/* * 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;	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 * @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;	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));} 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(struct request_sock_queue *queue){	return queue->listen_opt != NULL ? queue->listen_opt->qlen : 0;} static inline int reqsk_queue_len_young(struct request_sock_queue *queue){	return queue->listen_opt->qlen_young;} static inline int reqsk_queue_is_full(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 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 */