diff options
Diffstat (limited to 'src/VBox/Runtime/common/checksum/ipv4.cpp')
| -rw-r--r-- | src/VBox/Runtime/common/checksum/ipv4.cpp | 774 |
1 files changed, 774 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/checksum/ipv4.cpp b/src/VBox/Runtime/common/checksum/ipv4.cpp new file mode 100644 index 00000000..2d75b989 --- /dev/null +++ b/src/VBox/Runtime/common/checksum/ipv4.cpp @@ -0,0 +1,774 @@ +/* $Id: ipv4.cpp $ */ +/** @file + * IPRT - IPv4 Checksum calculation and validation. + */ + +/* + * Copyright (C) 2008-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included + * in the VirtualBox 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. + * + * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 + */ + + +/********************************************************************************************************************************* +* Header Files * +*********************************************************************************************************************************/ +#include <iprt/net.h> +#include "internal/iprt.h" + +#include <iprt/asm.h> +#include <iprt/assert.h> + + +/** + * Calculates the checksum of the IPv4 header. + * + * @returns Checksum (network endian). + * @param pIpHdr Pointer to the IPv4 header to checksum, network endian (big). + * Assumes the caller already checked the minimum size requirement. + */ +RTDECL(uint16_t) RTNetIPv4HdrChecksum(PCRTNETIPV4 pIpHdr) +{ + uint16_t const *paw = (uint16_t const *)pIpHdr; + uint32_t u32Sum = paw[0] /* ip_hl */ + + paw[1] /* ip_len */ + + paw[2] /* ip_id */ + + paw[3] /* ip_off */ + + paw[4] /* ip_ttl */ + /*+ paw[5] == 0 */ /* ip_sum */ + + paw[6] /* ip_src */ + + paw[7] /* ip_src:16 */ + + paw[8] /* ip_dst */ + + paw[9]; /* ip_dst:16 */ + /* any options */ + if (pIpHdr->ip_hl > 20 / 4) + { + /* this is a bit insane... (identical to the TCP header) */ + switch (pIpHdr->ip_hl) + { + case 6: u32Sum += paw[10] + paw[11]; break; + case 7: u32Sum += paw[10] + paw[11] + paw[12] + paw[13]; break; + case 8: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15]; break; + case 9: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17]; break; + case 10: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19]; break; + case 11: u32Sum += 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: u32Sum += 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: u32Sum += 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: u32Sum += 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: u32Sum += 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 */ + u32Sum = (u32Sum >> 16) + (u32Sum & 0xffff); /* hi + low words */ + u32Sum += u32Sum >> 16; /* carry */ + return (uint16_t)~u32Sum; +} +RT_EXPORT_SYMBOL(RTNetIPv4HdrChecksum); + + +/** + * 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. + * @param fChecksum Whether to validate the checksum (GSO). + */ +RTDECL(bool) RTNetIPv4IsHdrValid(PCRTNETIPV4 pIpHdr, size_t cbHdrMax, size_t cbPktMax, bool fChecksum) +{ + /* + * The header fields. + */ + Assert(cbPktMax >= cbHdrMax); + if (RT_UNLIKELY(cbHdrMax < RTNETIPV4_MIN_LEN)) + return false; + if (RT_UNLIKELY(pIpHdr->ip_hl * 4 < RTNETIPV4_MIN_LEN)) + return false; + if (RT_UNLIKELY((size_t)pIpHdr->ip_hl * 4 > cbHdrMax)) + { + Assert((size_t)pIpHdr->ip_hl * 4 > cbPktMax); /* You'll hit this if you mapped/copy too little of the header! */ + return false; + } + if (RT_UNLIKELY(pIpHdr->ip_v != 4)) + return false; + if (RT_UNLIKELY(RT_BE2H_U16(pIpHdr->ip_len) > cbPktMax)) + return false; + + /* + * The header checksum if requested. + */ + if (fChecksum) + { + uint16_t u16Sum = RTNetIPv4HdrChecksum(pIpHdr); + if (RT_UNLIKELY(pIpHdr->ip_sum != u16Sum)) + return false; + } + return true; +} +RT_EXPORT_SYMBOL(RTNetIPv4IsHdrValid); + + +/** + * 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)). + */ +DECLINLINE(uint32_t) rtNetIPv4PseudoChecksum(PCRTNETIPV4 pIpHdr) +{ + uint16_t cbPayload = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4; + uint32_t u32Sum = pIpHdr->ip_src.au16[0] + + pIpHdr->ip_src.au16[1] + + pIpHdr->ip_dst.au16[0] + + pIpHdr->ip_dst.au16[1] +#ifdef RT_BIG_ENDIAN + + pIpHdr->ip_p +#else + + ((uint32_t)pIpHdr->ip_p << 8) +#endif + + RT_H2BE_U16(cbPayload); + return u32Sum; +} + + +/** + * 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)). + */ +RTDECL(uint32_t) RTNetIPv4PseudoChecksum(PCRTNETIPV4 pIpHdr) +{ + return rtNetIPv4PseudoChecksum(pIpHdr); +} +RT_EXPORT_SYMBOL(RTNetIPv4PseudoChecksum); + + +/** + * 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) +{ + uint32_t u32Sum = RT_H2BE_U16(SrcAddr.au16[0]) + + RT_H2BE_U16(SrcAddr.au16[1]) + + RT_H2BE_U16(DstAddr.au16[0]) + + RT_H2BE_U16(DstAddr.au16[1]) +#ifdef RT_BIG_ENDIAN + + bProtocol +#else + + ((uint32_t)bProtocol << 8) +#endif + + RT_H2BE_U16(cbPkt); + return u32Sum; +} +RT_EXPORT_SYMBOL(RTNetIPv4PseudoChecksumBits); + + +/** + * 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 u32Sum The 32-bit intermediate checksum value. + */ +DECLINLINE(uint32_t) rtNetIPv4AddUDPChecksum(PCRTNETUDP pUdpHdr, uint32_t u32Sum) +{ + u32Sum += pUdpHdr->uh_sport + + pUdpHdr->uh_dport + /*+ pUdpHdr->uh_sum = 0 */ + + pUdpHdr->uh_ulen; + return u32Sum; +} + + +/** + * 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 u32Sum The 32-bit intermediate checksum value. + */ +RTDECL(uint32_t) RTNetIPv4AddUDPChecksum(PCRTNETUDP pUdpHdr, uint32_t u32Sum) +{ + return rtNetIPv4AddUDPChecksum(pUdpHdr, u32Sum); +} +RT_EXPORT_SYMBOL(RTNetIPv4AddUDPChecksum); + + +/** + * Adds the checksum of the TCP header to the intermediate checksum value [inlined]. + * + * @returns 32-bit intermediary checksum value. + * @param pTcpHdr Pointer to the TCP header to checksum, network + * endian (big). Assumes the caller has already validate + * it and made sure the entire header is present. + * @param u32Sum The 32-bit intermediate checksum value. + */ +DECLINLINE(uint32_t) rtNetIPv4AddTCPChecksum(PCRTNETTCP pTcpHdr, uint32_t u32Sum) +{ + uint16_t const *paw = (uint16_t const *)pTcpHdr; + u32Sum += paw[0] /* th_sport */ + + paw[1] /* th_dport */ + + paw[2] /* th_seq */ + + paw[3] /* th_seq:16 */ + + paw[4] /* th_ack */ + + paw[5] /* th_ack:16 */ + + paw[6] /* th_off, th_x2, th_flags */ + + paw[7] /* th_win */ + /*+ paw[8] == 0 */ /* th_sum */ + + paw[9]; /* th_urp */ + if (pTcpHdr->th_off > RTNETTCP_MIN_LEN / 4) + { + /* this is a bit insane... (identical to the IPv4 header) */ + switch (pTcpHdr->th_off) + { + case 6: u32Sum += paw[10] + paw[11]; break; + case 7: u32Sum += paw[10] + paw[11] + paw[12] + paw[13]; break; + case 8: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15]; break; + case 9: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17]; break; + case 10: u32Sum += paw[10] + paw[11] + paw[12] + paw[13] + paw[14] + paw[15] + paw[16] + paw[17] + paw[18] + paw[19]; break; + case 11: u32Sum += 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: u32Sum += 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: u32Sum += 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: u32Sum += 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: u32Sum += 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 u32Sum; +} + + +/** + * Adds the checksum of the TCP header to the intermediate checksum value. + * + * @returns 32-bit intermediary checksum value. + * @param pTcpHdr Pointer to the TCP header to checksum, network + * endian (big). Assumes the caller has already validate + * it and made sure the entire header is present. + * @param u32Sum The 32-bit intermediate checksum value. + */ +RTDECL(uint32_t) RTNetIPv4AddTCPChecksum(PCRTNETTCP pTcpHdr, uint32_t u32Sum) +{ + return rtNetIPv4AddTCPChecksum(pTcpHdr, u32Sum); +} +RT_EXPORT_SYMBOL(RTNetIPv4AddTCPChecksum); + + +/** + * Adds the checksum of the specified data segment to the intermediate checksum value [inlined]. + * + * @returns 32-bit intermediary checksum value. + * @param pvData Pointer to the data that should be checksummed. + * @param cbData The number of bytes to checksum. + * @param u32Sum 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 u32Sum, bool *pfOdd) +{ + if (*pfOdd) + { +#ifdef RT_BIG_ENDIAN + /* there was an odd byte in the previous chunk, add the lower byte. */ + u32Sum += *(uint8_t *)pvData; +#else + /* there was an odd byte in the previous chunk, add the upper byte. */ + u32Sum += (uint32_t)*(uint8_t *)pvData << 8; +#endif + /* skip the byte. */ + cbData--; + if (!cbData) + return u32Sum; + pvData = (uint8_t const *)pvData + 1; + } + + /* iterate the data. */ + uint16_t const *pw = (uint16_t const *)pvData; + while (cbData > 1) + { + u32Sum += *pw; + pw++; + cbData -= 2; + } + + /* handle odd byte. */ + if (cbData) + { +#ifdef RT_BIG_ENDIAN + u32Sum += (uint32_t)*(uint8_t *)pw << 8; +#else + u32Sum += *(uint8_t *)pw; +#endif + *pfOdd = true; + } + else + *pfOdd = false; + return u32Sum; +} + +/** + * Adds the checksum of the specified data segment to the intermediate checksum value. + * + * @returns 32-bit intermediary checksum value. + * @param pvData The data bits to checksum. + * @param cbData The number of bytes to checksum. + * @param u32Sum 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 u32Sum, bool *pfOdd) +{ + return rtNetIPv4AddDataChecksum(pvData, cbData, u32Sum, pfOdd); +} +RT_EXPORT_SYMBOL(RTNetIPv4AddDataChecksum); + + +/** + * Finalizes a IPv4 checksum [inlined]. + * + * @returns The checksum (network endian). + * @param u32Sum The 32-bit intermediate checksum value. + */ +DECLINLINE(uint16_t) rtNetIPv4FinalizeChecksum(uint32_t u32Sum) +{ + /* 16-bit one complement fun */ + u32Sum = (u32Sum >> 16) + (u32Sum & 