NDT-DEV email list created

Revision: 737
Author:   

Date:     Tue Oct 25 13:58:59 2011
Log:      Refactored and added inline comments for web100clt.c; new files  
test_results_clt to contain clt test results heuristics, miscellaneous  
constants added and minor additions in other files
http://code.google.com/p/ndt/source/detail?r=737

Added:
 /branches/kkumar_code_organize/src/test_results_clt.c
 /branches/kkumar_code_organize/src/test_results_clt.h
Modified:
 /branches/kkumar_code_organize/src/clt_tests.h
 /branches/kkumar_code_organize/src/protocol.h
 /branches/kkumar_code_organize/src/test_c2s_clt.c
 /branches/kkumar_code_organize/src/test_mid_clt.c
 /branches/kkumar_code_organize/src/test_s2c_clt.c
 /branches/kkumar_code_organize/src/test_sfw_clt.c
 /branches/kkumar_code_organize/src/utils.h
 /branches/kkumar_code_organize/src/web100clt.c

=======================================
--- /dev/null
+++ /branches/kkumar_code_organize/src/test_results_clt.c	Tue Oct 25  
13:58:59 2011
@@ -0,0 +1,480 @@
+/**
+ * This file contains methods to interpret the results sent to the CLT  
from the server.
+ *
+ *  Created on: Oct 19, 2011
+ *      Author: 

