cgivre commented on a change in pull request #1898: DRILL-7443: Enable PCAP Plugin to Reassemble TCP Streams URL: https://github.com/apache/drill/pull/1898#discussion_r349699326
########## File path: exec/java-exec/src/main/java/org/apache/drill/exec/store/pcap/decoder/TcpHandshake.java ########## @@ -0,0 +1,144 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.drill.exec.store.pcap.decoder; + +/** + * This class is used to record the status of the TCP Handshake. Initially this is used just to determine whether a session is open or closed, but + * future functionality could include SYN flood identification, or other hackery with TCP flags. + */ +public class TcpHandshake { + private boolean isConnected = false; + + private State currentSessionState = State.NONE; + + private long sessionID; + + /** + * Returns true for a correct TCP handshake: SYN|SYNACK|ACK, False if not. + * + * @return boolean true if the session is open, false if not. + */ + public boolean isConnected() { + return isConnected; + } + + /** + * This method returns true if the session is closed properly via FIN -> FIN ACK, false if not. + * + * @return boolean true if the session is closed, false if not. + */ + public boolean isClosed() { + if (currentSessionState == State.CLOSE_WAIT || + currentSessionState == State.FORCED_CLOSED || + currentSessionState == State.CLOSED || + currentSessionState == State.TIME_WAIT || + currentSessionState == State.FIN_WAIT) { + return true; + } else { + return false; + } + } + + public State getCurrentSessionState() { + return currentSessionState; + } + + public void setConnected(long sessionID) { + this.sessionID = sessionID; + currentSessionState = State.OPEN; + isConnected = true; + } + + public void setRst() { + isConnected = false; + currentSessionState = State.FORCED_CLOSED; + } + + public void setFin() { + if (currentSessionState == State.OPEN) { + currentSessionState = State.CLOSE_WAIT; // The next packet should be another FIN packet + } else if (currentSessionState == State.CLOSE_WAIT) { + currentSessionState = State.TIME_WAIT; + } + } + + public void setAck() { + if (currentSessionState == State.SYN) { + currentSessionState = State.SYNACK; + } else if (currentSessionState == State.SYNACK) { + currentSessionState = State.OPEN; + isConnected = true; + } else if (currentSessionState == State.CLOSE_WAIT) { + currentSessionState = State.FIN_WAIT; + } + } + + public void setSyn() { + if (currentSessionState == State.NONE) { + currentSessionState = State.SYN; + } + } + + /** + * This enum variable represents the various states of the TCP Handshake + */ + enum State { + /** + * The NONE state is the initialization state. No session has be established + */ + NONE, + /** + * The OPEN state represents a successfully opened TCP session. It is established in the final step in the TCP + * handshake. + */ + OPEN, + /** + * The CLOSED session represents a closed TCP session. This state occurs after the final ACK of the 4 way close process + */ + CLOSED, + /** + * The CLOSE_WAIT state represents a session in which one party has sent a frame with a FIN flag set. + * At this point resources can be released, however, to fully close the session the other party needs to send a frame + * with an ACK packet. + */ + CLOSE_WAIT, + /** + * Review comment: fixed ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
