udp.c 37.3 KB
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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.
 *
 *		The User Datagram Protocol (UDP).
 *
 * Version:	$Id: udp.c,v 1.102 2002/02/01 22:01:04 davem Exp $
 *
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 * Authors:	Ross Biro
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 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
 *		Alan Cox, <Alan.Cox@linux.org>
 *		Hirokazu Takahashi, <taka@valinux.co.jp>
 *
 * Fixes:
 *		Alan Cox	:	verify_area() calls
 *		Alan Cox	: 	stopped close while in use off icmp
 *					messages. Not a fix but a botch that
 *					for udp at least is 'valid'.
 *		Alan Cox	:	Fixed icmp handling properly
 *		Alan Cox	: 	Correct error for oversized datagrams
 *		Alan Cox	:	Tidied select() semantics. 
 *		Alan Cox	:	udp_err() fixed properly, also now 
 *					select and read wake correctly on errors
 *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
 *		Alan Cox	:	UDP can count its memory
 *		Alan Cox	:	send to an unknown connection causes
 *					an ECONNREFUSED off the icmp, but
 *					does NOT close.
 *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
 *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
 *					bug no longer crashes it.
 *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
 *		Alan Cox	:	Uses skb_free_datagram
 *		Alan Cox	:	Added get/set sockopt support.
 *		Alan Cox	:	Broadcasting without option set returns EACCES.
 *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
 *		Alan Cox	:	Use ip_tos and ip_ttl
 *		Alan Cox	:	SNMP Mibs
 *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
 *		Matt Dillon	:	UDP length checks.
 *		Alan Cox	:	Smarter af_inet used properly.
 *		Alan Cox	:	Use new kernel side addressing.
 *		Alan Cox	:	Incorrect return on truncated datagram receive.
 *	Arnt Gulbrandsen 	:	New udp_send and stuff
 *		Alan Cox	:	Cache last socket
 *		Alan Cox	:	Route cache
 *		Jon Peatfield	:	Minor efficiency fix to sendto().
 *		Mike Shaver	:	RFC1122 checks.
 *		Alan Cox	:	Nonblocking error fix.
 *	Willy Konynenberg	:	Transparent proxying support.
 *		Mike McLagan	:	Routing by source
 *		David S. Miller	:	New socket lookup architecture.
 *					Last socket cache retained as it
 *					does have a high hit rate.
 *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
 *		Andi Kleen	:	Some cleanups, cache destination entry
 *					for connect. 
 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
 *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
 *					return ENOTCONN for unconnected sockets (POSIX)
 *		Janos Farkas	:	don't deliver multi/broadcasts to a different
 *					bound-to-device socket
 *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
 *					datagrams.
 *	Hirokazu Takahashi	:	sendfile() on UDP works now.
 *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
 *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
 *					a single port at the same time.
 *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
 *
 *
 *		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 <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/config.h>
#include <linux/inet.h>
#include <linux/ipv6.h>
#include <linux/netdevice.h>
#include <net/snmp.h>
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#include <net/ip.h>
#include <net/tcp_states.h>
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#include <net/protocol.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/sock.h>
#include <net/udp.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/inet_common.h>
#include <net/checksum.h>
#include <net/xfrm.h>

/*
 *	Snmp MIB for the UDP layer
 */

116
DEFINE_SNMP_STAT(struct udp_mib, udp_statistics) __read_mostly;
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struct hlist_head udp_hash[UDP_HTABLE_SIZE];
DEFINE_RWLOCK(udp_hash_lock);

/* Shared by v4/v6 udp. */
int udp_port_rover;

static int udp_v4_get_port(struct sock *sk, unsigned short snum)
{
	struct hlist_node *node;
	struct sock *sk2;
	struct inet_sock *inet = inet_sk(sk);

	write_lock_bh(&udp_hash_lock);
	if (snum == 0) {
		int best_size_so_far, best, result, i;

		if (udp_port_rover > sysctl_local_port_range[1] ||
		    udp_port_rover < sysctl_local_port_range[0])
			udp_port_rover = sysctl_local_port_range[0];
		best_size_so_far = 32767;
		best = result = udp_port_rover;
		for (i = 0; i < UDP_HTABLE_SIZE; i++, result++) {
			struct hlist_head *list;
			int size;

			list = &udp_hash[result & (UDP_HTABLE_SIZE - 1)];
			if (hlist_empty(list)) {
				if (result > sysctl_local_port_range[1])
					result = sysctl_local_port_range[0] +
						((result - sysctl_local_port_range[0]) &
						 (UDP_HTABLE_SIZE - 1));
				goto gotit;
			}
			size = 0;
			sk_for_each(sk2, node, list)
				if (++size >= best_size_so_far)
					goto next;
			best_size_so_far = size;
			best = result;
		next:;
		}
		result = best;
		for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) {
			if (result > sysctl_local_port_range[1])
				result = sysctl_local_port_range[0]
					+ ((result - sysctl_local_port_range[0]) &
					   (UDP_HTABLE_SIZE - 1));
			if (!udp_lport_inuse(result))
				break;
		}
		if (i >= (1 << 16) / UDP_HTABLE_SIZE)
			goto fail;
gotit:
		udp_port_rover = snum = result;
	} else {
		sk_for_each(sk2, node,
			    &udp_hash[snum & (UDP_HTABLE_SIZE - 1)]) {
			struct inet_sock *inet2 = inet_sk(sk2);

