[mirror_ubuntu-bionic-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;
	kmem_cache_t	*slab;
	int		obj_size;
	int		(*rtx_syn_ack)(struct sock *sk,
				       struct request_sock *req,
				       struct dst_entry *dst);
	void		(*send_ack)(struct sk_buff *skb,
				    struct request_sock *req);
	void		(*send_reset)(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				__pad;
	/* 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;
	struct request_sock_ops		*rsk_ops;
	struct sock			*sk;
};

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

static inline struct listen_sock *reqsk_queue_yank_listen_sk(struct request_sock_queue *queue)
{
	struct listen_sock *lopt;

	write_lock_bh(&queue->syn_wait_lock);
	lopt = queue->listen_opt;
	queue->listen_opt = NULL;
	write_unlock_bh(&queue->syn_wait_lock);

	return lopt;
}

static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
{
	kfree(reqsk_queue_yank_listen_sk(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 = 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 ACM	30	int family;
	31	kmem_cache_t *slab;
	32	int obj_size;
	33	int (rtx_syn_ack)(struct sock sk,
60236fdd	34	struct request_sock *req,
2e6599cb ACM	35	struct dst_entry *dst);
2e6599cb ACM	36	void (send_ack)(struct sk_buff skb,
60236fdd	37	struct request_sock *req);
2e6599cb	38	void (send_reset)(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;
	47	u8 retrans;
	48	u8 __pad;
	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;
60236fdd	54	struct request_sock_ops *rsk_ops;
2e6599cb ACM	55	struct sock *sk;
	56	};
	57
60236fdd	58	static inline struct request_sock reqsk_alloc(struct request_sock_ops ops)
2e6599cb	59	{
60236fdd	60	struct request_sock *req = kmem_cache_alloc(ops->slab, SLAB_ATOMIC);
2e6599cb ACM	61
2e6599cb ACM	62	if (req != NULL)
60236fdd	63	req->rsk_ops = ops;
2e6599cb ACM	64
	65	return req;
	66	}
	67
60236fdd	68	static inline void __reqsk_free(struct request_sock *req)
2e6599cb	69	{
60236fdd	70	kmem_cache_free(req->rsk_ops->slab, req);
2e6599cb ACM	71	}
2e6599cb ACM	72
60236fdd	73	static inline void reqsk_free(struct request_sock *req)
2e6599cb	74	{
60236fdd ACM	75	req->rsk_ops->destructor(req);
60236fdd ACM	76	__reqsk_free(req);
2e6599cb ACM	77	}
2e6599cb ACM	78
0e87506f ACM	79	extern int sysctl_max_syn_backlog;
0e87506f ACM	80
2ad69c55	81	/** struct listen_sock - listen state
0e87506f ACM	82	*
	83	* @max_qlen_log - log_2 of maximal queued SYNs/REQUESTs
	84	*/
2ad69c55	85	struct listen_sock {
0e87506f ACM	86	u8 max_qlen_log;
	87	/* 3 bytes hole, try to use */
	88	int qlen;
	89	int qlen_young;
	90	int clock_hand;
	91	u32 hash_rnd;
83e3609e	92	u32 nr_table_entries;
0e87506f ACM	93	struct request_sock *syn_table[0];
	94	};
	95
	96	/** struct request_sock_queue - queue of request_socks
	97	*
	98	* @rskq_accept_head - FIFO head of established children
	99	* @rskq_accept_tail - FIFO tail of established children
295f7324	100	* @rskq_defer_accept - User waits for some data after accept()
0e87506f ACM	101	* @syn_wait_lock - serializer
	102	*
	103	* %syn_wait_lock is necessary only to avoid proc interface having to grab the main
	104	* lock sock while browsing the listening hash (otherwise it's deadlock prone).
	105	*
	106	* This lock is acquired in read mode only from listening_get_next() seq_file
	107	* op and it's acquired in write mode _only_ from code that is actively
	108	* changing rskq_accept_head. All readers that are holding the master sock lock
	109	* don't need to grab this lock in read mode too as rskq_accept_head. writes
	110	* are always protected from the main sock lock.
	111	*/
	112	struct request_sock_queue {
	113	struct request_sock *rskq_accept_head;
	114	struct request_sock *rskq_accept_tail;
	115	rwlock_t syn_wait_lock;
295f7324 ACM	116	u8 rskq_defer_accept;
295f7324 ACM	117	/* 3 bytes hole, try to pack */
2ad69c55	118	struct listen_sock *listen_opt;
0e87506f ACM	119	};
	120
	121	extern int reqsk_queue_alloc(struct request_sock_queue *queue,
	122	const int nr_table_entries);
	123
