About 802.1Q tag

[Kohji Okuno]

Hi,

Would someone check the following code?

If the hardware do not process an 802.1Q tag, the kernel repacks mbuf
in line 578-580. But, `struct ether_header *eh' was assigned at line 484.

And, in line 611-637, because of the kernel refers old eh pointer, the
kernel will misjudges its ether packet.

I think that `eh = mtod(m, struct ether_header *);' is needed after
line 580.

Thanks,
 Kohji Okuno

sys/net/if_ethersubr.c:
448	static void
449	ether_input_internal(struct ifnet *ifp, struct mbuf *m)
450	{
451	        struct ether_header *eh;

484	        eh = mtod(m, struct ether_header *);

554	        /*
555	         * If the hardware did not process an 802.1Q tag, do this now,
556	         * to allow 802.1P priority frames to be passed to the main input
557	         * path correctly.
558	         * TODO: Deal with Q-in-Q frames, but not arbitrary nesting levels.
559	         */
560	        if ((m->m_flags & M_VLANTAG) == 0 && etype == ETHERTYPE_VLAN) {
	
578	                bcopy((char *)evl, (char *)evl + ETHER_VLAN_ENCAP_LEN,
579	                    ETHER_HDR_LEN - ETHER_TYPE_LEN);
580	                m_adj(m, ETHER_VLAN_ENCAP_LEN);
581	        }

610	
611	#if defined(INET) || defined(INET6)
612	        /*
613	         * Clear M_PROMISC on frame so that carp(4) will see it when the
614	         * mbuf flows up to Layer 3.
615	         * FreeBSD's implementation of carp(4) uses the inprotosw
616	         * to dispatch IPPROTO_CARP. carp(4) also allocates its own
617	         * Ethernet addresses of the form 00:00:5e:00:01:xx, which
618	         * is outside the scope of the M_PROMISC test below.
619	         * TODO: Maintain a hash table of ethernet addresses other than
620	         * ether_dhost which may be active on this ifp.
621	         */
622	        if (ifp->if_carp && (*carp_forus_p)(ifp, eh->ether_dhost)) {
623	                m->m_flags &= ~M_PROMISC;
624	        } else
625	#endif
626	        {
627	                /*
628	                 * If the frame received was not for our MAC address, set the
629	                 * M_PROMISC flag on the mbuf chain. The frame may need to
630	                 * be seen by the rest of the Ethernet input path in case of
631	                 * re-entry (e.g. bridge, vlan, netgraph) but should not be
632	                 * seen by upper protocol layers.
633	                 */
634	                if (!ETHER_IS_MULTICAST(eh->ether_dhost) &&
635	                    bcmp(IF_LLADDR(ifp), eh->ether_dhost, ETHER_ADDR_LEN) != 0)
636	                        m->m_flags |= M_PROMISC;
637	        }