unix.c

/**
 @file  unix.c
 @brief ENet Unix system specific functions
*/
#ifndef _WIN32

// Required for IPV6_PKTINFO with Darwin headers
#ifndef __APPLE_USE_RFC_3542
#define __APPLE_USE_RFC_3542 1
#endif

// Required for in6_pktinfo with glibc headers
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <sys/time.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <time.h>

#define ENET_BUILDING_LIB 1
#include "enet/enet.h"

#if defined(__APPLE__)
#if !defined(IPV6_RECVPKTINFO) || !defined(IPV6_PKTINFO)
#warning Missing IPv6 socket option definitions. Is __APPLE_USE_RFC_3542 defined?
#endif
#ifndef HAS_POLL
#define HAS_POLL 1
#endif
#ifndef HAS_FCNTL
#define HAS_FCNTL 1
#endif
#ifndef HAS_INET_PTON
#define HAS_INET_PTON 1
#endif
#ifndef HAS_INET_NTOP
#define HAS_INET_NTOP 1
#endif
#ifndef HAS_MSGHDR_FLAGS
#define HAS_MSGHDR_FLAGS 1
#endif
#ifndef HAS_SOCKLEN_T
#define HAS_SOCKLEN_T 1
#endif
#ifndef HAS_GETADDRINFO
#define HAS_GETADDRINFO 1
#endif
#ifndef HAS_GETNAMEINFO
#define HAS_GETNAMEINFO 1
#endif
#elif defined(__vita__)
#ifdef HAS_POLL
#undef HAS_POLL
#endif
#ifdef HAS_FCNTL
#undef HAS_FCNTL
#endif
#ifdef HAS_IOCTL
#undef HAS_IOCTL
#endif
#ifndef HAS_INET_PTON
#define HAS_INET_PTON 1
#endif
#ifndef HAS_INET_NTOP
#define HAS_INET_NTOP 1
#endif
#ifdef HAS_MSGHDR_FLAGS
#undef HAS_MSGHDR_FLAGS
#endif
#ifndef HAS_SOCKLEN_T
#define HAS_SOCKLEN_T 1
#endif
#ifndef HAS_GETADDRINFO
#define HAS_GETADDRINFO 1
#endif
#ifndef HAS_GETNAMEINFO
#define HAS_GETNAMEINFO 1
#endif
#elif defined(__WIIU__)
#ifndef HAS_POLL
#define HAS_POLL 1
#endif
#ifndef HAS_FCNTL
#define HAS_FCNTL 1
#endif
#ifndef HAS_IOCTL
#define HAS_IOCTL 1
#endif
#ifndef HAS_INET_PTON
#define HAS_INET_PTON 1
#endif
#ifndef HAS_INET_NTOP
#define HAS_INET_NTOP 1
#endif
#ifndef HAS_SOCKLEN_T
#define HAS_SOCKLEN_T 1
#endif
#ifndef HAS_GETADDRINFO
#define HAS_GETADDRINFO 1
#endif
#ifndef HAS_GETNAMEINFO
#define HAS_GETNAMEINFO 1
#endif
#ifndef NO_MSGAPI
#define NO_MSGAPI 1
#endif
#elif defined(__3DS__)
#ifdef AF_INET6
#undef AF_INET6
#endif
#ifndef HAS_POLL
#define HAS_POLL 1
#endif
#ifndef HAS_FCNTL
#define HAS_FCNTL 1
#endif
#ifndef HAS_IOCTL
#define HAS_IOCTL 1
#endif
#ifndef HAS_INET_PTON
#define HAS_INET_PTON 1
#endif
#ifndef HAS_INET_NTOP
#define HAS_INET_NTOP 1
#endif
#ifndef HAS_SOCKLEN_T
#define HAS_SOCKLEN_T 1
#endif
#ifndef HAS_GETADDRINFO
#define HAS_GETADDRINFO 1
#endif
#ifndef HAS_GETNAMEINFO
#define HAS_GETNAMEINFO 1
#endif
#ifndef NO_MSGAPI
#define NO_MSGAPI 1
#endif
#elif defined(__HAIKU__)
#ifndef HAS_POLL
#define HAS_POLL 1
#endif
#else
#ifndef HAS_IOCTL
#define HAS_IOCTL 1
#endif
#ifndef HAS_POLL
#define HAS_POLL 1
#endif
#endif