			if (inet2->num == snum &&
			    sk2 != sk &&
			    !ipv6_only_sock(sk2) &&
			    (!sk2->sk_bound_dev_if ||
			     !sk->sk_bound_dev_if ||
			     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
			    (!inet2->rcv_saddr ||
			     !inet->rcv_saddr ||
			     inet2->rcv_saddr == inet->rcv_saddr) &&
			    (!sk2->sk_reuse || !sk->sk_reuse))
				goto fail;
		}
	}
	inet->num = snum;
	if (sk_unhashed(sk)) {
		struct hlist_head *h = &udp_hash[snum & (UDP_HTABLE_SIZE - 1)];

		sk_add_node(sk, h);
		sock_prot_inc_use(sk->sk_prot);
	}
	write_unlock_bh(&udp_hash_lock);
	return 0;

fail:
	write_unlock_bh(&udp_hash_lock);
	return 1;
}

static void udp_v4_hash(struct sock *sk)
{
	BUG();
}

static void udp_v4_unhash(struct sock *sk)
{
	write_lock_bh(&udp_hash_lock);
	if (sk_del_node_init(sk)) {
		inet_sk(sk)->num = 0;
		sock_prot_dec_use(sk->sk_prot);
	}
	write_unlock_bh(&udp_hash_lock);
}

/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 * harder than this. -DaveM
 */
static struct sock *udp_v4_lookup_longway(u32 saddr, u16 sport,
					  u32 daddr, u16 dport, int dif)
{
	struct sock *sk, *result = NULL;
	struct hlist_node *node;
	unsigned short hnum = ntohs(dport);
	int badness = -1;

	sk_for_each(sk, node, &udp_hash[hnum & (UDP_HTABLE_SIZE - 1)]) {
		struct inet_sock *inet = inet_sk(sk);

		if (inet->num == hnum && !ipv6_only_sock(sk)) {
			int score = (sk->sk_family == PF_INET ? 1 : 0);
			if (inet->rcv_saddr) {
				if (inet->rcv_saddr != daddr)
					continue;
				score+=2;
			}
			if (inet->daddr) {
				if (inet->daddr != saddr)
					continue;
				score+=2;
			}
			if (inet->dport) {
				if (inet->dport != sport)
					continue;
				score+=2;
			}
			if (sk->sk_bound_dev_if) {
				if (sk->sk_bound_dev_if != dif)
					continue;
				score+=2;
			}
			if(score == 9) {
				result = sk;
				break;
			} else if(score > badness) {
				result = sk;
				badness = score;
			}
		}
	}
	return result;
}

static __inline__ struct sock *udp_v4_lookup(u32 saddr, u16 sport,
					     u32 daddr, u16 dport, int dif)
{
	struct sock *sk;

	read_lock(&udp_hash_lock);
	sk = udp_v4_lookup_longway(saddr, sport, daddr, dport, dif);
	if (sk)
		sock_hold(sk);
	read_unlock(&udp_hash_lock);
	return sk;
}

static inline struct sock *udp_v4_mcast_next(struct sock *sk,
					     u16 loc_port, u32 loc_addr,
					     u16 rmt_port, u32 rmt_addr,
					     int dif)
{
	struct hlist_node *node;
	struct sock *s = sk;
	unsigned short hnum = ntohs(loc_port);

	sk_for_each_from(s, node) {
		struct inet_sock *inet = inet_sk(s);

		if (inet->num != hnum					||
		    (inet->daddr && inet->daddr != rmt_addr)		||
		    (inet->dport != rmt_port && inet->dport)		||
		    (inet->rcv_saddr && inet->rcv_saddr != loc_addr)	||
		    ipv6_only_sock(s)					||
		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
			continue;
		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
			continue;
		goto found;
  	}
	s = NULL;
found:
  	return s;
}

/*
 * This routine is called by the ICMP module when it gets some
 * sort of error condition.  If err < 0 then the socket should
 * be closed and the error returned to the user.  If err > 0
 * it's just the icmp type << 8 | icmp code.  
 * Header points to the ip header of the error packet. We move
 * on past this. Then (as it used to claim before adjustment)
 * header points to the first 8 bytes of the udp header.  We need
 * to find the appropriate port.
 */

void udp_err(struct sk_buff *skb, u32 info)
{
	struct inet_sock *inet;
	struct iphdr *iph = (struct iphdr*)skb->data;
	struct udphdr *uh = (struct udphdr*)(skb->data+(iph->ihl<<2));
	int type = skb->h.icmph->type;
	int code = skb->h.icmph->code;
	struct sock *sk;
	int harderr;
	int err;

	sk = udp_v4_lookup(iph->daddr, uh->dest, iph->saddr, uh->source, skb->dev->ifindex);
	if (sk == NULL) {
		ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
    	  	return;	/* No socket for error */
	}

	err = 0;
	harderr = 0;
	inet = inet_sk(sk);

	switch (type) {
	default:
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	case ICMP_SOURCE_QUENCH:
		goto out;
	case ICMP_PARAMETERPROB:
		err = EPROTO;
		harderr = 1;
		break;
	case ICMP_DEST_UNREACH:
		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
			if (inet->pmtudisc != IP_PMTUDISC_DONT) {
				err = EMSGSIZE;
				harderr = 1;
				break;
			}
			goto out;
		}
		err = EHOSTUNREACH;
		if (code <= NR_ICMP_UNREACH) {
			harderr = icmp_err_convert[code].fatal;
			err = icmp_err_convert[code].errno;
		}
		break;
	}

	/*
	 *      RFC1122: OK.  Passes ICMP errors back to application, as per 
	 *	4.1.3.3.
	 */
	if (!inet->recverr) {
		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
			goto out;
	} else {
		ip_icmp_error(sk, skb, err, uh->dest, info, (u8*)(uh+1));
	}
	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

