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2050 lines
62 KiB
2050 lines
62 KiB
/*++
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Copyright (c) 1997 Microsoft Corporation
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Module Name:
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icmp.c
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Abstract:
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This module contains the code for manipulating ICMP request/reply mappings.
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When the NAT decides to translate an ICMP request, it creates a mapping
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and places it on the interface's ICMP-mapping list, so that when the reply
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to the request arrives, it can be directed to the appropriate client.
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Author:
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Abolade Gbadegesin (t-abolag) 31-July-1997
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Revision History:
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--*/
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#include "precomp.h"
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#pragma hdrstop
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//
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// GLOBAL DATA DECLARATIONS
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//
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NPAGED_LOOKASIDE_LIST IcmpLookasideList;
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LIST_ENTRY IcmpMappingList[NatMaximumDirection];
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KSPIN_LOCK IcmpMappingLock;
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//
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// FORWARD DECLARATIONS
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//
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FORWARD_ACTION
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NatpFirewallIcmp(
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PNAT_INTERFACE Interfacep,
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IP_NAT_DIRECTION Direction,
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PNAT_XLATE_CONTEXT Contextp
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);
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BOOLEAN
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NatTranslateIcmpEncapsulatedRequest(
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PNAT_INTERFACE Interfacep OPTIONAL,
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IP_NAT_DIRECTION Direction,
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PIP_HEADER IpHeader,
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PICMP_HEADER IcmpHeader,
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PIP_HEADER EncapsulatedIpHeader,
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struct _ENCAPSULATED_ICMP_HEADER* EncapsulatedIcmpHeader,
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BOOLEAN ChecksumOffloaded
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);
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BOOLEAN
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NatTranslateIcmpRequest(
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PNAT_INTERFACE Interfacep OPTIONAL,
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IP_NAT_DIRECTION Direction,
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PNAT_XLATE_CONTEXT Contextp,
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BOOLEAN ReplyCode,
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BOOLEAN ChecksumOffloaded
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);
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BOOLEAN
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NatTranslateEncapsulatedRequest(
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PNAT_INTERFACE Interfacep OPTIONAL,
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IP_NAT_DIRECTION Direction,
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PIP_HEADER IpHeader,
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PICMP_HEADER IcmpHeader,
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PIP_HEADER EncapsulatedIpHeader,
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struct _ENCAPSULATED_UDP_HEADER* EncapsulatedHeader,
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BOOLEAN ChecksumOffloaded
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);
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NTSTATUS
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NatCreateIcmpMapping(
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PNAT_INTERFACE Interfacep,
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ULONG RemoteAddress,
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ULONG PrivateAddress,
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ULONG PublicAddress,
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PUSHORT PrivateId,
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PUSHORT PublicId,
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PLIST_ENTRY InboundInsertionPoint,
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PLIST_ENTRY OutboundInsertionPoint,
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PNAT_ICMP_MAPPING* MappingCreated
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)
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/*++
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Routine Description:
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Called to create, initialize, and insert an ICMP mapping in an interface's
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list of ICMP mappings.
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For outbound ICMP requests, we allocate a unique 'PublicId' for the mapping,
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and for inbound requests, we allocate a unique 'PrivateId' for the mapping.
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Arguments:
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Interfacep - the interface for the new mapping
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RemoteAddress - the address of the remote endpoint
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PrivateAddress - the address of the machine on the private network
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PublicAddress - the publicly-visible address to replace 'PrivateAddress';
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in case this is 0, an address is chosen in this routine.
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PrivateId - the private-endpoint's identifier for the ICMP message,
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or NULL if an identifier should be chosen by this routine.
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PublicId - the public-endpoint's identifier for the ICMP message,
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or NULL if an identifier should be chosen by this routine.
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InboundInsertionPoint - the entry preceding the new mapping in the list
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sorted for inbound searching
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OutboundInsertionPoint - the entry preceding the new mapping in the list
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sorted for outbound searching
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MappingCreated - receives the mapping created
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Return Value:
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NTSTATUS - indicates success/failure
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Environment:
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Invoked with 'IcmpMappingLock' held by the caller.
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--*/
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{
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USHORT Id;
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PLIST_ENTRY Link;
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PNAT_ICMP_MAPPING Mapping;
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PNAT_ICMP_MAPPING DuplicateMapping;
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NTSTATUS status;
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PNAT_ICMP_MAPPING Temp;
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PNAT_USED_ADDRESS UsedAddress;
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CALLTRACE(("NatCreateIcmpMapping\n"));
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//
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// Allocate a new mapping
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//
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Mapping = ALLOCATE_ICMP_BLOCK();
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if (!Mapping) {
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ERROR(("NatCreateIcmpMapping: allocation failed\n"));
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return STATUS_NO_MEMORY;
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}
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//
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// Initialize the mapping
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//
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Mapping->PrivateKey = MAKE_ICMP_KEY(RemoteAddress, PrivateAddress);
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//
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// See if the public address is specified, and if not, acquire an address
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//
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if (PublicAddress) {
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Mapping->PublicKey = MAKE_ICMP_KEY(RemoteAddress, PublicAddress);
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} else {
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//
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// Acquire an address mapping for the ICMP mapping
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//
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KeAcquireSpinLockAtDpcLevel(&Interfacep->Lock);
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status =
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NatAcquireFromAddressPool(
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Interfacep,
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PrivateAddress,
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0,
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&UsedAddress
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);
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if (!NT_SUCCESS(status)) {
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KeReleaseSpinLockFromDpcLevel(&Interfacep->Lock);
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TRACE(ICMP, ("NatCreateIcmpMapping: no address available\n"));
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FREE_ICMP_BLOCK(Mapping);
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return STATUS_UNSUCCESSFUL;
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}
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PublicAddress = UsedAddress->PublicAddress;
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NatDereferenceAddressPoolEntry(Interfacep, UsedAddress);
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KeReleaseSpinLockFromDpcLevel(&Interfacep->Lock);
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Mapping->PublicKey = MAKE_ICMP_KEY(RemoteAddress, PublicAddress);
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}
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//
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// If no 'PrivateId' is specified, select one.
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//
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if (PrivateId) {
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Mapping->PrivateId = *PrivateId;
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} else {
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//
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// Find the next available identifier
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// by searching the list of inbound mappings
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//
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Id = 1;
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for (Link = IcmpMappingList[NatOutboundDirection].Flink;
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Link != &IcmpMappingList[NatOutboundDirection];
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Link = Link->Flink) {
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Temp =
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CONTAINING_RECORD(
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Link, NAT_ICMP_MAPPING, Link[NatOutboundDirection]
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);
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if (Mapping->PrivateKey > Temp->PrivateKey) {
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continue;
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} else if (Mapping->PrivateKey < Temp->PrivateKey) {
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break;
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}
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//
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// Primary key equal; see if the identifier we've chosen
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// collides with this one
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//
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if (Id > Temp->PrivateId) {
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continue;
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} else if (Id < Temp->PrivateId) {
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break;
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}
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//
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// The identifier's collide; choose another and go on
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//
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++Id;
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}
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if (Link == &IcmpMappingList[NatOutboundDirection] && !Id) {
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//
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// We are at the end of the list, and all 64K-1 IDs are taken
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//
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FREE_ICMP_BLOCK(Mapping);
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return STATUS_UNSUCCESSFUL;
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}
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Mapping->PrivateId = Id;
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//
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// And by the way, we now have the outbound insertion point
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//
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if (!OutboundInsertionPoint) { OutboundInsertionPoint = Link; }
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}
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//
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// If no 'PublicId' is specified, select one.
