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Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -07001/*
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>
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070019#include <linux/spinlock.h>
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070020#include <linux/types.h>
Ilpo Järvinen547b7922008-07-25 21:43:18 -070021#include <linux/bug.h>
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070022
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070023#include <net/sock.h>
24
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070025struct request_sock;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070026struct sk_buff;
27struct dst_entry;
28struct proto;
29
William Allen Simpsone6b4d112009-12-02 18:07:39 +000030/* empty to "strongly type" an otherwise void parameter.
31 */
32struct request_values {
33};
34
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070035struct request_sock_ops {
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070036 int family;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070037 int obj_size;
Christoph Lametere18b8902006-12-06 20:33:20 -080038 struct kmem_cache *slab;
Catalin Marinas7e56b5d2008-11-21 16:45:22 -080039 char *slab_name;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070040 int (*rtx_syn_ack)(struct sock *sk,
William Allen Simpsone6b4d112009-12-02 18:07:39 +000041 struct request_sock *req,
42 struct request_values *rvp);
Gui Jianfeng6edafaa2008-08-06 23:50:04 -070043 void (*send_ack)(struct sock *sk, struct sk_buff *skb,
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070044 struct request_sock *req);
YOSHIFUJI Hideakicfb6eeb2006-11-14 19:07:45 -080045 void (*send_reset)(struct sock *sk,
46 struct sk_buff *skb);
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070047 void (*destructor)(struct request_sock *req);
Octavian Purdila72659ec2010-01-17 19:09:39 -080048 void (*syn_ack_timeout)(struct sock *sk,
49 struct request_sock *req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070050};
51
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070052/* struct request_sock - mini sock to represent a connection request
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070053 */
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070054struct request_sock {
55 struct request_sock *dl_next; /* Must be first member! */
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070056 u16 mss;
57 u8 retrans;
Florian Westphal4dfc2812008-04-10 03:12:40 -070058 u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070059 /* The following two fields can be easily recomputed I think -AK */
60 u32 window_clamp; /* window clamp at creation time */
61 u32 rcv_wnd; /* rcv_wnd offered first time */
62 u32 ts_recent;
63 unsigned long expires;
Eric Dumazet72a3eff2006-11-16 02:30:37 -080064 const struct request_sock_ops *rsk_ops;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070065 struct sock *sk;
Venkat Yekkirala4237c752006-07-24 23:32:50 -070066 u32 secid;
Venkat Yekkirala6b877692006-11-08 17:04:09 -060067 u32 peer_secid;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070068};
69
Eric Dumazet72a3eff2006-11-16 02:30:37 -080070static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070071{
Christoph Lameter54e6ecb2006-12-06 20:33:16 -080072 struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070073
74 if (req != NULL)
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070075 req->rsk_ops = ops;
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070076
77 return req;
78}
79
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070080static inline void __reqsk_free(struct request_sock *req)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070081{
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070082 kmem_cache_free(req->rsk_ops->slab, req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070083}
84
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070085static inline void reqsk_free(struct request_sock *req)
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070086{
Arnaldo Carvalho de Melo60236fd2005-06-18 22:47:21 -070087 req->rsk_ops->destructor(req);
88 __reqsk_free(req);
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -070089}
90
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070091extern int sysctl_max_syn_backlog;
92
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -070093/** struct listen_sock - listen state
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070094 *
95 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
96 */
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -070097struct listen_sock {
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -070098 u8 max_qlen_log;
99 /* 3 bytes hole, try to use */
100 int qlen;
101 int qlen_young;
102 int clock_hand;
103 u32 hash_rnd;
Arnaldo Carvalho de Melo83e36092005-08-09 19:33:31 -0700104 u32 nr_table_entries;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700105 struct request_sock *syn_table[0];
106};
107
108/** struct request_sock_queue - queue of request_socks
109 *
110 * @rskq_accept_head - FIFO head of established children
111 * @rskq_accept_tail - FIFO tail of established children
Arnaldo Carvalho de Melo295f7322005-08-09 20:11:56 -0700112 * @rskq_defer_accept - User waits for some data after accept()
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700113 * @syn_wait_lock - serializer
114 *
115 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
116 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
117 *
118 * This lock is acquired in read mode only from listening_get_next() seq_file
119 * op and it's acquired in write mode _only_ from code that is actively
120 * changing rskq_accept_head. All readers that are holding the master sock lock
121 * don't need to grab this lock in read mode too as rskq_accept_head. writes
122 * are always protected from the main sock lock.
