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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
114static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
115{
116 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
117 return 0;
118 *(__be32*)iph |= htonl(INET_ECN_CE << 20);
119 return 1;
120}
121
122static inline void IP6_ECN_clear(struct ipv6hdr *iph)
123{
124 *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
125}
126
127static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
128{
129 dscp &= ~INET_ECN_MASK;
130 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
131}
132
133static inline int INET_ECN_set_ce(struct sk_buff *skb)
134{
135 switch (skb->protocol) {
136 case cpu_to_be16(ETH_P_IP):
137 if (skb_network_header(skb) + sizeof(struct iphdr) <=
138 skb_tail_pointer(skb))
139 return IP_ECN_set_ce(ip_hdr(skb));
140 break;
141
142 case cpu_to_be16(ETH_P_IPV6):
143 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
144 skb_tail_pointer(skb))
145 return IP6_ECN_set_ce(ipv6_hdr(skb));
146 break;
147 }
148
149 return 0;
150}
151
152/*
153 * RFC 6080 4.2
154 * To decapsulate the inner header at the tunnel egress, a compliant
155 * tunnel egress MUST set the outgoing ECN field to the codepoint at the
156 * intersection of the appropriate arriving inner header (row) and outer
157 * header (column) in Figure 4
158 *
159 * +---------+------------------------------------------------+
160 * |Arriving | Arriving Outer Header |
161 * | Inner +---------+------------+------------+------------+
162 * | Header | Not-ECT | ECT(0) | ECT(1) | CE |
163 * +---------+---------+------------+------------+------------+
164 * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
165 * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE |
166 * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE |
167 * | CE | CE | CE | CE(!!!)| CE |
168 * +---------+---------+------------+------------+------------+
169 *
170 * Figure 4: New IP in IP Decapsulation Behaviour
171 *
172 * returns 0 on success
173 * 1 if something is broken and should be logged (!!! above)
174 * 2 if packet should be dropped
175 */
176static inline int INET_ECN_decapsulate(struct sk_buff *skb,
177 __u8 outer, __u8 inner)
178{
179 if (INET_ECN_is_not_ect(inner)) {
180 switch (outer & INET_ECN_MASK) {
181 case INET_ECN_NOT_ECT:
182 return 0;
183 case INET_ECN_ECT_0:
184 case INET_ECN_ECT_1:
185 return 1;
186 case INET_ECN_CE:
187 return 2;
188 }
189 }
190
191 if (INET_ECN_is_ce(outer))
192 INET_ECN_set_ce(skb);
193
194 return 0;
195}
196
197static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
198 struct sk_buff *skb)
199{
200 __u8 inner;
201
202 if (skb->protocol == htons(ETH_P_IP))
203 inner = ip_hdr(skb)->tos;
204 else if (skb->protocol == htons(ETH_P_IPV6))
205 inner = ipv6_get_dsfield(ipv6_hdr(skb));
206 else
207 return 0;
208
209 return INET_ECN_decapsulate(skb, oiph->tos, inner);
210}
211
212static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
213 struct sk_buff *skb)
214{
215 __u8 inner;
216
217 if (skb->protocol == htons(ETH_P_IP))
218 inner = ip_hdr(skb)->tos;
219 else if (skb->protocol == htons(ETH_P_IPV6))
220 inner = ipv6_get_dsfield(ipv6_hdr(skb));
221 else
222 return 0;
223
224 return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
225}
226#endif
1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _INET_ECN_H_
3#define _INET_ECN_H_
4
5#include <linux/ip.h>
6#include <linux/skbuff.h>
7#include <linux/if_vlan.h>
8
9#include <net/inet_sock.h>
10#include <net/dsfield.h>
11
12enum {
13 INET_ECN_NOT_ECT = 0,
14 INET_ECN_ECT_1 = 1,
15 INET_ECN_ECT_0 = 2,
16 INET_ECN_CE = 3,
17 INET_ECN_MASK = 3,
18};
19
20extern int sysctl_tunnel_ecn_log;
21
22static inline int INET_ECN_is_ce(__u8 dsfield)
23{
24 return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
25}
26
27static inline int INET_ECN_is_not_ect(__u8 dsfield)
28{
29 return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
30}
31
32static inline int INET_ECN_is_capable(__u8 dsfield)
33{
34 return dsfield & INET_ECN_ECT_0;
35}
36
37/*
38 * RFC 3168 9.1.1
39 * The full-functionality option for ECN encapsulation is to copy the
40 * ECN codepoint of the inside header to the outside header on
41 * encapsulation if the inside header is not-ECT or ECT, and to set the
42 * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
43 * the inside header is CE.