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//
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if (PublicId) {
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Mapping->PublicId = *PublicId;
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} else {
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//
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// Find the next available identifier
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// by searching the list of inbound mappings
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//
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Id = 1;
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for (Link = IcmpMappingList[NatInboundDirection].Flink;
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Link != &IcmpMappingList[NatInboundDirection];
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Link = Link->Flink) {
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Temp =
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CONTAINING_RECORD(
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Link, NAT_ICMP_MAPPING, Link[NatInboundDirection]
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);
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if (Mapping->PublicKey > Temp->PublicKey) {
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continue;
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} else if (Mapping->PublicKey < Temp->PublicKey) {
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break;
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}
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//
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// Primary key equal; see if the identifier we've chosen
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// collides with this one
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//
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if (Id > Temp->PublicId) {
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continue;
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} else if (Id < Temp->PublicId) {
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break;
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}
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//
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// The identifier's collide; choose another and go on
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//
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++Id;
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}
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if (Link == &IcmpMappingList[NatInboundDirection] && !Id) {
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//
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// We are at the end of the list, and all 64K-1 IDs are taken
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//
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FREE_ICMP_BLOCK(Mapping);
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return STATUS_UNSUCCESSFUL;
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}
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Mapping->PublicId = Id;
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//
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// And by the way, we now have the inbound insertion point
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//
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if (!InboundInsertionPoint) { InboundInsertionPoint = Link; }
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}
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TRACE(
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MAPPING,
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("NatCreateIcmpMapping: Icmp=%016I64X:%04X::%016I64X:%04X\n",
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Mapping->PrivateKey, Mapping->PrivateId,
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Mapping->PublicKey, Mapping->PublicId
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));
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//
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// Insert the mapping in the inbound list
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//
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if (!InboundInsertionPoint) {
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DuplicateMapping =
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NatLookupInboundIcmpMapping(
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Mapping->PrivateKey,
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Mapping->PrivateId,
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&InboundInsertionPoint
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);
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if (NULL != DuplicateMapping) {
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//
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// This mapping already exists on the inbound path
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//
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FREE_ICMP_BLOCK(Mapping);
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return STATUS_UNSUCCESSFUL;
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}
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}
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InsertTailList(InboundInsertionPoint, &Mapping->Link[NatInboundDirection]);
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//
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// Insert the mapping in the outbound list
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//
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if (!OutboundInsertionPoint) {
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DuplicateMapping =
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NatLookupOutboundIcmpMapping(
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Mapping->PublicKey,
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Mapping->PublicId,
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&OutboundInsertionPoint
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);
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if (NULL != DuplicateMapping) {
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//
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// This mapping already exists on the outbound path
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//
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RemoveEntryList(&Mapping->Link[NatInboundDirection]);
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FREE_ICMP_BLOCK(Mapping);
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return STATUS_UNSUCCESSFUL;
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}
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}
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InsertTailList(
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OutboundInsertionPoint, &Mapping->Link[NatOutboundDirection]
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);
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*MappingCreated = Mapping;
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return STATUS_SUCCESS;
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} // NatCreateIcmpMapping
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VOID
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NatInitializeIcmpManagement(
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VOID
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)
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/*++
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Routine Description:
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This routine is called to initialize the ICMP translation module.
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Arguments:
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none.
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Return Value:
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none.
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--*/
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{
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CALLTRACE(("NatInitializeIcmpManagement\n"));
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KeInitializeSpinLock(&IcmpMappingLock);
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InitializeListHead(&IcmpMappingList[NatInboundDirection]);
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InitializeListHead(&IcmpMappingList[NatOutboundDirection]);
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ExInitializeNPagedLookasideList(
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&IcmpLookasideList,
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NatAllocateFunction,
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NULL,
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0,
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sizeof(NAT_ICMP_MAPPING),
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NAT_TAG_ICMP,
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ICMP_LOOKASIDE_DEPTH
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);
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} // NatInitializeIcmpManagement
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PNAT_ICMP_MAPPING
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NatLookupInboundIcmpMapping(
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ULONG64 PublicKey,
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USHORT PublicId,
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PLIST_ENTRY* InsertionPoint
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)
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/*++
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Routine Description:
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This routine is called to find an ICMP mapping using the remote-address
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and the publicly-visible address, which correspond to the 'PublicKey',
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and the 'PublicId' field.
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Arguments:
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PublicKey - the remote-address/public-address combination
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PublicId - the mapping's public identifier
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InsertionPoint - receives the insertion-point if the mapping is not found.
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Return Value:
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PNAT_ICMP_MAPPING - the mapping found, or NULL if not found.
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--*/
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{
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PLIST_ENTRY Link;
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PNAT_ICMP_MAPPING Mapping;
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CALLTRACE(("NatLookupInboundIcmpMapping\n"));
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if (InsertionPoint) { *InsertionPoint = NULL; }
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for (Link = IcmpMappingList[NatInboundDirection].Flink;
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Link != &IcmpMappingList[NatInboundDirection]; Link = Link->Flink) {
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Mapping =
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CONTAINING_RECORD(
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Link, NAT_ICMP_MAPPING, Link[NatInboundDirection]
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);
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if (PublicKey > Mapping->PublicKey) {
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continue;
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} else if (PublicKey < Mapping->PublicKey) {
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break;
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}
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//
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// Primary keys equal; check secondary keys.
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//
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if (PublicId > Mapping->PublicId) {
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continue;
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} else if (PublicId < Mapping->PublicId) {
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break;
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}
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//
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// Secondary keys equal, too. This is the requested item.
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//
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return Mapping;
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}
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if (InsertionPoint) { *InsertionPoint = Link; }
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return NULL;
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|
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} // NatLookupInboundIcmpMapping
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|
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|
|
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PNAT_ICMP_MAPPING
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NatLookupOutboundIcmpMapping(
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ULONG64 PrivateKey,
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USHORT PrivateId,
|
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PLIST_ENTRY* InsertionPoint
|
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)
|
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|
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/*++
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|
|
|
Routine Description:
|
|
|
|
This routine is called to find an ICMP mapping using the remote-address
|
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and the private address, which correspond to the 'PrivateKey'.
|
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|
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Arguments:
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|
|
PrivateKey - the remote-address/private-address combination
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|
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PrivateId - the mapping's private identifier
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|
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InsertionPoint - receives insertion-point if mapping not found.
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|
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Return Value:
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PNAT_ICMP_MAPPING - the mapping found, or NULL if not found.
|
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|
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--*/
|
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|
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{
|
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PLIST_ENTRY Link;
|
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PNAT_ICMP_MAPPING Mapping;
|
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CALLTRACE(("NatLookupOutboundIcmpMapping\n"));
|
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|
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if (InsertionPoint) { *InsertionPoint = NULL; }
|
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|
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for (Link = IcmpMappingList[NatOutboundDirection].Flink;
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Link != &IcmpMappingList[NatOutboundDirection]; Link = Link->Flink) {
|
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|
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Mapping =
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CONTAINING_RECORD(
|
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Link, NAT_ICMP_MAPPING, Link[NatOutboundDirection]
|
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);
|
|
|
|
if (PrivateKey > Mapping->PrivateKey) {
|
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continue;
|
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} else if (PrivateKey < Mapping->PrivateKey) {
|
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break;
|
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}
|
|
|
|
//
|
|
// Primary keys equal; check secondary keys.
|
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//
|
|
|
|
if (PrivateId > Mapping->PrivateId) {
|
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continue;
|
|
} else if (PrivateId < Mapping->PrivateId) {
|
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break;
|
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}
|
|
|
|
//
|
|
// Keys are equal, so we've found it.
|
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//
|
|
|
|
return Mapping;
|
|
}
|
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|
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if (InsertionPoint) { *InsertionPoint = Link; }
|
|
|
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return NULL;
|
|
|
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} // NatLookupOutboundIcmpMapping
|
|
|
|
|
|
FORWARD_ACTION
|
|
NatpFirewallIcmp(
|
|
PNAT_INTERFACE Interfacep,
|
|
IP_NAT_DIRECTION Direction,
|
|
PNAT_XLATE_CONTEXT Contextp
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine encapsulates the ICMP firewall logic. It is
|
|
only used (as of now) for non-boundary FW interfaces
|
|
|
|
Arguments:
|
|
|
|
Interfacep - the boundary interface over which to translate.
