af_inet.c

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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.
 *
 *              PF_INET protocol family socket handler.
 *
 * Version:     $Id: af_inet.c,v 1.136 2001/11/06 22:21:08 davem Exp $
 *
 * Authors:     Ross Biro, <bir7@leland.Stanford.Edu>
 *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *              Florian La Roche, <flla@stud.uni-sb.de>
 *              Alan Cox, <A.Cox@swansea.ac.uk>
 *
 * Changes (see also sock.c)
 *
 *              piggy,
 *              Karl Knutson    :       Socket protocol table
 *              A.N.Kuznetsov   :       Socket death error in accept().
 *              John Richardson :       Fix non blocking error in connect()
 *                                      so sockets that fail to connect
 *                                      don't return -EINPROGRESS.
 *              Alan Cox        :       Asynchronous I/O support
 *              Alan Cox        :       Keep correct socket pointer on sock structures
 *                                      when accept() ed
 *              Alan Cox        :       Semantics of SO_LINGER aren't state moved
 *                                      to close when you look carefully. With
 *                                      this fixed and the accept bug fixed 
 *                                      some RPC stuff seems happier.
 *              Niibe Yutaka    :       4.4BSD style write async I/O
 *              Alan Cox, 
 *              Tony Gale       :       Fixed reuse semantics.
 *              Alan Cox        :       bind() shouldn't abort existing but dead
 *                                      sockets. Stops FTP netin:.. I hope.
 *              Alan Cox        :       bind() works correctly for RAW sockets. Note
 *                                      that FreeBSD at least was broken in this respect
 *                                      so be careful with compatibility tests...
 *              Alan Cox        :       routing cache support
 *              Alan Cox        :       memzero the socket structure for compactness.
 *              Matt Day        :       nonblock connect error handler
 *              Alan Cox        :       Allow large numbers of pending sockets
 *                                      (eg for big web sites), but only if
 *                                      specifically application requested.
 *              Alan Cox        :       New buffering throughout IP. Used dumbly.
 *              Alan Cox        :       New buffering now used smartly.
 *              Alan Cox        :       BSD rather than common sense interpretation of
 *                                      listen.
 *              Germano Caronni :       Assorted small races.
 *              Alan Cox        :       sendmsg/recvmsg basic support.
 *              Alan Cox        :       Only sendmsg/recvmsg now supported.
 *              Alan Cox        :       Locked down bind (see security list).
 *              Alan Cox        :       Loosened bind a little.
 *              Mike McLagan    :       ADD/DEL DLCI Ioctls
 *      Willy Konynenberg       :       Transparent proxying support.
 *              David S. Miller :       New socket lookup architecture.
 *                                      Some other random speedups.
 *              Cyrus Durgin    :       Cleaned up file for kmod hacks.
 *              Andi Kleen      :       Fix inet_stream_connect TCP race.
 *
 *              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/config.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/netfilter_ipv4.h>

#include <asm/uaccess.h>
#include <asm/system.h>

#include <linux/smp_lock.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/brlock.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/arp.h>
#include <net/route.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/raw.h>
#include <net/icmp.h>
#include <net/ipip.h>
#include <net/inet_common.h>
#ifdef CONFIG_IP_MROUTE
#include <linux/mroute.h>
#endif
#include <linux/if_bridge.h>
#ifdef CONFIG_KMOD
#include <linux/kmod.h>
#endif
#ifdef CONFIG_NET_DIVERT
#include <linux/divert.h>
#endif /* CONFIG_NET_DIVERT */
#if defined(CONFIG_NET_RADIO) || defined(CONFIG_NET_PCMCIA_RADIO)
#include <linux/wireless.h>             /* Note : will define WIRELESS_EXT */
#endif  /* CONFIG_NET_RADIO || CONFIG_NET_PCMCIA_RADIO */

struct linux_mib net_statistics[NR_CPUS*2];

#ifdef INET_REFCNT_DEBUG
atomic_t inet_sock_nr;
#endif

extern int raw_get_info(char *, char **, off_t, int);
extern int snmp_get_info(char *, char **, off_t, int);
extern int netstat_get_info(char *, char **, off_t, int);
extern int afinet_get_info(char *, char **, off_t, int);
extern int tcp_get_info(char *, char **, off_t, int);
extern int udp_get_info(char *, char **, off_t, int);
extern void ip_mc_drop_socket(struct sock *sk);

