etc/services - sync with NetBSD-8

[minix.git] / minix / net / lwip / udpsock.c

/* LWIP service - udpsock.c - UDP sockets */

#include "lwip.h"
#include "ifaddr.h"
#include "pktsock.h"

#include "lwip/udp.h"

#include <netinet/udp.h>
#include <netinet/ip_var.h>
#include <netinet/udp_var.h>

/* The number of UDP sockets.  Inherited from the lwIP configuration. */
#define NR_UDPSOCK      MEMP_NUM_UDP_PCB

/*
 * Outgoing packets are not getting buffered, so the send buffer size simply
 * determines the maximum size for sent packets.  The send buffer maximum is
 * therefore limited to the maximum size of a single packet (64K-1 bytes),
 * which is already enforced by lwIP's 16-bit length parameter to pbuf_alloc().
 *
 * The actual transmission may enforce a lower limit, though.  The full packet
 * size must not exceed the same 64K-1 limit, and that includes any headers
 * that still have to be prepended to the given packet.  The size of those
 * headers depends on the socket type (IPv4/IPv6) and the IP_HDRINCL setting.
 */
#define UDP_MAX_PAYLOAD (UINT16_MAX)

#define UDP_SNDBUF_MIN  1               /* minimum UDP send buffer size */
#define UDP_SNDBUF_DEF  8192            /* default UDP send buffer size */
#define UDP_SNDBUF_MAX  UDP_MAX_PAYLOAD /* maximum UDP send buffer size */
#define UDP_RCVBUF_MIN  MEMPOOL_BUFSIZE /* minimum UDP receive buffer size */
#define UDP_RCVBUF_DEF  32768           /* default UDP receive buffer size */
#define UDP_RCVBUF_MAX  65536           /* maximum UDP receive buffer size */

static struct udpsock {
        struct pktsock udp_pktsock;             /* pkt socket, MUST be first */
        struct udp_pcb *udp_pcb;                /* lwIP UDP control block */
        SIMPLEQ_ENTRY(udpsock) udp_next;        /* next in free list */
} udp_array[NR_UDPSOCK];

static SIMPLEQ_HEAD(, udpsock) udp_freelist;    /* list of free UDP sockets */

static const struct sockevent_ops udpsock_ops;

#define udpsock_get_sock(udp)   (ipsock_get_sock(udpsock_get_ipsock(udp)))
#define udpsock_get_ipsock(udp) (pktsock_get_ipsock(&(udp)->udp_pktsock))
#define udpsock_is_ipv6(udp)    (ipsock_is_ipv6(udpsock_get_ipsock(udp)))
#define udpsock_is_conn(udp)    \
        (udp_flags((udp)->udp_pcb) & UDP_FLAGS_CONNECTED)

static ssize_t udpsock_pcblist(struct rmib_call *, struct rmib_node *,
        struct rmib_oldp *, struct rmib_newp *);

/* The CTL_NET {PF_INET,PF_INET6} IPPROTO_UDP subtree. */
/* TODO: add many more and make some of them writable.. */
static struct rmib_node net_inet_udp_table[] = {
/* 1*/  [UDPCTL_CHECKSUM]       = RMIB_INT(RMIB_RO, 1, "checksum",
                                    "Compute UDP checksums"),
/* 2*/  [UDPCTL_SENDSPACE]      = RMIB_INT(RMIB_RO, UDP_SNDBUF_DEF,
                                    "sendspace",
                                    "Default UDP send buffer size"),
/* 3*/  [UDPCTL_RECVSPACE]      = RMIB_INT(RMIB_RO, UDP_RCVBUF_DEF,
                                    "recvspace",
                                    "Default UDP receive buffer size"),
/* 4*/  [UDPCTL_LOOPBACKCKSUM]  = RMIB_FUNC(RMIB_RW | CTLTYPE_INT, sizeof(int),
                                    loopif_cksum, "do_loopback_cksum",
                                    "Perform UDP checksum on loopback"),
/*+0*/  [UDPCTL_MAXID]          = RMIB_FUNC(RMIB_RO | CTLTYPE_NODE, 0,
                                    udpsock_pcblist, "pcblist",
                                    "UDP protocol control block list"),
};

static struct rmib_node net_inet_udp_node =
    RMIB_NODE(RMIB_RO, net_inet_udp_table, "udp", "UDPv4 related settings");
static struct rmib_node net_inet6_udp6_node =
    RMIB_NODE(RMIB_RO, net_inet_udp_table, "udp6", "UDPv6 related settings");

