1 /* include/net/dsfield.h - Manipulation of the Differentiated Services field */
2
3 /* Written 1998-2000 by Werner Almesberger, EPFL ICA */
4
5
6 #ifndef __NET_DSFIELD_H
7 #define __NET_DSFIELD_H
8
9 #include <linux/types.h>
10 #include <linux/ip.h>
11 #include <linux/ipv6.h>
12 #include <asm/byteorder.h>
13
14
15 static inline __u8 ipv4_get_dsfield(struct iphdr *iph)
16 {
17 return iph->tos;
18 }
19
20
21 static inline __u8 ipv6_get_dsfield(struct ipv6hdr *ipv6h)
22 {
23 return ntohs(*(__u16 *) ipv6h) >> 4;
24 }
25
26
27 static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,
28 __u8 value)
29 {
30 __u32 check = ntohs(iph->check);
31 __u8 dsfield;
32
33 dsfield = (iph->tos & mask) | value;
34 check += iph->tos;
35 if ((check+1) >> 16) check = (check+1) & 0xffff;
36 check -= dsfield;
37 check += check >> 16; /* adjust carry */
38 iph->check = htons(check);
39 iph->tos = dsfield;
40 }
41
42
43 static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,
44 __u8 value)
45 {
46 __u16 tmp;
47
48 tmp = ntohs(*(__u16 *) ipv6h);
49 tmp = (tmp & ((mask << 4) | 0xf00f)) | (value << 4);
50 *(__u16 *) ipv6h = htons(tmp);
51 }
52
53
54 #if 0 /* put this later into asm-i386 or such ... */
55
56 static inline void ip_change_dsfield(struct iphdr *iph,__u16 dsfield)
57 {
58 __u16 check;
59
60 __asm__ __volatile__("
61 movw 10(%1),%0
62 xchg %b0,%h0
63 addb 1(%1),%b0
64 adcb $0,%h0
65 adcw $1,%0
66 cmc
67 sbbw %2,%0
68 sbbw $0,%0
69 movb %b2,1(%1)
70 xchg %b0,%h0
71 movw %0,10(%1)"
72 : "=&r" (check)
73 : "r" (iph), "r" (dsfield)
74 : "cc");
75 }
76
77 #endif
78
79 #endif
80
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