/*
   * tcp_diag.c	Module for monitoring TCP transport protocols sockets.
   *

   * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
   *
   *	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.
   */

  #include <linux/module.h>
  #include <linux/inet_diag.h>
  
  #include <linux/tcp.h>
  
  #include <net/tcp.h>
  
  static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
  			      void *_info)
  {
  	const struct tcp_sock *tp = tcp_sk(sk);
  	struct tcp_info *info = _info;

  	if (sk->sk_state == TCP_LISTEN) {

  		r->idiag_rqueue = sk->sk_ack_backlog;

  		r->idiag_wqueue = sk->sk_max_ack_backlog;
  	} else {

  		r->idiag_rqueue = max_t(int, tp->rcv_nxt - tp->copied_seq, 0);

  		r->idiag_wqueue = tp->write_seq - tp->snd_una;
  	}

  	if (info != NULL)
  		tcp_get_info(sk, info);
  }

  static void tcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,

  			  struct inet_diag_req_v2 *r, struct nlattr *bc)

  {
  	inet_diag_dump_icsk(&tcp_hashinfo, skb, cb, r, bc);
  }
  
  static int tcp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,

  			     struct inet_diag_req_v2 *req)

  {
  	return inet_diag_dump_one_icsk(&tcp_hashinfo, in_skb, nlh, req);
  }

  static const struct inet_diag_handler tcp_diag_handler = {

  	.dump		 = tcp_diag_dump,
  	.dump_one	 = tcp_diag_dump_one,

  	.idiag_get_info	 = tcp_diag_get_info,

  	.idiag_type	 = IPPROTO_TCP,

  };
  
  static int __init tcp_diag_init(void)
  {
  	return inet_diag_register(&tcp_diag_handler);
  }
  
  static void __exit tcp_diag_exit(void)
  {
  	inet_diag_unregister(&tcp_diag_handler);
  }
  
  module_init(tcp_diag_init);
  module_exit(tcp_diag_exit);
  MODULE_LICENSE("GPL");

  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);