|
|
|
|
Direction - the direction in which the packet is traveling
|
|
|
|
Contextp - initialized with context-information for the packet
|
|
|
|
Return Value:
|
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|
|
FORWARD_ACTION - indicates action to take on packet.
|
|
|
|
Environment:
|
|
|
|
Invoked with a reference made to 'Interfacep'.
|
|
|
|
--*/
|
|
|
|
{
|
|
FORWARD_ACTION act;
|
|
ULONG i;
|
|
PICMP_HEADER IcmpHeader;
|
|
PIP_HEADER IpHeader;
|
|
PNAT_ICMP_MAPPING IcmpMapping;
|
|
ULONG64 PublicKey;
|
|
ULONG64 RemoteKey;
|
|
PLIST_ENTRY InsertionPoint;
|
|
NTSTATUS ntStatus;
|
|
|
|
TRACE(XLATE, ("NatpFirewallIcmp\n"));
|
|
|
|
if (NatOutboundDirection == Direction) {
|
|
|
|
//
|
|
// Make sure this packet has a valid source address
|
|
// for this interface.
|
|
//
|
|
|
|
act = DROP;
|
|
for (i = 0; i < Interfacep->AddressCount; i++) {
|
|
if (Contextp->SourceAddress ==
|
|
Interfacep->AddressArray[i].Address
|
|
) {
|
|
act = FORWARD;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (DROP == act) {
|
|
|
|
//
|
|
// Invalid source addess -- packet should be
|
|
// dropped w/o any further processing.
|
|
//
|
|
|
|
return act;
|
|
}
|
|
}
|
|
|
|
IpHeader = Contextp->Header;
|
|
IcmpHeader = (PICMP_HEADER)Contextp->ProtocolHeader;
|
|
|
|
switch (IcmpHeader->Type) {
|
|
|
|
//
|
|
// Message forewarded only if a corresponding mapping
|
|
// exists. A mapping for an outbound packet can exist only
|
|
// if the use chooses to allow the corresponding request
|
|
// type.
|
|
//
|
|
|
|
case ICMP_ECHO_REPLY:
|
|
case ICMP_TIMESTAMP_REPLY:
|
|
case ICMP_ROUTER_REPLY:
|
|
case ICMP_MASK_REPLY: {
|
|
|
|
if (NatInboundDirection == Direction) {
|
|
PublicKey =
|
|
MAKE_ICMP_KEY(
|
|
Contextp->SourceAddress,
|
|
Contextp->DestinationAddress
|
|
);
|
|
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
IcmpMapping =
|
|
NatLookupInboundIcmpMapping(
|
|
PublicKey,
|
|
IcmpHeader->Identifier,
|
|
&InsertionPoint
|
|
);
|
|
|
|
if (NULL != IcmpMapping) {
|
|
KeQueryTickCount(
|
|
(PLARGE_INTEGER)&IcmpMapping->LastAccessTime
|
|
);
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
|
|
act = IcmpMapping != NULL ? FORWARD : DROP;
|
|
} else {
|
|
PublicKey =
|
|
MAKE_ICMP_KEY(
|
|
Contextp->DestinationAddress,
|
|
Contextp->SourceAddress
|
|
);
|
|
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
IcmpMapping =
|
|
NatLookupOutboundIcmpMapping(
|
|
PublicKey,
|
|
IcmpHeader->Identifier,
|
|
&InsertionPoint
|
|
);
|
|
|
|
if (NULL != IcmpMapping) {
|
|
KeQueryTickCount(
|
|
(PLARGE_INTEGER)&IcmpMapping->LastAccessTime
|
|
);
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
|
|
act = IcmpMapping != NULL ? FORWARD : DROP;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
//
|
|
// Outbound messages create a mapping and are forwarded.
|
|
// Inbound messages are dropped, unless configured to
|
|
// allow inbound; if this is the case, create a mapping
|
|
// and forward. The mapping will allow the response
|
|
// to go through the firewall
|
|
//
|
|
|
|
case ICMP_ECHO_REQUEST:
|
|
case ICMP_TIMESTAMP_REQUEST:
|
|
case ICMP_ROUTER_REQUEST:
|
|
case ICMP_MASK_REQUEST: {
|
|
|
|
if (NatOutboundDirection == Direction) {
|
|
act = FORWARD;
|
|
|
|
//
|
|
// Check to see if a mapping already exists
|
|
//
|
|
|
|
PublicKey =
|
|
MAKE_ICMP_KEY(
|
|
Contextp->DestinationAddress,
|
|
Contextp->SourceAddress
|
|
);
|
|
|
|
KeAcquireSpinLockAtDpcLevel (&IcmpMappingLock);
|
|
|
|
IcmpMapping =
|
|
NatLookupOutboundIcmpMapping(
|
|
PublicKey,
|
|
IcmpHeader->Identifier,
|
|
&InsertionPoint
|
|
);
|
|
|
|
if (NULL == IcmpMapping) {
|
|
|
|
//
|
|
// One didn't -- create a new mappping.
|
|
//
|
|
|
|
ntStatus =
|
|
NatCreateIcmpMapping(
|
|
Interfacep,
|
|
Contextp->DestinationAddress,
|
|
Contextp->SourceAddress,
|
|
Contextp->SourceAddress,
|
|
&IcmpHeader->Identifier,
|
|
&IcmpHeader->Identifier,
|
|
NULL,
|
|
NULL,
|
|
&IcmpMapping
|
|
);
|
|
|
|
if (!NT_SUCCESS(ntStatus)) {
|
|
TRACE(
|
|
XLATE, (
|
|
"NatIcmpFirewall: error 0x%x creating mapping\n",
|
|
ntStatus
|
|
));
|
|
act = DROP;
|
|
}
|
|
} else {
|
|
KeQueryTickCount(
|
|
(PLARGE_INTEGER)&IcmpMapping->LastAccessTime
|
|
);
|
|
}
|
|
|
|
KeReleaseSpinLockFromDpcLevel( &IcmpMappingLock );
|
|
} else {
|
|
|
|
//
|
|
// Check to see if inbound for this type is permitted. If
|
|
// so, create a mapping and forward.
|
|
//
|
|
|
|
if (NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)) {
|
|
act = FORWARD;
|
|
|
|
//
|
|
// Check to see if a mapping already exists
|
|
//
|
|
|
|
PublicKey =
|
|
MAKE_ICMP_KEY(
|
|
Contextp->SourceAddress,
|
|
Contextp->DestinationAddress
|
|
);
|
|
|
|
KeAcquireSpinLockAtDpcLevel (&IcmpMappingLock);
|
|
|
|
IcmpMapping =
|
|
NatLookupInboundIcmpMapping(
|
|
PublicKey,
|
|
IcmpHeader->Identifier,
|
|
&InsertionPoint
|
|
);
|
|
|
|
if (NULL == IcmpMapping) {
|
|
|
|
//
|
|
// One didn't -- create a new mappping.
|
|
//
|
|
|
|
ntStatus =
|
|
NatCreateIcmpMapping(
|
|
Interfacep,
|
|
Contextp->SourceAddress,
|
|
Contextp->DestinationAddress,
|
|
Contextp->DestinationAddress,
|
|
&IcmpHeader->Identifier,
|
|
&IcmpHeader->Identifier,
|
|
NULL,
|
|
NULL,
|
|
&IcmpMapping
|
|
);
|
|
|
|
if (!NT_SUCCESS(ntStatus)) {
|
|
TRACE(
|
|
XLATE, (
|
|
"NatIcmpFirewall: error 0x%x creating mapping\n",
|
|
ntStatus
|
|
));
|
|
act = DROP;
|
|
}
|
|
} else {
|
|
KeQueryTickCount(
|
|
(PLARGE_INTEGER)&IcmpMapping->LastAccessTime
|
|
);
|
|
}
|
|
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
} else {
|
|
|
|
//
|
|
// Not permitted.
|
|
//
|
|
|
|
act = DROP;
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
//
|
|
// These messages are allowed inbound, but are dropped outbound
|
|
// (unless the user chooses to allow them). Allowing outbound creates
|
|
// more avenues of attack for port-scanning tools.
