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1/*
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>
19#include <linux/spinlock.h>
20#include <linux/types.h>
21#include <linux/bug.h>
22
23#include <net/sock.h>
24
25struct request_sock;
26struct sk_buff;
27struct dst_entry;
28struct proto;
29
30/* empty to "strongly type" an otherwise void parameter.
31 */
32struct request_values {
33};
34
35struct request_sock_ops {
36 int family;
37 int obj_size;
38 struct kmem_cache *slab;
39 char *slab_name;
40 int (*rtx_syn_ack)(struct sock *sk,
41 struct request_sock *req,
42 struct request_values *rvp);
43 void (*send_ack)(struct sock *sk, struct sk_buff *skb,
44 struct request_sock *req);
45 void (*send_reset)(struct sock *sk,
46 struct sk_buff *skb);
47 void (*destructor)(struct request_sock *req);
48 void (*syn_ack_timeout)(struct sock *sk,
49 struct request_sock *req);
50};
51
52/* struct request_sock - mini sock to represent a connection request
53 */
54struct request_sock {
55 struct request_sock *dl_next; /* Must be first member! */
56 u16 mss;
57 u8 retrans;
58 u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
59 /* The following two fields can be easily recomputed I think -AK */
60 u32 window_clamp; /* window clamp at creation time */
61 u32 rcv_wnd; /* rcv_wnd offered first time */
62 u32 ts_recent;
63 unsigned long expires;
64 const struct request_sock_ops *rsk_ops;
65 struct sock *sk;
66 u32 secid;
67 u32 peer_secid;
68};
69
70static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
71{
72 struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
73
74 if (req != NULL)
75 req->rsk_ops = ops;
76
77 return req;
78}
79
80static inline void __reqsk_free(struct request_sock *req)
81{
82 kmem_cache_free(req->rsk_ops->slab, req);
83}
84
85static inline void reqsk_free(struct request_sock *req)
86{
87 req->rsk_ops->destructor(req);
88 __reqsk_free(req);
89}
90
91extern int sysctl_max_syn_backlog;
92
93/** struct listen_sock - listen state
94 *
95 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
96 */
97struct listen_sock {
98 u8 max_qlen_log;
99 u8 synflood_warned;
100 /* 2 bytes hole, try to use */
101 int qlen;
102 int qlen_young;
103 int clock_hand;
104 u32 hash_rnd;
105 u32 nr_table_entries;
106 struct request_sock *syn_table[0];
107};
108
109/** struct request_sock_queue - queue of request_socks
110 *
111 * @rskq_accept_head - FIFO head of established children
112 * @rskq_accept_tail - FIFO tail of established children
113 * @rskq_defer_accept - User waits for some data after accept()
114 * @syn_wait_lock - serializer
115 *
116 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
117 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
118 *
119 * This lock is acquired in read mode only from listening_get_next() seq_file
120 * op and it's acquired in write mode _only_ from code that is actively
121 * changing rskq_accept_head. All readers that are holding the master sock lock
122 * don't need to grab this lock in read mode too as rskq_accept_head. writes
123 * are always protected from the main sock lock.
124 */
125struct request_sock_queue {
126 struct request_sock *rskq_accept_head;
127 struct request_sock *rskq_accept_tail;
128 rwlock_t syn_wait_lock;
129 u8 rskq_defer_accept;
130 /* 3 bytes hole, try to pack */
131 struct listen_sock *listen_opt;
132};
133
134extern int reqsk_queue_alloc(struct request_sock_queue *queue,
135 unsigned int nr_table_entries);
136
137extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
138extern void reqsk_queue_destroy(struct request_sock_queue *queue);
139
140static inline struct request_sock *
141 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
142{
143 struct request_sock *req = queue->rskq_accept_head;
144
145 queue->rskq_accept_head = NULL;
146 return req;
147}
148
149static inline int reqsk_queue_empty(struct request_sock_queue *queue)
150{
151 return queue->rskq_accept_head == NULL;
152}
153
154static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
155 struct request_sock *req,
156 struct request_sock **prev_req)
157{
158 write_lock(&queue->syn_wait_lock);
159 *prev_req = req->dl_next;
160 write_unlock(&queue->syn_wait_lock);
161}
162
163static inline void reqsk_queue_add(struct request_sock_queue *queue,
164 struct request_sock *req,
165 struct sock *parent,
166 struct sock *child)
167{
168 req->sk = child;
169 sk_acceptq_added(parent);
170
171 if (queue->rskq_accept_head == NULL)
172 queue->rskq_accept_head = req;
173 else
174 queue->rskq_accept_tail->dl_next = req;
175
176 queue->rskq_accept_tail = req;
177 req->dl_next = NULL;
178}
179
180static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
181{
182 struct request_sock *req = queue->rskq_accept_head;
183
184 WARN_ON(req == NULL);
185
186 queue->rskq_accept_head = req->dl_next;
187 if (queue->rskq_accept_head == NULL)
188 queue->rskq_accept_tail = NULL;
189
190 return req;
191}
192