#ifdef HAS_FCNTL
#include <fcntl.h>
#endif

#ifdef HAS_IOCTL
#include <sys/ioctl.h>
#endif

#ifdef HAS_POLL
#include <poll.h>
#endif

#if !defined(HAS_SOCKLEN_T) && !defined(__socklen_t_defined) && !defined(__HAIKU__)
typedef int socklen_t;
#endif

#ifndef SOMAXCONN
#define SOMAXCONN 128
#endif

#ifndef MSG_NOSIGNAL
#define MSG_NOSIGNAL 0
#endif

static enet_uint32 timeBase = 0;

int
enet_initialize (void)
{
    return 0;
}

void
enet_deinitialize (void)
{
}

enet_uint32
enet_host_random_seed (void)
{
    struct timeval timeVal;

    gettimeofday (& timeVal, NULL);

    return (timeVal.tv_sec * 1000) ^ (timeVal.tv_usec / 1000);
}

enet_uint32
enet_time_get (void)
{
    struct timeval timeVal;

    gettimeofday (& timeVal, NULL);

    return timeVal.tv_sec * 1000 + timeVal.tv_usec / 1000 - timeBase;
}

void
enet_time_set (enet_uint32 newTimeBase)
{
    struct timeval timeVal;

    gettimeofday (& timeVal, NULL);

    timeBase = timeVal.tv_sec * 1000 + timeVal.tv_usec / 1000 - newTimeBase;
}

#ifdef __APPLE__
void
enet_address_make_v4mapped (ENetAddress * address)
{
    ENetAddress oldAddress = *address;
    struct sockaddr_in *sin = ((struct sockaddr_in *)&oldAddress.address);
    struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&address->address;

    memset(sin6, 0, sizeof(*sin6));
    sin6->sin6_family = AF_INET6;
    sin6->sin6_len = sizeof(*sin6);
    sin6->sin6_port = sin->sin_port;

    sin6->sin6_addr.s6_addr[10] = 0xFF;
    sin6->sin6_addr.s6_addr[11] = 0xFF;
    memcpy(&sin6->sin6_addr.s6_addr[12], &sin->sin_addr, 4);

    address->addressLength = sizeof(*sin6);
}
#endif

int
enet_address_equal (ENetAddress * address1, ENetAddress * address2)
{
    if (address1 -> address.ss_family != address2 -> address.ss_family)
      return 0;

    switch (address1 -> address.ss_family)
    {
    case AF_INET:
    {
        struct sockaddr_in *sin1, *sin2;
        sin1 = (struct sockaddr_in *) & address1 -> address;
        sin2 = (struct sockaddr_in *) & address2 -> address;
        return sin1 -> sin_port == sin2 -> sin_port &&
            sin1 -> sin_addr.s_addr == sin2 -> sin_addr.s_addr;
    }
#ifdef AF_INET6
    case AF_INET6:
    {
        struct sockaddr_in6 *sin6a, *sin6b;
        sin6a = (struct sockaddr_in6 *) & address1 -> address;
        sin6b = (struct sockaddr_in6 *) & address2 -> address;
        return sin6a -> sin6_port == sin6b -> sin6_port &&
            ! memcmp (& sin6a -> sin6_addr, & sin6b -> sin6_addr, sizeof (sin6a -> sin6_addr));
    }
#endif
    default:
    {
        return 0;
    }
    }
}

