MAJOR=13
MINOR=34
DEVNAME=input/mouse2
     闇ﾊヒﾇ榮ｿﾈ      /* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * 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
 */
#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 <linux/refcount.h>

#include <net/sock.h>
#include <net/rstreason.h>

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

struct request_sock_ops {
	int		family;
	unsigned int	obj_size;
	struct kmem_cache	*slab;
	char		*slab_name;
	int		(*rtx_syn_ack)(const struct sock *sk,
				       struct request_sock *req);
	void		(*send_ack)(const struct sock *sk, struct sk_buff *skb,
				    struct request_sock *req);
	void		(*send_reset)(const struct sock *sk,
				      struct sk_buff *skb,
				      enum sk_rst_reason reason);
	void		(*destructor)(struct request_sock *req);
	void		(*syn_ack_timeout)(const struct request_sock *req);
};

int inet_rtx_syn_ack(const struct sock *parent, struct request_sock *req);

struct saved_syn {
	u32 mac_hdrlen;
	u32 network_hdrlen;
	u32 tcp_hdrlen;
	u8 data[];
};

/* struct request_sock - mini sock to represent a connection request
 */
struct request_sock {
	struct sock_common		__req_common;
#define rsk_refcnt			__req_common.skc_refcnt
#define rsk_hash			__req_common.skc_hash
#define rsk_listener			__req_common.skc_listener
#define rsk_window_clamp		__req_common.skc_window_clamp
#define rsk_rcv_wnd			__req_common.skc_rcv_wnd

	struct request_sock		*dl_next;
	u16				mss;
	u8				num_retrans; /* number of retransmits */
	u8				syncookie:1; /* syncookie: encode tcpopts in timestamp */
	u8				num_timeout:7; /* number of timeouts */
	u32				ts_recent;
	struct timer_list		rsk_timer;
	const struct request_sock_ops	*rsk_ops;
	struct sock			*sk;
	struct saved_syn		*saved_syn;
	u32				secid;
	u32				peer_secid;
};

static inline struct request_sock *inet_reqsk(const struct sock *sk)
{
	return (struct request_sock *)sk;
}

static inline struct sock *req_to_sk(struct request_sock *req)
{
	return (struct sock *)req;
}

static inline struct request_sock *
reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
	    bool attach_listener)
{
	struct request_sock *req;

	req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
	if (!req)
		return NULL;
	req->rsk_listener = NULL;
	if (attach_listener) {
		if (unlikely(!refcount_inc_not_zero(&sk_listener->sk_refcnt))) {
			kmem_cache_free(ops->slab, req);
			return NULL;
		}
		req->rsk_listener = sk_listener;
	}
	req->rsk_ops = ops;
	req_to_sk(req)->sk_prot = sk_listener->sk_prot;
	sk_node_init(&req_to_sk(req)->sk_node);
	sk_tx_queue_clear(req_to_sk(req));
	req->saved_syn = NULL;
	req->num_timeout = 0;
	req->num_retrans = 0;
	req->sk = NULL;
	refcount_set(&req->rsk_refcnt, 0);

	return req;
}

static inline void __reqsk_free(struct request_sock *req)
{
	req->rsk_ops->destructor(req);
	if (req->rsk_listener)
		sock_put(req->rsk_listener);
	kfree(req->saved_syn);
	kmem_cache_free(req->rsk_ops->slab, req);
}

static inline void reqsk_free(struct request_sock *req)
{
	WARN_ON_ONCE(refcount_read(&req->rsk_refcnt) != 0);
	__reqsk_free(req);
}

static inline void reqsk_put(struct request_sock *req)
{
	if (refcount_dec_and_test(&req->rsk_refcnt))
		reqsk_free(req);
}

/*
 * For a TCP Fast Open listener -
 *	lock - protects the access to all the reqsk, which is co-owned by
 *		the listener and the child socket.
 *	qlen - pending TFO requests (still in TCP_SYN_RECV).
 *	max_qlen - max TFO reqs allowed before TFO is disabled.
 *
 *	XXX (TFO) - ideally these fields can be made as part of "listen_sock"
 *	structure above. But there is some implementation difficulty due to
 *	listen_sock being part of request_sock_queue hence will be freed when
 *	a listener is stopped. But TFO related fields may continue to be
 *	accessed even after a listener is closed, until i