checksum.h (3347B)
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 #define CSUM_IP 0x01 25 #define CSUM_TCP 0x02 26 #define CSUM_UDP 0x04 27 #define CSUM_ALL (CSUM_IP | CSUM_TCP | CSUM_UDP) 28 29 uint32_t net_checksum_add_cont(int len, uint8_t *buf, int seq); 30 uint16_t net_checksum_finish(uint32_t sum); 31 uint16_t net_checksum_tcpudp(uint16_t length, uint16_t proto, 32 uint8_t *addrs, uint8_t *buf); 33 void net_checksum_calculate(uint8_t *data, int length, int csum_flag); 34 35 static inline uint32_t 36 net_checksum_add(int len, uint8_t *buf) 37 { 38 return net_checksum_add_cont(len, buf, 0); 39 } 40 41 static inline uint16_t 42 net_checksum_finish_nozero(uint32_t sum) 43 { 44 return net_checksum_finish(sum) ?: 0xFFFF; 45 } 46 47 static inline uint16_t 48 net_raw_checksum(uint8_t *data, int length) 49 { 50 return net_checksum_finish(net_checksum_add(length, data)); 51 } 52 53 /** 54 * net_checksum_add_iov: scatter-gather vector checksumming 55 * 56 * @iov: input scatter-gather array 57 * @iov_cnt: number of array elements 58 * @iov_off: starting iov offset for checksumming 59 * @size: length of data to be checksummed 60 * @csum_offset: offset of the checksum chunk 61 */ 62 uint32_t net_checksum_add_iov(const struct iovec *iov, 63 const unsigned int iov_cnt, 64 uint32_t iov_off, uint32_t size, 65 uint32_t csum_offset); 66 67 typedef struct toeplitz_key_st { 68 uint32_t leftmost_32_bits; 69 uint8_t *next_byte; 70 } net_toeplitz_key; 71 72 static inline 73 void net_toeplitz_key_init(net_toeplitz_key *key, uint8_t *key_bytes) 74 { 75 key->leftmost_32_bits = be32_to_cpu(*(uint32_t *)key_bytes); 76 key->next_byte = key_bytes + sizeof(uint32_t); 77 } 78 79 static inline 80 void net_toeplitz_add(uint32_t *result, 81 uint8_t *input, 82 uint32_t len, 83 net_toeplitz_key *key) 84 { 85 register uint32_t accumulator = *result; 86 register uint32_t leftmost_32_bits = key->leftmost_32_bits; 87 register uint32_t byte; 88 89 for (byte = 0; byte < len; byte++) { 90 register uint8_t input_byte = input[byte]; 91 register uint8_t key_byte = *(key->next_byte++); 92 register uint8_t bit; 93 94 for (bit = 0; bit < 8; bit++) { 95 if (input_byte & (1 << 7)) { 96 accumulator ^= leftmost_32_bits; 97 } 98 99 leftmost_32_bits = 100 (leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7); 101 102 input_byte <<= 1; 103 key_byte <<= 1; 104 } 105 } 106 107 key->leftmost_32_bits = leftmost_32_bits; 108 *result = accumulator; 109 } 110 111 #endif /* QEMU_NET_CHECKSUM_H */