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author | Arnd Bergmann <arnd@arndb.de> | 2009-05-13 22:56:38 +0000 |
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committer | Arnd Bergmann <arnd@klappe2.(none)> | 2009-06-11 21:02:51 +0200 |
commit | 26a28fa4fea5b8c65713aa50c124f76a88c7924d (patch) | |
tree | 95d5989e0cdcb4f565d7546b4c0fd76e30cfd249 /include/asm-generic/checksum.h | |
parent | eed417ddd52146f446595b5a7d8f21b1814b95b7 (diff) | |
download | kernel_samsung_crespo-26a28fa4fea5b8c65713aa50c124f76a88c7924d.zip kernel_samsung_crespo-26a28fa4fea5b8c65713aa50c124f76a88c7924d.tar.gz kernel_samsung_crespo-26a28fa4fea5b8c65713aa50c124f76a88c7924d.tar.bz2 |
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 <monstr@monstr.eu>
Cc: Michal Simek <monstr@monstr.eu>
Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'include/asm-generic/checksum.h')
-rw-r--r-- | include/asm-generic/checksum.h | 79 |
1 files changed, 79 insertions, 0 deletions
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 */ |