/*
 * Throw away all pending data and cancel the corking. Socket is locked.
 */
static void udp_flush_pending_frames(struct sock *sk)
{
	struct udp_sock *up = udp_sk(sk);

	if (up->pending) {
		up->len = 0;
		up->pending = 0;
		ip_flush_pending_frames(sk);
	}
}

/*
 * Push out all pending data as one UDP datagram. Socket is locked.
 */
static int udp_push_pending_frames(struct sock *sk, struct udp_sock *up)
{
	struct inet_sock *inet = inet_sk(sk);
	struct flowi *fl = &inet->cork.fl;
	struct sk_buff *skb;
	struct udphdr *uh;
	int err = 0;

	/* Grab the skbuff where UDP header space exists. */
	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
		goto out;

	/*
	 * Create a UDP header
	 */
	uh = skb->h.uh;
	uh->source = fl->fl_ip_sport;
	uh->dest = fl->fl_ip_dport;
	uh->len = htons(up->len);
	uh->check = 0;

	if (sk->sk_no_check == UDP_CSUM_NOXMIT) {
		skb->ip_summed = CHECKSUM_NONE;
		goto send;
	}

	if (skb_queue_len(&sk->sk_write_queue) == 1) {
		/*
		 * Only one fragment on the socket.
		 */
		if (skb->ip_summed == CHECKSUM_HW) {
			skb->csum = offsetof(struct udphdr, check);
			uh->check = ~csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst,
					up->len, IPPROTO_UDP, 0);
		} else {
			skb->csum = csum_partial((char *)uh,
					sizeof(struct udphdr), skb->csum);
			uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst,
					up->len, IPPROTO_UDP, skb->csum);
			if (uh->check == 0)
				uh->check = -1;
		}
	} else {
		unsigned int csum = 0;
		/*
		 * HW-checksum won't work as there are two or more 
		 * fragments on the socket so that all csums of sk_buffs
		 * should be together.
		 */
		if (skb->ip_summed == CHECKSUM_HW) {
			int offset = (unsigned char *)uh - skb->data;
			skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);

			skb->ip_summed = CHECKSUM_NONE;
		} else {
			skb->csum = csum_partial((char *)uh,
					sizeof(struct udphdr), skb->csum);
		}

		skb_queue_walk(&sk->sk_write_queue, skb) {
			csum = csum_add(csum, skb->csum);
		}
		uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst,
				up->len, IPPROTO_UDP, csum);
		if (uh->check == 0)
			uh->check = -1;
	}
send:
	err = ip_push_pending_frames(sk);
out:
	up->len = 0;
	up->pending = 0;
	return err;
}


static unsigned short udp_check(struct udphdr *uh, int len, unsigned long saddr, unsigned long daddr, unsigned long base)
{
	return(csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base));
}

int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct udp_sock *up = udp_sk(sk);
	int ulen = len;
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	int free = 0;
	int connected = 0;
	u32 daddr, faddr, saddr;
	u16 dport;
	u8  tos;
	int err;
	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;

	if (len > 0xFFFF)
		return -EMSGSIZE;

	/* 
	 *	Check the flags.
	 */

	if (msg->msg_flags&MSG_OOB)	/* Mirror BSD error message compatibility */
		return -EOPNOTSUPP;

	ipc.opt = NULL;

	if (up->pending) {
		/*
		 * There are pending frames.
	 	 * The socket lock must be held while it's corked.
		 */
		lock_sock(sk);
		if (likely(up->pending)) {
			if (unlikely(up->pending != AF_INET)) {
				release_sock(sk);
				return -EINVAL;
			}
 			goto do_append_data;
		}
		release_sock(sk);
	}
	ulen += sizeof(struct udphdr);

	/*
	 *	Get and verify the address. 
	 */
	if (msg->msg_name) {
		struct sockaddr_in * usin = (struct sockaddr_in*)msg->msg_name;
		if (msg->msg_namelen < sizeof(*usin))
			return -EINVAL;
		if (usin->sin_family != AF_INET) {
			if (usin->sin_family != AF_UNSPEC)
				return -EAFNOSUPPORT;
		}

		daddr = usin->sin_addr.s_addr;
		dport = usin->sin_port;
		if (dport == 0)
			return -EINVAL;
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;
		daddr = inet->daddr;
		dport = inet->dport;
		/* Open fast path for connected socket.
		   Route will not be used, if at least one option is set.
		 */
		connected = 1;
  	}
	ipc.addr = inet->saddr;

	ipc.oif = sk->sk_bound_dev_if;
	if (msg->msg_controllen) {
		err = ip_cmsg_send(msg, &ipc);
		if (err)
			return err;
		if (ipc.opt)
			free = 1;
		connected = 0;
	}
	if (!ipc.opt)
		ipc.opt = inet->opt;

	saddr = ipc.addr;
	ipc.addr = faddr = daddr;

	if (ipc.opt && ipc.opt->srr) {
		if (!daddr)
			return -EINVAL;
		faddr = ipc.opt->faddr;
		connected = 0;
	}
	tos = RT_TOS(inet->tos);
	if (sock_flag(sk, SOCK_LOCALROUTE) ||
	    (msg->msg_flags & MSG_DONTROUTE) || 
	    (ipc.opt && ipc.opt->is_strictroute)) {
		tos |= RTO_ONLINK;
		connected = 0;
	}

	if (MULTICAST(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
		connected = 0;
	}