/*
 * Initialize the UDP sockets module.
 */
void
udpsock_init(void)
{
        unsigned int slot;

        /* Initialize the list of free UDP sockets. */
        SIMPLEQ_INIT(&udp_freelist);

        for (slot = 0; slot < __arraycount(udp_array); slot++)
                SIMPLEQ_INSERT_TAIL(&udp_freelist, &udp_array[slot], udp_next);

        /* Register the net.inet.udp and net.inet6.udp6 RMIB subtrees. */
        mibtree_register_inet(PF_INET, IPPROTO_UDP, &net_inet_udp_node);
        mibtree_register_inet(PF_INET6, IPPROTO_UDP, &net_inet6_udp6_node);
}

/*
 * A packet has arrived on a UDP socket.  We own the given packet buffer, and
 * so we must free it if we do not want to keep it.
 */
static void
udpsock_input(void * arg, struct udp_pcb * pcb __unused, struct pbuf * pbuf,
        const ip_addr_t * ipaddr, uint16_t port)
{
        struct udpsock *udp = (struct udpsock *)arg;

        /* All UDP input processing is handled by pktsock. */
        pktsock_input(&udp->udp_pktsock, pbuf, ipaddr, port);
}

/*
 * Create a UDP socket.
 */
sockid_t
udpsock_socket(int domain, int protocol, struct sock ** sockp,
        const struct sockevent_ops ** ops)
{
        struct udpsock *udp;
        unsigned int flags;
        uint8_t ip_type;

        switch (protocol) {
        case 0:
        case IPPROTO_UDP:
                break;

        /* NetBSD does not support IPPROTO_UDPLITE, even though lwIP does. */
        default:
                return EPROTONOSUPPORT;
        }

        if (SIMPLEQ_EMPTY(&udp_freelist))
                return ENOBUFS;

        udp = SIMPLEQ_FIRST(&udp_freelist);

        ip_type = pktsock_socket(&udp->udp_pktsock, domain, UDP_SNDBUF_DEF,
            UDP_RCVBUF_DEF, sockp);

        /* We should have enough PCBs so this call should not fail.. */
        if ((udp->udp_pcb = udp_new_ip_type(ip_type)) == NULL)
                return ENOBUFS;
        udp_recv(udp->udp_pcb, udpsock_input, (void *)udp);

        /* By default, the multicast TTL is 1 and looping is enabled. */
        udp_set_multicast_ttl(udp->udp_pcb, 1);

        flags = udp_flags(udp->udp_pcb);
        udp_setflags(udp->udp_pcb, flags | UDP_FLAGS_MULTICAST_LOOP);

        SIMPLEQ_REMOVE_HEAD(&udp_freelist, udp_next);

        *ops = &udpsock_ops;
        return SOCKID_UDP | (sockid_t)(udp - udp_array);
}

/*
 * Bind a UDP socket to a local address.
 */
static int
udpsock_bind(struct sock * sock, const struct sockaddr * addr,
        socklen_t addr_len, endpoint_t user_endpt)
{
        struct udpsock *udp = (struct udpsock *)sock;
        ip_addr_t ipaddr;
        uint16_t port;
        err_t err;
        int r;

        if ((r = ipsock_get_src_addr(udpsock_get_ipsock(udp), addr, addr_len,
            user_endpt, &udp->udp_pcb->local_ip, udp->udp_pcb->local_port,
            TRUE /*allow_mcast*/, &ipaddr, &port)) != OK)
                return r;

        err = udp_bind(udp->udp_pcb, &ipaddr, port);

        return util_convert_err(err);
}

/*
 * Connect a UDP socket to a remote address.
 */
static int
udpsock_connect(struct sock * sock, const struct sockaddr * addr,
        socklen_t addr_len, endpoint_t user_endpt __unused)
{
        struct udpsock *udp = (struct udpsock *)sock;
        struct ifdev *ifdev;
        const ip_addr_t *src_addr;
        ip_addr_t dst_addr;
        uint16_t dst_port;
        uint32_t ifindex, ifindex2;
        err_t err;
        int r;

        /*
         * One may "unconnect" socket by providing an address with family
         * AF_UNSPEC.  Providing an <any>:0 address does not achieve the same.
         */
        if (addr_is_unspec(addr, addr_len)) {
                udp_disconnect(udp->udp_pcb);

                return OK;
        }

        if ((r = ipsock_get_dst_addr(udpsock_get_ipsock(udp), addr,
            addr_len, &udp->udp_pcb->local_ip, &dst_addr, &dst_port)) != OK)
                return r;

