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Java example source code file (net_util_md.c)

This example Java source code file (net_util_md.c) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

af_inet, af_inet6, close_sockets_and_return, fd_set, ipproto_ip, jnicall, jniexport, net_winbind, null, sockaddr_in6, socket_error, socketaddress_len, sol_socket, wsagetlasterror

The net_util_md.c Java example source code

/*
 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include <winsock2.h>
#include <ws2tcpip.h>

#include "net_util.h"
#include "jni.h"

#ifndef IPTOS_TOS_MASK
#define IPTOS_TOS_MASK 0x1e
#endif
#ifndef IPTOS_PREC_MASK
#define IPTOS_PREC_MASK 0xe0
#endif

/* true if SO_RCVTIMEO is supported */
jboolean isRcvTimeoutSupported = JNI_TRUE;

/*
 * Table of Windows Sockets errors, the specific exception we
 * throw for the error, and the error text.
 *
 * Note that this table excludes OS dependent errors.
 *
 * Latest list of Windows Sockets errors can be found at :-
 * http://msdn.microsoft.com/library/psdk/winsock/errors_3wc2.htm
 */
static struct {
    int errCode;
    const char *exc;
    const char *errString;
} const winsock_errors[] = {
    { WSAEACCES,                0,      "Permission denied" },
    { WSAEADDRINUSE,            "BindException",        "Address already in use" },
    { WSAEADDRNOTAVAIL,         "BindException",        "Cannot assign requested address" },
    { WSAEAFNOSUPPORT,          0,      "Address family not supported by protocol family" },
    { WSAEALREADY,              0,      "Operation already in progress" },
    { WSAECONNABORTED,          0,      "Software caused connection abort" },
    { WSAECONNREFUSED,          "ConnectException",     "Connection refused" },
    { WSAECONNRESET,            0,      "Connection reset by peer" },
    { WSAEDESTADDRREQ,          0,      "Destination address required" },
    { WSAEFAULT,                0,      "Bad address" },
    { WSAEHOSTDOWN,             0,      "Host is down" },
    { WSAEHOSTUNREACH,          "NoRouteToHostException",       "No route to host" },
    { WSAEINPROGRESS,           0,      "Operation now in progress" },
    { WSAEINTR,                 0,      "Interrupted function call" },
    { WSAEINVAL,                0,      "Invalid argument" },
    { WSAEISCONN,               0,      "Socket is already connected" },
    { WSAEMFILE,                0,      "Too many open files" },
    { WSAEMSGSIZE,              0,      "The message is larger than the maximum supported by the underlying transport" },
    { WSAENETDOWN,              0,      "Network is down" },
    { WSAENETRESET,             0,      "Network dropped connection on reset" },
    { WSAENETUNREACH,           0,      "Network is unreachable" },
    { WSAENOBUFS,               0,      "No buffer space available (maximum connections reached?)" },
    { WSAENOPROTOOPT,           0,      "Bad protocol option" },
    { WSAENOTCONN,              0,      "Socket is not connected" },
    { WSAENOTSOCK,              0,      "Socket operation on nonsocket" },
    { WSAEOPNOTSUPP,            0,      "Operation not supported" },
    { WSAEPFNOSUPPORT,          0,      "Protocol family not supported" },
    { WSAEPROCLIM,              0,      "Too many processes" },
    { WSAEPROTONOSUPPORT,       0,      "Protocol not supported" },
    { WSAEPROTOTYPE,            0,      "Protocol wrong type for socket" },
    { WSAESHUTDOWN,             0,      "Cannot send after socket shutdown" },
    { WSAESOCKTNOSUPPORT,       0,      "Socket type not supported" },
    { WSAETIMEDOUT,             "ConnectException",     "Connection timed out" },
    { WSATYPE_NOT_FOUND,        0,      "Class type not found" },
    { WSAEWOULDBLOCK,           0,      "Resource temporarily unavailable" },
    { WSAHOST_NOT_FOUND,        0,      "Host not found" },
    { WSA_NOT_ENOUGH_MEMORY,    0,      "Insufficient memory available" },
    { WSANOTINITIALISED,        0,      "Successful WSAStartup not yet performed" },
    { WSANO_DATA,               0,      "Valid name, no data record of requested type" },
    { WSANO_RECOVERY,           0,      "This is a nonrecoverable error" },
    { WSASYSNOTREADY,           0,      "Network subsystem is unavailable" },
    { WSATRY_AGAIN,             0,      "Nonauthoritative host not found" },
    { WSAVERNOTSUPPORTED,       0,      "Winsock.dll version out of range" },
    { WSAEDISCON,               0,      "Graceful shutdown in progress" },
    { WSA_OPERATION_ABORTED,    0,      "Overlapped operation aborted" },
};

