lib/addns/dnssock.c

   1 /*
   2   Linux DNS client library implementation
   3
   4   Copyright (C) 2006 Krishna Ganugapati <krishnag@centeris.com>
   5   Copyright (C) 2006 Gerald Carter <jerry@samba.org>
   6
   7      ** NOTE! The following LGPL license applies to the libaddns
   8      ** library. This does NOT imply that all of Samba is released
   9      ** under the LGPL
  10
  11   This library is free software; you can redistribute it and/or
  12   modify it under the terms of the GNU Lesser General Public
  13   License as published by the Free Software Foundation; either
  14   version 2.1 of the License, or (at your option) any later version.
  15
  16   This library is distributed in the hope that it will be useful,
  17   but WITHOUT ANY WARRANTY; without even the implied warranty of
  18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  19   Lesser General Public License for more details.
  20
  21   You should have received a copy of the GNU Lesser General Public
  22   License along with this library; if not, see <http://www.gnu.org/licenses/>.
  23 */
  24
  25 #include "replace.h"
  26 #include "dns.h"
  27 #include <sys/time.h>
  28 #include <unistd.h>
  29 #include "system/select.h"
  30
  31 static int destroy_dns_connection(struct dns_connection *conn)
  32 {
  33         return close(conn->s);
  34 }
  35
  36 /********************************************************************
  37 ********************************************************************/
  38
  39 static DNS_ERROR dns_tcp_open( const char *nameserver,
  40                                TALLOC_CTX *mem_ctx,
  41                                struct dns_connection **result )
  42 {
  43         uint32_t ulAddress;
  44         struct hostent *pHost;
  45         struct sockaddr_in s_in;
  46         struct dns_connection *conn;
  47         int res;
  48
  49         if (!(conn = talloc(mem_ctx, struct dns_connection))) {
  50                 return ERROR_DNS_NO_MEMORY;
  51         }
  52
  53         if ( (ulAddress = inet_addr( nameserver )) == INADDR_NONE ) {
  54                 if ( (pHost = gethostbyname( nameserver )) == NULL ) {
  55                         TALLOC_FREE(conn);
  56                         return ERROR_DNS_INVALID_NAME_SERVER;
  57                 }
  58                 memcpy( &ulAddress, pHost->h_addr, pHost->h_length );
  59         }
  60
  61         conn->s = socket( PF_INET, SOCK_STREAM, 0 );
  62         if (conn->s == -1) {
  63                 TALLOC_FREE(conn);
  64                 return ERROR_DNS_CONNECTION_FAILED;
  65         }
  66
  67         talloc_set_destructor(conn, destroy_dns_connection);
  68
  69         s_in.sin_family = AF_INET;
  70         s_in.sin_addr.s_addr = ulAddress;
  71         s_in.sin_port = htons( DNS_TCP_PORT );
  72
  73         res = connect(conn->s, (struct sockaddr*)&s_in, sizeof( s_in ));
  74         if (res == -1) {
  75                 TALLOC_FREE(conn);
  76                 return ERROR_DNS_CONNECTION_FAILED;
  77         }
  78
  79         conn->hType = DNS_TCP;
  80
  81         *result = conn;
  82         return ERROR_DNS_SUCCESS;
  83 }
  84
  85 /********************************************************************
  86 ********************************************************************/
  87
  88 static DNS_ERROR dns_udp_open( const char *nameserver,
  89                                TALLOC_CTX *mem_ctx,
  90                                struct dns_connection **result )
  91 {
  92         unsigned long ulAddress;
  93         struct hostent *pHost;
  94         struct sockaddr_in RecvAddr;
  95         struct dns_connection *conn;
  96
  97         if (!(conn = talloc(NULL, struct dns_connection))) {
  98                 return ERROR_DNS_NO_MEMORY;
  99         }
 100
 101         if ( (ulAddress = inet_addr( nameserver )) == INADDR_NONE ) {
 102                 if ( (pHost = gethostbyname( nameserver )) == NULL ) {
 103                         TALLOC_FREE(conn);
 104                         return ERROR_DNS_INVALID_NAME_SERVER;
 105                 }
 106                 memcpy( &ulAddress, pHost->h_addr, pHost->h_length );
 107         }
 108
 109         /* Create a socket for sending data */
 110
 111         conn->s = socket( AF_INET, SOCK_DGRAM, IPPROTO_UDP );
