Hi Nab, Thanks for the explanation. Yes the initiator is throwing incorrect TTT. Should not this be handled by the Target?. If this is the valid error, then I would be happy to provide in the patch. Couple of question regarding NOP-In to help me understand the behavior better. (a) When does target (LIO) decide to send out unsolicited NOP-In assuming there will be corresponding NOP-Out (Valid TTT). (b) When target send sout NOP-In without wanting to receive a corresponding NOP-Out.? Thanks, Arshad On 5/23/2014 7:26 AM, Nicholas A. Bellinger wrote: > Hi Arshad, > > On Wed, 2014-05-21 at 14:23 +0530, Arshad Hussain wrote: >> Hi Nab, >> >> This is with reference to RFC 3720 section 10.18. Which stats that the >> unsolicited NOP-in from target as ping should contain valid TTT and this >> should be carried on to NOP-Out. However, I do not see this is >> happening. > Looking at packet #10 in the capture: > > iSCSI (NOP In) > Opcode: NOP In (0x20) > TotalAHSLength: 0x00 > DataSegmentLength: 0x00000000 > LUN: 0000000000000000 > InitiatorTaskTag: 0xffffffff > TargetTransferTag: 0x00000041 > StatSN: 0x0dc061cc > ExpCmdSN: 0x00000042 > MaxCmdSN: 0x00000081 > > The outgoing NopIN PDU from the target does contain a valid TTT + > reserved ITT, as expected for a NOPIN that wants to solicit a NOPOUT > ping from the initiator. > >> The NOP-out is holding the TTT of 0xFFFFFFFF instead of a >> valid TTT. This looks like RFC break in LIO? Please comment. >> >> 10.18. NOP-Out >> >> <SNIP> >> >> Upon receipt of a NOP-In with the Target Transfer Tag set to a valid >> value (not the reserved 0xffffffff), the initiator MUST respond with >> a NOP-Out. In this case, the NOP-Out Target Transfer Tag MUST >> contain a copy of the NOP-In Target Transfer Tag. >> >> I have attached pcap. The concerning frames are 10 and 11. >> > >From there, the NOPOUT ping on the initiator side is incorrect: > > iSCSI (NOP Out) > Opcode: NOP Out (0x00) > .0.. .... = I: Queued delivery > TotalAHSLength: 0x00 > DataSegmentLength: 0x00000000 > LUN: 0000000000000000 > InitiatorTaskTag: 0x00000014 > TargetTransferTag: 0xffffffff > CmdSN: 0x00000000 > ExpStatSN: 0x00000000 > > where the TTT is not echoed from the received NOPIN's TTT, and also > contains a non reserved ITT value. > > --nab > > -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
