Ethereal-users: [Ethereal-users] Q.931 SETUP with IP & TCP checksum error (win32) ?

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From: "Mads Nielsen (DXD)" <Mads.B.Nielsen@xxxxxxxxxxxxxxx>
Date: Thu, 10 Oct 2002 08:38:58 +0200
Hi,

This message was originally posted on the OpenH323 mailing list - but since the packets
are decoded with Ethereal (0.9.7 and previous versions) I might get some knowledge from
some of you...

I have just started using OpenH323 and noticed that "Ethereal" with "H.323 plugin"
not could reassemble a fragmented Q.931 SETUP frame (see attached log).
This applies to (at least) callgen323 and openphone.
The replies from the (remote) GK seems correct.

After some debugging in Ethereal I realized that it showed IP & TCP checksum errors
for these fragmented TPKT frames - and Ethereal refuses to desegment packets with such errors. 
I also noticed IP-checksum errors for "H.225 RAS" frames (but UDP checksum ok).
*** Why can't Ethereal hightlight errors in the summary view? It could have saved me some valuable time ;-)

Fortunately I just discovered that TCP-checksum validation can be turned off in Ethereal - and then
desegmentation seems to work...
But either Bill@xxxxxxxxxxx or OpenH323 seems to have a TCP-checksum problem ;-)

*** Does anybody have any comment on this?

I'm currently using the latest versions, i.e:
ethereal 0.9.7 (I recompiled the H.323 plugin - but also tried with prebuild configurations - e.g. 0.9.6)
openh323_20021008_win32.zip
pwlib_20021003_win32.zip
openphone_20021004_win32.zip
callgen323_20021006_win32.zip
Windows 2000 Workstation - SP2.

Thanks,
Mads Bligaard Nielsen
System Engineer, Core Software Development


Frame 55 (1514 bytes on wire, 1514 bytes captured)
    Arrival Time: Oct  8, 2002 17:55:59.831055000
    Time delta from previous packet: 0.270050000 seconds
    Time relative to first packet: 743.081878000 seconds
    Frame Number: 55
    Packet Length: 1514 bytes
    Capture Length: 1514 bytes
Ethernet II, Src: 00:b0:d0:8d:66:d5, Dst: 00:60:cf:20:c1:f9
    Destination: 00:60:cf:20:c1:f9 (00:60:cf:20:c1:f9)
    Source: 00:b0:d0:8d:66:d5 (00:b0:d0:8d:66:d5)
    Type: IP (0x0800)
Internet Protocol, Src Addr: 148.135.145.130 (148.135.145.130), Dst Addr: 172.30.250.147 (172.30.250.147)
    Version: 4
    Header length: 20 bytes
    Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
        0000 00.. = Differentiated Services Codepoint: Default (0x00)
        .... ..0. = ECN-Capable Transport (ECT): 0
        .... ...0 = ECN-CE: 0
    Total Length: 1500
    Identification: 0x71b3
    Flags: 0x04
        .1.. = Don't fragment: Set
        ..0. = More fragments: Not set
    Fragment offset: 0
    Time to live: 128
    Protocol: TCP (0x06)
    Header checksum: 0x0000 (incorrect, should be 0xb6ac)
    Source: 148.135.145.130 (148.135.145.130)
    Destination: 172.30.250.147 (172.30.250.147)
Transmission Control Protocol, Src Port: 3570 (3570), Dst Port: 1720 (1720), Seq: 992633435, Ack: 3325208158, Len: 1460
    Source port: 3570 (3570)
    Destination port: 1720 (1720)
    Sequence number: 992633435
    Next sequence number: 992634895
    Acknowledgement number: 3325208158
    Header length: 20 bytes
    Flags: 0x0010 (ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 0... = Push: Not set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 17520
    Checksum: 0xd28a (incorrect, should be 0x3789)
TPKT
    Version: 3
    Reserved: 0
    Length: 1977
Q.931
    Protocol discriminator: Q.931
    Call reference value length: 2
    Call reference value: 263A
    Message type: SETUP (0x05)
    Bearer capability
        Information element: Bearer capability
        Length: 3
        Coding standard: ITU-T standardized coding
        Information transfer capability: Unrestricted digital information
        Transfer mode: Circuit mode
        Information transfer rate: 384 kbit/s
        User information layer 1 protocol: Recommendation H.221 and H.242
    Display
        Information element: Display
        Length: 7
        Display information: dxdmap\000
    Calling party number
        Information element: Calling party number
        Length: 5
        Type of number: Unknown
        Numbering plan: E.164 ISDN/telephony numbering
        Number: 4001
    Called party number
        Information element: Called party number
        Length: 5
        Type of number: Unknown
        Numbering plan: E.164 ISDN/telephony numbering
        Number: 4009
    User-user
        Information element: User-user
        Length: 1937
        Protocol discriminator: X.208 and X.209 coded user information
[Short Frame: Q.931]

