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      1 #!/usr/sbin/dtrace -s
      2 /*
      3  * tcpwdist.d - simple TCP write distribution by process.
      4  *              Written in DTrace (Solaris 10 3/05).
      5  *
      6  * This measures the size of writes from applications to the TCP level, which
      7  * may well be much larger than the MTU size (this is application writes not
      8  * packet writes). It can help identify which process is creating network
      9  * traffic, and the size of the writes by that application. It uses a simple
     10  * probe that produces meaningful output for most protocols.
     11  *
     12  * Tracking TCP activity by process is complex for a number of reasons,
     13  * the greatest is that inbound TCP traffic is asynchronous to the process.
     14  * The easiest TCP traffic to match is writes, which this script demonstrates.
     15  * However there are still issues - for an inbound telnet connection the
     16  * writes are associated with the command, for example "ls -l", not something
     17  * meaningful such as "in.telnetd".
     18  *
     19  * Scripts that match TCP traffic properly include tcpsnoop and tcptop.
     20  *
     21  * $Id: tcpwdist.d,v 1.1.1.1 2015/09/30 22:01:09 christos Exp $
     22  *
     23  * USAGE:       tcpwdist.d          # wait several seconds, then hit Ctrl-C
     24  *
     25  * FIELDS:
     26  *		PID	process ID
     27  *		CMD	command and argument list
     28  *		value	TCP write payload size in bytes
     29  *		count	number of writes
     30  *
     31  * SEE ALSO:	tcpsnoop, tcptop
     32  *
     33  * COPYRIGHT: Copyright (c) 2005, 2006 Brendan Gregg.
     34  *
     35  * CDDL HEADER START
     36  *
     37  *  The contents of this file are subject to the terms of the
     38  *  Common Development and Distribution License, Version 1.0 only
     39  *  (the "License").  You may not use this file except in compliance
     40  *  with the License.
     41  *
     42  *  You can obtain a copy of the license at Docs/cddl1.txt
     43  *  or http://www.opensolaris.org/os/licensing.
     44  *  See the License for the specific language governing permissions
     45  *  and limitations under the License.
     46  *
     47  * CDDL HEADER END
     48  *
     49  * 09-Jul-2004	Brendan Gregg	Created this.
     50  * 14-Jun-2005	   "      "	Rewrote this as tcpwdist.d.
     51  * 20-Apr-2006	   "      "	Last update.
     52  */
     53 
     54 #pragma D option quiet
     55 
     56 /*
     57  * Print header
     58  */
     59 dtrace:::BEGIN
     60 {
     61 	printf("Tracing... Hit Ctrl-C to end.\n");
     62 }
     63 
     64 /*
     65  * Process TCP Write
     66  */
     67 fbt:ip:tcp_output:entry
     68 {
     69 	/* fetch details */
     70 	this->size = msgdsize(args[1]);
     71 
     72 	/* store details */
     73 	@Size[pid, curpsinfo->pr_psargs] = quantize(this->size);
     74 }
     75 
     76 /*
     77  * Print final report
     78  */
     79 dtrace:::END
     80 {
     81 	printa(" PID: %-6d CMD: %S\n%@d\n", @Size);
     82 }
     83