1 /* 2 * IP checksumming functions. 3 * (c) 2008 Gerd Hoffmann <kraxel@redhat.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; under version 2 of the License. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see <http://www.gnu.org/licenses/>. 16 */ 17 18 #ifndef QEMU_NET_CHECKSUM_H 19 #define QEMU_NET_CHECKSUM_H 20 21 #include "qemu/bswap.h" 22 struct iovec; 23 24 uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq); 25 uint16_t net_checksum_finish(uint32_t sum); 26 uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, 27 uint8_t *addrs, uint8_t *buf); 28 void net_checksum_calculate(uint8_t *data, int length); 29 30 static inline uint32_t 31 net_checksum_add(int len, uint8_t *buf) 32 { 33 return net_checksum_add_cont(len, buf, 0); 34 } 35 36 static inline uint16_t 37 net_raw_checksum(uint8_t *data, int length) 38 { 39 return net_checksum_finish(net_checksum_add(length, data)); 40 } 41 42 /** 43 * net_checksum_add_iov: scatter-gather vector checksumming 44 * 45 * @iov: input scatter-gather array 46 * @iov_cnt: number of array elements 47 * @iov_off: starting iov offset for checksumming 48 * @size: length of data to be checksummed 49 */ 50 uint32_t net_checksum_add_iov(const struct iovec *iov, 51 const unsigned int iov_cnt, 52 uint32_t iov_off, uint32_t size); 53 54 typedef struct toeplitz_key_st { 55 uint32_t leftmost_32_bits; 56 uint8_t *next_byte; 57 } net_toeplitz_key; 58 59 static inline 60 void net_toeplitz_key_init(net_toeplitz_key *key, uint8_t *key_bytes) 61 { 62 key->leftmost_32_bits = be32_to_cpu(*(uint32_t *)key_bytes); 63 key->next_byte = key_bytes + sizeof(uint32_t); 64 } 65 66 static inline 67 void net_toeplitz_add(uint32_t *result, 68 uint8_t *input, 69 uint32_t len, 70 net_toeplitz_key *key) 71 { 72 register uint32_t accumulator = *result; 73 register uint32_t leftmost_32_bits = key->leftmost_32_bits; 74 register uint32_t byte; 75 76 for (byte = 0; byte < len; byte++) { 77 register uint8_t input_byte = input[byte]; 78 register uint8_t key_byte = *(key->next_byte++); 79 register uint8_t bit; 80 81 for (bit = 0; bit < 8; bit++) { 82 if (input_byte & (1 << 7)) { 83 accumulator ^= leftmost_32_bits; 84 } 85 86 leftmost_32_bits = 87 (leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7); 88 89 input_byte <<= 1; 90 key_byte <<= 1; 91 } 92 } 93 94 key->leftmost_32_bits = leftmost_32_bits; 95 *result = accumulator; 96 } 97 98 #endif /* QEMU_NET_CHECKSUM_H */ 99