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 
ipv4_get_dsfield(const struct iphdr * iph)15 static inline __u8 ipv4_get_dsfield(const struct iphdr *iph)
16 {
17 	return iph->tos;
18 }
19 
20 
ipv6_get_dsfield(const struct ipv6hdr * ipv6h)21 static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h)
22 {
23 	return ntohs(*(const __be16 *)ipv6h) >> 4;
24 }
25 
26 
ipv4_change_dsfield(struct iphdr * iph,__u8 mask,__u8 value)27 static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,
28     __u8 value)
29 {
30         __u32 check = ntohs((__force __be16)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 = (__force __sum16)htons(check);
39 	iph->tos = dsfield;
40 }
41 
42 
ipv6_change_dsfield(struct ipv6hdr * ipv6h,__u8 mask,__u8 value)43 static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,
44     __u8 value)
45 {
46         __u16 tmp;
47 
48 	tmp = ntohs(*(__be16 *) ipv6h);
49 	tmp = (tmp & ((mask << 4) | 0xf00f)) | (value << 4);
50 	*(__be16 *) ipv6h = htons(tmp);
51 }
52 
53 
54 #endif
55