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 packets} in request~\footnote{A request is considered
  93                 establishing a connection (handshake) and a number of payload packets}
  94                 \begin{enumerate}
  95                         \item 0 payload packets
  96                         \item 1 payload packet
  97                         \item n=small payload packets
  98                         \item n=big payload packets
  99                 \end{enumerate}
 100         \item \emph{source port}
 101                 \begin{enumerate}
 102                         \item Correct
 103                         \item Incorrect
 104                 \end{enumerate}
 105         \item \emph{destination port}
 106                 \begin{enumerate}
 107                         \item Correct
 108                         \item Incorrect
 109                 \end{enumerate}
 110         \item Bits flipped in \emph{payload}
 111                 \begin{enumerate}
 112                         \item Correct payload
 113                         \item Payload with bit flips
 114                         \item Payload with odd number of bits flipped
 115                 \end{enumerate}
 116         \item \emph{checksum}
 117                 \begin{enumerate}
 118                         \item Correct
 119                         \item Incorrect
 120                 \end{enumerate}
 121         \item Packet order
 122                 \begin{enumerate}
 123                         \item Correct
 124                         \item Out of order
 125                         \item Missing packets
 126                 \end{enumerate}
 127 \end{enumerate}
 128
 129 These partitions were chosen since they correspond to key parts of the TCP
 130 specification.
 131
 132 TCP segments are send over a TCP connection from a \emph{source} to a \emph{destination port}. Therefore segments which are received which have a
 133 source or destination port set to an incorrect value should not be regarded
 134 as segments belonging to the connection.
 135
 136 TCP uses a \emph{checksum} to catch any error introduced in headers, when this
 137 checksum does not match the actual computed checksum the packet should be
 138 disregarded.
 139
 140 The TCP checksum is also an inherently weak one, as it is simply the
 141 bitwise negation of the addition in ones complement arithmetic
 142 of all 16 bit words in the header and data of the segment (excluding the
 143 header). Therefore any bit error where the ones complement value of one word
 144 increases by one, and the value of another decreases by one, is undetected.
 145 The SUT should exhibit the same behavior and accept packets where these type
 146 of bit error occur.
 147
 148 \textbf{hier iets over waarom deze partities relevant zijn! Waarom odd en
 149 even number of bits flipped bijv interessant?}
 150 \bigskip
 151
 152 Partitions 2 to 6 are tested using pairwise testing to keep the number of test
 153 cases feasible. The pairs are then all *except some where it does not make sense
 154 to do so) tested with the different request sizes of partition 1.
 155
 156 This is expressed in Table~\ref{table:testpairs}.
 157
 158 \begin{table}[H]
 159         \centering
 160         \begin{tabular}{|l|l|l|l|l|l|l|l|l|l|l|}
 161                 \hline
 162                 & \multicolumn{10}{c|}{\textbf{Partition}}\\
 163                 \hline
 164                 & \# & 4 & 5 & 3 & 6 & 2 & 1a & 1b & 1c & 1d\\
 165                 \hline\hline
 166                 \multirow{9}{*}{Instance}
 167                 & 1 & a & a & a & a & a & \checkmark & \checkmark & \checkmark & \checkmark\\
 168                 & 2 & a & b & b & c & b & \xmark & \xmark & \checkmark & \checkmark\\
 169                 & 3 & c & a & b & a & b & \xmark & \xmark & \checkmark & \checkmark\\
 170                 & 4 & c & b & a & c & a & \xmark & \xmark & \checkmark & \checkmark\\
 171                 & 5 & b & a & b & c & a & \xmark & \xmark & \checkmark & \checkmark\\
 172                 & 6 & b & b & a & b & b & \xmark & \xmark & \checkmark & \checkmark\\
 173                 & 7 & c & b & b & a & b & \checkmark & \checkmark & \checkmark & \checkmark\\
 174                 & 8 & b & b & b & a & b & \checkmark & \checkmark & \checkmark & \checkmark\\
 175                 & 9 & a & b & b & b & a & \xmark & \xmark & \checkmark & \checkmark\\
 176                 \hline
 177 \end{tabular}
 178 \caption{Combinations of test cases}
 179 \label{table:testpairs}
 180 \end{table}
 181
 182 \subsection{Quality, completeness and coverage of tests}
 183
 184 The network packets used in testing are constructed from prerecorded, known to
 185 be correct, network traffic. These packets are then modified with well used and
 186 field tested tools. Due to this the chance of errors in the test cases is quite
 187 low. However, no formal proof of correctness of the test cases is present, this
 188 means that any defects found might not be the result of a fault in the SUT.
 189 Therefore detected defects should only indicate there is a high chance that
 190 there is a fault in the SUT and can not result directly in the conclusion that
 191 there actually is one.
 192
 193 \bigskip
 194
 195 Due to the nature of black-box testing coverage of the code in the
 196 implementation of the SUT is unknown. However completeness of the tests over
 197 the specification of the SUT can be assessed.
 198
 199 \bigskip
 200
 201 Due to the clear and exhaustive specification of TCP the completeness of the
 202 test suite can be clearly assessed.
 203
 204 As always, $100\%$ completeness is not feasible, therefore test cases are
 205 carefully selected to cover the most interesting parts of the TCP specification
 206 to ensure a test suite.
 207
 208 To further decrease the number of tests needed test cases are divided into
 209 equivalence partitions and the combination of cases as described in
 210 Table~\ref{table:testpairs} ensures that all partitions are
 211 covered and the number of individual tests is still feasible.
 212
 213
 214 %
 215 % wat ik ook probeer ik krijg de eerste collum
 216 % zijn tekst niet verticaal gecentered
 217 %
 218
 219
 220 \subsection{Test cases}
 221
 222 %\begin{table}
 223 %\begin{tabularx}{\linewidth}{| l | X|}
 224 %\hline
 225 %Nr & 1 \\\hline
 226 %Title & Single valid request. \\\hline
 227 %Input & Pcap file with prerecorded valid packets. \\\hline
 228 %Expected output & Pcap file with valid response to request. \\\hline
 229 %Course of action & \begin{enumerate}
 230 %       \item Execute \emph{./scripts/tests/case1-single-valid.sh}
 231 %       \item Load \emph{output/case1.pcap} with ...
 232 %\end{enumerate} \\\hline
 233 %Valid trace & \begin{enumerate}
 234 %       \item \textbf{Hier packets benoemen?}
 235 %\end{enumerate} \\\hline
 236 %\end{tabularx}
 237 %
 238 %\begin{tabularx}{\linewidth}{| l | X|}
 239 %       \hline
 240 %       Nr & 2 \\\hline
 241 %Title & Single request with corrupted checksum. \\\hline
 242 %       Input & Pcap file used as \emph{test-case 1} input. \\\hline
 243 %       Expected output & No response from SUT, logs with rejected packets. \\\hline
 244 %       Course of action & \begin{enumerate}
 245 %               \item Load input pcap file into ....
 246 %               \item Corrupt checksum of loaded packets.
 247 %               \item Save resulting packets as pcap file.
 248 %               \item Load new pcap file into ...
 249 %               \item Replay new pcap file.
 250 %               \item Record SUT response using...
 251 %               \item Extract log with rejected packets.
 252 %               \item Save recorded packets as a pcap file.
 253 %               \item Analyze packets in resulting file.
 254 %       \end{enumerate} \\\hline
 255 %       Valid trace & \begin{enumerate}
 256 %               \item \textbf{Aangeven welke packets corrupted zijn?}
 257 %       \end{enumerate} \\\hline
 258 %\end{tabularx}
 259 %\end{table}