/*
 * Copyright (c) 2001, 2018, 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 "jni.h"
#include "jni_util.h"
#include "jvm.h"
#include "jlong.h"

#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>

#if defined(__linux__) || defined(_ALLBSD_SOURCE)
#include <netinet/in.h>
#endif

#include "net_util.h"
#include "net_util_md.h"
#include "nio.h"
#include "nio_util.h"

#include "sun_nio_ch_DatagramChannelImpl.h"

static jfieldID dci_senderID;   /* sender in sun.nio.ch.DatagramChannelImpl */
static jfieldID dci_senderAddrID; /* sender InetAddress in sun.nio.ch.DatagramChannelImpl */
static jfieldID dci_senderPortID; /* sender port in sun.nio.ch.DatagramChannelImpl */
static jclass isa_class;        /* java.net.InetSocketAddress */
static jmethodID isa_ctorID;    /*   .InetSocketAddress(InetAddress, int) */

JNIEXPORT void JNICALL
Java_sun_nio_ch_DatagramChannelImpl_initIDs(JNIEnv *env, jclass clazz)
{
    clazz = (*env)->FindClass(env, "java/net/InetSocketAddress");
    CHECK_NULL(clazz);
    isa_class = (*env)->NewGlobalRef(env, clazz);
    if (isa_class == NULL) {
        JNU_ThrowOutOfMemoryError(env, NULL);
        return;
    }
    isa_ctorID = (*env)->GetMethodID(env, clazz, "<init>",
                                     "(Ljava/net/InetAddress;I)V");
    CHECK_NULL(isa_ctorID);

    clazz = (*env)->FindClass(env, "sun/nio/ch/DatagramChannelImpl");
    CHECK_NULL(clazz);
    dci_senderID = (*env)->GetFieldID(env, clazz, "sender",
                                      "Ljava/net/SocketAddress;");
    CHECK_NULL(dci_senderID);
    dci_senderAddrID = (*env)->GetFieldID(env, clazz,
                                          "cachedSenderInetAddress",
                                          "Ljava/net/InetAddress;");
    CHECK_NULL(dci_senderAddrID);
    dci_senderPortID = (*env)->GetFieldID(env, clazz,
                                          "cachedSenderPort", "I");
    CHECK_NULL(dci_senderPortID);
}

JNIEXPORT void JNICALL
Java_sun_nio_ch_DatagramChannelImpl_disconnect0(JNIEnv *env, jobject this,
                                                jobject fdo, jboolean isIPv6)
{
    jint fd = fdval(env, fdo);
    int rv;

#if defined(__solaris__)
    rv = connect(fd, 0, 0);
#elif defined(__APPLE__)
    // On macOS systems we use disconnectx
    rv = disconnectx(fd, SAE_ASSOCID_ANY, SAE_CONNID_ANY);
#else
    SOCKETADDRESS sa;
    memset(&sa, 0, sizeof(sa));
#if defined(_ALLBSD_SOURCE)
    sa.sa.sa_family = isIPv6 ? AF_INET6 : AF_INET;
#else
    sa.sa.sa_family = AF_UNSPEC;
#endif
    socklen_t len = isIPv6 ? sizeof(struct sockaddr_in6) :
                             sizeof(struct sockaddr_in);

    rv = connect(fd, &sa.sa, len);
#endif

#if defined(_ALLBSD_SOURCE) && !defined(__APPLE__)
    // On _ALLBSD_SOURCE except __APPLE__ we consider EADDRNOTAVAIL
    // error to be OK and ignore it. __APPLE__ systems are excluded
    // in this check since for __APPLE__ systems, unlike other BSD systems,
    // we issue a "disconnectx" call (a few lines above),
    // which isn't expected to return this error code.
    if (rv < 0 && errno == EADDRNOTAVAIL)
        rv = errno = 0;
#elif defined(_AIX)
    /* See W. Richard Stevens, "UNIX Network Programming, Volume 1", p. 254:
     * 'Setting the address family to AF_UNSPEC might return EAFNOSUPPORT
     * but that is acceptable.
     */
    if (rv < 0 && errno == EAFNOSUPPORT)
        rv = errno = 0;
#endif // defined(_ALLBSD_SOURCE) || defined(_AIX)

