net: Fix memory leak in the proto_register function
[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 #include <linux/bug.h>
22
23 #include <net/sock.h>
24
25 struct request_sock;
26 struct sk_buff;
27 struct dst_entry;
28 struct proto;
29
30 struct request_sock_ops {
31         int             family;
32         int             obj_size;
33         struct kmem_cache       *slab;
34         char            *slab_name;
35         int             (*rtx_syn_ack)(struct sock *sk,
36                                        struct request_sock *req);
37         void            (*send_ack)(struct sock *sk, struct sk_buff *skb,
38                                     struct request_sock *req);
39         void            (*send_reset)(struct sock *sk,
40                                       struct sk_buff *skb);
41         void            (*destructor)(struct request_sock *req);
42 };
43
44 /* struct request_sock - mini sock to represent a connection request
45  */
46 struct request_sock {
47         struct request_sock             *dl_next; /* Must be first member! */
48         u16                             mss;
49         u8                              retrans;
50         u8                              cookie_ts; /* syncookie: encode tcpopts in timestamp */
51         /* The following two fields can be easily recomputed I think -AK */
52         u32                             window_clamp; /* window clamp at creation time */
53         u32                             rcv_wnd;          /* rcv_wnd offered first time */
54         u32                             ts_recent;
55         unsigned long                   expires;
56         const struct request_sock_ops   *rsk_ops;
57         struct sock                     *sk;
58         u32                             secid;
59         u32                             peer_secid;
60 };
61
62 static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
63 {
64         struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
65
66         if (req != NULL)
67                 req->rsk_ops = ops;
68
69         return req;
70 }
71
72 static inline void __reqsk_free(struct request_sock *req)
73 {
74         kmem_cache_free(req->rsk_ops->slab, req);
75 }
76
77 static inline void reqsk_free(struct request_sock *req)
78 {
79         req->rsk_ops->destructor(req);
80         __reqsk_free(req);
81 }
82
83 extern int sysctl_max_syn_backlog;
84
85 /** struct listen_sock - listen state
86  *
87  * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
88  */
89 struct listen_sock {
90         u8                      max_qlen_log;
91         /* 3 bytes hole, try to use */
92         int                     qlen;
93         int                     qlen_young;
94         int                     clock_hand;
95         u32                     hash_rnd;
96         u32                     nr_table_entries;
97         struct request_sock     *syn_table[0];
98 };
99
100 /** struct request_sock_queue - queue of request_socks
101  *
102  * @rskq_accept_head - FIFO head of established children
103  * @rskq_accept_tail - FIFO tail of established children
104  * @rskq_defer_accept - User waits for some data after accept()
105  * @syn_wait_lock - serializer
106  *
107  * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
108  * lock sock while browsing the listening hash (otherwise it's deadlock prone).
109  *
110  * This lock is acquired in read mode only from listening_get_next() seq_file
111  * op and it's acquired in write mode _only_ from code that is actively
112  * changing rskq_accept_head. All readers that are holding the master sock lock
113  * don't need to grab this lock in read mode too as rskq_accept_head. writes
114  * are always protected from the main sock lock.
115  */
116 struct request_sock_queue {
117         struct request_sock     *rskq_accept_head;
118         struct request_sock     *rskq_accept_tail;
119         rwlock_t                syn_wait_lock;
120         u8                      rskq_defer_accept;
121         /* 3 bytes hole, try to pack */
122         struct listen_sock      *listen_opt;
123 };
124
125 extern int reqsk_queue_alloc(struct request_sock_queue *queue,
126                              unsigned int nr_table_entries);
127
128 extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
129 extern void reqsk_queue_destroy(struct request_sock_queue *queue);
130
131 static inline struct request_sock *
132         reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
133 {
134         struct request_sock *req = queue->rskq_accept_head;
135
136         queue->rskq_accept_head = NULL;
137         return req;
138 }
139
140 static inline int reqsk_queue_empty(struct request_sock_queue *queue)
141 {
142         return queue->rskq_accept_head == NULL;
143 }
144
145 static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
146                                       struct request_sock *req,
147                                       struct request_sock **prev_req)
148 {
149         write_lock(&queue->syn_wait_lock);
150         *prev_req = req->dl_next;
151         write_unlock(&queue->syn_wait_lock);
152 }
153
154 static inline void reqsk_queue_add(struct request_sock_queue *queue,
155                                    struct request_sock *req,
156                                    struct sock *parent,
157                                    struct sock *child)
158 {
159         req->sk = child;
160         sk_acceptq_added(parent);
161
162         if (queue->rskq_accept_head == NULL)
163                 queue->rskq_accept_head = req;
164         else
165                 queue->rskq_accept_tail->dl_next = req;
166
167         queue->rskq_accept_tail = req;
168         req->dl_next = NULL;
169 }
170
171 static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
172 {
173         struct request_sock *req = queue->rskq_accept_head;
174
175         WARN_ON(req == NULL);
176
177         queue->rskq_accept_head = req->dl_next;
178         if (queue->rskq_accept_head == NULL)
179                 queue->rskq_accept_tail = NULL;
180
181         return req;
182 }
183
184 static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
185                                                  struct sock *parent)
186 {
187         struct request_sock *req = reqsk_queue_remove(queue);
188         struct sock *child = req->sk;
189
190         WARN_ON(child == NULL);
191
192         sk_acceptq_removed(parent);
193         __reqsk_free(req);
194         return child;
195 }
196
197 static inline int reqsk_queue_removed(struct request_sock_queue *queue,
198                                       struct request_sock *req)
199 {
200         struct listen_sock *lopt = queue->listen_opt;
201
202         if (req->retrans == 0)
203                 --lopt->qlen_young;
204
205         return --lopt->qlen;
206 }
207
208 static inline int reqsk_queue_added(struct request_sock_queue *queue)
209 {
210         struct listen_sock *lopt = queue->listen_opt;
211         const int prev_qlen = lopt->qlen;
212
213         lopt->qlen_young++;
214         lopt->qlen++;
215         return prev_qlen;
216 }
217
218 static inline int reqsk_queue_len(const struct request_sock_queue *queue)
219 {
220         return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
221 }
222
223 static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
224 {
225         return queue->listen_opt->qlen_young;
226 }
227
228 static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
229 {
230         return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
231 }
232
233 static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
234                                         u32 hash, struct request_sock *req,
235                                         unsigned long timeout)
236 {
237         struct listen_sock *lopt = queue->listen_opt;
238
239         req->expires = jiffies + timeout;
240         req->retrans = 0;
241         req->sk = NULL;
242         req->dl_next = lopt->syn_table[hash];
243
244         write_lock(&queue->syn_wait_lock);
245         lopt->syn_table[hash] = req;
246         write_unlock(&queue->syn_wait_lock);
247 }
248
249 #endif /* _REQUEST_SOCK_H */