+ *
+ */
+
+#include <string.h>
+#include <stdio.h>
+
+#include "logging.h"
+#include "utils.h"
+#include "clt_tests.h"
+#include "test_results_clt.h"
+
+#ifndef VIEW_DIFF
+#define VIEW_DIFF 0.1
+#endif
+
+/** Get link speed based on data sent from server.
+ * This data is an integral value from among a set indicative of link  
speeds.
+ * @param c2s_linkspeed_ind
+ * @return Current link's speed
+ */
+double get_linkspeed(int c2s_linkspeed_ind, int half_duplex_ind) {
+       double mylinkspeed = 0;
+       if (c2s_linkspeed_ind < DATA_RATE_ETHERNET) {
+               if (c2s_linkspeed_ind < DATA_RATE_RTT) {
+                       printf("Server unable to determine bottleneck link 
type.\n");
+               } else {
+                       printf("Your host is connected to a ");
+
+                       if (c2s_linkspeed_ind == DATA_RATE_DIAL_UP) {
+                               printf("Dial-up Modem\n");
+                               mylinkspeed = .064;
+                       } else {
+                               printf("Cable/DSL modem\n");
+                               mylinkspeed = 2;
+                       }
+               }
+       } else {
+               printf("The slowest link in the end-to-end path is a ");
+
+               if (c2s_linkspeed_ind == DATA_RATE_ETHERNET) {
+                       printf("10 Mbps Ethernet or WiFi 11b subnet\n");
+                       mylinkspeed = 10;
+               } else if (c2s_linkspeed_ind == DATA_RATE_T3) {
+                       printf("45 Mbps T3/DS3 or WiFi 11 a/g  subnet\n");
+                       mylinkspeed = 45;
+               } else if (c2s_linkspeed_ind == DATA_RATE_FAST_ETHERNET) {
+                       printf("100 Mbps ");
+                       mylinkspeed = 100;
+                       if (half_duplex_ind == NO_HALF_DUPLEX) {
+                               printf("Full duplex Fast Ethernet subnet\n");
+                       } else {
+                               printf("Half duplex Fast Ethernet subnet\n");
+                       }
+               } else if (c2s_linkspeed_ind == DATA_RATE_OC_12) {
+                       printf("a 622 Mbps OC-12 subnet\n");
+                       mylinkspeed = 622;
+               } else if (c2s_linkspeed_ind == DATA_RATE_GIGABIT_ETHERNET) {
+                       printf("1.0 Gbps Gigabit Ethernet subnet\n");
+                       mylinkspeed = 1000;
+               } else if (c2s_linkspeed_ind == DATA_RATE_OC_48) {
+                       printf("2.4 Gbps OC-48 subnet\n");
+                       mylinkspeed = 2400;
+               } else if (c2s_linkspeed_ind == DATA_RATE_10G_ETHERNET) {
+                       printf("10 Gbps 10 Gigabit Ethernet/OC-192 subnet\n");
+                       mylinkspeed = 10000;
+               }
+       }
+       return mylinkspeed;
+}
+
+/**
+ * Print results of the mismatch detection
+ * @param mismatch Integer indicating results
+ */
+void print_results_mismatchcheck(int mismatch) {
+       switch (mismatch) {
+       case DUPLEX_OLD_ALGO_INDICATOR :
+               printf("Warning: Old Duplex-Mismatch condition detected.\n");
+               break;
+
+       case DUPLEX_SWITCH_FULL_HOST_HALF :
+		printf("Alarm: Duplex Mismatch condition detected. Switch=Full and  
Host=Half\n");
+               break;
+       case DUPLEX_SWITCH_FULL_HOST_HALF_POSS:
+               printf(
+				"Alarm: Possible Duplex Mismatch condition detected. Switch=Full and  
Host=Half\n");
+               break;
+       case DUPLEX_SWITCH_HALF_HOST_FULL:
+               printf(
+				"Alarm: Duplex Mismatch condition detected. Switch=Half and  
Host=Full\n");
+               break;
+       case DUPLEX_SWITCH_HALF_HOST_FULL_POSS:
+               printf(
+				"Alarm: Possible Duplex Mismatch condition detected. Switch=Half and  
Host=Full\n");
+               break;
+       case DUPLEX_SWITCH_HALF_HOST_FULL_WARN:
+               printf(
+				"Warning: Possible Duplex Mismatch condition detected. Switch=Half and  
Host=Full\n");
+               break;
+       }
+}
+
+
+/**
+ * Calculate and display recommended buffer sizes based on
+ * receive window size, the max Receive window advertisement
+ * received, link speed and round trip time.
+ * @param rwin
+ * @param rttsec
+ * @param avgrtt
+ * @param mylink
+ * @param max_RwinRcvd
+ */
+void print_recommend_buffersize(double rwin, double rttsec, double avgrtt,
+               double mylink, int max_RwinRcvd){
+       int j = 0;
+	log_print(3, "Is larger buffer recommended?  rwin*2/rttsec (%0.4f) <  
mylink (%0.4f) ",
+                       ((rwin*2)/rttsec), mylink);
+       log_println(3, "AND j (%0.4f) > MaxRwinRcvd (%d)",
+                       (float)((mylink * avgrtt)*1000)/8, max_RwinRcvd);
+       if (((rwin*2)/rttsec) < mylink) {
+               j = (float)((mylink * avgrtt)*1000) / 8;
+               if ((int)j > max_RwinRcvd) {
+                       printf("Information: The receive buffer should be %0.0f 
", j/1024);
+                       printf("kbytes to maximize throughput\n");
+               }
+       }
+}
+
+/**
+ * Check if faulty hardware was detected, and print results
+ * @param is_badcable
+ * */
+void check_badcable(int is_bad_cable) {
+       if (is_bad_cable == POSSIBLE_BAD_CABLE) {
+               printf("Alarm: Excessive errors, check network cable(s).\n");
+       }
+}
+
+/**
+ * Check if congestion was detected, and print results
+ * @param is_congested
+ * */
+void check_congestion(int is_congested) {
+       if (is_congested == POSSIBLE_CONGESTION) {
+        printf("Information: Other network traffic is congesting the  
link\n");
+       }
+}
+
+/**
+ * Check if packet queuing is a problem at the C->S end.
+ * @param c2sthruput The C->S throughput as calculated by the server in  
the C->S test
+ * @param spdout C->S throughput as calculated by the Client during the  
C->S test
+ * @param sndqueue length of send queue of the C->S throughput test
+ */
+void check_C2Spacketqueuing(double c2sthruput, double spdout, int  
sndqueue, int pktcount, int buflength) {
+       if (c2sthruput < (spdout * (1.0 - VIEW_DIFF))) {
+               printf("Information [C2S]: Packet queuing detected: %0.2f%% ",
+                               100 * (spdout - c2sthruput) / spdout);
+		if (sndqueue > (0.8 * pktcount * buflength * (spdout - c2sthruput) /  
spdout)) {
+                       printf("(local buffers)\n");
+               } else {
+                       printf("(remote buffers)\n");
+               }
+       }
+}
+
+
+/**
+ * Deduce if packet queuing is a problem at the S->C end from values  
collected
+ *  during the S2C tests.
+ * @param s2cthroughput The S->C throughput as calculated by the client
+ * @param spdin S->C throughput as calculated by the Client during the  
C->S test
+ * @param sndqueue length of send queue of the S->C throughput test
+ * @param sbytecount total-sent-byte-count in the S->C throughput test
+ */
+void check_S2Cpacketqueuing(double s2cthroughput, double spdin, int  
srvsndqueue, int sbytecount) {
+       if (spdin < (s2cthroughput * (1.0 - VIEW_DIFF))) {
+               printf("Information [S2C]: Packet queuing detected: %0.2f%% ",
+                               100 * (s2cthroughput - spdin) / 
s2cthroughput);
+		if (srvsndqueue > (0.8 * sbytecount * (s2cthroughput - spdin) /  
s2cthroughput)) {
+                       printf("(local buffers)\n");
+               } else {
+                       printf("(remote buffers)\n");
+               }
+       }
+}
+
+/**
+ *  Print suggestions based on packet loss/retransmissions details obtained
+ *
+ * If there were packets retransmitted, print details about :
+ * - whether packets arrived out of order
+ * -# of times the retransmit timeout expired
+ * -total time spent waiting
+ *
+ * If there were no packet retransmissions, but duplicate
+ * acknowledgments were received, print details about:
+ * - whether packets arrived out of order
+ *
+ * @param PktsRetrans Number of packet retransmissions
+ * @param DupAcksIn   Number of incoming duplicate acknowledgments
+ * @param SACKsRcvd   number of SACK options
+ * @param ooorder     out-of-order packets
+ * @param Timeouts       number of times retransmit timer expired
+ * @param waitsec     total idle time
+ * @param totaltesttime     Total test time
+ */
+void print_packetloss_statistics(int PktsRetrans, int DupAcksIn, int  
SACKsRcvd,
+               double ooorder, int Timeouts, double waitsec , double 
totaltesttime) {
+
+       if (PktsRetrans > 0) {
+               printf("There were %d packets retransmitted", PktsRetrans);
+               printf(", %d duplicate acks received", DupAcksIn);
+               printf(", and %d SACK blocks received\n", SACKsRcvd);
+               if (ooorder > 0)
+                       printf("Packets arrived out-of-order %0.2f%% of the 
time.\n",
+                                       ooorder * 100);
+               if (Timeouts > 0)
+                       printf("The connection stalled %d times due to packet 
loss.\n",
+                                       Timeouts);
+               if (waitsec > 0)
+                       printf(
+                                       "The connection was idle %0.2f seconds 
(%0.2f%%) of the time.\n",
+                                       waitsec, (100 * waitsec / 
totaltesttime));
+       } else if (DupAcksIn > 0) {
+               printf("No packet loss - ");
+               if (ooorder > 0)
+                       printf("but packets arrived out-of-order %0.2f%% of the 
time.\n",
+                                       ooorder * 100);
+               else
+                       printf("\n");
+       } else {
+               printf("No packet loss was observed.\n");
+       }
+
+}
+
+
+
+/**
+ * Print details about being receiver, sender or congestion window limited.
+ * @param rwintime  time spent limited due to receive window limitations
+ * @param rwin         receive window size
+ * @param sendtime  time spent limited due to send window limitations
+ * @param swin         send window size
+ * @param cwndtime  time spent limited due to congestion window limitations
+ * @param rttsec       round-trip time in sec
+ * @param mylinkspeed Link speed
+ * @param sndbuf       send buffer size
+ * @param max_rwinrcvd MaxRwinRcvd value
+ */
+
+void print_limitedtime_ratio(double rwintime, double rwin, double  
sendtime, double swin, double cwndtime,
+               double rttsec, double mylinkspeed, int sndbuf, int 
max_rwinrcvd) {
+
+       if (rwintime > .015) {
+               printf("This connection is receiver limited %0.2f%% of the 
time.\n",
+                               rwintime * 100);
+               if ((2 * (rwin / rttsec)) < mylinkspeed)
+                       printf(
+					"  Increasing the current receive buffer (%0.2f KB) will improve  
performance\n",
+                                       (float) max_rwinrcvd / KILO_BITS);
+       }
+       if (sendtime > .015) {
+               printf("This connection is sender limited %0.2f%% of the 
time.\n",
+                               sendtime * 100);
+               if ((2 * (swin / rttsec)) < mylinkspeed)
+                       printf(
+					"  Increasing the current send buffer (%0.2f KB) will improve  
