IPSP ping fails


Issue with IPSP sample (recent master branch) : Ping fails. 

BLE address is assigned to k64f board. bluetoothctl utility and its scan discover IPSP node.
BLE connection is up, interface bt0 is up.
On zephyr side, iface shows interface bluetooth.

Ping to k64f board fails. Ping from Zephyr side to Linux host fails.
Wireshark capture shows checksum error (checksum incorrect) for ICMPv6 packet.

$ ping6 2001:db8::1
PING 2001:db8::1(2001:db8::1) 56 data bytes
--- 2001:db8::1 ping statistics ---
4 packets transmitted, 0 received, 100% packet loss, time 2999ms



net> ping 2001:db8::2
Sent a ping to 2001:db8::2
Ping timeout

Test set up for IPv6 over BLE :

[Kw41z (ble controller)+ k64f (zephyr IPSP)] <---------->[Kw41z (ble controller)+Linux host]

At one end : Two boards frdm-kw41z and frdm-k64f are stacked together.
kw41z (flashed with hci_blackbox firmware) is ble controller with k64f as ble host (flashed with zephyr sample IPSP).

$ sudo minicom -s -D /dev/ttyACMx -b 115200

[bt] [WRN] set_flow_control: Controller to host flow control not supported
[bt] [INF] show_dev_info: Identity: 00:04:9f:00:00:15 (public)
[bt] [INF] show_dev_info: HCI: version 4.2 (0x08) revision 0x000b, manufacturer 0x0025
[bt] [INF] show_dev_info: LMP: version 4.2 (0x08) subver 0x0121
[ipsp] [INF] init_app: Run IPSP sample
[ipsp] [INF] listen: Starting to wait

net> iface

Interface 0x20009f40 (Bluetooth)

Link addr : 00:04:9F:00:00:15
MTU : 1280
IPv6 unicast addresses (max 3):
2001:db8::1 manual preferred infinite
fe80::4:9fff:fe00:15 autoconf preferred infinite
IPv6 multicast addresses (max 2):
IPv6 prefixes (max 2):

IPv6 hop limit : 64
IPv6 base reachable time : 30000
IPv6 reachable time : 21690
IPv6 retransmit timer : 0

net> nbr

Neighbor Interface Flags State Remain Link Address
[ 1] 0x20009418 0x20009f40 0/1/0/1 static 0 00:60:37:00:00:16 fe80::60:37ff:fe00:16

At the other end: Second kw41z (flashed with hci_blackbox firmware) is ble controller attached to Linux host.

$ sudo hciattach ttyACMy any 115200 noflow sleep (in Linux terminal)

$ sudo hcitool lecc 00:04:9f:00:00:15
Connection handle 32

$ sudo hcitool conn
< LE 00:04:9F:00:00:15 handle 32 state 1 lm MASTER

$ sudo hcitool dev
hci0 00:60:37:00:00:16

$ bluetoothctl
[NEW] Controller 00:60:37:00:00:16 nxa15861-1704 [default]
[NEW] Device 00:04:9F:00:00:15 Test IPSP node
[NEW] Device 00:60:37:00:00:16 Test IPSP node
[CHG] Device 00:04:9F:00:00:15 Connected: yes
[Test IPSP node]#

$ ifconfig bt0

bt0 Link encap:UNSPEC HWaddr 00-60-37-FF-FE-00-00-16-00-00-00-00-00-00-00-00
inet6 addr: fe80::260:37ff:fe00:16/64 Scope:Link
inet6 addr: 2001:db8::2/64 Scope:Global
RX packets:9 errors:0 dropped:0 overruns:0 frame:0
TX packets:16 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1
RX bytes:419 (419.0 B) TX bytes:882 (882.0 B)

conf options addition to prj.conf