mirror of
https://github.com/mfontanini/libtins
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132 lines
4.3 KiB
C++
132 lines
4.3 KiB
C++
/*
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* Copyright (c) 2017, Matias Fontanini
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "utils/checksum_utils.h"
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#include <cstring>
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#include "ip_address.h"
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#include "ipv6_address.h"
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#include "endianness.h"
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#include "memory_helpers.h"
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using std::memcpy;
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using Tins::Memory::InputMemoryStream;
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using Tins::Memory::OutputMemoryStream;
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namespace Tins {
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namespace Utils {
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uint32_t do_checksum(const uint8_t* start, const uint8_t* end) {
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return Endian::host_to_be<uint32_t>(sum_range(start, end));
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}
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uint16_t sum_range(const uint8_t* start, const uint8_t* end) {
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uint32_t checksum(0);
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const uint8_t* last = end;
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uint16_t buffer = 0;
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uint16_t padding = 0;
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const uint8_t* ptr = start;
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if (((end - start) & 1) == 1) {
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last = end - 1;
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padding = Endian::host_to_le<uint16_t>(*(end - 1));
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}
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while (ptr < last) {
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memcpy(&buffer, ptr, sizeof(uint16_t));
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checksum += buffer;
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ptr += sizeof(uint16_t);
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}
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checksum += padding;
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while (checksum >> 16) {
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checksum = (checksum & 0xffff) + (checksum >> 16);
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}
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return checksum;
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}
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template <size_t buffer_size, typename AddressType>
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uint32_t generic_pseudoheader_checksum(const AddressType& source_ip,
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const AddressType& dest_ip,
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uint16_t len,
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uint16_t flag) {
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uint8_t buffer[buffer_size];
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OutputMemoryStream stream(buffer, sizeof(buffer));
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stream.write(source_ip);
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stream.write(dest_ip);
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stream.write(Endian::host_to_be(flag));
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stream.write(Endian::host_to_be(len));
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InputMemoryStream input_stream(buffer, sizeof(buffer));
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uint32_t checksum = 0;
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while (input_stream) {
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checksum += input_stream.read<uint16_t>();
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}
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return checksum;
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}
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uint32_t pseudoheader_checksum(IPv4Address source_ip,
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IPv4Address dest_ip,
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uint16_t len,
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uint16_t flag) {
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return generic_pseudoheader_checksum<sizeof(uint32_t) * 3>(
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source_ip, dest_ip, len, flag
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);
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}
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uint32_t pseudoheader_checksum(IPv6Address source_ip,
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IPv6Address dest_ip,
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uint16_t len,
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uint16_t flag) {
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return generic_pseudoheader_checksum<IPv6Address::address_size * 2 + sizeof(uint16_t) * 2>(
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source_ip, dest_ip, len, flag
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);
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}
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uint32_t crc32(const uint8_t* data, uint32_t data_size) {
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uint32_t i, crc = 0;
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static uint32_t crc_table[] = {
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0x4DBDF21C, 0x500AE278, 0x76D3D2D4, 0x6B64C2B0,
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0x3B61B38C, 0x26D6A3E8, 0x000F9344, 0x1DB88320,
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0xA005713C, 0xBDB26158, 0x9B6B51F4, 0x86DC4190,
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0xD6D930AC, 0xCB6E20C8, 0xEDB71064, 0xF0000000
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};
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for (i = 0; i < data_size; ++i) {
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crc = (crc >> 4) ^ crc_table[(crc ^ data[i]) & 0x0F];
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crc = (crc >> 4) ^ crc_table[(crc ^ (data[i] >> 4)) & 0x0F];
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}
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return crc;
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}
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} // Utils
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} // Tins
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