From 2e2516781661f5a4b41e4dc79d423250e057f271 Mon Sep 17 00:00:00 2001
From: "David J. Wilder" <wilder@wilder.ibm.com>
Date: Thu, 8 Oct 2009 11:00:20 -0700
Subject: This script (tcp_trace) can be used to trace tcp connection
 parameters and state changes.  This work was original inspired by Stephen
 Hemminger's TCP cwnd snooper (net/ipv4/tcp_probe.c). Tcp_trace is a helpful
 tool for troubleshooting connection performance issues.

---
 testsuite/systemtap.examples/index.html            |   3 +
 testsuite/systemtap.examples/index.txt             |   8 +
 testsuite/systemtap.examples/keyword-index.html    |   6 +
 testsuite/systemtap.examples/keyword-index.txt     |  16 +
 .../systemtap.examples/network/tcp_trace.meta      |  14 +
 testsuite/systemtap.examples/network/tcp_trace.stp | 744 +++++++++++++++++++++
 testsuite/systemtap.examples/network/tcp_trace.txt |  26 +
 7 files changed, 817 insertions(+)
 create mode 100644 testsuite/systemtap.examples/network/tcp_trace.meta
 create mode 100755 testsuite/systemtap.examples/network/tcp_trace.stp
 create mode 100644 testsuite/systemtap.examples/network/tcp_trace.txt

(limited to 'testsuite/systemtap.examples')

diff --git a/testsuite/systemtap.examples/index.html b/testsuite/systemtap.examples/index.html
index 66118bfc..b0d70509 100644
--- a/testsuite/systemtap.examples/index.html
+++ b/testsuite/systemtap.examples/index.html
@@ -139,6 +139,9 @@ keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-inde
 <li><a href="network/tcp_connections.stp">network/tcp_connections.stp</a> - Track Creation of Incoming TCP Connections<br>
 keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TCP">TCP</a> <a href="keyword-index.html#SOCKET">SOCKET</a> <br>
 <p>The tcp_connections.stp script prints information for each new incoming TCP connection accepted by the computer. The information includes the UID, the command accepting the connection, the PID of the command, the port the connection is on, and the IP address of the originator of the request.</p></li>
+<li><a href="network/tcp_trace.stp">network/tcp_trace.stp</a> - Tcp connection tracing utility.<br>
+keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TRACE">TRACE</a> <br>
+<p>This scripts traces a given tcp connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port.</p></li>
 <li><a href="network/tcpdumplike.stp">network/tcpdumplike.stp</a> - Dump of Received TCP Packets<br>
 keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TRAFFIC">TRAFFIC</a> <br>
 <p>The tcpdumplike.stp prints out a line for each TCP packet received. Each line includes the source and destination IP addresses, the source and destination ports, and flags.</p></li>
diff --git a/testsuite/systemtap.examples/index.txt b/testsuite/systemtap.examples/index.txt
index cb2b10d3..29ca3c7d 100644
--- a/testsuite/systemtap.examples/index.txt
+++ b/testsuite/systemtap.examples/index.txt
@@ -317,6 +317,14 @@ keywords: network tcp socket
   originator of the request.
 
 
+network/tcp_trace.stp - Tcp connection tracing utility.
+keywords: network trace
+
+  This scripts traces a given tcp connection based on the filter
+  parameters given by the user. The indexing is done by the 4 tuples
+  local address, remote address, local port, remote port.
