/* * arch/sh/lib64/c-checksum.c * * This file contains network checksum routines that are better done * in an architecture-specific manner due to speed.. */ #include <linux/string.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/module.h> #include <asm/byteorder.h> #include <asm/uaccess.h> static inline unsigned short from64to16(unsigned long long x) { /* add up 32-bit words for 33 bits */ x = (x & 0xffffffff) + (x >> 32); /* add up 16-bit and 17-bit words for 17+c bits */ x = (x & 0xffff) + (x >> 16); /* add up 16-bit and 2-bit for 16+c bit */ x = (x & 0xffff) + (x >> 16); /* add up carry.. */ x = (x & 0xffff) + (x >> 16); return x; } static inline unsigned short foldto16(unsigned long x) { /* add up 16-bit for 17 bits */ x = (x & 0xffff) + (x >> 16); /* add up carry.. */ x = (x & 0xffff) + (x >> 16); return x; } static inline unsigned short myfoldto16(unsigned long long x) { /* Fold down to 32-bits so we don't loose in the typedef-less network stack. */ /* 64 to 33 */ x = (x & 0xffffffff) + (x >> 32); /* 33 to 32 */ x = (x & 0xffffffff) + (x >> 32); /* add up 16-bit for 17 bits */ x = (x & 0xffff) + (x >> 16); /* add up carry.. */ x = (x & 0xffff) + (x >> 16); return x; } #define odd(x) ((x)&1) #define U16(x) ntohs(x) static unsigned long do_csum(const unsigned char *buff, int len) { int odd, count; unsigned long result = 0; pr_debug("do_csum buff %p, len %d (0x%x)\n", buff, len, len); #ifdef DEBUG for (i = 0; i < len; i++) { if ((i % 26) == 0) printk("\n"); printk("%02X ", buff[i]); } #endif if (len <= 0) goto out; odd = 1 & (unsigned long) buff; if (odd) { result = *buff << 8; len--; buff++; } count = len >> 1; /* nr of 16-bit words.. */ if (count) { if (2 & (unsigned long) buff) { result += *(unsigned short *) buff; count--; len -= 2; buff += 2; } count >>= 1; /* nr of 32-bit words.. */ if (count) { unsigned long carry = 0; do { unsigned long w = *(unsigned long *) buff; buff += 4; count--; result += carry; result += w; carry = (w > result); } while (count); result += carry; result = (result & 0xffff) + (result >> 16); } if (len & 2) { result += *(unsigned short *) buff; buff += 2; } } if (len & 1) result += *buff; result = foldto16(result); if (odd) result = ((result >> 8) & 0xff) | ((result & 0xff) << 8); pr_debug("\nCHECKSUM is 0x%lx\n", result); out: return result; } /* computes the checksum of a memory block at buff, length len, and adds in "sum" (32-bit) */ __wsum csum_partial(const void *buff, int len, __wsum sum) { unsigned long long result = do_csum(buff, len); /* add in old sum, and carry.. */ result += (__force u32)sum; /* 32+c bits -> 32 bits */ result = (result & 0xffffffff) + (result >> 32); pr_debug("csum_partial, buff %p len %d sum 0x%x result=0x%016Lx\n", buff, len, sum, result); return (__force __wsum)result; } /* Copy while checksumming, otherwise like csum_partial. */ __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum) { sum = csum_partial(src, len, sum); memcpy(dst, src, len); return sum; } /* Copy from userspace and compute checksum. If we catch an exception then zero the rest of the buffer. */ __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *err_ptr) { int missing; pr_debug ("csum_partial_copy_from_user src %p, dest %p, len %d, sum %08x, err_ptr %p\n", src, dst, len, sum, err_ptr); missing = copy_from_user(dst, src, len); pr_debug(" access_ok %d\n", __access_ok((unsigned long) src, len)); pr_debug(" missing %d\n", missing); if (missing) { memset(dst + len - missing, 0, missing); *err_ptr = -EFAULT; } return csum_partial(dst, len, sum); } /* Copy to userspace and compute checksum. */ __wsum csum_partial_copy_to_user(const unsigned char *src, unsigned char *dst, int len, __wsum sum, int *err_ptr) { sum = csum_partial(src, len, sum); if (copy_to_user(dst, src, len)) *err_ptr = -EFAULT; return sum; } /* * This is a version of ip_compute_csum() optimized for IP headers, * which always checksum on 4 octet boundaries. */ __sum16 ip_fast_csum(const void *iph, unsigned int ihl) { pr_debug("ip_fast_csum %p,%d\n", iph, ihl); return (__force __sum16)~do_csum(iph, ihl * 4); } __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, unsigned short proto, __wsum sum) { unsigned long long result; pr_debug("ntohs(0x%x)=0x%x\n", 0xdead, ntohs(0xdead)); pr_debug("htons(0x%x)=0x%x\n", 0xdead, htons(0xdead)); result = (__force u64) saddr + (__force u64) daddr + (__force u64) sum + ((len + proto) << 8); /* Fold down to 32-bits so we don't loose in the typedef-less network stack. */ /* 64 to 33 */ result = (result & 0xffffffff) + (result >> 32); /* 33 to 32 */ result = (result & 0xffffffff) + (result >> 32); pr_debug("%s saddr %x daddr %x len %x proto %x sum %x result %08Lx\n", __FUNCTION__, saddr, daddr, len, proto, sum, result); return (__wsum)result; } EXPORT_SYMBOL(csum_tcpudp_nofold);