int
enet_address_set_port (ENetAddress * address, enet_uint16 port)
{
    if (address -> address.ss_family == AF_INET)
    {
        struct sockaddr_in *sin = (struct sockaddr_in *) &address -> address;
        sin -> sin_port = ENET_HOST_TO_NET_16 (port);
        return 0;
    }
#ifdef AF_INET6
    else if (address -> address.ss_family == AF_INET6)
    {
        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &address -> address;
        sin6 -> sin6_port = ENET_HOST_TO_NET_16 (port);
        return 0;
    }
#endif
    else
    {
        return -1;
    }
}

int
enet_address_set_address (ENetAddress * address, struct sockaddr * addr, socklen_t addrlen)
{
    if (addrlen > sizeof(struct sockaddr_storage))
      return -1;

    memcpy (&address->address, addr, addrlen);
    address->addressLength = addrlen;
    return 0;
}

int
enet_address_set_host (ENetAddress * address, const char * name)
{
    struct addrinfo hints, * resultList = NULL, * result = NULL;

    memset (& hints, 0, sizeof (hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_flags = AI_ADDRCONFIG;

    if (getaddrinfo (name, NULL, & hints, & resultList) != 0)
      return -1;

    for (result = resultList; result != NULL; result = result -> ai_next)
    {
        memcpy (& address -> address, result -> ai_addr, result -> ai_addrlen);
        address -> addressLength = result -> ai_addrlen;

        freeaddrinfo (resultList);

        return 0;
    }

    if (resultList != NULL)
      freeaddrinfo (resultList);

    return -1;
}

int
enet_socket_bind (ENetSocket socket, const ENetAddress * address)
{
    return bind (socket,
        (struct sockaddr *) & address -> address,
        address -> addressLength);
}

int
enet_socket_get_address (ENetSocket socket, ENetAddress * address)
{
    address -> addressLength = sizeof (address -> address);

    if (getsockname (socket, (struct sockaddr *) & address -> address, & address -> addressLength) == -1)
      return -1;

    return 0;
}

int
enet_socket_listen (ENetSocket socket, int backlog)
{
    return listen (socket, backlog < 0 ? SOMAXCONN : backlog);
}

ENetSocket
enet_socket_create (int af, ENetSocketType type)
{
    ENetSocket sock = socket (af, type == ENET_SOCKET_TYPE_DATAGRAM ? SOCK_DGRAM : SOCK_STREAM, 0);
    if (sock < 0) {
        return sock;
    }

#ifdef IPV6_V6ONLY
    if (af == AF_INET6) {
        int off = 0;

        // Some OSes don't support dual-stack sockets, so ignore failures
        setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&off, sizeof(off));
    }
#endif

#ifdef IP_PKTINFO
    {
        // We turn this on for all sockets because it may be required for IPv4
        // traffic on dual-stack sockets on some OSes.
        int on = 1;
        setsockopt(sock, IPPROTO_IP, IP_PKTINFO, (char *)&on, sizeof(on));
    }
#endif

#ifdef IPV6_RECVPKTINFO
    if (af == AF_INET6) {
        int on = 1;
        setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, (char *)&on, sizeof(on));
    }
#endif

#ifdef __WIIU__
    {
        // Enable usage of userbuffers on Wii U
        int on = 1;
        setsockopt(sock, SOL_SOCKET, SO_RUSRBUF, (char *)&on, sizeof(on));
    }
#endif

    return sock;
}

int
enet_socket_set_option (ENetSocket socket, ENetSocketOption option, int value)
{
    int result = -1;
    switch (option)
    {
        case ENET_SOCKOPT_NONBLOCK:
#ifdef HAS_FCNTL
            result = fcntl (socket, F_SETFL, (value ? O_NONBLOCK : 0) | (fcntl (socket, F_GETFL) & ~O_NONBLOCK));
#else
#ifdef HAS_IOCTL
            result = ioctl (socket, FIONBIO, & value);
#else
            result = setsockopt (socket, SOL_SOCKET, SO_NONBLOCK, (char *) & value, sizeof(int));
#endif
#endif
            break;

        case ENET_SOCKOPT_REUSEADDR:
            result = setsockopt (socket, SOL_SOCKET, SO_REUSEADDR, (char *) & value, sizeof (int));
            break;

        case ENET_SOCKOPT_RCVBUF:
            result = setsockopt (socket, SOL_SOCKET, SO_RCVBUF, (char *) & value, sizeof (int));
            break;

        case ENET_SOCKOPT_SNDBUF:
            result = setsockopt (socket, SOL_SOCKET, SO_SNDBUF, (char *) & value, sizeof (int));
            break;

