2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * Copyright (C) 1995, 1996, 1997, 1998, 2001 by Ralf Baechle
8 #ifndef _ASM_CHECKSUM_H
9 #define _ASM_CHECKSUM_H
11 #include <asm/uaccess.h>
14 * computes the checksum of a memory block at buff, length len,
15 * and adds in "sum" (32-bit)
17 * returns a 32-bit number suitable for feeding into itself
18 * or csum_tcpudp_magic
20 * this function must be called with even lengths, except
21 * for the last fragment, which may be odd
23 * it's best to have buff aligned on a 32-bit boundary
25 unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);
28 * this is a new version of the above that records errors it finds in *errp,
29 * but continues and zeros the rest of the buffer.
31 #define csum_partial_copy_nocheck csum_partial_copy
34 * this is a new version of the above that records errors it finds in *errp,
35 * but continues and zeros the rest of the buffer.
37 unsigned int csum_partial_copy_from_user(const char *src, char *dst, int len,
38 unsigned int sum, int *errp);
41 * Copy and checksum to user
43 #define HAVE_CSUM_COPY_USER
44 static inline unsigned int csum_and_copy_to_user (const char *src, char *dst,
48 sum = csum_partial(src, len, sum);
50 if (copy_to_user(dst, src, len)) {
59 * the same as csum_partial, but copies from user space (but on MIPS
60 * we have just one address space, so this is identical to the above)
62 * this is obsolete and will go away.
64 #define csum_partial_copy_fromuser csum_partial_copy
65 unsigned int csum_partial_copy(const char *src, char *dst, int len,
69 * Fold a partial checksum without adding pseudo headers
71 static inline unsigned short int csum_fold(unsigned int sum)
74 ".set\tnoat\t\t\t# csum_fold\n\t"
89 * This is a version of ip_compute_csum() optimized for IP headers,
90 * which always checksum on 4 octet boundaries.
92 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
95 static inline unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl)
97 unsigned int *word = (unsigned int *) iph;
98 unsigned int *stop = word + ihl;
104 carry = (csum < word[1]);
108 carry = (csum < word[2]);
112 carry = (csum < word[3]);
118 carry = (csum < *word);
121 } while (word != stop);
123 return csum_fold(csum);
126 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
129 unsigned short proto,
133 ".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
135 "sltu\t$1, %0, %2\n\t"
139 "sltu\t$1, %0, %3\n\t"
143 "sltu\t$1, %0, %4\n\t"
147 : "0" (daddr), "r"(saddr),
149 "r" ((ntohs(len)<<16)+proto*256),
151 "r" (((proto)<<16)+len),
159 * computes the checksum of the TCP/UDP pseudo-header
160 * returns a 16-bit checksum, already complemented
162 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
165 unsigned short proto,
168 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
172 * this routine is used for miscellaneous IP-like checksums, mainly
175 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
177 return csum_fold(csum_partial(buff, len, 0));
180 #define _HAVE_ARCH_IPV6_CSUM
181 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
182 struct in6_addr *daddr,
184 unsigned short proto,
188 ".set\tpush\t\t\t# csum_ipv6_magic\n\t"
189 ".set\tnoreorder\n\t"
191 "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
192 "sltu\t$1, %0, %5\n\t"
195 "addu\t%0, %6\t\t\t# csum\n\t"
196 "sltu\t$1, %0, %6\n\t"
197 "lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
200 "sltu\t$1, %0, %1\n\t"
205 "sltu\t$1, %0, %1\n\t"
210 "sltu\t$1, %0, %1\n\t"
215 "sltu\t$1, %0, %1\n\t"
220 "sltu\t$1, %0, %1\n\t"
225 "sltu\t$1, %0, %1\n\t"
230 "sltu\t$1, %0, %1\n\t"
235 "sltu\t$1, %0, %1\n\t"
237 "addu\t%0, $1\t\t\t# Add final carry\n\t"
239 : "=r" (sum), "=r" (proto)
240 : "r" (saddr), "r" (daddr),
241 "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
243 return csum_fold(sum);
246 #endif /* _ASM_CHECKSUM_H */