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From:   Pauli Virtanen <pav@iki.fi>
To:     linux-bluetooth@vger.kernel.org
Cc:     Pauli Virtanen <pav@iki.fi>
Subject: [PATCH BlueZ 2/2] avdtp: use separate local SEID pool for each adapter
Date:   Sun, 29 Aug 2021 18:50:12 +0300
Message-Id: <20210829155012.164880-3-pav@iki.fi>
In-Reply-To: <20210829155012.164880-1-pav@iki.fi>
References: <20210829155012.164880-1-pav@iki.fi>
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Local SEIDs are currently allocated from a pool that is common for all
adapters. However, AVDTP spec v1.3, sec 4.10 states "To prevent
conflicts, the scope of the SEID shall be both device-local and
connection-local. The application is responsible for assigning a SEID,
which is not in use on the connection to the same peer device." In
practice, registering the same media application for multiple adapters
can result to running out of SEIDs, even though the spec does not
require SEIDs to be unique across adapters.

Use a separate SEID pool for each btd_adapter to fix this.
---
 profiles/audio/a2dp.c  |  2 +-
 profiles/audio/avdtp.c | 55 ++++++++++++++++++++++++++++++++++++------
 profiles/audio/avdtp.h |  4 ++-
 3 files changed, 51 insertions(+), 10 deletions(-)

diff --git a/profiles/audio/a2dp.c b/profiles/audio/a2dp.c
index 02caa83e1..1e8a66b8a 100644
--- a/profiles/audio/a2dp.c
+++ b/profiles/audio/a2dp.c
@@ -2615,7 +2615,7 @@ struct a2dp_sep *a2dp_add_sep(struct btd_adapter *adapter, uint8_t type,
 
 	sep = g_new0(struct a2dp_sep, 1);
 
-	sep->lsep = avdtp_register_sep(server->seps, type,
+	sep->lsep = avdtp_register_sep(adapter, server->seps, type,
 					AVDTP_MEDIA_TYPE_AUDIO, codec,
 					delay_reporting, &endpoint_ind,
 					&cfm, sep);
diff --git a/profiles/audio/avdtp.c b/profiles/audio/avdtp.c
index 25520ceec..f2aa98b23 100644
--- a/profiles/audio/avdtp.c
+++ b/profiles/audio/avdtp.c
@@ -44,7 +44,6 @@
 #define AVDTP_PSM 25
 
 #define MAX_SEID 0x3E
-static uint64_t seids;
 
 #ifndef MAX
 # define MAX(x, y) ((x) > (y) ? (x) : (y))
@@ -325,6 +324,7 @@ struct avdtp_local_sep {
 	GSList *caps;
 	struct avdtp_sep_ind *ind;
 	struct avdtp_sep_cfm *cfm;
+	struct btd_adapter *adapter;
 	void *user_data;
 };
 
@@ -414,6 +414,8 @@ struct avdtp {
 
 static GSList *state_callbacks = NULL;
 
+static GHashTable *adapter_seids = NULL;
+
 static int send_request(struct avdtp *session, gboolean priority,
 			struct avdtp_stream *stream, uint8_t signal_id,
 			void *buffer, size_t size);
@@ -3768,7 +3770,41 @@ int avdtp_delay_report(struct avdtp *session, struct avdtp_stream *stream,
 							&req, sizeof(req));
 }
 
-struct avdtp_local_sep *avdtp_register_sep(struct queue *lseps, uint8_t type,
+static uint8_t get_adapter_seid(struct btd_adapter *adapter)
+{
+	uint64_t *seids;
+
+	if (adapter_seids == NULL)
+		adapter_seids = g_hash_table_new_full(g_direct_hash,
+						g_direct_equal, NULL, g_free);
+
+	seids = g_hash_table_lookup(adapter_seids, adapter);
+
+	if (seids == NULL) {
+		seids = g_new0(uint64_t, 1);
+		g_hash_table_insert(adapter_seids, adapter, seids);
+	}
+
+	return util_get_uid(seids, MAX_SEID);
+}
+
+static void clear_adapter_seid(struct btd_adapter *adapter, uint8_t seid)
+{
+	uint64_t *seids = adapter_seids ?
+			g_hash_table_lookup(adapter_seids, adapter) : NULL;
+
+	if (seids == NULL)
+		return;
+
+	util_clear_uid(seids, seid);
+
+	if (*seids == 0)
+		g_hash_table_remove(adapter_seids, adapter);
+}
+
+struct avdtp_local_sep *avdtp_register_sep(struct btd_adapter *adapter,
+						struct queue *lseps,
+						uint8_t type,
 						uint8_t media_type,
 						uint8_t codec_type,
 						gboolean delay_reporting,
@@ -3777,7 +3813,7 @@ struct avdtp_local_sep *avdtp_register_sep(struct queue *lseps, uint8_t type,
 						void *user_data)
 {
 	struct avdtp_local_sep *sep;
-	uint8_t seid = util_get_uid(&seids, MAX_SEID);
+	uint8_t seid = get_adapter_seid(adapter);
 
 	if (!seid)
 		return NULL;
@@ -3791,11 +3827,13 @@ struct avdtp_local_sep *avdtp_register_sep(struct queue *lseps, uint8_t type,
 	sep->codec = codec_type;
 	sep->ind = ind;
 	sep->cfm = cfm;
+	sep->adapter = adapter;
 	sep->user_data = user_data;
 	sep->delay_reporting = delay_reporting;
 
-	DBG("SEP %p registered: type:%d codec:%d seid:%d", sep,
-			sep->info.type, sep->codec, sep->info.seid);
+	DBG("SEP %p registered: type:%d codec:%d adapter:%p seid:%d", sep,
+			sep->info.type, sep->codec, sep->adapter,
+			sep->info.seid);
 
 	if (!queue_push_tail(lseps, sep)) {
 		g_free(sep);
@@ -3813,10 +3851,11 @@ int avdtp_unregister_sep(struct queue *lseps, struct avdtp_local_sep *sep)
 	if (sep->stream)
 		release_stream(sep->stream, sep->stream->session);
 
-	DBG("SEP %p unregistered: type:%d codec:%d seid:%d", sep,
-			sep->info.type, sep->codec, sep->info.seid);
+	DBG("SEP %p unregistered: type:%d codec:%d adapter:%p seid:%d", sep,
+			sep->info.type, sep->codec, sep->adapter,
+			sep->info.seid);
 
-	util_clear_uid(&seids, sep->info.seid);
+	clear_adapter_seid(sep->adapter, sep->info.seid);
 	queue_remove(lseps, sep);
 	g_free(sep);
 
diff --git a/profiles/audio/avdtp.h b/profiles/audio/avdtp.h
index b02534cd5..70807cff9 100644
--- a/profiles/audio/avdtp.h
+++ b/profiles/audio/avdtp.h
@@ -278,7 +278,9 @@ int avdtp_abort(struct avdtp *session, struct avdtp_stream *stream);
 int avdtp_delay_report(struct avdtp *session, struct avdtp_stream *stream,
 							uint16_t delay);
 
-struct avdtp_local_sep *avdtp_register_sep(struct queue *lseps, uint8_t type,
+struct avdtp_local_sep *avdtp_register_sep(struct btd_adapter *adapter,
+						struct queue *lseps,
+						uint8_t type,
 						uint8_t media_type,
 						uint8_t codec_type,
 						gboolean delay_reporting,
-- 
2.31.1