ipv4.cpp revision 7f9e7d10ed0201f80200e1334b126abb1e60a1b0
/* $Id$ */
/** @file
* IPRT - IPv4 Checksum calculation and validation.
*/
/*
* Copyright (C) 2008 Sun Microsystems, Inc.
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
/**
* Calculates the checksum of the IPv4 header.
*
* @returns Checksum.
* @param pIpHdr Pointer to the IPv4 header to checksum, network endian (big).
* Assumes the caller already checked the minimum size requirement.
*/
{
/*+ paw[5] == 0 */ /* ip_sum */
/* any options */
{
/* this is a bit insane... (identical to the TCP header) */
{
case 9: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17]; break;
case 10: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19]; break;
case 11: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21]; break;
case 12: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23]; break;
case 13: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25]; break;
case 14: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27]; break;
case 15: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27] + paw[28] + paw[29]; break;
default:
AssertFailed();
}
}
/* 16-bit one complement fun */
}
/**
* Verifies the header version, header size, packet size, and header checksum
* of the specified IPv4 header.
*
* @returns true if valid, false if invalid.
* @param pIpHdr Pointer to the IPv4 header to validate. Network endian (big).
* @param cbHdrMax The max header size, or the max size of what pIpHdr points
* to if you like. Note that an IPv4 header can be up to 60 bytes.
* @param cbPktMax The max IP packet size, IP header and payload. This doesn't have
* to be mapped following pIpHdr.
*/
{
return false;
return false;
{
Assert(pIpHdr->ip_hl * 4 > cbPktMax); /* You'll hit this if you mapped/copy too little of the header! */
return false;
}
return false;
return false;
return false;
return true;
}
/**
* Calculates the checksum of a pseudo header given an IPv4 header [inlined].
*
* @returns 32-bit intermediary checksum value.
* @param pIpHdr The IP header (network endian (big)).
*/
{
#ifdef RT_BIG_ENDIAN
#else
#endif
+ RT_H2BE_U16(cbPayload);
return iSum;
}
/**
* Calculates the checksum of a pseudo header given an IPv4 header.
*
* @returns 32-bit intermediary checksum value.
* @param pIpHdr The IP header (network endian (big)).
*/
{
return rtNetIPv4PseudoChecksum(pIpHdr);
}
/**
* Calculates the checksum of a pseudo header given the individual components.
*
* @returns 32-bit intermediary checksum value.
* @param SrcAddr The source address in host endian.
* @param DstAddr The destination address in host endian.
* @param bProtocol The protocol number.
* @param cbPkt The packet size (host endian of course) (no IPv4 header).
*/
RTDECL(uint32_t) RTNetIPv4PseudoChecksumBits(RTNETADDRIPV4 SrcAddr, RTNETADDRIPV4 DstAddr, uint8_t bProtocol, uint16_t cbPkt)
{
#ifdef RT_BIG_ENDIAN
#else
#endif
+ RT_H2BE_U16(cbPkt);
return iSum;
}
/**
* Adds the checksum of the UDP header to the intermediate checksum value [inlined].
*
* @returns 32-bit intermediary checksum value.
* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
* @param iSum The 32-bit intermediate checksum value.
*/
{
/*+ pUdpHdr->uh_sum = 0 */
return iSum;
}
/**
* Adds the checksum of the UDP header to the intermediate checksum value.
*
* @returns 32-bit intermediary checksum value.
* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
* @param iSum The 32-bit intermediate checksum value.
*/
{
}
/**
* Adds the checksum of the TCP header to the intermediate checksum value [inlined].
*
* @returns 32-bit intermediary checksum value.
* @param pUdpHdr Pointer to the TCP header to checksum, network endian (big).
* Assums the caller has already validate it and made sure the
* entire header is present.
* @param iSum The 32-bit intermediate checksum value.
*/
{
/*+ paw[8] == 0 */ /* th_sum */
{
/* this is a bit insane... (identical to the IPv4 header) */
{
case 9: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17]; break;
case 10: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19]; break;
case 11: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21]; break;
case 12: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23]; break;
case 13: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25]; break;
case 14: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27]; break;
case 15: iSum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19] + paw[20] + paw[21] + paw[22] + paw[23] + paw[24] + paw[25] + paw[26] + paw[27] + paw[28] + paw[29]; break;
default:
AssertFailed();
}
}
return iSum;
}
/**
* Adds the checksum of the TCP header to the intermediate checksum value.
*
* @returns 32-bit intermediary checksum value.
* @param pUdpHdr Pointer to the TCP header to checksum, network endian (big).
* Assums the caller has already validate it and made sure the
* entire header is present.
* @param iSum The 32-bit intermediate checksum value.
*/
{
}
/**
* Adds the checksum of the specified data segment to the intermediate checksum value [inlined].
*
* @returns 32-bit intermediary checksum value.
* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
* @param iSum The 32-bit intermediate checksum value.
* @param pfOdd This is used to keep track of odd bits, initialize to false
* when starting to checksum the data (aka text) after a TCP
* or UDP header (data never start at an odd offset).
*/
DECLINLINE(uint32_t) rtNetIPv4AddDataChecksum(void const *pvData, size_t cbData, uint32_t iSum, bool *pfOdd)
{
if (*pfOdd)
{
#ifdef RT_BIG_ENDIAN
/* there was an odd byte in the previous chunk, add the lower byte. */
#else
/* there was an odd byte in the previous chunk, add the upper byte. */
#endif
/* skip the byte. */
cbData--;
if (!cbData)
return iSum;
}
/* iterate the data. */
while (cbData > 1)
{
pw++;
cbData -= 2;
}
/* handle odd byte. */
if (cbData)
{
#ifdef RT_BIG_ENDIAN
#else
#endif
*pfOdd = true;
}
else
*pfOdd = false;
return iSum;
}
/**
* Adds the checksum of the specified data segment to the intermediate checksum value.
*
* @returns 32-bit intermediary checksum value.
* @param pUdpHdr Pointer to the UDP header to checksum, network endian (big).
* @param iSum The 32-bit intermediate checksum value.
* @param pfOdd This is used to keep track of odd bits, initialize to false
* when starting to checksum the data (aka text) after a TCP
* or UDP header (data never start at an odd offset).
*/
RTDECL(uint32_t) RTNetIPv4AddDataChecksum(void const *pvData, size_t cbData, uint32_t iSum, bool *pfOdd)
{
}
/**
* Finalizes a IPv4 checksum [inlined].
*
* @returns The checksum.
* @param iSum The 32-bit intermediate checksum value.
*/
{
/* 16-bit one complement fun */
}
/**
* Finalizes a IPv4 checksum.
*
* @returns The checksum.
* @param iSum The 32-bit intermediate checksum value.
*/
{
return rtNetIPv4FinalizeChecksum(iSum);
}
/**
* Calculates the checksum for the UDP header given the IP header,
* UDP header and payload.
*
* @returns The checksum.
* @param pIpHdr Pointer to the IPv4 header, in network endian (big).
* @param pUdpHdr Pointer to the UDP header, in network endian (big).
* @param pvData Pointer to the UDP payload. The size is taken from the
* UDP header and the caller is supposed to have validated
* this before calling.
*/
{
bool fOdd = false;
iSum = RTNetIPv4AddDataChecksum(pvData, RT_BE2H_U16(pUdpHdr->uh_ulen) - sizeof(*pUdpHdr), iSum, &fOdd);
return iSum;
}