NDT-DEV email list created

Revision: 736
Author:   

Date:     Mon Oct 24 13:08:20 2011
Log:      S->C CLT side code inline comments and code factoring
http://code.google.com/p/ndt/source/detail?r=736

Modified:
 /branches/kkumar_code_organize/src/test_s2c_clt.c

=======================================
--- /branches/kkumar_code_organize/src/test_s2c_clt.c	Mon Oct 17 06:43:25  
2011
+++ /branches/kkumar_code_organize/src/test_s2c_clt.c	Mon Oct 24 13:08:20  
2011
@@ -1,4 +1,4 @@
-/*
+/**
  * This file contains the functions needed to handle S2C throughput
  * test (client part).
  *
@@ -19,12 +19,32 @@
 int ssndqueue, sbytes;
 double spdin, s2cspd;

+/**
+ * S2C throughput test to measure network bandwidth
+ * from server to client.
+ * @param ctlSocket    Socket on which messages are received from the server
+ * @param tests        Character indicator for test to be run
+ * @param host          Server name string
+ * @param conn_options 	Options to use while connecting to server(for ex,  
IPV4)
+ * @param buf_size     TCP send/receive buffer size
+ * @param result_srv		result obtained from server (containing values of  
web100 variables)
+ * @return integer > 0 if successful, < 0 in case of error
+ *             Return codes:
+ *             1: Error receiving protocol message
+ *             2: Unexpected protocol message (type) received
+ *             3: Improper message payload
+ *             4: Incorrect message data received
+ *             -3: Unable to resolve server address
+ *             -15: Cannot connect to server
+ */
+
 int test_s2c_clt(int ctlSocket, char tests, char* host, int conn_options,
-               int buf_size, char* tmpstr) {
-       char buff[BUFFSIZE + 1];int msgLen, msgType;
-       int s2cport = 3003;
+               int buf_size, char* result_srv) {
+       char buff[BUFFSIZE + 1];
+       int msgLen, msgType;
+       int s2cport = PORT3;
        I2Addr sec_addr = NULL;
-       int inlth, ret, one=1, set_size;
+       int inlth, retcode, one=1, set_size;
        int inSocket;
        socklen_t optlen;
        uint32_t bytes;
@@ -34,15 +54,19 @@
        char* ptr;

        if (tests & TEST_S2C) {
+        // First message expected from the server is a TEST_PREPARE. Any  
other message
+               // ...type is unexpected at this point.
                log_println(1, " <-- S2C throughput test -->");
                msgLen = sizeof(buff);
                if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
                        log_println(0, "Protocol error - missed prepare 
message!");
                        return 1;
                }
-		if (check_msg_type("S2C throughput test", TEST_PREPARE, msgType, buff,  
msgLen)) {
+               if (check_msg_type(S2C_TEST_LOG, TEST_PREPARE, msgType, buff, 
msgLen)) {
                        return 2;
                }
+		// This TEST_PREPARE message is expected to have the port number as  
message body.
+               // Check if this is a valid integral port.
                if (msgLen <= 0) {
                        log_println(0, "Improper message");
                        return 3;
@@ -61,13 +85,15 @@
                optlen = sizeof(set_size);
                getsockopt(ctlSocket, SOL_SOCKET, SO_SNDBUF, &set_size, 
&optlen);

+               // get "address details" of the server using the host name
                if ((sec_addr = I2AddrByNode(get_errhandle(), host)) == NULL) 
{
                        log_println(0, "Unable to resolve server address: 
%s", strerror(errno));
                        return -3;
                }
-               I2AddrSetPort(sec_addr, s2cport);
-
-		if ((ret = CreateConnectSocket(&inSocket, NULL, sec_addr, conn_options,  
buf_size))) {
+		I2AddrSetPort(sec_addr, s2cport); //set port to value obtained from  
server
+
+               // Connect to the server; set socket options
+		if ((retcode = CreateConnectSocket(&inSocket, NULL, sec_addr,  
conn_options, buf_size))) {
 			log_println(0, "Connect() for Server to Client failed",  
strerror(errno));
                        return -15;
                }
@@ -84,31 +110,38 @@
                 * queued up on the server.
                 */

+               // Expect a TEST_START message from server now. Any other 
message
+               // type is an error
                msgLen = sizeof(buff);
                if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
                        log_println(0, "Protocol error - missed start 
message!");
                        return 1;
                }
-		if (check_msg_type("S2C throughput test", TEST_START, msgType, buff,  
msgLen)) {
+               if (check_msg_type(S2C_TEST_LOG, TEST_START, msgType, buff, 
msgLen)) {
                        return 2;
                }
+
+               // server performs the S->C throughput test now. Get data 
sent by server.

                printf("running 10s inbound test (server to client) . . . . . . 
");
                fflush(stdout);