+
+
 network/tcpdumplike.stp - Dump of Received TCP Packets
 keywords: network traffic
 
diff --git a/testsuite/systemtap.examples/keyword-index.html b/testsuite/systemtap.examples/keyword-index.html
index 2aad9adf..f66269a2 100644
--- a/testsuite/systemtap.examples/keyword-index.html
+++ b/testsuite/systemtap.examples/keyword-index.html
@@ -249,6 +249,9 @@ keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-inde
 <li><a href="network/tcp_connections.stp">network/tcp_connections.stp</a> - Track Creation of Incoming TCP Connections<br>
 keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TCP">TCP</a> <a href="keyword-index.html#SOCKET">SOCKET</a> <br>
 <p>The tcp_connections.stp script prints information for each new incoming TCP connection accepted by the computer. The information includes the UID, the command accepting the connection, the PID of the command, the port the connection is on, and the IP address of the originator of the request.</p></li>
+<li><a href="network/tcp_trace.stp">network/tcp_trace.stp</a> - Tcp connection tracing utility.<br>
+keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TRACE">TRACE</a> <br>
+<p>This scripts traces a given tcp connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port.</p></li>
 <li><a href="network/tcpdumplike.stp">network/tcpdumplike.stp</a> - Dump of Received TCP Packets<br>
 keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TRAFFIC">TRAFFIC</a> <br>
 <p>The tcpdumplike.stp prints out a line for each TCP packet received. Each line includes the source and destination IP addresses, the source and destination ports, and flags.</p></li>
@@ -435,6 +438,9 @@ keywords: <a href="keyword-index.html#PROCESS">PROCESS</a> <a href="keyword-inde
 <li><a href="general/para-callgraph.stp">general/para-callgraph.stp</a> - Callgraph tracing with arguments<br>
 keywords: <a href="keyword-index.html#TRACE">TRACE</a> <a href="keyword-index.html#CALLGRAPH">CALLGRAPH</a> <br>
 <p>Print a timed per-thread callgraph, complete with function parameters and return values.  The first parameter names the function probe points to trace.  The optional second parameter names the probe points for trigger functions, which acts to enable tracing for only those functions that occur while the current thread is nested within the trigger.</p></li>
+<li><a href="network/tcp_trace.stp">network/tcp_trace.stp</a> - Tcp connection tracing utility.<br>
+keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-index.html#TRACE">TRACE</a> <br>
+<p>This scripts traces a given tcp connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port.</p></li>
 </ul>
 <h3><a name="TRACEPOINT">TRACEPOINT</a></h3>
 <ul>
diff --git a/testsuite/systemtap.examples/keyword-index.txt b/testsuite/systemtap.examples/keyword-index.txt
index 01661cf1..a3765f95 100644
--- a/testsuite/systemtap.examples/keyword-index.txt
+++ b/testsuite/systemtap.examples/keyword-index.txt
@@ -503,6 +503,14 @@ keywords: network tcp socket
   originator of the request.
 
 
+network/tcp_trace.stp - Tcp connection tracing utility.
+keywords: network trace
+
+  This scripts traces a given tcp connection based on the filter
+  parameters given by the user. The indexing is done by the 4 tuples
+  local address, remote address, local port, remote port.
+
+
 network/tcpdumplike.stp - Dump of Received TCP Packets
 keywords: network traffic
 
@@ -974,6 +982,14 @@ keywords: trace callgraph
   the trigger.
 
 
+network/tcp_trace.stp - Tcp connection tracing utility.
+keywords: network trace
+
+  This scripts traces a given tcp connection based on the filter
+  parameters given by the user. The indexing is done by the 4 tuples
+  local address, remote address, local port, remote port.
+
+
 = TRACEPOINT =
 
 network/dropwatch.stp - Watch Where Socket Buffers are Freed in the Kernel
diff --git a/testsuite/systemtap.examples/network/tcp_trace.meta b/testsuite/systemtap.examples/network/tcp_trace.meta
new file mode 100644
index 00000000..2783c89b
--- /dev/null
+++ b/testsuite/systemtap.examples/network/tcp_trace.meta
@@ -0,0 +1,14 @@
+title: Tcp connection tracing utility.
+name: tcp_trace.stp
+version: 1.0
+author: varuncha@in.ibm.com wilder@us.ibm.com
+keywords: network trace
+subsystem: network
+status: production
+exit: user-controlled
+output: timed
+scope: per-socket
+arg_[0-9]+: tcp_trace.stp  filter=all|state|txq|rxq|srtt|snd_cwnd|snd_wnd|rexmit|pmtu|ssthresh|timer|rcvwnd [timeout=<sec>] [update=change|all] Rule
+description: This scripts traces a given tcp connection based on the filter parameters given by the user. The indexing is done by the 4 tuples local address, remote address, local port, remote port.
+test_check: stap -p4 tcp_trace.stp
+test_installcheck: stap tcp_trace.stp 127.0.0.1:*-127.0.0.1:* timeout=1
diff --git a/testsuite/systemtap.examples/network/tcp_trace.stp b/testsuite/systemtap.examples/network/tcp_trace.stp
new file mode 100755
index 00000000..4763b386
--- /dev/null
+++ b/testsuite/systemtap.examples/network/tcp_trace.stp
@@ -0,0 +1,744 @@
+#! /usr/bin/env stap
+/*
+ *	Copyright (C) 2009 IBM Corp.
+ *	This file is part of systemtap, and is free software.  You can
+ *	redistribute it and/or modify it under the terms of the GNU General
+ *	Public License (GPL); either version 2, or (at your option) any
+ *	later version.
+ *
+ *	Version 0.1     wilder@us.ibm.com	2009-05-13
+ *	Version 0.3     varuncha@in.ibm.com	2009-05-20
+ *	Version 1.0	wilder@us.ibm.com	2009-09-24
+ *	Version 1.1	wilder@us.ibm.com	2009-10-08
+ *
+ *	Tcp connection tracing utility.
