DO NOT MERGE: Respond to RTSP server->client requests.

Even if it's just to tell them that we don't support any (this is optional).

Change-Id: Iee50b4020f28a47dfbe5d56f1732fe044b3b3655
related-to-bug: 3353752

media/libstagefright/rtsp/ARTSPConnection.cpp

@@ -545,6 +545,10 @@ sp<ABuffer> ARTSPConnection::receiveBinaryData() {
     return buffer;
 }
 
+static bool IsRTSPVersion(const AString &s) {
+    return s == "RTSP/1.0";
+}
+
 bool ARTSPConnection::receiveRTSPReponse() {
     AString statusLine;
 
@@ -584,6 +588,19 @@ bool ARTSPConnection::receiveRTSPReponse() {
         return false;
     }
 
+    bool isRequest = false;
+
+    if (!IsRTSPVersion(AString(response->mStatusLine, 0, space1))) {
+        CHECK(IsRTSPVersion(
+                    AString(
+                        response->mStatusLine,
+                        space2 + 1,
+                        response->mStatusLine.size() - space2 - 1)));
+
+        isRequest = true;
+
+        response->mStatusCode = 0;
+    } else {
         AString statusCodeStr(
                 response->mStatusLine, space1 + 1, space2 - space1 - 1);
 
@@ -592,6 +609,7 @@ bool ARTSPConnection::receiveRTSPReponse() {
                 || response->mStatusCode < 100 || response->mStatusCode > 999) {
             return false;
         }
+    }
 
     AString line;
     for (;;) {
@@ -680,7 +698,63 @@ bool ARTSPConnection::receiveRTSPReponse() {
         }
     }
 
-    return notifyResponseListener(response);
+    return isRequest
+        ? handleServerRequest(response)
+        : notifyResponseListener(response);
+}
+
+bool ARTSPConnection::handleServerRequest(const sp<ARTSPResponse> &request) {
+    // Implementation of server->client requests is optional for all methods
+    // but we do need to respond, even if it's just to say that we don't
+    // support the method.
+
+    ssize_t space1 = request->mStatusLine.find(" ");
+    CHECK_GE(space1, 0);
+
+    AString response;
+    response.append("RTSP/1.0 501 Not Implemented\r\n");
+
+    ssize_t i = request->mHeaders.indexOfKey("cseq");
+
+    if (i >= 0) {
+        AString value = request->mHeaders.valueAt(i);
+
+        unsigned long cseq;
+        if (!ParseSingleUnsignedLong(value.c_str(), &cseq)) {
+            return false;
+        }
+
+        response.append("CSeq: ");
+        response.append(cseq);
+        response.append("\r\n");
+    }
+
+    response.append("\r\n");
+
+    size_t numBytesSent = 0;
+    while (numBytesSent < response.size()) {
+        ssize_t n =
+            send(mSocket, response.c_str() + numBytesSent,
+                 response.size() - numBytesSent, 0);
+
+        if (n == 0) {
+            // Server closed the connection.
+            LOGE("Server unexpectedly closed the connection.");
+
+            return false;
+        } else if (n < 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+
+            LOGE("Error sending rtsp response.");
+            return false;
+        }
+
+        numBytesSent += (size_t)n;
+    }
+
+    return true;
 }
 
 // static

media/libstagefright/rtsp/ARTSPConnection.h

@@ -109,6 +109,8 @@ private:
     status_t findPendingRequest(
             const sp<ARTSPResponse> &response, ssize_t *index) const;
 
+    bool handleServerRequest(const sp<ARTSPResponse> &request);
+
     static bool ParseSingleUnsignedLong(
             const char *from, unsigned long *x);