dnsinfo/dnsinfo_create.c

   1 /*
   2  * Copyright (c) 2004, 2006, 2009 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <stdlib.h>
  25 #include <strings.h>
  26 #include <mach/mach.h>
  27 #include <mach/mach_error.h>
  28
  29 #include "dnsinfo_create.h"
  30 #include "dnsinfo_private.h"
  31 #include "shared_dns_info.h"
  32
  33
  34 #define ROUNDUP(a, size) \
  35         (((a) & ((size)-1)) ? (1 + ((a) | ((size)-1))) : (a))
  36
  37
  38 /*
  39  * to avoid extra calls to realloc() we want to pre-allocate the initial
  40  * resolver and configuration buffers of a sufficient size that they would
  41  * not normally need to be expanded.
  42  */
  43 #define INITIAL_CONFIGURATION_BUF_SIZE  8192
  44 #define INITIAL_RESOLVER_BUF_SIZE       1024
  45
  46
  47 /*
  48  * DNS [configuration] buffer functions
  49  */
  50
  51
  52 dns_create_config_t
  53 _dns_configuration_create()
  54 {
  55         _dns_config_buf_t       *config;
  56
  57         config = calloc(1, INITIAL_CONFIGURATION_BUF_SIZE);
  58 //      config->n_attribute = 0;
  59 //      config->n_padding = 0;
  60         return (dns_create_config_t)config;
  61 }
  62
  63
  64 static void
  65 config_add_attribute(dns_create_config_t        *_config,
  66                      uint32_t                   attribute_type,
  67                      uint32_t                   attribute_length,
  68                      void                       *attribute,
  69                      uint32_t                   extra_padding)
  70 {
  71         _dns_config_buf_t       *config = (_dns_config_buf_t *)*_config;
  72         dns_attribute_t         *header;
  73         int                     i;
  74         uint32_t                newLen;
  75         uint32_t                newSize;
  76         uint32_t                oldLen;
  77         uint32_t                rounded_length;
  78
  79         // add space
  80
  81         oldLen         = ntohl(config->n_attribute);
  82         rounded_length = ROUNDUP(attribute_length, sizeof(uint32_t));
  83         newLen         = sizeof(dns_attribute_t) + rounded_length;
  84         newSize = sizeof(_dns_config_buf_t) + oldLen + newLen;
  85         if (newSize > INITIAL_CONFIGURATION_BUF_SIZE) {
  86                 config = realloc(config, newSize);
  87         }
  88         config->n_attribute = htonl(ntohl(config->n_attribute) + newLen);
  89
  90         // increment additional padding that will be needed (later)
  91         config->n_padding = htonl(ntohl(config->n_padding) + extra_padding);
  92
  93         // add attribute [header]
  94
  95         header = (dns_attribute_t *)&config->attribute[oldLen];
  96         header->type   = htonl(attribute_type);
  97         header->length = htonl(newLen);
  98
  99         // add attribute [data]
 100
 101         bcopy(attribute, &header->attribute[0], attribute_length);
 102         for (i = attribute_length; i < rounded_length; i++) {
 103                 header->attribute[i] = 0;
 104         }
 105
 106         *_config = (dns_create_config_t)config;
 107         return;
 108 }
 109
 110
 111 void
 112 _dns_configuration_add_resolver(dns_create_config_t     *_config,
 113                                 dns_create_resolver_t   _resolver)
 114 {
 115         _dns_config_buf_t       *config         = (_dns_config_buf_t *)*_config;
 116         uint32_t                padding         = 0;
 117         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)_resolver;
 118
 119         /*
 120          * compute the amount of space that will be needed for
 121          * pointers to the resolver, the nameservers, the search
 122          * list, and the sortaddr list.
 123          */
 124         padding += sizeof(DNS_PTR(dns_resolver_t *, x));
 125         if (resolver->resolver.n_nameserver != 0) {
 126                 padding += ntohl(resolver->resolver.n_nameserver) * sizeof(DNS_PTR(struct sockaddr *, x));
 127         }
 128         if (resolver->resolver.n_search != 0) {
 129                 padding += ntohl(resolver->resolver.n_search) * sizeof(DNS_PTR(char *, x));
 130         }
 131         if (resolver->resolver.n_sortaddr != 0) {
 132                 padding += ntohl(resolver->resolver.n_sortaddr) * sizeof(DNS_PTR(dns_sortaddr_t *, x));
 133         }
 134
 135         config->config.n_resolver = htonl(ntohl(config->config.n_resolver) + 1);
 136
 137         config_add_attribute(_config,
 138                              CONFIG_ATTRIBUTE_RESOLVER,
 139                              sizeof(_dns_resolver_buf_t) + ntohl(resolver->n_attribute),
 140                              (void *)resolver,
 141                              padding);
 142
 143         return;
 144 }
 145
 146
 147 _Bool
 148 _dns_configuration_store(dns_create_config_t *_config)
 149 {
 150         dnsDataOut_t            dataRef = NULL;
 151         mach_msg_type_number_t  dataLen = 0;
 152         mach_port_t             server;
 153         kern_return_t           status;
 154
 155         server = _dns_configuration_server_port();
 156         if (server == MACH_PORT_NULL) {
 157                 return FALSE;
 158         }
 159
 160         if (_config != NULL) {
 161                 _dns_config_buf_t       *config = (_dns_config_buf_t *)*_config;
 162
 163                 if (config != NULL) {
 164                         dataRef = (dnsDataOut_t)config;
 165                         dataLen = sizeof(_dns_config_buf_t) + ntohl(config->n_attribute);
 166                 }
 167         }
 168
