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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 | ||
11 | enum { | |
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 | 19 | extern int sysctl_tunnel_ecn_log; |
20 | ||
1da177e4 LT |
21 | static inline int INET_ECN_is_ce(__u8 dsfield) |
22 | { | |
23 | return (dsfield & INET_ECN_MASK) == INET_ECN_CE; | |
24 | } | |
25 | ||
26 | static inline int INET_ECN_is_not_ect(__u8 dsfield) | |
27 | { | |
28 | return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT; | |
29 | } | |
30 | ||
31 | static 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 |
44 | static 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 |
52 | static 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 | ||
59 | static 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 | 75 | static 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 | ||
102 | static inline void IP_ECN_clear(struct iphdr *iph) | |
103 | { | |
104 | iph->tos &= ~INET_ECN_MASK; | |
105 | } | |
106 | ||
29bb43b4 | 107 | static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner) |
1da177e4 | 108 | { |
29bb43b4 | 109 | dscp &= ~INET_ECN_MASK; |
1da177e4 LT |
110 | ipv4_change_dsfield(inner, INET_ECN_MASK, dscp); |
111 | } | |
112 | ||
113 | struct ipv6hdr; | |
114 | ||
34ae6a1a ED |
115 | /* Note: |
116 | * IP_ECN_set_ce() has to tweak IPV4 checksum when setting CE, | |
117 | * meaning both changes have no effect on skb->csum if/when CHECKSUM_COMPLETE | |
118 | * In IPv6 case, no checksum compensates the change in IPv6 header, | |
119 | * so we have to update skb->csum. | |
120 | */ | |
121 | static inline int IP6_ECN_set_ce(struct sk_buff *skb, struct ipv6hdr *iph) | |
1da177e4 | 122 | { |
34ae6a1a ED |
123 | __be32 from, to; |
124 | ||
1da177e4 | 125 | if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph))) |
2566a509 | 126 | return 0; |
34ae6a1a ED |
127 | |
128 | from = *(__be32 *)iph; | |
129 | to = from | htonl(INET_ECN_CE << 20); | |
130 | *(__be32 *)iph = to; | |
131 | if (skb->ip_summed == CHECKSUM_COMPLETE) | |
c15c0ab1 JB |
132 | skb->csum = csum_add(csum_sub(skb->csum, (__force __wsum)from), |
133 | (__force __wsum)to); | |
2566a509 | 134 | return 1; |
1da177e4 LT |
135 | } |
136 | ||
29bb43b4 | 137 | static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner) |
1da177e4 | 138 | { |
29bb43b4 | 139 | dscp &= ~INET_ECN_MASK; |
1da177e4 LT |
140 | ipv6_change_dsfield(inner, INET_ECN_MASK, dscp); |
141 | } | |
142 | ||
2566a509 TG |
143 | static inline int INET_ECN_set_ce(struct sk_buff *skb) |
144 | { | |
145 | switch (skb->protocol) { | |
f3a7c66b | 146 | case cpu_to_be16(ETH_P_IP): |
ced14f68 SH |
147 | if (skb_network_header(skb) + sizeof(struct iphdr) <= |
148 | skb_tail_pointer(skb)) | |
eddc9ec5 | 149 | return IP_ECN_set_ce(ip_hdr(skb)); |
2566a509 TG |
150 | break; |
151 | ||
f3a7c66b | 152 | case cpu_to_be16(ETH_P_IPV6): |
ced14f68 SH |
153 | if (skb_network_header(skb) + sizeof(struct ipv6hdr) <= |
154 | skb_tail_pointer(skb)) | |
34ae6a1a | 155 | return IP6_ECN_set_ce(skb, ipv6_hdr(skb)); |
2566a509 TG |
156 | break; |
157 | } | |
158 | ||
159 | return 0; | |
160 | } | |
161 | ||
eccc1bb8 | 162 | /* |
d28071d1 | 163 | * RFC 6040 4.2 |
eccc1bb8 | 164 | * To decapsulate the inner header at the tunnel egress, a compliant |
165 | * tunnel egress MUST set the outgoing ECN field to the codepoint at the | |
166 | * intersection of the appropriate arriving inner header (row) and outer | |
167 | * header (column) in Figure 4 | |
168 | * | |
169 | * +---------+------------------------------------------------+ | |
170 | * |Arriving | Arriving Outer Header | | |
171 | * | Inner +---------+------------+------------+------------+ | |
172 | * | Header | Not-ECT | ECT(0) | ECT(1) | CE | | |
173 | * +---------+---------+------------+------------+------------+ | |
174 | * | Not-ECT | Not-ECT |Not-ECT(!!!)|Not-ECT(!!!)| <drop>(!!!)| | |
175 | * | ECT(0) | ECT(0) | ECT(0) | ECT(1) | CE | | |
176 | * | ECT(1) | ECT(1) | ECT(1) (!) | ECT(1) | CE | | |
177 | * | CE | CE | CE | CE(!!!)| CE | | |
178 | * +---------+---------+------------+------------+------------+ | |
179 | * | |
180 | * Figure 4: New IP in IP Decapsulation Behaviour | |
181 | * | |
182 | * returns 0 on success | |
183 | * 1 if something is broken and should be logged (!!! above) | |
184 | * 2 if packet should be dropped | |
185 | */ | |
186 | static inline int INET_ECN_decapsulate(struct sk_buff *skb, | |
187 | __u8 outer, __u8 inner) | |
188 | { | |
189 | if (INET_ECN_is_not_ect(inner)) { | |
190 | switch (outer & INET_ECN_MASK) { | |
191 | case INET_ECN_NOT_ECT: | |
192 | return 0; | |
193 | case INET_ECN_ECT_0: | |
194 | case INET_ECN_ECT_1: | |
195 | return 1; | |
196 | case INET_ECN_CE: | |
197 | return 2; | |
198 | } | |
199 | } | |
200 | ||
201 | if (INET_ECN_is_ce(outer)) | |
202 | INET_ECN_set_ce(skb); | |
203 | ||
204 | return 0; | |
205 | } | |
206 | ||
207 | static inline int IP_ECN_decapsulate(const struct iphdr *oiph, | |
208 | struct sk_buff *skb) | |
209 | { | |
210 | __u8 inner; | |
211 | ||
212 | if (skb->protocol == htons(ETH_P_IP)) | |
213 | inner = ip_hdr(skb)->tos; | |
214 | else if (skb->protocol == htons(ETH_P_IPV6)) | |
215 | inner = ipv6_get_dsfield(ipv6_hdr(skb)); | |
216 | else | |
217 | return 0; | |
218 | ||
219 | return INET_ECN_decapsulate(skb, oiph->tos, inner); | |
220 | } | |
221 | ||
222 | static inline int IP6_ECN_decapsulate(const struct ipv6hdr *oipv6h, | |
223 | struct sk_buff *skb) | |
224 | { | |
225 | __u8 inner; | |
226 | ||
227 | if (skb->protocol == htons(ETH_P_IP)) | |
228 | inner = ip_hdr(skb)->tos; | |
229 | else if (skb->protocol == htons(ETH_P_IPV6)) | |
230 | inner = ipv6_get_dsfield(ipv6_hdr(skb)); | |
231 | else | |
232 | return 0; | |
233 | ||
234 | return INET_ECN_decapsulate(skb, ipv6_get_dsfield(oipv6h), inner); | |
235 | } | |
1da177e4 | 236 | #endif |