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Merge tag 'io_uring-5.7-2020-05-22' of git://git.kernel.dk/linux-block
[thirdparty/linux.git] / include / net / inet_ecn.h
CommitLineData
b2441318 1/* SPDX-License-Identifier: GPL-2.0 */
1da177e4
LT
2#ifndef _INET_ECN_H_
3#define _INET_ECN_H_
4
5#include <linux/ip.h>
2566a509 6#include <linux/skbuff.h>
14c85021
ACM
7
8#include <net/inet_sock.h>
1da177e4
LT
9#include <net/dsfield.h>
10
11enum {
12 INET_ECN_NOT_ECT = 0,
13 INET_ECN_ECT_1 = 1,
14 INET_ECN_ECT_0 = 2,
15 INET_ECN_CE = 3,
16 INET_ECN_MASK = 3,
17};
18
eccc1bb8 19extern int sysctl_tunnel_ecn_log;
20
1da177e4
LT
21static inline int INET_ECN_is_ce(__u8 dsfield)
22{
23 return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
24}
25
26static inline int INET_ECN_is_not_ect(__u8 dsfield)
27{
28 return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
29}
30
31static inline int INET_ECN_is_capable(__u8 dsfield)
32{
a02cec21 33 return dsfield & INET_ECN_ECT_0;
1da177e4
LT
34}
35
b5d9c9c2
ED
36/*
37 * RFC 3168 9.1.1
38 * The full-functionality option for ECN encapsulation is to copy the
39 * ECN codepoint of the inside header to the outside header on
40 * encapsulation if the inside header is not-ECT or ECT, and to set the
41 * ECN codepoint of the outside header to ECT(0) if the ECN codepoint of
42 * the inside header is CE.
43 */
1da177e4
LT
44static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
45{
46 outer &= ~INET_ECN_MASK;
47 outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
48 INET_ECN_ECT_0;
49 return outer;
50}
51
ca067070
SG
52static inline void INET_ECN_xmit(struct sock *sk)
53{
54 inet_sk(sk)->tos |= INET_ECN_ECT_0;
55 if (inet6_sk(sk) != NULL)
56 inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
57}
58
59static inline void INET_ECN_dontxmit(struct sock *sk)
60{
61 inet_sk(sk)->tos &= ~INET_ECN_MASK;
62 if (inet6_sk(sk) != NULL)
63 inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
64}
1da177e4
LT
65
66#define IP6_ECN_flow_init(label) do { \
67 (label) &= ~htonl(INET_ECN_MASK << 20); \
68 } while (0)
69
70#define IP6_ECN_flow_xmit(sk, label) do { \
e9df2e8f 71 if (INET_ECN_is_capable(inet6_sk(sk)->tclass)) \
95026cd2 72 (label) |= htonl(INET_ECN_ECT_0 << 20); \
1da177e4
LT
73 } while (0)
74
2566a509 75static inline int IP_ECN_set_ce(struct iphdr *iph)
1da177e4 76{
5c78f275 77 u32 check = (__force u32)iph->check;
1da177e4
LT
78 u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
79
80 /*
81 * After the last operation we have (in binary):
82 * INET_ECN_NOT_ECT => 01
83 * INET_ECN_ECT_1 => 10
84 * INET_ECN_ECT_0 => 11
85 * INET_ECN_CE => 00
86 */
87 if (!(ecn & 2))
2566a509 88 return !ecn;
1da177e4
LT
89
90 /*
91 * The following gives us:
92 * INET_ECN_ECT_1 => check += htons(0xFFFD)
93 * INET_ECN_ECT_0 => check += htons(0xFFFE)
94 */
5c78f275 95 check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
1da177e4 96
5c78f275 97 iph->check = (__force __sum16)(check + (check>=0xFFFF));
1da177e4 98 iph->tos |= INET_ECN_CE;
2566a509 99 return 1;
1da177e4
LT
100}
101
b7237487
THJ
102static inline int IP_ECN_set_ect1(struct iphdr *iph)
103{
104 u32 check = (__force u32)iph->check;
105
106 if ((iph->tos & INET_ECN_MASK) != INET_ECN_ECT_0)
107 return 0;
108
109 check += (__force u16)htons(0x100);
110
111 iph->check = (__force __sum16)(check + (check>=0xFFFF));
112 iph->tos ^= INET_ECN_MASK;
113 return 1;
114}
115
1da177e4
LT
116static inline void IP_ECN_clear(struct iphdr *iph)
117{
118 iph->tos &= ~INET_ECN_MASK;
119}
120
29bb43b4 121static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
1da177e4 122{
29bb43b4 123 dscp &= ~INET_ECN_MASK;
1da177e4
LT
124 ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
125}
126
127struct ipv6hdr;
128
34ae6a1a
ED
129/* Note:
130 * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE,
131 * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE
132 * In IPv6 case, no checksum compensates the change in IPv6 header,
133 * so we have to update skb->csum.
