path: root/dep/g3dlite/source/NetworkDevice.cpp

/**
 @file NetworkDevice.cpp

 @maintainer Morgan McGuire, morgan@cs.brown.edu
 @created 2002-11-22
 @edited  2006-02-24
 */

#include "G3D/platform.h"
#include "G3D/TextOutput.h"
#include "G3D/NetworkDevice.h"
#include "G3D/NetAddress.h"
#include "G3D/BinaryInput.h"
#include "G3D/BinaryOutput.h"
#include "G3D/Log.h"
#include "G3D/G3DGameUnits.h"
#include "G3D/stringutils.h"
#include "G3D/debug.h"
#include "G3D/networkHelpers.h"


namespace G3D {

NetworkDevice* NetworkDevice::s_instance = NULL;

std::ostream& operator<<(std::ostream& os, const NetAddress& a) {
    return os << a.toString();
}


static void logSocketInfo(const SOCKET& sock) {
    uint32 val;
    socklen_t sz = 4;
    int ret;

    ret = getsockopt(sock, SOL_SOCKET, SO_RCVBUF, (char*)&val, (socklen_t*)&sz);
    logPrintf("SOL_SOCKET/SO_RCVBUF = %d\n", val);

    ret = getsockopt(sock, SOL_SOCKET, SO_SNDBUF, (char*)&val, (socklen_t*)&sz);
    logPrintf("SOL_SOCKET/SO_SNDBUF = %d\n", val);

    // Note: timeout = 0 means no timeout
    ret = getsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, (char*)&val, (socklen_t*)&sz);
    logPrintf("SOL_SOCKET/SO_RCVTIMEO = %d\n", val);

    ret = getsockopt(sock, SOL_SOCKET, SO_SNDTIMEO, (char*)&val, (socklen_t*)&sz);
    logPrintf("SOL_SOCKET/SO_SNDTIMEO = %d\n", val);
}


/////////////////////////////////////////////////////////////////////////////

/** Invokes select on one socket.  Returns SOCKET_ERROR on error, 0 if
    there is no read pending, sock if there a read pending. */
static int selectOneReadSocket(const SOCKET& sock) {
    // 0 time timeout is specified to poll and return immediately
    struct timeval timeout;
    timeout.tv_sec  = 0;
    timeout.tv_usec = 0;

    // Create a set that contains just this one socket
    fd_set socketSet;
    FD_ZERO(&socketSet); 
    FD_SET(sock, &socketSet);

    int ret = select(sock + 1, &socketSet, NULL, NULL, &timeout);

    return ret;
}


/** Returns true if the socket has a read pending */
static bool readWaiting(const SOCKET& sock) {
    int ret = selectOneReadSocket(sock);

    switch (ret) {
    case SOCKET_ERROR:
        logPrintf("ERROR: selectOneReadSocket returned "
                  "SOCKET_ERROR in readWaiting(). %s", socketErrorCode().c_str());
        // Return true so that we'll force an error on read and close
        // the socket.
        return true;

    case 0:
        return false;

    default:
        return true;
    }
}


/** Invokes select on one socket.   */
static int selectOneWriteSocket(const SOCKET& sock) {
    // 0 time timeout is specified to poll and return immediately
    struct timeval timeout;
    timeout.tv_sec  = 0;
    timeout.tv_usec = 0;

    // Create a set that contains just this one socket
    fd_set socketSet;
    FD_ZERO(&socketSet); 
    FD_SET(sock, &socketSet);

    return select(sock + 1, NULL, &socketSet, NULL, &timeout);
}

///////////////////////////////////////////////////////////////////////////////

NetworkDevice* NetworkDevice::instance() {
    if (s_instance == NULL) {
        s_instance = new NetworkDevice();
        if (! s_instance->init()) {
            delete s_instance;
            s_instance = NULL;
        }
    }
    return s_instance;
}


void NetworkDevice::cleanup() {
    if (s_instance) {
        s_instance->_cleanup();
        delete s_instance;
        s_instance = NULL;
    }
}


NetworkDevice::NetworkDevice() {
    initialized  = false;
}


NetworkDevice::~NetworkDevice() {
}


std::string NetworkDevice::localHostName() const {   
    char ac[128];
    if (gethostname(ac, sizeof(ac)) == -1) {
        Log::common()->printf("Error while getting local host name\n");
        return "localhost";
    }
    return gethostbyname(ac)->h_name;
}

