/*
   * 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/sock_diag.h>

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

  			struct netlink_callback *cb,
  			const struct inet_diag_req_v2 *req,

  			struct nlattr *bc, bool net_admin)

  {
  	if (!inet_diag_bc_sk(bc, sk))
  		return 0;

  	return inet_sk_diag_fill(sk, NULL, skb, req,

  			sk_user_ns(NETLINK_CB(cb->skb).sk),

  			NETLINK_CB(cb->skb).portid,

  			cb->nlh->nlmsg_seq, NLM_F_MULTI, cb->nlh, net_admin);

  }

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

  			const struct nlmsghdr *nlh,
  			const struct inet_diag_req_v2 *req)

  {

  	int err = -EINVAL;

  	struct sock *sk = NULL;

  	struct sk_buff *rep;

  	struct net *net = sock_net(in_skb->sk);

  	rcu_read_lock();

  	if (req->sdiag_family == AF_INET)

  		sk = __udp4_lib_lookup(net,

  				req->id.idiag_src[0], req->id.idiag_sport,
  				req->id.idiag_dst[0], req->id.idiag_dport,

  				req->id.idiag_if, tbl, NULL);

  #if IS_ENABLED(CONFIG_IPV6)

  	else if (req->sdiag_family == AF_INET6)

  		sk = __udp6_lib_lookup(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, NULL);

  #endif

  	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
  		sk = NULL;
  	rcu_read_unlock();

  	err = -ENOENT;

  	if (!sk)

  		goto out_nosk;

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

  	if (err)
  		goto out;
  
  	err = -ENOMEM;

  	rep = nlmsg_new(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,

  			   sk_user_ns(NETLINK_CB(in_skb).sk),

  			   NETLINK_CB(in_skb).portid,

  			   nlh->nlmsg_seq, 0, nlh,
  			   netlink_net_capable(in_skb, CAP_NET_ADMIN));

  	if (err < 0) {
  		WARN_ON(err == -EMSGSIZE);
  		kfree_skb(rep);
  		goto out;
  	}

  	err = netlink_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid,

  			      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,
  		     const struct inet_diag_req_v2 *r, struct nlattr *bc)

  {

  	bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);

  	struct net *net = sock_net(skb->sk);

  	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; s_num = 0, slot++) {

  		struct udp_hslot *hslot = &table->hash[slot];

  		struct sock *sk;

  		num = 0;

  		if (hlist_empty(&hslot->head))

  			continue;
  
  		spin_lock_bh(&hslot->lock);

  		sk_for_each(sk, &hslot->head) {

  			struct inet_sock *inet = inet_sk(sk);

  			if (!net_eq(sock_net(sk), net))
  				continue;

  			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, net_admin) < 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,

  			  const 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,

  			     const struct inet_diag_req_v2 *req)

  {
  	return udp_dump_one(&udp_table, in_skb, nlh, req);
  }

  static void udp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
  		void *info)
  {
  	r->idiag_rqueue = sk_rmem_alloc_get(sk);
  	r->idiag_wqueue = sk_wmem_alloc_get(sk);
  }

  #ifdef CONFIG_INET_DIAG_DESTROY
  static int __udp_diag_destroy(struct sk_buff *in_skb,
  			      const struct inet_diag_req_v2 *req,
  			      struct udp_table *tbl)
  {
  	struct net *net = sock_net(in_skb->sk);
  	struct sock *sk;
  	int err;
  
  	rcu_read_lock();
  
  	if (req->sdiag_family == AF_INET)
  		sk = __udp4_lib_lookup(net,
  				req->id.idiag_dst[0], req->id.idiag_dport,
  				req->id.idiag_src[0], req->id.idiag_sport,
  				req->id.idiag_if, tbl, NULL);
  #if IS_ENABLED(CONFIG_IPV6)
  	else if (req->sdiag_family == AF_INET6) {
  		if (ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_dst) &&
  		    ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_src))
  			sk = __udp4_lib_lookup(net,

  					req->id.idiag_dst[3], req->id.idiag_dport,
  					req->id.idiag_src[3], req->id.idiag_sport,

  					req->id.idiag_if, tbl, NULL);
  
  		else
  			sk = __udp6_lib_lookup(net,
  					(struct in6_addr *)req->id.idiag_dst,
  					req->id.idiag_dport,
  					(struct in6_addr *)req->id.idiag_src,
  					req->id.idiag_sport,
  					req->id.idiag_if, tbl, NULL);
  	}
  #endif
  	else {
  		rcu_read_unlock();
  		return -EINVAL;
  	}
  
  	if (sk && !atomic_inc_not_zero(&sk->sk_refcnt))
  		sk = NULL;
  
  	rcu_read_unlock();
  
  	if (!sk)
  		return -ENOENT;
  
  	if (sock_diag_check_cookie(sk, req->id.idiag_cookie)) {
  		sock_put(sk);
  		return -ENOENT;
  	}
  
  	err = sock_diag_destroy(sk, ECONNABORTED);
  
  	sock_put(sk);
  
  	return err;
  }
  
  static int udp_diag_destroy(struct sk_buff *in_skb,
  			    const struct inet_diag_req_v2 *req)
  {
  	return __udp_diag_destroy(in_skb, req, &udp_table);
  }
  
  static int udplite_diag_destroy(struct sk_buff *in_skb,
  				const struct inet_diag_req_v2 *req)
  {
  	return __udp_diag_destroy(in_skb, req, &udplite_table);
  }
  
  #endif

  static const struct inet_diag_handler udp_diag_handler = {
  	.dump		 = udp_diag_dump,
  	.dump_one	 = udp_diag_dump_one,

  	.idiag_get_info  = udp_diag_get_info,

  	.idiag_type	 = IPPROTO_UDP,

  	.idiag_info_size = 0,

  #ifdef CONFIG_INET_DIAG_DESTROY
  	.destroy	 = udp_diag_destroy,
  #endif

  };
  
  static void udplite_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,

  			      const 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,

  				 const 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_get_info  = udp_diag_get_info,

  	.idiag_type	 = IPPROTO_UDPLITE,

  	.idiag_info_size = 0,

  #ifdef CONFIG_INET_DIAG_DESTROY
  	.destroy	 = udplite_diag_destroy,
  #endif

  };
  
  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 */);