        /*
         * Bind explicitly to a source address if the PCB is not bound to one
         * yet.  This is expected in the BSD socket API, but lwIP does not do
         * it for us.
         */
        if (ip_addr_isany(&udp->udp_pcb->local_ip)) {
                /* Help the multicast case a bit, if possible. */
                ifdev = NULL;

                if (ip_addr_ismulticast(&dst_addr)) {
                        ifindex = pktsock_get_ifindex(&udp->udp_pktsock);
                        ifindex2 = udp_get_multicast_netif_index(udp->udp_pcb);
                        if (ifindex == 0)
                                ifindex = ifindex2;

                        if (ifindex != 0) {
                                ifdev = ifdev_get_by_index(ifindex);

                                if (ifdev == NULL)
                                        return ENXIO;
                        }
                }

                src_addr = ifaddr_select(&dst_addr, ifdev, NULL /*ifdevp*/);

                if (src_addr == NULL)
                        return EHOSTUNREACH;

                err = udp_bind(udp->udp_pcb, src_addr,
                    udp->udp_pcb->local_port);

                if (err != ERR_OK)
                        return util_convert_err(err);
        }

        /*
         * Connecting a UDP socket serves two main purposes: 1) the socket uses
         * the address as destination when sending, and 2) the socket receives
         * packets from only the connected address.
         */
        err = udp_connect(udp->udp_pcb, &dst_addr, dst_port);

        if (err != ERR_OK)
                return util_convert_err(err);

        return OK;
}

/*
 * Perform preliminary checks on a send request.
 */
static int
udpsock_pre_send(struct sock * sock, size_t len, socklen_t ctl_len __unused,
        const struct sockaddr * addr, socklen_t addr_len __unused,
        endpoint_t user_endpt __unused, int flags)
{
        struct udpsock *udp = (struct udpsock *)sock;

        if ((flags & ~MSG_DONTROUTE) != 0)
                return EOPNOTSUPP;

        if (!udpsock_is_conn(udp) && addr == NULL)
                return EDESTADDRREQ;

        /*
         * This is only one part of the length check.  The rest is done from
         * udpsock_send(), once we have more information.
         */
        if (len > ipsock_get_sndbuf(udpsock_get_ipsock(udp)))
                return EMSGSIZE;

        return OK;
}

/*
 * Swap IP-level options between the UDP PCB and the packet options structure,
 * for all options that have their flag set in the packet options structure.
 * This function is called twice when sending a packet.  The result is that the
 * flagged options are overridden for only the packet being sent.
 */
static void
udpsock_swap_opt(struct udpsock * udp, struct pktopt * pkto)
{
        uint8_t tos, ttl, mcast_ttl;

        if (pkto->pkto_flags & PKTOF_TOS) {
                tos = udp->udp_pcb->tos;
                udp->udp_pcb->tos = pkto->pkto_tos;
                pkto->pkto_tos = tos;
        }

        if (pkto->pkto_flags & PKTOF_TTL) {
                ttl = udp->udp_pcb->ttl;
                mcast_ttl = udp_get_multicast_ttl(udp->udp_pcb);
                udp->udp_pcb->ttl = pkto->pkto_ttl;
                udp_set_multicast_ttl(udp->udp_pcb, pkto->pkto_mcast_ttl);
                pkto->pkto_ttl = ttl;
                pkto->pkto_mcast_ttl = mcast_ttl;
        }
}

/*
 * Send a packet on a UDP socket.
 */
static int
udpsock_send(struct sock * sock, const struct sockdriver_data * data,
        size_t len, size_t * off, const struct sockdriver_data * ctl,
        socklen_t ctl_len, socklen_t * ctl_off __unused,
        const struct sockaddr * addr, socklen_t addr_len,
        endpoint_t user_endpt __unused, int flags, size_t min __unused)
{
        struct udpsock *udp = (struct udpsock *)sock;
        struct pktopt pktopt;
        struct pbuf *pbuf;
        struct ifdev *ifdev;
        struct netif *netif;
        const ip_addr_t *src_addrp, *dst_addrp;
        ip_addr_t src_addr, dst_addr; /* for storage only; not always used! */
        uint16_t dst_port;
        uint32_t ifindex;
        size_t hdrlen;
        err_t err;
        int r;

