Hi Arshad,
On Thu, 2014-03-06 at 15:42 +0530, Arshad Hussain wrote:
> Hi,
>
> I am looking for help in understanding how LIO processes/handles NopOUT.
> The problem which I noticed is that LIO Ignores NopOut->flags field
> while processing nop out.
> Looking at RFC Section 10.18 the NopOUT->flags LMB (Left most bit)
> Must be set which LIO is ignoring.
>
> 10.18. NOP-Out
>
> Byte/ 0 | 1 | 2 | 3 |
> / | | | |
> |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
> +---------------+---------------+---------------+---------------+
> 0|.|I| 0x00 |1| Reserved |
> +---------------+---------------+---------------+---------------+
>
> I understand it is the onus of the Initiator to set set proper flags for
> NopOUT,
> However if the initiator fails to set it correctly. This flag is
> ignored, by LIO
> and I understand is a RFC error.
>
> I made changes to the LIO source to confirm my findings. Hope you will find
> my experiments useful.
>
Thanks for the feedback. I'd be happy to take a patch to add the
explicit check for the F_BIT here..
Comments below..
> Thanks
> Arshad
>
> --- ./iscsi_target.c 2014-03-06 02:26:26.830460677 -0500
> +++ ./drivers/target/iscsi/iscsi_target.c 2014-03-06
> 04:04:07.074341573 -0500
> @@ -1568,10 +1568,22 @@
> {
> struct iscsi_cmd *cmd_p = NULL;
> int cmdsn_ret = 0;
> + pr_err("#D1 - Testing if hitting the correct function.\n");
> + pr_err("#D2 - opcode = [%x]\n",hdr->opcode);
> + pr_err("#D3 - flags = [%x]\n",hdr->flags);
> + pr_err("#D3 - TTT = [%x]\n",hdr->ttt);
> /*
> * Initiator is expecting a NopIN ping reply..
> */
>
> + /*
> + * RFC Section 10.18 Mandates NopOUT Flag's LMB to be set
> + */
> + if ( !(hdr->flags & 0x80) ) {
> + pr_err("#D4 - NopOUT Flag LMB not set.\n");
> + return -1;
> + }
> +
So this check should move into iscsit_setup_nop_out(), and should call
iscsit_reject_cmd() with ISCSI_REASON_PROTOCOL_ERROR before returning.
Also, you'll want to use the ISCSI_FLAG_CMD_FINAL macro instead of
hardcoding '0x80' here.
Care to post a proper patch with these comments addressed..?
--nab
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