#ifndef G3D_WIN32
const char* errnoToString() {
    switch (errno) {
    case EBADF:
        return "file descriptor is invalid.";

    case EINVAL: 
        return "Request or argp is not valid.";
        
    case ENOTTY:
        return 
            "file descriptor is not associated with a character special device OR "
            "The specified request does not apply to the "
            "kind of object that the descriptor fildes references.";

    case EADDRNOTAVAIL:
        return "Address not available.";

    default:
        {
            static char buffer[20];
            sprintf(buffer, "Error %d", errno);
            return buffer;
        }
    }
}
#endif


NetworkDevice::EthernetAdapter::EthernetAdapter() {
    name = "";
    ip = 0;
    hostname = "";
    subnet = 0;
    broadcast = 0;
    for (int i = 0; i < 6; ++i) {
        mac[i] = 0;
    }
}

void NetworkDevice::EthernetAdapter::describe(TextOutput& t) const {
    t.writeSymbol("{");
    t.pushIndent();
    t.writeNewline();
    
    t.writeSymbols("hostname", "=");
    t.writeString(hostname);
    t.writeNewline();

    t.writeSymbols("name", "=");
    t.writeString(name);
    t.writeNewline();    

    t.writeSymbols("ip", "=");
    t.writeSymbol(formatIP(ip));
    t.writeNewline();    

    t.writeSymbols("subnet", "=");
    t.writeSymbol(formatIP(subnet));
    t.writeNewline();    

    t.writeSymbols("broadcast", "=");
    t.writeSymbol(formatIP(broadcast));
    t.writeNewline();    

    t.writeSymbols("mac", "=");
    t.writeSymbol(formatMAC(mac));
    t.writeNewline();    

    t.popIndent();
    t.writeSymbol("}");
    t.writeNewline();
}


void NetworkDevice::addAdapter(const EthernetAdapter& a) {
    m_adapterArray.append(a);
    if (a.broadcast != 0) {
        int i = m_broadcastAddresses.findIndex(a.broadcast);
        if (i == -1) {
            m_broadcastAddresses.append(a.broadcast);
        }
    }
}


std::string NetworkDevice::formatIP(uint32 addr) {
    return format("%3d.%3d.%3d.%3d", (addr >> 24) & 0xFF, (addr >> 16) & 0xFF,
           (addr >> 8) & 0xFF, addr & 0xFF);
}


std::string NetworkDevice::formatMAC(const uint8 MAC[6]) {
    return format("%02x:%02x:%02x:%02x:%02x:%02x", MAC[0], MAC[1], MAC[2], MAC[3], MAC[4], MAC[5]);
}


#ifdef G3D_WIN32

bool NetworkDevice::init() {
    debugAssert(! initialized);

    logPrintf("Network Startup");
    logPrintf("Starting WinSock networking.\n");
    WSADATA wsda;		    
    WSAStartup(MAKEWORD(G3D_WINSOCK_MAJOR_VERSION, G3D_WINSOCK_MINOR_VERSION), &wsda);
        
    std::string hostname = "localhost";
    {
        char ac[128];
        if (gethostname(ac, sizeof(ac)) == -1) {
            logPrintf("Warning: Error while getting local host name\n");
        } else {
            hostname = gethostbyname(ac)->h_name;
        }
    }
    
    EthernetAdapter a;
    a.hostname = hostname;
    a.name = "";
    a.ip = NetAddress(hostname, 0).ip();

    // TODO: Find subnet on Win32
    a.subnet = 0x0000FFFF;
    
    // TODO: Find broadcast on Win32
    a.broadcast = 0xFFFFFFFF;

    // TODO: find MAC on Win32
    
    addAdapter(a);
    
    std::string machine = localHostName();
    std::string addr    = NetAddress(machine, 0).ipString();
    logPrintf(
              "Network:\n"
              "  Status: %s\n"
              "  Loaded winsock specification version %d (%d is "
              "the highest available)\n"
              "  %d sockets available\n"
              "  Largest UDP datagram packet size is %d bytes\n\n",
              wsda.szDescription,
              wsda.szSystemStatus,
              wsda.wVersion,
              wsda.wHighVersion,
              wsda.iMaxSockets,
              wsda.iMaxUdpDg);
    
