[mirror_ubuntu-artful-kernel.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 <net/sock.h>

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

struct request_sock_ops {
	int		family;
	int		obj_size;
	struct kmem_cache	*slab;
	int		(*rtx_syn_ack)(struct sock *sk,
				       struct request_sock *req);
	void		(*send_ack)(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;

	BUG_TRAP(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;

	BUG_TRAP(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>
0e87506f	21
2e6599cb ACM	22	#include <net/sock.h>
2e6599cb ACM	23
60236fdd	24	struct request_sock;
2e6599cb ACM	25	struct sk_buff;
	26	struct dst_entry;
	27	struct proto;
	28
60236fdd	29	struct request_sock_ops {
2e6599cb	30	int family;
2e6599cb	31	int obj_size;
e18b890b	32	struct kmem_cache *slab;
2e6599cb	33	int (rtx_syn_ack)(struct sock sk,
fd80eb94	34	struct request_sock *req);
2e6599cb	35	void (send_ack)(struct sk_buff skb,
60236fdd	36	struct request_sock *req);
cfb6eeb4 YH	37	void (send_reset)(struct sock sk,
cfb6eeb4 YH	38	struct sk_buff *skb);
60236fdd	39	void (destructor)(struct request_sock req);
2e6599cb ACM	40	};
2e6599cb ACM	41
60236fdd	42	/* struct request_sock - mini sock to represent a connection request
2e6599cb	43	*/
60236fdd ACM	44	struct request_sock {
60236fdd ACM	45	struct request_sock dl_next; / Must be first member! */
2e6599cb ACM	46	u16 mss;
2e6599cb ACM	47	u8 retrans;
4dfc2817	48	u8 cookie_ts; /* syncookie: encode tcpopts in timestamp */
2e6599cb ACM	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;
72a3effa	54	const struct request_sock_ops *rsk_ops;
2e6599cb	55	struct sock *sk;
4237c75c	56	u32 secid;
6b877699	57	u32 peer_secid;
2e6599cb ACM	58	};
2e6599cb ACM	59
72a3effa	60	static inline struct request_sock reqsk_alloc(const struct request_sock_ops ops)
2e6599cb	61	{
54e6ecb2	62	struct request_sock *req = kmem_cache_alloc(ops->slab, GFP_ATOMIC);
2e6599cb ACM	63
2e6599cb ACM	64	if (req != NULL)
60236fdd	65	req->rsk_ops = ops;
2e6599cb ACM	66
	67	return req;
	68	}
	69
60236fdd	70	static inline void __reqsk_free(struct request_sock *req)
2e6599cb	71	{
60236fdd	72	kmem_cache_free(req->rsk_ops->slab, req);
2e6599cb ACM	73	}
2e6599cb ACM	74
60236fdd	75	static inline void reqsk_free(struct request_sock *req)
2e6599cb	76	{
60236fdd ACM	77	req->rsk_ops->destructor(req);
60236fdd ACM	78	__reqsk_free(req);
2e6599cb ACM	79	}
2e6599cb ACM	80
0e87506f ACM	81	extern int sysctl_max_syn_backlog;
0e87506f ACM	82
2ad69c55	83	/** struct listen_sock - listen state
0e87506f ACM	84	*
	85	* @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
	86	*/
2ad69c55	87	struct listen_sock {
0e87506f ACM	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;
83e3609e	94	u32 nr_table_entries;
0e87506f ACM	95	struct request_sock *syn_table[0];
	96	};
	97
	98	/** struct request_sock_queue - queue of request_socks
	99	*
	100	* @rskq_accept_head - FIFO head of established children
	101	* @rskq_accept_tail - FIFO tail of established children
295f7324	102	* @rskq_defer_accept - User waits for some data after accept()
0e87506f ACM	103	* @syn_wait_lock - serializer
	104	*
	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).
	107	*
	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.
	113	*/
	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;
ec0a1966 DM	118	u8 rskq_defer_accept;
ec0a1966 DM	119	/* 3 bytes hole, try to pack */
2ad69c55	120	struct listen_sock *listen_opt;
0e87506f ACM	121	};
	122
	123	extern int reqsk_queue_alloc(struct request_sock_queue *queue,
