/*
   * udp_diag.c	Module for monitoring UDP transport protocols sockets.
   *
   * Authors:	Pavel Emelyanov, <xemul@parallels.com>
   *
   *	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/udp.h>
  #include <net/udp.h>
  #include <net/udplite.h>
  #include <linux/inet_diag.h>
  #include <linux/sock_diag.h>

  static int sk_diag_dump(struct sock *sk, struct sk_buff *skb,

  		struct netlink_callback *cb, struct inet_diag_req_v2 *req,

  		struct nlattr *bc)
  {
  	if (!inet_diag_bc_sk(bc, sk))
  		return 0;
  
  	return inet_sk_diag_fill(sk, NULL, skb, req, NETLINK_CB(cb->skb).pid,
  			cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh);
  }

  static int udp_dump_one(struct udp_table *tbl, struct sk_buff *in_skb,

  		const struct nlmsghdr *nlh, struct inet_diag_req_v2 *req)

  {

  	int err = -EINVAL;
  	struct sock *sk;
  	struct sk_buff *rep;
  
  	if (req->sdiag_family == AF_INET)
  		sk = __udp4_lib_lookup(&init_net,
  				req->id.idiag_src[0], req->id.idiag_sport,
  				req->id.idiag_dst[0], req->id.idiag_dport,
  				req->id.idiag_if, tbl);

  #if IS_ENABLED(CONFIG_IPV6)

  	else if (req->sdiag_family == AF_INET6)
  		sk = __udp6_lib_lookup(&init_net,
  				(struct in6_addr *)req->id.idiag_src,
  				req->id.idiag_sport,
  				(struct in6_addr *)req->id.idiag_dst,
  				req->id.idiag_dport,
  				req->id.idiag_if, tbl);

  #endif

  	else
  		goto out_nosk;
  
  	err = -ENOENT;
  	if (sk == NULL)
  		goto out_nosk;

  	err = sock_diag_check_cookie(sk, req->id.idiag_cookie);

  	if (err)
  		goto out;
  
  	err = -ENOMEM;
  	rep = alloc_skb(NLMSG_SPACE((sizeof(struct inet_diag_msg) +
  				     sizeof(struct inet_diag_meminfo) +
  				     64)), GFP_KERNEL);
  	if (!rep)
  		goto out;
  
  	err = inet_sk_diag_fill(sk, NULL, rep, req,
  			   NETLINK_CB(in_skb).pid,
  			   nlh->nlmsg_seq, 0, nlh);
  	if (err < 0) {
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(rep);
  		goto out;
  	}
  	err = netlink_unicast(sock_diag_nlsk, rep, NETLINK_CB(in_skb).pid,
  			      MSG_DONTWAIT);
  	if (err > 0)
  		err = 0;
  out:
  	if (sk)
  		sock_put(sk);
  out_nosk:
  	return err;

  }
  
  static void udp_dump(struct udp_table *table, struct sk_buff *skb, struct netlink_callback *cb,

  		struct inet_diag_req_v2 *r, struct nlattr *bc)

  {

  	int num, s_num, slot, s_slot;
  
  	s_slot = cb->args[0];
  	num = s_num = cb->args[1];
  
  	for (slot = s_slot; slot <= table->mask; num = s_num = 0, slot++) {
  		struct sock *sk;
  		struct hlist_nulls_node *node;
  		struct udp_hslot *hslot = &table->hash[slot];
  
  		if (hlist_nulls_empty(&hslot->head))
  			continue;
  
  		spin_lock_bh(&hslot->lock);
  		sk_nulls_for_each(sk, node, &hslot->head) {
  			struct inet_sock *inet = inet_sk(sk);
  
  			if (num < s_num)
  				goto next;
  			if (!(r->idiag_states & (1 << sk->sk_state)))
  				goto next;
  			if (r->sdiag_family != AF_UNSPEC &&
  					sk->sk_family != r->sdiag_family)
  				goto next;
  			if (r->id.idiag_sport != inet->inet_sport &&
  			    r->id.idiag_sport)
  				goto next;
  			if (r->id.idiag_dport != inet->inet_dport &&
  			    r->id.idiag_dport)
  				goto next;
  
  			if (sk_diag_dump(sk, skb, cb, r, bc) < 0) {
  				spin_unlock_bh(&hslot->lock);
  				goto done;
  			}
  next:
  			num++;
  		}
  		spin_unlock_bh(&hslot->lock);
  	}
  done:
  	cb->args[0] = slot;
  	cb->args[1] = num;

  }
  
  static void udp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,

  		struct inet_diag_req_v2 *r, struct nlattr *bc)

  {
  	udp_dump(&udp_table, skb, cb, r, bc);
  }
  
  static int udp_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,

  		struct inet_diag_req_v2 *req)

  {
  	return udp_dump_one(&udp_table, in_skb, nlh, req);
  }
  
  static const struct inet_diag_handler udp_diag_handler = {
  	.dump		 = udp_diag_dump,
  	.dump_one	 = udp_diag_dump_one,
  	.idiag_type	 = IPPROTO_UDP,
  };
  
  static void udplite_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,

  		struct inet_diag_req_v2 *r, struct nlattr *bc)

  {
  	udp_dump(&udplite_table, skb, cb, r, bc);
  }
  
  static int udplite_diag_dump_one(struct sk_buff *in_skb, const struct nlmsghdr *nlh,

  		struct inet_diag_req_v2 *req)

  {
  	return udp_dump_one(&udplite_table, in_skb, nlh, req);
  }
  
  static const struct inet_diag_handler udplite_diag_handler = {
  	.dump		 = udplite_diag_dump,
  	.dump_one	 = udplite_diag_dump_one,
  	.idiag_type	 = IPPROTO_UDPLITE,
  };
  
  static int __init udp_diag_init(void)
  {
  	int err;
  
  	err = inet_diag_register(&udp_diag_handler);
  	if (err)
  		goto out;
  	err = inet_diag_register(&udplite_diag_handler);
  	if (err)
  		goto out_lite;
  out:
  	return err;
  out_lite:
  	inet_diag_unregister(&udp_diag_handler);
  	goto out;
  }
  
  static void __exit udp_diag_exit(void)
  {
  	inet_diag_unregister(&udplite_diag_handler);
  	inet_diag_unregister(&udp_diag_handler);
  }
  
  module_init(udp_diag_init);
  module_exit(udp_diag_exit);
  MODULE_LICENSE("GPL");

  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-17 /* AF_INET - IPPROTO_UDP */);
  MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-136 /* AF_INET - IPPROTO_UDPLITE */);