HAMMER 60I/Many: Mirroring

[dragonfly.git] / sys / netinet / udp_usrreq.c

/*
 * Copyright (c) 2004 Jeffrey M. Hsu.  All rights reserved.
 * Copyright (c) 2004 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Jeffrey M. Hsu.
 *
 * 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 DragonFly 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 COPYRIGHT HOLDERS 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
 * COPYRIGHT HOLDERS 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, 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 1.64.2.18 2003/01/24 05:11:34 sam Exp $
 * $DragonFly: src/sys/netinet/udp_usrreq.c,v 1.44 2008/04/26 14:08:52 sephe Exp $
 */

#include "opt_ipsec.h"
#include "opt_inet6.h"

#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/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/thread2.h>
#include <sys/in_cksum.h>

#include <machine/stdarg.h>

#include <vm/vm_zone.h>

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

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#ifdef INET6
#include <netinet/ip6.h>
#endif
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#ifdef 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>

#ifdef FAST_IPSEC
#include <netproto/ipsec/ipsec.h>
#endif

#ifdef IPSEC
#include <netinet6/ipsec.h>
#endif

/*
 * 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");

static int      strict_mcast_mship = 1;
SYSCTL_INT(_net_inet_udp, OID_AUTO, strict_mcast_mship, CTLFLAG_RW,
        &strict_mcast_mship, 0, "Only send multicast to member sockets");

struct  inpcbinfo udbinfo;

#ifndef UDBHASHSIZE
#define UDBHASHSIZE 16
#endif

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

static struct   sockaddr_in udp_in = { sizeof udp_in, AF_INET };
#ifdef 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);
#ifdef 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 thread *);

void
udp_init(void)
{
        in_pcbinfo_init(&udbinfo);
        udbinfo.hashbase = hashinit(UDBHASHSIZE, M_PCB, &udbinfo.hashmask);
        udbinfo.porthashbase = hashinit(UDBHASHSIZE, M_PCB,
                                        &udbinfo.porthashmask);
        udbinfo.wildcardhashbase = hashinit(UDBHASHSIZE, M_PCB,
                                            &udbinfo.wildcardhashmask);
        udbinfo.ipi_zone = zinit("udpcb", sizeof(struct inpcb), maxsockets,
                                 ZONE_INTERRUPT, 0);
        udp_thread_init();
}

/*
 * Check multicast packets to make sure they are only sent to sockets with
 * multicast memberships for the packet's destination address and arrival
 * interface.  Multicast packets to multicast-unaware sockets are also
 * disallowed.
 *
 * Returns 0 if the packet is acceptable, -1 if it is not.
 */
static __inline int
check_multicast_membership(struct ip *ip, struct inpcb *inp, struct mbuf *m)
{
        int mshipno;
        struct ip_moptions *mopt;

        if (strict_mcast_mship == 0 ||
            !IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
                return (0);
        }
        mopt = inp->inp_moptions;
        if (mopt == NULL)
                return (-1);
        for (mshipno = 0; mshipno <= mopt->imo_num_memberships; ++mshipno) {
                struct in_multi *maddr = mopt->imo_membership[mshipno];

                if (ip->ip_dst.s_addr == maddr->inm_addr.s_addr &&
                    m->m_pkthdr.rcvif == maddr->inm_ifp) {
                        return (0);
                }
        }
        return (-1);
}

void
udp_input(struct mbuf *m, ...)
{
        int iphlen;
        struct ip *ip;
        struct udphdr *uh;
        struct inpcb *inp;
        struct mbuf *opts = NULL;
        int len, off, proto;
        struct ip save_ip;
        struct sockaddr *append_sa;
        __va_list ap;

        __va_start(ap, m);
        off = __va_arg(ap, int);
        proto = __va_arg(ap, int);
        __va_end(ap);

        iphlen = off;
        udpstat.udps_ipackets++;

        /*
         * 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);
                iphlen = sizeof(struct ip);
        }

        /*
         * IP and UDP headers are together in first mbuf.
         * Already checked and pulled up in ip_demux().
         */
        KASSERT(m->m_len >= iphlen + sizeof(struct udphdr),
            ("UDP header not in one mbuf"));

        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;

        /*
         * 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
                                uh->uh_sum = in_pseudo(ip->ip_src.s_addr,
                                    ip->ip_dst.s_addr, htonl((u_short)len +
                                    m->m_pkthdr.csum_data + IPPROTO_UDP));
                        uh->uh_sum ^= 0xffff;
                } else {
                        char b[9];