#if !defined(__WIIU__) && !defined(__3DS__)
        case ENET_SOCKOPT_RCVTIMEO:
        {
            struct timeval timeVal;
            timeVal.tv_sec = value / 1000;
            timeVal.tv_usec = (value % 1000) * 1000;
            result = setsockopt (socket, SOL_SOCKET, SO_RCVTIMEO, (char *) & timeVal, sizeof (struct timeval));
            break;
        }

        case ENET_SOCKOPT_SNDTIMEO:
        {
            struct timeval timeVal;
            timeVal.tv_sec = value / 1000;
            timeVal.tv_usec = (value % 1000) * 1000;
            result = setsockopt (socket, SOL_SOCKET, SO_SNDTIMEO, (char *) & timeVal, sizeof (struct timeval));
            break;
        }
#endif

        case ENET_SOCKOPT_NODELAY:
            result = setsockopt (socket, IPPROTO_TCP, TCP_NODELAY, (char *) & value, sizeof (int));
            break;

        case ENET_SOCKOPT_QOS:
#ifdef SO_NET_SERVICE_TYPE
            // iOS/macOS
            value = value ? NET_SERVICE_TYPE_VO : NET_SERVICE_TYPE_BE;
            result = setsockopt (socket, SOL_SOCKET, SO_NET_SERVICE_TYPE, (char *) & value, sizeof (int));
#endif
#ifdef IP_TOS
            // UNIX - IPv4
            value = value ? (46 << 2 | 0x01) : 0; // DSCP: Expedited Forwarding + ECT(1) (L4S)
            result = setsockopt (socket, IPPROTO_IP, IP_TOS, (char *) & value, sizeof (int));
#endif
#ifdef IPV6_TCLASS
            // UNIX - IPv6
            value = value ? (46 << 2 | 0x01): 0; // DSCP: Expedited Forwarding + ECT(1) (L4S)
            result = setsockopt (socket, IPPROTO_IPV6, IPV6_TCLASS, (char *) & value, sizeof (int));
#endif
#ifdef SO_PRIORITY
            // Linux
            value = value ? 6 : 0; // Max priority without NET_CAP_ADMIN
            result = setsockopt (socket, SOL_SOCKET, SO_PRIORITY, (char *) & value, sizeof (int));
#endif
            break;

        case ENET_SOCKOPT_TTL:
            result = setsockopt (socket, IPPROTO_IP, IP_TTL, (char *) & value, sizeof (int));
            break;

        default:
            break;
    }
    return result == -1 ? -1 : 0;
}

int
enet_socket_get_option (ENetSocket socket, ENetSocketOption option, int * value)
{
    int result = -1;
    socklen_t len;
    switch (option)
    {
        case ENET_SOCKOPT_ERROR:
            len = sizeof (int);
            result = getsockopt (socket, SOL_SOCKET, SO_ERROR, value, & len);
            break;

        case ENET_SOCKOPT_TTL:
            len = sizeof (int);
            result = getsockopt (socket, IPPROTO_IP, IP_TTL, (char *) value, & len);
            break;

        default:
            break;
    }
    return result == -1 ? -1 : 0;
}

int
enet_socket_connect (ENetSocket socket, const ENetAddress * address)
{
    int result;

    result = connect (socket, (struct sockaddr *) & address -> address, address -> addressLength);
    if (result == -1 && errno == EINPROGRESS)
      return 0;

    return result;
}

ENetSocket
enet_socket_accept (ENetSocket socket, ENetAddress * address)
{
    int result;