0xffff); /* hi + low words */ + u32Sum += u32Sum >> 16; /* carry */ + return (uint16_t)~u32Sum; +} + + +/** + * Finalizes a IPv4 checksum. + * + * @returns The checksum (network endian). + * @param u32Sum The 32-bit intermediate checksum value. + */ +RTDECL(uint16_t) RTNetIPv4FinalizeChecksum(uint32_t u32Sum) +{ + return rtNetIPv4FinalizeChecksum(u32Sum); +} +RT_EXPORT_SYMBOL(RTNetIPv4FinalizeChecksum); + + +/** + * Calculates the checksum for the UDP header given the UDP header w/ payload + * and the checksum of the pseudo header. + * + * @returns The checksum (network endian). + * @param u32Sum The checksum of the pseudo header. See + * RTNetIPv4PseudoChecksum and RTNetIPv6PseudoChecksum. + * @param pUdpHdr Pointer to the UDP header and the payload, in + * network endian (big). We use the uh_ulen field to + * figure out how much to checksum. + */ +RTDECL(uint16_t) RTNetUDPChecksum(uint32_t u32Sum, PCRTNETUDP pUdpHdr) +{ + bool fOdd; + u32Sum = rtNetIPv4AddUDPChecksum(pUdpHdr, u32Sum); + fOdd = false; + u32Sum = rtNetIPv4AddDataChecksum(pUdpHdr + 1, RT_BE2H_U16(pUdpHdr->uh_ulen) - sizeof(*pUdpHdr), u32Sum, &fOdd); + return rtNetIPv4FinalizeChecksum(u32Sum); +} +RT_EXPORT_SYMBOL(RTNetUDPChecksum); + + +/** + * Calculates the checksum for the UDP header given the IP header, + * UDP header and payload. + * + * @returns The checksum (network endian). + * @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. + */ +RTDECL(uint16_t) RTNetIPv4UDPChecksum(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, void const *pvData) +{ + bool fOdd; + uint32_t u32Sum = rtNetIPv4PseudoChecksum(pIpHdr); + u32Sum = rtNetIPv4AddUDPChecksum(pUdpHdr, u32Sum); + fOdd = false; + u32Sum = rtNetIPv4AddDataChecksum(pvData, RT_BE2H_U16(pUdpHdr->uh_ulen) - sizeof(*pUdpHdr), u32Sum, &fOdd); + return rtNetIPv4FinalizeChecksum(u32Sum); +} +RT_EXPORT_SYMBOL(RTNetIPv4UDPChecksum); + + +/** + * Simple verification of an UDP packet size. + * + * @returns true if valid, false if invalid. + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * This is assumed to be valid and the minimum size being mapped. + * @param pUdpHdr Pointer to the UDP header, in network endian (big). + * @param cbPktMax The max UDP packet size, UDP header and payload (data). + */ +DECLINLINE(bool) rtNetIPv4IsUDPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, size_t cbPktMax) +{ + /* + * Size validation. + */ + size_t cb; + if (RT_UNLIKELY(cbPktMax < RTNETUDP_MIN_LEN)) + return false; + cb = RT_BE2H_U16(pUdpHdr->uh_ulen); + if (RT_UNLIKELY(cb > cbPktMax)) + return false; + if (RT_UNLIKELY(cb > (size_t)(RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4))) + return false; + return true; +} + + +/** + * Simple verification of an UDP packet size. + * + * @returns true if valid, false if invalid. + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * This is assumed to be valid and the minimum size being mapped. + * @param pUdpHdr Pointer to the UDP header, in network endian (big). + * @param cbPktMax The max UDP packet size, UDP header and payload (data). + */ +RTDECL(bool) RTNetIPv4IsUDPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, size_t cbPktMax) +{ + return