1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Multipath TCP
4 *
5 * Copyright (c) 2017 - 2019, Intel Corporation.
6 */
7
8#ifndef __NET_MPTCP_H
9#define __NET_MPTCP_H
10
11#include <linux/skbuff.h>
12#include <linux/tcp.h>
13#include <linux/types.h>
14
15struct mptcp_info;
16struct mptcp_sock;
17struct seq_file;
18
19/* MPTCP sk_buff extension data */
20struct mptcp_ext {
21 union {
22 u64 data_ack;
23 u32 data_ack32;
24 };
25 u64 data_seq;
26 u32 subflow_seq;
27 u16 data_len;
28 __sum16 csum;
29 u8 use_map:1,
30 dsn64:1,
31 data_fin:1,
32 use_ack:1,
33 ack64:1,
34 mpc_map:1,
35 frozen:1,
36 reset_transient:1;
37 u8 reset_reason:4,
38 csum_reqd:1,
39 infinite_map:1;
40};
41
42#define MPTCPOPT_HMAC_LEN 20
43#define MPTCP_RM_IDS_MAX 8
44
45struct mptcp_rm_list {
46 u8 ids[MPTCP_RM_IDS_MAX];
47 u8 nr;
48};
49
50struct mptcp_addr_info {
51 u8 id;
52 sa_family_t family;
53 __be16 port;
54 union {
55 struct in_addr addr;
56#if IS_ENABLED(CONFIG_MPTCP_IPV6)
57 struct in6_addr addr6;
58#endif
59 };
60};
61
62struct mptcp_out_options {
63#if IS_ENABLED(CONFIG_MPTCP)
64 u16 suboptions;
65 struct mptcp_rm_list rm_list;
66 u8 join_id;
67 u8 backup;
68 u8 reset_reason:4,
69 reset_transient:1,
70 csum_reqd:1,
71 allow_join_id0:1;
72 union {
73 struct {
74 u64 sndr_key;
75 u64 rcvr_key;
76 u64 data_seq;
77 u32 subflow_seq;
78 u16 data_len;
79 __sum16 csum;
80 };
81 struct {
82 struct mptcp_addr_info addr;
83 u64 ahmac;
84 };
85 struct {
86 struct mptcp_ext ext_copy;
87 u64 fail_seq;
88 };
89 struct {
90 u32 nonce;
91 u32 token;
92 u64 thmac;
93 u8 hmac[MPTCPOPT_HMAC_LEN];
94 };
95 };
96#endif
97};
98
99#ifdef CONFIG_MPTCP
100extern struct request_sock_ops mptcp_subflow_request_sock_ops;
101
102void mptcp_init(void);
103
104static inline bool sk_is_mptcp(const struct sock *sk)
105{
106 return tcp_sk(sk)->is_mptcp;
107}
108
109static inline bool rsk_is_mptcp(const struct request_sock *req)
110{
111 return tcp_rsk(req)->is_mptcp;
112}
113
114static inline bool rsk_drop_req(const struct request_sock *req)
115{
116 return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
117}
118
119void mptcp_space(const struct sock *ssk, int *space, int *full_space);
120bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
121 unsigned int *size, struct mptcp_out_options *opts);
122bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
123 struct mptcp_out_options *opts);
124bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
125 unsigned int *size, unsigned int remaining,
126 struct mptcp_out_options *opts);
127bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
128
129void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
130 struct mptcp_out_options *opts);
131
132void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
133
134/* move the skb extension owership, with the assumption that 'to' is
135 * newly allocated
136 */
137static inline void mptcp_skb_ext_move(struct sk_buff *to,
138 struct sk_buff *from)
139{
140 if (!skb_ext_exist(from, SKB_EXT_MPTCP))
141 return;
142
143 if (WARN_ON_ONCE(to->active_extensions))
144 skb_ext_put(to);
145
146 to->active_extensions = from->active_extensions;
147 to->extensions = from->extensions;
148 from->active_extensions = 0;
149}
150
151static inline void mptcp_skb_ext_copy(struct sk_buff *to,
152 struct sk_buff *from)
153{
154 struct mptcp_ext *from_ext;
155
156 from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
157 if (!from_ext)
158 return;
159
160 from_ext->frozen = 1;
161 skb_ext_copy(to, from);
162}
163
164static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
165 const struct mptcp_ext *from_ext)
166{
167 /* MPTCP always clears the ext when adding it to the skb, so
168 * holes do not bother us here
169 */
170 return !from_ext ||
171 (to_ext && from_ext &&
172 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
173}
174
175/* check if skbs can be collapsed.
176 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
177 * mapping, or if the extension of @to is the same as @from.
178 * Collapsing is not possible if @to lacks an extension, but @from carries one.
179 */
180static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
181 const struct sk_buff *from)
182{
183 return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
184 skb_ext_find(from, SKB_EXT_MPTCP));
185}
186
187void mptcp_seq_show(struct seq_file *seq);
188int mptcp_subflow_init_cookie_req(struct request_sock *req,
189 const struct sock *sk_listener,
190 struct sk_buff *skb);
191
192__be32 mptcp_get_reset_option(const struct sk_buff *skb);
193
194static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
195{
196 if (skb_ext_exist(skb, SKB_EXT_MPTCP))
197 return mptcp_get_reset_option(skb);
198
199 return htonl(0u);
200}
201#else
202
203static inline void mptcp_init(void)
204{
205}
206
207static inline bool sk_is_mptcp(const struct sock *sk)
208{
209 return false;
210}
211
212static inline bool rsk_is_mptcp(const struct request_sock *req)
213{
214 return false;
215}
216
217static inline bool rsk_drop_req(const struct request_sock *req)
218{
219 return false;
220}
221
222static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
223 unsigned int *size,
224 struct mptcp_out_options *opts)
225{
226 return false;
227}
228
229static inline bool mptcp_synack_options(const struct request_sock *req,
230 unsigned int *size,
231 struct mptcp_out_options *opts)
232{
233 return false;
234}
235
236static inline bool mptcp_established_options(struct sock *sk,
237 struct sk_buff *skb,
238 unsigned int *size,
239 unsigned int remaining,
240 struct mptcp_out_options *opts)
241{
242 return false;
243}
244
245static inline bool mptcp_incoming_options(struct sock *sk,
246 struct sk_buff *skb)
247{
248 return true;
249}
250
251static inline void mptcp_skb_ext_move(struct sk_buff *to,
252 const struct sk_buff *from)
253{
254}
255
256static inline void mptcp_skb_ext_copy(struct sk_buff *to,
257 struct sk_buff *from)
258{
259}
260
261static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
262 const struct sk_buff *from)
263{
264 return true;
265}
266
267static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
268static inline void mptcp_seq_show(struct seq_file *seq) { }
269
270static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
271 const struct sock *sk_listener,
272 struct sk_buff *skb)
273{
274 return 0; /* TCP fallback */
275}
276
277static inline __be32 mptcp_reset_option(const struct sk_buff *skb) { return htonl(0u); }
278#endif /* CONFIG_MPTCP */
279
280#if IS_ENABLED(CONFIG_MPTCP_IPV6)
281int mptcpv6_init(void);
282void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
283#elif IS_ENABLED(CONFIG_IPV6)
284static inline int mptcpv6_init(void) { return 0; }
285static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
286#endif
287
288#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
289struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
290#else
291static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
292#endif
293
294#if !IS_ENABLED(CONFIG_MPTCP)
295struct mptcp_sock { };
296#endif
297
298#endif /* __NET_MPTCP_H */
299

source code of linux/include/net/mptcp.h