contrib/bind-9.5.2/lib/bind/irs/gen_ho.c

   1 /*
   2  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (c) 1996,1999 by Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  15  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #if defined(LIBC_SCCS) && !defined(lint)
  19 static const char rcsid[] = "$Id: gen_ho.c,v 1.5 2006/03/09 23:57:56 marka Exp $";
  20 #endif /* LIBC_SCCS and not lint */
  21
  22 /* Imports */
  23
  24 #include "port_before.h"
  25
  26 #include <sys/types.h>
  27
  28 #include <netinet/in.h>
  29 #include <arpa/nameser.h>
  30
  31 #include <errno.h>
  32 #include <stdlib.h>
  33 #include <netdb.h>
  34 #include <resolv.h>
  35 #include <stdio.h>
  36 #include <string.h>
  37
  38 #include <isc/memcluster.h>
  39 #include <irs.h>
  40
  41 #include "port_after.h"
  42
  43 #include "irs_p.h"
  44 #include "gen_p.h"
  45
  46 /* Definitions */
  47
  48 struct pvt {
  49         struct irs_rule *       rules;
  50         struct irs_rule *       rule;
  51         struct irs_ho *         ho;
  52         struct __res_state *    res;
  53         void                    (*free_res)(void *);
  54 };
  55
  56 /* Forwards */
  57
  58 static void             ho_close(struct irs_ho *this);
  59 static struct hostent * ho_byname(struct irs_ho *this, const char *name);
  60 static struct hostent * ho_byname2(struct irs_ho *this, const char *name,
  61                                    int af);
  62 static struct hostent * ho_byaddr(struct irs_ho *this, const void *addr,
  63                                   int len, int af);
  64 static struct hostent * ho_next(struct irs_ho *this);
  65 static void             ho_rewind(struct irs_ho *this);
  66 static void             ho_minimize(struct irs_ho *this);
  67 static struct __res_state * ho_res_get(struct irs_ho *this);
  68 static void             ho_res_set(struct irs_ho *this,
  69                                    struct __res_state *res,
  70                                    void (*free_res)(void *));
  71 static struct addrinfo * ho_addrinfo(struct irs_ho *this, const char *name,
  72                                      const struct addrinfo *pai);
  73
  74 static int              init(struct irs_ho *this);
  75
  76 /* Exports */
  77
  78 struct irs_ho *
  79 irs_gen_ho(struct irs_acc *this) {
  80         struct gen_p *accpvt = (struct gen_p *)this->private;
  81         struct irs_ho *ho;
  82         struct pvt *pvt;
  83
  84         if (!(pvt = memget(sizeof *pvt))) {
  85                 errno = ENOMEM;
  86                 return (NULL);
  87         }
  88         memset(pvt, 0, sizeof *pvt);
  89         if (!(ho = memget(sizeof *ho))) {
  90                 memput(pvt, sizeof *pvt);
  91                 errno = ENOMEM;
  92                 return (NULL);
  93         }
  94         memset(ho, 0x5e, sizeof *ho);
  95         pvt->rules = accpvt->map_rules[irs_ho];
  96         pvt->rule = pvt->rules;
  97         ho->private = pvt;
  98         ho->close = ho_close;
  99         ho->byname = ho_byname;
 100         ho->byname2 = ho_byname2;
 101         ho->byaddr = ho_byaddr;
 102         ho->next = ho_next;
 103         ho->rewind = ho_rewind;
 104         ho->minimize = ho_minimize;
 105         ho->res_get = ho_res_get;
 106         ho->res_set = ho_res_set;
 107         ho->addrinfo = ho_addrinfo;
 108         return (ho);
 109 }
 110
 111 /* Methods. */
 112
 113 static void
 114 ho_close(struct irs_ho *this) {
 115         struct pvt *pvt = (struct pvt *)this->private;
 116
 117         ho_minimize(this);
 118         if (pvt->res && pvt->free_res)
 119                 (*pvt->free_res)(pvt->res);
 120         memput(pvt, sizeof *pvt);
 121         memput(this, sizeof *this);
 122 }
 123
 124 static struct hostent *
 125 ho_byname(struct irs_ho *this, const char *name) {
 126         struct pvt *pvt = (struct pvt *)this->private;
 127         struct irs_rule *rule;
 128         struct hostent *rval;
 129         struct irs_ho *ho;
 130         int therrno = NETDB_INTERNAL;
 131         int softerror = 0;
 132
 133         if (init(this) == -1)
 134                 return (NULL);
 135
 136         for (rule = pvt->rules; rule; rule = rule->next) {
 137                 ho = rule->inst->ho;
 138                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 139                 errno = 0;
 140                 rval = (*ho->byname)(ho, name);
 141                 if (rval != NULL)
 142                         return (rval);
 143                 if (softerror == 0 &&
 144                     pvt->res->res_h_errno != HOST_NOT_FOUND &&
 145                     pvt->res->res_h_errno != NETDB_INTERNAL) {
 146                         softerror = 1;
 147                         therrno = pvt->res->res_h_errno;
 148                 }
 149                 if (rule->flags & IRS_CONTINUE)
 150                         continue;
 151                 /*
 152                  * The value TRY_AGAIN can mean that the service
 153                  * is not available, or just that this particular name
 154                  * cannot be resolved now.  We use the errno ECONNREFUSED
 155                  * to distinguish.  If a lookup sets that errno when
 156                  * H_ERRNO is TRY_AGAIN, we continue to try other lookup
 157                  * functions, otherwise we return the TRY_AGAIN error.
