From 529d96dc6085c5ce3bbe71b05e2e080fbf35dd68 Mon Sep 17 00:00:00 2001
From: Michael Haberler <git@mah.priv.at>
Date: Sun, 10 Aug 2014 12:30:01 +0200
Subject: [PATCH] protocol selection: enable FILTER_PROTOCOL_CONNECTION to
 choose and set a protocol

So far agreeable protocol names were limited to what struct libwebsocket_protocols
had to offer.

With the wildcard matching of protocol name in an earlier commit, FILTER_PROTOCOL_CONNECTION
can now inspect and parse the WSI_TOKEN_PROTOCOL header, and explicitly
set a protocol by calling libwebsocket_set_protocol(wsi, name, <optional struct libwebsocket_protocols *>)

The Sec-WebSocket-Protocol: reply will contain only the default or matched
protocol name as selected in FILTER_PROTOCOL_CONNECTION.

The current protocol name can be accessed via
const char *libwebsockets_get_protocol_name(struct libwebsocket *wsi).

A LWS_CALLBACK_FILTER_PROTOCOL_CONNECTION callback would do roughly this:

lws_hdr_copy(wsi, protocols, sizeof protocols, WSI_TOKEN_PROTOCOL);
..inspect protocols and choose a proto name and struct libwebsocket_protocols:
..call libwebsocket_set_protocol(wsi,name, <opt proto if not default>);

Also deals with issue #147 (incorrect Sec-WebSocket-Protocol: reply).
---
 lib/libwebsockets.c         |  8 ++++++++
 lib/libwebsockets.h         |  8 ++++++++
 lib/private-libwebsockets.h |  1 +
 lib/server-handshake.c      |  9 +++++----
 lib/server.c                | 11 +++++++++++
 5 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/lib/libwebsockets.c b/lib/libwebsockets.c
index ee88e2e1b..8ef87c1bb 100644
--- a/lib/libwebsockets.c
+++ b/lib/libwebsockets.c
@@ -669,6 +669,14 @@ libwebsockets_get_protocol(struct libwebsocket *wsi)
 	return wsi->protocol;
 }
 
+LWS_VISIBLE const char *
+libwebsockets_get_protocol_name(struct libwebsocket *wsi)
+{
+    if (wsi->selected_protocol)
+	return wsi->selected_protocol;
+    return wsi->protocol->name;
+}
+
 LWS_VISIBLE int
 libwebsocket_is_final_fragment(struct libwebsocket *wsi)
 {
diff --git a/lib/libwebsockets.h b/lib/libwebsockets.h
index 203c54e1c..3bc7be2b1 100644
--- a/lib/libwebsockets.h
+++ b/lib/libwebsockets.h
@@ -1036,6 +1036,11 @@ LWS_VISIBLE LWS_EXTERN void
 libwebsocket_set_timeout(struct libwebsocket *wsi,
 					 enum pending_timeout reason, int secs);
 
+LWS_VISIBLE LWS_EXTERN void
+libwebsocket_set_protocol(struct libwebsocket *wsi,
+			  char *protocol_name,
+			  struct libwebsocket_protocols *proto);
+
 /*
  * IMPORTANT NOTICE!
  *
@@ -1095,6 +1100,9 @@ LWS_VISIBLE LWS_EXTERN int libwebsockets_return_http_status(
 LWS_VISIBLE LWS_EXTERN const struct libwebsocket_protocols *
 libwebsockets_get_protocol(struct libwebsocket *wsi);
 
+LWS_VISIBLE LWS_EXTERN const char *
+libwebsockets_get_protocol_name(struct libwebsocket *wsi);
+
 LWS_VISIBLE LWS_EXTERN int
 libwebsocket_callback_on_writable(struct libwebsocket_context *context,
 						      struct libwebsocket *wsi);
diff --git a/lib/private-libwebsockets.h b/lib/private-libwebsockets.h
index 4194498ec..7e27fbc22 100755
--- a/lib/private-libwebsockets.h
+++ b/lib/private-libwebsockets.h
@@ -576,6 +576,7 @@ struct libwebsocket {
     struct lws_io_watcher w_write;
 #endif /* LWS_USE_LIBEV */
 	const struct libwebsocket_protocols *protocol;
+        char *selected_protocol;
 #ifndef LWS_NO_EXTENSIONS
 	struct libwebsocket_extension *
 				   active_extensions[LWS_MAX_EXTENSIONS_ACTIVE];
diff --git a/lib/server-handshake.c b/lib/server-handshake.c
index 56cf9a13e..200187f46 100644
--- a/lib/server-handshake.c
+++ b/lib/server-handshake.c
@@ -217,10 +217,11 @@ handshake_0405(struct libwebsocket_context *context, struct libwebsocket *wsi)
 
 	if (lws_hdr_total_length(wsi, WSI_TOKEN_PROTOCOL)) {
 		LWS_CPYAPP(p, "\x0d\x0aSec-WebSocket-Protocol: ");
-		n = lws_hdr_copy(wsi, p, 128, WSI_TOKEN_PROTOCOL);
-		if (n < 0)
-			goto bail;
-		p += n;
+		const char *proto = wsi->selected_protocol ? wsi->selected_protocol :
+		    wsi->protocol->name;
+		lwsl_debug("replying with selected proto='%s'\n", proto);
+		strcpy(p, proto);
+		p += strlen(proto);
 	}
 
 #ifndef LWS_NO_EXTENSIONS
diff --git a/lib/server.c b/lib/server.c
index 5b0b23de2..cc2a3a362 100644
--- a/lib/server.c
+++ b/lib/server.c
@@ -950,3 +950,14 @@ lws_server_get_canonical_hostname(struct libwebsocket_context *context,
 
 	lwsl_notice(" canonical_hostname = %s\n", context->canonical_hostname);
 }
+
+LWS_VISIBLE void
+libwebsocket_set_protocol(struct libwebsocket *wsi,
+			  char *protocol_name,
+			  struct libwebsocket_protocols *proto)
+{
+    wsi->selected_protocol = protocol_name;
+    if (proto)
+	wsi->protocol = proto;
+}
+