        /* Copy in and parse any packet options. */
        pktopt.pkto_flags = 0;

        if ((r = pktsock_get_ctl(&udp->udp_pktsock, ctl, ctl_len,
            &pktopt)) != OK)
                return r;

        /*
         * The code below will both determine an outgoing interface and a
         * source address for the packet.  Even though lwIP could do this for
         * us in some cases, there are other cases where we must do so
         * ourselves, with as main reasons 1) the possibility that either or
         * both have been provided through IPV6_PKTINFO, and 2) our intent to
         * detect and stop zone violations for (combinations of) scoped IPv6
         * addresses.  As a result, it is easier to simply take over the
         * selection tasks lwIP in their entirety.
         *
         * Much of the same applies to rawsock_send() as well.  Functional
         * differences (e.g. IP_HDRINCL support) as well as the PCB accesses in
         * the code make it hard to merge the two into a single pktsock copy.
         * Please do keep the two in sync as much as possible.
         */

        /*
         * Start by checking whether the source address and/or the outgoing
         * interface are overridden using sticky and/or ancillary options.  The
         * call to pktsock_get_pktinfo(), if successful, will either set
         * 'ifdev' to NULL, in which case there is no override, or it will set
         * 'ifdev' to the outgoing interface to use, and (only) in that case
         * also fill 'src_addr', with an address that may either be a locally
         * owned unicast address or the unspecified ('any') address.  If it is
         * a unicast address, that is the source address to use for the packet.
         * Otherwise, fall back to the address to which the socket is bound,
         * which may also be the unspecified address or even a multicast
         * address.  In those case we will pick a source address further below.
         */
        if ((r = pktsock_get_pktinfo(&udp->udp_pktsock, &pktopt, &ifdev,
            &src_addr)) != OK)
                return r;

        if (ifdev != NULL && !ip_addr_isany(&src_addr)) {
                /* This is guaranteed to be a proper local unicast address. */
                src_addrp = &src_addr;
        } else {
                src_addrp = &udp->udp_pcb->local_ip;

                /*
                 * If the socket is bound to a multicast address, use the
                 * unspecified ('any') address as source address instead, until
                 * we select a real source address (further below).  This
                 * substitution keeps the rest of the code a bit simpler.
                 */
                if (ip_addr_ismulticast(src_addrp))
                        src_addrp = IP46_ADDR_ANY(IP_GET_TYPE(src_addrp));
        }

        /*
         * Determine the destination address to use.  If the socket is
         * connected, always ignore any address provided in the send call.
         */
        if (!udpsock_is_conn(udp)) {
                assert(addr != NULL); /* already checked in pre_send */

                if ((r = ipsock_get_dst_addr(udpsock_get_ipsock(udp), addr,
                    addr_len, src_addrp, &dst_addr, &dst_port)) != OK)
                        return r;

                dst_addrp = &dst_addr;
        } else {
                dst_addrp = &udp->udp_pcb->remote_ip;
                dst_port = udp->udp_pcb->remote_port;
        }

        /*
         * If the destination is a multicast address, select the outgoing
         * interface based on the multicast interface index, if one is set.
         * This must be done here in order to allow the code further below to
         * detect zone violations, because if we leave this selection to lwIP,
         * it will not perform zone violation detection at all.  Also note that
         * this case must *not* override an interface index already specified
         * using IPV6_PKTINFO, as per RFC 3542 Sec. 6.7.
         */
        if (ifdev == NULL && ip_addr_ismulticast(dst_addrp)) {
                ifindex = udp_get_multicast_netif_index(udp->udp_pcb);

                if (ifindex != NETIF_NO_INDEX)
                        ifdev = ifdev_get_by_index(ifindex); /* (may fail) */
        }

        /*
         * If an interface has been determined already now, the send operation
         * will bypass routing.  In that case, we must perform our own checks
         * on address zone violations, because those will not be made anywhere
         * else.  Subsequent steps below will never introduce violations.
         */
        if (ifdev != NULL && IP_IS_V6(dst_addrp)) {
                if (ifaddr_is_zone_mismatch(ip_2_ip6(dst_addrp), ifdev))
                        return EHOSTUNREACH;

                if (IP_IS_V6(src_addrp) &&
                    ifaddr_is_zone_mismatch(ip_2_ip6(src_addrp), ifdev))
                        return EHOSTUNREACH;
        }

