buglwIP - A Lightweight TCP/IP stack - Bugs: bug #19580, ICMP TTL is not decremented

 
 

You are not allowed to post comments on this tracker with your current authentication level.

bug #19580: ICMP TTL is not decremented

Submitter:  Jonathan Larmour <jifl>
Submitted:  Thu 12 Apr 2007 01:19:12 AM UTC
   
 
Category:  IPv4 Severity:  2 - Minor
Item Group:  Faulty Behaviour Status:  Fixed
Privacy:  Public Assigned to:  jifl
Open/Closed:  Closed Planned Release:  None
lwIP version:  None

Thu 12 Apr 2007 06:56:24 PM UTC, comment #3: 

I applied the patch.

Jonathan Larmour <jifl>
Group Member
Thu 12 Apr 2007 03:08:21 AM UTC, comment #2: 

Hmm, yes. After now researching this, I think the reporter got it the wrong way round. In fact we should send out an echo reply with the TTL reset back to default. I guess this is because the return route may be assymetric. The patch is much simpler now.


(file #12469)

Jonathan Larmour <jifl>
Group Member
Thu 12 Apr 2007 01:37:33 AM UTC, comment #1: 

I'm not sure that a host have to decrement ttl. I'm agree for a switch or router. I have experiment on my LAN, and when from my pc, I ping another host (pc/windows), TTL is the same in the ECHO & ECHO REPLY.  When I ping my router, the TTL is 128 in ECHO packet, and 64 in ECHO REPLY.

I don't have RFC here, do you have check what is the good behavior?

Frédéric Bernon <fbernon>
Group Member
Thu 12 Apr 2007 01:19:12 AM UTC, original submission:  

Someone noted on the lwip-users mailing list that the TTL on ICMP ECHO REPLIES is not decremented by 1 compared to the ECHO.

I'm pretty sure the attached patch solves this, but I'm not in a position to test it at the moment.

Jonathan Larmour <jifl>
Group Member

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attached Files
file #12469:  lwip.echo.ttl.2.patch.txt added by jifl (897B - text/plain)
file #12467:  lwip.echo.ttl.patch.txt added by jifl (1KiB - text/plain)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -email is unavailable- added by fbernon (Posted a comment)
  • -email is unavailable- added by jifl (Submitted the item)
  •  

    There are 0 votes so far. Votes easily highlight which items people would like to see resolved in priority, independently of the priority of the item set by tracker managers.

     

    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2007-04-12 jifl StatusIn Progress Fixed
        Open/ClosedOpen Closed
    2007-04-12 jifl Attached File- Added lwip.echo.ttl.2.patch.txt, #12469
    2007-04-12 jifl Attached File- Added lwip.echo.ttl.patch.txt, #12467

    Back to the top

    Powered by Savane 3.13-f8d8.
    Corresponding source code