/* * IP checksumming functions. * (c) 2008 Gerd Hoffmann <kraxel@redhat.com> * * 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; under version 2 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 <http://www.gnu.org/licenses/>. */ #ifndef QEMU_NET_CHECKSUM_H #define QEMU_NET_CHECKSUM_H #include "qemu/bswap.h" struct iovec; uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq); uint16_t net_checksum_finish(uint32_t sum); uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, uint8_t *addrs, uint8_t *buf); void net_checksum_calculate(uint8_t *data, int length); static inline uint32_t net_checksum_add(int len, uint8_t *buf) { return net_checksum_add_cont(len, buf, 0); } static inline uint16_t net_checksum_finish_nozero(uint32_t sum) { return net_checksum_finish(sum) ?: 0xFFFF; } static inline uint16_t net_raw_checksum(uint8_t *data, int length) { return net_checksum_finish(net_checksum_add(length, data)); } /** * net_checksum_add_iov: scatter-gather vector checksumming * * @iov: input scatter-gather array * @iov_cnt: number of array elements * @iov_off: starting iov offset for checksumming * @size: length of data to be checksummed * @csum_offset: offset of the checksum chunk */ uint32_t net_checksum_add_iov(const struct iovec *iov, const unsigned int iov_cnt, uint32_t iov_off, uint32_t size, uint32_t csum_offset); typedef struct toeplitz_key_st { uint32_t leftmost_32_bits; uint8_t *next_byte; } net_toeplitz_key; static inline void net_toeplitz_key_init(net_toeplitz_key *key, uint8_t *key_bytes) { key->leftmost_32_bits = be32_to_cpu(*(uint32_t *)key_bytes); key->next_byte = key_bytes + sizeof(uint32_t); } static inline void net_toeplitz_add(uint32_t *result, uint8_t *input, uint32_t len, net_toeplitz_key *key) { register uint32_t accumulator = *result; register uint32_t leftmost_32_bits = key->leftmost_32_bits; register uint32_t byte; for (byte = 0; byte < len; byte++) { register uint8_t input_byte = input[byte]; register uint8_t key_byte = *(key->next_byte++); register uint8_t bit; for (bit = 0; bit < 8; bit++) { if (input_byte & (1 << 7)) { accumulator ^= leftmost_32_bits; } leftmost_32_bits = (leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7); input_byte <<= 1; key_byte <<= 1; } } key->leftmost_32_bits = leftmost_32_bits; *result = accumulator; } #endif /* QEMU_NET_CHECKSUM_H */