        /*
         * If we do not yet have an interface at this point, perform a route
         * lookup to determine the outgoing interface.  Unless MSG_DONTROUTE is
         * set (which covers SO_DONTROUTE as well), in which case we look for a
         * local subnet that matches the destination address.
         */
        if (ifdev == NULL) {
                if (!(flags & MSG_DONTROUTE)) {
                        /*
                         * ip_route() should never be called with an
                         * IPADDR_TYPE_ANY type address.  This is a lwIP-
                         * internal requirement; while we override both routing
                         * functions, we do not deviate from it.
                         */
                        if (IP_IS_ANY_TYPE_VAL(*src_addrp))
                                src_addrp =
                                    IP46_ADDR_ANY(IP_GET_TYPE(dst_addrp));

                        /* Perform the route lookup. */
                        if ((netif = ip_route(src_addrp, dst_addrp)) == NULL)
                                return EHOSTUNREACH;

                        ifdev = netif_get_ifdev(netif);
                } else {
                        if ((ifdev = ifaddr_map_by_subnet(dst_addrp)) == NULL)
                                return EHOSTUNREACH;
                }
        }

        /*
         * At this point we have an outgoing interface.  If we do not have a
         * source address yet, pick one now.
         */
        assert(ifdev != NULL);

        if (ip_addr_isany(src_addrp)) {
                src_addrp = ifaddr_select(dst_addrp, ifdev, NULL /*ifdevp*/);

                if (src_addrp == NULL)
                        return EHOSTUNREACH;
        }

        /*
         * Now that we know the full conditions of what we are about to send,
         * check whether the packet size leaves enough room for lwIP to prepend
         * headers.  If so, allocate a chain of pbufs for the packet.
         */
        assert(len <= UDP_MAX_PAYLOAD);

        if (IP_IS_V6(dst_addrp))
                hdrlen = IP6_HLEN + UDP_HLEN;
        else
                hdrlen = IP_HLEN + UDP_HLEN;

        if (hdrlen + len > UDP_MAX_PAYLOAD)
                return EMSGSIZE;

        if ((pbuf = pchain_alloc(PBUF_TRANSPORT, len)) == NULL)
                return ENOBUFS;

        /* Copy in the packet data. */
        if ((r = pktsock_get_data(&udp->udp_pktsock, data, len, pbuf)) != OK) {
                pbuf_free(pbuf);

                return r;
        }

        /*
         * Set broadcast/multicast flags for accounting purposes.  Only the
         * multicast flag is used for output accounting, but for loopback
         * traffic, both flags are copied and used for input accounting and
         * setting MSG_MCAST/MSG_BCAST.
         */
        if (ip_addr_ismulticast(dst_addrp))
                pbuf->flags |= PBUF_FLAG_LLMCAST;
        else if (ip_addr_isbroadcast(dst_addrp, ifdev_get_netif(ifdev)))
                pbuf->flags |= PBUF_FLAG_LLBCAST;

        /* Send the packet. */
        udpsock_swap_opt(udp, &pktopt);

        assert(!ip_addr_isany(src_addrp));
        assert(!ip_addr_ismulticast(src_addrp));

        err = udp_sendto_if_src(udp->udp_pcb, pbuf, dst_addrp, dst_port,
            ifdev_get_netif(ifdev), src_addrp);

        udpsock_swap_opt(udp, &pktopt);

        /* Free the pbuf, as a copy has been made. */
        pbuf_free(pbuf);

        /*
         * On success, make sure to return the size of the sent packet as well.
         * As an aside: ctl_off need not be updated, as it is not returned.
         */
        if ((r = util_convert_err(err)) == OK)
                *off = len;
        return r;
}

/*
 * Update the set of flag-type socket options on a UDP socket.
 */
static void
udpsock_setsockmask(struct sock * sock, unsigned int mask)
{
        struct udpsock *udp = (struct udpsock *)sock;

        if (mask & SO_REUSEADDR)
                ip_set_option(udp->udp_pcb, SOF_REUSEADDR);
        else
                ip_reset_option(udp->udp_pcb, SOF_REUSEADDR);

        if (mask & SO_BROADCAST)
                ip_set_option(udp->udp_pcb, SOF_BROADCAST);
        else
                ip_reset_option(udp->udp_pcb, SOF_BROADCAST);
}