 158                  */
 159                 if (pvt->res->res_h_errno != TRY_AGAIN || errno != ECONNREFUSED)
 160                         break;
 161         }
 162         if (softerror != 0 && pvt->res->res_h_errno == HOST_NOT_FOUND)
 163                 RES_SET_H_ERRNO(pvt->res, therrno);
 164         return (NULL);
 165 }
 166
 167 static struct hostent *
 168 ho_byname2(struct irs_ho *this, const char *name, int af) {
 169         struct pvt *pvt = (struct pvt *)this->private;
 170         struct irs_rule *rule;
 171         struct hostent *rval;
 172         struct irs_ho *ho;
 173         int therrno = NETDB_INTERNAL;
 174         int softerror = 0;
 175
 176         if (init(this) == -1)
 177                 return (NULL);
 178
 179         for (rule = pvt->rules; rule; rule = rule->next) {
 180                 ho = rule->inst->ho;
 181                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 182                 errno = 0;
 183                 rval = (*ho->byname2)(ho, name, af);
 184                 if (rval != NULL)
 185                         return (rval);
 186                 if (softerror == 0 &&
 187                     pvt->res->res_h_errno != HOST_NOT_FOUND &&
 188                     pvt->res->res_h_errno != NETDB_INTERNAL) {
 189                         softerror = 1;
 190                         therrno = pvt->res->res_h_errno;
 191                 }
 192                 if (rule->flags & IRS_CONTINUE)
 193                         continue;
 194                 /*
 195                  * See the comments in ho_byname() explaining
 196                  * the interpretation of TRY_AGAIN and ECONNREFUSED.
 197                  */
 198                 if (pvt->res->res_h_errno != TRY_AGAIN || errno != ECONNREFUSED)
 199                         break;
 200         }
 201         if (softerror != 0 && pvt->res->res_h_errno == HOST_NOT_FOUND)
 202                 RES_SET_H_ERRNO(pvt->res, therrno);
 203         return (NULL);
 204 }
 205
 206 static struct hostent *
 207 ho_byaddr(struct irs_ho *this, const void *addr, int len, int af) {
 208         struct pvt *pvt = (struct pvt *)this->private;
 209         struct irs_rule *rule;
 210         struct hostent *rval;
 211         struct irs_ho *ho;
 212         int therrno = NETDB_INTERNAL;
 213         int softerror = 0;
 214
 215
 216         if (init(this) == -1)
 217                 return (NULL);
 218
 219         for (rule = pvt->rules; rule; rule = rule->next) {
 220                 ho = rule->inst->ho;
 221                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 222                 errno = 0;
 223                 rval = (*ho->byaddr)(ho, addr, len, af);
 224                 if (rval != NULL)
 225                         return (rval);
 226                 if (softerror == 0 &&
 227                     pvt->res->res_h_errno != HOST_NOT_FOUND &&
 228                     pvt->res->res_h_errno != NETDB_INTERNAL) {
 229                         softerror = 1;
 230                         therrno = pvt->res->res_h_errno;
 231                 }
 232
 233                 if (rule->flags & IRS_CONTINUE)
 234                         continue;
 235                 /*
 236                  * See the comments in ho_byname() explaining
 237                  * the interpretation of TRY_AGAIN and ECONNREFUSED.
