1 /* 2 * Copyright (C) 2016 ARM Ltd. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public License 14 * along with this program. If not, see <http://www.gnu.org/licenses/>. 15 */ 16 #ifndef __ASM_CHECKSUM_H 17 #define __ASM_CHECKSUM_H 18 19 #include <linux/types.h> 20 21 static inline __sum16 csum_fold(__wsum csum) 22 { 23 u32 sum = (__force u32)csum; 24 sum += (sum >> 16) | (sum << 16); 25 return ~(__force __sum16)(sum >> 16); 26 } 27 #define csum_fold csum_fold 28 29 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 30 { 31 __uint128_t tmp; 32 u64 sum; 33 34 tmp = *(const __uint128_t *)iph; 35 iph += 16; 36 ihl -= 4; 37 tmp += ((tmp >> 64) | (tmp << 64)); 38 sum = tmp >> 64; 39 do { 40 sum += *(const u32 *)iph; 41 iph += 4; 42 } while (--ihl); 43 44 sum += ((sum >> 32) | (sum << 32)); 45 return csum_fold(sum >> 32); 46 } 47 #define ip_fast_csum ip_fast_csum 48 49 #include <asm-generic/checksum.h> 50 51 #endif /* __ASM_CHECKSUM_H */ 52