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2874c5fd | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
2e6599cb ACM |
2 | /* |
3 | * NET Generic infrastructure for Network protocols. | |
4 | * | |
fee83d09 | 5 | * Definitions for request_sock |
2e6599cb ACM |
6 | * |
7 | * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
8 | * | |
9 | * From code originally in include/net/tcp.h | |
2e6599cb ACM |
10 | */ |
11 | #ifndef _REQUEST_SOCK_H | |
12 | #define _REQUEST_SOCK_H | |
13 | ||
14 | #include <linux/slab.h> | |
0e87506f | 15 | #include <linux/spinlock.h> |
2e6599cb | 16 | #include <linux/types.h> |
547b792c | 17 | #include <linux/bug.h> |
41c6d650 | 18 | #include <linux/refcount.h> |
0e87506f | 19 | |
2e6599cb ACM |
20 | #include <net/sock.h> |
21 | ||
60236fdd | 22 | struct request_sock; |
2e6599cb ACM |
23 | struct sk_buff; |
24 | struct dst_entry; | |
25 | struct proto; | |
26 | ||
60236fdd | 27 | struct request_sock_ops { |
2e6599cb | 28 | int family; |
417ccf6b | 29 | unsigned int obj_size; |
e18b890b | 30 | struct kmem_cache *slab; |
7e56b5d6 | 31 | char *slab_name; |
ea3bea3a | 32 | int (*rtx_syn_ack)(const struct sock *sk, |
1a2c6181 | 33 | struct request_sock *req); |
a00e7444 | 34 | void (*send_ack)(const struct sock *sk, struct sk_buff *skb, |
60236fdd | 35 | struct request_sock *req); |
a00e7444 | 36 | void (*send_reset)(const struct sock *sk, |
cfb6eeb4 | 37 | struct sk_buff *skb); |
60236fdd | 38 | void (*destructor)(struct request_sock *req); |
42cb80a2 | 39 | void (*syn_ack_timeout)(const struct request_sock *req); |
2e6599cb ACM |
40 | }; |
41 | ||
1b70e977 | 42 | int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req); |
e6c022a4 | 43 | |
70a217f1 | 44 | struct saved_syn { |
267cf9fa | 45 | u32 mac_hdrlen; |
70a217f1 MKL |
46 | u32 network_hdrlen; |
47 | u32 tcp_hdrlen; | |
48 | u8 data[]; | |
49 | }; | |
50 | ||
60236fdd | 51 | /* struct request_sock - mini sock to represent a connection request |
2e6599cb | 52 | */ |
60236fdd | 53 | struct request_sock { |
634fb979 | 54 | struct sock_common __req_common; |
1e2e0117 | 55 | #define rsk_refcnt __req_common.skc_refcnt |
52452c54 | 56 | #define rsk_hash __req_common.skc_hash |
8e5eb54d | 57 | #define rsk_listener __req_common.skc_listener |
ed53d0ab ED |
58 | #define rsk_window_clamp __req_common.skc_window_clamp |
59 | #define rsk_rcv_wnd __req_common.skc_rcv_wnd | |
1e2e0117 | 60 | |
3fb62c5d | 61 | struct request_sock *dl_next; |
2e6599cb | 62 | u16 mss; |
e6c022a4 | 63 | u8 num_retrans; /* number of retransmits */ |
956c0d61 KI |
64 | u8 syncookie:1; /* True if |
65 | * 1) tcpopts needs to be encoded in | |
66 | * TS of SYN+ACK | |
67 | * 2) ACK is validated by BPF kfunc. | |
68 | */ | |
e6c022a4 | 69 | u8 num_timeout:7; /* number of timeouts */ |
2e6599cb | 70 | u32 ts_recent; |
fa76ce73 | 71 | struct timer_list rsk_timer; |
72a3effa | 72 | const struct request_sock_ops *rsk_ops; |
2e6599cb | 73 | struct sock *sk; |
70a217f1 | 74 | struct saved_syn *saved_syn; |
4237c75c | 75 | u32 secid; |
6b877699 | 76 | u32 peer_secid; |
5903123f | 77 | u32 timeout; |
2e6599cb ACM |
78 | }; |
79 | ||
b1f0a0e9 | 80 | static inline struct request_sock *inet_reqsk(const struct sock *sk) |
b267cdd1 ED |
81 | { |
82 | return (struct request_sock *)sk; | |
83 | } | |
84 | ||
85 | static inline struct sock *req_to_sk(struct request_sock *req) | |
86 | { | |
87 | return (struct sock *)req; | |
88 | } | |
89 | ||
95e752b5 KI |
90 | /** |
91 | * skb_steal_sock - steal a socket from an sk_buff | |
92 | * @skb: sk_buff to steal the socket from | |
93 | * @refcounted: is set to true if the socket is reference-counted | |
94 | * @prefetched: is set to true if the socket was assigned from bpf | |
95 | */ | |
