udp.h

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/*
 * 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, <[email protected]>
 *
 *      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 <net/inet_sock.h>
#include <linux/skbuff.h>
#include <net/netns/hash.h>
#include <uapi/linux/udp.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  /* _LINUX_UDP_H */