lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 04 Jun 2007 12:03:57 +0800
From:	Wei Yongjun <yjwei@...fujitsu.com>
To:	Herbert Xu <herbert@...dor.apana.org.au>
CC:	netdev@...r.kernel.org
Subject: Re: [PATCH] Fix bug of update IPv4 PMTU when received ICMP Fragmentation
 Needed message


> 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?

-- 

A new email address of FJWAN is launched from Apr.1 2007.
The updated address is: yjwei@...fujitsu.com 
--------------------------------------------------
Wei Yongjun
Development Dept.I
Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
8/F., Civil Defense Building, No.189 Guangzhou Road,
Nanjing, 210029, China
TEL: +86+25-86630523-858
COINS: 79955-858
FAX: +86+25-83317685
MAIL: yjwei@...fujitsu.com
--------------------------------------------------

-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists