From 36b2f61a42c29add695f3bd192ce44d5c113c1eb Mon Sep 17 00:00:00 2001
From: Govindarajulu Varadarajan <gvaradar@cisco.com>
Date: Fri, 14 Jun 2019 06:13:54 -0700
Subject: [PATCH] net: handle 802.1P vlan 0 packets properly
When stack receives pkt: [802.1P vlan 0][802.1AD vlan 100][IPv4],
vlan_do_receive() returns false if it does not find vlan_dev. Later
__netif_receive_skb_core() fails to find packet type handler for
skb->protocol 801.1AD and drops the packet.
801.1P header with vlan id 0 should be handled as untagged packets.
This patch fixes it by checking if vlan_id is 0 and processes next vlan
header.
Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/core/dev.c | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index eb7fb6daa1ef..d6edd218babd 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4923,8 +4923,36 @@ skip_classify:
}
if (unlikely(skb_vlan_tag_present(skb))) {
- if (skb_vlan_tag_get_id(skb))
+check_vlan_id:
+ if (skb_vlan_tag_get_id(skb)) {
+ /* Vlan id is non 0 and vlan_do_receive() above couldn't
+ * find vlan device.
+ */
skb->pkt_type = PACKET_OTHERHOST;
+ } else if (skb->protocol == cpu_to_be16(ETH_P_8021Q) ||
+ skb->protocol == cpu_to_be16(ETH_P_8021AD)) {
+ /* Outer header is 802.1P with vlan 0, inner header is
+ * 802.1Q or 802.1AD and vlan_do_receive() above could
+ * not find vlan dev for vlan id 0.
+ */
+ __vlan_hwaccel_clear_tag(skb);
+ skb = skb_vlan_untag(skb);
+ if (unlikely(!skb))
+ goto out;
+ if (vlan_do_receive(&skb))
+ /* After stripping off 802.1P header with vlan 0
+ * vlan dev is found for inner header.
+ */
+ goto another_round;
+ else if (unlikely(!skb))
+ goto out;
+ else
+ /* We have stripped outer 802.1P vlan 0 header.
+ * But could not find vlan dev.
+ * check again for vlan id to set OTHERHOST.
+ */
+ goto check_vlan_id;
+ }
/* Note: we might in the future use prio bits
* and set skb->priority like in vlan_do_receive()
* For the time being, just ignore Priority Code Point