From f90615ada0b1e21a9d93ff89b04549fd7a92c92b Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 21 Apr 2023 01:55:53 +0300 Subject: [PATCH] net: vlan: don't adjust MAC header in __vlan_insert_inner_tag() unless set This is a preparatory change for the deletion of skb_reset_mac_header(skb) from __dev_queue_xmit(). After that deletion, skb_mac_header(skb) will no longer be set in TX paths, from which __vlan_insert_inner_tag() can still be called (perhaps indirectly). If we don't make this change, then an unset MAC header (equal to ~0U) will become set after the adjustment with VLAN_HLEN. Signed-off-by: Vladimir Oltean Reviewed-by: Eric Dumazet Reviewed-by: Simon Horman Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- include/linux/if_vlan.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index 6864b89ef8681..90b76d63c11c2 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -351,7 +351,8 @@ static inline int __vlan_insert_inner_tag(struct sk_buff *skb, /* Move the mac header sans proto to the beginning of the new header. */ if (likely(mac_len > ETH_TLEN)) memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN); - skb->mac_header -= VLAN_HLEN; + if (skb_mac_header_was_set(skb)) + skb->mac_header -= VLAN_HLEN; veth = (struct vlan_ethhdr *)(skb->data + mac_len - ETH_HLEN); -- 2.30.2