0000  00 60 cf 20 c1 f9 00 b0 d0 8d 66 d5 08 00 45 00   .`. ......f...E.
0010  05 dc 71 b3 40 00 80 06 00 00 94 87 91 82 ac 1e   ..q.@...........
0020  fa 93 0d f2 06 b8 3b 2a 62 5b c6 32 a6 5e 50 10   ......;*b[.2.^P.
0030  44 70 d2 8a 00 00 03 00 07 b9 08 02 26 3a 05 04   Dp..........&:..
0040  03 88 93 a5 28 07 64 78 64 6d 61 70 00 6c 05 81   ....(.dxdmap.l..
0050  34 30 30 31 70 05 81 34 30 30 39 7e 07 91 05 20   4001p..4009~... 
0060  b8 06 00 08 91 4a 00 04 02 40 05 00 64 00 78 00   .....J...@..d.x.
0070  64 00 6d 00 61 00 70 01 80 73 34 22 c0 09 00 00   d.m.a.p..s4"....
0080  3d 16 45 71 75 69 76 61 6c 65 6e 63 65 20 4f 70   =.Equivalence Op
0090  65 6e 50 68 6f 6e 65 00 00 18 31 2e 35 2e 34 20   enPhone...1.5.4 
00a0  28 4f 70 65 6e 48 33 32 33 20 76 31 2e 39 2e 39   (OpenH323 v1.9.9
00b0  29 00 00 00 01 01 80 73 3c 00 ac 1e fa 93 06 b8   )......s<.......
00c0  00 c8 87 a7 c8 7c eb 18 10 95 69 00 b0 d0 8d 66   .....|....i....f
00d0  d5 00 c5 1d 80 04 07 00 94 87 91 82 0d f2 11 00   ................
00e0  c8 87 a7 c8 7c eb 18 10 95 6a 00 b0 d0 8d 66 d5   ....|....j....f.
00f0  84 f3 1a 4c 40 00 00 06 04 01 00 4c 10 b5 00 53   ...L@......L...S
0100  4c 2a 02 00 00 00 00 00 f9 01 00 00 f9 01 01 00   L*..............
0110  04 00 00 00 00 00 11 00 01 00 40 1f 00 00 d7 0f   ..........@.....
0120  00 00 00 01 04 00 02 00 f9 01 00 00 80 12 1c 40   ...............@
0130  01 00 94 87 91 82 13 8c 00 94 87 91 82 13 8d 08   ................
0140  41 00 00 64 0c 10 b5 00 53 4c 2a 02 00 00 00 00   A..d....SL*.....
0150  00 f9 01 00 00 f9 01 01 00 04 00 00 00 00 00 11   ................
0160  00 01 00 40 1f 00 00 d7 0f 00 00 00 01 04 00 02   ...@............
0170  00 f9 01 00 00 80 0b 0d 40 01 00 94 87 91 82 13   ........@.......
0180  8d 84 4c 40 00 00 06 04 01 00 4c 10 b5 00 53 4c   ..L@xxxxxxxxxxxx
0190  2a 02 00 00 00 00 00 40 01 00 00 40 01 02 00 08   *......@...@....
01a0  00 00 00 00 00 31 00 01 00 40 1f 00 00 59 06 00   .....1...@...Y..
01b0  00 41 00 00 00 02 00 40 01 00 00 80 12 1c 40 01   .A.....@......@.
01c0  00 94 87 91 82 13 8c 00 94 87 91 82 13 8d 00 41   ...............A
01d0  00 00 65 0c 10 b5 00 53 4c 2a 02 00 00 00 00 00   ..e....SL*......
01e0  40 01 00 00 40 01 02 00 08 00 00 00 00 00 31 00   @...@.........1.
01f0  01 00 40 1f 00 00 59 06 00 00 41 00 00 00 02 00   ..@...Y...A.....
