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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_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. 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/if_types.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;
extern lck_mtx_t *sadb_mutex;
#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)

/*
 * 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;
extern  int     esp_udp_encap_port;
extern  u_long  route_generation;

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

#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 ;            \
}

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)");
SYSCTL_INT(_net_inet_udp, OID_AUTO, pcbcount, CTLFLAG_RD, 
    &udbinfo.ipi_count, 0, "Number of active PCBs");

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

static int udp_detach(struct socket *so);
static  int udp_output(struct inpcb *, struct mbuf *, struct sockaddr *,
                            struct mbuf *, struct proc *);
extern int ChkAddressOK( __uint32_t dstaddr, __uint32_t srcaddr );

void
udp_init()
{
        vm_size_t                       str_size;
        struct inpcbinfo        *pcbinfo;
        

        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");

        pcbinfo = &udbinfo;
        /*
         * allocate lock group attribute and group for udp pcb mutexes
         */
        pcbinfo->mtx_grp_attr = lck_grp_attr_alloc_init();
        lck_grp_attr_setdefault(pcbinfo->mtx_grp_attr);

        pcbinfo->mtx_grp = lck_grp_alloc_init("udppcb", pcbinfo->mtx_grp_attr);
                
        pcbinfo->mtx_attr = lck_attr_alloc_init();
        lck_attr_setdefault(pcbinfo->mtx_attr);

        if ((pcbinfo->mtx = lck_rw_alloc_init(pcbinfo->mtx_grp, pcbinfo->mtx_attr)) == NULL)
                return; /* pretty much dead if this fails... */

        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;
        struct inpcbinfo *pcbinfo = &udbinfo;

        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 {
                        char b[9];
doudpcksum:
                        *(uint32_t*)&b[0] = *(uint32_t*)&((struct ipovly *)ip)->ih_x1[0];
                        *(uint32_t*)&b[4] = *(uint32_t*)&((struct ipovly *)ip)->ih_x1[4];
                        *(uint8_t*)&b[8] = *(uint8_t*)&((struct ipovly *)ip)->ih_x1[8];
                        
                        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));
                        
                        *(uint32_t*)&((struct ipovly *)ip)->ih_x1[0] = *(uint32_t*)&b[0];
                        *(uint32_t*)&((struct ipovly *)ip)->ih_x1[4] = *(uint32_t*)&b[4];
                        *(uint8_t*)&((struct ipovly *)ip)->ih_x1[8] = *(uint8_t*)&b[8];
                }
                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;
                lck_rw_lock_shared(pcbinfo->mtx);
                /*
                 * 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 (inp->inp_socket == NULL) 
                                continue;
                        if (inp != sotoinpcb(inp->inp_socket))
                                panic("udp_input: bad so back ptr inp=%x\n", inp);
#if INET6
                        if ((inp->inp_vflag & INP_IPV4) == 0)
                                continue;
#endif
                        if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) {
                                continue;
                        }
                        
                        udp_lock(inp->inp_socket, 1, 0);        

                        if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
                                udp_unlock(inp->inp_socket, 1, 0);
                                continue;
                        }

                        if (inp->inp_lport != uh->uh_dport) {
                                udp_unlock(inp->inp_socket, 1, 0);
                                continue;
                        }
                        if (inp->inp_laddr.s_addr != INADDR_ANY) {
                                if (inp->inp_laddr.s_addr !=
                                    ip->ip_dst.s_addr) {
                                        udp_unlock(inp->inp_socket, 1, 0);
                                        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) {
                                        udp_unlock(inp->inp_socket, 1, 0);
                                        continue;
                                }
                        }

                        if (last != NULL) {
                                struct mbuf *n;
#if IPSEC
                                int skipit = 0;
                                /* check AH/ESP integrity. */
                                if (ipsec_bypass == 0) {
                                        lck_mtx_lock(sadb_mutex);
                                        if (ipsec4_in_reject_so(m, last->inp_socket)) {
                                                ipsecstat.in_polvio++;
                                                /* do not inject data to pcb */
                                                skipit = 1;
                                        }
                                        lck_mtx_unlock(sadb_mutex);
                                }
                                if (skipit == 0)
#endif /*IPSEC*/
                                if ((n = m_copy(m, 0, M_COPYALL)) != NULL) {
                                        udp_append(last, ip, n,
                                                   iphlen +
                                                   sizeof(struct udphdr));
                                }
                                udp_unlock(last->inp_socket, 1, 0);
                        }
                        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;
                }
                lck_rw_done(pcbinfo->mtx);

