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{longtabu}{|l|X|}
  11         \hline
  12         Check 1 & Get the SUT in a workable state. \\
  13         \hline
  14         Course of action &
  15                 \begin{enumerate}
  16                         \item Import the VirtualBox image into VirtualBox.
  17                         \item Boot the vm.
  18                         \item Verify the SUT booted successfully and the network modules
  19                                 are loaded.
  20                 \end{enumerate}\\
  21         \hline Passed & \textit{Yes/No} \\
  22         \hline\hline
  23         Check 2 & Verify the SUT is complete. \\\hline
  24         Course of action &
  25                 \begin{enumerate}
  26                         \item Boot the SUT as in \emph{Check 1}.
  27                         \item Verify the loopback device exists by running
  28                                 \texttt{\$ ifconfig}.
  29                         \item Verify the \emph{echo-server} is present on the system.
  30                         \item Verify \emph{Scapy} is present on the system by running
  31                                 \texttt{\$ scapy}.
  32                         \item Verify all scripts used for testing are present on the
  33                                 system.
  34                 \end{enumerate}\\
  35         \hline
  36         Passed & \textit{Yes/No}\\
  37         Check 3 & Initialize the testing environment.\\
  38         \hline
  39         Course of action &
  40                         \begin{enumerate}
  41                                 \item Boot the SUT as in \emph{Check 1}.
  42                                 \item Setup iptables by executing
  43                                         \texttt{\# code/iptables.sh}~\footnote{ The IPTables script
  44                                         ensures that the OS does not drop packets due to an the
  45                                         unknown source.}
  46                                 \item Navigate to the working directory by running
  47                                         \texttt{\$ cd /home/student/tt2015}
  48                                 \item Compile the echo server by running
  49                                         \texttt{\# cd code/server \&\& make \&\& cd -}
  50                                 \item Start the echo server by running
  51                                         \texttt{\# cd code/server \&\& java Main}
  52                 \end{enumerate}\\
  53         \hline
  54         Passed & \textit{Yes/No}\\
  55         \hline\hline
  56         Check 4 & Test the tool environment.\\
  57         \hline
  58         Course of action &
  59                 \begin{enumerate}
  60                         \item Initialize the SUT as in \emph{Check 3}
  61                         \item Execute the test script by running
  62                                 \texttt{\# code/client/helloworld.py}.
  63                         \item Verify the console displays a success message.
  64                 \end{enumerate}\\
  65         \hline
  66         Passed & \textit{Yes/No}\\
  67         \hline\hline
  68         Check 5 & All test inputs and scripts are present. \\\hline
  69         % DIT MOET NOG EVEN ANDERS
  70         Course of action &
  71                 \begin{enumerate}
  72                         \item Boot the SUT as in \emph{Check 1}.
  73                         \item Execute the command \texttt{ls scripts/tests}
  74                         \item Verify that there is a file named case$X$ for each test case $X$
  75                         \item Use \emph{ls packets}
  76                         \item Verify that there is a file named \texttt{single.pcap} and
  77                         \texttt{multi.pcap}.
  78                 \end{enumerate}\\
  79         \hline
  80         Passed & \textit{Yes/No}\\
  81         \hline
  82         \caption{Preflight checklist\label{tbl:preflight}}
  83 \end{longtabu}
  84
  85 \subsection{Testing of SUT}
  86 The SUT is a series of services for other computer programs with no end-user
  87 facing interface. Therefore the SUT will be tested solely by calling it's
  88 services through various automated scripts. An automated test suite will be
  89 available which executes all these automated scripts and aggregates their
  90 results to asses whether or not the SUT has passed the test.
  91
  92 The implementation of the SUT is tested using black box testing techniques. A
  93 series of tests asses the correctness of the implementation with regards to the
  94 TCP specification. These tests are specified in Table~\textbf{referentie naar
  95 tests-tabel}. The test cases aim to cover the most interesting parts of the TCP
  96 specification.
