NetworkPkg/Ip4Dxe/Ip4Icmp.c - third_party/edk2 - Git at Google

 /** @file

 Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent

 **/

 #include "Ip4Impl.h"

 IP4_ICMP_CLASS
 mIcmpClass[] = {
   {ICMP_ECHO_REPLY,         ICMP_QUERY_MESSAGE  },
   {1,                       ICMP_INVALID_MESSAGE},
   {2,                       ICMP_INVALID_MESSAGE},
   {ICMP_DEST_UNREACHABLE,   ICMP_ERROR_MESSAGE  },
   {ICMP_SOURCE_QUENCH,      ICMP_ERROR_MESSAGE  },
   {ICMP_REDIRECT,           ICMP_ERROR_MESSAGE  },
   {6,                       ICMP_INVALID_MESSAGE},
   {7,                       ICMP_INVALID_MESSAGE},
   {ICMP_ECHO_REQUEST,       ICMP_QUERY_MESSAGE  },
   {9,                       ICMP_INVALID_MESSAGE},
   {10,                      ICMP_INVALID_MESSAGE},
   {ICMP_TIME_EXCEEDED,      ICMP_ERROR_MESSAGE  },
   {ICMP_PARAMETER_PROBLEM,  ICMP_ERROR_MESSAGE  },
   {ICMP_TIMESTAMP ,         ICMP_QUERY_MESSAGE  },
   {14,                      ICMP_INVALID_MESSAGE},
   {ICMP_INFO_REQUEST ,      ICMP_QUERY_MESSAGE  },
   {ICMP_INFO_REPLY ,        ICMP_QUERY_MESSAGE  },
 };

 EFI_IP4_ICMP_TYPE
 mIp4SupportedIcmp[23] = {
   {ICMP_ECHO_REPLY,        ICMP_DEFAULT_CODE        },

   {ICMP_DEST_UNREACHABLE,  ICMP_NET_UNREACHABLE     },
   {ICMP_DEST_UNREACHABLE,  ICMP_HOST_UNREACHABLE    },
   {ICMP_DEST_UNREACHABLE,  ICMP_PROTO_UNREACHABLE   },
   {ICMP_DEST_UNREACHABLE,  ICMP_PORT_UNREACHABLE    },
   {ICMP_DEST_UNREACHABLE,  ICMP_FRAGMENT_FAILED     },
   {ICMP_DEST_UNREACHABLE,  ICMP_SOURCEROUTE_FAILED  },
   {ICMP_DEST_UNREACHABLE,  ICMP_NET_UNKNOWN         },
   {ICMP_DEST_UNREACHABLE,  ICMP_HOST_UNKNOWN        },
   {ICMP_DEST_UNREACHABLE,  ICMP_SOURCE_ISOLATED     },
   {ICMP_DEST_UNREACHABLE,  ICMP_NET_PROHIBITED      },
   {ICMP_DEST_UNREACHABLE,  ICMP_HOST_PROHIBITED     },
   {ICMP_DEST_UNREACHABLE,  ICMP_NET_UNREACHABLE_TOS },
   {ICMP_DEST_UNREACHABLE,  ICMP_HOST_UNREACHABLE_TOS},

   {ICMP_SOURCE_QUENCH,     ICMP_DEFAULT_CODE        },

   {ICMP_REDIRECT,          ICMP_NET_REDIRECT        },
   {ICMP_REDIRECT,          ICMP_HOST_REDIRECT       },
   {ICMP_REDIRECT,          ICMP_NET_TOS_REDIRECT    },
   {ICMP_REDIRECT,          ICMP_HOST_TOS_REDIRECT   },

   {ICMP_ECHO_REQUEST,      ICMP_DEFAULT_CODE        },

   {ICMP_TIME_EXCEEDED,     ICMP_TIMEOUT_IN_TRANSIT  },
   {ICMP_TIME_EXCEEDED,     ICMP_TIMEOUT_REASSEMBLE  },

   {ICMP_PARAMETER_PROBLEM, ICMP_DEFAULT_CODE        },
 };


 /**
   Process the ICMP redirect. Find the instance then update
   its route cache.

