[mLib] / bres-adns.c

/* -*-c-*-
 *
 * $Id$
 *
 * Background reverse name resolution (ADNS version)
 *
 * (c) 2003 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------* 
 *
 * This file is part of the mLib utilities library.
 *
 * mLib is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * 
 * mLib is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with mLib; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 *
 *
 * HOWEVER, since GNU adns is covered by the full GNU General Public
 * License, this file (only) is also covered by the full GNU GPL, and
 * you may NOT take advantage of the more liberal conditions of the
 * LGPL when modifying or redistributing this file.  This doesn't mean
 * that a program which uses the interface provided by this file is
 * covered by the GPL, since @bres.c@ provides the same interface and
 * is LGPL.  However, it does mean that if your program depends, for
 * some reason (e.g., to meet particular performance criteria), on
 * this adns-based implementation of mLib's background resolver then it
 * must be licensed under the full GPL.
 */

#ifndef HAVE_ADNS
#  error "You need the ADNS library to compile this file."
#endif

/*----- Header files ------------------------------------------------------*/

#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <sys/wait.h>

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>

#include <adns.h>

#include "alloc.h"
#include "bres.h"
#include "macros.h"
#include "report.h"
#include "sel.h"

/*----- Static variables --------------------------------------------------*/

static adns_state ads;
static sel_state *sel;
static sel_hook selhook;

/*----- Main code ---------------------------------------------------------*/

/* --- @bres_abort@ --- *
 *
 * Arguments:	@bres_client *rc@ = pointer to client block
 *
 * Returns:	---
 *
 * Use:		Removes a queued job.
 */

void bres_abort(bres_client *rc)
{
  if (rc->q == adns_r_addr) xfree(rc->u.name);
  if (rc->a) free(rc->a);
  adns_cancel(rc->aq);
}

/* --- @bres_byaddr@ --- *
 *
 * Arguments:	@bres_client *rc@ = pointer to client block
 *		@struct in_addr addr@ = address to resolve
 *		@void (*func)(struct hostent *h, void *p)@ = handler function
 *		@void *p@ = argument for handler function
 *
 * Returns:	---
 *
 * Use:		Adds an address lookup job to the queue.  The job will be
 *		processed when there's a spare resolver process to deal with
 *		it.
 */

void bres_byaddr(bres_client *rc, struct in_addr addr,
		 void (*func)(struct hostent */*h*/, void */*p*/),
		 void *p)
{
  int e;
  struct sockaddr_in sin;

  if (!ads) goto fail;
  sin.sin_family = AF_INET;
  sin.sin_addr = addr;
  sin.sin_port = 0;
  if ((e = adns_submit_reverse(ads, (struct sockaddr *)&sin, adns_r_ptr,
			       0, rc, &rc->aq)) != 0)
    goto fail;
  rc->a = 0;
  rc->q = adns_r_ptr;
  rc->u.addr = addr;
  rc->func = func;
  rc->p = p;
  return;

fail:
  func(0, p);
}

/* --- @bres_byname@ --- *
 *
 * Arguments:	@bres_client *rc@ = pointer to client block
 *		@const char *name@ = name to resolve
 *		@void (*func)(struct hostent *h, void *p)@ = handler function
 *		@void *p@ = argument for handler function
 *
 * Returns:	---
 *
 * Use:		Adds a name lookup job to the queue.  The job will be
 *		processed when there's a spare resolver process to deal with
 *		it.
 */

void bres_byname(bres_client *rc, const char *name,
		 void (*func)(struct hostent */*h*/, void */*p*/),
		 void *p)
{
  int e;

  if (!ads) goto fail;
  if ((e = adns_submit(ads, name, adns_r_addr,
		       adns_qf_search | adns_qf_owner, rc, &rc->aq)) != 0)
    goto fail;
  rc->a = 0;
  rc->q = adns_r_addr;
  rc->u.name = xstrdup(name);
  rc->func = func;
  rc->p = p;
  return;

fail:
  func(0, p);
}

/* --- @bres_exec@ --- *
 *
 * Arguments:	@const char *file@ = file containing server code or null
 *
 * Returns:	---
 *
 * Use:		Makes `bres' use a standalone server rather than copies of
 *		the current process.  This can reduce memory consumption for
 *		large processes, at the expense of startup time (which
 *		shouldn't be too bad anyway, because of the resolver design).
 *		If the filename is null, a default set up at install time is
 *		used.  It's probably a good idea to leave it alone.
 */

