Start keepalive process for the caller of a SIP call

so that the callee can send signals (on-hold or bye) back to the caller.
Without the keepalive, the NAT port for the caller will be timed out during the
call. And the signals will be dropped by the NAT device.

Change-Id: I21848d73469045b2ed9e7281556ab184c594c362

1 files changed, 27 insertions, 3 deletions

diff --git a/voip/java/com/android/server/sip/SipSessionGroup.java b/voip/java/com/android/server/sip/SipSessionGroup.java
index 481e306..6304369 100644
--- a/voip/java/com/android/server/sip/SipSessionGroup.java
+++ b/voip/java/com/android/server/sip/SipSessionGroup.java
@@ -93,6 +93,7 @@ class SipSessionGroup implements SipListener {
     private static final int EXPIRY_TIME = 3600; // in seconds
     private static final int CANCEL_CALL_TIMER = 3; // in seconds
     private static final int KEEPALIVE_TIMEOUT = 3; // in seconds
+    private static final int INCALL_KEEPALIVE_INTERVAL = 10; // in seconds
     private static final long WAKE_LOCK_HOLDING_TIME = 500; // in milliseconds
 
     private static final EventObject DEREGISTER = new EventObject("Deregister");
@@ -477,6 +478,8 @@ class SipSessionGroup implements SipListener {
 
         private KeepAliveProcess mKeepAliveProcess;
 
+        private SipSessionImpl mKeepAliveSession;
+
         // lightweight timer
         class SessionTimer {
             private boolean mRunning = true;
@@ -545,6 +548,11 @@ class SipSessionGroup implements SipListener {
             mClientTransaction = null;
 
             cancelSessionTimer();
+
+            if (mKeepAliveSession != null) {
+                mKeepAliveSession.stopKeepAliveProcess();
+                mKeepAliveSession = null;
+            }
         }
 
         public boolean isInCall() {
@@ -999,7 +1007,7 @@ class SipSessionGroup implements SipListener {
                 throws SipException {
             // expect ACK, CANCEL request
             if (isRequestEvent(Request.ACK, evt)) {
-                establishCall();
+                establishCall(false);
                 return true;
             } else if (isRequestEvent(Request.CANCEL, evt)) {
                 // http://tools.ietf.org/html/rfc3261#section-9.2
@@ -1031,7 +1039,7 @@ class SipSessionGroup implements SipListener {
                 case Response.OK:
                     mSipHelper.sendInviteAck(event, mDialog);
                     mPeerSessionDescription = extractContent(response);
-                    establishCall();
+                    establishCall(true);
                     return true;
                 case Response.UNAUTHORIZED:
                 case Response.PROXY_AUTHENTICATION_REQUIRED:
@@ -1163,10 +1171,26 @@ class SipSessionGroup implements SipListener {
                     response.getStatusCode());
         }
 
-        private void establishCall() {
+        private void enableKeepAlive() {
+            if (mKeepAliveSession != null) {
+                mKeepAliveSession.stopKeepAliveProcess();
+            } else {
+                mKeepAliveSession = duplicate();
+            }
+            try {
+                mKeepAliveSession.startKeepAliveProcess(
+                        INCALL_KEEPALIVE_INTERVAL, mPeerProfile, null);
+            } catch (SipException e) {
+                Log.w(TAG, "keepalive cannot be enabled; ignored", e);
+                mKeepAliveSession.stopKeepAliveProcess();
+            }
+        }
+
+        private void establishCall(boolean enableKeepAlive) {
             mState = SipSession.State.IN_CALL;
             mInCall = true;
             cancelSessionTimer();
+            if (enableKeepAlive) enableKeepAlive();
             mProxy.onCallEstablished(this, mPeerSessionDescription);
         }