[deliverable/linux.git] / include / net / request_sock.h

/*
 * NET		Generic infrastructure for Network protocols.
 *
 *		Definitions for request_sock 
 *
 * Authors:	Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 * 		From code originally in include/net/tcp.h
 *
 *		This program is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 */
#ifndef _REQUEST_SOCK_H
#define _REQUEST_SOCK_H

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/bug.h>

#include <net/sock.h>

struct request_sock;
struct sk_buff;
struct dst_entry;
struct proto;

/* empty to "strongly type" an otherwise void parameter.
 */
struct request_values {
};

struct request_sock_ops {
	int		family;
	int		obj_size;
	struct kmem_cache	*slab;
	char		*slab_name;
	int		(*rtx_syn_ack)(struct sock *sk,
				       struct request_sock *req,
				       struct request_values *rvp);
	void		(*send_ack)(struct sock *sk, struct sk_buff *skb,
				    struct request_sock *req);
	void		(*send_reset)(struct sock *sk,
				      struct sk_buff *skb);
	void		(*destructor)(struct request_sock *req);
};

/* struct request_sock - mini sock to represent a connection request
 */
struct request_sock {
	struct request_sock		*dl_next; /* Must be first member! */
	u16				mss;
	u8				retrans;
	u8				cookie_ts; /* syncookie: encode tcpopts in timestamp */
	/* The following two fields can be easily recomputed I think -AK */
	u32				window_clamp; /* window clamp at creation time */
	u32				rcv_wnd;	  /* rcv_wnd offered first time */
	u32				ts_recent;
	unsigned long			expires;
	const struct request_sock_ops	*rsk_ops;
	struct sock			*sk;
	u32				secid;
	u32				peer_secid;
};

static inline struct request_sock *reqsk_alloc(const struct request_sock_ops *ops)
{
	struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);

	if (req != NULL)
		req->rsk_ops = ops;

	return req;
}

static inline void __reqsk_free(struct request_sock *req)
{
	kmem_cache_free(req->rsk_ops->slab, req);
}

static inline void reqsk_free(struct request_sock *req)
{
	req->rsk_ops->destructor(req);
	__reqsk_free(req);
}

extern int sysctl_max_syn_backlog;

/** struct listen_sock - listen state
 *
 * @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
 */
struct listen_sock {
	u8			max_qlen_log;
	/* 3 bytes hole, try to use */
	int			qlen;
	int			qlen_young;
	int			clock_hand;
	u32			hash_rnd;
	u32			nr_table_entries;
	struct request_sock	*syn_table[0];
};

/** struct request_sock_queue - queue of request_socks
 *
 * @rskq_accept_head - FIFO head of established children
 * @rskq_accept_tail - FIFO tail of established children
 * @rskq_defer_accept - User waits for some data after accept()
 * @syn_wait_lock - serializer
 *
 * %syn_wait_lock is necessary only to avoid proc interface having to grab the main
 * lock sock while browsing the listening hash (otherwise it's deadlock prone).
 *
 * This lock is acquired in read mode only from listening_get_next() seq_file
 * op and it's acquired in write mode _only_ from code that is actively
 * changing rskq_accept_head. All readers that are holding the master sock lock
 * don't need to grab this lock in read mode too as rskq_accept_head. writes
 * are always protected from the main sock lock.
 */
struct request_sock_queue {
	struct request_sock	*rskq_accept_head;
	struct request_sock	*rskq_accept_tail;
	rwlock_t		syn_wait_lock;
	u8			rskq_defer_accept;
	/* 3 bytes hole, try to pack */
	struct listen_sock	*listen_opt;
};

extern int reqsk_queue_alloc(struct request_sock_queue *queue,
			     unsigned int nr_table_entries);

extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
extern void reqsk_queue_destroy(struct request_sock_queue *queue);

static inline struct request_sock *
	reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
{
	struct request_sock *req = queue->rskq_accept_head;

	queue->rskq_accept_head = NULL;
	return req;
}

static inline int reqsk_queue_empty(struct request_sock_queue *queue)
{
	return queue->rskq_accept_head == NULL;
}

static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
				      struct request_sock *req,
				      struct request_sock **prev_req)
{
	write_lock(&queue->syn_wait_lock);
	*prev_req = req->dl_next;
	write_unlock(&queue->syn_wait_lock);
}

static inline void reqsk_queue_add(struct request_sock_queue *queue,
				   struct request_sock *req,
				   struct sock *parent,
				   struct sock *child)
{
	req->sk = child;
	sk_acceptq_added(parent);

	if (queue->rskq_accept_head == NULL)
		queue->rskq_accept_head = req;
	else
		queue->rskq_accept_tail->dl_next = req;

	queue->rskq_accept_tail = req;
	req->dl_next = NULL;
}

static inline struct request_sock *reqsk_queue_remove(struct request_sock_queue *queue)
{
	struct request_sock *req = queue->rskq_accept_head;

