/*
 * 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 AF_INET socket handler.
 *
 * Version:     @(#)sock.h      1.0.4   05/13/93
 *
 * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *              Corey Minyard <wf-rch!minyard@relay.EU.net>
 *              Florian La Roche <flla@stud.uni-sb.de>
 *
 * Fixes:
 *              Alan Cox        :       Volatiles in skbuff pointers. See
 *                                      skbuff comments. May be overdone,
 *                                      better to prove they can be removed
 *                                      than the reverse.
 *              Alan Cox        :       Added a zapped field for tcp to note
 *                                      a socket is reset and must stay shut up
 *              Alan Cox        :       New fields for options
 *      Pauline Middelink       :       identd support
 *              Alan Cox        :       Eliminate low level recv/recvfrom
 *              David S. Miller :       New socket lookup architecture.
 *              Steve Whitehouse:       Default routines for sock_ops
 *
 *              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 _SOCK_H
#define _SOCK_H

#include <linux/config.h>
#include <linux/timer.h>
#include <linux/cache.h>
#include <linux/in.h>           /* struct sockaddr_in */

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
#include <linux/in6.h>          /* struct sockaddr_in6 */
#include <linux/ipv6.h>         /* dest_cache, inet6_options */
#include <linux/icmpv6.h>
#include <net/if_inet6.h>       /* struct ipv6_mc_socklist */
#endif

#if defined(CONFIG_INET) || defined (CONFIG_INET_MODULE)
#include <linux/icmp.h>
#endif
#include <linux/tcp.h>          /* struct tcphdr */
#if defined(CONFIG_IP_SCTP) || defined (CONFIG_IP_SCTP_MODULE)
#include <net/sctp/structs.h>   /* struct sctp_opt */
#endif

#include <linux/netdevice.h>
#include <linux/skbuff.h>       /* struct sk_buff */
#include <net/protocol.h>               /* struct inet_protocol */
#if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
#include <net/x25.h>
#endif
#if defined(CONFIG_WAN_ROUTER) || defined(CONFIG_WAN_ROUTER_MODULE)
#include <linux/if_wanpipe.h>
#endif

#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
#include <net/ax25.h>
#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
#include <net/netrom.h>
#endif
#if defined(CONFIG_ROSE) || defined(CONFIG_ROSE_MODULE)
#include <net/rose.h>
#endif
#endif

#if defined(CONFIG_PPPOE) || defined(CONFIG_PPPOE_MODULE)
#include <linux/if_pppox.h>
#include <linux/ppp_channel.h>   /* struct ppp_channel */
#endif

#if defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)
#if defined(CONFIG_SPX) || defined(CONFIG_SPX_MODULE)
#include <net/spx.h>
#else
#include <net/ipx.h>
#endif /* CONFIG_SPX */
#endif /* CONFIG_IPX */

#if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)
#include <linux/atalk.h>
#endif

#if defined(CONFIG_DECNET) || defined(CONFIG_DECNET_MODULE)
#include <net/dn.h>
#endif

#if defined(CONFIG_IRDA) || defined(CONFIG_IRDA_MODULE)
#include <net/irda/irda.h>
#endif

#if defined(CONFIG_ATM) || defined(CONFIG_ATM_MODULE)
struct atm_vcc;
#endif

#ifdef CONFIG_FILTER
#include <linux/filter.h>
#endif

#include <asm/atomic.h>
#include <net/dst.h>


/* The AF_UNIX specific socket options */
struct unix_opt {
        struct unix_address     *addr;
        struct dentry *         dentry;
        struct vfsmount *       mnt;
        struct semaphore        readsem;
        struct sock *           other;
        struct sock **          list;
        struct sock *           gc_tree;
        atomic_t                inflight;
        rwlock_t                lock;
        wait_queue_head_t       peer_wait;
};


/* Once the IPX ncpd patches are in these are going into protinfo. */
#if defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)
struct ipx_opt {
        ipx_address             dest_addr;
        ipx_interface           *intrfc;
        unsigned short          port;
#ifdef CONFIG_IPX_INTERN
        unsigned char           node[IPX_NODE_LEN];
#endif
        unsigned short          type;
/* 
 * To handle special ncp connection-handling sockets for mars_nwe,
 * the connection number must be stored in the socket.
 */
        unsigned short          ipx_ncp_conn;
};
#endif

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
struct ipv6_pinfo {
        struct in6_addr         saddr;
        struct in6_addr         rcv_saddr;
        struct in6_addr         daddr;
        struct in6_addr         *daddr_cache;

        __u32                   flow_label;
        __u32                   frag_size;
        int                     hop_limit;
        int                     mcast_hops;
        int                     mcast_oif;

        /* pktoption flags */
        union {
                struct {
                        __u8    srcrt:2,
                                rxinfo:1,
                                rxhlim:1,
                                hopopts:1,
                                dstopts:1,
                                authhdr:1,
                                rxflow:1;
                } bits;
                __u8            all;
        } rxopt;

        /* sockopt flags */
        __u8                    mc_loop:1,
                                recverr:1,
                                sndflow:1,
                                pmtudisc:2,
                                ipv6only:1;

        struct ipv6_mc_socklist *ipv6_mc_list;
        struct ipv6_ac_socklist *ipv6_ac_list;
        struct ipv6_fl_socklist *ipv6_fl_list;
        __u32                   dst_cookie;

        struct ipv6_txoptions   *opt;
        struct sk_buff          *pktoptions;
};

struct raw6_opt {
        __u32                   checksum;       /* perform checksum */
        __u32                   offset;         /* checksum offset  */

        struct icmp6_filter     filter;
};

#define __ipv6_only_sock(sk)    ((sk)->net_pinfo.af_inet6.ipv6only)
#define ipv6_only_sock(sk)      ((sk)->family == PF_INET6 && \
                                 (sk)->net_pinfo.af_inet6.ipv6only)
#else
#define __ipv6_only_sock(sk)    0
#define ipv6_only_sock(sk)      0
#endif /* IPV6 */

