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856 lines
21 KiB
856 lines
21 KiB
/*++
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Copyright (c) 1998, Microsoft Corporation
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Module Name:
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dhcpauto.c
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Abstract:
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This module contains code for automatic selection of a client address
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from a given scope of addresses.
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It makes use of a hashing function which accounts for the client's
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hardware address.
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Author:
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Abolade Gbadegesin (aboladeg) 9-Mar-1998
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Revision History:
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Raghu Gatta (rgatta) 5-Jul-2001
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+Changed DhcpIsReservedAddress & DhcpQueryReservedAddress to
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handle variable length name strings.
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+Added DhcpConvertHostNametoUnicode (mimics DhcpServer effect)
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Raghu Gatta (rgatta) 17-Jul-2001
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+Added DhcpGetLocalMacAddr
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--*/
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#include "precomp.h"
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#pragma hdrstop
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ULONG
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DhcpAcquireUniqueAddress(
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PCHAR Name,
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ULONG NameLength,
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PUCHAR HardwareAddress,
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ULONG HardwareAddressLength
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)
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/*++
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Routine Description:
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This routine is invoked to acquire a unique address for a client
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using the given hardware address to decrease the likelihood of collision.
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Arguments:
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Name - the name of the host for whom the address is being requested.
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If this matches the name of a server in the shared-access server-list,
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the address reserved for the server is returned.
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NameLength - length of 'Name', excluding any terminating 'nul'.
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HardwareAddress - the hardware address to be used
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HardwareAddressLength - the length of the hardware address
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Return Value:
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ULONG - the generated IP address
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Environment:
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Invoked from an arbitrary context.
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--*/
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{
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ULONG AssignedAddress;
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ULONG i = 0;
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PLIST_ENTRY Link;
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ULONG ScopeMask;
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ULONG ScopeNetwork;
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ULONG Seed = GetTickCount();
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BOOLEAN bUnused;
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PROFILE("DhcpAcquireUniqueAddress");
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EnterCriticalSection(&DhcpGlobalInfoLock);
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if (Name &&
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(AssignedAddress = DhcpQueryReservedAddress(Name, NameLength))) {
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LeaveCriticalSection(&DhcpGlobalInfoLock);
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NhTrace(
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TRACE_FLAG_DHCP,
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"DhcpAcquireUniqueAddress: returning mapping to %s",
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INET_NTOA(AssignedAddress)
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);
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return AssignedAddress;
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}
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ScopeNetwork = DhcpGlobalInfo->ScopeNetwork;
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ScopeMask = DhcpGlobalInfo->ScopeMask;
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LeaveCriticalSection(&DhcpGlobalInfoLock);
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do {
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if (++i > 4) { AssignedAddress = 0; break; }
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//
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// Generate an address
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//
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do {
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AssignedAddress =
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DhcpGenerateAddress(
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&Seed,
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HardwareAddress,
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HardwareAddressLength,
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ScopeNetwork,
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ScopeMask
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);
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} while(
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(AssignedAddress & ~ScopeMask) == 0 ||
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(AssignedAddress & ~ScopeMask) == ~ScopeMask
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);
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} while(!DhcpIsUniqueAddress(AssignedAddress, &bUnused, NULL, NULL));
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return AssignedAddress;
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} // DhcpAcquireUniqueAddress
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ULONG
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DhcpGenerateAddress(
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PULONG Seed,
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PUCHAR HardwareAddress,
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ULONG HardwareAddressLength,
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ULONG ScopeNetwork,
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ULONG ScopeMask
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)
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/*++
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Routine Description:
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This routine is invoked to compute a randomized hash value
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for a client IP address using a hardware-address.
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Arguments:
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Seed - contains (and receives) the seed to 'RtlRandom'
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HardwareAddress - the hardware address to be used
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HardwareAddressLength - the length of the hardware address
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ScopeNetwork - the network into which the generated address
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will be constrained
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ScopeMask - the mask for the scope network
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Return Value:
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ULONG - the generated IP address
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Environment:
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Invoked from an arbitrary context.
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Revision History:
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Based on 'GrandHashing' from net\sockets\tcpcmd\dhcpm\client\dhcp
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by RameshV.
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--*/
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{
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ULONG Hash;
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ULONG Shift;
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#if 1
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Hash = RtlRandom(Seed) & 0xffff0000;
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Hash |= RtlRandom(Seed) >> 16;
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#else
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Seed = GetTickCount();
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Seed = Seed * 1103515245 + 12345;
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Hash = (Seed) >> 16;
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Hash <<= 16;
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Seed = Seed * 1103515245 + 12345;
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Hash += Seed >> 16;
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#endif
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Shift = Hash % sizeof(ULONG);
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while(HardwareAddressLength--) {
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Hash += (*HardwareAddress++) << (8 * Shift);
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Shift = (Shift + 1) % sizeof(ULONG);
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}
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return (Hash & ~ScopeMask) | ScopeNetwork;
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} // DnsGenerateAddress
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BOOLEAN
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DhcpIsReservedAddress(
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ULONG Address,
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PCHAR Name OPTIONAL,
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ULONG NameLength OPTIONAL
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)
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/*++
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Routine Description:
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This routine is invoked to determine whether the given IP address
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is reserved for another client.
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Arguments:
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Address - the IP address to be determined
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Name - optionally specifies the client on whose behalf the call is made
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NameLength - specifies the length of 'Name' excluding the terminating nul
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Return Value:
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BOOLEAN - TRUE if the address is reserved for another client,
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FALSE otherwise.
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Environment:
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Invoked with 'DhcpGlobalInfoLock' held by the caller.
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--*/
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{
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ULONG Error = NO_ERROR;
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PLIST_ENTRY Link;
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PNAT_DHCP_RESERVATION Reservation;
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PWCHAR pszUnicodeHostName = NULL;
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EnterCriticalSection(&NhLock);
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if (IsListEmpty(&NhDhcpReservationList)) {
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LeaveCriticalSection(&NhLock);
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return FALSE;
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}
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if (Name) {
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Error = DhcpConvertHostNametoUnicode(
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CP_OEMCP, // atleast Windows clients send it this way
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Name,
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NameLength,
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&pszUnicodeHostName
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);
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if (NO_ERROR != Error) {
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LeaveCriticalSection(&NhLock);
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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//
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// we can return true or false on failure
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// better we return false - otherwise the client will be in a continuous
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// loop trying to get another address when we NACK its request
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//
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return FALSE;
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}
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}
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for (Link = NhDhcpReservationList.Flink;
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Link != &NhDhcpReservationList; Link = Link->Flink) {
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Reservation = CONTAINING_RECORD(Link, NAT_DHCP_RESERVATION, Link);
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if (Address == Reservation->Address) {
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if (lstrcmpiW(pszUnicodeHostName, Reservation->Name)) {
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LeaveCriticalSection(&NhLock);
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return TRUE;
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} else {
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LeaveCriticalSection(&NhLock);
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return FALSE;
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}
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} else if (lstrcmpiW(pszUnicodeHostName, Reservation->Name) == 0 &&
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Address != Reservation->Address) {
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LeaveCriticalSection(&NhLock);
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return TRUE;
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}
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}
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LeaveCriticalSection(&NhLock);
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return FALSE;
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} // DhcpIsReservedAddress
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BOOLEAN
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DhcpIsUniqueAddress(
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ULONG Address,
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PBOOLEAN IsLocal,
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PUCHAR ConflictAddress OPTIONAL,
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PULONG ConflictAddressLength OPTIONAL
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)
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/*++
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Routine Description:
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This routine is invoked to determine whether the given address
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is unique on the directly connected subnetworks.
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The determination accounts for any configured static addresses
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included in the global information.