#ifdef CONFIG_DLCI
extern int dlci_ioctl(unsigned int, void*);
#endif

#ifdef CONFIG_DLCI_MODULE
int (*dlci_ioctl_hook)(unsigned int, void *);
#endif

#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
int (*br_ioctl_hook)(unsigned long);
#endif

#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
int (*vlan_ioctl_hook)(unsigned long arg);
#endif

/* The inetsw table contains everything that inet_create needs to
 * build a new socket.
 */
struct list_head inetsw[SOCK_MAX];

/* New destruction routine */

void inet_sock_destruct(struct sock *sk)
{
        __skb_queue_purge(&sk->receive_queue);
        __skb_queue_purge(&sk->error_queue);

        if (sk->type == SOCK_STREAM && sk->state != TCP_CLOSE) {
                printk("Attempt to release TCP socket in state %d %p\n",
                       sk->state,
                       sk);
                return;
        }
        if (!sk->dead) {
                printk("Attempt to release alive inet socket %p\n", sk);
                return;
        }

        BUG_TRAP(atomic_read(&sk->rmem_alloc) == 0);
        BUG_TRAP(atomic_read(&sk->wmem_alloc) == 0);
        BUG_TRAP(sk->wmem_queued == 0);
        BUG_TRAP(sk->forward_alloc == 0);

        if (sk->protinfo.af_inet.opt)
                kfree(sk->protinfo.af_inet.opt);
        dst_release(sk->dst_cache);
#ifdef INET_REFCNT_DEBUG
        atomic_dec(&inet_sock_nr);
        printk(KERN_DEBUG "INET socket %p released, %d are still alive\n", sk, atomic_read(&inet_sock_nr));
#endif
}

void inet_sock_release(struct sock *sk)
{
        if (sk->prot->destroy)
                sk->prot->destroy(sk);

        /* Observation: when inet_sock_release is called, processes have
         * no access to socket. But net still has.
         * Step one, detach it from networking:
         *
         * A. Remove from hash tables.
         */

        sk->prot->unhash(sk);

        /* In this point socket cannot receive new packets,
         * but it is possible that some packets are in flight
         * because some CPU runs receiver and did hash table lookup
         * before we unhashed socket. They will achieve receive queue
         * and will be purged by socket destructor.
         *
         * Also we still have packets pending on receive
         * queue and probably, our own packets waiting in device queues.
         * sock_destroy will drain receive queue, but transmitted
         * packets will delay socket destruction until the last reference
         * will be released.
         */

        sock_orphan(sk);

#ifdef INET_REFCNT_DEBUG
        if (atomic_read(&sk->refcnt) != 1) {
                printk(KERN_DEBUG "Destruction inet %p delayed, c=%d\n", sk, atomic_read(&sk->refcnt));
        }
#endif
        sock_put(sk);
}


/*
 *      The routines beyond this point handle the behaviour of an AF_INET
 *      socket object. Mostly it punts to the subprotocols of IP to do
 *      the work.
 */
 

/*
 *      Set socket options on an inet socket.
 */
 
int inet_setsockopt(struct socket *sock, int level, int optname,
                    char *optval, int optlen)
{
        struct sock *sk=sock->sk;

        return sk->prot->setsockopt(sk,level,optname,optval,optlen);
}

/*
 *      Get a socket option on an AF_INET socket.
 *
 *      FIX: POSIX 1003.1g is very ambiguous here. It states that
 *      asynchronous errors should be reported by getsockopt. We assume
 *      this means if you specify SO_ERROR (otherwise whats the point of it).
 */

int inet_getsockopt(struct socket *sock, int level, int optname,
                    char *optval, int *optlen)
{
        struct sock *sk=sock->sk;

        return sk->prot->getsockopt(sk,level,optname,optval,optlen);
}

/*
 *      Automatically bind an unbound socket.
 */

static int inet_autobind(struct sock *sk)
{
        /* We may need to bind the socket. */
        lock_sock(sk);
        if (sk->num == 0) {
                if (sk->prot->get_port(sk, 0) != 0) {
                        release_sock(sk);
                        return -EAGAIN;
                }
                sk->sport = htons(sk->num);
        }
        release_sock(sk);
        return 0;
}

/*
 *      Move a socket into listening state.
 */
 
int inet_listen(struct socket *sock, int backlog)
{
        struct sock *sk = sock->sk;
        unsigned char old_state;
        int err;

        lock_sock(sk);

        err = -EINVAL;
        if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
                goto out;

        old_state = sk->state;
        if (!((1<<old_state)&(TCPF_CLOSE|TCPF_LISTEN)))
                goto out;

