testapps/TestRcsApp/aosp_test_rcsclient/src/com/android/libraries/rcs/simpleclient/protocol/sip/SipUtils.java - platform/packages/services/Telephony - Git at Google

 /*
  * Copyright (C) 2020 The Android Open Source Project
  *
  * Licensed 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 com.android.libraries.rcs.simpleclient.protocol.sip;

 import static com.android.libraries.rcs.simpleclient.protocol.sdp.SdpUtils.SDP_CONTENT_SUB_TYPE;
 import static com.android.libraries.rcs.simpleclient.protocol.sdp.SdpUtils.SDP_CONTENT_TYPE;

 import android.text.TextUtils;
 import android.util.Log;

 import androidx.annotation.Nullable;

 import com.android.libraries.rcs.simpleclient.protocol.sdp.SimpleSdpMessage;

 import com.google.common.base.Ascii;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.net.InetAddresses;

 import gov.nist.javax.sip.Utils;
 import gov.nist.javax.sip.address.AddressFactoryImpl;
 import gov.nist.javax.sip.header.ContentType;
 import gov.nist.javax.sip.header.HeaderFactoryImpl;
 import gov.nist.javax.sip.header.Via;
 import gov.nist.javax.sip.header.extensions.SessionExpires;
 import gov.nist.javax.sip.header.ims.PPreferredIdentityHeader;
 import gov.nist.javax.sip.header.ims.PPreferredServiceHeader;
 import gov.nist.javax.sip.header.ims.SecurityVerifyHeader;
 import gov.nist.javax.sip.message.SIPMessage;
 import gov.nist.javax.sip.message.SIPRequest;
 import gov.nist.javax.sip.message.SIPResponse;

 import java.net.Inet6Address;
 import java.text.ParseException;
 import java.util.List;
 import java.util.UUID;

 import javax.sip.InvalidArgumentException;
 import javax.sip.address.AddressFactory;
 import javax.sip.address.SipURI;
 import javax.sip.address.URI;
 import javax.sip.header.ContactHeader;
 import javax.sip.header.Header;
 import javax.sip.header.HeaderFactory;
 import javax.sip.header.ViaHeader;
 import javax.sip.message.Request;
 import javax.sip.message.Response;

 /** Collections of utility functions for SIP */
 public final class SipUtils {
     private static final String TAG = "SipUtils";
     private static final String SUPPORTED_TIMER_TAG = "timer";
     private static final String ICSI_REF_PARAM_NAME = "+g.3gpp.icsi-ref";
     private static final String SIP_INSTANCE_PARAM_NAME = "+sip.instance";
     private static final String CPM_SESSION_FEATURE_TAG_PARAM_VALUE =
             "\"urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.session\"";
     private static final String CPM_SESSION_FEATURE_TAG_FULL_STRING =
             "+g.3gpp.icsi-ref=\"urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.session\"";
     private static final String CPM_SESSION_SERVICE_NAME =
             "urn:urn-7:3gpp-service.ims.icsi.oma.cpm.session";
     private static final String CONTRIBUTION_ID_HEADER_NAME = "Contribution-ID";
     private static final String CONVERSATION_ID_HEADER_NAME = "Conversation-ID";
     private static final String ACCEPT_CONTACT_HEADER_NAME = "Accept-Contact";
     private static final String PANI_HEADER_NAME = "P-Access-Network-Info";
     private static final String PLANI_HEADER_NAME = "P-Last-Access-Network-Info";
     private static final String USER_AGENT_HEADER = "RcsTestClient";

     private static AddressFactory sAddressFactory = new AddressFactoryImpl();
     private static HeaderFactory sHeaderFactory = new HeaderFactoryImpl();

     private SipUtils() {
     }

     /**
      * Try to parse the given uri.
      *
      * @throws IllegalArgumentException in case of parsing error.
      */
     public static URI createUri(String uri) {
         try {
             return sAddressFactory.createURI(uri);
         } catch (ParseException exception) {
             throw new IllegalArgumentException("URI cannot be created", exception);
         }
     }