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Arguments:
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Address - the address whose uniqueness is to be determined
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IsLocal - pointer to BOOLEAN which receives info about whether
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the requested address is one of the local interfaces' address
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ConflictAddress - optionally receives a copy of the conflicting
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hardware address if a conflict is found
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ConflictAddressLength - if 'ConflictAddress' is set, receives
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the length of the conflicting address.
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Return Value:
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BOOLEAN - TRUE if unique, FALSE otherwise.
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--*/
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{
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BOOLEAN ConflictFound = FALSE;
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ULONG Error;
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UCHAR ExistingAddress[MAX_HARDWARE_ADDRESS_LENGTH];
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ULONG ExistingAddressLength;
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ULONG i;
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PDHCP_INTERFACE Interfacep;
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BOOLEAN IsNatInterface;
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PLIST_ENTRY Link;
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ULONG SourceAddress;
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PROFILE("DhcpIsUniqueAddress");
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*IsLocal = FALSE;
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//
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// See if this is a static address
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//
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EnterCriticalSection(&DhcpGlobalInfoLock);
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if (DhcpGlobalInfo && DhcpGlobalInfo->ExclusionCount) {
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for (i = 0; i < DhcpGlobalInfo->ExclusionCount; i++) {
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if (Address == DhcpGlobalInfo->ExclusionArray[i]) {
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LeaveCriticalSection(&DhcpGlobalInfoLock);
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if (ConflictAddressLength) { *ConflictAddressLength = 0; }
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return FALSE;
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}
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}
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}
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LeaveCriticalSection(&DhcpGlobalInfoLock);
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//
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// Try to detect collisions
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//
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EnterCriticalSection(&DhcpInterfaceLock);
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for (Link = DhcpInterfaceList.Flink;
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Link != &DhcpInterfaceList;
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Link = Link->Flink
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) {
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Interfacep = CONTAINING_RECORD(Link, DHCP_INTERFACE, Link);
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if (DHCP_INTERFACE_DELETED(Interfacep)) { continue; }
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ACQUIRE_LOCK(Interfacep);
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//
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// We send out an ARP request unless
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// (a) the interface is a boundary interface
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// (b) the interface is not NAT-enabled
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// (c) the allocator is not active on the interface
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// (d) the interface is not a LAN adapter
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// (e) the interface has no bindings.
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//
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if (!DHCP_INTERFACE_NAT_NONBOUNDARY(Interfacep) ||
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!DHCP_INTERFACE_ACTIVE(Interfacep) ||
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(Interfacep->Type != PERMANENT) ||
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!Interfacep->BindingCount) {
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RELEASE_LOCK(Interfacep);
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continue;
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}
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for (i = 0; i < Interfacep->BindingCount; i++) {
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SourceAddress = Interfacep->BindingArray[i].Address;
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ExistingAddressLength = sizeof(ExistingAddress);
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if (SourceAddress == Address)
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{
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//
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// check to see that requested address is not same as
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// one of the local addresses on the NAT box
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//
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NhTrace(
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TRACE_FLAG_DHCP,
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"DhcpIsUniqueAddress: %s is in use locally",
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INET_NTOA(Address)
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);
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if (ConflictAddress) {
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if (DhcpGetLocalMacAddr(
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Address,
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ExistingAddress,
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&ExistingAddressLength
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))
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{
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if (ExistingAddressLength > MAX_HARDWARE_ADDRESS_LENGTH) {
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ExistingAddressLength = MAX_HARDWARE_ADDRESS_LENGTH;
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}
