RIL: Add compatibility with qcom's DSDS

Devices with radio libraries built against a DSDS-enabled qualcomm
BSP (anything in the last 4 or 5 months, apparently) have a slight
incompatibility in the RIL protocol: it expects the first 4 bytes
of the datastream to be the slot's identification (even if the
device isn't dual-SIM). Absence of those 4 bytes will make the
connection hang.

Change-Id: I9f5821add02e7e5b5286c3b0818cb4a94edcc13c

src/java/com/android/internal/telephony/RIL.java

@@ -521,6 +521,20 @@ class RILReceiver implements Runnable {
                 mSocket = s;
                 Rlog.i(RILJ_LOG_TAG, "Connected to '" + SOCKET_NAME_RIL + "' socket");
 
+                /* Compatibility with qcom's DSDS (Dual SIM) stack */
+                if (needsOldRilFeature("qcomdsds")) {
+                    String str = "SUB1";
+                    byte[] data = str.getBytes();
+                    try {
+                        mSocket.getOutputStream().write(data);
+                        Log.i(LOG_TAG, "Data sent!!");
+                    } catch (IOException ex) {
+                            Log.e(LOG_TAG, "IOException", ex);
+                    } catch (RuntimeException exc) {
+                        Log.e(LOG_TAG, "Uncaught exception ", exc);
+                    }
+                }
+
                 int length = 0;
                 try {
                     InputStream is = mSocket.getInputStream();

src/java/com/android/internal/telephony/dataconnection/DataCallResponse.java

@@ -133,7 +133,7 @@ public SetupResult setLinkProperties(LinkProperties linkProperties,
                         String [] ap = addr.split("/");
                         if (ap.length == 2) {
                             addr = ap[0];
-                            addrPrefixLen = Integer.parseInt(ap[1]);
+                            addrPrefixLen = Integer.parseInt(ap[1].replaceAll("[\\D]",""));
                         } else {
                             addrPrefixLen = 0;
                         }