/*
 * Prepare a helper structure for IP-level option processing.
 */
static void
udpsock_get_ipopts(struct udpsock * udp, struct ipopts * ipopts)
{

        ipopts->local_ip = &udp->udp_pcb->local_ip;
        ipopts->remote_ip = &udp->udp_pcb->remote_ip;
        ipopts->tos = &udp->udp_pcb->tos;
        ipopts->ttl = &udp->udp_pcb->ttl;
        ipopts->sndmin = UDP_SNDBUF_MIN;
        ipopts->sndmax = UDP_SNDBUF_MAX;
        ipopts->rcvmin = UDP_RCVBUF_MIN;
        ipopts->rcvmax = UDP_RCVBUF_MAX;
}

/*
 * Set socket options on a UDP socket.
 */
static int
udpsock_setsockopt(struct sock * sock, int level, int name,
        const struct sockdriver_data * data, socklen_t len)
{
        struct udpsock *udp = (struct udpsock *)sock;
        struct ipopts ipopts;
        ip_addr_t ipaddr;
        struct in_addr in_addr;
        struct ifdev *ifdev;
        unsigned int flags;
        uint32_t ifindex;
        uint8_t byte;
        int r, val;

        /*
         * Unfortunately, we have to duplicate most of the multicast options
         * rather than sharing them with rawsock at the pktsock level.  The
         * reason is that each of the PCBs have their own multicast abstraction
         * functions and so we cannot merge the rest.  Same for getsockopt.
         */

        switch (level) {
        case IPPROTO_IP:
                if (udpsock_is_ipv6(udp))
                        break;

                switch (name) {
                case IP_MULTICAST_IF:
                        pktsock_set_mcaware(&udp->udp_pktsock);

                        if ((r = sockdriver_copyin_opt(data, &in_addr,
                            sizeof(in_addr), len)) != OK)
                                return r;

                        ip_addr_set_ip4_u32(&ipaddr, in_addr.s_addr);

                        if ((ifdev = ifaddr_map_by_addr(&ipaddr)) == NULL)
                                return EADDRNOTAVAIL;

                        udp_set_multicast_netif_index(udp->udp_pcb,
                            ifdev_get_index(ifdev));

                        return OK;

                case IP_MULTICAST_LOOP:
                        pktsock_set_mcaware(&udp->udp_pktsock);

                        if ((r = sockdriver_copyin_opt(data, &byte,
                            sizeof(byte), len)) != OK)
                                return r;

                        flags = udp_flags(udp->udp_pcb);

                        if (byte)
                                flags |= UDP_FLAGS_MULTICAST_LOOP;
                        else
                                flags &= ~UDP_FLAGS_MULTICAST_LOOP;

                        udp_setflags(udp->udp_pcb, flags);

                        return OK;

                case IP_MULTICAST_TTL:
                        pktsock_set_mcaware(&udp->udp_pktsock);

                        if ((r = sockdriver_copyin_opt(data, &byte,
                            sizeof(byte), len)) != OK)
                                return r;

                        udp_set_multicast_ttl(udp->udp_pcb, byte);

                        return OK;
                }

                break;

        case IPPROTO_IPV6:
                if (!udpsock_is_ipv6(udp))
                        break;

                switch (name) {
                case IPV6_MULTICAST_IF:
                        pktsock_set_mcaware(&udp->udp_pktsock);

                        if ((r = sockdriver_copyin_opt(data, &val, sizeof(val),
                            len)) != OK)
                                return r;

                        if (val != 0) {
                                ifindex = (uint32_t)val;

                                ifdev = ifdev_get_by_index(ifindex);

                                if (ifdev == NULL)
                                        return ENXIO;
                        } else
                                ifindex = NETIF_NO_INDEX;

                        udp_set_multicast_netif_index(udp->udp_pcb, ifindex);

                        return OK;

                case IPV6_MULTICAST_LOOP:
                        pktsock_set_mcaware(&udp->udp_pktsock);

                        if ((r = sockdriver_copyin_opt(data, &val, sizeof(val),
                            len)) != OK)
                                return r;

                        if (val < 0 || val > 1)
                                return EINVAL;

                        flags = udp_flags(udp->udp_pcb);

                        if (val)
                                flags |= UDP_FLAGS_MULTICAST_LOOP;
                        else
                                flags &= ~UDP_FLAGS_MULTICAST_LOOP;

                        /*
                         * lwIP's IPv6 functionality does not actually check
                         * this flag at all yet.  We set it in the hope that
                         * one day this will magically start working.
                         */
                        udp_setflags(udp->udp_pcb, flags);