    // TODO: WSAIoctl for subnet and broadcast addresses
    // http://msdn.microsoft.com/en-us/library/ms741621(VS.85).aspx
    // 
    // TODO: SIO_GET_INTERFACE_LIST 

    initialized = true;

    return true;
}
#endif


#if defined(G3D_LINUX) || defined(G3D_OSX) || defined(G3D_FREEBSD)

const sockaddr_in* castToIP4(const sockaddr* addr) {
    if (addr == NULL) {
        return NULL;
    } else if (addr->sa_family == AF_INET) {
        // An IPv4 address
        return reinterpret_cast<const sockaddr_in*>(addr);
    } else {
        // Not an IPv4 address
        return NULL;
    }
}

uint32 getIP(const sockaddr_in* addr) {
    if (addr != NULL) {
        return ntohl(addr->sin_addr.s_addr);
    } else {
        return 0;
    }
}


bool NetworkDevice::init() {
    debugAssert(! initialized);

    // Used for combining the MAC and ip information
    typedef Table<std::string, EthernetAdapter> AdapterTable;

    AdapterTable table;

    // Head of a linked list of network interfaces on this machine
    ifaddrs* ifap = NULL;

    int r = getifaddrs(&ifap);

    if (r != 0) {
        logPrintf("ERROR: getifaddrs returned %d\n", r);
        return false;
    }

    ifaddrs* current = ifap;

    if (current == NULL) {
        logPrintf("WARNING: No network interfaces found\n");
        EthernetAdapter a;
        a.name = "fallback";
        a.hostname = "localhost";
        a.ip = (127 << 24) | 1;       
        a.broadcast = 0xFFFFFFFF;
        a.subnet    = 0x000000FF;
        addAdapter(a);

    } else {

        while (current != NULL) {

            bool up = (current->ifa_flags & IFF_UP); 
            bool loopback = (current->ifa_flags & IFF_LOOPBACK);

            if (! up || loopback) {
                // Skip this adapter; it is offline or is a loopback
                current = current->ifa_next;
                continue;
            }

            if (! table.containsKey(current->ifa_name)) {
                EthernetAdapter a;
                a.name = current->ifa_name;
                table.set(a.name, a);
            }

            // This adapter must exist because it was created above
            EthernetAdapter& adapter = table[current->ifa_name];

            const sockaddr_in* interfaceAddress = castToIP4(current->ifa_addr);
            const sockaddr_in* broadcastAddress = castToIP4(current->ifa_dstaddr);
            const sockaddr_in* subnetMask       = castToIP4(current->ifa_netmask);

            uint32 ip = getIP(interfaceAddress);
            uint32 ba = getIP(broadcastAddress);
            uint32 sn = getIP(subnetMask);
            
            if (ip != 0) {
                adapter.ip = ip;
            }

            if (ba != 0) {
                adapter.broadcast = ba;
            }

            if (sn != 0) {
                adapter.subnet = sn;
            }

            uint8_t* MAC = NULL;
            // Extract MAC address
            if ((current->ifa_addr != NULL) && (current->ifa_addr->sa_family == AF_LINK)) {
#               ifdef __linux__
                {
                    // Linux
                    struct ifreq ifr;
                    
                    int fd = socket(AF_INET, SOCK_DGRAM, 0);
                    
                    ifr.ifr_addr.sa_family = AF_INET;
                    strcpy(ifr.ifr_name, current->ifa_name);
                    ioctl(fd, SIOCGIFHWADDR, &ifr);
                    close(fd);
                    
                    MAC = reinterpret_cast<uint8_t*>(ifr.ifr_hwaddr.sa_data);
                }
#               else
                {
                    // The MAC address and the interfaceAddress come in as
                    // different interfaces with the same name.
                    
                    // Posix/FreeBSD/Mac OS
                    sockaddr_dl* sdl = (struct sockaddr_dl *)current->ifa_addr;
                    MAC = reinterpret_cast<uint8_t*>(LLADDR(sdl));
                }
#               endif
                
                // See if there was a MAC address
                if (MAC != NULL) {
                    bool anyNonZero = false;
                    for (int i = 0; i < 6; ++i) {
                        anyNonZero = anyNonZero || (MAC[i] != 0);
                    }
                    if (anyNonZero) {
                        System::memcpy(adapter.mac, MAC, 6);
                    }
                }
            }
     
            current = current->ifa_next;
        }

        freeifaddrs(ifap);
        ifap = NULL;
    }

    // Extract all interesting adapters from the table
    for (AdapterTable::Iterator it = table.begin(); it.hasMore(); ++it) {
        const EthernetAdapter& adapter = it->value;
        