193static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
194 struct sock *parent)
195{
196 struct request_sock *req = reqsk_queue_remove(queue);
197 struct sock *child = req->sk;
198
199 WARN_ON(child == NULL);
200
201 sk_acceptq_removed(parent);
202 __reqsk_free(req);
203 return child;
204}
205
206static inline int reqsk_queue_removed(struct request_sock_queue *queue,
207 struct request_sock *req)
208{
209 struct listen_sock *lopt = queue->listen_opt;
210
211 if (req->retrans == 0)
212 --lopt->qlen_young;
213
214 return --lopt->qlen;
215}
216
217static inline int reqsk_queue_added(struct request_sock_queue *queue)
218{
219 struct listen_sock *lopt = queue->listen_opt;
220 const int prev_qlen = lopt->qlen;
221
222 lopt->qlen_young++;
223 lopt->qlen++;
224 return prev_qlen;
225}
226
227static inline int reqsk_queue_len(const struct request_sock_queue *queue)
228{
229 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
230}
231
232static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
233{
234 return queue->listen_opt->qlen_young;
235}
236
237static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
238{
239 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
240}
241
242static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
243 u32 hash, struct request_sock *req,
244 unsigned long timeout)
245{
246 struct listen_sock *lopt = queue->listen_opt;
247
248 req->expires = jiffies + timeout;
249 req->retrans = 0;
250 req->sk = NULL;
251 req->dl_next = lopt->syn_table[hash];
252
253 write_lock(&queue->syn_wait_lock);
254 lopt->syn_table[hash] = req;
255 write_unlock(&queue->syn_wait_lock);
256}
257
258#endif /* _REQUEST_SOCK_H */
1/*
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>
19#include <linux/spinlock.h>
20#include <linux/types.h>
21#include <linux/bug.h>
22
23#include <net/sock.h>
24
25struct request_sock;
26struct sk_buff;
27struct dst_entry;
28struct proto;
29
30struct request_sock_ops {
31 int family;
32 int obj_size;
33 struct kmem_cache *slab;
34 char *slab_name;
35 int (*rtx_syn_ack)(struct sock *sk,
36 struct request_sock *req);
37 void (*send_ack)(struct sock *sk, struct sk_buff *skb,
38 struct request_sock *req);
39 void (*send_reset)(struct sock *sk,
40 struct sk_buff *skb);
41 void (*destructor)(struct request_sock *req);
42 void (*syn_ack_timeout)(struct sock *sk,
43 struct request_sock *req);
44};
45
46int inet_rtx_syn_ack(struct sock *parent, struct request_sock *req);
47
48/* struct request_sock - mini sock to represent a connection request
49 */
50struct request_sock {
51 struct sock_common __req_common;
52 struct request_sock *dl_next;
53 u16 mss;
54 u8 num_retrans; /* number of retransmits */
55 u8 cookie_ts:1; /* syncookie: encode tcpopts in timestamp */
56 u8 num_timeout:7; /* number of timeouts */
57 /* The following two fields can be easily recomputed I think -AK */
58 u32 window_clamp; /* window clamp at creation time */
59 u32 rcv_wnd; /* rcv_wnd offered first time */
60 u32 ts_recent;
61 unsigned long expires;
62 const struct request_sock_ops *rsk_ops;
63 struct sock *sk;
64 u32 secid;
65 u32 peer_secid;
66};
67
68static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
69{
70 struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
71
72 if (req != NULL)
73 req->rsk_ops = ops;
74
75 return req;
76}
77
78static inline void __reqsk_free(struct request_sock *req)
79{
80 kmem_cache_free(req->rsk_ops->slab, req);
81}
82
83static inline void reqsk_free(struct request_sock *req)
84{
85 req->rsk_ops->destructor(req);
86 __reqsk_free(req);
87}
88
89extern int sysctl_max_syn_backlog;
90
91/** struct listen_sock - listen state
92 *
93 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
94 */
95struct listen_sock {
96 u8 max_qlen_log;
97 u8 synflood_warned;
98 /* 2 bytes hole, try to use */
99 int qlen;
100 int qlen_young;
101 int clock_hand;
102 u32 hash_rnd;
103 u32 nr_table_entries;
104 struct request_sock *syn_table[0];
105};
106
107/*
108 * For a TCP Fast Open listener -
109 * lock - protects the access to all the reqsk, which is co-owned by
110 * the listener and the child socket.
111 * qlen - pending TFO requests (still in TCP_SYN_RECV).
112 * max_qlen - max TFO reqs allowed before TFO is disabled.
113 *
114 * XXX (TFO) - ideally these fields can be made as part of "listen_sock"
115 * structure above. But there is some implementation difficulty due to
116 * listen_sock being part of request_sock_queue hence will be freed when
117 * a listener is stopped. But TFO related fields may continue to be
118 * accessed even after a listener is closed, until its sk_refcnt drops
119 * to 0 implying no more outstanding TFO reqs. One solution is to keep
120 * listen_opt around until sk_refcnt drops to 0. But there is some other
121 * complexity that needs to be resolved. E.g., a listener can be disabled
122 * temporarily through shutdown()->tcp_disconnect(), and re-enabled later.