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CopyMemory(
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ConflictAddress,
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ExistingAddress,
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ExistingAddressLength
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);
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*ConflictAddressLength = ExistingAddressLength;
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}
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else
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{
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*ConflictAddressLength = 0;
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}
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}
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*IsLocal = TRUE;
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ConflictFound = TRUE;
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break;
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}
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RELEASE_LOCK(Interfacep);
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Error =
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SendARP(
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Address,
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SourceAddress,
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(PULONG)ExistingAddress,
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&ExistingAddressLength
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);
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ACQUIRE_LOCK(Interfacep);
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if (Error) {
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NhWarningLog(
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IP_AUTO_DHCP_LOG_SENDARP_FAILED,
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Error,
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"%I%I",
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Address,
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SourceAddress
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);
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} else if (ExistingAddressLength &&
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ExistingAddressLength <= sizeof(ExistingAddress)) {
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NhTrace(
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TRACE_FLAG_DHCP,
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"DhcpIsUniqueAddress: %s is in use",
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INET_NTOA(Address)
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);
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#if DBG
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NhDump(
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TRACE_FLAG_DHCP,
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ExistingAddress,
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ExistingAddressLength,
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1
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);
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#endif
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if (ConflictAddress) {
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if (ExistingAddressLength > MAX_HARDWARE_ADDRESS_LENGTH) {
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ExistingAddressLength = MAX_HARDWARE_ADDRESS_LENGTH;
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}
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CopyMemory(
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ConflictAddress,
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ExistingAddress,
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ExistingAddressLength
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);
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*ConflictAddressLength = ExistingAddressLength;
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}
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ConflictFound = TRUE;
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break;
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}
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}
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RELEASE_LOCK(Interfacep);
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if (ConflictFound) { break; }
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}
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LeaveCriticalSection(&DhcpInterfaceLock);
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return ConflictFound ? FALSE : TRUE;
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} // DhcpIsUniqueAddress
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ULONG
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DhcpQueryReservedAddress(
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PCHAR Name,
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ULONG NameLength
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)
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/*++
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Routine Description:
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This routine is called to determine whether the given machine name
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corresponds to an entry in the list of reserved addresses.
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Arguments:
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Name - specifies the machine name, which might not be nul-terminated.
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NameLength - specifies the length of the given machine name,
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not including any terminating nul character.
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Return Value:
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ULONG - the IP address of the machine, if any.
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Environment:
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Invoked with 'DhcpGlobalInfoLock' held by the caller.
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--*/
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{
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ULONG Error = NO_ERROR;
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PLIST_ENTRY Link;
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ULONG ReservedAddress;
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PNAT_DHCP_RESERVATION Reservation;
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PWCHAR pszUnicodeHostName = NULL;
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|
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EnterCriticalSection(&NhLock);
|
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if (IsListEmpty(&NhDhcpReservationList))
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{
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LeaveCriticalSection(&NhLock);
