lwIP - A Lightweight TCP/IP stack - Bugs: bug #31828, lwIP AUTOIP addresses accessed...
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bug #31828: lwIP AUTOIP addresses accessed from a host with a non-AUTOIP
Submitter: | Bill Auerbach <billauerbach> | ||
Submitted: | Wed 08 Dec 2010 08:53:03 PM UTC | ||
Category: | ARP | Severity: | 3 - Normal |
Item Group: | Faulty Behaviour | Status: | Invalid |
Privacy: | Public | Assigned to: | None |
Open/Closed: | Closed | Planned Release: | None |
lwIP version: | CVS Head |
Jump to the original submission
Wed 15 Dec 2010 06:04:21 PM UTC, comment #14: |
Bill Auerbach <billauerbach> |
Wed 15 Dec 2010 05:59:11 PM UTC, comment #13: Closing as invalid. |
Simon Goldschmidt <goldsimon> |
Wed 15 Dec 2010 05:53:00 PM UTC, comment #12: You can close this - I cannot get consistent behavior with other devices and/or with Windows when using static AutoIp (Link local) addresses. I guess there should be documentation somewhere that Link Local addresses are only valid when assigned using the method described in RFC 3927. Sorry for the noise. |
Bill Auerbach <billauerbach> |
Fri 10 Dec 2010 02:31:10 PM UTC, comment #11: If lwIP's behavior is correct then go ahead and close this. I thought it should work and can't find an documentation that says it doesn't have to. I have another widely distributed embedded device that does work with a static link-local address, but that could be that "it just works" but doesn't have to by RFC. |
Bill Auerbach <billauerbach> |
Thu 09 Dec 2010 11:41:44 PM UTC, comment #10: Oh, you meant another IP subnet while I thought you meant an address routed from another subnet to your device.
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Simon Goldschmidt <goldsimon> |
Thu 09 Dec 2010 06:36:34 PM UTC, comment #9: Based on the discussion in msg #4, this is the whole point. I asked the question in this other thread in the first place because windows would talk to 169.254 subnets - which as David pointed out is the main idea because the devices have self-configured link-local addresses.
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Bill Auerbach <billauerbach> |
Thu 09 Dec 2010 05:48:27 PM UTC, comment #8:
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Simon Goldschmidt <goldsimon> |
Thu 09 Dec 2010 04:17:00 PM UTC, comment #7: So I believe the problem is a packet from another subnet to an AutoIP address is not added to the ARP cache. So the ping reply doesn't get sent. I did not debug this further except to turn on LWIP_AUTOIP to see if code was being excluded that was needed for this to work. |
Bill Auerbach <billauerbach> |
Thu 09 Dec 2010 04:10:55 PM UTC, comment #6: I checked the code base I tested this with and it was there - your comment referring to the RFC tipped me off. Unless there were more than one patch and I have the original.
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Bill Auerbach <billauerbach> |
Thu 09 Dec 2010 03:51:12 PM UTC, comment #5: I think I already fixed that before savannah was hacked... Let me check that when I'm home again some time next week. I should find the time to backport changes from git then. |
Simon Goldschmidt <goldsimon> |
Thu 09 Dec 2010 03:47:16 PM UTC, comment #4: |
Bill Auerbach <billauerbach> |
Thu 09 Dec 2010 03:08:16 PM UTC, comment #3: It sounds like you expect AutoIP addresses to be treated as a special case with regards to routing. Do you have a reference for that? That the Linux box is sending the packets out suggests you're right (or that it's just sending them to the default interface). I don't know the AutoIP spec very well so it could be that the behaviour you describe is correct, but if we're going to fix it I'd like to understand it first! |
Kieran Mansley <kieranm> |
Thu 09 Dec 2010 02:46:33 PM UTC, comment #2: lwIP:
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Bill Auerbach <billauerbach> |
Thu 09 Dec 2010 02:36:34 PM UTC, comment #1: Can you give an example of the IP addresses and network masks configured at both ends? |
Kieran Mansley <kieranm> |
Wed 08 Dec 2010 08:53:03 PM UTC, original submission:
One cannot talk to an lwIP device with an AUTOIP address from a host that does not have an AUTOIP address.
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Bill Auerbach <billauerbach> |
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Follow 3 latest changes.
Date | Changed by | Updated Field | Previous Value | => | Replaced by |
---|---|---|---|---|---|
2010-12-15 | goldsimon | Status | None | Invalid | |
Open/Closed | Open | Closed | |||
2010-12-09 | dempson | Carbon-Copy | - | Added dempson |
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Corresponding source code
Ok, I found something to add:
RFC 3927:
1.6. Alternate Use Prohibition
Note that addresses in the 169.254/16 prefix SHOULD NOT be configured manually or by a DHCP server.
This will at least leave the breadcrumb for someone to know to not use a link-local static address.