        // Only add adapters that have IP addresses
        if (adapter.ip != 0) {
            addAdapter(adapter);
        } else {
            logPrintf("NetworkDevice: Ignored adapter %s because ip = 0\n", adapter.name.c_str());
        }
    }

    initialized = true;

    return true;
}

#endif


void NetworkDevice::_cleanup() {
    debugAssert(initialized);

    logPrintf("Network Cleanup");
#   ifdef G3D_WIN32
        WSACleanup();
#   endif
    logPrintf("Network cleaned up.");
}

bool NetworkDevice::bind(SOCKET sock, const NetAddress& addr) const {
    Log::common()->printf("Binding socket %d on port %d ", 
                     sock, htons(addr.addr.sin_port));
    if (::bind(sock, (struct sockaddr*)&(addr.addr), sizeof(addr.addr)) == 
        SOCKET_ERROR) {

        Log::common()->println("FAIL");
        Log::common()->println(socketErrorCode());
        closesocket(sock);
        return false;
    }

    Log::common()->println("Ok");
    return true;
}


void NetworkDevice::closesocket(SOCKET& sock) const {
    if (sock != 0) {
        #ifdef G3D_WIN32
            ::closesocket(sock);
        #else
            close(sock);
        #endif

        Log::common()->printf("Closed socket %d\n", sock);
        sock = 0;
    }
}


void NetworkDevice::localHostAddresses(Array<NetAddress>& array) const {
    array.resize(0);

    char ac[128];

    if (gethostname(ac, sizeof(ac)) == SOCKET_ERROR) {
        Log::common()->printf("Error while getting local host name\n");
        return;
    }

    struct hostent* phe = gethostbyname(ac);
    if (phe == 0) {
        Log::common()->printf("Error while getting local host address\n");
        return;
    }

    for (int i = 0; (phe->h_addr_list[i] != 0); ++i) {
        struct in_addr addr;
        memcpy(&addr, phe->h_addr_list[i], sizeof(struct in_addr));
        array.append(NetAddress(addr));
    }    
}

///////////////////////////////////////////////////////////////////////////////

Conduit::Conduit() : binaryOutput("<memory>", G3D_LITTLE_ENDIAN) {
    sock                = 0;
    mSent               = 0;
    mReceived           = 0;
    bSent               = 0;
    bReceived           = 0;
}


Conduit::~Conduit() {
    NetworkDevice::instance()->closesocket(sock);
}


uint64 Conduit::bytesSent() const {
    return bSent;
}


uint64 Conduit::bytesReceived() const {
    return bReceived;
}


uint64 Conduit::messagesSent() const {
    return mSent;
}


uint64 Conduit::messagesReceived() const {
    return mReceived;
}


bool Conduit::ok() const {
    return (sock != 0) && (sock != SOCKET_ERROR);
}


bool Conduit::messageWaiting() {
    return readWaiting(sock);
}


/**
 Increases the send and receive sizes of a socket to 2 MB from 8k
 */
static void increaseBufferSize(SOCKET sock) {

    // Increase the buffer size; the default (8192) is too easy to
    // overflow when the network latency is high.
    {
        uint32 val = 1024 * 1024 * 2;
        if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, 
                       (char*)&val, sizeof(val)) == SOCKET_ERROR) {
            Log::common()->printf("WARNING: Increasing socket "
                                 "receive buffer to %d failed.\n", val);
            Log::common()->println(socketErrorCode());
        }

        if (setsockopt(sock, SOL_SOCKET, SO_SNDBUF, 
                       (char*)&val, sizeof(val)) == SOCKET_ERROR) {
            Log::common()->printf("WARNING: Increasing socket "
                                 "send buffer to %d failed.\n", val);
            Log::common()->println(socketErrorCode());
        }
    }
}

//////////////////////////////////////////////////////////////////////////////

ReliableConduitRef ReliableConduit::create(const NetAddress& address) {
    return new ReliableConduit(address);
}


ReliableConduit::ReliableConduit(
    const NetAddress&   _addr) : state(NO_MESSAGE), receiveBuffer(NULL),
    receiveBufferTotalSize(0), receiveBufferUsedSize(0) {

