Socket Error::Address Already In Use

Question

I am facing this problem of Binding to socket. 1st instance works properly i.e. socket() returns success and hence forth bind() and listen(), accept() and hence recv() - All fine till here. 2nd instance throw error while binding "Address already in use"

I went through all the post earlier on this and i dont see any specific solution provided on the same.

My code is as below :-

if((status = getaddrinfo(NULL,"8080",&hints,&servinfo))!=0){
        ALOGE("Socket:: getaddrinfo failed %s\n",strerror(errno));
        return NULL;
    }

    server_sockfd = socket(servinfo->ai_family, servinfo->ai_socktype, servinfo->ai_protocol);
    if(server_sockfd == -1) {
        ALOGE("Socket:: Scoket System Call failed %s\n",strerror(errno));
        return NULL;
    }

    if ((setsockopt(server_sockfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int))) < 0)
    {
        ALOGE("Socket:: setsockopt failed %s\n",strerror(errno));
        return NULL;
    }

    ret = bind(server_sockfd, servinfo->ai_addr,servinfo->ai_addrlen);
    if(ret!=0) {
        ALOGE("Socket:: Error Binding on socket %s\n",strerror(errno));
        return NULL;
    }

This code runs on android platform.

I have properly closed each session before opening a new session as below :-

ret = shutdown(client_sockfd,0);
if(ret != 0)
    ALOGE("Socket:: Shutdown Called%s\n",strerror(errno));

I tried with close as well but it did not work.

Surprisingly the error does not disappear even when we try to open the socket after long time (as per TIME_WAIT logic)

Could anyone please guide me to proper call or API or Logic(in code and not on command line apart from directly killing the process) to handle this situation ?

You are (incorrectly) closing an accepted client socket, but are you also closing the listening server socket? You cannot bind a new TCP socket to the same IP/port that a previous socket is still bound to. Why are you trying to bind multiple sockets to the same IP/port in the first place? — Remy Lebeau
Thanks for your comments. Yes i call close in both client and server socket. The logic behind the same is my server thread is part of an application which is launched and based on successful launch i create the server thread.This thread need not unnecessarily be active even after my application is closed.To handle this condition i have tried to close the socket when my pthread_exit is called. As far as client is concerned i assume its OK to call close when client is done with its work. Please correct me wrong if my logic seems incorrect. — user5729621
You are clearly not closing everything correctly. Something is still open. Please provide a Minimal, Complete, and Verifiable example showing how you a managing all of the sockets. — Remy Lebeau
Where is the code that is calling close() on server_sockfd? Where is the code that is calling close() on client_sockfd? Again, please provide an MCVE showing all relevant code related to your sockets. — Remy Lebeau
Thanks @RemyLebeau I think i got the problem. I was closing the server socket fd which i got from accept() but was not closing server actual socket() fd Now it seems to work. Thanks for your information. Will keep not of posting etiquette. — user5729621

Aaditya Gavandalkar Aaditya Gavandalkar · Accepted Answer · 2015-12-30T07:22:08

A socket is one half a channel of communication between two computers over a network on a particular port. (the other half is the corresponding socket on the other computer)

Error is very clear I suppose in this case. As mentioned Address already in use, so the the socket you are trying to connect in the second attempt is already used (port was already occupied) -> maybe due to first socket connection.

To investigate further check another SO question here and here

Socket Error::Address Already In Use

2 Answers