     /**
      * Create SIP INVITE request for a CPM 1:1 chat.
      *
      * @param configuration  The SipSessionConfiguration instance used for populating SIP headers.
      * @param targetUri      The uri to be targeted.
      * @param conversationId The id to be contained in Conversation-ID header.
      */
     public static SIPRequest buildInvite(
             SipSessionConfiguration configuration,
             String targetUri,
             String conversationId,
             byte[] content)
             throws ParseException {
         String address = configuration.getLocalIpAddress();
         int port = configuration.getLocalPort();
         String transport = configuration.getSipTransport();
         List<String> associatedUris = configuration.getAssociatedUris();
         String preferredUri = Iterables.getFirst(associatedUris,
                 configuration.getPublicUserIdentity());

         SIPRequest request = new SIPRequest();
         request.setMethod(Request.INVITE);

         URI remoteUri = createUri(targetUri);
         request.setRequestURI(remoteUri);
         request.setFrom(
                 sHeaderFactory.createFromHeader(
                         sAddressFactory.createAddress(preferredUri),
                         Utils.getInstance().generateTag()));
         request.setTo(
                 sHeaderFactory.createToHeader(sAddressFactory.createAddress(remoteUri), null));

         ViaHeader viaHeader = null;

         try {
             // Set a default Max-Forwards header.
             request.setMaxForwards(sHeaderFactory.createMaxForwardsHeader(70));
             request.setCSeq(sHeaderFactory.createCSeqHeader(1L, Request.INVITE));
             viaHeader =
                     sHeaderFactory.createViaHeader(
                             address, port, transport, Utils.getInstance().generateBranchId());
             request.setVia(ImmutableList.of(viaHeader));

             // Set a default Session-Expires header.
             SessionExpires sessionExpires = new SessionExpires();
             sessionExpires.setRefresher("uac");
             sessionExpires.setExpires(1800);
             request.setHeader(sessionExpires);

             // Set a Contact header.
             request.setHeader(generateContactHeader(configuration));

             // Set PANI and PLANI if exists
             if (configuration.getPaniHeader() != null) {
                 request.setHeader(
                         sHeaderFactory.createHeader(PANI_HEADER_NAME,
                                 configuration.getPaniHeader()));
             }
             if (configuration.getPlaniHeader() != null) {
                 request.setHeader(
                         sHeaderFactory.createHeader(PLANI_HEADER_NAME,
                                 configuration.getPlaniHeader()));
             }
         } catch (InvalidArgumentException e) {
             // Nothing to do here
             Log.e(TAG, e.getMessage());
         }

         request.setCallId(UUID.randomUUID().toString());
         request.setHeader(sHeaderFactory.createHeader(CONVERSATION_ID_HEADER_NAME, conversationId));
         request.setHeader(
                 sHeaderFactory.createHeader(CONTRIBUTION_ID_HEADER_NAME,
                         UUID.randomUUID().toString()));

         String acceptContact = "*;" + CPM_SESSION_FEATURE_TAG_FULL_STRING;
         request.setHeader(sHeaderFactory.createHeader(ACCEPT_CONTACT_HEADER_NAME, acceptContact));
         request.setHeader(sHeaderFactory.createSupportedHeader(SUPPORTED_TIMER_TAG));
         request.setHeader(sHeaderFactory.createHeader(PPreferredIdentityHeader.NAME, preferredUri));
         request.setHeader(
                 sHeaderFactory.createHeader(PPreferredServiceHeader.NAME,
                         CPM_SESSION_SERVICE_NAME));

         // Set a Security-Verify header if exist.
         String securityVerify = configuration.getSecurityVerifyHeader();
         if (!TextUtils.isEmpty(securityVerify)) {
             request.setHeader(
                     sHeaderFactory.createHeader(SecurityVerifyHeader.NAME, securityVerify));
         }

