shrpx: Use SNI TLS extension in client mode

src/shrpx_spdy_session.cc

@@ -254,6 +254,14 @@ int SpdySession::initiate_connection()
                << ERR_error_string(ERR_get_error(), NULL);
     return -1;
   }
+
+  if(!ssl::numeric_host(get_config()->downstream_host)) {
+    // TLS extensions: SNI. There is no documentation about the return
+    // code for this function (actually this is macro wrapping SSL_ctrl
+    // at the time of this writing).
+    SSL_set_tlsext_host_name(ssl_, get_config()->downstream_host);
+  }
+
   bev_ = bufferevent_openssl_socket_new(evbase_, -1, ssl_,
                                         BUFFEREVENT_SSL_CONNECTING,
                                         BEV_OPT_DEFER_CALLBACKS);

src/shrpx_ssl.cc

@@ -250,7 +250,6 @@ ClientHandler* accept_ssl_connection(event_base *evbase, SSL_CTX *ssl_ctx,
   }
 }
 
-namespace {
 bool numeric_host(const char *hostname)
 {
   struct addrinfo hints;
@@ -264,7 +263,6 @@ bool numeric_host(const char *hostname)
   freeaddrinfo(res);
   return true;
 }
-} // namespace
 
 namespace {
 bool tls_hostname_match(const char *pattern, const char *hostname)

src/shrpx_ssl.h

@@ -46,6 +46,8 @@ ClientHandler* accept_ssl_connection(event_base *evbase, SSL_CTX *ssl_ctx,
                                      evutil_socket_t fd,
                                      sockaddr *addr, int addrlen);
 
+bool numeric_host(const char *hostname);
+
 int check_cert(SSL *ssl);
 
 void setup_ssl_lock();