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
  27         // Send and wait for reply
  28         // - Lock
  29         //  > TODO: Lock DNS queries
  30         // - Send
  31         int sock = Net_OpenSocket_UDP(ServerAType, ServerAddr, 53, 0);
  32         if( sock < 0 ) {
  33                 // Connection failed
  34                 _SysDebug("DNS_Query - UDP open failed");
  35                 // TODO: Correctly report this failure with a useful error code
  36                 return 1;
  37         }
  38         int rv = Net_UDP_SendTo(sock, 53, ServerAType, ServerAddr, pos, packet);
  39         if( rv != pos ) {
  40                 _SysDebug("DNS_Query - Write failed");
  41                 // TODO: Error reporting
  42                 _SysClose(sock);
  43                 return 1;
  44         }
  45         // - Wait
  46         {
  47                  int    nfd = sock + 1;
  48                 fd_set  fds;
  49                 FD_ZERO(&fds);
  50                 FD_SET(sock, &fds);
  51                 int64_t timeout = 2000; // Give it two seconds, should be long enough
  52                 rv = _SysSelect(nfd, &fds, NULL, NULL, &timeout, 0);
  53                 if( rv == 0 ) {
  54                         // Timeout with no reply, give up
  55                         _SysDebug("DNS_Query - Timeout");
  56                         _SysClose(sock);
  57                         return 1;
  58                 }
  59                 if( rv < 0 ) {
  60                         // Oops, select failed
  61                         _SysDebug("DNS_Query - Select failure");
  62                         _SysClose(sock);
  63                         return 1;
  64                 }
  65         }
  66         int return_len = Net_UDP_RecvFrom(sock, NULL, NULL, NULL, sizeof(packet), packet);
  67         if( return_len <= 0 ) {
  68                 // TODO: Error reporting
  69                 _SysDebug("DNS_Query - Read failure");
  70                 _SysClose(sock);
  71                 return 1;
  72         }
  73         _SysClose(sock);
  74         // - Release
  75         //  > TODO: Lock DNS queries
  76
  77         // For each response in the answer (and additional) sections, call the passed callback
  78         return DNS_int_ParseResponse(packet, return_len, info, handle_record);
  79 }
  80