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Re: [lwip-devel] Missing initialization somewhere?


From: Sergey Kubushyn
Subject: Re: [lwip-devel] Missing initialization somewhere?
Date: Thu, 13 Oct 2011 10:28:14 -0700 (PDT)
User-agent: Alpine 2.02 (LFD 1266 2009-07-14)

On Thu, 13 Oct 2011, address@hidden wrote:

Sergey Kubushyn wrote:
The netif is UP and running. If the first packet after reset is ICMP it
keeps running forever. If the first packet after reset is TCP SYN it
_sometimes_ (something like every second reset) makes that netif->flags to
drop its UP flag. If an ICMP packet is in/out (echo req/rply) is processed
before the first TCP SYN everything work fine every time, no failures.

Hmm, that sounds like some pointer running wild and writing to the memory region where netif->flags is?

Probably. I'm at it right now.

At which point does the netif go down here?
I don't know yet. ARP goes out OK and received fine. Then when it is time to
_SEND_ SYN/ACK netif seems to be down.

Reception _STILL WORKS_ , it properly receives the retransmitted SYN,
generates a proper SYN/ACK and tries to send it back but it fails again in
ip_route() because netif is presumably down.

That's strange, reception should only succeed if the netif is up (unless it's UDP DHCP traffic). For that, netif_is_up() is called in ip_input().

Yep. But it DOES work because it attempts to send a SYN/ACK on each of
SYN retransmits from the remote.

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