| Arnd Bergmann | 26a28fa | 2009-05-13 22:56:38 +0000 | [diff] [blame] | 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 | #define csum_partial_copy_nocheck(src, dst, len, sum) \ |
| 37 | csum_partial_copy((src), (dst), (len), (sum)) |
| 38 | |
| 39 | /* |
| 40 | * This is a version of ip_compute_csum() optimized for IP headers, |
| 41 | * which always checksum on 4 octet boundaries. |
| 42 | */ |
| 43 | extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); |
| 44 | |
| 45 | /* |
| 46 | * Fold a partial checksum |
| 47 | */ |
| 48 | static inline __sum16 csum_fold(__wsum csum) |
| 49 | { |
| 50 | u32 sum = (__force u32)csum; |
| 51 | sum = (sum & 0xffff) + (sum >> 16); |
| 52 | sum = (sum & 0xffff) + (sum >> 16); |
| 53 | return (__force __sum16)~sum; |
| 54 | } |
| 55 | |
| 56 | #ifndef csum_tcpudp_nofold |
| 57 | /* |
| 58 | * computes the checksum of the TCP/UDP pseudo-header |
| 59 | * returns a 16-bit checksum, already complemented |
| 60 | */ |
| 61 | extern __wsum |
| 62 | csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, |
| 63 | unsigned short proto, __wsum sum); |
| 64 | #endif |
| 65 | |
| 66 | static inline __sum16 |
| 67 | csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len, |
| 68 | unsigned short proto, __wsum sum) |
| 69 | { |
| 70 | return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); |
| 71 | } |
| 72 | |
| 73 | /* |
| 74 | * this routine is used for miscellaneous IP-like checksums, mainly |
| 75 | * in icmp.c |
| 76 | */ |
| 77 | extern __sum16 ip_compute_csum(const void *buff, int len); |
| 78 | |
| 79 | #endif /* __ASM_GENERIC_CHECKSUM_H */ |