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Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -07001/*
2 * NET Generic infrastructure for Network protocols.
3 *
4 * Definitions for request_sock
5 *
6 * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
7 *
8 * From code originally in include/net/tcp.h
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15#ifndef _REQUEST_SOCK_H
16#define _REQUEST_SOCK_H
17
18#include <linux/slab.h>
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070019#include <linux/spinlock.h>
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070020#include <linux/types.h>
Ilpo Järvinen547b7922008-07-25 21:43:18 -070021#include <linux/bug.h>
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070022
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070023#include <net/sock.h>
24
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070025struct request_sock;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070026struct sk_buff;
27struct dst_entry;
28struct proto;
29
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070030struct request_sock_ops {
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070031 int family;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070032 int obj_size;
Christoph Lametere18b8902006-12-06 20:33:20 -080033 struct kmem_cache *slab;
Catalin Marinas7e56b5d2008-11-21 16:45:22 -080034 char *slab_name;
Eric Dumazetea3bea32015-09-25 07:39:23 -070035 int (*rtx_syn_ack)(const struct sock *sk,
Christoph Paasch1a2c6182013-03-17 08:23:34 +000036 struct request_sock *req);
Eric Dumazeta00e7442015-09-29 07:42:39 -070037 void (*send_ack)(const struct sock *sk, struct sk_buff *skb,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070038 struct request_sock *req);
Eric Dumazeta00e7442015-09-29 07:42:39 -070039 void (*send_reset)(const struct sock *sk,
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -080040 struct sk_buff *skb);
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070041 void (*destructor)(struct request_sock *req);
Eric Dumazet42cb80a2015-03-22 10:22:19 -070042 void (*syn_ack_timeout)(const struct request_sock *req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070043};
44
Eric Dumazet1b70e972015-09-25 07:39:24 -070045int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req);
Eric Dumazete6c022a2012-10-27 23:16:46 +000046
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070047/* struct request_sock - mini sock to represent a connection request
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070048 */
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070049struct request_sock {
Eric Dumazet634fb9792013-10-09 15:21:29 -070050 struct sock_common __req_common;
Eric Dumazet1e2e0112015-03-12 16:44:06 -070051#define rsk_refcnt __req_common.skc_refcnt
Eric Dumazet52452c52015-03-19 19:04:19 -070052#define rsk_hash __req_common.skc_hash
Eric Dumazet8e5eb542015-10-08 19:33:22 -070053#define rsk_listener __req_common.skc_listener
Eric Dumazet1e2e0112015-03-12 16:44:06 -070054
Eric Dumazet3fb62c52013-04-19 14:29:25 -070055 struct request_sock *dl_next;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070056 u16 mss;
Eric Dumazete6c022a2012-10-27 23:16:46 +000057 u8 num_retrans; /* number of retransmits */
58 u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */
59 u8 num_timeout:7; /* number of timeouts */
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070060 /* The following two fields can be easily recomputed I think -AK */
61 u32 window_clamp; /* window clamp at creation time */
62 u32 rcv_wnd; /* rcv_wnd offered first time */
63 u32 ts_recent;
Eric Dumazetfa76ce732015-03-19 19:04:20 -070064 struct timer_list rsk_timer;
Eric Dumazet72a3eff2006-11-16 02:30:37 -080065 const struct request_sock_ops *rsk_ops;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070066 struct sock *sk;
Eric Dumazetcd8ae852015-05-03 21:34:46 -070067 u32 *saved_syn;
Venkat Yekkirala4237c752006-07-24 23:32:50 -070068 u32 secid;
