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 mptcp_pm_addr_entry;
18struct seq_file;
19
20/* MPTCP sk_buff extension data */
21struct mptcp_ext {
22 union {
23 u64 data_ack;
24 u32 data_ack32;
25 };
26 u64 data_seq;
27 u32 subflow_seq;
28 u16 data_len;
29 __sum16 csum;
30 u8 use_map:1,
31 dsn64:1,
32 data_fin:1,
33 use_ack:1,
34 ack64:1,
35 mpc_map:1,
36 frozen:1,
37 reset_transient:1;
38 u8 reset_reason:4,
39 csum_reqd:1,
40 infinite_map:1;
41};
42
43#define MPTCPOPT_HMAC_LEN 20
44#define MPTCP_RM_IDS_MAX 8
45
46struct mptcp_rm_list {
47 u8 ids[MPTCP_RM_IDS_MAX];
48 u8 nr;
49};
50
51struct mptcp_addr_info {
52 u8 id;
53 sa_family_t family;
54 __be16 port;
55 union {
56 struct in_addr addr;
57#if IS_ENABLED(CONFIG_MPTCP_IPV6)
58 struct in6_addr addr6;
59#endif
60 };
61};
62
63struct mptcp_out_options {
64#if IS_ENABLED(CONFIG_MPTCP)
65 u16 suboptions;
66 struct mptcp_rm_list rm_list;
67 u8 join_id;
68 u8 backup;
69 u8 reset_reason:4,
70 reset_transient:1,
71 csum_reqd:1,
72 allow_join_id0:1;
73 union {
74 struct {
75 u64 sndr_key;
76 u64 rcvr_key;
77 u64 data_seq;
78 u32 subflow_seq;
79 u16 data_len;
80 __sum16 csum;
81 };
82 struct {
83 struct mptcp_addr_info addr;
84 u64 ahmac;
85 };
86 struct {
87 struct mptcp_ext ext_copy;
88 u64 fail_seq;
89 };
90 struct {
91 u32 nonce;
92 u32 token;
93 u64 thmac;
94 u8 hmac[MPTCPOPT_HMAC_LEN];
95 };
96 };
97#endif
98};
99
100#define MPTCP_SCHED_NAME_MAX 16
101#define MPTCP_SCHED_MAX 128
102#define MPTCP_SCHED_BUF_MAX (MPTCP_SCHED_NAME_MAX * MPTCP_SCHED_MAX)
103
104struct mptcp_sched_ops {
105 int (*get_send)(struct mptcp_sock *msk);
106 int (*get_retrans)(struct mptcp_sock *msk);
107
108 char name[MPTCP_SCHED_NAME_MAX];
109 struct module *owner;
110 struct list_head list;
111
112 void (*init)(struct mptcp_sock *msk);
113 void (*release)(struct mptcp_sock *msk);
114} ____cacheline_aligned_in_smp;
115
116#define MPTCP_PM_NAME_MAX 16
117#define MPTCP_PM_MAX 128
118#define MPTCP_PM_BUF_MAX (MPTCP_PM_NAME_MAX * MPTCP_PM_MAX)
119
120struct mptcp_pm_ops {
121 char name[MPTCP_PM_NAME_MAX];
122 struct module *owner;
123 struct list_head list;
124
125 void (*init)(struct mptcp_sock *msk);
126 void (*release)(struct mptcp_sock *msk);
127} ____cacheline_aligned_in_smp;
128
129#ifdef CONFIG_MPTCP
130void mptcp_init(void);
131
132static inline bool sk_is_mptcp(const struct sock *sk)
133{
134 return tcp_sk(sk)->is_mptcp;
135}
136
137static inline bool rsk_is_mptcp(const struct request_sock *req)
138{
139 return tcp_rsk(req)->is_mptcp;
140}
141
142static inline bool rsk_drop_req(const struct request_sock *req)
143{
144 return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
145}
146
147void mptcp_space(const struct sock *ssk, int *space, int *full_space);
148bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
149 unsigned int *size, struct mptcp_out_options *opts);
150bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
151 struct mptcp_out_options *opts);
152bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
153 unsigned int *size, unsigned int remaining,
154 struct mptcp_out_options *opts);
155bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
156
157void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
158 struct mptcp_out_options *opts);
159
160void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
161
162/* move the skb extension owership, with the assumption that 'to' is
163 * newly allocated
164 */
165static inline void mptcp_skb_ext_move(struct sk_buff *to,
166 struct sk_buff *from)
167{
168 if (!skb_ext_exist(skb: from, id: SKB_EXT_MPTCP))
169 return;
170
171 if (WARN_ON_ONCE(to->active_extensions))
172 skb_ext_put(skb: to);
173
174 to->active_extensions = from->active_extensions;
175 to->extensions = from->extensions;
176 from->active_extensions = 0;
177}
178
179static inline void mptcp_skb_ext_copy(struct sk_buff *to,
180 struct sk_buff *from)
181{
182 struct mptcp_ext *from_ext;
183
184 from_ext = skb_ext_find(skb: from, id: SKB_EXT_MPTCP);
185 if (!from_ext)
186 return;
187
188 from_ext->frozen = 1;
189 skb_ext_copy(dst: to, src: from);
190}
191
192static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
193 const struct mptcp_ext *from_ext)
194{
195 /* MPTCP always clears the ext when adding it to the skb, so
196 * holes do not bother us here
197 */
198 return !from_ext ||
199 (to_ext && from_ext &&
200 !memcmp(p: from_ext, q: to_ext, size: sizeof(struct mptcp_ext)));
201}
202
203/* check if skbs can be collapsed.