   All kinds of redirect is treated as host redirect as
   specified by RFC1122 3.3.1.2:
   "Since the subnet mask appropriate to the destination
   address is generally not known, a Network Redirect
   message SHOULD be treated identically to a Host Redirect
   message;"

   @param[in]  IpSb               The IP4 service binding instance that received
                                  the packet.
   @param[in]  Head               The IP head of the received ICMPpacket.
   @param[in]  Packet             The content of the ICMP redirect packet with IP
                                  head removed.
   @param[in]  Icmp               The buffer to store the ICMP error message if
                                  something is wrong.

   @retval EFI_INVALID_PARAMETER  The parameter is invalid
   @retval EFI_SUCCESS            Successfully updated the route caches

 **/
 EFI_STATUS
 Ip4ProcessIcmpRedirect (
   IN IP4_SERVICE            *IpSb,
   IN IP4_HEAD               *Head,
   IN NET_BUF                *Packet,
   IN IP4_ICMP_ERROR_HEAD    *Icmp
   )
 {
   LIST_ENTRY                *Entry;
   IP4_PROTOCOL              *Ip4Instance;
   IP4_ROUTE_CACHE_ENTRY     *CacheEntry;
   IP4_INTERFACE             *IpIf;
   IP4_ADDR                  Gateway;
   IP4_ADDR                  Src;
   IP4_ADDR                  Dst;

   //
   // Find the interface whose IP address is the source of the
   // orgianl IP packet.
   //
   IpIf    = Ip4FindInterface (IpSb, NTOHL (Icmp->IpHead.Src));
   Gateway = NTOHL (Icmp->Fourth);

   //
   // discard the packet if the new gateway address it specifies
   // is not on the same connected net through which the Redirect
   // arrived. (RFC1122 3.2.2.2).
   //
   if ((IpIf == NULL) || !IP4_NET_EQUAL (Gateway, IpIf->Ip, IpIf->SubnetMask)) {
     NetbufFree (Packet);
     return EFI_INVALID_PARAMETER;
   }

   //
   // Update each IP child's route cache on the interface.
   //
   NET_LIST_FOR_EACH (Entry, &IpIf->IpInstances) {
     Ip4Instance = NET_LIST_USER_STRUCT (Entry, IP4_PROTOCOL, AddrLink);

     if (Ip4Instance->RouteTable == NULL) {
       continue;
     }

     Dst = NTOHL (Icmp->IpHead.Dst);
     Src = NTOHL (Icmp->IpHead.Src);
     CacheEntry = Ip4FindRouteCache (Ip4Instance->RouteTable, Dst, Src);

     //
     // Only update the route cache's gateway if the source of the
     // Redirect is the current first-hop gateway
     //
     if ((CacheEntry != NULL) && (NTOHL (Head->Src) == CacheEntry->NextHop)) {
       CacheEntry->NextHop = Gateway;
     }
   }

   NetbufFree (Packet);
   return EFI_SUCCESS;
 }


 /**
   Process the ICMP error packet. If it is an ICMP redirect packet,
   update call Ip4ProcessIcmpRedirect to update the IP instance's
   route cache, otherwise, deliver the packet to upper layer.

   @param[in]  IpSb               The IP4 service that received the packet.
   @param[in]  Head               The IP4 head of the ICMP error packet
   @param[in]  Packet             The content of the ICMP error with IP4 head
                                  removed.

   @retval EFI_SUCCESS            The ICMP error is processed successfully.
   @retval EFI_INVALID_PARAMETER  The packet is invalid
   @retval Others                 Failed to process the packet.