rtNetIPv4IsUDPSizeValid(pIpHdr, pUdpHdr, cbPktMax); +} +RT_EXPORT_SYMBOL(RTNetIPv4IsUDPSizeValid); + + +/** + * Simple verification of an UDP packet (size + checksum). + * + * @returns true if valid, false if invalid. + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * This is assumed to be valid and the minimum size being mapped. + * @param pUdpHdr Pointer to the UDP header, in network endian (big). + * @param pvData Pointer to the data, assuming it's one single segment + * and that cbPktMax - sizeof(RTNETUDP) is mapped here. + * @param cbPktMax The max UDP packet size, UDP header and payload (data). + * @param fChecksum Whether to validate the checksum (GSO). + */ +RTDECL(bool) RTNetIPv4IsUDPValid(PCRTNETIPV4 pIpHdr, PCRTNETUDP pUdpHdr, void const *pvData, size_t cbPktMax, bool fChecksum) +{ + if (RT_UNLIKELY(!rtNetIPv4IsUDPSizeValid(pIpHdr, pUdpHdr, cbPktMax))) + return false; + if (fChecksum && pUdpHdr->uh_sum) + { + uint16_t u16Sum = RTNetIPv4UDPChecksum(pIpHdr, pUdpHdr, pvData); + if (RT_UNLIKELY(pUdpHdr->uh_sum != u16Sum)) + return false; + } + return true; +} +RT_EXPORT_SYMBOL(RTNetIPv4IsUDPValid); + + +/** + * Calculates the checksum for the TCP header given the IP header, + * TCP header and payload. + * + * @returns The checksum (network endian). + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * @param pTcpHdr Pointer to the TCP header, in network endian (big). + * @param pvData Pointer to the TCP payload. The size is derived from + * the two headers and the caller is supposed to have + * validated this before calling. If NULL, we assume + * the data follows immediately after the TCP header. + */ +RTDECL(uint16_t) RTNetIPv4TCPChecksum(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, void const *pvData) +{ + bool fOdd; + size_t cbData; + uint32_t u32Sum = rtNetIPv4PseudoChecksum(pIpHdr); + u32Sum = rtNetIPv4AddTCPChecksum(pTcpHdr, u32Sum); + fOdd = false; + cbData = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4 - pTcpHdr->th_off * 4; + u32Sum = rtNetIPv4AddDataChecksum(pvData ? pvData : (uint8_t const *)pTcpHdr + pTcpHdr->th_off * 4, + cbData, u32Sum, &fOdd); + return rtNetIPv4FinalizeChecksum(u32Sum); +} +RT_EXPORT_SYMBOL(RTNetIPv4TCPChecksum); + + +/** + * Calculates the checksum for the TCP header given the TCP header, payload and + * the checksum of the pseudo header. + * + * This is not specific to IPv4. + * + * @returns The checksum (network endian). + * @param u32Sum The checksum of the pseudo header. See + * RTNetIPv4PseudoChecksum and RTNetIPv6PseudoChecksum. + * @param pTcpHdr Pointer to the TCP header, in network endian (big). + * @param pvData Pointer to the TCP payload. + * @param cbData The size of the TCP payload. + */ +RTDECL(uint16_t) RTNetTCPChecksum(uint32_t u32Sum, PCRTNETTCP pTcpHdr, void const *pvData, size_t cbData) +{ + bool fOdd; + u32Sum = rtNetIPv4AddTCPChecksum(pTcpHdr, u32Sum); + fOdd = false; + u32Sum = rtNetIPv4AddDataChecksum(pvData, cbData, u32Sum, &fOdd); + return rtNetIPv4FinalizeChecksum(u32Sum); +} +RT_EXPORT_SYMBOL(RTNetTCPChecksum); + + +/** + * Verification of a TCP header. + * + * @returns true if valid, false if invalid. + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * This is assumed to be valid