|
|
//
|
|
|
|
case ICMP_TIME_EXCEED:
|
|
case ICMP_PARAM_PROBLEM:
|
|
case ICMP_DEST_UNREACH:
|
|
case ICMP_SOURCE_QUENCH: {
|
|
|
|
if (NatInboundDirection == Direction) {
|
|
act = FORWARD;
|
|
} else {
|
|
act =
|
|
(NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)
|
|
? FORWARD
|
|
: DROP);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
//
|
|
// These messages are always dropped, no matter the direction
|
|
// (unless the user chooses to allow them).
|
|
//
|
|
|
|
case ICMP_REDIRECT: {
|
|
act =
|
|
(NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)
|
|
? FORWARD
|
|
: DROP);
|
|
break;
|
|
}
|
|
|
|
//
|
|
// Anything else is dropped by default.
|
|
//
|
|
|
|
default: {
|
|
act = DROP;
|
|
break;
|
|
}
|
|
}
|
|
|
|
return act;
|
|
|
|
} // NatpFirewallIcmp
|
|
|
|
|
|
|
|
|
|
VOID
|
|
NatShutdownIcmpManagement(
|
|
VOID
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine is invoked to clean up the ICMP management module
|
|
when the NAT driver is unloaded.
|
|
|
|
Arguments:
|
|
|
|
none.
|
|
|
|
Return Value:
|
|
|
|
none.
|
|
|
|
--*/
|
|
|
|
{
|
|
ExDeleteNPagedLookasideList(&IcmpLookasideList);
|
|
} // NatShutdownIcmpManagement
|
|
|
|
|
|
FORWARD_ACTION
|
|
NatTranslateIcmp(
|
|
PNAT_INTERFACE Interfacep OPTIONAL,
|
|
IP_NAT_DIRECTION Direction,
|
|
PNAT_XLATE_CONTEXT Contextp,
|
|
IPRcvBuf** InRecvBuffer,
|
|
IPRcvBuf** OutRecvBuffer
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine is invoked to perform translation on an ICMP message.
|
|
|
|
Arguments:
|
|
|
|
Interfacep - the boundary interface over which to translate, or NULL
|
|
if the packet is inbound and the receiving interface has not been
|
|
added to the NAT.
|
|
|
|
Direction - the direction in which the packet is traveling
|
|
|
|
Contextp - initialized with context-information for the packet
|
|
|
|
InRecvBuffer - input buffer-chain
|
|
|
|
OutRecvBuffer - receives modified buffer-chain.
|
|
|
|
Return Value:
|
|
|
|
FORWARD_ACTION - indicates action to take on packet.
|
|
|
|
Environment:
|
|
|
|
Invoked with a reference made to 'Interfacep' by the caller.
|
|
|
|
--*/
|
|
|
|
{
|
|
FORWARD_ACTION act;
|
|
BOOLEAN ChecksumOffloaded;
|
|
ULONG i;
|
|
PICMP_HEADER IcmpHeader;
|
|
PIP_HEADER IpHeader;
|
|
TRACE(XLATE, ("NatTranslateIcmp\n"));
|
|
|
|
//
|
|
// If the interface is in FW mode and is not a
|
|
// boundary interface, go directly to the firewall
|
|
// logic
|
|
//
|
|
|
|
if (Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& !NAT_INTERFACE_BOUNDARY(Interfacep)) {
|
|
|
|
return NatpFirewallIcmp(
|
|
Interfacep,
|
|
Direction,
|
|
Contextp
|
|
);
|
|
}
|
|
|
|
IpHeader = Contextp->Header;
|
|
IcmpHeader = (PICMP_HEADER)Contextp->ProtocolHeader;
|
|
ChecksumOffloaded = Contextp->ChecksumOffloaded;
|
|
|
|
//
|
|
// The default action is chosen as follows:
|
|
// i. if the packet is incoming on a boundary interface
|
|
// a. drop if not locally destined
|
|
// b. drop if the interface is firewalled
|
|
// c. forward otherwise
|
|
// ii. the packet is outgoing on a boundary interface, drop
|
|
// if source-address is private.
|
|
//
|
|
|
|
if (Direction == NatInboundDirection) {
|
|
if ((*Contextp->DestinationType >= DEST_REMOTE)
|
|
|| (Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& !NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type))) {
|
|
|
|
act = DROP;
|
|
} else {
|
|
act = FORWARD;
|
|
}
|
|
} else {
|
|
//
|
|
// See if the packet's source-address is private
|
|
//
|
|
// N.B. 'Interfacep' is always valid for outbound packets.
|
|
//
|
|
act = DROP;
|
|
for (i = 0; i < Interfacep->AddressCount; i++) {
|
|
if (Contextp->SourceAddress ==
|
|
Interfacep->AddressArray[i].Address
|
|
) {
|
|
//
|
|
// The packet's source-address is public,
|
|
// so we'll allow it onto the public network.
|
|
//
|
|
act = FORWARD;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
//
|
|
// See what kind of ICMP message this is,
|
|
// and translate it if possible.
|
|
//
|
|
|
|
switch (IcmpHeader->Type) {
|
|
|
|
case ICMP_ROUTER_REPLY:
|
|
case ICMP_MASK_REPLY:
|
|
case ICMP_ECHO_REPLY:
|
|
case ICMP_TIMESTAMP_REPLY: {
|
|
|
|
if (IpHeader->TimeToLive <= 1) {
|
|
TRACE(XLATE, ("NatTranslateIcmp: ttl<=1, no translation\n"));
|
|
return FORWARD;
|
|
}
|
|
if (Contextp->ProtocolRecvBuffer->ipr_size <
|
|
FIELD_OFFSET(ICMP_HEADER, EncapsulatedIpHeader) ||
|
|
!NatTranslateIcmpRequest(
|
|
Interfacep,
|
|
Direction,
|
|
Contextp,
|
|
TRUE,
|
|
ChecksumOffloaded
|
|
)) {
|
|
|
|
return act;
|
|
}
|
|
*OutRecvBuffer = *InRecvBuffer; *InRecvBuffer = NULL;
|
|
*Contextp->DestinationType = DEST_INVALID;
|
|
return FORWARD;
|
|
}
|
|
|
|
case ICMP_ROUTER_REQUEST:
|
|
case ICMP_MASK_REQUEST:
|
|
case ICMP_ECHO_REQUEST:
|
|
case ICMP_TIMESTAMP_REQUEST: {
|
|
if (IpHeader->TimeToLive <= 1) {
|
|
TRACE(XLATE, ("NatTranslateIcmp: ttl<=1, no translation\n"));
|
|
return FORWARD;
|
|
}
|
|
if (Contextp->ProtocolRecvBuffer->ipr_size <
|
|
FIELD_OFFSET(ICMP_HEADER, EncapsulatedIpHeader) ||
|
|
!NatTranslateIcmpRequest(
|
|
Interfacep,
|
|
Direction,
|
|
Contextp,
|
|
FALSE,
|
|
ChecksumOffloaded
|
|
)) {
|
|
|
|
//
|
|
// If the interface is in FW mode, we don't want to let
|
|
// a non-translated packet through, unless the user has
|
|
// configured the interface otherwise.
|
|
//
|
|
|
|
if (Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& !NAT_INTERFACE_ALLOW_ICMP(
|
|
Interfacep,
|
|
IcmpHeader->Type
|
|
)) {
|
|
|
|
act = DROP;
|
|
}
|
|
|
|
return act;
|
|
}
|
|
*OutRecvBuffer = *InRecvBuffer; *InRecvBuffer = NULL;
|
|
*Contextp->DestinationType = DEST_INVALID;
|
|
return FORWARD;
|
|
}
|
|
|
|
case ICMP_TIME_EXCEED: {
|
|
|
|
//
|
|
// Outgoing on a firewalled interface are dropped, unless
|
|
// the user has specified otherwise
|
|
//
|
|
|
|
if (Direction == NatOutboundDirection
|
|
&& Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& !NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)) {
|
|
|
|
return DROP;
|
|
}
|
|
|
|
//
|
|
// Time-exceeded messages will be triggered at each hop
|
|
// to the final destination of a traceroute sequence.