 **/
 EFI_STATUS
 Ip4ProcessIcmpError (
   IN IP4_SERVICE            *IpSb,
   IN IP4_HEAD               *Head,
   IN NET_BUF                *Packet
   )
 {
   IP4_ICMP_ERROR_HEAD       Icmp;

   if (Packet->TotalSize < sizeof (Icmp)) {
     NetbufFree (Packet);
     return EFI_INVALID_PARAMETER;
   }

   NetbufCopy (Packet, 0, sizeof (Icmp), (UINT8 *) &Icmp);

   //
   // If it is an ICMP redirect error, update the route cache
   // as RFC1122. Otherwise, demultiplex it to IP instances.
   //
   if (Icmp.Head.Type == ICMP_REDIRECT) {
     return Ip4ProcessIcmpRedirect (IpSb, Head, Packet, &Icmp);
   }

   IP4_GET_CLIP_INFO (Packet)->Status = EFI_ICMP_ERROR;
   return Ip4Demultiplex (IpSb, Head, Packet, NULL, 0);
 }


 /**
   Replay an ICMP echo request.

   @param[in]  IpSb               The IP4 service that receivd the packet
   @param[in]  Head               The IP4 head of the ICMP error packet
   @param[in]  Packet             The content of the ICMP error with IP4 head
                                  removed.

   @retval EFI_OUT_OF_RESOURCES   Failed to allocate resource.
   @retval EFI_SUCCESS            The ICMP Echo request is successfully answered.
   @retval Others                 Failed to answer the ICMP echo request.

 **/
 EFI_STATUS
 Ip4IcmpReplyEcho (
   IN IP4_SERVICE            *IpSb,
   IN IP4_HEAD               *Head,
   IN NET_BUF                *Packet
   )
 {
   IP4_ICMP_QUERY_HEAD       *Icmp;
   NET_BUF                   *Data;
   EFI_STATUS                Status;
   IP4_HEAD                  ReplyHead;

   //
   // make a copy the packet, it is really a bad idea to
   // send the MNP's buffer back to MNP.
   //
   Data = NetbufDuplicate (Packet, NULL, IP4_MAX_HEADLEN);

   if (Data == NULL) {
     Status = EFI_OUT_OF_RESOURCES;
     goto ON_EXIT;
   }

   //
   // Change the ICMP type to echo reply, exchange the source
   // and destination, then send it. The source is updated to
   // use specific destination. See RFC1122. SRR/RR option
   // update is omitted.
   //
   Icmp                = (IP4_ICMP_QUERY_HEAD *) NetbufGetByte (Data, 0, NULL);
   ASSERT (Icmp != NULL);
   Icmp->Head.Type     = ICMP_ECHO_REPLY;
   Icmp->Head.Checksum = 0;
   Icmp->Head.Checksum = (UINT16) (~NetblockChecksum ((UINT8 *) Icmp, Data->TotalSize));

   ReplyHead.Tos       = 0;
   ReplyHead.Fragment  = 0;
   ReplyHead.Ttl       = 64;
   ReplyHead.Protocol  = EFI_IP_PROTO_ICMP;
   ReplyHead.Src       = 0;

   //
   // Ip4Output will select a source for us
   //
   ReplyHead.Dst = Head->Src;

   Status = Ip4Output (
              IpSb,
              NULL,
              Data,
              &ReplyHead,
              NULL,
              0,
              IP4_ALLZERO_ADDRESS,
              Ip4SysPacketSent,
              NULL
              );
   if (EFI_ERROR (Status)) {
     NetbufFree (Data);
   }

 ON_EXIT:
   NetbufFree (Packet);
   return Status;
 }


 /**
   Process the ICMP query message. If it is an ICMP echo
   request, answer it. Otherwise deliver it to upper layer.

   @param[in]  IpSb               The IP4 service that receivd the packet
   @param[in]  Head               The IP4 head of the ICMP query packet
   @param[in]  Packet             The content of the ICMP query with IP4 head
                                  removed.

   @retval EFI_INVALID_PARAMETER  The packet is invalid
   @retval EFI_SUCCESS            The ICMP query message is processed
   @retval Others                 Failed to process ICMP query.

