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