pdu: fix statsn and factor out sn comparision

Signed-off-by: Peter Lieven <pl@kamp.de>

include/iscsi-private.h

@@ -349,11 +349,11 @@ iscsi_log_message(struct iscsi_context *iscsi, int level, const char *format, ..
 void
 iscsi_add_to_outqueue(struct iscsi_context *iscsi, struct iscsi_pdu *pdu);
 
-int
+int iscsi_serial32_compare(uint32_t s1, uint32_t s2);
-iscsi_serial32_compare(uint32_t s1, uint32_t s2);
+void iscsi_adjust_statsn(struct iscsi_context *iscsi, struct iscsi_in_pdu *in);
+void iscsi_adjust_maxexpcmdsn(struct iscsi_context *iscsi, struct iscsi_in_pdu *in);
 
-uint32_t
+uint32_t iscsi_itt_post_increment(struct iscsi_context *iscsi);
-iscsi_itt_post_increment(struct iscsi_context *iscsi);
 
 void iscsi_timeout_scan(struct iscsi_context *iscsi);
 

lib/iscsi-command.c

@@ -347,23 +347,12 @@ int
 iscsi_process_scsi_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 			 struct iscsi_in_pdu *in)
 {
-	uint32_t statsn, maxcmdsn, expcmdsn, flags, status;
+	uint32_t flags, status;
 	struct iscsi_scsi_cbdata *scsi_cbdata = &pdu->scsi_cbdata;
 	struct scsi_task *task = scsi_cbdata->task;
 
-	statsn = scsi_get_uint32(&in->hdr[24]);
+	iscsi_adjust_statsn(iscsi, in);
-	if (statsn > iscsi->statsn) {
+	iscsi_adjust_maxexpcmdsn(iscsi, in);
-		iscsi->statsn = statsn;
-	}
-
-	maxcmdsn = scsi_get_uint32(&in->hdr[32]);
-	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
-		iscsi->maxcmdsn = maxcmdsn;
-	}
-	expcmdsn = scsi_get_uint32(&in->hdr[28]);
-	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
-		iscsi->expcmdsn = expcmdsn;
-	}
 
 	flags = in->hdr[1];
 	if ((flags&ISCSI_PDU_DATA_FINAL) == 0) {
@@ -489,24 +478,13 @@ int
 iscsi_process_scsi_data_in(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 			   struct iscsi_in_pdu *in, int *is_finished)
 {
-	uint32_t statsn, maxcmdsn, expcmdsn, flags, status;
+	uint32_t flags, status;
 	struct iscsi_scsi_cbdata *scsi_cbdata = &pdu->scsi_cbdata;
 	struct scsi_task *task = scsi_cbdata->task;
 	int dsl;
 
-	statsn = scsi_get_uint32(&in->hdr[24]);
+	iscsi_adjust_statsn(iscsi, in);
-	if (statsn > iscsi->statsn) {
+	iscsi_adjust_maxexpcmdsn(iscsi, in);
-		iscsi->statsn = statsn;
-	}
-
-	maxcmdsn = scsi_get_uint32(&in->hdr[32]);
-	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
-		iscsi->maxcmdsn = maxcmdsn;
-	}
-	expcmdsn = scsi_get_uint32(&in->hdr[28]);
-	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
-		iscsi->expcmdsn = expcmdsn;
-	}
 
 	flags = in->hdr[1];
 	if ((flags&ISCSI_PDU_DATA_ACK_REQUESTED) != 0) {
@@ -579,20 +557,13 @@ int
 iscsi_process_r2t(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 			 struct iscsi_in_pdu *in)
 {
-	uint32_t ttt, offset, len, maxcmdsn, expcmdsn;
+	uint32_t ttt, offset, len;
 
 	ttt    = scsi_get_uint32(&in->hdr[20]);
 	offset = scsi_get_uint32(&in->hdr[40]);
 	len    = scsi_get_uint32(&in->hdr[44]);
 
-	maxcmdsn = scsi_get_uint32(&in->hdr[32]);
+	iscsi_adjust_maxexpcmdsn(iscsi, in);
-	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
-		iscsi->maxcmdsn = maxcmdsn;
-	}
-	expcmdsn = scsi_get_uint32(&in->hdr[28]);
-	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
-		iscsi->expcmdsn = expcmdsn;
-	}
 
 	pdu->datasn = 0;
 	iscsi_send_data_out(iscsi, pdu, ttt, offset, len);

lib/login.c

@@ -965,22 +965,14 @@ int
 iscsi_process_login_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 			  struct iscsi_in_pdu *in)
 {
-  uint32_t status, maxcmdsn, expcmdsn;
+	uint32_t status;
 	char *ptr = (char *)in->data;
 	int size = in->data_pos;
 
 	status = scsi_get_uint16(&in->hdr[36]);
 