/*
 * Initialize Windows Sockets API support
 */
BOOL WINAPI
DllMain(HINSTANCE hinst, DWORD reason, LPVOID reserved)
{
    WSADATA wsadata;

    switch (reason) {
        case DLL_PROCESS_ATTACH:
            if (WSAStartup(MAKEWORD(2,2), &wsadata) != 0) {
                return FALSE;
            }
            break;

        case DLL_PROCESS_DETACH:
            WSACleanup();
            break;

        default:
            break;
    }
    return TRUE;
}

void initLocalAddrTable () {}
void parseExclusiveBindProperty (JNIEnv *env) {}

/*
 * Since winsock doesn't have the equivalent of strerror(errno)
 * use table to lookup error text for the error.
 */
JNIEXPORT void JNICALL
NET_ThrowNew(JNIEnv *env, int errorNum, char *msg)
{
    int i;
    int table_size = sizeof(winsock_errors) /
                     sizeof(winsock_errors[0]);
    char exc[256];
    char fullMsg[256];
    char *excP = NULL;

    /*
     * If exception already throw then don't overwrite it.
     */
    if ((*env)->ExceptionOccurred(env)) {
        return;
    }

    /*
     * Default message text if not provided
     */
    if (!msg) {
        msg = "no further information";
    }

    /*
     * Check table for known winsock errors
     */
    i=0;
    while (i < table_size) {
        if (errorNum == winsock_errors[i].errCode) {
            break;
        }
        i++;
    }

    /*
     * If found get pick the specific exception and error
     * message corresponding to this error.
     */
    if (i < table_size) {
        excP = (char *)winsock_errors[i].exc;
        jio_snprintf(fullMsg, sizeof(fullMsg), "%s: %s",
                     (char *)winsock_errors[i].errString, msg);
    } else {
        jio_snprintf(fullMsg, sizeof(fullMsg),
                     "Unrecognized Windows Sockets error: %d: %s",
                     errorNum, msg);

    }

    /*
     * Throw SocketException if no specific exception for this
     * error.
     */
    if (excP == NULL) {
        excP = "SocketException";
    }
    sprintf(exc, "%s%s", JNU_JAVANETPKG, excP);
    JNU_ThrowByName(env, exc, fullMsg);
}

void
NET_ThrowCurrent(JNIEnv *env, char *msg)
{
    NET_ThrowNew(env, WSAGetLastError(), msg);
}

void
NET_ThrowSocketException(JNIEnv *env, char* msg)
{
    static jclass cls = NULL;
    if (cls == NULL) {
        cls = (*env)->FindClass(env, "java/net/SocketException");
        CHECK_NULL(cls);
        cls = (*env)->NewGlobalRef(env, cls);
        CHECK_NULL(cls);
    }
    (*env)->ThrowNew(env, cls, msg);
}

void
NET_ThrowByNameWithLastError(JNIEnv *env, const char *name,
                   const char *defaultDetail) {
    char errmsg[255];
    sprintf(errmsg, "errno: %d, error: %s\n", WSAGetLastError(), defaultDetail);
    JNU_ThrowByNameWithLastError(env, name, errmsg);
}

jfieldID
NET_GetFileDescriptorID(JNIEnv *env)
{
    jclass cls = (*env)->FindClass(env, "java/io/FileDescriptor");
    CHECK_NULL_RETURN(cls, NULL);
    return (*env)->GetFieldID(env, cls, "fd", "I");
}

jint  IPv6_supported()
{
    SOCKET s = socket(AF_INET6, SOCK_STREAM, 0) ;
    if (s == INVALID_SOCKET) {
        return JNI_FALSE;
    }
    closesocket(s);

    return JNI_TRUE;
}

/*
 * Return the default TOS value
 */
int NET_GetDefaultTOS() {
    static int default_tos = -1;
    OSVERSIONINFO ver;
    HKEY hKey;
    LONG ret;

    /*
     * If default ToS already determined then return it
     */
    if (default_tos >= 0) {
        return default_tos;
    }

    /*
     * Assume default is "normal service"
     */
    default_tos = 0;

    /*
     * Which OS is this?
     */
    ver.dwOSVersionInfoSize = sizeof(ver);
    GetVersionEx(&ver);

