Re: Problem on SCTP

[Sun Paul]

Packet to SERVER (from router to SERVER)[ Source IP: 192.168.206.83,
Destination IP: 192.168.206.66. the IPv4 address parameter is
192.168.206.83 and 192.168.1.83 ]
================


No.     Time                          Source                SPort
Destination           Protocol DPort  Length Info
                                      DSCP
      2 2017-01-06 08:52:49.662321    192.168.206.83        50001
192.168.206.66        SCTP     3868   98     INIT
                                      CS0

Frame 2: 98 bytes on wire (784 bits), 98 bytes captured (784 bits)
    Encapsulation type: Ethernet (1)
    Arrival Time: Jan  6, 2017 16:52:49.662321000 Malay Peninsula Standard Time
    [Time shift for this packet: 0.000000000 seconds]
    Epoch Time: 1483692769.662321000 seconds
    [Time delta from previous captured frame: 0.000179000 seconds]
    [Time delta from previous displayed frame: 0.000179000 seconds]
    [Time since reference or first frame: 0.000179000 seconds]
    Frame Number: 2
    Frame Length: 98 bytes (784 bits)
    Capture Length: 98 bytes (784 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ethertype:ip:sctp]
Ethernet II, Src: Vmware_81:41:6b (00:50:56:81:41:6b), Dst:
Vmware_81:a6:a3 (00:50:56:81:a6:a3)
    Destination: Vmware_81:a6:a3 (00:50:56:81:a6:a3)
        Address: Vmware_81:a6:a3 (00:50:56:81:a6:a3)
        .... ..0. .... .... .... .... = LG bit: Globally unique
address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Source: Vmware_81:41:6b (00:50:56:81:41:6b)
        Address: Vmware_81:41:6b (00:50:56:81:41:6b)
        .... ..0. .... .... .... .... = LG bit: Globally unique
address (factory default)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
    Type: IPv4 (0x0800)
Internet Protocol Version 4, Src: 192.168.206.83, Dst: 192.168.206.66
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x02 (DSCP: CS0, ECN: ECT(0))
        0000 00.. = Differentiated Services Codepoint: Default (0)
        .... ..10 = Explicit Congestion Notification: ECN-Capable
Transport codepoint '10' (2)
    Total Length: 84
    Identification: 0x0000 (0)
    Flags: 0x02 (Don't Fragment)
        0... .... = Reserved bit: Not set
        .1.. .... = Don't fragment: Set
        ..0. .... = More fragments: Not set
    Fragment offset: 0
    Time to live: 63
    Protocol: SCTP (132)
    Header checksum: 0x1d3d [validation disabled]
        [Good: False]
        [Bad: False]
    Source: 192.168.206.83
    Destination: 192.168.206.66
    [Source GeoIP: Unknown]
    [Destination GeoIP: Unknown]
Stream Control Transmission Protocol, Src Port: 50001 (50001), Dst
Port: 3868 (3868)
    Source port: 50001
    Destination port: 3868
    Verification tag: 0x00000000
    [Assocation index: 0]
    Checksum: 0xa9a86d3f (not verified)