	if (connected)
		rt = (struct rtable*)sk_dst_check(sk, 0);

	if (rt == NULL) {
		struct flowi fl = { .oif = ipc.oif,
				    .nl_u = { .ip4_u =
					      { .daddr = faddr,
						.saddr = saddr,
						.tos = tos } },
				    .proto = IPPROTO_UDP,
				    .uli_u = { .ports =
					       { .sport = inet->sport,
						 .dport = dport } } };
		err = ip_route_output_flow(&rt, &fl, sk, !(msg->msg_flags&MSG_DONTWAIT));
		if (err)
			goto out;

		err = -EACCES;
		if ((rt->rt_flags & RTCF_BROADCAST) &&
		    !sock_flag(sk, SOCK_BROADCAST))
			goto out;
		if (connected)
			sk_dst_set(sk, dst_clone(&rt->u.dst));
	}

	if (msg->msg_flags&MSG_CONFIRM)
		goto do_confirm;
back_from_confirm:

	saddr = rt->rt_src;
	if (!ipc.addr)
		daddr = ipc.addr = rt->rt_dst;

	lock_sock(sk);
	if (unlikely(up->pending)) {
		/* The socket is already corked while preparing it. */
		/* ... which is an evident application bug. --ANK */
		release_sock(sk);

632
		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
L
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		err = -EINVAL;
		goto out;
	}
	/*
	 *	Now cork the socket to pend data.
	 */
	inet->cork.fl.fl4_dst = daddr;
	inet->cork.fl.fl_ip_dport = dport;
	inet->cork.fl.fl4_src = saddr;
	inet->cork.fl.fl_ip_sport = inet->sport;
	up->pending = AF_INET;

do_append_data:
	up->len += ulen;
	err = ip_append_data(sk, ip_generic_getfrag, msg->msg_iov, ulen, 
			sizeof(struct udphdr), &ipc, rt, 
			corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
	if (err)
		udp_flush_pending_frames(sk);
	else if (!corkreq)
		err = udp_push_pending_frames(sk, up);
	release_sock(sk);

out:
	ip_rt_put(rt);
	if (free)
		kfree(ipc.opt);
	if (!err) {
		UDP_INC_STATS_USER(UDP_MIB_OUTDATAGRAMS);
		return len;
	}
	return err;

do_confirm:
	dst_confirm(&rt->u.dst);
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}

static int udp_sendpage(struct sock *sk, struct page *page, int offset,
			size_t size, int flags)
{
	struct udp_sock *up = udp_sk(sk);
	int ret;

	if (!up->pending) {
		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };

		/* Call udp_sendmsg to specify destination address which
		 * sendpage interface can't pass.
		 * This will succeed only when the socket is connected.
		 */
		ret = udp_sendmsg(NULL, sk, &msg, 0);
		if (ret < 0)
			return ret;
	}

	lock_sock(sk);

	if (unlikely(!up->pending)) {
		release_sock(sk);

697
		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n");
L
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		return -EINVAL;
	}

	ret = ip_append_page(sk, page, offset, size, flags);
	if (ret == -EOPNOTSUPP) {
		release_sock(sk);
		return sock_no_sendpage(sk->sk_socket, page, offset,
					size, flags);
	}
	if (ret < 0) {
		udp_flush_pending_frames(sk);
		goto out;
	}

	up->len += size;
	if (!(up->corkflag || (flags&MSG_MORE)))
		ret = udp_push_pending_frames(sk, up);
	if (!ret)
		ret = size;
out:
	release_sock(sk);
	return ret;
}

/*
 *	IOCTL requests applicable to the UDP protocol
 */
 
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
	switch(cmd) 
	{
		case SIOCOUTQ:
		{
			int amount = atomic_read(&sk->sk_wmem_alloc);
			return put_user(amount, (int __user *)arg);
		}

		case SIOCINQ:
		{
			struct sk_buff *skb;
			unsigned long amount;

			amount = 0;
742
			spin_lock_bh(&sk->sk_receive_queue.lock);
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			skb = skb_peek(&sk->sk_receive_queue);
			if (skb != NULL) {
				/*
				 * We will only return the amount
				 * of this packet since that is all
				 * that will be read.
				 */
				amount = skb->len - sizeof(struct udphdr);
			}
752
			spin_unlock_bh(&sk->sk_receive_queue.lock);
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			return put_user(amount, (int __user *)arg);
		}

		default:
			return -ENOIOCTLCMD;
	}
	return(0);
}

static __inline__ int __udp_checksum_complete(struct sk_buff *skb)
{
	return (unsigned short)csum_fold(skb_checksum(skb, 0, skb->len, skb->csum));
}

static __inline__ int udp_checksum_complete(struct sk_buff *skb)
{
	return skb->ip_summed != CHECKSUM_UNNECESSARY &&
		__udp_checksum_complete(skb);
}

/*
 * 	This should be easy, if there is something there we
 * 	return it, otherwise we block.
 */

static int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		       size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
  	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
  	struct sk_buff *skb;
  	int copied, err;

	/*
	 *	Check any passed addresses
	 */
	if (addr_len)
		*addr_len=sizeof(*sin);

	if (flags & MSG_ERRQUEUE)
		return ip_recv_error(sk, msg, len);

try_again:
	skb = skb_recv_datagram(sk, flags, noblock, &err);
	if (!skb)
		goto out;
  
  	copied = skb->len - sizeof(struct udphdr);
	if (copied > len) {
		copied = len;
		msg->msg_flags |= MSG_TRUNC;
	}

	if (skb->ip_summed==CHECKSUM_UNNECESSARY) {
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov,
					      copied);
	} else if (msg->msg_flags&MSG_TRUNC) {
		if (__udp_checksum_complete(skb))
			goto csum_copy_err;
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov,
					      copied);
	} else {
		err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);

		if (err == -EINVAL)
			goto csum_copy_err;
	}

	if (err)
		goto out_free;

	sock_recv_timestamp(msg, sk, skb);

