From: Xie He xie.he.0141@gmail.com
[ Upstream commit 9fb030a70431a2a2a1b292dbf0b2f399cc072c16 ]
This patch sets skb->protocol before transmitting frames on the HDLC device, so that a user listening on the HDLC device with an AF_PACKET socket will see outgoing frames' sll_protocol field correctly set and consistent with that of incoming frames.
1. Control frames in hdlc_cisco and hdlc_ppp
When these drivers send control frames, skb->protocol is not set.
This value should be set to htons(ETH_P_HDLC), because when receiving control frames, their skb->protocol is set to htons(ETH_P_HDLC).
When receiving, hdlc_type_trans in hdlc.h is called, which then calls cisco_type_trans or ppp_type_trans. The skb->protocol of control frames is set to htons(ETH_P_HDLC) so that the control frames can be received by hdlc_rcv in hdlc.c, which calls cisco_rx or ppp_rx to process the control frames.
2. hdlc_fr
When this driver sends control frames, skb->protocol is set to internal values used in this driver.
When this driver sends data frames (from upper stacked PVC devices), skb->protocol is the same as that of the user data packet being sent on the upper PVC device (for normal PVC devices), or is htons(ETH_P_802_3) (for Ethernet-emulating PVC devices).
However, skb->protocol for both control frames and data frames should be set to htons(ETH_P_HDLC), because when receiving, all frames received on the HDLC device will have their skb->protocol set to htons(ETH_P_HDLC).
When receiving, hdlc_type_trans in hdlc.h is called, and because this driver doesn't provide a type_trans function in struct hdlc_proto, all frames will have their skb->protocol set to htons(ETH_P_HDLC). The frames are then received by hdlc_rcv in hdlc.c, which calls fr_rx to process the frames (control frames are consumed and data frames are re-received on upper PVC devices).
Cc: Krzysztof Halasa khc@pm.waw.pl Signed-off-by: Xie He xie.he.0141@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wan/hdlc_cisco.c | 1 + drivers/net/wan/hdlc_fr.c | 3 +++ drivers/net/wan/hdlc_ppp.c | 1 + 3 files changed, 5 insertions(+)
diff --git a/drivers/net/wan/hdlc_cisco.c b/drivers/net/wan/hdlc_cisco.c index c169a26e5359..2c6e3fa6947a 100644 --- a/drivers/net/wan/hdlc_cisco.c +++ b/drivers/net/wan/hdlc_cisco.c @@ -121,6 +121,7 @@ static void cisco_keepalive_send(struct net_device *dev, u32 type, skb_put(skb, sizeof(struct cisco_packet)); skb->priority = TC_PRIO_CONTROL; skb->dev = dev; + skb->protocol = htons(ETH_P_HDLC); skb_reset_network_header(skb);
dev_queue_xmit(skb); diff --git a/drivers/net/wan/hdlc_fr.c b/drivers/net/wan/hdlc_fr.c index 67f89917277c..03b5f5cce6f4 100644 --- a/drivers/net/wan/hdlc_fr.c +++ b/drivers/net/wan/hdlc_fr.c @@ -436,6 +436,8 @@ static netdev_tx_t pvc_xmit(struct sk_buff *skb, struct net_device *dev) if (pvc->state.fecn) /* TX Congestion counter */ dev->stats.tx_compressed++; skb->dev = pvc->frad; + skb->protocol = htons(ETH_P_HDLC); + skb_reset_network_header(skb); dev_queue_xmit(skb); return NETDEV_TX_OK; } @@ -558,6 +560,7 @@ static void fr_lmi_send(struct net_device *dev, int fullrep) skb_put(skb, i); skb->priority = TC_PRIO_CONTROL; skb->dev = dev; + skb->protocol = htons(ETH_P_HDLC); skb_reset_network_header(skb);
dev_queue_xmit(skb); diff --git a/drivers/net/wan/hdlc_ppp.c b/drivers/net/wan/hdlc_ppp.c index 85844f26547d..20d9b6585fba 100644 --- a/drivers/net/wan/hdlc_ppp.c +++ b/drivers/net/wan/hdlc_ppp.c @@ -254,6 +254,7 @@ static void ppp_tx_cp(struct net_device *dev, u16 pid, u8 code,
skb->priority = TC_PRIO_CONTROL; skb->dev = dev; + skb->protocol = htons(ETH_P_HDLC); skb_reset_network_header(skb); skb_queue_tail(&tx_queue, skb); }