        /* Really, if the socket is already in listen state
         * we can only allow the backlog to be adjusted.
         */
        if (old_state != TCP_LISTEN) {
                err = tcp_listen_start(sk);
                if (err)
                        goto out;
        }
        sk->max_ack_backlog = backlog;
        err = 0;

out:
        release_sock(sk);
        return err;
}

/*
 *      Create an inet socket.
 */

static int inet_create(struct socket *sock, int protocol)
{
        struct sock *sk;
        struct list_head *p;
        struct inet_protosw *answer;

        sock->state = SS_UNCONNECTED;
        sk = sk_alloc(PF_INET, GFP_KERNEL, 1);
        if (sk == NULL) 
                goto do_oom;
  
        /* Look for the requested type/protocol pair. */
        answer = NULL;
        br_read_lock_bh(BR_NETPROTO_LOCK);
        list_for_each(p, &inetsw[sock->type]) {
                answer = list_entry(p, struct inet_protosw, list);

                /* Check the non-wild match. */
                if (protocol == answer->protocol) {
                        if (protocol != IPPROTO_IP)
                                break;
                } else {
                        /* Check for the two wild cases. */
                        if (IPPROTO_IP == protocol) {
                                protocol = answer->protocol;
                                break;
                        }
                        if (IPPROTO_IP == answer->protocol)
                                break;
                }
                answer = NULL;
        }
        br_read_unlock_bh(BR_NETPROTO_LOCK);

        if (!answer)
                goto free_and_badtype;
        if (answer->capability > 0 && !capable(answer->capability))
                goto free_and_badperm;
        if (!protocol)
                goto free_and_noproto;

        sock->ops = answer->ops;
        sk->prot = answer->prot;
        sk->no_check = answer->no_check;
        if (INET_PROTOSW_REUSE & answer->flags)
                sk->reuse = 1;

        if (SOCK_RAW == sock->type) {
                sk->num = protocol;
                if (IPPROTO_RAW == protocol)
                        sk->protinfo.af_inet.hdrincl = 1;
        }

        if (ipv4_config.no_pmtu_disc)
                sk->protinfo.af_inet.pmtudisc = IP_PMTUDISC_DONT;
        else
                sk->protinfo.af_inet.pmtudisc = IP_PMTUDISC_WANT;

        sk->protinfo.af_inet.id = 0;

        sock_init_data(sock,sk);

        sk->destruct = inet_sock_destruct;

        sk->zapped      = 0;
        sk->family      = PF_INET;
        sk->protocol    = protocol;

        sk->backlog_rcv = sk->prot->backlog_rcv;

        sk->protinfo.af_inet.ttl        = sysctl_ip_default_ttl;

        sk->protinfo.af_inet.mc_loop    = 1;
        sk->protinfo.af_inet.mc_ttl     = 1;
        sk->protinfo.af_inet.mc_index   = 0;
        sk->protinfo.af_inet.mc_list    = NULL;

#ifdef INET_REFCNT_DEBUG
        atomic_inc(&inet_sock_nr);
#endif

        if (sk->num) {
                /* It assumes that any protocol which allows
                 * the user to assign a number at socket
                 * creation time automatically
                 * shares.
                 */
                sk->sport = htons(sk->num);

                /* Add to protocol hash chains. */
                sk->prot->hash(sk);
        }

        if (sk->prot->init) {
                int err = sk->prot->init(sk);
                if (err != 0) {
                        inet_sock_release(sk);
                        return err;
                }
        }
        return 0;

free_and_badtype:
        sk_free(sk);
        return -ESOCKTNOSUPPORT;

free_and_badperm:
        sk_free(sk);
        return -EPERM;

free_and_noproto:
        sk_free(sk);
        return -EPROTONOSUPPORT;

do_oom:
        return -ENOBUFS;
}


/*
 *      The peer socket should always be NULL (or else). When we call this
 *      function we are destroying the object and from then on nobody
 *      should refer to it.
 */
 
int inet_release(struct socket *sock)
{
        struct sock *sk = sock->sk;

        if (sk) {
                long timeout;

                /* Applications forget to leave groups before exiting */
                ip_mc_drop_socket(sk);

                /* If linger is set, we don't return until the close
                 * is complete.  Otherwise we return immediately. The
                 * actually closing is done the same either way.
                 *
                 * If the close is due to the process exiting, we never
                 * linger..
                 */
                timeout = 0;
                if (sk->linger && !(current->flags & PF_EXITING))
                        timeout = sk->lingertime;
                sock->sk = NULL;
                sk->prot->close(sk, timeout);
        }
        return(0);
}