|
|
// Such messages must be translated like ICMP replies.
|
|
// Time-exceeded messages may also be generated
|
|
// in response to TCP/UDP packets, so we translate them
|
|
// in the latter case as well.
|
|
//
|
|
|
|
if (Contextp->ProtocolRecvBuffer->ipr_size <
|
|
sizeof(ICMP_HEADER) ||
|
|
(IcmpHeader->EncapsulatedIpHeader.VersionAndHeaderLength
|
|
& 0x0f) != 5) {
|
|
return act;
|
|
} else if (IcmpHeader->EncapsulatedIpHeader.Protocol ==
|
|
NAT_PROTOCOL_ICMP) {
|
|
if ((IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_ECHO_REQUEST
|
|
&& IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_MASK_REQUEST
|
|
&& IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_ROUTER_REQUEST
|
|
&& IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_TIMESTAMP_REQUEST) ||
|
|
!NatTranslateIcmpEncapsulatedRequest(
|
|
Interfacep,
|
|
Direction,
|
|
IpHeader,
|
|
IcmpHeader,
|
|
&IcmpHeader->EncapsulatedIpHeader,
|
|
&IcmpHeader->EncapsulatedIcmpHeader,
|
|
ChecksumOffloaded
|
|
)) {
|
|
return act;
|
|
}
|
|
} else if (IcmpHeader->EncapsulatedIpHeader.Protocol
|
|
== NAT_PROTOCOL_TCP ||
|
|
IcmpHeader->EncapsulatedIpHeader.Protocol
|
|
== NAT_PROTOCOL_UDP) {
|
|
if (!NatTranslateEncapsulatedRequest(
|
|
Interfacep,
|
|
Direction,
|
|
IpHeader,
|
|
IcmpHeader,
|
|
&IcmpHeader->EncapsulatedIpHeader,
|
|
&IcmpHeader->EncapsulatedUdpHeader,
|
|
ChecksumOffloaded
|
|
)) {
|
|
return act;
|
|
}
|
|
} else {
|
|
return act;
|
|
}
|
|
*OutRecvBuffer = *InRecvBuffer; *InRecvBuffer = NULL;
|
|
*Contextp->DestinationType = DEST_INVALID;
|
|
return FORWARD;
|
|
}
|
|
|
|
case ICMP_PARAM_PROBLEM:
|
|
case ICMP_DEST_UNREACH: {
|
|
|
|
//
|
|
// Outgoing on a firewalled interface are dropped, unless
|
|
// the user has specified otherwise
|
|
//
|
|
|
|
if (Direction == NatOutboundDirection
|
|
&& Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& !NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)) {
|
|
|
|
return DROP;
|
|
}
|
|
|
|
//
|
|
// Destination unreachable messages will be generated for a variety
|
|
// of reasons. We are interested in the following cases:
|
|
// * Packet-too-big: When a packet received on a boundary
|
|
// interface has the 'DF' bit set, the local forwarder may
|
|
// generate an ICMP error message to the remote endpoint
|
|
// indicating that the remote system should reduce its MSS.
|
|
// This error, however, will contain the IP address of the
|
|
// private network in the encapsulated packet, since the ICMP
|
|
// error was generated after translation.
|
|
// * Port-unreachable: Indicates that no application is listening
|
|
// at the UDP port to which a packet was sent.
|
|
//
|
|
|
|
if (Contextp->ProtocolRecvBuffer->ipr_size <
|
|
sizeof(ICMP_HEADER) ||
|
|
(IcmpHeader->EncapsulatedIpHeader.VersionAndHeaderLength
|
|
& 0x0f) != 5) {
|
|
return act;
|
|
} else if (IcmpHeader->EncapsulatedIpHeader.Protocol ==
|
|
NAT_PROTOCOL_ICMP) {
|
|
if ((IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_ECHO_REQUEST
|
|
&& IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_MASK_REQUEST
|
|
&& IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_ROUTER_REQUEST
|
|
&& IcmpHeader->EncapsulatedIcmpHeader.Type !=
|
|
ICMP_TIMESTAMP_REQUEST) ||
|
|
!NatTranslateIcmpEncapsulatedRequest(
|
|
Interfacep,
|
|
Direction,
|
|
IpHeader,
|
|
IcmpHeader,
|
|
&IcmpHeader->EncapsulatedIpHeader,
|
|
&IcmpHeader->EncapsulatedIcmpHeader,
|
|
ChecksumOffloaded
|
|
)) {
|
|
return act;
|
|
}
|
|
} else if (IcmpHeader->EncapsulatedIpHeader.Protocol
|
|
== NAT_PROTOCOL_TCP ||
|
|
IcmpHeader->EncapsulatedIpHeader.Protocol
|
|
== NAT_PROTOCOL_UDP) {
|
|
if (!NatTranslateEncapsulatedRequest(
|
|
Interfacep,
|
|
Direction,
|
|
IpHeader,
|
|
IcmpHeader,
|
|
&IcmpHeader->EncapsulatedIpHeader,
|
|
&IcmpHeader->EncapsulatedUdpHeader,
|
|
ChecksumOffloaded
|
|
)) {
|
|
return act;
|
|
}
|
|
} else {
|
|
return act;
|
|
}
|
|
|
|
*OutRecvBuffer = *InRecvBuffer; *InRecvBuffer = NULL;
|
|
*Contextp->DestinationType = DEST_INVALID;
|
|
return FORWARD;
|
|
}
|
|
|
|
case ICMP_SOURCE_QUENCH: {
|
|
|
|
//
|
|
// Outgoing on a firewalled interface are dropped, unless
|
|
// the user has specified otherwise
|
|
//
|
|
|
|
if (Direction == NatOutboundDirection
|
|
&& Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& !NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)) {
|
|
|
|
return DROP;
|
|
}
|
|
|
|
return act;
|
|
}
|
|
|
|
case ICMP_REDIRECT: {
|
|
//
|
|
// We do not translate ICMP redirect errors, since we want
|
|
// the NAT's IP forwarder to see the redirects and adjust
|
|
// its routing table accordingly.
|
|
//
|
|
// However, we do not allow inbound or outbound redirects
|
|
// across a firwall interface, unless the user has
|
|
// specified otherwise
|
|
//
|
|
|
|
if (Interfacep
|
|
&& NAT_INTERFACE_FW(Interfacep)
|
|
&& NAT_INTERFACE_ALLOW_ICMP(Interfacep, IcmpHeader->Type)) {
|
|
|
|
act = FORWARD;
|
|
}
|
|
|
|
return act;
|
|
}
|
|
|
|
default: {
|
|
break;
|
|
}
|
|
}
|
|
|
|
return act;
|
|
|
|
} // NatTranslateIcmp
|
|
|
|
|
|
BOOLEAN
|
|
NatTranslateIcmpEncapsulatedRequest(
|
|
PNAT_INTERFACE Interfacep OPTIONAL,
|
|
IP_NAT_DIRECTION Direction,
|
|
PIP_HEADER IpHeader,
|
|
PICMP_HEADER IcmpHeader,
|
|
PIP_HEADER EncapsulatedIpHeader,
|
|
struct _ENCAPSULATED_ICMP_HEADER* EncapsulatedIcmpHeader,
|
|
BOOLEAN ChecksumOffloaded
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine is invoked to translate an ICMP error message in which
|
|
we have another ICMP message encapsulated. This is necessary, for instance,
|
|
in the case of ICMP time-exceeded errors, upon which 'traceroute' relies.
|
|
|
|
Arguments:
|
|
|
|
Interfacep - the interface across which the ICMP message will be forwarded,
|
|
or NULL if the packet was received on a non-boundary interface
|
|
unknown to the NAT.