performance\n",
+                                       (float) sndbuf / KILO_BITS);
+       }
+       if (cwndtime > .005) {
+               printf("This connection is network limited %0.2f%% of the 
time.\n",
+                               cwndtime * 100);
+       }
+
+}
+
+/**
+ * Check if excessive packet loss is affecting performance
+ * @param spd throughput indicator
+ * @param loss packet loss
+ */
+void print_packetloss_excess(double spd, double loss) {
+       if ((spd < 4) && (loss > .01)) {
+               printf(
+                               "Excessive packet loss is impacting your 
performance, check the ");
+               printf("auto-negotiate function on your local PC and network 
switch\n");
+       }
+}
+
+/**
+ * Print if TCP Selective Acknowledgment Options based on RFC 2018 is on
+ *
+ * @param SACKEnabled
+ */
+void print_SAck_RFC2018(int SACKEnabled) {
+       printf("RFC 2018 Selective Acknowledgment: ");
+       if (SACKEnabled == 0)
+               printf("OFF\n");
+       else
+               printf("ON\n");
+}
+
+/**
+ * Print if Nagle algorithm (rfc 896) is on
+ * @param is_nagleenabled
+ */
+
+void print_Nagle_RFC896(int is_nagleenabled)
+{
+       printf("RFC 896 Nagle Algorithm: ");
+       if (is_nagleenabled == 0)
+               printf("OFF\n");
+       else
+               printf("ON\n");
+}
+
+/**
+ * Print if Explicit congestion notification to IP is on - RFC 3168 related
+ * @param is_ECNenabled
+ */
+void print_congestion_RFC3168(int is_ECNenabled)
+{
+       printf("RFC 3168 Explicit Congestion Notification: ");
+                               if (is_ECNenabled == 0)
+                                       printf("OFF\n");
+                               else
+                                       printf("ON\n");
+
+}
+
+/**
+ * Print details of whether time stamping is on - RFC 1323 related.
+ *
+ * @param is_timestampenabled
+ */
+void print_timestamping_RFC1323(int is_timestampenabled)
+{
+       printf("RFC 1323 Time Stamping: ");
+       if (is_timestampenabled == 0)
+               printf("OFF\n");
+       else
+               printf("ON\n");
+}
+
+/**
+ * Print window scaling based data
+ * @param max_rwinrcvd         MaxRwinRcvd web100 var value
+ * @param winscale_rcvd value of the received window scale option
+ * @param winscale_sent value of the transmitted window scale option
+ */
+void print_windowscaling(int max_rwinrcvd, int winscale_rcvd, int  
winscale_sent) {
+       printf("RFC 1323 Window Scaling: ");
+       if (max_rwinrcvd < 65535)
+               winscale_rcvd = 0;
+
+       if ((winscale_rcvd == 0) || (winscale_rcvd > 20))
+               printf("OFF\n");
+       else
+               printf("ON; Scaling Factors - Server=%d, Client=%d\n",
+                               winscale_rcvd, winscale_sent);
+}
+
+/**
+ * Print details of throughput limits(thresholds) imposed by
+ *             the send, receive or congestion window values
+ * @param max_rwinrcvd         MaxRwinRcvd web100 var value
+ * @param rcvwinscale Value of receive window scale
+ * @param sndbuf send buffer size
+ * @param rwin   Receive window value in bytes
+ * @param swin   Send window value in bytes
+ * @param cwin   congestion window value in bytes
+ * @param rttsec total round-trip time
+ * @param estimate Estimated theoretical throughput
+ */
+void print_throughputlimits(int max_rwinrcvd, int rcvwinscale, int *sndbuf,
+		double s_win, double r_win, double c_win, double rttsec, double  
estimate) {
+       int tempsendbuf = *sndbuf;
+       if ((rcvwinscale == 0) && (tempsendbuf > 65535))
+               tempsendbuf = 65535;
+
+       printf("The theoretical network limit is %0.2f Mbps\n", estimate);
+
+       printf(
+			"The NDT server has a %0.0f KByte buffer which limits the throughput  
to %0.2f Mbps\n",
+                       (float) tempsendbuf / KILO_BITS, (float) s_win / 
rttsec);
+
+       printf(
+			"Your PC/Workstation has a %0.0f KByte buffer which limits the  
throughput to %0.2f Mbps\n",
+                       (float) max_rwinrcvd / KILO_BITS, (float) r_win / 
rttsec);
+
+       printf(
+                       "The network based flow control limits the throughput to 
%0.2f Mbps\n",
+                       (float) c_win / rttsec);
+
+}
+
+
+/**
+ * Print details of link speed as seen by data and ack speed indicators
+ *
+ * @param isC2S_enabled Has C2S test been performed?
+ * @param c2s_linkspeed_data Data link speed as detected by server data
+ * @param c2s_linkspeed_ack Data link speed(type) as detected by server  
acknowledgments
+ * @param s2c_linkspeed_data Data link speed as detected by client data
+ * @param s2c_linkspeed_ack Data link speed as detected by client  
acknowledgments
+ */
+void print_linkspeed_dataacks(int isC2S_enabled, int c2s_linkspeed_data,
+               int c2s_linkspeed_ack, int s2c_linkspeed_data, int 
s2c_linkspeed_ack) {
+       if (isC2S_enabled) {
+               printf(
+				"\nClient Data reports link is '%3d', Client Acks report link  
is '%3d'\n",
+                               c2s_linkspeed_data, c2s_linkspeed_ack);
+       }
+       printf(
+                       "Server Data reports link is '%3d', Server Acks report 
link is '%3d'\n",
+                       s2c_linkspeed_data, s2c_linkspeed_ack);
+
+}
+
+/**
+ * A Network Address Translation (NAT) box is detected by
+ *  comparing the client/server IP addresses as seen from the server and  
the client boxes.
+ * @param ssip Server side IP address string
+ * @param csip Client side sersver IP address string
+ * @param scip Server side client IP address string
+ * @param ccip Client side client IP address string
+ */
+void check_NAT(char *ssip, char *csip, char *scip, char *ccip) {
+
+       // If server and client both see similar server IP addresses,
+       // no NAT happening
+       if (strcmp(ssip, csip) == 0)
+               printf("Server IP addresses are preserved End-to-End\n");
+       else {
+               printf("Information: Network Address Translation (NAT) box is 
");
+               printf("modifying the Server's IP address\n");
+               printf("\tServer says [%s] but Client says [ %s]\n", ssip, 
csip);
+       }
+
+       // If server and client both see similar client IP addresses,
+       // no NAT happening
+       if (strcmp(scip, ccip) == 0)
+               printf("Client IP addresses are preserved End-to-End\n");
+       else {
+               printf("Information: Network Address Translation (NAT) box is 
");
+               printf("modifying the Client's IP address\n");
+               printf("\tServer says [%s] but Client says [ %s]\n", scip, 
ccip);
+       }
+
+}
+
+/**
+ * Check packet size preservation by comparing the final value
+ *  of the MSS variable in the Middlebox test.
+ *
+ * Note that the server sets the MSS value to 1456 on the listening socket
+ *   before the NDT Client connects to it; the final value of the MSS
+ *   variable is read after the NDT Client connects.
+ * @param is_timestampenabled
+ * @param mssvalue
+ */
+void check_MSS_modification(int is_timestampenabled, int *mssvalue) {
+       if (is_timestampenabled == 1)
+               *mssvalue += 12;
+               if (*mssvalue == 1456)
+                       printf("Packet size is preserved End-to-End\n");
+               else
+                       printf(
+					"Information: Network Middlebox is modifying MSS variable (changed  
to %d)\n",
+                                       *mssvalue);
+
+}
=======================================
--- /dev/null
+++ /branches/kkumar_code_organize/src/test_results_clt.h	Tue Oct 25  
13:58:59 2011
@@ -0,0 +1,82 @@
+/*
+ * test_results_clt.h
+ *
+ *  Created on: Oct 19, 2011
+ *      Author: kkumar
+ */
+
+#ifndef TEST_RESULTS_CLT_H_
+#define TEST_RESULTS_CLT_H_
+
+// determine linkspeed based on link speed indicator
+double get_linkspeed(int c2s_linkspeed_ind, int half_duplex_ind);
+
+// Check if faulty hardware was detected
+void check_badcable(int is_bad_able);
+
+// Check if congestion was detected, and print results
+void check_congestion(int is_congested);
+
+// Print results of the mismatch detection
+void print_results_mismatchcheck(int mismatch);
+
+// Calculate and display recommended buffer sizes
+void print_recommend_buffersize(double rwin, double rttsec, double avgrtt,
+ double mylink, int max_RwinRcvd);
+
+// Check if faulty hardware was detected, and print results
+void check_badcable(int is_bad_cable);
+
+// Check if congestion was detected, and print results
+void check_congestion(int is_congested);
+
+// Check if packet queuing is a problem at the C->S end.
+void check_C2Spacketqueuing(double c2sthruput, double spdout, int  
sndqueue, int pktcount, int buflength);
+
+//  Deduce if packet queuing is a problem at the S->C end from values  
collected
+//  .. during the S2C tests.
+void check_S2Cpacketqueuing(double s2cthroughput, double spdin, int  
srvsndqueue, int sbytecount);
+
+// Print suggestions based on packet loss/retransmissions details obtained
+void print_packetloss_statistics(int PktsRetrans, int DupAcksIn, int  
SACKsRcvd,
+               double ooorder, int Timeouts, double waitsec , double 
totaltesttime);
+
+// Print details about being receiver, sender or congestion window limited.
+void print_limitedtime_ratio(double rwintime, double rwin, double  
sendtime, double swin, double cwndtime,
+               double rttsec, double mylinkspeed, int sndbuf, int 
max_rwinrcvd) ;
+
+// Check if excessive packet loss is affecting performance
+void print_packetloss_excess(double spd, double loss);
+
+// Print if TCP Selective Acknowledgment Options based on RFC 2018 is on
+void print_SAck_RFC2018(int SACKEnabled);
+
+// Print if Nagle algorithm (rfc 896) is on
+void print_Nagle_RFC896(int is_nagleenabled);
+
+//  Print if Explicit congestion notification to IP is on - RFC 3168  
related
+void print_congestion_RFC3168(int is_ECNenabled);
+
+// Print details of whether time stamping is on - RFC 1323 based.
+void print_timestamping_RFC1323(int is_timestampenabled);
+
+// Print window scaling based data
+void print_windowscaling(int MaxRwinRcvd, int WinScaleRcvd, int  
WinScaleSent);
+
+//Print details of throughput limits(thresholds) imposed by
+//             the send, receive or congestion window values
+void print_throughputlimits(int max_rwinrcvd, int RcvWinScale,
+               int *sndbuf, double s_win, double r_win, double c_win, double 
rttsec,
+               double estimate);
+
+// Print details of link speed as seen by data and ack speed indicators
+void print_linkspeed_dataacks(int isC2S_enabled, int c2s_linkspeed_data,
+               int c2s_linkspeed_ack, int s2c_linkspeed_data, int 
s2c_linkspeed_ack) ;
+
+// Check if a Network Address translation box is modifying IP addresses
+// of server or client
+void check_NAT(char *ssip, char *csip, char *scip, char *ccip);
+
+// Check packet size preservation
+void check_MSS_modification(int is_timestampenabled, int *mssvalue);
+#endif /* TEST_RESULTS_CLT_H_ */
=======================================
--- /branches/kkumar_code_organize/src/clt_tests.h      Sun Oct 23 19:27:44 
2011
+++ /branches/kkumar_code_organize/src/clt_tests.h      Tue Oct 25 13:58:59 
2011
@@ -10,6 +10,8 @@
 #define _JS_CLT_TESTS_H

