reactos/base/services/dnsrslvr/hostsfile.c

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/*
* COPYRIGHT: See COPYING in the top level directory
* PROJECT: ReactOS system libraries
* FILE: base/services/dnsrslvr/hostsfile.c
* PURPOSE: HOSTS file routines
* PROGRAMERS: Art Yerkes
* Eric Kohl
*/
#include "precomp.h"
#include <inaddr.h>
#include <in6addr.h>
#define NDEBUG
#include <debug.h>
static WCHAR szHexChar[] = L"0123456789abcdef";
static
PWSTR
AnsiToUnicode(
PSTR NarrowString)
{
PWSTR WideString;
int WideLen;
WideLen = MultiByteToWideChar(CP_ACP,
0,
NarrowString,
-1,
NULL,
0);
if (WideLen == 0)
return NULL;
WideString = HeapAlloc(GetProcessHeap(),
0,
WideLen * sizeof(WCHAR));
if (WideString == NULL)
return NULL;
MultiByteToWideChar(CP_ACP,
0,
NarrowString,
-1,
WideString,
WideLen);
return WideString;
}
static
BOOL
ParseIpv4Address(
_In_ PCSTR AddressString,
_Out_ PIN_ADDR pAddress)
{
PCSTR pTerminator = NULL;
NTSTATUS Status;
Status = RtlIpv4StringToAddressA(AddressString,
TRUE,
&pTerminator,
pAddress);
if (NT_SUCCESS(Status) && pTerminator != NULL && *pTerminator == '\0')
return TRUE;
return FALSE;
}
static
BOOL
ParseIpv6Address(
_In_ LPCSTR AddressString,
_Out_ PIN6_ADDR pAddress)
{
PCSTR pTerminator = NULL;
NTSTATUS Status;
Status = RtlIpv6StringToAddressA(AddressString,
&pTerminator,
pAddress);
if (NT_SUCCESS(Status) && pTerminator != NULL && *pTerminator == '\0')
return TRUE;
return FALSE;
}
static
VOID
AddIpv4HostEntries(
PWSTR pszHostName,
PIN_ADDR pAddress)
{
DNS_RECORDW ARecord, PtrRecord;
WCHAR szReverseName[32];
/* Prepare the A record */
ZeroMemory(&ARecord, sizeof(DNS_RECORDW));
ARecord.pName = pszHostName;
ARecord.wType = DNS_TYPE_A;
ARecord.wDataLength = sizeof(DNS_A_DATA);
ARecord.Flags.S.Section = DnsSectionAnswer;
ARecord.Flags.S.CharSet = DnsCharSetUnicode;
ARecord.dwTtl = 86400;
ARecord.Data.A.IpAddress = pAddress->S_un.S_addr;
/* Prepare the PTR record */
swprintf(szReverseName,
L"%u.%u.%u.%u.in-addr.arpa.",
pAddress->S_un.S_un_b.s_b4,
pAddress->S_un.S_un_b.s_b3,
pAddress->S_un.S_un_b.s_b2,
pAddress->S_un.S_un_b.s_b1);
ZeroMemory(&PtrRecord, sizeof(DNS_RECORDW));
PtrRecord.pName = szReverseName;
PtrRecord.wType = DNS_TYPE_PTR;
PtrRecord.wDataLength = sizeof(DNS_PTR_DATA);
PtrRecord.Flags.S.Section = DnsSectionAnswer;
PtrRecord.Flags.S.CharSet = DnsCharSetUnicode;
PtrRecord.dwTtl = 86400;
PtrRecord.Data.PTR.pNameHost = pszHostName;
DnsIntCacheAddEntry(&ARecord, TRUE);
DnsIntCacheAddEntry(&PtrRecord, TRUE);
}
static
VOID
AddIpv6HostEntries(
PWSTR pszHostName,
PIN6_ADDR pAddress)
{
DNS_RECORDW AAAARecord, PtrRecord;
WCHAR szReverseName[80];
DWORD i, j, k;
/* Prepare the AAAA record */
ZeroMemory(&AAAARecord, sizeof(DNS_RECORDW));
AAAARecord.pName = pszHostName;
AAAARecord.wType = DNS_TYPE_AAAA;
AAAARecord.wDataLength = sizeof(DNS_AAAA_DATA);
AAAARecord.Flags.S.Section = DnsSectionAnswer;
AAAARecord.Flags.S.CharSet = DnsCharSetUnicode;
AAAARecord.dwTtl = 86400;
CopyMemory(&AAAARecord.Data.AAAA.Ip6Address,
&pAddress->u.Byte,
sizeof(IN6_ADDR));
/* Prepare the PTR record */
ZeroMemory(szReverseName, sizeof(szReverseName));
for (i = 0; i < sizeof(IN6_ADDR); i++)
{
j = 4 * i;
k = sizeof(IN6_ADDR) - 1 - i;
szReverseName[j] = szHexChar[pAddress->u.Byte[k] & 0xF];
szReverseName[j + 1] = L'.';
szReverseName[j + 2] = szHexChar[(pAddress->u.Byte[k] >> 4) & 0xF];
szReverseName[j + 3] = L'.';
}
wcscat(szReverseName, L"ip6.arpa.");
ZeroMemory(&PtrRecord, sizeof(DNS_RECORDW));
PtrRecord.pName = szReverseName;
PtrRecord.wType = DNS_TYPE_PTR;
PtrRecord.wDataLength = sizeof(DNS_PTR_DATA);
PtrRecord.Flags.S.Section = DnsSectionAnswer;
PtrRecord.Flags.S.CharSet = DnsCharSetUnicode;
PtrRecord.dwTtl = 86400;
PtrRecord.Data.PTR.pNameHost = pszHostName;
DnsIntCacheAddEntry(&AAAARecord, TRUE);
DnsIntCacheAddEntry(&PtrRecord, TRUE);
}
static