    /*
     * If 2000 or greater then no default ToS in registry
     */
    if (ver.dwPlatformId == VER_PLATFORM_WIN32_NT) {
        if (ver.dwMajorVersion >= 5) {
            return default_tos;
        }
    }

    /*
     * Query the registry to see if a Default ToS has been set.
     * Different registry entry for NT vs 95/98/ME.
     */
    if (ver.dwPlatformId == VER_PLATFORM_WIN32_NT) {
        ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
                           "SYSTEM\\CurrentControlSet\\Services\\Tcp\\Parameters",
                           0, KEY_READ, (PHKEY)&hKey);
    } else {
        ret = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
                           "SYSTEM\\CurrentControlSet\\Services\\VxD\\MSTCP\\Parameters",
                           0, KEY_READ, (PHKEY)&hKey);
    }
    if (ret == ERROR_SUCCESS) {
        DWORD dwLen;
        DWORD dwDefaultTOS;
        ULONG ulType;
        dwLen = sizeof(dwDefaultTOS);

        ret = RegQueryValueEx(hKey, "DefaultTOS",  NULL, &ulType,
                             (LPBYTE)&dwDefaultTOS, &dwLen);
        RegCloseKey(hKey);
        if (ret == ERROR_SUCCESS) {
            default_tos = (int)dwDefaultTOS;
        }
    }
    return default_tos;
}

/* call NET_MapSocketOptionV6 for the IPv6 fd only
 * and NET_MapSocketOption for the IPv4 fd
 */
JNIEXPORT int JNICALL
NET_MapSocketOptionV6(jint cmd, int *level, int *optname) {

    switch (cmd) {
        case java_net_SocketOptions_IP_MULTICAST_IF:
        case java_net_SocketOptions_IP_MULTICAST_IF2:
            *level = IPPROTO_IPV6;
            *optname = IPV6_MULTICAST_IF;
            return 0;

        case java_net_SocketOptions_IP_MULTICAST_LOOP:
            *level = IPPROTO_IPV6;
            *optname = IPV6_MULTICAST_LOOP;
            return 0;
    }
    return NET_MapSocketOption (cmd, level, optname);
}

/*
 * Map the Java level socket option to the platform specific
 * level and option name.
 */

JNIEXPORT int JNICALL
NET_MapSocketOption(jint cmd, int *level, int *optname) {

    typedef struct {
        jint cmd;
        int level;
        int optname;
    } sockopts;

    static sockopts opts[] = {
        { java_net_SocketOptions_TCP_NODELAY,   IPPROTO_TCP,    TCP_NODELAY },
        { java_net_SocketOptions_SO_OOBINLINE,  SOL_SOCKET,     SO_OOBINLINE },
        { java_net_SocketOptions_SO_LINGER,     SOL_SOCKET,     SO_LINGER },
        { java_net_SocketOptions_SO_SNDBUF,     SOL_SOCKET,     SO_SNDBUF },
        { java_net_SocketOptions_SO_RCVBUF,     SOL_SOCKET,     SO_RCVBUF },
        { java_net_SocketOptions_SO_KEEPALIVE,  SOL_SOCKET,     SO_KEEPALIVE },
        { java_net_SocketOptions_SO_REUSEADDR,  SOL_SOCKET,     SO_REUSEADDR },
        { java_net_SocketOptions_SO_BROADCAST,  SOL_SOCKET,     SO_BROADCAST },
        { java_net_SocketOptions_IP_MULTICAST_IF,   IPPROTO_IP, IP_MULTICAST_IF },
        { java_net_SocketOptions_IP_MULTICAST_LOOP, IPPROTO_IP, IP_MULTICAST_LOOP },
        { java_net_SocketOptions_IP_TOS,            IPPROTO_IP, IP_TOS },

    };


    int i;

    /*
     * Map the Java level option to the native level
     */
    for (i=0; i<(int)(sizeof(opts) / sizeof(opts[0])); i++) {
        if (cmd == opts[i].cmd) {
            *level = opts[i].level;
            *optname = opts[i].optname;
            return 0;
        }
    }

