Bug 27567

On VLANs configured on ti0 (Netgear GA620), specific packets are lost to receive. In my case, Cabletron/Enterasys SSR8000 L3 Switch's ARP request and ARP reply to the FreeBSD box can not be received always, as long as tcpdump said.
I checked if_ti.c and if_vlan.c, inserting debug messages, and found that, when receiving these problematic packets, VLAN tag is > 4095. As IEEE 802.1Q said, VLAN tag field is 12bit wide, so this is not good.
Lower 12 bit of the VLAN tag is correct, so I patched to mask. Works great!

I don't know why upper 4 bits of the VLAN tag are set, because I can't find source code of Tigon firmware, but suppose that priority field of 802.1Q VLAN packet may cause this problem.

Fix: Patch bellow will fix the problem. I don't know if sending side need masking or not.



@@ -2106,7 +2106,7 @@
 #if NVLAN > 0
                        if (ifv != NULL) {
                                f->ti_flags |= TI_BDFLAG_VLAN_TAG;
-                               f->ti_vlan_tag = ifv->ifv_tag;
+                               f->ti_vlan_tag = ifv->ifv_tag & 0xfff;
                        } else {
                                f->ti_vlan_tag = 0;
                        }--xRwBkwnwHS2V7xRROgVQMQ0IDlC47IzKMyzKAyEuZFVKOA0P
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--- pci/if_ti.c.dist    Thu Aug 24 09:07:58 2000
+++ pci/if_ti.c Wed May 23 11:54:47 2001
@@ -1846,7 +1846,7 @@
 #if NVLAN > 0
                if (cur_rx->ti_flags & TI_BDFLAG_VLAN_TAG) {
                        have_tag = 1;
-                       vlan_tag = cur_rx->ti_vlan_tag;
+                       vlan_tag = cur_rx->ti_vlan_tag & 0xfff;
                }
 #endif
How-To-Repeat: Said above.