44 */
45static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
46{
47 outer &= ~INET_ECN_MASK;
48 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
49 INET_ECN_ECT_0;
50 return outer;
51}
52
53static inline void INET_ECN_xmit(struct sock *sk)
54{
55 inet_sk(sk)->tos |= INET_ECN_ECT_0;
56 if (inet6_sk(sk) != NULL)
57 inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
58}
59
60static inline void INET_ECN_dontxmit(struct sock *sk)
61{
62 inet_sk(sk)->tos &= ~INET_ECN_MASK;
63 if (inet6_sk(sk) != NULL)
64 inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
65}
66
67#define IP6_ECN_flow_init(label) do { \
68 (label) &= ~htonl(INET_ECN_MASK << 20); \
69 } while (0)
70
71#define IP6_ECN_flow_xmit(sk, label) do { \
72 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
73 (label) |= htonl(INET_ECN_ECT_0 << 20); \
74 } while (0)
75
76static inline int IP_ECN_set_ce(struct iphdr *iph)
77{
78 u32 check = (__force u32)iph->check;
79 u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
80
81 /*
82 * After the last operation we have (in binary):
83 * INET_ECN_NOT_ECT => 01
84 * INET_ECN_ECT_1 => 10
85 * INET_ECN_ECT_0 => 11
86 * INET_ECN_CE => 00
87 */
88 if (!(ecn & 2))
89 return !ecn;
90
91 /*
92 * The following gives us:
93 * INET_ECN_ECT_1 => check += htons(0xFFFD)
94 * INET_ECN_ECT_0 => check += htons(0xFFFE)
95 */
96 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
97
98 iph->check = (__force __sum16)(check + (check>=0xFFFF));
99 iph->tos |= INET_ECN_CE;
100 return 1;
101}
102
103static inline int IP_ECN_set_ect1(struct iphdr *iph)
104{
105 u32 check = (__force u32)iph->check;
106
107 if ((iph->tos & INET_ECN_MASK) != INET_ECN_ECT_0)
108 return 0;
109
110 check += (__force u16)htons(0x100);
111
112 iph->check = (__force __sum16)(check + (check>=0xFFFF));
113 iph->tos ^= INET_ECN_MASK;
114 return 1;
115}
116
117static inline void IP_ECN_clear(struct iphdr *iph)
118{
119 iph->tos &= ~INET_ECN_MASK;
120}
121
122static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
123{
124 dscp &= ~INET_ECN_MASK;
125 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
126}
127
128struct ipv6hdr;
129
130/* Note:
131 * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
132 * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
133 * In IPv6 case, no checksum compensates the change in IPv6 header,
134 * so we have to update skb->csum.
