Usermode/Libraries/libnet.so_src/hostnames.c

   1 /*
   2  * Acess2 Networking Toolkit
   3  * By John Hodge (thePowersGang)
   4  *
   5  * dns.c
   6  * - Hostname<->Address resolution
   7  */
   8 #include <net.h>
   9 #include "include/dns.h"
  10 #include <string.h>
  11 #include <stdbool.h>
  12
  13 // === TYPES ===
  14 struct sDNSServer
  15 {
  16          int    AddrType;
  17         char    AddrData[16];
  18 };
  19
  20 struct sHostEntry
  21 {
  22          int    AddrType;
  23         char    AddrData[16];
  24         char    *Names[];
  25 };
  26
  27 struct sDNSCallbackInfo
  28 {
  29          int    expected_size;
  30         void    *dest_ptr;
  31         enum eTypes     desired_type;
  32         enum eClass     desired_class;
  33         bool    have_result;
  34 };
  35
  36 // === PROTOTYPES ===
  37 void    int_DNS_callback(void *info, const char *name, enum eTypes type, enum eClass class, unsigned int ttl, size_t rdlength, const void *rdata);
  38
  39 // === GLOBALS ===
  40  int    giNumDNSServers;
  41 struct sDNSServer       *gaDNSServers;
  42  int    giNumHostEntries;
  43 struct sHostEntry       *gaHostEntries;
  44
  45 // === CODE ===
  46 int Net_Lookup_AnyAddr(const char *Name, int AddrType, void *Addr)
  47 {
  48         // 1. Load (if not loaded) the DNS config from "/Acess/Conf/dns"
  49         // - "* <ip> <ip>" for DNS server(s)
  50         // - "127.0.0.1 localhost localhost.localdomain"
  51
  52         // 2. Check the hosts list
  53         for( int i = 0; i < giNumHostEntries; i ++ )
  54         {
  55                 const struct sHostEntry* he = &gaHostEntries[i];
  56                 if( he->AddrType == AddrType )
  57                 {
  58                         for( const char * const *namep = (const char**)he->Names; *namep; namep ++ )
  59                         {
  60                                 if( strcasecmp(Name, *namep) == 0 )
  61                                 {
  62                                         memcpy(Addr, he->AddrData, Net_GetAddressSize(AddrType));
  63                                         return 0;
  64                                 }
  65                         }
  66                 }
  67         }
  68         // 3. Contact DNS server specified in config
  69         for( int i = 0; i < giNumDNSServers; i ++ )
  70         {
  71                 // TODO
  72                 const struct sDNSServer *s = &gaDNSServers[i];
  73                 struct sDNSCallbackInfo info = {
  74                         .expected_size = Net_GetAddressSize(AddrType),
  75                         .dest_ptr = Addr,
  76                         .desired_type = TYPE_A,
  77                         .desired_class = CLASS_IN,
  78                         .have_result = false
  79                         };
  80                 if( ! DNS_Query(s->AddrType, s->AddrData, Name, info.desired_type, info.desired_class, int_DNS_callback, &info) )
  81                 {
  82                         if( info.have_result )
  83                         {
  84                                 return 0;
  85                         }
  86                         else
  87                         {
  88                                 // NXDomain, I guess
  89                                 return 1;
  90                         }
  91                 }
  92         }
  93         return 1;
  94 }
  95
  96 void int_DNS_callback(void *info_v, const char *name, enum eTypes type, enum eClass class, unsigned int ttl, size_t rdlength, const void *rdata)
  97 {
  98         struct sDNSCallbackInfo *info = info_v;
  99         if( type == info->desired_type && class == info->desired_class && info->have_result == false )
 100         {
 101                 // We're just working with A and AAAA, so copying from rdata is safe
 102                 if( rdlength != info->expected_size ) {
 103                         // ... oh, that's not good
 104                         return ;
 105                 }
 106
 107                 memcpy(info->dest_ptr, rdata, rdlength);
 108
 109                 info->have_result = true;
 110         }
 111 }
 112
 113 int Net_Lookup_Name(int AddrType, const void *Addr, char *Dest[256])
 114 {
 115         return 1;
 116 }
 117