    /* not found */
    return -1;
}


/*
 * Wrapper for setsockopt dealing with Windows specific issues :-
 *
 * IP_TOS and IP_MULTICAST_LOOP can't be set on some Windows
 * editions.
 *
 * The value for the type-of-service (TOS) needs to be masked
 * to get consistent behaviour with other operating systems.
 */
JNIEXPORT int JNICALL
NET_SetSockOpt(int s, int level, int optname, const void *optval,
               int optlen)
{
    int rv;
    int parg;
    int plen = sizeof(parg);

    if (level == IPPROTO_IP && optname == IP_TOS) {
        int *tos = (int *)optval;
        *tos &= (IPTOS_TOS_MASK | IPTOS_PREC_MASK);
    }

    if (optname == SO_REUSEADDR) {
        /*
         * Do not set SO_REUSEADDE if SO_EXCLUSIVEADDUSE is already set
         */
        rv = NET_GetSockOpt(s, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char *)&parg, &plen);
        if (rv == 0 && parg == 1) {
            return rv;
        }
    }

    rv = setsockopt(s, level, optname, optval, optlen);

    if (rv == SOCKET_ERROR) {
        /*
         * IP_TOS & IP_MULTICAST_LOOP can't be set on some versions
         * of Windows.
         */
        if ((WSAGetLastError() == WSAENOPROTOOPT) &&
            (level == IPPROTO_IP) &&
            (optname == IP_TOS || optname == IP_MULTICAST_LOOP)) {
            rv = 0;
        }

        /*
         * IP_TOS can't be set on unbound UDP sockets.
         */
        if ((WSAGetLastError() == WSAEINVAL) &&
            (level == IPPROTO_IP) &&
            (optname == IP_TOS)) {
            rv = 0;
        }
    }

    return rv;
}

/*
 * Wrapper for setsockopt dealing with Windows specific issues :-
 *
 * IP_TOS is not supported on some versions of Windows so
 * instead return the default value for the OS.
 */
JNIEXPORT int JNICALL
NET_GetSockOpt(int s, int level, int optname, void *optval,
               int *optlen)
{
    int rv;

    rv = getsockopt(s, level, optname, optval, optlen);


    /*
     * IPPROTO_IP/IP_TOS is not supported on some Windows
     * editions so return the default type-of-service
     * value.
     */
    if (rv == SOCKET_ERROR) {

        if (WSAGetLastError() == WSAENOPROTOOPT &&
            level == IPPROTO_IP && optname == IP_TOS) {

            int *tos;
            tos = (int *)optval;
            *tos = NET_GetDefaultTOS();

            rv = 0;
        }
    }

    return rv;
}

/*
 * Sets SO_ECLUSIVEADDRUSE if SO_REUSEADDR is not already set.
 */
void setExclusiveBind(int fd) {
    int parg;
    int plen = sizeof(parg);
    int rv = 0;
    rv = NET_GetSockOpt(fd, SOL_SOCKET, SO_REUSEADDR, (char *)&parg, &plen);
    if (rv == 0 && parg == 0) {
        parg = 1;
        rv = NET_SetSockOpt(fd, SOL_SOCKET, SO_EXCLUSIVEADDRUSE, (char*)&parg, plen);
    }
}

/*
 * Wrapper for bind winsock call - transparent converts an
 * error related to binding to a port that has exclusive access
 * into an error indicating the port is in use (facilitates
 * better error reporting).
 *
 * Should be only called by the wrapper method NET_WinBind
 */
JNIEXPORT int JNICALL
NET_Bind(int s, struct sockaddr *him, int len)
{
    int rv;
    rv = bind(s, him, len);

    if (rv == SOCKET_ERROR) {
        /*
         * If bind fails with WSAEACCES it means that a privileged
         * process has done an exclusive bind (NT SP4/2000/XP only).
         */
        if (WSAGetLastError() == WSAEACCES) {
            WSASetLastError(WSAEADDRINUSE);
        }
    }

    return rv;
}

/*
 * Wrapper for NET_Bind call. Sets SO_EXCLUSIVEADDRUSE
 * if required, and then calls NET_BIND
 */
JNIEXPORT int JNICALL
NET_WinBind(int s, struct sockaddr *him, int len, jboolean exclBind)
{
    if (exclBind == JNI_TRUE)
        setExclusiveBind(s);
    return NET_Bind(s, him, len);
}

JNIEXPORT int JNICALL
NET_SocketClose(int fd) {
    struct linger l;
    int ret;
    int len = sizeof (l);
    if (getsockopt(fd, SOL_SOCKET, SO_LINGER, (char *)&l, &len) == 0) {
        if (l.l_onoff == 0) {
            WSASendDisconnect(fd, NULL);
        }
    }
    ret = closesocket (fd);
    return ret;
}

