1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * S390 fast network checksum routines
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * S390 version
6*4882a593Smuzhiyun * Copyright IBM Corp. 1999
7*4882a593Smuzhiyun * Author(s): Ulrich Hild (first version)
8*4882a593Smuzhiyun * Martin Schwidefsky (heavily optimized CKSM version)
9*4882a593Smuzhiyun * D.J. Barrow (third attempt)
10*4882a593Smuzhiyun */
11*4882a593Smuzhiyun
12*4882a593Smuzhiyun #ifndef _S390_CHECKSUM_H
13*4882a593Smuzhiyun #define _S390_CHECKSUM_H
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <linux/uaccess.h>
16*4882a593Smuzhiyun #include <linux/in6.h>
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun /*
19*4882a593Smuzhiyun * Computes the checksum of a memory block at buff, length len,
20*4882a593Smuzhiyun * and adds in "sum" (32-bit).
21*4882a593Smuzhiyun *
22*4882a593Smuzhiyun * Returns a 32-bit number suitable for feeding into itself
23*4882a593Smuzhiyun * or csum_tcpudp_magic.
24*4882a593Smuzhiyun *
25*4882a593Smuzhiyun * This function must be called with even lengths, except
26*4882a593Smuzhiyun * for the last fragment, which may be odd.
27*4882a593Smuzhiyun *
28*4882a593Smuzhiyun * It's best to have buff aligned on a 32-bit boundary.
29*4882a593Smuzhiyun */
csum_partial(const void * buff,int len,__wsum sum)30*4882a593Smuzhiyun static inline __wsum csum_partial(const void *buff, int len, __wsum sum)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun register unsigned long reg2 asm("2") = (unsigned long) buff;
33*4882a593Smuzhiyun register unsigned long reg3 asm("3") = (unsigned long) len;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun asm volatile(
36*4882a593Smuzhiyun "0: cksm %0,%1\n" /* do checksum on longs */
37*4882a593Smuzhiyun " jo 0b\n"
38*4882a593Smuzhiyun : "+d" (sum), "+d" (reg2), "+d" (reg3) : : "cc", "memory");
39*4882a593Smuzhiyun return sum;
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun /*
43*4882a593Smuzhiyun * Fold a partial checksum without adding pseudo headers.
44*4882a593Smuzhiyun */
csum_fold(__wsum sum)45*4882a593Smuzhiyun static inline __sum16 csum_fold(__wsum sum)
46*4882a593Smuzhiyun {
47*4882a593Smuzhiyun u32 csum = (__force u32) sum;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun csum += (csum >> 16) | (csum << 16);
50*4882a593Smuzhiyun csum >>= 16;
51*4882a593Smuzhiyun return (__force __sum16) ~csum;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun /*
55*4882a593Smuzhiyun * This is a version of ip_compute_csum() optimized for IP headers,
56*4882a593Smuzhiyun * which always checksums on 4 octet boundaries.
57*4882a593Smuzhiyun */
ip_fast_csum(const void * iph,unsigned int ihl)58*4882a593Smuzhiyun static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
59*4882a593Smuzhiyun {
60*4882a593Smuzhiyun __u64 csum = 0;
61*4882a593Smuzhiyun __u32 *ptr = (u32 *)iph;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun csum += *ptr++;
64*4882a593Smuzhiyun csum += *ptr++;
65*4882a593Smuzhiyun csum += *ptr++;
66*4882a593Smuzhiyun csum += *ptr++;
67*4882a593Smuzhiyun ihl -= 4;
68*4882a593Smuzhiyun while (ihl--)
69*4882a593Smuzhiyun csum += *ptr++;
70*4882a593Smuzhiyun csum += (csum >> 32) | (csum << 32);
71*4882a593Smuzhiyun return csum_fold((__force __wsum)(csum >> 32));
72*4882a593Smuzhiyun }
73*4882a593Smuzhiyun
74*4882a593Smuzhiyun /*
75*4882a593Smuzhiyun * Computes the checksum of the TCP/UDP pseudo-header.
76*4882a593Smuzhiyun * Returns a 32-bit checksum.
77*4882a593Smuzhiyun */
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)78*4882a593Smuzhiyun static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
79*4882a593Smuzhiyun __u8 proto, __wsum sum)
80*4882a593Smuzhiyun {
81*4882a593Smuzhiyun __u64 csum = (__force __u64)sum;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun csum += (__force __u32)saddr;
84*4882a593Smuzhiyun csum += (__force __u32)daddr;
85*4882a593Smuzhiyun csum += len;
86*4882a593Smuzhiyun csum += proto;
87*4882a593Smuzhiyun csum += (csum >> 32) | (csum << 32);
88*4882a593Smuzhiyun return (__force __wsum)(csum >> 32);
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun
91*4882a593Smuzhiyun /*
92*4882a593Smuzhiyun * Computes the checksum of the TCP/UDP pseudo-header.
93*4882a593Smuzhiyun * Returns a 16-bit checksum, already complemented.
94*4882a593Smuzhiyun */
csum_tcpudp_magic(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)95*4882a593Smuzhiyun static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, __u32 len,
96*4882a593Smuzhiyun __u8 proto, __wsum sum)
97*4882a593Smuzhiyun {
98*4882a593Smuzhiyun return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
99*4882a593Smuzhiyun }
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun /*
102*4882a593Smuzhiyun * Used for miscellaneous IP-like checksums, mainly icmp.
103*4882a593Smuzhiyun */
ip_compute_csum(const void * buff,int len)104*4882a593Smuzhiyun static inline __sum16 ip_compute_csum(const void *buff, int len)
105*4882a593Smuzhiyun {
106*4882a593Smuzhiyun return csum_fold(csum_partial(buff, len, 0));
107*4882a593Smuzhiyun }
108*4882a593Smuzhiyun
109*4882a593Smuzhiyun #define _HAVE_ARCH_IPV6_CSUM
csum_ipv6_magic(const struct in6_addr * saddr,const struct in6_addr * daddr,__u32 len,__u8 proto,__wsum csum)110*4882a593Smuzhiyun static inline __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
111*4882a593Smuzhiyun const struct in6_addr *daddr,
112*4882a593Smuzhiyun __u32 len, __u8 proto, __wsum csum)
113*4882a593Smuzhiyun {
114*4882a593Smuzhiyun __u64 sum = (__force __u64)csum;
115*4882a593Smuzhiyun
116*4882a593Smuzhiyun sum += (__force __u32)saddr->s6_addr32[0];
117*4882a593Smuzhiyun sum += (__force __u32)saddr->s6_addr32[1];
118*4882a593Smuzhiyun sum += (__force __u32)saddr->s6_addr32[2];
119*4882a593Smuzhiyun sum += (__force __u32)saddr->s6_addr32[3];
120*4882a593Smuzhiyun sum += (__force __u32)daddr->s6_addr32[0];
121*4882a593Smuzhiyun sum += (__force __u32)daddr->s6_addr32[1];
122*4882a593Smuzhiyun sum += (__force __u32)daddr->s6_addr32[2];
123*4882a593Smuzhiyun sum += (__force __u32)daddr->s6_addr32[3];
124*4882a593Smuzhiyun sum += len;
125*4882a593Smuzhiyun sum += proto;
126*4882a593Smuzhiyun sum += (sum >> 32) | (sum << 32);
127*4882a593Smuzhiyun return csum_fold((__force __wsum)(sum >> 32));
128*4882a593Smuzhiyun }
129*4882a593Smuzhiyun
130*4882a593Smuzhiyun #endif /* _S390_CHECKSUM_H */
131