#if defined(CONFIG_INET) || defined(CONFIG_INET_MODULE)
struct raw_opt {
        struct icmp_filter      filter;
};
#endif

#if defined(CONFIG_INET) || defined (CONFIG_INET_MODULE)
struct inet_opt
{
        int                     ttl;                    /* TTL setting */
        int                     tos;                    /* TOS */
        unsigned                cmsg_flags;
        struct ip_options       *opt;
        unsigned char           hdrincl;                /* Include headers ? */
        __u8                    mc_ttl;                 /* Multicasting TTL */
        __u8                    mc_loop;                /* Loopback */
        unsigned                recverr : 1,
                                freebind : 1;
        __u16                   id;                     /* ID counter for DF pkts */
        __u8                    pmtudisc;
        int                     mc_index;               /* Multicast device index */
        __u32                   mc_addr;
        struct ip_mc_socklist   *mc_list;               /* Group array */
};
#endif

#if defined(CONFIG_PPPOE) || defined (CONFIG_PPPOE_MODULE)
struct pppoe_opt
{
        struct net_device      *dev;      /* device associated with socket*/
        struct pppoe_addr       pa;       /* what this socket is bound to*/
        struct sockaddr_pppox   relay;    /* what socket data will be
                                             relayed to (PPPoE relaying) */
};

struct pppox_opt
{
        struct ppp_channel      chan;
        struct sock             *sk;
        struct pppox_opt        *next;    /* for hash table */
        union {
                struct pppoe_opt pppoe;
        } proto;
};
#define pppoe_dev       proto.pppoe.dev
#define pppoe_pa        proto.pppoe.pa
#define pppoe_relay     proto.pppoe.relay
#endif

/* This defines a selective acknowledgement block. */
struct tcp_sack_block {
        __u32   start_seq;
        __u32   end_seq;
};

struct tcp_opt {
        int     tcp_header_len; /* Bytes of tcp header to send          */

/*
 *      Header prediction flags
 *      0x5?10 << 16 + snd_wnd in net byte order
 */
        __u32   pred_flags;

/*
 *      RFC793 variables by their proper names. This means you can
 *      read the code and the spec side by side (and laugh ...)
 *      See RFC793 and RFC1122. The RFC writes these in capitals.
 */
        __u32   rcv_nxt;        /* What we want to receive next         */
        __u32   snd_nxt;        /* Next sequence we send                */

        __u32   snd_una;        /* First byte we want an ack for        */
        __u32   snd_sml;        /* Last byte of the most recently transmitted small packet */
        __u32   rcv_tstamp;     /* timestamp of last received ACK (for keepalives) */
        __u32   lsndtime;       /* timestamp of last sent data packet (for restart window) */

        /* Delayed ACK control data */
        struct {
                __u8    pending;        /* ACK is pending */
                __u8    quick;          /* Scheduled number of quick acks       */
                __u8    pingpong;       /* The session is interactive           */
                __u8    blocked;        /* Delayed ACK was blocked by socket lock*/
                __u32   ato;            /* Predicted tick of soft clock         */
                unsigned long timeout;  /* Currently scheduled timeout          */
                __u32   lrcvtime;       /* timestamp of last received data packet*/
                __u16   last_seg_size;  /* Size of last incoming segment        */
                __u16   rcv_mss;        /* MSS used for delayed ACK decisions   */ 
        } ack;

        /* Data for direct copy to user */
        struct {
                struct sk_buff_head     prequeue;
                struct task_struct      *task;
                struct iovec            *iov;
                int                     memory;
                int                     len;
        } ucopy;

        __u32   snd_wl1;        /* Sequence for window update           */
        __u32   snd_wnd;        /* The window we expect to receive      */
        __u32   max_window;     /* Maximal window ever seen from peer   */
        __u32   pmtu_cookie;    /* Last pmtu seen by socket             */
        __u16   mss_cache;      /* Cached effective mss, not including SACKS */
        __u16   mss_clamp;      /* Maximal mss, negotiated at connection setup */
        __u16   ext_header_len; /* Network protocol overhead (IP/IPv6 options) */
        __u8    ca_state;       /* State of fast-retransmit machine     */
        __u8    retransmits;    /* Number of unrecovered RTO timeouts.  */

        __u8    reordering;     /* Packet reordering metric.            */
        __u8    queue_shrunk;   /* Write queue has been shrunk recently.*/
        __u8    defer_accept;   /* User waits for some data after accept() */

/* RTT measurement */
        __u8    backoff;        /* backoff                              */
        __u32   srtt;           /* smothed round trip time << 3         */
        __u32   mdev;           /* medium deviation                     */
        __u32   mdev_max;       /* maximal mdev for the last rtt period */
        __u32   rttvar;         /* smoothed mdev_max                    */
        __u32   rtt_seq;        /* sequence number to update rttvar     */
        __u32   rto;            /* retransmit timeout                   */

        __u32   packets_out;    /* Packets which are "in flight"        */
        __u32   left_out;       /* Packets which leaved network         */
        __u32   retrans_out;    /* Retransmitted packets out            */


/*
 *      Slow start and congestion control (see also Nagle, and Karn & Partridge)
 */
        __u32   snd_ssthresh;   /* Slow start size threshold            */
        __u32   snd_cwnd;       /* Sending congestion window            */
        __u16   snd_cwnd_cnt;   /* Linear increase counter              */
        __u16   snd_cwnd_clamp; /* Do not allow snd_cwnd to grow above this */
        __u32   snd_cwnd_used;
        __u32   snd_cwnd_stamp;

        /* Two commonly used timers in both sender and receiver paths. */
        unsigned long           timeout;
        struct timer_list       retransmit_timer;       /* Resend (no ack)      */
        struct timer_list       delack_timer;           /* Ack delay            */

        struct sk_buff_head     out_of_order_queue; /* Out of order segments go here */

        struct tcp_func         *af_specific;   /* Operations which are AF_INET{4,6} specific   */
        struct sk_buff          *send_head;     /* Front of stuff to transmit                   */
        struct page             *sndmsg_page;   /* Cached page for sendmsg                      */
        u32                     sndmsg_off;     /* Cached offset for sendmsg                    */

