gatt client clones break indication/confirmation

gatt client clones break indication/confirmation

[Mikhail Krivtsov]

[-- Attachment #1: Type: text/plain, Size: 821 bytes --]

When bt_gatt_client receives 'indication' it sends 'confirmation'.
'confirmation' sending was broken after adding support for 'clones' of
bt_gatt_client. In addition to first bt_gatt_client each clone also
sends 'confirmation'.

# > ACL Data RX: Handle 69 flags 0x02 dlen 27
#       ATT: Handle Value Indication (0x1d) len 22
#         Handle: 0x001f
#           Data: 68656c6c6f2027302e302e302e303a3532353332
# < ACL Data TX: Handle 69 flags 0x00 dlen 5
#       ATT: Handle Value Confirmation (0x1e) len 0
# < ACL Data TX: Handle 69 flags 0x00 dlen 5
#       ATT: Handle Value Confirmation (0x1e) len 0

Extra confirmation sent by clone confuses remote side. When bluetooth
daemon receives extra confirmation it breaks connection.

Attached patch fixes the issue limiting confirmation sending to single
bt_gatt_client.


[-- Attachment #2: 0001-shared-gatt-client_Fix_sending_confirmation.patch --]
[-- Type: text/x-patch, Size: 1312 bytes --]

>>From e470089b4b5788ab5d2ec9af21bffee4f9240c97 Mon Sep 17 00:00:00 2001
From: "Mikhail I. Krivtsov" <mikhail.krivtsov@gmail.com>
Date: Sat, 14 May 2016 11:37:30 +0300
Subject: [PATCH] shared/gatt-client: Fix sending confirmation

Confirmation shall be sent from topmost parent only.
Extra confirmation sent by clone confuses remote side.

> ACL Data RX: Handle 69 flags 0x02 dlen 27
      ATT: Handle Value Indication (0x1d) len 22
        Handle: 0x001f
          Data: 68656c6c6f2027302e302e302e303a3532353332
< ACL Data TX: Handle 69 flags 0x00 dlen 5
      ATT: Handle Value Confirmation (0x1e) len 0
< ACL Data TX: Handle 69 flags 0x00 dlen 5
      ATT: Handle Value Confirmation (0x1e) len 0
---
 src/shared/gatt-client.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/shared/gatt-client.c b/src/shared/gatt-client.c
index 84689f6..adabfe3 100644
--- a/src/shared/gatt-client.c
+++ b/src/shared/gatt-client.c
@@ -1745,7 +1745,7 @@ static void notify_cb(uint8_t opcode, const void *pdu, uint16_t length,
 
 	queue_foreach(client->notify_list, notify_handler, &pdu_data);
 
-	if (opcode == BT_ATT_OP_HANDLE_VAL_IND)
+	if (opcode == BT_ATT_OP_HANDLE_VAL_IND && !client->parent)
 		bt_att_send(client->att, BT_ATT_OP_HANDLE_VAL_CONF, NULL, 0,
 							NULL, NULL, NULL);
 
-- 
2.7.3

Re: gatt client clones break indication/confirmation

[Luiz Augusto von Dentz]

Hi Mikhail,

On Mon, May 23, 2016 at 12:57 PM, Mikhail Krivtsov
<mikhail.krivtsov@gmail.com> wrote:
> When bt_gatt_client receives 'indication' it sends 'confirmation'.
> 'confirmation' sending was broken after adding support for 'clones' of
> bt_gatt_client. In addition to first bt_gatt_client each clone also
> sends 'confirmation'.
>
> # > ACL Data RX: Handle 69 flags 0x02 dlen 27
> #       ATT: Handle Value Indication (0x1d) len 22
> #         Handle: 0x001f
> #           Data: 68656c6c6f2027302e302e302e303a3532353332
> # < ACL Data TX: Handle 69 flags 0x00 dlen 5
> #       ATT: Handle Value Confirmation (0x1e) len 0
> # < ACL Data TX: Handle 69 flags 0x00 dlen 5
> #       ATT: Handle Value Confirmation (0x1e) len 0
>
> Extra confirmation sent by clone confuses remote side. When bluetooth
> daemon receives extra confirmation it breaks connection.
>
> Attached patch fixes the issue limiting confirmation sending to single
> bt_gatt_client.

I went ahead and applied this fix, thanks for the contribution.

*Next time please do follow the instruction under HACKING and send as
a proper patch.


-- 
Luiz Augusto von Dentz