 #define MIDBOX_TEST_LOG "Middlebox test"
+#define S2C_TEST_LOG "S2C throughput test"
+#define MIDBOX_TEST_RES_SIZE 512

 int test_mid_clt(int ctlSocket, char tests, char* host, int conn_options,
                int buf_size, char* tmpstr2);
=======================================
--- /branches/kkumar_code_organize/src/protocol.h       Mon Oct 17 06:43:25 
2011
+++ /branches/kkumar_code_organize/src/protocol.h       Tue Oct 25 13:58:59 
2011
@@ -24,6 +24,12 @@
 #define MSG_LOGOUT 9
 #define MSG_WAITING 10

+#define SRV_QUEUE_TEST_STARTS_NOW  0
+#define SRV_QUEUE_SERVER_FAULT 9977
+#define SRV_QUEUE_SERVER_BUSY 9988
+#define SRV_QUEUE_HEARTBEAT 9990
+#define SRV_QUEUE_SERVER_BUSY_60s 9999
+
 /*
  #define TEST_NONE 0
  #define TEST_MID (1L << 0)
=======================================
--- /branches/kkumar_code_organize/src/test_c2s_clt.c	Sun Oct 23 19:27:44  
2011
+++ /branches/kkumar_code_organize/src/test_c2s_clt.c	Tue Oct 25 13:58:59  
2011
@@ -44,10 +44,13 @@
 int test_c2s_clt(int ctlSocket, char tests, char* host, int conn_options,
                int buf_size) {
        /* char buff[BUFFSIZE+1]; */
-	char buff[64 * KILO_BITS]; // message payload. Todo size variations  
between server and CLT?
+       char buff[64 * KILO_BITS]; // message payload.
+               // note that there is a size variation between server and CLT 
- do not
+           // know why this was changed from BUFFZISE, though
+           // no specific problem is seen due to this

        int msgLen, msgType; // message related data
-       int c2sport = 3002;  // default C2S port
+       int c2sport = atoi(PORT2); // default C2S port
        I2Addr sec_addr = NULL; // server address
        int retcode;            // return code
        int one=1;                      // socket option store
@@ -117,9 +120,9 @@
                // ....Fill buffer upto NDTConstants.PREDEFNED_BUFFER_SIZE 
packets
                pkts = 0;
                k = 0;
-		for (i=0; i<(64*KILO_BITS); i++) { //again todo- verify buffer sizes .  
seemed like 8192 a
-                                                                       // 
though, this may not be a problem since the actual
-                                                                       // 
byte tx is timed
+		for (i=0; i<(64*KILO_BITS); i++) { // again buffer sizes differ. Since  
the actual
+                                                                       // 
transmitted byte count is timed, it does'nt appear that it is
+                                                                       // 
causing specific problems.
                        while (!isprint(k&0x7f))
                                k++;
                        buff[i] = (k++ % 0x7f);
@@ -147,10 +150,11 @@

                // Calculate C2S throughput in kbps
                spdout = ((BITS_8 * pkts * lth) / KILO) / t;
+		//log_println(6," ---C->S CLT speed=%0.0f, pkts= %d, lth=%d, time=%d",  
spdout, pkts, lth, t);


                // The client has stopped streaming data, and the server is 
now
-               // expected to send a TEST_MSG message with the throughout it 
calculated.
+               // expected to send a TEST_MSG message with the throughput it 
calculated.
                // So, its time now to receive this throughput (c2sspd).

                msgLen = sizeof(buff);
=======================================
--- /branches/kkumar_code_organize/src/test_mid_clt.c	Sun Oct 23 19:27:44  
2011
+++ /branches/kkumar_code_organize/src/test_mid_clt.c	Tue Oct 25 13:58:59  
2011
@@ -26,7 +26,7 @@
  * @param host hostname of the server
  * @param conn_options connection options
  * @param buf_size TCP send/receive buffer size
- * @param tmpstr2 result obtained from server (containing server ip,
+ * @param testresult_str result obtained from server (containing server ip,
  *                                             client ip, currentMSS, 
WinSCaleSent, WinScaleRcvd)
  * @return  integer
  *     => 0 on success
@@ -45,10 +45,10 @@
  *
  */
 int test_mid_clt(int ctlSocket, char tests, char* host, int conn_options,
-               int buf_size, char* tmpstr2) {
+               int buf_size, char* testresult_str) {
        char buff[BUFFSIZE + 1];
        int msgLen, msgType;
-       int midport = PORT3;
+       int midport = atoi(PORT3);
        I2Addr sec_addr = NULL;
        int retcode, one=1, i, inlth;
        int in2Socket;
@@ -109,7 +109,7 @@
 		// start reading throughput test data from server using the connection  
created above
                printf("Checking for Middleboxes . . . . . . . . . . . . . . . . . 
.  ");
                fflush(stdout);
-               tmpstr2[0] = '\0';
+               testresult_str[0] = '\0';
                i = 0;
                bytes = 0;
                t = secs() + 5.0;  // set timer for 5 seconds, and read for 5 
seconds
@@ -137,13 +137,13 @@
                                break;
                        }
                }
-               // get actual time for which
+               // get actual time for which test was run
                t = secs() - t + 5.0;

                // calculate throughput in Kbps
                spdin = ((BITS_8 * bytes) / KILO) / t;

-               // Test is complete. Now, get throughput results from server.
+		// Test is complete. Now, get results from server (includes CurrentMSS,  
WinScaleSent, WinScaleRcvd..).
                // The results are sent from server in the form of a TEST_MSG 
object
                msgLen = sizeof(buff);
                if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
@@ -154,10 +154,10 @@
                        return 2;
                }

-               strlcat(tmpstr2, buff, 512);// hardcoded size as buffer size 
from main
-
-		memset(buff, 0, 128); // this should work since the throuput results  
from the server should
-               //  ...fit well within 128 chars
+               strlcat(testresult_str, buff, MIDBOX_TEST_RES_SIZE);
+
+		memset(buff, 0, 128); // this should work since the throughput results  
from the server should
+                                                        //  ...fit well 
within 128 chars
                sprintf(buff, "%0.0f", spdin);
                log_println(4, "CWND limited speed = %0.2f kbps", spdin);

=======================================
--- /branches/kkumar_code_organize/src/test_s2c_clt.c	Mon Oct 24 13:08:20  
2011
+++ /branches/kkumar_code_organize/src/test_s2c_clt.c	Tue Oct 25 13:58:59  
2011
@@ -42,7 +42,7 @@
                int buf_size, char* result_srv) {
        char buff[BUFFSIZE + 1];
        int msgLen, msgType;
-       int s2cport = PORT3;
+       int s2cport = atoi(PORT3);
        I2Addr sec_addr = NULL;
        int inlth, retcode, one=1, set_size;
        int inSocket;
=======================================
--- /branches/kkumar_code_organize/src/test_sfw_clt.c	Sun Oct 23 19:27:44  
2011
+++ /branches/kkumar_code_organize/src/test_sfw_clt.c	Tue Oct 25 13:58:59  
2011
@@ -308,7 +308,7 @@
                switch (c2s_result) {
                case SFW_NOFIREWALL:
                        printf(
-                                       "Server '%s' is not behind a 
firewall.",
+                                       "Server '%s' is not behind a 
firewall."
                                        " [Connection to the ephemeral port was 
successful]\n",
                                        host);
                        break;
@@ -326,12 +326,12 @@
                switch (s2c_result) {
                case SFW_NOFIREWALL:
                        printf(
-                                       "Client is not behind a firewall.",
+                                       "Client is not behind a firewall."
                                        " [Connection to the ephemeral port was 
successful]\n");
                        break;
                case SFW_POSSIBLE:
                        printf(
-                                       "Client is probably behind a 
firewall.",
+                                       "Client is probably behind a 
firewall."
                                        " [Connection to the ephemeral port 
failed]\n");
                        break;
                case SFW_UNKNOWN:
=======================================
--- /branches/kkumar_code_organize/src/utils.h  Sun Oct 23 19:27:44 2011
+++ /branches/kkumar_code_organize/src/utils.h  Tue Oct 25 13:58:59 2011
@@ -65,6 +65,8 @@
 //#define BUFFSIZE  8192               // Buffer size

