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>
21 #include <linux/bug.h>
30 /* empty to "strongly type" an otherwise void parameter.
32 struct request_values {
35 struct request_sock_ops {
38 struct kmem_cache *slab;
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,
47 void (*destructor)(struct request_sock *req);
50 /* struct request_sock - mini sock to represent a connection request
53 struct request_sock *dl_next; /* Must be first member! */
56 u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
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 */
61 unsigned long expires;
62 const struct request_sock_ops *rsk_ops;
68 static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
70 struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
78 static inline void __reqsk_free(struct request_sock *req)
80 kmem_cache_free(req->rsk_ops->slab, req);
83 static inline void reqsk_free(struct request_sock *req)
85 req->rsk_ops->destructor(req);
89 extern int sysctl_max_syn_backlog;
91 /** struct listen_sock - listen state
93 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
97 /* 3 bytes hole, try to use */
102 u32 nr_table_entries;
103 struct request_sock *syn_table[0];
106 /** struct request_sock_queue - queue of request_socks
108 * @rskq_accept_head - FIFO head of established children
109 * @rskq_accept_tail - FIFO tail of established children
110 * @rskq_defer_accept - User waits for some data after accept()
111 * @syn_wait_lock - serializer
113 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
114 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
116 * This lock is acquired in read mode only from listening_get_next() seq_file
117 * op and it's acquired in write mode _only_ from code that is actively
118 * changing rskq_accept_head. All readers that are holding the master sock lock
119 * don't need to grab this lock in read mode too as rskq_accept_head. writes
120 * are always protected from the main sock lock.
122 struct request_sock_queue {
123 struct request_sock *rskq_accept_head;
124 struct request_sock *rskq_accept_tail;
125 rwlock_t syn_wait_lock;
126 u8 rskq_defer_accept;
127 /* 3 bytes hole, try to pack */
128 struct listen_sock *listen_opt;
131 extern int reqsk_queue_alloc(struct request_sock_queue *queue,
132 unsigned int nr_table_entries);
134 extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
135 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
137 static inline struct request_sock *
138 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
140 struct request_sock *req = queue->rskq_accept_head;
142 queue->rskq_accept_head = NULL;
146 static inline int reqsk_queue_empty(struct request_sock_queue *queue)
148 return queue->rskq_accept_head == NULL;
151 static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
152 struct request_sock *req,
153 struct request_sock **prev_req)
155 write_lock(&queue->syn_wait_lock);
156 *prev_req = req->dl_next;
157 write_unlock(&queue->syn_wait_lock);
160 static inline void reqsk_queue_add(struct request_sock_queue *queue,
161 struct request_sock *req,
166 sk_acceptq_added(parent);
168 if (queue->rskq_accept_head == NULL)
169 queue->rskq_accept_head = req;
171 queue->rskq_accept_tail->dl_next = req;
173 queue->rskq_accept_tail = req;
177 static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
179 struct request_sock *req = queue->rskq_accept_head;
181 WARN_ON(req == NULL);
183 queue->rskq_accept_head = req->dl_next;
184 if (queue->rskq_accept_head == NULL)
185 queue->rskq_accept_tail = NULL;
190 static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
193 struct request_sock *req = reqsk_queue_remove(queue);
194 struct sock *child = req->sk;
196 WARN_ON(child == NULL);
198 sk_acceptq_removed(parent);
203 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
204 struct request_sock *req)
206 struct listen_sock *lopt = queue->listen_opt;
208 if (req->retrans == 0)
214 static inline int reqsk_queue_added(struct request_sock_queue *queue)
216 struct listen_sock *lopt = queue->listen_opt;
217 const int prev_qlen = lopt->qlen;
224 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
226 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
229 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
231 return queue->listen_opt->qlen_young;
234 static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
236 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
239 static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
240 u32 hash, struct request_sock *req,
241 unsigned long timeout)
243 struct listen_sock *lopt = queue->listen_opt;
245 req->expires = jiffies + timeout;
248 req->dl_next = lopt->syn_table[hash];
250 write_lock(&queue->syn_wait_lock);
251 lopt->syn_table[hash] = req;
252 write_unlock(&queue->syn_wait_lock);
255 #endif /* _REQUEST_SOCK_H */