+               // Set socket timeout to 15 seconds
                bytes = 0;
                t = secs() + 15.0;
                sel_tv.tv_sec = 15;
                sel_tv.tv_usec = 5;
                FD_ZERO(&rfd);
                FD_SET(inSocket, &rfd);
+               // Read data sent by server as soon as it is available. Stop 
listening if
+               // ...timeout has been exceeded.
                for (;;) {
-                       ret = select(inSocket+1, &rfd, NULL, NULL, &sel_tv);
+                       retcode = select(inSocket+1, &rfd, NULL, NULL, 
&sel_tv);
                        if (secs() > t) {
                                log_println(5, "Receive test running long, break 
out of read loop");
                                break;
                        }
-                       if (ret > 0) {
+                       if (retcode > 0) {
                                inlth = read(inSocket, buff, sizeof(buff));
                                if (inlth == 0)
                                break;
@@ -120,18 +153,22 @@
                        }
                        break;
                }
+
+		// get actual time for which data was received, and calculate throughput  
based on it.
                t = secs() - t + 15.0;
-               spdin = ((8.0 * bytes) / 1000) / t;
-
-               /* receive the s2cspd from the server */
+               spdin = ((BITS_8 * bytes) / KILO) / t; //kbps
+
+		// Server sends calculated throughput value, unsent data amount in the  
socket queue
+               // and overall number of sent bytes in a TEST_MSG
                msgLen = sizeof(buff);
                if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
                        log_println(0, "Protocol error - missed text 
message!");
                        return 1;
                }
-		if (check_msg_type("S2C throughput test", TEST_MSG, msgType, buff,  
msgLen)) {
-                       return 2;
-               }
+               if (check_msg_type(S2C_TEST_LOG, TEST_MSG, msgType, buff, 
msgLen)) {
+                       return 2; // no other message type expected
+               }
+               // Is message of valid length, and does it have all the data 
expected?
                if (msgLen <= 0) {
                        log_println(0, "Improper message");
                        return 3;
@@ -142,20 +179,21 @@
                        log_println(0, "S2C: Improper message");
                        return 4;
                }
-               s2cspd = atoi(ptr);
+               s2cspd = atoi(ptr);  // get S->C throughput first
                ptr = strtok(NULL, " ");
                if (ptr == NULL) {
                        log_println(0, "S2C: Improper message");
                        return 4;
                }
-               ssndqueue = atoi(ptr);
+               ssndqueue = atoi(ptr); // get amount of unsent data in queue
                ptr = strtok(NULL, " ");
                if (ptr == NULL) {
                        log_println(0, "S2C: Improper message");
                        return 4;
                }
-               sbytes = atoi(ptr);
-
+               sbytes = atoi(ptr);     // finally get total-sent-byte-count
+log_println(0,"S->C received throughput: %f",s2cspd);
+               // log results in a convenient units format
                if (spdin < 1000)
                printf("%0.2f kb/s\n", spdin);
                else
@@ -163,27 +201,36 @@

                I2AddrFree(sec_addr);

+               // send TEST_MSG to server with the client-calculated 
throughput
                sprintf(buff, "%0.0f", spdin);
                send_msg(ctlSocket, TEST_MSG, buff, strlen(buff));

-               /* get web100 variables from server */
-               tmpstr[0] = '\0';
+               // client now expected to receive web100 variables collected 
by server
+
+               result_srv[0] = '\0';
                for (;;) {
                        msgLen = sizeof(buff);
+                       memset(buff,0,msgLen); // reset buff and msgLen
+
+                       // get web100 variables
                        if (recv_msg(ctlSocket, &msgType, buff, &msgLen)) {
                                log_println(0, "Protocol error - missed 
text/finalize message!");
                                return 1;
                        }
+
+			// TEST_FINALIZE msg from server indicates end of web100 var  
transmission
                        if (msgType == TEST_FINALIZE) {
                                break;
                        }
-			if (check_msg_type("S2C throughput test", TEST_MSG, msgType, buff,  
msgLen)) {
+
+                       // if neither TEST_FINALIZE, nor TEST_MSG, signal 
error!
+                       if (check_msg_type(S2C_TEST_LOG, TEST_MSG, msgType, 
buff, msgLen)) {
                                return 2;
                        }
-                       //strncat(tmpstr, buff, msgLen);
-                       strlcat(tmpstr, buff, 512);//todo hardcoded size of 
array for now
-               }
-               log_println(6, "tmpstr = '%s'", tmpstr);
+
+			strlcat(result_srv, buff, 2 * BUFFSIZE); // hardcoded size of array  
from main tests
+               }
+               log_println(6, "result_srv = '%s', of len %d", result_srv, 
msgLen);
                log_println(1, " <------------------------->");
        }