Echo-service-using-TCP-sockets-.rar_Keepalive_Linger_SO_KEEPALIV

/* echoClient.c - TCP echo client program */ /* Copyright 1984-1997 Wind River Systems, Inc. */ /* modification history -------------------- 01f,06nov97,mm added copyright. 01e,29Sep97,mm cast arg 1 of `bzero' , cast arg 2 of `connect', cast arg 4 of `setsockopt' 01d,17Sep97,mm deleted line IMPORT int tcp_keepidle = 1 01c,17Sep97,mm changed int optionVal to char optionVal 01b,16Sep97,mm included <stdio.h> <string.h> <arpa/inet.h> 01a,07Feb94,ms cleaned up for VxDemo. */ #include <stdio.h> #include <string.h> #include <stddef.h> #include <arpa/inet.h> #include <vxWorks.h> #include "socket.h" #include "in.h" #include "ioLib.h" #include "errno.h" #include "netinet/tcp.h" #include <sockLib.h> LOCAL int defaultTimes = 50; /* default number of times for echo service */ LOCAL int defaultPort = 7001; /* default port number used by echoTcpServer */ LOCAL char defaultServer[16] = "147.11.184.2"; /* default echo server's inet * address */ LOCAL char defaultMessage[80] = "Hello World!!!\n"; /* Buffer for the default * message */ /* Change the default keepidle time (timeout for probing the idle * connection) from several hours to few minutes. */ /*IMPORT int tcp_keepidle = 1;*/ LOCAL int echoTcpClientSock (char *, int); /* set up TCP socket */ LOCAL void echoTcpClient (int, int, char*); /*UDP echo client*/ /***************************************************************************** * echoTcpClientRun - Runs the TCP client task for echo service * * DESCRIPTION * * The TCP echo client repeatedly sends the input and then reads it back * using TCP socket communication. * * ECHO services are important tools that network managers use to test * reachability (to make sure the connection works), debug protocol * software, and identify routing problems. * * This also demonstrates the usage of SO_REUSEADDR, SO_KEEPALIVE and * TCP_NODELAY set socket options. * * CONFIGURATION: * * You need to set/change the value of the defaultPort (should be greater than * 5000 - unreserved port) and the defaultServer (internet address of the * echo server) variables. * * EXAMPLE: * * Run this echoTcpClientRun task on one VxWorks system as follows * after starting the echoTcpServerRun task from another VxWorks system. * The other half of the demonstration is in echoServer.c. * * sp (echoTcpClientRun, inetAddrOfServer, port, numTimes, msg) * * where inetAddrOfServer is the internet address of the network * interface of the VxWorks system running echoTcpServerRun task, * port is the port number used by the echoTcpServer (should be * greater than 5000), numTimes is the number of times echo service is * requested, and msg is the message to echo. * * example: * -> sp (echoTcpClientRun, "147.11.184.2", 7001, 5, "Hello World!!!") * */ void echoTcpClientRun ( char *server, /* internet address of the echo server; * 0 to use default */ int port, /* port number; 0 to use the last used one*/ int numTimes, /* number of times for echo service */ char *msg /* Message to echo; 0 to use default or last used message */ ) { int clientSock; /* socket fd opened to the server */ clientSock = echoTcpClientSock (server, port); if (clientSock == ERROR) printf ("Error creating client socket\n"); else echoTcpClient (clientSock, numTimes, msg); close (clientSock); } /***************************************************************************** * echoTcpClientSock - Sets up a TCP socket connection with echo client * * DESCRIPTION * * Sets up a TCP socket connection with echo server with various socket * options. * * RETURNS: OK or ERROR */ int echoTcpClientSock ( char *server, /* inet number of echo server */ int port /* port number */ ) { int echoClientSock; /* socket opened to echo server */ int optionVal; /* value of setsocket option */ struct sockaddr_in serverAddr; /* server's address */ if (server == NULL) server = defaultServer; if (port == 0) port = defaultPort; else defaultPort = port; if (port < 5000) { printf ("echoTcpClientSock: invalid port number\n"); return (ERROR); } /* open the socket */ echoClientSock = socket (AF_INET, SOCK_STREAM, 0); if (echoClientSock == ERROR) { perror ("echoTcpClientSock: socket open failed"); return (ERROR); } optionVal = 1; /* Turn ON the different setsockopt options */ /* Specify the SO_REUSEADDR option to bind a stream socket to a local * port that may be still bound to another stream socket that may be * hanging around with a "zombie" protocol control block whose context * is not yet freed from previous sessions. */ if (setsockopt (echoClientSock, SOL_SOCKET, SO_REUSEADDR, (char *)&optionVal, sizeof(optionVal)) == ERROR) { perror ("echoTcpClientSock: setsockopt SO_REUSEADDR failed"); close (echoClientSock); return (ERROR); } /* Specify the TCP_NODELAY option for protocols such as X Window System * Protocol that require immediate delivery of many small messages. * * By default VxWorks uses congestion avoidance algorithm * for virtual terminal protocols and bulk data transfer * protocols. When the TCP_NODELAY option is turned on and there are * segments to be sent out, TCP bypasses the congestion * avoidance algorithm and sends the segments out when there * is enough space in the send window. */ if (setsockopt (echoClientSock, IPPROTO_TCP, TCP_NODELAY, (char *)&optionVal, sizeof(optionVal)) == ERROR) { perror ("echoTcpClientSock: setsockopt TCP_NODELAY failed"); close (echoClientSock); return (ERROR); } /* Specify the SO_KEEPALIVE option, and the transport protocol (TCP) * initiates a timer to detect a dead connection which prevents an * an application from hanging on an invalid connection. */ if (setsockopt (echoClientSock, SOL_SOCKET, SO_KEEPALIVE, (char *)&optionVal, sizeof(optionVal)) == ERROR) { perror ("echoTcpClientSock: setsockopt SO_KEEPALIVE failed"); close (echoClientSock); return (ERROR); } /* Set up server's internet address and connect to the server */ /* Zero out the sock_addr structures. * This MUST be done before the socket calls. */ bzero ((char *) &serverAddr, sizeof (serverAddr)); serverAddr.sin_family = AF_INET; serverAddr.sin_port = htons (port); serverAddr.sin_addr.s_addr = inet_addr (server); printf ("Server's address is %x:\n", ntohl (serverAddr.sin_addr.s_addr)); if (connect (echoClientSock, (struct sockaddr *) &serverAddr, sizeof (serverAddr)) < 0) { perror ("echoTcpClientSock: connect failed"); close (echoClientSock); return (ERROR); } printf ("Connected...\n"); return (echoClientSock); } /***************************************************************************** * echoTcpClient - the TCP client for echo service * * DESCRIPTION * * echoTcpClient enters a loop that repeatedly sends message across the * TCP connection to the echo server, reads it back and prints it. * After all input messages have been sent to the server, received back, * and printed successfully, the client exits. * */ void echoTcpClient ( int echoClientSock, /* client socket fd */ int times, /* number of times for echo service */ char *message /* message buffer for echo service */ ) { int ix; /* loop counter */ int msgLen; /* length of the