 **/
 EFI_STATUS
 Ip4ProcessIcmpQuery (
   IN IP4_SERVICE            *IpSb,
   IN IP4_HEAD               *Head,
   IN NET_BUF                *Packet
   )
 {
   IP4_ICMP_QUERY_HEAD       Icmp;

   if (Packet->TotalSize < sizeof (Icmp)) {
     NetbufFree (Packet);
     return EFI_INVALID_PARAMETER;
   }

   NetbufCopy (Packet, 0, sizeof (Icmp), (UINT8 *) &Icmp);

   if (Icmp.Head.Type == ICMP_ECHO_REQUEST) {
     return Ip4IcmpReplyEcho (IpSb, Head, Packet);
   }

   return Ip4Demultiplex (IpSb, Head, Packet, NULL, 0);
 }


 /**
   Handle the ICMP packet. First validate the message format,
   then according to the message types, process it as query or
   error packet.

   @param[in]  IpSb               The IP4 service that receivd the packet.
   @param[in]  Head               The IP4 head of the ICMP query packet.
   @param[in]  Packet             The content of the ICMP query with IP4 head
                                  removed.

   @retval EFI_INVALID_PARAMETER  The packet is malformatted.
   @retval EFI_SUCCESS            The ICMP message is successfully processed.
   @retval Others                 Failed to handle ICMP packet.

 **/
 EFI_STATUS
 Ip4IcmpHandle (
   IN IP4_SERVICE            *IpSb,
   IN IP4_HEAD               *Head,
   IN NET_BUF                *Packet
   )
 {
   IP4_ICMP_HEAD             Icmp;
   UINT16                    Checksum;

   if (Packet->TotalSize < sizeof (Icmp)) {
     goto DROP;
   }

   NetbufCopy (Packet, 0, sizeof (Icmp), (UINT8 *) &Icmp);

   if (Icmp.Type > ICMP_TYPE_MAX) {
     goto DROP;
   }

   Checksum = (UINT16) (~NetbufChecksum (Packet));
   if ((Icmp.Checksum != 0) && (Checksum != 0)) {
     goto DROP;
   }

   if (mIcmpClass[Icmp.Type].IcmpClass == ICMP_ERROR_MESSAGE) {
     return Ip4ProcessIcmpError (IpSb, Head, Packet);

   } else if (mIcmpClass[Icmp.Type].IcmpClass == ICMP_QUERY_MESSAGE) {
     return Ip4ProcessIcmpQuery (IpSb, Head, Packet);

   }

 DROP:
   NetbufFree (Packet);
   return EFI_INVALID_PARAMETER;
 }
	/** @file

	Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
	SPDX-License-Identifier: BSD-2-Clause-Patent

	**/

	#include "Ip4Impl.h"

	IP4_ICMP_CLASS
	mIcmpClass[] = {
	{ICMP_ECHO_REPLY, ICMP_QUERY_MESSAGE },
	{1, ICMP_INVALID_MESSAGE},
	{2, ICMP_INVALID_MESSAGE},
	{ICMP_DEST_UNREACHABLE, ICMP_ERROR_MESSAGE },
	{ICMP_SOURCE_QUENCH, ICMP_ERROR_MESSAGE },
	{ICMP_REDIRECT, ICMP_ERROR_MESSAGE },
	{6, ICMP_INVALID_MESSAGE},
	{7, ICMP_INVALID_MESSAGE},
	{ICMP_ECHO_REQUEST, ICMP_QUERY_MESSAGE },
	{9, ICMP_INVALID_MESSAGE},
	{10, ICMP_INVALID_MESSAGE},
	{ICMP_TIME_EXCEEDED, ICMP_ERROR_MESSAGE },
	{ICMP_PARAMETER_PROBLEM, ICMP_ERROR_MESSAGE },
	{ICMP_TIMESTAMP , ICMP_QUERY_MESSAGE },
	{14, ICMP_INVALID_MESSAGE},
	{ICMP_INFO_REQUEST , ICMP_QUERY_MESSAGE },
	{ICMP_INFO_REPLY , ICMP_QUERY_MESSAGE },
	};

	EFI_IP4_ICMP_TYPE
	mIp4SupportedIcmp[23] = {
	{ICMP_ECHO_REPLY, ICMP_DEFAULT_CODE },