         // Add Route headers.
         List<String> serviceRoutes = configuration.getServiceRouteHeaders();
         if (!serviceRoutes.isEmpty()) {
             for (String sr : serviceRoutes) {
                 request.addHeader(
                         sHeaderFactory.createRouteHeader(sAddressFactory.createAddress(sr)));
             }
         }

         String userAgent = configuration.getUserAgentHeader();
         userAgent = (userAgent == null) ? USER_AGENT_HEADER : userAgent;
         request.addHeader(sHeaderFactory.createUserAgentHeader(ImmutableList.of(userAgent)));

         request.setMessageContent(SDP_CONTENT_TYPE, SDP_CONTENT_SUB_TYPE, content);

         if (viaHeader != null && Ascii.equalsIgnoreCase("udp", transport)) {
             String newTransport =
                     determineTransportBySize(configuration, request.encodeAsBytes("udp").length);
             if (!Ascii.equalsIgnoreCase(transport, newTransport)) {
                 viaHeader.setTransport(newTransport);
             }
         }

         return request;
     }

     private static ContactHeader generateContactHeader(SipSessionConfiguration configuration)
             throws ParseException {
         String host = configuration.getLocalIpAddress();
         if (isIPv6Address(host)) {
             host = "[" + host + "]";
         }

         String userPart = configuration.getContactUser();
         SipURI uri = sAddressFactory.createSipURI(userPart, host);
         try {
             uri.setPort(configuration.getLocalPort());
             uri.setTransportParam(configuration.getSipTransport());
         } catch (Exception e) {
             // Shouldn't be here.
         }

         ContactHeader contactHeader =
                 sHeaderFactory.createContactHeader(sAddressFactory.createAddress(uri));

         // Add +sip.instance param.
         String sipInstance = "\"<urn:gsma:imei:" + configuration.getImei() + ">\"";
         contactHeader.setParameter(SIP_INSTANCE_PARAM_NAME, sipInstance);

         // Add CPM feature tag.
         uri.setTransportParam(configuration.getSipTransport());
         contactHeader.setParameter(ICSI_REF_PARAM_NAME, CPM_SESSION_FEATURE_TAG_PARAM_VALUE);

         return contactHeader;
     }

     /**
      * Create a SIP BYE request for terminating the chat session.
      *
      * @param invite the initial INVITE request of the chat session.
      */
     public static SIPRequest buildBye(SIPRequest invite) throws ParseException {
         SIPRequest request = new SIPRequest();
         request.setRequestURI(invite.getRequestURI());
         request.setMethod(Request.BYE);
         try {
             long cSeqNumber = invite.getCSeq().getSeqNumber();
             request.setHeader(sHeaderFactory.createCSeqHeader(cSeqNumber, Request.BYE));
         } catch (InvalidArgumentException e) {
             // Nothing to do here
         }

         request.setCallId(invite.getCallId());

         Via via = (Via) invite.getTopmostVia().clone();
         via.removeParameter("branch");
         via.setBranch(Utils.getInstance().generateBranchId());
         request.addHeader(via);
         request.addHeader(
                 sHeaderFactory.createFromHeader(invite.getFrom().getAddress(),
                         invite.getFrom().getTag()));
         request.addHeader(
                 sHeaderFactory.createToHeader(invite.getTo().getAddress(),
                         invite.getTo().getTag()));

         return request;
     }

     /**
      * Create SIP INVITE response for a CPM 1:1 chat.
      *
      * @param configuration The SipSessionConfiguration instance used for populating SIP headers.
      * @param invite        the initial INVITE request of the chat session.
      * @param code          The status code of the response.
      */
     public static SIPResponse buildInviteResponse(
             SipSessionConfiguration configuration,
             SIPRequest invite,
             int code,
             @Nullable SimpleSdpMessage sdp)
             throws ParseException {
         SIPResponse response = invite.createResponse(code);
         if (code == Response.OK) {
             response.setMessageContent(SDP_CONTENT_TYPE, SDP_CONTENT_SUB_TYPE, sdp.encode());
         }
         response.setToTag(Utils.getInstance().generateTag());

