I am attempting to setup a dualstack interface on Verizon with the MC7354 using libqmi and the Linux kernel 3.13 qmi_wwan driver. Independently, IPv4 and IPv6 work successfully using DHCP for v4 and SLAAC for v6. I can bring up both WDS clients and successfully start both network calls. I enable the net-802-3 and net-no-qos-header options to qmicli. The modem is using the latest VzW software: SWI9X15C_05.05.16.03 r22385
The problem arises when doing a simple ping on IPv6 after DHCP has been started. If I simply start both networks, perform the IPv6 autoconfiguration, and ping 2607:f8b0:4004:806::1005 (google.com), the ping succeeds. After starting DHCP, the ping response has a garbled 802.3 header. The MAC address and ethernet type fields are invalid as shown in the following tcpdump output. The data in the packet is correct but the header prevents interpretation by the software. IPv4 continues to be usable after IPv6 gets into this state.
09:09:07.027155 3e:3a:cf:a5:18:52 2:50:f3:0:8:0 86dd 118: 2600:1009:b023:940:3c3a:cfff:fea5:1852 > 2607:f8b0:4004:806::1005: icmp6: echo request
0x0000 6000 0000 0040 3aff 2600 1009 b023 0940 ....@:.&....#.@ 0x0010 3c3a cfff fea5 1852 2607 f8b0 4004 0806 <:.....R&...@... 0x0020 0000 0000 0000 1005 8000 4db5 07bb 0016 ..........M..... 0x0030 f05c b03b 0000 0000 0000 0000 0000 0000 .\.;............ 0x0040 0000 0000 0000 0000 0000 0000 0000 0000 ................ 0x0050 0000 .. 09:09:07.133879 eb:b8:7:63:95:27 fb:d7:2b:6a:0:45 f60c 118: 0x0000 6000 0000 0040 3a32 2607 f8b0 4004 0806
…@:2&…@…
0x0010 0000 0000 0000 1005 2600 1009 b023 0940 …&…#.@
0x0020 3c3a cfff fea5 1852 8100 4cb5 07bb 0016 <:…R…L…
0x0030 f05c b03b 0000 0000 0000 0000 0000 0000 …;…
0x0040 0000 0000 0000 0000 0000 0000 0000 0000 …
0x0050 0000 …
Any help?