	{ICMP_DEST_UNREACHABLE, ICMP_NET_UNREACHABLE },
	{ICMP_DEST_UNREACHABLE, ICMP_HOST_UNREACHABLE },
	{ICMP_DEST_UNREACHABLE, ICMP_PROTO_UNREACHABLE },
	{ICMP_DEST_UNREACHABLE, ICMP_PORT_UNREACHABLE },
	{ICMP_DEST_UNREACHABLE, ICMP_FRAGMENT_FAILED },
	{ICMP_DEST_UNREACHABLE, ICMP_SOURCEROUTE_FAILED },
	{ICMP_DEST_UNREACHABLE, ICMP_NET_UNKNOWN },
	{ICMP_DEST_UNREACHABLE, ICMP_HOST_UNKNOWN },
	{ICMP_DEST_UNREACHABLE, ICMP_SOURCE_ISOLATED },
	{ICMP_DEST_UNREACHABLE, ICMP_NET_PROHIBITED },
	{ICMP_DEST_UNREACHABLE, ICMP_HOST_PROHIBITED },
	{ICMP_DEST_UNREACHABLE, ICMP_NET_UNREACHABLE_TOS },
	{ICMP_DEST_UNREACHABLE, ICMP_HOST_UNREACHABLE_TOS},

	{ICMP_SOURCE_QUENCH, ICMP_DEFAULT_CODE },

	{ICMP_REDIRECT, ICMP_NET_REDIRECT },
	{ICMP_REDIRECT, ICMP_HOST_REDIRECT },
	{ICMP_REDIRECT, ICMP_NET_TOS_REDIRECT },
	{ICMP_REDIRECT, ICMP_HOST_TOS_REDIRECT },

	{ICMP_ECHO_REQUEST, ICMP_DEFAULT_CODE },

	{ICMP_TIME_EXCEEDED, ICMP_TIMEOUT_IN_TRANSIT },
	{ICMP_TIME_EXCEEDED, ICMP_TIMEOUT_REASSEMBLE },

	{ICMP_PARAMETER_PROBLEM, ICMP_DEFAULT_CODE },
	};



	/**
	Process the ICMP redirect. Find the instance then update
	its route cache.

	All kinds of redirect is treated as host redirect as
	specified by RFC1122 3.3.1.2:
	"Since the subnet mask appropriate to the destination
	address is generally not known, a Network Redirect
	message SHOULD be treated identically to a Host Redirect
	message;"

	@param[in] IpSb The IP4 service binding instance that received
	the packet.
	@param[in] Head The IP head of the received ICMPpacket.
	@param[in] Packet The content of the ICMP redirect packet with IP
	head removed.
	@param[in] Icmp The buffer to store the ICMP error message if
	something is wrong.

	@retval EFI_INVALID_PARAMETER The parameter is invalid
	@retval EFI_SUCCESS Successfully updated the route caches

	**/
	EFI_STATUS
	Ip4ProcessIcmpRedirect (
	IN IP4_SERVICE *IpSb,
	IN IP4_HEAD *Head,
	IN NET_BUF *Packet,
	IN IP4_ICMP_ERROR_HEAD *Icmp
	)
	{
	LIST_ENTRY *Entry;
	IP4_PROTOCOL *Ip4Instance;
	IP4_ROUTE_CACHE_ENTRY *CacheEntry;
	IP4_INTERFACE *IpIf;
	IP4_ADDR Gateway;
	IP4_ADDR Src;
	IP4_ADDR Dst;

	//
	// Find the interface whose IP address is the source of the
	// orgianl IP packet.
	//
	IpIf = Ip4FindInterface (IpSb, NTOHL (Icmp->IpHead.Src));
	Gateway = NTOHL (Icmp->Fourth);

	//
	// discard the packet if the new gateway address it specifies
	// is not on the same connected net through which the Redirect
	// arrived. (RFC1122 3.2.2.2).
	//
	if ((IpIf == NULL) \|\| !IP4_NET_EQUAL (Gateway, IpIf->Ip, IpIf->SubnetMask)) {
	NetbufFree (Packet);
	return EFI_INVALID_PARAMETER;
	}

