root/arch/alpha/include/asm/checksum.h

INCLUDED FROM

DEFINITIONS

1. csum_fold

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ALPHA_CHECKSUM_H
   3 #define _ALPHA_CHECKSUM_H
   4 
   5 #include <linux/in6.h>
   6 
   7 /*
   8  *      This is a version of ip_compute_csum() optimized for IP headers,
   9  *      which always checksum on 4 octet boundaries.
  10  */
  11 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  12 
  13 /*
  14  * computes the checksum of the TCP/UDP pseudo-header
  15  * returns a 16-bit checksum, already complemented
  16  */
  17 __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  18                           __u32 len, __u8 proto, __wsum sum);
  19 
  20 __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  21                           __u32 len, __u8 proto, __wsum sum);
  22 
  23 /*
  24  * computes the checksum of a memory block at buff, length len,
  25  * and adds in "sum" (32-bit)
  26  *
  27  * returns a 32-bit number suitable for feeding into itself
  28  * or csum_tcpudp_magic
  29  *
  30  * this function must be called with even lengths, except
  31  * for the last fragment, which may be odd
  32  *
  33  * it's best to have buff aligned on a 32-bit boundary
  34  */
  35 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  36 
  37 /*
  38  * the same as csum_partial, but copies from src while it
  39  * checksums
  40  *
  41  * here even more important to align src and dst on a 32-bit (or even
  42  * better 64-bit) boundary
  43  */
  44 __wsum csum_partial_copy_from_user(const void __user *src, void *dst, int len, __wsum sum, int *errp);
  45 
  46 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
  47 
  48 
  49 /*
  50  * this routine is used for miscellaneous IP-like checksums, mainly
  51  * in icmp.c
  52  */
  53 
  54 extern __sum16 ip_compute_csum(const void *buff, int len);
  55 
  56 /*
  57  *      Fold a partial checksum without adding pseudo headers
  58  */
  59 
  60 static inline __sum16 csum_fold(__wsum csum)
  61 {
  62         u32 sum = (__force u32)csum;
  63         sum = (sum & 0xffff) + (sum >> 16);
  64         sum = (sum & 0xffff) + (sum >> 16);
  65         return (__force __sum16)~sum;
  66 }
  67 
  68 #define _HAVE_ARCH_IPV6_CSUM
  69 extern __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
  70                                const struct in6_addr *daddr,
  71                                __u32 len, __u8 proto, __wsum sum);
  72 #endif