/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 1995 Søren Schmidt
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include "opt_inet6.h"

#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/filedesc.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/proc.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/syscallsubr.h>
#include <sys/sysproto.h>
#include <sys/vnode.h>
#include <sys/un.h>
#include <sys/unistd.h>

#include <security/audit/audit.h>

#include <net/if.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#endif

#ifdef COMPAT_LINUX32
#include <compat/freebsd32/freebsd32_util.h>
#include <machine/../linux32/linux.h>
#include <machine/../linux32/linux32_proto.h>
#else
#include <machine/../linux/linux.h>
#include <machine/../linux/linux_proto.h>
#endif
#include <compat/linux/linux_common.h>
#include <compat/linux/linux_emul.h>
#include <compat/linux/linux_file.h>
#include <compat/linux/linux_mib.h>
#include <compat/linux/linux_socket.h>
#include <compat/linux/linux_time.h>
#include <compat/linux/linux_util.h>

_Static_assert(offsetof(struct l_ifreq, ifr_ifru) ==
    offsetof(struct ifreq, ifr_ifru),
    "Linux ifreq members names should be equal to FreeeBSD");
_Static_assert(offsetof(struct l_ifreq, ifr_index) ==
    offsetof(struct ifreq, ifr_index),
    "Linux ifreq members names should be equal to FreeeBSD");
_Static_assert(offsetof(struct l_ifreq, ifr_name) ==
    offsetof(struct ifreq, ifr_name),
    "Linux ifreq members names should be equal to FreeeBSD");

#define SECURITY_CONTEXT_STRING "unconfined"

static int linux_sendmsg_common(struct thread *, l_int, struct l_msghdr *,
                                        l_uint);
static int linux_recvmsg_common(struct thread *, l_int, struct l_msghdr *,
                                        l_uint, struct msghdr *);
static int linux_set_socket_flags(int, int *);

#define SOL_NETLINK     270

static int
linux_to_bsd_sockopt_level(int level)
{

        if (level == LINUX_SOL_SOCKET)
                return (SOL_SOCKET);
        /* Remaining values are RFC-defined protocol numbers. */
        return (level);
}

static int
bsd_to_linux_sockopt_level(int level)
{

        if (level == SOL_SOCKET)
                return (LINUX_SOL_SOCKET);
        return (level);
}

static int
linux_to_bsd_ip_sockopt(int opt)
{

        switch (opt) {
        /* known and translated sockopts */
        case LINUX_IP_TOS:
                return (IP_TOS);
        case LINUX_IP_TTL:
                return (IP_TTL);
        case LINUX_IP_HDRINCL:
                return (IP_HDRINCL);
        case LINUX_IP_OPTIONS:
                return (IP_OPTIONS);
        case LINUX_IP_RECVOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_RECVOPTS");
                return (IP_RECVOPTS);
        case LINUX_IP_RETOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_REETOPTS");
                return (IP_RETOPTS);
        case LINUX_IP_RECVTTL:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_RECVTTL");
                return (IP_RECVTTL);
        case LINUX_IP_RECVTOS:
                return (IP_RECVTOS);
        case LINUX_IP_FREEBIND:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_FREEBIND");
                return (IP_BINDANY);
        case LINUX_IP_IPSEC_POLICY:
                /* we have this option, but not documented in ip(4) manpage */
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_IPSEC_POLICY");
                return (IP_IPSEC_POLICY);
        case LINUX_IP_MINTTL:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_MINTTL");
                return (IP_MINTTL);
        case LINUX_IP_MULTICAST_IF:
                return (IP_MULTICAST_IF);
        case LINUX_IP_MULTICAST_TTL:
                return (IP_MULTICAST_TTL);
        case LINUX_IP_MULTICAST_LOOP:
                return (IP_MULTICAST_LOOP);
        case LINUX_IP_ADD_MEMBERSHIP:
                return (IP_ADD_MEMBERSHIP);
        case LINUX_IP_DROP_MEMBERSHIP:
                return (IP_DROP_MEMBERSHIP);
        case LINUX_IP_UNBLOCK_SOURCE:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_UNBLOCK_SOURCE");
                return (IP_UNBLOCK_SOURCE);
        case LINUX_IP_BLOCK_SOURCE:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_BLOCK_SOURCE");
                return (IP_BLOCK_SOURCE);
        case LINUX_IP_ADD_SOURCE_MEMBERSHIP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_ADD_SOURCE_MEMBERSHIP");
                return (IP_ADD_SOURCE_MEMBERSHIP);
        case LINUX_IP_DROP_SOURCE_MEMBERSHIP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_DROP_SOURCE_MEMBERSHIP");
                return (IP_DROP_SOURCE_MEMBERSHIP);
        case LINUX_MCAST_JOIN_GROUP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_MCAST_JOIN_GROUP");
                return (MCAST_JOIN_GROUP);
        case LINUX_MCAST_LEAVE_GROUP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_MCAST_LEAVE_GROUP");
                return (MCAST_LEAVE_GROUP);
        case LINUX_MCAST_JOIN_SOURCE_GROUP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_MCAST_JOIN_SOURCE_GROUP");
                return (MCAST_JOIN_SOURCE_GROUP);
        case LINUX_MCAST_LEAVE_SOURCE_GROUP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv4 socket option IP_MCAST_LEAVE_SOURCE_GROUP");
                return (MCAST_LEAVE_SOURCE_GROUP);
        case LINUX_IP_RECVORIGDSTADDR:
                return (IP_RECVORIGDSTADDR);

        /* known but not implemented sockopts */
        case LINUX_IP_ROUTER_ALERT:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_ROUTER_ALERT (%d), you can not do user-space routing from linux programs",
                    opt);
                return (-2);
        case LINUX_IP_PKTINFO:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_PKTINFO (%d), you can not get extended packet info for datagram sockets in linux programs",
                    opt);
                return (-2);
        case LINUX_IP_PKTOPTIONS:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_PKTOPTIONS (%d)",
                    opt);
                return (-2);
        case LINUX_IP_MTU_DISCOVER:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_MTU_DISCOVER (%d), your linux program can not control path-MTU discovery",
                    opt);
                return (-2);
        case LINUX_IP_RECVERR:
                /* needed by steam */
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_RECVERR (%d), you can not get extended reliability info in linux programs",
                    opt);
                return (-2);
        case LINUX_IP_MTU:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_MTU (%d), your linux program can not control the MTU on this socket",
                    opt);
                return (-2);
        case LINUX_IP_XFRM_POLICY:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_XFRM_POLICY (%d)",
                    opt);
                return (-2);
        case LINUX_IP_PASSSEC:
                /* needed by steam */
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_PASSSEC (%d), you can not get IPSEC related credential information associated with this socket in linux programs -- if you do not use IPSEC, you can ignore this",
                    opt);
                return (-2);
        case LINUX_IP_TRANSPARENT:
                /* IP_BINDANY or more? */
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_TRANSPARENT (%d), you can not enable transparent proxying in linux programs -- note, IP_FREEBIND is supported, no idea if the FreeBSD IP_BINDANY is equivalent to the Linux IP_TRANSPARENT or not, any info is welcome",
                    opt);
                return (-2);
        case LINUX_IP_NODEFRAG:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_NODEFRAG (%d)",
                    opt);
                return (-2);
        case LINUX_IP_CHECKSUM:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_CHECKSUM (%d)",
                    opt);
                return (-2);
        case LINUX_IP_BIND_ADDRESS_NO_PORT:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_BIND_ADDRESS_NO_PORT (%d)",
                    opt);
                return (-2);
        case LINUX_IP_RECVFRAGSIZE:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_RECVFRAGSIZE (%d)",
                    opt);
                return (-2);
        case LINUX_MCAST_MSFILTER:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_MCAST_MSFILTER (%d)",
                    opt);
                return (-2);
        case LINUX_IP_MULTICAST_ALL:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_MULTICAST_ALL (%d), your linux program will not see all multicast groups joined by the entire system, only those the program joined itself on this socket",
                    opt);
                return (-2);
        case LINUX_IP_UNICAST_IF:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv4 socket option IP_UNICAST_IF (%d)",
                    opt);
                return (-2);

        /* unknown sockopts */
        default:
                return (-1);
        }
}

static int
linux_to_bsd_ip6_sockopt(int opt)
{

        switch (opt) {
        /* known and translated sockopts */
        case LINUX_IPV6_2292PKTINFO:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_2292PKTINFO");
                return (IPV6_2292PKTINFO);
        case LINUX_IPV6_2292HOPOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_2292HOPOPTS");
                return (IPV6_2292HOPOPTS);
        case LINUX_IPV6_2292DSTOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_2292DSTOPTS");
                return (IPV6_2292DSTOPTS);
        case LINUX_IPV6_2292RTHDR:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_2292RTHDR");
                return (IPV6_2292RTHDR);
        case LINUX_IPV6_2292PKTOPTIONS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_2292PKTOPTIONS");
                return (IPV6_2292PKTOPTIONS);
        case LINUX_IPV6_CHECKSUM:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_CHECKSUM");
                return (IPV6_CHECKSUM);
        case LINUX_IPV6_2292HOPLIMIT:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_2292HOPLIMIT");
                return (IPV6_2292HOPLIMIT);
        case LINUX_IPV6_NEXTHOP:
                return (IPV6_NEXTHOP);
        case LINUX_IPV6_UNICAST_HOPS:
                return (IPV6_UNICAST_HOPS);
        case LINUX_IPV6_MULTICAST_IF:
                return (IPV6_MULTICAST_IF);
        case LINUX_IPV6_MULTICAST_HOPS:
                return (IPV6_MULTICAST_HOPS);
        case LINUX_IPV6_MULTICAST_LOOP:
                return (IPV6_MULTICAST_LOOP);
        case LINUX_IPV6_ADD_MEMBERSHIP:
                return (IPV6_JOIN_GROUP);
        case LINUX_IPV6_DROP_MEMBERSHIP:
                return (IPV6_LEAVE_GROUP);
        case LINUX_IPV6_V6ONLY:
                return (IPV6_V6ONLY);
        case LINUX_IPV6_IPSEC_POLICY:
                /* we have this option, but not documented in ip6(4) manpage */
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_IPSEC_POLICY");
                return (IPV6_IPSEC_POLICY);
        case LINUX_MCAST_JOIN_GROUP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_JOIN_GROUP");
                return (IPV6_JOIN_GROUP);
        case LINUX_MCAST_LEAVE_GROUP:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_LEAVE_GROUP");
                return (IPV6_LEAVE_GROUP);
        case LINUX_IPV6_RECVPKTINFO:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RECVPKTINFO");
                return (IPV6_RECVPKTINFO);
        case LINUX_IPV6_PKTINFO:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_PKTINFO");
                return (IPV6_PKTINFO);
        case LINUX_IPV6_RECVHOPLIMIT:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RECVHOPLIMIT");
                return (IPV6_RECVHOPLIMIT);
        case LINUX_IPV6_HOPLIMIT:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_HOPLIMIT");
                return (IPV6_HOPLIMIT);
        case LINUX_IPV6_RECVHOPOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RECVHOPOPTS");
                return (IPV6_RECVHOPOPTS);
        case LINUX_IPV6_HOPOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_HOPOPTS");
                return (IPV6_HOPOPTS);
        case LINUX_IPV6_RTHDRDSTOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RTHDRDSTOPTS");
                return (IPV6_RTHDRDSTOPTS);
        case LINUX_IPV6_RECVRTHDR:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RECVRTHDR");
                return (IPV6_RECVRTHDR);
        case LINUX_IPV6_RTHDR:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RTHDR");
                return (IPV6_RTHDR);
        case LINUX_IPV6_RECVDSTOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RECVDSTOPTS");
                return (IPV6_RECVDSTOPTS);
        case LINUX_IPV6_DSTOPTS:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_DSTOPTS");
                return (IPV6_DSTOPTS);
        case LINUX_IPV6_RECVPATHMTU:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_RECVPATHMTU");
                return (IPV6_RECVPATHMTU);
        case LINUX_IPV6_PATHMTU:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_PATHMTU");
                return (IPV6_PATHMTU);
        case LINUX_IPV6_DONTFRAG:
                return (IPV6_DONTFRAG);
        case LINUX_IPV6_AUTOFLOWLABEL:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_AUTOFLOWLABEL");
                return (IPV6_AUTOFLOWLABEL);
        case LINUX_IPV6_ORIGDSTADDR:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_ORIGDSTADDR");
                return (IPV6_ORIGDSTADDR);
        case LINUX_IPV6_FREEBIND:
                LINUX_RATELIMIT_MSG_NOTTESTED("IPv6 socket option IPV6_FREEBIND");
                return (IPV6_BINDANY);

