CODEWITHSUNDEEP
clinuxsocketsgcc
bholanath
bholanath

Reputation: 1753

Unable to create Socket after creating 1020 times to communicate

I am following the socket programming tutorial from this link Socket programming. and trying to develop an application where client will receive Network Time from Server and print the time . Here is how the program works-

Server is waiting for incoming connection and while client try to connect with server , server accept the connection and server sends the time to client. After receiving through socket client print the time.

After every message send to client , server close the connection and wait for next. Client is able to communicate with server for 1020 times. If I try to communicate more than 1020 time from client to server then I got Error- Unable to Create Socket

I am trying to develop the application where client can communicate with server infinite times or atleast 20000 times.

I am suspecting , may be memory is not freed while creating socket in client side.

Sample output :

counter=1017 Sun Jul  6 03:19:48 2014
counter=1018 Sun Jul  6 03:19:48 2014
counter=1019 Sun Jul  6 03:19:48 2014
counter=1020 Sun Jul  6 03:19:48 2014

Error : Could not create socket (WHY ??)

Here is my code

Server.c

#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <time.h> 

int main(int argc, char *argv[])
{
    int listenfd = 0, connfd = 0;
    struct sockaddr_in serv_addr; 

    char sendBuff[1025];
    time_t ticks; 

    listenfd = socket(AF_INET, SOCK_STREAM, 0);
    memset(&serv_addr, '0', sizeof(serv_addr));
    memset(sendBuff, '0', sizeof(sendBuff)); 

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(5000); 

    bind(listenfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr)); 

    listen(listenfd, 10); 

    while(1)
    {
        connfd = accept(listenfd, (struct sockaddr*)NULL, NULL); 

        ticks = time(NULL);
        snprintf(sendBuff, sizeof(sendBuff), "%.24s\r\n", ctime(&ticks));
        write(connfd, sendBuff, strlen(sendBuff)); 

        close(connfd);
      //  sleep(1);
     }
}

Client.c

#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <arpa/inet.h> 

int main(int argc, char *argv[])
{
    int sockfd = 0, n = 0;
    char recvBuff[1024];
    struct sockaddr_in serv_addr; 

    if(argc != 2)
    {
        printf("\n Usage: %s <ip of server> \n",argv[0]);
        return 1;
    } 

int counter=0;

while(counter <2000)
{
    memset(recvBuff, '0',sizeof(recvBuff));
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        printf("\n Error : Could not create socket \n");
        return 1;
    } 

    memset(&serv_addr, '0', sizeof(serv_addr)); 

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(5000); 

    if(inet_pton(AF_INET, argv[1], &serv_addr.sin_addr)<=0)
    {
        printf("\n inet_pton error occured\n");
        return 1;
    } 

    if( connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
    {
       printf("\n Error : Connect Failed \n");
       return 1;
    } 

    while ( (n = read(sockfd, recvBuff, sizeof(recvBuff)-1)) > 0)
    {
        recvBuff[n] = 0;
        printf("counter=%d ",counter);
        fputs(recvBuff, stdout);
       /*
        if(fputs(recvBuff, stdout) == EOF)
        {
            printf("\n Error : Fputs error\n");
        }
        */ 
    } 
    
counter++;
}
    if(n < 0)
    {
        printf("\n Read error \n");
    } 

    return 0;
}

I am using gcc under Ubuntu. Any help to understand the reason and resolve and run the program for around 20000 will be highly appreciated. Thanks in advance.

Upvotes: 2

Views: 2154

Answers (4)

Mystic Lin
Mystic Lin

Reputation: 375

I have the same problem. In my situation, after fopen("/proc/net/route" , "r");, I forgot to fclose().

After fopen("/proc/net/route" , "r");, I found the socket number increased, so I think this is the same problem.

Upvotes: 0

Srikanth
Srikanth

Reputation: 445

Since you are using the same client for connecting to the server , you dont need to start all over again the socket & connect process , You Can block the client till you get some data from server. Otherwise , you are unnecessary wasting lot of kernel resources and you are closing and opening at a very rapid phase too , which is not a good idea !

Upvotes: 0

user3553031
user3553031

Reputation: 6214

You appear to be leaking a socket in your client code. You're creating sockets inside your outer loop, but you never close them. Try adding close(sockfd); to the end of your outer loop, and to all points where you break or return out of it.

Upvotes: 2

Jamie Cockburn
Jamie Cockburn

Reputation: 7555

You are not closing your client's socket after using it. You need this line in your client code:

close(sockfd);

After your while loop.

Upvotes: 4

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