        __u32   rcv_wnd;        /* Current receiver window              */
        __u32   rcv_wup;        /* rcv_nxt on last window update sent   */
        __u32   write_seq;      /* Tail(+1) of data held in tcp send buffer */
        __u32   pushed_seq;     /* Last pushed seq, required to talk to windows */
        __u32   copied_seq;     /* Head of yet unread data              */
/*
 *      Options received (usually on last packet, some only on SYN packets).
 */
        char    tstamp_ok,      /* TIMESTAMP seen on SYN packet         */
                wscale_ok,      /* Wscale seen on SYN packet            */
                sack_ok;        /* SACK seen on SYN packet              */
        char    saw_tstamp;     /* Saw TIMESTAMP on last packet         */
        __u8    snd_wscale;     /* Window scaling received from sender  */
        __u8    rcv_wscale;     /* Window scaling to send to receiver   */
        __u8    nonagle;        /* Disable Nagle algorithm?             */
        __u8    keepalive_probes; /* num of allowed keep alive probes   */

/*      PAWS/RTTM data  */
        __u32   rcv_tsval;      /* Time stamp value                     */
        __u32   rcv_tsecr;      /* Time stamp echo reply                */
        __u32   ts_recent;      /* Time stamp to echo next              */
        long    ts_recent_stamp;/* Time we stored ts_recent (for aging) */

/*      SACKs data      */
        __u16   user_mss;       /* mss requested by user in ioctl */
        __u8    dsack;          /* D-SACK is scheduled                  */
        __u8    eff_sacks;      /* Size of SACK array to send with next packet */
        struct tcp_sack_block duplicate_sack[1]; /* D-SACK block */
        struct tcp_sack_block selective_acks[4]; /* The SACKS themselves*/

        __u32   window_clamp;   /* Maximal window to advertise          */
        __u32   rcv_ssthresh;   /* Current window clamp                 */
        __u8    probes_out;     /* unanswered 0 window probes           */
        __u8    num_sacks;      /* Number of SACK blocks                */
        __u16   advmss;         /* Advertised MSS                       */

        __u8    syn_retries;    /* num of allowed syn retries */
        __u8    ecn_flags;      /* ECN status bits.                     */
        __u16   prior_ssthresh; /* ssthresh saved at recovery start     */
        __u32   lost_out;       /* Lost packets                         */
        __u32   sacked_out;     /* SACK'd packets                       */
        __u32   fackets_out;    /* FACK'd packets                       */
        __u32   high_seq;       /* snd_nxt at onset of congestion       */

        __u32   retrans_stamp;  /* Timestamp of the last retransmit,
                                 * also used in SYN-SENT to remember stamp of
                                 * the first SYN. */
        __u32   undo_marker;    /* tracking retrans started here. */
        int     undo_retrans;   /* number of undoable retransmissions. */
        __u32   urg_seq;        /* Seq of received urgent pointer */
        __u16   urg_data;       /* Saved octet of OOB data and control flags */
        __u8    pending;        /* Scheduled timer event        */
        __u8    urg_mode;       /* In urgent mode               */
        __u32   snd_up;         /* Urgent pointer               */

        /* The syn_wait_lock is necessary only to avoid tcp_get_info having
         * to grab the main lock sock while browsing the listening hash
         * (otherwise it's deadlock prone).
         * This lock is acquired in read mode only from tcp_get_info() and
         * it's acquired in write mode _only_ from code that is actively
         * changing the syn_wait_queue. All readers that are holding
         * the master sock lock don't need to grab this lock in read mode
         * too as the syn_wait_queue writes are always protected from
         * the main sock lock.
         */
        rwlock_t                syn_wait_lock;
        struct tcp_listen_opt   *listen_opt;

        /* FIFO of established children */
        struct open_request     *accept_queue;
        struct open_request     *accept_queue_tail;

        int                     write_pending;  /* A write to socket waits to start. */

        unsigned int            keepalive_time;   /* time before keep alive takes place */
        unsigned int            keepalive_intvl;  /* time interval between keep alive probes */
        int                     linger2;

        int                     frto_counter; /* Number of new acks after RTO */
        __u32                   frto_highmark; /* snd_nxt when RTO occurred */

        unsigned long last_synq_overflow; 

/* Receiver side RTT estimation */
        struct {
                __u32   rtt;
                __u32   seq;
                __u32   time;
        } rcv_rtt_est;

/* Receiver queue space */
        struct {
                int     space;
                __u32   seq;
                __u32   time;
        } rcvq_space;

/* TCP Westwood structure */
        struct {
                __u32    bw_ns_est;        /* first bandwidth estimation..not too smoothed 8) */
                __u32    bw_est;           /* bandwidth estimate */
                __u32    rtt_win_sx;       /* here starts a new evaluation... */
                __u32    bk;
                __u32    snd_una;          /* used for evaluating the number of acked bytes */
                __u32    cumul_ack;
                __u32    accounted;
                __u32    rtt;
                __u32    rtt_min;          /* minimum observed RTT */
        } westwood;

/* Vegas variables */
        struct {
                __u32   beg_snd_nxt;    /* right edge during last RTT */
                __u32   beg_snd_una;    /* left edge  during last RTT */
                __u32   beg_snd_cwnd;   /* saves the size of the cwnd */
                __u8    do_vegas;       /* do vegas for this connection */
                __u8    doing_vegas_now;/* if true, do vegas for this RTT */
                __u16   cntRTT;         /* # of RTTs measured within last RTT */
                __u32   minRTT;         /* min of RTTs measured within last RTT (in usec) */
                __u32   baseRTT;        /* the min of all Vegas RTT measurements seen (in usec) */
        } vegas;

        /* BI TCP Parameters */
        struct {
                __u32   cnt;            /* increase cwnd by 1 after this number of ACKs */
                __u32   last_max_cwnd;  /* last maximium snd_cwnd */
                __u32   last_cwnd;      /* the last snd_cwnd */
                __u32   last_stamp;     /* time when updated last_cwnd */
        } bictcp;
};

        
/*
 * This structure really needs to be cleaned up.
 * Most of it is for TCP, and not used by any of
 * the other protocols.
 */

/*
 * The idea is to start moving to a newer struct gradualy
 * 
 * IMHO the newer struct should have the following format:
 * 
 *      struct sock {
 *              sockmem [mem, proto, callbacks]
 *
 *              union or struct {
 *                      ax25;
 *              } ll_pinfo;
 *      
 *              union {
 *                      ipv4;
 *                      ipv6;
 *                      ipx;
 *                      netrom;
 *                      rose;
 *                      x25;
 *              } net_pinfo;
 *
 *              union {
 *                      tcp;
 *                      udp;
 *                      spx;
 *                      netrom;
 *              } tp_pinfo;
 *
 *      }
 *
 * The idea failed because IPv6 transition asssumes dual IP/IPv6 sockets.
 * So, net_pinfo is IPv6 are really, and protinfo unifies all another
 * private areas.
 */

/* Define this to get the sk->debug debugging facility. */
#define SOCK_DEBUGGING
#ifdef SOCK_DEBUGGING
#define SOCK_DEBUG(sk, msg...) do { if((sk) && ((sk)->debug)) printk(KERN_DEBUG msg); } while (0)
#else
#define SOCK_DEBUG(sk, msg...) do { } while (0)
#endif

/* This is the per-socket lock.  The spinlock provides a synchronization
 * between user contexts and software interrupt processing, whereas the
 * mini-semaphore synchronizes multiple users amongst themselves.
 */
typedef struct {
        spinlock_t              slock;
        unsigned int            users;
        wait_queue_head_t       wq;
} socket_lock_t;

#define sock_lock_init(__sk) \
do {    spin_lock_init(&((__sk)->lock.slock)); \
        (__sk)->lock.users = 0; \
        init_waitqueue_head(&((__sk)->lock.wq)); \
} while(0)

struct sock {
        /* Socket demultiplex comparisons on incoming packets. */
        __u32                   daddr;          /* Foreign IPv4 addr                    */
        __u32                   rcv_saddr;      /* Bound local IPv4 addr                */
        __u16                   dport;          /* Destination port                     */
        unsigned short          num;            /* Local port                           */
        int                     bound_dev_if;   /* Bound device index if != 0           */

        /* Main hash linkage for various protocol lookup tables. */
        struct sock             *next;
        struct sock             **pprev;
        struct sock             *bind_next;
        struct sock             **bind_pprev;

        volatile unsigned char  state,          /* Connection state                     */
                                zapped;         /* In ax25 & ipx means not linked       */
        __u16                   sport;          /* Source port                          */

        unsigned short          family;         /* Address family                       */
        unsigned char           reuse;          /* SO_REUSEADDR setting                 */
        unsigned char           shutdown;
        atomic_t                refcnt;         /* Reference count                      */

        socket_lock_t           lock;           /* Synchronizer...                      */
        int                     rcvbuf;         /* Size of receive buffer in bytes      */

        wait_queue_head_t       *sleep;         /* Sock wait queue                      */
        struct dst_entry        *dst_cache;     /* Destination cache                    */
        rwlock_t                dst_lock;
        atomic_t                rmem_alloc;     /* Receive queue bytes committed        */
        struct sk_buff_head     receive_queue;  /* Incoming packets                     */
        atomic_t                wmem_alloc;     /* Transmit queue bytes committed       */
        struct sk_buff_head     write_queue;    /* Packet sending queue                 */
        atomic_t                omem_alloc;     /* "o" is "option" or "other" */
        int                     wmem_queued;    /* Persistent queue size */
        int                     forward_alloc;  /* Space allocated forward. */
        __u32                   saddr;          /* Sending source                       */
        unsigned int            allocation;     /* Allocation mode                      */
        int                     sndbuf;         /* Size of send buffer in bytes         */
        struct sock             *prev;

        /* Not all are volatile, but some are, so we might as well say they all are.
         * XXX Make this a flag word -DaveM
         */
        volatile char           dead,
                                done,
                                urginline,
                                keepopen,
                                linger,
                                destroy,
                                no_check,
                                broadcast,
                                bsdism;
        unsigned char           debug;
        unsigned char           rcvtstamp;
        unsigned char           use_write_queue;
        unsigned char           userlocks;
        /* Hole of 3 bytes. Try to pack. */
        int                     route_caps;
        int                     proc;
        unsigned long           lingertime;

        int                     hashent;
        struct sock             *pair;

        /* The backlog queue is special, it is always used with
         * the per-socket spinlock held and requires low latency
         * access.  Therefore we special case it's implementation.
         */
        struct {
                struct sk_buff *head;
                struct sk_buff *tail;
        } backlog;

        rwlock_t                callback_lock;

        /* Error queue, rarely used. */
        struct sk_buff_head     error_queue;

        struct proto            *prot;

#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
        union {
                struct ipv6_pinfo       af_inet6;
        } net_pinfo;
#endif

        union {
                struct tcp_opt          af_tcp;
#if defined(CONFIG_IP_SCTP) || defined (CONFIG_IP_SCTP_MODULE)
                struct sctp_opt         af_sctp;
#endif
#if defined(CONFIG_INET) || defined (CONFIG_INET_MODULE)
                struct raw_opt          tp_raw4;
#endif
#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
                struct raw6_opt         tp_raw;
#endif /* CONFIG_IPV6 */
#if defined(CONFIG_SPX) || defined (CONFIG_SPX_MODULE)
                struct spx_opt          af_spx;
#endif /* CONFIG_SPX */

