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Re: linux-ipsec: cornered: MTU and fragmentation bugs
- To: email@example.com (Richard Guy Briggs)
- Subject: Re: linux-ipsec: cornered: MTU and fragmentation bugs
- From: firstname.lastname@example.org (Alan Cox)
- Date: Thu, 25 Mar 1999 22:51:59 +0000 (GMT)
- Cc: email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org
- In-Reply-To: <199903252029.PAA20786@grendel.conscoop.ottawa.on.ca> from "Richard Guy Briggs" at Mar 25, 99 03:28:57 pm
- Sender: email@example.com
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> The place John Denker speaks of is in ip_fragment. If a packet is
> sent to ip_fragment() (such as at the end of ip_output()) without
> checking DF, then the packet gets dropped silently.
> > No patch ever seen.
> In case you didn't get it:
This doesnt appear to make sense.
> - --- 685,693 ----
> if (iph->frag_off & htons(IP_DF))
> NETDEBUG(printk("ip_queue_xmit: frag needed\n"));
> , dev); /* jsd */
This shouldnt be causing any problems because for all the cases that matter
its handled higher up
IGMP - never sets DF
ip_forward - checks DF
UDP - references it in 2.0 but doesnt use it
TCP - uses DF and sets the MTU below the point it will fragment
The only case I can see where it might be relevant and a bug is looping back
an oversized multicast frame when running as a multicast router.
Can someone tell me under what circumstances they observed the event