DHCP over WiFi issues on RPI

[Jason Thorpe <thorpej%me.com@localhost>]

Howdy folks —

I’m setting up a RPI to use in an absurd sort of IoT project, but I’m having trouble getting DHCP working.

The WiFi infrastructure in my house is a Ubiquiti system, and I had no problem getting wpa_supplicant set up:

urtwn0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        ssid **redacted** nwkey **redacted**
        powersave off
        bssid 80:2a:a8:57:72:70 chan 1
        address: 40:a5:ef:dc:4e:46
        media: IEEE802.11 autoselect (OFDM54 mode 11g)
        status: active
        inet6 fe80::42a5:efff:fedc:4e46%urtwn0/64 flags 0x0 scopeid 0x2
        inet 169.254.19.109/16 broadcast 169.254.255.255 flags 0x0

…but as you can see, I appear stuck with an IPv4LL address.

Watching the network from my Mac, I can see the RPI sending out DHCP requests, and I can see my router replying:

23:05:20.107550 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46, length 343
23:05:21.132197 IP 192.168.1.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 544
23:06:24.722230 IP 192.168.1.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 544
23:08:33.030025 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46, length 343
23:12:50.466054 IP 192.168.1.254.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 544

…but the RPI never seems to see the reply:

15:44:56.593037 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:46:00.722164 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:47:04.242281 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:48:08.312707 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:49:12.412273 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:50:17.162762 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:51:20.571510 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343
15:52:25.461653 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from 40:a5:ef:dc:4e:46 (oui Unknown), length 343

Using Wireshark to peek at the details the Discover and the Offer look legit .. transaction IDs match, etc.  The Offer has the address of 192.168.1.100.  The Offers are being sent to IP / Ethernet broadcast (255.255.255.255 / ff:ff:ff:ff:ff:ff), but the Offer message itself has the correct matching client information.

Ideas?

Thx.

-- thorpej