-	iscsi->statsn = scsi_get_uint16(&in->hdr[24]);
+	iscsi_adjust_statsn(iscsi, in);
-
+	iscsi_adjust_maxexpcmdsn(iscsi, in);
-	maxcmdsn = scsi_get_uint32(&in->hdr[32]);
-	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
-		iscsi->maxcmdsn = maxcmdsn;
-	}
-	expcmdsn = scsi_get_uint32(&in->hdr[28]);
-	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
-		iscsi->expcmdsn = expcmdsn;
-	}
 
 	/* XXX here we should parse the data returned in case the target
 	 * renegotiated some some parameters.
@@ -1176,16 +1168,7 @@ int
 iscsi_process_logout_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 struct iscsi_in_pdu *in)
 {
-  uint32_t maxcmdsn, expcmdsn;
+	iscsi_adjust_maxexpcmdsn(iscsi, in);
-
-	maxcmdsn = scsi_get_uint32(&in->hdr[32]);
-	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
-		iscsi->maxcmdsn = maxcmdsn;
-	}
-	expcmdsn = scsi_get_uint32(&in->hdr[28]);
-	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
-		iscsi->expcmdsn = expcmdsn;
-	}
 
 	iscsi->is_loggedin = 0;
 	pdu->callback(iscsi, SCSI_STATUS_GOOD, NULL, pdu->private_data);

lib/pdu.c

@@ -69,6 +69,31 @@ iscsi_itt_post_increment(struct iscsi_context *iscsi) {
 	return old_itt;
 }
 
+void iscsi_adjust_statsn(struct iscsi_context *iscsi, struct iscsi_in_pdu *in) {
+	uint32_t statsn = scsi_get_uint32(&in->hdr[24]);
+	uint32_t itt = scsi_get_uint32(&in->hdr[16]);
+	
+	if (itt == 0xffffffff) {
+		/* target will not increase statsn if itt == 0xffffffff */
+		statsn--;
+	}
+	
+	if (iscsi_serial32_compare(statsn, iscsi->statsn) > 0) {
+		iscsi->statsn = statsn;
+	}
+}
+
+void iscsi_adjust_maxexpcmdsn(struct iscsi_context *iscsi, struct iscsi_in_pdu *in) {
+	uint32_t maxcmdsn = scsi_get_uint32(&in->hdr[32]);
+	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
+		iscsi->maxcmdsn = maxcmdsn;
+	}
+	uint32_t expcmdsn = scsi_get_uint32(&in->hdr[28]);
+	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
+		iscsi->expcmdsn = expcmdsn;
+	}
+}
+
 void iscsi_dump_pdu_header(struct iscsi_context *iscsi, unsigned char *data) {
 	char dump[ISCSI_RAW_HEADER_SIZE*3+1]={0};
 	int i;
@@ -297,14 +322,10 @@ int iscsi_process_target_nop_in(struct iscsi_context *iscsi,
 				struct iscsi_in_pdu *in)
 {
 	uint32_t ttt;
-	uint32_t statsn;
 
 	ttt = scsi_get_uint32(&in->hdr[20]);
 
-	statsn = scsi_get_uint32(&in->hdr[24]);
+	iscsi_adjust_statsn(iscsi, in);
-	if (statsn > iscsi->statsn) {
-		iscsi->statsn = statsn;
-	}
 
 	/* if the server does not want a response */
 	if (ttt == 0xffffffff) {

lib/task_mgmt.c

@@ -92,18 +92,11 @@ int
 iscsi_process_task_mgmt_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 			    struct iscsi_in_pdu *in)
 {
-	uint32_t response, maxcmdsn, expcmdsn;
+	uint32_t response;
 
 	response = in->hdr[2];
 
-	maxcmdsn = scsi_get_uint32(&in->hdr[32]);
+	iscsi_adjust_maxexpcmdsn(iscsi, in);
-	if (iscsi_serial32_compare(maxcmdsn, iscsi->maxcmdsn) > 0) {
-		iscsi->maxcmdsn = maxcmdsn;
-	}
-	expcmdsn = scsi_get_uint32(&in->hdr[28]);
-	if (iscsi_serial32_compare(expcmdsn, iscsi->expcmdsn) > 0) {
-		iscsi->expcmdsn = expcmdsn;
-	}
 
 	pdu->callback(iscsi, SCSI_STATUS_GOOD, &response, pdu->private_data);