 // middlebox test default MSS
+// Cleaner to move this to clt_tests.h if not for the name  
of "clt_tests.h".
+// ..web100-util.c would need to import this header file.
 #define MIDDLEBOX_PREDEFINED_MSS 8192

 // MAX TCP window size in kilo-bytes
=======================================
--- /branches/kkumar_code_organize/src/web100clt.c      Sun Oct 23 19:27:44 
2011
+++ /branches/kkumar_code_organize/src/web100clt.c      Tue Oct 25 13:58:59 
2011
@@ -20,10 +20,6 @@
 #include "strlutils.h"
 #include "test_results_clt.h"

-#ifndef VIEW_DIFF
-#define VIEW_DIFF 0.1
-#endif
-
 extern int h_errno;

 int Randomize, failed, cancopy;
@@ -67,8 +63,11 @@
  * Print variables from a string containing
  * key-value pairs, where the key is separated from the value by
  * a whitespace and each key-value pair is delimited by a newline.
+ *
+ * This function is not currently used outside this file, and hence
+ * retaining this here.
  * @param tmpstr Char array containing key-value pairs
- * todo: can this go to some clt-utils file? */
+ *  */
 void printVariables(char *tmpstr) {
        int i, j, k;
        char sysvar[128], sysval[128];
@@ -90,9 +89,12 @@
        }
 }

-/** Print information about web 100 variables
+/**
+ * Print information about web 100 variables
  *  from a pre-defined array.
- *  todo :see if this can go to a file called "web100 utils"
+ *
+ * This function is not currently used outside this file, and hence
+ * retaining this here.
  */

 void printWeb100VarInfo() {
@@ -105,30 +107,32 @@
        }
 }

-void testResults(char tests, char *tmpstr, char* host) {
-       int i = 0, Zero = 0;
+/**
+ * Interpret test results based on values received from the S2C, C2S tests  
and
+ *  SFW tests. Print recommendations based on some calculations, or display
+ *  values of settings that have been detected.
+ *
+ * @param tests  test indicator character
+ * @param tmpstr Result string obtained at the end of tests from the server
+ * @param host   server host name string
+ */
+void testResults(char tests, char *testresult_str, char* host) {
+       int i = 0;
+
        char *sysvar, *sysval;
        float j;

+	// If the S2C test was not performed, just interpret the C2S and SFW test  
results
        if (!(tests & TEST_S2C)) {
-               if (tests & TEST_C2S) {
-                       if (c2sspd < (spdout * (1.0 - VIEW_DIFF))) {
-                               printf("Information [C2S]: Packet queuing 
detected: %0.2f%% ",
-                                               100 * (spdout - c2sspd) / 
spdout);
-                               if (sndqueue
-                                               > (0.8 * pkts * lth * (spdout 
- c2sspd) / spdout)) {
-                                       printf("(local buffers)\n");
-                               } else {
-                                       printf("(remote buffers)\n");
-                               }
-                       }
+               if (tests & TEST_C2S) { // Was C2S test performed?
+                       check_C2Spacketqueuing(c2sspd, spdout, sndqueue, 
pkts, lth);
                }

                results_sfw(tests, host);
                return;
        }

-       sysvar = strtok(tmpstr, " ");
+       sysvar = strtok(testresult_str, " ");
        sysval = strtok(NULL, "\n");
        i = atoi(sysval);
        save_int_values(sysvar, i);
@@ -141,114 +145,25 @@
                if (strchr(sysval, '.') == NULL) {
                        i = atoi(sysval);
                        save_int_values(sysvar, i);
-			log_println(6, "Stored %d [%s] in %s", i, sysval, sysvar); //todo  
change level
+                       log_println(7, "Stored %d [%s] in %s", i, sysval, 
sysvar);
                } else {
                        j = atof(sysval);
                        save_dbl_values(sysvar, &j);
-			log_println(6, "Stored %0.2f (%s) in %s", j, sysval, sysvar); //todo  
change level
+                       log_println(7, "Stored %0.2f (%s) in %s", j, sysval, 
sysvar);
                }
        }

-       if (CountRTT > 0) { //todo . Whats ic ountRTT > 0??
+       //CountRTT = 615596;
+       if (CountRTT > 0) { // The number of round trip time samples is finite

 		// Get the link speed as determined during the C2S test. if it was  
performed
                if (tests & TEST_C2S) {
                        mylink = get_linkspeed(c2sData, half_duplex);
-                       /*
-                        //if (c2sData < 3) {
-                        if (c2sData < DATA_RATE_ETHERNET) {
-                        //if (c2sData < 0) {
-                        if (c2sData < DATA_RATE_RTT) {
-                        printf("Server unable to determine bottleneck link 
type.\n");
-                        } else {
-                        printf("Your host is connected to a ");
-                        //if (c2sData == 1) {
-                        if (c2sData == DATA_RATE_DIAL_UP) {
-                        printf("Dial-up Modem\n");
-                        mylink = .064;
-                        } else {
-                        printf("Cable/DSL modem\n");
-                        mylink = 2;
-                        }
-                        }
-                        } else {
-                        printf("The slowest link in the end-to-end path is a 
");
-                        //if (c2sData == 3) {
-                        if (c2sData == DATA_RATE_ETHERNET) {
-                        printf("10 Mbps Ethernet or WiFi 11b subnet\n");
-                        mylink = 10;
-                        //} else if (c2sData == 4) {
-                        } else if (c2sData == DATA_RATE_T3) {
-                        printf("45 Mbps T3/DS3 or WiFi 11 a/g  subnet\n");
-                        mylink = 45;
-                        //} else if (c2sData == 5) {
-                        } else if (c2sData == DATA_RATE_FAST_ETHERNET) {
-                        printf("100 Mbps ");
-                        mylink = 100;
-                        if (half_duplex == 0) {
-                        printf("Full duplex Fast Ethernet subnet\n");
-                        } else {
-                        printf("Half duplex Fast Ethernet subnet\n");
-                        }
-                        //} else if (c2sData == 6) {
-                        } else if (c2sData == DATA_RATE_OC_12) {
-                        printf("a 622 Mbps OC-12 subnet\n");
-                        mylink = 622;
-                        //} else if (c2sData == 7) {
-                        } else if (c2sData == DATA_RATE_GIGABIT_ETHERNET) {
-                        printf("1.0 Gbps Gigabit Ethernet subnet\n");
-                        mylink = 1000;
-                        //} else if (c2sData == 8) {
-                        } else if (c2sData == DATA_RATE_OC_48) {
-                        printf("2.4 Gbps OC-48 subnet\n");
-                        mylink = 2400;
-                        //} else if (c2sData == 9) {
-                        } else if (c2sData == DATA_RATE_10G_ETHERNET) {
-                        printf("10 Gbps 10 Gigabit Ethernet/OC-192 
subnet\n");
-                        mylink = 10000;
-                        }
-                        }*/
                }