	WARN_ON(req == NULL);

	queue->rskq_accept_head = req->dl_next;
	if (queue->rskq_accept_head == NULL)
		queue->rskq_accept_tail = NULL;

	return req;
}

static inline struct sock *reqsk_queue_get_child(struct request_sock_queue *queue,
						 struct sock *parent)
{
	struct request_sock *req = reqsk_queue_remove(queue);
	struct sock *child = req->sk;

	WARN_ON(child == NULL);

	sk_acceptq_removed(parent);
	__reqsk_free(req);
	return child;
}

static inline int reqsk_queue_removed(struct request_sock_queue *queue,
				      struct request_sock *req)
{
	struct listen_sock *lopt = queue->listen_opt;

	if (req->retrans == 0)
		--lopt->qlen_young;

	return --lopt->qlen;
}

static inline int reqsk_queue_added(struct request_sock_queue *queue)
{
	struct listen_sock *lopt = queue->listen_opt;
	const int prev_qlen = lopt->qlen;

	lopt->qlen_young++;
	lopt->qlen++;
	return prev_qlen;
}

static inline int reqsk_queue_len(const struct request_sock_queue *queue)
{
	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
}

static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
{
	return queue->listen_opt->qlen_young;
}

static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
{
	return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
}

static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
					u32 hash, struct request_sock *req,
					unsigned long timeout)
{
	struct listen_sock *lopt = queue->listen_opt;

	req->expires = jiffies + timeout;
	req->retrans = 0;
	req->sk = NULL;
	req->dl_next = lopt->syn_table[hash];

	write_lock(&queue->syn_wait_lock);
	lopt->syn_table[hash] = req;
	write_unlock(&queue->syn_wait_lock);
}

