Jak sprawdzić losowe resetowanie portu klienta TCP podłączonego za pomocą interfejsu sprzężenia zwrotnego do serwera

10

Mam pakiet testowy, który inicjuje serwer na hoście lokalnym, a następnie przeprowadza tysiące testów warunków skrajnych, które obejmują uruchamianie i zatrzymywanie klientów łączących się z tym serwerem lokalnym na tym samym komputerze. Próbuję znaleźć przyczynę wysłania RST przez klienta na serwer.

Oto sekwencja zdarzeń:

  1. klient inicjuje SYN
  2. Serwer odsyła SYN, ACK
  3. klient wysyła RST (zamiast ACK i nawiązywania połączenia)

Jedna obserwacja jest przy wielu okazjach, że serwery pracują w około 99 procentach procesora, chociaż wraca do normy w ciągu kilku sekund / minut.

Początkowo myślałem, że może tak być, ponieważ klient korzysta z portu z wcześniej zamkniętego połączenia, które jest w stanie TIME_WAIT, a więc kiedy serwer wysyła SYN, ACK na tym połączeniu klient wydaje RST. Chociaż byłem sceptyczny co do tego, dlaczego klient powinien używać portu w stanie TIME_WAIT, ale używam starego fedora core 4 i pomyślałem, że może nie ma właściwej implementacji TCP / IP :-).

Teraz nie wierzę, że to jest powód, ponieważ całe dostrojenie wokół naprawy powyższego problemu nie pomogło złagodzić problemu. Do Twojej wiadomości są zmiany, które wypróbowałem /etc/sysctl.conf:

net.ipv4.ip_local_port_range = 1024     65535
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_rfc1337 = 1
net.ipv4.tcp_tw_reuse = 1

Jeszcze jeden punkt, ten problem nie jest spójny. W rzeczywistości mogę odtworzyć ten problem dopiero po przejściu 15–35 cykli ponownego uruchamiania serwera i przeprowadzania wszystkich testów klienta.

Skończyły mi się wszystkie powody, dla których mogę wymyślić, dlaczego tak się dzieje, więc daj mi znać, jeśli ktoś ma jakieś pomysły na to, co może się dziać.

Szczegóły pakietu

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:45.378209 1032719 1858.494749 ::1                   ::1                   TCP      94     netview-aix-5 navisphere netview-aix-5 > navisphere [SYN] Seq=0 Win=32752 Len=0 MSS=16376 SACK_PERM=1 TSval=1587252 TSecr=0 WS=128

Frame 1032719: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:45.378209000 EDT
    Epoch Time: 1403722185.378209000 seconds
    [Time delta from previous captured frame: 0.005893000 seconds]
    [Time delta from previous displayed frame: 0.000000000 seconds]
    [Time since reference or first frame: 1858.494749000 seconds]
    Frame Number: 1032719
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 0, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Header length: 40 bytes
    Flags: 0x02 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32752
    [Calculated window size: 32752]
    Checksum: 0xf489 [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1587252, TSecr 0
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:45.378222 1032720 1858.494762 ::1                   ::1                   TCP      94     navisphere  netview-aix-5 navisphere > netview-aix-5 [SYN, ACK] Seq=0 Ack=1 Win=32728 Len=0 MSS=16376 SACK_PERM=1 TSval=1587252 TSecr=1587252 WS=128

Frame 1032720: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:45.378222000 EDT
    Epoch Time: 1403722185.378222000 seconds
    [Time delta from previous captured frame: 0.000013000 seconds]
    [Time delta from previous displayed frame: 0.000013000 seconds]
    [Time since reference or first frame: 1858.494762000 seconds]
    Frame Number: 1032720
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: navisphere (2162), Dst Port: netview-aix-5 (1665), Seq: 0, Ack: 1, Len: 0
    Source port: navisphere (2162)
    Destination port: netview-aix-5 (1665)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Acknowledgement number: 1    (relative ack number)
    Header length: 40 bytes
    Flags: 0x12 (SYN, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgement: Set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish acknowledge (SYN+ACK): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32728
    [Calculated window size: 32728]
    Checksum: 0xf7fa [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1587252, TSecr 1587252
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 1032719]
        [The RTT to ACK the segment was: 0.000013000 seconds]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:45.378228 1032721 1858.494768 ::1                   ::1                   TCP      74     netview-aix-5 navisphere netview-aix-5 > navisphere [RST] Seq=1 Win=0 Len=0

