1 package edu.uci.iotproject;
3 import edu.uci.iotproject.comparison.ComparisonFunctions;
4 import edu.uci.iotproject.comparison.CompleteMatchPatternComparisonResult;
5 import edu.uci.iotproject.comparison.PatternComparisonTask;
6 import org.pcap4j.core.NotOpenException;
7 import org.pcap4j.core.PcapHandle;
8 import org.pcap4j.core.PcapNativeException;
9 import org.pcap4j.core.PcapPacket;
10 import org.pcap4j.packet.DnsPacket;
11 import org.pcap4j.packet.IpV4Packet;
12 import org.pcap4j.packet.TcpPacket;
14 import java.io.EOFException;
15 import java.net.UnknownHostException;
17 import java.util.concurrent.*;
21 * <p>Provides functionality for searching for the presence of a {@link FlowPattern} in a PCAP trace.</p>
24 * The (entire) PCAP trace is traversed and parsed on one thread (specifically, the thread that calls
25 * {@link #findFlowPattern()}). This thread builds a {@link DnsMap} using the DNS packets present in the trace and uses
26 * that {@code DnsMap} to reassemble {@link Conversation}s that <em>potentially</em> match the provided
27 * {@link FlowPattern} (in that one end/party of said conversations matches the hostname(s) specified by the given
28 * {@code FlowPattern}).
29 * These potential matches are then examined on background worker thread(s) to determine if they are indeed a (complete)
30 * matches of the provided {@code FlowPattern}.
33 * @author Janus Varmarken {@literal <jvarmark@uci.edu>}
34 * @author Rahmadi Trimananda {@literal <rtrimana@uci.edu>}
36 public class FlowPatternFinder {
38 /* Begin class properties */
40 * {@link ExecutorService} responsible for parallelizing pattern searches.
41 * Declared as static to allow for reuse of threads across different instances of {@code FlowPatternFinder} and to
42 * avoid the overhead of initializing a new thread pool for each {@code FlowPatternFinder} instance.
44 private static final ExecutorService EXECUTOR_SERVICE = Executors.newCachedThreadPool();
45 /* End class properties */
47 /* Begin instance properties */
49 * Holds a set of {@link Conversation}s that <em>potentially</em> match {@link #mPattern} since each individual
50 * {@code Conversation} is communication with the hostname identified by {@code mPattern.getHostname()}.
51 * Note that due to limitations of the {@link Set} interface (specifically, there is no {@code get(T t)} method),
52 * we have to resort to a {@link Map} (in which keys map to themselves) to "mimic" a set with {@code get(T t)}
55 * @see <a href="https://stackoverflow.com/questions/7283338/getting-an-element-from-a-set">this question on StackOverflow.com</a>
57 private final Map<Conversation, Conversation> mConversations;
59 private final DnsMap mDnsMap;
60 private final PcapHandle mPcap;
61 private final FlowPattern mPattern;
63 private final List<Future<CompleteMatchPatternComparisonResult>> mPendingComparisons = new ArrayList<>();
64 /* End instance properties */
67 * Constructs a new {@code FlowPatternFinder}.
68 * @param pcap an <em>open</em> {@link PcapHandle} that provides access to the trace that is to be examined.
69 * @param pattern the {@link FlowPattern} to search for.
71 public FlowPatternFinder(PcapHandle pcap, FlowPattern pattern) {
72 this.mConversations = new HashMap<>();
73 this.mDnsMap = new DnsMap();
74 this.mPcap = Objects.requireNonNull(pcap,
75 String.format("Argument of type '%s' cannot be null", PcapHandle.class.getSimpleName()));
76 this.mPattern = Objects.requireNonNull(pattern,
77 String.format("Argument of type '%s' cannot be null", FlowPattern.class.getSimpleName()));
81 * Starts the pattern search.
88 * Find patterns based on the FlowPattern object (run by a thread)
90 private void findFlowPattern() {
93 // TODO: The new comparison method is pending
94 // TODO: For now, just compare using one hostname and one list per FlowPattern
95 // List<String> hostnameList = mPattern.getHostnameList();
97 while ((packet = mPcap.getNextPacketEx()) != null) {
98 // Let DnsMap handle DNS packets.
99 if (packet.get(DnsPacket.class) != null) {
100 // Check if this is a valid DNS packet
101 mDnsMap.validateAndAddNewEntry(packet);
104 // For now, we only work support pattern search in TCP over IPv4.