96 | static inline struct sock *skb_steal_sock(struct sk_buff *skb, | |
97 | bool *refcounted, bool *prefetched) | |
98 | { | |
99 | struct sock *sk = skb->sk; | |
100 | ||
101 | if (!sk) { | |
102 | *prefetched = false; | |
103 | *refcounted = false; | |
104 | return NULL; | |
105 | } | |
106 | ||
107 | *prefetched = skb_sk_is_prefetched(skb); | |
8b5ac68f KI |
108 | if (*prefetched) { |
109 | #if IS_ENABLED(CONFIG_SYN_COOKIES) | |
110 | if (sk->sk_state == TCP_NEW_SYN_RECV && inet_reqsk(sk)->syncookie) { | |
111 | struct request_sock *req = inet_reqsk(sk); | |
112 | ||
113 | *refcounted = false; | |
114 | sk = req->rsk_listener; | |
115 | req->rsk_listener = NULL; | |
116 | return sk; | |
117 | } | |
118 | #endif | |
95e752b5 | 119 | *refcounted = sk_is_refcounted(sk); |
8b5ac68f | 120 | } else { |
95e752b5 | 121 | *refcounted = true; |
8b5ac68f | 122 | } |
95e752b5 KI |
123 | |
124 | skb->destructor = NULL; | |
125 | skb->sk = NULL; | |
126 | return sk; | |
127 | } | |
128 | ||
4e9a578e | 129 | static inline struct request_sock * |
a1a5344d ED |
130 | reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener, |
131 | bool attach_listener) | |
2e6599cb | 132 | { |
e96f78ab ED |
133 | struct request_sock *req; |
134 | ||
135 | req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN); | |
3a5d1c0e ED |
136 | if (!req) |
137 | return NULL; | |
138 | req->rsk_listener = NULL; | |
139 | if (attach_listener) { | |
41c6d650 | 140 | if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) { |
3a5d1c0e ED |
141 | kmem_cache_free(ops->slab, req); |
142 | return NULL; | |
a1a5344d | 143 | } |
3a5d1c0e | 144 | req->rsk_listener = sk_listener; |
4e9a578e | 145 | } |
3a5d1c0e ED |
146 | req->rsk_ops = ops; |
147 | req_to_sk(req)->sk_prot = sk_listener->sk_prot; | |
148 | sk_node_init(&req_to_sk(req)->sk_node); | |
149 | sk_tx_queue_clear(req_to_sk(req)); | |
150 | req->saved_syn = NULL; | |
956c0d61 | 151 | req->syncookie = 0; |
5903123f | 152 | req->timeout = 0; |
85f9aa75 ED |
153 | req->num_timeout = 0; |
154 | req->num_retrans = 0; | |
155 | req->sk = NULL; | |
41c6d650 | 156 | refcount_set(&req->rsk_refcnt, 0); |
3a5d1c0e | 157 | |
2e6599cb ACM |
158 | return req; |
159 | } | |
160 | ||
9403cf23 | 161 | static inline void __reqsk_free(struct request_sock *req) |
2e6599cb | 162 | { |
60236fdd | 163 | req->rsk_ops->destructor(req); |
4e9a578e ED |
164 | if (req->rsk_listener) |
165 | sock_put(req->rsk_listener); | |
cd8ae852 | 166 | kfree(req->saved_syn); |
13854e5a | 167 | kmem_cache_free(req->rsk_ops->slab, req); |
2e6599cb ACM |
168 | } |
169 | ||
9403cf23 GN |
170 | static inline void reqsk_free(struct request_sock *req) |
171 | { | |
172 | WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0); | |
173 | __reqsk_free(req); | |
174 | } | |
175 | ||
1e2e0117 ED |
176 | static inline void reqsk_put(struct request_sock *req) |
177 | { | |
41c6d650 | 178 | if (refcount_dec_and_test(&req->rsk_refcnt)) |
1e2e0117 ED |
179 | reqsk_free(req); |
180 | } | |
181 | ||
10467163 JC |
182 | /* |
183 | * For a TCP Fast Open listener - | |
184 | * lock - protects the access to all the reqsk, which is co-owned by | |
185 | * the listener and the child socket. | |
186 | * qlen - pending TFO requests (still in TCP_SYN_RECV). | |
187 | * max_qlen - max TFO reqs allowed before TFO is disabled. | |
188 | * | |
189 | * XXX (TFO) - ideally these fields can be made as part of "listen_sock" | |
190 | * structure above. But there is some implementation difficulty due to | |
191 | * listen_sock being part of request_sock_queue hence will be freed when | |
192 | * a listener is stopped. But TFO related fields may continue to be | |
193 | * accessed even after a listener is closed, until its sk_refcnt drops | |
194 | * to 0 implying no more outstanding TFO reqs. One solution is to keep | |