                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) {
                        lck_mtx_lock(sadb_mutex);
                        if (ipsec4_in_reject_so(m, last->inp_socket)) {
                                ipsecstat.in_polvio++;
                                lck_mtx_unlock(sadb_mutex);
                                udp_unlock(last->inp_socket, 1, 0);
                                goto bad;
                        }
                        lck_mtx_unlock(sadb_mutex);
                }
#endif /*IPSEC*/
                udp_append(last, ip, m, iphlen + sizeof(struct udphdr));
                udp_unlock(last->inp_socket, 1, 0);
                return;
        }

#if IPSEC
        /*
         * UDP to port 4500 with a payload where the first four bytes are
         * not zero is a UDP encapsulated IPSec packet. Packets where
         * the payload is one byte and that byte is 0xFF are NAT keepalive
         * packets. Decapsulate the ESP packet and carry on with IPSec input
         * or discard the NAT keep-alive.
         */
        if (ipsec_bypass == 0 && (esp_udp_encap_port & 0xFFFF) != 0 &&
                uh->uh_dport == ntohs((u_short)esp_udp_encap_port)) {
                int     payload_len = len - sizeof(struct udphdr) > 4 ? 4 : len - sizeof(struct udphdr);
                if (m->m_len < iphlen + sizeof(struct udphdr) + payload_len) {
                        if ((m = m_pullup(m, iphlen + sizeof(struct udphdr) + payload_len)) == 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);
                }
                /* Check for NAT keepalive packet */
                if (payload_len == 1 && *(u_int8_t*)((caddr_t)uh + sizeof(struct udphdr)) == 0xFF) {
                        m_freem(m);
                        KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
                        return;
                }
                else if (payload_len == 4 && *(u_int32_t*)((caddr_t)uh + sizeof(struct udphdr)) != 0) {
                        /* UDP encapsulated IPSec packet to pass through NAT */
                        size_t stripsiz;

                        stripsiz = sizeof(struct udphdr);

                        ip = mtod(m, struct ip *);
                        ovbcopy((caddr_t)ip, (caddr_t)(((u_char *)ip) + stripsiz), iphlen);
                        m->m_data += stripsiz;
                        m->m_len -= stripsiz;
                        m->m_pkthdr.len -= stripsiz;
                        ip = mtod(m, struct ip *);
                        ip->ip_len = ip->ip_len - stripsiz;
                        ip->ip_p = IPPROTO_ESP;

                        KERNEL_DEBUG(DBG_FNC_UDP_INPUT | DBG_FUNC_END, 0,0,0,0,0);
                        esp4_input(m, iphlen);
                        return;
                }
        }
#endif

        /*
         * 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[MAX_IPv4_STR_LEN];
                        char buf2[MAX_IPv4_STR_LEN];

                        /* check src and dst address */
                        if (log_in_vain != 3)
                                log(LOG_INFO,
                                        "Connection attempt to UDP %s:%d from %s:%d\n",
                                        inet_ntop(AF_INET, &ip->ip_dst, buf, sizeof(buf)),
                                        ntohs(uh->uh_dport),
                                        inet_ntop(AF_INET, &ip->ip_src, buf2, sizeof(buf2)),
                                        ntohs(uh->uh_sport));
                        else if (!(m->m_flags & (M_BCAST | M_MCAST)) &&
                                         ip->ip_dst.s_addr != ip->ip_src.s_addr)
                                log_in_vain_log((LOG_INFO,
                                        "Stealth Mode connection attempt to UDP %s:%d from %s:%d\n",
                                        inet_ntop(AF_INET, &ip->ip_dst, buf, sizeof(buf)),
                                        ntohs(uh->uh_dport),
                                        inet_ntop(AF_INET, &ip->ip_src, buf2, sizeof(buf2)),
                                        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)
                        if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type != IFT_LOOP)
                                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;
        }
        udp_lock(inp->inp_socket, 1, 0);