0200  40 01 00 00 80 0b 0d 40 01 00 94 87 91 82 13 8d   @......@........
0210  80 27 40 00 00 06 04 01 00 4c 10 09 00 00 3d 06   .'@......L....=.
0220  4c 50 43 2d 31 30 80 11 1c 00 01 00 94 87 91 82   LPC-10..........
0230  13 8c 00 94 87 91 82 13 8d 1d 00 00 66 0c 10 09   ............f...
0240  00 00 3d 06 4c 50 43 2d 31 30 80 0b 0d 00 01 00   ..=.LPC-10......
0250  94 87 91 82 13 8d 80 20 40 00 00 06 04 01 00 4e   ....... @......N
0260  0c 03 00 83 00 80 11 1c 00 01 00 94 87 91 82 13   ................
0270  8c 00 94 87 91 82 13 8d 16 00 00 67 0e 0c 03 00   ...........g....
0280  83 00 80 0b 0d 00 01 00 94 87 91 82 13 8d 80 1d   ................
0290  40 00 00 06 04 01 00 4d 60 05 80 11 1c 00 01 00   @......M`.......
02a0  94 87 91 82 13 8c 00 94 87 91 82 13 8d 13 00 00   ................
02b0  68 0d 60 05 80 0b 0d 00 01 00 94 87 91 82 13 8d   h.`.............
02c0  80 1d 40 00 00 06 04 01 00 4d 40 05 80 11 1c 00   ..@......M@.....
02d0  01 00 94 87 91 82 13 8c 00 94 87 91 82 13 8d 13   ................
02e0  00 00 69 0d 40 05 80 0b 0d 00 01 00 94 87 91 82   ..i.@...........
02f0  13 8d 80 4d 40 00 00 06 04 01 00 4c 10 09 00 00   ...M@......L....
0300  3d 2c 47 2e 37 32 36 2d 31 36 6b 00 0a 20 11 2d   =,G.726-16k.. .-
0310  30 a0 a1 2a 30 f0 a1 2a 30 50 a2 2a 30 2a f7 07   0..*0..*0P.*0*..
0320  30 20 a4 2a 30 24 f7 07 30 1e f7 07 30 a4 80 11   0 .*0$..0...0...
0330  1c 00 01 00 94 87 91 82 13 8c 00 94 87 91 82 13   ................
0340  8d 43 00 00 6a 0c 10 09 00 00 3d 2c 47 2e 37 32   .C..j.....=,G.72
0350  36 2d 31 36 6b 00 0a 20 11 2d 30 a0 a1 2a 30 f0   6-16k.. .-0..*0.
0360  a1 2a 30 50 a2 2a 30 2a f7 07 30 20 a4 2a 30 24   .*0P.*0*..0 .*0$
0370  f7 07 30 1e f7 07 30 a4 80 0b 0d 00 01 00 94 87   ..0...0.........
0380  91 82 13 8d 80 4d 40 00 00 06 04 01 00 4c 10 09   .....M@......L..
0390  00 00 3d 2c 47 2e 37 32 36 2d 32 34 6b 00 0a 47   ..=,G.726-24k..G
03a0  2e 37 32 36 2d 31 36 6b 00 00 20 11 2d 30 a0 a1   .726-16k.. .-0..
03b0  2a 30 f0 a1 2a 30 50 a2 2a 30 2a f7 07 30 20 a4   *0..*0P.*0*..0 .
03c0  80 11 1c 00 01 00 94 87 91 82 13 8c 00 94 87 91   ................
03d0  82 13 8d 43 00 00 6b 0c 10 09 00 00 3d 2c 47 2e   ...C..k.....=,G.
03e0  37 32 36 2d 32 34 6b 00 0a 47 2e 37 32 36 2d 31   726-24k..G.726-1