	/* Copy the address. */
	if (sin)
	{
		sin->sin_family = AF_INET;
		sin->sin_port = skb->h.uh->source;
		sin->sin_addr.s_addr = skb->nh.iph->saddr;
		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
  	}
	if (inet->cmsg_flags)
		ip_cmsg_recv(msg, skb);

	err = copied;
	if (flags & MSG_TRUNC)
		err = skb->len - sizeof(struct udphdr);
  
out_free:
  	skb_free_datagram(sk, skb);
out:
  	return err;

csum_copy_err:
	UDP_INC_STATS_BH(UDP_MIB_INERRORS);

	/* Clear queue. */
	if (flags&MSG_PEEK) {
		int clear = 0;
852
		spin_lock_bh(&sk->sk_receive_queue.lock);
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		if (skb == skb_peek(&sk->sk_receive_queue)) {
			__skb_unlink(skb, &sk->sk_receive_queue);
			clear = 1;
		}
857
		spin_unlock_bh(&sk->sk_receive_queue.lock);
L
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		if (clear)
			kfree_skb(skb);
	}

	skb_free_datagram(sk, skb);

	if (noblock)
		return -EAGAIN;	
	goto try_again;
}


int udp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
	/*
	 *	1003.1g - break association.
	 */
	 
	sk->sk_state = TCP_CLOSE;
	inet->daddr = 0;
	inet->dport = 0;
	sk->sk_bound_dev_if = 0;
	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
		sk->sk_prot->unhash(sk);
		inet->sport = 0;
	}
	sk_dst_reset(sk);
	return 0;
}

static void udp_close(struct sock *sk, long timeout)
{
	sk_common_release(sk);
}

/* return:
 * 	1  if the the UDP system should process it
 *	0  if we should drop this packet
 * 	-1 if it should get processed by xfrm4_rcv_encap
 */
static int udp_encap_rcv(struct sock * sk, struct sk_buff *skb)
{
#ifndef CONFIG_XFRM
	return 1; 
#else
	struct udp_sock *up = udp_sk(sk);
  	struct udphdr *uh = skb->h.uh;
	struct iphdr *iph;
	int iphlen, len;
  
	__u8 *udpdata = (__u8 *)uh + sizeof(struct udphdr);
	__u32 *udpdata32 = (__u32 *)udpdata;
	__u16 encap_type = up->encap_type;

	/* if we're overly short, let UDP handle it */
	if (udpdata > skb->tail)
		return 1;

	/* if this is not encapsulated socket, then just return now */
	if (!encap_type)
		return 1;

	len = skb->tail - udpdata;

	switch (encap_type) {
	default:
	case UDP_ENCAP_ESPINUDP:
		/* Check if this is a keepalive packet.  If so, eat it. */
		if (len == 1 && udpdata[0] == 0xff) {
			return 0;
		} else if (len > sizeof(struct ip_esp_hdr) && udpdata32[0] != 0 ) {
			/* ESP Packet without Non-ESP header */
			len = sizeof(struct udphdr);
		} else
			/* Must be an IKE packet.. pass it through */
			return 1;
		break;
	case UDP_ENCAP_ESPINUDP_NON_IKE:
		/* Check if this is a keepalive packet.  If so, eat it. */
		if (len == 1 && udpdata[0] == 0xff) {
			return 0;
		} else if (len > 2 * sizeof(u32) + sizeof(struct ip_esp_hdr) &&
			   udpdata32[0] == 0 && udpdata32[1] == 0) {
			
			/* ESP Packet with Non-IKE marker */
			len = sizeof(struct udphdr) + 2 * sizeof(u32);
		} else
			/* Must be an IKE packet.. pass it through */
			return 1;
		break;
	}

	/* At this point we are sure that this is an ESPinUDP packet,
	 * so we need to remove 'len' bytes from the packet (the UDP
	 * header and optional ESP marker bytes) and then modify the
	 * protocol to ESP, and then call into the transform receiver.
	 */
959 960
	if (skb_cloned(skb) && pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
		return 0;
L
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	/* Now we can update and verify the packet length... */
	iph = skb->nh.iph;
	iphlen = iph->ihl << 2;
	iph->tot_len = htons(ntohs(iph->tot_len) - len);
	if (skb->len < iphlen + len) {
		/* packet is too small!?! */
		return 0;
	}

	/* pull the data buffer up to the ESP header and set the
	 * transport header to point to ESP.  Keep UDP on the stack
	 * for later.
	 */
	skb->h.raw = skb_pull(skb, len);

	/* modify the protocol (it's ESP!) */
	iph->protocol = IPPROTO_ESP;

	/* and let the caller know to send this into the ESP processor... */
	return -1;
#endif
}

/* returns:
 *  -1: error
 *   0: success
 *  >0: "udp encap" protocol resubmission
 *
 * Note that in the success and error cases, the skb is assumed to
 * have either been requeued or freed.
 */
static int udp_queue_rcv_skb(struct sock * sk, struct sk_buff *skb)
{
	struct udp_sock *up = udp_sk(sk);