Frame 1032721: 74 bytes on wire (592 bits), 74 bytes captured (592 bits)
    Arrival Time: Jun 25, 2014 14:49:45.378228000 EDT
    Epoch Time: 1403722185.378228000 seconds
    [Time delta from previous captured frame: 0.000006000 seconds]
    [Time delta from previous displayed frame: 0.000006000 seconds]
    [Time since reference or first frame: 1858.494768000 seconds]
    Frame Number: 1032721
    Frame Length: 74 bytes (592 bits)
    Capture Length: 74 bytes (592 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP RST]
    [Coloring Rule String: tcp.flags.reset eq 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 20
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 1, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 1    (relative sequence number)
    Header length: 20 bytes
    Flags: 0x04 (RST)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .1.. = Reset: Set
            [Expert Info (Chat/Sequence): Connection reset (RST)]
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
    Window size value: 0
    [Calculated window size: 0]
    [Window size scaling factor: 128]
    Checksum: 0x4eea [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:48.375927 1032722 1861.492467 ::1                   ::1                   TCP      94     netview-aix-5 navisphere netview-aix-5 > navisphere [SYN] Seq=0 Win=32752 Len=0 MSS=16376 SACK_PERM=1 TSval=1588002 TSecr=0 WS=128

Frame 1032722: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:48.375927000 EDT
    Epoch Time: 1403722188.375927000 seconds
    [Time delta from previous captured frame: 2.997699000 seconds]
    [Time delta from previous displayed frame: 2.997699000 seconds]
    [Time since reference or first frame: 1861.492467000 seconds]
    Frame Number: 1032722
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 0, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Header length: 40 bytes
    Flags: 0x02 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32752
    [Calculated window size: 32752]
    Checksum: 0xf19b [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1588002, TSecr 0
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:48.375950 1032723 1861.492490 ::1                   ::1                   TCP      94     navisphere  netview-aix-5 [TCP Previous segment lost] navisphere > netview-aix-5 [SYN, ACK] Seq=2997725 Ack=1 Win=32728 Len=0 MSS=16376 SACK_PERM=1 TSval=1588002 TSecr=1588002 WS=128

Frame 1032723: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:48.375950000 EDT
    Epoch Time: 1403722188.375950000 seconds
    [Time delta from previous captured frame: 0.000023000 seconds]
    [Time delta from previous displayed frame: 0.000023000 seconds]
    [Time since reference or first frame: 1861.492490000 seconds]
    Frame Number: 1032723
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: Bad TCP]
    [Coloring Rule String: tcp.analysis.flags]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: navisphere (2162), Dst Port: netview-aix-5 (1665), Seq: 2997725, Ack: 1, Len: 0
    Source port: navisphere (2162)
    Destination port: netview-aix-5 (1665)
    [Stream index: 3374]
    Sequence number: 2997725    (relative sequence number)
    Acknowledgement number: 1    (relative ack number)
    Header length: 40 bytes
    Flags: 0x12 (SYN, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgement: Set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish acknowledge (SYN+ACK): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32728
    [Calculated window size: 32728]
    Checksum: 0x3414 [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1588002, TSecr 1588002
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 1032722]
        [The RTT to ACK the segment was: 0.000023000 seconds]
        [TCP Analysis Flags]
            [A segment before this frame was lost]
                [Expert Info (Warn/Sequence): Previous segment lost (common at capture start)]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:48.375958 1032724 1861.492498 ::1                   ::1                   TCP      74     netview-aix-5 navisphere netview-aix-5 > navisphere [RST] Seq=1 Win=0 Len=0

Frame 1032724: 74 bytes on wire (592 bits), 74 bytes captured (592 bits)
    Arrival Time: Jun 25, 2014 14:49:48.375958000 EDT
    Epoch Time: 1403722188.375958000 seconds
    [Time delta from previous captured frame: 0.000008000 seconds]
    [Time delta from previous displayed frame: 0.000008000 seconds]
    [Time since reference or first frame: 1861.492498000 seconds]
    Frame Number: 1032724
    Frame Length: 74 bytes (592 bits)
    Capture Length: 74 bytes (592 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP RST]
    [Coloring Rule String: tcp.flags.reset eq 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 20
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 1, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 1    (relative sequence number)
    Header length: 20 bytes
    Flags: 0x04 (RST)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .1.. = Reset: Set
            [Expert Info (Chat/Sequence): Connection reset (RST)]
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
    Window size value: 0
    [Calculated window size: 0]
    [Window size scaling factor: 128]
    Checksum: 0x4eea [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:54.376072 1032725 1867.492612 ::1                   ::1                   TCP      94     netview-aix-5 navisphere netview-aix-5 > navisphere [SYN] Seq=0 Win=32752 Len=0 MSS=16376 SACK_PERM=1 TSval=1589502 TSecr=0 WS=128