    NetworkDevice* nd = NetworkDevice::instance();
    
    messageType         = 0;

    addr = _addr;
    Log::common()->print("Creating a TCP socket       ");
    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
    
    if (sock == SOCKET_ERROR) {
        Log::common()->println("FAIL");
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
        return;
    }

    Log::common()->println("Ok");

    // Setup socket options (both constructors should set the same options)

    // Disable Nagle's algorithm (we send lots of small packets)
    const int T = true;
    if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, 
                   (const char*)&T, sizeof(T)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Disabling Nagel's "
                              "algorithm failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Disabled Nagel's algorithm.");
    }

    // Set the NO LINGER option so the socket doesn't hang around if
    // there is unsent data in the queue when it closes.
    struct linger ling;
    ling.l_onoff  = 0;
    ling.l_linger = 0;
    if (setsockopt(sock, SOL_SOCKET, SO_LINGER, 
                   (const char*)&ling, sizeof(ling)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Setting socket no linger failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Set socket option no_linger.");
    }

    // Set reuse address so that a new server can start up soon after
    // an old one has closed.
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 
                   (const char*)&T, sizeof(T)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Setting socket reuseaddr failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Set socket option reuseaddr.");
    }

    // Ideally, we'd like to specify IPTOS_LOWDELAY as well.

    logSocketInfo(sock);

    increaseBufferSize(sock);

    Log::common()->printf("Created TCP socket %d\n", sock);

    std::string x = addr.toString();
    Log::common()->printf("Connecting to %s on TCP socket %d   ", x.c_str(), sock);

    int ret = connect(sock, (struct sockaddr *) &(addr.addr), sizeof(addr.addr));

    if (ret == WSAEWOULDBLOCK) {
        RealTime t = System::time() + 5.0;
        // Non-blocking; we must wait until select returns non-zero
        while ((selectOneWriteSocket(sock) == 0) && (System::time() < t)) {
            System::sleep(0.02);
        }

        // TODO: check for failure on the select call

    } else if (ret != 0) {
        sock = (SOCKET)SOCKET_ERROR;
        Log::common()->println("FAIL");
        Log::common()->println(socketErrorCode());
        return;
    }

    Log::common()->println("Ok");
}


ReliableConduit::ReliableConduit(
    const SOCKET&      _sock, 
    const NetAddress&  _addr) : 
    state(NO_MESSAGE), 
    receiveBuffer(NULL), 
    receiveBufferTotalSize(0), 
    receiveBufferUsedSize(0) {
    sock                = _sock;
    addr                = _addr;

    messageType         = 0;

    // Setup socket options (both constructors should set the same options)

    // Disable Nagle's algorithm (we send lots of small packets)
    const int T = true;
    if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, 
                   (const char*)&T, sizeof(T)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Disabling Nagel's algorithm failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Disabled Nagel's algorithm.");
    }

    // Set the NO LINGER option so the socket doesn't hang around if
    // there is unsent data in the queue when it closes.
    struct linger ling;
    ling.l_onoff  = 0;
    ling.l_linger = 0;
    if (setsockopt(sock, SOL_SOCKET, SO_LINGER, 
                   (const char*)&ling, sizeof(ling)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Setting socket no linger failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Set socket option no_linger.");
    }

    // Set reuse address so that a new server can start up soon after
    // an old one has closed.
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 
                   (const char*)&T, sizeof(T)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Setting socket reuseaddr failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Set socket option reuseaddr.");
    }

    // Ideally, we'd like to specify IPTOS_LOWDELAY as well.

    logSocketInfo(sock);
}


ReliableConduit::~ReliableConduit() {
    free(receiveBuffer);
    receiveBuffer = NULL;
    receiveBufferTotalSize = 0;
    receiveBufferUsedSize = 0;
}


bool ReliableConduit::messageWaiting() {
    switch (state) {
    case HOLDING:
        // We've already read the message and are waiting
        // for a receive call.
        return true;

    case RECEIVING:

        if (! ok()) {
            return false;
        }
        // We're currently receiving the message.  Read a little more.
        receiveIntoBuffer();
     
        if (messageSize == receiveBufferUsedSize) {
            // We've read the whole mesage.  Switch to holding state 
            // and return true.
            state = HOLDING;
            return true;
        } else {
            // There are more bytes left to read.  We'll read them on
            // the next call.  Because the *entire* message is not ready,
            // return false.
            return false;
        }
        break;

    case NO_MESSAGE:
        if (Conduit::messageWaiting()) {
            // Message incoming.  Read the header.