+ *
+ *	Description:
+ *	This script traces tcp connections and displays connection parameters.
+ *	The filter option specifies what parameters are to be displayed. Address
+ *	"rules" must be supplied to limit what connections are to be traced.
+ *
+ *	Synopsis:
+ *	tcp_trace.stp	[filter=all|state|txq|rxq|srtt|snd_cwnd|snd_wnd|rexmit\
+ *			|pmtu|ssthresh|timer|rcvwnd|length]\
+ *			[timeout=<N sec>]\
+ *			[update=change|all]\
+ *
+ *	Rule format:
+ *	  <local ip-address>:<local-port>-<remote ip-address>:<remote-port>
+ *
+ *	filter  tcp_trace collects the socket state and other connection
+ *		parameters from various probe points in the tcp stack; however,
+ *		not all this data may needed when debugging a tcp problem.
+ *		Specifying only the required parameters reduces analysis time.
+ *		Multiple parameters can be specified by using
+ *		','.
+ *
+ *	timeout (optional) When a timeout value (in seconds) is specified
+ *		tcp_trace will automatically terminate it's run at the end of
+ *		the specified time.  By default the script will run until the
+ *		user terminates it by typing a ^c.
+ *
+ *	update  (optional) By default the script only displays data if there
+ *		is a value change in a parameters specified in the "filter".
+ *		This can be changed by specifying "update=all", which will
+ *		output parameters of every packet that hits the probe.
+ *		Note: Changes to the packet length will not trigger an update.
+ *
+ *	Rules	Rules limit what connections will be traced. Multiple rules may
+ *		be given separated by a space. A wild-card value can be used
+ *		for any component of the filter. Rules can be used to limit
+ *		tracing to a single socket or allow many sockets to be traced.
+ *		Memory consumed by the tracer will increase with the number
+ *		of connections being traced.
+ *
+ *		The Rule Format is:
+ *		<local-address>:<local-port>-<remote address>:<remote-port>
+ *
+ *		-Address are specified as ipv4 dot notation address.
+ *		-Ports are specified as decimal numbers.
+ *
+ *		"*" character can be used in any field to indicate a wild-card
+ *		value.
+ *
+ *		Note: The number of active sockets that can be traced is
+ *		limited by MAXMAPENTRIES.
+ *
+ *	Examples:
+ *		Here are some examples of using tcp_trace:
+ *
+ *		Trace TCP connection from 172.16.15.160 to 172.16.15.1 on
+ *		port 22 with state,txq,rxq,pmtu filter.
+ *
+ *		tcp_trace.stp filter=state,txq,rxq,pmtu timeout=100\
+ *					172.16.15.160:*-172.16.15.1:22
+ *
+ *		Trace TCP connection from any address to the local http server.
+ *		all parameters are displayed for every packet.
+ *
+ *		tcp_trace.stp filter=all update=all *.*.*.*:*-*.*.*.*:80
+ */
+
+global tcp_state;
+global timer_info;
+
+global filter;
+global key_list;
+global lastkey;
+global number_of_rules;
+
+global timeout = -1;
+global always_update;
+
+global snd_cwnd_flg;
+global snd_cwnd;
+
+global snd_wnd_flg;
+global snd_wnd;
+
+global srtt_flg;
+global srtt;
+
+global state_flg;
+global state;
+
+global txq_flg;
+global txq;
+
+global rxq_flg;
+global rxq;
+
+global rexmit_flg;
+global rexmit;
+
+global pmtu_flg;
+global pmtu;
+
+global ssthresh_flg;
+global ssthresh;
+
+global timer_flg;
+global tx_timer;
+global find_timer;
+
+global rcvwnd_flg;
+global rcvwnd;
+
+global length_flg;
+global length;
+
+probe begin
+{
+	number_of_rules = process_cmdline()
+
+	if ( number_of_rules < 1)
+		usage("One or more connection rules must be specified!")
+	if ( number_of_rules < 0 )
+		usage("Incorrect connection rule format!")
