a2/1cases.tex

   1 \subsection{Preflight checklist}
   2 Before actual certification is commenced we perform a manual test using a
   3 checklist.
   4 If any of the checks fail we immediately reject the product.
   5 The checklist is given in the table below. All commands in \texttt{monospace}
   6 are to be run in a terminal. Commands prefixed with a \texttt{\#} should be run
   7 with root permissions. Commands prefixed with a \texttt{\$} should be run with
   8 user permissions.
   9
  10 \begin{longtable}{|l|rp{.8\linewidth}|}
  11         \hline
  12         Check 1 & \multicolumn{2}{l|}{Get the SUT in a workable state.}\\
  13         \hline
  14         \multirow{3}{*}{Course of action}
  15                 & 1. & Import the VirtualBox image into VirtualBox.\\
  16                 & 2. & Boot the vm.\\
  17                 & 3. & Verify the SUT booted successfully and the network modules are
  18                 loaded.\\
  19         \hline
  20         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  21         \hline\hline
  22         Check 2 & \multicolumn{2}{l|}{Verify the SUT is complete.}\\
  23         \hline
  24         \multirow{5}{*}{Course of action}
  25                 & 1. & Boot the SUT as in \emph{Check 1}.\\
  26                 & 2. & Verify the loopback device exists by running
  27                          \texttt{\$ ifconfig}.\\
  28                 & 3. & Verify the \emph{echo-server} is present on the system by running
  29                         \texttt{\$ file code/server/Main.java}\\
  30                 & 4. & Verify \emph{Scapy} is present on the system by running
  31                         \texttt{\$ scapy}.\\
  32                 & 5. & Verify all scripts used for testing are present on the system.\\
  33         \hline
  34         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  35         \hline\hline
  36         Check 3 & \multicolumn{2}{l|}{Initialize the testing environment..}\\
  37         \hline
  38         \multirow{6}{*}{Course of action}
  39                 & 1. & Boot the SUT as in \emph{Check 1}.\\
  40                 & 2. & Setup iptables by executing
  41                         \texttt{\# code/iptables.sh}~\footnote{The IPTables script ensures
  42                         that the OS does not drop packets due to an the unknown source.}\\
  43                 & 3. & Navigate to the working directory by running
  44                         \texttt{\$ cd /home/student/tt2015}\\
  45                 & 4. & Compile the echo server by running
  46                         \texttt{\# cd code/server \&\& make}\\
  47                 & 5. & Start the echo server by running
  48                         \texttt{\# cd code/server \&\& java Main}\\
  49                 & 6. & Generate all test cases by running
  50                         \texttt{\$ python code/client/gen.py}\\
  51         \hline
  52         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  53         \hline\hline
  54         Check 4 & \multicolumn{2}{l|}{Test the tool environment.}\\
  55         \hline
  56         \multirow{3}{*}{Course of action}
  57                 & 1. & Initialize the SUT as in \emph{Check 3}\\
  58                 & 2. & Execute the test script by running
  59                         \texttt{\# code/client/helloworld.py}\\
  60                 & 3. & Verify the console displays a success message.\\
  61         \hline
  62         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  63         \hline\hline
  64         Check 5 & \multicolumn{2}{l|}{All test inputs and scripts are present.}\\
  65         \hline
  66         \multirow{2}{*}{Course of action}
  67                 & 1. & Boot the SUT as in \emph{Check 1}.\\
  68                 & 2. & Verify that the test generation script is present by running
  69                         \texttt{\$ file code/client/test.py}\\
  70         \hline
  71         Passed & \multicolumn{2}{l|}{\textit{Yes/No}}\\
  72         \hline
  73         \caption{Preflight checklist\label{tbl:preflight}}
  74 \end{longtable}
  75
  76 \subsection{Testing of SUT}
  77 The SUT is a series of services for other computer programs with no end-user
  78 facing interface. Therefore the SUT will be tested solely by calling it's
  79 services through various automated scripts. An automated test suite will be
  80 available which executes all these automated scripts and aggregates their
  81 results to asses whether or not the SUT has passed the test.