void bres_exec(const char *file)
{
  /* Nothin' doin' */
}

/* --- @report@ --- *
 *
 * Arguments:	@bres_client *c@ = client descriptor block
 *		@adns_answer *a@ = A-record answer from resolver library
 *		@adns_rr_addr *av@ = vector of address records
 *		@int an@ = number of address records (must be positive)
 *		@char **nv@ = vector of name strings
 *		@int nn@ = number of name strings (must be positive)
 *
 * Returns:	---
 *
 * Use:		Formats the given answer into a @struct hostent@ and reports
 *		it to the waiting client application.
 */

static void report(bres_client *rc, adns_answer *a,
		   adns_rr_addr *av, int an,
		   char **nv, int nn)
{
  struct hostent h;
  char *n[16];
  char *aa[16];
  int i, j;

  j = 0;
  if (a->cname) n[j++] = a->cname;
  else { n[j++] = *nv; nv++; nn--; }
  for (i = 0; i < nn && j < N(n) - 1; i++)
    if (strcmp(n[0], nv[i]) != 0) n[j++] = nv[i];
  n[j++] = 0;
  for (i = j = 0; i < an && j < N(av) - 1; i++) {
    if (av[i].addr.sa.sa_family == AF_INET)
      aa[j++] = (char *)&av[i].addr.inet.sin_addr;
  }
  aa[j++] = 0;
  h.h_name = n[0];
  h.h_aliases = n + 1;
  h.h_addrtype = AF_INET;
  h.h_length = sizeof(struct in_addr);
  h.h_addr_list = aa;
  rc->func(&h, rc->p);  
}

/* --- @beforehook@, @afterhook@ --- *
 *
 * Arguments:	@sel_state *s@ = select state
 *		@sel_args *sa@ = argument block
 *		@void *p@ = uninteresting pointer
 *
 * Returns:	---
 *
 * Use:		Processes the selector's arguments before @select@ is
 *		called, to allow ADNS to do its thing.
 */

static void beforehook(sel_state *s, sel_args *sa, void *p)
{
  adns_beforeselect(ads, &sa->maxfd,
		    &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
		    &sa->tvp, &sa->tv, &sa->now);
}

static void afterhook(sel_state *s, sel_args *sa, void *p)
{
  void *c;
  bres_client *rc;
  adns_query q;
  adns_answer *a, *aa;
  int e;
  int i;

  adns_afterselect(ads, sa->maxfd,
		   &sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
		   &sa->now);
  while (q = 0, (e = adns_check(ads, &q, &a, &c)) == 0) {
    rc = c;
    if (a->status != 0)
      goto fail;
    else switch (rc->q) {
      case adns_r_addr:
	assert(a->type == adns_r_addr);
	xfree(rc->u.name);
	report(rc, a, a->rrs.addr, a->nrrs, &a->owner, 1);
	free(a);
	break;
      case adns_r_ptr:
	if (a->type == adns_r_ptr) {
	  rc->a = a;
	  if ((e = adns_submit(ads, a->rrs.str[0], adns_r_addr,
			       0, rc, &q)) != 0)
	    goto fail;
	  rc->aq = q;
	} else {
	  assert(a->type == adns_r_addr);
	  for (i = 0; i < a->nrrs; i++) {
	    if (a->rrs.addr[i].addr.sa.sa_family == AF_INET &&
		a->rrs.addr[i].addr.inet.sin_addr.s_addr ==
		  rc->u.addr.s_addr)
	      goto match;
	  }
	  goto fail;
	match:
	  aa = rc->a;
	  report(rc, a, &a->rrs.addr[i], 1, aa->rrs.str, aa->nrrs);
	  free(aa);
	  free(a);
	}
	break;
      default:
	abort();
    }
    continue;

  fail:
    if (rc->q == adns_r_addr) xfree(rc->u.name);
    if (rc->a) free(rc->a);
    rc->func(0, rc->p);
    free(a);
  }
}

