#17625: destination mac address of IPv6 neighbour solicitation changed from
multi-
to unicast (IPv6 partly broken)
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Reporter: elpeh | Owner: developers
Type: defect | Status: new
Priority: high | Milestone: Barrier Breaker 14.07
Component: kernel | Version: Barrier Breaker 14.07
Keywords: bridge multicast IPv6 NDP |
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Hello,
with 14.07rc3 I see the following misbehaviour on openwrt-ar71xx-generic-
tl-wr710n-v1... This (IPv6 partly broken) was not the case with some
earlier BB snapshot on that device and (as shown later) AA on WRT160NL.
Effect: IPv6 is not working reliably for a Linux VM in VMware Fusion on
Macbook, connected by WLAN (Ethernet not tested yet). If OpenWRT has to
send NDP neighbour solicitation packets those do not reach the VM (that
means IPv6 connectivity for the VM only works if one e.g. ping6s the
gateway/OpenWRT first).
VMware Fusion is doing some MAC address NAT for bridged interfaces with
WLAN(?). Guest MAC addresses are replaced by address of host interface.
IPv6 Neighbour solicitation frames are sent to muliticast group and
multicast MAC address. At laest this is also what tcpdump br-lan shows on
OpenWRT:
07:53:15.267516 64:66:b3:85:15:c9 > 33:33:ff:6a:67:2f, ethertype IPv6
(0x86dd), length 86: (hlim 255, next-header ICMPv6 (58) payload length:
32) fde9:9177:dccc:8::1 > ff02::1:ff6a:672f: [icmp6 sum ok] ICMP6,
neighbor solicitation, length 32, who has
fde9:9177:dccc:8:20c:29ff:fe6a:672f
source link-address option (1), length 8 (1): 64:66:b3:85:15:c9
BUT: this is received on WLAN interface of Mac (host system):
09:53:15.273459 64:66:b3:85:15:c9 (oui Unknown) > b8:8d:12:18:31:e4 (oui
Unknown), ethertype IPv6 (0x86dd), length 86: (hlim 255, next-header
ICMPv6 (58) payload length: 32) fde9:9177:dccc:8::1 > ff02::1:ff6a:672f:
[icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has
fde9:9177:dccc:8:20c:29ff:fe6a:672f
source link-address option (1), length 8 (1): 64:66:b3:85:15:c9
33:33:ff:6a:67:2f has been replaced by b8:8d:12:18:31:e4 somewhere.
Somewhere within OpenWRT 14.07rc3 that is, because it happens only in this
setup.
With earlier version (see above) the destinations address stays multicast.
VMware Fusion does not/cannot pass a frame with hardware address of Mac
WLAN interface as destination to the Linux VM -> IPv6 for VM is broken...
What's going on here? Trying to optimize something? Please revert the
change.
Thanks for your work,
Lutz
--
Ticket URL: <https://dev.openwrt.org/ticket/17625>
OpenWrt <http://openwrt.org>
Opensource Wireless Router Technology
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