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 __wsum csum_partial(const void *buff, int len, __wsum 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 __wsum csum_partial_copy_generic(const void *src, void *dst,
31 int len, __wsum 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 __wsum csum_partial_copy_nocheck (const void *src, void *dst,
44 return csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
48 __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
49 int len, __wsum sum, int *err_ptr)
52 return csum_partial_copy_generic((__force void *)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 __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
74 "1: adcl 16(%1), %0 ;\n"
85 /* Since the input registers which are loaded with iph and ihl
86 are modified, we must also specify them as outputs, or gcc
87 will assume they contain their original values. */
88 : "=r" (sum), "=r" (iph), "=r" (ihl)
89 : "1" (iph), "2" (ihl)
91 return (__force __sum16)sum;
95 * Fold a partial checksum
98 static inline __sum16 csum_fold(__wsum sum)
102 "adcl $0xffff, %0 ;\n"
104 : "r" ((__force u32)sum << 16),
105 "0" ((__force u32)sum & 0xffff0000)
107 return (__force __sum16)(~(__force u32)sum >> 16);
110 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
112 unsigned short proto,
121 : "g" (daddr), "g"(saddr), "g"((len + proto) << 8), "0"(sum));
126 * computes the checksum of the TCP/UDP pseudo-header
127 * returns a 16-bit checksum, already complemented
129 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
131 unsigned short proto,
134 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
138 * this routine is used for miscellaneous IP-like checksums, mainly
142 static inline __sum16 ip_compute_csum(const void *buff, int len)
144 return csum_fold (csum_partial(buff, len, 0));
147 #define _HAVE_ARCH_IPV6_CSUM
148 static __inline__ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
149 const struct in6_addr *daddr,
150 __u32 len, unsigned short proto,
157 "adcl 12(%1), %0 ;\n"
161 "adcl 12(%2), %0 ;\n"
166 : "r" (saddr), "r" (daddr),
167 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
169 return csum_fold(sum);
173 * Copy and checksum to user
175 #define HAVE_CSUM_COPY_USER
176 static __inline__ __wsum csum_and_copy_to_user(const void *src,
182 if (access_ok(VERIFY_WRITE, dst, len))
183 return csum_partial_copy_generic(src, (__force void *)dst, len, sum, NULL, err_ptr);
188 return (__force __wsum)-1; /* invalid checksum */