1#ifndef _METAG_CHECKSUM_H 2#define _METAG_CHECKSUM_H 3 4/* 5 * computes the checksum of a memory block at buff, length len, 6 * and adds in "sum" (32-bit) 7 * 8 * returns a 32-bit number suitable for feeding into itself 9 * or csum_tcpudp_magic 10 * 11 * this function must be called with even lengths, except 12 * for the last fragment, which may be odd 13 * 14 * it's best to have buff aligned on a 32-bit boundary 15 */ 16extern __wsum csum_partial(const void *buff, int len, __wsum sum); 17 18/* 19 * the same as csum_partial, but copies from src while it 20 * checksums 21 * 22 * here even more important to align src and dst on a 32-bit (or even 23 * better 64-bit) boundary 24 */ 25extern __wsum csum_partial_copy(const void *src, void *dst, int len, 26 __wsum sum); 27 28/* 29 * the same as csum_partial_copy, but copies from user space. 30 * 31 * here even more important to align src and dst on a 32-bit (or even 32 * better 64-bit) boundary 33 */ 34extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst, 35 int len, __wsum sum, int *csum_err); 36 37#define csum_partial_copy_nocheck(src, dst, len, sum) \ 38 csum_partial_copy((src), (dst), (len), (sum)) 39 40/* 41 * Fold a partial checksum 42 */ 43static inline __sum16 csum_fold(__wsum csum) 44{ 45 u32 sum = (__force u32)csum; 46 sum = (sum & 0xffff) + (sum >> 16); 47 sum = (sum & 0xffff) + (sum >> 16); 48 return (__force __sum16)~sum; 49} 50 51/* 52 * This is a version of ip_compute_csum() optimized for IP headers, 53 * which always checksum on 4 octet boundaries. 54 */ 55extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); 56 57/* 58 * computes the checksum of the TCP/UDP pseudo-header 59 * returns a 16-bit checksum, already complemented 60 */ 61static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 62 unsigned short len, 63 unsigned short proto, 64 __wsum sum) 65{ 66 unsigned long len_proto = (proto + len) << 8; 67 asm ("ADDS %0, %0, %1\n" 68 "ADDCS %0, %0, #1\n" 69 "ADDS %0, %0, %2\n" 70 "ADDCS %0, %0, #1\n" 71 "ADDS %0, %0, %3\n" 72 "ADDCS %0, %0, #1\n" 73 : "=d" (sum) 74 : "d" (daddr), "d" (saddr), "d" (len_proto), 75 "0" (sum) 76 : "cc"); 77 return sum; 78} 79 80static inline __sum16 81csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len, 82 unsigned short proto, __wsum sum) 83{ 84 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 85} 86 87/* 88 * this routine is used for miscellaneous IP-like checksums, mainly 89 * in icmp.c 90 */ 91extern __sum16 ip_compute_csum(const void *buff, int len); 92 93#endif /* _METAG_CHECKSUM_H */ 94