udp6_usrreq.c   [plain text]

/*
 * Copyright (c) 2000-2012 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * 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. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * 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_OSREFERENCE_LICENSE_HEADER_END@
 */

/*	$FreeBSD: src/sys/netinet6/udp6_usrreq.c,v 1.6.2.6 2001/07/29 19:32:40 ume Exp $	*/
/*	$KAME: udp6_usrreq.c,v 1.27 2001/05/21 05:45:10 jinmei Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
 */

/*
 * Copyright (c) 1982, 1986, 1989, 1993
 *	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_var.h	8.1 (Berkeley) 6/10/93
 */

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/syslog.h>
#include <sys/proc.h>
#include <sys/kauth.h>

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

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_pcb.h>
#include <netinet/icmp6.h>
#include <netinet6/udp6_var.h>
#include <netinet6/ip6protosw.h>

#if IPSEC
#include <netinet6/ipsec.h>
#include <netinet6/ipsec6.h>
extern int ipsec_bypass;
#endif /*IPSEC*/

/*
 * UDP protocol inplementation.
 * Per RFC 768, August, 1980.
 */

extern	struct protosw inetsw[];
static	int udp6_detach(struct socket *so);
static void udp6_append(struct inpcb *, struct ip6_hdr *,
    struct sockaddr_in6 *, struct mbuf *, int);

extern  void    ipfwsyslog( int level, const char *format,...);
extern int fw_verbose;

#if IPFIREWALL
#define log_in_vain_log( a ) {            \
        if ( (log_in_vain == 3 ) && (fw_verbose == 2)) {        /* Apple logging, log to ipfw.log */ \
                ipfwsyslog a ;  \
        }                       \
        else log a ;            \
}
#else
#define log_in_vain_log( a ) { log a; }
#endif

/*
 * subroutine of udp6_input(), mainly for source code readability.
 */
static void
udp6_append(struct inpcb *last, __unused struct ip6_hdr *ip6,
    struct sockaddr_in6 *udp_in6, struct mbuf *n, int off)
{
	struct  mbuf *opts = NULL;
	int ret = 0;
#if CONFIG_MACF_NET
	if (mac_inpcb_check_deliver(last, n, AF_INET6, SOCK_DGRAM) != 0) {
		m_freem(n);
		return;
	}
#endif
	if ((last->in6p_flags & IN6P_CONTROLOPTS) != 0 ||
	    (last->in6p_socket->so_options & SO_TIMESTAMP) != 0 ||
	    (last->in6p_socket->so_options & SO_TIMESTAMP_MONOTONIC) != 0) {
		ret = ip6_savecontrol(last, n, &opts);
		if (ret != 0) {
			m_freem(n);
			m_freem(opts);
			return;
		}
	}
	m_adj(n, off);
	if (nstat_collect) {
		locked_add_64(&last->inp_stat->rxpackets, 1);
		locked_add_64(&last->inp_stat->rxbytes, n->m_pkthdr.len);
	}
	so_recv_data_stat(last->in6p_socket, n, 0);
	if (sbappendaddr(&last->in6p_socket->so_rcv,
	    (struct sockaddr *)udp_in6, n, opts, NULL) == 0)
		udpstat.udps_fullsock++;
	else
		sorwakeup(last->in6p_socket);
}

int
udp6_input(
	struct mbuf **mp,
	int *offp,
	int proto)
{
#pragma unused(proto)
	struct mbuf *m = *mp;
	struct ifnet *ifp;
	register struct ip6_hdr *ip6;
	register struct udphdr *uh;
	register struct inpcb *in6p;
	struct  mbuf *opts = NULL;
	int off = *offp;
	int plen, ulen, ret = 0;
	struct sockaddr_in6 udp_in6;
	struct inpcbinfo *pcbinfo = &udbinfo;
	struct sockaddr_in6 fromsa;

	IP6_EXTHDR_CHECK(m, off, sizeof(struct udphdr), return IPPROTO_DONE);