72a3effa	124	unsigned int nr_table_entries);
0e87506f	125
dab6ba36	126	extern void __reqsk_queue_destroy(struct request_sock_queue *queue);
83e3609e ACM	127	extern void reqsk_queue_destroy(struct request_sock_queue *queue);
83e3609e ACM	128
0e87506f ACM	129	static inline struct request_sock *
	130	reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
	131	{
	132	struct request_sock *req = queue->rskq_accept_head;
	133
3eb4801d	134	queue->rskq_accept_head = NULL;
0e87506f ACM	135	return req;
	136	}
	137
	138	static inline int reqsk_queue_empty(struct request_sock_queue *queue)
	139	{
	140	return queue->rskq_accept_head == NULL;
	141	}
	142
	143	static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
	144	struct request_sock *req,
	145	struct request_sock **prev_req)
	146	{
	147	write_lock(&queue->syn_wait_lock);
	148	*prev_req = req->dl_next;
	149	write_unlock(&queue->syn_wait_lock);
	150	}
	151
	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)
	156	{
	157	req->sk = child;
	158	sk_acceptq_added(parent);
	159
	160	if (queue->rskq_accept_head == NULL)
	161	queue->rskq_accept_head = req;
	162	else
	163	queue->rskq_accept_tail->dl_next = req;
	164
	165	queue->rskq_accept_tail = req;
	166	req->dl_next = NULL;
	167	}
	168
	169	static inline struct request_sock reqsk_queue_remove(struct request_sock_queue queue)
	170	{
	171	struct request_sock *req = queue->rskq_accept_head;
	172
	173	BUG_TRAP(req != NULL);
	174
	175	queue->rskq_accept_head = req->dl_next;
	176	if (queue->rskq_accept_head == NULL)
	177	queue->rskq_accept_tail = NULL;
	178
	179	return req;
	180	}
	181
	182	static inline struct sock reqsk_queue_get_child(struct request_sock_queue queue,
	183	struct sock *parent)
	184	{
	185	struct request_sock *req = reqsk_queue_remove(queue);
	186	struct sock *child = req->sk;
	187
	188	BUG_TRAP(child != NULL);
	189
	190	sk_acceptq_removed(parent);
	191	__reqsk_free(req);
	192	return child;
	193	}
	194
	195	static inline int reqsk_queue_removed(struct request_sock_queue *queue,
	196	struct request_sock *req)
	197	{
2ad69c55	198	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	199
	200	if (req->retrans == 0)
	201	--lopt->qlen_young;
	202
	203	return --lopt->qlen;
	204	}
	205
	206	static inline int reqsk_queue_added(struct request_sock_queue *queue)
	207	{
2ad69c55	208	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	209	const int prev_qlen = lopt->qlen;
	210
	211	lopt->qlen_young++;
	212	lopt->qlen++;
	213	return prev_qlen;
	214	}
	215
463c84b9	216	static inline int reqsk_queue_len(const struct request_sock_queue *queue)
0e87506f ACM	217	{
	218	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
	219	}
	220
463c84b9	221	static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
0e87506f ACM	222	{
	223	return queue->listen_opt->qlen_young;
	224	}
	225
463c84b9	226	static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
0e87506f ACM	227	{
	228	return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
	229	}
	230
	231	static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
	232	u32 hash, struct request_sock *req,
8129765a	233	unsigned long timeout)
0e87506f	234	{
2ad69c55	235	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	236
	237	req->expires = jiffies + timeout;
	238	req->retrans = 0;
	239	req->sk = NULL;
	240	req->dl_next = lopt->syn_table[hash];
	241
	242	write_lock(&queue->syn_wait_lock);
	243	lopt->syn_table[hash] = req;
	244	write_unlock(&queue->syn_wait_lock);
	245	}
	246
2e6599cb	247	#endif /* _REQUEST_SOCK_H */