/* It is off by default, see below. */
int sysctl_ip_nonlocal_bind;

int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
        struct sockaddr_in *addr=(struct sockaddr_in *)uaddr;
        struct sock *sk=sock->sk;
        unsigned short snum;
        int chk_addr_ret;
        int err;

        /* If the socket has its own bind function then use it. (RAW) */
        if(sk->prot->bind)
                return sk->prot->bind(sk, uaddr, addr_len);

        if (addr_len < sizeof(struct sockaddr_in))
                return -EINVAL;

        chk_addr_ret = inet_addr_type(addr->sin_addr.s_addr);

        /* Not specified by any standard per-se, however it breaks too
         * many applications when removed.  It is unfortunate since
         * allowing applications to make a non-local bind solves
         * several problems with systems using dynamic addressing.
         * (ie. your servers still start up even if your ISDN link
         *  is temporarily down)
         */
        if (sysctl_ip_nonlocal_bind == 0 && 
            sk->protinfo.af_inet.freebind == 0 &&
            addr->sin_addr.s_addr != INADDR_ANY &&
            chk_addr_ret != RTN_LOCAL &&
            chk_addr_ret != RTN_MULTICAST &&
            chk_addr_ret != RTN_BROADCAST)
                return -EADDRNOTAVAIL;

        snum = ntohs(addr->sin_port);
        if (snum && snum < PROT_SOCK && !capable(CAP_NET_BIND_SERVICE))
                return -EACCES;

        /*      We keep a pair of addresses. rcv_saddr is the one
         *      used by hash lookups, and saddr is used for transmit.
         *
         *      In the BSD API these are the same except where it
         *      would be illegal to use them (multicast/broadcast) in
         *      which case the sending device address is used.
         */
        lock_sock(sk);

        /* Check these errors (active socket, double bind). */
        err = -EINVAL;
        if ((sk->state != TCP_CLOSE)                    ||
            (sk->num != 0))
                goto out;

        sk->rcv_saddr = sk->saddr = addr->sin_addr.s_addr;
        if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
                sk->saddr = 0;  /* Use device */

        /* Make sure we are allowed to bind here. */
        if (sk->prot->get_port(sk, snum) != 0) {
                sk->saddr = sk->rcv_saddr = 0;
                err = -EADDRINUSE;
                goto out;
        }

        if (sk->rcv_saddr)
                sk->userlocks |= SOCK_BINDADDR_LOCK;
        if (snum)
                sk->userlocks |= SOCK_BINDPORT_LOCK;
        sk->sport = htons(sk->num);
        sk->daddr = 0;
        sk->dport = 0;
        sk_dst_reset(sk);
        err = 0;
out:
        release_sock(sk);
        return err;
}

int inet_dgram_connect(struct socket *sock, struct sockaddr * uaddr,
                       int addr_len, int flags)
{
        struct sock *sk=sock->sk;

        if (uaddr->sa_family == AF_UNSPEC)
                return sk->prot->disconnect(sk, flags);

        if (sk->num==0 && inet_autobind(sk) != 0)
                return -EAGAIN;
        return sk->prot->connect(sk, (struct sockaddr *)uaddr, addr_len);
}

static long inet_wait_for_connect(struct sock *sk, long timeo)
{
        DECLARE_WAITQUEUE(wait, current);

        __set_current_state(TASK_INTERRUPTIBLE);
        add_wait_queue(sk->sleep, &wait);

        /* Basic assumption: if someone sets sk->err, he _must_
         * change state of the socket from TCP_SYN_*.
         * Connect() does not allow to get error notifications
         * without closing the socket.
         */
        while ((1<<sk->state)&(TCPF_SYN_SENT|TCPF_SYN_RECV)) {
                release_sock(sk);
                timeo = schedule_timeout(timeo);
                lock_sock(sk);
                if (signal_pending(current) || !timeo)
                        break;
                set_current_state(TASK_INTERRUPTIBLE);
        }
        __set_current_state(TASK_RUNNING);
        remove_wait_queue(sk->sleep, &wait);
        return timeo;
}