	/* Expect 32-bit aligned data pointer on strict-align platforms */
	MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);

	ifp = m->m_pkthdr.rcvif;
	ip6 = mtod(m, struct ip6_hdr *);

	udpstat.udps_ipackets++;

	plen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
	uh = (struct udphdr *)(void *)((caddr_t)ip6 + off);
	ulen = ntohs((u_short)uh->uh_ulen);

	if (plen != ulen) {
		udpstat.udps_badlen++;

		if (ifp->if_udp_stat != NULL)
			atomic_add_64(&ifp->if_udp_stat->badlength, 1);

		goto bad;
	}

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

		if (ifp->if_udp_stat != NULL)
			atomic_add_64(&ifp->if_udp_stat->port0, 1);

		goto bad;
	}

	/*
	 * Checksum extended UDP header and data.
	 */
	if (uh->uh_sum) {
		if ((apple_hwcksum_rx != 0) && (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)) {
			uh->uh_sum = m->m_pkthdr.csum_data;
			uh->uh_sum ^= 0xffff;
		}
		else {
			if (in6_cksum(m, IPPROTO_UDP, off, ulen) != 0) {
				udpstat.udps_badsum++;

				if (ifp->if_udp_stat != NULL)
					atomic_add_64(&ifp->if_udp_stat->badchksum, 1);

				goto bad;
			}
		}
	}
#ifndef __APPLE__
	else
		udpstat.udps_nosum++;
#endif

	/*
	 * Construct sockaddr format source address.
	 */
	init_sin6(&fromsa, m);
	fromsa.sin6_port = uh->uh_sport;


	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
		int reuse_sock = 0, mcast_delivered = 0;
		struct ip6_moptions *imo;
		struct mbuf *n = NULL;

		/*
		 * Deliver a multicast 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 multicasts 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?)
		 */

		/*
		 * In a case that laddr should be set to the link-local
		 * address (this happens in RIPng), the multicast address
		 * specified in the received packet does not match with
		 * laddr. To cure this situation, the matching is relaxed
		 * if the receiving interface is the same as one specified
		 * in the socket and if the destination multicast address
		 * matches one of the multicast groups specified in the socket.
		 */

		/*
		 * Construct sockaddr format source address.
		 */
		init_sin6(&udp_in6, m); /* general init */
		udp_in6.sin6_port = uh->uh_sport;
		/*
		 * KAME note: usually we drop udphdr from mbuf here.
		 * We need udphdr for IPsec processing so we do that later.
		 */

		/*
		 * Locate pcb(s) for datagram.
		 * (Algorithm copied from raw_intr().)
		 */
		lck_rw_lock_shared(pcbinfo->mtx);

		LIST_FOREACH(in6p, &udb, inp_list) {

			if ((in6p->inp_vflag & INP_IPV6) == 0)
				continue;

			if (ip6_restrictrecvif && ifp != NULL &&
			    (ifp->if_eflags & IFEF_RESTRICTED_RECV) &&
			    !(in6p->in6p_flags & IN6P_RECV_ANYIF))
				continue;

			if (in_pcb_checkstate(in6p, WNT_ACQUIRE, 0) == WNT_STOPUSING)
				continue;

			udp_lock(in6p->in6p_socket, 1, 0);

			if (in_pcb_checkstate(in6p, WNT_RELEASE, 1) == WNT_STOPUSING) {
				udp_unlock(in6p->in6p_socket, 1, 0);
				continue;
			}
			if (in6p->in6p_lport != uh->uh_dport) {
				udp_unlock(in6p->in6p_socket, 1, 0);
				continue;
			}

			/*
			 * Handle socket delivery policy for any-source
			 * and source-specific multicast. [RFC3678]
			 */
			imo = in6p->in6p_moptions;
			if (imo && IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
				struct sockaddr_in6	 mcaddr;
				int			 blocked;

				IM6O_LOCK(imo);
				bzero(&mcaddr, sizeof(struct sockaddr_in6));
				mcaddr.sin6_len = sizeof(struct sockaddr_in6);
				mcaddr.sin6_family = AF_INET6;
				mcaddr.sin6_addr = ip6->ip6_dst;

				blocked = im6o_mc_filter(imo, ifp,
					(struct sockaddr *)&mcaddr,
					(struct sockaddr *)&fromsa);
				IM6O_UNLOCK(imo);
				if (blocked != MCAST_PASS) {
					udp_unlock(in6p->in6p_socket, 1, 0);
					continue;
				}
			}
			if (!IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
				if (!IN6_ARE_ADDR_EQUAL(&in6p->in6p_faddr,
							&ip6->ip6_src) ||
				   in6p->in6p_fport != uh->uh_sport) {
					udp_unlock(in6p->in6p_socket, 1, 0);
					continue;
				}
			}

			reuse_sock = in6p->inp_socket->so_options &
			    (SO_REUSEPORT | SO_REUSEADDR);

