1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * Network Checksum & Copy routine 4*4882a593Smuzhiyun * 5*4882a593Smuzhiyun * Copyright (C) 1999, 2003-2004 Hewlett-Packard Co 6*4882a593Smuzhiyun * Stephane Eranian <eranian@hpl.hp.com> 7*4882a593Smuzhiyun * 8*4882a593Smuzhiyun * Most of the code has been imported from Linux/Alpha 9*4882a593Smuzhiyun */ 10*4882a593Smuzhiyun 11*4882a593Smuzhiyun #include <linux/module.h> 12*4882a593Smuzhiyun #include <linux/types.h> 13*4882a593Smuzhiyun #include <linux/string.h> 14*4882a593Smuzhiyun 15*4882a593Smuzhiyun #include <net/checksum.h> 16*4882a593Smuzhiyun 17*4882a593Smuzhiyun /* 18*4882a593Smuzhiyun * XXX Fixme: those 2 inlines are meant for debugging and will go away 19*4882a593Smuzhiyun */ 20*4882a593Smuzhiyun static inline unsigned from64to16(unsigned long x)21*4882a593Smuzhiyunshort from64to16(unsigned long x) 22*4882a593Smuzhiyun { 23*4882a593Smuzhiyun /* add up 32-bit words for 33 bits */ 24*4882a593Smuzhiyun x = (x & 0xffffffff) + (x >> 32); 25*4882a593Smuzhiyun /* add up 16-bit and 17-bit words for 17+c bits */ 26*4882a593Smuzhiyun x = (x & 0xffff) + (x >> 16); 27*4882a593Smuzhiyun /* add up 16-bit and 2-bit for 16+c bit */ 28*4882a593Smuzhiyun x = (x & 0xffff) + (x >> 16); 29*4882a593Smuzhiyun /* add up carry.. */ 30*4882a593Smuzhiyun x = (x & 0xffff) + (x >> 16); 31*4882a593Smuzhiyun return x; 32*4882a593Smuzhiyun } 33*4882a593Smuzhiyun 34*4882a593Smuzhiyun static inline do_csum_c(const unsigned char * buff,int len,unsigned int psum)35*4882a593Smuzhiyununsigned long do_csum_c(const unsigned char * buff, int len, unsigned int psum) 36*4882a593Smuzhiyun { 37*4882a593Smuzhiyun int odd, count; 38*4882a593Smuzhiyun unsigned long result = (unsigned long)psum; 39*4882a593Smuzhiyun 40*4882a593Smuzhiyun if (len <= 0) 41*4882a593Smuzhiyun goto out; 42*4882a593Smuzhiyun odd = 1 & (unsigned long) buff; 43*4882a593Smuzhiyun if (odd) { 44*4882a593Smuzhiyun result = *buff << 8; 45*4882a593Smuzhiyun len--; 46*4882a593Smuzhiyun buff++; 47*4882a593Smuzhiyun } 48*4882a593Smuzhiyun count = len >> 1; /* nr of 16-bit words.. */ 49*4882a593Smuzhiyun if (count) { 50*4882a593Smuzhiyun if (2 & (unsigned long) buff) { 51*4882a593Smuzhiyun result += *(unsigned short *) buff; 52*4882a593Smuzhiyun count--; 53*4882a593Smuzhiyun len -= 2; 54*4882a593Smuzhiyun buff += 2; 55*4882a593Smuzhiyun } 56*4882a593Smuzhiyun count >>= 1; /* nr of 32-bit words.. */ 57*4882a593Smuzhiyun if (count) { 58*4882a593Smuzhiyun if (4 & (unsigned long) buff) { 59*4882a593Smuzhiyun result += *(unsigned int *) buff; 60*4882a593Smuzhiyun count--; 61*4882a593Smuzhiyun len -= 4; 62*4882a593Smuzhiyun buff += 4; 63*4882a593Smuzhiyun } 64*4882a593Smuzhiyun count >>= 1; /* nr of 64-bit words.. */ 65*4882a593Smuzhiyun if (count) { 66*4882a593Smuzhiyun unsigned long carry = 0; 67*4882a593Smuzhiyun do { 68*4882a593Smuzhiyun unsigned long w = *(unsigned long *) buff; 69*4882a593Smuzhiyun count--; 70*4882a593Smuzhiyun buff += 8; 71*4882a593Smuzhiyun result += carry; 72*4882a593Smuzhiyun result += w; 73*4882a593Smuzhiyun carry = (w > result); 74*4882a593Smuzhiyun } while (count); 75*4882a593Smuzhiyun result += carry; 76*4882a593Smuzhiyun result = (result & 0xffffffff) + (result >> 32); 77*4882a593Smuzhiyun } 78*4882a593Smuzhiyun if (len & 4) { 79*4882a593Smuzhiyun result += *(unsigned int *) buff; 80*4882a593Smuzhiyun buff += 4; 81*4882a593Smuzhiyun } 82*4882a593Smuzhiyun } 83*4882a593Smuzhiyun if (len & 2) { 84*4882a593Smuzhiyun result += *(unsigned short *) buff; 85*4882a593Smuzhiyun buff += 2; 86*4882a593Smuzhiyun } 87*4882a593Smuzhiyun } 88*4882a593Smuzhiyun if (len & 1) 89*4882a593Smuzhiyun result += *buff; 90*4882a593Smuzhiyun 91*4882a593Smuzhiyun result = from64to16(result); 92*4882a593Smuzhiyun 93*4882a593Smuzhiyun if (odd) 94*4882a593Smuzhiyun result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); 95*4882a593Smuzhiyun 96*4882a593Smuzhiyun out: 97*4882a593Smuzhiyun return result; 98*4882a593Smuzhiyun } 99