/*
 *      Connect to a remote host. There is regrettably still a little
 *      TCP 'magic' in here.
 */
 
int inet_stream_connect(struct socket *sock, struct sockaddr * uaddr,
                        int addr_len, int flags)
{
        struct sock *sk=sock->sk;
        int err;
        long timeo;

        lock_sock(sk);

        if (uaddr->sa_family == AF_UNSPEC) {
                err = sk->prot->disconnect(sk, flags);
                sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
                goto out;
        }

        switch (sock->state) {
        default:
                err = -EINVAL;
                goto out;
        case SS_CONNECTED:
                err = -EISCONN;
                goto out;
        case SS_CONNECTING:
                err = -EALREADY;
                /* Fall out of switch with err, set for this state */
                break;
        case SS_UNCONNECTED:
                err = -EISCONN;
                if (sk->state != TCP_CLOSE) 
                        goto out;

                err = sk->prot->connect(sk, uaddr, addr_len);
                if (err < 0)
                        goto out;

                sock->state = SS_CONNECTING;

                /* Just entered SS_CONNECTING state; the only
                 * difference is that return value in non-blocking
                 * case is EINPROGRESS, rather than EALREADY.
                 */
                err = -EINPROGRESS;
                break;
        }

        timeo = sock_sndtimeo(sk, flags&O_NONBLOCK);

        if ((1<<sk->state)&(TCPF_SYN_SENT|TCPF_SYN_RECV)) {
                /* Error code is set above */
                if (!timeo || !inet_wait_for_connect(sk, timeo))
                        goto out;

                err = sock_intr_errno(timeo);
                if (signal_pending(current))
                        goto out;
        }

        /* Connection was closed by RST, timeout, ICMP error
         * or another process disconnected us.
         */
        if (sk->state == TCP_CLOSE)
                goto sock_error;

        /* sk->err may be not zero now, if RECVERR was ordered by user
         * and error was received after socket entered established state.
         * Hence, it is handled normally after connect() return successfully.
         */

        sock->state = SS_CONNECTED;
        err = 0;
out:
        release_sock(sk);
        return err;

sock_error:
        err = sock_error(sk) ? : -ECONNABORTED;
        sock->state = SS_UNCONNECTED;
        if (sk->prot->disconnect(sk, flags))
                sock->state = SS_DISCONNECTING;
        goto out;
}

/*
 *      Accept a pending connection. The TCP layer now gives BSD semantics.
 */

int inet_accept(struct socket *sock, struct socket *newsock, int flags)
{
        struct sock *sk1 = sock->sk;
        struct sock *sk2;
        int err = -EINVAL;

        if((sk2 = sk1->prot->accept(sk1,flags,&err)) == NULL)
                goto do_err;

        lock_sock(sk2);

        BUG_TRAP((1<<sk2->state)&(TCPF_ESTABLISHED|TCPF_CLOSE_WAIT|TCPF_CLOSE));

        sock_graft(sk2, newsock);

        newsock->state = SS_CONNECTED;
        release_sock(sk2);
        return 0;

do_err:
        return err;
}


/*
 *      This does both peername and sockname.
 */
 
int inet_getname(struct socket *sock, struct sockaddr *uaddr,
                 int *uaddr_len, int peer)
{
        struct sock *sk         = sock->sk;
        struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;
  
        sin->sin_family = AF_INET;
        if (peer) {
                if (!sk->dport)
                        return -ENOTCONN;
                if (((1<<sk->state)&(TCPF_CLOSE|TCPF_SYN_SENT)) && peer == 1)
                        return -ENOTCONN;
                sin->sin_port = sk->dport;
                sin->sin_addr.s_addr = sk->daddr;
        } else {
                __u32 addr = sk->rcv_saddr;
                if (!addr)
                        addr = sk->saddr;
                sin->sin_port = sk->sport;
                sin->sin_addr.s_addr = addr;
        }
        *uaddr_len = sizeof(*sin);
        return(0);
}



int inet_recvmsg(struct socket *sock, struct msghdr *msg, int size,
                 int flags, struct scm_cookie *scm)
{
        struct sock *sk = sock->sk;
        int addr_len = 0;
        int err;

        err = sk->prot->recvmsg(sk, msg, size, flags&MSG_DONTWAIT,
                                flags&~MSG_DONTWAIT, &addr_len);
        if (err >= 0)
                msg->msg_namelen = addr_len;
        return err;
}


int inet_sendmsg(struct socket *sock, struct msghdr *msg, int size,
                 struct scm_cookie *scm)
{
        struct sock *sk = sock->sk;

        /* We may need to bind the socket. */
        if (sk->num==0 && inet_autobind(sk) != 0)
                return -EAGAIN;

        return sk->prot->sendmsg(sk, msg, size);
}

int inet_shutdown(struct socket *sock, int how)
{
        struct sock *sk = sock->sk;
        int err = 0;