 112         if (conn->s == -1) {
 113                 TALLOC_FREE(conn);
 114                 return ERROR_DNS_CONNECTION_FAILED;
 115         }
 116
 117         talloc_set_destructor(conn, destroy_dns_connection);
 118
 119         /* Set up the RecvAddr structure with the IP address of
 120            the receiver (in this example case "123.456.789.1")
 121            and the specified port number. */
 122
 123         ZERO_STRUCT(RecvAddr);
 124         RecvAddr.sin_family = AF_INET;
 125         RecvAddr.sin_port = htons( DNS_UDP_PORT );
 126         RecvAddr.sin_addr.s_addr = ulAddress;
 127
 128         conn->hType = DNS_UDP;
 129         memcpy( &conn->RecvAddr, &RecvAddr, sizeof( struct sockaddr_in ) );
 130
 131         *result = conn;
 132         return ERROR_DNS_SUCCESS;
 133 }
 134
 135 /********************************************************************
 136 ********************************************************************/
 137
 138 DNS_ERROR dns_open_connection( const char *nameserver, int32 dwType,
 139                     TALLOC_CTX *mem_ctx,
 140                     struct dns_connection **conn )
 141 {
 142         switch ( dwType ) {
 143         case DNS_TCP:
 144                 return dns_tcp_open( nameserver, mem_ctx, conn );
 145         case DNS_UDP:
 146                 return dns_udp_open( nameserver, mem_ctx, conn );
 147         }
 148
 149         return ERROR_DNS_INVALID_PARAMETER;
 150 }
 151
 152 static DNS_ERROR write_all(int fd, uint8 *data, size_t len)
 153 {
 154         size_t total = 0;
 155
 156         while (total < len) {
 157
 158                 ssize_t ret = write(fd, data + total, len - total);
 159
 160                 if (ret <= 0) {
 161                         /*
 162                          * EOF or error
 163                          */
 164                         return ERROR_DNS_SOCKET_ERROR;
 165                 }
 166
 167                 total += ret;
 168         }
 169
 170         return ERROR_DNS_SUCCESS;
 171 }
 172
 173 static DNS_ERROR dns_send_tcp(struct dns_connection *conn,
 174                               const struct dns_buffer *buf)
 175 {
 176         uint16 len = htons(buf->offset);
 177         DNS_ERROR err;
 178
 179         err = write_all(conn->s, (uint8 *)&len, sizeof(len));
 180         if (!ERR_DNS_IS_OK(err)) return err;
 181
 182         return write_all(conn->s, buf->data, buf->offset);
 183 }
 184
 185 static DNS_ERROR dns_send_udp(struct dns_connection *conn,
 186                               const struct dns_buffer *buf)
 187 {
 188         ssize_t ret;
 189
 190         ret = sendto(conn->s, buf->data, buf->offset, 0,
 191                      (struct sockaddr *)&conn->RecvAddr,
 192                      sizeof(conn->RecvAddr));
 193
 194         if (ret != buf->offset) {
 195                 return ERROR_DNS_SOCKET_ERROR;
 196         }
 197
 198         return ERROR_DNS_SUCCESS;
 199 }
 200
 201 DNS_ERROR dns_send(struct dns_connection *conn, const struct dns_buffer *buf)
 202 {
 203         if (conn->hType == DNS_TCP) {
 204                 return dns_send_tcp(conn, buf);
 205         }
 206
 207         if (conn->hType == DNS_UDP) {
 208                 return dns_send_udp(conn, buf);
 209         }
 210
 211         return ERROR_DNS_INVALID_PARAMETER;
 212 }
 213
 214 static DNS_ERROR read_all(int fd, uint8 *data, size_t len)
 215 {
 216         size_t total = 0;
 217
 218         while (total < len) {
 219                 struct pollfd pfd;
 220                 ssize_t ret;
 221                 int fd_ready;
 222
 223                 ZERO_STRUCT(pfd);
 224                 pfd.fd = fd;
 225                 pfd.events = POLLIN|POLLHUP;
 226
 227                 fd_ready = poll(&pfd, 1, 10000);
 228                 if ( fd_ready == 0 ) {
 229                         /* read timeout */
 230                         return ERROR_DNS_SOCKET_ERROR;
 231                 }
 232
 233                 ret = read(fd, data + total, len - total);
 234                 if (ret <= 0) {
 235                         /* EOF or error */
 236                         return ERROR_DNS_SOCKET_ERROR;
 237                 }
 238
 239                 total += ret;
 240         }
 241
 242         return ERROR_DNS_SUCCESS;
