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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
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
41static inline void INET_ECN_xmit(struct sock *sk)
42{
43 inet_sk(sk)->tos |= INET_ECN_ECT_0;
44 if (inet6_sk(sk) != NULL)
45 inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
46}
47
48static inline void INET_ECN_dontxmit(struct sock *sk)
49{
50 inet_sk(sk)->tos &= ~INET_ECN_MASK;
51 if (inet6_sk(sk) != NULL)
52 inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
53}
54
55#define IP6_ECN_flow_init(label) do { \
56 (label) &= ~htonl(INET_ECN_MASK << 20); \
57 } while (0)
58
59#define IP6_ECN_flow_xmit(sk, label) do { \
60 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
61 (label) |= htonl(INET_ECN_ECT_0 << 20); \
62 } while (0)
63
64static inline int IP_ECN_set_ce(struct iphdr *iph)
65{
66 u32 check = (__force u32)iph->check;
67 u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
68
69 /*
70 * After the last operation we have (in binary):
71 * INET_ECN_NOT_ECT => 01
72 * INET_ECN_ECT_1 => 10
73 * INET_ECN_ECT_0 => 11
74 * INET_ECN_CE => 00
75 */
76 if (!(ecn & 2))
77 return !ecn;
78
79 /*
80 * The following gives us:
81 * INET_ECN_ECT_1 => check += htons(0xFFFD)
82 * INET_ECN_ECT_0 => check += htons(0xFFFE)
83 */
84 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
85
86 iph->check = (__force __sum16)(check + (check>=0xFFFF));
87 iph->tos |= INET_ECN_CE;
88 return 1;
89}
90
91static inline void IP_ECN_clear(struct iphdr *iph)
92{
93 iph->tos &= ~INET_ECN_MASK;
94}
95
96static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
97{
98 dscp &= ~INET_ECN_MASK;
99 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
100}
101
102struct ipv6hdr;
103
104static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
105{
106 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
107 return 0;
108 *(__be32*)iph |= htonl(INET_ECN_CE << 20);
109 return 1;
110}
111
112static inline void IP6_ECN_clear(struct ipv6hdr *iph)
113{
114 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
115}
116
117static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
118{
119 dscp &= ~INET_ECN_MASK;
120 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
121}
122
123static inline int INET_ECN_set_ce(struct sk_buff *skb)
124{
125 switch (skb->protocol) {
126 case cpu_to_be16(ETH_P_IP):
127 if (skb->network_header + sizeof(struct iphdr) <= skb->tail)
128 return IP_ECN_set_ce(ip_hdr(skb));
129 break;
130
131 case cpu_to_be16(ETH_P_IPV6):
132 if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail)
133 return IP6_ECN_set_ce(ipv6_hdr(skb));
134 break;
135 }
136
137 return 0;
138}
139
140#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
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, (__force __wsum)from),
132 (__force __wsum)to);
133 return 1;
134}
135
136static inline void IP6_ECN_clear(struct ipv6hdr *iph)
137{
138 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
139}
140
141static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
142{
143 dscp &= ~INET_ECN_MASK;
144 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
145}
146
147static inline int INET_ECN_set_ce(struct sk_buff *skb)
148{
149 switch (skb->protocol) {
150 case cpu_to_be16(ETH_P_IP):
151 if (skb_network_header(skb) + sizeof(struct iphdr) <=
152 skb_tail_pointer(skb))
153 return IP_ECN_set_ce(ip_hdr(skb));
154 break;
155
156 case cpu_to_be16(ETH_P_IPV6):
157 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
158 skb_tail_pointer(skb))
159 return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
160 break;
161 }
162
163 return 0;
164}
165
166/*
167 * RFC 6040 4.2
168 * To decapsulate the inner header at the tunnel egress, a compliant
169 * tunnel egress MUST set the outgoing ECN field to the codepoint at the
170 * intersection of the appropriate arriving inner header (row) and outer
171 * header (column) in Figure 4
172 *
173 * +---------+------------------------------------------------+
174 * |Arriving | Arriving Outer Header |
175 * | Inner +---------+------------+------------+------------+
176 * | Header | Not-ECT | ECT(0) | ECT(1) | CE |
177 * +---------+---------+------------+------------+------------+
178 * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
179 * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE |
180 * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE |
181 * | CE | CE | CE | CE(!!!)| CE |
182 * +---------+---------+------------+------------+------------+
183 *
184 * Figure 4: New IP in IP Decapsulation Behaviour
185 *
186 * returns 0 on success
187 * 1 if something is broken and should be logged (!!! above)
188 * 2 if packet should be dropped
189 */
190static inline int INET_ECN_decapsulate(struct sk_buff *skb,
191 __u8 outer, __u8 inner)
192{
193 if (INET_ECN_is_not_ect(inner)) {
194 switch (outer & INET_ECN_MASK) {
195 case INET_ECN_NOT_ECT:
196 return 0;
197 case INET_ECN_ECT_0:
198 case INET_ECN_ECT_1:
199 return 1;
200 case INET_ECN_CE:
201 return 2;
202 }
203 }
204
205 if (INET_ECN_is_ce(outer))
206 INET_ECN_set_ce(skb);
207
208 return 0;
209}
210
211static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
212 struct sk_buff *skb)
213{
214 __u8 inner;
215
216 if (skb->protocol == htons(ETH_P_IP))
217 inner = ip_hdr(skb)->tos;
218 else if (skb->protocol == htons(ETH_P_IPV6))
219 inner = ipv6_get_dsfield(ipv6_hdr(skb));
220 else
221 return 0;
222
223 return INET_ECN_decapsulate(skb, oiph->tos, inner);
224}
225
226static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
227 struct sk_buff *skb)
228{
229 __u8 inner;
230
231 if (skb->protocol == htons(ETH_P_IP))
232 inner = ip_hdr(skb)->tos;
233 else if (skb->protocol == htons(ETH_P_IPV6))
234 inner = ipv6_get_dsfield(ipv6_hdr(skb));
235 else
236 return 0;
237
238 return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
239}
240#endif