        /* This should really check to make sure
         * the socket is a TCP socket. (WHY AC...)
         */
        how++; /* maps 0->1 has the advantage of making bit 1 rcvs and
                       1->2 bit 2 snds.
                       2->3 */
        if ((how & ~SHUTDOWN_MASK) || how==0)   /* MAXINT->0 */
                return -EINVAL;

        lock_sock(sk);
        if (sock->state == SS_CONNECTING) {
                if ((1<<sk->state)&(TCPF_SYN_SENT|TCPF_SYN_RECV|TCPF_CLOSE))
                        sock->state = SS_DISCONNECTING;
                else
                        sock->state = SS_CONNECTED;
        }

        switch (sk->state) {
        case TCP_CLOSE:
                err = -ENOTCONN;
                /* Hack to wake up other listeners, who can poll for
                   POLLHUP, even on eg. unconnected UDP sockets -- RR */
        default:
                sk->shutdown |= how;
                if (sk->prot->shutdown)
                        sk->prot->shutdown(sk, how);
                break;

        /* Remaining two branches are temporary solution for missing
         * close() in multithreaded environment. It is _not_ a good idea,
         * but we have no choice until close() is repaired at VFS level.
         */
        case TCP_LISTEN:
                if (!(how & RCV_SHUTDOWN))
                        break;
                /* Fall through */
        case TCP_SYN_SENT:
                err = sk->prot->disconnect(sk, O_NONBLOCK);
                sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
                break;
        }

        /* Wake up anyone sleeping in poll. */
        sk->state_change(sk);
        release_sock(sk);
        return err;
}

/*
 *      ioctl() calls you can issue on an INET socket. Most of these are
 *      device configuration and stuff and very rarely used. Some ioctls
 *      pass on to the socket itself.
 *
 *      NOTE: I like the idea of a module for the config stuff. ie ifconfig
 *      loads the devconfigure module does its configuring and unloads it.
 *      There's a good 20K of config code hanging around the kernel.
 */

int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
        struct sock *sk = sock->sk;
        int err;
        int pid;

        switch(cmd) {
                case FIOSETOWN:
                case SIOCSPGRP:
                        err = get_user(pid, (int *) arg);
                        if (err)
                                return err; 
                        if (current->pid != pid && current->pgrp != -pid && 
                            !capable(CAP_NET_ADMIN))
                                return -EPERM;
                        sk->proc = pid;
                        return(0);
                case FIOGETOWN:
                case SIOCGPGRP:
                        return put_user(sk->proc, (int *)arg);
                case SIOCGSTAMP:
                        if(sk->stamp.tv_sec==0)
                                return -ENOENT;
                        err = copy_to_user((void *)arg,&sk->stamp,sizeof(struct timeval));
                        if (err)
                                err = -EFAULT;
                        return err;
                case SIOCADDRT:
                case SIOCDELRT:
                case SIOCRTMSG:
                        return(ip_rt_ioctl(cmd,(void *) arg));
                case SIOCDARP:
                case SIOCGARP:
                case SIOCSARP:
                        return(arp_ioctl(cmd,(void *) arg));
                case SIOCGIFADDR:
                case SIOCSIFADDR:
                case SIOCGIFBRDADDR:
                case SIOCSIFBRDADDR:
                case SIOCGIFNETMASK:
                case SIOCSIFNETMASK:
                case SIOCGIFDSTADDR:
                case SIOCSIFDSTADDR:
                case SIOCSIFPFLAGS:     
                case SIOCGIFPFLAGS:     
                case SIOCSIFFLAGS:
                        return(devinet_ioctl(cmd,(void *) arg));
                case SIOCGIFBR:
                case SIOCSIFBR:
#if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
#ifdef CONFIG_KMOD
                        if (br_ioctl_hook == NULL)
                                request_module("bridge");
#endif
                        if (br_ioctl_hook != NULL)
                                return br_ioctl_hook(arg);
#endif
                        return -ENOPKG;

                case SIOCGIFVLAN:
                case SIOCSIFVLAN:
#if defined(CONFIG_VLAN_8021Q) || defined(CONFIG_VLAN_8021Q_MODULE)
#ifdef CONFIG_KMOD
                        if (vlan_ioctl_hook == NULL)
                                request_module("8021q");
#endif
                        if (vlan_ioctl_hook != NULL)
                                return vlan_ioctl_hook(arg);
#endif
                        return -ENOPKG;

                case SIOCGIFDIVERT:
                case SIOCSIFDIVERT:
#ifdef CONFIG_NET_DIVERT
                        return divert_ioctl(cmd, (struct divert_cf *) arg);
#else
                        return -ENOPKG;
#endif  /* CONFIG_NET_DIVERT */
                        
                case SIOCADDDLCI:
                case SIOCDELDLCI:
#ifdef CONFIG_DLCI
                        lock_kernel();
                        err = dlci_ioctl(cmd, (void *) arg);
                        unlock_kernel();
                        return err;
#endif

