xref: /openbmc/linux/include/net/ip6_checksum.h (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		Checksumming functions for IPv6
7  *
8  * Authors:	Jorge Cwik, <jorge@laser.satlink.net>
9  *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
10  *		Borrows very liberally from tcp.c and ip.c, see those
11  *		files for more names.
12  *
13  *		This program is free software; you can redistribute it and/or
14  *		modify it under the terms of the GNU General Public License
15  *		as published by the Free Software Foundation; either version
16  *		2 of the License, or (at your option) any later version.
17  */
18 
19 /*
20  *	Fixes:
21  *
22  *	Ralf Baechle			:	generic ipv6 checksum
23  *	<ralf@waldorf-gmbh.de>
24  */
25 
26 #ifndef _CHECKSUM_IPV6_H
27 #define _CHECKSUM_IPV6_H
28 
29 #include <asm/types.h>
30 #include <asm/byteorder.h>
31 #include <net/ip.h>
32 #include <asm/checksum.h>
33 #include <linux/in6.h>
34 
35 #ifndef _HAVE_ARCH_IPV6_CSUM
36 
37 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
38 						     struct in6_addr *daddr,
39 						     __u16 len,
40 						     unsigned short proto,
41 						     unsigned int csum)
42 {
43 
44 	int carry;
45 	__u32 ulen;
46 	__u32 uproto;
47 
48 	csum += saddr->s6_addr32[0];
49 	carry = (csum < saddr->s6_addr32[0]);
50 	csum += carry;
51 
52 	csum += saddr->s6_addr32[1];
53 	carry = (csum < saddr->s6_addr32[1]);
54 	csum += carry;
55 
56 	csum += saddr->s6_addr32[2];
57 	carry = (csum < saddr->s6_addr32[2]);
58 	csum += carry;
59 
60 	csum += saddr->s6_addr32[3];
61 	carry = (csum < saddr->s6_addr32[3]);
62 	csum += carry;
63 
64 	csum += daddr->s6_addr32[0];
65 	carry = (csum < daddr->s6_addr32[0]);
66 	csum += carry;
67 
68 	csum += daddr->s6_addr32[1];
69 	carry = (csum < daddr->s6_addr32[1]);
70 	csum += carry;
71 
72 	csum += daddr->s6_addr32[2];
73 	carry = (csum < daddr->s6_addr32[2]);
74 	csum += carry;
75 
76 	csum += daddr->s6_addr32[3];
77 	carry = (csum < daddr->s6_addr32[3]);
78 	csum += carry;
79 
80 	ulen = htonl((__u32) len);
81 	csum += ulen;
82 	carry = (csum < ulen);
83 	csum += carry;
84 
85 	uproto = htonl(proto);
86 	csum += uproto;
87 	carry = (csum < uproto);
88 	csum += carry;
89 
90 	return csum_fold(csum);
91 }
92 
93 #endif
94 #endif
95