03f0  36 6b 00 00 20 11 2d 30 a0 a1 2a 30 f0 a1 2a 30   6k.. .-0..*0..*0
0400  50 a2 2a 30 2a f7 07 30 20 a4 80 0b 0d 00 01 00   P.*0*..0 .......
0410  94 87 91 82 13 8d 80 4d 40 00 00 06 04 01 00 4c   .......M@......L
0420  10 09 00 00 3d 2c 47 2e 37 32 36 2d 33 32 6b 00   ....=,G.726-32k.
0430  0a 47 2e 37 32 36 2d 32 34 6b 00 00 47 2e 37 32   .G.726-24k..G.72
0440  36 2d 31 36 6b 00 00 20 11 2d 30 a0 a1 2a 30 f0   6-16k.. .-0..*0.
0450  a1 2a 80 11 1c 00 01 00 94 87 91 82 13 8c 00 94   .*..............
0460  87 91 82 13 8d 43 00 00 6c 0c 10 09 00 00 3d 2c   .....C..l.....=,
0470  47 2e 37 32 36 2d 33 32 6b 00 0a 47 2e 37 32 36   G.726-32k..G.726
0480  2d 32 34 6b 00 00 47 2e 37 32 36 2d 31 36 6b 00   -24k..G.726-16k.
0490  00 20 11 2d 30 a0 a1 2a 30 f0 a1 2a 80 0b 0d 00   . .-0..*0..*....
04a0  01 00 94 87 91 82 13 8d 80 4d 40 00 00 06 04 01   .........M@.....
04b0  00 4c 10 09 00 00 3d 2c 47 2e 37 32 36 2d 34 30   .L....=,G.726-40
04c0  6b 00 0a 47 2e 37 32 36 2d 33 32 6b 00 00 47 2e   k..G.726-32k..G.
04d0  37 32 36 2d 32 34 6b 00 00 47 2e 37 32 36 2d 31   726-24k..G.726-1
04e0  36 6b 00 00 80 11 1c 00 01 00 94 87 91 82 13 8c   6k..............
04f0  00 94 87 91 82 13 8d 43 00 00 6d 0c 10 09 00 00   .......C..m.....
0500  3d 2c 47 2e 37 32 36 2d 34 30 6b 00 0a 47 2e 37   =,G.726-40k..G.7
0510  32 36 2d 33 32 6b 00 00 47 2e 37 32 36 2d 32 34   26-32k..G.726-24
0520  6b 00 00 47 2e 37 32 36 2d 31 36 6b 00 00 80 0b   k..G.726-16k....
0530  0d 00 01 00 94 87 91 82 13 8d 80 1d 40 00 00 06   ............@...
0540  04 01 00 4c 60 1d 80 11 1c 00 01 00 94 87 91 82   ...L`...........
0550  13 8c 00 94 87 91 82 13 8d 13 00 00 6e 0c 60 1d   ............n.`.
0560  80 0b 0d 00 01 00 94 87 91 82 13 8d 80 1d 40 00   ..............@.
0570  00 06 04 01 00 4c 20 1d 80 11 1c 00 01 00 94 87   .....L .........
0580  91 82 13 8c 00 94 87 91 82 13 8d 13 00 00 6f 0c   ..............o.
0590  20 1d 80 0b 0d 00 01 00 94 87 91 82 13 8d 80 22    .............."
05a0  40 00 00 06 04 01 00 48 71 03 51 00 80 01 00 80   @......Hq.Q.....
05b0  11 1c 00 02 00 94 87 91 82 13 8e 00 94 87 91 82   ................
05c0  13 8f 22 40 00 00 06 04 01 00 48 6b 03 51 00 80   .."@......Hk.Q..
05d0  01 00 80 11 1c 00 02 00 94 87 91 82 13 8e 00 94   ................
05e0  87 91 82 13 8f 01 00 01 00 01                     ..........

