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#ifndef _INET_ECN_H_
#define _INET_ECN_H_
#include <linux/ip.h>
#include <linux/skbuff.h>
#include <net/inet_sock.h>
#include <net/dsfield.h>
enum {
INET_ECN_NOT_ECT = 0,
INET_ECN_ECT_1 = 1,
INET_ECN_ECT_0 = 2,
INET_ECN_CE = 3,
INET_ECN_MASK = 3,
};
static inline int INET_ECN_is_ce(__u8 dsfield)
{
return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
}
static inline int INET_ECN_is_not_ect(__u8 dsfield)
{
return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
}
static inline int INET_ECN_is_capable(__u8 dsfield)
{
return (dsfield & INET_ECN_ECT_0);
}
static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
{
outer &= ~INET_ECN_MASK;
outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
INET_ECN_ECT_0;
return outer;
}
#define INET_ECN_xmit(sk) do { inet_sk(sk)->tos |= INET_ECN_ECT_0; } while (0)
#define INET_ECN_dontxmit(sk) \
do { inet_sk(sk)->tos &= ~INET_ECN_MASK; } while (0)
#define IP6_ECN_flow_init(label) do { \
(label) &= ~htonl(INET_ECN_MASK << 20); \
} while (0)
#define IP6_ECN_flow_xmit(sk, label) do { \
if (INET_ECN_is_capable(inet_sk(sk)->tos)) \
(label) |= htonl(INET_ECN_ECT_0 << 20); \
} while (0)
static inline int IP_ECN_set_ce(struct iphdr *iph)
{
u32 check = (__force u32)iph->check;
u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
/*
* After the last operation we have (in binary):
* INET_ECN_NOT_ECT => 01
* INET_ECN_ECT_1 => 10
* INET_ECN_ECT_0 => 11
* INET_ECN_CE => 00
*/
if (!(ecn & 2))
return !ecn;
/*
* The following gives us:
* INET_ECN_ECT_1 => check += htons(0xFFFD)
* INET_ECN_ECT_0 => check += htons(0xFFFE)
*/
check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
iph->check = (__force __sum16)(check + (check>=0xFFFF));
iph->tos |= INET_ECN_CE;
return 1;
}
static inline void IP_ECN_clear(struct iphdr *iph)
{
iph->tos &= ~INET_ECN_MASK;
}
static inline void ipv4_copy_dscp(struct iphdr *outer, struct iphdr *inner)
{
u32 dscp = ipv4_get_dsfield(outer) & ~INET_ECN_MASK;
ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
}
struct ipv6hdr;
static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
{
if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
return 0;
*(__be32*)iph |= htonl(INET_ECN_CE << 20);
return 1;
}
static inline void IP6_ECN_clear(struct ipv6hdr *iph)
{
*(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
}
static inline void ipv6_copy_dscp(struct ipv6hdr *outer, struct ipv6hdr *inner)
{
u32 dscp = ipv6_get_dsfield(outer) & ~INET_ECN_MASK;
ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
}
static inline int INET_ECN_set_ce(struct sk_buff *skb)
{
switch (skb->protocol) {
case __constant_htons(ETH_P_IP):
if (skb->network_header + sizeof(struct iphdr) <= skb->tail)
return IP_ECN_set_ce(ip_hdr(skb));
break;
case __constant_htons(ETH_P_IPV6):
if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail)
return IP6_ECN_set_ce(ipv6_hdr(skb));
break;
}
return 0;
}
#endif
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