134 */
135static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph)
1da177e4 136{
34ae6a1a
ED
137 __be32 from, to;
138
1da177e4 139 if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
2566a509 140 return 0;
34ae6a1a
ED
141
142 from = *(__be32 *)iph;
143 to = from | htonl(INET_ECN_CE << 20);
144 *(__be32 *)iph = to;
145 if (skb->ip_summed == CHECKSUM_COMPLETE)
c15c0ab1
JB
146 skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
147 (__force __wsum)to);
2566a509 148 return 1;
1da177e4
LT
149}
150
b7237487
THJ
151static inline int IP6_ECN_set_ect1(struct sk_buff *skb, struct ipv6hdr *iph)
152{
153 __be32 from, to;
154
155 if ((ipv6_get_dsfield(iph) & INET_ECN_MASK) != INET_ECN_ECT_0)
156 return 0;
157
158 from = *(__be32 *)iph;
159 to = from ^ htonl(INET_ECN_MASK << 20);
160 *(__be32 *)iph = to;
161 if (skb->ip_summed == CHECKSUM_COMPLETE)
162 skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from),
163 (__force __wsum)to);
164 return 1;
165}
166
29bb43b4 167static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
1da177e4 168{
29bb43b4 169 dscp &= ~INET_ECN_MASK;
1da177e4
LT
170 ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
171}
172
2566a509
TG
173static inline int INET_ECN_set_ce(struct sk_buff *skb)
174{
175 switch (skb->protocol) {
f3a7c66b 176 case cpu_to_be16(ETH_P_IP):
ced14f68
SH
177 if (skb_network_header(skb) + sizeof(struct iphdr) <=
178 skb_tail_pointer(skb))
eddc9ec5 179 return IP_ECN_set_ce(ip_hdr(skb));
2566a509
TG
180 break;
181
f3a7c66b 182 case cpu_to_be16(ETH_P_IPV6):
ced14f68
SH
183 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
184 skb_tail_pointer(skb))
34ae6a1a 185 return IP6_ECN_set_ce(skb, ipv6_hdr(skb));
2566a509
TG
186 break;
187 }
188
189 return 0;
190}
191
b7237487
THJ
192static inline int INET_ECN_set_ect1(struct sk_buff *skb)
193{
194 switch (skb->protocol) {
195 case cpu_to_be16(ETH_P_IP):
196 if (skb_network_header(skb) + sizeof(struct iphdr) <=
197 skb_tail_pointer(skb))
198 return IP_ECN_set_ect1(ip_hdr(skb));
199 break;
200
201 case cpu_to_be16(ETH_P_IPV6):
202 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
203 skb_tail_pointer(skb))
204 return IP6_ECN_set_ect1(skb, ipv6_hdr(skb));
205 break;
206 }
207
208 return 0;
209}
210
eccc1bb8 211/*
d28071d1 212 * RFC 6040 4.2
eccc1bb8 213 * To decapsulate the inner header at the tunnel egress, a compliant
214 * tunnel egress MUST set the outgoing ECN field to the codepoint at the
215 * intersection of the appropriate arriving inner header (row) and outer
216 * header (column) in Figure 4
217 *
218 * +---------+------------------------------------------------+
219 * |Arriving | Arriving Outer Header |
220 * | Inner +---------+------------+------------+------------+
221 * | Header | Not-ECT | ECT(0) | ECT(1) | CE |
222 * +---------+---------+------------+------------+------------+
223 * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)|
224 * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE |
225 * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE |
226 * | CE | CE | CE | CE(!!!)| CE |
227 * +---------+---------+------------+------------+------------+
228 *
229 * Figure 4: New IP in IP Decapsulation Behaviour
230 *
231 * returns 0 on success
232 * 1 if something is broken and should be logged (!!! above)
233 * 2 if packet should be dropped
234 */
28e45033 235static inline int __INET_ECN_decapsulate(__u8 outer, __u8 inner, bool *set_ce)
eccc1bb8 236{
237 if (INET_ECN_is_not_ect(inner)) {
238 switch (outer & INET_ECN_MASK) {
239 case INET_ECN_NOT_ECT:
240 return 0;
241 case INET_ECN_ECT_0:
242 case INET_ECN_ECT_1:
243 return 1;
244 case INET_ECN_CE:
245 return 2;
246 }
247 }
248
28e45033
IS
249 *set_ce = INET_ECN_is_ce(outer);
250 return 0;
251}
252
253static inline int INET_ECN_decapsulate(struct sk_buff *skb,
254 __u8 outer, __u8 inner)
255{
256 bool set_ce = false;
257 int rc;
258
259 rc = __INET_ECN_decapsulate(outer, inner, &set_ce);
b7237487
THJ
260 if (!rc) {
261 if (set_ce)
262 INET_ECN_set_ce(skb);
263 else if ((outer & INET_ECN_MASK) == INET_ECN_ECT_1)
264 INET_ECN_set_ect1(skb);
265 }
eccc1bb8 266
28e45033 267 return rc;
eccc1bb8 268}
269
270static inline int IP_ECN_decapsulate(const struct iphdr *oiph,
271 struct sk_buff *skb)
272{
273 __u8 inner;
274
275 if (skb->protocol == htons(ETH_P_IP))
276 inner = ip_hdr(skb)->tos;
277 else if (skb->protocol == htons(ETH_P_IPV6))
278 inner = ipv6_get_dsfield(ipv6_hdr(skb));
279 else
280 return 0;
281
282 return INET_ECN_decapsulate(skb, oiph->tos, inner);
283}
284
285static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h,
286 struct sk_buff *skb)
287{
288 __u8 inner;
289
290 if (skb->protocol == htons(ETH_P_IP))
291 inner = ip_hdr(skb)->tos;
292 else if (skb->protocol == htons(ETH_P_IPV6))
293 inner = ipv6_get_dsfield(ipv6_hdr(skb));
294 else
295 return 0;
296
297 return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner);
298}
1da177e4 299#endif