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 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 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 unsigned int csum_partial_copy_nocheck ( const char *src
, char *dst
,
34 int *src_err_ptr
=NULL
, *dst_err_ptr
=NULL
;
36 return csum_partial_copy_generic ( src
, dst
, len
, sum
, src_err_ptr
, dst_err_ptr
);
40 unsigned int csum_partial_copy_from_user ( const char *src
, char *dst
,
41 int len
, int sum
, int *err_ptr
)
43 int *dst_err_ptr
=NULL
;
45 return csum_partial_copy_generic ( src
, dst
, len
, sum
, err_ptr
, dst_err_ptr
);
50 /* Not used at the moment. It is difficult to imagine for what purpose
51 it can be used :-) Please, do not forget to verify_area before it --ANK
55 * This combination is currently not used, but possible:
59 unsigned int csum_partial_copy_to_user ( const char *src
, char *dst
,
60 int len
, int sum
, int *err_ptr
)
62 int *src_err_ptr
=NULL
;
64 return csum_partial_copy_generic ( src
, dst
, len
, sum
, src_err_ptr
, err_ptr
);
69 * These are the old (and unsafe) way of doing checksums, a warning message will be
70 * printed if they are used and an exeption occurs.
72 * these functions should go away after some time.
75 #define csum_partial_copy_fromuser csum_partial_copy
76 unsigned int csum_partial_copy( const char *src
, char *dst
, int len
, int sum
);
79 * This is a version of ip_compute_csum() optimized for IP headers,
80 * which always checksum on 4 octet boundaries.
82 * By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
85 static inline unsigned short ip_fast_csum(unsigned char * iph
,
89 __asm__
__volatile__("
108 /* Since the input registers which are loaded with iph and ipl
109 are modified, we must also specify them as outputs, or gcc
110 will assume they contain their original values. */
111 : "=r" (sum
), "=r" (iph
), "=r" (ihl
)
112 : "1" (iph
), "2" (ihl
));
117 * Fold a partial checksum
120 static inline unsigned int csum_fold(unsigned int sum
)
127 : "r" (sum
<< 16), "0" (sum
& 0xffff0000)
132 static inline unsigned long csum_tcpudp_nofold(unsigned long saddr
,
135 unsigned short proto
,
145 : "g" (daddr
), "g"(saddr
), "g"((ntohs(len
)<<16)+proto
*256), "0"(sum
));
150 * computes the checksum of the TCP/UDP pseudo-header
151 * returns a 16-bit checksum, already complemented
153 static inline unsigned short int csum_tcpudp_magic(unsigned long saddr
,
156 unsigned short proto
,
159 return csum_fold(csum_tcpudp_nofold(saddr
,daddr
,len
,proto
,sum
));
163 * this routine is used for miscellaneous IP-like checksums, mainly
167 static inline unsigned short ip_compute_csum(unsigned char * buff
, int len
) {
168 return csum_fold (csum_partial(buff
, len
, 0));
171 #define _HAVE_ARCH_IPV6_CSUM
172 static __inline__
unsigned short int csum_ipv6_magic(struct in6_addr
*saddr
,
173 struct in6_addr
*daddr
,
175 unsigned short proto
,
192 : "r" (saddr
), "r" (daddr
),
193 "r"(htonl((__u32
) (len
))), "r"(htonl(proto
)), "0"(sum
));
195 return csum_fold(sum
);
199 * Copy and checksum to user
201 #define HAVE_CSUM_COPY_USER
202 static __inline__
unsigned int csum_and_copy_to_user (const char *src
, char *dst
,
203 int len
, int sum
, int *err_ptr
)
205 int *src_err_ptr
=NULL
;
207 if (verify_area(VERIFY_WRITE
, dst
, len
) == 0)
208 return csum_partial_copy_generic(src
, dst
, len
, sum
, src_err_ptr
, err_ptr
);