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