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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 | |
60236fdd | 44 | /* struct request_sock - mini sock to represent a connection request |
2e6599cb | 45 | */ |
60236fdd | 46 | struct request_sock { |
634fb979 | 47 | struct sock_common __req_common; |
1e2e0117 | 48 | #define rsk_refcnt __req_common.skc_refcnt |
52452c54 | 49 | #define rsk_hash __req_common.skc_hash |
8e5eb54d | 50 | #define rsk_listener __req_common.skc_listener |
ed53d0ab ED |
51 | #define rsk_window_clamp __req_common.skc_window_clamp |
52 | #define rsk_rcv_wnd __req_common.skc_rcv_wnd | |
1e2e0117 | 53 | |
3fb62c5d | 54 | struct request_sock *dl_next; |
2e6599cb | 55 | u16 mss; |
e6c022a4 ED |
56 | u8 num_retrans; /* number of retransmits */ |
57 | u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */ | |
58 | u8 num_timeout:7; /* number of timeouts */ | |
2e6599cb | 59 | u32 ts_recent; |
fa76ce73 | 60 | struct timer_list rsk_timer; |
72a3effa | 61 | const struct request_sock_ops *rsk_ops; |
2e6599cb | 62 | struct sock *sk; |
cd8ae852 | 63 | u32 *saved_syn; |
4237c75c | 64 | u32 secid; |
6b877699 | 65 | u32 peer_secid; |
2e6599cb ACM |
66 | }; |
67 | ||
b1f0a0e9 | 68 | static inline struct request_sock *inet_reqsk(const struct sock *sk) |
b267cdd1 ED |
69 | { |
70 | return (struct request_sock *)sk; | |
71 | } | |
72 | ||
73 | static inline struct sock *req_to_sk(struct request_sock *req) | |
74 | { | |
75 | return (struct sock *)req; | |
76 | } | |
77 | ||
4e9a578e | 78 | static inline struct request_sock * |
a1a5344d ED |
79 | reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener, |
80 | bool attach_listener) | |
2e6599cb | 81 | { |
e96f78ab ED |
82 | struct request_sock *req; |
83 | ||
84 | req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN); | |
3a5d1c0e ED |
85 | if (!req) |
86 | return NULL; | |
87 | req->rsk_listener = NULL; | |
88 | if (attach_listener) { | |
41c6d650 | 89 | if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) { |
3a5d1c0e ED |
90 | kmem_cache_free(ops->slab, req); |
91 | return NULL; | |
a1a5344d | 92 | } |
3a5d1c0e | 93 | req->rsk_listener = sk_listener; |
4e9a578e | 94 | } |
3a5d1c0e ED |
95 | req->rsk_ops = ops; |
96 | req_to_sk(req)->sk_prot = sk_listener->sk_prot; | |
97 | sk_node_init(&req_to_sk(req)->sk_node); | |
98 | sk_tx_queue_clear(req_to_sk(req)); | |
99 | req->saved_syn = NULL; | |
85f9aa75 ED |
100 | req->num_timeout = 0; |
101 | req->num_retrans = 0; | |
102 | req->sk = NULL; | |
41c6d650 | 103 | refcount_set(&req->rsk_refcnt, 0); |
3a5d1c0e | 104 | |
2e6599cb ACM |
105 | return req; |
106 | } | |
107 | ||
9403cf23 | 108 | static inline void __reqsk_free(struct request_sock *req) |
2e6599cb | 109 | { |
60236fdd | 110 | req->rsk_ops->destructor(req); |
4e9a578e ED |
111 | if (req->rsk_listener) |
112 | sock_put(req->rsk_listener); | |
cd8ae852 | 113 | kfree(req->saved_syn); |
13854e5a | 114 | kmem_cache_free(req->rsk_ops->slab, req); |
2e6599cb ACM |
115 | } |
116 | ||
9403cf23 GN |
117 | static inline void reqsk_free(struct request_sock *req) |
118 | { | |
119 | WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0); | |
120 | __reqsk_free(req); | |
121 | } | |
122 | ||
1e2e0117 ED |
123 | static inline void reqsk_put(struct request_sock *req) |
124 | { | |
41c6d650 | 125 | if (refcount_dec_and_test(&req->rsk_refcnt)) |
1e2e0117 ED |
126 | reqsk_free(req); |
127 | } | |
128 | ||
10467163 JC |
129 | /* |
130 | * For a TCP Fast Open listener - | |
131 | * lock - protects the access to all the reqsk, which is co-owned by | |
132 | * the listener and the child socket. | |
133 | * qlen - pending TFO requests (still in TCP_SYN_RECV). | |
134 | * max_qlen - max TFO reqs allowed before TFO is disabled. | |
135 | * | |
136 | * XXX (TFO) - ideally these fields can be made as part of "listen_sock" | |
137 | * structure above. But there is some implementation difficulty due to | |
138 | * listen_sock being part of request_sock_queue hence will be freed when | |
