| /* SPDX-License-Identifier: GPL-2.0 */ |
| #ifndef __ASM_GENERIC_CHECKSUM_H |
| #define __ASM_GENERIC_CHECKSUM_H |
| |
| /* |
| * computes the checksum of a memory block at buff, length len, |
| * and adds in "sum" (32-bit) |
| * |
| * returns a 32-bit number suitable for feeding into itself |
| * or csum_tcpudp_magic |
| * |
| * this function must be called with even lengths, except |
| * for the last fragment, which may be odd |
| * |
| * it's best to have buff aligned on a 32-bit boundary |
| */ |
| extern __wsum csum_partial(const void *buff, int len, __wsum sum); |
| |
| /* |
| * the same as csum_partial, but copies from src while it |
| * checksums |
| * |
| * here even more important to align src and dst on a 32-bit (or even |
| * better 64-bit) boundary |
| */ |
| extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum); |
| |
| #ifndef csum_partial_copy_nocheck |
| #define csum_partial_copy_nocheck(src, dst, len, sum) \ |
| csum_partial_copy((src), (dst), (len), (sum)) |
| #endif |
| |
| #ifndef ip_fast_csum |
| /* |
| * This is a version of ip_compute_csum() optimized for IP headers, |
| * which always checksum on 4 octet boundaries. |
| */ |
| extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); |
| #endif |
| |
| #ifndef csum_fold |
| /* |
| * Fold a partial checksum |
| */ |
| static inline __sum16 csum_fold(__wsum csum) |
| { |
| u32 sum = (__force u32)csum; |
| sum = (sum & 0xffff) + (sum >> 16); |
| sum = (sum & 0xffff) + (sum >> 16); |
| return (__force __sum16)~sum; |
| } |
| #endif |
| |
| #ifndef csum_tcpudp_nofold |
| /* |
| * computes the checksum of the TCP/UDP pseudo-header |
| * returns a 16-bit checksum, already complemented |
| */ |
| extern __wsum |
| csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, |
| __u8 proto, __wsum sum); |
| #endif |
| |
| #ifndef csum_tcpudp_magic |
| static inline __sum16 |
| csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, |
| __u8 proto, __wsum sum) |
| { |
| return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); |
| } |
| #endif |
| |
| /* |
| * this routine is used for miscellaneous IP-like checksums, mainly |
| * in icmp.c |
| */ |
| extern __sum16 ip_compute_csum(const void *buff, int len); |
| |
| #endif /* __ASM_GENERIC_CHECKSUM_H */ |