Re: M3UA: Message Length
"Saxena, Ravi (CMS)" <[email protected]> Fri, 25 Oct 2013 12:34:15 +0000
| Newsgroups | gmane.ietf.sigtran |
|---|---|
| Message-ID | <5D6AD1992F280C46BA6A4931CE2F015208E73E21@G4W3210.americas.hpqcorp.net> |
--===============3062579122123259532== Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_5D6AD1992F280C46BA6A4931CE2F015208E73E21G4W3210americas_" --_000_5D6AD1992F280C46BA6A4931CE2F015208E73E21G4W3210americas_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Message should be discarded, if the length mentioned in the message doesn't= match with the received buffer. We have always seen this behavior. Regards, Ravi Saxena From: [email protected] [mailto:[email protected]] On Behalf = Of David Laight Sent: Monday, October 14, 2013 2:50 PM To: santosh nayak Cc: [email protected] Subject: Re: [Sigtran] M3UA: Message Length I've NFI what you used to take that trace - Wireshark will only give me a h= exdump. Anyway the packet decodes as: Pad, MAC addresses, ethertype 0000 00 00 00 01 00 06 00 1a 30 2b 4b c0 00 00 08 00 IP header 0010 45 02 00 ac 13 31 00 00 fe 84 3f ca 0a 3a 70 c8 0020 0a 3a e3 94 SCTP ports: 0f 53 0f 59 tag: 49 33 5f c5 cksum: 7f 3e b6 8d 0030 chunk type: 00 flags: 03 length: 00 8a TSN: da 58 6c 93 Stream id: 00 01 Stream-seq: 00 08 Payload-id: 00 00 00 03 M3UA data, length 0x7c 0040 01 00 01 01 00 00 00 7c 02 00 00 08 00 00 00 02 0050 00 06 00 08 00 00 00 08 02 10 00 62 00 00 0b ba 0060 00 00 13 8b 03 03 01 00 11 01 03 04 08 0c 45 04 0070 43 8b 13 07 04 43 ba 0b 07 39 00 00 00 00 00 00 0080 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 04 0090 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 00a0 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04 00b0 04 04 04 10 04 40 00 00 00 00 Inter-chunk pad: 00 00 The problem is that the length of the M3UA message (0x7c) is larger than t= he payload part of the SCTP message (0x8a - 0x10 =3D 0x7a). The RFC might let you send that if the M3UA length were 0x7a, but I know th= at all implementations will not be able to receive such messages - so it is be= st not to send them. David From: santosh nayak [mailto:[email protected]] Sent: 14 October 2013 05:47 To: David Laight Subject: Re: [Sigtran] M3UA: Message Length Hi, Thanks for the response... I am attaching the pcap... packet number 85 Could you explain what MUST is violated??? Thanks, Santosh On Thu, Oct 10, 2013 at 5:57 PM, David Laight <[email protected]<mail= to:[email protected]>> wrote: > From: [email protected]<mailto:[email protected]> [mailto:s= [email protected]<mailto:[email protected]>] On Behalf Of Mich= ael Tuexen > On Oct 10, 2013, at 11:40 AM, santosh nayak <[email protected]<ma= ilto:[email protected]>> wrote: > > > Hi, > > > > We have a situation where message is being rejected at M3UA layer due t= o > > buffer length is not equal to message length. > > > > What is the significance of Message Length and its importance with padd= ing... > > > > in the current issue M3UA peer is sending the data buffer of size 122 b= ytes > > to KSCTP. But message length parameter of M3UA common header contains a= value > > of 124 and KSCTP is doing the padding at its level of 2 bytes which is > > observed from the wireshark traces. Are you sure that pad isn't just from SCTP aligning it's chunks? > > Now at DUT message droped with reason (message length parameter is gre= ater > > than actual M3UA data buffer size) > > > > Is this expected??? Please comment on this... > > At least the behaviour of the sender is not expected, since the sender > violates a MUST. I'm not sure what the note in section 3.1.4 is trying to allow, but I think the message you are describing is definitely illegal. I believe that the overall length in the 'common' header should always match that of the SCTP data chunk. This allows M3UA data to be separated into messages when sent using (say) TCP rather than SCTP. I suspect the note allows an implementation to add the pad (following a parameter) when it adds a new one, rather than when it adds a parameter that isn't a multiple of 4 bytes. In any case I'd change your sending end. David Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales) P Please consider the environment and don't print this e-mail unless you re= ally need to --_000_5D6AD1992F280C46BA6A4931CE2F015208E73E21G4W3210americas_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable <html xmlns:v=3D"urn:schemas-microsoft-com:vml" xmlns:o=3D"urn:schemas-micr= osoft-com:office:office" xmlns:w=3D"urn:schemas-microsoft-com:office:word" = xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" xmlns=3D"http:= //www.w3.org/TR/REC-html40"> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii"= > <meta name=3D"Generator" content=3D"Microsoft Word 14 (filtered medium)"> <style><!