 238                  */
 239                 if (pvt->res->res_h_errno != TRY_AGAIN || errno != ECONNREFUSED)
 240                         break;
 241         }
 242         if (softerror != 0 && pvt->res->res_h_errno == HOST_NOT_FOUND)
 243                 RES_SET_H_ERRNO(pvt->res, therrno);
 244         return (NULL);
 245 }
 246
 247 static struct hostent *
 248 ho_next(struct irs_ho *this) {
 249         struct pvt *pvt = (struct pvt *)this->private;
 250         struct hostent *rval;
 251         struct irs_ho *ho;
 252
 253         while (pvt->rule) {
 254                 ho = pvt->rule->inst->ho;
 255                 rval = (*ho->next)(ho);
 256                 if (rval)
 257                         return (rval);
 258                 if (!(pvt->rule->flags & IRS_CONTINUE))
 259                         break;
 260                 pvt->rule = pvt->rule->next;
 261                 if (pvt->rule) {
 262                         ho = pvt->rule->inst->ho;
 263                         (*ho->rewind)(ho);
 264                 }
 265         }
 266         return (NULL);
 267 }
 268
 269 static void
 270 ho_rewind(struct irs_ho *this) {
 271         struct pvt *pvt = (struct pvt *)this->private;
 272         struct irs_ho *ho;
 273
 274         pvt->rule = pvt->rules;
 275         if (pvt->rule) {
 276                 ho = pvt->rule->inst->ho;
 277                 (*ho->rewind)(ho);
 278         }
 279 }
 280
 281 static void
 282 ho_minimize(struct irs_ho *this) {
 283         struct pvt *pvt = (struct pvt *)this->private;
 284         struct irs_rule *rule;
 285
 286         if (pvt->res)
 287                 res_nclose(pvt->res);
 288         for (rule = pvt->rules; rule != NULL; rule = rule->next) {
 289                 struct irs_ho *ho = rule->inst->ho;
 290
 291                 (*ho->minimize)(ho);
 292         }
 293 }
 294
 295 static struct __res_state *
 296 ho_res_get(struct irs_ho *this) {
 297         struct pvt *pvt = (struct pvt *)this->private;
 298
 299         if (!pvt->res) {
 300                 struct __res_state *res;
 301                 res = (struct __res_state *)malloc(sizeof *res);
 302                 if (!res) {
 303                         errno = ENOMEM;
 304                         return (NULL);
 305                 }
 306                 memset(res, 0, sizeof *res);
 307                 ho_res_set(this, res, free);
 308         }
 309
 310         return (pvt->res);
 311 }
 312
 313 static void
 314 ho_res_set(struct irs_ho *this, struct __res_state *res,
 315                 void (*free_res)(void *)) {
 316         struct pvt *pvt = (struct pvt *)this->private;
 317         struct irs_rule *rule;
 318
 319         if (pvt->res && pvt->free_res) {
 320                 res_nclose(pvt->res);
 321                 (*pvt->free_res)(pvt->res);
 322         }
 323
 324         pvt->res = res;
 325         pvt->free_res = free_res;
 326
 327         for (rule = pvt->rules; rule != NULL; rule = rule->next) {
 328                 struct irs_ho *ho = rule->inst->ho;
 329
 330                 (*ho->res_set)(ho, pvt->res, NULL);
 331         }
 332 }
 333
 334 static struct addrinfo *
 335 ho_addrinfo(struct irs_ho *this, const char *name, const struct addrinfo *pai)
 336 {
 337         struct pvt *pvt = (struct pvt *)this->private;
 338         struct irs_rule *rule;
 339         struct addrinfo *rval = NULL;
 340         struct irs_ho *ho;
 341         int therrno = NETDB_INTERNAL;
 342         int softerror = 0;
 343
 344         if (init(this) == -1)
 345                 return (NULL);
 346
 347         for (rule = pvt->rules; rule; rule = rule->next) {
 348                 ho = rule->inst->ho;
 349                 RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
 350                 errno = 0;
 351                 if (ho->addrinfo == NULL) /*%< for safety */
 352                         continue;
 353                 rval = (*ho->addrinfo)(ho, name, pai);
 354                 if (rval != NULL)
 355                         return (rval);
 356                 if (softerror == 0 &&
 357                     pvt->res->res_h_errno != HOST_NOT_FOUND &&
 358                     pvt->res->res_h_errno != NETDB_INTERNAL) {
 359                         softerror = 1;
 360                         therrno = pvt->res->res_h_errno;
 361                 }
 362                 if (rule->flags & IRS_CONTINUE)
 363                         continue;
 364                 /*
 365                  * See the comments in ho_byname() explaining
 366                  * the interpretation of TRY_AGAIN and ECONNREFUSED.
 367                  */
 368                 if (pvt->res->res_h_errno != TRY_AGAIN ||
 369                     errno != ECONNREFUSED)
 370                         break;
 371         }
 372         if (softerror != 0 && pvt->res->res_h_errno == HOST_NOT_FOUND)
 373                 RES_SET_H_ERRNO(pvt->res, therrno);
 374         return (NULL);
 375 }
 376
 377 static int
 378 init(struct irs_ho *this) {
 379         struct pvt *pvt = (struct pvt *)this->private;
 380
 381         if (!pvt->res && !ho_res_get(this))
 382                 return (-1);
 383
 384         if (((pvt->res->options & RES_INIT) == 0U) &&
 385             (res_ninit(pvt->res) == -1))
 386                 return (-1);
 387
 388         return (0);
 389 }
 390
 391 /*! \file */