1 #ifndef _I386_CHECKSUM_H
2 #define _I386_CHECKSUM_H
7 * computes the checksum of a memory block at buff, length len,
8 * and adds in "sum" (32-bit)
10 * returns a 32-bit number suitable for feeding into itself
11 * or csum_tcpudp_magic
13 * this function must be called with even lengths, except
14 * for the last fragment, which may be odd
16 * it's best to have buff aligned on a 32-bit boundary
18 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
21 * the same as csum_partial, but copies from src while it
22 * checksums, and handles user-space pointer exceptions correctly, when needed.
24 * here even more important to align src and dst on a 32-bit (or even
25 * better 64-bit) boundary
28 asmlinkage unsigned int csum_partial_copy_generic( const char *src, char *dst, int len, int sum,
29 int *src_err_ptr, int *dst_err_ptr);
32 * Note: when you get a NULL pointer exception here this means someone
33 * passed in an incorrect kernel address to one of these functions.
35 * If you use these functions directly please don't forget the
39 unsigned int csum_partial_copy_nocheck ( const char *src, char *dst,
42 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
46 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
47 int len, int sum, int *err_ptr)
49 return csum_partial_copy_generic ( src, dst, len, sum, err_ptr, NULL);
53 * This is a version of ip_compute_csum() optimized for IP headers,
54 * which always checksum on 4 octet boundaries.
56 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
59 static inline unsigned short ip_fast_csum(unsigned char * iph,
71 "1: adcl 16(%1), %0 ;\n"
82 /* Since the input registers which are loaded with iph and ipl
83 are modified, we must also specify them as outputs, or gcc
84 will assume they contain their original values. */
85 : "=r" (sum), "=r" (iph), "=r" (ihl)
86 : "1" (iph), "2" (ihl)
92 * Fold a partial checksum
95 static inline unsigned int csum_fold(unsigned int sum)
99 "adcl $0xffff, %0 ;\n"
101 : "r" (sum << 16), "0" (sum & 0xffff0000)
106 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
109 unsigned short proto,
118 : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
123 * computes the checksum of the TCP/UDP pseudo-header
124 * returns a 16-bit checksum, already complemented
126 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
129 unsigned short proto,
132 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
136 * this routine is used for miscellaneous IP-like checksums, mainly
140 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
142 return csum_fold (csum_partial(buff, len, 0));
145 #define _HAVE_ARCH_IPV6_CSUM
146 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
147 struct in6_addr *daddr,
149 unsigned short proto,
156 "adcl 12(%1), %0 ;\n"
160 "adcl 12(%2), %0 ;\n"
165 : "r" (saddr), "r" (daddr),
166 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
168 return csum_fold(sum);
172 * Copy and checksum to user
174 #define HAVE_CSUM_COPY_USER
175 static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst,
176 int len, int sum, int *err_ptr)
178 if (access_ok(VERIFY_WRITE, dst, len))
179 return csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
184 return -1; /* invalid checksum */