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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-cris/checksum.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-cris/checksum.h')
-rw-r--r-- | include/asm-cris/checksum.h | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/include/asm-cris/checksum.h b/include/asm-cris/checksum.h new file mode 100644 index 000000000000..15ca8aec5c63 --- /dev/null +++ b/include/asm-cris/checksum.h @@ -0,0 +1,87 @@ +/* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */ + +#ifndef _CRIS_CHECKSUM_H +#define _CRIS_CHECKSUM_H + +#include <asm/arch/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 + */ +unsigned int csum_partial(const unsigned char * buff, int len, unsigned int 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 + */ + +unsigned int csum_partial_copy_nocheck(const char *src, char *dst, + int len, unsigned int sum); + +/* + * Fold a partial checksum into a word + */ + +extern inline unsigned int csum_fold(unsigned int sum) +{ + /* the while loop is unnecessary really, it's always enough with two + iterations */ + + while(sum >> 16) + sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */ + + return ~sum; +} + +extern unsigned int csum_partial_copy_from_user(const char *src, char *dst, + int len, unsigned int sum, + int *errptr); + +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + * + */ + +extern inline unsigned short ip_fast_csum(unsigned char * iph, + unsigned int ihl) +{ + return csum_fold(csum_partial(iph, ihl * 4, 0)); +} + +/* + * computes the checksum of the TCP/UDP pseudo-header + * returns a 16-bit checksum, already complemented + */ + +extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr, + unsigned long daddr, + unsigned short len, + unsigned short proto, + unsigned int 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 inline unsigned short ip_compute_csum(unsigned char * buff, int len) { + return csum_fold (csum_partial(buff, len, 0)); +} + +#endif |