[PATCH] [RFC] HDP: reject MDL reconnection with different MTU

["Elvis Pfützenreuter" <epx@signove.com>]

From: Elvis Pfutzenreuter <epx@signove.com>

This patch implements refusal of a MDL reconnection if the new L2CAP
connection presents a different MTU. Accordingly to HDP spec. item 3.5.

It aims to pass the TC_SNK_HCT_BV_07_C PTS test. (It does not pass yet
because PTS itself seems to have issues. See ticket 7121 for details.)
---
 health/hdp.c       |   17 +++++++++++++++--
 health/hdp_types.h |    1 +
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/health/hdp.c b/health/hdp.c
index dc1f803..4f89958 100644
--- a/health/hdp.c
+++ b/health/hdp.c
@@ -874,6 +874,7 @@ static gboolean check_channel_conf(struct hdp_channel *chan)
 	GError *err = NULL;
 	GIOChannel *io;
 	uint8_t mode;
+	uint16_t mtu;
 	int fd;
 
 	fd = mcap_mdl_get_fd(chan->mdl);
@@ -883,6 +884,7 @@ static gboolean check_channel_conf(struct hdp_channel *chan)
 
 	if (!bt_io_get(io, BT_IO_L2CAP, &err,
 			BT_IO_OPT_MODE, &mode,
+			BT_IO_OPT_OMTU, &mtu,
 			BT_IO_OPT_INVALID)) {
 		error("Error: %s", err->message);
 		g_io_channel_unref(io);
@@ -894,13 +896,24 @@ static gboolean check_channel_conf(struct hdp_channel *chan)
 
 	switch (chan->config) {
 	case HDP_RELIABLE_DC:
-		return mode == L2CAP_MODE_ERTM;
+		if (mode != L2CAP_MODE_ERTM)
+			return FALSE;
+		break;
 	case HDP_STREAMING_DC:
-		return mode == L2CAP_MODE_STREAMING;
+		if (mode != L2CAP_MODE_STREAMING)
+			return FALSE;
+		break;
 	default:
 		error("Error: Connected with unknown configuration");
 		return FALSE;
 	}
+
+	DBG("MDL MTU: %d; Channel MTU: %d", mtu, chan->mtu);
+
+	if (!chan->mtu)
+		chan->mtu = mtu;
+
+	return chan->mtu == mtu;
 }
 
 static void hdp_mcap_mdl_connected_cb(struct mcap_mdl *mdl, void *data)
diff --git a/health/hdp_types.h b/health/hdp_types.h
index fffdb32..714cf9a 100644
--- a/health/hdp_types.h
+++ b/health/hdp_types.h
@@ -120,6 +120,7 @@ struct hdp_channel {
 	uint8_t			config;		/* Channel configuration */
 	uint8_t			mdep;		/* Remote MDEP */
 	uint16_t		mdlid;		/* Data channel Id */
+	uint16_t		mtu;		/* Channel MTU */
 	struct hdp_echo_data	*edata;		/* private data used by echo channels */
 	gint			ref;		/* Reference counter */
 };
-- 
1.7.0.4