and the minimum size being mapped. + * @param pTcpHdr Pointer to the TCP header, in network endian (big). + * @param cbHdrMax The max TCP header size (what pTcpHdr points to). + * @param cbPktMax The max TCP packet size, TCP header and payload (data). + */ +DECLINLINE(bool) rtNetIPv4IsTCPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, size_t cbPktMax) +{ + size_t cbTcpHdr; + size_t cbTcp; + + Assert(cbPktMax >= cbHdrMax); + + /* + * Size validations. + */ + if (RT_UNLIKELY(cbPktMax < RTNETTCP_MIN_LEN)) + return false; + cbTcpHdr = pTcpHdr->th_off * 4; + if (RT_UNLIKELY(cbTcpHdr > cbHdrMax)) + return false; + cbTcp = RT_BE2H_U16(pIpHdr->ip_len) - pIpHdr->ip_hl * 4; + if (RT_UNLIKELY(cbTcp > cbPktMax)) + return false; + return true; +} + + +/** + * Simple verification of an TCP packet size. + * + * @returns true if valid, false if invalid. + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * This is assumed to be valid and the minimum size being mapped. + * @param pTcpHdr Pointer to the TCP header, in network endian (big). + * @param cbHdrMax The max TCP header size (what pTcpHdr points to). + * @param cbPktMax The max TCP packet size, TCP header and payload (data). + */ +RTDECL(bool) RTNetIPv4IsTCPSizeValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, size_t cbPktMax) +{ + return rtNetIPv4IsTCPSizeValid(pIpHdr, pTcpHdr, cbHdrMax, cbPktMax); +} +RT_EXPORT_SYMBOL(RTNetIPv4IsTCPSizeValid); + + +/** + * Simple verification of an TCP packet (size + checksum). + * + * @returns true if valid, false if invalid. + * @param pIpHdr Pointer to the IPv4 header, in network endian (big). + * This is assumed to be valid and the minimum size being mapped. + * @param pTcpHdr Pointer to the TCP header, in network endian (big). + * @param cbHdrMax The max TCP header size (what pTcpHdr points to). + * @param pvData Pointer to the data, assuming it's one single segment + * and that cbPktMax - sizeof(RTNETTCP) is mapped here. + * If NULL then we assume the data follows immediately after + * the TCP header. + * @param cbPktMax The max TCP packet size, TCP header and payload (data). + * @param fChecksum Whether to validate the checksum (GSO). + */ +RTDECL(bool) RTNetIPv4IsTCPValid(PCRTNETIPV4 pIpHdr, PCRTNETTCP pTcpHdr, size_t cbHdrMax, void const *pvData, size_t cbPktMax, + bool fChecksum) +{ + if (RT_UNLIKELY(!rtNetIPv4IsTCPSizeValid(pIpHdr, pTcpHdr, cbHdrMax, cbPktMax))) + return false; + if (fChecksum) + { + uint16_t u16Sum = RTNetIPv4TCPChecksum(pIpHdr, pTcpHdr, pvData); + if (RT_UNLIKELY(pTcpHdr->th_sum != u16Sum)) + return false; + } + return true; +} +RT_EXPORT_SYMBOL(RTNetIPv4IsTCPValid); + + +/** + * Minimal validation of a DHCP packet. + * + * This will fail on BOOTP packets (if sufficient data is supplied). + * It will not verify the source and destination ports, that's the + * caller's responsibility. + * + * This function will ASSUME that the hardware type is ethernet + * and use that for htype/hlen validation. + * + * @returns true if valid, false if invalid. + * @param pUdpHdr Pointer to the UDP header, in network endian (big). + * This is assumed to be valid and fully mapped. + * @param pDhcp Pointer to the DHCP packet. + * This might not be