1 /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
3 #ifndef _CRIS_CHECKSUM_H
4 #define _CRIS_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 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
24 * here even more important to align src and dst on a 32-bit (or even
25 * better 64-bit) boundary
28 unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
29 int len, unsigned int sum);
32 * Fold a partial checksum into a word
35 extern inline unsigned int csum_fold(unsigned int sum)
37 /* the while loop is unnecessary really, it's always enough with two
41 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
46 /* Checksum some values used in TCP/UDP headers.
48 * The gain by doing this in asm is that C will not generate carry-additions
49 * for the 32-bit components of the checksum, so otherwise we would have had
50 * to split all of those into 16-bit components, then add.
53 extern inline unsigned int
54 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
55 unsigned short proto, unsigned int sum)
58 __asm__ ("add.d %2, %0\n\t"
66 : "0" (sum), "r" (daddr), "r" (saddr), "r" ((ntohs(len) << 16) + (proto << 8)));
71 extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
72 int len, unsigned int sum,
76 * This is a version of ip_compute_csum() optimized for IP headers,
77 * which always checksum on 4 octet boundaries.
81 extern inline unsigned short ip_fast_csum(unsigned char * iph,
84 return csum_fold(csum_partial(iph, ihl * 4, 0));
88 * computes the checksum of the TCP/UDP pseudo-header
89 * returns a 16-bit checksum, already complemented
92 extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
98 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
102 * this routine is used for miscellaneous IP-like checksums, mainly
106 extern inline unsigned short ip_compute_csum(unsigned char * buff, int len) {
107 return csum_fold (csum_partial(buff, len, 0));