/* --- @bres_init@ --- *
 *
 * Arguments:	@sel_state *s@ = pointer to select multiplexor
 *
 * Returns:	---
 *
 * Use:		Initializes the background resolver for use.
 */

void bres_init(sel_state *s)
{
  int e;

  if ((e = adns_init(&ads, adns_if_noautosys, 0)) != 0) {
    moan("adns_init failed: resolver won't work");
    return;
  }
  sel_addhook(s, &selhook, beforehook, afterhook, 0);
  sel = s;
}

/*----- That's all, folks -------------------------------------------------*/
Commit	Line	Data
14d7100d	1	/* --c--
14d7100d	2	*
1dc93196	3	* $Id$
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
14d7100d	42	#ifndef HAVE_ADNS
	43	# error "You need the ADNS library to compile this file."
	44	#endif
	45
	46	/----- Header files ------------------------------------------------------/
	47
	48	#include <assert.h>
	49	#include <errno.h>
	50	#include <signal.h>
	51	#include <stdio.h>
	52	#include <stdlib.h>
	53	#include <string.h>
	54
	55	#include <sys/types.h>
	56	#include <sys/time.h>
	57	#include <unistd.h>
	58	#include <sys/wait.h>
	59
	60	#include <sys/socket.h>
	61	#include <netinet/in.h>
	62	#include <arpa/inet.h>
	63	#include <netdb.h>
	64
	65	#include <adns.h>
	66
	67	#include "alloc.h"
	68	#include "bres.h"
	69	#include "macros.h"
	70	#include "report.h"
	71	#include "sel.h"
	72
	73	/----- Static variables --------------------------------------------------/
	74
	75	static adns_state ads;
	76	static sel_state *sel;
	77	static sel_hook selhook;
	78
	79	/----- Main code ---------------------------------------------------------/
	80
	81	/* --- @bres_abort@ --- *
	82	*
	83	* Arguments: @bres_client *rc@ = pointer to client block
	84	*
	85	* Returns: ---
	86	*
	87	* Use: Removes a queued job.
	88	*/
	89
	90	void bres_abort(bres_client *rc)
	91	{
	92	if (rc->q == adns_r_addr) xfree(rc->u.name);
	93	if (rc->a) free(rc->a);
	94	adns_cancel(rc->aq);
	95	}
	96
	97	/* --- @bres_byaddr@ --- *
	98	*
	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
	103	*
	104	* Returns: ---
	105	*
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
108	* it.
109	*/
110
111	void bres_byaddr(bres_client *rc, struct in_addr addr,
112	void (func)(struct hostent /h/, void /p*/),
113	void *p)
114	{
115	int e;
116	struct sockaddr_in sin;
117
118	if (!ads) goto fail;
119	sin.sin_family = AF_INET;
120	sin.sin_addr = addr;
121	sin.sin_port = 0;
122	if ((e = adns_submit_reverse(ads, (struct sockaddr *)&sin, adns_r_ptr,
123	0, rc, &rc->aq)) != 0)
124	goto fail;
125	rc->a = 0;
126	rc->q = adns_r_ptr;
127	rc->u.addr = addr;
128	rc->func = func;
129	rc->p = p;
130	return;
131
132	fail:
133	func(0, p);
134	}
135
136	/* --- @bres_byname@ --- *
137	*
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
142	*
143	* Returns: ---
144	*
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
147	* it.
148	*/
149
150	void bres_byname(bres_client rc, const char name,
151	void (func)(struct hostent /h/, void /p*/),
152	void *p)
153	{
154	int e;
155
156	if (!ads) goto fail;
157	if ((e = adns_submit(ads, name, adns_r_addr,
4f6d400b	158	adns_qf_search \| adns_qf_owner, rc, &rc->aq)) != 0)
14d7100d	159	goto fail;
	160	rc->a = 0;
	161	rc->q = adns_r_addr;
	162	rc->u.name = xstrdup(name);
	163	rc->func = func;
	164	rc->p = p;
	165	return;
	166
	167	fail:
	168	func(0, p);
	169	}
	170
	171	/* --- @bres_exec@ --- *
	172	*
	173	* Arguments: @const char *file@ = file containing server code or null
