From 3cccf87d807b87be0a178644e91e29394fd2e524 Mon Sep 17 00:00:00 2001
From: Brad Ebinger <breadley@google.com>
Date: Tue, 6 Apr 2021 18:55:27 +0000
Subject: [PATCH] Expose parsing util methods for telephony validation

Bug: 173828358
Test: atest TeleServiceTests
Change-Id: I271a36bcecb332c30f04e7fb22c45098384bc634
---
 .../telephony/SipMessageParsingUtils.java      | 18 ++++++++++++++++--
 .../telephony/ims/SipDelegateManager.java      |  9 +++++++--
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/telephony/common/com/android/internal/telephony/SipMessageParsingUtils.java b/telephony/common/com/android/internal/telephony/SipMessageParsingUtils.java
index 179248dd2cf98..33b0bbd230867 100644
--- a/telephony/common/com/android/internal/telephony/SipMessageParsingUtils.java
+++ b/telephony/common/com/android/internal/telephony/SipMessageParsingUtils.java
@@ -80,6 +80,15 @@ public class SipMessageParsingUtils {
         return verifySipRequest(splitLine);
     }
 
+    /**
+     * @return true if the SIP message start line is considered a response.
+     */
+    public static boolean isSipResponse(String startLine) {
+        String[] splitLine = splitStartLineAndVerify(startLine);
+        if (splitLine == null) return false;
+        return verifySipResponse(splitLine);
+    }
+
     /**
      * Return the via branch parameter, which is used to identify the transaction ID (request and
      * response pair) in a SIP transaction.
@@ -140,7 +149,12 @@ public class SipMessageParsingUtils {
         return !headers.isEmpty() ? headers.get(0).second : null;
     }
 
-    private static String[] splitStartLineAndVerify(String startLine) {
+    /**
+     * Validate that the start line is correct and split into its three segments.
+     * @param startLine The start line to verify and split.
+     * @return The split start line, which will always have three segments.
+     */
+    public static String[] splitStartLineAndVerify(String startLine) {
         String[] splitLine = startLine.split(" ");
         if (isStartLineMalformed(splitLine)) return null;
         return splitLine;
@@ -184,7 +198,7 @@ public class SipMessageParsingUtils {
      *                           (This is internally an equalsIgnoreMatch comparison).
      * @return the matched header keys and values.
      */
-    private static List<Pair<String, String>> parseHeaders(String headerString,
+    public static List<Pair<String, String>> parseHeaders(String headerString,
             boolean stopAtFirstMatch, String... matchingHeaderKeys) {
         // Ensure there is no leading whitespace
         headerString = removeLeadingWhitespace(headerString);
diff --git a/telephony/java/android/telephony/ims/SipDelegateManager.java b/telephony/java/android/telephony/ims/SipDelegateManager.java
index 625364b1bbb0d..9258e4445d882 100644
--- a/telephony/java/android/telephony/ims/SipDelegateManager.java
+++ b/telephony/java/android/telephony/ims/SipDelegateManager.java
@@ -80,13 +80,18 @@ public class SipDelegateManager {
     public static final int MESSAGE_FAILURE_REASON_DELEGATE_CLOSED = 2;
 
     /**
-     * The SIP message has an invalid start line and the message can not be sent.
+     * The SIP message has an invalid start line and the message can not be sent or the start line
+     * failed validation due to the request containing a restricted SIP request method.
+     * {@link SipDelegateConnection}s can not send SIP requests for the methods: REGISTER, PUBLISH,
+     * or OPTIONS.
      */
     public static final int MESSAGE_FAILURE_REASON_INVALID_START_LINE = 3;
 
     /**
      * One or more of the header fields in the header section of the outgoing SIP message is invalid
-     * and the SIP message can not be sent.
+     * or contains a restricted header value and the SIP message can not be sent.
+     * {@link SipDelegateConnection}s can not send SIP SUBSCRIBE requests for the "Event" header
+     * value of "presence".
      */
     public static final int MESSAGE_FAILURE_REASON_INVALID_HEADER_FIELDS = 4;