* Re: [Lksctp-developers] sctp and select
@ 2008-04-29 2:03 Vlad Yasevich
0 siblings, 0 replies; only message in thread
From: Vlad Yasevich @ 2008-04-29 2:03 UTC (permalink / raw)
To: linux-sctp
muskala magda wrote:
> hi,
>
> i am trying to rn this server. the (low level)
> communication seems to be done. but after accepting
> the connection, the select doesn't notice an incoming
> data. it notices only the 4 way handshake & closing
> packets, but not the data. the program waits in this
> line:
>
> if (select(fdmax+1, &read_fds, NULL, NULL, NULL)) {
>
> there is also an error after cookie echo received by
> the server, but as already mentioned, the
> communication seems not to be broken. are the data
> buffered? how can i check it/read it? how can i (if it
> is possible at all) "force" the select to notice the
> incoming data packets?
It looks like the system you are talking to is utterly
broken.
> No. Time Source Destination
> Protocol Info
> 484981 192374.502964 192.168.1.233
> 192.168.1.109 SCTP DATA
>
> Frame 484981 (72 bytes on wire, 72 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.233 (192.168.1.233),
> Dst: 192.168.1.109 (192.168.1.109)
> Stream Control Transmission Protocol, Src Port: 3072
> (3072), Dst Port: 10000 (10000)
> Source port: 3072
> Destination port: 10000
> Verification tag: 0x4d855e4f
> Checksum: 0x5edddafd [correct CRC32C]
> DATA chunk(ordered, complete segment, TSN:
> 3998009280, SID: 0, SSN: 1, PPID: 0, payload length: 8
> bytes)
> Chunk type: DATA (0)
> Chunk flags: 0x03
> Chunk length: 24
> TSN: 3998009280
> Stream Identifier: 0x0000
> Stream sequence number: 1
First of all, the very first data chunk of an association has
to start with a SSN of 0.
> Payload protocol identifier: not specified (0)
> Data (8 bytes)
>
> 0000 72 63 23 23 23 32 36 39
> rc###269
> Data: 7263232323323639
>
>
> No. Time Source Destination
> Protocol Info
> 484999 192380.098573 192.168.1.233
> 192.168.1.109 SCTP DATA
>
> Frame 484999 (320 bytes on wire, 320 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.233 (192.168.1.233),
> Dst: 192.168.1.109 (192.168.1.109)
> Stream Control Transmission Protocol, Src Port: 3072
> (3072), Dst Port: 10000 (10000)
> Source port: 3072
> Destination port: 10000
> Verification tag: 0x4d855e4f
> Checksum: 0x9b833a01 [correct CRC32C]
> DATA chunk(ordered, complete segment, TSN:
> 3998009281, SID: 0, SSN: 1, PPID: 0, payload length:
> 256 bytes)
> Chunk type: DATA (0)
> Chunk flags: 0x03
> Chunk length: 272
> TSN: 3998009281
> Stream Identifier: 0x0000
> Stream sequence number: 1
> Payload protocol identifier: not specified (0)
> Data (256 bytes)
>
> 0000 68 6f 73 74 6e 61 6d 65 20 45 44 4f 53 4b 32 36
> hostname EDOSK26
> 0010 37 34 0a 2f 62 69 6e 2f 65 78 70 61 6e 64 20 2f
> 74./bin/expand /
> 0020 65 74 63 2f 72 61 6d 66 73 2e 69 6d 67 20 2f 64
> etc/ramfs.img /d
> 0030 65 76 2f 72 61 6d 30 0a 2f 62 69 6e 2f 65 78 70
> ev/ram0./bin/exp
> 0040 61 6e 64 20 2f 65 74 63 2f 72 61 6d 66 73 2e 69
> and /etc/ramfs.i
> 0050 6d 67 20 2f 64 65 76 2f 72 61 6d 31 0a 6d 6f 75
> mg /dev/ram1.mou
> 0060 6e 74 20 2d 74 20 70 72 6f 63 20 70 72 6f 63 20
> nt -t proc proc
> 0070 2f 70 72 6f 63 0a 6d 6f 75 6e 74 20 2d 74 20 65
> /proc.mount -t e
> 0080 78 74 32 20 2f 64 65 76 2f 72 61 6d 30 20 2f 76
> xt2 /dev/ram0 /v
> 0090 61 72 0a 6d 6f 75 6e 74 20 2d 74 20 65 78 74 32
> ar.mount -t ext2
> 00a0 20 2f 64 65 76 2f 72 61 6d 31 20 2f 65 74 63 2f
> /dev/ram1 /etc/
> 00b0 63 6f 6e 66 69 67 0a 6d 6b 64 69 72 20 2f 76 61
> config.mkdir /va
> 00c0 72 2f 74 6d 70 0a 6d 6b 64 69 72 20 2f 76 61 72
> r/tmp.mkdir /var
> 00d0 2f 6c 6f 67 0a 6d 6b 64 69 72 20 2f 76 61 72 2f
> /log.mkdir /var/
> 00e0 72 75 6e 0a 6d 6b 64 69 72 20 2f 76 61 72 2f 6c
> run.mkdir /var/l
> 00f0 6f 63 6b 0a 66 6c 61 74 66 73 64 20 2d 72 0a 63
> ock.flatfsd -r.c
> Data:
> 686F73746E616D652045444F534B323637340A2F62696E2F...
