162306a36Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0 262306a36Sopenharmony_ci/* 362306a36Sopenharmony_ci * Network checksum routines 462306a36Sopenharmony_ci * 562306a36Sopenharmony_ci * Copyright (C) 1999, 2003 Hewlett-Packard Co 662306a36Sopenharmony_ci * Stephane Eranian <eranian@hpl.hp.com> 762306a36Sopenharmony_ci * 862306a36Sopenharmony_ci * Most of the code coming from arch/alpha/lib/checksum.c 962306a36Sopenharmony_ci * 1062306a36Sopenharmony_ci * This file contains network checksum routines that are better done 1162306a36Sopenharmony_ci * in an architecture-specific manner due to speed.. 1262306a36Sopenharmony_ci */ 1362306a36Sopenharmony_ci 1462306a36Sopenharmony_ci#include <linux/module.h> 1562306a36Sopenharmony_ci#include <linux/string.h> 1662306a36Sopenharmony_ci 1762306a36Sopenharmony_ci#include <asm/byteorder.h> 1862306a36Sopenharmony_ci 1962306a36Sopenharmony_cistatic inline unsigned short 2062306a36Sopenharmony_cifrom64to16 (unsigned long x) 2162306a36Sopenharmony_ci{ 2262306a36Sopenharmony_ci /* add up 32-bit words for 33 bits */ 2362306a36Sopenharmony_ci x = (x & 0xffffffff) + (x >> 32); 2462306a36Sopenharmony_ci /* add up 16-bit and 17-bit words for 17+c bits */ 2562306a36Sopenharmony_ci x = (x & 0xffff) + (x >> 16); 2662306a36Sopenharmony_ci /* add up 16-bit and 2-bit for 16+c bit */ 2762306a36Sopenharmony_ci x = (x & 0xffff) + (x >> 16); 2862306a36Sopenharmony_ci /* add up carry.. */ 2962306a36Sopenharmony_ci x = (x & 0xffff) + (x >> 16); 3062306a36Sopenharmony_ci return x; 3162306a36Sopenharmony_ci} 3262306a36Sopenharmony_ci 3362306a36Sopenharmony_ci/* 3462306a36Sopenharmony_ci * computes the checksum of the TCP/UDP pseudo-header 3562306a36Sopenharmony_ci * returns a 16-bit checksum, already complemented. 3662306a36Sopenharmony_ci */ 3762306a36Sopenharmony_ci__sum16 3862306a36Sopenharmony_cicsum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len, 3962306a36Sopenharmony_ci __u8 proto, __wsum sum) 4062306a36Sopenharmony_ci{ 4162306a36Sopenharmony_ci return (__force __sum16)~from64to16( 4262306a36Sopenharmony_ci (__force u64)saddr + (__force u64)daddr + 4362306a36Sopenharmony_ci (__force u64)sum + ((len + proto) << 8)); 4462306a36Sopenharmony_ci} 4562306a36Sopenharmony_ci 4662306a36Sopenharmony_ciEXPORT_SYMBOL(csum_tcpudp_magic); 4762306a36Sopenharmony_ci 4862306a36Sopenharmony_ci__wsum 4962306a36Sopenharmony_cicsum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len, 5062306a36Sopenharmony_ci __u8 proto, __wsum sum) 5162306a36Sopenharmony_ci{ 5262306a36Sopenharmony_ci unsigned long result; 5362306a36Sopenharmony_ci 5462306a36Sopenharmony_ci result = (__force u64)saddr + (__force u64)daddr + 5562306a36Sopenharmony_ci (__force u64)sum + ((len + proto) << 8); 5662306a36Sopenharmony_ci 5762306a36Sopenharmony_ci /* Fold down to 32-bits so we don't lose in the typedef-less network stack. */ 5862306a36Sopenharmony_ci /* 64 to 33 */ 5962306a36Sopenharmony_ci result = (result & 0xffffffff) + (result >> 32); 6062306a36Sopenharmony_ci /* 33 to 32 */ 6162306a36Sopenharmony_ci result = (result & 0xffffffff) + (result >> 32); 6262306a36Sopenharmony_ci return (__force __wsum)result; 6362306a36Sopenharmony_ci} 6462306a36Sopenharmony_ciEXPORT_SYMBOL(csum_tcpudp_nofold); 6562306a36Sopenharmony_ci 6662306a36Sopenharmony_ciextern unsigned long do_csum (const unsigned char *, long); 6762306a36Sopenharmony_ci 6862306a36Sopenharmony_ci/* 6962306a36Sopenharmony_ci * computes the checksum of a memory block at buff, length len, 7062306a36Sopenharmony_ci * and adds in "sum" (32-bit) 7162306a36Sopenharmony_ci * 7262306a36Sopenharmony_ci * returns a 32-bit number suitable for feeding into itself 7362306a36Sopenharmony_ci * or csum_tcpudp_magic 7462306a36Sopenharmony_ci * 7562306a36Sopenharmony_ci * this function must be called with even lengths, except 7662306a36Sopenharmony_ci * for the last fragment, which may be odd 7762306a36Sopenharmony_ci * 7862306a36Sopenharmony_ci * it's best to have buff aligned on a 32-bit boundary 7962306a36Sopenharmony_ci */ 8062306a36Sopenharmony_ci__wsum csum_partial(const void *buff, int len, __wsum sum) 8162306a36Sopenharmony_ci{ 8262306a36Sopenharmony_ci u64 result = do_csum(buff, len); 8362306a36Sopenharmony_ci 8462306a36Sopenharmony_ci /* add in old sum, and carry.. */ 8562306a36Sopenharmony_ci result += (__force u32)sum; 8662306a36Sopenharmony_ci /* 32+c bits -> 32 bits */ 8762306a36Sopenharmony_ci result = (result & 0xffffffff) + (result >> 32); 8862306a36Sopenharmony_ci return (__force __wsum)result; 8962306a36Sopenharmony_ci} 9062306a36Sopenharmony_ci 9162306a36Sopenharmony_ciEXPORT_SYMBOL(csum_partial); 9262306a36Sopenharmony_ci 9362306a36Sopenharmony_ci/* 9462306a36Sopenharmony_ci * this routine is used for miscellaneous IP-like checksums, mainly 9562306a36Sopenharmony_ci * in icmp.c 9662306a36Sopenharmony_ci */ 9762306a36Sopenharmony_ci__sum16 ip_compute_csum (const void *buff, int len) 9862306a36Sopenharmony_ci{ 9962306a36Sopenharmony_ci return (__force __sum16)~do_csum(buff,len); 10062306a36Sopenharmony_ci} 10162306a36Sopenharmony_ci 10262306a36Sopenharmony_ciEXPORT_SYMBOL(ip_compute_csum); 103