Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Network checksum routines |
| 3 | * |
| 4 | * Copyright (C) 1999, 2003 Hewlett-Packard Co |
| 5 | * Stephane Eranian <eranian@hpl.hp.com> |
| 6 | * |
| 7 | * Most of the code coming from arch/alpha/lib/checksum.c |
| 8 | * |
| 9 | * This file contains network checksum routines that are better done |
| 10 | * in an architecture-specific manner due to speed.. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/string.h> |
| 15 | |
| 16 | #include <asm/byteorder.h> |
| 17 | |
| 18 | static inline unsigned short |
| 19 | from64to16 (unsigned long x) |
| 20 | { |
| 21 | /* add up 32-bit words for 33 bits */ |
| 22 | x = (x & 0xffffffff) + (x >> 32); |
| 23 | /* add up 16-bit and 17-bit words for 17+c bits */ |
| 24 | x = (x & 0xffff) + (x >> 16); |
| 25 | /* add up 16-bit and 2-bit for 16+c bit */ |
| 26 | x = (x & 0xffff) + (x >> 16); |
| 27 | /* add up carry.. */ |
| 28 | x = (x & 0xffff) + (x >> 16); |
| 29 | return x; |
| 30 | } |
| 31 | |
| 32 | /* |
| 33 | * computes the checksum of the TCP/UDP pseudo-header |
| 34 | * returns a 16-bit checksum, already complemented. |
| 35 | */ |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 36 | __sum16 |
| 37 | csum_tcpudp_magic (__be32 saddr, __be32 daddr, unsigned short len, |
| 38 | unsigned short proto, __wsum sum) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | { |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 40 | return (__force __sum16)~from64to16( |
| 41 | (__force u64)saddr + (__force u64)daddr + |
| 42 | (__force u64)sum + ((len + proto) << 8)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | } |
| 44 | |
| 45 | EXPORT_SYMBOL(csum_tcpudp_magic); |
| 46 | |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 47 | __wsum |
| 48 | csum_tcpudp_nofold (__be32 saddr, __be32 daddr, unsigned short len, |
| 49 | unsigned short proto, __wsum sum) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | { |
| 51 | unsigned long result; |
| 52 | |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 53 | result = (__force u64)saddr + (__force u64)daddr + |
| 54 | (__force u64)sum + ((len + proto) << 8); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 55 | |
| 56 | /* Fold down to 32-bits so we don't lose in the typedef-less network stack. */ |
| 57 | /* 64 to 33 */ |
| 58 | result = (result & 0xffffffff) + (result >> 32); |
| 59 | /* 33 to 32 */ |
| 60 | result = (result & 0xffffffff) + (result >> 32); |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 61 | return (__force __wsum)result; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | } |
| 63 | |
| 64 | extern unsigned long do_csum (const unsigned char *, long); |
| 65 | |
| 66 | /* |
| 67 | * computes the checksum of a memory block at buff, length len, |
| 68 | * and adds in "sum" (32-bit) |
| 69 | * |
| 70 | * returns a 32-bit number suitable for feeding into itself |
| 71 | * or csum_tcpudp_magic |
| 72 | * |
| 73 | * this function must be called with even lengths, except |
| 74 | * for the last fragment, which may be odd |
| 75 | * |
| 76 | * it's best to have buff aligned on a 32-bit boundary |
| 77 | */ |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 78 | __wsum csum_partial(const void *buff, int len, __wsum sum) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | { |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 80 | u64 result = do_csum(buff, len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | |
| 82 | /* add in old sum, and carry.. */ |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 83 | result += (__force u32)sum; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 84 | /* 32+c bits -> 32 bits */ |
| 85 | result = (result & 0xffffffff) + (result >> 32); |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 86 | return (__force __wsum)result; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | } |
| 88 | |
| 89 | EXPORT_SYMBOL(csum_partial); |
| 90 | |
| 91 | /* |
| 92 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 93 | * in icmp.c |
| 94 | */ |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 95 | __sum16 ip_compute_csum (const void *buff, int len) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | { |
Al Viro | 3225299 | 2006-11-14 21:16:30 -0800 | [diff] [blame^] | 97 | return (__force __sum16)~do_csum(buff,len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | } |
| 99 | |
| 100 | EXPORT_SYMBOL(ip_compute_csum); |