xnu-344.21.74.tar.gz

[apple/xnu.git] / bsd / netinet / udp_usrreq.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)udp_usrreq.c	8.6 (Berkeley) 5/23/95
 * $FreeBSD: src/sys/netinet/udp_usrreq.c,v 1.64.2.13 2001/08/08 18:59:54 ghelmer Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#if INET6
#include <netinet/ip6.h>
#endif
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#if INET6
#include <netinet6/ip6_var.h>
#endif
#include <netinet/ip_icmp.h>
#include <netinet/icmp_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <sys/kdebug.h>

#if IPSEC
#include <netinet6/ipsec.h>
extern int ipsec_bypass;
#endif /*IPSEC*/


#define DBG_LAYER_IN_BEG	NETDBG_CODE(DBG_NETUDP, 0)
#define DBG_LAYER_IN_END	NETDBG_CODE(DBG_NETUDP, 2)
#define DBG_LAYER_OUT_BEG	NETDBG_CODE(DBG_NETUDP, 1)
#define DBG_LAYER_OUT_END	NETDBG_CODE(DBG_NETUDP, 3)
#define DBG_FNC_UDP_INPUT	NETDBG_CODE(DBG_NETUDP, (5 << 8))
#define DBG_FNC_UDP_OUTPUT	NETDBG_CODE(DBG_NETUDP, (6 << 8) | 1)


#define __STDC__ 1
/*
 * UDP protocol implementation.
 * Per RFC 768, August, 1980.
 */
#ifndef	COMPAT_42
static int	udpcksum = 1;
#else
static int	udpcksum = 0;		/* XXX */
#endif
SYSCTL_INT(_net_inet_udp, UDPCTL_CHECKSUM, checksum, CTLFLAG_RW,
		&udpcksum, 0, "");

int	log_in_vain = 0;
SYSCTL_INT(_net_inet_udp, OID_AUTO, log_in_vain, CTLFLAG_RW, 
    &log_in_vain, 0, "Log all incoming UDP packets");

static int	blackhole = 0;
SYSCTL_INT(_net_inet_udp, OID_AUTO, blackhole, CTLFLAG_RW,
	&blackhole, 0, "Do not send port unreachables for refused connects");

struct	inpcbhead udb;		/* from udp_var.h */
#define	udb6	udb  /* for KAME src sync over BSD*'s */
struct	inpcbinfo udbinfo;

#ifndef UDBHASHSIZE
#define UDBHASHSIZE 16
#endif

extern  int apple_hwcksum_rx;

struct	udpstat udpstat;	/* from udp_var.h */
SYSCTL_STRUCT(_net_inet_udp, UDPCTL_STATS, stats, CTLFLAG_RD,
    &udpstat, udpstat, "UDP statistics (struct udpstat, netinet/udp_var.h)");

static struct	sockaddr_in udp_in = { sizeof(udp_in), AF_INET };
#if INET6
struct udp_in6 {
	struct sockaddr_in6	uin6_sin;
	u_char			uin6_init_done : 1;
} udp_in6 = {
	{ sizeof(udp_in6.uin6_sin), AF_INET6 },
	0
};
struct udp_ip6 {
	struct ip6_hdr		uip6_ip6;
	u_char			uip6_init_done : 1;
} udp_ip6;
#endif /* INET6 */

static void udp_append __P((struct inpcb *last, struct ip *ip,
			    struct mbuf *n, int off));
#if INET6
static void ip_2_ip6_hdr __P((struct ip6_hdr *ip6, struct ip *ip));
#endif

static int udp_detach __P((struct socket *so));
static	int udp_output __P((struct inpcb *, struct mbuf *, struct sockaddr *,
			    struct mbuf *, struct proc *));

void
udp_init()
{
    	vm_size_t	str_size;
	int             stat;
	u_char		fake_owner;
	struct in_addr  laddr;
	struct in_addr  faddr;
	u_short		lport;

	LIST_INIT(&udb);
	udbinfo.listhead = &udb;
	udbinfo.hashbase = hashinit(UDBHASHSIZE, M_PCB, &udbinfo.hashmask);
	udbinfo.porthashbase = hashinit(UDBHASHSIZE, M_PCB,
					&udbinfo.porthashmask);
#ifdef __APPLE__
	str_size = (vm_size_t) sizeof(struct inpcb);
	udbinfo.ipi_zone = (void *) zinit(str_size, 80000*str_size, 8192, "udpcb");

	udbinfo.last_pcb = 0;
	in_pcb_nat_init(&udbinfo, AF_INET, IPPROTO_UDP, SOCK_DGRAM);
#else
	udbinfo.ipi_zone = zinit("udpcb", sizeof(struct inpcb), maxsockets,
				 ZONE_INTERRUPT, 0);
#endif

