[maybe spam] Re: linux PF_PACKET compatibility
Julian Elischer
julian at freebsd.org
Sat Feb 12 01:19:11 UTC 2011
On 2/11/11 4:03 PM, Da Rock wrote:
> On 02/12/11 02:37, Julian Elischer wrote:
>> On 2/11/11 1:36 AM, Da Rock wrote:
>>> On 02/11/11 18:17, Julian Elischer wrote:
>>>> On 2/10/11 11:22 PM, Da Rock wrote:
>>>>> "In recent versions of the Linux kernel (post-2.0 releases) a
>>>>> new protocol family has been introduced, named PF_PACKET. This
>>>>> family allows an application to send and receive packets dealing
>>>>> directly with the network card driver, thus avoiding the usual
>>>>> protocol stack-handling (e.g., IP/TCP or IP/UDP processing).
>>>>> That is, any packet sent through the socket will be directly
>>>>> passed to the Ethernet interface, and any packet received
>>>>> through the interface will be directly passed to the application."
>>>>>
>>>>> I've been chasing the answer to a FreeBSD version of this
>>>>> (approx. anyway), but I needed to find out what exactly
>>>>> PF_PACKET was first. Finally found this answer here:
>>>>> http://www.linuxjournal.com/article/4659
>>>>>
>>>>> I looked up man socket and I can see possibilities (in my mind
>>>>> anyway), but I thought I'd be best to check if the gurus here
>>>>> might have a better idea. My reason for this is I'm attempting
>>>>> to build l2tpns (which supposedly builds on 7.3?! with no
>>>>> trouble), and I'm chasing the errors which appear to be
>>>>> linuxisms mostly.
>>>>>
>>>>> So in man socket simply looking at the list of protocol families
>>>>> I'd say network driver level would be similar to PF_LINK link
>>>>> layer interface? Is there another man page I should be looking
>>>>> at as well?
>>>>
>>>> We don't have an exact equivalent.. but we have ways of doing the
>>>> same thing.
>>>> one way that is suggested is to use pcap and bpf which I am
>>>> pretty certain has been enhanced to allow sending as
>>>> well as receiving.
>>>> you can also hook directly to the interface using netgraph(4)
>>>> there are other ways too but those are the two that came to mind
>>>> immediately.
>>> So I'm going to have to rewrite that interface entirely? Bugger! I
>>> just can't fathom how this howto could even exist for l2tpns on
>>> FreeBSD if it isn't even close to buildable... weird!
>>>
>>> http://kuapp.com/2010/07/14/how-to-setup-l2tpipsec-vpn-on-freebsd.html
>>>
>>>
>>> Thanks guys. I'll probably come back with more problems as I
>>> slowly crack this one... :)
>>
>>
>> nothing in that page needs to talk to the network interface
>> directly... what do you think does?
> I'm afraid you have me a little stumped. The PF_PACKET family talks
> directly with the network driver sending data to and from the app.
>
> Unfortunately this software uses this family instead of pcap or bpf.
> So when built it errors.
>
> I guess if I am to use this app I will have to rewrite the way it
> uses the network stack.
l2tp runs over UDP packets (port 1701 (like the starship enterprise))
I have no idea why they want raw packets.
talk to the writer of the web page you indicated.. maybe he can help..
>>
>>
>>
>>>>
>>>>
>>>>>
>>>>> FWIW my gmake output is this:
>>>>>
>>>>> gcc -Wall -Wformat-security -Wno-format-zero-length -g -O3 -I.
>>>>> -I/usr/include -I/usr/local/include -DLIBDIR='"/lib/l2tpns"'
>>>>> -DETCDIR='"/etc/l2tpns"' -DSTATISTICS -DSTAT_CALLS -DRINGBUFFER
>>>>> -DHAVE_EPOLL -DBGP -c -o arp.o arp.c
>>>>> arp.c: In function 'sendarp':
>>>>> arp.c:34: error: storage size of 'sll' isn't known
>>>>> arp.c:59: error: 'PF_PACKET' undeclared (first use in this
>>>>> function)
>>>>> arp.c:59: error: (Each undeclared identifier is reported only once
>>>>> arp.c:59: error: for each function it appears in.)
>>>>> arp.c:62: error: 'AF_PACKET' undeclared (first use in this
>>>>> function)
>>>>> arp.c:34: warning: unused variable 'sll'
>>>>> gmake: *** [arp.o] Error 1
>>>>>
>>>>> I posted this over at -questions@ but it was suggested to try
>>>>> here instead (or -net@). I figured this would be the best place
>>>>> to start... :)
>>>>>
>>>>> Cheers
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>>>>>
>>>>
>>>
>>>
>>
>
>
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