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, 1999 by Ralf Baechle
7 * Copyright (C) 1999 Silicon Graphics, Inc.
8 * Copyright (C) 2001 Thiemo Seufer.
9 * Copyright (C) 2002 Maciej W. Rozycki
11 #ifndef _ASM_CHECKSUM_H
12 #define _ASM_CHECKSUM_H
14 #include <asm/uaccess.h>
15 #include <linux/in6.h>
18 * computes the checksum of a memory block at buff, length len,
19 * and adds in "sum" (32-bit)
21 * returns a 32-bit number suitable for feeding into itself
22 * or csum_tcpudp_magic
24 * this function must be called with even lengths, except
25 * for the last fragment, which may be odd
27 * it's best to have buff aligned on a 32-bit boundary
29 unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum);
32 * this is a new version of the above that records errors it finds in *errp,
33 * but continues and zeros the rest of the buffer.
35 unsigned int csum_partial_copy_from_user(const char *src, char *dst, int len,
36 unsigned int sum, int *errp);
39 * Copy and checksum to user
41 #define HAVE_CSUM_COPY_USER
42 static inline unsigned int csum_and_copy_to_user (const char *src, char *dst,
46 sum = csum_partial(src, len, sum);
48 if (copy_to_user(dst, src, len)) {
57 * the same as csum_partial, but copies from user space (but on MIPS
58 * we have just one address space, so this is identical to the above)
60 unsigned int csum_partial_copy_nocheck(const char *src, char *dst, int len,
64 * Fold a partial checksum without adding pseudo headers
66 static inline unsigned short int csum_fold(unsigned int sum)
69 ".set\tnoat\t\t\t# csum_fold\n\t"
84 * This is a version of ip_compute_csum() optimized for IP headers,
85 * which always checksum on 4 octet boundaries.
87 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
90 static inline unsigned short ip_fast_csum(unsigned char *iph,
97 * This is for 32-bit processors ... but works just fine for 64-bit
98 * processors for now ... XXX
100 __asm__ __volatile__(
101 ".set\tnoreorder\t\t\t# ip_fast_csum\n\t"
109 "sltu\t$1, %0, %3\n\t"
113 "sltu\t$1, %0, %3\n\t"
117 "sltu\t$1, %0, %3\n\t"
120 "1:\tlw\t%3, 16(%1)\n\t"
123 "sltu\t$1, %0, %3\n\t"
124 "bne\t%2, %1, 1b\n\t"
129 : "=&r" (sum), "=&r" (iph), "=&r" (ihl), "=&r" (dummy)
130 : "1" (iph), "2" (ihl));
132 return csum_fold(sum);
136 * computes the checksum of the TCP/UDP pseudo-header
137 * returns a 16-bit checksum, already complemented
139 * Cast unsigned short expressions to unsigned long explicitly
140 * to avoid surprises resulting from implicit promotions to
141 * signed int. --macro
143 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
146 unsigned short proto,
150 ".set\tnoat\t\t\t# csum_tcpudp_nofold\n\t"
154 "dsll32\t$1, %0, 0\n\t"
156 "dsrl32\t%0, %0, 0\n\t"
159 : "0" (daddr), "r"(saddr),
161 "r" (((unsigned long)ntohs(len)<<16)+proto*256),
163 "r" (((unsigned long)(proto)<<16)+len),
171 * computes the checksum of the TCP/UDP pseudo-header
172 * returns a 16-bit checksum, already complemented
174 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
177 unsigned short proto,
180 return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
184 * this routine is used for miscellaneous IP-like checksums, mainly
187 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
189 return csum_fold(csum_partial(buff, len, 0));
192 #define _HAVE_ARCH_IPV6_CSUM
193 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
194 struct in6_addr *daddr,
196 unsigned short proto,
200 ".set\tpush\t\t\t# csum_ipv6_magic\n\t"
201 ".set\tnoreorder\n\t"
203 "addu\t%0, %5\t\t\t# proto (long in network byte order)\n\t"
204 "sltu\t$1, %0, %5\n\t"
207 "addu\t%0, %6\t\t\t# csum\n\t"
208 "sltu\t$1, %0, %6\n\t"
209 "lw\t%1, 0(%2)\t\t\t# four words source address\n\t"
212 "sltu\t$1, %0, %1\n\t"
217 "sltu\t$1, %0, %1\n\t"
222 "sltu\t$1, %0, %1\n\t"
227 "sltu\t$1, %0, %1\n\t"
232 "sltu\t$1, %0, %1\n\t"
237 "sltu\t$1, %0, %1\n\t"
242 "sltu\t$1, %0, %1\n\t"
247 "sltu\t$1, %0, %1\n\t"
249 "addu\t%0, $1\t\t\t# Add final carry\n\t"
251 : "=&r" (sum), "=&r" (proto)
252 : "r" (saddr), "r" (daddr),
253 "0" (htonl(len)), "1" (htonl(proto)), "r" (sum));
255 return csum_fold(sum);
258 #endif /* _ASM_CHECKSUM_H */