139 | * a listener is stopped. But TFO related fields may continue to be | |
140 | * accessed even after a listener is closed, until its sk_refcnt drops | |
141 | * to 0 implying no more outstanding TFO reqs. One solution is to keep | |
142 | * listen_opt around until sk_refcnt drops to 0. But there is some other | |
143 | * complexity that needs to be resolved. E.g., a listener can be disabled | |
144 | * temporarily through shutdown()->tcp_disconnect(), and re-enabled later. | |
145 | */ | |
146 | struct fastopen_queue { | |
147 | struct request_sock *rskq_rst_head; /* Keep track of past TFO */ | |
148 | struct request_sock *rskq_rst_tail; /* requests that caused RST. | |
149 | * This is part of the defense | |
150 | * against spoofing attack. | |
151 | */ | |
152 | spinlock_t lock; | |
153 | int qlen; /* # of pending (TCP_SYN_RECV) reqs */ | |
154 | int max_qlen; /* != 0 iff TFO is currently enabled */ | |
1fba70e5 YC |
155 | |
156 | struct tcp_fastopen_context __rcu *ctx; /* cipher context for cookie */ | |
10467163 JC |
157 | }; |
158 | ||
0e87506f ACM |
159 | /** struct request_sock_queue - queue of request_socks |
160 | * | |
161 | * @rskq_accept_head - FIFO head of established children | |
162 | * @rskq_accept_tail - FIFO tail of established children | |
295f7324 | 163 | * @rskq_defer_accept - User waits for some data after accept() |
0e87506f | 164 | * |
0e87506f ACM |
165 | */ |
166 | struct request_sock_queue { | |
fff1f300 ED |
167 | spinlock_t rskq_lock; |
168 | u8 rskq_defer_accept; | |
ef547f2a | 169 | |
8d2675f1 | 170 | u32 synflood_warned; |
aac065c5 ED |
171 | atomic_t qlen; |
172 | atomic_t young; | |
173 | ||
0e87506f ACM |
174 | struct request_sock *rskq_accept_head; |
175 | struct request_sock *rskq_accept_tail; | |
0536fcc0 ED |
176 | struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine |
177 | * if TFO is enabled. | |
10467163 | 178 | */ |
0e87506f ACM |
179 | }; |
180 | ||
ef547f2a | 181 | void reqsk_queue_alloc(struct request_sock_queue *queue); |
0e87506f | 182 | |
c0f4502a JP |
183 | void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req, |
184 | bool reset); | |
83e3609e | 185 | |
fff1f300 | 186 | static inline bool reqsk_queue_empty(const struct request_sock_queue *queue) |
0e87506f | 187 | { |
60b173ca | 188 | return READ_ONCE(queue->rskq_accept_head) == NULL; |
0e87506f ACM |
189 | } |
190 | ||
fff1f300 ED |
191 | static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue, |
192 | struct sock *parent) | |
0e87506f | 193 | { |
fff1f300 | 194 | struct request_sock *req; |
0e87506f | 195 | |
fff1f300 ED |
196 | spin_lock_bh(&queue->rskq_lock); |
197 | req = queue->rskq_accept_head; | |
198 | if (req) { | |
199 | sk_acceptq_removed(parent); | |
60b173ca | 200 | WRITE_ONCE(queue->rskq_accept_head, req->dl_next); |
fff1f300 ED |
201 | if (queue->rskq_accept_head == NULL) |
202 | queue->rskq_accept_tail = NULL; | |
203 | } | |
204 | spin_unlock_bh(&queue->rskq_lock); | |
0e87506f ACM |
205 | return req; |
206 | } | |
207 | ||
fa76ce73 ED |
208 | static inline void reqsk_queue_removed(struct request_sock_queue *queue, |
209 | const struct request_sock *req) | |
0e87506f | 210 | { |
e6c022a4 | 211 | if (req->num_timeout == 0) |
aac065c5 ED |
212 | atomic_dec(&queue->young); |
213 | atomic_dec(&queue->qlen); | |
0e87506f ACM |
214 | } |
215 | ||
fa76ce73 | 216 | static inline void reqsk_queue_added(struct request_sock_queue *queue) |
0e87506f | 217 | { |
aac065c5 ED |
218 | atomic_inc(&queue->young); |
219 | atomic_inc(&queue->qlen); | |
0e87506f ACM |
220 | } |
221 | ||
fa76ce73 | 222 | static inline int reqsk_queue_len(const struct request_sock_queue *queue) |
0e87506f | 223 | { |
aac065c5 | 224 | return atomic_read(&queue->qlen); |
0e87506f ACM |
225 | } |
226 | ||
fa76ce73 | 227 | static inline int reqsk_queue_len_young(const struct request_sock_queue *queue) |
0e87506f | 228 | { |
aac065c5 | 229 | return atomic_read(&queue->young); |
fa76ce73 | 230 | } |
0470c8ca | 231 | |
2e6599cb | 232 | #endif /* _REQUEST_SOCK_H */ |