			{
#if IPSEC
				int skipit = 0;
				/* Check AH/ESP integrity. */
				if (ipsec_bypass == 0) {
					if (ipsec6_in_reject_so(m, in6p->inp_socket)) {
						IPSEC_STAT_INCREMENT(ipsec6stat.in_polvio);
						/* do not inject data to pcb */
						skipit = 1;
					}
				}
				if (skipit == 0)
#endif /*IPSEC*/
				{
					/*
					 * KAME NOTE: do not
					 * m_copy(m, offset, ...) below.
					 * sbappendaddr() expects M_PKTHDR,
					 * and m_copy() will copy M_PKTHDR
					 * only if offset is 0.
					 */
					if (reuse_sock)
						n = m_copy(m, 0, M_COPYALL);
					udp6_append(in6p, ip6, &udp_in6, m,
					    off + sizeof (struct udphdr));
					mcast_delivered++;
				}
				udp_unlock(in6p->in6p_socket, 1, 0);
			}
			/*
			 * 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 (reuse_sock == 0 || ((m = n) == NULL))
				break;

			/*
			 * Expect 32-bit aligned data pointer on strict-align
			 * platforms.
			 */
			MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);

			/*
			 * Recompute IP and UDP header pointers for new mbuf
			 */
			ip6 = mtod(m, struct ip6_hdr *);
			uh = (struct udphdr *)(void *)((caddr_t)ip6 + off);
		}
		lck_rw_done(pcbinfo->mtx);

		if (mcast_delivered == 0) {
			/*
			 * No matching pcb found; discard datagram.
			 * (No need to send an ICMP Port Unreachable
			 * for a broadcast or multicast datgram.)
			 */
			udpstat.udps_noport++;
#ifndef __APPLE__
			udpstat.udps_noportmcast++;
#endif
			if (ifp->if_udp_stat != NULL)
				atomic_add_64(&ifp->if_udp_stat->port_unreach, 1);

			goto bad;
		}

		if (reuse_sock != 0)	/* free the extra copy of mbuf */
			m_freem(m);
		return IPPROTO_DONE;
	}
	/*
	 * Locate pcb for datagram.
	 */
	in6p = in6_pcblookup_hash(&udbinfo, &ip6->ip6_src, uh->uh_sport,
				  &ip6->ip6_dst, uh->uh_dport, 1,
				  m->m_pkthdr.rcvif);
	if (in6p == NULL) {

		if (ifp->if_udp_stat != NULL)
			atomic_add_64(&ifp->if_udp_stat->port_unreach, 1);

		if (log_in_vain) {
			char buf[INET6_ADDRSTRLEN];

			strlcpy(buf, ip6_sprintf(&ip6->ip6_dst), sizeof(buf));
			if (log_in_vain != 3)
				log(LOG_INFO,
				    "Connection attempt to UDP %s:%d from %s:%d\n",
				    buf, ntohs(uh->uh_dport),
				    ip6_sprintf(&ip6->ip6_src), ntohs(uh->uh_sport));
			else if (!(m->m_flags & (M_BCAST | M_MCAST)) &&
					 !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6->ip6_src))
				log_in_vain_log((LOG_INFO,
				    "Connection attempt to UDP %s:%d from %s:%d\n",
				    buf, ntohs(uh->uh_dport),
				    ip6_sprintf(&ip6->ip6_src), ntohs(uh->uh_sport)));
		}
		udpstat.udps_noport++;
		if (m->m_flags & M_MCAST) {
			printf("UDP6: M_MCAST is set in a unicast packet.\n");
#ifndef __APPLE__
			udpstat.udps_noportmcast++;
#endif
			if (ifp->if_udp_stat != NULL)
				atomic_add_64(&ifp->if_udp_stat->badmcast, 1);