-               /*
-                switch(mismatch) {
-                case 1 : printf("Warning: Old Duplex-Mismatch condition 
detected.\n");
-                break;
-
-		 case 2 : printf("Alarm: Duplex Mismatch condition detected. Switch=Full  
and Host=Half\n");
-                break;
-		 case 4 : printf("Alarm: Possible Duplex Mismatch condition detected.  
Switch=Full and Host=Half\n");
-                break;
-
-		 case 3 : printf("Alarm: Duplex Mismatch condition detected. Switch=Half  
and Host=Full\n");
-                break;
-		 case 5 : printf("Alarm: Possible Duplex Mismatch condition detected.  
Switch=Half and Host=Full\n");
-                break;
-		 case 7 : printf("Warning: Possible Duplex Mismatch condition detected.  
Switch=Half and Host=Full\n");
-                break;
-                }
-                */
                print_results_mismatchcheck(mismatch);

                if (mismatch == 0) {
-                       /*
-                        if (bad_cable == 1) {
-                        printf("Alarm: Excessive errors, check network 
cable(s).\n");
-                        }
-                        if (congestion == 1) {
-                        printf("Information: Other network traffic is congesting 
the link\n");
-                        }
-
-			 log_print(3, "Is larger buffer recommended?  rwin*2/rttsec (%0.4f) <  
mylink (%0.4f) ", ((rwin*2)/rttsec), mylink);
-			 log_println(3, "AND j (%0.4f) > MaxRwinRcvd (%d)", (float)((mylink *  
avgrtt)*1000)/8, MaxRwinRcvd);
-                        if (((rwin*2)/rttsec) < mylink) {
-                        j = (float)((mylink * avgrtt)*1000) / 8;
-                        if ((int)j > MaxRwinRcvd) {
-                        printf("Information: The receive buffer should be %0.0f 
", j/1024);
-                        printf("kbytes to maximize throughput\n");
-                        }
-                        }
-                        */
                        check_congestion(congestion);
                        check_badcable(bad_cable);
                        print_recommend_buffersize(rwin, rttsec, avgrtt, 
mylink,
@@ -256,27 +171,10 @@
                }

                if (tests & TEST_C2S) {
-                       if (c2sspd < (spdout * (1.0 - VIEW_DIFF))) {
-                               printf("Information [C2S]: Packet queuing 
detected: %0.2f%% ",
-                                               100 * (spdout - c2sspd) / 
spdout);
-                               if (sndqueue
-                                               > (0.8 * pkts * lth * (spdout 
- c2sspd) / spdout)) {
-                                       printf("(local buffers)\n");
-                               } else {
-                                       printf("(remote buffers)\n");
-                               }
-                       }
+                       check_C2Spacketqueuing(c2sspd,spdout,sndqueue, pkts, 
lth);
                }
                if (tests & TEST_S2C) {
-                       if (spdin < (s2cspd * (1.0 - VIEW_DIFF))) {
-                               printf("Information [S2C]: Packet queuing 
detected: %0.2f%% ",
-                                               100 * (s2cspd - spdin) / 
s2cspd);
-                               if (ssndqueue > (0.8 * sbytes * (s2cspd - 
spdin) / s2cspd)) {
-                                       printf("(local buffers)\n");
-                               } else {
-                                       printf("(remote buffers)\n");
-                               }
-                       }
+                       check_S2Cpacketqueuing(s2cspd,spdin,ssndqueue, 
sbytes);
                }

                results_sfw(tests, host);
@@ -288,124 +186,43 @@
                                        avgrtt);

                        printf("the Packet size = %d Bytes; and \n", 
CurrentMSS);
-                       if (PktsRetrans > 0) {
-                               printf("There were %d packets retransmitted", 
PktsRetrans);
-                               printf(", %d duplicate acks received", 
DupAcksIn);
-                               printf(", and %d SACK blocks received\n", 
SACKsRcvd);
-                               if (order > 0)
-                                       printf(
-                                                       "Packets arrived 
out-of-order %0.2f%% of the time.\n",
-                                                       order * 100);
-                               if (Timeouts > 0)
-                                       printf(
-                                                       "The connection stalled %d 
times due to packet loss.\n",
-                                                       Timeouts);
-                               if (waitsec > 0)
-                                       printf(
-                                                       "The connection was idle 
%0.2f seconds (%0.2f%%) of the time.\n",
-                                                       waitsec, (100 * 
waitsec / timesec));
-                       } else if (DupAcksIn > 0) {
-                               printf("No packet loss - ");
-                               if (order > 0)
-                                       printf(
-                                                       "but packets arrived 
out-of-order %0.2f%% of the time.\n",
-                                                       order * 100);
-                               else
-                                       printf("\n");
-                       } else {
-                               printf("No packet loss was observed.\n");
-                       }
-
-                       if (rwintime > .015) {
-                               printf(
-                                               "This connection is receiver 
limited %0.2f%% of the time.\n",
-                                               rwintime * 100);
-                               if ((2 * (rwin / rttsec)) < mylink)
-                                       printf(
-							"  Increasing the current receive buffer (%0.2f KB) will improve  
performance\n",
-                                                       (float) MaxRwinRcvd / 
1024);
-                       }
-                       if (sendtime > .015) {
-                               printf(
-                                               "This connection is sender limited 
%0.2f%% of the time.\n",
-                                               sendtime * 100);
-                               if ((2 * (swin / rttsec)) < mylink)
-                                       printf(
-							"  Increasing the current send buffer (%0.2f KB) will improve  
performance\n",
-                                                       (float) Sndbuf / 
1024);
-                       }
-                       if (cwndtime > .005) {
-                               printf(
-                                               "This connection is network 
limited %0.2f%% of the time.\n",
-                                               cwndtime * 100);
-                       }
-                       if ((spd < 4) && (loss > .01)) {
-                               printf(
-                                               "Excessive packet loss is 
impacting your performance, check the ");
-                               printf(
-                                               "auto-negotiate function on your 
local PC and network switch\n");
-                       }
-                       printf(
-					"\n    Web100 reports TCP negotiated the optional Performance  
Settings to: \n");
-                       printf("RFC 2018 Selective Acknowledgment: ");
-                       if (SACKEnabled == Zero)
-                               printf("OFF\n");
-                       else
-                               printf("ON\n");
-
-                       printf("RFC 896 Nagle Algorithm: ");
-                       if (NagleEnabled == Zero)
-                               printf("OFF\n");
-                       else
-                               printf("ON\n");
-
-                       printf("RFC 3168 Explicit Congestion Notification: ");
-                       if (ECNEnabled == Zero)
-                               printf("OFF\n");
-                       else
-                               printf("ON\n");
-
-                       printf("RFC 1323 Time Stamping: ");
-                       if (TimestampsEnabled == 0)
-                               printf("OFF\n");
-                       else
-                               printf("ON\n");
-
-                       printf("RFC 1323 Window Scaling: ");
-                       if (MaxRwinRcvd < 65535)
-                               WinScaleRcvd = 0;
-
-                       if ((WinScaleRcvd == 0) || (WinScaleRcvd > 20))
-                               printf("OFF\n");
-                       else
-                               printf("ON; Scaling Factors - Server=%d, 
Client=%d\n",
-                                               WinScaleRcvd, WinScaleSent);
-
-                       if ((RcvWinScale == 0) && (Sndbuf > 65535))
-                               Sndbuf = 65535;
-
-                       printf("The theoretical network limit is %0.2f 
Mbps\n", estimate);
-
-                       printf(
-					"The NDT server has a %0.0f KByte buffer which limits the throughput  
to %0.2f Mbps\n",
-                                       (float) Sndbuf / 1024, (float) swin / 
rttsec);
-
-                       printf(
-					"Your PC/Workstation has a %0.0f KByte buffer which limits the  
throughput to %0.2f Mbps\n",
-                                       (float) MaxRwinRcvd / 1024, (float) 
rwin / rttsec);
-
-                       printf(
-					"The network based flow control limits the throughput to %0.2f  
Mbps\n",
-                                       (float) cwin / rttsec);
-
-                       if (tests & TEST_C2S) {
-                               printf(
-						"\nClient Data reports link is '%3d', Client Acks report link  
is '%3d'\n",
-                                               c2sData, c2sAck);
-                       }
-                       printf(
-					"Server Data reports link is '%3d', Server Acks report link  
is '%3d'\n",
-                                       s2cData, s2cAck);
+
+                       // print packet loss statistics
+                       print_packetloss_statistics (PktsRetrans, DupAcksIn, 
SACKsRcvd,
+                               order,Timeouts,waitsec, timesec);
+
+			// print details of whether connection was send/receive/congestion  
limited
+			print_limitedtime_ratio( rwintime, rwin, sendtime, swin,  cwndtime,   
rttsec,
+                                        mylink,  Sndbuf, MaxRwinRcvd);
+
+                       // check to see if excessive packet loss was reported
+                       print_packetloss_excess(spd, loss);
+
+			// Now print details of optional Performance settings values like the  
following list:
+                       printf(
+					"\n    Web100 reports TCP negotiated the optional Performance  
Settings to: \n");
+
+                       // ..Selective ack options
+                       print_SAck_RFC2018(SACKEnabled);
+
+                       // ..Nagle algo details
+                       print_Nagle_RFC896(NagleEnabled);
+
+                       // ..Explicit Congestion Notification
+                       print_congestion_RFC3168(ECNEnabled);
+
+                       // ..RFC 1323 Time Stamping
+                       print_timestamping_RFC1323(TimestampsEnabled);
+
+                       // ..RFC 1323 Window Scaling
+                       print_windowscaling(MaxRwinRcvd,WinScaleRcvd, 
WinScaleSent);
+
+                       // ..throughput limiting factors details
+			print_throughputlimits(MaxRwinRcvd, RcvWinScale, &Sndbuf, swin, rwin,  
cwin, rttsec,estimate);
+
+                       // client and server's views of link speed
+                       print_linkspeed_dataacks((tests & TEST_C2S), c2sData,
+                                       c2sAck,s2cData, s2cAck) ;
                }
        } else {
                printf(
@@ -416,28 +233,31 @@
        }
 }

