[PATCH net-next 0/2] Dissect PTP L2 packet header

[PATCH net-next 0/2] Dissect PTP L2 packet header

[Eran Ben Elisha]

Hi Jakub, Dave,

This series adds support for dissecting PTP L2 packet
header (EtherType 0x88F7).

For packet header dissecting, skb->protocol is needed. Add protocol
parsing operation to vlan ops, to guarantee skb->protocol is set,
as EtherType 0x88F7 occasionally follows a vlan header.

Eran Ben Elisha (2):
  net: vlan: Add parse protocol header ops
  net: flow_dissector: Parse PTP L2 packet header

 net/8021q/vlan_dev.c      |  9 +++++++++
 net/core/flow_dissector.c | 16 ++++++++++++++++
 2 files changed, 25 insertions(+)

-- 
2.17.1

[PATCH net-next 1/2] net: vlan: Add parse protocol header ops

[Eran Ben Elisha]

Add parse protocol header ops for vlan device. Before this patch, vlan
tagged packet transmitted by af_packet had skb->protocol unset. Some
kernel methods (like __skb_flow_dissect()) rely on this missing information
for its packet processing.

Signed-off-by: Eran Ben Elisha <eranbe@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
 net/8021q/vlan_dev.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index ec8408d1638f..dc1a197792e6 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -510,9 +510,17 @@ static void vlan_dev_set_lockdep_class(struct net_device *dev)
 	netdev_for_each_tx_queue(dev, vlan_dev_set_lockdep_one, NULL);
 }
 
+static __be16 vlan_parse_protocol(const struct sk_buff *skb)
+{
+	struct vlan_ethhdr *veth = (struct vlan_ethhdr *)(skb->data);
+
+	return __vlan_get_protocol(skb, veth->h_vlan_proto, NULL);
+}
+
 static const struct header_ops vlan_header_ops = {
 	.create	 = vlan_dev_hard_header,
 	.parse	 = eth_header_parse,
+	.parse_protocol = vlan_parse_protocol,
 };
 
 static int vlan_passthru_hard_header(struct sk_buff *skb, struct net_device *dev,
@@ -532,6 +540,7 @@ static int vlan_passthru_hard_header(struct sk_buff *skb, struct net_device *dev
 static const struct header_ops vlan_passthru_header_ops = {
 	.create	 = vlan_passthru_hard_header,
 	.parse	 = eth_header_parse,
+	.parse_protocol = vlan_parse_protocol,
 };
 
 static struct device_type vlan_type = {
-- 
2.17.1

[PATCH net-next 2/2] net: flow_dissector: Parse PTP L2 packet header

[Eran Ben Elisha]

Add support for parsing PTP L2 packet header. Such packet consists
of an L2 header (with ethertype of ETH_P_1588), PTP header, body
and an optional suffix.

Signed-off-by: Eran Ben Elisha <eranbe@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
 net/core/flow_dissector.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 6f1adba6695f..fcaa223c7cdc 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -23,6 +23,7 @@
 #include <linux/if_ether.h>
 #include <linux/mpls.h>
 #include <linux/tcp.h>
+#include <linux/ptp_classify.h>
 #include <net/flow_dissector.h>
 #include <scsi/fc/fc_fcoe.h>
 #include <uapi/linux/batadv_packet.h>
@@ -1251,6 +1252,21 @@ bool __skb_flow_dissect(const struct net *net,
 						  &proto, &nhoff, hlen, flags);
 		break;
 
+	case htons(ETH_P_1588): {
+		struct ptp_header *hdr, _hdr;
+
+		hdr = __skb_header_pointer(skb, nhoff, sizeof(_hdr), data,
+					   hlen, &_hdr);
+		if (!hdr || (hlen - nhoff) < sizeof(_hdr)) {
+			fdret = FLOW_DISSECT_RET_OUT_BAD;
+			break;
+		}
+
+		nhoff += ntohs(hdr->message_length);
+		fdret = FLOW_DISSECT_RET_OUT_GOOD;
+		break;
+	}
+
 	default:
 		fdret = FLOW_DISSECT_RET_OUT_BAD;
 		break;
-- 
2.17.1

Re: [PATCH net-next 0/2] Dissect PTP L2 packet header

[Jakub Kicinski]

On Thu, 7 Jan 2021 14:38:58 +0200 Eran Ben Elisha wrote:
> Hi Jakub, Dave,
> 
> This series adds support for dissecting PTP L2 packet
> header (EtherType 0x88F7).
> 
> For packet header dissecting, skb->protocol is needed. Add protocol
> parsing operation to vlan ops, to guarantee skb->protocol is set,
> as EtherType 0x88F7 occasionally follows a vlan header.

Please make an effort to add people who can give you reviews on CC 
and repost.