  97
  98 To cover the TCP specification as complete as possible while still maintaining
  99 a feasible test suite the tests are divided into equivalence partitions. Below
 100 these partitions are given.
 101
 102 \begin{enumerate}
 103         \item \emph{Number of packets} in request~\footnote{A request is considered
 104                 establishing a connection (handshake) and a number of payload packets}
 105                 \begin{enumerate}
 106                         \item 0 payload packets
 107                         \item 1 payload packet
 108                         \item n=small payload packets
 109                         \item n=big payload packets
 110                 \end{enumerate}
 111         \item Correct or incorrect \emph{source port}
 112         \item Correct or incorrect \emph{destination port}
 113         \item Bits flipped in \emph{payload}
 114                 \begin{enumerate}
 115                         \item Correct payload
 116                         \item Payload with bit flips
 117                         \item Payload with odd number of bits flipped
 118                 \end{enumerate}
 119         \item Correct or Incorrect \emph{checksum}
 120         \item Packets received in or out of order, or missing packets
 121 \end{enumerate}
 122
 123 These partitions were chosen since they correspond to key parts of the TCP
 124 specification.
 125
 126 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
 127 source or destination port set to an incorrect value should not be regarded
 128 as segments belonging to the connection.
 129
 130 TCP uses a \emph{checksum} to catch any error introduced in headers, when this
 131 checksum does not match the actual computed checksum the packet should be
 132 disregarded.
 133
 134 The TCP checksum is also an inherently weak one, as it is simply the
 135 bitwise negation of the addition in ones complement arithmetic
 136 of all 16 bit words in the header and data of the segment (excluding the
 137 header). Therefore any bit error where the ones complement value of one word
 138 increases by one, and the value of another decreases by one, is undetected.
 139 The SUT should exhibit the same behavior and accept packets where these type
 140 of bit error occur.
 141
 142 \textbf{hier iets over waarom deze partities relevant zijn! Waarom odd en
 143 even number of bits flipped bijv interessant?}
 144 \bigskip
 145
 146 Partitions 2 to 6 are tested using pairwise testing to keep the number of test
 147 cases feasible. The pairs are then all *except some where it does not make sense
 148 to do so) tested with the different request sizes of partition 1.
 149
 150 This is expressed in Table~\ref{table:testpairs}.
 151
 152 \begin{table}
 153 % DIT MAAK IK NOG EVEN MOOI
 154         \begin{tabularx}{\linewidth}{p{2cm} | l | p{2cm} | l | p{1cm} || c | c | p{1.3cm} | p{1.3cm}}
 155         \textbf{Payload}      & \textbf{checksum}  & \textbf{destination port} & \textbf{order}         & \textbf{source port} & \textbf{payload 0} & \textbf{payload 1} & \textbf{payload small} & \textbf{payload big} \\  \hline \hline
 156         Correct               & Correct   & Correct          & In order       & Correct     & \checkmark & \checkmark & \checkmark & \checkmark \\  \hline
 157         Correct               & Incorrect & Incorrect        & Missing packet & Incorrect   & \xmark & \xmark & \checkmark & \checkmark \\  \hline
 158         odd\# of bits flipped  & Correct   & Incorrect        & Out of order   & Incorrect   & \xmark & \xmark & \checkmark & \checkmark \\  \hline
 159         odd\# of bits flipped  & Incorrect & Correct          & Missing packet & Correct     & \xmark & \xmark & \checkmark & \checkmark \\  \hline
 160         even\# of bits flipped & Correct   & Incorrect        & Missing packet & Correct     & \xmark & \xmark & \checkmark & \checkmark \\  \hline
 161         even\# of bits flipped & Incorrect & Correct          & Out of order   & Incorrect   & \xmark & \xmark & \checkmark & \checkmark \\  \hline
 162         odd\# of bits flipped  & Incorrect & Incorrect        & In order       & Incorrect   & \checkmark & \checkmark & \checkmark & \checkmark \\  \hline
 163         even\# of bits flipped & Incorrect & Incorrect        & In order       & Incorrect   & \checkmark & \checkmark & \checkmark & \checkmark \\  \hline
 164         Correct               & Incorrect & Incorrect        & Out of order   & Correct     & \xmark & \xmark & \checkmark & \checkmark \\
 165 \end{tabularx}
 166 \caption{Combinations of test cases}
 167 \label{table:testpairs}
 168 \end{table}
 169
 170 \subsection{Quality, completeness and coverage of tests}
 171
 172 The network packets used in testing are constructed from prerecorded, known to
 173 be correct, network traffic. These packets are then modified with well used and
 174 field tested tools. Due to this the chance of errors in the test cases is quite
 175 low. However, no formal proof of correctness of the test cases is present, this
 176 means that any defects found might not be the result of a fault in the SUT.