195 | * listen_opt around until sk_refcnt drops to 0. But there is some other | |
196 | * complexity that needs to be resolved. E.g., a listener can be disabled | |
197 | * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. | |
198 | */ | |
199 | struct fastopen_queue { | |
200 | struct request_sock *rskq_rst_head; /* Keep track of past TFO */ | |
201 | struct request_sock *rskq_rst_tail; /* requests that caused RST. | |
202 | * This is part of the defense | |
203 | * against spoofing attack. | |
204 | */ | |
205 | spinlock_t lock; | |
206 | int qlen; /* # of pending (TCP_SYN_RECV) reqs */ | |
207 | int max_qlen; /* != 0 iff TFO is currently enabled */ | |
1fba70e5 YC |
208 | |
209 | struct tcp_fastopen_context __rcu *ctx; /* cipher context for cookie */ | |
10467163 JC |
210 | }; |
211 | ||
0e87506f ACM |
212 | /** struct request_sock_queue - queue of request_socks |
213 | * | |
214 | * @rskq_accept_head - FIFO head of established children | |
215 | * @rskq_accept_tail - FIFO tail of established children | |
295f7324 | 216 | * @rskq_defer_accept - User waits for some data after accept() |
0e87506f | 217 | * |
0e87506f ACM |
218 | */ |
219 | struct request_sock_queue { | |
fff1f300 ED |
220 | spinlock_t rskq_lock; |
221 | u8 rskq_defer_accept; | |
ef547f2a | 222 | |
8d2675f1 | 223 | u32 synflood_warned; |
aac065c5 ED |
224 | atomic_t qlen; |
225 | atomic_t young; | |
226 | ||
0e87506f ACM |
227 | struct request_sock *rskq_accept_head; |
228 | struct request_sock *rskq_accept_tail; | |
0536fcc0 ED |
229 | struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine |
230 | * if TFO is enabled. | |
10467163 | 231 | */ |
0e87506f ACM |
232 | }; |
233 | ||
ef547f2a | 234 | void reqsk_queue_alloc(struct request_sock_queue *queue); |
0e87506f | 235 | |
c0f4502a JP |
236 | void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, |
237 | bool reset); | |
83e3609e | 238 | |
fff1f300 | 239 | static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) |
0e87506f | 240 | { |
60b173ca | 241 | return READ_ONCE(queue->rskq_accept_head) == NULL; |
0e87506f ACM |
242 | } |
243 | ||
fff1f300 ED |
244 | static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, |
245 | struct sock *parent) | |
0e87506f | 246 | { |
fff1f300 | 247 | struct request_sock *req; |
0e87506f | 248 | |
fff1f300 ED |
249 | spin_lock_bh(&queue->rskq_lock); |
250 | req = queue->rskq_accept_head; | |
251 | if (req) { | |
252 | sk_acceptq_removed(parent); | |
60b173ca | 253 | WRITE_ONCE(queue->rskq_accept_head, req->dl_next); |
fff1f300 ED |
254 | if (queue->rskq_accept_head == NULL) |
255 | queue->rskq_accept_tail = NULL; | |
256 | } | |
257 | spin_unlock_bh(&queue->rskq_lock); | |
0e87506f ACM |
258 | return req; |
259 | } | |
260 | ||
fa76ce73 ED |
261 | static inline void reqsk_queue_removed(struct request_sock_queue *queue, |
262 | const struct request_sock *req) | |
0e87506f | 263 | { |
e6c022a4 | 264 | if (req->num_timeout == 0) |
aac065c5 ED |
265 | atomic_dec(&queue->young); |
266 | atomic_dec(&queue->qlen); | |
0e87506f ACM |
267 | } |
268 | ||
fa76ce73 | 269 | static inline void reqsk_queue_added(struct request_sock_queue *queue) |
0e87506f | 270 | { |
aac065c5 ED |
271 | atomic_inc(&queue->young); |
272 | atomic_inc(&queue->qlen); | |
0e87506f ACM |
273 | } |
274 | ||
fa76ce73 | 275 | static inline int reqsk_queue_len(const struct request_sock_queue *queue) |
0e87506f | 276 | { |
aac065c5 | 277 | return atomic_read(&queue->qlen); |
0e87506f ACM |
278 | } |
279 | ||
fa76ce73 | 280 | static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) |
0e87506f | 281 | { |
aac065c5 | 282 | return atomic_read(&queue->young); |
fa76ce73 | 283 | } |
0470c8ca | 284 | |
2e6599cb | 285 | #endif /* _REQUEST_SOCK_H */ |