On Mon, 13 Jan 2020 13:45:51 +0100, Martin Schiller wrote:
o call skb_reset_network_header() before hdlc->xmit()
o change skb proto to HDLC (0x0019) before hdlc->xmit()
o call dev_queue_xmit_nit() before hdlc->xmit()
This changes make it possible to trace (tcpdump) outgoing layer2
(ETH_P_HDLC) packets
o use a copy of the skb for lapb_data_request() in x25_xmit()
It's not clear to me why
This fixes the problem, that tracing layer3 (ETH_P_X25) packets
results in a malformed first byte of the packets.
Signed-off-by: Martin Schiller <ms@xxxxxxxxxx>
---
drivers/net/wan/hdlc_x25.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/net/wan/hdlc_x25.c b/drivers/net/wan/hdlc_x25.c
index b28051eba736..434e5263eddf 100644
--- a/drivers/net/wan/hdlc_x25.c
+++ b/drivers/net/wan/hdlc_x25.c
@@ -72,6 +72,7 @@ static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
unsigned char *ptr;
skb_push(skb, 1);
+ skb_reset_network_header(skb);
if (skb_cow(skb, 1))
This skb_cow() here is for the next handler down to have a 1 byte of
headroom guaranteed? It'd seem more natural to have skb_cow before the
push.. not that it's related to your patch.
return NET_RX_DROP;
@@ -88,6 +89,9 @@ static int x25_data_indication(struct net_device *dev, struct sk_buff *skb)
static void x25_data_transmit(struct net_device *dev, struct sk_buff *skb)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
Please insert a new line after the variable declaration since you're
touching this one.
+ skb_reset_network_header(skb);
+ skb->protocol = hdlc_type_trans(skb, dev);
+ dev_queue_xmit_nit(skb, dev);
hdlc->xmit(skb, dev); /* Ignore return value :-( */
}