| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _PPC64_CHECKSUM_H |
| 2 | #define _PPC64_CHECKSUM_H |
| 3 | |
| 4 | /* |
| 5 | * This program is free software; you can redistribute it and/or |
| 6 | * modify it under the terms of the GNU General Public License |
| 7 | * as published by the Free Software Foundation; either version |
| 8 | * 2 of the License, or (at your option) any later version. |
| 9 | */ |
| 10 | |
| 11 | /* |
| 12 | * This is a version of ip_compute_csum() optimized for IP headers, |
| 13 | * which always checksum on 4 octet boundaries. ihl is the number |
| 14 | * of 32-bit words and is always >= 5. |
| 15 | */ |
| 16 | extern unsigned short ip_fast_csum(unsigned char * iph, unsigned int ihl); |
| 17 | |
| 18 | /* |
| 19 | * computes the checksum of the TCP/UDP pseudo-header |
| 20 | * returns a 16-bit checksum, already complemented |
| 21 | */ |
| 22 | extern unsigned short csum_tcpudp_magic(unsigned long saddr, |
| 23 | unsigned long daddr, |
| 24 | unsigned short len, |
| 25 | unsigned short proto, |
| 26 | unsigned int sum); |
| 27 | |
| 28 | /* |
| 29 | * computes the checksum of a memory block at buff, length len, |
| 30 | * and adds in "sum" (32-bit) |
| 31 | * |
| 32 | * returns a 32-bit number suitable for feeding into itself |
| 33 | * or csum_tcpudp_magic |
| 34 | * |
| 35 | * this function must be called with even lengths, except |
| 36 | * for the last fragment, which may be odd |
| 37 | * |
| 38 | * it's best to have buff aligned on a 32-bit boundary |
| 39 | */ |
| 40 | extern unsigned int csum_partial(const unsigned char * buff, int len, |
| 41 | unsigned int sum); |
| 42 | |
| 43 | /* |
| 44 | * the same as csum_partial, but copies from src to dst while it |
| 45 | * checksums |
| 46 | */ |
| 47 | extern unsigned int csum_partial_copy_generic(const char *src, char *dst, |
| 48 | int len, unsigned int sum, |
| 49 | int *src_err, int *dst_err); |
| 50 | /* |
| 51 | * the same as csum_partial, but copies from src to dst while it |
| 52 | * checksums. |
| 53 | */ |
| 54 | |
| 55 | unsigned int csum_partial_copy_nocheck(const char *src, |
| 56 | char *dst, |
| 57 | int len, |
| 58 | unsigned int sum); |
| 59 | |
| 60 | /* |
| 61 | * turns a 32-bit partial checksum (e.g. from csum_partial) into a |
| 62 | * 1's complement 16-bit checksum. |
| 63 | */ |
| 64 | static inline unsigned int csum_fold(unsigned int sum) |
| 65 | { |
| 66 | unsigned int tmp; |
| 67 | |
| 68 | /* swap the two 16-bit halves of sum */ |
| 69 | __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); |
| 70 | /* if there is a carry from adding the two 16-bit halves, |
| 71 | it will carry from the lower half into the upper half, |
| 72 | giving us the correct sum in the upper half. */ |
| 73 | sum = ~(sum + tmp) >> 16; |
| 74 | return sum; |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 79 | * in icmp.c |
| 80 | */ |
| 81 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) |
| 82 | { |
| 83 | return csum_fold(csum_partial(buff, len, 0)); |
| 84 | } |
| 85 | |
| 86 | #define csum_partial_copy_from_user(src, dst, len, sum, errp) \ |
| 87 | csum_partial_copy_generic((src), (dst), (len), (sum), (errp), NULL) |
| 88 | |
| 89 | #define csum_partial_copy_nocheck(src, dst, len, sum) \ |
| 90 | csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL) |
| 91 | |
| 92 | static inline u32 csum_tcpudp_nofold(u32 saddr, |
| 93 | u32 daddr, |
| 94 | unsigned short len, |
| 95 | unsigned short proto, |
| 96 | unsigned int sum) |
| 97 | { |
| 98 | unsigned long s = sum; |
| 99 | |
| 100 | s += saddr; |
| 101 | s += daddr; |
| 102 | s += (proto << 16) + len; |
| 103 | s += (s >> 32); |
| 104 | return (u32) s; |
| 105 | } |
| 106 | |
| 107 | #endif |