Date: Tue, 16 Jun 2009 15:15:45 +0530 (IST) From: saravana perumal <seesaravanan@yahoo.co.in> To: Louis Mamakos <louie@transsys.com> Cc: FreeBSD Mailer List <freebsd-net@freebsd.org> Subject: Re: TCP Free-BSD setup behaviour. Message-ID: <690988.68233.qm@web8320.mail.in.yahoo.com>
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Hi Louie =A0 =A0We are trying to make Active Sync Received state. =A0 As per our testing we are trying to received Syn packet from APPLICATION en= d and to send syn & ACK from Device END and hence reaching the ACTIVE SYN-R= ECEIVED state. =A0 So initially make the application to send SYN sending the Initial SYN and o= nce Received the SYN packet , expecting the Device to Send SYN & ACK =A0 I hope the expectation should be rite in case of ACTIVE-SYN received State. =A0 Thanks. Saravanan =A0 --- On Tue, 6/16/09, Louis Mamakos <louie@transsys.com> wrote: From: Louis Mamakos <louie@transsys.com> Subject: Re: TCP Free-BSD setup behaviour. To: "saravana perumal" <seesaravanan@yahoo.co.in> Cc: freebsd-net@freebsd.org, sarbalas@gmail.com Date: Tuesday, June 16, 2009, 3:05 AM On Jun 15, 2009, at 3:44 AM, saravana perumal wrote: > Hi Louie , >=20 >=20 > Thanks for the Response on my Queries. >=20 > For QUERY 3, > ACTIVE open frm Free BSD end: >=20 >=A0 =A0 =A0 =A0 FREE BSD=A0 =A0 =A0 =A0 =A0 APPLICATION >=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=A0=A0Send ---------> syn >=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=A0=A0Receive <-------- SYN >=20 > Expect SYN & ACK-------------> Getting only ACK in this Scenario, >=20 >=A0 Now Expects FREE BSD to respond back with the SYN & ACK , but BSD is s= ending only ACK message as the response. There's no reason why the FreeBSD host would send another SYN; presumably t= he "APPLICATION" host received the SYN and responds back with SYN of it's o= wn and ACK of the FreeBSD host's SYN.=A0 Once the SYN has been ACK'd, there= 's no reason to resend it.=A0 I suppose I wonder why you expect the FreeBSD= system to retransmit it's SYN? > 4=A0 =A0 .When checking the State - TIME-WAIT=A0 =A0 Sending FIN and expe= cting the ACK ;Getting the ACK properly.=A0=A0=A0Sending Data Segment and E= xpecting the RST signal not getting the RST ; Instead DUT is sending the La= st TCP packet. Issue seen only in Free BSD >=20 >=20 > For this Issue mentioned above, Last TCP packet is jst a Testing packet w= ith the > following Field set=A0 in TIME-WAIT state , >=20 >=20 > TCP: ---- TCP Packet ---- > TCP: > TCP: Source Port=A0 =A0 =A0 =A0 =A0=A0=A0=3D 16815 (16815) > TCP: Destination Port=A0 =A0 =A0 =3D 16816 (16816) > TCP: Sequence Number=A0 =A0 =A0=A0=A0=3D 3865716731 (0xE66A27FB) > TCP: Acknowledgment Number =3D 0 (0x00000000) > TCP: Data Offset=A0 =A0 =A0 =A0 =A0=A0=A0=3D 5 (20 bytes) > TCP: Reserved=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D 0 > TCP: Control Bits=A0 =A0 =A0 =A0 =A0 =3D 0x10 > TCP:=A0 |543210 > TCP:=A0 |0.....=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D Urgent Pointer Isn't Signi= ficant > TCP:=A0 |.1....=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D Acknowledgment Is Signific= ant > TCP:=A0 |..0...=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D No Push Function > TCP:=A0 |...0..=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D No Reset Connection > TCP:=A0 |....0.=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D No Synchronize Sequence Nu= mbers > TCP:=A0 |.....0=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D More Data From Sender > TCP: Window=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D 32752 bytes > TCP: Checksum=A0 =A0 =A0 =A0 =A0 =A0 =A0 =3D 0x41A0 (Correct) > TCP: Urgent Pointer=A0 =A0 =A0 =A0 =3D 0 (Not Significant) > TCP: > TCP: --- Trailing Data [12 bytes] --- > TCP:=A0 53 61 6D 70 6C 65 20 44 61 74 61 00=A0 =A0 =A0 =A0 =A0 =A0 =A0=A0= =A0Sample Data. > TCP: --- Trailing Data End --- > From machine Sending=A0 to the FREE BSD machine, >=20 > This is to verify that Free BSD is in TIME-WAIT state. Not sure what good this packet trace is; the only reason the TCP would resp= ond with a RST segment is if the segment it receives is somehow bogus.=A0 P= erhaps that the send sequence is outside the window.=A0 If the data is with= in the window, it might be considered an "old" segment that happens to arri= ve, perhaps out-of-order; why would the local TCP reset the connection for = no good reason? louie =0A=0A=0A
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