FILE *
OpenHostsFile(VOID)
{
PWSTR ExpandedPath;
PWSTR DatabasePath;
HKEY DatabaseKey;
DWORD RegSize = 0;
size_t StringLength;
FILE *pHostsFile;
DWORD dwError;
ExpandedPath = HeapAlloc(GetProcessHeap(), 0, MAX_PATH * sizeof(WCHAR));
if (ExpandedPath == NULL)
return NULL;
/* Open the database path key */
dwError = RegOpenKeyExW(HKEY_LOCAL_MACHINE,
L"System\\CurrentControlSet\\Services\\Tcpip\\Parameters",
0,
KEY_READ,
&DatabaseKey);
if (dwError == ERROR_SUCCESS)
{
/* Read the actual path */
RegQueryValueExW(DatabaseKey,
L"DatabasePath",
NULL,
NULL,
NULL,
&RegSize);
DatabasePath = HeapAlloc(GetProcessHeap(), 0, RegSize);
if (DatabasePath == NULL)
{
HeapFree(GetProcessHeap(), 0, ExpandedPath);
RegCloseKey(DatabaseKey);
return NULL;
}
/* Read the actual path */
dwError = RegQueryValueExW(DatabaseKey,
L"DatabasePath",
NULL,
NULL,
(LPBYTE)DatabasePath,
&RegSize);
/* Close the key */
RegCloseKey(DatabaseKey);
if (dwError != ERROR_SUCCESS)
{
HeapFree(GetProcessHeap(), 0, DatabasePath);
HeapFree(GetProcessHeap(), 0, ExpandedPath);
return NULL;
}
/* Expand the name */
ExpandEnvironmentStringsW(DatabasePath, ExpandedPath, MAX_PATH);
HeapFree(GetProcessHeap(), 0, DatabasePath);
}
else
{
/* Use defalt path */
GetSystemDirectoryW(ExpandedPath, MAX_PATH);
StringCchLengthW(ExpandedPath, MAX_PATH, &StringLength);
if (ExpandedPath[StringLength - 1] != L'\\')
{
/* It isn't, so add it ourselves */
StringCchCatW(ExpandedPath, MAX_PATH, L"\\");
}
StringCchCatW(ExpandedPath, MAX_PATH, L"drivers\\etc\\");
}
/* Make sure that the path is backslash-terminated */
StringCchLengthW(ExpandedPath, MAX_PATH, &StringLength);
if (ExpandedPath[StringLength - 1] != L'\\')
{
/* It isn't, so add it ourselves */
StringCchCatW(ExpandedPath, MAX_PATH, L"\\");
}
/* Add the database name */
StringCchCatW(ExpandedPath, MAX_PATH, L"hosts");
/* Open the hosts file */
pHostsFile = _wfopen(ExpandedPath, L"r");
HeapFree(GetProcessHeap(), 0, ExpandedPath);
return pHostsFile;
}
BOOL
ReadHostsFile(VOID)
{
CHAR szLineBuffer[512];
FILE *pHostFile = NULL;
CHAR *Ptr, *NameStart, *NameEnd, *AddressStart, *AddressEnd;
struct in_addr Ipv4Address;
struct in6_addr Ipv6Address;
PWSTR pszHostName;
pHostFile = OpenHostsFile();
if (pHostFile == NULL)
return FALSE;
for (;;)
{
/* Read a line */
if (fgets(szLineBuffer, sizeof(szLineBuffer), pHostFile) == NULL)
break;
NameStart = NameEnd = NULL;
AddressStart = AddressEnd = NULL;
/* Search for the start of the ip address */
Ptr = szLineBuffer;
for (;;)
{
if (*Ptr == 0 || *Ptr == '#')
break;
if (!isspace(*Ptr))
{
AddressStart = Ptr;
Ptr = Ptr + 1;
break;
}
Ptr = Ptr + 1;
}
/* Search for the end of the ip address */
for (;;)
{
if (*Ptr == 0 || *Ptr == '#')
break;
if (isspace(*Ptr))
{
AddressEnd = Ptr;
Ptr = Ptr + 1;
break;
}
Ptr = Ptr + 1;
}
/* Search for the start of the name */
for (;;)
{
if (*Ptr == 0 || *Ptr == '#')
break;
if (!isspace(*Ptr))
{
NameStart = Ptr;
Ptr = Ptr + 1;
break;
}
Ptr = Ptr + 1;
}
/* Search for the end of the name */
for (;;)
{
if (*Ptr == 0 || *Ptr == '#')
break;
if (isspace(*Ptr))
{
NameEnd = Ptr;
break;
}
Ptr = Ptr + 1;
}
if (AddressStart == NULL || AddressEnd == NULL ||
NameStart == NULL || NameEnd == NULL)
continue;
*AddressEnd = 0;
*NameEnd = 0;
DPRINT("%s ==> %s\n", NameStart, AddressStart);
if (ParseIpv4Address(AddressStart, &Ipv4Address))
{
DPRINT("IPv4: %s\n", AddressStart);
pszHostName = AnsiToUnicode(NameStart);
if (pszHostName != NULL)
{
AddIpv4HostEntries(pszHostName, &Ipv4Address);
HeapFree(GetProcessHeap(), 0, pszHostName);
}
}
else if (ParseIpv6Address(AddressStart, &Ipv6Address))
{
DPRINT("IPv6: %s\n", AddressStart);
pszHostName = AnsiToUnicode(NameStart);
if (pszHostName != NULL)
{
AddIpv6HostEntries(pszHostName, &Ipv6Address);
HeapFree(GetProcessHeap(), 0, pszHostName);
}
}
}
fclose(pHostFile);
return TRUE;
}
/* EOF */