[PATCH] slab: remove kmem_cache_t
[linux-3.10.git] / include / net / request_sock.h
1 /*
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>
19 #include <linux/spinlock.h>
20 #include <linux/types.h>
21
22 #include <net/sock.h>
23
24 struct request_sock;
25 struct sk_buff;
26 struct dst_entry;
27 struct proto;
28
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                                        struct dst_entry *dst);
36         void            (*send_ack)(struct sk_buff *skb,
37                                     struct request_sock *req);
38         void            (*send_reset)(struct sock *sk,
39                                       struct sk_buff *skb);
40         void            (*destructor)(struct request_sock *req);
41 };
42
43 /* struct request_sock - mini sock to represent a connection request
44  */
45 struct request_sock {
46         struct request_sock             *dl_next; /* Must be first member! */
47         u16                             mss;
48         u8                              retrans;
49         u8                              __pad;
50         /* The following two fields can be easily recomputed I think -AK */
51         u32                             window_clamp; /* window clamp at creation time */
52         u32                             rcv_wnd;          /* rcv_wnd offered first time */
53         u32                             ts_recent;
54         unsigned long                   expires;
55         const struct request_sock_ops   *rsk_ops;
56         struct sock                     *sk;
57         u32                             secid;
58         u32                             peer_secid;
59 };
60
61 static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
62 {
63         struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
64
65         if (req != NULL)
66                 req->rsk_ops = ops;
67
68         return req;
69 }
70
71 static inline void __reqsk_free(struct request_sock *req)
72 {
73         kmem_cache_free(req->rsk_ops->slab, req);
74 }
75
76 static inline void reqsk_free(struct request_sock *req)
77 {
78         req->rsk_ops->destructor(req);
79         __reqsk_free(req);
80 }
81
82 extern int sysctl_max_syn_backlog;
83
84 /** struct listen_sock - listen state
85  *
86  * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
87  */
88 struct listen_sock {
89         u8                      max_qlen_log;
90         /* 3 bytes hole, try to use */
91         int                     qlen;
92         int                     qlen_young;
93         int                     clock_hand;
94         u32                     hash_rnd;
95         u32                     nr_table_entries;
96         struct request_sock     *syn_table[0];
97 };
98
99 /** struct request_sock_queue - queue of request_socks
100  *
101  * @rskq_accept_head - FIFO head of established children
102  * @rskq_accept_tail - FIFO tail of established children
103  * @rskq_defer_accept - User waits for some data after accept()
104  * @syn_wait_lock - serializer
105  *
106  * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
107  * lock sock while browsing the listening hash (otherwise it's deadlock prone).
108  *
109  * This lock is acquired in read mode only from listening_get_next() seq_file
110  * op and it's acquired in write mode _only_ from code that is actively
111  * changing rskq_accept_head. All readers that are holding the master sock lock
112  * don't need to grab this lock in read mode too as rskq_accept_head. writes
113  * are always protected from the main sock lock.
114  */
115 struct request_sock_queue {
116         struct request_sock     *rskq_accept_head;
117         struct request_sock     *rskq_accept_tail;
118         rwlock_t                syn_wait_lock;
119         u8                      rskq_defer_accept;
120         /* 3 bytes hole, try to pack */
121         struct listen_sock      *listen_opt;
122 };
123
124 extern int reqsk_queue_alloc(struct request_sock_queue *queue,
125                              unsigned int nr_table_entries);
126
127 static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue)
128 {
129         struct listen_sock *lopt;
130
131         write_lock_bh(&queue->syn_wait_lock);
132         lopt = queue->listen_opt;
133         queue->listen_opt = NULL;
134         write_unlock_bh(&queue->syn_wait_lock);
135
136         return lopt;
137 }
138
139 static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
140 {
141         kfree(reqsk_queue_yank_listen_sk(queue));
142 }
143
144 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
145
146 static inline struct request_sock *
147         reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
148 {
149         struct request_sock *req = queue->rskq_accept_head;
150
151         queue->rskq_accept_head = NULL;
152         return req;
153 }
154
155 static inline int reqsk_queue_empty(struct request_sock_queue *queue)
156 {
157         return queue->rskq_accept_head == NULL;
158 }
159
160 static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
161                                       struct request_sock *req,
162                                       struct request_sock **prev_req)
163 {
164         write_lock(&queue->syn_wait_lock);
165         *prev_req = req->dl_next;
166         write_unlock(&queue->syn_wait_lock);
167 }
168
169 static inline void reqsk_queue_add(struct request_sock_queue *queue,
170                                    struct request_sock *req,
171                                    struct sock *parent,
172                                    struct sock *child)
173 {
174         req->sk = child;
175         sk_acceptq_added(parent);
176
177         if (queue->rskq_accept_head == NULL)
178                 queue->rskq_accept_head = req;
179         else
180                 queue->rskq_accept_tail->dl_next = req;
181
182         queue->rskq_accept_tail = req;
183         req->dl_next = NULL;
184 }
185
186 static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
187 {
188         struct request_sock *req = queue->rskq_accept_head;
189
190         BUG_TRAP(req != NULL);
191
192         queue->rskq_accept_head = req->dl_next;
193         if (queue->rskq_accept_head == NULL)
194                 queue->rskq_accept_tail = NULL;
195
196         return req;
197 }
198
199 static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
200                                                  struct sock *parent)
201 {
202         struct request_sock *req = reqsk_queue_remove(queue);
203         struct sock *child = req->sk;
204
205         BUG_TRAP(child != NULL);
206
207         sk_acceptq_removed(parent);
208         __reqsk_free(req);
209         return child;
210 }
211
212 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
213                                       struct request_sock *req)
214 {
215         struct listen_sock *lopt = queue->listen_opt;
216
217         if (req->retrans == 0)
218                 --lopt->qlen_young;
219
220         return --lopt->qlen;
221 }
222
223 static inline int reqsk_queue_added(struct request_sock_queue *queue)
224 {
225         struct listen_sock *lopt = queue->listen_opt;
226         const int prev_qlen = lopt->qlen;
227
228         lopt->qlen_young++;
229         lopt->qlen++;
230         return prev_qlen;
231 }
232
233 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
234 {
235         return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
236 }
237
238 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
239 {
240         return queue->listen_opt->qlen_young;
241 }
242
243 static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
244 {
245         return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
246 }
247
248 static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
249                                         u32 hash, struct request_sock *req,
250                                         unsigned long timeout)
251 {
252         struct listen_sock *lopt = queue->listen_opt;
253
254         req->expires = jiffies + timeout;
255         req->retrans = 0;
256         req->sk = NULL;
257         req->dl_next = lopt->syn_table[hash];
258
259         write_lock(&queue->syn_wait_lock);
260         lopt->syn_table[hash] = req;
261         write_unlock(&queue->syn_wait_lock);
262 }
263
264 #endif /* _REQUEST_SOCK_H */