On Fri, Jan 13, 2017 at 11:27 AM, Sun Paul <paulrbk@xxxxxxxxx> wrote:
> Hi All
>
> below is the packet trace in text format.
>
>
> Packet received (From client to router)  [ Source IP: 192.168.206.83,
> Destination IP: 192.168.206.65. the IPv4 address parameter is
> 192.168.206.83 and 192.168.1.83 ]
> ======================
>
> No.     Time                          Source                SPort
> Destination           Protocol DPort  Length Info
>                                       DSCP
>       1 2017-01-06 08:52:49.662142    192.168.206.83        50001
> 192.168.206.65        SCTP     3868   98     INIT
>                                       CS0
>
> Frame 1: 98 bytes on wire (784 bits), 98 bytes captured (784 bits)
>     Encapsulation type: Ethernet (1)
>     Arrival Time: Jan  6, 2017 16:52:49.662142000 Malay Peninsula Standard Time
>     [Time shift for this packet: 0.000000000 seconds]
>     Epoch Time: 1483692769.662142000 seconds
>     [Time delta from previous captured frame: 0.000000000 seconds]
>     [Time delta from previous displayed frame: 0.000000000 seconds]
>     [Time since reference or first frame: 0.000000000 seconds]
>     Frame Number: 1
>     Frame Length: 98 bytes (784 bits)
>     Capture Length: 98 bytes (784 bits)
>     [Frame is marked: False]
>     [Frame is ignored: False]
>     [Protocols in frame: eth:ethertype:ip:sctp]
> Ethernet II, Src: RealtekU_54:81:87 (52:54:00:54:81:87), Dst:
> Vmware_81:41:6b (00:50:56:81:41:6b)
>     Destination: Vmware_81:41:6b (00:50:56:81:41:6b)
>         Address: Vmware_81:41:6b (00:50:56:81:41:6b)
>         .... ..0. .... .... .... .... = LG bit: Globally unique
> address (factory default)
>         .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
>     Source: RealtekU_54:81:87 (52:54:00:54:81:87)
>         Address: RealtekU_54:81:87 (52:54:00:54:81:87)
>         .... ..1. .... .... .... .... = LG bit: Locally administered
> address (this is NOT the factory default)
>         .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
>     Type: IPv4 (0x0800)
> Internet Protocol Version 4, Src: 192.168.206.83, Dst: 192.168.206.65
>     0100 .... = Version: 4
>     .... 0101 = Header Length: 20 bytes (5)
>     Differentiated Services Field: 0x02 (DSCP: CS0, ECN: ECT(0))
>         0000 00.. = Differentiated Services Codepoint: Default (0)
>         .... ..10 = Explicit Congestion Notification: ECN-Capable
> Transport codepoint '10' (2)
>     Total Length: 84
>     Identification: 0x0000 (0)
>     Flags: 0x02 (Don't Fragment)
>         0... .... = Reserved bit: Not set
>         .1.. .... = Don't fragment: Set
>         ..0. .... = More fragments: Not set
>     Fragment offset: 0
>     Time to live: 64
>     Protocol: SCTP (132)
>     Header checksum: 0x1c3e [validation disabled]
>         [Good: False]
>         [Bad: False]
>     Source: 192.168.206.83
>     Destination: 192.168.206.65
>     [Source GeoIP: Unknown]
>     [Destination GeoIP: Unknown]
> Stream Control Transmission Protocol, Src Port: 50001 (50001), Dst
> Port: 3868 (3868)
>     Source port: 50001
>     Destination port: 3868
>     Verification tag: 0x00000000
>     [Assocation index: 0]
>     Checksum: 0xbaea49e5 (not verified)
>     INIT chunk (Outbound streams: 3000, inbound streams: 3000)
>         Chunk type: INIT (1)
>             0... .... = Bit: Stop processing of the packet
>             .0.. .... = Bit: Do not report
>         Chunk flags: 0x00
>         Chunk length: 52
>         Initiate tag: 0xe79f40cb
>         Advertised receiver window credit (a_rwnd): 62464
>         Number of outbound streams: 3000
>         Number of inbound streams: 3000
>         Initial TSN: 176990880
>         IPv4 address parameter (Address: 192.168.206.83)
>             Parameter type: IPv4 address (0x0005)
>                 0... .... .... .... = Bit: Stop processing of chunk
>                 .0.. .... .... .... = Bit: Do not report
>             Parameter length: 8
>             IP Version 4 address: 192.168.206.83
>         IPv4 address parameter (Address: 192.168.1.83)
>             Parameter type: IPv4 address (0x0005)
>                 0... .... .... .... = Bit: Stop processing of chunk
>                 .0.. .... .... .... = Bit: Do not report
>             Parameter length: 8
>             IP Version 4 address: 192.168.1.83
>         Supported address types parameter (Supported types: IPv6, IPv4)
>             Parameter type: Supported address types (0x000c)
>                 0... .... .... .... = Bit: Stop processing of chunk
>                 .0.. .... .... .... = Bit: Do not report
>             Parameter length: 8
>             Supported address type: IPv6 address (6)
>             Supported address type: IPv4 address (5)
>         ECN parameter
>             Parameter type: ECN (0x8000)
>                 1... .... .... .... = Bit: Skip parameter and continue
> processing of the chunk
>                 .0.. .... .... .... = Bit: Do not report
>             Parameter length: 4
>         Forward TSN supported parameter
>             Parameter type: Forward TSN supported (0xc000)
>                 1... .... .... .... = Bit: Skip parameter and continue
> processing of the chunk
>                 .1.. .... .... .... = Bit: Do report
>             Parameter length: 4
>
> On Thu, Jan 12, 2017 at 6:53 PM, Michael Tuexen
> <Michael.Tuexen@xxxxxxxxxxxxxxxxx> wrote:
>>> On 12 Jan 2017, at 10:51, David Laight <David.Laight@xxxxxxxxxx> wrote:
>>>
>>> From: Sun Paul [mailto:paulrbk@xxxxxxxxx]
>>>> Sent: 12 January 2017 09:31
>>>> Let me clear the understanding. below is the flow.
>>>>
>>>> 1. Client sends to Linux Router: 192.168.206.83 -> 192.168.206.56,
>>>> 2. Linux router sends to SERVER where the source IP is unchanged:
>>>> 192.168.206.83 -> 192.168.206.66
>>>>
>>>> My question here is why SERVER cannot response this INIT chunk?
>>>
>>> Probably because the IP addresses embedded in the SCTP packet
>>> don't match the ones in the IP header.
>> I don't know if it matters on the linux implementation, but it shouldn't.
>> An SCTP endpoint should consider the source address of the packet containing
>> the INIT chunk and all the addresses listed in the INIT chunk as valid peer
>> addresses.
>>
>> Could we get a .pcap file of the packet containing the INIT chunk captured
>> at the server? I would expect an INIT-ACK or and ABORT. If that is not sent,
>> the checksum was wrong or some kind of packet filtering is active on the
>> server...
>>
>> Best regards
>> Michael
>>>
>>>       David
>>>
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>>