-- /* Font Definitions */ @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4;} @font-face {font-family:Tahoma; panose-1:2 11 6 4 3 5 4 4 2 4;} @font-face {font-family:"Lucida Console"; panose-1:2 11 6 9 4 5 4 2 2 4;} @font-face {font-family:Webdings; panose-1:5 3 1 2 1 5 9 6 7 3;} @font-face {font-family:"Footlight MT Light"; panose-1:2 4 6 2 6 3 10 2 3 4;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {margin:0in; margin-bottom:.0001pt; font-size:12.0pt; font-family:"Times New Roman","serif";} a:link, span.MsoHyperlink {mso-style-priority:99; color:blue; text-decoration:underline;} a:visited, span.MsoHyperlinkFollowed {mso-style-priority:99; color:purple; text-decoration:underline;} p {mso-style-priority:99; mso-margin-top-alt:auto; margin-right:0in; mso-margin-bottom-alt:auto; margin-left:0in; font-size:12.0pt; font-family:"Times New Roman","serif";} p.MsoAcetate, li.MsoAcetate, div.MsoAcetate {mso-style-priority:99; mso-style-link:"Balloon Text Char"; margin:0in; margin-bottom:.0001pt; font-size:8.0pt; font-family:"Tahoma","sans-serif";} span.hoenzb {mso-style-name:hoenzb;} span.EmailStyle18 {mso-style-type:personal; font-family:"Calibri","sans-serif"; color:#1F497D;} span.EmailStyle21 {mso-style-type:personal-reply; font-family:"Footlight MT Light","serif"; color:blue; font-weight:normal; font-style:normal;} span.BalloonTextChar {mso-style-name:"Balloon Text Char"; mso-style-priority:99; mso-style-link:"Balloon Text"; font-family:"Tahoma","sans-serif";} .MsoChpDefault {mso-style-type:export-only; font-size:10.0pt;} @page WordSection1 {size:8.5in 11.0in; margin:1.0in 1.0in 1.0in 1.0in;} div.WordSection1 {page:WordSection1;} --></style><!--[if gte mso 9]><xml> <o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" /> </xml><![endif]--><!--[if gte mso 9]><xml> <o:shapelayout v:ext=3D"edit"> <o:idmap v:ext=3D"edit" data=3D"1" /> </o:shapelayout></xml><![endif]--> </head> <body lang=3D"EN-US" link=3D"blue" vlink=3D"purple"> <div class=3D"WordSection1"> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue">Message should be discarded, if the len= gth mentioned in the message doesn’t match with the received buffer.<= o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue">We have always seen this behavior.<o:p>= </o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue">Regards,<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue">Ravi Saxena<o:p></o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue"><o:p> </o:p></span></p> <p class=3D"MsoNormal"><span style=3D"font-family:"Footlight MT Light&= quot;,"serif";color:blue"><o:p> </o:p></span></p> <div> <div style=3D"border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in = 0in 0in"> <p class=3D"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:"= ;Tahoma","sans-serif"">From:</span></b><span style=3D"font-s= ize:10.0pt;font-family:"Tahoma","sans-serif""> sigtran-= [email protected] [mailto:[email protected]] <b>On Behalf Of </b>David Laight<br> <b>Sent:</b> Monday, October 14, 2013 2:50 PM<br> <b>To:</b> santosh nayak<br> <b>Cc:</b> [email protected]<br> <b>Subject:</b> Re: [Sigtran] M3UA: Message Length<o:p></o:p></span></p> </div> </div> <p class=3D"MsoNormal"><o:p> </o:p></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">I’ve= NFI what you used to take that trace – Wireshark will only give me a= hexdump.