|
|
|
|
Direction - the direction in which the ICMP message is traveling
|
|
|
|
IpHeader - points to the IP header of the ICMP message
|
|
|
|
IcmpHeader - points to the ICMP header within the IP packet
|
|
|
|
EncapsulatedIpHeader - points to the IP header of the ICMP message
|
|
encapsulated in the data portion of the message
|
|
|
|
EncapsulatedIcmpHeader - points to the ICMP header of the ICMP message
|
|
encapsulated in the data portion of the message
|
|
|
|
Return Value:
|
|
|
|
BOOLEAN - TRUE if the packet was translated, FALSE otherwise
|
|
|
|
Environment:
|
|
|
|
Invoked at dispatch IRQL with a reference made to 'Interfacep'.
|
|
|
|
--*/
|
|
|
|
{
|
|
ULONG Checksum;
|
|
ULONG ChecksumDelta;
|
|
ULONG ChecksumDelta2;
|
|
PNAT_ICMP_MAPPING IcmpMapping;
|
|
ULONG64 Key;
|
|
CALLTRACE(("NatTranslateIcmpEncapsulatedRequest\n"));
|
|
|
|
//
|
|
// The checksum processing for encapsulated messages
|
|
// is extremely complicated since we must update
|
|
// (1) the ICMP checksum of the encapsulated ICMP message,
|
|
// using the change to the encapsulated ICMP identifier
|
|
// (2) the IP header-checksum of the encapsulated ICMP message
|
|
// using the change to the encapsulated IP addresses
|
|
// (3) the ICMP checksum of the containing ICMP error message
|
|
// using both the above changes as well as the changes
|
|
// to both the above checksums
|
|
// (4) the IP header-checksum of the containing ICMP error message
|
|
// using the change to the containing IP addresses
|
|
// Any changes to the logic below must be made with extreme care.
|
|
//
|
|
|
|
if (Direction == NatInboundDirection) {
|
|
Key =
|
|
MAKE_ICMP_KEY(
|
|
EncapsulatedIpHeader->DestinationAddress,
|
|
EncapsulatedIpHeader->SourceAddress
|
|
);
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
IcmpMapping =
|
|
NatLookupInboundIcmpMapping(
|
|
Key,
|
|
EncapsulatedIcmpHeader->Identifier,
|
|
NULL
|
|
);
|
|
if (!IcmpMapping) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpEncapsulatedRequest: "
|
|
"no mapping for error message\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedIcmpHeader->Identifier);
|
|
EncapsulatedIcmpHeader->Identifier = IcmpMapping->PrivateId;
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedIcmpHeader->Identifier);
|
|
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedIcmpHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedIcmpHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedIcmpHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2; CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedIpHeader->SourceAddress);
|
|
EncapsulatedIpHeader->SourceAddress =
|
|
ICMP_KEY_PRIVATE(IcmpMapping->PrivateKey);
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedIpHeader->SourceAddress);
|
|
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedIpHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2; CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IpHeader->DestinationAddress);
|
|
IpHeader->DestinationAddress =
|
|
ICMP_KEY_PRIVATE(IcmpMapping->PrivateKey);
|
|
CHECKSUM_LONG(ChecksumDelta, IpHeader->DestinationAddress);
|
|
CHECKSUM_UPDATE(IpHeader->Checksum);
|
|
KeQueryTickCount((PLARGE_INTEGER)&IcmpMapping->LastAccessTime);
|
|
} else {
|
|
Key =
|
|
MAKE_ICMP_KEY(
|
|
EncapsulatedIpHeader->SourceAddress,
|
|
EncapsulatedIpHeader->DestinationAddress
|
|
);
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
IcmpMapping =
|
|
NatLookupOutboundIcmpMapping(
|
|
Key,
|
|
EncapsulatedIcmpHeader->Identifier,
|
|
NULL
|
|
);
|
|
if (!IcmpMapping) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpEncapsulatedRequest: "
|
|
"no mapping for error message\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedIcmpHeader->Identifier);
|
|
EncapsulatedIcmpHeader->Identifier = IcmpMapping->PublicId;
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedIcmpHeader->Identifier);
|
|
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedIcmpHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedIcmpHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedIcmpHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2; CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedIpHeader->DestinationAddress);
|
|
EncapsulatedIpHeader->DestinationAddress =
|
|
ICMP_KEY_PUBLIC(IcmpMapping->PublicKey);
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedIpHeader->DestinationAddress);
|
|
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedIpHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2; CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IpHeader->SourceAddress);
|
|
IpHeader->SourceAddress =
|
|
ICMP_KEY_PUBLIC(IcmpMapping->PublicKey);
|
|
CHECKSUM_LONG(ChecksumDelta, IpHeader->SourceAddress);
|
|
CHECKSUM_UPDATE(IpHeader->Checksum);
|
|
KeQueryTickCount((PLARGE_INTEGER)&IcmpMapping->LastAccessTime);
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
|
|
//
|
|
// If checksum offloading is enabled on this packet, recompute the
|
|
// IP checksum. (There is no ICMP checksum-offload, so we will never
|
|
// need to fully recompute that.)
|
|
//
|
|
|
|
if (ChecksumOffloaded) {
|
|
NatComputeIpChecksum(IpHeader);
|
|
}
|
|
|
|
return TRUE;
|
|
} // NatTranslateIcmpEncapsulatedRequest
|
|
|
|
|
|
BOOLEAN
|
|
NatTranslateIcmpRequest(
|
|
PNAT_INTERFACE Interfacep OPTIONAL,
|
|
IP_NAT_DIRECTION Direction,
|
|
PNAT_XLATE_CONTEXT Contextp,
|
|
BOOLEAN ReplyCode,
|
|
BOOLEAN ChecksumOffloaded
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine is invoked to translate an ICMP request or reply message.
|
|
|
|
Arguments:
|
|
|
|
Interfacep - the interface across which the ICMP message is to be forwarded,
|
|
or NULL if the packet was received on a non-boundary interface unknown
|
|
to the NAT.
|
|
|
|
Direction - the direction in which the ICMP message is traveling
|
|
|
|
Contextp - contains information about the packet
|
|
|
|
ReplyCode - if TRUE, the message is a reply; otherwise, it is a request.
|
|
|
|
Return Value:
|
|
|
|
BOOLEAN - TRUE if the message was translated, FALSE otherwise.
|
|
|
|
Environment:
|
|
|
|
Invoked at dispatch IRQL with a reference made to 'Interfacep'.
|
|
|
|
--*/
|
|
|
|
{
|
|
ULONG Checksum;
|
|
ULONG ChecksumDelta;
|
|
ULONG i;
|
|
PICMP_HEADER IcmpHeader;
|
|
PNAT_ICMP_MAPPING IcmpMapping;
|
|
PIP_HEADER IpHeader;
|
|
PLIST_ENTRY InsertionPoint;
|
|
PNAT_DYNAMIC_MAPPING Mapping;
|
|
ULONG64 PrivateKey;
|
|
UCHAR Protocol;
|
|
ULONG64 PublicKey;
|
|
ULONG64 RemoteKey;
|
|
NTSTATUS status;
|
|
CALLTRACE(("NatTranslateIcmpRequest\n"));
|
|
|
|
IpHeader = Contextp->Header;
|
|
IcmpHeader = (PICMP_HEADER)Contextp->ProtocolHeader;
|
|
|
|
//
|
|
// For ICMP requests/replies we must maintain mappings, so begin by seeing
|
|
// if there is already a mapping for this particular message
|
|
//
|
|
|
|
InsertionPoint = NULL;
|
|
|
|
if (Direction == NatOutboundDirection) {
|
|
PrivateKey =
|
|
MAKE_ICMP_KEY(
|
|
Contextp->DestinationAddress,
|
|
Contextp->SourceAddress
|
|
);
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
IcmpMapping =
|
|
NatLookupOutboundIcmpMapping(
|
|
PrivateKey,
|
|
IcmpHeader->Identifier,
|
|
&InsertionPoint
|
|
);
|
|
if (!IcmpMapping) {
|
|
|
|
//
|
|
// No mapping was found, so try to create one.
|
|
//
|
|
// If the packet is an outbound reply-message,
|
|
// there really ought to be a corresponding inbound-mapping.
