include/net/dsfield.h

   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
  15 static inline __u8 ipv4_get_dsfield(const struct iphdr *iph)
  16 {
  17         return iph->tos;
  18 }
  19
  20
  21 static inline __u8 ipv6_get_dsfield(const struct ipv6hdr *ipv6h)
  22 {
  23         return ntohs(*(const __be16 *)ipv6h) >> 4;
  24 }
  25
  26
  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
  43 static inline void ipv6_change_dsfield(struct ipv6hdr *ipv6h,__u8 mask,
  44     __u8 value)
  45 {
  46         __be16 *p = (__force __be16 *)ipv6h;
  47
  48         *p = (*p & htons((((u16)mask << 4) | 0xf00f))) | htons((u16)value << 4);
  49 }
  50
  51
  52 #endif