2014-12-01 12:54:06

by Jakub Tyszkowski

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

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

2014-12-03 11:48:52

by Szymon Janc

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

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