                        bcopy(((struct ipovly *)ip)->ih_x1, b, 9);
                        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));
                        bcopy(b, ((struct ipovly *)ip)->ih_x1, 9);
                }
                if (uh->uh_sum) {
                        udpstat.udps_badsum++;
                        m_freem(m);
                        return;
                }
        } else
                udpstat.udps_nosum++;

        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;
#ifdef INET6
                udp_in6.uin6_init_done = udp_ip6.uip6_init_done = 0;
#endif
                LIST_FOREACH(inp, &udbinfo.pcblisthead, inp_list) {
                        if (inp->inp_flags & INP_PLACEMARKER)
                                continue;
#ifdef INET6
                        if (!(inp->inp_vflag & INP_IPV4))
                                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 (check_multicast_membership(ip, inp, m) < 0)
                                continue;

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

#ifdef IPSEC
                                /* check AH/ESP integrity. */
                                if (ipsec4_in_reject_so(m, last->inp_socket))
                                        ipsecstat.in_polvio++;
                                        /* do not inject data to pcb */
                                else
#endif /*IPSEC*/
#ifdef FAST_IPSEC
                                /* check AH/ESP integrity. */
                                if (ipsec4_in_reject(m, last))
                                        ;
                                else
#endif /*FAST_IPSEC*/
                                if ((n = m_copypacket(m, MB_DONTWAIT)) != 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)))
                                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;
                }
#ifdef IPSEC
                /* check AH/ESP integrity. */
                if (ipsec4_in_reject_so(m, last->inp_socket)) {
                        ipsecstat.in_polvio++;
                        goto bad;
                }
#endif /*IPSEC*/
#ifdef FAST_IPSEC
                /* check AH/ESP integrity. */
                if (ipsec4_in_reject(m, last))
                        goto bad;
#endif /*FAST_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[sizeof "aaa.bbb.ccc.ddd"];

                        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 (blackhole)
                        goto bad;
#ifdef ICMP_BANDLIM
                if (badport_bandlim(BANDLIM_ICMP_UNREACH) < 0)
                        goto bad;
#endif
                *ip = save_ip;
                ip->ip_len += iphlen;
                icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_PORT, 0, 0);
                return;
        }
#ifdef IPSEC
        if (ipsec4_in_reject_so(m, inp->inp_socket)) {
                ipsecstat.in_polvio++;
                goto bad;
        }
#endif /*IPSEC*/
#ifdef FAST_IPSEC
        if (ipsec4_in_reject(m, inp))
                goto bad;
#endif /*FAST_IPSEC*/
        /*
         * Check the minimum TTL for socket.
         */
        if (ip->ip_ttl < inp->inp_ip_minttl)
                goto bad;

        /*
         * 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)) {
#ifdef 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));
#ifdef 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 (ssb_appendaddr(&inp->inp_socket->so_rcv, append_sa, m, opts) == 0) {
                udpstat.udps_fullsock++;
                goto bad;
        }
        sorwakeup(inp->inp_socket);
        return;
bad:
        m_freem(m);
        if (opts)
                m_freem(opts);
        return;
}

#ifdef INET6
static void
ip_2_ip6_hdr(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(struct inpcb *last, struct ip *ip, struct mbuf *n, int off)
{
        struct sockaddr *append_sa;
        struct mbuf *opts = NULL;

        if (last->inp_flags & INP_CONTROLOPTS ||
            last->inp_socket->so_options & SO_TIMESTAMP) {
#ifdef 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);
        }
#ifdef 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 (ssb_appendaddr(&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(struct inpcb *inp, int error)
{
        inp->inp_socket->so_error = error;
        sorwakeup(inp->inp_socket);
        sowwakeup(inp->inp_socket);
}

void
udp_ctlinput(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 = NULL;
                notify = in_rtchange;
        } else if (cmd == PRC_HOSTDEAD)
                ip = NULL;
        else if ((unsigned)cmd >= PRC_NCMDS || inetctlerrmap[cmd] == 0)
                return;
        if (ip) {
                crit_enter();
                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]);
                crit_exit();
        } else
                in_pcbnotifyall(&udbinfo.pcblisthead, faddr, inetctlerrmap[cmd],
                                notify);
}

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

static int
udp_getcred(SYSCTL_HANDLER_ARGS)
{
        struct sockaddr_in addrs[2];
        struct inpcb *inp;
        int error;

        error = suser(req->td);
        if (error)
                return (error);
        error = SYSCTL_IN(req, addrs, sizeof addrs);
        if (error)
                return (error);
        crit_enter();
        inp = in_pcblookup_hash(&udbinfo, addrs[1].sin_addr, addrs[1].sin_port,
                                addrs[0].sin_addr, addrs[0].sin_port, 1, NULL);
        if (inp == NULL || inp->inp_socket == NULL) {
                error = ENOENT;
                goto out;
        }
        error = SYSCTL_OUT(req, inp->inp_socket->so_cred, sizeof(struct ucred));
out:
        crit_exit();
        return (error);
}