 177 Therefore detected defects should only indicate there is a high chance that
 178 there is a fault in the SUT and can not result directly in the conclusion that
 179 there actually is one.
 180
 181 \bigskip
 182
 183 Due to the nature of black-box testing coverage of the code in the
 184 implementation of the SUT is unknown. However completeness of the tests over
 185 the specification of the SUT can be assessed.
 186
 187 \bigskip
 188
 189 Due to the clear and exhaustive specification of TCP the completeness of the
 190 test suite can be clearly assessed.
 191
 192 As always, $100\%$ completeness is not feasible, therefore test cases are
 193 carefully selected to cover the most interesting parts of the TCP specification
 194 to ensure a test suite.
 195
 196 To further decrease the number of tests needed test cases are divided into
 197 equivalence partitions and the combination of cases as described in
 198 Table~\ref{table:testpairs} ensures that all partitions are
 199 covered and the number of individual tests is still feasible.
 200
 201
 202 %
 203 % wat ik ook probeer ik krijg de eerste collum
 204 % zijn tekst niet verticaal gecentered
 205 %
 206
 207
 208 \subsection{Test cases}
 209
 210 %\begin{table}
 211 %\begin{tabularx}{\linewidth}{| l | X|}
 212 %\hline
 213 %Nr & 1 \\\hline
 214 %Title & Single valid request. \\\hline
 215 %Input & Pcap file with prerecorded valid packets. \\\hline
 216 %Expected output & Pcap file with valid response to request. \\\hline
 217 %Course of action & \begin{enumerate}
 218 %       \item Execute \emph{./scripts/tests/case1-single-valid.sh}
 219 %       \item Load \emph{output/case1.pcap} with ...
 220 %\end{enumerate} \\\hline
 221 %Valid trace & \begin{enumerate}
 222 %       \item \textbf{Hier packets benoemen?}
 223 %\end{enumerate} \\\hline
 224 %\end{tabularx}
 225 %
 226 %\begin{tabularx}{\linewidth}{| l | X|}
 227 %       \hline
 228 %       Nr & 2 \\\hline
 229 %Title & Single request with corrupted checksum. \\\hline
 230 %       Input & Pcap file used as \emph{test-case 1} input. \\\hline
 231 %       Expected output & No response from SUT, logs with rejected packets. \\\hline
 232 %       Course of action & \begin{enumerate}
 233 %               \item Load input pcap file into ....
 234 %               \item Corrupt checksum of loaded packets.
 235 %               \item Save resulting packets as pcap file.
 236 %               \item Load new pcap file into ...
 237 %               \item Replay new pcap file.
 238 %               \item Record SUT response using...
 239 %               \item Extract log with rejected packets.
 240 %               \item Save recorded packets as a pcap file.
 241 %               \item Analyze packets in resulting file.
 242 %       \end{enumerate} \\\hline
 243 %       Valid trace & \begin{enumerate}
 244 %               \item \textbf{Aangeven welke packets corrupted zijn?}
 245 %       \end{enumerate} \\\hline
 246 %\end{tabularx}
 247 %\end{table}