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{table: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 \newcounter{TCC}
 173 \setcounter{TCC}{1}
 174 \newcommand{\doTCC}{\theTCC \stepcounter{TCC}}
 175 \begin{table}[H]
 176         \centering
 177         \begin{tabular}{|l|l|l|l|l|l||l|l|l|l|}
 178                 \hline
 179                 & \multicolumn{9}{c|}{\textbf{Partition}}\\
 180                 \hline
 181                 & 4 & 5 & 3 & 6 & 2 & 1a & 1b & 1c & 1d\\
 182                 \hline\hline
 183                 \multirow{9}{*}{Instance}
 184                 & a & a & a & a & a & \doTCC & \doTCC & \doTCC & \doTCC\\
 185                 & a & b & b & c & b & \xmark & \xmark & \doTCC & \doTCC\\
 186                 & c & a & b & a & b & \xmark & \xmark & \doTCC & \doTCC\\
 187                 & c & b & a & c & a & \xmark & \xmark & \doTCC & \doTCC\\
 188                 & b & a & b & c & a & \xmark & \xmark & \doTCC & \doTCC\\
 189                 & b & b & a & b & b & \xmark & \xmark & \doTCC & \doTCC\\
 190                 & c & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
 191                 & b & b & b & a & b & \xmark & \doTCC & \doTCC & \doTCC\\
 192                 & a & b & b & b & a & \xmark & \xmark & \doTCC & \doTCC\\
 193                 \hline
 194 \end{tabular}
 195 \caption{Combinations of test cases}
 196 \label{table:testpairs}
 197 \end{table}
 198
 199 \subsection{Quality, completeness and coverage of tests}
 200
 201 The network packets used in testing are constructed from prerecorded, known to
 202 be correct, network traffic. These packets are then modified with well used and
 203 field tested tools. Due to this the chance of errors in the test cases is quite
 204 low. However, no formal proof of correctness of the test cases is present, this
 205 means that any defects found might not be the result of a fault in the SUT.
 206 Therefore detected defects should only indicate there is a high chance that
 207 there is a fault in the SUT and can not result directly in the conclusion that
 208 there actually is one.
 209
 210 \bigskip
 211
 212 Due to the nature of black-box testing coverage of the code in the
 213 implementation of the SUT is unknown. However completeness of the tests over
 214 the specification of the SUT can be assessed.
 215
 216 \bigskip
 217
 218 Due to the clear and exhaustive specification of TCP the completeness of the
 219 test suite can be clearly assessed.
 220
 221 As always, $100\%$ completeness is not feasible, therefore test cases are
 222 carefully selected to cover the most interesting parts of the TCP specification
 223 to ensure a complete but feasible test suite.
 224
 225 To further increase the coverage of the test suites tests are randomized. The
 226 tests which test the handling of \emph{bit errors}, changes in the \emph{packet
 227 order} and \emph{dropped packets} randomize where they introduce an error. The
 228 test suite runs these tests multiple times to increase the likelihood that they
 229 discover a fault which is only present when an error occurs in a certain
 230 position.
 231
 232 To further decrease the number of tests needed test cases are divided into
 233 equivalence partitions and the combination of cases as described in
 234 Table~\ref{table:testpairs} ensures that all partitions are
 235 covered and the number of individual tests is still feasible.
 236
 237
 238 %
 239 % wat ik ook probeer ik krijg de eerste collum
 240 % zijn tekst niet verticaal gecentered
 241 %
 242
 243
 244 \subsection{Test cases}
 245
 246 Before every test case use the following steps to initialize the testing environment.
 247
 248 \begin{enumerate}
 249         \item Boot the vm using VirtualBox.