        /* known but not implemented sockopts */
        case LINUX_IPV6_ADDRFORM:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_ADDRFORM (%d), you linux program can not convert the socket to IPv4",
                    opt);
                return (-2);
        case LINUX_IPV6_AUTHHDR:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_AUTHHDR (%d), your linux program can not get the authentication header info of IPv6 packets",
                    opt);
                return (-2);
        case LINUX_IPV6_FLOWINFO:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_FLOWINFO (%d), your linux program can not get the flowid of IPv6 packets",
                    opt);
                return (-2);
        case LINUX_IPV6_ROUTER_ALERT:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_ROUTER_ALERT (%d), you can not do user-space routing from linux programs",
                    opt);
                return (-2);
        case LINUX_IPV6_MTU_DISCOVER:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_MTU_DISCOVER (%d), your linux program can not control path-MTU discovery",
                    opt);
                return (-2);
        case LINUX_IPV6_MTU:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_MTU (%d), your linux program can not control the MTU on this socket",
                    opt);
                return (-2);
        case LINUX_IPV6_JOIN_ANYCAST:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_JOIN_ANYCAST (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_LEAVE_ANYCAST:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_LEAVE_ANYCAST (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_MULTICAST_ALL:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_MULTICAST_ALL (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_ROUTER_ALERT_ISOLATE:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_ROUTER_ALERT_ISOLATE (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_FLOWLABEL_MGR:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_FLOWLABEL_MGR (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_FLOWINFO_SEND:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_FLOWINFO_SEND (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_XFRM_POLICY:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_XFRM_POLICY (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_HDRINCL:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_HDRINCL (%d)",
                    opt);
                return (-2);
        case LINUX_MCAST_BLOCK_SOURCE:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option MCAST_BLOCK_SOURCE (%d), your linux program may see more multicast stuff than it wants",
                    opt);
                return (-2);
        case LINUX_MCAST_UNBLOCK_SOURCE:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option MCAST_UNBLOCK_SOURCE (%d), your linux program may not see all the multicast stuff it wants",
                    opt);
                return (-2);
        case LINUX_MCAST_JOIN_SOURCE_GROUP:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option MCAST_JOIN_SOURCE_GROUP (%d), your linux program is not able to join a multicast source group",
                    opt);
                return (-2);
        case LINUX_MCAST_LEAVE_SOURCE_GROUP:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option MCAST_LEAVE_SOURCE_GROUP (%d), your linux program is not able to leave a multicast source group -- but it was also not able to join one, so no issue",
                    opt);
                return (-2);
        case LINUX_MCAST_MSFILTER:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option MCAST_MSFILTER (%d), your linux program can not manipulate the multicast filter, it may see more multicast data than it wants to see",
                    opt);
                return (-2);
        case LINUX_IPV6_ADDR_PREFERENCES:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_ADDR_PREFERENCES (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_MINHOPCOUNT:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_MINHOPCOUNT (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_TRANSPARENT:
                /* IP_BINDANY or more? */
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_TRANSPARENT (%d), you can not enable transparent proxying in linux programs -- note, IP_FREEBIND is supported, no idea if the FreeBSD IP_BINDANY is equivalent to the Linux IP_TRANSPARENT or not, any info is welcome",
                    opt);
                return (-2);
        case LINUX_IPV6_UNICAST_IF:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_UNICAST_IF (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_RECVFRAGSIZE:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_RECVFRAGSIZE (%d)",
                    opt);
                return (-2);
        case LINUX_IPV6_RECVERR:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported IPv6 socket option IPV6_RECVERR (%d), you can not get extended reliability info in linux programs",
                    opt);
                return (-2);

        /* unknown sockopts */
        default:
                return (-1);
        }
}

static int
linux_to_bsd_so_sockopt(int opt)
{

        switch (opt) {
        case LINUX_SO_DEBUG:
                return (SO_DEBUG);
        case LINUX_SO_REUSEADDR:
                return (SO_REUSEADDR);
        case LINUX_SO_TYPE:
                return (SO_TYPE);
        case LINUX_SO_ERROR:
                return (SO_ERROR);
        case LINUX_SO_DONTROUTE:
                return (SO_DONTROUTE);
        case LINUX_SO_BROADCAST:
                return (SO_BROADCAST);
        case LINUX_SO_SNDBUF:
        case LINUX_SO_SNDBUFFORCE:
                return (SO_SNDBUF);
        case LINUX_SO_RCVBUF:
        case LINUX_SO_RCVBUFFORCE:
                return (SO_RCVBUF);
        case LINUX_SO_KEEPALIVE:
                return (SO_KEEPALIVE);
        case LINUX_SO_OOBINLINE:
                return (SO_OOBINLINE);
        case LINUX_SO_LINGER:
                return (SO_LINGER);
        case LINUX_SO_REUSEPORT:
                return (SO_REUSEPORT_LB);
        case LINUX_SO_PASSCRED:
                return (LOCAL_CREDS_PERSISTENT);
        case LINUX_SO_PEERCRED:
                return (LOCAL_PEERCRED);
        case LINUX_SO_RCVLOWAT:
                return (SO_RCVLOWAT);
        case LINUX_SO_SNDLOWAT:
                return (SO_SNDLOWAT);
        case LINUX_SO_RCVTIMEO:
                return (SO_RCVTIMEO);
        case LINUX_SO_SNDTIMEO:
                return (SO_SNDTIMEO);
        case LINUX_SO_TIMESTAMPO:
        case LINUX_SO_TIMESTAMPN:
                return (SO_TIMESTAMP);
        case LINUX_SO_TIMESTAMPNSO:
        case LINUX_SO_TIMESTAMPNSN:
                return (SO_BINTIME);
        case LINUX_SO_ACCEPTCONN:
                return (SO_ACCEPTCONN);
        case LINUX_SO_PROTOCOL:
                return (SO_PROTOCOL);
        case LINUX_SO_DOMAIN:
                return (SO_DOMAIN);
        }
        return (-1);
}

static int
linux_to_bsd_tcp_sockopt(int opt)
{

        switch (opt) {
        case LINUX_TCP_NODELAY:
                return (TCP_NODELAY);
        case LINUX_TCP_MAXSEG:
                return (TCP_MAXSEG);
        case LINUX_TCP_CORK:
                return (TCP_NOPUSH);
        case LINUX_TCP_KEEPIDLE:
                return (TCP_KEEPIDLE);
        case LINUX_TCP_KEEPINTVL:
                return (TCP_KEEPINTVL);
        case LINUX_TCP_KEEPCNT:
                return (TCP_KEEPCNT);
        case LINUX_TCP_INFO:
                LINUX_RATELIMIT_MSG_OPT1(
                    "unsupported TCP socket option TCP_INFO (%d)", opt);
                return (-2);
        case LINUX_TCP_MD5SIG:
                return (TCP_MD5SIG);
        case LINUX_TCP_USER_TIMEOUT:
                return (TCP_MAXUNACKTIME);
        }
        return (-1);
}

static u_int
linux_to_bsd_tcp_user_timeout(l_uint linux_timeout)
{

        /*
         * Linux exposes TCP_USER_TIMEOUT in milliseconds while
         * TCP_MAXUNACKTIME uses whole seconds. Round up partial
         * seconds so a non-zero Linux timeout never becomes zero.
         */
        return (howmany(linux_timeout, 1000U));
}

static l_uint
bsd_to_linux_tcp_user_timeout(u_int bsd_timeout)
{

        if (bsd_timeout > UINT_MAX / 1000U)
                return (UINT_MAX);

        return (bsd_timeout * 1000U);
}

static int
linux_to_bsd_msg_flags(int flags)
{
        int ret_flags = 0;

        if (flags & LINUX_MSG_OOB)
                ret_flags |= MSG_OOB;
        if (flags & LINUX_MSG_PEEK)
                ret_flags |= MSG_PEEK;
        if (flags & LINUX_MSG_DONTROUTE)
                ret_flags |= MSG_DONTROUTE;
        if (flags & LINUX_MSG_CTRUNC)
                ret_flags |= MSG_CTRUNC;
        if (flags & LINUX_MSG_TRUNC)
                ret_flags |= MSG_TRUNC;
        if (flags & LINUX_MSG_DONTWAIT)
                ret_flags |= MSG_DONTWAIT;
        if (flags & LINUX_MSG_EOR)
                ret_flags |= MSG_EOR;
        if (flags & LINUX_MSG_WAITALL)
                ret_flags |= MSG_WAITALL;
        if (flags & LINUX_MSG_NOSIGNAL)
                ret_flags |= MSG_NOSIGNAL;
        if (flags & LINUX_MSG_PROXY)
                LINUX_RATELIMIT_MSG_OPT1("socket message flag MSG_PROXY (%d) not handled",
                    LINUX_MSG_PROXY);
        if (flags & LINUX_MSG_FIN)
                LINUX_RATELIMIT_MSG_OPT1("socket message flag MSG_FIN (%d) not handled",
                    LINUX_MSG_FIN);
        if (flags & LINUX_MSG_SYN)
                LINUX_RATELIMIT_MSG_OPT1("socket message flag MSG_SYN (%d) not handled",
                    LINUX_MSG_SYN);
        if (flags & LINUX_MSG_CONFIRM)
                LINUX_RATELIMIT_MSG_OPT1("socket message flag MSG_CONFIRM (%d) not handled",
                    LINUX_MSG_CONFIRM);
        if (flags & LINUX_MSG_RST)
                LINUX_RATELIMIT_MSG_OPT1("socket message flag MSG_RST (%d) not handled",
                    LINUX_MSG_RST);
        if (flags & LINUX_MSG_ERRQUEUE)
                LINUX_RATELIMIT_MSG_OPT1("socket message flag MSG_ERRQUEUE (%d) not handled",
                    LINUX_MSG_ERRQUEUE);
        return (ret_flags);
}

static int
linux_to_bsd_cmsg_type(int cmsg_type)
{

        switch (cmsg_type) {
        case LINUX_SCM_RIGHTS:
                return (SCM_RIGHTS);
        case LINUX_SCM_CREDENTIALS:
                return (SCM_CREDS);
        }
        return (-1);
}

static int
bsd_to_linux_ip_cmsg_type(int cmsg_type)
{

        switch (cmsg_type) {
        case IP_RECVORIGDSTADDR:
                return (LINUX_IP_RECVORIGDSTADDR);
        case IP_RECVTOS:
                return (LINUX_IP_TOS);
        }
        return (-1);
}

static int
bsd_to_linux_cmsg_type(struct proc *p, int cmsg_type, int cmsg_level)
{
        struct linux_pemuldata *pem;

        if (cmsg_level == IPPROTO_IP)
                return (bsd_to_linux_ip_cmsg_type(cmsg_type));
        if (cmsg_level != SOL_SOCKET)
                return (-1);

        pem = pem_find(p);

        switch (cmsg_type) {
        case SCM_RIGHTS:
                return (LINUX_SCM_RIGHTS);
        case SCM_CREDS:
                return (LINUX_SCM_CREDENTIALS);
        case SCM_CREDS2:
                return (LINUX_SCM_CREDENTIALS);
        case SCM_TIMESTAMP:
                return (pem->so_timestamp);
        case SCM_BINTIME:
                return (pem->so_timestampns);
        }
        return (-1);
}

static int
linux_to_bsd_msghdr(struct msghdr *bhdr, const struct l_msghdr *lhdr)
{
        if (lhdr->msg_controllen > INT_MAX)
                return (ENOBUFS);

        bhdr->msg_name          = PTRIN(lhdr->msg_name);
        bhdr->msg_namelen       = lhdr->msg_namelen;
        bhdr->msg_iov           = PTRIN(lhdr->msg_iov);
        bhdr->msg_iovlen        = lhdr->msg_iovlen;
        bhdr->msg_control       = PTRIN(lhdr->msg_control);