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">Anyway the= packet decodes as:<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console""><o:p> = </o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">Pad, MAC ad= dresses, ethertype<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0000 = 00 00 00 01 00 06 00 1a 30 2b 4b c0 00 00 08 00<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">IP header<o= :p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0010 = 45 02 00 ac 13 31 00 00 fe 84 3f ca 0a 3a 70 c8<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0020 = 0a 3a e3 94<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">SCTP<o:p></= o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; ports: 0f 53 0f 59<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; tag: 49 33 5f c5<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; cksum: 7f 3e b6 8d<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0030 = chunk type: 00<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; flags: 03<o:p></o:p></spa= n></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; length: 00 8a<o:p></o:p></span>= </p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; TSN: da 58 6c= 93<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; Stream id: 00 01<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; Stream-seq: 00 08<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; Payload-id: 00 00 00 03<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console""><o:p> = </o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">M3UA data, = length 0x7c<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0040 = 01 00 01 01 00 00 00 7c<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; 02 00 00 08<o:p></o= :p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; &n= bsp; 00 00 00 02<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0050 &= nbsp; 00 06 00 08<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; &n= bsp; 00 00 00 08<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; 02 10 00 62<o:p></o= :p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">  = ; &n= bsp; 00 00 0b ba<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0060 &= nbsp; 00 = 00 13 8b 03 03 01 00 11 01 03 04 08 0c 45 04<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0070 &= nbsp; 43 = 8b 13 07 04 43 ba 0b 07 39 00 00 00 00 00 00<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0080 &= nbsp; 00 = 00 00 00 00 00 00 00 00 00 00 00 00 00 04 04<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">0090 &= nbsp; 04 = 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">00a0 &= nbsp; 04 = 04 04 04 04 04 04 04 04 04 04 04 04 04 04 04<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">00b0 &= nbsp; 04 = 04 04 10 04 40 00 00 00 00<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console""><o:p> = </o:p></span></p> <p class=3D"MsoNormal" style=3D"text-autospace:none"><span lang=3D"EN-GB" s= tyle=3D"font-size:9.0pt;font-family:"Lucida Console"">Inter-chunk= pad: 00 00<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D"><o:p> = ;</o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">The proble= m is that the length of the M3UA message (0x7c) is larger than the pa= yload<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">part of th= e SCTP message (0x8a – 0x10 =3D 0x7a).<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">The RFC mi= ght let you send that if the M3UA length were 0x7a, but I know that<o:p></o= :p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">all implem= entations will not be able to receive such messages – so it is best n= ot<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D">to send th= em.<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D"><o:p> = ;</o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D"> &nbs= p; &= nbsp; David<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D"><o:p> = ;</o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:11.0pt;font-= family:"Calibri","sans-serif";color:#1F497D"><o:p> = ;</o:p></span></p> <div style=3D"border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in = 4.0pt"> <div> <div style=3D"border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in = 0in 0in"> <p class=3D"MsoNormal"><b><span style=3D"font-size:10.0pt;font-family:"= ;Tahoma","sans-serif"">From:</span></b><span style=3D"font-s= ize:10.0pt;font-family:"Tahoma","sans-serif""> santosh = nayak [mailto:[email protected]] <br> <b>Sent:</b> 14 October 2013 05:47<br> <b>To:</b> David Laight<br> <b>Subject:</b> Re: [Sigtran] M3UA: Message Length<o:p></o:p></span></p> </div> </div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">Hi,<o:p></o:p></span></p> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">Thanks for the response...<o:p>= </o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">I am attaching the pcap... pack= et number 85<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">Could you explain what MUST is = violated???<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">Thanks,<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">Santosh<o:p></o:p></span></p> </div> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> </div> </div> <div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span lang=3D"EN-GB">= <o:p> </o:p></span></p> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">On Thu, Oct 10, 2013 at 5:57 PM= , David Laight <<a href=3D"mailto:[email protected]" target=3D"_bl= ank">[email protected]</a>> wrote:<o:p></o:p></span></p> <p class=3D"MsoNormal"><span lang=3D"EN-GB">> From: <a href=3D"mailto:si= [email protected]"> [email protected]</a> [mailto:<a href=3D"mailto:sigtran-bounces@ietf= .org">[email protected]</a>] On Behalf Of Michael Tuexen<o:p></o:p><= /span></p> <div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span lang=3D"EN-GB">= > On Oct 10, 2013, at 11:40 AM, santosh nayak <<a href=3D"mailto:sant= [email protected]">[email protected]</a>> wrote:<br> ><br> > > Hi,<br> > ><br> > > We have a situation where message is being rejected at M3UA layer= due to<br> > > buffer length is not equal to message length.<br> > ><br> > > What is the significance of Message Length and its importance wit= h padding...<br> > ><br> > > in the current issue M3UA peer is sending the data buffer of size= 122 bytes<br> > > to KSCTP. But message length parameter of M3UA common header cont= ains a value<br> > > of 124 and KSCTP is doing the padding at its level of 2 bytes whi= ch is<br> > > observed from the wireshark traces.<o:p></o:p></span></p> </div> <p class=3D"MsoNormal"><span lang=3D"EN-GB">Are you sure that pad isn't jus= t from SCTP aligning it's chunks?<o:p></o:p></span></p> <div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span lang=3D"EN-GB">= <br> > > Now at DUT message droped with reason (message length param= eter is greater<br> > > than actual M3UA data buffer size)<br> > ><br> > > Is this expected??? Please comment on this...<br> ><br> > At least the behaviour of the sender is not expected, since the sender= <br> > violates a MUST.<o:p></o:p></span></p> </div> <p class=3D"MsoNormal" style=3D"margin-bottom:12.0pt"><span lang=3D"EN-GB">= I'm not sure what the note in section 3.1.4 is trying to allow, but<br> I think the message you are describing is definitely illegal.<br> <br> I believe that the overall length in the 'common' header should always<br> match that of the SCTP data chunk.<br> This allows M3UA data to be separated into messages when sent using (say)<b= r> TCP rather than SCTP.<br> <br> I suspect the note allows an implementation to add the pad (following a<br> parameter) when it adds a new one, rather than when it adds a parameter<br> that isn't a multiple of 4 bytes.<br> <br> In any case I'd change your sending end.<br> <span style=3D"color:#888888"><br> <span class=3D"hoenzb"> David</span><br> <br> </span><o:p></o:p></span></p> </div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> </div> </div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> <div> <p class=3D"MsoNormal"><span lang=3D"EN-GB" style=3D"font-size:7.5pt;font-f= amily:"Tahoma","sans-serif";color:#484830">Registered A= ddress Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK<br> Registration No: 1397386 (Wales)</span><span lang=3D"EN-GB"><o:p></o:p></sp= an></p> </div> <div> <p align=3D"center" style=3D"text-align:center"><span lang=3D"EN-GB" style= =3D"font-size:7.5pt;font-family:Webdings;color:green">P<strong><span style= =3D"font-family:Webdings"> </span></strong></span><strong><span lang=3D"EN-GB" style=3D"font-size:7.5p= t;font-family:"Arial","sans-serif";color:green">Please = consider the environment and don't print this e-mail unless you really need= to</span></strong><span lang=3D"EN-GB" style=3D"font-size:18.0pt;font-fami= ly:Webdings;color:green"><o:p></o:p></span></p> </div> <p class=3D"MsoNormal"><span lang=3D"EN-GB"><o:p> </o:p></span></p> </div> </body> </html> --_000_5D6AD1992F280C46BA6A4931CE2F015208E73E21G4W3210americas_-- --===============3062579122123259532== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Sigtran mailing list [email protected] https://www.ietf.org/mailman/listinfo/sigtran --===============3062579122123259532==--