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 struct request_sock_ops *rsk_ops;
58 static inline struct request_sock *reqsk_alloc(struct request_sock_ops *ops)
60 struct request_sock *req = kmem_cache_alloc(ops->slab, SLAB_ATOMIC);
68 static inline void __reqsk_free(struct request_sock *req)
70 kmem_cache_free(req->rsk_ops->slab, req);
73 static inline void reqsk_free(struct request_sock *req)
75 req->rsk_ops->destructor(req);
79 extern int sysctl_max_syn_backlog;
81 /** struct listen_sock - listen state
83 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
87 /* 3 bytes hole, try to use */
93 struct request_sock *syn_table[0];
96 /** struct request_sock_queue - queue of request_socks
98 * @rskq_accept_head - FIFO head of established children
99 * @rskq_accept_tail - FIFO tail of established children
100 * @syn_wait_lock - serializer
102 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
103 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
105 * This lock is acquired in read mode only from listening_get_next() seq_file
106 * op and it's acquired in write mode _only_ from code that is actively
107 * changing rskq_accept_head. All readers that are holding the master sock lock
108 * don't need to grab this lock in read mode too as rskq_accept_head. writes
109 * are always protected from the main sock lock.
111 struct request_sock_queue {
112 struct request_sock *rskq_accept_head;
113 struct request_sock *rskq_accept_tail;
114 rwlock_t syn_wait_lock;
115 struct listen_sock *listen_opt;
118 extern int reqsk_queue_alloc(struct request_sock_queue *queue,
119 const int nr_table_entries);
121 static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue)
123 struct listen_sock *lopt;
125 write_lock_bh(&queue->syn_wait_lock);
126 lopt = queue->listen_opt;
127 queue->listen_opt = NULL;
128 write_unlock_bh(&queue->syn_wait_lock);
133 static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
135 kfree(reqsk_queue_yank_listen_sk(queue));
138 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
140 static inline struct request_sock *
141 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
143 struct request_sock *req = queue->rskq_accept_head;
145 queue->rskq_accept_head = queue->rskq_accept_head = NULL;
149 static inline int reqsk_queue_empty(struct request_sock_queue *queue)
151 return queue->rskq_accept_head == NULL;
154 static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
155 struct request_sock *req,
156 struct request_sock **prev_req)
158 write_lock(&queue->syn_wait_lock);
159 *prev_req = req->dl_next;
160 write_unlock(&queue->syn_wait_lock);
163 static inline void reqsk_queue_add(struct request_sock_queue *queue,
164 struct request_sock *req,
169 sk_acceptq_added(parent);
171 if (queue->rskq_accept_head == NULL)
172 queue->rskq_accept_head = req;
174 queue->rskq_accept_tail->dl_next = req;
176 queue->rskq_accept_tail = req;
180 static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
182 struct request_sock *req = queue->rskq_accept_head;
184 BUG_TRAP(req != NULL);
186 queue->rskq_accept_head = req->dl_next;
187 if (queue->rskq_accept_head == NULL)
188 queue->rskq_accept_tail = NULL;
193 static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
196 struct request_sock *req = reqsk_queue_remove(queue);
197 struct sock *child = req->sk;
199 BUG_TRAP(child != NULL);
201 sk_acceptq_removed(parent);
206 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
207 struct request_sock *req)
209 struct listen_sock *lopt = queue->listen_opt;
211 if (req->retrans == 0)
217 static inline int reqsk_queue_added(struct request_sock_queue *queue)
219 struct listen_sock *lopt = queue->listen_opt;
220 const int prev_qlen = lopt->qlen;
227 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
229 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
232 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
234 return queue->listen_opt->qlen_young;
237 static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
239 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
242 static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
243 u32 hash, struct request_sock *req,
246 struct listen_sock *lopt = queue->listen_opt;
248 req->expires = jiffies + timeout;
251 req->dl_next = lopt->syn_table[hash];
253 write_lock(&queue->syn_wait_lock);
254 lopt->syn_table[hash] = req;
255 write_unlock(&queue->syn_wait_lock);
258 #endif /* _REQUEST_SOCK_H */