+
+	init_tcp_state()
+	init_timer_info()
+
+	printf("Start TCP Probing.....\n\n");
+	print_header();
+}
+
+function init_tcp_state ()
+{
+	tcp_state[1] = "ESTABLISHED"
+	tcp_state[2] = "SYN_SENT"
+	tcp_state[3] = "SYN_RECV"
+	tcp_state[4] = "FIN_WAIT1"
+	tcp_state[5] = "FIN_WAIT2"
+	tcp_state[6] = "TIME_WAIT"
+	tcp_state[7] = "CLOSE"
+	tcp_state[8] = "CLOSE_WAIT"
+	tcp_state[9] = "LAST_ACK"
+	tcp_state[10] = "LISTEN"
+	tcp_state[11] = "CLOSING"
+}
+
+function state_num2str:string ( state:long )
+{
+	return (state in tcp_state ? tcp_state[state] : "UNDEF")
+}
+
+function init_timer_info ()
+{
+	timer_info[0] = ""
+	timer_info[1] = "Rxmit"
+	timer_info[2] = "Delack"
+	timer_info[3] = "Probe"
+	timer_info[4] = "Keepalv"
+}
+
+function timer_info_num2str:string ( timer:long )
+{
+	return (timer in timer_info ? timer_info[timer] : "UNDEF")
+}
+
+probe	kernel.function("tcp_rcv_established"),
+	kernel.function("tcp_rcv_state_process")
+{
+	sk = $sk
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	if ( is_packet_updated(key,sk) ) {
+		length[key] = $skb->len;
+		print_packet_info(key, 0)
+	}
+}
+
+probe kernel.function("tcp_transmit_skb")
+{
+	sk = $sk
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	if ( is_packet_updated(key,sk) ) {
+		length[key] = $skb->len;
+		print_packet_info(key, 1)
+	}
+}
+
+probe kernel.function("tcp_keepalive_timer")
+{
+	if ( !timer_flg ) next;
+
+	sk = $data;
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	is_packet_updated(key,sk)
+	length[key] = 0
+	tx_timer[key] = 4;
+	print_packet_info(key, 1)
+	tx_timer[key] = 0;
+}
+
+probe kernel.function("tcp_delack_timer")
+{
+	if ( !timer_flg ) next;
+
+	sk = $data;
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	is_packet_updated(key,sk)
+	length[key] = 0
+	tx_timer[key] = 2;
+	print_packet_info(key, 1)
+	tx_timer[key] = 0;
+}
+
+probe kernel.function("tcp_send_probe0")
+{
+	if ( !timer_flg ) next;
+
+	sk = $sk
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	if ( find_timer[key] == 3 ) {
+		find_timer[key] = 0
+		tx_timer[key] = 3;
+		is_packet_updated(key,sk)
+		length[key] = 0
+		print_packet_info(key, 1)
+		tx_timer[key] = 0;
+	}
+}
+
+probe kernel.function("tcp_retransmit_skb")
+{
+	if ( !timer_flg ) next;
+
+	sk = $sk;
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	if ( find_timer[key] == 1 ) {
+		find_timer[key] = 0
+		tx_timer[key] = 1;
+		is_packet_updated(key,sk)
+		length[key] = $skb->len
+		print_packet_info(key,1)
+		tx_timer[key] = 0;
+	}
+}
+
+probe kernel.function("tcp_write_timer")
+{
+	if ( !timer_flg ) next;
+
+	sk = $data
+	key = filter_key(sk)
+	if ( !key ) next;
+
+	/* Don't trace calls to tcp_retransmit_skb()
+	 * or tcp_send_probe0 that were not the result of a
+	 * write timer expiration.
+	 */
+	find_timer[key] = @cast(sk, "inet_connection_sock")->icsk_pending
+}
+
+probe kernel.function("tcp_set_state")
+{
+	sk = $sk
+	new_state = $state
+	TCP_CLOSE = 7
+	TCP_CLOSE_WAIT = 8
+	key = filter_key(sk)
+	if ( key && ((new_state == TCP_CLOSE)||(new_state == TCP_CLOSE_WAIT))){
+		if (state_flg && state[key]) print_close(key,new_state);
+		clean_up(key);
+	}
+}
+
+function print_header()
+{
+	printf("%-22s","Source Address")
+	printf("%-22s","Dest Address")
+	if (state_flg) printf("%-12s","State")
+	if (timer_flg) printf("%-8s","Timer")
+	if (txq_flg) printf("%8s","Tx-Q")
+	if (rxq_flg) printf("%8s","Rx-Q")
+	if (pmtu_flg) printf("%8s","PMTU")
+	if (snd_cwnd_flg) printf("%8s","SndCwnd")
+	if (snd_wnd_flg) printf("%8s","SndWnd")
+	if (rcvwnd_flg) printf("%8s","RcvWnd")
+	if (srtt_flg) printf("%8s","SSRT")
+	if (ssthresh_flg) printf("%14s","Ssthreshold")
+	if (rexmit_flg) printf("%8s","Rexmit")
+	if (length_flg) printf("%8s","Length")
+	printf("\n");
+}
+
+function print_packet_info:long ( key:long, SourceIsLocal:long)
+{
+	foreach ( [laddr, raddr, lport, rport] in key_list ){
