1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* include/net/dsfield.h - Manipulation of the Differentiated Services field */
3
4 /* Written 1998-2000 by Werner Almesberger, EPFL ICA */
5
6
7 #ifndef __NET_DSFIELD_H
8 #define __NET_DSFIELD_H
9
10 #include <linux/types.h>
11 #include <linux/ip.h>
12 #include <linux/ipv6.h>
13 #include <asm/byteorder.h>
14
15
16 static inline __u8 ipv4_get_dsfield(const struct iphdr *iph)
17 {
18 return iph->tos;
19 }
20
21
22 static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h)
23 {
24 return ntohs(*(__force const __be16 *)ipv6h) >> 4;
25 }
26
27
28 static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,
29 __u8 value)
30 {
31 __u32 check = ntohs((__force __be16)iph->check);
32 __u8 dsfield;
33
34 dsfield = (iph->tos & mask) | value;
35 check += iph->tos;
36 if ((check+1) >> 16) check = (check+1) & 0xffff;
37 check -= dsfield;
38 check += check >> 16; /* adjust carry */
39 iph->check = (__force __sum16)htons(check);
40 iph->tos = dsfield;
41 }
42
43
44 static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,
45 __u8 value)
46 {
47 __be16 *p = (__force __be16 *)ipv6h;
48
49 *p = (*p & htons((((u16)mask << 4) | 0xf00f))) | htons((u16)value << 4);
50 }
51
52
53 #endif
54
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