/*
   * INET		An implementation of the TCP/IP protocol suite for the LINUX
   *		operating system.  INET is implemented using the  BSD Socket
   *		interface as the means of communication with the user level.
   *
   *		Definitions for the UDP protocol.
   *
   * Version:	@(#)udp.h	1.0.2	04/28/93
   *
   * Author:	Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
   *
   *		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 _LINUX_UDP_H
  #define _LINUX_UDP_H
  
  #include <linux/types.h>
  
  struct udphdr {

  	__be16	source;
  	__be16	dest;
  	__be16	len;

  	__sum16	check;

  };
  
  /* UDP socket options */
  #define UDP_CORK	1	/* Never send partially complete segments */
  #define UDP_ENCAP	100	/* Set the socket to accept encapsulated packets */
  
  /* UDP encapsulation types */
  #define UDP_ENCAP_ESPINUDP_NON_IKE	1 /* draft-ietf-ipsec-nat-t-ike-00/01 */
  #define UDP_ENCAP_ESPINUDP	2 /* draft-ietf-ipsec-udp-encaps-06 */

  #define UDP_ENCAP_L2TPINUDP	3 /* rfc2661 */

  
  #ifdef __KERNEL__

  #include <net/inet_sock.h>

  #include <linux/skbuff.h>

  #include <net/netns/hash.h>

  
  static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
  {
  	return (struct udphdr *)skb_transport_header(skb);
  }

  #define UDP_HTABLE_SIZE_MIN		(CONFIG_BASE_SMALL ? 128 : 256)

  static inline int udp_hashfn(struct net *net, unsigned num, unsigned mask)

  {

  	return (num + net_hash_mix(net)) & mask;

  }

  struct udp_sock {
  	/* inet_sock has to be the first member */
  	struct inet_sock inet;

  #define udp_port_hash		inet.sk.__sk_common.skc_u16hashes[0]
  #define udp_portaddr_hash	inet.sk.__sk_common.skc_u16hashes[1]

  #define udp_portaddr_node	inet.sk.__sk_common.skc_portaddr_node

  	int		 pending;	/* Any pending frames ? */
  	unsigned int	 corkflag;	/* Cork is required */
    	__u16		 encap_type;	/* Is this an Encapsulation socket? */
  	/*

  	 * Following member retains the information to create a UDP header

  	 * when the socket is uncorked.
  	 */
  	__u16		 len;		/* total length of pending frames */

  	/*
  	 * Fields specific to UDP-Lite.
  	 */
  	__u16		 pcslen;
  	__u16		 pcrlen;
  /* indicator bits used by pcflag: */
  #define UDPLITE_BIT      0x1  		/* set by udplite proto init function */
  #define UDPLITE_SEND_CC  0x2  		/* set via udplite setsockopt         */
  #define UDPLITE_RECV_CC  0x4		/* set via udplite setsocktopt        */
  	__u8		 pcflag;        /* marks socket as UDP-Lite if > 0    */

  	__u8		 unused[3];
  	/*
  	 * For encapsulation sockets.
  	 */
  	int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);

  };
  
  static inline struct udp_sock *udp_sk(const struct sock *sk)
  {
  	return (struct udp_sock *)sk;
  }

  #define udp_portaddr_for_each_entry(__sk, node, list) \
  	hlist_nulls_for_each_entry(__sk, node, list, __sk_common.skc_portaddr_node)
  
  #define udp_portaddr_for_each_entry_rcu(__sk, node, list) \
  	hlist_nulls_for_each_entry_rcu(__sk, node, list, __sk_common.skc_portaddr_node)

  #define IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)

  
  #endif
  
  #endif	/* _LINUX_UDP_H */