+			if ( key_list[laddr, raddr, lport, rport] == key )
+				break
+	}
+
+	local_addr = sprintf("%s:%d",ip_ntop(htonl(laddr)), lport)
+	remote_addr = sprintf("%s:%d",ip_ntop(htonl(raddr)) ,rport)
+
+	SourceIsLocal ? printf("%-22s%-22s",local_addr,remote_addr):
+			printf("%-22s%-22s",remote_addr,local_addr)
+
+	if (state_flg) printf("%-12s",state_num2str(state[key]))
+	if (timer_flg) printf("%-8s",timer_info_num2str(tx_timer[key]))
+	if (txq_flg) printf("%8d",txq[key])
+	if (rxq_flg) printf("%8d",rxq[key])
+	if (pmtu_flg) printf("%8d",pmtu[key])
+	if (snd_cwnd_flg) printf("%8d",snd_cwnd[key])
+	if (snd_wnd_flg) printf("%8d",snd_wnd[key])
+	if (rcvwnd_flg) printf("%8d",rcvwnd[key])
+	if (srtt_flg) printf("%8d",srtt[key])
+	if (ssthresh_flg) printf("%14d",ssthresh[key])
+	if (rexmit_flg) printf("%8d",rexmit[key])
+	if (length_flg && length[key]) printf("%8d", length[key])
+	printf("\n");
+}
+
+function print_close:long (key:long, new_state:long)
+{
+	foreach ( [laddr, raddr, lport, rport] in key_list ){
+			if ( key_list[laddr, raddr, lport, rport] == key )
+				break
+	}
+
+	local_addr = sprintf("%s:%d",ip_ntop(htonl(laddr)), lport)
+	remote_addr = sprintf("%s:%d",ip_ntop(htonl(raddr)) ,rport)
+
+	printf("%-22s%-22s",local_addr,remote_addr)
+	printf("%-12s",state_num2str(new_state))
+	printf("\n");
+}
+
+/*
+ * Update the values in the data collection arrays, returns 1 if one or more
+ * values have changed.
+ */
+function is_packet_updated:long ( key:long, sk:long )
+{
+	packet_updated = 0
+
+	if ( !key ) return 0
+
+	if ( state_flg ) {
+		new_state = @cast(sk, "sock_common")->skc_state
+		if( always_update || (state[key] != new_state) ){
+			state[key]= new_state
+			packet_updated = 1
+		}
+	}
+
+	if ( txq_flg ) {
+		if(@cast(sk, "sock_common")->skc_state == 10)
+			new_txq = @cast(sk, "sock")->sk_max_ack_backlog
+                else
+			new_txq = @cast(sk, "tcp_sock")->write_seq -
+					@cast(sk, "tcp_sock")->snd_una
+		if( always_update || (txq[key] != new_txq) ){
+			txq[key] = new_txq
+			packet_updated = 1
+		}
+	}
+
+	if ( rxq_flg ) {
+		if(@cast(sk, "sock_common")->skc_state == 10)
+			new_rxq = @cast(sk, "sock")->sk_ack_backlog
+		else
+			new_rxq = @cast(sk, "tcp_sock")->rcv_nxt -
+					@cast(sk, "tcp_sock")->copied_seq
+
+		if( always_update || (rxq[key] != new_rxq) ){
+			rxq[key] = new_rxq
+			packet_updated = 1
+		}
+	}
+
+	if( rexmit_flg ) {
+		new_rexmit = @cast(sk, "inet_connection_sock")->icsk_retransmits
+		if( always_update || (rexmit[key] != new_rexmit ) ){
+			rexmit[key] = new_rexmit
+			packet_updated = 1
+		}
+	}
+
+	if ( pmtu_flg ) {
+		new_pmtu = @cast(sk, "inet_connection_sock")->icsk_pmtu_cookie
+		if( always_update || (pmtu[key] != new_pmtu) ){
+			pmtu[key] = new_pmtu
+			packet_updated = 1
+		}
+	}
+
+	if ( snd_cwnd_flg ) {
+		new_snd_cwnd = @cast(sk, "tcp_sock")->snd_cwnd
+		if( always_update || (snd_cwnd[key] != new_snd_cwnd) ){
+			snd_cwnd[key] = new_snd_cwnd
+			packet_updated = 1
+		}
+	}
+
+
+	if ( snd_wnd_flg ) {
+		new_snd_wnd = @cast(sk, "tcp_sock")->snd_wnd
+		if( always_update || (snd_wnd[key] != new_snd_wnd) ){
+			snd_wnd[key] = new_snd_wnd
+			packet_updated = 1
+		}
+	}
+
+	if ( srtt_flg ) {
+		new_srtt = @cast(sk, "tcp_sock")->srtt
+		if( always_update || (srtt[key] != new_srtt) ){
+			srtt[key] = new_srtt
+			packet_updated = 1
+		}
+	}
+
+	if( ssthresh_flg ) {
+		new_ssthresh = tcp_current_ssthresh(sk)
+		if( always_update || (ssthresh[key] != new_ssthresh) ){
+			ssthresh[key] = new_ssthresh
+			packet_updated = 1
+		}
+	}
+
+	if ( rcvwnd_flg ) {
+		new_rcvwnd = @cast(sk, "tcp_sock")->rcv_wnd
+		if( always_update || (rcvwnd[key] != new_rcvwnd) ){
+			rcvwnd[key] = new_rcvwnd
+			packet_updated = 1
+		}
+	}
+
+	return packet_updated
+}
+
+/*
+ * copied from:
+ * include/net/tcp.h:tcp_current_ssthresh()