-/* this routine decodes the middlebox test results.  The data is returned
+/**
+ * This routine decodes the middlebox test results.  The data is returned
  * from the server in a specific order.  This routine pulls the string  
apart
  * and puts the values into the proper variable.  It then compares the  
values
  * to known values and writes out the specific results.
  *
- * server data is first
+ * Server data is first.
  * order is Server IP; Client IP; CurrentMSS; WinScaleRcvd; WinScaleSent;
  * Client then adds
  * Server IP; Client IP.
+ * @param midresult_str  String containing test results
+ * @param local_addr Client IP address
+ * @param peer_addr  Server IP address
  */

-void middleboxResults(char *tmpstr, I2Addr local_addr, I2Addr peer_addr) {
+void middleboxResults(char *midresult_str, I2Addr local_addr, I2Addr  
peer_addr) {
        char ssip[64], scip[64], *str;
        char csip[64], ccip[64];
        int mss;
        size_t tmpLen;

-       str = strtok(tmpstr, ";");
-       //strcpy(ssip, str);
+       str = strtok(midresult_str, ";");
        strlcpy(ssip, str, sizeof(ssip));
        str = strtok(NULL, ";");
-       //strcpy(scip, str);
+
        strlcpy(scip, str, sizeof(scip));

        str = strtok(NULL, ";");
@@ -454,32 +274,20 @@
        tmpLen = 63;
        I2AddrNodeName(peer_addr, csip, &tmpLen);

-       if (TimestampsEnabled == 1)
-               mss += 12;
-       if (mss == 1456)
-               printf("Packet size is preserved End-to-End\n");
-       else
-               printf(
-				"Information: Network Middlebox is modifying MSS variable (changed  
to %d)\n",
-                               mss);
-
-       if (strcmp(ssip, csip) == 0)
-               printf("Server IP addresses are preserved End-to-End\n");
-       else {
-               printf("Information: Network Address Translation (NAT) box is 
");
-               printf("modifying the Server's IP address\n");
-               printf("\tServer says [%s] but Client says [ %s]\n", ssip, 
csip);
-       }
-
-       if (strcmp(scip, ccip) == 0)
-               printf("Client IP addresses are preserved End-to-End\n");
-       else {
-               printf("Information: Network Address Translation (NAT) box is 
");
-               printf("modifying the Client's IP address\n");
-               printf("\tServer says [%s] but Client says [ %s]\n", scip, 
ccip);
-       }
+       // Check if MSS modification is happening
+       check_MSS_modification(TimestampsEnabled, &mss);
+
+       // detect Network Address translation box
+       check_NAT(ssip, csip, scip, ccip);
+
 }

+/**
+ * Save integer values for web100 variables obtained
+ *     into local variables.
+ * @param sysvar Variable's name string
+ * @param sysval value of this variable
+ */
 void save_int_values(char *sysvar, int sysval) {
        /*  Values saved for interpretation:
         *      SumRTT
@@ -604,6 +412,12 @@
                peaks = sysval;
 }

+/**
+ * Save float values for web100 variables obtained
+ *     into local variables.
+ * @param sysvar Variable's name
+ * @param sysval variable's value
+ */
 void save_dbl_values(char *sysvar, float *sysval) {
        if (strcmp(sysvar, "bw:") == 0)
                estimate = *sysval;
@@ -637,20 +451,33 @@
                aspd = *sysval;
 }

+/**
+ * Main function of web command line tool
+ * @param argc Number of command line arguments
+ * @param argv  Command line arguments
+ * @return > 0 if successful, < 0 if not
+ */
 int main(int argc, char *argv[]) {
-       int c, swait;
-       char tmpstr2[512], tmpstr[16384], varstr[16384];
+       int useroption;                         // user options char
+       int swait;                                      // server wait status
+       char mid_resultstr[MIDBOX_TEST_RES_SIZE];       // MID test results
+       char resultstr[2*BUFFSIZE];             // S2C test results, 16384 = 
2 * BUFFSIZE
+	char varstr[2*BUFFSIZE]; 		// temporary storage for S2C test results ,  
16384 = 2 * BUFFSIZE
        unsigned char tests = TEST_MID | TEST_C2S | TEST_S2C | TEST_SFW
-                       | TEST_STATUS | TEST_META;
-       int ctlSocket;
-       int ctlport = 3001;
-       int ret, xwait;
-       char buff[8192];
-       char* strtokbuf;
-       char *host = NULL;
-       int buf_size = 0;
-       int msgLen, msgType;
-       int conn_options = 0, debug = 0, testId;
+			| TEST_STATUS | TEST_META; // which tests have been selectedto be  
performed?
+       int ctlSocket;                          // socket fd
+       int ctlport = atoi(PORT);       // default port number
+       int retcode;                            // return code from protocol 
operations, mostly
+       int xwait;                                      // wait flag
+       char buff[BUFFSIZE];            // buffer used to store protocol 
message payload
+       char* strtokbuf;                        // buffer to store string 
tokens
+       char *host = NULL;                      // server name to connect to
+       int buf_size = 0;                       // TCP send/receive window 
size received from user
+       int msgLen, msgType;            // protocol message related variables
+       int conn_options = 0;           // connection options received from 
user
+       int debug = 0;                          // debug flag
+       int testId;                                     // test ID received 
from server
+       // addresses..
        I2Addr server_addr = NULL;
        I2Addr local_addr = NULL, remote_addr = NULL;
        char* ptr;
@@ -660,10 +487,10 @@
 #else
 #define GETOPT_LONG_INET6(x) x
 #endif
-
-       while ((c = getopt_long(argc, argv, GETOPT_LONG_INET6("n:p:dhlvb:"),
+       // Read and record various optional values used for the tests/process
+	while ((useroption = getopt_long(argc, argv,  
GETOPT_LONG_INET6("n:p:dhlvb:"),
                        long_options, 0)) != -1) {
-               switch (c) {
+               switch (useroption) {
                case '4':
                        conn_options |= OPT_IPV4_ONLY;
                        break;
@@ -722,14 +549,17 @@

        failed = 0;

+       // Check if user options do not include any test!
        if (!(tests & (TEST_MID | TEST_C2S | TEST_S2C | TEST_SFW))) {
                short_usage(argv[0], "Cannot perform empty test suites");
        }

+       // A server is needed to run the tests against
        if (host == NULL) {
                short_usage(argv[0], "Name of the server is required");
        }

+       // Check for initial configuration and performance problems
        printf(
 			"Testing network path for configuration and performance problems   
--  ");
        fflush(stdout);
@@ -740,12 +570,13 @@
        }
        I2AddrSetPort(server_addr, ctlport);

-	if ((ret = CreateConnectSocket(&ctlSocket, NULL, server_addr,  
conn_options,
+	if ((retcode = CreateConnectSocket(&ctlSocket, NULL, server_addr,  
conn_options,
                        0))) {
                printf("Connect() for control socket failed\n");
                exit(-4);
        }

