1 #ifndef _ASM_POWERPC_CHECKSUM_H 2 #define _ASM_POWERPC_CHECKSUM_H 3 #ifdef __KERNEL__ 4 5 /* 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 /* 13 * This is a version of ip_compute_csum() optimized for IP headers, 14 * which always checksum on 4 octet boundaries. ihl is the number 15 * of 32-bit words and is always >= 5. 16 */ 17 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); 18 19 /* 20 * computes the checksum of the TCP/UDP pseudo-header 21 * returns a 16-bit checksum, already complemented 22 */ 23 extern __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 24 unsigned short len, 25 unsigned short proto, 26 __wsum 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 __wsum csum_partial(const void *buff, int len, __wsum sum); 41 42 /* 43 * Computes the checksum of a memory block at src, length len, 44 * and adds in "sum" (32-bit), while copying the block to dst. 45 * If an access exception occurs on src or dst, it stores -EFAULT 46 * to *src_err or *dst_err respectively (if that pointer is not 47 * NULL), and, for an error on src, zeroes the rest of dst. 48 * 49 * Like csum_partial, this must be called with even lengths, 50 * except for the last fragment. 51 */ 52 extern __wsum csum_partial_copy_generic(const void *src, void *dst, 53 int len, __wsum sum, 54 int *src_err, int *dst_err); 55 /* 56 * the same as csum_partial, but copies from src to dst while it 57 * checksums. 58 */ 59 #define csum_partial_copy_from_user(src, dst, len, sum, errp) \ 60 csum_partial_copy_generic((__force const void *)(src), (dst), (len), (sum), (errp), NULL) 61 62 #define csum_partial_copy_nocheck(src, dst, len, sum) \ 63 csum_partial_copy_generic((src), (dst), (len), (sum), NULL, NULL) 64 65 66 /* 67 * turns a 32-bit partial checksum (e.g. from csum_partial) into a 68 * 1's complement 16-bit checksum. 69 */ 70 static inline __sum16 csum_fold(__wsum sum) 71 { 72 unsigned int tmp; 73 74 /* swap the two 16-bit halves of sum */ 75 __asm__("rlwinm %0,%1,16,0,31" : "=r" (tmp) : "r" (sum)); 76 /* if there is a carry from adding the two 16-bit halves, 77 it will carry from the lower half into the upper half, 78 giving us the correct sum in the upper half. */ 79 return (__force __sum16)(~((__force u32)sum + tmp) >> 16); 80 } 81 82 /* 83 * this routine is used for miscellaneous IP-like checksums, mainly 84 * in icmp.c 85 */ 86 static inline __sum16 ip_compute_csum(const void *buff, int len) 87 { 88 return csum_fold(csum_partial(buff, len, 0)); 89 } 90 91 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 92 unsigned short len, 93 unsigned short proto, 94 __wsum sum) 95 { 96 #ifdef __powerpc64__ 97 unsigned long s = (__force u32)sum; 98 99 s += (__force u32)saddr; 100 s += (__force u32)daddr; 101 s += proto + len; 102 s += (s >> 32); 103 return (__force __wsum) s; 104 #else 105 __asm__("\n\ 106 addc %0,%0,%1 \n\ 107 adde %0,%0,%2 \n\ 108 adde %0,%0,%3 \n\ 109 addze %0,%0 \n\ 110 " 111 : "=r" (sum) 112 : "r" (daddr), "r"(saddr), "r"(proto + len), "0"(sum)); 113 return sum; 114 #endif 115 } 116 #endif /* __KERNEL__ */ 117 #endif 118