Venkat Yekkirala6b877692006-11-08 17:04:09 -060069 u32 peer_secid;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070070};
71
Eric Dumazetb267cdd2015-10-02 11:43:27 -070072static inline struct request_sock *inet_reqsk(struct sock *sk)
73{
74 return (struct request_sock *)sk;
75}
76
77static inline struct sock *req_to_sk(struct request_sock *req)
78{
79 return (struct sock *)req;
80}
81
Eric Dumazet4e9a5782015-03-17 18:32:28 -070082static inline struct request_sock *
Eric Dumazeta1a53442015-10-04 21:08:11 -070083reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
84 bool attach_listener)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070085{
Eric Dumazete96f78a2015-10-03 06:27:28 -070086 struct request_sock *req;
87
88 req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070089
Eric Dumazet4e9a5782015-03-17 18:32:28 -070090 if (req) {
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070091 req->rsk_ops = ops;
Eric Dumazeta1a53442015-10-04 21:08:11 -070092 if (attach_listener) {
93 sock_hold(sk_listener);
94 req->rsk_listener = sk_listener;
95 } else {
96 req->rsk_listener = NULL;
97 }
Eric Dumazetb267cdd2015-10-02 11:43:27 -070098 req_to_sk(req)->sk_prot = sk_listener->sk_prot;
99 sk_node_init(&req_to_sk(req)->sk_node);
Eric Dumazet004a5d02015-10-04 21:08:10 -0700100 sk_tx_queue_clear(req_to_sk(req));
Eric Dumazetcd8ae852015-05-03 21:34:46 -0700101 req->saved_syn = NULL;
Eric Dumazet0470c8c2015-03-17 18:32:31 -0700102 /* Following is temporary. It is coupled with debugging
103 * helpers in reqsk_put() & reqsk_free()
104 */
105 atomic_set(&req->rsk_refcnt, 0);
Eric Dumazet4e9a5782015-03-17 18:32:28 -0700106 }
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -0700107 return req;
108}
109
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -0700110static inline void reqsk_free(struct request_sock *req)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -0700111{
Eric Dumazet13854e52015-03-15 21:12:16 -0700112 /* temporary debugging */
113 WARN_ON_ONCE(atomic_read(&req->rsk_refcnt) != 0);
114
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -0700115 req->rsk_ops->destructor(req);
Eric Dumazet4e9a5782015-03-17 18:32:28 -0700116 if (req->rsk_listener)
117 sock_put(req->rsk_listener);
Eric Dumazetcd8ae852015-05-03 21:34:46 -0700118 kfree(req->saved_syn);
Eric Dumazet13854e52015-03-15 21:12:16 -0700119 kmem_cache_free(req->rsk_ops->slab, req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -0700120}
121
Eric Dumazet1e2e0112015-03-12 16:44:06 -0700122static inline void reqsk_put(struct request_sock *req)
123{
124 if (atomic_dec_and_test(&req->rsk_refcnt))
125 reqsk_free(req);
126}
127
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700128extern int sysctl_max_syn_backlog;
129
Jerry Chu10467162012-08-31 12:29:11 +0000130/*
131 * For a TCP Fast Open listener -
132 * lock - protects the access to all the reqsk, which is co-owned by
133 * the listener and the child socket.
134 * qlen - pending TFO requests (still in TCP_SYN_RECV).
135 * max_qlen - max TFO reqs allowed before TFO is disabled.
136 *
137 * XXX (TFO) - ideally these fields can be made as part of "listen_sock"
138 * structure above. But there is some implementation difficulty due to
139 * listen_sock being part of request_sock_queue hence will be freed when
140 * a listener is stopped. But TFO related fields may continue to be
141 * accessed even after a listener is closed, until its sk_refcnt drops
142 * to 0 implying no more outstanding TFO reqs. One solution is to keep
143 * listen_opt around until sk_refcnt drops to 0. But there is some other
144 * complexity that needs to be resolved. E.g., a listener can be disabled
145 * temporarily through shutdown()->tcp_disconnect(), and re-enabled later.
146 */
147struct fastopen_queue {
148 struct request_sock *rskq_rst_head; /* Keep track of past TFO */
149 struct request_sock *rskq_rst_tail; /* requests that caused RST.
150 * This is part of the defense
151 * against spoofing attack.