+       // check and print Address family being used
        if (I2AddrSAddr(server_addr, 0)->sa_family == AF_INET) {
                printf("Using IPv4 address\n");
        } else {
@@ -779,7 +610,7 @@

        /* The beginning of the protocol */

-       /* write our test suite request */
+       /* write our test suite request by sending a login message */
        send_msg(ctlSocket, MSG_LOGIN, &tests, 1);
        /* read the specially crafted data that kicks off the old clients */
        if (readn(ctlSocket, buff, 13) != 13) {
@@ -788,6 +619,11 @@
                                host);
                exit(0);
        }
+
+	// The server now sends a SRV_QUEUE message to indicate whether/not to  
wait
+       // SRV_QUEUE messages are only sent to queued clients with a message
+	// body that indicates one of a few statuses, as will be handled  
individually
+       // below.

        swait = 0;
        for (;;) {
@@ -797,7 +633,7 @@
                        exit(1);
                }
                if (check_msg_type("Logging to server", SRV_QUEUE, msgType, 
buff,
-                               msgLen)) {
+                               msgLen)) { // Any other type of message at 
this stage is incorrect
                        exit(2);
                }
                if (msgLen <= 0) {
@@ -809,39 +645,51 @@
                        log_println(0, "Invalid queue indicator");
                        exit(4);
                }
-               if (xwait == 0) /* signal from ver 3.0.x NDT servers */
+               // SRV_QUEUE message received indicating "ready to start 
tests" .
+               // ...proceed to running tests
+		if (xwait == SRV_QUEUE_TEST_STARTS_NOW) /* signal from ver 3.0.x NDT  
servers */
                        break;
-               if (xwait == 9977) {
+
+               if (xwait == SRV_QUEUE_SERVER_FAULT) {
                        fprintf(
                                        stderr,
-					"Server Fault: Test terminated for unknown reason, plase try again  
later.\n");
+					"Server Fault: Test terminated for unknown reason, please try again  
later.\n");
                        exit(0);
                }
-               if (xwait == 9988) {
-                       if (swait == 0)
+               if (xwait == SRV_QUEUE_SERVER_BUSY) {
+                       if (swait == 0) {
+                                // First message from server, indicating 
server is busy. Quit
                                fprintf(
                                                stderr,
 						"Server Busy: Too many clients waiting in queue, plase try again  
later.\n");
-                       else
+                       }
+                       else { // Server fault, quit
                                fprintf(
                                                stderr,
 						"Server Fault: Test terminated for unknown reason, plase try again  
later.\n");
+                       }
                        exit(0);
                }
-               if (xwait == 9999) {
+               // server busy, wait 60 s for previous test to finish
+               if (xwait == SRV_QUEUE_SERVER_BUSY_60s) {
                        fprintf(
                                        stderr,
 					"Server Busy: Please wait 60 seconds for the current test to  
finish.\n");
                        exit(0);
                }
-		if (xwait == 9990) { /* Signal from the server to see if the client is  
still alive */
+               // Signal from the server to see if the client is still alive
+               if (xwait == SRV_QUEUE_HEARTBEAT) {
                        send_msg(ctlSocket, MSG_WAITING, &tests, 1);
                        continue;
                }

-		/* Each test should take less than 30 seconds, so tell them 45 sec *  
number of
-                * tests in the queue.
-                */
+
+               /* Each test should take less than 30 s. So convey 45 sec *
+                 number of tests-suites waiting in the queue. Note that 
server sends a
+                 number equal to the number of clients ==
+                number of minutes to wait before starting tests. In other 
words,
+                wait = num of minutes to wait = number of queued clients */
+
                xwait = (xwait * 45);
                log_print(0,
                                "Another client is currently begin served, your 
test will ");
@@ -854,6 +702,10 @@
         */
        alarm(90);

+       // Tests can be started. Read server response again.
+       // The server must send MSG_LOGIN  message to verify version.
+       // Any other type of message is unexpected at this point.
+
        msgLen = sizeof(buff);
        if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
                log_println(0, "Protocol error - expected version message!");
@@ -867,8 +719,11 @@
                log_println(0, "Improper message");
                exit(3);
        }
+
+       // Version compatibility between server-client must be verified
+
        buff[msgLen] = 0;
-       if (buff[0] != 'v') {
+       if (buff[0] != 'v') { // payload does'nt start with a version 
indicator
                log_println(0, "Incompatible version number");
                exit(4);
        }
@@ -878,6 +733,9 @@
                                &buff[1]);
        }

+       // Server must send a message to negotiate the test suite, and this is
+    // a MSG_LOGIN type of message which indicates the same set of tests as
+    // requested by the client earlier
        msgLen = sizeof(buff);
        if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
                log_println(0, "Protocol error - expected test suite 
message!");
@@ -891,6 +749,8 @@
                log_println(0, "Improper message");
                exit(3);
        }
+
+       // get ids of tests to be run now
        buff[msgLen] = 0;
        log_println(5, "Received tests sequence: '%s'", buff);
        if ((strtokbuf = malloc(1024)) == NULL) {
@@ -899,6 +759,7 @@
        }
        ptr = strtok_r(buff, " ", &strtokbuf);

+       // Run all tests requested, based on the ID.
        while (ptr) {
                if (check_int(ptr, &testId)) {
                        log_println(0, "Invalid test ID");
@@ -907,7 +768,7 @@
                switch (testId) {
                case TEST_MID:
                        if (test_mid_clt(ctlSocket, tests, host, 
conn_options, buf_size,
-                                       tmpstr2)) {
+                                       mid_resultstr)) {
                                log_println(0, "Middlebox test FAILED!");
                                tests &= (~TEST_MID);
                        }
@@ -920,7 +781,7 @@
                        break;
                case TEST_S2C:
                        if (test_s2c_clt(ctlSocket, tests, host, 
conn_options, buf_size,
-                                       tmpstr)) {
+                                       resultstr)) {
                                log_println(0, "S2C throughput test FAILED!");
                                tests &= (~TEST_S2C);
                        }
@@ -944,7 +805,7 @@
                ptr = strtok_r(NULL, " ", &strtokbuf);
        }

-       /* get the final results from server
+       /* get the final results from server.
         *
         * The results are encapsulated by the MSG_RESULTS messages. The last
         * message is MSG_LOGOUT.
@@ -952,7 +813,7 @@
        for (;;) {
                msgLen = sizeof(buff);
                memset(buff, 0, msgLen); // reset buff and msgLen
-               if (ret = (recv_msg(ctlSocket, &msgType, buff, &msgLen))) {
+               if (retcode = (recv_msg(ctlSocket, &msgType, buff, &msgLen))) 
{
                        if (errno == ECONNRESET)
                                log_println(0,
                                                "Connection closed by server, No 
test performed.");
@@ -970,19 +831,25 @@
                                msgLen)) {
                        exit(2);
                }
-               strlcat(tmpstr, buff, sizeof(tmpstr));
-               log_println(6, "tmpstr = '%s'", tmpstr);
+
+               strlcat(resultstr, buff, sizeof(resultstr));
+               log_println(6, "resultstr = '%s'", resultstr);
        }

        local_addr = I2AddrByLocalSockFD(get_errhandle(), ctlSocket, False);
        remote_addr = I2AddrBySockFD(get_errhandle(), ctlSocket, False);
        I2AddrFree(server_addr);
-       //strcpy(varstr, tmpstr);
-       strlcpy(varstr, tmpstr, sizeof(varstr));
-       testResults(tests, tmpstr, host);
+
+       strlcpy(varstr, resultstr, sizeof(varstr));
+       // print test results
+       testResults(tests, resultstr, host);
+
+       // print middlebox test results
        if (tests & TEST_MID) {
-               middleboxResults(tmpstr2, local_addr, remote_addr);
-       }
+               middleboxResults(mid_resultstr, local_addr, remote_addr);
+       }
+
+       // print extra information collected from web100 variables
        if ((tests & TEST_S2C) && (msglvl > 1))
                printVariables(varstr);
        return 0;