FT-EAP hostapd - AP to AP packets lost

[Mikael Kanstrup]

Hi Jouni and all,

I am trying to setup FT-EAP with hostapd but struggle to have AP to AP 
communication working. RRB packets are not received properly without 
patching hostapd sources.

The setup is using two D-Link DWA-160 adapters (rt2800usb driver) each 
on a separate instance of hostapd. The wireless interfaces are bridged 
using the 'bridge' hostapd configuration option. I'm using Ubuntu 16.04 
with HWE stack (kernel 4.8.0-41-generic).

Up until yesterday I was running with the "old" FT RRB protocol (hostapd 
version from git 87ad672) and today I just tried with Michael's FT 
improvement patches applied (942b52a) and the cause of problems seems 
the be the same.

I can successfully connect to either AP but roaming is not working. 
Using Wireshark to trace both the bridge interface and each wireless 
interface I can see the RRB packets (for PMK R1 pull request) being sent 
but for some reason not received properly. Not by any of the AP instances.

If I apply the following patch (to receive all ethernet frames) I can 
connect and roam back and forth between the two APs with the old RRB 
protocol:

diff --git a/src/ap/wpa_auth_glue.c b/src/ap/wpa_auth_glue.c
index 9bd07c8..5ff6c63 100644
--- a/src/ap/wpa_auth_glue.c
+++ b/src/ap/wpa_auth_glue.c
@@ -633,6 +633,9 @@ static void hostapd_rrb_receive(void *ctx, const u8 
*src_addr, const u8 *buf,
         if (len < sizeof(*ethhdr))
                 return;
         ethhdr = (struct l2_ethhdr *) buf;
+       if (be_to_host16(ethhdr->h_proto) != ETH_P_RRB) {
+               return;
+       }
         wpa_printf(MSG_DEBUG, "FT: RRB received packet " MACSTR " -> "
                    MACSTR, MAC2STR(ethhdr->h_source), 
MAC2STR(ethhdr->h_dest));
         if (!is_multicast_ether_addr(ethhdr->h_dest) &&
@@ -715,7 +718,7 @@ int hostapd_setup_wpa(struct hostapd_data *hapd)
             wpa_key_mgmt_ft(hapd->conf->wpa_key_mgmt)) {
                 hapd->l2 = l2_packet_init(hapd->conf->bridge[0] ?
hapd->conf->bridge :
- hapd->conf->iface, NULL, ETH_P_RRB,
+ hapd->conf->iface, NULL, ETH_P_ALL,
                                           hostapd_rrb_receive, hapd, 1);
                 if (hapd->l2 == NULL &&
                     (hapd->driver == NULL ||


For hostapd with new RRB protocol the hostapd_rrb_oui_receive handler is 
not called until I change to ETH_P_ALL (in eth_p_oui_register).

Any clue why packets are received only when listening to all ethernet 
frames?


My config files provided below for reference

old FT hostapd.conf used on both APs:
driver=nl80211
ssid=Kanstrup-FT-EAP
channel=1
ieee80211n=1
ht_capab=[SHORT-GI-20]
hw_mode=g
ctrl_interface=/var/run/hostapd
ctrl_interface_group=adm
eap_server=1
eap_user_file=peap-mschapv2.eap_user
eap_reauth_period=600
wpa=2
wpa_pairwise=CCMP
ieee8021x=1
server_cert=server.pem
private_key=server.key
bridge=br0
wpa_key_mgmt=FT-EAP
mobility_domain=0102
ft_over_ds=1
r1_key_holder=9cd643e7bb68
nas_identifier=ft-eap-9cd643e7bb68
r0kh=9c:d6:43:e7:bb:68 ft-eap-9cd643e7bb68 f8840e8cd41fb3653bd88f64c203349f
r1kh=9c:d6:43:e7:bb:68 9c:d6:43:e7:bb:68 f8840e8cd41fb3653bd88f64c203349f
r1kh=9c:d6:43:e7:bb:a4 9c:d6:43:e7:bb:a4 f8840e8cd41fb3653bd88f64c203349f

new FT hostapd.conf used on both APs:
driver=nl80211
ssid=Kanstrup-FT-EAP
channel=1
ieee80211n=1
ht_capab=[SHORT-GI-20]
hw_mode=g
#require_ht=1
ignore_broadcast_ssid=0
ctrl_interface=/var/run/hostapd
ctrl_interface_group=adm
eap_server=1
eap_user_file=peap-mschapv2.eap_user
eap_reauth_period=600
wpa=2
wpa_pairwise=CCMP
ieee8021x=1
server_cert=server.pem
private_key=server.key
bridge=br0
wpa_key_mgmt=FT-EAP
mobility_domain=0102
ft_over_ds=1
nas_identifier=kanstrup.test.test
r0kh=ff:ff:ff:ff:ff:ff * 00112233445566778899aabbccddeeff
r1kh=00:00:00:00:00:00 00:00:00:00:00:00 00112233445566778899aabbccddeeff


Best Regards
Mikael Kanstrup