 169         status = shared_dns_infoSet(server, dataRef, dataLen);
 170         (void) mach_port_deallocate(mach_task_self(), server);
 171         if (status != KERN_SUCCESS) {
 172                 mach_error("shared_dns_infoSet():", status);
 173                 return FALSE;
 174         }
 175
 176         return TRUE;
 177 }
 178
 179
 180 void
 181 _dns_configuration_free(dns_create_config_t *_config)
 182 {
 183         _dns_config_buf_t       *config = (_dns_config_buf_t *)*_config;
 184
 185         free(config);
 186         *_config = NULL;
 187         return;
 188 }
 189
 190
 191 /*
 192  * DNS resolver configuration functions
 193  */
 194
 195 dns_create_resolver_t
 196 _dns_resolver_create()
 197 {
 198         _dns_resolver_buf_t     *buf;
 199
 200         buf = calloc(1, INITIAL_RESOLVER_BUF_SIZE);
 201 //      buf->n_attribute = 0;
 202         return (dns_create_resolver_t)buf;
 203 }
 204
 205
 206 static void
 207 _dns_resolver_add_attribute(dns_create_resolver_t       *_resolver,
 208                             uint32_t                    attribute_type,
 209                             uint32_t                    attribute_length,
 210                             void                        *attribute)
 211 {
 212         dns_attribute_t         *header;
 213         int                     i;
 214         uint32_t                newLen;
 215         uint32_t                newSize;
 216         uint32_t                oldLen;
 217         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 218         uint32_t                rounded_length;
 219
 220         // add space
 221
 222         oldLen         = ntohl(resolver->n_attribute);
 223         rounded_length = ROUNDUP(attribute_length, sizeof(uint32_t));
 224         newLen         = sizeof(dns_attribute_t) + rounded_length;
 225         newSize = sizeof(_dns_resolver_buf_t) + oldLen + newLen;
 226         if (newSize > INITIAL_RESOLVER_BUF_SIZE) {
 227                 resolver = realloc(resolver, newSize);
 228         }
 229         resolver->n_attribute = htonl(ntohl(resolver->n_attribute) + newLen);
 230
 231         // add attribute [header]
 232
 233         header = (dns_attribute_t *)&resolver->attribute[oldLen];
 234         header->type   = htonl(attribute_type);
 235         header->length = htonl(newLen);
 236
 237         // add attribute [data]
 238
 239         bcopy(attribute, &header->attribute[0], attribute_length);
 240         for (i = attribute_length; i < rounded_length; i++) {
 241                 header->attribute[i] = 0;
 242         }
 243
 244         *_resolver = (dns_create_resolver_t)resolver;
 245         return;
 246 }
 247
 248
 249 void
 250 _dns_resolver_set_domain(dns_create_resolver_t *_resolver, const char *domain)
 251 {
 252         _dns_resolver_add_attribute(_resolver, RESOLVER_ATTRIBUTE_DOMAIN, strlen(domain) + 1, (void *)domain);
 253         return;
 254 }
 255
 256
 257 void
 258 _dns_resolver_add_nameserver(dns_create_resolver_t *_resolver, struct sockaddr *nameserver)
 259 {
 260         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 261
 262         resolver->resolver.n_nameserver = htonl(ntohl(resolver->resolver.n_nameserver) + 1);
 263         _dns_resolver_add_attribute(_resolver, RESOLVER_ATTRIBUTE_ADDRESS, nameserver->sa_len, (void *)nameserver);
 264         return;
 265 }
 266
 267
 268 void
 269 _dns_resolver_set_port(dns_create_resolver_t *_resolver, uint16_t port)
 270 {
 271         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 272
 273         resolver->resolver.port = htons(port);
 274         return;
 275 }
 276
 277
 278 void
 279 _dns_resolver_add_search(dns_create_resolver_t *_resolver, const char *search)
 280 {
 281         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 282
 283         resolver->resolver.n_search = htonl(ntohl(resolver->resolver.n_search) + 1);
 284         _dns_resolver_add_attribute(_resolver, RESOLVER_ATTRIBUTE_SEARCH, strlen(search) + 1, (void *)search);
 285         return;
 286 }
 287
 288
 289 void
 290 _dns_resolver_add_sortaddr(dns_create_resolver_t *_resolver, dns_sortaddr_t *sortaddr)
 291 {
 292         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 293
 294         resolver->resolver.n_sortaddr = htonl(ntohl(resolver->resolver.n_sortaddr) + 1);
 295         _dns_resolver_add_attribute(_resolver, RESOLVER_ATTRIBUTE_SORTADDR, sizeof(dns_sortaddr_t), (void *)sortaddr);
 296         return;
 297 }
 298
 299
 300 void
 301 _dns_resolver_set_options(dns_create_resolver_t *_resolver, const char *options)
 302 {
 303         _dns_resolver_add_attribute(_resolver, RESOLVER_ATTRIBUTE_OPTIONS, strlen(options) + 1, (void *)options);
 304         return;
 305 }
 306
 307
 308 void
 309 _dns_resolver_set_timeout(dns_create_resolver_t *_resolver, uint32_t timeout)
 310 {
 311         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 312
 313         resolver->resolver.timeout = htonl(timeout);
 314         return;
 315 }
 316
 317
 318 void
 319 _dns_resolver_set_order(dns_create_resolver_t *_resolver, uint32_t order)
 320 {
 321         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 322
 323         resolver->resolver.search_order = htonl(order);
 324         return;
 325 }
 326
 327
 328 void
 329 _dns_resolver_free(dns_create_resolver_t *_resolver)
 330 {
 331         _dns_resolver_buf_t     *resolver       = (_dns_resolver_buf_t *)*_resolver;
 332
 333         free(resolver);
 334         *_resolver = NULL;
 335         return;
 336 }