        } tp_pinfo;

        int                     err, err_soft;  /* Soft holds errors that don't
                                                   cause failure but are the cause
                                                   of a persistent failure not just
                                                   'timed out' */
        unsigned short          ack_backlog;
        unsigned short          max_ack_backlog;
        __u32                   priority;
        unsigned short          type;
        unsigned char           localroute;     /* Route locally only */
        unsigned char           protocol;
        struct ucred            peercred;
        int                     rcvlowat;
        long                    rcvtimeo;
        long                    sndtimeo;

#ifdef CONFIG_FILTER
        /* Socket Filtering Instructions */
        struct sk_filter        *filter;
#endif /* CONFIG_FILTER */

        /* This is where all the private (optional) areas that don't
         * overlap will eventually live. 
         */
        union {
                void *destruct_hook;
                struct unix_opt af_unix;
#if defined(CONFIG_INET) || defined (CONFIG_INET_MODULE)
                struct inet_opt af_inet;
#endif
#if defined(CONFIG_ATALK) || defined(CONFIG_ATALK_MODULE)
                struct atalk_sock       af_at;
#endif
#if defined(CONFIG_IPX) || defined(CONFIG_IPX_MODULE)
                struct ipx_opt          af_ipx;
#endif
#if defined (CONFIG_DECNET) || defined(CONFIG_DECNET_MODULE)
                struct dn_scp           dn;
#endif
#if defined (CONFIG_PACKET) || defined(CONFIG_PACKET_MODULE)
                struct packet_opt       *af_packet;
#endif
#if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
                x25_cb                  *x25;
#endif
#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
                ax25_cb                 *ax25;
#endif
#if defined(CONFIG_NETROM) || defined(CONFIG_NETROM_MODULE)
                nr_cb                   *nr;
#endif
#if defined(CONFIG_ROSE) || defined(CONFIG_ROSE_MODULE)
                rose_cb                 *rose;
#endif
#if defined(CONFIG_PPPOE) || defined(CONFIG_PPPOE_MODULE)
                struct pppox_opt        *pppox;
#endif
                struct netlink_opt      *af_netlink;
#if defined(CONFIG_ECONET) || defined(CONFIG_ECONET_MODULE)
                struct econet_opt       *af_econet;
#endif
#if defined(CONFIG_ATM) || defined(CONFIG_ATM_MODULE)
                struct atm_vcc          *af_atm;
#endif
#if defined(CONFIG_IRDA) || defined(CONFIG_IRDA_MODULE)
                struct irda_sock        *irda;
#endif
#if defined(CONFIG_WAN_ROUTER) || defined(CONFIG_WAN_ROUTER_MODULE)
               struct wanpipe_opt      *af_wanpipe;
#endif
        } protinfo;             


        /* This part is used for the timeout functions. */
        struct timer_list       timer;          /* This is the sock cleanup timer. */
        struct timeval          stamp;

        /* Identd and reporting IO signals */
        struct socket           *socket;

        /* RPC layer private data */
        void                    *user_data;
  
        /* Callbacks */
        void                    (*state_change)(struct sock *sk);
        void                    (*data_ready)(struct sock *sk,int bytes);
        void                    (*write_space)(struct sock *sk);
        void                    (*error_report)(struct sock *sk);

        int                     (*backlog_rcv) (struct sock *sk,
                                                struct sk_buff *skb);  
        void                    (*destruct)(struct sock *sk);
};

/* The per-socket spinlock must be held here. */
#define sk_add_backlog(__sk, __skb)                     \
do {    if((__sk)->backlog.tail == NULL) {              \
                (__sk)->backlog.head =                  \
                     (__sk)->backlog.tail = (__skb);    \
        } else {                                        \
                ((__sk)->backlog.tail)->next = (__skb); \
                (__sk)->backlog.tail = (__skb);         \
        }                                               \
        (__skb)->next = NULL;                           \
} while(0)

/* IP protocol blocks we attach to sockets.
 * socket layer -> transport layer interface
 * transport -> network interface is defined by struct inet_proto
 */
struct proto {
        void                    (*close)(struct sock *sk, 
                                        long timeout);
        int                     (*connect)(struct sock *sk,
                                        struct sockaddr *uaddr, 
                                        int addr_len);
        int                     (*disconnect)(struct sock *sk, int flags);

        struct sock *           (*accept) (struct sock *sk, int flags, int *err);

        int                     (*ioctl)(struct sock *sk, int cmd,
                                         unsigned long arg);
        int                     (*init)(struct sock *sk);
        int                     (*destroy)(struct sock *sk);
        void                    (*shutdown)(struct sock *sk, int how);
        int                     (*setsockopt)(struct sock *sk, int level, 
                                        int optname, char *optval, int optlen);
        int                     (*getsockopt)(struct sock *sk, int level, 
                                        int optname, char *optval, 
                                        int *option);    
        int                     (*sendmsg)(struct sock *sk, struct msghdr *msg,
                                           int len);
        int                     (*recvmsg)(struct sock *sk, struct msghdr *msg,
                                        int len, int noblock, int flags, 
                                        int *addr_len);
        int                     (*bind)(struct sock *sk, 
                                        struct sockaddr *uaddr, int addr_len);

        int                     (*backlog_rcv) (struct sock *sk, 
                                                struct sk_buff *skb);

        /* Keeping track of sk's, looking them up, and port selection methods. */
        void                    (*hash)(struct sock *sk);
        void                    (*unhash)(struct sock *sk);
        int                     (*get_port)(struct sock *sk, unsigned short snum);

        char                    name[32];

        struct {
                int inuse;
                u8  __pad[SMP_CACHE_BYTES - sizeof(int)];
        } stats[NR_CPUS];
};

/* Called with local bh disabled */
static __inline__ void sock_prot_inc_use(struct proto *prot)
{
        prot->stats[smp_processor_id()].inuse++;
}

static __inline__ void sock_prot_dec_use(struct proto *prot)
{
        prot->stats[smp_processor_id()].inuse--;
}

