From 26a28fa4fea5b8c65713aa50c124f76a88c7924d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 13 May 2009 22:56:38 +0000 Subject: add generic lib/checksum.c Add a generic (unoptimized) implementation of checksum.c in pure C for use by all architectures that cannot be bother with implementing their own version. Based on microblaze code by Michal Simek Cc: Michal Simek Signed-off-by: Remis Lima Baima Signed-off-by: Arnd Bergmann --- include/asm-generic/checksum.h | 79 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100644 include/asm-generic/checksum.h (limited to 'include/asm-generic') diff --git a/include/asm-generic/checksum.h b/include/asm-generic/checksum.h new file mode 100644 index 0000000..4647c76 --- /dev/null +++ b/include/asm-generic/checksum.h @@ -0,0 +1,79 @@ +#ifndef __ASM_GENERIC_CHECKSUM_H +#define __ASM_GENERIC_CHECKSUM_H + +/* + * computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * this function must be called with even lengths, except + * for the last fragment, which may be odd + * + * it's best to have buff aligned on a 32-bit boundary + */ +extern __wsum csum_partial(const void *buff, int len, __wsum sum); + +/* + * the same as csum_partial, but copies from src while it + * checksums + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ +extern __wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum); + +/* + * the same as csum_partial_copy, but copies from user space. + * + * here even more important to align src and dst on a 32-bit (or even + * better 64-bit) boundary + */ +extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst, + int len, __wsum sum, int *csum_err); + +#define csum_partial_copy_nocheck(src, dst, len, sum) \ + csum_partial_copy((src), (dst), (len), (sum)) + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + */ +extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); + +/* + * Fold a partial checksum + */ +static inline __sum16 csum_fold(__wsum csum) +{ + u32 sum = (__force u32)csum; + sum = (sum & 0xffff) + (sum >> 16); + sum = (sum & 0xffff) + (sum >> 16); + return (__force __sum16)~sum; +} + +#ifndef csum_tcpudp_nofold +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ +extern __wsum +csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len, + unsigned short proto, __wsum sum); +#endif + +static inline __sum16 +csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len, + unsigned short proto, __wsum sum) +{ + return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum)); +} + +/* + * this routine is used for miscellaneous IP-like checksums, mainly + * in icmp.c + */ +extern __sum16 ip_compute_csum(const void *buff, int len); + +#endif /* __ASM_GENERIC_CHECKSUM_H */ -- cgit v1.1