xref: /openbmc/linux/include/net/dsfield.h (revision 1f1c1d7c)
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 
ipv4_get_dsfield(const struct iphdr * iph)16 static inline __u8 ipv4_get_dsfield(const struct iphdr *iph)
17 {
18 	return iph->tos;
19 }
20 
21 
ipv6_get_dsfield(const struct ipv6hdr * ipv6h)22 static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h)
23 {
24 	return ntohs(*(__force const __be16 *)ipv6h) >> 4;
25 }
26 
27 
ipv4_change_dsfield(struct iphdr * iph,__u8 mask,__u8 value)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 
ipv6_change_dsfield(struct ipv6hdr * ipv6h,__u8 mask,__u8 value)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