2 * NET Generic infrastructure for Network protocols.
4 * Definitions for request_sock
6 * Authors: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
8 * From code originally in include/net/tcp.h
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.
15 #ifndef _REQUEST_SOCK_H
16 #define _REQUEST_SOCK_H
18 #include <linux/slab.h>
19 #include <linux/spinlock.h>
20 #include <linux/types.h>
29 struct request_sock_ops {
33 int (*rtx_syn_ack)(struct sock *sk,
34 struct request_sock *req,
35 struct dst_entry *dst);
36 void (*send_ack)(struct sk_buff *skb,
37 struct request_sock *req);
38 void (*send_reset)(struct sk_buff *skb);
39 void (*destructor)(struct request_sock *req);
42 /* struct request_sock - mini sock to represent a connection request
45 struct request_sock *dl_next; /* Must be first member! */
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 */
53 unsigned long expires;
54 const struct request_sock_ops *rsk_ops;
60 static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
62 struct request_sock *req = kmem_cache_alloc(ops->slab, SLAB_ATOMIC);
70 static inline void __reqsk_free(struct request_sock *req)
72 kmem_cache_free(req->rsk_ops->slab, req);
75 static inline void reqsk_free(struct request_sock *req)
77 req->rsk_ops->destructor(req);
81 extern int sysctl_max_syn_backlog;
83 /** struct listen_sock - listen state
85 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
89 /* 3 bytes hole, try to use */
95 struct request_sock *syn_table[0];
98 /** struct request_sock_queue - queue of request_socks
100 * @rskq_accept_head - FIFO head of established children
101 * @rskq_accept_tail - FIFO tail of established children
102 * @rskq_defer_accept - User waits for some data after accept()
103 * @syn_wait_lock - serializer
105 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
106 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
108 * This lock is acquired in read mode only from listening_get_next() seq_file
109 * op and it's acquired in write mode _only_ from code that is actively
110 * changing rskq_accept_head. All readers that are holding the master sock lock
111 * don't need to grab this lock in read mode too as rskq_accept_head. writes
112 * are always protected from the main sock lock.
114 struct request_sock_queue {
115 struct request_sock *rskq_accept_head;
116 struct request_sock *rskq_accept_tail;
117 rwlock_t syn_wait_lock;
118 u8 rskq_defer_accept;
119 /* 3 bytes hole, try to pack */
120 struct listen_sock *listen_opt;
123 extern int reqsk_queue_alloc(struct request_sock_queue *queue,
124 unsigned int nr_table_entries);
126 static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue)
128 struct listen_sock *lopt;
130 write_lock_bh(&queue->syn_wait_lock);
131 lopt = queue->listen_opt;
132 queue->listen_opt = NULL;
133 write_unlock_bh(&queue->syn_wait_lock);
138 static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
140 kfree(reqsk_queue_yank_listen_sk(queue));
143 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
145 static inline struct request_sock *
146 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
148 struct request_sock *req = queue->rskq_accept_head;
150 queue->rskq_accept_head = NULL;
154 static inline int reqsk_queue_empty(struct request_sock_queue *queue)
156 return queue->rskq_accept_head == NULL;
159 static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
160 struct request_sock *req,
161 struct request_sock **prev_req)
163 write_lock(&queue->syn_wait_lock);
164 *prev_req = req->dl_next;
165 write_unlock(&queue->syn_wait_lock);
168 static inline void reqsk_queue_add(struct request_sock_queue *queue,
169 struct request_sock *req,
174 sk_acceptq_added(parent);
176 if (queue->rskq_accept_head == NULL)
177 queue->rskq_accept_head = req;
179 queue->rskq_accept_tail->dl_next = req;
181 queue->rskq_accept_tail = req;
185 static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
187 struct request_sock *req = queue->rskq_accept_head;
189 BUG_TRAP(req != NULL);
191 queue->rskq_accept_head = req->dl_next;
192 if (queue->rskq_accept_head == NULL)
193 queue->rskq_accept_tail = NULL;
198 static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
201 struct request_sock *req = reqsk_queue_remove(queue);
202 struct sock *child = req->sk;
204 BUG_TRAP(child != NULL);
206 sk_acceptq_removed(parent);
211 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
212 struct request_sock *req)
214 struct listen_sock *lopt = queue->listen_opt;
216 if (req->retrans == 0)
222 static inline int reqsk_queue_added(struct request_sock_queue *queue)
224 struct listen_sock *lopt = queue->listen_opt;
225 const int prev_qlen = lopt->qlen;
232 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
234 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
237 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
239 return queue->listen_opt->qlen_young;
242 static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
244 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
247 static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
248 u32 hash, struct request_sock *req,
249 unsigned long timeout)
251 struct listen_sock *lopt = queue->listen_opt;
253 req->expires = jiffies + timeout;
256 req->dl_next = lopt->syn_table[hash];
258 write_lock(&queue->syn_wait_lock);
259 lopt->syn_table[hash] = req;
260 write_unlock(&queue->syn_wait_lock);
263 #endif /* _REQUEST_SOCK_H */