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/* SPDX-License-Identifier: GPL-2.0 */
/*
* S390 fast network checksum routines
*
* S390 version
* Copyright IBM Corp. 1999
* Author(s): Ulrich Hild (first version)
* Martin Schwidefsky (heavily optimized CKSM version)
* D.J. Barrow (third attempt)
*/
#ifndef _S390_CHECKSUM_H
#define _S390_CHECKSUM_H
#include <linux/uaccess.h>
#include <linux/in6.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.
*/
static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
{
union register_pair rp = {
.even = (unsigned long) buff,
.odd = (unsigned long) len,
};
asm volatile(
"0: cksm %[sum],%[rp]\n"
" jo 0b\n"
: [sum] "+&d" (sum), [rp] "+&d" (rp.pair) : : "cc", "memory");
return sum;
}
/*
* Fold a partial checksum without adding pseudo headers.
*/
static inline __sum16 csum_fold(__wsum sum)
{
u32 csum = (__force u32) sum;
csum += (csum >> 16) | (csum << 16);
csum >>= 16;
return (__force __sum16) ~csum;
}
/*
* This is a version of ip_compute_csum() optimized for IP headers,
* which always checksums on 4 octet boundaries.
*/
static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
{
__u64 csum = 0;
__u32 *ptr = (u32 *)iph;
csum += *ptr++;
csum += *ptr++;
csum += *ptr++;
csum += *ptr++;
ihl -= 4;
while (ihl--)
csum += *ptr++;
csum += (csum >> 32) | (csum << 32);
return csum_fold((__force __wsum)(csum >> 32));
}
/*
* Computes the checksum of the TCP/UDP pseudo-header.
* Returns a 32-bit checksum.
*/
static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
__u8 proto, __wsum sum)
{
__u64 csum = (__force __u64)sum;
csum += (__force __u32)saddr;
csum += (__force __u32)daddr;
csum += len;
csum += proto;
csum += (csum >> 32) | (csum << 32);
return (__force __wsum)(csum >> 32);
}
/*
* Computes the checksum of the TCP/UDP pseudo-header.
* Returns a 16-bit checksum, already complemented.
*/
static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
__u8 proto, __wsum sum)
{
return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
}
/*
* Used for miscellaneous IP-like checksums, mainly icmp.
*/
static inline __sum16 ip_compute_csum(const void *buff, int len)
{
return csum_fold(csum_partial(buff, len, 0));
}
#define _HAVE_ARCH_IPV6_CSUM
static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
const struct in6_addr *daddr,
__u32 len, __u8 proto, __wsum csum)
{
__u64 sum = (__force __u64)csum;
sum += (__force __u32)saddr->s6_addr32[0];
sum += (__force __u32)saddr->s6_addr32[1];
sum += (__force __u32)saddr->s6_addr32[2];
sum += (__force __u32)saddr->s6_addr32[3];
sum += (__force __u32)daddr->s6_addr32[0];
sum += (__force __u32)daddr->s6_addr32[1];
sum += (__force __u32)daddr->s6_addr32[2];
sum += (__force __u32)daddr->s6_addr32[3];
sum += len;
sum += proto;
sum += (sum >> 32) | (sum << 32);
return csum_fold((__force __wsum)(sum >> 32));
}
#endif /* _S390_CHECKSUM_H */
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