        /*
         * msg_controllen is skipped since BSD and LINUX control messages
         * are potentially different sizes (e.g. the cred structure used
         * by SCM_CREDS is different between the two operating system).
         *
         * The caller can set it (if necessary) after converting all the
         * control messages.
         */

        bhdr->msg_flags         = linux_to_bsd_msg_flags(lhdr->msg_flags);
        return (0);
}

static int
bsd_to_linux_msghdr(const struct msghdr *bhdr, struct l_msghdr *lhdr)
{
        lhdr->msg_name          = PTROUT(bhdr->msg_name);
        lhdr->msg_namelen       = bhdr->msg_namelen;
        lhdr->msg_iov           = PTROUT(bhdr->msg_iov);
        lhdr->msg_iovlen        = bhdr->msg_iovlen;
        lhdr->msg_control       = PTROUT(bhdr->msg_control);

        /*
         * msg_controllen is skipped since BSD and LINUX control messages
         * are potentially different sizes (e.g. the cred structure used
         * by SCM_CREDS is different between the two operating system).
         *
         * The caller can set it (if necessary) after converting all the
         * control messages.
         */

        /* msg_flags skipped */
        return (0);
}

static int
linux_set_socket_flags(int lflags, int *flags)
{

        if (lflags & ~(LINUX_SOCK_CLOEXEC | LINUX_SOCK_NONBLOCK))
                return (EINVAL);
        if (lflags & LINUX_SOCK_NONBLOCK)
                *flags |= SOCK_NONBLOCK;
        if (lflags & LINUX_SOCK_CLOEXEC)
                *flags |= SOCK_CLOEXEC;
        return (0);
}

static int
linux_copyout_sockaddr(const struct sockaddr *sa, void *uaddr, size_t len)
{
        struct l_sockaddr *lsa;
        int error;

        error = bsd_to_linux_sockaddr(sa, &lsa, len);
        if (error != 0)
                return (error);

        error = copyout(lsa, uaddr, len);
        free(lsa, M_LINUX);

        return (error);
}

static int
linux_sendit(struct thread *td, int s, struct msghdr *mp, int flags,
    struct mbuf *control, enum uio_seg segflg)
{
        struct sockaddr *to;
        int error, len;

        if (mp->msg_name != NULL) {
                len = mp->msg_namelen;
                error = linux_to_bsd_sockaddr(mp->msg_name, &to, &len);
                if (error != 0)
                        return (error);
                mp->msg_name = to;
        } else
                to = NULL;

        error = kern_sendit(td, s, mp, linux_to_bsd_msg_flags(flags), control,
            segflg);

        if (to)
                free(to, M_SONAME);
        return (error);
}

/* Return 0 if IP_HDRINCL is set for the given socket. */
static int
linux_check_hdrincl(struct thread *td, int s)
{
        int error, optval;
        socklen_t size_val;

        size_val = sizeof(optval);
        error = kern_getsockopt(td, s, IPPROTO_IP, IP_HDRINCL,
            &optval, UIO_SYSSPACE, &size_val);
        if (error != 0)
                return (error);

        return (optval == 0);
}

/*
 * Updated sendto() when IP_HDRINCL is set:
 * tweak endian-dependent fields in the IP packet.
 */
static int
linux_sendto_hdrincl(struct thread *td, struct linux_sendto_args *linux_args)
{
/*
 * linux_ip_copysize defines how many bytes we should copy
 * from the beginning of the IP packet before we customize it for BSD.
 * It should include all the fields we modify (ip_len and ip_off).
 */
#define linux_ip_copysize       8

        struct ip *packet;
        struct msghdr msg;
        struct iovec aiov[1];
        int error;

        /* Check that the packet isn't too big or too small. */
        if (linux_args->len < linux_ip_copysize ||
            linux_args->len > IP_MAXPACKET)
                return (EINVAL);

        packet = (struct ip *)malloc(linux_args->len, M_LINUX, M_WAITOK);

        /* Make kernel copy of the packet to be sent */
        if ((error = copyin(PTRIN(linux_args->msg), packet,
            linux_args->len)))
                goto goout;

        /* Convert fields from Linux to BSD raw IP socket format */
        packet->ip_len = linux_args->len;
        packet->ip_off = ntohs(packet->ip_off);

        /* Prepare the msghdr and iovec structures describing the new packet */
        msg.msg_name = PTRIN(linux_args->to);
        msg.msg_namelen = linux_args->tolen;
        msg.msg_iov = aiov;
        msg.msg_iovlen = 1;
        msg.msg_control = NULL;
        msg.msg_flags = 0;
        aiov[0].iov_base = (char *)packet;
        aiov[0].iov_len = linux_args->len;
        error = linux_sendit(td, linux_args->s, &msg, linux_args->flags,
            NULL, UIO_SYSSPACE);
goout:
        free(packet, M_LINUX);
        return (error);
}

static const char *linux_netlink_names[] = {
        [LINUX_NETLINK_ROUTE] = "ROUTE",
        [LINUX_NETLINK_SOCK_DIAG] = "SOCK_DIAG",
        [LINUX_NETLINK_NFLOG] = "NFLOG",
        [LINUX_NETLINK_SELINUX] = "SELINUX",
        [LINUX_NETLINK_AUDIT] = "AUDIT",
        [LINUX_NETLINK_FIB_LOOKUP] = "FIB_LOOKUP",
        [LINUX_NETLINK_NETFILTER] = "NETFILTER",
        [LINUX_NETLINK_KOBJECT_UEVENT] = "KOBJECT_UEVENT",
};

int
linux_socket(struct thread *td, struct linux_socket_args *args)
{
        int retval_socket, type;
        sa_family_t domain;

        type = args->type & LINUX_SOCK_TYPE_MASK;
        if (type < 0 || type > LINUX_SOCK_MAX)
                return (EINVAL);
        retval_socket = linux_set_socket_flags(args->type & ~LINUX_SOCK_TYPE_MASK,
                &type);
        if (retval_socket != 0)
                return (retval_socket);
        domain = linux_to_bsd_domain(args->domain);
        if (domain == AF_UNKNOWN) {
                /* Mask off SOCK_NONBLOCK / CLOEXEC for error messages. */
                type = args->type & LINUX_SOCK_TYPE_MASK;
                if (args->domain == LINUX_AF_NETLINK &&
                    args->protocol == LINUX_NETLINK_AUDIT) {
                        ; /* Do nothing, quietly. */
                } else if (args->domain == LINUX_AF_NETLINK) {
                        const char *nl_name;

                        if (args->protocol >= 0 &&
                            args->protocol < nitems(linux_netlink_names))
                                nl_name = linux_netlink_names[args->protocol];
                        else
                                nl_name = NULL;
                        if (nl_name != NULL)
                                linux_msg(curthread,
                                    "unsupported socket(AF_NETLINK, %d, "
                                    "NETLINK_%s)", type, nl_name);
                        else
                                linux_msg(curthread,
                                    "unsupported socket(AF_NETLINK, %d, %d)",
                                    type, args->protocol);
                } else {
                        linux_msg(curthread, "unsupported socket domain %d, "
                            "type %d, protocol %d", args->domain, type,
                            args->protocol);
                }
                return (EAFNOSUPPORT);
        }

        retval_socket = kern_socket(td, domain, type, args->protocol);
        if (retval_socket)
                return (retval_socket);

        if (type == SOCK_RAW
            && (args->protocol == IPPROTO_RAW || args->protocol == 0)
            && domain == PF_INET) {
                /* It's a raw IP socket: set the IP_HDRINCL option. */
                int hdrincl;

                hdrincl = 1;
                /* We ignore any error returned by kern_setsockopt() */
                kern_setsockopt(td, td->td_retval[0], IPPROTO_IP, IP_HDRINCL,
                    &hdrincl, UIO_SYSSPACE, sizeof(hdrincl));
        }
#ifdef INET6
        /*
         * Linux AF_INET6 socket has IPV6_V6ONLY setsockopt set to 0 by default
         * and some apps depend on this. So, set V6ONLY to 0 for Linux apps.
         * For simplicity we do this unconditionally of the net.inet6.ip6.v6only
         * sysctl value.
         */
        if (domain == PF_INET6) {
                int v6only;

                v6only = 0;
                /* We ignore any error returned by setsockopt() */
                kern_setsockopt(td, td->td_retval[0], IPPROTO_IPV6, IPV6_V6ONLY,
                    &v6only, UIO_SYSSPACE, sizeof(v6only));
        }
#endif

        return (retval_socket);
}

int
linux_bind(struct thread *td, struct linux_bind_args *args)
{
        struct sockaddr *sa;
        int error;

        error = linux_to_bsd_sockaddr(PTRIN(args->name), &sa,
            &args->namelen);
        if (error != 0)
                return (error);

        error = kern_bindat(td, AT_FDCWD, args->s, sa);
        free(sa, M_SONAME);

        /* XXX */
        if (error == EADDRNOTAVAIL && args->namelen != sizeof(struct sockaddr_in))
                return (EINVAL);
        return (error);
}

int
linux_connect(struct thread *td, struct linux_connect_args *args)
{
        struct socket *so;
        struct sockaddr *sa;
        struct file *fp;
        int error;

        error = linux_to_bsd_sockaddr(PTRIN(args->name), &sa,
            &args->namelen);
        if (error != 0)
                return (error);

        error = kern_connectat(td, AT_FDCWD, args->s, sa);
        free(sa, M_SONAME);
        if (error != EISCONN)
                return (error);