/* About 10 seconds */
#define SOCK_DESTROY_TIME (10*HZ)

/* Sockets 0-1023 can't be bound to unless you are superuser */
#define PROT_SOCK       1024

#define SHUTDOWN_MASK   3
#define RCV_SHUTDOWN    1
#define SEND_SHUTDOWN   2

#define SOCK_SNDBUF_LOCK        1
#define SOCK_RCVBUF_LOCK        2
#define SOCK_BINDADDR_LOCK      4
#define SOCK_BINDPORT_LOCK      8


/* Used by processes to "lock" a socket state, so that
 * interrupts and bottom half handlers won't change it
 * from under us. It essentially blocks any incoming
 * packets, so that we won't get any new data or any
 * packets that change the state of the socket.
 *
 * While locked, BH processing will add new packets to
 * the backlog queue.  This queue is processed by the
 * owner of the socket lock right before it is released.
 *
 * Since ~2.3.5 it is also exclusive sleep lock serializing
 * accesses from user process context.
 */
extern void __lock_sock(struct sock *sk);
extern void __release_sock(struct sock *sk);
#define lock_sock(__sk) \
do {    spin_lock_bh(&((__sk)->lock.slock)); \
        if ((__sk)->lock.users != 0) \
                __lock_sock(__sk); \
        (__sk)->lock.users = 1; \
        spin_unlock_bh(&((__sk)->lock.slock)); \
} while(0)

#define release_sock(__sk) \
do {    spin_lock_bh(&((__sk)->lock.slock)); \
        if ((__sk)->backlog.tail != NULL) \
                __release_sock(__sk); \
        (__sk)->lock.users = 0; \
        if (waitqueue_active(&((__sk)->lock.wq))) wake_up(&((__sk)->lock.wq)); \
        spin_unlock_bh(&((__sk)->lock.slock)); \
} while(0)

/* BH context may only use the following locking interface. */
#define bh_lock_sock(__sk)      spin_lock(&((__sk)->lock.slock))
#define bh_unlock_sock(__sk)    spin_unlock(&((__sk)->lock.slock))

extern struct sock *            sk_alloc(int family, int priority, int zero_it);
extern void                     sk_free(struct sock *sk);

extern struct sk_buff           *sock_wmalloc(struct sock *sk,
                                              unsigned long size, int force,
                                              int priority);
extern struct sk_buff           *sock_rmalloc(struct sock *sk,
                                              unsigned long size, int force,
                                              int priority);
extern void                     sock_wfree(struct sk_buff *skb);
extern void                     sock_rfree(struct sk_buff *skb);

extern int                      sock_setsockopt(struct socket *sock, int level,
                                                int op, char *optval,
                                                int optlen);

extern int                      sock_getsockopt(struct socket *sock, int level,
                                                int op, char *optval, 
                                                int *optlen);
extern struct sk_buff           *sock_alloc_send_skb(struct sock *sk,
                                                     unsigned long size,
                                                     int noblock,
                                                     int *errcode);
extern struct sk_buff           *sock_alloc_send_pskb(struct sock *sk,
                                                      unsigned long header_len,
                                                      unsigned long data_len,
                                                      int noblock,
                                                      int *errcode);
extern void *sock_kmalloc(struct sock *sk, int size, int priority);
extern void sock_kfree_s(struct sock *sk, void *mem, int size);

/*
 * Functions to fill in entries in struct proto_ops when a protocol
 * does not implement a particular function.
 */
extern int                      sock_no_release(struct socket *);
extern int                      sock_no_bind(struct socket *, 
                                             struct sockaddr *, int);
extern int                      sock_no_connect(struct socket *,
                                                struct sockaddr *, int, int);
extern int                      sock_no_socketpair(struct socket *,
                                                   struct socket *);
extern int                      sock_no_accept(struct socket *,
                                               struct socket *, int);
extern int                      sock_no_getname(struct socket *,
                                                struct sockaddr *, int *, int);
extern unsigned int             sock_no_poll(struct file *, struct socket *,
                                             struct poll_table_struct *);
extern int                      sock_no_ioctl(struct socket *, unsigned int,
                                              unsigned long);
extern int                      sock_no_listen(struct socket *, int);
extern int                      sock_no_shutdown(struct socket *, int);
extern int                      sock_no_getsockopt(struct socket *, int , int,
                                                   char *, int *);
extern int                      sock_no_setsockopt(struct socket *, int, int,
                                                   char *, int);
extern int                      sock_no_fcntl(struct socket *, 
                                              unsigned int, unsigned long);
extern int                      sock_no_sendmsg(struct socket *,
                                                struct msghdr *, int,
                                                struct scm_cookie *);
extern int                      sock_no_recvmsg(struct socket *,
                                                struct msghdr *, int, int,
                                                struct scm_cookie *);
extern int                      sock_no_mmap(struct file *file,
                                             struct socket *sock,
                                             struct vm_area_struct *vma);
extern ssize_t                  sock_no_sendpage(struct socket *sock,
                                                struct page *page,
                                                int offset, size_t size, 
                                                int flags);

/*
 *      Default socket callbacks and setup code
 */
 
extern void sock_def_destruct(struct sock *);

/* Initialise core socket variables */
extern void sock_init_data(struct socket *sock, struct sock *sk);

extern void sklist_remove_socket(struct sock **list, struct sock *sk);
extern void sklist_insert_socket(struct sock **list, struct sock *sk);
extern void sklist_destroy_socket(struct sock **list, struct sock *sk);

