Creating a TCP Ping Echo on User-Defined Protocols

Environment: Internet, networking

TCP Ping is necessary when measuring server functionality from different IP networks (mirror sites). As you see, it uses a TCP transport protocl instead of ICMP. To ping the remote (or local) server, it should be able to provide "NOOP" command (NO OPeration) followed by CRLF.

Such user-defined protocols can be:

  • SMTP/25;
  • FTP/21;
  • POP3/110;
  • and so forth (NOOP implemented).

Options included in demo project are the following:

  • -cv: Connective ping (default)
  • -ct: Continuous ping
  • -n: Specify NOOP command
  • -crlf: Append CRLF to NOOP
  • -t<t>: Specify timeout

Hence, you can specify NOOP command yourself, of course, if it differs from the default.

The reasonable question: How do you ping the HTTP server? To ping the HTTP server, you should specify a NOOP-command (because it's not implelemented in HTTP/1.x) as the implemented method. This time, a connective ping is better than a continuous ping. Let's see the connective ping source:

unsigned int CPing::PingConnective(char* szHost,
                                   unsigned int iPort,
                                   unsigned int iPackets)
{
  struct hostent* host = NULL;
  struct sockaddr_in saddr;
  unsigned int s = 0;
  unsigned int dw1, dw2, dw3;
  char szBuffer[256];

  if (iPackets>MAX_SENDS) return (0);
  free (Res);
  Res = (pingstore*)malloc (sizeof(pingstore)*iPackets);
  memset (Res, 0, sizeof(pingstore)*iPackets);
  if (!iBytesToRecv) iBytesToRecv = strlen(szNoop);

  host = gethostbyname (szHost);
  if (host==NULL) return (0);
  saddr.sin_family = AF_INET;
  saddr.sin_port = htons(iPort);
  saddr.sin_addr = *((struct in_addr*)host->h_addr);

  for (int i=0;i< iPackets;i++)
  {
    s = socket(AF_INET, SOCK_STREAM, 0);
    if (!s) return ((iTotalRes)?1:0);
    setsockopt(s, SOL_SOCKET, SO_RCVTIMEO,
              (char*)&iTimeOut, sizeof(iTimeOut));
    setsockopt(s, SOL_SOCKET, SO_SNDTIMEO,
              (char*)&iTimeOut, sizeof(iTimeOut));
    if (connect (s,(struct sockaddr*)&saddr, sizeof(saddr))
        == -1) return ((iTotalRes)?1:0);

    iTotalRes++;
    sprintf (szBuffer, "%s\r\n", szNoop);

    dw1 = GetTickCount();
    int iSent = send (s, szBuffer, strlen(szBuffer), 0);
    dw2 = GetTickCount();
    int iRecv = recv (s, szBuffer, iBytesToRecv, 0);
    dw3 = GetTickCount();

    Res[i].iPort       = iPort;
    Res[i].iTimeSend   = dw2-dw1;
    Res[i].iTimeRecv   = dw3-dw2;
    Res[i].iTotalSent  = ((iSent==SOCKET_ERROR)?0:iSent);
    Res[i].iTotalRecvd = ((iRecv==SOCKET_ERROR)?0:iRecv);

    closesocket (s);
  }
  return (1);
}

You can use a simple Perl script for it:

#!/usr/local/bin/perl
# ################################
# Connective ping to http-server
# ################################

die("httpping.pl <host> <packets> [-p<port>]\n")
     unless (scalar(@ARGV)>=2);
$host    = $ARGV[0];
$port    = 80;    # default, but you can change it
$packets = $ARGV[1];
$noop    = "GET / HTTP/1.0";

for ($i=2; $i< scalar(@ARGV);$i++)
{
  if ($ARGV[$i] =~ /^(\x2D\x70)/)
  {
    $port = substr ($ARGV[$i],2,length($ARGV[$i])-2);
  }
}

open (PING, "|ping.exe $host $port $packets -n -cv -crlf") ||
              die ("Error: ping executable not found\n");
print PING "$noop\n";
close (PING);

Example of Usage

> ping localhost 8080 10 -n -crlf -cv    # connective ping
Enter valid NOOP command: GET / HTTP/1.0
...

In conclusion, note that you can also modify the timeout value to extend or lower the "live time" of requests. I hope this will be very helpful for system administrators to audit their systems on "request-response" ability.

Downloads

Download demo program - 24 Kb
Download source - 2 Kb


Comments

  • Error in the code

    Posted by Ulfen on 05/21/2004 10:25am

    There is a small error in the code:

    s = socket(AF_INET, SOCK_STREAM, 0); if (!s) ...

    s == 0 could be a valid socket, so the check should be:

    if (s == SOCKET_ERROR) ...

    Reply
  • How can i messure the signal of the current interfaces xxx b/s ?

    Posted by Legacy on 12/19/2003 12:00am

    Originally posted by: mathabu

    best regards

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • The explosion in mobile devices and applications has generated a great deal of interest in APIs. Today's businesses are under increased pressure to make it easy to build apps, supply tools to help developers work more quickly, and deploy operational analytics so they can track users, developers, application performance, and more. Apigee Edge provides comprehensive API delivery tools and both operational and business-level analytics in an integrated platform. It is available as on-premise software or through …

  • As mobile devices have pushed their way into the enterprise, they have brought cloud apps along with them. This app explosion means account passwords are multiplying, which exposes corporate data and leads to help desk calls from frustrated users. This paper will discover how IT can improve user productivity, gain visibility and control over SaaS and mobile apps, and stop password sprawl. Download this white paper to learn: How you can leverage your existing AD to manage app access. Key capabilities to …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds