1 #ifndef _INET_ECN_H_
2 #define _INET_ECN_H_
3
4 #include <linux/ip.h>
5 #include <linux/skbuff.h>
6
7 #include <net/inet_sock.h>
8 #include <net/dsfield.h>
9
10 enum {
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
INET_ECN_is_ce(__u8 dsfield)18 static inline int INET_ECN_is_ce(__u8 dsfield)
19 {
20 return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
21 }
22
INET_ECN_is_not_ect(__u8 dsfield)23 static inline int INET_ECN_is_not_ect(__u8 dsfield)
24 {
25 return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
26 }
27
INET_ECN_is_capable(__u8 dsfield)28 static inline int INET_ECN_is_capable(__u8 dsfield)
29 {
30 return dsfield & INET_ECN_ECT_0;
31 }
32
33 /*
34 * RFC 3168 9.1.1
35 * The full-functionality option for ECN encapsulation is to copy the
36 * ECN codepoint of the inside header to the outside header on
37 * encapsulation if the inside header is not-ECT or ECT, and to set the
38 * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
39 * the inside header is CE.
40 */
INET_ECN_encapsulate(__u8 outer,__u8 inner)41 static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
42 {
43 outer &= ~INET_ECN_MASK;
44 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
45 INET_ECN_ECT_0;
46 return outer;
47 }
48
INET_ECN_xmit(struct sock * sk)49 static inline void INET_ECN_xmit(struct sock *sk)
50 {
51 inet_sk(sk)->tos |= INET_ECN_ECT_0;
52 if (inet6_sk(sk) != NULL)
53 inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
54 }
55
INET_ECN_dontxmit(struct sock * sk)56 static inline void INET_ECN_dontxmit(struct sock *sk)
57 {
58 inet_sk(sk)->tos &= ~INET_ECN_MASK;
59 if (inet6_sk(sk) != NULL)
60 inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
61 }
62
63 #define IP6_ECN_flow_init(label) do { \
64 (label) &= ~htonl(INET_ECN_MASK << 20); \
65 } while (0)
66
67 #define IP6_ECN_flow_xmit(sk, label) do { \
68 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
69 (label) |= htonl(INET_ECN_ECT_0 << 20); \
70 } while (0)
71
IP_ECN_set_ce(struct iphdr * iph)72 static inline int IP_ECN_set_ce(struct iphdr *iph)
73 {
74 u32 check = (__force u32)iph->check;
75 u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
76
77 /*
78 * After the last operation we have (in binary):
79 * INET_ECN_NOT_ECT => 01
80 * INET_ECN_ECT_1 => 10
81 * INET_ECN_ECT_0 => 11
82 * INET_ECN_CE => 00
83 */
84 if (!(ecn & 2))
85 return !ecn;
86
87 /*
88 * The following gives us:
89 * INET_ECN_ECT_1 => check += htons(0xFFFD)
90 * INET_ECN_ECT_0 => check += htons(0xFFFE)
91 */
92 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
93
94 iph->check = (__force __sum16)(check + (check>=0xFFFF));
95 iph->tos |= INET_ECN_CE;
96 return 1;
97 }
98
IP_ECN_clear(struct iphdr * iph)99 static inline void IP_ECN_clear(struct iphdr *iph)
100 {
101 iph->tos &= ~INET_ECN_MASK;
102 }
103
ipv4_copy_dscp(unsigned int dscp,struct iphdr * inner)104 static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
105 {
106 dscp &= ~INET_ECN_MASK;
107 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
108 }
109
110 struct ipv6hdr;
111
IP6_ECN_set_ce(struct ipv6hdr * iph)112 static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
113 {
114 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
115 return 0;
116 *(__be32*)iph |= htonl(INET_ECN_CE << 20);
117 return 1;
118 }
119
IP6_ECN_clear(struct ipv6hdr * iph)120 static inline void IP6_ECN_clear(struct ipv6hdr *iph)
121 {
122 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
123 }
124
ipv6_copy_dscp(unsigned int dscp,struct ipv6hdr * inner)125 static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
126 {
127 dscp &= ~INET_ECN_MASK;
128 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
129 }
130
INET_ECN_set_ce(struct sk_buff * skb)131 static inline int INET_ECN_set_ce(struct sk_buff *skb)
132 {
133 switch (skb->protocol) {
134 case cpu_to_be16(ETH_P_IP):
135 if (skb->network_header + sizeof(struct iphdr) <= skb->tail)
136 return IP_ECN_set_ce(ip_hdr(skb));
137 break;
138
139 case cpu_to_be16(ETH_P_IPV6):
140 if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail)
141 return IP6_ECN_set_ce(ipv6_hdr(skb));
142 break;
143 }
144
145 return 0;
146 }
147
148 #endif
149