3 * Background reverse name resolution (ADNS version)
5 * (c) 2003 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of the mLib utilities library.
12 * mLib is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * mLib 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 Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with mLib; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 * HOWEVER, since GNU adns is covered by the full GNU General Public
29 * License, this file (only) is also covered by the full GNU GPL, and
30 * you may NOT take advantage of the more liberal conditions of the
31 * LGPL when modifying or redistributing this file. This doesn't mean
32 * that a program which uses the interface provided by this file is
33 * covered by the GPL, since @bres.c@ provides the same interface and
34 * is LGPL. However, it does mean that if your program depends, for
35 * some reason (e.g., to meet particular performance criteria), on
36 * this adns-based implementation of mLib's background resolver then it
37 * must be licensed under the full GPL.
43 # error "You need the ADNS library to compile this file."
46 /*----- Header files ------------------------------------------------------*/
55 #include <sys/types.h>
60 #include <sys/socket.h>
61 #include <netinet/in.h>
62 #include <arpa/inet.h>
73 /*----- Static variables --------------------------------------------------*/
75 static adns_state ads
;
76 static sel_state
*sel
;
77 static sel_hook selhook
;
79 /*----- Main code ---------------------------------------------------------*/
81 /* --- @bres_abort@ --- *
83 * Arguments: @bres_client *rc@ = pointer to client block
87 * Use: Removes a queued job.
90 void bres_abort(bres_client
*rc
)
92 if (rc
->q
== adns_r_addr
) xfree(rc
->u
.name
);
93 if (rc
->a
) free(rc
->a
);
97 /* --- @bres_byaddr@ --- *
99 * Arguments: @bres_client *rc@ = pointer to client block
100 * @struct in_addr addr@ = address to resolve
101 * @void (*func)(struct hostent *h, void *p)@ = handler function
102 * @void *p@ = argument for handler function
106 * Use: Adds an address lookup job to the queue. The job will be
107 * processed when there's a spare resolver process to deal with
111 void bres_byaddr(bres_client
*rc
, struct in_addr addr
,
112 void (*func
)(struct hostent */
*h*/
, void */
*p*/
),
116 struct sockaddr_in sin
;
119 sin
.sin_family
= AF_INET
;
122 if ((e
= adns_submit_reverse(ads
, (struct sockaddr
*)&sin
, adns_r_ptr
,
123 0, rc
, &rc
->aq
)) != 0)
136 /* --- @bres_byname@ --- *
138 * Arguments: @bres_client *rc@ = pointer to client block
139 * @const char *name@ = name to resolve
140 * @void (*func)(struct hostent *h, void *p)@ = handler function
141 * @void *p@ = argument for handler function
145 * Use: Adds a name lookup job to the queue. The job will be
146 * processed when there's a spare resolver process to deal with
150 void bres_byname(bres_client
*rc
, const char *name
,
151 void (*func
)(struct hostent */
*h*/
, void */
*p*/
),
157 if ((e
= adns_submit(ads
, name
, adns_r_addr
,
158 adns_qf_search
| adns_qf_owner
, rc
, &rc
->aq
)) != 0)
162 rc
->u
.name
= xstrdup(name
);
171 /* --- @bres_exec@ --- *
173 * Arguments: @const char *file@ = file containing server code or null
177 * Use: Makes `bres' use a standalone server rather than copies of
178 * the current process. This can reduce memory consumption for
179 * large processes, at the expense of startup time (which
180 * shouldn't be too bad anyway, because of the resolver design).
181 * If the filename is null, a default set up at install time is
182 * used. It's probably a good idea to leave it alone.
185 void bres_exec(const char *file
)
190 /* --- @report@ --- *
192 * Arguments: @bres_client *c@ = client descriptor block
193 * @adns_answer *a@ = A-record answer from resolver library
194 * @adns_rr_addr *av@ = vector of address records
195 * @int an@ = number of address records (must be positive)
196 * @char **nv@ = vector of name strings
197 * @int nn@ = number of name strings (must be positive)
201 * Use: Formats the given answer into a @struct hostent@ and reports
202 * it to the waiting client application.
205 static void report(bres_client
*rc
, adns_answer
*a
,
206 adns_rr_addr
*av
, int an
,
215 if (a
->cname
) n
[j
++] = a
->cname
;
216 else { n
[j
++] = *nv
; nv
++; nn
--; }
217 for (i
= 0; i
< nn
&& j
< N(n
) - 1; i
++)
218 if (strcmp(n
[0], nv
[i
]) != 0) n
[j
++] = nv
[i
];
220 for (i
= j
= 0; i
< an
&& j
< N(av
) - 1; i
++) {
221 if (av
[i
].addr
.sa
.sa_family
== AF_INET
)
222 aa
[j
++] = (char *)&av
[i
].addr
.inet
.sin_addr
;
227 h
.h_addrtype
= AF_INET
;
228 h
.h_length
= sizeof(struct in_addr
);
233 /* --- @beforehook@, @afterhook@ --- *
235 * Arguments: @sel_state *s@ = select state
236 * @sel_args *sa@ = argument block
237 * @void *p@ = uninteresting pointer
241 * Use: Processes the selector's arguments before @select@ is
242 * called, to allow ADNS to do its thing.
245 static void beforehook(sel_state
*s
, sel_args
*sa
, void *p
)
247 adns_beforeselect(ads
, &sa
->maxfd
,
248 &sa
->fd
[SEL_READ
], &sa
->fd
[SEL_WRITE
], &sa
->fd
[SEL_EXC
],
249 &sa
->tvp
, &sa
->tv
, &sa
->now
);
252 static void afterhook(sel_state
*s
, sel_args
*sa
, void *p
)
261 adns_afterselect(ads
, sa
->maxfd
,
262 &sa
->fd
[SEL_READ
], &sa
->fd
[SEL_WRITE
], &sa
->fd
[SEL_EXC
],
264 while (q
= 0, (e
= adns_check(ads
, &q
, &a
, &c
)) == 0) {
268 else switch (rc
->q
) {
270 assert(a
->type
== adns_r_addr
);
272 report(rc
, a
, a
->rrs
.addr
, a
->nrrs
, &a
->owner
, 1);
276 if (a
->type
== adns_r_ptr
) {
278 if ((e
= adns_submit(ads
, a
->rrs
.str
[0], adns_r_addr
,
283 assert(a
->type
== adns_r_addr
);
284 for (i
= 0; i
< a
->nrrs
; i
++) {
285 if (a
->rrs
.addr
[i
].addr
.sa
.sa_family
== AF_INET
&&
286 a
->rrs
.addr
[i
].addr
.inet
.sin_addr
.s_addr
==
293 report(rc
, a
, &a
->rrs
.addr
[i
], 1, aa
->rrs
.str
, aa
->nrrs
);
304 if (rc
->q
== adns_r_addr
) xfree(rc
->u
.name
);
305 if (rc
->a
) free(rc
->a
);
311 /* --- @bres_init@ --- *
313 * Arguments: @sel_state *s@ = pointer to select multiplexor
317 * Use: Initializes the background resolver for use.
320 void bres_init(sel_state
*s
)
324 if ((e
= adns_init(&ads
, adns_if_noautosys
, 0)) != 0) {
325 moan("adns_init failed: resolver won't work");
328 sel_addhook(s
, &selhook
, beforehook
, afterhook
, 0);
332 /*----- That's all, folks -------------------------------------------------*/