        /*
         * Linux doesn't return EISCONN the first time it occurs,
         * when on a non-blocking socket. Instead it returns the
         * error getsockopt(SOL_SOCKET, SO_ERROR) would return on BSD.
         */
        error = getsock(td, args->s, &cap_connect_rights, &fp);
        if (error != 0)
                return (error);

        error = EISCONN;
        so = fp->f_data;
        if (atomic_load_int(&fp->f_flag) & FNONBLOCK) {
                SOCK_LOCK(so);
                if (so->so_emuldata == 0)
                        error = so->so_error;
                so->so_emuldata = (void *)1;
                SOCK_UNLOCK(so);
        }
        fdrop(fp, td);

        return (error);
}

int
linux_listen(struct thread *td, struct linux_listen_args *args)
{

        return (kern_listen(td, args->s, args->backlog));
}

static int
linux_accept_common(struct thread *td, int s, l_uintptr_t addr,
    l_uintptr_t namelen, int flags)
{
        struct sockaddr_storage ss = { .ss_len = sizeof(ss) };
        struct file *fp, *fp1;
        struct socket *so;
        socklen_t len;
        int bflags, error, error1;

        bflags = 0;
        fp = NULL;

        error = linux_set_socket_flags(flags, &bflags);
        if (error != 0)
                return (error);

        if (PTRIN(addr) != NULL) {
                error = copyin(PTRIN(namelen), &len, sizeof(len));
                if (error != 0)
                        return (error);
                if (len < 0)
                        return (EINVAL);
        } else
                len = 0;

        error = kern_accept4(td, s, (struct sockaddr *)&ss, bflags, &fp);

        /*
         * Translate errno values into ones used by Linux.
         */
        if (error != 0) {
                /*
                 * XXX. This is wrong, different sockaddr structures
                 * have different sizes.
                 */
                switch (error) {
                case EFAULT:
                        if (namelen != sizeof(struct sockaddr_in))
                                error = EINVAL;
                        break;
                case EINVAL:
                        error1 = getsock(td, s, &cap_accept_rights, &fp1);
                        if (error1 != 0) {
                                error = error1;
                                break;
                        }
                        so = fp1->f_data;
                        if (so->so_type == SOCK_DGRAM)
                                error = EOPNOTSUPP;
                        fdrop(fp1, td);
                        break;
                }
                return (error);
        }

        if (PTRIN(addr) != NULL) {
                len = min(ss.ss_len, len);
                error = linux_copyout_sockaddr((struct sockaddr *)&ss,
                    PTRIN(addr), len);
                if (error == 0) {
                        len = ss.ss_len;
                        error = copyout(&len, PTRIN(namelen), sizeof(len));
                }
                if (error != 0) {
                        fdclose(td, fp, td->td_retval[0]);
                        td->td_retval[0] = 0;
                }
        }
        if (fp != NULL)
                fdrop(fp, td);
        return (error);
}

int
linux_accept(struct thread *td, struct linux_accept_args *args)
{

        return (linux_accept_common(td, args->s, args->addr,
            args->namelen, 0));
}

int
linux_accept4(struct thread *td, struct linux_accept4_args *args)
{

        return (linux_accept_common(td, args->s, args->addr,
            args->namelen, args->flags));
}

int
linux_getsockname(struct thread *td, struct linux_getsockname_args *args)
{
        struct sockaddr_storage ss = { .ss_len = sizeof(ss) };
        socklen_t len;
        int error;

        error = copyin(PTRIN(args->namelen), &len, sizeof(len));
        if (error != 0)
                return (error);

        error = kern_getsockname(td, args->s, (struct sockaddr *)&ss);
        if (error != 0)
                return (error);

        len = min(ss.ss_len, len);
        error = linux_copyout_sockaddr((struct sockaddr *)&ss,
            PTRIN(args->addr), len);
        if (error == 0) {
                len = ss.ss_len;
                error = copyout(&len, PTRIN(args->namelen), sizeof(len));
        }
        return (error);
}

int
linux_getpeername(struct thread *td, struct linux_getpeername_args *args)
{
        struct sockaddr_storage ss = { .ss_len = sizeof(ss) };
        socklen_t len;
        int error;

        error = copyin(PTRIN(args->namelen), &len, sizeof(len));
        if (error != 0)
                return (error);

        error = kern_getpeername(td, args->s, (struct sockaddr *)&ss);
        if (error != 0)
                return (error);

        len = min(ss.ss_len, len);
        error = linux_copyout_sockaddr((struct sockaddr *)&ss,
            PTRIN(args->addr), len);
        if (error == 0) {
                len = ss.ss_len;
                error = copyout(&len, PTRIN(args->namelen), sizeof(len));
        }
        return (error);
}

int
linux_socketpair(struct thread *td, struct linux_socketpair_args *args)
{
        int domain, error, sv[2], type;

        domain = linux_to_bsd_domain(args->domain);
        if (domain != PF_LOCAL)
                return (EAFNOSUPPORT);
        type = args->type & LINUX_SOCK_TYPE_MASK;
        if (type < 0 || type > LINUX_SOCK_MAX)
                return (EINVAL);
        error = linux_set_socket_flags(args->type & ~LINUX_SOCK_TYPE_MASK,
            &type);
        if (error != 0)
                return (error);
        if (args->protocol != 0 && args->protocol != PF_UNIX) {
                /*
                 * Use of PF_UNIX as protocol argument is not right,
                 * but Linux does it.
                 * Do not map PF_UNIX as its Linux value is identical
                 * to FreeBSD one.
                 */
                return (EPROTONOSUPPORT);
        }
        error = kern_socketpair(td, domain, type, 0, sv);
        if (error != 0)
                return (error);
        error = copyout(sv, PTRIN(args->rsv), 2 * sizeof(int));
        if (error != 0) {
                (void)kern_close(td, sv[0]);
                (void)kern_close(td, sv[1]);
        }
        return (error);
}

#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
struct linux_send_args {
        register_t s;
        register_t msg;
        register_t len;
        register_t flags;
};

static int
linux_send(struct thread *td, struct linux_send_args *args)
{
        struct sendto_args /* {
                int s;
                caddr_t buf;
                int len;
                int flags;
                caddr_t to;
                int tolen;
        } */ bsd_args;
        struct file *fp;
        int error;

        bsd_args.s = args->s;
        bsd_args.buf = (caddr_t)PTRIN(args->msg);
        bsd_args.len = args->len;
        bsd_args.flags = linux_to_bsd_msg_flags(args->flags);
        bsd_args.to = NULL;
        bsd_args.tolen = 0;
        error = sys_sendto(td, &bsd_args);
        if (error == ENOTCONN) {
                /*
                 * Linux doesn't return ENOTCONN for non-blocking sockets.
                 * Instead it returns the EAGAIN.
                 */
                error = getsock(td, args->s, &cap_send_rights, &fp);
                if (error == 0) {
                        if (atomic_load_int(&fp->f_flag) & FNONBLOCK)
                                error = EAGAIN;
                        fdrop(fp, td);
                }
        }
        return (error);
}

struct linux_recv_args {
        register_t s;
        register_t msg;
        register_t len;
        register_t flags;
};

static int
linux_recv(struct thread *td, struct linux_recv_args *args)
{
        struct recvfrom_args /* {
                int s;
                caddr_t buf;
                int len;
                int flags;
                struct sockaddr *from;
                socklen_t fromlenaddr;
        } */ bsd_args;

        bsd_args.s = args->s;
        bsd_args.buf = (caddr_t)PTRIN(args->msg);
        bsd_args.len = args->len;
        bsd_args.flags = linux_to_bsd_msg_flags(args->flags);
        bsd_args.from = NULL;
        bsd_args.fromlenaddr = 0;
        return (sys_recvfrom(td, &bsd_args));
}
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */

int
linux_sendto(struct thread *td, struct linux_sendto_args *args)
{
        struct msghdr msg;
        struct iovec aiov;
        struct socket *so;
        struct file *fp;
        int error;

        if (linux_check_hdrincl(td, args->s) == 0)
                /* IP_HDRINCL set, tweak the packet before sending */
                return (linux_sendto_hdrincl(td, args));

        bzero(&msg, sizeof(msg));
        error = getsock(td, args->s, &cap_send_connect_rights, &fp);
        if (error != 0)
                return (error);
        so = fp->f_data;
        if ((so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0) {
                msg.msg_name = PTRIN(args->to);
                msg.msg_namelen = args->tolen;
        }
        msg.msg_iov = &aiov;
        msg.msg_iovlen = 1;
        aiov.iov_base = PTRIN(args->msg);
        aiov.iov_len = args->len;
        fdrop(fp, td);
        return (linux_sendit(td, args->s, &msg, args->flags, NULL,
            UIO_USERSPACE));
}

int
linux_recvfrom(struct thread *td, struct linux_recvfrom_args *args)
{
        struct sockaddr *sa;
        struct msghdr msg;
        struct iovec aiov;
        int error, fromlen;

        if (PTRIN(args->fromlen) != NULL) {
                error = copyin(PTRIN(args->fromlen), &fromlen,
                    sizeof(fromlen));
                if (error != 0)
                        return (error);
                if (fromlen < 0)
                        return (EINVAL);
                fromlen = min(fromlen, SOCK_MAXADDRLEN);
                sa = malloc(fromlen, M_SONAME, M_WAITOK);
        } else {
                fromlen = 0;
                sa = NULL;
        }

        msg.msg_name = sa;
        msg.msg_namelen = fromlen;
        msg.msg_iov = &aiov;
        msg.msg_iovlen = 1;
        aiov.iov_base = PTRIN(args->buf);
        aiov.iov_len = args->len;
        msg.msg_control = 0;
        msg.msg_flags = linux_to_bsd_msg_flags(args->flags);

        error = kern_recvit(td, args->s, &msg, UIO_SYSSPACE, NULL);
        if (error != 0)
                goto out;

        /*
         * XXX. Seems that FreeBSD is different from Linux here. Linux
         * fill source address if underlying protocol provides it, while
         * FreeBSD fill it if underlying protocol is not connection-oriented.
         * So, kern_recvit() set msg.msg_namelen to 0 if protocol pr_flags
         * does not contains PR_ADDR flag.
         */
        if (PTRIN(args->from) != NULL && msg.msg_namelen != 0)
                error = linux_copyout_sockaddr(sa, PTRIN(args->from),
                    msg.msg_namelen);

        if (error == 0 && PTRIN(args->fromlen) != NULL)
                error = copyout(&msg.msg_namelen, PTRIN(args->fromlen),
                    sizeof(msg.msg_namelen));
out:
        free(sa, M_SONAME);
        return (error);
}

static int
linux_sendmsg_common(struct thread *td, l_int s, struct l_msghdr *msghdr,
    l_uint flags)
{
        struct sockaddr_storage ss = { .ss_len = sizeof(ss) };
        struct cmsghdr *cmsg;
        struct mbuf *control;
        struct msghdr msg;
        struct l_cmsghdr linux_cmsg;
        struct l_cmsghdr *ptr_cmsg;
        struct l_msghdr linux_msghdr;
        struct iovec *iov;
        socklen_t datalen;
        struct socket *so;
        sa_family_t sa_family;
        struct file *fp;
        void *data;
        l_size_t len;
        l_size_t clen;
        int error;

        error = copyin(msghdr, &linux_msghdr, sizeof(linux_msghdr));
        if (error != 0)
                return (error);

        /*
         * Some Linux applications (ping) define a non-NULL control data
         * pointer, but a msg_controllen of 0, which is not allowed in the
         * FreeBSD system call interface.  NULL the msg_control pointer in
         * order to handle this case.  This should be checked, but allows the
         * Linux ping to work.
         */
        if (PTRIN(linux_msghdr.msg_control) != NULL &&
            linux_msghdr.msg_controllen == 0)
                linux_msghdr.msg_control = PTROUT(NULL);

        error = linux_to_bsd_msghdr(&msg, &linux_msghdr);
        if (error != 0)
                return (error);