    if (address != NULL)
      address -> addressLength = sizeof (address -> address);

    result = accept (socket,
                     address != NULL ? (struct sockaddr *) & address -> address : NULL,
                     address != NULL ? & address -> addressLength : NULL);

    if (result == -1)
      return ENET_SOCKET_NULL;

    return result;
}

int
enet_socket_shutdown (ENetSocket socket, ENetSocketShutdown how)
{
    return shutdown (socket, (int) how);
}

void
enet_socket_destroy (ENetSocket socket)
{
    if (socket != -1)
      close (socket);
}

int
enet_socket_send (ENetSocket socket,
                  const ENetAddress * peerAddress,
                  const ENetAddress * localAddress,
                  const ENetBuffer * buffers,
                  size_t bufferCount)
{
    int sentLength;

#ifdef NO_MSGAPI
    void* sendBuffer;
    size_t sendLength;

    if (bufferCount > 1)
    {
        size_t i;

        sendLength = 0;
        for (i = 0; i < bufferCount; i++)
        {
            sendLength += buffers[i].dataLength;
        }

        sendBuffer = malloc (sendLength);
        if (sendBuffer == NULL)
          return -1;

        sendLength = 0;
        for (i = 0; i < bufferCount; i++)
        {
            memcpy (& ((unsigned char *)sendBuffer)[sendLength], buffers[i].data, buffers[i].dataLength);
            sendLength += buffers[i].dataLength;
        }
    }
    else
    {
        sendBuffer = buffers[0].data;
        sendLength = buffers[0].dataLength;
    }

    sentLength = sendto (socket, sendBuffer, sendLength, MSG_NOSIGNAL,
        (struct sockaddr *) & peerAddress -> address, peerAddress -> addressLength);

    if (bufferCount > 1)
      free(sendBuffer);
#else
    struct msghdr msgHdr;
    char controlBufData[1024];

    memset (& msgHdr, 0, sizeof (struct msghdr));

    if (peerAddress != NULL)
    {
        msgHdr.msg_name = (void*) & peerAddress -> address;
        msgHdr.msg_namelen = peerAddress -> addressLength;
    }

    msgHdr.msg_iov = (struct iovec *) buffers;
    msgHdr.msg_iovlen = bufferCount;

    // We always send traffic from the same local address as we last received
    // from this peer to ensure it correctly recognizes our responses as
    // coming from the expected host.
    if (localAddress != NULL) {
#ifdef IP_PKTINFO
        if (localAddress->address.ss_family == AF_INET) {
            struct in_pktinfo pktInfo;

            pktInfo.ipi_spec_dst = ((struct sockaddr_in*)&localAddress->address)->sin_addr;
            pktInfo.ipi_ifindex = 0; // Unspecified

            msgHdr.msg_control = controlBufData;
            msgHdr.msg_controllen = CMSG_SPACE(sizeof(pktInfo));

            struct cmsghdr *chdr = CMSG_FIRSTHDR(&msgHdr);
            chdr->cmsg_level = IPPROTO_IP;
            chdr->cmsg_type = IP_PKTINFO;
            chdr->cmsg_len = CMSG_LEN(sizeof(pktInfo));
            memcpy(CMSG_DATA(chdr), &pktInfo, sizeof(pktInfo));
        }
#endif
#ifdef IPV6_PKTINFO
        if (localAddress->address.ss_family == AF_INET6) {
            struct in6_pktinfo pktInfo;

            pktInfo.ipi6_addr = ((struct sockaddr_in6*)&localAddress->address)->sin6_addr;
            pktInfo.ipi6_ifindex = 0; // Unspecified

            msgHdr.msg_control = controlBufData;
            msgHdr.msg_controllen = CMSG_SPACE(sizeof(pktInfo));

            struct cmsghdr *chdr = CMSG_FIRSTHDR(&msgHdr);
            chdr->cmsg_level = IPPROTO_IPV6;
            chdr->cmsg_type = IPV6_PKTINFO;
            chdr->cmsg_len = CMSG_LEN(sizeof(pktInfo));
            memcpy(CMSG_DATA(chdr), &pktInfo, sizeof(pktInfo));
        }
 #endif
    }

    sentLength = sendmsg (socket, & msgHdr, MSG_NOSIGNAL);
#endif

    if (sentLength == -1)
    {
        switch (errno)
        {
        case EWOULDBLOCK:
            return 0;