JNIEXPORT int JNICALL
NET_Timeout(int fd, long timeout) {
    int ret;
    fd_set tbl;
    struct timeval t;
    t.tv_sec = timeout / 1000;
    t.tv_usec = (timeout % 1000) * 1000;
    FD_ZERO(&tbl);
    FD_SET(fd, &tbl);
    ret = select (fd + 1, &tbl, 0, 0, &t);
    return ret;
}


/*
 * differs from NET_Timeout() as follows:
 *
 * If timeout = -1, it blocks forever.
 *
 * returns 1 or 2 depending if only one or both sockets
 * fire at same time.
 *
 * *fdret is (one of) the active fds. If both sockets
 * fire at same time, *fdret = fd always.
 */
JNIEXPORT int JNICALL
NET_Timeout2(int fd, int fd1, long timeout, int *fdret) {
    int ret;
    fd_set tbl;
    struct timeval t, *tP = &t;
    if (timeout == -1) {
        tP = 0;
    } else {
        t.tv_sec = timeout / 1000;
        t.tv_usec = (timeout % 1000) * 1000;
    }
    FD_ZERO(&tbl);
    FD_SET(fd, &tbl);
    FD_SET(fd1, &tbl);
    ret = select (0, &tbl, 0, 0, tP);
    switch (ret) {
    case 0:
        return 0; /* timeout */
    case 1:
        if (FD_ISSET (fd, &tbl)) {
            *fdret= fd;
        } else {
            *fdret= fd1;
        }
        return 1;
    case 2:
        *fdret= fd;
        return 2;
    }
    return -1;
}


void dumpAddr (char *str, void *addr) {
    struct SOCKADDR_IN6 *a = (struct SOCKADDR_IN6 *)addr;
    int family = a->sin6_family;
    printf ("%s\n", str);
    if (family == AF_INET) {
        struct sockaddr_in *him = (struct sockaddr_in *)addr;
        printf ("AF_INET: port %d: %x\n", ntohs(him->sin_port),
                                          ntohl(him->sin_addr.s_addr));
    } else {
        int i;
        struct in6_addr *in = &a->sin6_addr;
        printf ("AF_INET6 ");
        printf ("port %d ", ntohs (a->sin6_port));
        printf ("flow %d ", a->sin6_flowinfo);
        printf ("addr ");
        for (i=0; i<7; i++) {
            printf ("%04x:", ntohs(in->s6_words[i]));
        }
        printf ("%04x", ntohs(in->s6_words[7]));
        printf (" scope %d\n", a->sin6_scope_id);
    }
}

/* Macro, which cleans-up the iv6bind structure,
 * closes the two sockets (if open),
 * and returns SOCKET_ERROR. Used in NET_BindV6 only.
 */

#define CLOSE_SOCKETS_AND_RETURN {      \
    if (fd != -1) {                     \
        closesocket (fd);               \
        fd = -1;                        \
    }                                   \
    if (ofd != -1) {                    \
        closesocket (ofd);              \
        ofd = -1;                       \
    }                                   \
    if (close_fd != -1) {               \
        closesocket (close_fd);         \
        close_fd = -1;                  \
    }                                   \
    if (close_ofd != -1) {              \
        closesocket (close_ofd);        \
        close_ofd = -1;                 \
    }                                   \
    b->ipv4_fd = b->ipv6_fd = -1;       \
    return SOCKET_ERROR;                \
}

/*
 * if ipv6 is available, call NET_BindV6 to bind to the required address/port.
 * Because the same port number may need to be reserved in both v4 and v6 space,
 * this may require socket(s) to be re-opened. Therefore, all of this information
 * is passed in and returned through the ipv6bind structure.
 *
 * If the request is to bind to a specific address, then this (by definition) means
 * only bind in either v4 or v6, and this is just the same as normal. ie. a single
 * call to bind() will suffice. The other socket is closed in this case.
 *
 * The more complicated case is when the requested address is ::0 or 0.0.0.0.
 *
 * Two further cases:
 * 2. If the reqeusted port is 0 (ie. any port) then we try to bind in v4 space
 *    first with a wild-card port argument. We then try to bind in v6 space
 *    using the returned port number. If this fails, we repeat the process
 *    until a free port common to both spaces becomes available.
 *
 * 3. If the requested port is a specific port, then we just try to get that
 *    port in both spaces, and if it is not free in both, then the bind fails.
 *
 * On failure, sockets are closed and an error returned with CLOSE_SOCKETS_AND_RETURN
 */