2ad69c55	124	static inline struct listen_sock reqsk_queue_yank_listen_sk(struct request_sock_queue queue)
0e87506f	125	{
2ad69c55	126	struct listen_sock *lopt;
0e87506f ACM	127
	128	write_lock_bh(&queue->syn_wait_lock);
	129	lopt = queue->listen_opt;
	130	queue->listen_opt = NULL;
	131	write_unlock_bh(&queue->syn_wait_lock);
	132
	133	return lopt;
	134	}
	135
83e3609e	136	static inline void __reqsk_queue_destroy(struct request_sock_queue *queue)
0e87506f ACM	137	{
	138	kfree(reqsk_queue_yank_listen_sk(queue));
	139	}
	140
83e3609e ACM	141	extern void reqsk_queue_destroy(struct request_sock_queue *queue);
83e3609e ACM	142
0e87506f ACM	143	static inline struct request_sock *
	144	reqsk_queue_yank_acceptq(struct request_sock_queue *queue)
	145	{
	146	struct request_sock *req = queue->rskq_accept_head;
	147
	148	queue->rskq_accept_head = queue->rskq_accept_head = NULL;
	149	return req;
	150	}
	151
	152	static inline int reqsk_queue_empty(struct request_sock_queue *queue)
	153	{
	154	return queue->rskq_accept_head == NULL;
	155	}
	156
	157	static inline void reqsk_queue_unlink(struct request_sock_queue *queue,
	158	struct request_sock *req,
	159	struct request_sock **prev_req)
	160	{
	161	write_lock(&queue->syn_wait_lock);
	162	*prev_req = req->dl_next;
	163	write_unlock(&queue->syn_wait_lock);
	164	}
	165
	166	static inline void reqsk_queue_add(struct request_sock_queue *queue,
	167	struct request_sock *req,
	168	struct sock *parent,
	169	struct sock *child)
	170	{
	171	req->sk = child;
	172	sk_acceptq_added(parent);
	173
	174	if (queue->rskq_accept_head == NULL)
	175	queue->rskq_accept_head = req;
	176	else
	177	queue->rskq_accept_tail->dl_next = req;
	178
	179	queue->rskq_accept_tail = req;
	180	req->dl_next = NULL;
	181	}
	182
	183	static inline struct request_sock reqsk_queue_remove(struct request_sock_queue queue)
	184	{
	185	struct request_sock *req = queue->rskq_accept_head;
	186
	187	BUG_TRAP(req != NULL);
	188
	189	queue->rskq_accept_head = req->dl_next;
	190	if (queue->rskq_accept_head == NULL)
	191	queue->rskq_accept_tail = NULL;
	192
	193	return req;
	194	}
	195
	196	static inline struct sock reqsk_queue_get_child(struct request_sock_queue queue,
	197	struct sock *parent)
	198	{
	199	struct request_sock *req = reqsk_queue_remove(queue);
	200	struct sock *child = req->sk;
	201
	202	BUG_TRAP(child != NULL);
	203
	204	sk_acceptq_removed(parent);
	205	__reqsk_free(req);
	206	return child;
207	}
208
209	static inline int reqsk_queue_removed(struct request_sock_queue *queue,
210	struct request_sock *req)
211	{
2ad69c55	212	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	213
	214	if (req->retrans == 0)
	215	--lopt->qlen_young;
	216
	217	return --lopt->qlen;
	218	}
	219
	220	static inline int reqsk_queue_added(struct request_sock_queue *queue)
	221	{
2ad69c55	222	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	223	const int prev_qlen = lopt->qlen;
	224
	225	lopt->qlen_young++;
	226	lopt->qlen++;
	227	return prev_qlen;
	228	}
	229
463c84b9	230	static inline int reqsk_queue_len(const struct request_sock_queue *queue)
0e87506f ACM	231	{
	232	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;
	233	}
	234
463c84b9	235	static inline int reqsk_queue_len_young(const struct request_sock_queue *queue)
0e87506f ACM	236	{
	237	return queue->listen_opt->qlen_young;
	238	}
	239
463c84b9	240	static inline int reqsk_queue_is_full(const struct request_sock_queue *queue)
0e87506f ACM	241	{
	242	return queue->listen_opt->qlen >> queue->listen_opt->max_qlen_log;
	243	}
	244
	245	static inline void reqsk_queue_hash_req(struct request_sock_queue *queue,
	246	u32 hash, struct request_sock *req,
8129765a	247	unsigned long timeout)
0e87506f	248	{
2ad69c55	249	struct listen_sock *lopt = queue->listen_opt;
0e87506f ACM	250
	251	req->expires = jiffies + timeout;
	252	req->retrans = 0;
	253	req->sk = NULL;
	254	req->dl_next = lopt->syn_table[hash];
	255
	256	write_lock(&queue->syn_wait_lock);
	257	lopt->syn_table[hash] = req;
	258	write_unlock(&queue->syn_wait_lock);
	259	}
	260
2e6599cb	261	#endif /* _REQUEST_SOCK_H */