1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef __UM_CHECKSUM_H
3*4882a593Smuzhiyun #define __UM_CHECKSUM_H
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun #include <linux/string.h>
6*4882a593Smuzhiyun #include <linux/in6.h>
7*4882a593Smuzhiyun #include <linux/uaccess.h>
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun /*
10*4882a593Smuzhiyun * computes the checksum of a memory block at buff, length len,
11*4882a593Smuzhiyun * and adds in "sum" (32-bit)
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun * returns a 32-bit number suitable for feeding into itself
14*4882a593Smuzhiyun * or csum_tcpudp_magic
15*4882a593Smuzhiyun *
16*4882a593Smuzhiyun * this function must be called with even lengths, except
17*4882a593Smuzhiyun * for the last fragment, which may be odd
18*4882a593Smuzhiyun *
19*4882a593Smuzhiyun * it's best to have buff aligned on a 32-bit boundary
20*4882a593Smuzhiyun */
21*4882a593Smuzhiyun extern __wsum csum_partial(const void *buff, int len, __wsum sum);
22*4882a593Smuzhiyun
23*4882a593Smuzhiyun /**
24*4882a593Smuzhiyun * csum_fold - Fold and invert a 32bit checksum.
25*4882a593Smuzhiyun * sum: 32bit unfolded sum
26*4882a593Smuzhiyun *
27*4882a593Smuzhiyun * Fold a 32bit running checksum to 16bit and invert it. This is usually
28*4882a593Smuzhiyun * the last step before putting a checksum into a packet.
29*4882a593Smuzhiyun * Make sure not to mix with 64bit checksums.
30*4882a593Smuzhiyun */
csum_fold(__wsum sum)31*4882a593Smuzhiyun static inline __sum16 csum_fold(__wsum sum)
32*4882a593Smuzhiyun {
33*4882a593Smuzhiyun __asm__(
34*4882a593Smuzhiyun " addl %1,%0\n"
35*4882a593Smuzhiyun " adcl $0xffff,%0"
36*4882a593Smuzhiyun : "=r" (sum)
37*4882a593Smuzhiyun : "r" ((__force u32)sum << 16),
38*4882a593Smuzhiyun "0" ((__force u32)sum & 0xffff0000)
39*4882a593Smuzhiyun );
40*4882a593Smuzhiyun return (__force __sum16)(~(__force u32)sum >> 16);
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun /**
44*4882a593Smuzhiyun * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
45*4882a593Smuzhiyun * @saddr: source address
46*4882a593Smuzhiyun * @daddr: destination address
47*4882a593Smuzhiyun * @len: length of packet
48*4882a593Smuzhiyun * @proto: ip protocol of packet
49*4882a593Smuzhiyun * @sum: initial sum to be added in (32bit unfolded)
50*4882a593Smuzhiyun *
51*4882a593Smuzhiyun * Returns the pseudo header checksum the input data. Result is
52*4882a593Smuzhiyun * 32bit unfolded.
53*4882a593Smuzhiyun */
54*4882a593Smuzhiyun static inline __wsum
csum_tcpudp_nofold(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)55*4882a593Smuzhiyun csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
56*4882a593Smuzhiyun __u8 proto, __wsum sum)
57*4882a593Smuzhiyun {
58*4882a593Smuzhiyun asm(" addl %1, %0\n"
59*4882a593Smuzhiyun " adcl %2, %0\n"
60*4882a593Smuzhiyun " adcl %3, %0\n"
61*4882a593Smuzhiyun " adcl $0, %0\n"
62*4882a593Smuzhiyun : "=r" (sum)
63*4882a593Smuzhiyun : "g" (daddr), "g" (saddr), "g" ((len + proto) << 8), "0" (sum));
64*4882a593Smuzhiyun return sum;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun /*
68*4882a593Smuzhiyun * computes the checksum of the TCP/UDP pseudo-header
69*4882a593Smuzhiyun * returns a 16-bit checksum, already complemented
70*4882a593Smuzhiyun */
csum_tcpudp_magic(__be32 saddr,__be32 daddr,__u32 len,__u8 proto,__wsum sum)71*4882a593Smuzhiyun static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
72*4882a593Smuzhiyun __u32 len, __u8 proto,
73*4882a593Smuzhiyun __wsum sum)
74*4882a593Smuzhiyun {
75*4882a593Smuzhiyun return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun /**
79*4882a593Smuzhiyun * ip_fast_csum - Compute the IPv4 header checksum efficiently.
80*4882a593Smuzhiyun * iph: ipv4 header
81*4882a593Smuzhiyun * ihl: length of header / 4
82*4882a593Smuzhiyun */
ip_fast_csum(const void * iph,unsigned int ihl)83*4882a593Smuzhiyun static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
84*4882a593Smuzhiyun {
85*4882a593Smuzhiyun unsigned int sum;
86*4882a593Smuzhiyun
87*4882a593Smuzhiyun asm( " movl (%1), %0\n"
88*4882a593Smuzhiyun " subl $4, %2\n"
89*4882a593Smuzhiyun " jbe 2f\n"
90*4882a593Smuzhiyun " addl 4(%1), %0\n"
91*4882a593Smuzhiyun " adcl 8(%1), %0\n"
92*4882a593Smuzhiyun " adcl 12(%1), %0\n"
93*4882a593Smuzhiyun "1: adcl 16(%1), %0\n"
94*4882a593Smuzhiyun " lea 4(%1), %1\n"
95*4882a593Smuzhiyun " decl %2\n"
96*4882a593Smuzhiyun " jne 1b\n"
97*4882a593Smuzhiyun " adcl $0, %0\n"
98*4882a593Smuzhiyun " movl %0, %2\n"
99*4882a593Smuzhiyun " shrl $16, %0\n"
100*4882a593Smuzhiyun " addw %w2, %w0\n"
101*4882a593Smuzhiyun " adcl $0, %0\n"
102*4882a593Smuzhiyun " notl %0\n"
103*4882a593Smuzhiyun "2:"
104*4882a593Smuzhiyun /* Since the input registers which are loaded with iph and ipl
105*4882a593Smuzhiyun are modified, we must also specify them as outputs, or gcc
106*4882a593Smuzhiyun will assume they contain their original values. */
107*4882a593Smuzhiyun : "=r" (sum), "=r" (iph), "=r" (ihl)
108*4882a593Smuzhiyun : "1" (iph), "2" (ihl)
109*4882a593Smuzhiyun : "memory");
110*4882a593Smuzhiyun return (__force __sum16)sum;
111*4882a593Smuzhiyun }
112*4882a593Smuzhiyun
113*4882a593Smuzhiyun #ifdef CONFIG_X86_32
114*4882a593Smuzhiyun # include "checksum_32.h"
115*4882a593Smuzhiyun #else
116*4882a593Smuzhiyun # include "checksum_64.h"
117*4882a593Smuzhiyun #endif
118*4882a593Smuzhiyun
119*4882a593Smuzhiyun #endif
120