#ifdef CONFIG_DLCI_MODULE

#ifdef CONFIG_KMOD
                        if (dlci_ioctl_hook == NULL)
                                request_module("dlci");
#endif

                        if (dlci_ioctl_hook) {
                                lock_kernel();
                                err = (*dlci_ioctl_hook)(cmd, (void *) arg);
                                unlock_kernel();
                                return err;
                        }
#endif
                        return -ENOPKG;

                default:
                        if ((cmd >= SIOCDEVPRIVATE) &&
                            (cmd <= (SIOCDEVPRIVATE + 15)))
                                return(dev_ioctl(cmd,(void *) arg));

#ifdef WIRELESS_EXT
                        if((cmd >= SIOCIWFIRST) && (cmd <= SIOCIWLAST))
                                return(dev_ioctl(cmd,(void *) arg));
#endif  /* WIRELESS_EXT */

                        if (sk->prot->ioctl==NULL || (err=sk->prot->ioctl(sk, cmd, arg))==-ENOIOCTLCMD)
                                return(dev_ioctl(cmd,(void *) arg));            
                        return err;
        }
        /*NOTREACHED*/
        return(0);
}

struct proto_ops inet_stream_ops = {
        family:         PF_INET,

        release:        inet_release,
        bind:           inet_bind,
        connect:        inet_stream_connect,
        socketpair:     sock_no_socketpair,
        accept:         inet_accept,
        getname:        inet_getname, 
        poll:           tcp_poll,
        ioctl:          inet_ioctl,
        listen:         inet_listen,
        shutdown:       inet_shutdown,
        setsockopt:     inet_setsockopt,
        getsockopt:     inet_getsockopt,
        sendmsg:        inet_sendmsg,
        recvmsg:        inet_recvmsg,
        mmap:           sock_no_mmap,
        sendpage:       tcp_sendpage
};

struct proto_ops inet_dgram_ops = {
        family:         PF_INET,

        release:        inet_release,
        bind:           inet_bind,
        connect:        inet_dgram_connect,
        socketpair:     sock_no_socketpair,
        accept:         sock_no_accept,
        getname:        inet_getname, 
        poll:           datagram_poll,
        ioctl:          inet_ioctl,
        listen:         sock_no_listen,
        shutdown:       inet_shutdown,
        setsockopt:     inet_setsockopt,
        getsockopt:     inet_getsockopt,
        sendmsg:        inet_sendmsg,
        recvmsg:        inet_recvmsg,
        mmap:           sock_no_mmap,
        sendpage:       sock_no_sendpage,
};

struct net_proto_family inet_family_ops = {
        family: PF_INET,
        create: inet_create
};


extern void tcp_init(void);
extern void tcp_v4_init(struct net_proto_family *);

/* Upon startup we insert all the elements in inetsw_array[] into
 * the linked list inetsw.
 */
static struct inet_protosw inetsw_array[] =
{
        {
                type:        SOCK_STREAM,
                protocol:    IPPROTO_TCP,
                prot:        &tcp_prot,
                ops:         &inet_stream_ops,
                capability:  -1,
                no_check:    0,
                flags:       INET_PROTOSW_PERMANENT,
        },

        {
                type:        SOCK_DGRAM,
                protocol:    IPPROTO_UDP,
                prot:        &udp_prot,
                ops:         &inet_dgram_ops,
                capability:  -1,
                no_check:    UDP_CSUM_DEFAULT,
                flags:       INET_PROTOSW_PERMANENT,
       },
        

       {
               type:        SOCK_RAW,
               protocol:    IPPROTO_IP, /* wild card */
               prot:        &raw_prot,
               ops:         &inet_dgram_ops,
               capability:  CAP_NET_RAW,
               no_check:    UDP_CSUM_DEFAULT,
               flags:       INET_PROTOSW_REUSE,
       }
};

#define INETSW_ARRAY_LEN (sizeof(inetsw_array) / sizeof(struct inet_protosw))

void
inet_register_protosw(struct inet_protosw *p)
{
        struct list_head *lh;
        struct inet_protosw *answer;
        int protocol = p->protocol;
        struct list_head *last_perm;

        br_write_lock_bh(BR_NETPROTO_LOCK);

        if (p->type > SOCK_MAX)
                goto out_illegal;