	/*
	 *	Charge it to the socket, dropping if the queue is full.
	 */
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb)) {
		kfree_skb(skb);
		return -1;
	}

	if (up->encap_type) {
		/*
		 * This is an encapsulation socket, so let's see if this is
		 * an encapsulated packet.
		 * If it's a keepalive packet, then just eat it.
		 * If it's an encapsulateed packet, then pass it to the
		 * IPsec xfrm input and return the response
		 * appropriately.  Otherwise, just fall through and
		 * pass this up the UDP socket.
		 */
		int ret;

		ret = udp_encap_rcv(sk, skb);
		if (ret == 0) {
			/* Eat the packet .. */
			kfree_skb(skb);
			return 0;
		}
		if (ret < 0) {
			/* process the ESP packet */
			ret = xfrm4_rcv_encap(skb, up->encap_type);
			UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS);
			return -ret;
		}
		/* FALLTHROUGH -- it's a UDP Packet */
	}

	if (sk->sk_filter && skb->ip_summed != CHECKSUM_UNNECESSARY) {
		if (__udp_checksum_complete(skb)) {
			UDP_INC_STATS_BH(UDP_MIB_INERRORS);
			kfree_skb(skb);
			return -1;
		}
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	}

	if (sock_queue_rcv_skb(sk,skb)<0) {
		UDP_INC_STATS_BH(UDP_MIB_INERRORS);
		kfree_skb(skb);
		return -1;
	}
	UDP_INC_STATS_BH(UDP_MIB_INDATAGRAMS);
	return 0;
}

/*
 *	Multicasts and broadcasts go to each listener.
 *
 *	Note: called only from the BH handler context,
 *	so we don't need to lock the hashes.
 */
static int udp_v4_mcast_deliver(struct sk_buff *skb, struct udphdr *uh,
				 u32 saddr, u32 daddr)
{
	struct sock *sk;
	int dif;

	read_lock(&udp_hash_lock);
	sk = sk_head(&udp_hash[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]);
	dif = skb->dev->ifindex;
	sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif);
	if (sk) {
		struct sock *sknext = NULL;

		do {
			struct sk_buff *skb1 = skb;

			sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr,
						   uh->source, saddr, dif);
			if(sknext)
				skb1 = skb_clone(skb, GFP_ATOMIC);

			if(skb1) {
				int ret = udp_queue_rcv_skb(sk, skb1);
				if (ret > 0)
					/* we should probably re-process instead
					 * of dropping packets here. */
					kfree_skb(skb1);
			}
			sk = sknext;
		} while(sknext);
	} else
		kfree_skb(skb);
	read_unlock(&udp_hash_lock);
	return 0;
}

/* Initialize UDP checksum. If exited with zero value (success),
 * CHECKSUM_UNNECESSARY means, that no more checks are required.
 * Otherwise, csum completion requires chacksumming packet body,
 * including udp header and folding it to skb->csum.
 */
static int udp_checksum_init(struct sk_buff *skb, struct udphdr *uh,
			     unsigned short ulen, u32 saddr, u32 daddr)
{
	if (uh->check == 0) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	} else if (skb->ip_summed == CHECKSUM_HW) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
		if (!udp_check(uh, ulen, saddr, daddr, skb->csum))
			return 0;
1106
		LIMIT_NETDEBUG(KERN_DEBUG "udp v4 hw csum failure.\n");
L
Linus Torvalds 已提交
1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184
		skb->ip_summed = CHECKSUM_NONE;
	}
	if (skb->ip_summed != CHECKSUM_UNNECESSARY)
		skb->csum = csum_tcpudp_nofold(saddr, daddr, ulen, IPPROTO_UDP, 0);
	/* Probably, we should checksum udp header (it should be in cache
	 * in any case) and data in tiny packets (< rx copybreak).
	 */
	return 0;
}

/*
 *	All we need to do is get the socket, and then do a checksum. 
 */
 
int udp_rcv(struct sk_buff *skb)
{
  	struct sock *sk;
  	struct udphdr *uh;
	unsigned short ulen;
	struct rtable *rt = (struct rtable*)skb->dst;
	u32 saddr = skb->nh.iph->saddr;
	u32 daddr = skb->nh.iph->daddr;
	int len = skb->len;

	/*
	 *	Validate the packet and the UDP length.
	 */
	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
		goto no_header;

	uh = skb->h.uh;

	ulen = ntohs(uh->len);

	if (ulen > len || ulen < sizeof(*uh))
		goto short_packet;

	if (pskb_trim(skb, ulen))
		goto short_packet;

	if (udp_checksum_init(skb, uh, ulen, saddr, daddr) < 0)
		goto csum_error;

	if(rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
		return udp_v4_mcast_deliver(skb, uh, saddr, daddr);

	sk = udp_v4_lookup(saddr, uh->source, daddr, uh->dest, skb->dev->ifindex);

	if (sk != NULL) {
		int ret = udp_queue_rcv_skb(sk, skb);
		sock_put(sk);

		/* a return value > 0 means to resubmit the input, but
		 * it it wants the return to be -protocol, or 0
		 */
		if (ret > 0)
			return -ret;
		return 0;
	}

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto drop;

	/* No socket. Drop packet silently, if checksum is wrong */
	if (udp_checksum_complete(skb))
		goto csum_error;

