Re: [lwip-users] Force PPP TermReq (Lwip 2.0.0 RC2)

[Sylvain Rochet]

Hi Greg,


On Wed, Aug 10, 2016 at 03:56:43PM +0000, Greg Smith wrote:
> 
> At the very bottom is a clip with some sample output I get during 
> connecting and


> reception of a couple TCP keepalive packets.  (The keepalive seems to 
> print the packet data.)

This is a bug, packet trace is meant to only display packets that are 
useful to diagnose a PPP link establishment. IPv4, IPv6, VJ comp/uncomp, 
Compressed packet are data packets which are just passing through PPP 
layers without having any effect on the PPP state machine.


> But I don't see any lines showing raw data going out (or, generally, 
> coming in, either). (Ignore the missing data at the end of the line 
> with TCP_KEEPINTV; that's a function of my output capture.)

Yes, that's expected :-), if you want to see everything, comment the 
filtering rules in the ppp_dump_packet function.


> How do you get pppd to print out packets?  I've turned on pppd 
> 'debug', but that doesn't give me packet data, either.  I see the sent 
> and rcvd LCP packet high level information, but not actual packet data 
> for any further transmissions (i.e. the TCP keepalive, for instance).

Yes, that's still expected, pppd does the same, in fact, in the case of 
pppd, data packets (IPv4, IPv6, VJ, Compressed) are never leaving the 
kernel so the pppd process doesn't receive them at all.


> And when I get into the state where pppd seems to being ignore LCP 
> packets, I do not get anything from pppd.

That's not normal, even if pppd would ignore the LCP packet for any 
reason, it should at least display it with the debug option enabled. 
Same for lwIP. What is filtered though are LCP echo request/reply 
packets, because they are mostly useless in the packet trace.


Sylvain

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