#ifdef COMPAT_LINUX32
        error = freebsd32_copyiniov(PTRIN(msg.msg_iov), msg.msg_iovlen,
            &iov, EMSGSIZE);
#else
        error = copyiniov(msg.msg_iov, msg.msg_iovlen, &iov, EMSGSIZE);
#endif
        if (error != 0)
                return (error);

        control = NULL;

        error = kern_getsockname(td, s, (struct sockaddr *)&ss);
        if (error != 0)
                goto bad;
        sa_family = ss.ss_family;

        if (flags & LINUX_MSG_OOB) {
                error = EOPNOTSUPP;
                if (sa_family == AF_UNIX)
                        goto bad;

                error = getsock(td, s, &cap_send_rights, &fp);
                if (error != 0)
                        goto bad;
                so = fp->f_data;
                if (so->so_type != SOCK_STREAM)
                        error = EOPNOTSUPP;
                fdrop(fp, td);
                if (error != 0)
                        goto bad;
        }

        if (linux_msghdr.msg_controllen >= sizeof(struct l_cmsghdr)) {
                error = ENOBUFS;
                control = m_get(M_WAITOK, MT_CONTROL);
                MCLGET(control, M_WAITOK);
                data = mtod(control, void *);
                datalen = 0;

                ptr_cmsg = PTRIN(linux_msghdr.msg_control);
                clen = linux_msghdr.msg_controllen;
                do {
                        error = copyin(ptr_cmsg, &linux_cmsg,
                            sizeof(struct l_cmsghdr));
                        if (error != 0)
                                goto bad;

                        error = EINVAL;
                        if (linux_cmsg.cmsg_len < sizeof(struct l_cmsghdr) ||
                            linux_cmsg.cmsg_len > clen)
                                goto bad;

                        if (datalen + CMSG_HDRSZ > MCLBYTES)
                                goto bad;

                        /*
                         * Now we support only SCM_RIGHTS and SCM_CRED,
                         * so return EINVAL in any other cmsg_type
                         */
                        cmsg = data;
                        cmsg->cmsg_type =
                            linux_to_bsd_cmsg_type(linux_cmsg.cmsg_type);
                        cmsg->cmsg_level =
                            linux_to_bsd_sockopt_level(linux_cmsg.cmsg_level);
                        if (cmsg->cmsg_type == -1
                            || cmsg->cmsg_level != SOL_SOCKET) {
                                linux_msg(curthread,
                                    "unsupported sendmsg cmsg level %d type %d",
                                    linux_cmsg.cmsg_level, linux_cmsg.cmsg_type);
                                goto bad;
                        }

                        /*
                         * Some applications (e.g. pulseaudio) attempt to
                         * send ancillary data even if the underlying protocol
                         * doesn't support it which is not allowed in the
                         * FreeBSD system call interface.
                         */
                        if (sa_family != AF_UNIX)
                                goto next;

                        if (cmsg->cmsg_type == SCM_CREDS) {
                                len = sizeof(struct cmsgcred);
                                if (datalen + CMSG_SPACE(len) > MCLBYTES)
                                        goto bad;

                                /*
                                 * The lower levels will fill in the structure
                                 */
                                memset(CMSG_DATA(data), 0, len);
                        } else {
                                len = linux_cmsg.cmsg_len - L_CMSG_HDRSZ;
                                if (datalen + CMSG_SPACE(len) < datalen ||
                                    datalen + CMSG_SPACE(len) > MCLBYTES)
                                        goto bad;

                                error = copyin(LINUX_CMSG_DATA(ptr_cmsg),
                                    CMSG_DATA(data), len);
                                if (error != 0)
                                        goto bad;
                        }

                        cmsg->cmsg_len = CMSG_LEN(len);
                        data = (char *)data + CMSG_SPACE(len);
                        datalen += CMSG_SPACE(len);

next:
                        if (clen <= LINUX_CMSG_ALIGN(linux_cmsg.cmsg_len))
                                break;

                        clen -= LINUX_CMSG_ALIGN(linux_cmsg.cmsg_len);
                        ptr_cmsg = (struct l_cmsghdr *)((char *)ptr_cmsg +
                            LINUX_CMSG_ALIGN(linux_cmsg.cmsg_len));
                } while(clen >= sizeof(struct l_cmsghdr));

                control->m_len = datalen;
                if (datalen == 0) {
                        m_freem(control);
                        control = NULL;
                }
        }

        msg.msg_iov = iov;
        msg.msg_flags = 0;
        error = linux_sendit(td, s, &msg, flags, control, UIO_USERSPACE);
        control = NULL;

bad:
        m_freem(control);
        free(iov, M_IOV);
        return (error);
}

int
linux_sendmsg(struct thread *td, struct linux_sendmsg_args *args)
{

        return (linux_sendmsg_common(td, args->s, PTRIN(args->msg),
            args->flags));
}

int
linux_sendmmsg(struct thread *td, struct linux_sendmmsg_args *args)
{
        struct l_mmsghdr *msg;
        l_uint retval;
        int error, datagrams;

        if (args->vlen > UIO_MAXIOV)
                args->vlen = UIO_MAXIOV;

        msg = PTRIN(args->msg);
        datagrams = 0;
        while (datagrams < args->vlen) {
                error = linux_sendmsg_common(td, args->s, &msg->msg_hdr,
                    args->flags);
                if (error != 0)
                        break;

                retval = td->td_retval[0];
                error = copyout(&retval, &msg->msg_len, sizeof(msg->msg_len));
                if (error != 0)
                        break;
                ++msg;
                ++datagrams;
        }
        if (error == 0)
                td->td_retval[0] = datagrams;
        return (error);
}

static int
recvmsg_scm_rights(struct thread *td, l_uint flags, socklen_t *datalen,
    void **data, void **udata)
{
        int i, fd, fds, *fdp;

        if (flags & LINUX_MSG_CMSG_CLOEXEC) {
                fds = *datalen / sizeof(int);
                fdp = *data;
                for (i = 0; i < fds; i++) {
                        fd = *fdp++;
                        (void)kern_fcntl(td, fd, F_SETFD, FD_CLOEXEC);
                }
        }
        return (0);
}


static int
recvmsg_scm_creds(socklen_t *datalen, void **data, void **udata)
{
        struct cmsgcred *cmcred;
        struct l_ucred lu;

        cmcred = *data;
        lu.pid = cmcred->cmcred_pid;
        lu.uid = cmcred->cmcred_uid;
        lu.gid = cmcred->cmcred_gid;
        memmove(*data, &lu, sizeof(lu));
        *datalen = sizeof(lu);
        return (0);
}
_Static_assert(sizeof(struct cmsgcred) >= sizeof(struct l_ucred),
    "scm_creds sizeof l_ucred");

static int
recvmsg_scm_creds2(socklen_t *datalen, void **data, void **udata)
{
        struct sockcred2 *scred;
        struct l_ucred lu;

        scred = *data;
        lu.pid = scred->sc_pid;
        lu.uid = scred->sc_uid;
        lu.gid = scred->sc_gid;
        memmove(*data, &lu, sizeof(lu));
        *datalen = sizeof(lu);
        return (0);
}
_Static_assert(sizeof(struct sockcred2) >= sizeof(struct l_ucred),
    "scm_creds2 sizeof l_ucred");

#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
static int
recvmsg_scm_timestamp(l_int msg_type, socklen_t *datalen, void **data,
    void **udata)
{
        l_sock_timeval ltv64;
        l_timeval ltv;
        struct timeval *tv;
        socklen_t len;
        void *buf;

        if (*datalen != sizeof(struct timeval))
                return (EMSGSIZE);

        tv = *data;
#if defined(COMPAT_LINUX32)
        if (msg_type == LINUX_SCM_TIMESTAMPO &&
            (tv->tv_sec > INT_MAX || tv->tv_sec < INT_MIN))
                return (EOVERFLOW);
#endif
        if (msg_type == LINUX_SCM_TIMESTAMPN)
                len = sizeof(ltv64);
        else
                len = sizeof(ltv);

        buf = malloc(len, M_LINUX, M_WAITOK);
        if (msg_type == LINUX_SCM_TIMESTAMPN) {
                ltv64.tv_sec = tv->tv_sec;
                ltv64.tv_usec = tv->tv_usec;
                memmove(buf, &ltv64, len);
        } else {
                ltv.tv_sec = tv->tv_sec;
                ltv.tv_usec = tv->tv_usec;
                memmove(buf, &ltv, len);
        }
        *data = *udata = buf;
        *datalen = len;
        return (0);
}
#else
_Static_assert(sizeof(struct timeval) == sizeof(l_timeval),
    "scm_timestamp sizeof l_timeval");
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */

#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
static int
recvmsg_scm_timestampns(l_int msg_type, socklen_t *datalen, void **data,
    void **udata)
{
        struct l_timespec64 ts64;
        struct l_timespec ts32;
        struct timespec ts;
        socklen_t len;
        void *buf;

        if (msg_type == LINUX_SCM_TIMESTAMPNSO)
                len = sizeof(ts32);
        else
                len = sizeof(ts64);

        buf = malloc(len, M_LINUX, M_WAITOK);
        bintime2timespec(*data, &ts);
        if (msg_type == LINUX_SCM_TIMESTAMPNSO) {
                ts32.tv_sec = ts.tv_sec;
                ts32.tv_nsec = ts.tv_nsec;
                memmove(buf, &ts32, len);
        } else {
                ts64.tv_sec = ts.tv_sec;
                ts64.tv_nsec = ts.tv_nsec;
                memmove(buf, &ts64, len);
        }
        *data = *udata = buf;
        *datalen = len;
        return (0);
}
#else
static int
recvmsg_scm_timestampns(l_int msg_type, socklen_t *datalen, void **data,
    void **udata)
{
        struct timespec ts;

        bintime2timespec(*data, &ts);
        memmove(*data, &ts, sizeof(struct timespec));
        *datalen = sizeof(struct timespec);
        return (0);
}
_Static_assert(sizeof(struct bintime) >= sizeof(struct timespec),
    "scm_timestampns sizeof timespec");
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */

static int
recvmsg_scm_sol_socket(struct thread *td, l_int msg_type, l_int lmsg_type,
    l_uint flags, socklen_t *datalen, void **data, void **udata)
{
        int error;

        error = 0;
        switch (msg_type) {
        case SCM_RIGHTS:
                error = recvmsg_scm_rights(td, flags, datalen,
                    data, udata);
                break;
        case SCM_CREDS:
                error = recvmsg_scm_creds(datalen, data, udata);
                break;
        case SCM_CREDS2:
                error = recvmsg_scm_creds2(datalen, data, udata);
                break;
        case SCM_TIMESTAMP:
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
                error = recvmsg_scm_timestamp(lmsg_type, datalen,
                    data, udata);
#endif
                break;
        case SCM_BINTIME:
                error = recvmsg_scm_timestampns(lmsg_type, datalen,
                    data, udata);
                break;
        }

        return (error);
}

static int
recvmsg_scm_ip_origdstaddr(socklen_t *datalen, void **data, void **udata)
{
        struct l_sockaddr *lsa;
        int error;

        error = bsd_to_linux_sockaddr(*data, &lsa, *datalen);
        if (error == 0) {
                *data = *udata = lsa;
                *datalen = sizeof(*lsa);
        }
        return (error);
}

static int
recvmsg_scm_ipproto_ip(l_int msg_type, l_int lmsg_type, socklen_t *datalen,
    void **data, void **udata)
{
        int error;

        error = 0;
        switch (msg_type) {
        case IP_ORIGDSTADDR:
                error = recvmsg_scm_ip_origdstaddr(datalen, data,
                    udata);
                break;
        }

        return (error);
}

static int
linux_recvmsg_common(struct thread *td, l_int s, struct l_msghdr *msghdr,
    l_uint flags, struct msghdr *msg)
{
        struct proc *p = td->td_proc;
        struct cmsghdr *cm;
        struct l_cmsghdr *lcm = NULL;
        socklen_t datalen, maxlen, outlen;
        struct l_msghdr l_msghdr;
        struct iovec *iov, *uiov;
        struct mbuf *m, *control = NULL;
        struct mbuf **controlp;
        struct sockaddr *sa;
        caddr_t outbuf;
        void *data, *udata;
        int error, skiped;

        error = copyin(msghdr, &l_msghdr, sizeof(l_msghdr));
        if (error != 0)
                return (error);

