1 #ifndef _I386_CHECKSUM_H
2 #define _I386_CHECKSUM_H
6 * computes the checksum of a memory block at buff, length len,
7 * and adds in "sum" (32-bit)
9 * returns a 32-bit number suitable for feeding into itself
10 * or csum_tcpudp_magic
12 * this function must be called with even lengths, except
13 * for the last fragment, which may be odd
15 * it's best to have buff aligned on a 32-bit boundary
17 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
20 * the same as csum_partial, but copies from src while it
21 * checksums, and handles user-space pointer exceptions correctly, when needed.
23 * here even more important to align src and dst on a 32-bit (or even
24 * better 64-bit) boundary
27 asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,
28 int *src_err_ptr, int *dst_err_ptr);
31 * Note: when you get a NULL pointer exception here this means someone
32 * passed in an incorrect kernel address to one of these functions.
34 * If you use these functions directly please don't forget the
38 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
41 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
45 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
46 int len, int sum, int *err_ptr)
48 return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
52 * These are the old (and unsafe) way of doing checksums, a warning message will be
53 * printed if they are used and an exeption occurs.
55 * these functions should go away after some time.
58 #define csum_partial_copy_fromuser csum_partial_copy
59 unsigned int csum_partial_copy( const char *src, char *dst, int len, int sum);
62 * This is a version of ip_compute_csum() optimized for IP headers,
63 * which always checksum on 4 octet boundaries.
65 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
68 static inline unsigned short ip_fast_csum(unsigned char * iph,
80 "1: adcl 16(%1), %0 ;\n"
91 /* Since the input registers which are loaded with iph and ipl
92 are modified, we must also specify them as outputs, or gcc
93 will assume they contain their original values. */
94 : "=r" (sum), "=r" (iph), "=r" (ihl)
95 : "1" (iph), "2" (ihl));
100 * Fold a partial checksum
103 static inline unsigned int csum_fold(unsigned int sum)
107 "adcl $0xffff, %0 ;\n"
109 : "r" (sum << 16), "0" (sum & 0xffff0000)
114 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
117 unsigned short proto,
126 : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
131 * computes the checksum of the TCP/UDP pseudo-header
132 * returns a 16-bit checksum, already complemented
134 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
137 unsigned short proto,
140 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
144 * this routine is used for miscellaneous IP-like checksums, mainly
148 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
150 return csum_fold (csum_partial(buff, len, 0));
153 #define _HAVE_ARCH_IPV6_CSUM
154 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
155 struct in6_addr *daddr,
157 unsigned short proto,
164 "adcl 12(%1), %0 ;\n"
168 "adcl 12(%2), %0 ;\n"
173 : "r" (saddr), "r" (daddr),
174 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
176 return csum_fold(sum);
180 * Copy and checksum to user
182 #define HAVE_CSUM_COPY_USER
183 static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst,
184 int len, int sum, int *err_ptr)
186 if (access_ok(VERIFY_WRITE, dst, len))
187 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
192 return -1; /* invalid checksum */