[LARTC] tcpdump not working with imq0 devices

[Andreas Unterkircher]

As far as I know it's simply not possible. Also you can't use iptables on a
imq device.

Cheers,
Andreas

Michal Kustosik (kustosz at veb.pl) schrieb:
>
>
> On my debian woody (kernel 2.4.31) the tcpdump
> doesn't work with imq0 devices. If I try to tcpdump
> imq devices there is no packet seen:
> [...]
> rt1:~# tcpdump -n -i imq0
>  Warning: arptype 65535 not supported by libpcap - falling back to cooked socket
>  tcpdump: WARNING: imq0: no IPv4 address assigned
>  tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
>  listening on imq0, link-type LINUX_SLL (Linux cooked), capture size 68 bytes
>
> [...]
> and there is no packet seen. I have sent the packet to imq0 by:
> rt1:~# iptables -I PREROUTING -t mangle -j IMQ --todev 0
> and there is no other entry in mangle table. There is also
> no firewall entry and no entry in nat table.
>
> The ifconfig command show, that the packet goes by imq0:
> [...]
> rt1:~# ifconfig imq0
> imq0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00
>           UP RUNNING NOARP  MTU:1500  Metric:1
>           RX packets:3268292 errors:0 dropped:0 overruns:0 frame:0
>           TX packets:3248999 errors:0 dropped:0 overruns:0 carrier:0
>           collisions:0 txqueuelen:30
>           RX bytes:1987844908 (1.8 GiB)  TX bytes:1981674079 (1.8 GiB)
> [...]
>
> Everything but iptables is installing from packages deb.
> I tried to complile TCPDUMP 3.9.4 from http://www.tcpdump.org/
> but it is the same reason.
>
> I have other router, with similar configuration (vlan, imq, htb, the
> same kernel version 2.4.31, the same distribution debian woody)
> and there is no problem with debuging interfaces by tcpdump command.
>
> Have anybody solved the same problem?
>
>
> Below some information about the strange router:
> kernel - 2.4.31 with patch-o-matic-ng, imq-nat.diff,
>          linux-2.4.28-imq2.diff,
> iptables - v1.3.3 with iptables-1.3.0-imq1.diff
> vlan - iANS-3.4.3a, e100-3.4.14
> lsmod:
> [...]
> Module                  Size  Used by    Tainted: P
> imq                     1752   1
> ipt_IMQ                  800   0
> ipt_REDIRECT             960   0  (autoclean)
> cls_fw                  2368   0  (autoclean)
> cls_u32                 4548   0  (autoclean)
> sch_sfq                 3456   0  (autoclean)
> sch_htb                19040   0  (autoclean)
> ipt_ttl                  640   0  (autoclean)
> ipt_state                608   0  (autoclean)
> ipt_REJECT              3072   0  (autoclean)
> ipt_connlimit           1504   0  (autoclean)
> ipt_LOG                 3648   0  (autoclean)
> ipt_limit                960   0  (autoclean)
> iptable_filter          1728   0  (autoclean)
> ipt_mac                  672  15  (autoclean)
> ipt_helper               992  22  (autoclean)
> ipt_multiport            640 132  (autoclean)
> ipt_MARK                 800 255  (autoclean)
> iptable_mangle          2208   1  (autoclean)
> ians                  113220   3  (autoclean)
> reiserfs              167392   1  (autoclean)
> e100                   36292   4
> ip_nat_ftp              2848   0  (unused)
> iptable_nat            22420   2  [ipt_REDIRECT ip_nat_ftp]
> ip_tables              13664  17  [ipt_IMQ ipt_REDIRECT ipt_ttl ipt_state ipt_REJECT
> ipt_connlimit ipt_LOG ipt_limit iptable_filter ipt_mac ipt_helper ipt_multiport ipt_MARK
> iptable_mangle iptable_nat]
> ip_conntrack_ftp        3872   1
> ip_conntrack           28544   1  [ipt_REDIRECT ipt_state ipt_connlimit ipt_helper
> ip_nat_ftp iptable_nat ip_conntrack_ftp]
> rtc                     6012   0  (autoclean)
> [...]
>
>
>
> Regards,
> --
> Michal Kustosik
>
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