        /*
         * Pass user-supplied recvmsg() flags in msg_flags field,
         * following sys_recvmsg() convention.
        */
        l_msghdr.msg_flags = flags;

        error = linux_to_bsd_msghdr(msg, &l_msghdr);
        if (error != 0)
                return (error);

#ifdef COMPAT_LINUX32
        error = freebsd32_copyiniov(PTRIN(msg->msg_iov), msg->msg_iovlen,
            &iov, EMSGSIZE);
#else
        error = copyiniov(msg->msg_iov, msg->msg_iovlen, &iov, EMSGSIZE);
#endif
        if (error != 0)
                return (error);

        if (msg->msg_name != NULL && msg->msg_namelen > 0) {
                msg->msg_namelen = min(msg->msg_namelen, SOCK_MAXADDRLEN);
                sa = malloc(msg->msg_namelen, M_SONAME, M_WAITOK);
                msg->msg_name = sa;
        } else {
                sa = NULL;
                msg->msg_name = NULL;
        }

        uiov = msg->msg_iov;
        msg->msg_iov = iov;
        controlp = (msg->msg_control != NULL) ? &control : NULL;
        error = kern_recvit(td, s, msg, UIO_SYSSPACE, controlp);
        msg->msg_iov = uiov;
        if (error != 0)
                goto bad;

        /*
         * Note that kern_recvit() updates msg->msg_namelen.
         */
        if (msg->msg_name != NULL && msg->msg_namelen > 0) {
                msg->msg_name = PTRIN(l_msghdr.msg_name);
                error = linux_copyout_sockaddr(sa, msg->msg_name,
                    msg->msg_namelen);
                if (error != 0)
                        goto bad;
        }

        error = bsd_to_linux_msghdr(msg, &l_msghdr);
        if (error != 0)
                goto bad;

        skiped = outlen = 0;
        maxlen = l_msghdr.msg_controllen;
        if (control == NULL)
                goto out;

        lcm = malloc(L_CMSG_HDRSZ, M_LINUX, M_WAITOK | M_ZERO);
        msg->msg_control = mtod(control, struct cmsghdr *);
        msg->msg_controllen = control->m_len;
        outbuf = PTRIN(l_msghdr.msg_control);
        for (m = control; m != NULL; m = m->m_next) {
                cm = mtod(m, struct cmsghdr *);
                lcm->cmsg_type = bsd_to_linux_cmsg_type(p, cm->cmsg_type,
                    cm->cmsg_level);
                lcm->cmsg_level = bsd_to_linux_sockopt_level(cm->cmsg_level);

                if (lcm->cmsg_type == -1 ||
                    lcm->cmsg_level == -1) {
                        LINUX_RATELIMIT_MSG_OPT2(
                            "unsupported recvmsg cmsg level %d type %d",
                            cm->cmsg_level, cm->cmsg_type);
                        /* Skip unsupported messages */
                        skiped++;
                        continue;
                }
                data = CMSG_DATA(cm);
                datalen = (caddr_t)cm + cm->cmsg_len - (caddr_t)data;
                udata = NULL;
                error = 0;

                switch (cm->cmsg_level) {
                case IPPROTO_IP:
                        error = recvmsg_scm_ipproto_ip(cm->cmsg_type,
                            lcm->cmsg_type, &datalen, &data, &udata);
                        break;
                case SOL_SOCKET:
                        error = recvmsg_scm_sol_socket(td, cm->cmsg_type,
                            lcm->cmsg_type, flags, &datalen, &data, &udata);
                        break;
                }

                /* The recvmsg_scm_ is responsible to free udata on error. */
                if (error != 0)
                        goto bad;

                if (outlen + LINUX_CMSG_LEN(datalen) > maxlen) {
                        if (outlen == 0) {
                                error = EMSGSIZE;
                                goto err;
                        } else {
                                l_msghdr.msg_flags |= LINUX_MSG_CTRUNC;
                                m_dispose_extcontrolm(control);
                                free(udata, M_LINUX);
                                goto out;
                        }
                }

                lcm->cmsg_len = LINUX_CMSG_LEN(datalen);
                error = copyout(lcm, outbuf, L_CMSG_HDRSZ);
                if (error == 0) {
                        error = copyout(data, LINUX_CMSG_DATA(outbuf), datalen);
                        if (error == 0) {
                                outbuf += LINUX_CMSG_SPACE(datalen);
                                outlen += LINUX_CMSG_SPACE(datalen);
                        }
                }
err:
                free(udata, M_LINUX);
                if (error != 0)
                        goto bad;
        }
        if (outlen == 0 && skiped > 0) {
                error = EINVAL;
                goto bad;
        }

out:
        l_msghdr.msg_controllen = outlen;
        error = copyout(&l_msghdr, msghdr, sizeof(l_msghdr));

bad:
        if (control != NULL) {
                if (error != 0)
                        m_dispose_extcontrolm(control);
                m_freem(control);
        }
        free(iov, M_IOV);
        free(lcm, M_LINUX);
        free(sa, M_SONAME);

        return (error);
}

int
linux_recvmsg(struct thread *td, struct linux_recvmsg_args *args)
{
        struct msghdr bsd_msg;
        struct file *fp;
        int error;

        error = getsock(td, args->s, &cap_recv_rights, &fp);
        if (error != 0)
                return (error);
        fdrop(fp, td);
        return (linux_recvmsg_common(td, args->s, PTRIN(args->msg),
            args->flags, &bsd_msg));
}

static int
linux_recvmmsg_common(struct thread *td, l_int s, struct l_mmsghdr *msg,
    l_uint vlen, l_uint flags, struct timespec *tts)
{
        struct msghdr bsd_msg;
        struct timespec ts;
        struct file *fp;
        l_uint retval;
        int error, datagrams;

        error = getsock(td, s, &cap_recv_rights, &fp);
        if (error != 0)
                return (error);
        datagrams = 0;
        while (datagrams < vlen) {
                error = linux_recvmsg_common(td, s, &msg->msg_hdr,
                    flags & ~LINUX_MSG_WAITFORONE, &bsd_msg);
                if (error != 0)
                        break;

                retval = td->td_retval[0];
                error = copyout(&retval, &msg->msg_len, sizeof(msg->msg_len));
                if (error != 0)
                        break;
                ++msg;
                ++datagrams;

                /*
                 * MSG_WAITFORONE turns on MSG_DONTWAIT after one packet.
                 */
                if (flags & LINUX_MSG_WAITFORONE)
                        flags |= LINUX_MSG_DONTWAIT;

                /*
                 * See BUGS section of recvmmsg(2).
                 */
                if (tts) {
                        getnanotime(&ts);
                        timespecsub(&ts, tts, &ts);
                        if (!timespecisset(&ts) || ts.tv_sec > 0)
                                break;
                }
                /* Out of band data, return right away. */
                if (bsd_msg.msg_flags & MSG_OOB)
                        break;
        }
        if (error == 0)
                td->td_retval[0] = datagrams;
        fdrop(fp, td);
        return (error);
}

int
linux_recvmmsg(struct thread *td, struct linux_recvmmsg_args *args)
{
        struct timespec ts, tts, *ptts;
        int error;

        if (args->timeout) {
                error = linux_get_timespec(&ts, args->timeout);
                if (error != 0)
                        return (error);
                getnanotime(&tts);
                timespecadd(&tts, &ts, &tts);
                ptts = &tts;
        }
                else ptts = NULL;

        return (linux_recvmmsg_common(td, args->s, PTRIN(args->msg),
            args->vlen, args->flags, ptts));
}

#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
int
linux_recvmmsg_time64(struct thread *td, struct linux_recvmmsg_time64_args *args)
{
        struct timespec ts, tts, *ptts;
        int error;

        if (args->timeout) {
                error = linux_get_timespec64(&ts, args->timeout);
                if (error != 0)
                        return (error);
                getnanotime(&tts);
                timespecadd(&tts, &ts, &tts);
                ptts = &tts;
        }
                else ptts = NULL;

        return (linux_recvmmsg_common(td, args->s, PTRIN(args->msg),
            args->vlen, args->flags, ptts));
}
#endif

int
linux_shutdown(struct thread *td, struct linux_shutdown_args *args)
{

        return (kern_shutdown(td, args->s, args->how));
}

int
linux_setsockopt(struct thread *td, struct linux_setsockopt_args *args)
{
        struct proc *p = td->td_proc;
        struct linux_pemuldata *pem;
        l_timeval linux_tv;
        l_uint linux_timeout;
        struct sockaddr *sa;
        struct timeval tv;
        u_int bsd_timeout;
        socklen_t len;
        int error, level, name, val;

        level = linux_to_bsd_sockopt_level(args->level);
        switch (level) {
        case SOL_SOCKET:
                name = linux_to_bsd_so_sockopt(args->optname);
                switch (name) {
                case LOCAL_CREDS_PERSISTENT:
                        level = SOL_LOCAL;
                        break;
                case SO_RCVTIMEO:
                        /* FALLTHROUGH */
                case SO_SNDTIMEO:
                        error = copyin(PTRIN(args->optval), &linux_tv,
                            sizeof(linux_tv));
                        if (error != 0)
                                return (error);
                        tv.tv_sec = linux_tv.tv_sec;
                        tv.tv_usec = linux_tv.tv_usec;
                        return (kern_setsockopt(td, args->s, level,
                            name, &tv, UIO_SYSSPACE, sizeof(tv)));
                        /* NOTREACHED */
                case SO_TIMESTAMP:
                        /* overwrite SO_BINTIME */
                        val = 0;
                        error = kern_setsockopt(td, args->s, level,
                            SO_BINTIME, &val, UIO_SYSSPACE, sizeof(val));
                        if (error != 0)
                                return (error);
                        pem = pem_find(p);
                        pem->so_timestamp = args->optname;
                        break;
                case SO_BINTIME:
                        /* overwrite SO_TIMESTAMP */
                        val = 0;
                        error = kern_setsockopt(td, args->s, level,
                            SO_TIMESTAMP, &val, UIO_SYSSPACE, sizeof(val));
                        if (error != 0)
                                return (error);
                        pem = pem_find(p);
                        pem->so_timestampns = args->optname;
                        break;
                default:
                        break;
                }
                break;
        case IPPROTO_IP:
                if (args->optname == LINUX_IP_RECVERR &&
                    linux_ignore_ip_recverr) {
                        /*
                         * XXX: This is a hack to unbreak DNS resolution
                         *      with glibc 2.30 and above.
                         */
                        return (0);
                }
                name = linux_to_bsd_ip_sockopt(args->optname);
                break;
        case IPPROTO_IPV6:
                if (args->optname == LINUX_IPV6_RECVERR &&
                    linux_ignore_ip_recverr) {
                        /*
                         * XXX: This is a hack to unbreak DNS resolution
                         *      with glibc 2.30 and above.
                         */
                        return (0);
                }
                name = linux_to_bsd_ip6_sockopt(args->optname);
                break;
        case IPPROTO_TCP:
                name = linux_to_bsd_tcp_sockopt(args->optname);
                switch (name) {
                case TCP_MAXUNACKTIME:
                        if (args->optlen < sizeof(linux_timeout))
                                return (EINVAL);