JNIEXPORT int JNICALL
NET_BindV6(struct ipv6bind* b, jboolean exclBind) {
    int fd=-1, ofd=-1, rv, len;
    /* need to defer close until new sockets created */
    int close_fd=-1, close_ofd=-1;
    SOCKETADDRESS oaddr; /* other address to bind */
    int family = b->addr->him.sa_family;
    int ofamily;
    u_short port; /* requested port parameter */
    u_short bound_port;

    if (family == AF_INET && (b->addr->him4.sin_addr.s_addr != INADDR_ANY)) {
        /* bind to v4 only */
        int ret;
        ret = NET_WinBind ((int)b->ipv4_fd, (struct sockaddr *)b->addr,
                                sizeof (struct sockaddr_in), exclBind);
        if (ret == SOCKET_ERROR) {
            CLOSE_SOCKETS_AND_RETURN;
        }
        closesocket (b->ipv6_fd);
        b->ipv6_fd = -1;
        return 0;
    }
    if (family == AF_INET6 && (!IN6_IS_ADDR_ANY(&b->addr->him6.sin6_addr))) {
        /* bind to v6 only */
        int ret;
        ret = NET_WinBind ((int)b->ipv6_fd, (struct sockaddr *)b->addr,
                                sizeof (struct SOCKADDR_IN6), exclBind);
        if (ret == SOCKET_ERROR) {
            CLOSE_SOCKETS_AND_RETURN;
        }
        closesocket (b->ipv4_fd);
        b->ipv4_fd = -1;
        return 0;
    }

    /* We need to bind on both stacks, with the same port number */

    memset (&oaddr, 0, sizeof(oaddr));
    if (family == AF_INET) {
        ofamily = AF_INET6;
        fd = (int)b->ipv4_fd;
        ofd = (int)b->ipv6_fd;
        port = (u_short)GET_PORT (b->addr);
        IN6ADDR_SETANY (&oaddr.him6);
        oaddr.him6.sin6_port = port;
    } else {
        ofamily = AF_INET;
        ofd = (int)b->ipv4_fd;
        fd = (int)b->ipv6_fd;
        port = (u_short)GET_PORT (b->addr);
        oaddr.him4.sin_family = AF_INET;
        oaddr.him4.sin_port = port;
        oaddr.him4.sin_addr.s_addr = INADDR_ANY;
    }

    rv = NET_WinBind(fd, (struct sockaddr *)b->addr, SOCKETADDRESS_LEN(b->addr), exclBind);
    if (rv == SOCKET_ERROR) {
        CLOSE_SOCKETS_AND_RETURN;
    }

    /* get the port and set it in the other address */
    len = SOCKETADDRESS_LEN(b->addr);
    if (getsockname(fd, (struct sockaddr *)b->addr, &len) == -1) {
        CLOSE_SOCKETS_AND_RETURN;
    }
    bound_port = GET_PORT (b->addr);
    SET_PORT (&oaddr, bound_port);
    if ((rv=NET_WinBind (ofd, (struct sockaddr *) &oaddr,
                         SOCKETADDRESS_LEN (&oaddr), exclBind)) == SOCKET_ERROR) {
        int retries;
        int sotype, arglen=sizeof(sotype);

        /* no retries unless, the request was for any free port */

        if (port != 0) {
            CLOSE_SOCKETS_AND_RETURN;
        }

        getsockopt(fd, SOL_SOCKET, SO_TYPE, (void *)&sotype, &arglen);

#define SOCK_RETRIES 50
        /* 50 is an arbitrary limit, just to ensure that this
         * cannot be an endless loop. Would expect socket creation to
         * succeed sooner.
         */
        for (retries = 0; retries < SOCK_RETRIES; retries ++) {
            int len;
            close_fd = fd; fd = -1;
            close_ofd = ofd; ofd = -1;
            b->ipv4_fd = SOCKET_ERROR;
            b->ipv6_fd = SOCKET_ERROR;

            /* create two new sockets */
            fd = (int)socket (family, sotype, 0);
            if (fd == SOCKET_ERROR) {
                CLOSE_SOCKETS_AND_RETURN;
            }
            ofd = (int)socket (ofamily, sotype, 0);
            if (ofd == SOCKET_ERROR) {
                CLOSE_SOCKETS_AND_RETURN;
            }

            /* bind random port on first socket */
            SET_PORT (&oaddr, 0);
            rv = NET_WinBind (ofd, (struct sockaddr *)&oaddr, SOCKETADDRESS_LEN(&oaddr),
                              exclBind);
            if (rv == SOCKET_ERROR) {
                CLOSE_SOCKETS_AND_RETURN;
            }
            /* close the original pair of sockets before continuing */
            closesocket (close_fd);
            closesocket (close_ofd);
            close_fd = close_ofd = -1;