    if (rv < 0)
        handleSocketError(env, errno);
}

JNIEXPORT jint JNICALL
Java_sun_nio_ch_DatagramChannelImpl_receive0(JNIEnv *env, jobject this,
                                             jobject fdo, jlong address,
                                             jint len, jboolean connected)
{
    jint fd = fdval(env, fdo);
    void *buf = (void *)jlong_to_ptr(address);
    SOCKETADDRESS sa;
    socklen_t sa_len = sizeof(SOCKETADDRESS);
    jboolean retry = JNI_FALSE;
    jint n = 0;
    jobject senderAddr;

    if (len > MAX_PACKET_LEN) {
        len = MAX_PACKET_LEN;
    }

    do {
        retry = JNI_FALSE;
        n = recvfrom(fd, buf, len, 0, &sa.sa, &sa_len);
        if (n < 0) {
            if (errno == EAGAIN || errno == EWOULDBLOCK) {
                return IOS_UNAVAILABLE;
            }
            if (errno == EINTR) {
                return IOS_INTERRUPTED;
            }
            if (errno == ECONNREFUSED) {
                if (connected == JNI_FALSE) {
                    retry = JNI_TRUE;
                } else {
                    JNU_ThrowByName(env, JNU_JAVANETPKG
                                    "PortUnreachableException", 0);
                    return IOS_THROWN;
                }
            } else {
                return handleSocketError(env, errno);
            }
        }
    } while (retry == JNI_TRUE);

    /*
     * If the source address and port match the cached address
     * and port in DatagramChannelImpl then we don't need to
     * create InetAddress and InetSocketAddress objects.
     */
    senderAddr = (*env)->GetObjectField(env, this, dci_senderAddrID);
    if (senderAddr != NULL) {
        if (!NET_SockaddrEqualsInetAddress(env, &sa, senderAddr)) {
            senderAddr = NULL;
        } else {
            jint port = (*env)->GetIntField(env, this, dci_senderPortID);
            if (port != NET_GetPortFromSockaddr(&sa)) {
                senderAddr = NULL;
            }
        }
    }
    if (senderAddr == NULL) {
        jobject isa = NULL;
        int port = 0;
        jobject ia = NET_SockaddrToInetAddress(env, &sa, &port);
        if (ia != NULL) {
            isa = (*env)->NewObject(env, isa_class, isa_ctorID, ia, port);
        }
        CHECK_NULL_RETURN(isa, IOS_THROWN);

        (*env)->SetObjectField(env, this, dci_senderAddrID, ia);
        (*env)->SetIntField(env, this, dci_senderPortID,
                            NET_GetPortFromSockaddr(&sa));
        (*env)->SetObjectField(env, this, dci_senderID, isa);
    }
    return n;
}

JNIEXPORT jint JNICALL
Java_sun_nio_ch_DatagramChannelImpl_send0(JNIEnv *env, jobject this,
                                          jboolean preferIPv6, jobject fdo, jlong address,
                                          jint len, jobject destAddress, jint destPort)
{
    jint fd = fdval(env, fdo);
    void *buf = (void *)jlong_to_ptr(address);
    SOCKETADDRESS sa;
    int sa_len = 0;
    jint n = 0;

    if (len > MAX_PACKET_LEN) {
        len = MAX_PACKET_LEN;
    }

    if (NET_InetAddressToSockaddr(env, destAddress, destPort, &sa,
                                  &sa_len, preferIPv6) != 0) {
      return IOS_THROWN;
    }

    n = sendto(fd, buf, len, 0, &sa.sa, sa_len);
    if (n < 0) {
        if (errno == EAGAIN || errno == EWOULDBLOCK) {
            return IOS_UNAVAILABLE;
        }
        if (errno == EINTR) {
            return IOS_INTERRUPTED;
        }
        if (errno == ECONNREFUSED) {
            JNU_ThrowByName(env, JNU_JAVANETPKG "PortUnreachableException", 0);
            return IOS_THROWN;
        }
        return handleSocketError(env, errno);
    }
    return n;
}