        if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
                udp_unlock(inp->inp_socket, 1, 0);
                goto bad;
        }
#if IPSEC
        if (ipsec_bypass == 0 && inp != NULL) {
                lck_mtx_lock(sadb_mutex);
                if (ipsec4_in_reject_so(m, inp->inp_socket)) {
                        ipsecstat.in_polvio++;
                        lck_mtx_unlock(sadb_mutex);
                        udp_unlock(inp->inp_socket, 1, 0);
                        goto bad;
                }
                lck_mtx_unlock(sadb_mutex);
        }
#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, NULL) == 0) {
                udpstat.udps_fullsock++;
        }
        else {
                sorwakeup(inp->inp_socket);
        }
        udp_unlock(inp->inp_socket, 1, 0);
        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, NULL) == 0) {
                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)(struct inpcb *, int) = udp_notify;
        struct in_addr faddr;
        struct inpcb *inp;

        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) {
                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) {
                        udp_lock(inp->inp_socket, 1, 0);
                        if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING)  {
                                udp_unlock(inp->inp_socket, 1, 0);
                                return;
                        }
                        (*notify)(inp, inetctlerrmap[cmd]);
                        udp_unlock(inp->inp_socket, 1, 0);
                }
        } else
                in_pcbnotifyall(&udbinfo, faddr, inetctlerrmap[cmd], notify);
}

static int
udp_pcblist SYSCTL_HANDLER_ARGS
{
        int error, i, n;
        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.
         */
        lck_rw_lock_exclusive(udbinfo.mtx);
        if (req->oldptr == USER_ADDR_NULL) {
                n = udbinfo.ipi_count;
                req->oldidx = 2 * (sizeof xig)
                        + (n + n/8) * sizeof(struct xinpcb);
                lck_rw_done(udbinfo.mtx);
                return 0;
        }

        if (req->newptr != USER_ADDR_NULL) {
                lck_rw_done(udbinfo.mtx);
                return EPERM;
        }

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

        bzero(&xig, sizeof(xig));
        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) {
                lck_rw_done(udbinfo.mtx);
                return error;
        }
    /*
     * We are done if there is no pcb
     */
    if (n == 0) {
        lck_rw_done(udbinfo.mtx);
        return 0; 
    }

        inp_list = _MALLOC(n * sizeof *inp_list, M_TEMP, M_WAITOK);
        if (inp_list == 0) {
                lck_rw_done(udbinfo.mtx);
                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->inp_state != INPCB_STATE_DEAD)
                        inp_list[i++] = inp;
        }
        n = i;

        error = 0;
        for (i = 0; i < n; i++) {
                inp = inp_list[i];
                if (inp->inp_gencnt <= gencnt && inp->inp_state != INPCB_STATE_DEAD) {
                        struct xinpcb xi;

                        bzero(&xi, sizeof(xi));
                        xi.xi_len = sizeof xi;
                        /* XXX should avoid extra copy */
                        inpcb_to_compat(inp, &xi.xi_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.
                 */
                bzero(&xig, sizeof(xig));
                xig.xig_len = sizeof xig;
                xig.xig_gen = udbinfo.ipi_gencnt;
                xig.xig_sogen = so_gencnt;
                xig.xig_count = udbinfo.ipi_count;
                error = SYSCTL_OUT(req, &xig, sizeof xig);
        }
        FREE(inp_list, M_TEMP);
        lck_rw_done(udbinfo.mtx);
        return error;
}

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



static __inline__ u_int16_t
get_socket_id(struct socket * s)
{
        u_int16_t               val;

        if (s == NULL) {
            return (0);
        }
        val = (u_int16_t)(((u_int32_t)s) / sizeof(struct socket));
        if (val == 0) {
                val = 0xffff;
        }
        return (val);
}