the entire thing, see cbDhcp. + * @param cbDhcp The number of valid bytes that pDhcp points to. + * @param pMsgType Where to store the message type (if found). + * This will be set to 0 if not found and on failure. + */ +RTDECL(bool) RTNetIPv4IsDHCPValid(PCRTNETUDP pUdpHdr, PCRTNETBOOTP pDhcp, size_t cbDhcp, uint8_t *pMsgType) +{ + ssize_t cbLeft; + uint8_t MsgType; + PCRTNETDHCPOPT pOpt; + NOREF(pUdpHdr); /** @todo rainy-day: Why isn't the UDP header used? */ + + AssertPtrNull(pMsgType); + if (pMsgType) + *pMsgType = 0; + + /* + * Validate all the header fields we're able to... + */ + if (cbDhcp < RT_UOFFSETOF(RTNETBOOTP, bp_op) + sizeof(pDhcp->bp_op)) + return true; + if (RT_UNLIKELY( pDhcp->bp_op != RTNETBOOTP_OP_REQUEST + && pDhcp->bp_op != RTNETBOOTP_OP_REPLY)) + return false; + + if (cbDhcp < RT_UOFFSETOF(RTNETBOOTP, bp_htype) + sizeof(pDhcp->bp_htype)) + return true; + if (RT_UNLIKELY(pDhcp->bp_htype != RTNET_ARP_ETHER)) + return false; + + if (cbDhcp < RT_UOFFSETOF(RTNETBOOTP, bp_hlen) + sizeof(pDhcp->bp_hlen)) + return true; + if (RT_UNLIKELY(pDhcp->bp_hlen != sizeof(RTMAC))) + return false; + + if (cbDhcp < RT_UOFFSETOF(RTNETBOOTP, bp_flags) + sizeof(pDhcp->bp_flags)) + return true; + if (RT_UNLIKELY(RT_BE2H_U16(pDhcp->bp_flags) & ~(RTNET_DHCP_FLAGS_NO_BROADCAST))) + return false; + + /* + * Check the DHCP cookie and make sure it isn't followed by an END option + * (because that seems to be indicating that it's BOOTP and not DHCP). + */ + cbLeft = (ssize_t)cbDhcp - RT_UOFFSETOF(RTNETBOOTP, bp_vend.Dhcp.dhcp_cookie) + sizeof(pDhcp->bp_vend.Dhcp.dhcp_cookie); + if (cbLeft < 0) + return true; + if (RT_UNLIKELY(RT_BE2H_U32(pDhcp->bp_vend.Dhcp.dhcp_cookie) != RTNET_DHCP_COOKIE)) + return false; + if (cbLeft < 1) + return true; + pOpt = (PCRTNETDHCPOPT)&pDhcp->bp_vend.Dhcp.dhcp_opts[0]; + if (pOpt->dhcp_opt == RTNET_DHCP_OPT_END) + return false; + + /* + * Scan the options until we find the message type or run out of message. + * + * We're not strict about termination (END) for many reasons, however, + * we don't accept END without MSG_TYPE. + */ + MsgType = 0; + while (cbLeft > 0) + { + if (pOpt->dhcp_opt == RTNET_DHCP_OPT_END) + { + /* Fail if no MSG_TYPE. */ + if (!MsgType) + return false; + break; + } + if (pOpt->dhcp_opt == RTNET_DHCP_OPT_PAD) + { + pOpt = (PCRTNETDHCPOPT)((uint8_t const *)pOpt + 1); + cbLeft--; + } + else + { + switch (pOpt->dhcp_opt) + { + case RTNET_DHCP_OPT_MSG_TYPE: + { + if (cbLeft < 3) + return true; + MsgType = *(const uint8_t *)(pOpt + 1); + switch (MsgType) + { + case RTNET_DHCP_MT_DISCOVER: + case RTNET_DHCP_MT_OFFER: + case RTNET_DHCP_MT_REQUEST: + case RTNET_DHCP_MT_DECLINE: + case RTNET_DHCP_MT_ACK: + case RTNET_DHCP_MT_NAC: + case RTNET_DHCP_MT_RELEASE: + case RTNET_DHCP_MT_INFORM: + break; + + default: + /* we don't know this message type, fail. */ + return false; + } + + /* Found a known message type, consider the job done. */ + if (pMsgType) + *pMsgType = MsgType; + return true; + } + } + + /* Skip the option. */ + cbLeft -= pOpt->dhcp_len + sizeof(*pOpt); + pOpt = (PCRTNETDHCPOPT)((uint8_t const *)pOpt + pOpt->dhcp_len + sizeof(*pOpt)); + } + } + + return true; +} +RT_EXPORT_SYMBOL(RTNetIPv4IsDHCPValid); + |