	//
	// Update each IP child's route cache on the interface.
	//
	NET_LIST_FOR_EACH (Entry, &IpIf->IpInstances) {
	Ip4Instance = NET_LIST_USER_STRUCT (Entry, IP4_PROTOCOL, AddrLink);

	if (Ip4Instance->RouteTable == NULL) {
	continue;
	}

	Dst = NTOHL (Icmp->IpHead.Dst);
	Src = NTOHL (Icmp->IpHead.Src);
	CacheEntry = Ip4FindRouteCache (Ip4Instance->RouteTable, Dst, Src);

	//
	// Only update the route cache's gateway if the source of the
	// Redirect is the current first-hop gateway
	//
	if ((CacheEntry != NULL) && (NTOHL (Head->Src) == CacheEntry->NextHop)) {
	CacheEntry->NextHop = Gateway;
	}
	}

	NetbufFree (Packet);
	return EFI_SUCCESS;
	}


	/**
	Process the ICMP error packet. If it is an ICMP redirect packet,
	update call Ip4ProcessIcmpRedirect to update the IP instance's
	route cache, otherwise, deliver the packet to upper layer.

	@param[in] IpSb The IP4 service that received the packet.
	@param[in] Head The IP4 head of the ICMP error packet
	@param[in] Packet The content of the ICMP error with IP4 head
	removed.

	@retval EFI_SUCCESS The ICMP error is processed successfully.
	@retval EFI_INVALID_PARAMETER The packet is invalid
	@retval Others Failed to process the packet.

	**/
	EFI_STATUS
	Ip4ProcessIcmpError (
	IN IP4_SERVICE *IpSb,
	IN IP4_HEAD *Head,
	IN NET_BUF *Packet
	)
	{
	IP4_ICMP_ERROR_HEAD Icmp;

	if (Packet->TotalSize < sizeof (Icmp)) {
	NetbufFree (Packet);
	return EFI_INVALID_PARAMETER;
	}

	NetbufCopy (Packet, 0, sizeof (Icmp), (UINT8 *) &Icmp);

	//
	// If it is an ICMP redirect error, update the route cache
	// as RFC1122. Otherwise, demultiplex it to IP instances.
	//
	if (Icmp.Head.Type == ICMP_REDIRECT) {
	return Ip4ProcessIcmpRedirect (IpSb, Head, Packet, &Icmp);
	}

	IP4_GET_CLIP_INFO (Packet)->Status = EFI_ICMP_ERROR;
	return Ip4Demultiplex (IpSb, Head, Packet, NULL, 0);
	}


	/**
	Replay an ICMP echo request.

	@param[in] IpSb The IP4 service that receivd the packet
	@param[in] Head The IP4 head of the ICMP error packet
	@param[in] Packet The content of the ICMP error with IP4 head
	removed.

	@retval EFI_OUT_OF_RESOURCES Failed to allocate resource.
	@retval EFI_SUCCESS The ICMP Echo request is successfully answered.
	@retval Others Failed to answer the ICMP echo request.

	**/
	EFI_STATUS
	Ip4IcmpReplyEcho (
	IN IP4_SERVICE *IpSb,
	IN IP4_HEAD *Head,
	IN NET_BUF *Packet
	)
	{
	IP4_ICMP_QUERY_HEAD *Icmp;
	NET_BUF *Data;
	EFI_STATUS Status;
	IP4_HEAD ReplyHead;

	//
	// make a copy the packet, it is really a bad idea to
	// send the MNP's buffer back to MNP.
	//
	Data = NetbufDuplicate (Packet, NULL, IP4_MAX_HEADLEN);

	if (Data == NULL) {
	Status = EFI_OUT_OF_RESOURCES;
	goto ON_EXIT;
	}

	//
	// Change the ICMP type to echo reply, exchange the source
	// and destination, then send it. The source is updated to
	// use specific destination. See RFC1122. SRR/RR option
	// update is omitted.
	//
	Icmp = (IP4_ICMP_QUERY_HEAD *) NetbufGetByte (Data, 0, NULL);
	ASSERT (Icmp != NULL);
	Icmp->Head.Type = ICMP_ECHO_REPLY;
	Icmp->Head.Checksum = 0;
	Icmp->Head.Checksum = (UINT16) (~NetblockChecksum ((UINT8 *) Icmp, Data->TotalSize));

