[PATCH BlueZ v1 1/2] shared/att: Call io_shutdown on ATT violations.

[Arman Uguray <armansito@xxxxxxxxxxxx>]

The existing code handles ATT protocol request timeouts and invalid
incoming request PDUs by cleaning up the io structure via io_destroy.
This doesn't always work, since this only terminates the connection if
io_set_close_on_destroy has been set. Calling io_destroy to force a
disconnect also has the added side-effect of not invoking the disconnect
callback registered with struct io.

This patch fixes these by calling io_shutdown on the io instead when
required by ATT protocol specification. This both cleans up the
connection regardless of whether or not close_on_unref has been set, and
it triggers the disconnect callback via an EPOLLHUP event.
---
 src/shared/att.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/shared/att.c b/src/shared/att.c
index 2bc7682..bc01827 100644
--- a/src/shared/att.c
+++ b/src/shared/att.c
@@ -416,9 +416,6 @@ static bool timeout_cb(void *user_data)
 	if (!op)
 		return false;
 
-	io_destroy(att->io);
-	att->io = NULL;
-
 	util_debug(att->debug_callback, att->debug_data,
 				"Operation timed out: 0x%02x", op->opcode);
 
@@ -428,6 +425,13 @@ static bool timeout_cb(void *user_data)
 	op->timeout_id = 0;
 	destroy_att_send_op(op);
 
+	/*
+	 * Directly terminate the connection as required by the ATT protocol.
+	 * This should trigger an io disconnect event which will clean up the
+	 * io and notify the upper layer.
+	 */
+	io_shutdown(att->io);
+
 	return false;
 }
 
@@ -579,7 +583,7 @@ static void handle_rsp(struct bt_att *att, uint8_t opcode, uint8_t *pdu,
 	if (!op) {
 		util_debug(att->debug_callback, att->debug_data,
 					"Received unexpected ATT response");
-		disconnect_cb(att->io, att);
+		io_shutdown(att->io);
 		return;
 	}
 
@@ -634,7 +638,7 @@ static void handle_conf(struct bt_att *att, uint8_t *pdu, ssize_t pdu_len)
 	if (!op || pdu_len) {
 		util_debug(att->debug_callback, att->debug_data,
 				"Received unexpected/invalid ATT confirmation");
-		disconnect_cb(att->io, att);
+		io_shutdown(att->io);
 		return;
 	}
 
@@ -765,14 +769,15 @@ static bool can_read_data(struct io *io, void *user_data)
 	case ATT_OP_TYPE_REQ:
 		/*
 		 * If a request is currently pending, then the sequential
-		 * protocol was violated. Disconnect the bearer and notify the
-		 * upper-layer.
+		 * protocol was violated. Disconnect the bearer, which will
+		 * promptly notify the upper layer via disconnect handlers.
 		 */
 		if (att->in_req) {
 			util_debug(att->debug_callback, att->debug_data,
 					"Received request while another is "
 					"pending: 0x%02x", opcode);
-			disconnect_cb(att->io, att);
+			io_shutdown(att->io);
+
 			return false;
 		}
 
-- 
2.1.0.rc2.206.gedb03e5

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