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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _INET_ECN_H_
2#define _INET_ECN_H_
3
4#include <linux/ip.h>
Thomas Graf2566a502005-11-05 21:14:04 +01005#include <linux/skbuff.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -02006
7#include <net/inet_sock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008#include <net/dsfield.h>
9
10enum {
11 INET_ECN_NOT_ECT = 0,
12 INET_ECN_ECT_1 = 1,
13 INET_ECN_ECT_0 = 2,
14 INET_ECN_CE = 3,
15 INET_ECN_MASK = 3,
16};
17
18static inline int INET_ECN_is_ce(__u8 dsfield)
19{
20 return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
21}
22
23static inline int INET_ECN_is_not_ect(__u8 dsfield)
24{
25 return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
26}
27
28static inline int INET_ECN_is_capable(__u8 dsfield)
29{
30 return (dsfield & INET_ECN_ECT_0);
31}
32
33static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
34{
35 outer &= ~INET_ECN_MASK;
36 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
37 INET_ECN_ECT_0;
38 return outer;
39}
40
41#define INET_ECN_xmit(sk) do { inet_sk(sk)->tos |= INET_ECN_ECT_0; } while (0)
42#define INET_ECN_dontxmit(sk) \
43 do { inet_sk(sk)->tos &= ~INET_ECN_MASK; } while (0)
44
45#define IP6_ECN_flow_init(label) do { \
46 (label) &= ~htonl(INET_ECN_MASK << 20); \
47 } while (0)
48
49#define IP6_ECN_flow_xmit(sk, label) do { \
50 if (INET_ECN_is_capable(inet_sk(sk)->tos)) \
51 (label) |= __constant_htons(INET_ECN_ECT_0 << 4); \
52 } while (0)
53
Thomas Graf2566a502005-11-05 21:14:04 +010054static inline int IP_ECN_set_ce(struct iphdr *iph)
Linus Torvalds1da177e2005-04-16 15:20:36 -070055{
56 u32 check = iph->check;
57 u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
58
59 /*
60 * After the last operation we have (in binary):
61 * INET_ECN_NOT_ECT => 01
62 * INET_ECN_ECT_1 => 10
63 * INET_ECN_ECT_0 => 11
64 * INET_ECN_CE => 00
65 */
66 if (!(ecn & 2))
Thomas Graf2566a502005-11-05 21:14:04 +010067 return !ecn;
Linus Torvalds1da177e2005-04-16 15:20:36 -070068
69 /*
70 * The following gives us:
71 * INET_ECN_ECT_1 => check += htons(0xFFFD)
72 * INET_ECN_ECT_0 => check += htons(0xFFFE)
73 */
74 check += htons(0xFFFB) + htons(ecn);
75
76 iph->check = check + (check>=0xFFFF);
77 iph->tos |= INET_ECN_CE;
Thomas Graf2566a502005-11-05 21:14:04 +010078 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079}
80
81static inline void IP_ECN_clear(struct iphdr *iph)
82{
83 iph->tos &= ~INET_ECN_MASK;
84}
85
86static inline void ipv4_copy_dscp(struct iphdr *outer, struct iphdr *inner)
87{
88 u32 dscp = ipv4_get_dsfield(outer) & ~INET_ECN_MASK;
89 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
90}
91
92struct ipv6hdr;
93
Thomas Graf2566a502005-11-05 21:14:04 +010094static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
Linus Torvalds1da177e2005-04-16 15:20:36 -070095{
96 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
Thomas Graf2566a502005-11-05 21:14:04 +010097 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 *(u32*)iph |= htonl(INET_ECN_CE << 20);
Thomas Graf2566a502005-11-05 21:14:04 +010099 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100}
101
102static inline void IP6_ECN_clear(struct ipv6hdr *iph)
103{
104 *(u32*)iph &= ~htonl(INET_ECN_MASK << 20);
105}
106
107static inline void ipv6_copy_dscp(struct ipv6hdr *outer, struct ipv6hdr *inner)
108{
109 u32 dscp = ipv6_get_dsfield(outer) & ~INET_ECN_MASK;
110 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
111}
112
Thomas Graf2566a502005-11-05 21:14:04 +0100113static inline int INET_ECN_set_ce(struct sk_buff *skb)
114{
115 switch (skb->protocol) {
116 case __constant_htons(ETH_P_IP):
117 if (skb->nh.raw + sizeof(struct iphdr) <= skb->tail)
118 return IP_ECN_set_ce(skb->nh.iph);
119 break;
120
121 case __constant_htons(ETH_P_IPV6):
122 if (skb->nh.raw + sizeof(struct ipv6hdr) <= skb->tail)
123 return IP6_ECN_set_ce(skb->nh.ipv6h);
124 break;
125 }
126
127 return 0;
128}
129
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130#endif