            state = RECEIVING;
            receiveHeader();
            
            // Loop back around now that we're in the receive state; we
            // may be able to read the whole message before returning 
            // to the caller.
            return messageWaiting();
        } else {
            // No message incoming.
            return false;
        }
    }

    debugAssertM(false, "Should not reach this point");
    return false;
}


uint32 ReliableConduit::waitingMessageType() {
    // The messageWaiting call is what actually receives the message.
    if (messageWaiting()) {
        return messageType;
    } else {
        return 0;
    }
}


void ReliableConduit::sendBuffer(const BinaryOutput& b) {
    NetworkDevice* nd = NetworkDevice::instance();
    int ret = ::send(sock, (const char*)b.getCArray(), b.size(), 0);
    
    if (ret == SOCKET_ERROR) {
        Log::common()->println("Error occured while sending message.");
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
        return;
    }

    ++mSent;
    bSent += b.size();

    // Verify the packet was actually sent
    // Conversion to unsigned is safe because -1 is caught earlier
    debugAssert(ret == b.size());
}


/** Null serializer.  Used by reliable conduit::send(type) */
class Dummy {
public:
    void serialize(BinaryOutput& b) const { (void)b; }
};


void ReliableConduit::send(uint32 type) {
    static Dummy dummy;
    send(type, dummy);
}



NetAddress ReliableConduit::address() const {
    return addr;
}


void ReliableConduit::receiveHeader() {
    NetworkDevice* nd = NetworkDevice::instance();
    debugAssert(state == RECEIVING);

    // Read the type
    uint32 tmp;
    int ret = recv(sock, (char*)&tmp, sizeof(tmp), 0);

    // The type is the first four bytes.  It is little endian.
    if (System::machineEndian() == G3D_LITTLE_ENDIAN) {
        messageType = tmp;
    } else {
        // Swap the byte order
        for (int i = 0; i < 4; ++i) {
            ((char*)&messageType)[i] = ((char*)&tmp)[3 - i];
        }
    }

    if ((ret == SOCKET_ERROR) || (ret != sizeof(messageType))) {
        Log::common()->printf("Call to recv failed.  ret = %d,"
                             " sizeof(messageType) = %d\n", 
                             (int)ret, (int)sizeof(messageType));
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
        messageType = 0;
        return;
    }

    // Read the size
    ret = recv(sock, (char*)&messageSize, sizeof(messageSize), 0);

    if ((ret == SOCKET_ERROR) || (ret != sizeof(messageSize))) {
        Log::common()->printf("Call to recv failed.  ret = %d,"
                             " sizeof(len) = %d\n", (int)ret,
                             (int)sizeof(messageSize));
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
        messageType = 0;
        return;
    }

    messageSize = ntohl(messageSize);
    debugAssert(messageSize < 6e7);

    debugAssert(receiveBufferUsedSize == 0);

    // Extend the size of the buffer.
    if (messageSize > receiveBufferTotalSize) {
        receiveBuffer = realloc(receiveBuffer, messageSize);
        receiveBufferTotalSize = messageSize;
    }

    if (receiveBuffer == NULL) {
        Log::common()->println("Could not allocate a memory buffer "
                              "during receivePacket.");
        nd->closesocket(sock);
    }

    bReceived += 4;
}


void ReliableConduit::receiveIntoBuffer() {
    NetworkDevice* nd = NetworkDevice::instance();

    debugAssert(state == RECEIVING);
    debugAssert(messageType != 0);
    debugAssertM(receiveBufferUsedSize < messageSize, "Message already received.");
    debugAssertM(messageSize >= receiveBufferUsedSize, "Message size overflow.");

    // Read the data itself
    int ret = 0;
    uint32 left = messageSize - receiveBufferUsedSize;
    int count = 0;
    while ((ret != SOCKET_ERROR) && (left > 0) && (count < 100)) {

        ret = recv(sock, ((char*)receiveBuffer) + receiveBufferUsedSize, left, 0);

        if (ret > 0) {
            left -= ret;
            receiveBufferUsedSize += ret;
            bReceived += ret;

            if (left > 0) {
                // There's still more. Give the machine a chance to read
                // more data, but don't wait forever.

