From b22aae410bc7e4e9a6b43e556dc34be72deadb65 Mon Sep 17 00:00:00 2001 From: Zhenlei Huang Date: Wed, 30 Aug 2023 17:36:38 +0800 Subject: [PATCH] net: Remove vlan metadata on pcp / vlan encapsulation For oubound traffic, the flag M_VLANTAG is set in mbuf packet header to indicate the underlaying interface do hardware VLAN tag insertion if capable, otherwise the net stack will do 802.1Q encapsulation instead. Commit 868aabb4708d introduced per-flow priority which set the priority ID in the mbuf packet header. There's a corner case that when the driver is disabled to do hardware VLAN tag insertion, and the net stack do 802.1Q encapsulation, then it will result double tagged packets if the driver do not check the enabled capability (hardware VLAN tag insertion). Unfortunately some drivers, currently known cxgbe(4) re(4) ure(4) igc(4) and vmx(4), have this issue. From a quick review for other interface drivers I believe a lot more drivers have the same issue. It makes more sense to fix in net stack than to try to change every single driver. PR: 270736 Reviewed by: kp Fixes: 868aabb4708d Add IP(V6)_VLAN_PCP to set 802.1 priority per-flow MFC after: 1 week Differential Revision: https://reviews.freebsd.org/D39499 --- sys/net/if_ethersubr.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c index 63ea5e7591c..ab274eeb88b 100644 --- a/sys/net/if_ethersubr.c +++ b/sys/net/if_ethersubr.c @@ -446,9 +446,11 @@ ether_set_pcp(struct mbuf **mp, struct ifnet *ifp, uint8_t pcp) struct ether_header *eh; eh = mtod(*mp, struct ether_header *); - if (ntohs(eh->ether_type) == ETHERTYPE_VLAN || - ntohs(eh->ether_type) == ETHERTYPE_QINQ) + if (eh->ether_type == htons(ETHERTYPE_VLAN) || + eh->ether_type == htons(ETHERTYPE_QINQ)) { + (*mp)->m_flags &= ~M_VLANTAG; return (true); + } qtag.vid = 0; qtag.pcp = pcp; @@ -1463,6 +1465,7 @@ ether_8021q_frame(struct mbuf **mp, struct ifnet *ife, struct ifnet *p, if_printf(ife, "unable to prepend 802.1Q header"); return (false); } + (*mp)->m_flags &= ~M_VLANTAG; } return (true); }