Detect invalid HTTP/2 preface errors

And make sure all HTTP/2 connection_error(s) result in a
gun_down message containing the error. In the preface case
we do not send a gun_error message (because there's no stream
open yet) and gun_down was always saying normal.

Also make sure the human readable reason is included in the
gun_error message, if any.

1 files changed, 71 insertions, 0 deletions

diff --git a/test/rfc7540_SUITE.erl b/test/rfc7540_SUITE.erl
index f19ce34..780f850 100644
--- a/test/rfc7540_SUITE.erl
+++ b/test/rfc7540_SUITE.erl
@@ -70,6 +70,77 @@ do_authority_port(Transport0, DefaultPort, AuthorityHeaderPort) ->
 	AuthorityHeaderPort = Rest,
 	gun:close(ConnPid).
 
+prior_knowledge_preface_garbage(_) ->
+	doc("A PROTOCOL_ERROR connection error must result from the server sending "
+		"an invalid preface in the form of garbage when connecting "
+		"using the prior knowledge method. (RFC7540 3.4, RFC7540 3.5)"),
+	%% We use 'http' here because we are going to do the handshake manually.
+	{ok, OriginPid, Port} = init_origin(tcp, http, fun(_, Socket, Transport) ->
+		ok = Transport:send(Socket, <<0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15>>),
+		timer:sleep(100)
+	end),
+	{ok, ConnPid} = gun:open("localhost", Port, #{protocols => [http2]}),
+	{ok, http2} = gun:await_up(ConnPid),
+	handshake_completed = receive_from(OriginPid),
+	receive
+		{gun_down, ConnPid, http2, {error, {connection_error, protocol_error,
+				'Invalid connection preface received. (RFC7540 3.5)'}}, []} ->
+			gun:close(ConnPid);
+		Msg ->
+			error({unexpected_msg, Msg})
+	after 1000 ->
+		error(timeout)
+	end.
+
+prior_knowledge_preface_http1(_) ->
+	doc("A PROTOCOL_ERROR connection error must result from the server sending "
+		"an invalid preface in the form of an HTTP/1.1 response when connecting "
+		"using the prior knowledge method. (RFC7540 3.4, RFC7540 3.5)"),
+	%% We use 'http' here because we are going to do the handshake manually.
+	{ok, OriginPid, Port} = init_origin(tcp, http, fun(_, Socket, Transport) ->
+		ok = Transport:send(Socket, <<
+			"HTTP/1.1 400 Bad Request\r\n"
+			"Connection: close\r\n"
+			"Content-Length: 0\r\n"
+			"Date: Thu, 27 Feb 2020 09:32:17 GMT\r\n"
+			"\r\n">>),
+		timer:sleep(100)
+	end),
+	{ok, ConnPid} = gun:open("localhost", Port, #{protocols => [http2]}),
+	{ok, http2} = gun:await_up(ConnPid),
+	handshake_completed = receive_from(OriginPid),
+	receive
+		{gun_down, ConnPid, http2, {error, {connection_error, protocol_error,
+				'Invalid connection preface received. (RFC7540 3.5)'}}, []} ->
+			gun:close(ConnPid);
+		Msg ->
+			error({unexpected_msg, Msg})
+	after 1000 ->
+		error(timeout)
+	end.
+
+prior_knowledge_preface_other_frame(_) ->
+	doc("A PROTOCOL_ERROR connection error must result from the server sending "
+		"an invalid preface in the form of a non-SETTINGS frame when connecting "
+		"using the prior knowledge method. (RFC7540 3.4, RFC7540 3.5)"),
+	%% We use 'http' here because we are going to do the handshake manually.
+	{ok, OriginPid, Port} = init_origin(tcp, http, fun(_, Socket, Transport) ->
+		ok = Transport:send(Socket, cow_http2:window_update(1)),
+		timer:sleep(100)
+	end),
+	{ok, ConnPid} = gun:open("localhost", Port, #{protocols => [http2]}),
+	{ok, http2} = gun:await_up(ConnPid),
+	handshake_completed = receive_from(OriginPid),
+	receive
+		{gun_down, ConnPid, http2, {error, {connection_error, protocol_error,
+				'Invalid connection preface received. (RFC7540 3.5)'}}, []} ->
+			gun:close(ConnPid);
+		Msg ->
+			error({unexpected_msg, Msg})
+	after 1000 ->
+		error(timeout)
+	end.
+
 lingering_data_counts_toward_connection_window(_) ->
 	doc("DATA frames received after sending RST_STREAM must be counted "
 		"toward the connection flow-control window. (RFC7540 5.1)"),