152 */
153 spinlock_t lock;
154 int qlen; /* # of pending (TCP_SYN_RECV) reqs */
155 int max_qlen; /* != 0 iff TFO is currently enabled */
156};
157
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700158/** struct request_sock_queue - queue of request_socks
159 *
160 * @rskq_accept_head - FIFO head of established children
161 * @rskq_accept_tail - FIFO tail of established children
Arnaldo Carvalho de Melo295f7322005-08-09 20:11:56 -0700162 * @rskq_defer_accept - User waits for some data after accept()
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700163 *
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700164 */
165struct request_sock_queue {
Eric Dumazetfff1f302015-10-02 11:43:23 -0700166 spinlock_t rskq_lock;
167 u8 rskq_defer_accept;
Eric Dumazetef547f22015-10-02 11:43:37 -0700168
Eric Dumazet8d2675f2015-10-02 11:43:25 -0700169 u32 synflood_warned;
Eric Dumazetaac065c2015-10-02 11:43:24 -0700170 atomic_t qlen;
171 atomic_t young;
172
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700173 struct request_sock *rskq_accept_head;
174 struct request_sock *rskq_accept_tail;
Eric Dumazet0536fcc2015-09-29 07:42:52 -0700175 struct fastopen_queue fastopenq; /* Check max_qlen != 0 to determine
176 * if TFO is enabled.
Jerry Chu10467162012-08-31 12:29:11 +0000177 */
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700178};
179
Eric Dumazetef547f22015-10-02 11:43:37 -0700180void reqsk_queue_alloc(struct request_sock_queue *queue);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700181
Joe Perchesc0f45022013-09-22 10:32:20 -0700182void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
183 bool reset);
Arnaldo Carvalho de Melo83e36092005-08-09 19:33:31 -0700184
Eric Dumazetfff1f302015-10-02 11:43:23 -0700185static inline bool reqsk_queue_empty(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700186{
187 return queue->rskq_accept_head == NULL;
188}
189
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700190static inline void reqsk_queue_add(struct request_sock_queue *queue,
191 struct request_sock *req,
192 struct sock *parent,
193 struct sock *child)
194{
Eric Dumazetfff1f302015-10-02 11:43:23 -0700195 spin_lock(&queue->rskq_lock);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700196 req->sk = child;
197 sk_acceptq_added(parent);
198
199 if (queue->rskq_accept_head == NULL)
200 queue->rskq_accept_head = req;
201 else
202 queue->rskq_accept_tail->dl_next = req;
203
204 queue->rskq_accept_tail = req;
205 req->dl_next = NULL;
Eric Dumazetfff1f302015-10-02 11:43:23 -0700206 spin_unlock(&queue->rskq_lock);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700207}
208
Eric Dumazetfff1f302015-10-02 11:43:23 -0700209static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue,
210 struct sock *parent)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700211{
Eric Dumazetfff1f302015-10-02 11:43:23 -0700212 struct request_sock *req;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700213
Eric Dumazetfff1f302015-10-02 11:43:23 -0700214 spin_lock_bh(&queue->rskq_lock);
215 req = queue->rskq_accept_head;
216 if (req) {
217 sk_acceptq_removed(parent);
218 queue->rskq_accept_head = req->dl_next;
219 if (queue->rskq_accept_head == NULL)
220 queue->rskq_accept_tail = NULL;
221 }
222 spin_unlock_bh(&queue->rskq_lock);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700223 return req;
224}
225
Eric Dumazetfa76ce732015-03-19 19:04:20 -0700226static inline void reqsk_queue_removed(struct request_sock_queue *queue,
227 const struct request_sock *req)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700228{
Eric Dumazete6c022a2012-10-27 23:16:46 +0000229 if (req->num_timeout == 0)
Eric Dumazetaac065c2015-10-02 11:43:24 -0700230 atomic_dec(&queue->young);
231 atomic_dec(&queue->qlen);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700232}
233
Eric Dumazetfa76ce732015-03-19 19:04:20 -0700234static inline void reqsk_queue_added(struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700235{
Eric Dumazetaac065c2015-10-02 11:43:24 -0700236 atomic_inc(&queue->young);
237 atomic_inc(&queue->qlen);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700238}
239
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700240static inline int reqsk_queue_len(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700241{
Eric Dumazetaac065c2015-10-02 11:43:24 -0700242 return atomic_read(&queue->qlen);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700243}
244
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700245static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700246{
Eric Dumazetaac065c2015-10-02 11:43:24 -0700247 return atomic_read(&queue->young);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700248}
249
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -0700250#endif /* _REQUEST_SOCK_H */