			goto bad;
		}
		icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_NOPORT, 0);
		return IPPROTO_DONE;
	}
#if IPSEC
	/*
	 * Check AH/ESP integrity.
	 */
	if (ipsec_bypass == 0) {
		if (ipsec6_in_reject_so(m, in6p->in6p_socket)) {
			IPSEC_STAT_INCREMENT(ipsec6stat.in_polvio);
			in_pcb_checkstate(in6p, WNT_RELEASE, 0);

			if (ifp->if_udp_stat != NULL)
				atomic_add_64(&ifp->if_udp_stat->badipsec, 1);

			goto bad;
		}
	}
#endif /*IPSEC*/

	/*
	 * Construct sockaddr format source address.
	 * Stuff source address and datagram in user buffer.
	 */
	udp_lock(in6p->in6p_socket, 1, 0);

	if (in_pcb_checkstate(in6p, WNT_RELEASE, 1) == WNT_STOPUSING) {
		udp_unlock(in6p->in6p_socket, 1, 0);

		if (ifp->if_udp_stat != NULL)
			atomic_add_64(&ifp->if_udp_stat->cleanup, 1);

		goto bad;
	}

	init_sin6(&udp_in6, m); /* general init */
	udp_in6.sin6_port = uh->uh_sport;
	if ((in6p->in6p_flags & IN6P_CONTROLOPTS) != 0 ||
		(in6p->in6p_socket->so_options & SO_TIMESTAMP) != 0 ||
		(in6p->in6p_socket->so_options & SO_TIMESTAMP_MONOTONIC) != 0) {
		ret = ip6_savecontrol(in6p, m, &opts);
		if (ret != 0) {
			udp_unlock(in6p->in6p_socket, 1, 0);
			goto bad;
		}
	}
	m_adj(m, off + sizeof(struct udphdr));
	if (nstat_collect) {
		locked_add_64(&in6p->inp_stat->rxpackets, 1);
		locked_add_64(&in6p->inp_stat->rxbytes, m->m_pkthdr.len);
	}
	so_recv_data_stat(in6p->in6p_socket, m, 0);
	if (sbappendaddr(&in6p->in6p_socket->so_rcv,
			(struct sockaddr *)&udp_in6,
			m, opts, NULL) == 0) {
		m = NULL;
		opts = NULL;
		udpstat.udps_fullsock++;
		udp_unlock(in6p->in6p_socket, 1, 0);
		goto bad;
	}
	sorwakeup(in6p->in6p_socket);
	udp_unlock(in6p->in6p_socket, 1, 0);
	return IPPROTO_DONE;
bad:
	if (m)
		m_freem(m);
	if (opts)
		m_freem(opts);
	return IPPROTO_DONE;
}

void
udp6_ctlinput(
	int cmd,
	struct sockaddr *sa,
	void *d)
{
	struct udphdr uh;
	struct ip6_hdr *ip6;
	struct mbuf *m;
	int off = 0;
	struct ip6ctlparam *ip6cp = NULL;
	const struct sockaddr_in6 *sa6_src = NULL;
	void (*notify)(struct inpcb *, int) = udp_notify;
	struct udp_portonly {
		u_int16_t uh_sport;
		u_int16_t uh_dport;
	} *uhp;

	if (sa->sa_family != AF_INET6 ||
	    sa->sa_len != sizeof(struct sockaddr_in6))
		return;

	if ((unsigned)cmd >= PRC_NCMDS)
		return;
	if (PRC_IS_REDIRECT(cmd))
		notify = in6_rtchange, d = NULL;
	else if (cmd == PRC_HOSTDEAD)
		d = NULL;
	else if (inet6ctlerrmap[cmd] == 0)
		return;

	/* if the parameter is from icmp6, decode it. */
	if (d != NULL) {
		ip6cp = (struct ip6ctlparam *)d;
		m = ip6cp->ip6c_m;
		ip6 = ip6cp->ip6c_ip6;
		off = ip6cp->ip6c_off;
		sa6_src = ip6cp->ip6c_src;
	} else {
		m = NULL;
		ip6 = NULL;
		sa6_src = &sa6_any;
	}

	if (ip6) {
		/*
		 * XXX: We assume that when IPV6 is non NULL,
		 * M and OFF are valid.
		 */

		/* check if we can safely examine src and dst ports */
		if (m->m_pkthdr.len < off + sizeof(*uhp))
			return;

		bzero(&uh, sizeof(uh));
		m_copydata(m, off, sizeof(*uhp), (caddr_t)&uh);

