From 8f06296efe2460dd6166e65d0d5fcd187c5163d6 Mon Sep 17 00:00:00 2001
From: Subodh Iyengar <subodh@fb.com>
Date: Tue, 3 Nov 2015 21:38:07 -0800
Subject: [PATCH] Add ability to get application protocol from
 AsyncTransportWrapper

Summary: Allows AsyncTransportWrapper's to supply the underlying application
protocol being used, for example using NPN for SSL or some other
generic protocol indication mechanism.

Reviewed By: ranjeeth

Differential Revision: D2614179

fb-gh-sync-id: 2079782bb7d44f898fb14c7df15077209b022424
---
 folly/io/async/AsyncSSLSocket.cpp | 9 +++++++++
 folly/io/async/AsyncSSLSocket.h   | 1 +
 folly/io/async/AsyncTransport.h   | 9 +++++++++
 3 files changed, 19 insertions(+)

diff --git a/folly/io/async/AsyncSSLSocket.cpp b/folly/io/async/AsyncSSLSocket.cpp
index e34df564..101c1fc6 100644
--- a/folly/io/async/AsyncSSLSocket.cpp
+++ b/folly/io/async/AsyncSSLSocket.cpp
@@ -402,6 +402,15 @@ bool AsyncSSLSocket::connecting() const {
                                      sslState_ == STATE_CONNECTING))));
 }
 
+std::string AsyncSSLSocket::getApplicationProtocol() noexcept {
+  const unsigned char* protoName = nullptr;
+  unsigned protoLength;
+  if (getSelectedNextProtocolNoThrow(&protoName, &protoLength)) {
+    return std::string(reinterpret_cast<const char*>(protoName), protoLength);
+  }
+  return "";
+}
+
 bool AsyncSSLSocket::isEorTrackingEnabled() const {
   const BIO *wb = SSL_get_wbio(ssl_);
   return wb && wb->method == &eorAwareBioMethod;
diff --git a/folly/io/async/AsyncSSLSocket.h b/folly/io/async/AsyncSSLSocket.h
index 91d7849c..b70fd283 100644
--- a/folly/io/async/AsyncSSLSocket.h
+++ b/folly/io/async/AsyncSSLSocket.h
@@ -273,6 +273,7 @@ class AsyncSSLSocket : public virtual AsyncSocket {
   virtual void shutdownWriteNow() override;
   virtual bool good() const override;
   virtual bool connecting() const override;
+  virtual std::string getApplicationProtocol() noexcept override;
 
   bool isEorTrackingEnabled() const override;
   virtual void setEorTracking(bool track) override;
diff --git a/folly/io/async/AsyncTransport.h b/folly/io/async/AsyncTransport.h
index 26cafbff..13bc6c94 100644
--- a/folly/io/async/AsyncTransport.h
+++ b/folly/io/async/AsyncTransport.h
@@ -533,6 +533,15 @@ class AsyncTransportWrapper : virtual public AsyncTransport,
   virtual AsyncTransportWrapper* getWrappedTransport() {
     return nullptr;
   }
+
+  /**
+   * Return the application protocol being used by the underlying transport
+   * protocol. This is useful for transports which are used to tunnel other
+   * protocols.
+   */
+  virtual std::string getApplicationProtocol() noexcept {
+    return "";
+  }
 };
 
 } // folly
-- 
2.34.1