	ReplyHead.Tos = 0;
	ReplyHead.Fragment = 0;
	ReplyHead.Ttl = 64;
	ReplyHead.Protocol = EFI_IP_PROTO_ICMP;
	ReplyHead.Src = 0;

	//
	// Ip4Output will select a source for us
	//
	ReplyHead.Dst = Head->Src;

	Status = Ip4Output (
	IpSb,
	NULL,
	Data,
	&ReplyHead,
	NULL,
	0,
	IP4_ALLZERO_ADDRESS,
	Ip4SysPacketSent,
	NULL
	);
	if (EFI_ERROR (Status)) {
	NetbufFree (Data);
	}

	ON_EXIT:
	NetbufFree (Packet);
	return Status;
	}


	/**
	Process the ICMP query message. If it is an ICMP echo
	request, answer it. Otherwise deliver it to upper layer.

	@param[in] IpSb The IP4 service that receivd the packet
	@param[in] Head The IP4 head of the ICMP query packet
	@param[in] Packet The content of the ICMP query with IP4 head
	removed.

	@retval EFI_INVALID_PARAMETER The packet is invalid
	@retval EFI_SUCCESS The ICMP query message is processed
	@retval Others Failed to process ICMP query.

	**/
	EFI_STATUS
	Ip4ProcessIcmpQuery (
	IN IP4_SERVICE *IpSb,
	IN IP4_HEAD *Head,
	IN NET_BUF *Packet
	)
	{
	IP4_ICMP_QUERY_HEAD Icmp;

	if (Packet->TotalSize < sizeof (Icmp)) {
	NetbufFree (Packet);
	return EFI_INVALID_PARAMETER;
	}

	NetbufCopy (Packet, 0, sizeof (Icmp), (UINT8 *) &Icmp);

	if (Icmp.Head.Type == ICMP_ECHO_REQUEST) {
	return Ip4IcmpReplyEcho (IpSb, Head, Packet);
	}

	return Ip4Demultiplex (IpSb, Head, Packet, NULL, 0);
	}


	/**
	Handle the ICMP packet. First validate the message format,
	then according to the message types, process it as query or
	error packet.

	@param[in] IpSb The IP4 service that receivd the packet.
	@param[in] Head The IP4 head of the ICMP query packet.
	@param[in] Packet The content of the ICMP query with IP4 head
	removed.

	@retval EFI_INVALID_PARAMETER The packet is malformatted.
	@retval EFI_SUCCESS The ICMP message is successfully processed.
	@retval Others Failed to handle ICMP packet.

	**/
	EFI_STATUS
	Ip4IcmpHandle (
	IN IP4_SERVICE *IpSb,
	IN IP4_HEAD *Head,
	IN NET_BUF *Packet
	)
	{
	IP4_ICMP_HEAD Icmp;
	UINT16 Checksum;

	if (Packet->TotalSize < sizeof (Icmp)) {
	goto DROP;
	}

	NetbufCopy (Packet, 0, sizeof (Icmp), (UINT8 *) &Icmp);

	if (Icmp.Type > ICMP_TYPE_MAX) {
	goto DROP;
	}

	Checksum = (UINT16) (~NetbufChecksum (Packet));
	if ((Icmp.Checksum != 0) && (Checksum != 0)) {
	goto DROP;
	}

	if (mIcmpClass[Icmp.Type].IcmpClass == ICMP_ERROR_MESSAGE) {
	return Ip4ProcessIcmpError (IpSb, Head, Packet);

	} else if (mIcmpClass[Icmp.Type].IcmpClass == ICMP_QUERY_MESSAGE) {
	return Ip4ProcessIcmpQuery (IpSb, Head, Packet);

	}

	DROP:
	NetbufFree (Packet);
	return EFI_INVALID_PARAMETER;
	}