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.
6 * Checksumming functions for IP, TCP, UDP and so on
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.
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.
22 * Ralf Baechle : generic ipv6 checksum
23 * <ralf@waldorf-gmbh.de>
29 #include <asm/types.h>
30 #include <asm/byteorder.h>
32 #include <linux/in6.h>
33 #include <asm/uaccess.h>
34 #include <asm/checksum.h>
36 #ifndef _HAVE_ARCH_IPV6_CSUM
38 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
39 struct in6_addr *daddr,
49 csum += saddr->s6_addr32[0];
50 carry = (csum < saddr->s6_addr32[0]);
53 csum += saddr->s6_addr32[1];
54 carry = (csum < saddr->s6_addr32[1]);
57 csum += saddr->s6_addr32[2];
58 carry = (csum < saddr->s6_addr32[2]);
61 csum += saddr->s6_addr32[3];
62 carry = (csum < saddr->s6_addr32[3]);
65 csum += daddr->s6_addr32[0];
66 carry = (csum < daddr->s6_addr32[0]);
69 csum += daddr->s6_addr32[1];
70 carry = (csum < daddr->s6_addr32[1]);
73 csum += daddr->s6_addr32[2];
74 carry = (csum < daddr->s6_addr32[2]);
77 csum += daddr->s6_addr32[3];
78 carry = (csum < daddr->s6_addr32[3]);
81 ulen = htonl((__u32) len);
83 carry = (csum < ulen);
86 uproto = htonl(proto);
88 carry = (csum < uproto);
91 return csum_fold(csum);
96 #ifndef _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
98 unsigned int csum_and_copy_from_user (const char *src, char *dst,
99 int len, int sum, int *err_ptr)
101 if (verify_area(VERIFY_READ, src, len) == 0)
102 return csum_partial_copy_from_user(src, dst, len, sum, err_ptr);
111 #ifndef HAVE_CSUM_COPY_USER
112 static __inline__ unsigned int csum_and_copy_to_user
113 (const char *src, char *dst, int len, unsigned int sum, int *err_ptr)
115 sum = csum_partial(src, len, sum);
117 if (access_ok(VERIFY_WRITE, dst, len)) {
118 if (copy_to_user(dst, src, len) == 0)
124 return -1; /* invalid checksum */
128 static inline unsigned int csum_add(unsigned int csum, unsigned int addend)
131 return csum + (csum < addend);
134 static inline unsigned int csum_sub(unsigned int csum, unsigned int addend)
136 return csum_add(csum, ~addend);
139 static inline unsigned int
140 csum_block_add(unsigned int csum, unsigned int csum2, int offset)
143 csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
144 return csum_add(csum, csum2);
147 static inline unsigned int
148 csum_block_sub(unsigned int csum, unsigned int csum2, int offset)
151 csum2 = ((csum2&0xFF00FF)<<8)+((csum2>>8)&0xFF00FF);
152 return csum_sub(csum, csum2);