	UDP_INC_STATS_BH(UDP_MIB_NOPORTS);
	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	/*
	 * Hmm.  We got an UDP packet to a port to which we
	 * don't wanna listen.  Ignore it.
	 */
	kfree_skb(skb);
	return(0);

short_packet:
1185 1186 1187 1188 1189 1190 1191
	LIMIT_NETDEBUG(KERN_DEBUG "UDP: short packet: From %u.%u.%u.%u:%u %d/%d to %u.%u.%u.%u:%u\n",
		       NIPQUAD(saddr),
		       ntohs(uh->source),
		       ulen,
		       len,
		       NIPQUAD(daddr),
		       ntohs(uh->dest));
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no_header:
	UDP_INC_STATS_BH(UDP_MIB_INERRORS);
	kfree_skb(skb);
	return(0);

csum_error:
	/* 
	 * RFC1122: OK.  Discards the bad packet silently (as far as 
	 * the network is concerned, anyway) as per 4.1.3.4 (MUST). 
	 */
1202 1203 1204 1205 1206 1207
	LIMIT_NETDEBUG(KERN_DEBUG "UDP: bad checksum. From %d.%d.%d.%d:%d to %d.%d.%d.%d:%d ulen %d\n",
		       NIPQUAD(saddr),
		       ntohs(uh->source),
		       NIPQUAD(daddr),
		       ntohs(uh->dest),
		       ulen);
L
Linus Torvalds 已提交
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drop:
	UDP_INC_STATS_BH(UDP_MIB_INERRORS);
	kfree_skb(skb);
	return(0);
}

static int udp_destroy_sock(struct sock *sk)
{
	lock_sock(sk);
	udp_flush_pending_frames(sk);
	release_sock(sk);
	return 0;
}

/*
 *	Socket option code for UDP
 */
static int udp_setsockopt(struct sock *sk, int level, int optname, 
			  char __user *optval, int optlen)
{
	struct udp_sock *up = udp_sk(sk);
	int val;
	int err = 0;

	if (level != SOL_UDP)
		return ip_setsockopt(sk, level, optname, optval, optlen);

	if(optlen<sizeof(int))
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

	switch(optname) {
	case UDP_CORK:
		if (val != 0) {
			up->corkflag = 1;
		} else {
			up->corkflag = 0;
			lock_sock(sk);
			udp_push_pending_frames(sk, up);
			release_sock(sk);
		}
		break;
		
	case UDP_ENCAP:
		switch (val) {
		case 0:
		case UDP_ENCAP_ESPINUDP:
		case UDP_ENCAP_ESPINUDP_NON_IKE:
			up->encap_type = val;
			break;
		default:
			err = -ENOPROTOOPT;
			break;
		}
		break;

	default:
		err = -ENOPROTOOPT;
		break;
	};

	return err;
}

static int udp_getsockopt(struct sock *sk, int level, int optname, 
			  char __user *optval, int __user *optlen)
{
	struct udp_sock *up = udp_sk(sk);
	int val, len;

	if (level != SOL_UDP)
		return ip_getsockopt(sk, level, optname, optval, optlen);

	if(get_user(len,optlen))
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));
	
	if(len < 0)
		return -EINVAL;

	switch(optname) {
	case UDP_CORK:
		val = up->corkflag;
		break;

	case UDP_ENCAP:
		val = up->encap_type;
		break;

	default:
		return -ENOPROTOOPT;
	};

  	if(put_user(len, optlen))
  		return -EFAULT;
	if(copy_to_user(optval, &val,len))
		return -EFAULT;
  	return 0;
}

/**
 * 	udp_poll - wait for a UDP event.
 *	@file - file struct
 *	@sock - socket
 *	@wait - poll table
 *
 *	This is same as datagram poll, except for the special case of 
 *	blocking sockets. If application is using a blocking fd
 *	and a packet with checksum error is in the queue;
 *	then it could get return from select indicating data available
 *	but then block when reading it. Add special case code
 *	to work around these arguably broken applications.
 */
unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask = datagram_poll(file, sock, wait);
	struct sock *sk = sock->sk;
	
	/* Check for false positives due to checksum errors */
	if ( (mask & POLLRDNORM) &&
	     !(file->f_flags & O_NONBLOCK) &&
	     !(sk->sk_shutdown & RCV_SHUTDOWN)){
		struct sk_buff_head *rcvq = &sk->sk_receive_queue;
		struct sk_buff *skb;

1336
		spin_lock_bh(&rcvq->lock);
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		while ((skb = skb_peek(rcvq)) != NULL) {
			if (udp_checksum_complete(skb)) {
				UDP_INC_STATS_BH(UDP_MIB_INERRORS);
				__skb_unlink(skb, rcvq);
				kfree_skb(skb);
			} else {
				skb->ip_summed = CHECKSUM_UNNECESSARY;
				break;
			}
		}
1347
		spin_unlock_bh(&rcvq->lock);
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		/* nothing to see, move along */
		if (skb == NULL)
			mask &= ~(POLLIN | POLLRDNORM);
	}

	return mask;
	
}

struct proto udp_prot = {
 	.name =		"UDP",
	.owner =	THIS_MODULE,
	.close =	udp_close,
	.connect =	ip4_datagram_connect,
	.disconnect =	udp_disconnect,
	.ioctl =	udp_ioctl,
	.destroy =	udp_destroy_sock,
	.setsockopt =	udp_setsockopt,
	.getsockopt =	udp_getsockopt,
	.sendmsg =	udp_sendmsg,
	.recvmsg =	udp_recvmsg,
	.sendpage =	udp_sendpage,
	.backlog_rcv =	udp_queue_rcv_skb,
	.hash =		udp_v4_hash,
	.unhash =	udp_v4_unhash,
	.get_port =	udp_v4_get_port,
	.obj_size =	sizeof(struct udp_sock),
};

