>-----Original Message-----
>From: Joe Eykholt [mailto:[email protected]]
>Sent: Wednesday, July 15, 2009 2:40 PM
>To: Ma, Steve
>Cc: [email protected]
>Subject: Re: [Open-FCoE] [PATCH] libfc: Validating SOF, EOF, SEQ_ID,
>SEQ_CNT, f_ctl for response frames
>
>Steve Ma wrote:
>> This patch is for handling the received frames where the other end
>> is originating the sequence in response to the exchange originated
>> by the initiator.
>>
>> The current code is weak in validation of SOF,EOF,SEQ_ID,SEQ_CNT,f_ctl
>> for response frames, or no validations for SEQ_CNT.
>>
>> This patch is to add code to perform the validations of f_ctl in the
>> frame header for FC_FC_LAST_SEQ, FC_FC_END_SEQ, and FC_FC_SEQ_INIT
>> bits. The frame will be dropped (i.e. freed) if it fails the validation.
>>
>> Signed-off-by: Steve Ma <[email protected]>
>> ---
>>
>> drivers/scsi/libfc/fc_exch.c | 59
>++++++++++++++++++++++++++++++++++++------
>> 1 files changed, 51 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
>> index f42695e..d86eda8 100644
>> --- a/drivers/scsi/libfc/fc_exch.c
>> +++ b/drivers/scsi/libfc/fc_exch.c
>> @@ -1124,7 +1124,9 @@ static void fc_exch_recv_seq_resp(struct
>fc_exch_mgr *mp, struct fc_frame *fp)
>> struct fc_seq *sp;
>> struct fc_exch *ep;
>> enum fc_sof sof;
>> + enum fc_eof eof;
>> u32 f_ctl;
>> + u16 cnt;
>> void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
>> void *ex_resp_arg;
>> int rc;
>> @@ -1149,29 +1151,70 @@ static void fc_exch_recv_seq_resp(struct
>fc_exch_mgr *mp, struct fc_frame *fp)
>> atomic_inc(&mp->stats.xid_not_found);
>> goto rel;
>> }
>> +
>> sof = fr_sof(fp);
>> - if (fc_sof_is_init(sof)) {
>> + eof = fr_eof(fp);
>> + cnt = ntohs(fh->fh_seq_cnt);
>> + f_ctl = ntoh24(fh->fh_f_ctl);
>> +
>> + if ((sof == FC_SOF_I3 && eof == FC_EOF_T)) {
>
>Remove extra parens and extra space after the first ==.
>
> if (sof == FC_SOF_I3 && eof == FC_EOF_T) {
>
>> + /* first and last frame in a sequence */
>> sp = fc_seq_start_next(&ep->seq);
>> + if ((cnt && (cnt != sp->cnt + 1)) ||
>> + (!(f_ctl & FC_FC_END_SEQ))) {
>
>Since it's the only frame of the sequence, shouldn't cnt be zero?
Because the sequence may not be the first sequence of the exchange, the SEQ_CNT
can be either zero or continuously increasing. FC-FS-2, 9.10.
>
> if (!cnt || !(f_ctl & FC_FC_END_SEQ)) {
>
>Avoid extra parens.
>
>> + atomic_inc(&mp->stats.seq_not_found);
>> + goto rel;
>> + }
>> + sp->cnt = cnt;
>> sp->id = fh->fh_seq_id;
>> sp->ssb_stat |= SSB_ST_RESP;
>> - } else {
>> + ep->esb_stat |= ESB_ST_SEQ_INIT;
>> + } else if ((sof == FC_SOF_I3 && eof == FC_EOF_N)) {
>
>remove extra parens and extra space after first ==
>
>> + /* first and not last frame in a sequence */
>> + sp = fc_seq_start_next(&ep->seq);
>> + if ((cnt && (cnt != sp->cnt + 1)) ||
>
>Again, shouldn't cnt be zero?
>
Same as above.
>> + (f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ||
>
>LAST_SEQ is allowed on any frame in the last sequence, although
>it is only required on the last frame. So, don't check that here.
>See FC-FS-2, section 9.7.5.
>
>> + (f_ctl & FC_FC_SEQ_INIT)) {
>> + atomic_inc(&mp->stats.seq_not_found);
>> + goto rel;
>> + }
>> + sp->cnt = cnt;
>> + sp->id = fh->fh_seq_id;
>> + sp->ssb_stat |= SSB_ST_RESP;
>> + ep->esb_stat |= ESB_ST_SEQ_INIT;
>> + } else if ((sof == FC_SOF_N3) && (eof == FC_EOF_N)) {
>> + /* middle frame in a sequence */
>> sp = &ep->seq;
>> - if (sp->id != fh->fh_seq_id) {
>> + if ((sp->id != fh->fh_seq_id) ||
>> + (sp->cnt + 1 != cnt) ||
>> + (f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ||
>> + (f_ctl & FC_FC_SEQ_INIT)) {
>
>Don't check LAST_SEQ here, either.
>Suggest removing extra parens around comparisons.
>
>> + atomic_inc(&mp->stats.seq_not_found);
>> + goto rel;
>> + }
>> + sp->cnt++;
>> + } else if ((sof == FC_SOF_N3) && (eof == FC_EOF_T)) {
>> + /* last frame in a sequence */
>> + sp = &ep->seq;
>> + if ((sp->id != fh->fh_seq_id) ||
>> + (sp->cnt + 1 != cnt) ||
>
>We do see reordering of frames for FCP when interrupt
>migration moves the receive interrupt to another CPU.
>So the sequence comparison shouldn't be done unless we somehow
>figure out how to preserve order in this case.
>
>BTW, the only non-FCP sequences that we handle as multiple frames
>are CT GPN_FT responses. fc_disc.c already checks that they
>arrive in order, so we really don't need to check it here.
>
I have also seen multiple response frames when sending ECHO of 256 bytes to a
SANBlaze target.
>> + (!(f_ctl & FC_FC_END_SEQ))) {
>> atomic_inc(&mp->stats.seq_not_found);
>> goto rel;
>> }
>> + sp->cnt++;
>
>Need to test for SEQ_INIT here, too.
>
>> + } else {
>> + atomic_inc(&mp->stats.seq_not_found);
>> + goto rel;
>> }
>> - f_ctl = ntoh24(fh->fh_f_ctl);
>> - fr_seq(fp) = sp;
>> - if (f_ctl & FC_FC_SEQ_INIT)
>> - ep->esb_stat |= ESB_ST_SEQ_INIT;
>>
>> + fr_seq(fp) = sp;
>> if (fc_sof_needs_ack(sof))
>> fc_seq_send_ack(sp, fp);
>> resp = ep->resp;
>> ex_resp_arg = ep->arg;
>>
>> - if (fh->fh_type != FC_TYPE_FCP && fr_eof(fp) == FC_EOF_T &&
>> + if (fh->fh_type != FC_TYPE_FCP && eof == FC_EOF_T &&
>> (f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ==
>> (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) {
>> spin_lock_bh(&ep->ex_lock);
>>
>> _______________________________________________
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