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Re: Handling TCP packets reordering
From: Max Dmitrichenko <dmitrmax () gmail com>
Date: Thu, 5 May 2011 01:13:13 +0400
2011/5/5 Jeff Morriss <jeff.morriss.ws () gmail com>:
Sake Blok wrote:On 4 mei 2011, at 22:11, Jeff Morriss wrote:I would think desegment_tcp() should be able to handle this by not calling your dissector for an out-of-order segment: it should be able to only call your dissector once it has a completely reassembled (desegmented) PDU. Looking through the code, it's not immediately obvious to me what the problem is.One case that can cause a problem is when the first segment of a PDU is received out-of-order. Or did your recent work also handle this exception, Jeff?Yep, that's the case rev 36304 fixed.
Sake and Jeff, thank you for your replies. Indeed the problem is when the first segment of multisegment PDU is received out-of-order, i.e. later than the second segment, for example. Provided that protocol is encrypted (including framing headers), I'm not able to deduct anything at the beginning of dissection. I try to decrypt this fragment, but decryption fails and more over the decryption context is spoiled after this try - all later packets are decrypted into the junk. If the first segment of PDU is received in order then all other segments seems to be assembled correctly despite of their order - I have observed such situations. Let's get back to your statement, Jeff. Suppose, we have PDU of 3 fragments which come in this order: 2, 1, 2 (dup), 3. What should I write in the dissector to handle this correctly? Or may be you can point me to the code of any existing dissector which handles this? -- Max ___________________________________________________________________________ Sent via: Wireshark-dev mailing list <wireshark-dev () wireshark org> Archives: http://www.wireshark.org/lists/wireshark-dev Unsubscribe: https://wireshark.org/mailman/options/wireshark-dev mailto:wireshark-dev-request () wireshark org?subject=unsubscribe
Current thread:
- Handling TCP packets reordering Max Dmitrichenko (May 04)
- Re: Handling TCP packets reordering Mikko Saarnivala (May 04)
- Re: Handling TCP packets reordering Jeff Morriss (May 04)
- Re: Handling TCP packets reordering Sake Blok (May 04)
- Re: Handling TCP packets reordering Jeff Morriss (May 04)
- Re: Handling TCP packets reordering Max Dmitrichenko (May 04)
- Re: Handling TCP packets reordering Sake Blok (May 04)
- Re: Handling TCP packets reordering Jeff Morriss (May 04)
- Re: Handling TCP packets reordering Sake Blok (May 04)
- Re: Handling TCP packets reordering Sake Blok (May 04)
- Re: Handling TCP packets reordering Jakub Zawadzki (May 07)
- Re: Handling TCP packets reordering Jeff Morriss (May 04)
- Re: Handling TCP packets reordering Max Dmitrichenko (May 04)