root/include/net/dsfield.h

INCLUDED FROM

DEFINITIONS

1. ipv4_get_dsfield
2. ipv6_get_dsfield
3. ipv4_change_dsfield
4. ipv6_change_dsfield

/* 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(*(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)
{
        __u16 tmp;

        tmp = ntohs(*(__be16 *) ipv6h);
        tmp = (tmp & ((mask << 4) | 0xf00f)) | (value << 4);
        *(__be16 *) ipv6h = htons(tmp);
}


#endif