1 #ifndef _I386_CHECKSUM_H
2 #define _I386_CHECKSUM_H
6 #include <asm/uaccess.h>
9 * computes the checksum of a memory block at buff, length len,
10 * and adds in "sum" (32-bit)
12 * returns a 32-bit number suitable for feeding into itself
13 * or csum_tcpudp_magic
15 * this function must be called with even lengths, except
16 * for the last fragment, which may be odd
18 * it's best to have buff aligned on a 32-bit boundary
20 asmlinkage unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
23 * the same as csum_partial, but copies from src while it
24 * checksums, and handles user-space pointer exceptions correctly, when needed.
26 * here even more important to align src and dst on a 32-bit (or even
27 * better 64-bit) boundary
30 asmlinkage unsigned int csum_partial_copy_generic(const unsigned char *src, unsigned char *dst,
31 int len, int sum, int *src_err_ptr, int *dst_err_ptr);
34 * Note: when you get a NULL pointer exception here this means someone
35 * passed in an incorrect kernel address to one of these functions.
37 * If you use these functions directly please don't forget the
41 unsigned int csum_partial_copy_nocheck (const unsigned char *src, unsigned char *dst,
44 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
48 unsigned int csum_partial_copy_from_user(const unsigned char __user *src, unsigned char *dst,
49 int len, int sum, int *err_ptr)
52 return csum_partial_copy_generic((__force unsigned char *)src, dst,
53 len, sum, err_ptr, NULL);
57 * This is a version of ip_compute_csum() optimized for IP headers,
58 * which always checksum on 4 octet boundaries.
60 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
63 static inline unsigned short ip_fast_csum(unsigned char * iph,
75 "1: adcl 16(%1), %0 ;\n"
86 /* Since the input registers which are loaded with iph and ipl
87 are modified, we must also specify them as outputs, or gcc
88 will assume they contain their original values. */
89 : "=r" (sum), "=r" (iph), "=r" (ihl)
90 : "1" (iph), "2" (ihl)
96 * Fold a partial checksum
99 static inline unsigned int csum_fold(unsigned int sum)
103 "adcl $0xffff, %0 ;\n"
105 : "r" (sum << 16), "0" (sum & 0xffff0000)
110 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
113 unsigned short proto,
122 : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
127 * computes the checksum of the TCP/UDP pseudo-header
128 * returns a 16-bit checksum, already complemented
130 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
133 unsigned short proto,
136 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
140 * this routine is used for miscellaneous IP-like checksums, mainly
144 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
146 return csum_fold (csum_partial(buff, len, 0));
149 #define _HAVE_ARCH_IPV6_CSUM
150 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
151 struct in6_addr *daddr,
153 unsigned short proto,
160 "adcl 12(%1), %0 ;\n"
164 "adcl 12(%2), %0 ;\n"
169 : "r" (saddr), "r" (daddr),
170 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
172 return csum_fold(sum);
176 * Copy and checksum to user
178 #define HAVE_CSUM_COPY_USER
179 static __inline__ unsigned int csum_and_copy_to_user(const unsigned char *src,
180 unsigned char __user *dst,
185 if (access_ok(VERIFY_WRITE, dst, len))
186 return csum_partial_copy_generic(src, (__force unsigned char *)dst, len, sum, NULL, err_ptr);
191 return -1; /* invalid checksum */