#ifdef CONFIG_FILTER

/**
 *      sk_filter - run a packet through a socket filter
 *      @sk: sock associated with &sk_buff
 *      @skb: buffer to filter
 *      @needlock: set to 1 if the sock is not locked by caller.
 *
 * Run the filter code and then cut skb->data to correct size returned by
 * sk_run_filter. If pkt_len is 0 we toss packet. If skb->len is smaller
 * than pkt_len we keep whole skb->data. This is the socket level
 * wrapper to sk_run_filter. It returns 0 if the packet should
 * be accepted or -EPERM if the packet should be tossed.
 */

static inline int sk_filter(struct sock *sk, struct sk_buff *skb, int needlock)
{
        int err = 0;

        if (sk->filter) {
                struct sk_filter *filter;
                
                if (needlock)
                        bh_lock_sock(sk);
                
                filter = sk->filter;
                if (filter) {
                        int pkt_len = sk_run_filter(skb, filter->insns,
                                                    filter->len);
                        if (!pkt_len)
                                err = -EPERM;
                        else
                                skb_trim(skb, pkt_len);
                }

                if (needlock)
                        bh_unlock_sock(sk);
        }
        return err;
}

/**
 *      sk_filter_release: Release a socket filter
 *      @sk: socket
 *      @fp: filter to remove
 *

 *      Remove a filter from a socket and release its resources.
 */
 
static inline void sk_filter_release(struct sock *sk, struct sk_filter *fp)
{
        unsigned int size = sk_filter_len(fp);

        atomic_sub(size, &sk->omem_alloc);

        if (atomic_dec_and_test(&fp->refcnt))
                kfree(fp);
}

static inline void sk_filter_charge(struct sock *sk, struct sk_filter *fp)
{
        atomic_inc(&fp->refcnt);
        atomic_add(sk_filter_len(fp), &sk->omem_alloc);
}

#else

static inline int sk_filter(struct sock *sk, struct sk_buff *skb, int needlock)
{
        return 0;
}

#endif /* CONFIG_FILTER */

/*
 * Socket reference counting postulates.
 *
 * * Each user of socket SHOULD hold a reference count.
 * * Each access point to socket (an hash table bucket, reference from a list,
 *   running timer, skb in flight MUST hold a reference count.
 * * When reference count hits 0, it means it will never increase back.
 * * When reference count hits 0, it means that no references from
 *   outside exist to this socket and current process on current CPU
 *   is last user and may/should destroy this socket.
 * * sk_free is called from any context: process, BH, IRQ. When
 *   it is called, socket has no references from outside -> sk_free
 *   may release descendant resources allocated by the socket, but
 *   to the time when it is called, socket is NOT referenced by any
 *   hash tables, lists etc.
 * * Packets, delivered from outside (from network or from another process)
 *   and enqueued on receive/error queues SHOULD NOT grab reference count,
 *   when they sit in queue. Otherwise, packets will leak to hole, when
 *   socket is looked up by one cpu and unhasing is made by another CPU.
 *   It is true for udp/raw, netlink (leak to receive and error queues), tcp
 *   (leak to backlog). Packet socket does all the processing inside
 *   BR_NETPROTO_LOCK, so that it has not this race condition. UNIX sockets
 *   use separate SMP lock, so that they are prone too.
 */

/* Grab socket reference count. This operation is valid only
   when sk is ALREADY grabbed f.e. it is found in hash table
   or a list and the lookup is made under lock preventing hash table
   modifications.
 */

static inline void sock_hold(struct sock *sk)
{
        atomic_inc(&sk->refcnt);
}

/* Ungrab socket in the context, which assumes that socket refcnt
   cannot hit zero, f.e. it is true in context of any socketcall.
 */
static inline void __sock_put(struct sock *sk)
{
        atomic_dec(&sk->refcnt);
}

/* Ungrab socket and destroy it, if it was the last reference. */
static inline void sock_put(struct sock *sk)
{
        if (atomic_dec_and_test(&sk->refcnt))
                sk_free(sk);
}

/* Detach socket from process context.
 * Announce socket dead, detach it from wait queue and inode.
 * Note that parent inode held reference count on this struct sock,
 * we do not release it in this function, because protocol
 * probably wants some additional cleanups or even continuing
 * to work with this socket (TCP).
 */
static inline void sock_orphan(struct sock *sk)
{
        write_lock_bh(&sk->callback_lock);
        sk->dead = 1;
        sk->socket = NULL;
        sk->sleep = NULL;
        write_unlock_bh(&sk->callback_lock);
}

static inline void sock_graft(struct sock *sk, struct socket *parent)
{
        write_lock_bh(&sk->callback_lock);
        sk->sleep = &parent->wait;
        parent->sk = sk;
        sk->socket = parent;
        write_unlock_bh(&sk->callback_lock);
}

static inline int sock_i_uid(struct sock *sk)
{
        int uid;

        read_lock(&sk->callback_lock);
        uid = sk->socket ? sk->socket->inode->i_uid : 0;
        read_unlock(&sk->callback_lock);
        return uid;
}

static inline unsigned long sock_i_ino(struct sock *sk)
{
        unsigned long ino;

        read_lock(&sk->callback_lock);
        ino = sk->socket ? sk->socket->inode->i_ino : 0;
        read_unlock(&sk->callback_lock);
        return ino;
}

static inline struct dst_entry *
__sk_dst_get(struct sock *sk)
{
        return sk->dst_cache;
}

static inline struct dst_entry *
sk_dst_get(struct sock *sk)
{
        struct dst_entry *dst;

        read_lock(&sk->dst_lock);
        dst = sk->dst_cache;
        if (dst)
                dst_hold(dst);
        read_unlock(&sk->dst_lock);
        return dst;
}

static inline void
__sk_dst_set(struct sock *sk, struct dst_entry *dst)
{
        struct dst_entry *old_dst;

        old_dst = sk->dst_cache;
        sk->dst_cache = dst;
        dst_release(old_dst);
}

static inline void
sk_dst_set(struct sock *sk, struct dst_entry *dst)
{
        write_lock(&sk->dst_lock);
        __sk_dst_set(sk, dst);
        write_unlock(&sk->dst_lock);
}

static inline void
__sk_dst_reset(struct sock *sk)
{
        struct dst_entry *old_dst;

        old_dst = sk->dst_cache;
        sk->dst_cache = NULL;
        dst_release(old_dst);
}

