arch/cris/include/asm/checksum.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
   3
   4 #ifndef _CRIS_CHECKSUM_H
   5 #define _CRIS_CHECKSUM_H
   6
   7 #include <arch/checksum.h>
   8
   9 /*
  10  * computes the checksum of a memory block at buff, length len,
  11  * and adds in "sum" (32-bit)
  12  *
  13  * returns a 32-bit number suitable for feeding into itself
  14  * or csum_tcpudp_magic
  15  *
  16  * this function must be called with even lengths, except
  17  * for the last fragment, which may be odd
  18  *
  19  * it's best to have buff aligned on a 32-bit boundary
  20  */
  21 __wsum csum_partial(const void *buff, int len, __wsum sum);
  22
  23 /*
  24  * the same as csum_partial, but copies from src while it
  25  * checksums
  26  *
  27  * here even more important to align src and dst on a 32-bit (or even
  28  * better 64-bit) boundary
  29  */
  30
  31 __wsum csum_partial_copy_nocheck(const void *src, void *dst,
  32                                        int len, __wsum sum);
  33
  34 /*
  35  *      Fold a partial checksum into a word
  36  */
  37
  38 static inline __sum16 csum_fold(__wsum csum)
  39 {
  40         u32 sum = (__force u32)csum;
  41         sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
  42         sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
  43         return (__force __sum16)~sum;
  44 }
  45
  46 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  47                                                 int len, __wsum sum,
  48                                                 int *errptr);
  49
  50 /*
  51  *      This is a version of ip_compute_csum() optimized for IP headers,
  52  *      which always checksum on 4 octet boundaries.
  53  *
  54  */
  55
  56 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  57 {
  58         return csum_fold(csum_partial(iph, ihl * 4, 0));
  59 }
  60
  61 /*
  62  * computes the checksum of the TCP/UDP pseudo-header
  63  * returns a 16-bit checksum, already complemented
  64  */
  65
  66 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  67                                         __u32 len, __u8 proto,
  68                                         __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
  78 static inline __sum16 ip_compute_csum(const void *buff, int len)
  79 {
  80         return csum_fold (csum_partial(buff, len, 0));
  81 }
  82
  83 #endif