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Ticket #2029 (new defect)

Opened 14 years ago

Last modified 14 years ago

Malformed packets in DHCP challenge

Reported by: Assigned to:
Priority: major Milestone:
Component: madwifi: other Version: trunk
Keywords: Cc:
Patch is attached: 0 Pending:


I have an Atheros card in master mode, encryption is off; the client is a Nokia E51 Symbian phone.
Some specific packets get mangled in the DHCP challenge, which does not succeed. When i use a standard AP configured as bridge instead of the Atheros card no broken packet appears. I attached tcpdumps of the challenges against Madwifi and the Asus AP as reference.
SVN revision is 3746, kernel (Ubuntu).
I tried to disable wmm, uapsd, ff and burst mode, without any effect.

# lspci

00:14.0 Ethernet controller: Atheros Communications Inc. AR5212/AR5213 
Multiprotocol MAC/baseband processor (rev 01)

# dmesg

[294740.770000] AR5210, AR5211, AR5212, AR5416, RF5111, RF5112, RF2413, 
RF5413, RF2133)
[294740.820000] ACPI: PCI Interrupt 0000:00:14.0[A] -> Link [LNKB] -> 
GSI 10 (level, low) -> IRQ 10
[294741.410000] MadWifi: ath_attach: Switching rfkill capability off.
[294741.430000] wifi0: Atheros AR2414 chip found (MAC 7.9, PHY 2112A 
4.5, Radio 5.6)
[294741.450000] ath_pci: wifi0: Atheros 5212: mem=0xde000000, irq=10


madwifi.pcap (7.0 kB) - added by on 07/05/08 09:48:20.
tcpdump of the madwifi conversation
asusap.pcap (2.1 kB) - added by on 07/05/08 09:49:13.
tcpdump conversation with a working AP

Change History

07/05/08 09:48:20 changed by

  • attachment madwifi.pcap added.

tcpdump of the madwifi conversation

07/05/08 09:49:13 changed by

  • attachment asusap.pcap added.

tcpdump conversation with a working AP

08/08/08 18:49:54 changed by anonymous

Hi I've a similar problem. I set the madwifi card into ap mode, no encryption and dnsmasq runs as dhcp server on ath0. Only the first connection from my E51 is successful and it receives a DHCP address from dnsmasq. When I try to reconnect to ath0 from the Nokia E51 it doesn't obtain a DHCP address anymore. I have to destroy and recreate the VAP before the Nokia E51 obtains a DHCP Adress again.

@matteo have you already found a solution for that problem?

regards, ruben

08/12/08 12:44:19 changed by

No solution up to now. I noticed that when the phone browser request an IP the DHCP handshake succeeds. So to use the SIP client, i first fire the browser, then start the SIP connection. There are still lost packets, but sometime it works.