Frame 56 (571 bytes on wire, 571 bytes captured)
    Arrival Time: Oct  8, 2002 17:55:59.831090000
    Time delta from previous packet: 0.000035000 seconds
    Time relative to first packet: 743.081913000 seconds
    Frame Number: 56
    Packet Length: 571 bytes
    Capture Length: 571 bytes
Ethernet II, Src: 00:b0:d0:8d:66:d5, Dst: 00:60:cf:20:c1:f9
    Destination: 00:60:cf:20:c1:f9 (00:60:cf:20:c1:f9)
    Source: 00:b0:d0:8d:66:d5 (00:b0:d0:8d:66:d5)
    Type: IP (0x0800)
Internet Protocol, Src Addr: 148.135.145.130 (148.135.145.130), Dst Addr: 172.30.250.147 (172.30.250.147)
    Version: 4
    Header length: 20 bytes
    Differentiated Services Field: 0x00 (DSCP 0x00: Default; ECN: 0x00)
        0000 00.. = Differentiated Services Codepoint: Default (0x00)
        .... ..0. = ECN-Capable Transport (ECT): 0
        .... ...0 = ECN-CE: 0
    Total Length: 557
    Identification: 0x71b4
    Flags: 0x04
        .1.. = Don't fragment: Set
        ..0. = More fragments: Not set
    Fragment offset: 0
    Time to live: 128
    Protocol: TCP (0x06)
    Header checksum: 0x0000 (incorrect, should be 0xba5a)
    Source: 148.135.145.130 (148.135.145.130)
    Destination: 172.30.250.147 (172.30.250.147)
Transmission Control Protocol, Src Port: 3570 (3570), Dst Port: 1720 (1720), Seq: 992634895, Ack: 3325208158, Len: 517
    Source port: 3570 (3570)
    Destination port: 1720 (1720)
    Sequence number: 992634895
    Next sequence number: 992635412
    Acknowledgement number: 3325208158
    Header length: 20 bytes
    Flags: 0x0018 (PSH, ACK)
        0... .... = Congestion Window Reduced (CWR): Not set
        .0.. .... = ECN-Echo: Not set
        ..0. .... = Urgent: Not set
        ...1 .... = Acknowledgment: Set
        .... 1... = Push: Set
        .... .0.. = Reset: Not set
        .... ..0. = Syn: Not set
        .... ...0 = Fin: Not set
    Window size: 17520
    Checksum: 0xcedb (incorrect, should be 0x1e2c)
Data (517 bytes)

