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- package de.tudarmstadt.informatik.hostage.protocol;
- import java.util.ArrayList;
- import java.util.List;
- import de.tudarmstadt.informatik.hostage.wrapper.Packet;
- /**
- * SIP protocol. Implementation of RFC document 3261 It can handle the
- * following requests: REGISTER, INVITE, ACK, BYE. For all other requests
- * '400 Bad Request' will be replied.
- * @author Wulf Pfeiffer
- */
- public class SIP implements Protocol {
-
- private enum STATE {
- NONE, CLOSED
- }
-
- private STATE state = STATE.NONE;
-
- private static final String VERSION = "SIP/2.0";
- private static final String REGISTER = "REGISTER";
- private static final String INVITE = "INVITE";
- private static final String ACK= "ACK";
- private static final String BYE = "BYE";
- private static final String STATUS_CODE_200 = "200 OK";
- private static final String STATUS_CODE_400 = "400 Bad Request";
- private static final String STATUS_CODE_505 = "505 Version Not Supported";
-
- private String header;
- private String sdpPayload;
- @Override
- public int getPort() {
- return 5060;
- }
- @Override
- public boolean isClosed() {
- return (state == STATE.CLOSED);
- }
- @Override
- public boolean isSecure() {
- return false;
- }
- @Override
- public List<Packet> processMessage(Packet requestPacket) {
- String request = null;
- if (requestPacket != null) {
- request = requestPacket.toString();
- }
- List<Packet> responsePackets = new ArrayList<Packet>();
- String[] lines = request.split("\r\n");
- extractLines(lines);
-
- if(!lines[0].contains(VERSION)) {
- responsePackets.add(getVersionNotSupportedResponse());
- return responsePackets;
- } else if(lines[0].contains(REGISTER)) {
- responsePackets.add(getOkResponse());
- } else if(lines[0].contains(INVITE)) {
- responsePackets.add(getOkResponseWithSDP());
- } else if(lines[0].contains(BYE)) {
- responsePackets.add(getOkResponse());
- state = STATE.CLOSED;
- } else if(lines[0].contains(ACK)) {
- //nothing to do here
- } else {
- responsePackets.add(getBadRequestResponse());
- }
-
- return responsePackets;
- }
- @Override
- public TALK_FIRST whoTalksFirst() {
- return TALK_FIRST.CLIENT;
- }
-
- @Override
- public String toString() {
- return "SIP";
- }
-
- private void extractLines(String[] lines) {
- header = "";
- sdpPayload = "";
- StringBuffer sbHeader = new StringBuffer();
- StringBuffer sbSdp = new StringBuffer();
- boolean recordHeader = false;
- boolean recordSdp = false;
- for (String line : lines) {
- if (line.startsWith("Via:")) {
- recordHeader = true;
- } else if (line.startsWith("Max-Forwards")) {
- recordHeader = false;
- header = sbHeader.toString();
- } else if(line.startsWith("v=")) {
- recordSdp = true;
- } else if(line.startsWith("a=")) {
- sbSdp.append(line + "\r\n");
- sdpPayload = sbSdp.toString();
- break;
- }
- if(recordHeader) {
- sbHeader.append(line + "\r\n");
- } else if(recordSdp) {
- sbSdp.append(line + "\r\n");
- }
- }
- }
-
- private Packet getOkResponseWithSDP() {
- StringBuffer sb = new StringBuffer();
- sb.append(VERSION + " " + STATUS_CODE_200 + "\r\n");
- sb.append(header);
- sb.append("Content-Type: application/sdp\r\n");
- sb.append("Content-Length: " + sdpPayload.length() + "\r\n");
- sb.append("\r\n");
- sb.append(sdpPayload);
- return new Packet(sb.toString(), toString());
- }
-
- private Packet getOkResponse() {
- StringBuffer sb = new StringBuffer();
- sb.append(VERSION + " " + STATUS_CODE_200 + "\r\n");
- sb.append(header);
- sb.append("Content-Length: 0\r\n");
-
- return new Packet(sb.toString(), toString());
- }
-
- private Packet getBadRequestResponse() {
- StringBuffer sb = new StringBuffer();
- sb.append(VERSION + " " + STATUS_CODE_400 + "\r\n");
- sb.append(header);
- sb.append("Content-Length: 0\r\n");
-
- return new Packet(sb.toString(), toString());
- }
-
- private Packet getVersionNotSupportedResponse() {
- StringBuffer sb = new StringBuffer();
- sb.append(VERSION + " " + STATUS_CODE_505 + "\r\n");
- sb.append(header);
- sb.append("Content-Length: 0\r\n");
-
- return new Packet(sb.toString(), toString());
- }
- }
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