         // Set a Contact header.
         response.setHeader(generateContactHeader(configuration));

         // Set Conversation-ID and Contribution-ID
         Header conversationIdHeader = invite.getHeader(CONVERSATION_ID_HEADER_NAME);
         if (conversationIdHeader != null) {
             response.setHeader((Header) conversationIdHeader.clone());
         }
         Header contributionIdHeader = invite.getHeader(CONTRIBUTION_ID_HEADER_NAME);
         if (conversationIdHeader != null) {
             response.setHeader((Header) contributionIdHeader.clone());
         }

         // Set P-Preferred-Identity
         List<String> associatedUris = configuration.getAssociatedUris();
         String preferredUri = Iterables.getFirst(associatedUris,
                 configuration.getPublicUserIdentity());
         response.setHeader(
                 sHeaderFactory.createHeader(PPreferredIdentityHeader.NAME, preferredUri));

         // Set PANI and PLANI if exists
         if (configuration.getPaniHeader() != null) {
             response.setHeader(
                     sHeaderFactory.createHeader(PANI_HEADER_NAME, configuration.getPaniHeader()));
         }
         if (configuration.getPlaniHeader() != null) {
             response.setHeader(
                     sHeaderFactory.createHeader(PLANI_HEADER_NAME, configuration.getPlaniHeader()));
         }
         return response;
     }

     public static boolean isIPv6Address(String address) {
         return InetAddresses.forString(address) instanceof Inet6Address;
     }

     /** Return whether the SIP message has a SDP content or not */
     public static boolean hasSdpContent(SIPMessage message) {
         ContentType contentType = message.getContentTypeHeader();
         return contentType != null
                 && TextUtils.equals(contentType.getContentType(), SDP_CONTENT_TYPE)
                 && TextUtils.equals(contentType.getContentSubType(), SDP_CONTENT_SUB_TYPE);
     }

     private static String determineTransportBySize(SipSessionConfiguration configuration,
             int size) {
         if (size > configuration.getMaxPayloadSizeOnUdp()) {
             return "tcp";
         }
         return "udp";
     }
 }
	/*
	* Copyright (C) 2020 The Android Open Source Project
	*
	* Licensed 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 com.android.libraries.rcs.simpleclient.protocol.sip;

	import static com.android.libraries.rcs.simpleclient.protocol.sdp.SdpUtils.SDP_CONTENT_SUB_TYPE;
	import static com.android.libraries.rcs.simpleclient.protocol.sdp.SdpUtils.SDP_CONTENT_TYPE;

	import android.text.TextUtils;
	import android.util.Log;

	import androidx.annotation.Nullable;

	import com.android.libraries.rcs.simpleclient.protocol.sdp.SimpleSdpMessage;

	import com.google.common.base.Ascii;
	import com.google.common.collect.ImmutableList;
	import com.google.common.collect.Iterables;
	import com.google.common.net.InetAddresses;

	import gov.nist.javax.sip.Utils;
	import gov.nist.javax.sip.address.AddressFactoryImpl;
	import gov.nist.javax.sip.header.ContentType;
	import gov.nist.javax.sip.header.HeaderFactoryImpl;
	import gov.nist.javax.sip.header.Via;
	import gov.nist.javax.sip.header.extensions.SessionExpires;
	import gov.nist.javax.sip.header.ims.PPreferredIdentityHeader;
	import gov.nist.javax.sip.header.ims.PPreferredServiceHeader;
	import gov.nist.javax.sip.header.ims.SecurityVerifyHeader;
	import gov.nist.javax.sip.message.SIPMessage;
	import gov.nist.javax.sip.message.SIPRequest;
	import gov.nist.javax.sip.message.SIPResponse;

	import java.net.Inet6Address;
	import java.text.ParseException;
	import java.util.List;
	import java.util.UUID;

	import javax.sip.InvalidArgumentException;
	import javax.sip.address.AddressFactory;
	import javax.sip.address.SipURI;
	import javax.sip.address.URI;
	import javax.sip.header.ContactHeader;
	import javax.sip.header.Header;
	import javax.sip.header.HeaderFactory;
	import javax.sip.header.ViaHeader;
	import javax.sip.message.Request;
	import javax.sip.message.Response;

	/** Collections of utility functions for SIP */
	public final class SipUtils {
	private static final String TAG = "SipUtils";
	private static final String SUPPORTED_TIMER_TAG = "timer";
	private static final String ICSI_REF_PARAM_NAME = "+g.3gpp.icsi-ref";
	private static final String SIP_INSTANCE_PARAM_NAME = "+sip.instance";
	private static final String CPM_SESSION_FEATURE_TAG_PARAM_VALUE =
	"\"urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.session\"";
	private static final String CPM_SESSION_FEATURE_TAG_FULL_STRING =
	"+g.3gpp.icsi-ref=\"urn%3Aurn-7%3A3gpp-service.ims.icsi.oma.cpm.session\"";
	private static final String CPM_SESSION_SERVICE_NAME =
	"urn:urn-7:3gpp-service.ims.icsi.oma.cpm.session";
	private static final String CONTRIBUTION_ID_HEADER_NAME = "Contribution-ID";
	private static final String CONVERSATION_ID_HEADER_NAME = "Conversation-ID";
	private static final String ACCEPT_CONTACT_HEADER_NAME = "Accept-Contact";
	private static final String PANI_HEADER_NAME = "P-Access-Network-Info";
	private static final String PLANI_HEADER_NAME = "P-Last-Access-Network-Info";
	private static final String USER_AGENT_HEADER = "RcsTestClient";

	private static AddressFactory sAddressFactory = new AddressFactoryImpl();
	private static HeaderFactory sHeaderFactory = new HeaderFactoryImpl();

	private SipUtils() {
	}

	/**
	* Try to parse the given uri.
	*
	* @throws IllegalArgumentException in case of parsing error.
	*/
	public static URI createUri(String uri) {
	try {
	return sAddressFactory.createURI(uri);
	} catch (ParseException exception) {
	throw new IllegalArgumentException("URI cannot be created", exception);
	}
	}

	/**
	* Create SIP INVITE request for a CPM 1:1 chat.
	*
	* @param configuration The SipSessionConfiguration instance used for populating SIP headers.
	* @param targetUri The uri to be targeted.
	* @param conversationId The id to be contained in Conversation-ID header.
	*/
	public static SIPRequest buildInvite(
	SipSessionConfiguration configuration,
	String targetUri,
	String conversationId,
	byte[] content)
	throws ParseException {
	String address = configuration.getLocalIpAddress();
	int port = configuration.getLocalPort();
	String transport = configuration.getSipTransport();
	List<String> associatedUris = configuration.getAssociatedUris();
	String preferredUri = Iterables.getFirst(associatedUris,
	configuration.getPublicUserIdentity());

	SIPRequest request = new SIPRequest();
	request.setMethod(Request.INVITE);

	URI remoteUri = createUri(targetUri);
	request.setRequestURI(remoteUri);
	request.setFrom(
	sHeaderFactory.createFromHeader(
	sAddressFactory.createAddress(preferredUri),
	Utils.getInstance().generateTag()));
	request.setTo(
	sHeaderFactory.createToHeader(sAddressFactory.createAddress(remoteUri), null));

	ViaHeader viaHeader = null;

	try {
	// Set a default Max-Forwards header.
	request.setMaxForwards(sHeaderFactory.createMaxForwardsHeader(70));
	request.setCSeq(sHeaderFactory.createCSeqHeader(1L, Request.INVITE));
	viaHeader =
	sHeaderFactory.createViaHeader(
	address, port, transport, Utils.getInstance().generateBranchId());
	request.setVia(ImmutableList.of(viaHeader));

	// Set a default Session-Expires header.
	SessionExpires sessionExpires = new SessionExpires();
	sessionExpires.setRefresher("uac");
	sessionExpires.setExpires(1800);
	request.setHeader(sessionExpires);