0000  00 60 cf 20 c1 f9 00 b0 d0 8d 66 d5 08 00 45 00   .`. ......f...E.
0010  02 2d 71 b4 40 00 80 06 00 00 94 87 91 82 ac 1e   .-q.@...........
0020  fa 93 0d f2 06 b8 3b 2a 68 0f c6 32 a6 5e 50 18   ......;*h..2.^P.
0030  44 70 ce db 00 00 00 01 00 81 fc 02 81 f1 02 70   Dp.............p
0040  01 06 00 08 81 75 00 07 80 13 80 00 32 00 01 00   .....u......2...
0050  00 01 00 00 01 00 00 0c c0 01 00 01 80 11 80 00   ................
0060  00 20 20 b5 00 53 4c 2a 02 00 00 00 00 00 f9 01   .  ..SL*........
0070  00 00 f9 01 01 00 04 00 00 00 00 00 11 00 01 00   ................
0080  40 1f 00 00 d7 0f 00 00 00 01 04 00 02 00 f9 01   @...............
0090  00 00 80 00 01 20 20 b5 00 53 4c 2a 02 00 00 00   .....  ..SL*....
00a0  00 00 40 01 00 00 40 01 02 00 08 00 00 00 00 00   ..@...@.........
00b0  31 00 01 00 40 1f 00 00 59 06 00 00 41 00 00 00   1...@...Y...A...
00c0  02 00 40 01 00 00 80 00 02 20 20 09 00 00 3d 06   ..@......  ...=.
00d0  4c 50 43 2d 31 30 80 00 03 24 18 03 00 e6 00 80   LPC-10...$......
00e0  00 04 22 c0 17 80 00 05 22 80 17 80 00 06 20 20   ..".....".....  
00f0  09 00 00 3d 2c 47 2e 37 32 36 2d 31 36 6b 00 f0   ...=,G.726-16k..
0100  20 11 2d 30 a0 a1 2a 30 f0 a1 2a 30 50 a2 2a 30    .-0..*0..*0P.*0
0110  2a f7 07 30 20 a4 2a 30 24 f7 07 30 1e f7 07 30   *..0 .*0$..0...0
0120  a4 80 00 07 20 20 09 00 00 3d 2c 47 2e 37 32 36   ....  ...=,G.726
0130  2d 32 34 6b 00 f0 47 2e 37 32 36 2d 31 36 6b 00   -24k..G.726-16k.
0140  00 20 11 2d 30 a0 a1 2a 30 f0 a1 2a 30 50 a2 2a   . .-0..*0..*0P.*
0150  30 2a f7 07 30 20 a4 80 00 08 20 20 09 00 00 3d   0*..0 ....  ...=
0160  2c 47 2e 37 32 36 2d 33 32 6b 00 f0 47 2e 37 32   ,G.726-32k..G.72
0170  36 2d 32 34 6b 00 00 47 2e 37 32 36 2d 31 36 6b   6-24k..G.726-16k
0180  00 00 20 11 2d 30 a0 a1 2a 30 f0 a1 2a 80 00 09   .. .-0..*0..*...
0190  20 20 09 00 00 3d 2c 47 2e 37 32 36 2d 34 30 6b     ...=,G.726-40k
01a0  00 f0 47 2e 37 32 36 2d 33 32 6b 00 00 47 2e 37   ..G.726-32k..G.7
01b0  32 36 2d 32 34 6b 00 00 47 2e 37 32 36 2d 31 36   26-24k..G.726-16
01c0  6b 00 00 80 00 0a 20 c0 ef 80 00 0b 20 40 ef 80   k..... ..... @..
01d0  00 0c 08 e2 03 51 00 80 01 00 80 00 0d 08 d6 03   .....Q..........
01e0  51 00 80 01 00 80 00 0e 83 01 50 80 00 0f 83 01   Q.........P.....
01f0  10 80 00 10 83 01 40 80 00 11 8a 06 14 04 30 2d   ......@.......0-
0200  31 36 00 80 01 04 0b 00 00 00 01 00 02 00 03 00   16..............
0210  04 00 05 00 06 00 07 00 08 00 09 00 0a 00 0b 00   ................
0220  00 0c 00 00 0d 00 00 0e 02 00 0f 00 10 00 11 07   ................
0230  01 00 32 80 c0 d5 48 04 80 01 80                  ..2...H....