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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#define MPTCP_SCHED_NAME_MAX 16
100#define MPTCP_SUBFLOWS_MAX 8
101
102struct mptcp_sched_data {
103 bool reinject;
104 u8 subflows;
105 struct mptcp_subflow_context *contexts[MPTCP_SUBFLOWS_MAX];
106};
107
108struct mptcp_sched_ops {
109 int (*get_subflow)(struct mptcp_sock *msk,
110 struct mptcp_sched_data *data);
111
112 char name[MPTCP_SCHED_NAME_MAX];
113 struct module *owner;
114 struct list_head list;
115
116 void (*init)(struct mptcp_sock *msk);
117 void (*release)(struct mptcp_sock *msk);
118} ____cacheline_aligned_in_smp;
119
120#ifdef CONFIG_MPTCP
121void mptcp_init(void);
122
123static inline bool sk_is_mptcp(const struct sock *sk)
124{
125 return tcp_sk(sk)->is_mptcp;
126}
127
128static inline bool rsk_is_mptcp(const struct request_sock *req)
129{
130 return tcp_rsk(req)->is_mptcp;
131}
132
133static inline bool rsk_drop_req(const struct request_sock *req)
134{
135 return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
136}
137
138void mptcp_space(const struct sock *ssk, int *space, int *full_space);
139bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
140 unsigned int *size, struct mptcp_out_options *opts);
141bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
142 struct mptcp_out_options *opts);
143bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
144 unsigned int *size, unsigned int remaining,
145 struct mptcp_out_options *opts);
146bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb);
147
148void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp,
149 struct mptcp_out_options *opts);
150
151void mptcp_diag_fill_info(struct mptcp_sock *msk, struct mptcp_info *info);
152
153/* move the skb extension owership, with the assumption that 'to' is
154 * newly allocated
155 */
156static inline void mptcp_skb_ext_move(struct sk_buff *to,
157 struct sk_buff *from)
158{
159 if (!skb_ext_exist(from, SKB_EXT_MPTCP))
160 return;
161
162 if (WARN_ON_ONCE(to->active_extensions))
163 skb_ext_put(to);
164
165 to->active_extensions = from->active_extensions;
166 to->extensions = from->extensions;
167 from->active_extensions = 0;
168}
169
170static inline void mptcp_skb_ext_copy(struct sk_buff *to,
171 struct sk_buff *from)
172{
173 struct mptcp_ext *from_ext;
174
175 from_ext = skb_ext_find(from, SKB_EXT_MPTCP);
176 if (!from_ext)
177 return;
178
179 from_ext->frozen = 1;
180 skb_ext_copy(to, from);
181}
182
183static inline bool mptcp_ext_matches(const struct mptcp_ext *to_ext,
184 const struct mptcp_ext *from_ext)
185{
186 /* MPTCP always clears the ext when adding it to the skb, so
187 * holes do not bother us here
188 */
189 return !from_ext ||
190 (to_ext && from_ext &&
191 !memcmp(from_ext, to_ext, sizeof(struct mptcp_ext)));
192}
193
194/* check if skbs can be collapsed.
195 * MPTCP collapse is allowed if neither @to or @from carry an mptcp data
196 * mapping, or if the extension of @to is the same as @from.
197 * Collapsing is not possible if @to lacks an extension, but @from carries one.
198 */
199static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
200 const struct sk_buff *from)
201{
202 return mptcp_ext_matches(skb_ext_find(to, SKB_EXT_MPTCP),
203 skb_ext_find(from, SKB_EXT_MPTCP));
204}
205
206void mptcp_seq_show(struct seq_file *seq);
207int mptcp_subflow_init_cookie_req(struct request_sock *req,
208 const struct sock *sk_listener,
209 struct sk_buff *skb);
210struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
211 struct sock *sk_listener,
212 bool attach_listener);
213
214__be32 mptcp_get_reset_option(const struct sk_buff *skb);
215
216static inline __be32 mptcp_reset_option(const struct sk_buff *skb)
217{
218 if (skb_ext_exist(skb, SKB_EXT_MPTCP))
219 return mptcp_get_reset_option(skb);
220
221 return htonl(0u);
222}
223#else
224
225static inline void mptcp_init(void)
226{
227}
228
229static inline bool sk_is_mptcp(const struct sock *sk)
230{
231 return false;
232}
233
234static inline bool rsk_is_mptcp(const struct request_sock *req)
235{
236 return false;
237}
238
239static inline bool rsk_drop_req(const struct request_sock *req)
240{
241 return false;
242}
243
244static inline bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
245 unsigned int *size,
246 struct mptcp_out_options *opts)
247{
248 return false;
249}
250
251static inline bool mptcp_synack_options(const struct request_sock *req,
252 unsigned int *size,
253 struct mptcp_out_options *opts)
254{
255 return false;
256}
257
258static inline bool mptcp_established_options(struct sock *sk,
259 struct sk_buff *skb,
260 unsigned int *size,
261 unsigned int remaining,
262 struct mptcp_out_options *opts)
263{
264 return false;
265}
266
267static inline bool mptcp_incoming_options(struct sock *sk,
268 struct sk_buff *skb)
269{
270 return true;
271}
272
273static inline void mptcp_skb_ext_move(struct sk_buff *to,
274 const struct sk_buff *from)
275{
276}
277
278static inline void mptcp_skb_ext_copy(struct sk_buff *to,
279 struct sk_buff *from)
280{
281}
282
283static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
284 const struct sk_buff *from)
285{
286 return true;
287}
288
289static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
290static inline void mptcp_seq_show(struct seq_file *seq) { }
291
292static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
293 const struct sock *sk_listener,
294 struct sk_buff *skb)
295{
296 return 0; /* TCP fallback */
297}
298
299static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
300 struct sock *sk_listener,
301 bool attach_listener)
302{
303 return NULL;
304}
305
306static inline __be32 mptcp_reset_option(const struct sk_buff *skb) { return htonl(0u); }
307#endif /* CONFIG_MPTCP */
308
309#if IS_ENABLED(CONFIG_MPTCP_IPV6)
310int mptcpv6_init(void);
311void mptcpv6_handle_mapped(struct sock *sk, bool mapped);
312#elif IS_ENABLED(CONFIG_IPV6)
313static inline int mptcpv6_init(void) { return 0; }
314static inline void mptcpv6_handle_mapped(struct sock *sk, bool mapped) { }
315#endif
316
317#if defined(CONFIG_MPTCP) && defined(CONFIG_BPF_SYSCALL)
318struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk);
319#else
320static inline struct mptcp_sock *bpf_mptcp_sock_from_subflow(struct sock *sk) { return NULL; }
321#endif
322
323#if !IS_ENABLED(CONFIG_MPTCP)
324struct mptcp_sock { };
325#endif
326
327#endif /* __NET_MPTCP_H */