1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_CHECKSUM_64_H
3 #define _ASM_X86_CHECKSUM_64_H
7 * Copyright 2002 by Andi Kleen, SuSE Labs
8 * with some code from asm-x86/checksum.h
11 #include <linux/compiler.h>
12 #include <linux/uaccess.h>
13 #include <asm/byteorder.h>
16 * csum_fold - Fold and invert a 32bit checksum.
17 * sum: 32bit unfolded sum
19 * Fold a 32bit running checksum to 16bit and invert it. This is usually
20 * the last step before putting a checksum into a packet.
21 * Make sure not to mix with 64bit checksums.
23 static inline __sum16 csum_fold(__wsum sum)
28 : "r" ((__force u32)sum << 16),
29 "0" ((__force u32)sum & 0xffff0000));
30 return (__force __sum16)(~(__force u32)sum >> 16);
34 * This is a version of ip_compute_csum() optimized for IP headers,
35 * which always checksum on 4 octet boundaries.
37 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
42 * ip_fast_csum - Compute the IPv4 header checksum efficiently.
44 * ihl: length of header / 4
46 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
50 asm(" movl (%1), %0\n"
56 "1: adcl 16(%1), %0\n"
67 /* Since the input registers which are loaded with iph and ihl
68 are modified, we must also specify them as outputs, or gcc
69 will assume they contain their original values. */
70 : "=r" (sum), "=r" (iph), "=r" (ihl)
71 : "1" (iph), "2" (ihl)
73 return (__force __sum16)sum;
77 * csum_tcpup_nofold - Compute an IPv4 pseudo header checksum.
78 * @saddr: source address
79 * @daddr: destination address
80 * @len: length of packet
81 * @proto: ip protocol of packet
82 * @sum: initial sum to be added in (32bit unfolded)
84 * Returns the pseudo header checksum the input data. Result is
88 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
89 __u8 proto, __wsum sum)
96 : "g" (daddr), "g" (saddr),
97 "g" ((len + proto)<<8), "0" (sum));
103 * csum_tcpup_magic - Compute an IPv4 pseudo header checksum.
104 * @saddr: source address
105 * @daddr: destination address
106 * @len: length of packet
107 * @proto: ip protocol of packet
108 * @sum: initial sum to be added in (32bit unfolded)
110 * Returns the 16bit pseudo header checksum the input data already
111 * complemented and ready to be filled in.
113 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
114 __u32 len, __u8 proto,
117 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
121 * csum_partial - Compute an internet checksum.
122 * @buff: buffer to be checksummed
123 * @len: length of buffer.
124 * @sum: initial sum to be added in (32bit unfolded)
126 * Returns the 32bit unfolded internet checksum of the buffer.
127 * Before filling it in it needs to be csum_fold()'ed.
128 * buff should be aligned to a 64bit boundary if possible.
130 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
132 /* Do not call this directly. Use the wrappers below */
133 extern __visible __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
135 extern __wsum csum_and_copy_from_user(const void __user *src, void *dst, int len);
136 extern __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len);
137 extern __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len);
140 * ip_compute_csum - Compute an 16bit IP checksum.
141 * @buff: buffer address.
142 * @len: length of buffer.
144 * Returns the 16bit folded/inverted checksum of the passed buffer.
147 extern __sum16 ip_compute_csum(const void *buff, int len);
150 * csum_ipv6_magic - Compute checksum of an IPv6 pseudo header.
151 * @saddr: source address
152 * @daddr: destination address
153 * @len: length of packet
154 * @proto: protocol of packet
155 * @sum: initial sum (32bit unfolded) to be added in
157 * Computes an IPv6 pseudo header checksum. This sum is added the checksum
158 * into UDP/TCP packets and contains some link layer information.
159 * Returns the unfolded 32bit checksum.
164 #define _HAVE_ARCH_IPV6_CSUM 1
166 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
167 __u32 len, __u8 proto, __wsum sum);
169 static inline unsigned add32_with_carry(unsigned a, unsigned b)
174 : "0" (a), "rm" (b));
178 #define HAVE_ARCH_CSUM_ADD
179 static inline __wsum csum_add(__wsum csum, __wsum addend)
181 return (__force __wsum)add32_with_carry((__force unsigned)csum,
182 (__force unsigned)addend);
185 #endif /* _ASM_X86_CHECKSUM_64_H */