1 #ifndef _S390_CHECKSUM_H
2 #define _S390_CHECKSUM_H
5 * include/asm-s390/checksum.h
6 * S390 fast network checksum routines
7 * see also arch/S390/lib/checksum.c
10 * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
11 * Author(s): Ulrich Hild (first version)
12 * Martin Schwidefsky (heavily optimized CKSM version)
13 * D.J. Barrow (third attempt)
16 #include <asm/uaccess.h>
19 * computes the checksum of a memory block at buff, length len,
20 * and adds in "sum" (32-bit)
22 * returns a 32-bit number suitable for feeding into itself
23 * or csum_tcpudp_magic
25 * this function must be called with even lengths, except
26 * for the last fragment, which may be odd
28 * it's best to have buff aligned on a 32-bit boundary
31 csum_partial(const unsigned char * buff, int len, unsigned int sum);
34 * csum_partial as an inline function
36 extern inline unsigned int
37 csum_partial_inline(const unsigned char * buff, int len, unsigned int sum)
41 rp.subreg.even = (unsigned long) buff;
42 rp.subreg.odd = (unsigned long) len;
43 __asm__ __volatile__ (
44 "0: cksm %0,%1\n" /* do checksum on longs */
46 : "+&d" (sum), "+&a" (rp) : : "cc" );
51 * the same as csum_partial, but copies from src while it
54 * here even more important to align src and dst on a 32-bit (or even
55 * better 64-bit) boundary
58 extern inline unsigned int
59 csum_partial_copy(const char *src, char *dst, int len,unsigned int sum)
62 return csum_partial_inline(dst, len, sum);
66 * the same as csum_partial_copy, but copies from user space.
68 * here even more important to align src and dst on a 32-bit (or even
69 * better 64-bit) boundary
71 * Copy from userspace and compute checksum. If we catch an exception
72 * then zero the rest of the buffer.
74 extern inline unsigned int
75 csum_partial_copy_from_user (const char *src, char *dst,
76 int len, unsigned int sum,
81 missing = copy_from_user(dst, src, len);
83 memset(dst + len - missing, 0, missing);
87 return csum_partial(dst, len, sum);
91 extern inline unsigned int
92 csum_partial_copy_nocheck (const char *src, char *dst, int len, unsigned int sum)
95 return csum_partial_inline(dst, len, sum);
99 * Fold a partial checksum without adding pseudo headers
102 unsigned short csum_fold(unsigned int sum);
104 extern inline unsigned short
105 csum_fold(unsigned int sum)
109 __asm__ __volatile__ (
110 " slr %N1,%N1\n" /* %0 = H L */
111 " lr %1,%0\n" /* %0 = H L, %1 = H L 0 0 */
112 " srdl %1,16\n" /* %0 = H L, %1 = 0 H L 0 */
113 " alr %1,%N1\n" /* %0 = H L, %1 = L H L 0 */
114 " alr %0,%1\n" /* %0 = H+L+C L+H */
115 " srl %0,16\n" /* %0 = H+L+C */
116 : "+&d" (sum), "=d" (rp) : : "cc" );
117 return ((unsigned short) ~sum);
122 * This is a version of ip_compute_csum() optimized for IP headers,
123 * which always checksum on 4 octet boundaries.
126 extern inline unsigned short
127 ip_fast_csum(unsigned char *iph, unsigned int ihl)
132 rp.subreg.even = (unsigned long) iph;
133 rp.subreg.odd = (unsigned long) ihl*4;
134 __asm__ __volatile__ (
135 " sr %0,%0\n" /* set sum to zero */
136 "0: cksm %0,%1\n" /* do checksum on longs */
138 : "=&d" (sum), "+&a" (rp) : : "cc" );
139 return csum_fold(sum);
143 * computes the checksum of the TCP/UDP pseudo-header
144 * returns a 32-bit checksum
146 extern inline unsigned int
147 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
148 unsigned short len, unsigned short proto,
151 __asm__ __volatile__ (
152 " alr %0,%1\n" /* sum += saddr */
154 " ahi %0,1\n" /* add carry */
156 : "+&d" (sum) : "d" (saddr) : "cc" );
157 __asm__ __volatile__ (
158 " alr %0,%1\n" /* sum += daddr */
160 " ahi %0,1\n" /* add carry */
162 : "+&d" (sum) : "d" (daddr) : "cc" );
163 __asm__ __volatile__ (
164 " alr %0,%1\n" /* sum += (len<<16) + (proto<<8) */
166 " ahi %0,1\n" /* add carry */
169 : "d" (((unsigned int) len<<16) + (unsigned int) proto)
175 * computes the checksum of the TCP/UDP pseudo-header
176 * returns a 16-bit checksum, already complemented
179 extern inline unsigned short int
180 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
181 unsigned short len, unsigned short proto,
184 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
188 * this routine is used for miscellaneous IP-like checksums, mainly
192 extern inline unsigned short
193 ip_compute_csum(unsigned char * buff, int len)
195 return csum_fold(csum_partial(buff, len, 0));
198 #endif /* _S390_CHECKSUM_H */