 243 }
 244
 245 static DNS_ERROR dns_receive_tcp(TALLOC_CTX *mem_ctx,
 246                                  struct dns_connection *conn,
 247                                  struct dns_buffer **presult)
 248 {
 249         struct dns_buffer *buf;
 250         DNS_ERROR err;
 251         uint16 len;
 252
 253         if (!(buf = talloc_zero(mem_ctx, struct dns_buffer))) {
 254                 return ERROR_DNS_NO_MEMORY;
 255         }
 256
 257         err = read_all(conn->s, (uint8 *)&len, sizeof(len));
 258         if (!ERR_DNS_IS_OK(err)) {
 259                 return err;
 260         }
 261
 262         buf->size = ntohs(len);
 263
 264         if (buf->size) {
 265                 if (!(buf->data = talloc_array(buf, uint8, buf->size))) {
 266                         TALLOC_FREE(buf);
 267                         return ERROR_DNS_NO_MEMORY;
 268                 }
 269         } else {
 270                 buf->data = NULL;
 271         }
 272
 273         err = read_all(conn->s, buf->data, buf->size);
 274         if (!ERR_DNS_IS_OK(err)) {
 275                 TALLOC_FREE(buf);
 276                 return err;
 277         }
 278
 279         *presult = buf;
 280         return ERROR_DNS_SUCCESS;
 281 }
 282
 283 static DNS_ERROR dns_receive_udp(TALLOC_CTX *mem_ctx,
 284                                  struct dns_connection *conn,
 285                                  struct dns_buffer **presult)
 286 {
 287         struct dns_buffer *buf;
 288         ssize_t received;
 289
 290         if (!(buf = talloc_zero(mem_ctx, struct dns_buffer))) {
 291                 return ERROR_DNS_NO_MEMORY;
 292         }
 293
 294         /*
 295          * UDP based DNS can only be 512 bytes
 296          */
 297
 298         if (!(buf->data = talloc_array(buf, uint8, 512))) {
 299                 TALLOC_FREE(buf);
 300                 return ERROR_DNS_NO_MEMORY;
 301         }
 302
 303         received = recv(conn->s, (void *)buf->data, 512, 0);
 304
 305         if (received == -1) {
 306                 TALLOC_FREE(buf);
 307                 return ERROR_DNS_SOCKET_ERROR;
 308         }
 309
 310         if (received > 512) {
 311                 TALLOC_FREE(buf);
 312                 return ERROR_DNS_BAD_RESPONSE;
 313         }
 314
 315         buf->size = received;
 316         buf->offset = 0;
 317
 318         *presult = buf;
 319         return ERROR_DNS_SUCCESS;
 320 }
 321
 322 DNS_ERROR dns_receive(TALLOC_CTX *mem_ctx, struct dns_connection *conn,
 323                       struct dns_buffer **presult)
 324 {
 325         if (conn->hType == DNS_TCP) {
 326                 return dns_receive_tcp(mem_ctx, conn, presult);
 327         }
 328
 329         if (conn->hType == DNS_UDP) {
 330                 return dns_receive_udp(mem_ctx, conn, presult);
 331         }
 332
 333         return ERROR_DNS_INVALID_PARAMETER;
 334 }
 335
 336 DNS_ERROR dns_transaction(TALLOC_CTX *mem_ctx, struct dns_connection *conn,
 337                           const struct dns_request *req,
 338                           struct dns_request **resp)
 339 {
 340         struct dns_buffer *buf = NULL;
 341         DNS_ERROR err;
 342
 343         err = dns_marshall_request(mem_ctx, req, &buf);
 344         if (!ERR_DNS_IS_OK(err)) goto error;
 345
 346         err = dns_send(conn, buf);
 347         if (!ERR_DNS_IS_OK(err)) goto error;
 348         TALLOC_FREE(buf);
 349
 350         err = dns_receive(mem_ctx, conn, &buf);
 351         if (!ERR_DNS_IS_OK(err)) goto error;
 352
 353         err = dns_unmarshall_request(mem_ctx, buf, resp);
 354
 355  error:
 356         TALLOC_FREE(buf);
 357         return err;
 358 }
 359
 360 DNS_ERROR dns_update_transaction(TALLOC_CTX *mem_ctx,
 361                                  struct dns_connection *conn,
 362                                  struct dns_update_request *up_req,
 363                                  struct dns_update_request **up_resp)
 364 {
 365         struct dns_request *resp;
 366         DNS_ERROR err;
 367
 368         err = dns_transaction(mem_ctx, conn, dns_update2request(up_req),
 369                               &resp);
 370
 371         if (!ERR_DNS_IS_OK(err)) return err;
 372
 373         *up_resp = dns_request2update(resp);
 374         return ERROR_DNS_SUCCESS;
 375 }