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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>
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070021
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070022#include <net/sock.h>
23
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070024struct request_sock;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070025struct sk_buff;
26struct dst_entry;
27struct proto;
28
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070029struct request_sock_ops {
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070030 int family;
31 kmem_cache_t *slab;
32 int obj_size;
33 int (*rtx_syn_ack)(struct sock *sk,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070034 struct request_sock *req,
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070035 struct dst_entry *dst);
36 void (*send_ack)(struct sk_buff *skb,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070037 struct request_sock *req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070038 void (*send_reset)(struct sk_buff *skb);
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070039 void (*destructor)(struct request_sock *req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070040};
41
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070042/* struct request_sock - mini sock to represent a connection request
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070043 */
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070044struct request_sock {
45 struct request_sock *dl_next; /* Must be first member! */
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070046 u16 mss;
47 u8 retrans;
48 u8 __pad;
49 /* The following two fields can be easily recomputed I think -AK */
50 u32 window_clamp; /* window clamp at creation time */
51 u32 rcv_wnd; /* rcv_wnd offered first time */
52 u32 ts_recent;
53 unsigned long expires;
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070054 struct request_sock_ops *rsk_ops;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070055 struct sock *sk;
56};
57
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070058static inline struct request_sock *reqsk_alloc(struct request_sock_ops *ops)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070059{
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070060 struct request_sock *req = kmem_cache_alloc(ops->slab, SLAB_ATOMIC);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070061
62 if (req != NULL)
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070063 req->rsk_ops = ops;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070064
65 return req;
66}
67
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070068static inline void __reqsk_free(struct request_sock *req)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070069{
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070070 kmem_cache_free(req->rsk_ops->slab, req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070071}
72
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070073static inline void reqsk_free(struct request_sock *req)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070074{
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070075 req->rsk_ops->destructor(req);
76 __reqsk_free(req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070077}
78
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070079extern int sysctl_max_syn_backlog;
80
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -070081/** struct listen_sock - listen state
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070082 *
83 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
84 */
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -070085struct listen_sock {
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070086 u8 max_qlen_log;
87 /* 3 bytes hole, try to use */
88 int qlen;
89 int qlen_young;
90 int clock_hand;
91 u32 hash_rnd;
Arnaldo Carvalho de Melo83e36092005-08-09 19:33:31 -070092 u32 nr_table_entries;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070093 struct request_sock *syn_table[0];
94};
95
96/** struct request_sock_queue - queue of request_socks
97 *
98 * @rskq_accept_head - FIFO head of established children
99 * @rskq_accept_tail - FIFO tail of established children
Arnaldo Carvalho de Melo295f7322005-08-09 20:11:56 -0700100 * @rskq_defer_accept - User waits for some data after accept()
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700101 * @syn_wait_lock - serializer
102 *
103 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
104 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
105 *
106 * This lock is acquired in read mode only from listening_get_next() seq_file
107 * op and it's acquired in write mode _only_ from code that is actively
108 * changing rskq_accept_head. All readers that are holding the master sock lock
109 * don't need to grab this lock in read mode too as rskq_accept_head. writes
110 * are always protected from the main sock lock.
111 */
112struct request_sock_queue {
113 struct request_sock *rskq_accept_head;
114 struct request_sock *rskq_accept_tail;
115 rwlock_t syn_wait_lock;
Arnaldo Carvalho de Melo295f7322005-08-09 20:11:56 -0700116 u8 rskq_defer_accept;
117 /* 3 bytes hole, try to pack */
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700118 struct listen_sock *listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700119};
120
121extern int reqsk_queue_alloc(struct request_sock_queue *queue,
122 const int nr_table_entries);
123
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700124static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700125{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700126 struct listen_sock *lopt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700127
128 write_lock_bh(&queue->syn_wait_lock);
129 lopt = queue->listen_opt;
130 queue->listen_opt = NULL;
131 write_unlock_bh(&queue->syn_wait_lock);
132
133 return lopt;
134}
135
Arnaldo Carvalho de Melo83e36092005-08-09 19:33:31 -0700136static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700137{
138 kfree(reqsk_queue_yank_listen_sk(queue));
139}
140
Arnaldo Carvalho de Melo83e36092005-08-09 19:33:31 -0700141extern void reqsk_queue_destroy(struct request_sock_queue *queue);
142
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700143static inline struct request_sock *
144 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
145{
146 struct request_sock *req = queue->rskq_accept_head;
147
Norbert Kiesel3eb48012006-03-26 17:39:55 -0800148 queue->rskq_accept_head = NULL;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700149 return req;
150}
151
152static inline int reqsk_queue_empty(struct request_sock_queue *queue)
153{
154 return queue->rskq_accept_head == NULL;
155}
156
157static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
158 struct request_sock *req,
159 struct request_sock **prev_req)
160{
161 write_lock(&queue->syn_wait_lock);
162 *prev_req = req->dl_next;
163 write_unlock(&queue->syn_wait_lock);
164}
165
166static inline void reqsk_queue_add(struct request_sock_queue *queue,
167 struct request_sock *req,
168 struct sock *parent,
169 struct sock *child)
170{
171 req->sk = child;
172 sk_acceptq_added(parent);
173
174 if (queue->rskq_accept_head == NULL)
175 queue->rskq_accept_head = req;
176 else
177 queue->rskq_accept_tail->dl_next = req;
178
179 queue->rskq_accept_tail = req;
180 req->dl_next = NULL;
181}
182
183static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
184{
185 struct request_sock *req = queue->rskq_accept_head;
186
187 BUG_TRAP(req != NULL);
188
189 queue->rskq_accept_head = req->dl_next;
190 if (queue->rskq_accept_head == NULL)
191 queue->rskq_accept_tail = NULL;
192
193 return req;
194}
195
196static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
197 struct sock *parent)
198{
199 struct request_sock *req = reqsk_queue_remove(queue);
200 struct sock *child = req->sk;
201
202 BUG_TRAP(child != NULL);
203
204 sk_acceptq_removed(parent);
205 __reqsk_free(req);
206 return child;
207}
208
209static inline int reqsk_queue_removed(struct request_sock_queue *queue,
210 struct request_sock *req)
211{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700212 struct listen_sock *lopt = queue->listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700213
214 if (req->retrans == 0)
215 --lopt->qlen_young;
216
217 return --lopt->qlen;
218}
219
220static inline int reqsk_queue_added(struct request_sock_queue *queue)
221{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700222 struct listen_sock *lopt = queue->listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700223 const int prev_qlen = lopt->qlen;
224
225 lopt->qlen_young++;
226 lopt->qlen++;
227 return prev_qlen;
228}
229
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700230static inline int reqsk_queue_len(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700231{
232 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
233}
234
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700235static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700236{
237 return queue->listen_opt->qlen_young;
238}
239
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700240static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700241{
242 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
243}
244
245static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
246 u32 hash, struct request_sock *req,
Arnaldo Carvalho de Melo81297652005-12-13 23:15:24 -0800247 unsigned long timeout)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700248{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700249 struct listen_sock *lopt = queue->listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700250
251 req->expires = jiffies + timeout;
252 req->retrans = 0;
253 req->sk = NULL;
254 req->dl_next = lopt->syn_table[hash];
255
256 write_lock(&queue->syn_wait_lock);
257 lopt->syn_table[hash] = req;
258 write_unlock(&queue->syn_wait_lock);
259}
260
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -0700261#endif /* _REQUEST_SOCK_H */