SYSCTL_PROC(_net_inet_udp, OID_AUTO, getcred, CTLTYPE_OPAQUE|CTLFLAG_RW,
    0, 0, udp_getcred, "S,ucred", "Get the ucred of a UDP connection");

static int
udp_output(struct inpcb *inp, struct mbuf *m, struct sockaddr *dstaddr,
           struct mbuf *control, struct thread *td)
{
        struct udpiphdr *ui;
        int len = m->m_pkthdr.len;
        struct sockaddr_in *sin;        /* really is initialized before use */
        int error = 0, lport_any = 0;

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

        if (inp->inp_lport == 0) {      /* unbound socket */
                error = in_pcbbind(inp, (struct sockaddr *)NULL, td);
                if (error)
                        goto release;
                in_pcbinswildcardhash(inp);
                lport_any = 1;
        }

        if (dstaddr != NULL) {          /* destination address specified */
                if (inp->inp_faddr.s_addr != INADDR_ANY) {
                        /* already connected */
                        error = EISCONN;
                        goto release;
                }
                sin = (struct sockaddr_in *)dstaddr;
                if (!prison_remote_ip(td, (struct sockaddr *)&sin)) {
                        error = EAFNOSUPPORT; /* IPv6 only jail */
                        goto release;
                }
        } else {
                if (inp->inp_faddr.s_addr == INADDR_ANY) {
                        /* no destination specified and not already connected */
                        error = ENOTCONN;
                        goto release;
                }
                sin = NULL;
        }

        /*
         * Calculate data length and get a mbuf
         * for UDP and IP headers.
         */
        M_PREPEND(m, sizeof(struct udpiphdr), MB_DONTWAIT);
        if (m == NULL) {
                error = ENOBUFS;
                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;

        /*
         * Set destination address.
         */
        if (dstaddr != NULL) {                  /* use specified destination */
                ui->ui_dst = sin->sin_addr;
                ui->ui_dport = sin->sin_port;
        } else {                                /* use connected destination */
                ui->ui_dst = inp->inp_faddr;
                ui->ui_dport = inp->inp_fport;
        }

        /*
         * Set source address.
         */
        if (inp->inp_laddr.s_addr == INADDR_ANY) {
                struct sockaddr_in *if_sin;

                if (dstaddr == NULL) {  
                        /*
                         * connect() had (or should have) failed because
                         * the interface had no IP address, but the
                         * application proceeded to call send() anyways.
                         */
                        error = ENOTCONN;
                        goto release;
                }

                /* Look up outgoing interface. */
                if ((error = in_pcbladdr(inp, dstaddr, &if_sin, td)))
                        goto release;
                ui->ui_src = if_sin->sin_addr;  /* use address of interface */
        } else {
                ui->ui_src = inp->inp_laddr;    /* use non-null bound address */
        }
        ui->ui_sport = inp->inp_lport;
        KASSERT(inp->inp_lport != 0, ("inp lport should have been bound"));

        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++;

        error = ip_output(m, inp->inp_options, &inp->inp_route,
            (inp->inp_socket->so_options & (SO_DONTROUTE | SO_BROADCAST)),
            inp->inp_moptions, inp);

        /*
         * If this is the first data gram sent on an unbound and unconnected
         * UDP socket, lport will be changed in this function.  If target
         * CPU after this lport changing is no longer the current CPU, then
         * free the route entry allocated on the current CPU.
         */
        if (lport_any) {
                if (udp_addrcpu(inp->inp_faddr.s_addr, inp->inp_laddr.s_addr,
                                inp->inp_fport, inp->inp_lport) != mycpuid) {
                        struct route *ro = &inp->inp_route;

                        if (ro->ro_rt != NULL)
                                RTFREE(ro->ro_rt);
                        bzero(ro, sizeof(*ro));
                }
        }
        return (error);

release:
        m_freem(m);
        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 +
#ifdef 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 = so->so_pcb;
        if (inp == NULL)
                return EINVAL;  /* ??? possible? panic instead? */
        soisdisconnected(so);
        crit_enter();
        in_pcbdetach(inp);
        crit_exit();
        return 0;
}

