Linux BSD sockets blocking issue Post: 302222186

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Top Forums Programming Linux BSD sockets blocking issue Post 302222186 by johnmb on Wednesday 6th of August 2008 07:19:41 AM

08-06-2008

Registered User

my code

The following is my code for both server and client sockets: -

Code:

    bzero(&sa,sizeof(struct sockaddr_in)); /* clear our address */ 

    if (master) {

        if (gethostname(myname,MAXHOSTNAME) < 0) std::cerr << "Error hostname: " << myname; /* who are we? */ 
        hp= gethostbyname(myname); /* get our address info */     

        if (hp != NULL)  { 
            sa.sin_family= hp->h_addrtype; /* this is our host address */ 
            sa.sin_port= htons(port); /* this is our port number */ 
        }

        if ((s= socket(AF_INET,SOCK_STREAM,0)) >= 0)  {          /* create socket */  

            int on = 1;
            setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); 

            if (bind(s, reinterpret_cast<struct sockaddr*>(&sa), sizeof sa) >= 0)  {    /* bind address to socket */ 

                listen(s, 3); /* max # of queued connects */ 
                established = true;
                master_socket_ref = s;

                int flags = fcntl(master_socket_ref, F_GETFL, 0);
                fcntl(master_socket_ref, F_SETFL, flags | O_NONBLOCK | O_NOCTTY | O_NDELAY | O_RDWR | O_ASYNC); 

            }
            else close(s);
        } 
    }
    else {

        if ((hp= gethostbyname(node_name(node_ref).c_str())) != NULL)  {
  
            bzero(&sa,sizeof(sa)); 
            bcopy(hp->h_addr, (char *)&sa.sin_addr, hp->h_length); /* set address */ 

            sa.sin_family= hp->h_addrtype; 
            sa.sin_port= htons(port); 

            if ((s= socket(hp->h_addrtype,SOCK_STREAM,0)) >= 0)  {   /* get socket */ 

                int on = 1;
                setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); 

                if (connect(s, reinterpret_cast<struct sockaddr*>(&sa), sizeof sa) >= 0)  {       /* Connect */
                    established = true;
                    socket_ref = s;

                    int flags = fcntl(socket_ref, F_GETFL, 0);
                    fcntl(socket_ref, F_SETFL, flags | O_NONBLOCK | O_NOCTTY | O_NDELAY | O_RDWR | O_ASYNC); 
                }
                else close(s);   
            }
        }
    }

If I have set up a server listening socket using the above code, I accept a client as follows :-

Code:

    getsockname(master_socket_ref, reinterpret_cast<struct sockaddr*>(&isa), reinterpret_cast<socklen_t*>(&i));           /* for accept() */ 

    int on = 1;
    socket_ref = accept(master_socket_ref, reinterpret_cast<struct sockaddr*>(&isa), reinterpret_cast<socklen_t*>(&i));
    setsockopt(socket_ref, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); 

    int flags = fcntl(socket_ref, F_GETFL, 0);
    fcntl(socket_ref, F_SETFL, flags | O_NONBLOCK | O_NOCTTY | O_NDELAY | O_RDWR | O_ASYNC);

Last edited by jim mcnamara; 08-06-2008 at 08:22 AM.. Reason: please use code tags

johnmb

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LEARN ABOUT FREEBSD

sockstat

SOCKSTAT(1)						    BSD General Commands Manual 					       SOCKSTAT(1)

NAME

     sockstat -- list open sockets

SYNOPSIS

     sockstat [-46cLlu] [-j jid] [-p ports] [-P protocols]

DESCRIPTION

     The sockstat command lists open Internet or UNIX domain sockets.

     The following options are available:

     -4 	 Show AF_INET (IPv4) sockets.

     -6 	 Show AF_INET6 (IPv6) sockets.

     -c 	 Show connected sockets.

     -j jid	 Show only sockets belonging to the specified jail ID.

     -L 	 Only show Internet sockets if the local or foreign addresses are not in the loopback network prefix 127.0.0.0/8, or do not con-
		 tain the IPv6 loopback address ::1.

     -l 	 Show listening sockets.

     -p ports	 Only show Internet sockets if either the local or foreign port number is on the specified list.  The ports argument is a comma-
		 separated list of port numbers and ranges specified as first and last port separated by a dash.

     -P protocols
		 Only show sockets of the specified protocols.	The protocols argument is a comma-separated list of protocol names, as they are
		 defined in protocols(5).

     -u 	 Show AF_LOCAL (UNIX) sockets.

     If neither -4, -6 or -u is specified, sockstat will list sockets in all three domains.

     If neither -c or -l is specified, sockstat will list both listening and connected sockets.

     The information listed for each socket is:

     USER	      The user who owns the socket.

     COMMAND	      The command which holds the socket.

     PID	      The process ID of the command which holds the socket.

     FD 	      The file descriptor number of the socket.

     PROTO	      The transport protocol associated with the socket for Internet sockets, or the type of socket (stream or datagram) for UNIX
		      sockets.

     LOCAL ADDRESS    For Internet sockets, this is the address the local end of the socket is bound to (see getsockname(2)).  For bound UNIX
		      sockets, it is the socket's filename.  For other UNIX sockets, it is a right arrow followed by the endpoint's filename, or
		      ``??'' if the endpoint could not be determined.

     FOREIGN ADDRESS  (Internet sockets only) The address the foreign end of the socket is bound to (see getpeername(2)).

     If a socket is associated with more than one file descriptor, it is shown multiple times.	If a socket is not associated with any file
     descriptor, the first four columns have no meaning.

SEE ALSO

     fstat(1), netstat(1), procstat(1), inet(4), inet6(4), protocols(5)

HISTORY

     The sockstat command appeared in FreeBSD 3.1.

AUTHORS

     The sockstat command and this manual page were written by Dag-Erling Smorgrav <des@FreeBSD.org>.

BSD
								   May 16, 2012 							       BSD