[PATCH 1/1] shared/gatt-client: Fix the "Find Information req" error

From: "nagaraj.dr" <redacted>

characteristic descriptor is searched b/w the
characteristic "value_handle + 1" and
characteristic "end_handle" using "Find Information req"

if remote device had declared the characteristic value_handle
at 0XFFFF (which also means there is no characteristic descriptors),then
present code would make start_handle has 0X0000(because of 16 bit
integer overflow) for "Find Information req"

desc_start = chrc_data->value_handle + 1;

 Consequence:  Below request will be sent,
        ATT: Find Information req (0x04)
        start 0x0000, end 0xffff

        and below will be the proper response from the remote device
        ATT: Error (0x01)
        Error: Invalid handle (1)
        Find Information req (0x04) on handle 0x0000
---
 src/shared/gatt-client.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index 7bc3b71..9b944ee 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c

@@ -601,13 +601,13 @@ static bool discover_descs(struct discovery_op *op, bool *discovering)
 							chrc_data->value_handle)
 			goto failed;
 
-		desc_start = chrc_data->value_handle + 1;
-
-		if (desc_start > chrc_data->end_handle) {
+		if (chrc_data->value_handle >= chrc_data->end_handle) {
 			free(chrc_data);
 			continue;
 		}
 
+		desc_start = chrc_data->value_handle + 1;
+
 		client->discovery_req = bt_gatt_discover_descriptors(
 							client->att, desc_start,
 							chrc_data->end_handle,

-- 
1.7.9.5