	174	*
	175	* Returns: ---
	176	*
	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.
	183	*/
	184
	185	void bres_exec(const char *file)
	186	{
	187	/* Nothin' doin' */
	188	}
	189
	190	/* --- @report@ --- *
	191	*
	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)
	198	*
	199	* Returns: ---
	200	*
	201	* Use: Formats the given answer into a @struct hostent@ and reports
	202	* it to the waiting client application.
	203	*/
	204
	205	static void report(bres_client rc, adns_answer a,
	206	adns_rr_addr *av, int an,
	207	char **nv, int nn)
	208	{
	209	struct hostent h;
	210	char *n[16];
	211	char *aa[16];
	212	int i, j;
	213
	214	j = 0;
	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];
	219	n[j++] = 0;
	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;
223	}
224	aa[j++] = 0;
225	h.h_name = n[0];
226	h.h_aliases = n + 1;
227	h.h_addrtype = AF_INET;
228	h.h_length = sizeof(struct in_addr);
229	h.h_addr_list = aa;
230	rc->func(&h, rc->p);
231	}
232
233	/* --- @beforehook@, @afterhook@ --- *
234	*
235	* Arguments: @sel_state *s@ = select state
236	* @sel_args *sa@ = argument block
237	* @void *p@ = uninteresting pointer
238	*
239	* Returns: ---
240	*
241	* Use: Processes the selector's arguments before @select@ is
242	* called, to allow ADNS to do its thing.
243	*/
244
245	static void beforehook(sel_state s, sel_args sa, void *p)
246	{
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);
250	}
251
252	static void afterhook(sel_state s, sel_args sa, void *p)
253	{
254	void *c;
255	bres_client *rc;
256	adns_query q;
24a657cc	257	adns_answer a, aa;
14d7100d	258	int e;
	259	int i;
	260
	261	adns_afterselect(ads, sa->maxfd,
	262	&sa->fd[SEL_READ], &sa->fd[SEL_WRITE], &sa->fd[SEL_EXC],
	263	&sa->now);
	264	while (q = 0, (e = adns_check(ads, &q, &a, &c)) == 0) {
	265	rc = c;
	266	if (a->status != 0)
	267	goto fail;
	268	else switch (rc->q) {
	269	case adns_r_addr:
	270	assert(a->type == adns_r_addr);
1dc93196	271	xfree(rc->u.name);
24a657cc	272	report(rc, a, a->rrs.addr, a->nrrs, &a->owner, 1);
14d7100d	273	free(a);
	274	break;
	275	case adns_r_ptr:
	276	if (a->type == adns_r_ptr) {
	277	rc->a = a;
	278	if ((e = adns_submit(ads, a->rrs.str[0], adns_r_addr,
	279	0, rc, &q)) != 0)
	280	goto fail;
	281	rc->aq = q;
	282	} else {
	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 ==
	287	rc->u.addr.s_addr)
	288	goto match;
	289	}
	290	goto fail;
	291	match:
24a657cc	292	aa = rc->a;
	293	report(rc, a, &a->rrs.addr[i], 1, aa->rrs.str, aa->nrrs);
	294	free(aa);
14d7100d	295	free(a);
	296	}
	297	break;
	298	default:
	299	abort();
	300	}
	301	continue;
	302
	303	fail:
14d7100d	304	if (rc->q == adns_r_addr) xfree(rc->u.name);
14d7100d	305	if (rc->a) free(rc->a);
24a657cc	306	rc->func(0, rc->p);
14d7100d	307	free(a);
	308	}
	309	}
	310
	311	/* --- @bres_init@ --- *
	312	*
	313	* Arguments: @sel_state *s@ = pointer to select multiplexor
	314	*
	315	* Returns: ---
	316	*
	317	* Use: Initializes the background resolver for use.
	318	*/
	319
	320	void bres_init(sel_state *s)
	321	{
	322	int e;
	323
d46d1a2f	324	if ((e = adns_init(&ads, adns_if_noautosys, 0)) != 0) {
14d7100d	325	moan("adns_init failed: resolver won't work");
	326	return;
	327	}
	328	sel_addhook(s, &selhook, beforehook, afterhook, 0);
	329	sel = s;
	330	}
	331
	332	/----- That's all, folks -------------------------------------------------/