            /* bind new port on second socket */
            len = SOCKETADDRESS_LEN(&oaddr);
            if (getsockname(ofd, (struct sockaddr *)&oaddr, &len) == -1) {
                CLOSE_SOCKETS_AND_RETURN;
            }
            bound_port = GET_PORT (&oaddr);
            SET_PORT (b->addr, bound_port);
            rv = NET_WinBind (fd, (struct sockaddr *)b->addr, SOCKETADDRESS_LEN(b->addr),
                              exclBind);

            if (rv != SOCKET_ERROR) {
                if (family == AF_INET) {
                    b->ipv4_fd = fd;
                    b->ipv6_fd = ofd;
                } else {
                    b->ipv4_fd = ofd;
                    b->ipv6_fd = fd;
                }
                return 0;
            }
        }
        CLOSE_SOCKETS_AND_RETURN;
    }
    return 0;
}

/*
 * Determine the default interface for an IPv6 address.
 *
 * Returns :-
 *      0 if error
 *      > 0 interface index to use
 */
jint getDefaultIPv6Interface(JNIEnv *env, struct SOCKADDR_IN6 *target_addr)
{
    int ret;
    DWORD b;
    struct sockaddr_in6 route;
    SOCKET fd = socket(AF_INET6, SOCK_STREAM, 0);
    if (fd == INVALID_SOCKET) {
        return 0;
    }

    ret = WSAIoctl(fd, SIO_ROUTING_INTERFACE_QUERY,
                    (void *)target_addr, sizeof(struct sockaddr_in6),
                    (void *)&route, sizeof(struct sockaddr_in6),
                    &b, 0, 0);
    if (ret == SOCKET_ERROR) {
        // error
        closesocket(fd);
        return 0;
    } else {
        closesocket(fd);
        return route.sin6_scope_id;
    }
}

/* If address types is IPv6, then IPv6 must be available. Otherwise
 * no address can be generated. In the case of an IPv4 Inetaddress this
 * method will return an IPv4 mapped address where IPv6 is available and
 * v4MappedAddress is TRUE. Otherwise it will return a sockaddr_in
 * structure for an IPv4 InetAddress.
*/
JNIEXPORT int JNICALL
NET_InetAddressToSockaddr(JNIEnv *env, jobject iaObj, int port, struct sockaddr *him,
                          int *len, jboolean v4MappedAddress) {
    jint family, iafam;
    iafam = getInetAddress_family(env, iaObj);
    family = (iafam == IPv4)? AF_INET : AF_INET6;
    if (ipv6_available() && !(family == AF_INET && v4MappedAddress == JNI_FALSE)) {
        struct SOCKADDR_IN6 *him6 = (struct SOCKADDR_IN6 *)him;
        jbyte caddr[16];
        jint address, scopeid = 0;
        jint cached_scope_id = 0;

        if (family == AF_INET) { /* will convert to IPv4-mapped address */
            memset((char *) caddr, 0, 16);
            address = getInetAddress_addr(env, iaObj);
            if (address == INADDR_ANY) {
                /* we would always prefer IPv6 wildcard address
                caddr[10] = 0xff;
                caddr[11] = 0xff; */
            } else {
                caddr[10] = 0xff;
                caddr[11] = 0xff;
                caddr[12] = ((address >> 24) & 0xff);
                caddr[13] = ((address >> 16) & 0xff);
                caddr[14] = ((address >> 8) & 0xff);
                caddr[15] = (address & 0xff);
            }
        } else {
            getInet6Address_ipaddress(env, iaObj, (char *)caddr);
            scopeid = getInet6Address_scopeid(env, iaObj);
            cached_scope_id = (jint)(*env)->GetIntField(env, iaObj, ia6_cachedscopeidID);
        }