                        error = copyin(PTRIN(args->optval), &linux_timeout,
                            sizeof(linux_timeout));
                        if (error != 0)
                                return (error);

                        bsd_timeout = linux_to_bsd_tcp_user_timeout(
                            linux_timeout);
                        return (kern_setsockopt(td, args->s, level, name,
                            &bsd_timeout, UIO_SYSSPACE,
                            sizeof(bsd_timeout)));
                default:
                        break;
                }
                break;
        case SOL_NETLINK:
                name = args->optname;
                break;
        default:
                name = -1;
                break;
        }
        if (name < 0) {
                if (name == -1)
                        linux_msg(curthread,
                            "unsupported setsockopt level %d optname %d",
                            args->level, args->optname);
                return (ENOPROTOOPT);
        }

        switch (name) {
        case IPV6_NEXTHOP: {
                len = args->optlen;
                error = linux_to_bsd_sockaddr(PTRIN(args->optval), &sa, &len);
                if (error != 0)
                        return (error);

                error = kern_setsockopt(td, args->s, level,
                    name, sa, UIO_SYSSPACE, len);
                free(sa, M_SONAME);
                break;
        }
        case MCAST_JOIN_GROUP:
        case MCAST_LEAVE_GROUP:
        case MCAST_JOIN_SOURCE_GROUP:
        case MCAST_LEAVE_SOURCE_GROUP: {
                struct group_source_req req;
                size_t size;

                size = (name == MCAST_JOIN_SOURCE_GROUP ||
                    name == MCAST_LEAVE_SOURCE_GROUP) ?
                    sizeof(struct group_source_req) : sizeof(struct group_req);

                if ((error = copyin(PTRIN(args->optval), &req, size)))
                        return (error);
                len = sizeof(struct sockaddr_storage);
                if ((error = linux_to_bsd_sockaddr(
                    (struct l_sockaddr *)&req.gsr_group, NULL, &len)))
                        return (error);
                if (size == sizeof(struct group_source_req) &&
                    (error = linux_to_bsd_sockaddr(
                    (struct l_sockaddr *)&req.gsr_source, NULL, &len)))
                        return (error);
                error = kern_setsockopt(td, args->s, level, name, &req,
                    UIO_SYSSPACE, size);
                break;
        }
        default:
                error = kern_setsockopt(td, args->s, level,
                    name, PTRIN(args->optval), UIO_USERSPACE, args->optlen);
        }

        return (error);
}

static int
linux_sockopt_copyout(struct thread *td, void *val, socklen_t len,
    struct linux_getsockopt_args *args)
{
        int error;

        error = copyout(val, PTRIN(args->optval), len);
        if (error == 0)
                error = copyout(&len, PTRIN(args->optlen), sizeof(len));
        return (error);
}

static int
linux_getsockopt_so_peergroups(struct thread *td,
    struct linux_getsockopt_args *args)
{
        l_gid_t *out = PTRIN(args->optval);
        struct xucred xu;
        socklen_t xulen, len;
        int error, i;

        xulen = sizeof(xu);
        error = kern_getsockopt(td, args->s, 0,
            LOCAL_PEERCRED, &xu, UIO_SYSSPACE, &xulen);
        if (error != 0)
                return (error);

        len = xu.cr_ngroups * sizeof(l_gid_t);
        if (args->optlen < len) {
                error = copyout(&len, PTRIN(args->optlen), sizeof(len));
                if (error == 0)
                        error = ERANGE;
                return (error);
        }

        /* "- 1" to skip the primary group. */
        for (i = 0; i < xu.cr_ngroups - 1; i++) {
                /* Copy to cope with a possible type discrepancy. */
                const l_gid_t g = xu.cr_groups[i + 1];

                error = copyout(&g, out + i, sizeof(l_gid_t));
                if (error != 0)
                        return (error);
        }

        error = copyout(&len, PTRIN(args->optlen), sizeof(len));
        return (error);
}

static int
linux_getsockopt_so_peersec(struct thread *td,
    struct linux_getsockopt_args *args)
{
        socklen_t len;
        int error;

        len = sizeof(SECURITY_CONTEXT_STRING);
        if (args->optlen < len) {
                error = copyout(&len, PTRIN(args->optlen), sizeof(len));
                if (error == 0)
                        error = ERANGE;
                return (error);
        }

        return (linux_sockopt_copyout(td, SECURITY_CONTEXT_STRING,
            len, args));
}

static int
linux_getsockopt_so_linger(struct thread *td,
    struct linux_getsockopt_args *args)
{
        struct linger ling;
        socklen_t len;
        int error;

        len = sizeof(ling);
        error = kern_getsockopt(td, args->s, SOL_SOCKET,
            SO_LINGER, &ling, UIO_SYSSPACE, &len);
        if (error != 0)
                return (error);
        ling.l_onoff = ((ling.l_onoff & SO_LINGER) != 0);
        return (linux_sockopt_copyout(td, &ling, len, args));
}

int
linux_getsockopt(struct thread *td, struct linux_getsockopt_args *args)
{
        l_uint linux_timeout;
        l_timeval linux_tv;
        struct timeval tv;
        socklen_t tv_len, xulen, len;
        struct sockaddr *sa;
        u_int bsd_timeout;
        struct xucred xu;
        struct l_ucred lxu;
        int error, level, name, newval;

        level = linux_to_bsd_sockopt_level(args->level);
        switch (level) {
        case SOL_SOCKET:
                switch (args->optname) {
                case LINUX_SO_PEERGROUPS:
                        return (linux_getsockopt_so_peergroups(td, args));
                case LINUX_SO_PEERSEC:
                        return (linux_getsockopt_so_peersec(td, args));
                default:
                        break;
                }

                name = linux_to_bsd_so_sockopt(args->optname);
                switch (name) {
                case LOCAL_CREDS_PERSISTENT:
                        level = SOL_LOCAL;
                        break;
                case SO_RCVTIMEO:
                        /* FALLTHROUGH */
                case SO_SNDTIMEO:
                        tv_len = sizeof(tv);
                        error = kern_getsockopt(td, args->s, level,
                            name, &tv, UIO_SYSSPACE, &tv_len);
                        if (error != 0)
                                return (error);
                        linux_tv.tv_sec = tv.tv_sec;
                        linux_tv.tv_usec = tv.tv_usec;
                        return (linux_sockopt_copyout(td, &linux_tv,
                            sizeof(linux_tv), args));
                        /* NOTREACHED */
                case LOCAL_PEERCRED:
                        if (args->optlen < sizeof(lxu))
                                return (EINVAL);
                        /*
                         * LOCAL_PEERCRED is not served at the SOL_SOCKET level,
                         * but by the Unix socket's level 0.
                         */
                        level = 0;
                        xulen = sizeof(xu);
                        error = kern_getsockopt(td, args->s, level,
                            name, &xu, UIO_SYSSPACE, &xulen);
                        if (error != 0)
                                return (error);
                        lxu.pid = xu.cr_pid;
                        lxu.uid = xu.cr_uid;
                        lxu.gid = xu.cr_gid;
                        return (linux_sockopt_copyout(td, &lxu,
                            sizeof(lxu), args));
                        /* NOTREACHED */
                case SO_ERROR:
                        len = sizeof(newval);
                        error = kern_getsockopt(td, args->s, level,
                            name, &newval, UIO_SYSSPACE, &len);
                        if (error != 0)
                                return (error);
                        newval = -bsd_to_linux_errno(newval);
                        return (linux_sockopt_copyout(td, &newval,
                            len, args));
                        /* NOTREACHED */
                case SO_DOMAIN:
                        len = sizeof(newval);
                        error = kern_getsockopt(td, args->s, level,
                            name, &newval, UIO_SYSSPACE, &len);
                        if (error != 0)
                                return (error);
                        newval = bsd_to_linux_domain((sa_family_t)newval);
                        if (newval == AF_UNKNOWN)
                                return (ENOPROTOOPT);
                        return (linux_sockopt_copyout(td, &newval,
                            len, args));
                        /* NOTREACHED */
                case SO_LINGER:
                        return (linux_getsockopt_so_linger(td, args));
                        /* NOTREACHED */
                default:
                        break;
                }
                break;
        case IPPROTO_IP:
                name = linux_to_bsd_ip_sockopt(args->optname);
                break;
        case IPPROTO_IPV6:
                name = linux_to_bsd_ip6_sockopt(args->optname);
                break;
        case IPPROTO_TCP:
                name = linux_to_bsd_tcp_sockopt(args->optname);
                switch (name) {
                case TCP_MAXUNACKTIME:
                        len = sizeof(bsd_timeout);
                        error = kern_getsockopt(td, args->s, level, name,
                            &bsd_timeout, UIO_SYSSPACE, &len);
                        if (error != 0)
                                return (error);

                        linux_timeout = bsd_to_linux_tcp_user_timeout(
                            bsd_timeout);
                        return (linux_sockopt_copyout(td, &linux_timeout,
                            sizeof(linux_timeout), args));
                default:
                        break;
                }
                break;
        default:
                name = -1;
                break;
        }
        if (name < 0) {
                if (name == -1)
                        linux_msg(curthread,
                            "unsupported getsockopt level %d optname %d",
                            args->level, args->optname);
                return (EINVAL);
        }

        if (name == IPV6_NEXTHOP) {
                error = copyin(PTRIN(args->optlen), &len, sizeof(len));
                if (error != 0)
                        return (error);
                sa = malloc(len, M_SONAME, M_WAITOK);

                error = kern_getsockopt(td, args->s, level,
                    name, sa, UIO_SYSSPACE, &len);
                if (error != 0)
                        goto out;

                error = linux_copyout_sockaddr(sa, PTRIN(args->optval), len);
                if (error == 0)
                        error = copyout(&len, PTRIN(args->optlen),
                            sizeof(len));
out:
                free(sa, M_SONAME);
        } else {
                if (args->optval) {
                        error = copyin(PTRIN(args->optlen), &len, sizeof(len));
                        if (error != 0)
                                return (error);
                }
                error = kern_getsockopt(td, args->s, level,
                    name, PTRIN(args->optval), UIO_USERSPACE, &len);
                if (error == 0)
                        error = copyout(&len, PTRIN(args->optlen),
                            sizeof(len));
        }

        return (error);
}

/*
 * Based on sendfile_getsock from kern_sendfile.c
 * Determines whether an fd is a stream socket that can be used
 * with FreeBSD sendfile.
 */
static bool
is_sendfile(struct file *fp, struct file *ofp)
{
        struct socket *so;