#if 0
	/* for pcb sharing testing only */
	stat = in_pcb_new_share_client(&udbinfo, &fake_owner);
	kprintf("udp_init in_pcb_new_share_client - stat = %d\n", stat);

	laddr.s_addr = 0x11646464;
	faddr.s_addr = 0x11646465;
	
	lport = 1500;
	in_pcb_grab_port(&udbinfo, 0, laddr, &lport, faddr, 1600, 0, fake_owner); 
	kprintf("udp_init in_pcb_grab_port - stat = %d\n", stat);

	stat = in_pcb_rem_share_client(&udbinfo, fake_owner);
	kprintf("udp_init in_pcb_rem_share_client - stat = %d\n", stat);

	stat = in_pcb_new_share_client(&udbinfo, &fake_owner);
	kprintf("udp_init in_pcb_new_share_client(2) - stat = %d\n", stat);

	laddr.s_addr = 0x11646464;
	faddr.s_addr = 0x11646465;
	
	lport = 1500;
	stat = in_pcb_grab_port(&udbinfo, 0, laddr, &lport, faddr, 1600, 0, fake_owner); 
	kprintf("udp_init in_pcb_grab_port(2) - stat = %d\n", stat);
#endif
}

void
udp_input(m, iphlen)
	register struct mbuf *m;
	int iphlen;
{
	register struct ip *ip;
	register struct udphdr *uh;
	register struct inpcb *inp;
	struct mbuf *opts = 0;
	int len;
	struct ip save_ip;
	struct sockaddr *append_sa;

	udpstat.udps_ipackets++;

	KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_START, 0,0,0,0,0);
	if (m->m_pkthdr.csum_flags & CSUM_TCP_SUM16)
		m->m_pkthdr.csum_flags = 0; /* invalidate hwcksum for UDP */

	/*
	 * Strip IP options, if any; should skip this,
	 * make available to user, and use on returned packets,
	 * but we don't yet have a way to check the checksum
	 * with options still present.
	 */
	if (iphlen > sizeof (struct ip)) {
		ip_stripoptions(m, (struct mbuf *)0);
		iphlen = sizeof(struct ip);
	}

	/*
	 * Get IP and UDP header together in first mbuf.
	 */
	ip = mtod(m, struct ip *);
	if (m->m_len < iphlen + sizeof(struct udphdr)) {
		if ((m = m_pullup(m, iphlen + sizeof(struct udphdr))) == 0) {
			udpstat.udps_hdrops++;
			KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
			return;
		}
		ip = mtod(m, struct ip *);
	}
	uh = (struct udphdr *)((caddr_t)ip + iphlen);

	/* destination port of 0 is illegal, based on RFC768. */
	if (uh->uh_dport == 0)
		goto bad;

	KERNEL_DEBUG(DBG_LAYER_IN_BEG, uh->uh_dport, uh->uh_sport,
		     ip->ip_src.s_addr, ip->ip_dst.s_addr, uh->uh_ulen);

	/*
	 * Make mbuf data length reflect UDP length.
	 * If not enough data to reflect UDP length, drop.
	 */
	len = ntohs((u_short)uh->uh_ulen);
	if (ip->ip_len != len) {
		if (len > ip->ip_len || len < sizeof(struct udphdr)) {
			udpstat.udps_badlen++;
			goto bad;
		}
		m_adj(m, len - ip->ip_len);
		/* ip->ip_len = len; */
	}
	/*
	 * Save a copy of the IP header in case we want restore it
	 * for sending an ICMP error message in response.
	 */
	save_ip = *ip;