|
|
// Hence don't try to create one here, as it will just
|
|
// confuse the remote endpoint, which may find itself
|
|
// looking at a reply whose origin seems to be different
|
|
// from the machine to which it sent a request.
|
|
//
|
|
|
|
if (ReplyCode) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpRequest: ignoring outbound reply\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// First look for a static mapping from this private address
|
|
// to a public address. If one is found, it will be used
|
|
// in the call to 'NatCreateIcmpMapping' below. Otherwise,
|
|
// a public address will be chosen from the address-pool.
|
|
//
|
|
// N.B. When a packet is outbound, 'Interfacep' is always valid.
|
|
//
|
|
|
|
PublicKey = 0;
|
|
if (!Interfacep->NoStaticMappingExists) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
KeAcquireSpinLockAtDpcLevel(&Interfacep->Lock);
|
|
for (i = 0; i < Interfacep->AddressMappingCount; i++) {
|
|
if (Contextp->SourceAddress >
|
|
Interfacep->AddressMappingArray[i].PrivateAddress) {
|
|
continue;
|
|
} else if (Contextp->SourceAddress <
|
|
Interfacep->AddressMappingArray[i].PrivateAddress) {
|
|
break;
|
|
}
|
|
PublicKey =
|
|
Interfacep->AddressMappingArray[i].PublicAddress;
|
|
break;
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&Interfacep->Lock);
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
}
|
|
|
|
status =
|
|
NatCreateIcmpMapping(
|
|
Interfacep,
|
|
Contextp->DestinationAddress,
|
|
Contextp->SourceAddress,
|
|
(ULONG)PublicKey,
|
|
&IcmpHeader->Identifier,
|
|
NULL,
|
|
NULL,
|
|
InsertionPoint,
|
|
&IcmpMapping
|
|
);
|
|
if (!NT_SUCCESS(status)) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpRequest: error creating mapping\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Replace the Identifier in the packet,
|
|
// and replace the destination in the packet,
|
|
// updating the checksum as we go.
|
|
//
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IcmpHeader->Identifier);
|
|
IcmpHeader->Identifier = IcmpMapping->PublicId;
|
|
CHECKSUM_LONG(ChecksumDelta, IcmpHeader->Identifier);
|
|
CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IpHeader->SourceAddress);
|
|
IpHeader->SourceAddress = ICMP_KEY_PUBLIC(IcmpMapping->PublicKey);
|
|
CHECKSUM_LONG(ChecksumDelta, IpHeader->SourceAddress);
|
|
CHECKSUM_UPDATE(IpHeader->Checksum);
|
|
KeQueryTickCount((PLARGE_INTEGER)&IcmpMapping->LastAccessTime);
|
|
} else {
|
|
|
|
//
|
|
// The packet is inbound.
|
|
//
|
|
|
|
PublicKey =
|
|
MAKE_ICMP_KEY(
|
|
Contextp->SourceAddress,
|
|
Contextp->DestinationAddress
|
|
);
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
IcmpMapping =
|
|
NatLookupInboundIcmpMapping(
|
|
PublicKey,
|
|
IcmpHeader->Identifier,
|
|
&InsertionPoint
|
|
);
|
|
if (!IcmpMapping) {
|
|
|
|
//
|
|
// No mapping was found, so try to create one,
|
|
// if there is a static mapping which allows inbound sessions.
|
|
// We make an exception for inbound reply-messages;
|
|
// if the packet is a reply-message, it might be locally destined,
|
|
// in which case we pass it untouched to the stack.
|
|
//
|
|
// Don't create a mapping for an inbound reply;
|
|
// it's probably a reply to a locally-initiated request.
|
|
//
|
|
|
|
if (ReplyCode) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// First look for a static mapping from this public address
|
|
// to a private address. If one is found, it will be used
|
|
// in the call to 'NatCreateIcmpMapping' below. Otherwise,
|
|
// a public address will be chosen from the address-pool.
|
|
//
|
|
// This involves an exhaustive search since the address-mappings
|
|
// are sorted on private address rather than public address.
|
|
//
|
|
|
|
if (!Interfacep) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
return FALSE;
|
|
} else if (Interfacep->NoStaticMappingExists) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpRequest: ignoring inbound message\n"
|
|
));
|
|
return FALSE;
|
|
} else {
|
|
PrivateKey = 0;
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
KeAcquireSpinLockAtDpcLevel(&Interfacep->Lock);
|
|
for (i = 0; i < Interfacep->AddressMappingCount; i++) {
|
|
if (Interfacep->AddressMappingArray[i].PublicAddress !=
|
|
Contextp->DestinationAddress ||
|
|
!Interfacep->AddressMappingArray[i].AllowInboundSessions) {
|
|
continue;
|
|
}
|
|
PrivateKey =
|
|
Interfacep->AddressMappingArray[i].PrivateAddress;
|
|
break;
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&Interfacep->Lock);
|
|
if (!PrivateKey) {
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpRequest: ignoring inbound message\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
KeAcquireSpinLockAtDpcLevel(&IcmpMappingLock);
|
|
}
|
|
|
|
status =
|
|
NatCreateIcmpMapping(
|
|
Interfacep,
|
|
Contextp->SourceAddress,
|
|
(ULONG)PrivateKey,
|
|
Contextp->DestinationAddress,
|
|
NULL,
|
|
&IcmpHeader->Identifier,
|
|
InsertionPoint,
|
|
NULL,
|
|
&IcmpMapping
|
|
);
|
|
if (!NT_SUCCESS(status)) {
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateIcmpRequest: error creating mapping\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
}
|
|
|
|
//
|
|
// Replace the Identifier in the packet
|
|
// and replace the destination in the packet,
|
|
// updating the checksum as we go.
|
|
//
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IcmpHeader->Identifier);
|
|
IcmpHeader->Identifier = IcmpMapping->PrivateId;
|
|
CHECKSUM_LONG(ChecksumDelta, IcmpHeader->Identifier);
|
|
CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IpHeader->DestinationAddress);
|
|
IpHeader->DestinationAddress =
|
|
ICMP_KEY_PRIVATE(IcmpMapping->PrivateKey);
|
|
CHECKSUM_LONG(ChecksumDelta, IpHeader->DestinationAddress);
|
|
CHECKSUM_UPDATE(IpHeader->Checksum);
|
|
KeQueryTickCount((PLARGE_INTEGER)&IcmpMapping->LastAccessTime);
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&IcmpMappingLock);
|
|
|
|
//
|
|
// If checksum offloading is enabled on this packet, recompute the
|
|
// IP checksum. (There is no ICMP checksum-offload, so we will never
|
|
// need to fully recompute that.)
|
|
//
|
|
|
|
if (ChecksumOffloaded) {
|
|
NatComputeIpChecksum(IpHeader);
|
|
}
|
|
return TRUE;
|
|
} // NatTranslateIcmpRequest
|
|
|
|
|
|
BOOLEAN
|
|
NatTranslateEncapsulatedRequest(
|
|
PNAT_INTERFACE Interfacep OPTIONAL,
|
|
IP_NAT_DIRECTION Direction,
|
|
PIP_HEADER IpHeader,
|
|
PICMP_HEADER IcmpHeader,
|
|
PIP_HEADER EncapsulatedIpHeader,
|
|
struct _ENCAPSULATED_UDP_HEADER* EncapsulatedHeader,
|
|
BOOLEAN ChecksumOffloaded
|
|
)
|
|
|
|
/*++
|
|
|
|
Routine Description:
|
|
|
|
This routine is invoked to translate an ICMP error message in which
|
|
we have TCP segment or UDP datagram encapsulated. This is necessary,
|
|
for instance, in the case of ICMP destination-unreachable errors,
|
|
particularly where the target will take some action (such as reducing MTU)
|
|
upon receipt of the message.
|
|
|
|
Arguments:
|
|
|
|
Interfacep - the interface across which the ICMP message will be forwarded,
|
|
or NULL if the packet was received on a non-boundary interface.