  82
  83 The implementation of the SUT is tested using black box testing techniques. A
  84 series of tests asses the correctness of the implementation with regards to the
  85 TCP specification. These tests are specified in Table~\ref{tbl:testpairs}. The test cases aim to cover the most interesting parts of the TCP
  86 specification.
  87
  88 To cover the TCP specification as complete as possible while still maintaining
  89 a feasible test suite the tests are divided into equivalence partitions. Below
  90 these partitions are given.
  91
  92 \begin{enumerate}
  93         \item \emph{Number of segments} in request~\footnote{A request is
  94                 considered establishing a connection (handshake) and a number of
  95                 payload segments}
  96                 \begin{enumerate}
  97                         \item 0 payload segments
  98                         \item 1 payload segments
  99                         \item n=small payload segments (1 byte)
 100                         \item n=big payload segments (65495 bytes)
 101                 \end{enumerate}
 102         \item \emph{source port}
 103                 \begin{enumerate}
 104                         \item Correct
 105                         \item Incorrect
 106                 \end{enumerate}
 107         \item \emph{destination port}
 108                 \begin{enumerate}
 109                         \item Correct
 110                         \item Incorrect
 111                 \end{enumerate}
 112         \item Bit errors in \emph{payload}
 113                 \begin{enumerate}
 114                         \item Correct payload
 115                         \item Payload with bit flips that do not show in checksum
 116                         \item Payload with bit flips that do show in checksum
 117                 \end{enumerate}
 118         \item \emph{checksum}
 119                 \begin{enumerate}
 120                         \item Correct
 121                         \item Incorrect
 122                 \end{enumerate}
 123         \item \emph{Segment order}
 124                 \begin{enumerate}
 125                         \item Correct
 126                         \item Out of order
 127                         \item Missing Segments
 128                 \end{enumerate}
 129 \end{enumerate}
 130
 131 These partitions were chosen since they correspond to key parts of the TCP
 132 specification.
 133
 134 TCP segments are send over a TCP connection from a \emph{source} to a \emph{destination port}. Therefore segments which are received that have a
 135 source or destination port set to an incorrect value should not be regarded
 136 as segments belonging to the connection by the SUT.
 137
 138 TCP uses a \emph{checksum} to catch any error introduced in headers, when this
 139 checksum does not match the actual computed checksum the SUT should
 140 disregard the received segment.
 141
 142 The TCP checksum is also an inherently weak one, as it is simply the
 143 bitwise negation of the addition, in ones complement arithmetic,
 144 of all 16 bit words in the header and data of the segment (excluding the
 145 checksum itself). Therefore any \emph{bit error} where the ones complement value
 146 of one word
 147 increases by one, and the value of another decreases by one, is undetected.
 148 The SUT should exhibit the same behavior and accept packets where these type
 149 of bit errors occur.
 150
 151 TCP guarantees that segments are delivered \emph{in order}
 152 ,even when they are received
 153 out of order and that missing segments are resend. The SUT should
 154 exhibit the same behavior. If segments are received out of order it should
 155 either reassemble them when the missing packet has arrived or request them to
 156 be resend when the  Missing segments should be re-requested (by ACK-ing
 157 the correct sequence number).
 158
 159 \bigskip
 160
 161 Partitions 2 to 6 are tested using pairwise testing to keep the number of test
 162 cases feasible. The pairs are then all *except some where it does not make sense
 163 to do so) tested with the different request sizes of partition 1.
 164
 165 This is expressed in Table~\ref{tbl:testpairs}. In this table the first five
 166 columns represent the different options for the partitions 2 to 6 of the above
 167 enumeration. The last four columns are the different number segments as
 168 described in the partition 1 of the above enumeration. These cells identify
 169 individual test cases by a number. An \xmark in the cell indicates that this
 170 test case can not be created as it is not possible with that number of segments
 171 (eg. sending segments out of order when the number of segments is 1).