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 sockaddr_in *sin, src;
        struct in_addr origladdr, laddr, faddr;
        u_short lport, fport;
        struct sockaddr_in *ifaddr;
        int error = 0, udp_dodisconnect = 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 there was a routing change, discard cached route and check
         * that we have a valid source address. 
         * Reacquire a new source address if INADDR_ANY was specified
         */

#if 1
        lck_mtx_assert(inp->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
#endif

        if (inp->inp_route.ro_rt && inp->inp_route.ro_rt->generation_id != route_generation) {
                if (ifa_foraddr(inp->inp_laddr.s_addr) == 0) { /* src address is gone */
                        if (inp->inp_flags & INP_INADDR_ANY)
                                inp->inp_faddr.s_addr = INADDR_ANY; /* new src will be set later */
                        else {
                                error = EADDRNOTAVAIL;
                                goto release;
                        }
                }
                rtfree(inp->inp_route.ro_rt);
                inp->inp_route.ro_rt = (struct rtentry *)0;
        }

        origladdr= laddr = inp->inp_laddr;
        faddr = inp->inp_faddr;
        lport = inp->inp_lport;
        fport = inp->inp_fport;

        if (addr) {
                sin = (struct sockaddr_in *)addr;
                if (faddr.s_addr != INADDR_ANY) {
                        error = EISCONN;
                        goto release;
                }
                if (lport == 0) {
                        /*
                         * In case we don't have a local port set, go through the full connect.
                         * We don't have a local port yet (ie, we can't be looked up),
                         * so it's not an issue if the input runs at the same time we do this.
                         */
                        error = in_pcbconnect(inp, addr, p);
                        if (error) {
                                goto release;
                        }
                        laddr = inp->inp_laddr;
                        lport = inp->inp_lport;
                        faddr = inp->inp_faddr;
                        fport = inp->inp_fport;
                        udp_dodisconnect = 1;
                }
                else {  
                        /* Fast path case
                         * we have a full address and a local port.
                         * use those info to build the packet without changing the pcb
                         * and interfering with the input path. See 3851370
                         */
                        if (laddr.s_addr == INADDR_ANY) {
                           if ((error = in_pcbladdr(inp, addr, &ifaddr)) != 0)
                                   goto release;
                           laddr = ifaddr->sin_addr;
                           inp->inp_flags |= INP_INADDR_ANY; /* from pcbconnect: remember we don't care about src addr.*/
                        }
                                   
                        faddr = sin->sin_addr;
                        fport = sin->sin_port;
                }
        } else {
                if (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;
                goto abort;
        }

        /*
         * 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 = laddr;
        ui->ui_dst = faddr;
        ui->ui_sport = lport;
        ui->ui_dport = 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 abort;
        }
#endif /*IPSEC*/
        m->m_pkthdr.socket_id = get_socket_id(inp->inp_socket);
        error = ip_output_list(m, 0,  inp->inp_options, &inp->inp_route,
            (inp->inp_socket->so_options & (SO_DONTROUTE | SO_BROADCAST)),
            inp->inp_moptions);

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

abort:
        if (udp_dodisconnect) {
                in_pcbdisconnect(inp);
                inp->inp_laddr = origladdr; /* XXX rehash? */
        }

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;

        inp = sotoinpcb(so);
        if (inp == 0)
                panic("udp_abort: so=%x null inp\n", so);       /* ??? possible? panic instead? */
        soisdisconnected(so);
        in_pcbdetach(inp);
        return 0;
}

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

        inp = sotoinpcb(so);
        if (inp != 0)
                panic ("udp_attach so=%x inp=%x\n", so, inp);

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

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

static int
udp_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_faddr.s_addr != INADDR_ANY)
                return EISCONN;
        error = in_pcbconnect(inp, nam, p);
        if (error == 0) 
                soisconnected(so);
        return error;
}

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

        inp = sotoinpcb(so);
        if (inp == 0)
                panic("udp_detach: so=%x null inp\n", so);      /* ??? possible? panic instead? */
        in_pcbdetach(inp);
        inp->inp_state = INPCB_STATE_DEAD;
        return 0;
}