        /* If we are trying to override a permanent protocol, bail. */
        answer = NULL;
        last_perm = &inetsw[p->type];
        list_for_each(lh, &inetsw[p->type]) {
                answer = list_entry(lh, struct inet_protosw, list);

                /* Check only the non-wild match. */
                if (INET_PROTOSW_PERMANENT & answer->flags) {
                        if (protocol == answer->protocol)
                                break;
                        last_perm = lh;
                }

                answer = NULL;
        }
        if (answer)
                goto out_permanent;

        /* Add the new entry after the last permanent entry if any, so that
         * the new entry does not override a permanent entry when matched with
         * a wild-card protocol. But it is allowed to override any existing
         * non-permanent entry.  This means that when we remove this entry, the 
         * system automatically returns to the old behavior.
         */
        list_add(&p->list, last_perm);
out:
        br_write_unlock_bh(BR_NETPROTO_LOCK);
        return;

out_permanent:
        printk(KERN_ERR "Attempt to override permanent protocol %d.\n",
               protocol);
        goto out;

out_illegal:
        printk(KERN_ERR
               "Ignoring attempt to register illegal socket type %d.\n",
               p->type);
        goto out;
}

void
inet_unregister_protosw(struct inet_protosw *p)
{
        if (INET_PROTOSW_PERMANENT & p->flags) {
                printk(KERN_ERR
                       "Attempt to unregister permanent protocol %d.\n",
                       p->protocol);
        } else {
                br_write_lock_bh(BR_NETPROTO_LOCK);
                list_del(&p->list);
                br_write_unlock_bh(BR_NETPROTO_LOCK);
        }
}

extern void ipfrag_init(void);

/*
 *      Called by socket.c on kernel startup.  
 */
 
static int __init inet_init(void)
{
        struct sk_buff *dummy_skb;
        struct inet_protocol *p;
        struct inet_protosw *q;
        struct list_head *r;

        printk(KERN_INFO "NET4: Linux TCP/IP 1.0 for NET4.0\n");

        if (sizeof(struct inet_skb_parm) > sizeof(dummy_skb->cb)) {
                printk(KERN_CRIT "inet_proto_init: panic\n");
                return -EINVAL;
        }

        /*
         *      Tell SOCKET that we are alive... 
         */
   
        (void) sock_register(&inet_family_ops);

        /*
         *      Add all the protocols. 
         */

        printk(KERN_INFO "IP Protocols: ");
        for (p = inet_protocol_base; p != NULL;) {
                struct inet_protocol *tmp = (struct inet_protocol *) p->next;
                inet_add_protocol(p);
                printk("%s%s",p->name,tmp?", ":"\n");
                p = tmp;
        }

        /* Register the socket-side information for inet_create. */
        for(r = &inetsw[0]; r < &inetsw[SOCK_MAX]; ++r)
                INIT_LIST_HEAD(r);

        for(q = inetsw_array; q < &inetsw_array[INETSW_ARRAY_LEN]; ++q)
                inet_register_protosw(q);

        /*
         *      Set the ARP module up
         */

        arp_init();

        /*
         *      Set the IP module up
         */

        ip_init();

        tcp_v4_init(&inet_family_ops);

        /* Setup TCP slab cache for open requests. */
        tcp_init();


        /*
         *      Set the ICMP layer up
         */

        icmp_init(&inet_family_ops);

        /* I wish inet_add_protocol had no constructor hook...
           I had to move IPIP from net/ipv4/protocol.c :-( --ANK
         */
#ifdef CONFIG_NET_IPIP
        ipip_init();
#endif
#ifdef CONFIG_NET_IPGRE
        ipgre_init();
#endif

        /*
         *      Initialise the multicast router
         */
#if defined(CONFIG_IP_MROUTE)
        ip_mr_init();
#endif

        /*
         *      Create all the /proc entries.
         */
#ifdef CONFIG_PROC_FS
        proc_net_create ("raw", 0, raw_get_info);
        proc_net_create ("netstat", 0, netstat_get_info);
        proc_net_create ("snmp", 0, snmp_get_info);
        proc_net_create ("sockstat", 0, afinet_get_info);
        proc_net_create ("tcp", 0, tcp_get_info);
        proc_net_create ("udp", 0, udp_get_info);
#endif          /* CONFIG_PROC_FS */

        ipfrag_init();

        return 0;
}
module_init(inet_init);

---