 172
 173 \setcounter{TCC}{1}
 174 \begin{table}[H]
 175         \centering
 176         \begin{tabular}{|l|l|l|l|l|l||l|l|l|l|}
 177                 \hline
 178                 & \multicolumn{9}{c|}{\textbf{Partition}}\\
 179                 \hline
 180                 & 4 & 5 & 3 & 6 & 2 & 1a & 1b & 1c & 1d\\
 181                 \hline\hline
 182                 \multirow{9}{*}{Instance}
 183                 & a & a & a & a & a & \doTCC & \doTCC & \doTCC & \doTCC\\
 184                 & a & b & b & c & b & \xmark & \xmark & \doTCC & \doTCC\\
 185                 & c & a & b & a & b & \xmark & \xmark & \doTCC & \doTCC\\
 186                 & c & b & a & c & a & \xmark & \xmark & \doTCC & \doTCC\\
 187                 & b & a & b & c & a & \xmark & \xmark & \doTCC & \doTCC\\
 188                 & b & b & a & b & b & \xmark & \xmark & \doTCC & \doTCC\\
 189                 & c & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
 190                 & b & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
 191                 & a & b & b & b & a & \xmark & \xmark & \doTCC & \doTCC\\
 192                 \hline
 193         \end{tabular}
 194 \caption{Combinations of test cases}
 195 \label{tbl:testpairs}
 196 \end{table}
 197
 198 \subsection{Quality, completeness and coverage of tests}
 199
 200 The network packets used in testing are constructed from prerecorded, known to
 201 be correct, network traffic. These packets are then modified with well used and
 202 field tested tools. Due to this the chance of errors in the test cases is quite
 203 low. However, no formal proof of correctness of the test cases is present, this
 204 means that any defects found might not be the result of a fault in the SUT.
 205 Therefore detected defects should only indicate there is a high chance that
 206 there is a fault in the SUT and can not result directly in the conclusion that
 207 there actually is one.
 208
 209 \bigskip
 210
 211 Due to the nature of black-box testing coverage of the code in the
 212 implementation of the SUT is unknown. However completeness of the tests over
 213 the specification of the SUT can be assessed.
 214
 215 \bigskip
 216
 217 Due to the clear and exhaustive specification of TCP the completeness of the
 218 test suite can be clearly assessed.
 219
 220 As always, $100\%$ completeness is not feasible, therefore test cases are
 221 carefully selected to cover the most interesting parts of the TCP specification
 222 to ensure a complete but feasible test suite.
 223
 224 To further increase the coverage of the test suites tests are randomized. The
 225 tests which test the handling of \emph{bit errors}, changes in the \emph{packet
 226 order} and \emph{dropped packets} randomize where they introduce an error. The
 227 test suite runs these tests multiple times to increase the likelihood that they
 228 discover a fault which is only present when an error occurs in a certain
 229 position.
 230
 231 To further decrease the number of tests needed test cases are divided into
 232 equivalence partitions and the combination of cases as described in
 233 Table~\ref{tbl:testpairs} ensures that all partitions are
 234 covered and the number of individual tests is still feasible.
 235
 236
 237 %
 238 % wat ik ook probeer ik krijg de eerste collum
 239 % zijn tekst niet verticaal gecentered
 240 %
 241
 242
 243 \subsection{Test suite}
 244
 245 Before executing the test suite the test environment has to be initialized.
 246
 247 \begin{enumerate}
 248         \item Boot the vm using VirtualBox.
 249         \item Setup iptables by executing \texttt{\# code/iptables.sh}
 250         \item Navigate to the working directory by running
 251                 \texttt{\$ cd /home/student/tt2015}
 252         \item Start the echo server by running
 253                 \texttt{\# cd code/server \&\& Java Main}
 254 \end{enumerate}
 255
 256 \subsubsection{Preflight checks}
 257 The we do the preflight checks as defined in Table~\ref{tbl:preflight}.
 258
 259 \subsubsection{Test Cases}
 260 If the SUT passes the preflight checks the actual test cases can be executed.
 261 Table~\ref{tbl:testcases} shows the expected results of each of the test cases
 262 described in Table~\ref{tbl:testpairs}.
