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