>
>
> No. Time Source Destination
> Protocol Info
> 485007 192385.449421 192.168.1.233
> 192.168.1.109 SCTP DATA
>
> Frame 485007 (80 bytes on wire, 80 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.233 (192.168.1.233),
> Dst: 192.168.1.109 (192.168.1.109)
> Stream Control Transmission Protocol, Src Port: 3072
> (3072), Dst Port: 10000 (10000)
> Source port: 3072
> Destination port: 10000
> Verification tag: 0x4d855e4f
> Checksum: 0xa6294f39 [correct CRC32C]
> DATA chunk(ordered, complete segment, TSN:
> 3998009282, SID: 0, SSN: 1, PPID: 0, payload length:
> 13 bytes)
> Chunk type: DATA (0)
> Chunk flags: 0x03
> Chunk length: 29
> TSN: 3998009282
> Stream Identifier: 0x0000
> Stream sequence number: 1
Secondly, each subsequent complete DATA chunk must increment the Stream
sequence number. SSN 1 has already been received above.
The only time that SSN remains the same is when fragment DATA chunks
are sent.
Looks like the sender SCTP stack has a bug with ordered DATA chunks.
-vlad
> Payload protocol identifier: not specified (0)
> Chunk padding: 303030
> Data (13 bytes)
>
> 0000 61 74 20 2f 65 74 63 2f 6d 6f 74 64 0a
> at /etc/motd.
> Data: 6174202F6574632F6D6F74640A
>
> No. Time Source Destination
> Protocol Info
> 485008 192385.647279 192.168.1.109
> 192.168.1.233 SCTP SACK
>
> Frame 485008 (64 bytes on wire, 64 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.109 (192.168.1.109),
> Dst: 192.168.1.233 (192.168.1.233)
> Stream Control Transmission Protocol, Src Port: 10000
> (10000), Dst Port: 3072 (3072)
> Source port: 10000
> Destination port: 3072
> Verification tag: 0xee4cc7c0
> Checksum: 0xd87dd0d3 [correct CRC32C]
> SACK chunk (Cumulative TSN: 3998009282, a_rwnd:
> 55019, gaps: 0, duplicate TSNs: 0)
> Chunk type: SACK (3)
> Chunk flags: 0x00
> Chunk length: 16
> Cumulative TSN ACK: 3998009282
> Advertised receiver window credit (a_rwnd):
> 55019
> Number of gap acknowledgement blocks: 0
> Number of duplicated TSNs: 0
>
> No. Time Source Destination
> Protocol Info
> 485203 192463.052409 192.168.1.233
> 192.168.1.109 SCTP SHUTDOWN
>
> Frame 485203 (62 bytes on wire, 62 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.233 (192.168.1.233),
> Dst: 192.168.1.109 (192.168.1.109)
> Stream Control Transmission Protocol, Src Port: 3072
> (3072), Dst Port: 10000 (10000)
> Source port: 3072
> Destination port: 10000
> Verification tag: 0x4d855e4f
> Checksum: 0xfa0aa00c [correct CRC32C]
> SHUTDOWN chunk (Cumulative TSN ack: 1795865471)
> Chunk type: SHUTDOWN (7)
> Chunk flags: 0x00
> Chunk length: 8
> Cumulative TSN Ack: 1795865471
>
> No. Time Source Destination
> Protocol Info
> 485204 192463.052528 192.168.1.109
> 192.168.1.233 SCTP SHUTDOWN_ACK
>
> Frame 485204 (52 bytes on wire, 52 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.109 (192.168.1.109),
> Dst: 192.168.1.233 (192.168.1.233)
> Stream Control Transmission Protocol, Src Port: 10000
> (10000), Dst Port: 3072 (3072)
> Source port: 10000
> Destination port: 3072
> Verification tag: 0xee4cc7c0
> Checksum: 0x6df73964 [correct CRC32C]
> SHUTDOWN_ACK chunk
> Chunk type: SHUTDOWN_ACK (8)
> Chunk flags: 0x00
> Chunk length: 4
>
> No. Time Source Destination
> Protocol Info
> 485205 192463.145419 192.168.1.233
> 192.168.1.109 SCTP SHUTDOWN_COMPLETE
>
> Frame 485205 (62 bytes on wire, 62 bytes captured)
> Linux cooked capture
> Internet Protocol, Src: 192.168.1.233 (192.168.1.233),
> Dst: 192.168.1.109 (192.168.1.109)
> Stream Control Transmission Protocol, Src Port: 3072
> (3072), Dst Port: 10000 (10000)
> Source port: 3072
> Destination port: 10000
> Verification tag: 0x4d855e4f
> Checksum: 0x9b456826 [correct CRC32C]
> SHUTDOWN_COMPLETE chunk
> Chunk type: SHUTDOWN_COMPLETE (14)
> Chunk flags: 0x00
> Chunk length: 4
>
>
> --
>
> With your feet on the air and your head on the ground
> Try this trick and spin it, yeah
> Your head will collapse if there's nothing in it
> And you'll ask yourself
>
> Where is my mind?
> Where is my mind?
> Where is my mind?
>
>
> __________________________________________________________
> Gesendet von Yahoo! Mail.
> Mehr Möglichkeiten, in Kontakt zu bleiben. http://de.overview.mail.yahoo.com
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by the 2008 JavaOne(SM) Conference
> Don't miss this year's exciting event. There's still time to save $100.
> Use priority code J8TL2D2.
> http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone
> _______________________________________________
> Lksctp-developers mailing list
> Lksctp-developers@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lksctp-developers
>
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2008-04-29 2:03 UTC | newest]
Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-04-29 2:03 [Lksctp-developers] sctp and select Vlad Yasevich
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.