[PATCH] Allow LAPB users know which data were actually sent.

[PATCH] Allow LAPB users know which data were actually sent.

[Sergey Lapin]

Normally, when LAPB is transport layer for X.25 protocol,
internal mechanics of X.25 knows wheather data were actually
received by peer. But for non-X.25 protocols which use LAPB
as data reliability layer, it is important to have some way
to know what was actually sent, so we add transmit indication.

This change doesn't affext X.25 in any way.

Signed-off-by: Sergey Lapin <slapin@ossfans.org>
---
 include/linux/lapb.h  |    2 ++
 include/net/lapb.h    |    2 ++
 net/lapb/lapb_iface.c |   13 +++++++++++++
 net/lapb/lapb_subr.c  |    1 +
 4 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/include/linux/lapb.h b/include/linux/lapb.h
index ce709e1..a57cac0 100644
--- a/include/linux/lapb.h
+++ b/include/linux/lapb.h
@@ -30,6 +30,8 @@ struct lapb_register_struct {
 	void (*disconnect_indication)(struct net_device *dev, int reason);
 	int  (*data_indication)(struct net_device *dev, struct sk_buff *skb);
 	void (*data_transmit)(struct net_device *dev, struct sk_buff *skb);
+	void (*data_transmit_indication)(struct net_device *dev,
+			struct sk_buff *skb);
 };
 
 struct lapb_parms_struct {
diff --git a/include/net/lapb.h b/include/net/lapb.h
index 96cb5dd..b720ffa 100644
--- a/include/net/lapb.h
+++ b/include/net/lapb.h
@@ -111,6 +111,8 @@ extern void lapb_disconnect_confirmation(struct lapb_cb *lapb, int);
 extern void lapb_disconnect_indication(struct lapb_cb *lapb, int);
 extern int  lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *);
 extern int  lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *);
+extern void  lapb_data_transmit_indication(struct lapb_cb *lapb,
+				struct sk_buff *);
 
 /* lapb_in.c */
 extern void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *);
diff --git a/net/lapb/lapb_iface.c b/net/lapb/lapb_iface.c
index d5d8d55..024045f 100644
--- a/net/lapb/lapb_iface.c
+++ b/net/lapb/lapb_iface.c
@@ -423,6 +423,19 @@ int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
 	return used;
 }
 
+/* Here we indicate what we have just sent and received ack for
+ * This will allow us know what actually was sent */
+void lapb_data_transmit_indication(struct lapb_cb *lapb,
+					struct sk_buff *skb)
+{
+	int used = 0;
+	if (lapb->callbacks.data_transmit) {
+		lapb->callbacks.data_transmit_indication(lapb->dev, skb);
+		used = 1;
+	}
+	return used;
+}
+
 EXPORT_SYMBOL(lapb_register);
 EXPORT_SYMBOL(lapb_unregister);
 EXPORT_SYMBOL(lapb_getparms);
diff --git a/net/lapb/lapb_subr.c b/net/lapb/lapb_subr.c
index 43a2a7f..87ec449 100644
--- a/net/lapb/lapb_subr.c
+++ b/net/lapb/lapb_subr.c
@@ -60,6 +60,7 @@ void lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr)
 	if (lapb->va != nr)
 		while (skb_peek(&lapb->ack_queue) && lapb->va != nr) {
 			skb = skb_dequeue(&lapb->ack_queue);
+			lapb_data_transmit_indication(lapb, skb);
 			kfree_skb(skb);
 			lapb->va = (lapb->va + 1) % modulus;
 		}
-- 
1.7.4.1

Re: [PATCH] Allow LAPB users know which data were actually sent.

[Alan Cox]

On Thu, 17 Mar 2011 18:20:22 -0400
Sergey Lapin <slapin@ossfans.org> wrote:

> Normally, when LAPB is transport layer for X.25 protocol,
> internal mechanics of X.25 knows wheather data were actually
> received by peer. But for non-X.25 protocols which use LAPB
> as data reliability layer, it is important to have some way
> to know what was actually sent, so we add transmit indication.

Looks sensible but your patch doesn't add a user for it so what is it
needed for ?

Re: [PATCH] Allow LAPB users know which data were actually sent.

[Sergey Lapin]

On Thu, Mar 17, 2011 at 11:55:32PM +0000, Alan Cox wrote:
> On Thu, 17 Mar 2011 18:20:22 -0400
> Sergey Lapin <slapin@ossfans.org> wrote:
> 
> > Normally, when LAPB is transport layer for X.25 protocol,
> > internal mechanics of X.25 knows wheather data were actually
> > received by peer. But for non-X.25 protocols which use LAPB
> > as data reliability layer, it is important to have some way
> > to know what was actually sent, so we add transmit indication.
> 
> Looks sensible but your patch doesn't add a user for it so what is it
> needed for ?

I implement accessor for special equipment (acessing fiscal information)
which uses custom protocol over LAPB. As it is being implemented,
I actually wanted to know if this approach for using LAPB is good enough
for mainline submission, as I want to have kernel part to be in mainline.
I think I will have the rest of patches ready within two weeks.

All the best,
S.

Re: [PATCH] Allow LAPB users know which data were actually sent.

[David Miller]

From: Sergey Lapin <slapin@ossfans.org>
Date: Thu, 17 Mar 2011 20:52:20 -0400

> I implement accessor for special equipment (acessing fiscal information)
> which uses custom protocol over LAPB. As it is being implemented,
> I actually wanted to know if this approach for using LAPB is good enough
> for mainline submission, as I want to have kernel part to be in mainline.
> I think I will have the rest of patches ready within two weeks.

Submit the infrastructure for inclusion when you're user is completed
and submittable as well.

Thanks.

Re: [PATCH] Allow LAPB users know which data were actually sent.

[Alan Cox]

> > Looks sensible but your patch doesn't add a user for it so what is it
> > needed for ?
> 
> I implement accessor for special equipment (acessing fiscal information)
> which uses custom protocol over LAPB. As it is being implemented,
> I actually wanted to know if this approach for using LAPB is good enough
> for mainline submission, as I want to have kernel part to be in mainline.
> I think I will have the rest of patches ready within two weeks.

It seems sensible as an implementation to me so I would carry on using
that model and then submit it with all the other bits when you are ready.