	// Set a Contact header.
	request.setHeader(generateContactHeader(configuration));

	// Set PANI and PLANI if exists
	if (configuration.getPaniHeader() != null) {
	request.setHeader(
	sHeaderFactory.createHeader(PANI_HEADER_NAME,
	configuration.getPaniHeader()));
	}
	if (configuration.getPlaniHeader() != null) {
	request.setHeader(
	sHeaderFactory.createHeader(PLANI_HEADER_NAME,
	configuration.getPlaniHeader()));
	}
	} catch (InvalidArgumentException e) {
	// Nothing to do here
	Log.e(TAG, e.getMessage());
	}

	request.setCallId(UUID.randomUUID().toString());
	request.setHeader(sHeaderFactory.createHeader(CONVERSATION_ID_HEADER_NAME, conversationId));
	request.setHeader(
	sHeaderFactory.createHeader(CONTRIBUTION_ID_HEADER_NAME,
	UUID.randomUUID().toString()));

	String acceptContact = "*;" + CPM_SESSION_FEATURE_TAG_FULL_STRING;
	request.setHeader(sHeaderFactory.createHeader(ACCEPT_CONTACT_HEADER_NAME, acceptContact));
	request.setHeader(sHeaderFactory.createSupportedHeader(SUPPORTED_TIMER_TAG));
	request.setHeader(sHeaderFactory.createHeader(PPreferredIdentityHeader.NAME, preferredUri));
	request.setHeader(
	sHeaderFactory.createHeader(PPreferredServiceHeader.NAME,
	CPM_SESSION_SERVICE_NAME));

	// Set a Security-Verify header if exist.
	String securityVerify = configuration.getSecurityVerifyHeader();
	if (!TextUtils.isEmpty(securityVerify)) {
	request.setHeader(
	sHeaderFactory.createHeader(SecurityVerifyHeader.NAME, securityVerify));
	}

	// Add Route headers.
	List<String> serviceRoutes = configuration.getServiceRouteHeaders();
	if (!serviceRoutes.isEmpty()) {
	for (String sr : serviceRoutes) {
	request.addHeader(
	sHeaderFactory.createRouteHeader(sAddressFactory.createAddress(sr)));
	}
	}

	String userAgent = configuration.getUserAgentHeader();
	userAgent = (userAgent == null) ? USER_AGENT_HEADER : userAgent;
	request.addHeader(sHeaderFactory.createUserAgentHeader(ImmutableList.of(userAgent)));

	request.setMessageContent(SDP_CONTENT_TYPE, SDP_CONTENT_SUB_TYPE, content);

	if (viaHeader != null && Ascii.equalsIgnoreCase("udp", transport)) {
	String newTransport =
	determineTransportBySize(configuration, request.encodeAsBytes("udp").length);
	if (!Ascii.equalsIgnoreCase(transport, newTransport)) {
	viaHeader.setTransport(newTransport);
	}
	}

	return request;
	}

	private static ContactHeader generateContactHeader(SipSessionConfiguration configuration)
	throws ParseException {
	String host = configuration.getLocalIpAddress();
	if (isIPv6Address(host)) {
	host = "[" + host + "]";
	}

	String userPart = configuration.getContactUser();
	SipURI uri = sAddressFactory.createSipURI(userPart, host);
	try {
	uri.setPort(configuration.getLocalPort());
	uri.setTransportParam(configuration.getSipTransport());
	} catch (Exception e) {
	// Shouldn't be here.
	}

	ContactHeader contactHeader =
	sHeaderFactory.createContactHeader(sAddressFactory.createAddress(uri));

	// Add +sip.instance param.
	String sipInstance = "\"<urn:gsma:imei:" + configuration.getImei() + ">\"";
	contactHeader.setParameter(SIP_INSTANCE_PARAM_NAME, sipInstance);

