Resolved: Socket binding through JNI

#include <jni.h>        // JNI header provided by JDK<br />
#include <stdio.h><br />
#include <string.h><br />
#include <sys/types.h><br />
#include <sys/socket.h><br />
#include <netinet/in.h><br />
#include <errno.h><br />
#include <fcntl.h><br />
#include "Socket.h"   // Generated</p>
<p>JNIEXPORT jint JNICALL Java_Socket_socket(JNIEnv *env, jobject thisObj) {<br />
    int sockfd;</p>
<p>    if ((sockfd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {<br />
        printf("socket creation failed...\n");<br />
        return (jint)-1;<br />
    } else {<br />
        printf("Socket successfully created..\n");<br />
        printf("Socket descriptor: %d\n", sockfd);<br />
        return (jint) sockfd;<br />
    }<br />
}</p>
<p>JNIEXPORT jint JNICALL Java_Socket_bind(JNIEnv *env, jobject thisObj, jint sockfd, jint port) {<br />
    struct sockaddr_in servaddr;<br />
    bzero(&servaddr, sizeof(servaddr));</p>
<p>    int c_sockfd = (int) sockfd;<br />
    short int c_port = (int) port;</p>
<p>    printf("socket binding sockfd - %d, port - %d\n", c_sockfd, c_port);</p>
<p>    // assign IP, PORT<br />
    servaddr.sin_family = AF_INET;<br />
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);<br />
    servaddr.sin_port = htons(c_port);<br />
    printf("htons - %d\n", htons(c_port));</p>
<p>    int one = 1;<br />
    int res = setsockopt(c_sockfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));<br />
    res = setsockopt(c_sockfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));<br />
    if (res < 0) {
        perror("setsockopt");
    }

    printf("sizeof - %d\n", sizeof(servaddr));

    if (fcntl(c_sockfd, F_GETFD) != -1 || errno != EBADF) {
        printf("fd is valid\n");
    } else {
        printf("fd is invalid\n");
    }

    // Binding newly created socket to given IP and verification
    if ((bind(sockfd, (struct sockaddr*)&servaddr, sizeof(servaddr))) != 0) {
        printf("socket bind failed...\n");
        printf("Error code: %d\n", errno);
        return (jint)-1;
    }
    else {
        printf("Socket successfully binded..\n");
        return (jint)0;
    }
}
[/code]

</p>



Java code<br> 


<p>[code]public class Socket {<br />
    static {<br />
        System.load(".../libsocket.so");<br />
    }</p>
<p>    private native int socket();</p>
<p>    private native int bind(int sockFd, int port);</p>
<p>    public static void main(String[] args) {<br />
        var socket = new Socket();<br />
        int sockFd = socket.socket();<br />
        System.out.println("sockFd " + sockFd);<br />
        int bind = socket.bind(sockFd, 9900);<br />
        System.out.println("Bind " + bind);<br />
    }<br />
}

Socket descriptor: 4
socket binding sockfd - 4, port - 9900
htons - 44070
sizeof - 16
fd is valid
socket bind failed...
Error code: 22

if ((sockfd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {

if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {