66 lines · c
1/* SPDX-License-Identifier: GPL-2.0 */2#ifndef __ASM_GENERIC_CHECKSUM_H3#define __ASM_GENERIC_CHECKSUM_H4 5#include <linux/bitops.h>6 7/*8 * computes the checksum of a memory block at buff, length len,9 * and adds in "sum" (32-bit)10 *11 * returns a 32-bit number suitable for feeding into itself12 * or csum_tcpudp_magic13 *14 * this function must be called with even lengths, except15 * for the last fragment, which may be odd16 *17 * it's best to have buff aligned on a 32-bit boundary18 */19extern __wsum csum_partial(const void *buff, int len, __wsum sum);20 21#ifndef ip_fast_csum22/*23 * This is a version of ip_compute_csum() optimized for IP headers,24 * which always checksum on 4 octet boundaries.25 */26extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);27#endif28 29#ifndef csum_fold30/*31 * Fold a partial checksum32 */33static inline __sum16 csum_fold(__wsum csum)34{35 u32 sum = (__force u32)csum;36 return (__force __sum16)((~sum - ror32(sum, 16)) >> 16);37}38#endif39 40#ifndef csum_tcpudp_nofold41/*42 * computes the checksum of the TCP/UDP pseudo-header43 * returns a 16-bit checksum, already complemented44 */45extern __wsum46csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,47 __u8 proto, __wsum sum);48#endif49 50#ifndef csum_tcpudp_magic51static inline __sum1652csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,53 __u8 proto, __wsum sum)54{55 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));56}57#endif58 59/*60 * this routine is used for miscellaneous IP-like checksums, mainly61 * in icmp.c62 */63extern __sum16 ip_compute_csum(const void *buff, int len);64 65#endif /* __ASM_GENERIC_CHECKSUM_H */66