Linux 2.6.26-rc5
[linux-2.6/openmoko-kernel/knife-kernel.git] / include / net / request_sock.h
blobb220b5f624de2cb97c60ba5c9453633f8d24be8c
1 /*
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>
22 #include <net/sock.h>
24 struct request_sock;
25 struct sk_buff;
26 struct dst_entry;
27 struct proto;
29 struct request_sock_ops {
30 int family;
31 int obj_size;
32 struct kmem_cache *slab;
33 int (*rtx_syn_ack)(struct sock *sk,
34 struct request_sock *req);
35 void (*send_ack)(struct sk_buff *skb,
36 struct request_sock *req);
37 void (*send_reset)(struct sock *sk,
38 struct sk_buff *skb);
39 void (*destructor)(struct request_sock *req);
42 /* struct request_sock - mini sock to represent a connection request
44 struct request_sock {
45 struct request_sock *dl_next; /* Must be first member! */
46 u16 mss;
47 u8 retrans;
48 u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
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;
54 const struct request_sock_ops *rsk_ops;
55 struct sock *sk;
56 u32 secid;
57 u32 peer_secid;
60 static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
62 struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
64 if (req != NULL)
65 req->rsk_ops = ops;
67 return req;
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);
78 __reqsk_free(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
87 struct listen_sock {
88 u8 max_qlen_log;
89 /* 3 bytes hole, try to use */
90 int qlen;
91 int qlen_young;
92 int clock_hand;
93 u32 hash_rnd;
94 u32 nr_table_entries;
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 u16 rskq_defer_accept;
119 /* 2 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 extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
127 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
129 static inline struct request_sock *
130 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
132 struct request_sock *req = queue->rskq_accept_head;
134 queue->rskq_accept_head = NULL;
135 return req;
138 static inline int reqsk_queue_empty(struct request_sock_queue *queue)
140 return queue->rskq_accept_head == NULL;
143 static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
144 struct request_sock *req,
145 struct request_sock **prev_req)
147 write_lock(&queue->syn_wait_lock);
148 *prev_req = req->dl_next;
149 write_unlock(&queue->syn_wait_lock);
152 static inline void reqsk_queue_add(struct request_sock_queue *queue,
153 struct request_sock *req,
154 struct sock *parent,
155 struct sock *child)
157 req->sk = child;
158 sk_acceptq_added(parent);
160 if (queue->rskq_accept_head == NULL)
161 queue->rskq_accept_head = req;
162 else
163 queue->rskq_accept_tail->dl_next = req;
165 queue->rskq_accept_tail = req;
166 req->dl_next = NULL;
169 static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
171 struct request_sock *req = queue->rskq_accept_head;
173 BUG_TRAP(req != NULL);
175 queue->rskq_accept_head = req->dl_next;
176 if (queue->rskq_accept_head == NULL)
177 queue->rskq_accept_tail = NULL;
179 return req;
182 static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
183 struct sock *parent)
185 struct request_sock *req = reqsk_queue_remove(queue);
186 struct sock *child = req->sk;
188 BUG_TRAP(child != NULL);
190 sk_acceptq_removed(parent);
191 __reqsk_free(req);
192 return child;
195 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
196 struct request_sock *req)
198 struct listen_sock *lopt = queue->listen_opt;
200 if (req->retrans == 0)
201 --lopt->qlen_young;
203 return --lopt->qlen;
206 static inline int reqsk_queue_added(struct request_sock_queue *queue)
208 struct listen_sock *lopt = queue->listen_opt;
209 const int prev_qlen = lopt->qlen;
211 lopt->qlen_young++;
212 lopt->qlen++;
213 return prev_qlen;
216 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
218 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
221 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
223 return queue->listen_opt->qlen_young;
226 static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
228 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
231 static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
232 u32 hash, struct request_sock *req,
233 unsigned long timeout)
235 struct listen_sock *lopt = queue->listen_opt;
237 req->expires = jiffies + timeout;
238 req->retrans = 0;
239 req->sk = NULL;
240 req->dl_next = lopt->syn_table[hash];
242 write_lock(&queue->syn_wait_lock);
243 lopt->syn_table[hash] = req;
244 write_unlock(&queue->syn_wait_lock);
247 #endif /* _REQUEST_SOCK_H */