1 #ifndef __ASM_GENERIC_CHECKSUM_H 2 #define __ASM_GENERIC_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 */ 16 extern __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 */ 25 extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum); 26 27 /* 28 * the same as csum_partial_copy, but copies from user space. 29 * 30 * here even more important to align src and dst on a 32-bit (or even 31 * better 64-bit) boundary 32 */ 33 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst, 34 int len, __wsum sum, int *csum_err); 35 36 #ifndef csum_partial_copy_nocheck 37 #define csum_partial_copy_nocheck(src, dst, len, sum) \ 38 csum_partial_copy((src), (dst), (len), (sum)) 39 #endif 40 41 #ifndef ip_fast_csum 42 /* 43 * This is a version of ip_compute_csum() optimized for IP headers, 44 * which always checksum on 4 octet boundaries. 45 */ 46 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); 47 #endif 48 49 #ifndef csum_fold 50 /* 51 * Fold a partial checksum 52 */ 53 static inline __sum16 csum_fold(__wsum csum) 54 { 55 u32 sum = (__force u32)csum; 56 sum = (sum & 0xffff) + (sum >> 16); 57 sum = (sum & 0xffff) + (sum >> 16); 58 return (__force __sum16)~sum; 59 } 60 #endif 61 62 #ifndef csum_tcpudp_nofold 63 /* 64 * computes the checksum of the TCP/UDP pseudo-header 65 * returns a 16-bit checksum, already complemented 66 */ 67 extern __wsum 68 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, 69 unsigned short proto, __wsum sum); 70 #endif 71 72 #ifndef csum_tcpudp_magic 73 static inline __sum16 74 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len, 75 unsigned short proto, __wsum sum) 76 { 77 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); 78 } 79 #endif 80 81 /* 82 * this routine is used for miscellaneous IP-like checksums, mainly 83 * in icmp.c 84 */ 85 extern __sum16 ip_compute_csum(const void *buff, int len); 86 87 #endif /* __ASM_GENERIC_CHECKSUM_H */ 88