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

        inp = so->so_pcb;
        if (inp != NULL)
                return EINVAL;

        error = soreserve(so, udp_sendspace, udp_recvspace, ai->sb_rlimit);
        if (error)
                return error;
        crit_enter();
        error = in_pcballoc(so, &udbinfo);
        crit_exit();
        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 thread *td)
{
        struct sockaddr_in *sin = (struct sockaddr_in *)nam;
        struct inpcb *inp;
        int error;

        inp = so->so_pcb;
        if (inp == NULL)
                return EINVAL;
        crit_enter();
        error = in_pcbbind(inp, nam, td);
        crit_exit();
        if (error == 0) {
                if (sin->sin_addr.s_addr != INADDR_ANY)
                        inp->inp_flags |= INP_WASBOUND_NOTANY;
                in_pcbinswildcardhash(inp);
        }
        return error;
}

static int
udp_connect(struct socket *so, struct sockaddr *nam, struct thread *td)
{
        struct inpcb *inp;
        int error;

        inp = so->so_pcb;
        if (inp == NULL)
                return EINVAL;
        if (inp->inp_faddr.s_addr != INADDR_ANY)
                return EISCONN;
        error = 0;
        crit_enter();
        if (td->td_proc && td->td_proc->p_ucred->cr_prison != NULL &&
            inp->inp_laddr.s_addr == INADDR_ANY) {
                error = in_pcbbind(inp, NULL, td);
        }
        if (error == 0) {
                if (!prison_remote_ip(td, nam))
                        return(EAFNOSUPPORT); /* IPv6 only jail */
                if (inp->inp_flags & INP_WILDCARD)
                        in_pcbremwildcardhash(inp);
                error = in_pcbconnect(inp, nam, td);
        }
        crit_exit();
        if (error == 0) {
                soisconnected(so);

                /*
                 * Make sure that the new target CPU is same as current CPU,
                 * if it is not, then we will have to free the route entry
                 * allocated on the current CPU.
                 */
                if (udp_addrcpu(inp->inp_faddr.s_addr, inp->inp_laddr.s_addr,
                                inp->inp_fport, inp->inp_lport) != mycpuid) {
                        struct route *ro = &inp->inp_route;

                        if (ro->ro_rt != NULL)
                                RTFREE(ro->ro_rt);
                        bzero(ro, sizeof(*ro));
                }
        } else if (error == EAFNOSUPPORT) {     /* connection dissolved */
                /*
                 * Follow traditional BSD behavior and retain
                 * the local port binding.  But, fix the old misbehavior
                 * of overwriting any previously bound local address.
                 */
                if (!(inp->inp_flags & INP_WASBOUND_NOTANY))
                        inp->inp_laddr.s_addr = INADDR_ANY;
                in_pcbinswildcardhash(inp);
        }
        return error;
}

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

        inp = so->so_pcb;
        if (inp == NULL)
                return EINVAL;
        crit_enter();
        in_pcbdetach(inp);
        crit_exit();
        return 0;
}

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

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

        crit_enter();
        in_pcbdisconnect(inp);
        crit_exit();
        so->so_state &= ~SS_ISCONNECTED;                /* XXX */

        ro = &inp->inp_route;
        if (ro->ro_rt != NULL)
                RTFREE(ro->ro_rt);
        bzero(ro, sizeof(*ro));

        return 0;
}

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

        inp = so->so_pcb;
        if (inp == NULL) {
                m_freem(m);
                return EINVAL;
        }
        return udp_output(inp, m, addr, control, td);
}

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

        inp = so->so_pcb;
        if (inp == NULL)
                return EINVAL;
        socantsendmore(so);
        return 0;
}

struct pr_usrreqs udp_usrreqs = {
        .pru_abort = udp_abort,
        .pru_accept = pru_accept_notsupp,
        .pru_attach = udp_attach,
        .pru_bind = udp_bind,
        .pru_connect = udp_connect,
        .pru_connect2 = pru_connect2_notsupp,
        .pru_control = in_control,
        .pru_detach = udp_detach,
        .pru_disconnect = udp_disconnect,
        .pru_listen = pru_listen_notsupp,
        .pru_peeraddr = in_setpeeraddr,
        .pru_rcvd = pru_rcvd_notsupp,
        .pru_rcvoob = pru_rcvoob_notsupp,
        .pru_send = udp_send,
        .pru_sense = pru_sense_null,
        .pru_shutdown = udp_shutdown,
        .pru_sockaddr = in_setsockaddr,
        .pru_sosend = sosendudp,
        .pru_soreceive = soreceive,
        .pru_sopoll = sopoll
};