Usermode/Libraries/libnet.so_src/dns.c

   1 /*
   2  * Acess2 Networking Toolkit
   3  * By John Hodge (thePowersGang)
   4  *
   5  * dns.c
   6  * - Hostname<->Address resolution
   7  */
   8 #include <stddef.h>     // size_t / NULL
   9 #include <stdint.h>     // uint*_t
  10 #include <string.h>     // memcpy, strchr
  11 #include <assert.h>
  12 #include <acess/sys.h>  // for _SysSelect
  13 #include <acess/fd_set.h>       // FD_SET
  14 #include <net.h>
  15 #include "include/dns.h"
  16 #include "include/dns_int.h"
  17
  18 // === PROTOTYPES ===
  19 //int DNS_Query(int ServerAType, const void *ServerAddr, const char *name, enum eTypes type, enum eClass class, handle_record_t* handle_record, void *info);
  20
  21 // === CODE ===
  22 int DNS_Query(int ServerAType, const void *ServerAddr, const char *name, enum eTypes type, enum eClass class, handle_record_t* handle_record, void *info)
  23 {
  24         char    packet[512];
  25         size_t packlen = DNS_int_EncodeQuery(packet, sizeof(packet), name, type, class);
  26         if( packlen == 0 ) {
  27                 _SysDebug("DNS_Query - Serialising packet failed");
  28                 return 2;
  29         }
  30
  31         // Send and wait for reply
  32         // - Lock
  33         //  > TODO: Lock DNS queries
  34         // - Send
  35         int sock = Net_OpenSocket_UDP(ServerAType, ServerAddr, 53, 0);
  36         if( sock < 0 ) {
  37                 // Connection failed
  38                 _SysDebug("DNS_Query - UDP open failed");
  39                 // TODO: Correctly report this failure with a useful error code
  40                 return 1;
  41         }
  42         int rv = Net_UDP_SendTo(sock, 53, ServerAType, ServerAddr, packlen, packet);
  43         if( rv != packlen ) {
  44                 _SysDebug("DNS_Query - Write failed");
  45                 // TODO: Error reporting
  46                 _SysClose(sock);
  47                 return 1;
  48         }
  49         // - Wait
  50         {
  51                  int    nfd = sock + 1;
  52                 fd_set  fds;
  53                 FD_ZERO(&fds);
  54                 FD_SET(sock, &fds);
  55                 int64_t timeout = 2000; // Give it two seconds, should be long enough
  56                 rv = _SysSelect(nfd, &fds, NULL, NULL, &timeout, 0);
  57                 if( rv == 0 ) {
  58                         // Timeout with no reply, give up
  59                         _SysDebug("DNS_Query - Timeout");
  60                         _SysClose(sock);
  61                         return 1;
  62                 }
  63                 if( rv < 0 ) {
  64                         // Oops, select failed
  65                         _SysDebug("DNS_Query - Select failure");
  66                         _SysClose(sock);
  67                         return 1;
  68                 }
  69         }
  70         int return_len = Net_UDP_RecvFrom(sock, NULL, NULL, NULL, sizeof(packet), packet);
  71         if( return_len <= 0 ) {
  72                 // TODO: Error reporting
  73                 _SysDebug("DNS_Query - Read failure");
  74                 _SysClose(sock);
  75                 return 1;
  76         }
  77         _SysClose(sock);
  78         // - Release
  79         //  > TODO: Lock DNS queries
  80
  81         // For each response in the answer (and additional) sections, call the passed callback
  82         return DNS_int_ParseResponse(packet, return_len, info, handle_record);
  83 }
  84