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return FALSE;
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}
|
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if (Name) {
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Error = DhcpConvertHostNametoUnicode(
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CP_OEMCP, // atleast Windows clients send it this way
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Name,
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NameLength,
|
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&pszUnicodeHostName
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);
|
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if (NO_ERROR != Error) {
|
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LeaveCriticalSection(&NhLock);
|
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return FALSE;
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}
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}
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for (Link = NhDhcpReservationList.Flink;
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Link != &NhDhcpReservationList; Link = Link->Flink)
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{
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Reservation = CONTAINING_RECORD(Link, NAT_DHCP_RESERVATION, Link);
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if (lstrcmpiW(pszUnicodeHostName, Reservation->Name)) { continue; }
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ReservedAddress = Reservation->Address;
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LeaveCriticalSection(&NhLock);
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return ReservedAddress;
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}
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LeaveCriticalSection(&NhLock);
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|
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if (pszUnicodeHostName) {
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NH_FREE(pszUnicodeHostName);
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}
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return 0;
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} // DhcpQueryReservedAddress
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|
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//
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// Utility routines
|
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//
|
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|
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ULONG
|
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DhcpConvertHostNametoUnicode(
|
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UINT CodePage,
|
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CHAR *pHostName,
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ULONG HostNameLength,
|
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PWCHAR *ppszUnicode
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)
|
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{
|
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//
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// make sure to free the returned Unicode hostname
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//
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DWORD dwSize = 0;
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ULONG Error = NO_ERROR;
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PCHAR pszHostName = NULL;
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LPBYTE pszUtf8HostName = NULL; // copy of pszHostName in Utf8 format
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PWCHAR pszUnicodeHostName = NULL;
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|
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if (ppszUnicode)
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{
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*ppszUnicode = NULL;
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}
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else
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{
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return ERROR_INVALID_PARAMETER;
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}
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do
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{
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//
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// create a null terminated copy
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//
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dwSize = HostNameLength + 4;
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pszHostName = reinterpret_cast<PCHAR>(NH_ALLOCATE(dwSize));
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|
if (!pszHostName)
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|
{
|
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NhTrace(
|
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TRACE_FLAG_DNS,
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|
"DhcpConvertHostNametoUnicode: allocation failed for "
|
|
"hostname copy buffer"
|
|
);
|
|
break;
|
|
}
|
|
ZeroMemory(pszHostName, dwSize);
|
|
memcpy(pszHostName, pHostName, HostNameLength);
|
|
pszHostName[HostNameLength] = '\0';
|
|
|
|
//
|
|
// convert the given hostname to a Unicode string
|
|
//
|
|
|
|
if (CP_UTF8 == CodePage)
|
|
{
|
|
pszUtf8HostName = (LPBYTE)pszHostName;
|
|
}
|
|
else
|
|
{
|
|
//
|
|
// now convert this into UTF8 format
|
|
//
|
|
if (!ConvertToUtf8(
|
|
CodePage,
|
|
(LPSTR)pszHostName,
|
|
(PCHAR *)&pszUtf8HostName,
|
|
&dwSize))
|
|
{
|
|
Error = GetLastError();
|
|
NhTrace(
|
|
TRACE_FLAG_DNS,
|
|
"DhcpConvertHostNametoUnicode: conversion from "
|
|
"CodePage %d to UTF8 for hostname failed "
|
|
"with error %ld (0x%08x)",
|
|
CodePage,
|
|
Error,
|
|
Error
|
|
);
|
|
break;
|
|
}
|
|
}
|
|
|
|
//
|
|
// now convert UTF8 string into Unicode format
|
|
//
|
|
if (!ConvertUTF8ToUnicode(
|
|
pszUtf8HostName,
|
|
(LPWSTR *)&pszUnicodeHostName,
|
|
&dwSize))
|
|
{
|
|
Error = GetLastError();
|
|
NhTrace(
|
|
TRACE_FLAG_DNS,
|
|
"DhcpConvertHostNametoUnicode: conversion from "
|
|
"UTF8 to Unicode for hostname failed "
|
|
"with error %ld (0x%08x)",
|
|
Error,
|
|
Error
|
|
);
|
|
if (pszUnicodeHostName)
|
|
{
|
|
NH_FREE(pszUnicodeHostName);
|
|
}
|
|
break;
|
|
}
|
|
|
|
*ppszUnicode = pszUnicodeHostName;
|
|
|
|
NhTrace(
|
|
TRACE_FLAG_DNS,
|
|
"DhcpConvertHostNametoUnicode: succeeded! %S",
|
|
pszUnicodeHostName
|
|
);
|
|
|
|
} while (FALSE);
|
|
|
|
if (pszHostName)
|
|
{
|
|
NH_FREE(pszHostName);
|
|
}
|
|
|
|
if ((CP_UTF8 != CodePage) && pszUtf8HostName)
|
|
{
|
|
NH_FREE(pszUtf8HostName);
|
|
}
|
|
|
|
return Error;
|
|
|
|
} // DhcpConvertHostNametoUnicode
|
|
|
|
BOOL
|
|
DhcpGetLocalMacAddr(
|
|
ULONG Address,
|
|
PUCHAR MacAddr,
|
|
PULONG MacAddrLength
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine is invoked to determine the local physical MAC address
|
|
for the given local IP address.
