From: Xie He <xie.he.0141@xxxxxxxxx> [ 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@xxxxxxxxx> Signed-off-by: Xie He <xie.he.0141@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 cc33441af4691..50804d0473083 100644 --- a/drivers/net/wan/hdlc_cisco.c +++ b/drivers/net/wan/hdlc_cisco.c @@ -118,6 +118,7 @@ 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 12b35404cd8e7..d6cfd51613ed8 100644 --- a/drivers/net/wan/hdlc_fr.c +++ b/drivers/net/wan/hdlc_fr.c @@ -433,6 +433,8 @@ 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; } @@ -555,6 +557,7 @@ 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 16f33d1ffbfb9..64f8556513369 100644 --- a/drivers/net/wan/hdlc_ppp.c +++ b/drivers/net/wan/hdlc_ppp.c @@ -251,6 +251,7 @@ 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); } -- 2.25.1