+ */
+function tcp_current_ssthresh(sk:long)
+{
+	if ((1 << @cast(sk, "inet_connection_sock")->icsk_ca_state) &
+						((1 << 2) | (1 << 3))){
+		return @cast(sk, "tcp_sock")->snd_ssthresh
+	}else{
+		return netmax(@cast(sk, "tcp_sock")->snd_ssthresh,
+				((@cast(sk, "tcp_sock")->snd_cwnd >>1)+
+				(@cast(sk, "tcp_sock")->snd_cwnd >> 2)))
+	}
+}
+
+function netmax:long (val1:long, val2:long)
+{
+	if(val1 > val2)
+		return val1
+	else
+		return val2
+}
+
+/* All command line arguments other than the address rules are processed
+ * first and must be placed on the command line prior to any address rules.
+ */
+function process_cmdline:long ()
+{
+        filter_number = 0
+        for (i=1; i <= argc; i++) {
+                argument = tokenize(argv[i], "=")
+
+		if (argument == "help")
+			usage("")
+
+                if (argument == "filter") {
+			filter_given=1;
+                        argv[i]=""
+                        while(strlen(byte = tokenize(argv[i], ",")) != 0) {
+                                argv[i] = ""
+				if ( byte == "snd_cwnd" ) {
+					snd_cwnd_flg = 1; continue };
+				if ( byte == "snd_wnd" ) {
+					snd_wnd_flg = 1;  continue };
+				if ( byte == "srtt" ) {
+					srtt_flg = 1;  continue };
+				if ( byte == "state" ) {
+					state_flg = 1;  continue };
+				if ( byte == "txq" ) {
+					txq_flg = 1;  continue };
+				if ( byte == "rxq" ) {
+					rxq_flg = 1;  continue };
+				if ( byte == "rexmit" ) {
+					rexmit_flg = 1;  continue };
+				if ( byte == "pmtu" ) {
+					pmtu_flg = 1;  continue };
+				if ( byte == "ssthresh" ) {
+					ssthresh_flg = 1;  continue };
+				if ( byte == "timer" ) {
+					timer_flg = 1;  continue };
+				if ( byte == "rcvwnd" ) {
+					rcvwnd_flg = 1;  continue };
+				if ( byte == "length" ) {
+					length_flg = 1; continue };
+				if ( byte == "all" ) {
+					snd_cwnd_flg = snd_wnd_flg = srtt_flg =
+					state_flg = txq_flg = rxq_flg =
+					rexmit_flg = pmtu_flg = ssthresh_flg =
+					timer_flg = rcvwnd_flg = length_flg = 1;
+					continue
+				};
+				usage("Unknown filter value given!")
+                        }
+                        continue;
+                }
+
+                if ( argument == "timeout" ){
+                        argv[i]=""
+                        timeout=strtol(tokenize(argv[i], "="),10)
+                        continue;
+                }
+
+		if ( argument == "update") {
+			argv[i]=""
+			update_disp = tokenize(argv[i], "=")
+			if (update_disp == "all")
+				always_update = 1;
+			continue;
+		}
+
+		/* Anything on the command line after this point must
+		 * be an address rule.
+		 */
+		source = tokenize(argv[i], "-")
+			argv[i] = ""
+		dest = tokenize(argv[i], "-")
+
+		source_addr = tokenize(source, ":")
+			source=""
+		source_port = tokenize(source, ":")
+
+		dest_addr = tokenize(dest, ":")
+			dest=""
+		dest_port = tokenize(dest, ":")
+
+		/* stap bug */
+		if ( dest_port == "fobar") i=i;
+
+		++filter_number;
+		j=filter_number*6;
+		filter[j]   = ipv4_pton(source_addr,0)  // Source address
+		filter[j+1] = ipv4_pton(source_addr,1)  // Source address mask
+		filter[j+2] = ipv4_portton(source_port) // Source port
+		filter[j+3] = ipv4_pton(dest_addr,0)    // Dest address
+		filter[j+4] = ipv4_pton(dest_addr,1)    // Dest address mask
+		filter[j+5] = ipv4_portton(dest_port)   // Dest port
+
+		if (filter[j]< -1 ||
+			filter[j+1] < -1 ||
+			filter[j+2] < -1 ||
+			filter[j+3] < -1 ||
+			filter[j+4] < -1 ||
+			filter[j+5] < -1 ) return -1;
+
+	}
+
+	/* default filter is all */
+	if ( !filter_given )
+		snd_cwnd_flg = snd_wnd_flg = srtt_flg =
+		state_flg = txq_flg = rxq_flg =
+		rexmit_flg = pmtu_flg = ssthresh_flg =
+		timer_flg = rcvwnd_flg = length_flg = 1;
+
+	return filter_number;
+}
+
+/*
+ * Convert an ascii integer values between 0 and 65534 to a u16 port number.
