Add ALPN interface

include/polarssl/config.h

@@ -860,6 +860,19 @@
  */
 #define POLARSSL_SSL_PROTO_TLS1_2
 
+/**
+ * \def POLARSSL_SSL_ALPN
+ *
+ * Enable support for Application Layer Protocol Negotiation.
+ * draft-ietf-tls-applayerprotoneg-05
+ *
+ * This is disabled by default in the 1.3.x line since it breaks ABI
+ * compatibility.
+ *
+ * Uncomment this macro to enable support for ALPN.
+ */
+#define POLARSSL_SSL_ALPN
+
 /**
  * \def POLARSSL_SSL_SESSION_TICKETS
  *

include/polarssl/ssl.h

@@ -762,6 +762,14 @@ struct _ssl_context
     size_t         hostname_len;
 #endif
 
+#if defined(POLARSSL_SSL_ALPN)
+    /*
+     * ALPN extension
+     */
+    const char **alpn_list;     /*!<  ordered list of supported protocols   */
+    const char *alpn_chosen;    /*!<  negotiated protocol                   */
+#endif
+
     /*
      * Secure renegotiation
      */
@@ -1232,6 +1240,28 @@ void ssl_set_sni( ssl_context *ssl,
                   void *p_sni );
 #endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */
 
+#if defined(POLARSSL_SSL_ALPN)
+/**
+ * \brief          Set the supported Application Layer Protocols.
+ *
+ * \param ssl      SSL context
+ * \param protos   NULL-terminated list of supported protocols,
+ *                 in decreasing preference order.
+ */
+void ssl_set_alpn_protocols( ssl_context *ssl, const char **protos );
+
+/**
+ * \brief          Get the name of the negotiated Application Layer Protocol.
+ *                 This function should be called after the handshake is
+ *                 completed.
+ *
+ * \param ssl      SSL context
+ *
+ * \return         Protcol name, or NULL if no protocol was negotiated.
+ */
+const char *ssl_get_alpn_protocol( const ssl_context *ssl );
+#endif /* POLARSSL_SSL_ALPN */
+
 /**
  * \brief          Set the maximum supported version sent from the client side
  *                 and/or accepted at the server side

library/ssl_tls.c

@@ -3520,6 +3520,10 @@ int ssl_session_reset( ssl_context *ssl )
         ssl->session = NULL;
     }
 
+#if defined(POLARSSL_SSL_ALPN)
+    ssl->alpn_chosen = NULL;
+#endif
+
     if( ( ret = ssl_handshake_init( ssl ) ) != 0 )
         return( ret );
 
@@ -3914,6 +3918,18 @@ void ssl_set_sni( ssl_context *ssl,
 }
 #endif /* POLARSSL_SSL_SERVER_NAME_INDICATION */
 
+#if defined(POLARSSL_SSL_ALPN)
+void ssl_set_alpn_protocols( ssl_context *ssl, const char **protos )
+{
+    ssl->alpn_list = protos;
+}
+
+const char *ssl_get_alpn_protocol( const ssl_context *ssl )
+{
+    return ssl->alpn_chosen;
+}
+#endif /* POLARSSL_SSL_ALPN */
+
 void ssl_set_max_version( ssl_context *ssl, int major, int minor )
 {
     if( major >= SSL_MIN_MAJOR_VERSION && major <= SSL_MAX_MAJOR_VERSION &&