	/*
	 * Checksum extended UDP header and data.
	 */
	if (uh->uh_sum) {
               if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
                        if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
                                uh->uh_sum = m->m_pkthdr.csum_data;
                        else
			    goto doudpcksum;
                      uh->uh_sum ^= 0xffff;
                } else {
doudpcksum:
			bzero(((struct ipovly *)ip)->ih_x1, 9);
			((struct ipovly *)ip)->ih_len = uh->uh_ulen;
			uh->uh_sum = in_cksum(m, len + sizeof (struct ip));
		}
		if (uh->uh_sum) {
			udpstat.udps_badsum++;
			m_freem(m);
			KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
			return;
		}
	}
#ifndef __APPLE__
	 else
		udpstat.udps_nosum++;
#endif

	if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
	    in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) {
		struct inpcb *last;
		/*
		 * Deliver a multicast or broadcast datagram to *all* sockets
		 * for which the local and remote addresses and ports match
		 * those of the incoming datagram.  This allows more than
		 * one process to receive multi/broadcasts on the same port.
		 * (This really ought to be done for unicast datagrams as
		 * well, but that would cause problems with existing
		 * applications that open both address-specific sockets and
		 * a wildcard socket listening to the same port -- they would
		 * end up receiving duplicates of every unicast datagram.
		 * Those applications open the multiple sockets to overcome an
		 * inadequacy of the UDP socket interface, but for backwards
		 * compatibility we avoid the problem here rather than
		 * fixing the interface.  Maybe 4.5BSD will remedy this?)
		 */

		/*
		 * Construct sockaddr format source address.
		 */
		udp_in.sin_port = uh->uh_sport;
		udp_in.sin_addr = ip->ip_src;
		/*
		 * Locate pcb(s) for datagram.
		 * (Algorithm copied from raw_intr().)
		 */
		last = NULL;
#if INET6
		udp_in6.uin6_init_done = udp_ip6.uip6_init_done = 0;
#endif
		LIST_FOREACH(inp, &udb, inp_list) {
#ifdef __APPLE__
			/* Ignore nat/SharedIP dummy pcbs */
			if (inp->inp_socket == &udbinfo.nat_dummy_socket)
				continue;
#endif
#if INET6
			if ((inp->inp_vflag & INP_IPV4) == 0)
				continue;
#endif
			if (inp->inp_lport != uh->uh_dport)
				continue;
			if (inp->inp_laddr.s_addr != INADDR_ANY) {
				if (inp->inp_laddr.s_addr !=
				    ip->ip_dst.s_addr)
					continue;
			}
			if (inp->inp_faddr.s_addr != INADDR_ANY) {
				if (inp->inp_faddr.s_addr !=
				    ip->ip_src.s_addr ||
				    inp->inp_fport != uh->uh_sport)
					continue;
			}

			if (last != NULL) {
				struct mbuf *n;

#if IPSEC
				/* check AH/ESP integrity. */
				if (ipsec_bypass == 0 && ipsec4_in_reject_so(m, last->inp_socket)) {
					ipsecstat.in_polvio++;
					/* do not inject data to pcb */
				} else
#endif /*IPSEC*/
				if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
					udp_append(last, ip, n,
						   iphlen +
						   sizeof(struct udphdr));
				}
			}
			last = inp;
			/*
			 * Don't look for additional matches if this one does
			 * not have either the SO_REUSEPORT or SO_REUSEADDR
			 * socket options set.  This heuristic avoids searching
			 * through all pcbs in the common case of a non-shared
			 * port.  It * assumes that an application will never
			 * clear these options after setting them.
			 */
			if ((last->inp_socket->so_options&(SO_REUSEPORT|SO_REUSEADDR)) == 0)
				break;
		}

		if (last == NULL) {
			/*
			 * No matching pcb found; discard datagram.
			 * (No need to send an ICMP Port Unreachable
			 * for a broadcast or multicast datgram.)
			 */
			udpstat.udps_noportbcast++;
			goto bad;
		}
#if IPSEC
		/* check AH/ESP integrity. */
		if (ipsec_bypass == 0 && m && ipsec4_in_reject_so(m, last->inp_socket)) {
			ipsecstat.in_polvio++;
			goto bad;
		}
#endif /*IPSEC*/
		udp_append(last, ip, m, iphlen + sizeof(struct udphdr));
		return;
	}
	/*
	 * Locate pcb for datagram.
	 */
	inp = in_pcblookup_hash(&udbinfo, ip->ip_src, uh->uh_sport,
	    ip->ip_dst, uh->uh_dport, 1, m->m_pkthdr.rcvif);
	if (inp == NULL) {
		if (log_in_vain) {
			char buf[4*sizeof "123"];