|
|
|
|
Direction - the direction in which the ICMP message is traveling
|
|
|
|
IpHeader - points to the IP header of the ICMP message
|
|
|
|
IcmpHeader - points to the ICMP header within the IP packet
|
|
|
|
EncapsulatedIpHeader - points to the IP header of the TCP segment
|
|
encapsulated in the data portion of the ICMP message
|
|
|
|
EncapsulatedHeader - points to the TCP/UDP header of the TCP segment
|
|
encapsulated in the data portion of the ICMP message
|
|
|
|
Return Value:
|
|
|
|
BOOLEAN - TRUE if the packet was translated, FALSE otherwise
|
|
|
|
Environment:
|
|
|
|
Invoked at dispatch IRQL with a reference made to 'Interfacep'.
|
|
|
|
N.B.!!! This routine will acquire the mapping lock in order to search
|
|
the mapping-tree for the entry corresponding to the session for which
|
|
this ICMP error message was generated. All callers must take note,
|
|
and must ensure that the mapping lock is not already held on entry.
|
|
|
|
--*/
|
|
|
|
{
|
|
ULONG Checksum;
|
|
ULONG ChecksumDelta;
|
|
ULONG ChecksumDelta2;
|
|
ULONG64 DestinationKey;
|
|
PNAT_DYNAMIC_MAPPING Mapping;
|
|
ULONG64 ReplacementKey;
|
|
ULONG64 SourceKey;
|
|
CALLTRACE(("NatTranslateEncapsulatedRequest\n"));
|
|
|
|
//
|
|
// We begin by retrieving the mapping for the TCP session
|
|
// to which the contained segment belongs.
|
|
//
|
|
// We need to save the key with which we will replace the
|
|
// encapsulted message's contents. When an error is inbound,
|
|
// it must have been generated in response to an outbound message,
|
|
// and the outbound message contained in the error will have in it
|
|
// the public IP address and port to which we originally translated
|
|
// the outbound message. We therefore need to put back
|
|
// the private IP address and port so that the private machine
|
|
// will be able to identify the error.
|
|
// Similarly, when the error is outbound, we need to put in
|
|
// the public IP address and port so that the remote machine
|
|
// will be able to identify the error.
|
|
//
|
|
// Onward, then. Construct the key to be used for the lookup,
|
|
// take the mapping lock, and look up forward or reverse mappings.
|
|
//
|
|
|
|
MAKE_MAPPING_KEY(
|
|
DestinationKey,
|
|
EncapsulatedIpHeader->Protocol,
|
|
EncapsulatedIpHeader->SourceAddress,
|
|
EncapsulatedHeader->SourcePort
|
|
);
|
|
MAKE_MAPPING_KEY(
|
|
SourceKey,
|
|
EncapsulatedIpHeader->Protocol,
|
|
EncapsulatedIpHeader->DestinationAddress,
|
|
EncapsulatedHeader->DestinationPort
|
|
);
|
|
KeAcquireSpinLockAtDpcLevel(&MappingLock);
|
|
if (Direction == NatInboundDirection) {
|
|
Mapping = NatLookupReverseMapping(DestinationKey, SourceKey, NULL);
|
|
if (Mapping) {
|
|
ReplacementKey = Mapping->SourceKey[NatForwardPath];
|
|
} else {
|
|
Mapping = NatLookupForwardMapping(DestinationKey, SourceKey, NULL);
|
|
if (Mapping) {
|
|
ReplacementKey = Mapping->SourceKey[NatReversePath];
|
|
}
|
|
}
|
|
} else {
|
|
Mapping = NatLookupForwardMapping(DestinationKey, SourceKey, NULL);
|
|
if (Mapping) {
|
|
ReplacementKey = Mapping->DestinationKey[NatReversePath];
|
|
} else {
|
|
Mapping = NatLookupReverseMapping(DestinationKey, SourceKey, NULL);
|
|
if (Mapping) {
|
|
ReplacementKey = Mapping->DestinationKey[NatForwardPath];
|
|
}
|
|
}
|
|
}
|
|
KeReleaseSpinLockFromDpcLevel(&MappingLock);
|
|
if (!Mapping) {
|
|
TRACE(
|
|
XLATE, (
|
|
"NatTranslateEncapsulatedRequest: no mapping for message\n"
|
|
));
|
|
return FALSE;
|
|
}
|
|
|
|
//
|
|
// The checksum processing for encapsulated messages
|
|
// remains extremely complicated since we must update
|
|
// [0] for UDP messages, the UDP message checksum, using the change
|
|
// to the encapsulated UDP source port. No corresponding change
|
|
// is required for TCP segments, whose checksum appears beyond
|
|
// the eight bytes included in ICMP error messages.
|
|
// (1) the IP header-checksum of the encapsulated TCP segment
|
|
// using the change to the encapsulated IP addresses
|
|
// (2) the ICMP checksum of the containing ICMP error message
|
|
// using both the above change as well as the change
|
|
// to the above checksum
|
|
// (3) the IP header-checksum of the containing ICMP error message
|
|
// using the change to the containing IP addresses
|
|
// Any changes to the logic below must be made with extreme care.
|
|
//
|
|
|
|
if (Direction == NatInboundDirection) {
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedHeader->SourcePort);
|
|
EncapsulatedHeader->SourcePort = MAPPING_PORT(ReplacementKey);
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedHeader->SourcePort);
|
|
|
|
if (EncapsulatedIpHeader->Protocol == NAT_PROTOCOL_UDP) {
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2;
|
|
}
|
|
CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedIpHeader->SourceAddress);
|
|
EncapsulatedIpHeader->SourceAddress = MAPPING_ADDRESS(ReplacementKey);
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedIpHeader->SourceAddress);
|
|
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedIpHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2; CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IpHeader->DestinationAddress);
|
|
IpHeader->DestinationAddress = MAPPING_ADDRESS(ReplacementKey);
|
|
CHECKSUM_LONG(ChecksumDelta, IpHeader->DestinationAddress);
|
|
CHECKSUM_UPDATE(IpHeader->Checksum);
|
|
} else {
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedHeader->DestinationPort);
|
|
EncapsulatedHeader->DestinationPort = MAPPING_PORT(ReplacementKey);
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedHeader->DestinationPort);
|
|
|
|
if (EncapsulatedIpHeader->Protocol == NAT_PROTOCOL_UDP) {
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2;
|
|
}
|
|
CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~EncapsulatedIpHeader->DestinationAddress);
|
|
EncapsulatedIpHeader->DestinationAddress =
|
|
MAPPING_ADDRESS(ReplacementKey);
|
|
CHECKSUM_LONG(ChecksumDelta, EncapsulatedIpHeader->DestinationAddress);
|
|
|
|
ChecksumDelta2 = ChecksumDelta;
|
|
CHECKSUM_LONG(ChecksumDelta2, ~EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_UPDATE(EncapsulatedIpHeader->Checksum);
|
|
CHECKSUM_LONG(ChecksumDelta2, EncapsulatedIpHeader->Checksum);
|
|
ChecksumDelta = ChecksumDelta2; CHECKSUM_UPDATE(IcmpHeader->Checksum);
|
|
|
|
ChecksumDelta = 0;
|
|
CHECKSUM_LONG(ChecksumDelta, ~IpHeader->SourceAddress);
|
|
IpHeader->SourceAddress = MAPPING_ADDRESS(ReplacementKey);
|
|
CHECKSUM_LONG(ChecksumDelta, IpHeader->SourceAddress);
|
|
CHECKSUM_UPDATE(IpHeader->Checksum);
|
|
}
|
|
|
|
//
|
|
// If checksum offloading is enabled on this packet, recompute the
|
|
// IP checksum. (There is no ICMP checksum-offload, so we will never
|
|
// need to fully recompute that.)
|
|
//
|
|
|
|
if (ChecksumOffloaded) {
|
|
NatComputeIpChecksum(IpHeader);
|
|
}
|
|
|
|
return TRUE;
|
|
} // NatTranslateEncapsulatedRequest
|
|
|