/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS

static struct sock *udp_get_first(struct seq_file *seq)
{
	struct sock *sk;
	struct udp_iter_state *state = seq->private;

	for (state->bucket = 0; state->bucket < UDP_HTABLE_SIZE; ++state->bucket) {
		struct hlist_node *node;
		sk_for_each(sk, node, &udp_hash[state->bucket]) {
			if (sk->sk_family == state->family)
				goto found;
		}
	}
	sk = NULL;
found:
	return sk;
}

static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
{
	struct udp_iter_state *state = seq->private;

	do {
		sk = sk_next(sk);
try_again:
		;
	} while (sk && sk->sk_family != state->family);

	if (!sk && ++state->bucket < UDP_HTABLE_SIZE) {
		sk = sk_head(&udp_hash[state->bucket]);
		goto try_again;
	}
	return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
	struct sock *sk = udp_get_first(seq);

	if (sk)
		while(pos && (sk = udp_get_next(seq, sk)) != NULL)
			--pos;
	return pos ? NULL : sk;
}

static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
	read_lock(&udp_hash_lock);
	return *pos ? udp_get_idx(seq, *pos-1) : (void *)1;
}

static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct sock *sk;

	if (v == (void *)1)
		sk = udp_get_idx(seq, 0);
	else
		sk = udp_get_next(seq, v);

	++*pos;
	return sk;
}

static void udp_seq_stop(struct seq_file *seq, void *v)
{
	read_unlock(&udp_hash_lock);
}

static int udp_seq_open(struct inode *inode, struct file *file)
{
	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
	struct seq_file *seq;
	int rc = -ENOMEM;
	struct udp_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);

	if (!s)
		goto out;
	memset(s, 0, sizeof(*s));
	s->family		= afinfo->family;
	s->seq_ops.start	= udp_seq_start;
	s->seq_ops.next		= udp_seq_next;
	s->seq_ops.show		= afinfo->seq_show;
	s->seq_ops.stop		= udp_seq_stop;

	rc = seq_open(file, &s->seq_ops);
	if (rc)
		goto out_kfree;

	seq	     = file->private_data;
	seq->private = s;
out:
	return rc;
out_kfree:
	kfree(s);
	goto out;
}

/* ------------------------------------------------------------------------ */
int udp_proc_register(struct udp_seq_afinfo *afinfo)
{
	struct proc_dir_entry *p;
	int rc = 0;

	if (!afinfo)
		return -EINVAL;
	afinfo->seq_fops->owner		= afinfo->owner;
	afinfo->seq_fops->open		= udp_seq_open;
	afinfo->seq_fops->read		= seq_read;
	afinfo->seq_fops->llseek	= seq_lseek;
	afinfo->seq_fops->release	= seq_release_private;

	p = proc_net_fops_create(afinfo->name, S_IRUGO, afinfo->seq_fops);
	if (p)
		p->data = afinfo;
	else
		rc = -ENOMEM;
	return rc;
}

void udp_proc_unregister(struct udp_seq_afinfo *afinfo)
{
	if (!afinfo)
		return;
	proc_net_remove(afinfo->name);
	memset(afinfo->seq_fops, 0, sizeof(*afinfo->seq_fops));
}

/* ------------------------------------------------------------------------ */
static void udp4_format_sock(struct sock *sp, char *tmpbuf, int bucket)
{
	struct inet_sock *inet = inet_sk(sp);
	unsigned int dest = inet->daddr;
	unsigned int src  = inet->rcv_saddr;
	__u16 destp	  = ntohs(inet->dport);
	__u16 srcp	  = ntohs(inet->sport);

	sprintf(tmpbuf, "%4d: %08X:%04X %08X:%04X"
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p",
		bucket, src, srcp, dest, destp, sp->sk_state, 
		atomic_read(&sp->sk_wmem_alloc),
		atomic_read(&sp->sk_rmem_alloc),
		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
		atomic_read(&sp->sk_refcnt), sp);
}

static int udp4_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_printf(seq, "%-127s\n",
			   "  sl  local_address rem_address   st tx_queue "
			   "rx_queue tr tm->when retrnsmt   uid  timeout "
			   "inode");
	else {
		char tmpbuf[129];
		struct udp_iter_state *state = seq->private;

		udp4_format_sock(v, tmpbuf, state->bucket);
		seq_printf(seq, "%-127s\n", tmpbuf);
	}
	return 0;
}

/* ------------------------------------------------------------------------ */
static struct file_operations udp4_seq_fops;
static struct udp_seq_afinfo udp4_seq_afinfo = {
	.owner		= THIS_MODULE,
	.name		= "udp",
	.family		= AF_INET,
	.seq_show	= udp4_seq_show,
	.seq_fops	= &udp4_seq_fops,
};

int __init udp4_proc_init(void)
{
	return udp_proc_register(&udp4_seq_afinfo);
}

void udp4_proc_exit(void)
{
	udp_proc_unregister(&udp4_seq_afinfo);
}
#endif /* CONFIG_PROC_FS */

EXPORT_SYMBOL(udp_disconnect);
EXPORT_SYMBOL(udp_hash);
EXPORT_SYMBOL(udp_hash_lock);
EXPORT_SYMBOL(udp_ioctl);
EXPORT_SYMBOL(udp_port_rover);
EXPORT_SYMBOL(udp_prot);
EXPORT_SYMBOL(udp_sendmsg);
EXPORT_SYMBOL(udp_poll);

#ifdef CONFIG_PROC_FS
EXPORT_SYMBOL(udp_proc_register);
EXPORT_SYMBOL(udp_proc_unregister);
#endif