107 lines
3.1 KiB
C
107 lines
3.1 KiB
C
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/*
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* IP checksumming functions.
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* (c) 2008 Gerd Hoffmann <kraxel@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef QEMU_NET_CHECKSUM_H
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#define QEMU_NET_CHECKSUM_H
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#include "qemu/bswap.h"
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struct iovec;
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uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq);
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uint16_t net_checksum_finish(uint32_t sum);
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uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto,
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uint8_t *addrs, uint8_t *buf);
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void net_checksum_calculate(uint8_t *data, int length);
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static inline uint32_t
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net_checksum_add(int len, uint8_t *buf)
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{
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return net_checksum_add_cont(len, buf, 0);
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}
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static inline uint16_t
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net_checksum_finish_nozero(uint32_t sum)
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{
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return net_checksum_finish(sum) ?: 0xFFFF;
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}
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static inline uint16_t
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net_raw_checksum(uint8_t *data, int length)
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{
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return net_checksum_finish(net_checksum_add(length, data));
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}
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/**
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* net_checksum_add_iov: scatter-gather vector checksumming
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*
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* @iov: input scatter-gather array
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* @iov_cnt: number of array elements
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* @iov_off: starting iov offset for checksumming
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* @size: length of data to be checksummed
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* @csum_offset: offset of the checksum chunk
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*/
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uint32_t net_checksum_add_iov(const struct iovec *iov,
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const unsigned int iov_cnt,
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uint32_t iov_off, uint32_t size,
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uint32_t csum_offset);
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typedef struct toeplitz_key_st {
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uint32_t leftmost_32_bits;
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uint8_t *next_byte;
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} net_toeplitz_key;
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static inline
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void net_toeplitz_key_init(net_toeplitz_key *key, uint8_t *key_bytes)
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{
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key->leftmost_32_bits = be32_to_cpu(*(uint32_t *)key_bytes);
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key->next_byte = key_bytes + sizeof(uint32_t);
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}
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static inline
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void net_toeplitz_add(uint32_t *result,
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uint8_t *input,
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uint32_t len,
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net_toeplitz_key *key)
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{
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register uint32_t accumulator = *result;
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register uint32_t leftmost_32_bits = key->leftmost_32_bits;
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register uint32_t byte;
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for (byte = 0; byte < len; byte++) {
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register uint8_t input_byte = input[byte];
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register uint8_t key_byte = *(key->next_byte++);
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register uint8_t bit;
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for (bit = 0; bit < 8; bit++) {
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if (input_byte & (1 << 7)) {
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accumulator ^= leftmost_32_bits;
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}
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leftmost_32_bits =
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(leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7);
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input_byte <<= 1;
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key_byte <<= 1;
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}
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}
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key->leftmost_32_bits = leftmost_32_bits;
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*result = accumulator;
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}
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#endif /* QEMU_NET_CHECKSUM_H */
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