        // These errors are treated as possible transient
        // conditions that could be caused by a network
        // interruption. We'll ignore them and allow the
        // socket timeout to kill us if the connection
        // is permanently interrupted.
        case EADDRNOTAVAIL:
        case ENETDOWN:
        case ENETUNREACH:
        case EHOSTDOWN:
        case EHOSTUNREACH:
            return 0;

        default:
            return -1;
        }
    }

    return sentLength;
}

int
enet_socket_receive (ENetSocket socket,
                     ENetAddress * peerAddress,
                     ENetAddress * localAddress,
                     ENetBuffer * buffers,
                     size_t bufferCount)
{
    int recvLength;

#ifdef NO_MSGAPI
    // This will ONLY work with a single buffer!

    peerAddress -> addressLength = sizeof (peerAddress -> address);
    recvLength = recvfrom (socket, buffers[0].data, buffers[0].dataLength, MSG_NOSIGNAL,
        (struct sockaddr *) & peerAddress -> address, & peerAddress -> addressLength);

    if (recvLength == -1)
    {
       if (errno == EWOULDBLOCK)
         return 0;

       return -1;
    }

    return recvLength;
#else
    struct msghdr msgHdr;
    char controlBufData[1024];

    memset (& msgHdr, 0, sizeof (struct msghdr));

    if (peerAddress != NULL)
    {
        msgHdr.msg_name = & peerAddress -> address;
        msgHdr.msg_namelen = sizeof (peerAddress -> address);
    }

    msgHdr.msg_iov = (struct iovec *) buffers;
    msgHdr.msg_iovlen = bufferCount;
    msgHdr.msg_control = controlBufData;
    msgHdr.msg_controllen = sizeof(controlBufData);

    recvLength = recvmsg (socket, & msgHdr, MSG_NOSIGNAL);

    if (recvLength == -1)
    {
       if (errno == EWOULDBLOCK)
         return 0;

       return -1;
    }

#ifdef HAS_MSGHDR_FLAGS
    if (msgHdr.msg_flags & MSG_TRUNC)
      return -2;
#endif

    // Retrieve the local address that this traffic was received on
    // to ensure we respond from the correct address/interface.
    if (localAddress != NULL) {
        for (struct cmsghdr *chdr = CMSG_FIRSTHDR(&msgHdr); chdr != NULL; chdr = CMSG_NXTHDR(&msgHdr, chdr)) {
#ifdef IP_PKTINFO
            if (chdr->cmsg_level == IPPROTO_IP && chdr->cmsg_type == IP_PKTINFO) {
                struct sockaddr_in *localAddr = (struct sockaddr_in*)&localAddress->address;

                localAddr->sin_family = AF_INET;
                localAddr->sin_addr = ((struct in_pktinfo*)CMSG_DATA(chdr))->ipi_addr;

                localAddress->addressLength = sizeof(*localAddr);
                break;
            }
#endif
#ifdef IPV6_PKTINFO
            if (chdr->cmsg_level == IPPROTO_IPV6 && chdr->cmsg_type == IPV6_PKTINFO) {
                struct sockaddr_in6 *localAddr = (struct sockaddr_in6*)&localAddress->address;

                localAddr->sin6_family = AF_INET6;
                localAddr->sin6_addr = ((struct in6_pktinfo*)CMSG_DATA(chdr))->ipi6_addr;

                localAddress->addressLength = sizeof(*localAddr);
                break;
            }
 #endif
        }
    }

    if (peerAddress != NULL) {
        peerAddress -> addressLength = msgHdr.msg_namelen;