+ * "*" are treated as wildcards and will be converted to -1.
+ */
+function ipv4_portton:long (port:string)
+{
+	if ( port == "*" )
+		return -1;
+
+	pport=strtol(port,10);
+
+	if ( pport > 0xffff ){
+		printf("Bad port number %s\n",port)
+		return -22;
+	}
+
+	return pport
+}
+
+/*
+ * Convert ipv4 dot notation address into longs.
+ * Supports "*" in any field treating it as a wildcard by making the byte=0.
+ * If make_mask is set it creates a mask based on the "*" fields. All non='*'
+ * bytes are set to 0xff all * fields are set to 0x0;.
+ */
+function ipv4_pton:long (addr:string, make_mask:long)
+{
+	i=32;
+	ip=0;
+	ips=addr;
+	while(strlen(byte = tokenize(ips, ".")) != 0) {
+		i-=8;
+		ips="";
+
+		if ( byte == "*" ){
+			byte = "0"
+		} else {
+			if ( make_mask ) byte = "255";
+		}
+
+		j=strtol(byte,10);
+		if ( j > 255 ){
+			printf("bad address %s\n",addr)
+			return -22;
+		}
+			ip=ip+(j<<i) // left shift the byte into the address
+	}
+	if ( i != 0 ){
+		printf("bad address %s\n",addr)
+		return -22;
+	}
+	return ip;
+}
+
+/*
+ * Returns a unique value (stored in the global key_list) based on the socket
+ * address tuple. A new value is created if one does not already exist.
+ */
+function build_key:long (laddr:long, raddr:long, lport:long, rport:long)
+{
+	if ( key_list[laddr, raddr, lport, rport] )
+		return  key_list[laddr, raddr, lport, rport]
+	else
+		return key_list[laddr, raddr, lport, rport] = ++lastkey
+}
+
+/*
+ * Checks the tuple against the rule list. If we pass through the rule
+ * then return a unique key value, otherwise return zero.
+ */
+function filter_key:long (sk:long)
+{
+	laddr = tcpmib_local_addr(sk);
+	raddr = tcpmib_remote_addr(sk);
+	lport = tcpmib_local_port(sk);
+	rport = tcpmib_remote_port(sk);
+
+	for (i=1; i <= number_of_rules; i++){
+		j=i*6;
+
+		// Local filter
+		local_filter=remote_filter=0;
+		if ( (laddr&filter[j+1]) == filter[j] ) {
+			if ( (filter[j+2] == -1 ) || (lport == filter[j+2]))
+				local_filter = 1;
+		}
+		// Remote filter
+		if ( (raddr&filter[j+4]) == filter[j+3] ) {
+			if ( (filter[j+5] == -1 ) || (rport == filter[j+5]))
+				remote_filter = 1;
+		}
+		if(local_filter && remote_filter){
+			return build_key(laddr, raddr, lport, rport);
+		}
+	}
+	return 0;
+}
+
+/* Free up a slot in the data arrays */
+function clean_up (key:long)
+{
+	foreach ( [laddr, raddr, lport, rport] in key_list ){
+		if ( key_list[laddr, raddr, lport, rport] == key ){
+			break
+		}
+	}
+
+	delete key_list[laddr, raddr, lport, rport]
+
+	if (snd_cwnd_flg) delete snd_cwnd[key];
+	if (snd_wnd_flg) delete snd_wnd[key];
+	if (srtt_flg) delete srtt[key];
+	if (state_flg) delete state[key];
+	if (txq_flg) delete txq[key];
+	if (rxq_flg) delete rxq[key];
+	if (rexmit_flg) delete rexmit[key];
+	if (pmtu_flg) delete pmtu[key];
+	if (ssthresh_flg) delete ssthresh[key];
+	if ( timer_flg ) {
+		delete tx_timer[key];
+		delete find_timer[key];
+	}
+	if (rcvwnd_flg) delete rcvwnd[key];
+	delete length[key];
+}
+
+/* Terminates the run in timeout seconds, using global timeout value */
+probe timer.s(1) {
+	if ( timeout == -1 ) next
+	if ( !--timeout ) exit()
+}
+
+function usage (msg:string)
+{
+	printf("\nUsage:\n");
+	printf("\ttcp_trace.stp  filter=<list of filters>[timeout=<sec>] \n");
+	printf("\t\t\t[update=change|all] Rule\n\n");
+	printf("\tRule format:");
+	printf("<local address>:<local-port>-<remote address>:<remote-port>\n");
+	printf("\tFilter values: all|state|txq|rxq|srtt|snd_cwnd|snd_wnd|\n");
+	printf("\t\t\trexmit|pmtu|ssthresh|timer|rcvwnd\n\n");
+	printf("%s\n\n",msg);
+	error(msg);
+}
diff --git a/testsuite/systemtap.examples/network/tcp_trace.txt b/testsuite/systemtap.examples/network/tcp_trace.txt
new file mode 100644
index 00000000..3b2da39e
--- /dev/null
+++ b/testsuite/systemtap.examples/network/tcp_trace.txt
@@ -0,0 +1,26 @@
+$ ./tcp_trace.stp  *.*.*.*:80-*.*.*.*:*
+Start TCP Probing.....
