------------------------*/
83 static adns_state ads;
84 static sel_state *sel;
85 static sel_hook selhook;
87 /*----- Main code ---------------------------------------------------------*/
89 /* --- @bres_abort@ --- *
91 * Arguments: @bres_client *rc@ = pointer to client block
95 * Use: Removes a queued job.
98 void bres_abort(bres_client *rc)
100 if (rc->q == adns_r_addr) xfree(rc->u.name);
101 if (rc->a) free(rc->a);
105 /* --- @bres_byaddr@ --- *
107 * Arguments: @bres_client *rc@ = pointer to client block
108 * @struct in_addr addr@ = address to resolve
109 * @void (*func)(struct hostent *h, void *p)@ = handler function
110 * @void *p@ = argument for handler function
114 * Use: Adds an address lookup job to the queue. The job will be
115 * processed when there's a spare resolver process to deal with
119 void bres_byaddr(bres_client *rc, struct in_addr addr,
120 void (*func)(struct hostent */*h*/, void */*p*/),
124 struct sockaddr_in sin;
127 sin.sin_family = AF_INET;
130 if ((e = adns_submit_reverse(ads, (struct sockaddr *)&sin, adns_r_ptr,
131 0, rc, &rc->aq)) != 0)
144 /* --- @bres_byname@ --- *
146 * Arguments: @bres_client *rc@ = pointer to client block
147 * @const char *name@ = name to resolve
148 * @void (*func)(struct hostent *h, void *p)@ = handler function
149 * @void *p@ = argument for handler function
153 * Use: Adds a name lookup job to the queue. The job will be
154 * processed when there's a spare resolver process to deal with
158 void bres_byname(bres_client *rc, const char *name,
159 void (*func)(struct hostent */*h*/, void */*p*/),
165 if ((e = adns_submit(ads, name, adns_r_addr,
166 adns_qf_search, rc, &rc->aq)) != 0)
170 rc->u.name = xstrdup(name);
179 /* --- @bres_exec@ --- *
181 * Arguments: @const char *file@ = file containing server code or null
185 * Use: Makes `bres' use a standalone server rather than copies of
186 * the current process. This can reduce memory consumption for
187 * large processes, at the expense of startup time (which
188 * shouldn't be too bad anyway, because of the resolver design).
189 * If the filename is null, a default set up at install time is
190 * used. It's probably a good idea to leave it alone.
193 void bres_exec(const char *file)
198 /* --- @report@ --- *
200 * Arguments: @bres_client *c@ = client descriptor block
201 * @adns_answer *a@ = A-record answer from resolver library
202 * @adns_rr_addr *av@ = vector of address records
203 * @int an@ = number of address records (must be positive)
204 * @char **nv@ = vector of name strings
205 * @int nn@ = number of name strings (must be positive)
209 * Use: Formats the given answer into a @struct hostent@ and reports
210 * it to the waiting client application.
213 static void report(bres_client *rc, adns_answer *a,
214 adns_rr_addr *av, int an,
223 if (a->cname) n[j++] = a->cname;
224 else { n[j++] = *nv; nv++; nn--; }
225 for (i = 0; i < nn && j < N(n) - 1; i++)
226 if (strcmp(n[0], nv[i]) != 0) n[j++] = nv[i];
228 for (i = j = 0; i < an && j < N(av) - 1; i++) {
229 if (av[i].addr.sa.sa_family == AF_INET)
230 aa[j++] = (char *)&av[i].addr.inet.sin_addr;
235 h.h_addrtype = AF_INET;
236 h.h_length = sizeof(struct in_addr);
241 /* --- @beforehook@, @afterhook@ --- *
243 * Arguments: @sel_state *s@ = select state
244 * @sel_args *sa@ = argument block
245 * @void *p@ = uninteresting pointer
249 * Use: Processes the selector's arguments before @select@ is
250 * called, to allow ADNS to do its thing.
253 static void beforehook(sel_state *s, sel_args *sa, void *p)
255 adns_beforeselect(ads, &sa->maxfd,
256 &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
257 &sa->tvp, &sa->tv, &sa->now);
260 static void afterhook(sel_state *s, sel_args *sa, void *p)
269 adns_afterselect(ads, sa->maxfd,
270 &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
272 while (q = 0, (e = adns_check(ads, &q, &a, &c)) == 0) {
276 else switch (rc->q) {
278 assert(a->type == adns_r_addr);
279 report(rc, a, a->rrs.addr, a->nrrs, &rc->u.name, 1);
284 if (a->type == adns_r_ptr) {
286 if ((e = adns_submit(ads, a->rrs.str[0], adns_r_addr,
291 assert(a->type == adns_r_addr);
292 for (i = 0; i < a->nrrs; i++) {
293 if (a->rrs.addr[i].addr.sa.sa_family == AF_INET &&
294 a->rrs.addr[i].addr.inet.sin_addr.s_addr ==
300 report(rc, a, &a->rrs.addr[i], 1, rc->a->rrs.str, rc->a->nrrs);
312 if (rc->q == adns_r_addr) xfree(rc->u.name);
313 if (rc->a) free(rc->a);
318 /* --- @bres_init@ --- *
320 * Arguments: @sel_state *s@ = pointer to select multiplexor
324 * Use: Initializes the background resolver for use.
327 void bres_init(sel_state *s)
331 if ((e = adns_init(&ads, 0, 0)) != 0) {
332 moan("adns_init failed: resolver won't work");
335 sel_addhook(s, &selhook, beforehook, afterhook, 0);
339 /*----- That's all, folks -------------------------------------------------*/