			strcpy(buf, inet_ntoa(ip->ip_dst));
			log(LOG_INFO,
			    "Connection attempt to UDP %s:%d from %s:%d\n",
			    buf, ntohs(uh->uh_dport), inet_ntoa(ip->ip_src),
			    ntohs(uh->uh_sport));
		}
		udpstat.udps_noport++;
		if (m->m_flags & (M_BCAST | M_MCAST)) {
			udpstat.udps_noportbcast++;
			goto bad;
		}
#if ICMP_BANDLIM
		if (badport_bandlim(BANDLIM_ICMP_UNREACH) < 0)
			goto bad;
#endif
		if (blackhole)
			goto bad;
		*ip = save_ip;
		ip->ip_len += iphlen;
		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0);
		KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
		return;
	}
#if IPSEC
	if (ipsec_bypass == 0 && inp != NULL && ipsec4_in_reject_so(m, inp->inp_socket)) {
		ipsecstat.in_polvio++;
		goto bad;
	}
#endif /*IPSEC*/

	/*
	 * Construct sockaddr format source address.
	 * Stuff source address and datagram in user buffer.
	 */
	udp_in.sin_port = uh->uh_sport;
	udp_in.sin_addr = ip->ip_src;
	if (inp->inp_flags & INP_CONTROLOPTS
	    || inp->inp_socket->so_options & SO_TIMESTAMP) {
#if INET6
		if (inp->inp_vflag & INP_IPV6) {
			int savedflags;

			ip_2_ip6_hdr(&udp_ip6.uip6_ip6, ip);
			savedflags = inp->inp_flags;
			inp->inp_flags &= ~INP_UNMAPPABLEOPTS;
			ip6_savecontrol(inp, &opts, &udp_ip6.uip6_ip6, m);
			inp->inp_flags = savedflags;
		} else
#endif
		ip_savecontrol(inp, &opts, ip, m);
	}
 	m_adj(m, iphlen + sizeof(struct udphdr));

	KERNEL_DEBUG(DBG_LAYER_IN_END, uh->uh_dport, uh->uh_sport,
		     save_ip.ip_src.s_addr, save_ip.ip_dst.s_addr, uh->uh_ulen);

#if INET6
	if (inp->inp_vflag & INP_IPV6) {
		in6_sin_2_v4mapsin6(&udp_in, &udp_in6.uin6_sin);
		append_sa = (struct sockaddr *)&udp_in6;
	} else
#endif
	append_sa = (struct sockaddr *)&udp_in;
	if (sbappendaddr(&inp->inp_socket->so_rcv, append_sa, m, opts) == 0) {
		udpstat.udps_fullsock++;
		goto bad;
	}
	sorwakeup(inp->inp_socket);
	KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
	return;
bad:
	m_freem(m);
	if (opts)
		m_freem(opts);
	KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
	return;
}

#if INET6
static void
ip_2_ip6_hdr(ip6, ip)
	struct ip6_hdr *ip6;
	struct ip *ip;
{
	bzero(ip6, sizeof(*ip6));

	ip6->ip6_vfc = IPV6_VERSION;
	ip6->ip6_plen = ip->ip_len;
	ip6->ip6_nxt = ip->ip_p;
	ip6->ip6_hlim = ip->ip_ttl;
	ip6->ip6_src.s6_addr32[2] = ip6->ip6_dst.s6_addr32[2] =
		IPV6_ADDR_INT32_SMP;
	ip6->ip6_src.s6_addr32[3] = ip->ip_src.s_addr;
	ip6->ip6_dst.s6_addr32[3] = ip->ip_dst.s_addr;
}
#endif

/*
 * subroutine of udp_input(), mainly for source code readability.
 * caller must properly init udp_ip6 and udp_in6 beforehand.
 */
static void
udp_append(last, ip, n, off)
	struct inpcb *last;
	struct ip *ip;
	struct mbuf *n;
	int off;
{
	struct sockaddr *append_sa;
	struct mbuf *opts = 0;

	if (last->inp_flags & INP_CONTROLOPTS ||
	    last->inp_socket->so_options & SO_TIMESTAMP) {
#if INET6
		if (last->inp_vflag & INP_IPV6) {
			int savedflags;