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

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

        in_pcbdisconnect(inp);
        inp->inp_laddr.s_addr = INADDR_ANY;
        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, pru_sopoll_notsupp
};


int
udp_lock(so, refcount, debug)
        struct socket *so;
        int refcount, debug;
{
        int lr_saved;
#ifdef __ppc__
        if (debug == 0) {
                __asm__ volatile("mflr %0" : "=r" (lr_saved));
        }
        else lr_saved = debug;
#endif

        if (so->so_pcb) {
                lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_NOTOWNED);
                lck_mtx_lock(((struct inpcb *)so->so_pcb)->inpcb_mtx);
        }
        else {
                panic("udp_lock: so=%x NO PCB! lr=%x\n", so, lr_saved);
                lck_mtx_assert(so->so_proto->pr_domain->dom_mtx, LCK_MTX_ASSERT_NOTOWNED);
                lck_mtx_lock(so->so_proto->pr_domain->dom_mtx);
        }

        if (refcount) 
                so->so_usecount++;

        so->reserved3= lr_saved;
        return (0);
}

int
udp_unlock(so, refcount, debug)
        struct socket *so;
        int refcount;
        int debug;
{
        int lr_saved;
        struct inpcb *inp = sotoinpcb(so);
        struct inpcbinfo *pcbinfo       = &udbinfo;
#ifdef __ppc__
        if (debug == 0) {
                __asm__ volatile("mflr %0" : "=r" (lr_saved));
        }
        else lr_saved = debug;
#endif
        if (refcount) {
                so->so_usecount--;
#if 0
                if (so->so_usecount == 0 && (inp->inp_wantcnt == WNT_STOPUSING)) {
                        if (lck_rw_try_lock_exclusive(pcbinfo->mtx)) {
                                in_pcbdispose(inp);
                                lck_rw_done(pcbinfo->mtx);
                                return(0);
                        }
                }
#endif
        }
        if (so->so_pcb == NULL) {
                panic("udp_unlock: so=%x NO PCB! lr=%x\n", so, lr_saved);
                lck_mtx_assert(so->so_proto->pr_domain->dom_mtx, LCK_MTX_ASSERT_OWNED);
                lck_mtx_unlock(so->so_proto->pr_domain->dom_mtx);
        }
        else {
                lck_mtx_assert(((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
                lck_mtx_unlock(((struct inpcb *)so->so_pcb)->inpcb_mtx);
        }


        so->reserved4 = lr_saved;
        return (0);
}

lck_mtx_t *
udp_getlock(so, locktype)
        struct socket *so;
        int locktype;
{
        struct inpcb *inp = sotoinpcb(so);


        if (so->so_pcb)
                return(inp->inpcb_mtx);
        else {
                panic("udp_getlock: so=%x NULL so_pcb\n", so);
                return (so->so_proto->pr_domain->dom_mtx);
        }
}

void
udp_slowtimo()
{
        struct inpcb *inp, *inpnxt;
        struct socket *so;
        struct inpcbinfo *pcbinfo       = &udbinfo;

        lck_rw_lock_exclusive(pcbinfo->mtx);

        for (inp = udb.lh_first; inp != NULL; inp = inpnxt) {
                inpnxt = inp->inp_list.le_next;
        
                /* Ignore nat/SharedIP dummy pcbs */
                if (inp->inp_socket == &udbinfo.nat_dummy_socket)
                                continue;

                if (inp->inp_wantcnt != WNT_STOPUSING) 
                        continue;

                so = inp->inp_socket;
                if (!lck_mtx_try_lock(inp->inpcb_mtx))  /* skip if busy, no hurry for cleanup... */
                        continue;

                if (so->so_usecount == 0)
                        in_pcbdispose(inp);
                else 
                        lck_mtx_unlock(inp->inpcb_mtx);
        }
        lck_rw_done(pcbinfo->mtx);
}

int
ChkAddressOK( __uint32_t dstaddr, __uint32_t srcaddr )
{
        if ( dstaddr == srcaddr ){
                return 0;
        }
        return 1;
}