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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 1.1.1.1 2004-04-15 01:13:53 phoenix 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);