			if (udp_ip6.uip6_init_done == 0) {
				ip_2_ip6_hdr(&udp_ip6.uip6_ip6, ip);
				udp_ip6.uip6_init_done = 1;
			}
			savedflags = last->inp_flags;
			last->inp_flags &= ~INP_UNMAPPABLEOPTS;
			ip6_savecontrol(last, &opts, &udp_ip6.uip6_ip6, n);
			last->inp_flags = savedflags;
		} else
#endif
		ip_savecontrol(last, &opts, ip, n);
	}
#if INET6
	if (last->inp_vflag & INP_IPV6) {
		if (udp_in6.uin6_init_done == 0) {
			in6_sin_2_v4mapsin6(&udp_in, &udp_in6.uin6_sin);
			udp_in6.uin6_init_done = 1;
		}
		append_sa = (struct sockaddr *)&udp_in6.uin6_sin;
	} else
#endif
	append_sa = (struct sockaddr *)&udp_in;
	m_adj(n, off);
	if (sbappendaddr(&last->inp_socket->so_rcv, append_sa, n, opts) == 0) {
		m_freem(n);
		if (opts)
			m_freem(opts);
		udpstat.udps_fullsock++;
	} else
		sorwakeup(last->inp_socket);
}

/*
 * Notify a udp user of an asynchronous error;
 * just wake up so that he can collect error status.
 */
void
udp_notify(inp, errno)
	register struct inpcb *inp;
	int errno;
{
	inp->inp_socket->so_error = errno;
	sorwakeup(inp->inp_socket);
	sowwakeup(inp->inp_socket);
}

void
udp_ctlinput(cmd, sa, vip)
	int cmd;
	struct sockaddr *sa;
	void *vip;
{
	struct ip *ip = vip;
	struct udphdr *uh;
	void (*notify) __P((struct inpcb *, int)) = udp_notify;
        struct in_addr faddr;
	struct inpcb *inp;
	int s;

	faddr = ((struct sockaddr_in *)sa)->sin_addr;
	if (sa->sa_family != AF_INET || faddr.s_addr == INADDR_ANY)
        	return;

	if (PRC_IS_REDIRECT(cmd)) {
		ip = 0;
		notify = in_rtchange;
	} else if (cmd == PRC_HOSTDEAD)
		ip = 0;
	else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
		return;
	if (ip) {
		s = splnet();
		uh = (struct udphdr *)((caddr_t)ip + (ip->ip_hl << 2));
		inp = in_pcblookup_hash(&udbinfo, faddr, uh->uh_dport,
                    ip->ip_src, uh->uh_sport, 0, NULL);
		if (inp != NULL && inp->inp_socket != NULL)
			(*notify)(inp, inetctlerrmap[cmd]);
		splx(s);
	} else
		in_pcbnotifyall(&udb, faddr, inetctlerrmap[cmd], notify);
}

static int
udp_pcblist SYSCTL_HANDLER_ARGS
{
	int error, i, n, s;
	struct inpcb *inp, **inp_list;
	inp_gen_t gencnt;
	struct xinpgen xig;

	/*
	 * The process of preparing the TCB list is too time-consuming and
	 * resource-intensive to repeat twice on every request.
	 */
	if (req->oldptr == 0) {
		n = udbinfo.ipi_count;
		req->oldidx = 2 * (sizeof xig)
			+ (n + n/8) * sizeof(struct xinpcb);
		return 0;
	}

	if (req->newptr != 0)
		return EPERM;

	/*
	 * OK, now we're committed to doing something.
	 */
	s = splnet();
	gencnt = udbinfo.ipi_gencnt;
	n = udbinfo.ipi_count;
	splx(s);

	xig.xig_len = sizeof xig;
	xig.xig_count = n;
	xig.xig_gen = gencnt;
	xig.xig_sogen = so_gencnt;
	error = SYSCTL_OUT(req, &xig, sizeof xig);
	if (error)
		return error;
    /*
     * We are done if there is no pcb
     */
    if (n == 0)  
        return 0; 

	inp_list = _MALLOC(n * sizeof *inp_list, M_TEMP, M_WAITOK);
	if (inp_list == 0) {
		return ENOMEM;
	}
	
	for (inp = LIST_FIRST(udbinfo.listhead), i = 0; inp && i < n;
	     inp = LIST_NEXT(inp, inp_list)) {
		if (inp->inp_gencnt <= gencnt)
			inp_list[i++] = inp;
	}
	splx(s);
	n = i;