135 */
136static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
137{
138 __be32 from, to;
139
140 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
141 return 0;
142
143 from = *(__be32 *)iph;
144 to = from | htonl(INET_ECN_CE << 20);
145 *(__be32 *)iph = to;
146 if (skb->ip_summed == CHECKSUM_COMPLETE)
147 skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
148 (__force __wsum)to);
149 return 1;
150}
151
152static inline int IP6_ECN_set_ect1(struct sk_buff *skb, struct ipv6hdr *iph)
153{
154 __be32 from, to;
155
156 if ((ipv6_get_dsfield(iph) & INET_ECN_MASK) != INET_ECN_ECT_0)
157 return 0;
158
159 from = *(__be32 *)iph;
160 to = from ^ htonl(INET_ECN_MASK << 20);
161 *(__be32 *)iph = to;
162 if (skb->ip_summed == CHECKSUM_COMPLETE)
163 skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
164 (__force __wsum)to);
165 return 1;
166}
167
168static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
169{
170 dscp &= ~INET_ECN_MASK;
171 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
172}
173
174static inline int INET_ECN_set_ce(struct sk_buff *skb)
175{
176 switch (skb_protocol(skb, true)) {
177 case cpu_to_be16(ETH_P_IP):
178 if (skb_network_header(skb) + sizeof(struct iphdr) <=
179 skb_tail_pointer(skb))
180 return IP_ECN_set_ce(ip_hdr(skb));
181 break;
182
183 case cpu_to_be16(ETH_P_IPV6):
184 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
185 skb_tail_pointer(skb))
186 return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
187 break;
188 }
189
190 return 0;
191}
192
193static inline int INET_ECN_set_ect1(struct sk_buff *skb)
194{
195 switch (skb_protocol(skb, true)) {
196 case cpu_to_be16(ETH_P_IP):
197 if (skb_network_header(skb) + sizeof(struct iphdr) <=
198 skb_tail_pointer(skb))
199 return IP_ECN_set_ect1(ip_hdr(skb));
200 break;
201
202 case cpu_to_be16(ETH_P_IPV6):
203 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
204 skb_tail_pointer(skb))
205 return IP6_ECN_set_ect1(skb, ipv6_hdr(skb));
206 break;
207 }
208
209 return 0;
210}
211
212/*
213 * RFC 6040 4.2
214 * To decapsulate the inner header at the tunnel egress, a compliant
215 * tunnel egress MUST set the outgoing ECN field to the codepoint at the
216 * intersection of the appropriate arriving inner header (row) and outer
217 * header (column) in Figure 4
218 *
219 * +---------+------------------------------------------------+
220 * |Arriving | Arriving Outer Header |
221 * | Inner +---------+------------+------------+------------+
222 * | Header | Not-ECT | ECT(0) | ECT(1) | CE |
223 * +---------+---------+------------+------------+------------+
224 * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
225 * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE |
226 * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE |
227 * | CE | CE | CE | CE(!!!)| CE |
228 * +---------+---------+------------+------------+------------+
229 *
230 * Figure 4: New IP in IP Decapsulation Behaviour
231 *
232 * returns 0 on success
233 * 1 if something is broken and should be logged (!!! above)
234 * 2 if packet should be dropped
235 */
236static inline int __INET_ECN_decapsulate(__u8 outer, __u8 inner, bool *set_ce)
237{
238 if (INET_ECN_is_not_ect(inner)) {
239 switch (outer & INET_ECN_MASK) {
240 case INET_ECN_NOT_ECT:
241 return 0;
242 case INET_ECN_ECT_0:
243 case INET_ECN_ECT_1:
244 return 1;
245 case INET_ECN_CE:
246 return 2;
247 }
248 }
249
250 *set_ce = INET_ECN_is_ce(outer);
251 return 0;
252}
253
254static inline int INET_ECN_decapsulate(struct sk_buff *skb,
255 __u8 outer, __u8 inner)
256{
257 bool set_ce = false;
258 int rc;
259
260 rc = __INET_ECN_decapsulate(outer, inner, &set_ce);
261 if (!rc) {
262 if (set_ce)
263 INET_ECN_set_ce(skb);
264 else if ((outer & INET_ECN_MASK) == INET_ECN_ECT_1)
265 INET_ECN_set_ect1(skb);
266 }
267
268 return rc;
269}
270
271static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
272 struct sk_buff *skb)
273{
274 __u8 inner;
275
276 switch (skb_protocol(skb, true)) {
277 case htons(ETH_P_IP):
278 inner = ip_hdr(skb)->tos;
279 break;
280 case htons(ETH_P_IPV6):
281 inner = ipv6_get_dsfield(ipv6_hdr(skb));
282 break;
283 default:
284 return 0;
285 }
286
287 return INET_ECN_decapsulate(skb, oiph->tos, inner);
288}
289
290static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
291 struct sk_buff *skb)
292{
293 __u8 inner;
294
295 switch (skb_protocol(skb, true)) {
296 case htons(ETH_P_IP):
297 inner = ip_hdr(skb)->tos;
298 break;
299 case htons(ETH_P_IPV6):
300 inner = ipv6_get_dsfield(ipv6_hdr(skb));
301 break;
302 default:
303 return 0;
304 }
305
306 return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
307}
308#endif