        /*
         * FreeBSD sendfile() system call sends a regular file or
         * shared memory object out a stream socket.
         */
        if ((fp->f_type != DTYPE_SHM && fp->f_type != DTYPE_VNODE) ||
            (fp->f_type == DTYPE_VNODE &&
            (fp->f_vnode == NULL || fp->f_vnode->v_type != VREG)))
                return (false);
        /*
         * The socket must be a stream socket and connected.
         */
        if (ofp->f_type != DTYPE_SOCKET)
                return (false);
        so = ofp->f_data;
        if (so->so_type != SOCK_STREAM)
                return (false);
        /*
         * SCTP one-to-one style sockets currently don't work with
         * sendfile().
         */
        if (so->so_proto->pr_protocol == IPPROTO_SCTP)
                return (false);
        return (!SOLISTENING(so));
}

static bool
is_regular_file(struct file *fp)
{

        return (fp->f_type == DTYPE_VNODE && fp->f_vnode != NULL &&
            fp->f_vnode->v_type == VREG);
}

static int
sendfile_fallback(struct thread *td, struct file *fp, l_int out,
    off_t *offset, l_size_t count, off_t *sbytes)
{
        off_t current_offset, out_offset, to_send;
        l_size_t bytes_sent, n_read;
        struct file *ofp;
        struct iovec aiov;
        struct uio auio;
        bool seekable;
        size_t bufsz;
        void *buf;
        int flags, error;

        if (offset == NULL) {
                if ((error = fo_seek(fp, 0, SEEK_CUR, td)) != 0)
                        return (error);
                current_offset = td->td_uretoff.tdu_off;
        } else {
                if ((fp->f_ops->fo_flags & DFLAG_SEEKABLE) == 0)
                        return (ESPIPE);
                current_offset = *offset;
        }
        error = fget_write(td, out, &cap_pwrite_rights, &ofp);
        if (error != 0)
                return (error);
        seekable = (ofp->f_ops->fo_flags & DFLAG_SEEKABLE) != 0;
        if (seekable) {
                if ((error = fo_seek(ofp, 0, SEEK_CUR, td)) != 0)
                        goto drop;
                out_offset = td->td_uretoff.tdu_off;
        } else
                out_offset = 0;

        flags = FOF_OFFSET | FOF_NOUPDATE;
        bufsz = min(count, maxphys);
        buf = malloc(bufsz, M_LINUX, M_WAITOK);
        bytes_sent = 0;
        while (bytes_sent < count) {
                to_send = min(count - bytes_sent, bufsz);
                aiov.iov_base = buf;
                aiov.iov_len = bufsz;
                auio.uio_iov = &aiov;
                auio.uio_iovcnt = 1;
                auio.uio_segflg = UIO_SYSSPACE;
                auio.uio_td = td;
                auio.uio_rw = UIO_READ;
                auio.uio_offset = current_offset;
                auio.uio_resid = to_send;
                error = fo_read(fp, &auio, fp->f_cred, flags, td);
                if (error != 0)
                        break;
                n_read = to_send - auio.uio_resid;
                if (n_read == 0)
                        break;
                aiov.iov_base = buf;
                aiov.iov_len = bufsz;
                auio.uio_iov = &aiov;
                auio.uio_iovcnt = 1;
                auio.uio_segflg = UIO_SYSSPACE;
                auio.uio_td = td;
                auio.uio_rw = UIO_WRITE;
                auio.uio_offset = (seekable) ? out_offset : 0;
                auio.uio_resid = n_read;
                error = fo_write(ofp, &auio, ofp->f_cred, flags, td);
                if (error != 0)
                        break;
                bytes_sent += n_read;
                current_offset += n_read;
                out_offset += n_read;
        }
        free(buf, M_LINUX);

        if (error == 0) {
                *sbytes = bytes_sent;
                if (offset != NULL)
                        *offset = current_offset;
                else
                        error = fo_seek(fp, current_offset, SEEK_SET, td);
        }
        if (error == 0 && seekable)
                error = fo_seek(ofp, out_offset, SEEK_SET, td);

drop:
        fdrop(ofp, td);
        return (error);
}

static int
sendfile_sendfile(struct thread *td, struct file *fp, l_int out,
    off_t *offset, l_size_t count, off_t *sbytes)
{
        off_t current_offset;
        int error;

        if (offset == NULL) {
                if ((fp->f_ops->fo_flags & DFLAG_SEEKABLE) == 0)
                        return (ESPIPE);
                if ((error = fo_seek(fp, 0, SEEK_CUR, td)) != 0)
                        return (error);
                current_offset = td->td_uretoff.tdu_off;
        } else
                current_offset = *offset;
        error = fo_sendfile(fp, out, NULL, NULL, current_offset, count,
            sbytes, 0, td);
        if (error == EAGAIN && *sbytes > 0) {
                /*
                 * The socket is non-blocking and we didn't finish sending.
                 * Squash the error, since that's what Linux does.
                 */
                error = 0;
        }
        if (error == 0) {
                current_offset += *sbytes;
                if (offset != NULL)
                        *offset = current_offset;
                else
                        error = fo_seek(fp, current_offset, SEEK_SET, td);
        }
        return (error);
}

static int
linux_sendfile_common(struct thread *td, l_int out, l_int in,
    off_t *offset, l_size_t count)
{
        struct file *fp, *ofp;
        off_t sbytes;
        int error;

        /* Linux cannot have 0 count. */
        if (count <= 0 || (offset != NULL && *offset < 0))
                return (EINVAL);

        AUDIT_ARG_FD(in);
        error = fget_read(td, in, &cap_pread_rights, &fp);
        if (error != 0)
                return (error);
        if ((fp->f_type != DTYPE_SHM && fp->f_type != DTYPE_VNODE) ||
            (fp->f_type == DTYPE_VNODE &&
            (fp->f_vnode == NULL || fp->f_vnode->v_type != VREG))) {
                error = EINVAL;
                goto drop;
        }
        error = fget_unlocked(td, out, &cap_no_rights, &ofp);
        if (error != 0)
                goto drop;

        if (is_regular_file(fp) && is_regular_file(ofp)) {
                error = kern_copy_file_range(td, in, offset, out, NULL, count,
                    0);
        } else {
                sbytes = 0;
                if (is_sendfile(fp, ofp))
                        error = sendfile_sendfile(td, fp, out, offset, count,
                            &sbytes);
                else
                        error = sendfile_fallback(td, fp, out, offset, count,
                            &sbytes);
                if (error == ENOBUFS && (ofp->f_flag & FNONBLOCK) != 0)
                        error = EAGAIN;
                if (error == 0)
                        td->td_retval[0] = sbytes;
        }
        fdrop(ofp, td);

drop:
        fdrop(fp, td);
        return (error);
}

int
linux_sendfile(struct thread *td, struct linux_sendfile_args *arg)
{
        /*
         * Differences between FreeBSD and Linux sendfile:
         * - Linux doesn't send anything when count is 0 (FreeBSD uses 0 to
         *   mean send the whole file).
         * - Linux can send to any fd whereas FreeBSD only supports sockets.
         *   We therefore use FreeBSD sendfile where possible for performance,
         *   but fall back on a manual copy (sendfile_fallback).
         * - Linux doesn't have an equivalent for FreeBSD's flags and sf_hdtr.
         * - Linux takes an offset pointer and updates it to the read location.
         *   FreeBSD takes in an offset and a 'bytes read' parameter which is
         *   only filled if it isn't NULL.  We use this parameter to update the
         *   offset pointer if it exists.
         * - Linux sendfile returns bytes read on success while FreeBSD
         *   returns 0.  We use the 'bytes read' parameter to get this value.
         */

        off_t offset64;
        l_off_t offset;
        int error;

        if (arg->offset != NULL) {
                error = copyin(arg->offset, &offset, sizeof(offset));
                if (error != 0)
                        return (error);
                offset64 = offset;
        }

        error = linux_sendfile_common(td, arg->out, arg->in,
            arg->offset != NULL ? &offset64 : NULL, arg->count);

        if (error == 0 && arg->offset != NULL) {
#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
                if (offset64 > INT32_MAX)
                        return (EOVERFLOW);
#endif
                offset = (l_off_t)offset64;
                error = copyout(&offset, arg->offset, sizeof(offset));
        }

        return (error);
}

#if defined(__i386__) || (defined(__amd64__) && defined(COMPAT_LINUX32))
int
linux_sendfile64(struct thread *td, struct linux_sendfile64_args *arg)
{
        off_t offset;
        int error;

        if (arg->offset != NULL) {
                error = copyin(arg->offset, &offset, sizeof(offset));
                if (error != 0)
                        return (error);
        }

        error = linux_sendfile_common(td, arg->out, arg->in,
                arg->offset != NULL ? &offset : NULL, arg->count);

        if (error == 0 && arg->offset != NULL)
                error = copyout(&offset, arg->offset, sizeof(offset));

        return (error);
}

/* Argument list sizes for linux_socketcall */
static const unsigned char lxs_args_cnt[] = {
        0 /* unused*/,          3 /* socket */,
        3 /* bind */,           3 /* connect */,
        2 /* listen */,         3 /* accept */,
        3 /* getsockname */,    3 /* getpeername */,
        4 /* socketpair */,     4 /* send */,
        4 /* recv */,           6 /* sendto */,
        6 /* recvfrom */,       2 /* shutdown */,
        5 /* setsockopt */,     5 /* getsockopt */,
        3 /* sendmsg */,        3 /* recvmsg */,
        4 /* accept4 */,        5 /* recvmmsg */,
        4 /* sendmmsg */,       4 /* sendfile */
};
#define LINUX_ARGS_CNT          (nitems(lxs_args_cnt) - 1)
#define LINUX_ARG_SIZE(x)       (lxs_args_cnt[x] * sizeof(l_ulong))

int
linux_socketcall(struct thread *td, struct linux_socketcall_args *args)
{
        l_ulong a[6];
#if defined(__amd64__) && defined(COMPAT_LINUX32)
        register_t l_args[6];
#endif
        void *arg;
        int error;

        if (args->what < LINUX_SOCKET || args->what > LINUX_ARGS_CNT)
                return (EINVAL);
        error = copyin(PTRIN(args->args), a, LINUX_ARG_SIZE(args->what));
        if (error != 0)
                return (error);

#if defined(__amd64__) && defined(COMPAT_LINUX32)
        for (int i = 0; i < lxs_args_cnt[args->what]; ++i)
                l_args[i] = a[i];
        arg = l_args;
#else
        arg = a;
#endif
        switch (args->what) {
        case LINUX_SOCKET:
                return (linux_socket(td, arg));
        case LINUX_BIND:
                return (linux_bind(td, arg));
        case LINUX_CONNECT:
                return (linux_connect(td, arg));
        case LINUX_LISTEN:
                return (linux_listen(td, arg));
        case LINUX_ACCEPT:
                return (linux_accept(td, arg));
        case LINUX_GETSOCKNAME:
                return (linux_getsockname(td, arg));
        case LINUX_GETPEERNAME:
                return (linux_getpeername(td, arg));
        case LINUX_SOCKETPAIR:
                return (linux_socketpair(td, arg));
        case LINUX_SEND:
                return (linux_send(td, arg));
        case LINUX_RECV:
                return (linux_recv(td, arg));
        case LINUX_SENDTO:
                return (linux_sendto(td, arg));
        case LINUX_RECVFROM:
                return (linux_recvfrom(td, arg));
        case LINUX_SHUTDOWN:
                return (linux_shutdown(td, arg));
        case LINUX_SETSOCKOPT:
                return (linux_setsockopt(td, arg));
        case LINUX_GETSOCKOPT:
                return (linux_getsockopt(td, arg));
        case LINUX_SENDMSG:
                return (linux_sendmsg(td, arg));
        case LINUX_RECVMSG:
                return (linux_recvmsg(td, arg));
        case LINUX_ACCEPT4:
                return (linux_accept4(td, arg));
        case LINUX_RECVMMSG:
                return (linux_recvmmsg(td, arg));
        case LINUX_SENDMMSG:
                return (linux_sendmmsg(td, arg));
        case LINUX_SENDFILE:
                return (linux_sendfile(td, arg));
        }

        linux_msg(td, "socket type %d not implemented", args->what);
        return (ENOSYS);
}
#endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */