lwIP - A Lightweight TCP/IP stack - Bugs: bug #36318, Wrong UDP data size for small...
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bug #36318: Wrong UDP data size for small datagrams
Submitter: | dagos <dagos> | ||
Submitted: | Thu 26 Apr 2012 03:51:52 PM UTC | ||
Category: | UDP | Severity: | 3 - Normal |
Item Group: | Faulty Behaviour | Status: | Invalid |
Privacy: | Public | Assigned to: | goldsimon |
Open/Closed: | Closed | Planned Release: | None |
lwIP version: | 1.4.0 |
Fri 27 Apr 2012 12:34:23 PM UTC, comment #5: |
dagos <dagos> |
Thu 26 Apr 2012 06:49:49 PM UTC, comment #4: It works for me as well. Furthermore, my Udp.c (close to if not most current) has no assignment to p->tot_len anywhere in it. |
Bill Auerbach <billauerbach> |
Thu 26 Apr 2012 06:39:42 PM UTC, comment #3: Checksums are not optional for UDP either unless the sender sets the chksum field to zero.
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Simon Goldschmidt <goldsimon> |
Thu 26 Apr 2012 06:01:22 PM UTC, comment #2: I'm wondering if it were true for TCP, would TCP work at all? Checksums are not optional.
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Bill Auerbach <billauerbach> |
Thu 26 Apr 2012 04:04:26 PM UTC, comment #1: maybe same problem for TCP ? I don't yet try it... |
dagos <dagos> |
Thu 26 Apr 2012 03:51:52 PM UTC, original submission:
When a UDP datagram WITH PADDING is read by LWIP, p->tot_len includes padding size.
|
dagos <dagos> |
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Follow 3 latest changes.
Date | Changed by | Updated Field | Previous Value | => | Replaced by |
---|---|---|---|---|---|
2012-04-27 | goldsimon | Status | None | Invalid | |
Assigned to | None | goldsimon | |||
Open/Closed | Open | Closed |
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Corresponding source code
Padding is at Ethernet level, when ethernet frame is less than 64 bytes (including CRC)
I found the (real) problem.
It is not LWIP (sorry for this post...) but my input ethernet frame which was not correct (error in IP size field).
ethernet frame (at 0x11: 0x2e):
0000 00 30 84 89 9b 81 02 00 02 00 00 01 08 00 45 00 .0...... ......E.
0010 00 2e 1e 00 00 00 1e 11 69 a6 0a 81 00 0a 0a 81 ........ i.......
0020 00 0e 04 0e 04 fe 00 15 a0 5f 00 03 00 01 00 00 ........ ._......
0030 00 09 41 31 00 01 00 00 00 00 00 00 ..A1.... ....
instead of (at 0x11: 0x29):
0000 00 30 84 89 9b 81 02 00 02 00 00 01 08 00 45 00 .0...... ......E.
0010 00 29 1e 00 00 00 1e 11 69 a6 0a 81 00 0a 0a 81 ........ i.......
0020 00 0e 04 0e 04 fe 00 15 a0 5f 00 03 00 01 00 00 ........ ._......
0030 00 09 41 31 00 01 00 00 00 00 00 00 ..A1.... ....
So this bug can be close, sorry.