        memset((char *)him6, 0, sizeof(struct SOCKADDR_IN6));
        him6->sin6_port = (u_short) htons((u_short)port);
        memcpy((void *)&(him6->sin6_addr), caddr, sizeof(struct in6_addr) );
        him6->sin6_family = AF_INET6;
        if ((family == AF_INET6) && IN6_IS_ADDR_LINKLOCAL( &(him6->sin6_addr) )
            && (!scopeid && !cached_scope_id)) {
            cached_scope_id = getDefaultIPv6Interface(env, him6);
            (*env)->SetIntField(env, iaObj, ia6_cachedscopeidID, cached_scope_id);
        }
        him6->sin6_scope_id = scopeid != 0 ? scopeid : cached_scope_id;
        *len = sizeof(struct SOCKADDR_IN6) ;
    } else {
        struct sockaddr_in *him4 = (struct sockaddr_in*)him;
        jint address;
        if (family != AF_INET) {
          JNU_ThrowByName(env, JNU_JAVANETPKG "SocketException", "Protocol family unavailable");
          return -1;
        }
        memset((char *) him4, 0, sizeof(struct sockaddr_in));
        address = getInetAddress_addr(env, iaObj);
        him4->sin_port = htons((short) port);
        him4->sin_addr.s_addr = (u_long) htonl(address);
        him4->sin_family = AF_INET;
        *len = sizeof(struct sockaddr_in);
    }
    return 0;
}

JNIEXPORT jint JNICALL
NET_GetPortFromSockaddr(struct sockaddr *him) {
    if (him->sa_family == AF_INET6) {
        return ntohs(((struct sockaddr_in6*)him)->sin6_port);
    } else {
        return ntohs(((struct sockaddr_in*)him)->sin_port);
    }
}

int
NET_IsIPv4Mapped(jbyte* caddr) {
    int i;
    for (i = 0; i < 10; i++) {
        if (caddr[i] != 0x00) {
            return 0; /* false */
        }
    }

    if (((caddr[10] & 0xff) == 0xff) && ((caddr[11] & 0xff) == 0xff)) {
        return 1; /* true */
    }
    return 0; /* false */
}

int
NET_IPv4MappedToIPv4(jbyte* caddr) {
    return ((caddr[12] & 0xff) << 24) | ((caddr[13] & 0xff) << 16) | ((caddr[14] & 0xff) << 8)
        | (caddr[15] & 0xff);
}

int
NET_IsEqual(jbyte* caddr1, jbyte* caddr2) {
    int i;
    for (i = 0; i < 16; i++) {
        if (caddr1[i] != caddr2[i]) {
            return 0; /* false */
        }
    }
    return 1;
}

int getScopeID (struct sockaddr *him) {
    struct SOCKADDR_IN6 *him6 = (struct SOCKADDR_IN6 *)him;
    return him6->sin6_scope_id;
}

int cmpScopeID (unsigned int scope, struct sockaddr *him) {
    struct SOCKADDR_IN6 *him6 = (struct SOCKADDR_IN6 *)him;
    return him6->sin6_scope_id == scope;
}

/**
 * Wrapper for select/poll with timeout on a single file descriptor.
 *
 * flags (defined in net_util_md.h can be any combination of
 * NET_WAIT_READ, NET_WAIT_WRITE & NET_WAIT_CONNECT.
 *
 * The function will return when either the socket is ready for one
 * of the specified operation or the timeout expired.
 *
 * It returns the time left from the timeout, or -1 if it expired.
 */

jint
NET_Wait(JNIEnv *env, jint fd, jint flags, jint timeout)
{
    jlong prevTime = JVM_CurrentTimeMillis(env, 0);
    jint read_rv;

    while (1) {
        jlong newTime;
        fd_set rd, wr, ex;
        struct timeval t;

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

        FD_ZERO(&rd);
        FD_ZERO(&wr);
        FD_ZERO(&ex);
        if (flags & NET_WAIT_READ) {
          FD_SET(fd, &rd);
        }
        if (flags & NET_WAIT_WRITE) {
          FD_SET(fd, &wr);
        }
        if (flags & NET_WAIT_CONNECT) {
          FD_SET(fd, &wr);
          FD_SET(fd, &ex);
        }

        errno = 0;
        read_rv = select(fd+1, &rd, &wr, &ex, &t);

        newTime = JVM_CurrentTimeMillis(env, 0);
        timeout -= (jint)(newTime - prevTime);
        if (timeout <= 0) {
          return read_rv > 0 ? 0 : -1;
        }
        newTime = prevTime;

        if (read_rv > 0) {
          break;
        }


      } /* while */

    return timeout;
}

int NET_Socket (int domain, int type, int protocol) {
    SOCKET sock;
    sock = socket (domain, type, protocol);
    if (sock != INVALID_SOCKET) {
        SetHandleInformation((HANDLE)(uintptr_t)sock, HANDLE_FLAG_INHERIT, FALSE);
    }
    return (int)sock;
}

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