 250         \item Setup iptables by executing \texttt{\# code/iptables.sh}
 251         \item Navigate to the working directory by running \texttt{\$ cd /home/student/tt2015}
 252         \item Start the echo server by running \texttt{\# cd code/server \&\& java Main}
 253 \end{enumerate}
 254
 255 \begin{longtable}{|p{.2\linewidth}|p{.8\linewidth}|}
 256         \hline
 257         Nr & 1 \\\hline
 258         Title & Single valid request with 1byte payload. \\\hline
 259         Input & Generated packets. \\\hline
 260         Expected output & Packets echoed back by Echo-Server. \\\hline
 261         \multirow{2}{*}{Course of action}
 262  & 1. Use the steps listed above in order to start the SUT. \\
 263  & 2. Execute the script by running \texttt{\# code/client/tests/1.py} \\\hline
 264         Valid trace & Verify that the script prints 'Success'. \\\hline
 265         \hline
 266
 267         Nr & 2 \\\hline
 268         Title & Single valid request with 65495bytes payload. \\\hline
 269         Input & Generated packets. \\\hline
 270         Expected output & Packets echoed back by Echo-Server. \\\hline
 271         \multirow{2}{*}{Course of action}
 272         & 1. Use the steps listed above in order to start the SUT. \\
 273         & 2. Execute the script by running \texttt{\# code/client/tests/2.py} \\\hline
 274         Valid trace & Verify that the script prints 'Success'. \\\hline
 275         \hline
 276
 277         Nr & 3 \\\hline
 278         Title & 5 valid requests with 1byte payload. \\\hline
 279         Input & Generated packets. \\\hline
 280         Expected output & Packets echoed back by Echo-Server, in the same order as the client sent them. \\\hline
 281         \multirow{2}{*}{Course of action}
 282         & 1. Use the steps listed above in order to start the SUT. \\
 283         & 2. Execute the script by running \texttt{\# code/client/tests/3.py} \\\hline
 284         Valid trace & Verify that the script prints 'Success'. \\\hline
 285         \hline
 286
 287         Nr & 4 \\\hline
 288         Title & 5 valid requests with 65495bytes payload. \\\hline
 289         Input & Generated packets with 65495bytes payload. \\\hline
 290         Expected output & Packets echoed back by Echo-Server, in the same order as the client sent them. \\\hline
 291         \multirow{2}{*}{Course of action}
 292         & 1. Use the steps listed above in order to start the SUT. \\
 293         & 2. Execute the script by running \texttt{\# code/client/tests/4.py} \\\hline
 294         Valid trace & Verify that the script prints 'Success'. \\\hline
 295         \hline
 296
 297         Nr & 5 \\\hline
 298         Title & 5 valid requests with 1byte payload sent out of order. \\\hline
 299         Input & Generated packets with 1byte payload, two packets are swapped in position. \\\hline
 300         Expected output & All requests sent up to and including
 301          the swapped packet with the lowest sequence number, the remaining packets are dropped. \\\hline
 302         \multirow{2}{*}{Course of action}
 303         & 1. Use the steps listed above in order to start the SUT. \\
 304         & 2. Execute the script by running \texttt{\# code/client/tests/5.py} \\\hline
 305         Valid trace & Verify that the script prints 'Success'. \\\hline
 306         \hline
 307 \end{longtable}
 308
 309 %\begin{tabularx}{\linewidth}{| l | X|}
 310 %\hline
 311 %Nr & 1 \\\hline
 312 %Title & Single valid request. \\\hline
 313 %Input & Pcap file with prerecorded valid packets. \\\hline
 314 %Expected output & Pcap file with valid response to request. \\\hline
 315 %Course of action & \begin{enumerate}
 316 %       \item Execute \emph{./scripts/tests/case1-single-valid.sh}
 317 %       \item Load \emph{output/case1.pcap} with ...
 318 %\end{enumerate} \\\hline
 319 %Valid trace & \begin{enumerate}
 320 %       \item \textbf{Hier packets benoemen?}
 321 %\end{enumerate} \\\hline
 322 %\end{tabularx}
 323 %
 324 %\begin{tabularx}{\linewidth}{| l | X|}
 325 %       \hline
 326 %       Nr & 2 \\\hline
 327 %Title & Single request with corrupted checksum. \\\hline
 328 %       Input & Pcap file used as \emph{test-case 1} input. \\\hline
 329 %       Expected output & No response from SUT, logs with rejected packets. \\\hline
 330 %       Course of action & \begin{enumerate}
 331 %               \item Load input pcap file into ....
 332 %               \item Corrupt checksum of loaded packets.
 333 %               \item Save resulting packets as pcap file.
 334 %               \item Load new pcap file into ...
 335 %               \item Replay new pcap file.
 336 %               \item Record SUT response using...
 337 %               \item Extract log with rejected packets.
 338 %               \item Save recorded packets as a pcap file.
 339 %               \item Analyze packets in resulting file.
 340 %       \end{enumerate} \\\hline
 341 %       Valid trace & \begin{enumerate}
 342 %               \item \textbf{Aangeven welke packets corrupted zijn?}
 343 %       \end{enumerate} \\\hline
 344 %\end{tabularx}
 345 %\end{table}