/* SPDX-License-Identifier: GPL-2.0 *//* include/net/dsfield.h - Manipulation of the Differentiated Services field */ /* Written 1998-2000 by Werner Almesberger, EPFL ICA */  #ifndef __NET_DSFIELD_H#define __NET_DSFIELD_H #include <linux/types.h>#include <linux/ip.h>#include <linux/ipv6.h>#include <asm/byteorder.h>  static inline __u8 ipv4_get_dsfield(const struct iphdr *iph){	return iph->tos;}  static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h){	return ntohs(*(__force const __be16 *)ipv6h) >> 4;}  static inline void ipv4_change_dsfield(struct iphdr *iph,__u8 mask,    __u8 value){        __u32 check = ntohs((__force __be16)iph->check);	__u8 dsfield; 	dsfield = (iph->tos & mask) | value;	check += iph->tos;	if ((check+1) >> 16) check = (check+1) & 0xffff;	check -= dsfield;	check += check >> 16; /* adjust carry */	iph->check = (__force __sum16)htons(check);	iph->tos = dsfield;}  static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,    __u8 value){	__be16 *p = (__force __be16 *)ipv6h; 	*p = (*p & htons((((u16)mask << 4) | 0xf00f))) | htons((u16)value << 4);}  #endif