[Stgt-devel] [PATCH 16/18] iser params

[Pete Wyckoff]

Add iSCSI parameters as defined in the draft iSER specification.
Handle special parameter cases for RDMA:

    - no digests
    - do not offer iSER parameters unless initiator requests them
    - do not offer MRDSL (use [IT]RDSL instead)

Except do not advertise MaxOutstandingUnexpectedPDUs just yet, as
the open-iscsi initiatior does not understand it.

Signed-off-by: Pete Wyckoff <pw at osc.edu>
---
 usr/iscsi/iscsi_if.h |    5 +++++
 usr/iscsi/iscsid.c   |   21 ++++++++++++++++++++-
 usr/iscsi/param.c    |   38 ++++++++++++++++++++++++++++++++++++++
 usr/iscsi/target.c   |    8 ++++++++
 4 files changed, 71 insertions(+), 1 deletions(-)

diff --git a/usr/iscsi/iscsi_if.h b/usr/iscsi/iscsi_if.h
index 58a76a2..b4f1e04 100644
--- a/usr/iscsi/iscsi_if.h
+++ b/usr/iscsi/iscsi_if.h
@@ -215,6 +215,11 @@ enum iscsi_param {
 	ISCSI_PARAM_OFMARKINT,
 	ISCSI_PARAM_IFMARKINT,
 	ISCSI_PARAM_MAXCONNECTIONS,
+	/* iSER draft */
+	ISCSI_PARAM_RDMA_EXTENSIONS,
+	ISCSI_PARAM_TARGET_RDSL,
+	ISCSI_PARAM_INITIATOR_RDSL,
+	ISCSI_PARAM_MAX_OUTST_PDU,
 	/* must always be last */
 	ISCSI_PARAM_MAX,
 };
diff --git a/usr/iscsi/iscsid.c b/usr/iscsi/iscsid.c
index 05ca46b..fd9f8f2 100644
--- a/usr/iscsi/iscsid.c
+++ b/usr/iscsi/iscsid.c
@@ -270,7 +270,7 @@ static void login_security_done(struct iscsi_connection *conn)
 static void text_scan_login(struct iscsi_connection *conn)
 {
 	char *key, *value, *data;
-	int datasize, idx;
+	int datasize, idx, is_rdma = 0;
 	struct iscsi_login_rsp *rsp = (struct iscsi_login_rsp *)&conn->rsp.bhs;
 
 	data = conn->req.data;
@@ -291,6 +291,9 @@ static void text_scan_login(struct iscsi_connection *conn)
 				conn->mxdsl_negotiated = 1;
 			}
 
+			if (idx == ISCSI_PARAM_RDMA_EXTENSIONS)
+				is_rdma = 1;
+
 			if (param_str_to_val(session_keys, idx, value, &val) < 0) {
 				if (conn->session_param[idx].state
 				    == KEY_STATE_START) {
@@ -337,6 +340,15 @@ static void text_scan_login(struct iscsi_connection *conn)
 			text_key_add(conn, key, "NotUnderstood");
 	}
 
+	if (is_rdma) {
+		/* do not try to do digests, not supported in iser */
+		conn->session_param[ISCSI_PARAM_HDRDGST_EN].val = DIGEST_NONE;
+		conn->session_param[ISCSI_PARAM_DATADGST_EN].val = DIGEST_NONE;
+	} else {
+		/* do not offer RDMA, initiator must explicitly request */
+		conn->session_param[ISCSI_PARAM_RDMA_EXTENSIONS].val = 0;
+	}
+
 out:
 	return;
 }
@@ -354,6 +366,13 @@ static int text_check_param(struct iscsi_connection *conn)
 					p[i].state = KEY_STATE_DONE;
 					continue;
 				}
+				if (p[ISCSI_PARAM_RDMA_EXTENSIONS].val == 1) {
+					if (i == ISCSI_PARAM_MAX_RECV_DLENGTH)
+						continue;
+				} else {
+					if (i >= ISCSI_PARAM_RDMA_EXTENSIONS)
+						continue;
+				}
 				memset(buf, 0, sizeof(buf));
 				param_val_to_str(session_keys, i, p[i].val,
 						 buf);
diff --git a/usr/iscsi/param.c b/usr/iscsi/param.c
index 9eac62c..76236d1 100644
--- a/usr/iscsi/param.c
+++ b/usr/iscsi/param.c
@@ -118,6 +118,18 @@ static int minimum_check_val(struct iscsi_key *key, unsigned int *val)
 	return 0;
 }
 