#endif /* _REQUEST_SOCK_H */
Commit	Line	Data
2e6599cb ACM	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>
0e87506f	19	#include <linux/spinlock.h>
2e6599cb	20	#include <linux/types.h>
547b792c	21	#include <linux/bug.h>
0e87506f	22
2e6599cb ACM	23	#include <net/sock.h>
2e6599cb ACM	24
60236fdd	25	struct request_sock;
2e6599cb ACM	26	struct sk_buff;
	27	struct dst_entry;
	28	struct proto;
	29
e6b4d113 WAS	30	/* empty to "strongly type" an otherwise void parameter.
	31	*/
	32	struct request_values {
	33	};
	34
60236fdd	35	struct request_sock_ops {
2e6599cb	36	int family;
2e6599cb	37	int obj_size;
e18b890b	38	struct kmem_cache *slab;
7e56b5d6	39	char *slab_name;
2e6599cb	40	int (rtx_syn_ack)(struct sock sk,
e6b4d113 WAS	41	struct request_sock *req,
e6b4d113 WAS	42	struct request_values *rvp);
6edafaaf	43	void (send_ack)(struct sock sk, struct sk_buff *skb,
60236fdd	44	struct request_sock *req);
cfb6eeb4 YH	45	void (send_reset)(struct sock sk,
cfb6eeb4 YH	46	struct sk_buff *skb);
60236fdd	47	void (destructor)(struct request_sock req);
2e6599cb ACM	48	};
2e6599cb ACM	49
60236fdd	50	/* struct request_sock - mini sock to represent a connection request
2e6599cb	51	*/
60236fdd ACM	52	struct request_sock {
60236fdd ACM	53	struct request_sock dl_next; / Must be first member! */
2e6599cb ACM	54	u16 mss;
2e6599cb ACM	55	u8 retrans;
4dfc2817	56	u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
2e6599cb ACM	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 */
	60	u32 ts_recent;
	61	unsigned long expires;
72a3effa	62	const struct request_sock_ops *rsk_ops;
2e6599cb	63	struct sock *sk;
4237c75c	64	u32 secid;
6b877699	65	u32 peer_secid;
2e6599cb ACM	66	};
2e6599cb ACM	67
72a3effa	68	static inline struct request_sock reqsk_alloc(const struct request_sock_ops ops)
2e6599cb	69	{
54e6ecb2	70	struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
2e6599cb ACM	71
2e6599cb ACM	72	if (req != NULL)
60236fdd	73	req->rsk_ops = ops;
2e6599cb ACM	74
	75	return req;
	76	}
	77
60236fdd	78	static inline void __reqsk_free(struct request_sock *req)
2e6599cb	79	{
60236fdd	80	kmem_cache_free(req->rsk_ops->slab, req);
2e6599cb ACM	81	}
2e6599cb ACM	82
60236fdd	83	static inline void reqsk_free(struct request_sock *req)
2e6599cb	84	{
60236fdd ACM	85	req->rsk_ops->destructor(req);
60236fdd ACM	86	__reqsk_free(req);
2e6599cb ACM	87	}
2e6599cb ACM	88
0e87506f ACM	89	extern int sysctl_max_syn_backlog;
0e87506f ACM	90
2ad69c55	91	/** struct listen_sock - listen state
0e87506f ACM	92	*
	93	* @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
	94	*/
2ad69c55	95	struct listen_sock {
0e87506f ACM	96	u8 max_qlen_log;
	97	/* 3 bytes hole, try to use */
	98	int qlen;
	99	int qlen_young;
	100	int clock_hand;
	101	u32 hash_rnd;
83e3609e	102	u32 nr_table_entries;
0e87506f ACM	103	struct request_sock *syn_table[0];
	104	};
	105
	106	/** struct request_sock_queue - queue of request_socks
	107	*
	108	* @rskq_accept_head - FIFO head of established children
	109	* @rskq_accept_tail - FIFO tail of established children
295f7324	110	* @rskq_defer_accept - User waits for some data after accept()
0e87506f ACM	111	* @syn_wait_lock - serializer
	112	*
	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).
	115	*
	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.
	121	*/
	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;
ec0a1966 DM	126	u8 rskq_defer_accept;
ec0a1966 DM	127	/* 3 bytes hole, try to pack */
2ad69c55	128	struct listen_sock *listen_opt;
0e87506f ACM	129	};
	130
	131	extern int reqsk_queue_alloc(struct request_sock_queue *queue,
72a3effa	132	unsigned int nr_table_entries);
0e87506f	133
dab6ba36	134	extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
83e3609e ACM	135	extern void reqsk_queue_destroy(struct request_sock_queue *queue);
83e3609e ACM	136
0e87506f ACM	137	static inline struct request_sock *
	138	reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
	139	{
	140	struct request_sock *req = queue->rskq_accept_head;
	141
3eb4801d	142	queue->rskq_accept_head = NULL;
0e87506f ACM	143	return req;
	144	}
	145
	146	static inline int reqsk_queue_empty(struct request_sock_queue *queue)
	147	{
	148	return queue->rskq_accept_head == NULL;
	149	}
	150
	151	static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
	152	struct request_sock *req,
	153	struct request_sock **prev_req)
	154	{
	155	write_lock(&queue->syn_wait_lock);
	156	*prev_req = req->dl_next;
	157	write_unlock(&queue->syn_wait_lock);
	158	}
	159
	160	static inline void reqsk_queue_add(struct request_sock_queue *queue,
	161	struct request_sock *req,
	162	struct sock *parent,
	163	struct sock *child)
	164	{
	165	req->sk = child;
	166	sk_acceptq_added(parent);
	167
	168	if (queue->rskq_accept_head == NULL)
	169	queue->rskq_accept_head = req;
	170	else
	171	queue->rskq_accept_tail->dl_next = req;
	172
	173	queue->rskq_accept_tail = req;
	174	req->dl_next = NULL;
	175	}
	176
	177	static inline struct request_sock reqsk_queue_remove(struct request_sock_queue queue)
	178	{
	179	struct request_sock *req = queue->rskq_accept_head;
	180
547b792c	181	WARN_ON(req == NULL);
0e87506f ACM	182
	183	queue->rskq_accept_head = req->dl_next;
	184	if (queue->rskq_accept_head == NULL)
	185	queue->rskq_accept_tail = NULL;
	186
	187	return req;
	188	}
	189
	190	static inline struct sock reqsk_queue_get_child(struct request_sock_queue queue,
	191	struct sock *parent)
	192	{
	193	struct request_sock *req = reqsk_queue_remove(queue);
	194	struct sock *child = req->sk;
	195
547b792c	196	WARN_ON(child == NULL);
0e87506f ACM	197
	198	sk_acceptq_removed(parent);
	199	__reqsk_free(req);
	200	return child;
	201	}
	202
	203	static inline int reqsk_queue_removed(struct request_sock_queue *queue,
	204	struct request_sock *req)
	205	{
2ad69c55	206	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	207
	208	if (req->retrans == 0)
	209	--lopt->qlen_young;
	210
	211	return --lopt->qlen;
	212	}
	213
	214	static inline int reqsk_queue_added(struct request_sock_queue *queue)
	215	{
2ad69c55	216	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	217	const int prev_qlen = lopt->qlen;
	218
	219	lopt->qlen_young++;
	220	lopt->qlen++;
	221	return prev_qlen;
	222	}
	223
463c84b9	224	static inline int reqsk_queue_len(const struct request_sock_queue *queue)
0e87506f ACM	225	{
	226	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
	227	}
	228
463c84b9	229	static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
0e87506f ACM	230	{
	231	return queue->listen_opt->qlen_young;
	232	}
	233
463c84b9	234	static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
0e87506f ACM	235	{
	236	return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
	237	}
	238
	239	static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
	240	u32 hash, struct request_sock *req,
8129765a	241	unsigned long timeout)
0e87506f	242	{
2ad69c55	243	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	244
	245	req->expires = jiffies + timeout;
	246	req->retrans = 0;
	247	req->sk = NULL;
	248	req->dl_next = lopt->syn_table[hash];
	249
	250	write_lock(&queue->syn_wait_lock);
	251	lopt->syn_table[hash] = req;
	252	write_unlock(&queue->syn_wait_lock);
	253	}
	254
2e6599cb	255	#endif /* _REQUEST_SOCK_H */