root/include/linux/udp.h

INCLUDED FROM

DEFINITIONS

1. udp_hdr
2. udp_hashfn
3. udp_sk

/*
 * 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         128

static inline int udp_hashfn(struct net *net, const unsigned num)
{
        return (num + net_hash_mix(net)) & (UDP_HTABLE_SIZE - 1);
}

struct udp_sock {
        /* inet_sock has to be the first member */
        struct inet_sock inet;
        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 IS_UDPLITE(__sk) (udp_sk(__sk)->pcflag)

#endif

#endif  /* _LINUX_UDP_H */