sdk/lib/dnslib/hostent.c

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS DNS Shared Library
   4  * FILE:        lib/dnslib/hostent.c
   5  * PURPOSE:     Functions for dealing with Host Entry structures
   6  */
   7
   8 /* INCLUDES ******************************************************************/
   9 #include "precomp.h"
  10
  11 /* DATA **********************************************************************/
  12
  13 /* FUNCTIONS *****************************************************************/
  14
  15 PHOSTENT
  16 WINAPI
  17 Hostent_Init(IN PVOID *Buffer,
  18              IN WORD AddressFamily,
  19              IN ULONG AddressSize,
  20              IN ULONG AddressCount,
  21              IN ULONG AliasCount)
  22 {
  23     PHOSTENT Hostent;
  24     ULONG_PTR BufferPosition = (ULONG_PTR)*Buffer;
  25
  26     /* Align the hostent on the buffer's 4 byte boundary */
  27     BufferPosition += 3 & ~3;
  28
  29     /* Set up the basic data */
  30     Hostent = (PHOSTENT)BufferPosition;
  31     Hostent->h_length = (WORD)AddressSize;
  32     Hostent->h_addrtype = AddressFamily;
  33
  34     /* Put aliases after Hostent */
  35     Hostent->h_aliases = (PCHAR*)((ULONG_PTR)(Hostent + 1) & ~3);
  36
  37     /* Zero it out */
  38     RtlZeroMemory(Hostent->h_aliases, AliasCount * sizeof(PCHAR));
  39
  40     /* Put addresses after aliases */
  41     Hostent->h_addr_list = (PCHAR*)
  42                            ((ULONG_PTR)Hostent->h_aliases +
  43                             (AliasCount * sizeof(PCHAR)) + sizeof(PCHAR));
  44
  45     /* Update the location */
  46     BufferPosition = (ULONG_PTR)Hostent->h_addr_list +
  47                      ((AddressCount * sizeof(PCHAR)) + sizeof(PCHAR));
  48
  49     /* Send it back */
  50     *Buffer = (PVOID)BufferPosition;
  51
  52     /* Return the hostent */
  53     return Hostent;
  54 }
  55
  56 VOID
  57 WINAPI
  58 Dns_PtrArrayToOffsetArray(PCHAR *List,
  59                           ULONG_PTR Base)
  60 {
  61     /* Loop every pointer in the list */
  62     do
  63     {
  64         /* Update the pointer */
  65         *List = (PCHAR)((ULONG_PTR)*List - Base);
  66     } while(*List++);
  67 }
  68
  69 VOID
  70 WINAPI
  71 Hostent_ConvertToOffsets(IN PHOSTENT Hostent)
  72 {
  73     /* Do we have a name? */
  74     if (Hostent->h_name)
  75     {
  76         /* Update it */
  77         Hostent->h_name -= (ULONG_PTR)Hostent;
  78     }
  79
  80     /* Do we have aliases? */
  81     if (Hostent->h_aliases)
  82     {
  83         /* Update the pointer */
  84         Hostent->h_aliases -= (ULONG_PTR)Hostent;
  85
  86         /* Fix them up */
  87         Dns_PtrArrayToOffsetArray(Hostent->h_aliases, (ULONG_PTR)Hostent);
  88     }
  89
  90     /* Do we have addresses? */
  91     if (Hostent->h_addr_list)
  92     {
  93         /* Fix them up */
  94         Dns_PtrArrayToOffsetArray(Hostent->h_addr_list, (ULONG_PTR)Hostent);
  95     }
  96 }
  97