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Date:      Mon, 4 May 2020 13:08:40 -0700
From:      Adrian Chadd <adrian@freebsd.org>
To:        Cy Schubert <cy@freebsd.org>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>,  freebsd-wireless <freebsd-wireless@freebsd.org>
Subject:   Re: svn commit: r355988 - in head: contrib/libpcap contrib/libpcap/cmake/Modules contrib/libpcap/doc contrib/libpcap/missing contrib/libpcap/msdos contrib/libpcap/pcap contrib/libpcap/rpcapd contrib/li...
Message-ID:  <CAJ-Vmom%2B=8kxpCruTM7mvjBWMax5oFGt6rz02pvgHwonpjMzYA@mail.gmail.com>
In-Reply-To: <CAJ-VmomJKAW7UrpDR-gmR_OHQJem%2BQgu1i%2BCcLrRgXpNDvmdRA@mail.gmail.com>
References:  <201912212101.xBLL14sr033938@repo.freebsd.org> <CAJ-VmomJKAW7UrpDR-gmR_OHQJem%2BQgu1i%2BCcLrRgXpNDvmdRA@mail.gmail.com>

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On Mon, 4 May 2020 at 12:54, Adrian Chadd <adrian@freebsd.org> wrote:
>
> hi,
>
> This commit /seems/ to have broken things on FreeBSD-HEAD on mips74k.
> I haven't yet tried hostapd mode on x86 with this commit; I"ll do that
> soon.
>
> The TL;DR:
>
> * hostapd + wpa encryption + mips32 (mips74k in this instance) fails
> on -HEAD! Woo!
>
> * l2_packet_freebsd.c in hostapd uses a pcap filter to filter out
> eapol frames from other parties to the eapol/raw receive socket;
> * the filter compilation causes an unaligned access on mips, which i
> /thought/ we handled correctly, but apparently not;
> * the filter as written in hostapd doesn't result in anything being received.
>
> The unaligned warn is:
>
> Unaligned Load Word: pid=426 (tcpdump), tid=100040, pc=0x40569034,
> badvaddr=0x4051d02a
>
> (I dno't yet have the line of code, that's next too.)
>
> The filter is:
>
> *** Filter is "not ether src c4:6e:1f:5b:04:f7 and ( ether dst
> c4:6e:1f:5b:04:f7 or ether dst 01:80:c2:00:00:03 ) and ether proto
> 0x888e"
>
> I'll dig into the details some more soon.
>

Here's an example EAPOL exchange with a minimal filter:

# tcpdump -l -ni wlan0 -y IEEE802_11_RADIO -vvvv -eeee "(ether proto 0x888e)"
tcpdump: data link type IEEE802_11_RADIO
tcpdump: listening on wlan0, link-type IEEE802_11_RADIO (802.11 plus
radiotap header), capture size 262144 bytes
19:58:39.880399 1.0 Mb/s 60dBm tx power antenna 0 2412 MHz 11g ht/20
0us DA:00:03:7f:40:82:1a BSSID:c4:6e:1f:5b:04:f7 SA:c4:6e:1f:5b:04:f7
LLC, dsap SNAP (0xaa) Individual, ssap SNAP (0xaa) Command, ctrl 0x03:
oui Ethernet (0x000000), ethertype EAPOL (0x888e), length 99: EAPOL
key (3) v2, len 95
19:58:39.885193 846271791us tsft 1.0 Mb/s -29dBm signal -96dBm noise
antenna 1 2412 MHz 11g 314us BSSID:c4:6e:1f:5b:04:f7
SA:00:03:7f:40:82:1a DA:c4:6e:1f:5b:04:f7 LLC, dsap SNAP (0xaa)
Individual, ssap SNAP (0xaa) Command, ctrl 0x03: oui Ethernet
(0x000000), ethertype EAPOL (0x888e), length 121: EAPOL key (3) v1,
len 117
19:58:39.886907 1.0 Mb/s 60dBm tx power antenna 0 2412 MHz 11g ht/20
0us DA:00:03:7f:40:82:1a BSSID:c4:6e:1f:5b:04:f7 SA:c4:6e:1f:5b:04:f7
LLC, dsap SNAP (0xaa) Individual, ssap SNAP (0xaa) Command, ctrl 0x03:
oui Ethernet (0x000000), ethertype EAPOL (0x888e), length 203: EAPOL
key (3) v2, len 199
19:58:39.892254 846278862us tsft 1.0 Mb/s -32dBm signal -96dBm noise
antenna 1 2412 MHz 11g 314us BSSID:c4:6e:1f:5b:04:f7
SA:00:03:7f:40:82:1a DA:c4:6e:1f:5b:04:f7 LLC, dsap SNAP (0xaa)
Individual, ssap SNAP (0xaa) Command, ctrl 0x03: oui Ethernet
(0x000000), ethertype EAPOL (0x888e), length 99: EAPOL key (3) v1, len
95

Note it's between 00:03:7f:40:82:1a (the STA) and c4:6e:1f:5b:04:f7
(the AP). If I add the ether dst clause - either half - I get nothing.

Any ideas? :) I can chop the filter down to EAPOL only for now to save
on AP CPU but I'd love to get to the root cause and fix it in -HEAD
and -12.

Thanks!


-adrian

> Thanks,
>
>
>
> -adrian
>
>
> On Sat, 21 Dec 2019 at 13:01, Cy Schubert <cy@freebsd.org> wrote:
> >
> > Author: cy
> > Date: Sat Dec 21 21:01:03 2019
> > New Revision: 355988
> > URL: https://svnweb.freebsd.org/changeset/base/355988
> >
> > Log:
> >   MFV r353141 (by phillip):
> >
> >   Update libpcap from 1.9.0 to 1.9.1.
> >
> >   MFC after:    2 weeks



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