static inline void
sk_dst_reset(struct sock *sk)
{
        write_lock(&sk->dst_lock);
        __sk_dst_reset(sk);
        write_unlock(&sk->dst_lock);
}

static inline struct dst_entry *
__sk_dst_check(struct sock *sk, u32 cookie)
{
        struct dst_entry *dst = sk->dst_cache;

        if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
                sk->dst_cache = NULL;
                return NULL;
        }

        return dst;
}

static inline struct dst_entry *
sk_dst_check(struct sock *sk, u32 cookie)
{
        struct dst_entry *dst = sk_dst_get(sk);

        if (dst && dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
                sk_dst_reset(sk);
                return NULL;
        }

        return dst;
}


/*
 *      Queue a received datagram if it will fit. Stream and sequenced
 *      protocols can't normally use this as they need to fit buffers in
 *      and play with them.
 *
 *      Inlined as it's very short and called for pretty much every
 *      packet ever received.
 */

static inline void skb_set_owner_w(struct sk_buff *skb, struct sock *sk)
{
        sock_hold(sk);
        skb->sk = sk;
        skb->destructor = sock_wfree;
        atomic_add(skb->truesize, &sk->wmem_alloc);
}

static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
{
        skb->sk = sk;
        skb->destructor = sock_rfree;
        atomic_add(skb->truesize, &sk->rmem_alloc);
}

static inline int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
        int err = 0;
        int skb_len;

        /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
           number of warnings when compiling with -W --ANK
         */
        if (atomic_read(&sk->rmem_alloc) + skb->truesize >= (unsigned)sk->rcvbuf) {
                err = -ENOMEM;
                goto out;
        }

        /* It would be deadlock, if sock_queue_rcv_skb is used
           with socket lock! We assume that users of this
           function are lock free.
        */
        err = sk_filter(sk, skb, 1);
        if (err)
                goto out;

        skb->dev = NULL;
        skb_set_owner_r(skb, sk);

        /* Cache the SKB length before we tack it onto the receive
         * queue.  Once it is added it no longer belongs to us and
         * may be freed by other threads of control pulling packets
         * from the queue.
         */
        skb_len = skb->len;

        skb_queue_tail(&sk->receive_queue, skb);
        if (!sk->dead)
                sk->data_ready(sk,skb_len);
out:
        return err;
}

static inline int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
{
        /* Cast skb->rcvbuf to unsigned... It's pointless, but reduces
           number of warnings when compiling with -W --ANK
         */
        if (atomic_read(&sk->rmem_alloc) + skb->truesize >= (unsigned)sk->rcvbuf)
                return -ENOMEM;
        skb_set_owner_r(skb, sk);
        skb_queue_tail(&sk->error_queue,skb);
        if (!sk->dead)
                sk->data_ready(sk,skb->len);
        return 0;
}

/*
 *      Recover an error report and clear atomically
 */
 
static inline int sock_error(struct sock *sk)
{
        int err=xchg(&sk->err,0);
        return -err;
}

static inline unsigned long sock_wspace(struct sock *sk)
{
        int amt = 0;

        if (!(sk->shutdown & SEND_SHUTDOWN)) {
                amt = sk->sndbuf - atomic_read(&sk->wmem_alloc);
                if (amt < 0) 
                        amt = 0;
        }
        return amt;
}

static inline void sk_wake_async(struct sock *sk, int how, int band)
{
        if (sk->socket && sk->socket->fasync_list)
                sock_wake_async(sk->socket, how, band);
}

#define SOCK_MIN_SNDBUF 2048
#define SOCK_MIN_RCVBUF 256

/*
 *      Default write policy as shown to user space via poll/select/SIGIO
 */
static inline int sock_writeable(struct sock *sk) 
{
        return atomic_read(&sk->wmem_alloc) < (sk->sndbuf / 2);
}

static inline int gfp_any(void)
{
        return in_softirq() ? GFP_ATOMIC : GFP_KERNEL;
}

static inline long sock_rcvtimeo(struct sock *sk, int noblock)
{
        return noblock ? 0 : sk->rcvtimeo;
}

static inline long sock_sndtimeo(struct sock *sk, int noblock)
{
        return noblock ? 0 : sk->sndtimeo;
}

static inline int sock_rcvlowat(struct sock *sk, int waitall, int len)
{
        return (waitall ? len : min_t(int, sk->rcvlowat, len)) ? : 1;
}

/* Alas, with timeout socket operations are not restartable.
 * Compare this to poll().
 */
static inline int sock_intr_errno(long timeo)
{
        return timeo == MAX_SCHEDULE_TIMEOUT ? -ERESTARTSYS : -EINTR;
}

static __inline__ void
sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
{
        if (sk->rcvtstamp)
                put_cmsg(msg, SOL_SOCKET, SO_TIMESTAMP, sizeof(skb->stamp), &skb->stamp);
        else
                sk->stamp = skb->stamp;
}

/* 
 *      Enable debug/info messages 
 */

#if 0
#define NETDEBUG(x)     do { } while (0)
#else
#define NETDEBUG(x)     do { x; } while (0)
#endif

/*
 * Macros for sleeping on a socket. Use them like this:
 *
 * SOCK_SLEEP_PRE(sk)
 * if (condition)
 *      schedule();
 * SOCK_SLEEP_POST(sk)
 *
 */

#define SOCK_SLEEP_PRE(sk)      { struct task_struct *tsk = current; \
                                DECLARE_WAITQUEUE(wait, tsk); \
                                tsk->state = TASK_INTERRUPTIBLE; \
                                add_wait_queue((sk)->sleep, &wait); \
                                release_sock(sk);

#define SOCK_SLEEP_POST(sk)     tsk->state = TASK_RUNNING; \
                                remove_wait_queue((sk)->sleep, &wait); \
                                lock_sock(sk); \
                                }

extern __u32 sysctl_wmem_max;
extern __u32 sysctl_rmem_max;

#endif  /* _SOCK_H */