                ++count;
                System::sleep(0.001);
            }
        } else {
            // Something went wrong; our blocking read returned nothing.
            break;
        }
    }

    if ((ret == 0) || (ret == SOCKET_ERROR)) {

        if (ret == SOCKET_ERROR) {
            Log::common()->printf("Call to recv failed.  ret = %d,"
                 " sizeof(messageSize) = %d\n", ret, messageSize);
            Log::common()->println(socketErrorCode());
        } else {
            Log::common()->printf("recv returned 0\n");
        }
        nd->closesocket(sock);
        return;
    }

    ++mReceived;
}


///////////////////////////////////////////////////////////////////////////////
LightweightConduitRef LightweightConduit::create(
    uint16                      receivePort,
    bool                        enableReceive,
    bool                        enableBroadcast) {
    
    return new LightweightConduit(receivePort, enableReceive, enableBroadcast);
}

LightweightConduit::LightweightConduit(
    uint16 port,
    bool enableReceive, 
    bool enableBroadcast) {
    NetworkDevice* nd = NetworkDevice::instance();

    Log::common()->print("Creating a UDP socket        ");
    sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    
    if (sock == SOCKET_ERROR) {
        sock = 0;
        Log::common()->println("FAIL");
        Log::common()->println(socketErrorCode());
        return;
    }
    Log::common()->println("Ok");

    if (enableReceive) {
        debugAssert(port != 0);
        if (! nd->bind(sock, NetAddress(0, port))) {
            nd->closesocket(sock);
            sock = (SOCKET)SOCKET_ERROR;
        }
    }

    // Figuring out the MTU seems very complicated, so we just set it to 1000,
    // which is likely to be safe.  See IP_MTU for more information.
    MTU = 1000;

    increaseBufferSize(sock);

    if (enableBroadcast) {
        int TR = true;
        if (setsockopt(sock, SOL_SOCKET, SO_BROADCAST, 
                       (const char*)&TR, sizeof(TR)) != 0) {
            Log::common()->println("Call to setsockopt failed");
            Log::common()->println(socketErrorCode());
            nd->closesocket(sock);
            sock = 0;
            return;
        }
    }

    Log::common()->printf("Done creating UDP socket %d\n", sock);

    alreadyReadMessage = false;
}


LightweightConduit::~LightweightConduit() {
}


bool LightweightConduit::receive(NetAddress& sender) {
    // This both checks to ensure that a message was waiting and
    // actively consumes the message from the network stream if
    // it has not been read yet.
    uint32 t = waitingMessageType();
    if (t == 0) {
        return false;
    }

    sender = messageSender;
    alreadyReadMessage = false;

    if (messageBuffer.size() < 4) {
        // Something went wrong
        return false;
    }

    return true;
}


void LightweightConduit::sendBuffer(const NetAddress& a, BinaryOutput& b) {
    NetworkDevice* nd = NetworkDevice::instance();
    if (sendto(sock, (const char*)b.getCArray(), b.size(), 0,
       (struct sockaddr *) &(a.addr), sizeof(a.addr)) == SOCKET_ERROR) {
        Log::common()->printf("Error occured while sending packet "
                             "to %s\n", inet_ntoa(a.addr.sin_addr));
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
    } else {
        ++mSent;
        bSent += b.size();
    }
}


bool LightweightConduit::messageWaiting() {
    // We may have already pulled the message off the network stream
    return alreadyReadMessage || Conduit::messageWaiting();
}


uint32 LightweightConduit::waitingMessageType() {
    NetworkDevice* nd = NetworkDevice::instance();
    if (! messageWaiting()) {
        return 0;
    } 

    if (! alreadyReadMessage) {
        messageBuffer.resize(8192);

        SOCKADDR_IN remote_addr;
        int iRemoteAddrLen = sizeof(sockaddr);

        int ret = recvfrom(sock, (char*)messageBuffer.getCArray(), 
            messageBuffer.size(), 0, (struct sockaddr *) &remote_addr, 
            (socklen_t*)&iRemoteAddrLen);

        if (ret == SOCKET_ERROR) {
            Log::common()->println("Error: recvfrom failed in "
                    "LightweightConduit::waitingMessageType().");
            Log::common()->println(socketErrorCode());
            nd->closesocket(sock);
            messageBuffer.resize(0);
            messageSender = NetAddress();
            messageType = 0;
            return 0;
        }

        messageSender = NetAddress(remote_addr);

