ip_queue_xmit2 inconsistency regarding skb->sk

From: Rolf Fokkens (fokkensr@linux06.vertis.nl)
Date: Wed Nov 28 2001 - 06:26:51 EST


Hi!

I posted a kernel oops related to netfilter/REDIRECT. It seems like
ip_queue_xmit2 crashes on (skb->sk == NULL) in calling

    ip_dont_fragment(sk, &rt->u.dst)

which can't handle the (sk == NULL) situation. Of course there is the matter of
why (sk == NULL) in the first place. Haven't figured that out yet, nf_hook_slow
may cause do this somehow.

The other matter however is wether or not ip_queue_xmit2 should be able to
handle the (skb->sk == NULL) situation. The code is not consistent on that
subject.

It seems like the if statement:

    if (skb_headroom(skb) < dev->hard_header_len && dev->hard_header) {

handles the (sk == NULL) situation, given the line "if (sk)". Other parts of
ip_queue_xmit2 seem to assume (sk != NULL), like the ip_dont_fragment call
or lines like "skb->priority = sk->priority".

OK, this is not the answer on the why of the kernel oops. I hope however that
this question is related and helps in finding the answer

Rolf
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This archive was generated by hypermail 2b29 : Fri Nov 30 2001 - 21:00:30 EST