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 direct_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,
43 * The direct function is OK for kernel-space => kernel-space copies:
45 return direct_csum_partial_copy_generic ( src, dst, len, sum, NULL, NULL);
49 unsigned int csum_partial_copy_from_user ( const char *src, char *dst,
50 int len, int sum, int *err_ptr)
52 if (copy_from_user(dst, src, len))
54 return csum_partial(dst, len, sum);
58 * This is a version of ip_compute_csum() optimized for IP headers,
59 * which always checksum on 4 octet boundaries.
61 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
64 static inline unsigned short ip_fast_csum(unsigned char * iph,
76 "1: adcl 16(%1), %0 ;\n"
87 /* Since the input registers which are loaded with iph and ipl
88 are modified, we must also specify them as outputs, or gcc
89 will assume they contain their original values. */
90 : "=r" (sum), "=r" (iph), "=r" (ihl)
91 : "1" (iph), "2" (ihl)
97 * Fold a partial checksum
100 static inline unsigned int csum_fold(unsigned int sum)
104 "adcl $0xffff, %0 ;\n"
106 : "r" (sum << 16), "0" (sum & 0xffff0000)
111 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr,
114 unsigned short proto,
123 : "g" (daddr), "g"(saddr), "g"((ntohs(len)<<16)+proto*256), "0"(sum));
128 * computes the checksum of the TCP/UDP pseudo-header
129 * returns a 16-bit checksum, already complemented
131 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
134 unsigned short proto,
137 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
141 * this routine is used for miscellaneous IP-like checksums, mainly
145 static inline unsigned short ip_compute_csum(unsigned char * buff, int len)
147 return csum_fold (csum_partial(buff, len, 0));
150 #define _HAVE_ARCH_IPV6_CSUM
151 static __inline__ unsigned short int csum_ipv6_magic(struct in6_addr *saddr,
152 struct in6_addr *daddr,
154 unsigned short proto,
161 "adcl 12(%1), %0 ;\n"
165 "adcl 12(%2), %0 ;\n"
170 : "r" (saddr), "r" (daddr),
171 "r"(htonl(len)), "r"(htonl(proto)), "0"(sum));
173 return csum_fold(sum);
177 * Copy and checksum to user
179 #define HAVE_CSUM_COPY_USER
180 static __inline__ unsigned int direct_csum_and_copy_to_user(const char *src, char *dst,
181 int len, int sum, int *err_ptr)
183 if (access_ok(VERIFY_WRITE, dst, len))
184 return direct_csum_partial_copy_generic(src, dst, len, sum, NULL, err_ptr);
189 return -1; /* invalid checksum */
192 static __inline__ unsigned int csum_and_copy_to_user(const char *src, char *dst,
193 int len, int sum, int *err_ptr)
195 if (access_ok(VERIFY_WRITE, dst, len)) {
196 if (copy_to_user(dst, src, len))
198 return csum_partial(src, len, sum);
204 return -1; /* invalid checksum */