+static int min_or_zero_check_val(struct iscsi_key *key, unsigned int *val)
+{
+	int err = 0;
+
+	if (*val != 0 && (*val < key->min || key->max < *val)) {
+		*val = key->min;
+		err = -EINVAL;
+	}
+
+	return 0;
+}
+
 static int maximum_check_val(struct iscsi_key *key, unsigned int *val)
 {
 	int err = 0;
@@ -140,6 +152,16 @@ static int minimum_set_val(struct param *param, int idx, unsigned int *val)
 	return 0;
 }
 
+static int min_or_zero_set_val(struct param *param, int idx, unsigned int *val)
+{
+	if (*val > param[idx].val || *val == 0)
+		*val = param[idx].val;
+	else
+		param[idx].val = *val;
+
+	return 0;
+}
+
 static int maximum_set_val(struct param *param, int idx, unsigned int *val)
 {
 	if (param[idx].val > *val)
@@ -265,6 +287,13 @@ static struct iscsi_key_ops minimum_ops = {
 	.set_val = minimum_set_val,
 };
 
+static struct iscsi_key_ops min_or_zero_ops = {
+	.val_to_str = range_val_to_str,
+	.str_to_val = range_str_to_val,
+	.check_val = min_or_zero_check_val,
+	.set_val = min_or_zero_set_val,
+};
+
 static struct iscsi_key_ops maximum_ops = {
 	.val_to_str = range_val_to_str,
 	.str_to_val = range_str_to_val,
@@ -345,6 +374,15 @@ struct iscsi_key session_keys[] = {
 	{"IFMarkInt", 2048, 1, 65535, &marker_ops},
 	[ISCSI_PARAM_MAXCONNECTIONS] =
 	{"MaxConnections", 1, 1, 65535, &minimum_ops},
+	/* iSER draft */
+	[ISCSI_PARAM_RDMA_EXTENSIONS] =
+	{"RDMAExtensions", 0, 0, 1, &and_ops},
+	[ISCSI_PARAM_TARGET_RDSL] =
+	{"TargetRecvDataSegmentLength", 8192, 512, 16777215, &minimum_ops},
+	[ISCSI_PARAM_INITIATOR_RDSL] =
+	{"InitiatorRecvDataSegmentLength", 8192, 512, 16777215, &minimum_ops},
+	[ISCSI_PARAM_MAX_OUTST_PDU] =
+	{"MaxOutstandingUnexpectedPDUs", 0, 2, 4294967295U, &min_or_zero_ops},
 	[ISCSI_PARAM_MAX] =
 	{NULL,},
 };
diff --git a/usr/iscsi/target.c b/usr/iscsi/target.c
index 3ddb2d7..61da4e2 100644
--- a/usr/iscsi/target.c
+++ b/usr/iscsi/target.c
@@ -283,6 +283,14 @@ int iscsi_target_create(struct target *t)
 		[ISCSI_PARAM_OFMARKINT] = {0, 2048},
 		[ISCSI_PARAM_IFMARKINT] = {0, 2048},
 		[ISCSI_PARAM_MAXCONNECTIONS] = {0, 1},
+#ifdef ISCSI_RDMA
+		[ISCSI_PARAM_RDMA_EXTENSIONS] = {0, 1},
+#else
+		[ISCSI_PARAM_RDMA_EXTENSIONS] = {0, 0},
+#endif
+		[ISCSI_PARAM_TARGET_RDSL] = {0, 262144},
+		[ISCSI_PARAM_INITIATOR_RDSL] = {0, 262144},
+		[ISCSI_PARAM_MAX_OUTST_PDU] =  {0, 0},  /* not in open-iscsi */
 	};
 
 	target = malloc(sizeof(*target));
-- 
1.5.2.5