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