On Mon, Jun 04, 2007 at 08:39:21AM +0800, Wei Yongjun wrote:
Huh? The test new_mtu >= old_mtu should only hold if the sending router
is buggy which is what the hack is for.
Note here old_mtu is not the real old mtu, is the received message's size:
unsigned short old_mtu = ntohs(iph->tot_len);
So maybe the patch would like following.
The size of the packet that caused the ICMP is what we want here. That's
why the router must be buggy.
So I want to know how the route announce a MTU larger then 576, such as
1280? RFC says ICMP error message return as much as we can without
exceeding 576 bytes.
And ipv4 router alaways return as a packet size 576 because of this.
If MTU is greater then 576, HOST will used "mtu = guess_mtu(old_mtu)" to
get a MTU. Method of send ICMP Fragmentation Needed message is
difference from receive,
how can this resolve? Change the method of send ICMP Fragmentation
Needed message? I do not think so, the only think we can do is to
change the method of receive ICMP message.
Do you agree this?
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