105 final IpV4Packet ipPacket = packet.get(IpV4Packet.class);
106 final TcpPacket tcpPacket = packet.get(TcpPacket.class);
107 if (ipPacket == null || tcpPacket == null) {
111 String srcAddress = ipPacket.getHeader().getSrcAddr().getHostAddress();
112 String dstAddress = ipPacket.getHeader().getDstAddr().getHostAddress();
113 int srcPort = tcpPacket.getHeader().getSrcPort().valueAsInt();
114 int dstPort = tcpPacket.getHeader().getDstPort().valueAsInt();
115 // Is this packet related to the pattern; i.e. is it going to (or coming from) the cloud server?
116 boolean fromServer = mDnsMap.isRelatedToCloudServer(srcAddress, mPattern.getHostname());
117 boolean fromClient = mDnsMap.isRelatedToCloudServer(dstAddress, mPattern.getHostname());
118 // String currentHostname = hostnameList.get(hostIndex);
119 // boolean fromServer = mDnsMap.isRelatedToCloudServer(srcAddress, currentHostname);
120 // boolean fromClient = mDnsMap.isRelatedToCloudServer(dstAddress, currentHostname);
121 if (!fromServer && !fromClient) {
122 // Packet not related to pattern, skip it.
126 // Conversations (connections/sessions) are identified by the four-tuple
127 // (clientIp, clientPort, serverIp, serverPort) (see Conversation Javadoc).
128 // Create "dummy" conversation for looking up an existing entry.
129 Conversation conversation = fromClient ? new Conversation(srcAddress, srcPort, dstAddress, dstPort) :
130 new Conversation(dstAddress, dstPort, srcAddress, srcPort);
131 // Add the packet so that the "dummy" conversation can be immediately added to the map if no entry
132 // exists for the conversation that the current packet belongs to.
133 if (tcpPacket.getHeader().getFin()) {
134 // Record FIN packets.
135 conversation.addFinPacket(packet);
137 if (tcpPacket.getPayload() != null) {
138 // Record regular payload packets.
139 conversation.addPacket(packet, true);
141 // Note: does not make sense to call attemptAcknowledgementOfFin here as the new packet has no FINs
142 // in its list, so if this packet is an ACK, it would not be added anyway.
144 // Need to retain a final reference to get access to the packet in the lambda below.
145 final PcapPacket finalPacket = packet;
146 // Add the new conversation to the map if an equal entry is not already present.
147 // If an existing entry is already present, the current packet is simply added to that conversation.
148 mConversations.merge(conversation, conversation, (existingEntry, toMerge) -> {
149 // toMerge may not have any payload packets if the current packet is a FIN packet.
150 if (toMerge.getPackets().size() > 0) {
151 existingEntry.addPacket(toMerge.getPackets().get(0), true);
153 if (toMerge.getFinAckPairs().size() > 0) {
154 // Add the FIN packet to the existing entry.
155 existingEntry.addFinPacket(toMerge.getFinAckPairs().get(0).getFinPacket());
157 if (finalPacket.get(TcpPacket.class).getHeader().getAck()) {
158 existingEntry.attemptAcknowledgementOfFin(finalPacket);
160 return existingEntry;
162 // Refresh reference to point to entry in map (in case packet was added to existing entry).
163 conversation = mConversations.get(conversation);
164 if (conversation.isGracefullyShutdown()) {
165 // Conversation terminated gracefully, so we can now start analyzing it.
166 // Remove the Conversation from the map and start the analysis.
167 // Any future packets identified by the same four tuple will be tied to a new Conversation instance.
168 mConversations.remove(conversation);
169 // Create comparison task and send to executor service.
170 PatternComparisonTask<CompleteMatchPatternComparisonResult> comparisonTask =
171 new PatternComparisonTask<>(conversation, mPattern, ComparisonFunctions.COMPLETE_MATCH);
172 mPendingComparisons.add(EXECUTOR_SERVICE.submit(comparisonTask));
173 // Increment hostIndex to find the next
177 } catch (EOFException eofe) {
178 // TODO should check for leftover conversations in map here and fire tasks for those.
179 // TODO [cont'd] such tasks may be present if connections did not terminate gracefully or if there are longlived connections.
180 System.out.println("[ findFlowPattern ] Finished processing entire PCAP stream!");
181 System.out.println("[ findFlowPattern ] Now waiting for comparisons to finish...");
182 // Wait for all comparisons to finish, then output their results to std.out.
183 for(Future<CompleteMatchPatternComparisonResult> comparisonTask : mPendingComparisons) {
185 // Blocks until result is ready.
186 CompleteMatchPatternComparisonResult comparisonResult = comparisonTask.get();
187 if (comparisonResult.getResult()) {
188 System.out.println(comparisonResult.getTextualDescription());
190 } catch (InterruptedException|ExecutionException e) {
194 } catch (UnknownHostException |
195 PcapNativeException |
197 TimeoutException ex) {
198 ex.printStackTrace();