	error = 0;
	for (i = 0; i < n; i++) {
		inp = inp_list[i];
		if (inp->inp_gencnt <= gencnt) {
			struct xinpcb xi;
			xi.xi_len = sizeof xi;
			/* XXX should avoid extra copy */
			bcopy(inp, &xi.xi_inp, sizeof *inp);
			if (inp->inp_socket)
				sotoxsocket(inp->inp_socket, &xi.xi_socket);
			error = SYSCTL_OUT(req, &xi, sizeof xi);
		}
	}
	if (!error) {
		/*
		 * Give the user an updated idea of our state.
		 * If the generation differs from what we told
		 * her before, she knows that something happened
		 * while we were processing this request, and it
		 * might be necessary to retry.
		 */
		s = splnet();
		xig.xig_gen = udbinfo.ipi_gencnt;
		xig.xig_sogen = so_gencnt;
		xig.xig_count = udbinfo.ipi_count;
		splx(s);
		error = SYSCTL_OUT(req, &xig, sizeof xig);
	}
	FREE(inp_list, M_TEMP);
	return error;
}

SYSCTL_PROC(_net_inet_udp, UDPCTL_PCBLIST, pcblist, CTLFLAG_RD, 0, 0,
	    udp_pcblist, "S,xinpcb", "List of active UDP sockets");



static int
udp_output(inp, m, addr, control, p)
	register struct inpcb *inp;
	struct mbuf *m;
	struct sockaddr *addr;
	struct mbuf *control;
	struct proc *p;
{
	register struct udpiphdr *ui;
	register int len = m->m_pkthdr.len;
	struct in_addr laddr;
	int s = 0, error = 0;

	KERNEL_DEBUG(DBG_FNC_UDP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);

	if (control)
		m_freem(control);		/* XXX */

	KERNEL_DEBUG(DBG_LAYER_OUT_BEG, inp->inp_fport, inp->inp_lport,
		     inp->inp_laddr.s_addr, inp->inp_faddr.s_addr,
		     (htons((u_short)len + sizeof (struct udphdr))));

	if (len + sizeof(struct udpiphdr) > IP_MAXPACKET) {
		error = EMSGSIZE;
		goto release;
	}

	if (addr) {
		laddr = inp->inp_laddr;
		if (inp->inp_faddr.s_addr != INADDR_ANY) {
			error = EISCONN;
			goto release;
		}
		/*
		 * Must block input while temporarily connected.
		 */
		s = splnet();
		error = in_pcbconnect(inp, addr, p);
		if (error) {
			splx(s);
			goto release;
		}
	} else {
		if (inp->inp_faddr.s_addr == INADDR_ANY) {
			error = ENOTCONN;
			goto release;
		}
	}
	/*
	 * Calculate data length and get a mbuf
	 * for UDP and IP headers.
	 */
	M_PREPEND(m, sizeof(struct udpiphdr), M_DONTWAIT);
	if (m == 0) {
		error = ENOBUFS;
		if (addr)
			splx(s);
		goto release;
	}

	/*
	 * Fill in mbuf with extended UDP header
	 * and addresses and length put into network format.
	 */
	ui = mtod(m, struct udpiphdr *);
	bzero(ui->ui_x1, sizeof(ui->ui_x1));	/* XXX still needed? */
	ui->ui_pr = IPPROTO_UDP;
	ui->ui_src = inp->inp_laddr;
	ui->ui_dst = inp->inp_faddr;
	ui->ui_sport = inp->inp_lport;
	ui->ui_dport = inp->inp_fport;
	ui->ui_ulen = htons((u_short)len + sizeof(struct udphdr));

	/*
	 * Set up checksum and output datagram.
	 */
	if (udpcksum) {
        	ui->ui_sum = in_pseudo(ui->ui_src.s_addr, ui->ui_dst.s_addr,
		    htons((u_short)len + sizeof(struct udphdr) + IPPROTO_UDP));
		m->m_pkthdr.csum_flags = CSUM_UDP;
		m->m_pkthdr.csum_data = offsetof(struct udphdr, uh_sum);
	} else {
		ui->ui_sum = 0;
	}
	((struct ip *)ui)->ip_len = sizeof (struct udpiphdr) + len;
	((struct ip *)ui)->ip_ttl = inp->inp_ip_ttl;	/* XXX */
	((struct ip *)ui)->ip_tos = inp->inp_ip_tos;	/* XXX */
	udpstat.udps_opackets++;

	KERNEL_DEBUG(DBG_LAYER_OUT_END, ui->ui_dport, ui->ui_sport,
		     ui->ui_src.s_addr, ui->ui_dst.s_addr, ui->ui_ulen);