+
+Source Address        Dest Address          State       Timer       Tx-Q    Rx-Q    PMTU SndCwnd  SndWnd  RcvWnd    SSRT   Ssthreshold  Rexmit  Length
+0.0.0.0:0             0.0.0.0:80            LISTEN                   128       0       0       2       0       0       0    2147483647       0      40
+192.168.1.104:41060   192.168.1.201:80      SYN_RECV                   0       0    1500       2    5888    5792       0    2147483647       0     488
+192.168.1.201:80      192.168.1.104:41060   ESTABLISHED                0     456    1500       3    5888    5792       8    2147483647       0
+192.168.1.201:80      192.168.1.104:41060   ESTABLISHED             2896       0    1500       3    5888    6880       8    2147483647       0    2896
+192.168.1.201:80      192.168.1.104:41060   ESTABLISHED             4116       0    1500       3    5888    6880       8    2147483647       0    1220
+192.168.1.201:80      192.168.1.104:41060   FIN_WAIT1               4117       0    1500       3    5888    6880       8    2147483647       0
+192.168.1.104:41060   192.168.1.201:80      FIN_WAIT1               2669       0    1500       4    8832    6880       8    2147483647       0      32
+192.168.1.104:41060   192.168.1.201:80      FIN_WAIT1               1221       0    1500       5   11648    6880       8    2147483647       0      32
+192.168.1.104:41060   192.168.1.201:80      FIN_WAIT1                  1       0    1500       6   14592    6880       8    2147483647       0      32
+192.168.1.201:80      192.168.1.104:41060   FIN_WAIT2                  0       1    1500       6   14592    6880       8    2147483647       0
+192.168.1.104:41061   192.168.1.201:80      SYN_RECV                   0       0    1500       2    5888    5792       0    2147483647       0     552
+192.168.1.201:80      192.168.1.104:41061   ESTABLISHED                0     520    1500       3    5888    5792       8    2147483647       0
+192.168.1.104:41062   192.168.1.201:80      SYN_RECV                   0       0    1500       2    5888    5792       0    2147483647       0     551
+192.168.1.201:80      192.168.1.104:41062   ESTABLISHED                0     519    1500       3    5888    5792       8    2147483647       0
+192.168.1.201:80      192.168.1.104:41061   ESTABLISHED              150       0    1500       3    5888    6880       8    2147483647       0     150
+192.168.1.201:80      192.168.1.104:41062   ESTABLISHED              150       0    1500       3    5888    6880       8    2147483647       0     150
+192.168.1.201:80      192.168.1.104:41061   FIN_WAIT1                151       0    1500       3    5888    6880       8    2147483647       0
+192.168.1.201:80      192.168.1.104:41062   FIN_WAIT1                151       0    1500       3    5888    6880       8    2147483647       0
+192.168.1.104:41061   192.168.1.201:80      FIN_WAIT1                  1       0    1500       4    6912    6880       8    2147483647       0      32
+192.168.1.201:80      192.168.1.104:41061   FIN_WAIT2                  0       1    1500       5    6912    6880       8    2147483647       0
+192.168.1.104:41062   192.168.1.201:80      FIN_WAIT1                  1       0    1500       4    6912    6880       8    2147483647       0      32
+192.168.1.201:80      192.168.1.104:41062   FIN_WAIT2                  0       1    1500       5    6912    6880       8    2147483647       0
-- 
cgit