#ifdef __APPLE__
        // HACK: Apple platforms return AF_INET addresses in msg_name from recvmsg() on dual-stack sockets
        // instead of AF_INET6 addresses then rejects those same addresses when they are passed to sendmsg().
        // Strangely, this only happens when the socket is bound, and IPV6_PKTINFO properly returns v4-mapped
        // addresses in the same call. This is probably a kernel bug, so we fix it up here.
        if (peerAddress -> address.ss_family == AF_INET && localAddress -> address.ss_family == AF_INET6) {
            enet_address_make_v4mapped(peerAddress);
        }
#endif
    }

    return recvLength;
#endif
}

int
enet_socketset_select (ENetSocket maxSocket, ENetSocketSet * readSet, ENetSocketSet * writeSet, enet_uint32 timeout)
{
    struct timeval timeVal;

    timeVal.tv_sec = timeout / 1000;
    timeVal.tv_usec = (timeout % 1000) * 1000;

    return select (maxSocket + 1, readSet, writeSet, NULL, & timeVal);
}

int
enet_socket_wait (ENetSocket socket, enet_uint32 * condition, enet_uint32 timeout)
{
#ifdef HAS_POLL
    struct pollfd pollSocket;
    int pollCount;

    pollSocket.fd = socket;
    pollSocket.events = 0;

    if (* condition & ENET_SOCKET_WAIT_SEND)
      pollSocket.events |= POLLOUT;

    if (* condition & ENET_SOCKET_WAIT_RECEIVE)
      pollSocket.events |= POLLIN;

#if defined(__3DS__)
    uint64_t poll_start = osGetTime();
    for (uint64_t i = poll_start; (i - poll_start) < timeout; i = osGetTime()) {
        pollCount = poll(& pollSocket, 1, 0); // need to do this on 3ds since poll will block even if socket is ready before
        if (pollCount) {
            break;
        }
        svcSleepThread(1000);
    }
#else
    pollCount = poll (& pollSocket, 1, timeout);
#endif

    if (pollCount < 0)
    {
        if (errno == EINTR && * condition & ENET_SOCKET_WAIT_INTERRUPT)
        {
            * condition = ENET_SOCKET_WAIT_INTERRUPT;

            return 0;
        }

        return -1;
    }

    * condition = ENET_SOCKET_WAIT_NONE;

    if (pollCount == 0)
      return 0;

    if (pollSocket.revents & POLLOUT)
      * condition |= ENET_SOCKET_WAIT_SEND;

    if (pollSocket.revents & POLLIN)
      * condition |= ENET_SOCKET_WAIT_RECEIVE;

    return 0;
#else
    fd_set readSet, writeSet;
    struct timeval timeVal;
    int selectCount;

    timeVal.tv_sec = timeout / 1000;
    timeVal.tv_usec = (timeout % 1000) * 1000;

    FD_ZERO (& readSet);
    FD_ZERO (& writeSet);

    if (* condition & ENET_SOCKET_WAIT_SEND)
      FD_SET (socket, & writeSet);

    if (* condition & ENET_SOCKET_WAIT_RECEIVE)
      FD_SET (socket, & readSet);

    selectCount = select (socket + 1, & readSet, & writeSet, NULL, & timeVal);

    if (selectCount < 0)
    {
        if (errno == EINTR && * condition & ENET_SOCKET_WAIT_INTERRUPT)
        {
            * condition = ENET_SOCKET_WAIT_INTERRUPT;

            return 0;
        }

        return -1;
    }

    * condition = ENET_SOCKET_WAIT_NONE;

    if (selectCount == 0)
      return 0;

    if (FD_ISSET (socket, & writeSet))
      * condition |= ENET_SOCKET_WAIT_SEND;

    if (FD_ISSET (socket, & readSet))
      * condition |= ENET_SOCKET_WAIT_RECEIVE;

    return 0;
#endif
}

#endif