123 */
124struct request_sock_queue {
125 struct request_sock *rskq_accept_head;
126 struct request_sock *rskq_accept_tail;
127 rwlock_t syn_wait_lock;
David S. Millerec0a1962008-06-12 16:31:35 -0700128 u8 rskq_defer_accept;
129 /* 3 bytes hole, try to pack */
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700130 struct listen_sock *listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700131};
132
133extern int reqsk_queue_alloc(struct request_sock_queue *queue,
Eric Dumazet72a3eff2006-11-16 02:30:37 -0800134 unsigned int nr_table_entries);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700135
Pavel Emelyanovdab6ba32007-11-15 02:57:06 -0800136extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
Arnaldo Carvalho de Melo83e36092005-08-09 19:33:31 -0700137extern void reqsk_queue_destroy(struct request_sock_queue *queue);
138
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700139static inline struct request_sock *
140 reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
141{
142 struct request_sock *req = queue->rskq_accept_head;
143
Norbert Kiesel3eb48012006-03-26 17:39:55 -0800144 queue->rskq_accept_head = NULL;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700145 return req;
146}
147
148static inline int reqsk_queue_empty(struct request_sock_queue *queue)
149{
150 return queue->rskq_accept_head == NULL;
151}
152
153static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
154 struct request_sock *req,
155 struct request_sock **prev_req)
156{
157 write_lock(&queue->syn_wait_lock);
158 *prev_req = req->dl_next;
159 write_unlock(&queue->syn_wait_lock);
160}
161
162static inline void reqsk_queue_add(struct request_sock_queue *queue,
163 struct request_sock *req,
164 struct sock *parent,
165 struct sock *child)
166{
167 req->sk = child;
168 sk_acceptq_added(parent);
169
170 if (queue->rskq_accept_head == NULL)
171 queue->rskq_accept_head = req;
172 else
173 queue->rskq_accept_tail->dl_next = req;
174
175 queue->rskq_accept_tail = req;
176 req->dl_next = NULL;
177}
178
179static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
180{
181 struct request_sock *req = queue->rskq_accept_head;
182
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700183 WARN_ON(req == NULL);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700184
185 queue->rskq_accept_head = req->dl_next;
186 if (queue->rskq_accept_head == NULL)
187 queue->rskq_accept_tail = NULL;
188
189 return req;
190}
191
192static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
193 struct sock *parent)
194{
195 struct request_sock *req = reqsk_queue_remove(queue);
196 struct sock *child = req->sk;
197
Ilpo Järvinen547b7922008-07-25 21:43:18 -0700198 WARN_ON(child == NULL);
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700199
200 sk_acceptq_removed(parent);
201 __reqsk_free(req);
202 return child;
203}
204
205static inline int reqsk_queue_removed(struct request_sock_queue *queue,
206 struct request_sock *req)
207{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700208 struct listen_sock *lopt = queue->listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700209
210 if (req->retrans == 0)
211 --lopt->qlen_young;
212
213 return --lopt->qlen;
214}
215
216static inline int reqsk_queue_added(struct request_sock_queue *queue)
217{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700218 struct listen_sock *lopt = queue->listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700219 const int prev_qlen = lopt->qlen;
220
221 lopt->qlen_young++;
222 lopt->qlen++;
223 return prev_qlen;
224}
225
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700226static inline int reqsk_queue_len(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700227{
228 return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
229}
230
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700231static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700232{
233 return queue->listen_opt->qlen_young;
234}
235
Arnaldo Carvalho de Melo463c84b2005-08-09 20:10:42 -0700236static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700237{
238 return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
239}
240
241static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
242 u32 hash, struct request_sock *req,
Arnaldo Carvalho de Melo81297652005-12-13 23:15:24 -0800243 unsigned long timeout)
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700244{
Arnaldo Carvalho de Melo2ad69c52005-06-18 22:48:55 -0700245 struct listen_sock *lopt = queue->listen_opt;
Arnaldo Carvalho de Melo0e875062005-06-18 22:47:59 -0700246
247 req->expires = jiffies + timeout;
248 req->retrans = 0;
249 req->sk = NULL;
250 req->dl_next = lopt->syn_table[hash];
251
252 write_lock(&queue->syn_wait_lock);
253 lopt->syn_table[hash] = req;
254 write_unlock(&queue->syn_wait_lock);
255}
256
Arnaldo Carvalho de Melo2e6599c2005-06-18 22:46:52 -0700257#endif /* _REQUEST_SOCK_H */