[icq-devel] Strange port numbers in file acks



Martin Öberg icqdevel at strickz.com
Mon Dec 30 19:58:18 CET 2002


I'm having some troubles sending files to ICQ 2002 & 2003. The
port numbers in the file acks that is returned are completely wrong. The
problem occurs both when the file ack is in a PEER_MSG_GREETING DC
packet and when it arrives through the server.

Below is an example of a PEER_MSG_GREETING file ack dump and some traces.
As you see the port is 65534/-2. Does this value have any known special
meaning?


[18:48:54 ICQP2P] DECRYPTED
00000000: D1 BA F1 CE-DA 07 0E 00-04 00 00 00-00 00 00 00  -¦±++...........
00000010: 00 00 00 00-00 00 1A 00-00 00 00 00-01 00 00 32  ...............2
00000020: 00 F0 2D 12-D9 30 91 D3-11 8D D7 00-10 4B 06 46  .=-.+0æ+.ì+..K.F
00000030: 2E 00 00 0D-00 00 00 46-69 6C 65 20-54 72 61 6E  .......File Tran
00000040: 73 66 65 72-00 00 01 01-00 00 00 00-00 00 00 00  sfer............
00000050: 00 00 00 25-00 00 00 08-00 00 00 74-65 73 74 66  .........testf
00000060: 69 6C 65 FE-FF FF FF 0B-00 70 61 73-73 32 2E 74  ile¦   ..pass2.t
00000070: 78 74 00 00-65 00 00 00-FF FE 00 00-             xt..e... ¦..
[18:48:54 ICQP2P] Direct: new direct package
[18:48:54 ICQP2P] Received PEER_MSG from 5195924
[18:48:54 ICQP2P] Handling PEER_MSG, command 2010, cookie 4, messagetype 26, status 0, flags 0
[18:48:54 ICQP2P] Handling PEER_MSG_GREETING, command 2010, cookie 4, messagetype 26, status 0, flags 0
[18:48:54 ICQP2P] PEER_MSG_GREETING, command: 50, type: File Transfer, typeID: 3
[18:48:54 ICQP2P] v8 File transfer ack thru direct connection from 5195924, port 65534, name 'pass2.txt', size 101, reason: ''



A formatted and commented version of the same dump:

D1 BA F1 CE // Checksum
DA 07       // Command, 2010 = ack
0E 00       // Unknown
04 00       // Sequence, 4
00 00 00 00 00 00 00 00 00 00 00 00 // Unknown
1A 00    // Type, 26
00 00    // Status
00 00    // Flags
01 00 00 // Message (empty)

32 00       // Subcommand, 50 = file request response
F0 2D 12-D9 30 91 D3-11 8D D7 00-10 4B 06 46 2E // Unknown
00 00       // Unknown
0D 00 00 00 46-69 6C 65 20-54 72 61 6E 73 66 65 72 // Type string, "File Transfer"
00 00 01 01-00 00 00 00-00 00 00 00 00 00 00 // Unknown
25 00 00 00 // Length, 37 bytes
08-00 00 00 74-65 73 74 66 69 6C 65 // Description, "testfile"
FE-FF       // Port, -2?
FF FF       // Unknown
0B-00 70 61 73-73 32 2E 74 78 74 // Filename, "pass2.txt"
00 00 65 00 // Filesize
00 00-FF FE // Port again?
00 00       // Unknown






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