        ++mReceived;
        bReceived += ret;

        messageBuffer.resize(ret, DONT_SHRINK_UNDERLYING_ARRAY);

        // The type is the first four bytes.  It is little endian.
        if (System::machineEndian() == G3D_LITTLE_ENDIAN) {
            messageType = *((uint32*)messageBuffer.getCArray());
        } else {
            // Swap the byte order
            for (int i = 0; i < 4; ++i) {
                ((char*)&messageType)[i] = messageBuffer[3 - i];
            }
        }

        alreadyReadMessage = true;
    }

    return messageType;
}


///////////////////////////////////////////////////////////////////////////////

NetListenerRef NetListener::create(const uint16 port) {
    return new NetListener(port);
}


NetListener::NetListener(uint16 port) {
    NetworkDevice* nd = NetworkDevice::instance();

    // Start the listener socket
    Log::common()->print("Creating a listener            ");
    sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);
    
    if (sock == SOCKET_ERROR) {
        Log::common()->printf("FAIL");
        Log::common()->println(socketErrorCode());
        return;
    }
    Log::common()->println("Ok");

    const int T = true;

    // Set reuse address so that a new server can start up soon after
    // an old one has closed.
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 
                   (const char*)&T, sizeof(T)) == SOCKET_ERROR) {
        
        Log::common()->println("WARNING: Setting socket reuseaddr failed.");
        Log::common()->println(socketErrorCode());
    } else {
        Log::common()->println("Set socket option reuseaddr.");
    }

    
    if (! nd->bind(sock, NetAddress(0, port))) {
        Log::common()->printf("Unable to bind!\n");
        nd->closesocket(sock);
        sock = (SOCKET)SOCKET_ERROR;
        return;
    }

    Log::common()->printf("Listening on port %5d        ", port);

    // listen is supposed to return 0 when there is no error.
    // The 2nd argument is the number of connections to allow pending
    // at any time.
    int L = listen(sock, 100);
    if (L == SOCKET_ERROR) {
        Log::common()->println("FAIL");
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
        sock = (SOCKET)SOCKET_ERROR;
        return;
    }
    Log::common()->println("Ok");
    Log::common()->printf("Now listening on socket %d.\n\n", sock);
}


NetListener::~NetListener() {
    NetworkDevice* nd = NetworkDevice::instance();
    nd->closesocket(sock);
}


ReliableConduitRef NetListener::waitForConnection() {
    NetworkDevice* nd = NetworkDevice::instance();
    // The address of the connecting host
    SOCKADDR_IN    remote_addr;
    int iAddrLen = sizeof(remote_addr);

    Log::common()->println("Blocking in NetListener::waitForConnection().");

    SOCKET sClient = accept(sock, (struct sockaddr*) &remote_addr, 
                            (socklen_t*)&iAddrLen);

    if (sClient == SOCKET_ERROR) {
        Log::common()->println("Error in NetListener::acceptConnection.");
        Log::common()->println(socketErrorCode());
        nd->closesocket(sock);
        return NULL;
    }

    Log::common()->printf("%s connected, transferred to socket %d.\n", 
                         inet_ntoa(remote_addr.sin_addr), sClient);

    #ifndef G3D_WIN32
        return new ReliableConduit(sClient, 
                     NetAddress(htonl(remote_addr.sin_addr.s_addr), 
                                ntohs(remote_addr.sin_port)));
    #else
        return new ReliableConduit(sClient, 
                    NetAddress(ntohl(remote_addr.sin_addr.S_un.S_addr), 
                               ntohs(remote_addr.sin_port)));
    #endif
}


bool NetListener::ok() const {
    return (sock != 0) && (sock != SOCKET_ERROR);
}


bool NetListener::clientWaiting() const {
    return readWaiting(sock);
}

////////////////////////////////////////////////////////////////////////////////////////////////

void NetworkDevice::describeSystem(
    TextOutput& t) {

    t.writeSymbols("Network", "{");
    t.writeNewline();
    t.pushIndent();
    
    for (int i = 0; i < m_adapterArray.size(); ++i) {
        m_adapterArray[i].describe(t);
    }


    t.popIndent();
    t.writeSymbols("}");
    t.writeNewline();
    t.writeNewline();
}


void NetworkDevice::describeSystem(
    std::string&        s) {

    TextOutput t;
    describeSystem(t);
    t.commitString(s);
}

} // namespace