                        return OK;

                case IPV6_MULTICAST_HOPS:
                        pktsock_set_mcaware(&udp->udp_pktsock);

                        if ((r = sockdriver_copyin_opt(data, &val, sizeof(val),
                            len)) != OK)
                                return r;

                        if (val < -1 || val > UINT8_MAX)
                                return EINVAL;

                        if (val == -1)
                                val = 1;

                        udp_set_multicast_ttl(udp->udp_pcb, val);

                        return OK;
                }

                break;
        }

        /* Handle all other options at the packet or IP level. */
        udpsock_get_ipopts(udp, &ipopts);

        return pktsock_setsockopt(&udp->udp_pktsock, level, name, data, len,
            &ipopts);
}

/*
 * Retrieve socket options on a UDP socket.
 */
static int
udpsock_getsockopt(struct sock * sock, int level, int name,
        const struct sockdriver_data * data, socklen_t * len)
{
        struct udpsock *udp = (struct udpsock *)sock;
        struct ipopts ipopts;
        const ip4_addr_t *ip4addr;
        struct in_addr in_addr;
        struct ifdev *ifdev;
        unsigned int flags;
        uint32_t ifindex;
        uint8_t byte;
        int val;

        switch (level) {
        case IPPROTO_IP:
                if (udpsock_is_ipv6(udp))
                        break;

                switch (name) {
                case IP_MULTICAST_IF:
                        ifindex = udp_get_multicast_netif_index(udp->udp_pcb);

                        /*
                         * Map back from the interface index to the IPv4
                         * address assigned to the corresponding interface.
                         * Should this not work out, return the 'any' address.
                         */
                        if (ifindex != NETIF_NO_INDEX &&
                           (ifdev = ifdev_get_by_index(ifindex)) != NULL) {
                                ip4addr =
                                    netif_ip4_addr(ifdev_get_netif(ifdev));

                                in_addr.s_addr = ip4_addr_get_u32(ip4addr);
                        } else
                                in_addr.s_addr = PP_HTONL(INADDR_ANY);

                        return sockdriver_copyout_opt(data, &in_addr,
                            sizeof(in_addr), len);

                case IP_MULTICAST_LOOP:
                        flags = udp_flags(udp->udp_pcb);

                        byte = !!(flags & UDP_FLAGS_MULTICAST_LOOP);

                        return sockdriver_copyout_opt(data, &byte,
                            sizeof(byte), len);

                case IP_MULTICAST_TTL:
                        byte = udp_get_multicast_ttl(udp->udp_pcb);

                        return sockdriver_copyout_opt(data, &byte,
                            sizeof(byte), len);
                }

                break;

        case IPPROTO_IPV6:
                if (!udpsock_is_ipv6(udp))
                        break;

                switch (name) {
                case IPV6_MULTICAST_IF:
                        ifindex = udp_get_multicast_netif_index(udp->udp_pcb);

                        val = (int)ifindex;

                        return sockdriver_copyout_opt(data, &val, sizeof(val),
                            len);

                case IPV6_MULTICAST_LOOP:
                        flags = udp_flags(udp->udp_pcb);

                        val = !!(flags & UDP_FLAGS_MULTICAST_LOOP);

                        return sockdriver_copyout_opt(data, &val, sizeof(val),
                            len);

                case IPV6_MULTICAST_HOPS:
                        val = udp_get_multicast_ttl(udp->udp_pcb);

                        return sockdriver_copyout_opt(data, &val, sizeof(val),
                            len);
                }

                break;
        }

        /* Handle all other options at the packet or IP level. */
        udpsock_get_ipopts(udp, &ipopts);

        return pktsock_getsockopt(&udp->udp_pktsock, level, name, data, len,
            &ipopts);
}

/*
 * Retrieve the local socket address of a UDP socket.
 */
static int
udpsock_getsockname(struct sock * sock, struct sockaddr * addr,
        socklen_t * addr_len)
{
        struct udpsock *udp = (struct udpsock *)sock;

        ipsock_put_addr(udpsock_get_ipsock(udp), addr, addr_len,
            &udp->udp_pcb->local_ip, udp->udp_pcb->local_port);

        return OK;
}

/*
 * Retrieve the remote socket address of a UDP socket.
 */
static int
udpsock_getpeername(struct sock * sock, struct sockaddr * addr,
        socklen_t * addr_len)
{
        struct udpsock *udp = (struct udpsock *)sock;

        if (!udpsock_is_conn(udp))
                return ENOTCONN;

        ipsock_put_addr(udpsock_get_ipsock(udp), addr, addr_len,
            &udp->udp_pcb->remote_ip, udp->udp_pcb->remote_port);

        return OK;
}

/*
 * Shut down a UDP socket for reading and/or writing.
 */
static int
udpsock_shutdown(struct sock * sock, unsigned int mask)
{
        struct udpsock *udp = (struct udpsock *)sock;

        if (mask & SFL_SHUT_RD)
                udp_recv(udp->udp_pcb, NULL, NULL);

        pktsock_shutdown(&udp->udp_pktsock, mask);

        return OK;
}

/*
 * Close a UDP socket.
 */
static int
udpsock_close(struct sock * sock, int force __unused)
{
        struct udpsock *udp = (struct udpsock *)sock;

        udp_recv(udp->udp_pcb, NULL, NULL);

        udp_remove(udp->udp_pcb);
        udp->udp_pcb = NULL;

        pktsock_close(&udp->udp_pktsock);

        return OK;
}

/*
 * Free up a closed UDP socket.
 */
static void
udpsock_free(struct sock * sock)
{
        struct udpsock *udp = (struct udpsock *)sock;

        assert(udp->udp_pcb == NULL);

        SIMPLEQ_INSERT_HEAD(&udp_freelist, udp, udp_next);
}

/*
 * Fill the given kinfo_pcb sysctl(7) structure with information about the UDP
 * PCB identified by the given pointer.
 */
static void
udpsock_get_info(struct kinfo_pcb * ki, const void * ptr)
{
        const struct udp_pcb *pcb = (const struct udp_pcb *)ptr;
        struct udpsock *udp;

        ki->ki_type = SOCK_DGRAM;

        /*
         * All UDP sockets should be created by this module, but protect
         * ourselves from the case that that is not true anyway.
         */
        if (pcb->recv_arg != NULL) {
                udp = (struct udpsock *)pcb->recv_arg;

                assert(udp >= udp_array &&
                    udp < &udp_array[__arraycount(udp_array)]);
        } else
                udp = NULL;

        ipsock_get_info(ki, &pcb->local_ip, pcb->local_port, &pcb->remote_ip,
            pcb->remote_port);

        if (udp != NULL) {
                /* TODO: change this so that sockstat(1) may work one day. */
                ki->ki_sockaddr = (uint64_t)(uintptr_t)udpsock_get_sock(udp);

                ki->ki_rcvq = pktsock_get_recvlen(&udp->udp_pktsock);
        }
}

/*
 * Given either NULL or a previously returned UDP PCB pointer, return the first
 * or next UDP PCB pointer, or NULL if there are no more.  Skip UDP PCBs that
 * are not bound to an address, as there is no use reporting them.
 */
static const void *
udpsock_enum(const void * last)
{
        const struct udp_pcb *pcb;

        if (last != NULL)
                pcb = (const void *)((const struct udp_pcb *)last)->next;
        else
                pcb = (const void *)udp_pcbs;

        while (pcb != NULL && pcb->local_port == 0)
                pcb = pcb->next;

        return pcb;
}

/*
 * Obtain the list of UDP protocol control blocks, for sysctl(7).
 */
static ssize_t
udpsock_pcblist(struct rmib_call * call, struct rmib_node * node __unused,
        struct rmib_oldp * oldp, struct rmib_newp * newp __unused)
{

        return util_pcblist(call, oldp, udpsock_enum, udpsock_get_info);
}

static const struct sockevent_ops udpsock_ops = {
        .sop_bind               = udpsock_bind,
        .sop_connect            = udpsock_connect,
        .sop_pre_send           = udpsock_pre_send,
        .sop_send               = udpsock_send,
        .sop_pre_recv           = pktsock_pre_recv,
        .sop_recv               = pktsock_recv,
        .sop_test_recv          = pktsock_test_recv,
        .sop_ioctl              = ifconf_ioctl,
        .sop_setsockmask        = udpsock_setsockmask,
        .sop_setsockopt         = udpsock_setsockopt,
        .sop_getsockopt         = udpsock_getsockopt,
        .sop_getsockname        = udpsock_getsockname,
        .sop_getpeername        = udpsock_getpeername,
        .sop_shutdown           = udpsock_shutdown,
        .sop_close              = udpsock_close,
        .sop_free               = udpsock_free
};