		(void) in6_pcbnotify(&udbinfo, sa, uh.uh_dport,
					(struct sockaddr*)ip6cp->ip6c_src,
					uh.uh_sport, cmd, NULL, notify);
	} else
		(void) in6_pcbnotify(&udbinfo, sa, 0, (struct sockaddr *)&sa6_src,
				     0, cmd, NULL, notify);
}

#ifndef __APPLE__
static int
udp6_getcred SYSCTL_HANDLER_ARGS
{
	struct sockaddr_in6 addrs[2];
	struct inpcb *inp;
	int error, s;

	error = proc_suser(req->p);
	if (error)
		return (error);

	if (req->newlen != sizeof(addrs))
		return (EINVAL);
	if (req->oldlen != sizeof(*(kauth_cred_t)0))
		return (EINVAL);
	error = SYSCTL_IN(req, addrs, sizeof(addrs));
	if (error)
		return (error);
	s = splnet();
	inp = in6_pcblookup_hash(&udbinfo, &addrs[1].sin6_addr,
				 addrs[1].sin6_port,
				 &addrs[0].sin6_addr, addrs[0].sin6_port,
				 1, NULL);
	if (!inp || !inp->inp_socket || !inp->inp_socket->so_cred) {
		error = ENOENT;
		goto out;
	}
	/*
	 * XXX This should not be copying out a credential!!!!  This
	 * XXX is an opaque type, and is not intended to be introspected,
	 * XXX and the size of this structure *WILL* change as planned MACF
	 * XXX and kauth changes go forward.
	 */
	error = SYSCTL_OUT(req, inp->inp_socket->so_cred->pc_ucred,
			   sizeof(*(kauth_cred_t)0));

out:
	splx(s);
	return (error);
}

SYSCTL_PROC(_net_inet6_udp6, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW,
	    0, 0,
	    udp6_getcred, "S,ucred", "Get the ucred of a UDP6 connection");
#endif

static int
udp6_abort(struct socket *so)
{
	struct inpcb *inp;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;	/* ??? possible? panic instead? */
	soisdisconnected(so);
	in6_pcbdetach(inp);
	return 0;
}

static int
udp6_attach(struct socket *so, __unused int proto, struct proc *p)
{
	struct inpcb *inp;
	int error;

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

	error = in_pcballoc(so, &udbinfo, p);
	if (error)
		return error;

	if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
		error = soreserve(so, udp_sendspace, udp_recvspace);
		if (error)
			return error;
	}
	inp = (struct inpcb *)so->so_pcb;
	inp->inp_vflag |= INP_IPV6;
	if (ip6_mapped_addr_on)
		inp->inp_vflag |= INP_IPV4;
	inp->in6p_hops = -1;	/* use kernel default */
	inp->in6p_cksum = -1;	/* just to be sure */
	/*
	 * XXX: ugly!!
	 * IPv4 TTL initialization is necessary for an IPv6 socket as well,
	 * because the socket may be bound to an IPv6 wildcard address,
	 * which may match an IPv4-mapped IPv6 address.
	 */
	inp->inp_ip_ttl = ip_defttl;
	if (nstat_collect)
		nstat_udp_new_pcb(inp);
	return 0;
}

static int
udp6_bind(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	struct inpcb *inp;
	int error;

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

	inp->inp_vflag &= ~INP_IPV4;
	inp->inp_vflag |= INP_IPV6;
	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
		struct sockaddr_in6 *sin6_p;

		sin6_p = (struct sockaddr_in6 *)(void *)nam;

		if (IN6_IS_ADDR_UNSPECIFIED(&sin6_p->sin6_addr))
			inp->inp_vflag |= INP_IPV4;
		else if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
			struct sockaddr_in sin;

			in6_sin6_2_sin(&sin, sin6_p);
			inp->inp_vflag |= INP_IPV4;
			inp->inp_vflag &= ~INP_IPV6;
			error = in_pcbbind(inp, (struct sockaddr *)&sin, p);
			return error;
		}
	}

	error = in6_pcbbind(inp, nam, p);
	return error;
}

static int
udp6_connect(struct socket *so, struct sockaddr *nam, struct proc *p)
{
	struct inpcb *inp;
	int error;

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

	if ((inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
		struct sockaddr_in6 *sin6_p;

		sin6_p = (struct sockaddr_in6 *)(void *)nam;
		if (IN6_IS_ADDR_V4MAPPED(&sin6_p->sin6_addr)) {
			struct sockaddr_in sin;

			if (inp->inp_faddr.s_addr != INADDR_ANY)
				return EISCONN;
			in6_sin6_2_sin(&sin, sin6_p);
			error = in_pcbconnect(inp, (struct sockaddr *)&sin, p, NULL);
			if (error == 0) {
				inp->inp_vflag |= INP_IPV4;
				inp->inp_vflag &= ~INP_IPV6;
				soisconnected(so);
			}
			return error;
		}
	}

	if (!IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr))
		return EISCONN;
	error = in6_pcbconnect(inp, nam, p);
	if (error == 0) {
		if (ip6_mapped_addr_on || (inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) { /* should be non mapped addr */
			inp->inp_vflag &= ~INP_IPV4;
			inp->inp_vflag |= INP_IPV6;
		}
		soisconnected(so);
		if (inp->inp_flowhash == 0)
			inp->inp_flowhash = inp_calc_flowhash(inp);
	}
	return error;
}

static int
udp6_detach(struct socket *so)
{
	struct inpcb *inp;

	inp = sotoinpcb(so);
	if (inp == 0)
		return EINVAL;
	in6_pcbdetach(inp);
	return 0;
}

static int
udp6_disconnect(struct socket *so)
{
	struct inpcb *inp;

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

	if (inp->inp_vflag & INP_IPV4) {
		struct pr_usrreqs *pru;

		pru = ip_protox[IPPROTO_UDP]->pr_usrreqs;
		return ((*pru->pru_disconnect)(so));
	}

	if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr))
		return ENOTCONN;

	in6_pcbdisconnect(inp);

	/* reset flow-controlled state, just in case */
	inp_reset_fc_state(inp);

	inp->in6p_laddr = in6addr_any;
	inp->in6p_last_outifp = NULL;
	so->so_state &= ~SS_ISCONNECTED;		/* XXX */
	return 0;
}

static int
udp6_send(struct socket *so, int flags, struct mbuf *m, struct sockaddr *addr,
	  struct mbuf *control, struct proc *p)
{
	struct inpcb *inp;
	int error = 0;

	inp = sotoinpcb(so);
	if (inp == 0) {
		error = EINVAL;
		goto bad;
	}

	if (addr) {
		if (addr->sa_len != sizeof(struct sockaddr_in6)) { 
			error = EINVAL;
			goto bad;
		}
		if (addr->sa_family != AF_INET6) {
			error = EAFNOSUPPORT;
			goto bad;
		}
	}

	if (ip6_mapped_addr_on || (inp->inp_flags & IN6P_IPV6_V6ONLY) == 0) {
		int hasv4addr;
		struct sockaddr_in6 *sin6 = 0;

		if (addr == 0)
			hasv4addr = (inp->inp_vflag & INP_IPV4);
		else {
			sin6 = (struct sockaddr_in6 *)(void *)addr;
			hasv4addr = IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)
				? 1 : 0;
		}
		if (hasv4addr) {
			struct pr_usrreqs *pru;

			if (sin6)
				in6_sin6_2_sin_in_sock(addr);
			pru = ip_protox[IPPROTO_UDP]->pr_usrreqs;
			error = ((*pru->pru_send)(so, flags, m, addr, control,
						  p));
			/* addr will just be freed in sendit(). */
			return error;
		}
	}

	return udp6_output(inp, m, addr, control, p);

  bad:
	m_freem(m);
	return(error);
}

struct pr_usrreqs udp6_usrreqs = {
	udp6_abort, pru_accept_notsupp, udp6_attach, udp6_bind, udp6_connect,
	pru_connect2_notsupp, in6_control, udp6_detach, udp6_disconnect,
	pru_listen_notsupp, in6_mapped_peeraddr, pru_rcvd_notsupp,
	pru_rcvoob_notsupp, udp6_send, pru_sense_null, udp_shutdown,
	in6_mapped_sockaddr, sosend, soreceive, pru_sopoll_notsupp
};