204 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
205 * mapping, or if the extension of @to is the same as @from.
206 * Collapsing is not possible if @to lacks an extension, but @from carries one.
207 */
208static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
209 const struct sk_buff *from)
210{
211 return mptcp_ext_matches(to_ext: skb_ext_find(skb: to, id: SKB_EXT_MPTCP),
212 from_ext: skb_ext_find(skb: from, id: SKB_EXT_MPTCP));
213}
214
215void mptcp_seq_show(struct seq_file *seq);
216int mptcp_subflow_init_cookie_req(struct request_sock *req,
217 const struct sock *sk_listener,
218 struct sk_buff *skb);
219struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
220 struct sock *sk_listener,
221 bool attach_listener);
222
223__be32 mptcp_get_reset_option(const struct sk_buff *skb);
224
225static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
226{
227 if (skb_ext_exist(skb, id: SKB_EXT_MPTCP))
228 return mptcp_get_reset_option(skb);
229
230 return htonl(0u);
231}
232
233void mptcp_active_detect_blackhole(struct sock *sk, bool expired);
234#else
235
236static inline void mptcp_init(void)
237{
238}
239
240static inline bool sk_is_mptcp(const struct sock *sk)
241{
242 return false;
243}
244
245static inline bool rsk_is_mptcp(const struct request_sock *req)
246{
247 return false;
248}
249
250static inline bool rsk_drop_req(const struct request_sock *req)
251{
252 return false;
253}
254
255static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
256 unsigned int *size,
257 struct mptcp_out_options *opts)
258{
259 return false;
260}
261
262static inline bool mptcp_synack_options(const struct request_sock *req,
263 unsigned int *size,
264 struct mptcp_out_options *opts)
265{
266 return false;
267}
268
269static inline bool mptcp_established_options(struct sock *sk,
270 struct sk_buff *skb,
271 unsigned int *size,
272 unsigned int remaining,
273 struct mptcp_out_options *opts)
274{
275 return false;
276}
277
278static inline bool mptcp_incoming_options(struct sock *sk,
279 struct sk_buff *skb)
280{
281 return true;
282}
283
284static inline void mptcp_skb_ext_move(struct sk_buff *to,
285 const struct sk_buff *from)
286{
287}
288
289static inline void mptcp_skb_ext_copy(struct sk_buff *to,
290 struct sk_buff *from)
291{
292}
293
294static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
295 const struct sk_buff *from)
296{
297 return true;
298}
299
300static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
301static inline void mptcp_seq_show(struct seq_file *seq) { }
302
303static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
304 const struct sock *sk_listener,
305 struct sk_buff *skb)
306{
307 return 0; /* TCP fallback */
308}
309
310static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
311 struct sock *sk_listener,
312 bool attach_listener)
313{
314 return NULL;
315}
316
317static inline __be32 mptcp_reset_option(const struct sk_buff *skb) { return htonl(0u); }
318
319static inline void mptcp_active_detect_blackhole(struct sock *sk, bool expired) { }
320#endif /* CONFIG_MPTCP */
321
322#if IS_ENABLED(CONFIG_MPTCP_IPV6)
323int mptcpv6_init(void);
324void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
325#elif IS_ENABLED(CONFIG_IPV6)
326static inline int mptcpv6_init(void) { return 0; }
327static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
328#endif
329
330#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
331struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
332#else
333static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
334#endif
335
336#if !IS_ENABLED(CONFIG_MPTCP)
337struct mptcp_sock { };
338#endif
339
340#endif /* __NET_MPTCP_H */
341

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