1 /* TODO: csum_tcpudp_magic could be speeded up, and csum_fold as well */
2
3 #ifndef _CRIS_CHECKSUM_H
4 #define _CRIS_CHECKSUM_H
5
6 /*
7 * computes the checksum of a memory block at buff, length len,
8 * and adds in "sum" (32-bit)
9 *
10 * returns a 32-bit number suitable for feeding into itself
11 * or csum_tcpudp_magic
12 *
13 * this function must be called with even lengths, except
14 * for the last fragment, which may be odd
15 *
16 * it's best to have buff aligned on a 32-bit boundary
17 */
18 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
19
20 /*
21 * the same as csum_partial, but copies from src while it
22 * checksums
23 *
24 * here even more important to align src and dst on a 32-bit (or even
25 * better 64-bit) boundary
26 */
27
28 unsigned int csum_partial_copy_nocheck(const char *src, char *dst,
29 int len, unsigned int sum);
30
31 /*
32 * Fold a partial checksum into a word
33 */
34
csum_fold(unsigned int sum)35 extern inline unsigned int csum_fold(unsigned int sum)
36 {
37 /* the while loop is unnecessary really, it's always enough with two
38 iterations */
39
40 while(sum >> 16)
41 sum = (sum & 0xffff) + (sum >> 16); /* add in end-around carry */
42
43 return ~sum;
44 }
45
46 /* Checksum some values used in TCP/UDP headers.
47 *
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.
51 */
52
53 extern inline unsigned int
csum_tcpudp_nofold(unsigned long saddr,unsigned long daddr,unsigned short len,unsigned short proto,unsigned int sum)54 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
55 unsigned short proto, unsigned int sum)
56 {
57 int res;
58 __asm__ ("add.d %2, %0\n\t"
59 "ax\n\t"
60 "add.d %3, %0\n\t"
61 "ax\n\t"
62 "add.d %4, %0\n\t"
63 "ax\n\t"
64 "addq 0, %0\n"
65 : "=r" (res)
66 : "0" (sum), "r" (daddr), "r" (saddr), "r" ((ntohs(len) << 16) + (proto << 8)));
67
68 return res;
69 }
70
71 extern unsigned int csum_partial_copy_from_user(const char *src, char *dst,
72 int len, unsigned int sum,
73 int *errptr);
74
75 /*
76 * This is a version of ip_compute_csum() optimized for IP headers,
77 * which always checksum on 4 octet boundaries.
78 *
79 */
80
ip_fast_csum(unsigned char * iph,unsigned int ihl)81 extern inline unsigned short ip_fast_csum(unsigned char * iph,
82 unsigned int ihl)
83 {
84 return csum_fold(csum_partial(iph, ihl * 4, 0));
85 }
86
87 /*
88 * computes the checksum of the TCP/UDP pseudo-header
89 * returns a 16-bit checksum, already complemented
90 */
91
csum_tcpudp_magic(unsigned long saddr,unsigned long daddr,unsigned short len,unsigned short proto,unsigned int sum)92 extern inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
93 unsigned long daddr,
94 unsigned short len,
95 unsigned short proto,
96 unsigned int sum)
97 {
98 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
99 }
100
101 /*
102 * this routine is used for miscellaneous IP-like checksums, mainly
103 * in icmp.c
104 */
105
ip_compute_csum(unsigned char * buff,int len)106 extern inline unsigned short ip_compute_csum(unsigned char * buff, int len) {
107 return csum_fold (csum_partial(buff, len, 0));
108 }
109
110 #endif
111