	// Add CPM feature tag.
	uri.setTransportParam(configuration.getSipTransport());
	contactHeader.setParameter(ICSI_REF_PARAM_NAME, CPM_SESSION_FEATURE_TAG_PARAM_VALUE);

	return contactHeader;
	}

	/**
	* Create a SIP BYE request for terminating the chat session.
	*
	* @param invite the initial INVITE request of the chat session.
	*/
	public static SIPRequest buildBye(SIPRequest invite) throws ParseException {
	SIPRequest request = new SIPRequest();
	request.setRequestURI(invite.getRequestURI());
	request.setMethod(Request.BYE);
	try {
	long cSeqNumber = invite.getCSeq().getSeqNumber();
	request.setHeader(sHeaderFactory.createCSeqHeader(cSeqNumber, Request.BYE));
	} catch (InvalidArgumentException e) {
	// Nothing to do here
	}

	request.setCallId(invite.getCallId());

	Via via = (Via) invite.getTopmostVia().clone();
	via.removeParameter("branch");
	via.setBranch(Utils.getInstance().generateBranchId());
	request.addHeader(via);
	request.addHeader(
	sHeaderFactory.createFromHeader(invite.getFrom().getAddress(),
	invite.getFrom().getTag()));
	request.addHeader(
	sHeaderFactory.createToHeader(invite.getTo().getAddress(),
	invite.getTo().getTag()));

	return request;
	}

	/**
	* Create SIP INVITE response for a CPM 1:1 chat.
	*
	* @param configuration The SipSessionConfiguration instance used for populating SIP headers.
	* @param invite the initial INVITE request of the chat session.
	* @param code The status code of the response.
	*/
	public static SIPResponse buildInviteResponse(
	SipSessionConfiguration configuration,
	SIPRequest invite,
	int code,
	@Nullable SimpleSdpMessage sdp)
	throws ParseException {
	SIPResponse response = invite.createResponse(code);
	if (code == Response.OK) {
	response.setMessageContent(SDP_CONTENT_TYPE, SDP_CONTENT_SUB_TYPE, sdp.encode());
	}
	response.setToTag(Utils.getInstance().generateTag());

	// Set a Contact header.
	response.setHeader(generateContactHeader(configuration));

	// Set Conversation-ID and Contribution-ID
	Header conversationIdHeader = invite.getHeader(CONVERSATION_ID_HEADER_NAME);
	if (conversationIdHeader != null) {
	response.setHeader((Header) conversationIdHeader.clone());
	}
	Header contributionIdHeader = invite.getHeader(CONTRIBUTION_ID_HEADER_NAME);
	if (conversationIdHeader != null) {
	response.setHeader((Header) contributionIdHeader.clone());
	}

	// Set P-Preferred-Identity
	List<String> associatedUris = configuration.getAssociatedUris();
	String preferredUri = Iterables.getFirst(associatedUris,
	configuration.getPublicUserIdentity());
	response.setHeader(
	sHeaderFactory.createHeader(PPreferredIdentityHeader.NAME, preferredUri));

	// Set PANI and PLANI if exists
	if (configuration.getPaniHeader() != null) {
	response.setHeader(
	sHeaderFactory.createHeader(PANI_HEADER_NAME, configuration.getPaniHeader()));
	}
	if (configuration.getPlaniHeader() != null) {
	response.setHeader(
	sHeaderFactory.createHeader(PLANI_HEADER_NAME, configuration.getPlaniHeader()));
	}
	return response;
	}

	public static boolean isIPv6Address(String address) {
	return InetAddresses.forString(address) instanceof Inet6Address;
	}

	/** Return whether the SIP message has a SDP content or not */
	public static boolean hasSdpContent(SIPMessage message) {
	ContentType contentType = message.getContentTypeHeader();
	return contentType != null
	&& TextUtils.equals(contentType.getContentType(), SDP_CONTENT_TYPE)
	&& TextUtils.equals(contentType.getContentSubType(), SDP_CONTENT_SUB_TYPE);
	}

	private static String determineTransportBySize(SipSessionConfiguration configuration,
	int size) {
	if (size > configuration.getMaxPayloadSizeOnUdp()) {
	return "tcp";
	}
	return "udp";
	}
	}