 263
 264 \setcounter{TCC}{1}
 265 \begin{table}[H]
 266         \centering
 267     \begin{tabular}{|l|p{.7\linewidth}|}
 268         \hline
 269         Test number & Expected results\\
 270         \hline\hline
 271         \doTCC & An ACK\# of the send sequence number + 1.\\  \hline
 272         \doTCC & An ACK\# of the sequence number of the last send segment + the
 273                 size of the payload of that segment.\\  \hline
 274         \doTCC & An ACK\# of the sequence number of the last send segment + the
 275                 size of the payload of that segment.\\  \hline
 276         \doTCC & An ACK\# of the sequence number of the last send segment + the
 277                 size of the payload of that segment.\\  \hline
 278         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 279                 corrupted is received for each consecutive segment send.\\
 280         $\vdots$ & \\
 281         \setcounter{TCC}{14}
 282         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 283                 corrupted is received for each consecutive segment send.\\  \hline
 284         \doTCC & The segment is not attributed to the current connection
 285                 and therefore no ACK\# is received. \\  \hline
 286         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 287                 corrupted is received for each consecutive segment send.\\  \hline
 288         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 289                 corrupted is received for each consecutive segment send.\\  \hline
 290         \doTCC & The segment is not attributed to the current connection
 291                 and therefore no ACK\# is received. \\  \hline
 292         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 293                 corrupted is received for each consecutive segment send.\\  \hline
 294         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 295                 corrupted is received for each consecutive segment send.\\ \hline
 296         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 297                 corrupted is received for each consecutive segment send.\\  \hline
 298         \doTCC & The ACK\# for the SEQ\# of the first segments which is
 299                 corrupted is received for each consecutive segment send.\\ \hline
 300     \end{tabular}
 301 \caption{Expected results of test cases}
 302 \label{tbl:testcases}
 303 \end{table}
 304
 305 % Bij Ramons afwezigheid
 306 % Paul Vitero (linkerkant lange gang)
 307 % verdieping Mercator
 308
 309
 310 %\begin{longtable}{|p{.2\linewidth}|p{.8\linewidth}|}
 311         %\hline
 312         %Nr & 1 \\\hline
 313         %Title & Single valid request with 1byte payload. \\\hline
 314         %Input & Generated packets. \\\hline
 315         %Expected output & Packets echoed back by Echo-Server. \\\hline
 316         %\multirow{2}{*}{Course of action}
 317  %& 1. Use the steps listed above in order to start the SUT. \\
 318  %& 2. Execute the script by running \texttt{\# code/client/tests/1.py} \\\hline
 319         %Valid trace & Verify that the script prints 'Success'. \\\hline
 320         %\hline
 321 %
 322         %Nr & 2 \\\hline
 323         %Title & Single valid request with 65495bytes payload. \\\hline
 324         %Input & Generated packets. \\\hline
 325         %Expected output & Packets echoed back by Echo-Server. \\\hline
 326         %\multirow{2}{*}{Course of action}
 327         %& 1. Use the steps listed above in order to start the SUT. \\
 328         %& 2. Execute the script by running \texttt{\# code/client/tests/2.py} \\\hline
 329         %Valid trace & Verify that the script prints 'Success'. \\\hline
 330         %\hline
 331 %
 332         %Nr & 3 \\\hline
 333         %Title & 5 valid requests with 1byte payload. \\\hline
 334         %Input & Generated packets. \\\hline
 335         %Expected output & Packets echoed back by Echo-Server, in the same order as the client sent them. \\\hline
 336         %\multirow{2}{*}{Course of action}
 337         %& 1. Use the steps listed above in order to start the SUT. \\
 338         %& 2. Execute the script by running \texttt{\# code/client/tests/3.py} \\\hline
 339         %Valid trace & Verify that the script prints 'Success'. \\\hline
 340         %\hline
 341 %