123 */
124struct fastopen_queue {
125 struct request_sock *rskq_rst_head; /* Keep track of past TFO */
126 struct request_sock *rskq_rst_tail; /* requests that caused RST.
127 * This is part of the defense
128 * against spoofing attack.
129 */
130 spinlock_t lock;
131 int qlen; /* # of pending (TCP_SYN_RECV) reqs */
132 int max_qlen; /* != 0 iff TFO is currently enabled */
133};
134
135/** struct request_sock_queue - queue of request_socks
136 *
137 * @rskq_accept_head - FIFO head of established children
138 * @rskq_accept_tail - FIFO tail of established children
139 * @rskq_defer_accept - User waits for some data after accept()
140 * @syn_wait_lock - serializer
141 *
142 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
143 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
144 *
145 * This lock is acquired in read mode only from listening_get_next() seq_file
146 * op and it's acquired in write mode _only_ from code that is actively
147 * changing rskq_accept_head. All readers that are holding the master sock lock
148 * don't need to grab this lock in read mode too as rskq_accept_head. writes
149 * are always protected from the main sock lock.
150 */
151struct request_sock_queue {
152 struct request_sock *rskq_accept_head;
153 struct request_sock *rskq_accept_tail;
154 rwlock_t syn_wait_lock;
155 u8 rskq_defer_accept;
156 /* 3 bytes hole, try to pack */
157 struct listen_sock *listen_opt;
158 struct fastopen_queue *fastopenq; /* This is non-NULL iff TFO has been
159 * enabled on this listener. Check
160 * max_qlen != 0 in fastopen_queue
161 * to determine if TFO is enabled
162 * right at this moment.
163 */
164};
165
166int reqsk_queue_alloc(struct request_sock_queue *queue,
167 unsigned int nr_table_entries);
168
169void __reqsk_queue_destroy(struct request_sock_queue *queue);
170void reqsk_queue_destroy(struct request_sock_queue *queue);
171void reqsk_fastopen_remove(struct sock *sk, struct request_sock *req,
172 bool reset);
173
174static inline struct request_sock *
175 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
176{
177 struct request_sock *req = queue->rskq_accept_head;
178
179 queue->rskq_accept_head = NULL;
180 return req;
181}
182
183static inline int reqsk_queue_empty(struct request_sock_queue *queue)
184{
185 return queue->rskq_accept_head == NULL;
186}
187
188static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
189 struct request_sock *req,
190 struct request_sock **prev_req)
191{
192 write_lock(&queue->syn_wait_lock);
193 *prev_req = req->dl_next;
194 write_unlock(&queue->syn_wait_lock);
195}
196
197static inline void reqsk_queue_add(struct request_sock_queue *queue,
198 struct request_sock *req,
199 struct sock *parent,
200 struct sock *child)
201{
202 req->sk = child;
203 sk_acceptq_added(parent);
204
205 if (queue->rskq_accept_head == NULL)
206 queue->rskq_accept_head = req;
207 else
208 queue->rskq_accept_tail->dl_next = req;
209
210 queue->rskq_accept_tail = req;
211 req->dl_next = NULL;
212}
213
214static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
215{
216 struct request_sock *req = queue->rskq_accept_head;
217
218 WARN_ON(req == NULL);
219
220 queue->rskq_accept_head = req->dl_next;
221 if (queue->rskq_accept_head == NULL)
222 queue->rskq_accept_tail = NULL;
223
224 return req;
225}
226
227static inline int reqsk_queue_removed(struct request_sock_queue *queue,
228 struct request_sock *req)
229{
230 struct listen_sock *lopt = queue->listen_opt;
231
232 if (req->num_timeout == 0)
233 --lopt->qlen_young;
234
235 return --lopt->qlen;
236}
237
238static inline int reqsk_queue_added(struct request_sock_queue *queue)
239{
240 struct listen_sock *lopt = queue->listen_opt;
241 const int prev_qlen = lopt->qlen;
242
243 lopt->qlen_young++;
244 lopt->qlen++;
245 return prev_qlen;
246}
247
248static inline int reqsk_queue_len(const struct request_sock_queue *queue)
249{
250 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
251}
252
253static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
254{
255 return queue->listen_opt->qlen_young;
256}
257
258static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
259{
260 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
261}
262
263static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
264 u32 hash, struct request_sock *req,
265 unsigned long timeout)
266{
267 struct listen_sock *lopt = queue->listen_opt;
268
269 req->expires = jiffies + timeout;
270 req->num_retrans = 0;
271 req->num_timeout = 0;
272 req->sk = NULL;
273 req->dl_next = lopt->syn_table[hash];
274
275 write_lock(&queue->syn_wait_lock);
276 lopt->syn_table[hash] = req;
277 write_unlock(&queue->syn_wait_lock);
278}
279
280#endif /* _REQUEST_SOCK_H */