#if IPSEC
	if (ipsec_bypass == 0 && ipsec_setsocket(m, inp->inp_socket) != 0) {
		error = ENOBUFS;
		goto release;
	}
#endif /*IPSEC*/
	error = ip_output(m, inp->inp_options, &inp->inp_route,
	    (inp->inp_socket->so_options & (SO_DONTROUTE | SO_BROADCAST)),
	    inp->inp_moptions);

	if (addr) {
		in_pcbdisconnect(inp);
		inp->inp_laddr = laddr;	/* XXX rehash? */
		splx(s);
	}
	KERNEL_DEBUG(DBG_FNC_UDP_OUTPUT | DBG_FUNC_END, error, 0,0,0,0);
	return (error);

release:
	m_freem(m);
	KERNEL_DEBUG(DBG_FNC_UDP_OUTPUT | DBG_FUNC_END, error, 0,0,0,0);
	return (error);
}

u_long	udp_sendspace = 9216;		/* really max datagram size */
					/* 40 1K datagrams */
SYSCTL_INT(_net_inet_udp, UDPCTL_MAXDGRAM, maxdgram, CTLFLAG_RW,
    &udp_sendspace, 0, "Maximum outgoing UDP datagram size");

u_long	udp_recvspace = 40 * (1024 +
#if INET6
				      sizeof(struct sockaddr_in6)
#else
				      sizeof(struct sockaddr_in)
#endif
				      );
SYSCTL_INT(_net_inet_udp, UDPCTL_RECVSPACE, recvspace, CTLFLAG_RW,
    &udp_recvspace, 0, "Maximum incoming UDP datagram size");

static int
udp_abort(struct socket *so)
{
	struct inpcb *inp;
	int s;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;	/* ??? possible? panic instead? */
	soisdisconnected(so);
	s = splnet();
	in_pcbdetach(inp);
	splx(s);
	return 0;
}

static int
udp_attach(struct socket *so, int proto, struct proc *p)
{
	struct inpcb *inp;
	int error; long s;

	inp = sotoinpcb(so);
	if (inp != 0)
		return EINVAL;

	error = soreserve(so, udp_sendspace, udp_recvspace);
	if (error)
		return error;
	s = splnet();
	error = in_pcballoc(so, &udbinfo, p);
	splx(s);
	if (error)
		return error;
	inp = (struct inpcb *)so->so_pcb;
	inp->inp_vflag |= INP_IPV4;
	inp->inp_ip_ttl = ip_defttl;
	return 0;
}

static int
udp_bind(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	struct inpcb *inp;
	int s, error;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;
	s = splnet();
	error = in_pcbbind(inp, nam, p);
	splx(s);
	return error;
}

static int
udp_connect(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	struct inpcb *inp;
	int s, error;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;
	if (inp->inp_faddr.s_addr != INADDR_ANY)
		return EISCONN;
	s = splnet();
	error = in_pcbconnect(inp, nam, p);
	splx(s);
	if (error == 0)
		soisconnected(so);
	return error;
}

static int
udp_detach(struct socket *so)
{
	struct inpcb *inp;
	int s;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;
	s = splnet();
	in_pcbdetach(inp);
	splx(s);
	return 0;
}

static int
udp_disconnect(struct socket *so)
{
	struct inpcb *inp;
	int s;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;
	if (inp->inp_faddr.s_addr == INADDR_ANY)
		return ENOTCONN;

	s = splnet();
	in_pcbdisconnect(inp);
	inp->inp_laddr.s_addr = INADDR_ANY;
	splx(s);
	so->so_state &= ~SS_ISCONNECTED;		/* XXX */
	return 0;
}

static int
udp_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
	    struct mbuf *control, struct proc *p)
{
	struct inpcb *inp;

	inp = sotoinpcb(so);
	if (inp == 0) {
		m_freem(m);
		return EINVAL;
	}
	return udp_output(inp, m, addr, control, p);
}

int
udp_shutdown(struct socket *so)
{
	struct inpcb *inp;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;
	socantsendmore(so);
	return 0;
}

struct pr_usrreqs udp_usrreqs = {
	udp_abort, pru_accept_notsupp, udp_attach, udp_bind, udp_connect, 
	pru_connect2_notsupp, in_control, udp_detach, udp_disconnect, 
	pru_listen_notsupp, in_setpeeraddr, pru_rcvd_notsupp, 
	pru_rcvoob_notsupp, udp_send, pru_sense_null, udp_shutdown,
	in_setsockaddr, sosend, soreceive, sopoll
};