 342         %Nr & 4 \\\hline
 343         %Title & 5 valid requests with 65495bytes payload. \\\hline
 344         %Input & Generated packets with 65495bytes payload. \\\hline
 345         %Expected output & Packets echoed back by Echo-Server, in the same order as the client sent them. \\\hline
 346         %\multirow{2}{*}{Course of action}
 347         %& 1. Use the steps listed above in order to start the SUT. \\
 348         %& 2. Execute the script by running \texttt{\# code/client/tests/4.py} \\\hline
 349         %Valid trace & Verify that the script prints 'Success'. \\\hline
 350         %\hline
 351 %
 352         %Nr & 5 \\\hline
 353         %Title & 5 valid requests with 1byte payload sent out of order. \\\hline
 354         %Input & Generated packets with 1byte payload, two packets are swapped in position. \\\hline
 355         %Expected output & All requests sent up to and including
 356          %the swapped packet with the lowest sequence number, the remaining packets are dropped. \\\hline
 357         %\multirow{2}{*}{Course of action}
 358         %& 1. Use the steps listed above in order to start the SUT. \\
 359         %& 2. Execute the script by running \texttt{\# code/client/tests/5.py} \\\hline
 360         %Valid trace & Verify that the script prints 'Success'. \\\hline
 361         %\hline
 362 %
 363         %Nr & 6 \\\hline
 364         %Title & Request with corrupted source port. \\\hline
 365         %Input & Generated packets with 1byte payload, in these packets the source port number is increased by one. \\\hline
 366         %Expected output & - \\\hline
 367         %\multirow{2}{*}{Course of action}
 368         %& 1. Use the steps listed above in order to start the SUT. \\
 369         %& 2. Execute the script by running \texttt{\# code/client/tests/6.py} \\\hline
 370         %Valid trace & Verify that the script prints 'Success'. \\\hline
 371         %\hline
 372 %
 373 %
 374         %Nr & 6 \\\hline
 375         %Title & Request with corrupted destination port. \\\hline
 376         %Input & Generated packets with 1byte payload, in these packets the destination port number is increased by one. \\\hline
 377         %Expected output & - \\\hline
 378         %\multirow{2}{*}{Course of action}
 379         %& 1. Use the steps listed above in order to start the SUT. \\
 380         %& 2. Execute the script by running \texttt{\# code/client/tests/6.py} \\\hline
 381         %Valid trace & Verify that the script prints 'Success'. \\\hline
 382         %\hline
 383 %
 384 %\end{longtable}
 385
 386 %\begin{tabularx}{\linewidth}{| l | X|}
 387 %\hline
 388 %Nr & 1 \\\hline
 389 %Title & Single valid request. \\\hline
 390 %Input & Pcap file with prerecorded valid packets. \\\hline
 391 %Expected output & Pcap file with valid response to request. \\\hline
 392 %Course of action & \begin{enumerate}
 393 %       \item Execute \emph{./scripts/tests/case1-single-valid.sh}
 394 %       \item Load \emph{output/case1.pcap} with ...
 395 %\end{enumerate} \\\hline
 396 %Valid trace & \begin{enumerate}
 397 %       \item \textbf{Hier packets benoemen?}
 398 %\end{enumerate} \\\hline
 399 %\end{tabularx}
 400 %
 401 %\begin{tabularx}{\linewidth}{| l | X|}
 402 %       \hline
 403 %       Nr & 2 \\\hline
 404 %Title & Single request with corrupted checksum. \\\hline
 405 %       Input & Pcap file used as \emph{test-case 1} input. \\\hline
 406 %       Expected output & No response from SUT, logs with rejected packets. \\\hline
 407 %       Course of action & \begin{enumerate}
 408 %               \item Load input pcap file into ....
 409 %               \item Corrupt checksum of loaded packets.
 410 %               \item Save resulting packets as pcap file.
 411 %               \item Load new pcap file into ...
 412 %               \item Replay new pcap file.
 413 %               \item Record SUT response using...
 414 %               \item Extract log with rejected packets.
 415 %               \item Save recorded packets as a pcap file.
 416 %               \item Analyze packets in resulting file.
 417 %       \end{enumerate} \\\hline
 418 %       Valid trace & \begin{enumerate}
 419 %               \item \textbf{Aangeven welke packets corrupted zijn?}
 420 %       \end{enumerate} \\\hline
 421 %\end{tabularx}
 422 %\end{table}