Frame 1032725: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:54.376072000 EDT
    Epoch Time: 1403722194.376072000 seconds
    [Time delta from previous captured frame: 6.000114000 seconds]
    [Time delta from previous displayed frame: 6.000114000 seconds]
    [Time since reference or first frame: 1867.492612000 seconds]
    Frame Number: 1032725
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 0, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Header length: 40 bytes
    Flags: 0x02 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32752
    [Calculated window size: 32752]
    Checksum: 0xebbf [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1589502, TSecr 0
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)

iptables-save wynik:

# Generated by iptables-save v1.3.0 on Thu Jun 26 10:15:33 2014
*filter
:FORWARD ACCEPT [0:0]
:INPUT ACCEPT [675:236200]
:OUTPUT ACCEPT [241:21540]
COMMIT
# Completed on Thu Jun 26 10:15:33 2014
fedora tcp tcpdump tcp-ip karoliński
źródło
Czy gniazdo klienta jest w trybie nieblokującym? Czy jest możliwe, że gniazdo klienta zostanie zamknięte do czasu zaakceptowania przez serwer? Czy masz czasy dla tych pakietów? Może pcap?
Stéphane Chazelas
1
Czy sprawdzasz wartość zwracaną connect()s? Czy to możliwe, że wykonujesz dwa nieblokujące connect()sna tym samym gnieździe? Czy jest możliwe, że niektórzy klienci zostaną zabici lub przerwani w jakiś sposób ( alarm()?) W środku connect()? Czy możesz go odtworzyć, gdy klient działa w trybie strace -fflub autrace?
Stéphane Chazelas
1
Coś fantazyjnego (nfqueue, limitowanie połączeń ...) w wynikach iptables-save? Możliwość osiągnięcia pewnego limitu zasobów? Ilu równoległych klientów? Czy to binddo konkretnego portu źródłowego?
Stéphane Chazelas
1
Lepiej byłoby dodać do pytania. Pytanie brzmi bardziej, czy te limity są osiągnięte (lub prawdopodobnie osiągnięte) w teście, niż to, jakie są w rzeczywistości.
Stéphane Chazelas
1
Domyślam się, że nacisk na stos ma jeden spadek połączenia po stronie klienta w stanie półotwartym. To połączenie zostaje zerwane (co oznacza, że ​​aplikacja kliencka powinna je postrzegać jako a ETIMEDOUT), a kiedy syn / ack jest w końcu przetwarzany przez stos, nie ma już więcej połączeń, z którymi można by je powiązać, a zatem zostaje zresetowany. Czy próbowałeś zwiększyć rozmiar synlogowania ( sysctl -w net.ipv4.tcp_max_syn_backlog=???)?
didierc

Odpowiedzi:

1

Chcę tylko zakończyć ten wątek przyjętym rozwiązaniem przy braku poprawki głównej przyczyny, którą, jak sądzę, jest implementacja stosu Fedory 4 TCP. Jako rozwiązanie wprowadziłem po prostu natychmiastową próbę ponownego połączenia na wypadek, gdyby przyczyną niepowodzenia był ETIMEDOUT, a zastosowany protokół to IPV6. To rozwiązało problem dla mnie i mojego zespołu na dobre z możliwym ryzykiem dodatkowego 3-minutowego opóźnienia w zgłaszaniu błędu w jakimkolwiek innym problemie z połączeniem powodującym ETIMEDOUT. To nie jest prawdziwe / idealne rozwiązanie problemu, ale zachęca nas do przejścia ... ponieważ ma to wpływ tylko na nasz automatyczny zestaw testów i nie jest wysyłany do klienta. Mam nadzieję, że w końcu ktoś, kto zna wystarczająco dobrze implementację stosu fedora 4 tcp / ip, rozwiąże tę tajemnicę na dobre.

karoliński
źródło