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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
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
18extern int sysctl_tunnel_ecn_log;
19
20static inline int INET_ECN_is_ce(__u8 dsfield)
21{
22 return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
23}
24
25static inline int INET_ECN_is_not_ect(__u8 dsfield)
26{
27 return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
28}
29
30static inline int INET_ECN_is_capable(__u8 dsfield)
31{
32 return dsfield & INET_ECN_ECT_0;
33}
34
35/*
36 * RFC 3168 9.1.1
37 * The full-functionality option for ECN encapsulation is to copy the
38 * ECN codepoint of the inside header to the outside header on
39 * encapsulation if the inside header is not-ECT or ECT, and to set the
40 * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
41 * the inside header is CE.
42 */
43static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
44{
45 outer &= ~INET_ECN_MASK;
46 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
47 INET_ECN_ECT_0;
48 return outer;
49}
50
51static inline void INET_ECN_xmit(struct sock *sk)
52{
53 inet_sk(sk)->tos |= INET_ECN_ECT_0;
54 if (inet6_sk(sk) != NULL)
55 inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
56}
57
58static inline void INET_ECN_dontxmit(struct sock *sk)
59{
60 inet_sk(sk)->tos &= ~INET_ECN_MASK;
61 if (inet6_sk(sk) != NULL)
62 inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
63}
64
65#define IP6_ECN_flow_init(label) do { \
66 (label) &= ~htonl(INET_ECN_MASK << 20); \
67 } while (0)
68
69#define IP6_ECN_flow_xmit(sk, label) do { \
70 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
71 (label) |= htonl(INET_ECN_ECT_0 << 20); \
72 } while (0)
73
74static inline int IP_ECN_set_ce(struct iphdr *iph)
75{
76 u32 check = (__force u32)iph->check;
77 u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
78
79 /*
80 * After the last operation we have (in binary):
81 * INET_ECN_NOT_ECT => 01
82 * INET_ECN_ECT_1 => 10
83 * INET_ECN_ECT_0 => 11
84 * INET_ECN_CE => 00
85 */
86 if (!(ecn & 2))
87 return !ecn;
88
89 /*
90 * The following gives us:
91 * INET_ECN_ECT_1 => check += htons(0xFFFD)
92 * INET_ECN_ECT_0 => check += htons(0xFFFE)
93 */
94 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
95
96 iph->check = (__force __sum16)(check + (check>=0xFFFF));
97 iph->tos |= INET_ECN_CE;
98 return 1;
99}
100
101static inline void IP_ECN_clear(struct iphdr *iph)
102{
103 iph->tos &= ~INET_ECN_MASK;
104}
105
106static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
107{
108 dscp &= ~INET_ECN_MASK;
109 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
110}
111
112struct ipv6hdr;
113
114/* Note:
115 * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
116 * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
117 * In IPv6 case, no checksum compensates the change in IPv6 header,
118 * so we have to update skb->csum.
119 */
120static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
121{
122 __be32 from, to;
123
124 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
125 return 0;
126
127 from = *(__be32 *)iph;
128 to = from | htonl(INET_ECN_CE << 20);
129 *(__be32 *)iph = to;
130 if (skb->ip_summed == CHECKSUM_COMPLETE)
131 skb->csum = csum_add(csum_sub(skb->csum, from), to);
132 return 1;
133}
134
135static inline void IP6_ECN_clear(struct ipv6hdr *iph)
136{
137 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
138}
139
140static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
141{
142 dscp &= ~INET_ECN_MASK;
143 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
144}
145
146static inline int INET_ECN_set_ce(struct sk_buff *skb)
147{
148 switch (skb->protocol) {
149 case cpu_to_be16(ETH_P_IP):
150 if (skb_network_header(skb) + sizeof(struct iphdr) <=
151 skb_tail_pointer(skb))
152 return IP_ECN_set_ce(ip_hdr(skb));
153 break;
154
155 case cpu_to_be16(ETH_P_IPV6):
156 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
157 skb_tail_pointer(skb))
158 return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
159 break;
160 }
161
162 return 0;
163}
164
165/*
166 * RFC 6040 4.2
167 * To decapsulate the inner header at the tunnel egress, a compliant
168 * tunnel egress MUST set the outgoing ECN field to the codepoint at the
169 * intersection of the appropriate arriving inner header (row) and outer
170 * header (column) in Figure 4
171 *
172 * +---------+------------------------------------------------+
173 * |Arriving | Arriving Outer Header |
174 * | Inner +---------+------------+------------+------------+
175 * | Header | Not-ECT | ECT(0) | ECT(1) | CE |
176 * +---------+---------+------------+------------+------------+
177 * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
178 * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE |
179 * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE |
180 * | CE | CE | CE | CE(!!!)| CE |
181 * +---------+---------+------------+------------+------------+
182 *
183 * Figure 4: New IP in IP Decapsulation Behaviour
184 *
185 * returns 0 on success
186 * 1 if something is broken and should be logged (!!! above)
187 * 2 if packet should be dropped
188 */
189static inline int INET_ECN_decapsulate(struct sk_buff *skb,
190 __u8 outer, __u8 inner)
191{
192 if (INET_ECN_is_not_ect(inner)) {
193 switch (outer & INET_ECN_MASK) {
194 case INET_ECN_NOT_ECT:
195 return 0;
196 case INET_ECN_ECT_0:
197 case INET_ECN_ECT_1:
198 return 1;
199 case INET_ECN_CE:
200 return 2;
201 }
202 }
203
204 if (INET_ECN_is_ce(outer))
205 INET_ECN_set_ce(skb);
206
207 return 0;
208}
209
210static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
211 struct sk_buff *skb)
212{
213 __u8 inner;
214
215 if (skb->protocol == htons(ETH_P_IP))
216 inner = ip_hdr(skb)->tos;
217 else if (skb->protocol == htons(ETH_P_IPV6))
218 inner = ipv6_get_dsfield(ipv6_hdr(skb));
219 else
220 return 0;
221
222 return INET_ECN_decapsulate(skb, oiph->tos, inner);
223}
224
225static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
226 struct sk_buff *skb)
227{
228 __u8 inner;
229
230 if (skb->protocol == htons(ETH_P_IP))
231 inner = ip_hdr(skb)->tos;
232 else if (skb->protocol == htons(ETH_P_IPV6))
233 inner = ipv6_get_dsfield(ipv6_hdr(skb));
234 else
235 return 0;
236
237 return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
238}
239#endif
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
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
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 */
41static 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
49static 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
56static 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
72static 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
99static inline void IP_ECN_clear(struct iphdr *iph)
100{
101 iph->tos &= ~INET_ECN_MASK;
102}
103
104static 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
110struct ipv6hdr;
111
112static 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
120static inline void IP6_ECN_clear(struct ipv6hdr *iph)
121{
122 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
123}
124
125static 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
131static 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