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Commit d5709f7a authored by Hadar Hen Zion's avatar Hadar Hen Zion Committed by David S. Miller
Browse files

flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci 



Early in the datapath skb_vlan_untag function is called, stripped
the vlan from the skb and set skb->vlan_tci and skb->vlan_proto fields.

The current dissection doesn't handle stripped vlan packets correctly.
In some flows, vlan doesn't exist in skb->data anymore when applying
flow dissection on the skb, fix that.

In case vlan info wasn't stripped before applying flow_dissector (RPS
flow for example), or in case of skb with multiple vlans (e.g. 802.1ad),
get the vlan info from skb->data. The flow_dissector correctly skips
any number of vlans and stores only the first level vlan.

Fixes: 0744dd00 ('net: introduce skb_flow_dissect()')
Signed-off-by: default avatarHadar Hen Zion <hadarh@mellanox.com>
Acked-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 92bcdcc6

net/core/flow_dissector.c

+26 −8
Original line number Diff line number Diff line
@@ -119,12 +119,14 @@ bool __skb_flow_dissect(const struct sk_buff *skb, 
	struct flow_dissector_key_ports *key_ports;

	struct flow_dissector_key_tags *key_tags;

	struct flow_dissector_key_keyid *key_keyid;

	bool skip_vlan = false;

	u8 ip_proto = 0;

	bool ret = false;



	if (!data) {

		data = skb->data;

		proto = skb->protocol;

		proto = skb_vlan_tag_present(skb) ?

			 skb->vlan_proto : skb->protocol;

		nhoff = skb_network_offset(skb);

		hlen = skb_headlen(skb);

	}
@@ -243,23 +245,39 @@ bool __skb_flow_dissect(const struct sk_buff *skb, 
	case htons(ETH_P_8021AD):

	case htons(ETH_P_8021Q): {

		const struct vlan_hdr *vlan;



		if (skb_vlan_tag_present(skb))

			proto = skb->protocol;



		if (!skb_vlan_tag_present(skb) ||

		    proto == cpu_to_be16(ETH_P_8021Q) ||

		    proto == cpu_to_be16(ETH_P_8021AD)) {

			struct vlan_hdr _vlan;



		vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), data, hlen, &_vlan);

			vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan),

						    data, hlen, &_vlan);

			if (!vlan)

				goto out_bad;

			proto = vlan->h_vlan_encapsulated_proto;

			nhoff += sizeof(*vlan);

			if (skip_vlan)

				goto again;

		}



		skip_vlan = true;

		if (dissector_uses_key(flow_dissector,

				       FLOW_DISSECTOR_KEY_VLANID)) {

			key_tags = skb_flow_dissector_target(flow_dissector,

							     FLOW_DISSECTOR_KEY_VLANID,

							     target_container);



			if (skb_vlan_tag_present(skb))

				key_tags->vlan_id = skb_vlan_tag_get_id(skb);

			else

				key_tags->vlan_id = ntohs(vlan->h_vlan_TCI) &

					VLAN_VID_MASK;

		}



		proto = vlan->h_vlan_encapsulated_proto;

		nhoff += sizeof(*vlan);

		goto again;

	}

	case htons(ETH_P_PPP_SES): {