|
|
|
|
Arguments:
|
|
|
|
Address - the local IP address
|
|
|
|
MacAddr - buffer for holding the MAC addr (upto MAX_HARDWARE_ADDRESS_LENGTH)
|
|
|
|
MacAddrLength - specifies the length of 'MacAddr'
|
|
|
|
Return Value:
|
|
|
|
BOOLEAN - TRUE if we are able to get the MAC address,
|
|
FALSE otherwise.
|
|
|
|
Environment:
|
|
|
|
Invoked from DhcpIsUniqueAddress().
|
|
|
|
--*/
|
|
|
|
{
|
|
BOOL bRet = FALSE;
|
|
DWORD Error = NO_ERROR;
|
|
PMIB_IPNETTABLE IpNetTable = NULL;
|
|
PMIB_IPNETROW IpNetRow = NULL;
|
|
DWORD dwPhysAddrLen = 0, i;
|
|
ULONG dwSize = 0;
|
|
|
|
do
|
|
{
|
|
//
|
|
// retrieve size of address mapping table
|
|
//
|
|
Error = GetIpNetTable(
|
|
IpNetTable,
|
|
&dwSize,
|
|
FALSE
|
|
);
|
|
|
|
if (!Error)
|
|
{
|
|
NhTrace(
|
|
TRACE_FLAG_DHCP,
|
|
"DhcpGetLocalMacAddr: should NOT have returned %d",
|
|
Error
|
|
);
|
|
break;
|
|
}
|
|
else
|
|
if (ERROR_INSUFFICIENT_BUFFER != Error)
|
|
{
|
|
NhTrace(
|
|
TRACE_FLAG_DHCP,
|
|
"DhcpGetLocalMacAddr: GetIpNetTable=%d",
|
|
Error
|
|
);
|
|
break;
|
|
}
|
|
|
|
//
|
|
// allocate a buffer
|
|
//
|
|
IpNetTable = (PMIB_IPNETTABLE)NH_ALLOCATE(dwSize);
|
|
|
|
if (!IpNetTable)
|
|
{
|
|
NhTrace(
|
|
TRACE_FLAG_DHCP,
|
|
"DhcpGetLocalMacAddr: error allocating %d bytes",
|
|
dwSize
|
|
);
|
|
break;
|
|
}
|
|
|
|
//
|
|
// retrieve the address mapping table
|
|
//
|
|
Error = GetIpNetTable(
|
|
IpNetTable,
|
|
&dwSize,
|
|
FALSE
|
|
);
|
|
|
|
if (NO_ERROR != Error)
|
|
{
|
|
NhTrace(
|
|
TRACE_FLAG_DHCP,
|
|
"DhcpGetLocalMacAddr: GetIpNetTable=%d size=%d",
|
|
Error,
|
|
dwSize
|
|
);
|
|
break;
|
|
}
|
|
|
|
for (i = 0; i < IpNetTable->dwNumEntries; i++)
|
|
{
|
|
IpNetRow = &IpNetTable->table[i];
|
|
|
|
if (IpNetRow->dwAddr == Address)
|
|
{
|
|
dwPhysAddrLen = IpNetRow->dwPhysAddrLen;
|
|
if (dwPhysAddrLen > MAX_HARDWARE_ADDRESS_LENGTH)
|
|
{
|
|
dwPhysAddrLen = MAX_HARDWARE_ADDRESS_LENGTH;
|
|
}
|
|
CopyMemory(
|
|
MacAddr,
|
|
IpNetRow->bPhysAddr,
|
|
dwPhysAddrLen
|
|
);
|
|
*MacAddrLength = dwPhysAddrLen;
|
|
bRet = TRUE;
|
|
break;
|
|
}
|
|
}
|
|
|
|
} while (FALSE);
|
|
|
|
if (IpNetTable)
|
|
{
|
|
NH_FREE(IpNetTable);
|
|
}
|
|
|
|
return bRet;
|
|
} // DhcpGetLocalMacAddr
|