[PATCHv2] gattrib: Fix not changing the buffer size when mtu is reduced

[PATCHv2] gattrib: Fix not changing the buffer size when mtu is reduced

[Jakub Tyszkowski]

Using larger buffer than mtu resulted in not sending the message at all
as encode_pdu() in shared/att.c fails when provided data buffer is
larger than current mtu.
---
 attrib/gattrib.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/attrib/gattrib.c b/attrib/gattrib.c
index a04a0ee..cfa3b78 100644
--- a/attrib/gattrib.c
+++ b/attrib/gattrib.c
@@ -324,11 +324,17 @@ uint8_t *g_attrib_get_buffer(GAttrib *attrib, size_t *len)
 
 gboolean g_attrib_set_mtu(GAttrib *attrib, int mtu)
 {
-	/* Clients of this expect a buffer to use. */
-	if (mtu > attrib->buflen) {
+	/*
+	 * Clients of this expect a buffer to use.
+	 *
+	 * Pdu encoding in sharred/att verifies if whole buffer fits the mtu,
+	 * thus we should set the buflen also when mtu is reduced. But we
+	 * need to reallocate the buffer only if mtu is larger.
+	 */
+	if (mtu > attrib->buflen)
 		attrib->buf = g_realloc(attrib->buf, mtu);
-		attrib->buflen = mtu;
-	}
+
+	attrib->buflen = mtu;
 
 	return bt_att_set_mtu(attrib->att, mtu);
 }
-- 
1.9.1

Re: [PATCHv2] gattrib: Fix not changing the buffer size when mtu is reduced

[Szymon Janc]

Hi Jakub,

On Monday 01 of December 2014 13:54:06 Jakub Tyszkowski wrote:
> Using larger buffer than mtu resulted in not sending the message at all
> as encode_pdu() in shared/att.c fails when provided data buffer is
> larger than current mtu.
> ---
>  attrib/gattrib.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/attrib/gattrib.c b/attrib/gattrib.c
> index a04a0ee..cfa3b78 100644
> --- a/attrib/gattrib.c
> +++ b/attrib/gattrib.c
> @@ -324,11 +324,17 @@ uint8_t *g_attrib_get_buffer(GAttrib *attrib, size_t *len)
>  
>  gboolean g_attrib_set_mtu(GAttrib *attrib, int mtu)
>  {
> -	/* Clients of this expect a buffer to use. */
> -	if (mtu > attrib->buflen) {
> +	/*
> +	 * Clients of this expect a buffer to use.
> +	 *
> +	 * Pdu encoding in sharred/att verifies if whole buffer fits the mtu,
> +	 * thus we should set the buflen also when mtu is reduced. But we
> +	 * need to reallocate the buffer only if mtu is larger.
> +	 */
> +	if (mtu > attrib->buflen)
>  		attrib->buf = g_realloc(attrib->buf, mtu);
> -		attrib->buflen = mtu;
> -	}
> +
> +	attrib->buflen = mtu;
>  
>  	return bt_att_set_mtu(attrib->att, mtu);
>  }

Pushed, thanks.

-- 
Best regards, 
Szymon Janc