Make it possible to set (via ctl.conf(5)) and query (via ctladm islist -v)

target iSCSI offload.  Add mechanism to query maximum receive data segment
size supported by chosen hardware offload module, and use it in ctld(8)
to determine the value to advertise to the other side.

MFC after:	1 month
Sponsored by:	The FreeBSD Foundation

8 files changed, 106 insertions, 11 deletions

diff --git a/usr.sbin/ctladm/ctladm.c b/usr.sbin/ctladm/ctladm.c
index 03c751b..aefba04 100644
--- a/usr.sbin/ctladm/ctladm.c
+++ b/usr.sbin/ctladm/ctladm.c
@@ -3439,6 +3439,7 @@ struct cctl_islist_conn {
 	char *header_digest;
 	char *data_digest;
 	char *max_data_segment_length;;
+	char *offload;;
 	int immediate_data;
 	int iser;
 	STAILQ_ENTRY(cctl_islist_conn) links;
@@ -3552,6 +3553,9 @@ cctl_islist_end_element(void *user_data, const char *name)
 	} else if (strcmp(name, "max_data_segment_length") == 0) {
 		cur_conn->max_data_segment_length = str;
 		str = NULL;
+	} else if (strcmp(name, "offload") == 0) {
+		cur_conn->offload = str;
+		str = NULL;
 	} else if (strcmp(name, "immediate_data") == 0) {
 		cur_conn->immediate_data = atoi(str);
 	} else if (strcmp(name, "iser") == 0) {
@@ -3672,6 +3676,7 @@ retry:
 			printf("DataSegmentLen:   %s\n", conn->max_data_segment_length);
 			printf("ImmediateData:    %s\n", conn->immediate_data ? "Yes" : "No");
 			printf("iSER (RDMA):      %s\n", conn->iser ? "Yes" : "No");
+			printf("Offload driver:   %s\n", conn->offload);
 			printf("\n");
 		}
 	} else {
diff --git a/usr.sbin/ctld/ctl.conf.5 b/usr.sbin/ctld/ctl.conf.5
index fa053b0..4046998 100644
--- a/usr.sbin/ctld/ctl.conf.5
+++ b/usr.sbin/ctld/ctl.conf.5
@@ -310,6 +310,8 @@ This clause is mutually exclusive with
 .Sy auth-group ;
 one cannot use
 both in a single target.
+.It Ic offload Ar driver
+Define iSCSI hardware offload driver to use for this target.
 .It Ic portal-group Ar name Op Ar agname
 Assign a previously defined portal group to the target.
 The default portal group is
diff --git a/usr.sbin/ctld/ctld.c b/usr.sbin/ctld/ctld.c
index 513e073..dd864b9 100644
--- a/usr.sbin/ctld/ctld.c
+++ b/usr.sbin/ctld/ctld.c
@@ -1272,6 +1272,22 @@ target_set_redirection(struct target *target, const char *addr)
 	return (0);
 }
 
+int
+target_set_offload(struct target *target, const char *offload)
+{
+
+	if (target->t_offload != NULL) {
+		log_warnx("cannot set offload to \"%s\" for "
+		    "target \"%s\"; already defined",
+		    offload, target->t_name);
+		return (1);
+	}
+
+	target->t_offload = checked_strdup(offload);
+
+	return (0);
+}
+
 struct lun *
 lun_new(struct conf *conf, const char *name)
 {
@@ -1514,6 +1530,8 @@ conf_print(struct conf *conf)
 		fprintf(stderr, "target %s {\n", targ->t_name);
 		if (targ->t_alias != NULL)
 			fprintf(stderr, "\t alias %s\n", targ->t_alias);
+		if (targ->t_offload != NULL)
+			fprintf(stderr, "\t offload %s\n", targ->t_offload);
 		fprintf(stderr, "}\n");
 	}
 }
diff --git a/usr.sbin/ctld/ctld.h b/usr.sbin/ctld/ctld.h
index e213e0b..395b014 100644
--- a/usr.sbin/ctld/ctld.h
+++ b/usr.sbin/ctld/ctld.h
@@ -169,6 +169,7 @@ struct target {
 	TAILQ_HEAD(, port)		t_ports;
 	char				*t_name;
 	char				*t_alias;
+	char				*t_offload;
 	char				*t_redirection;
 };
 
@@ -223,6 +224,7 @@ struct connection {
 	struct sockaddr_storage	conn_initiator_sa;
 	uint32_t		conn_cmdsn;
 	uint32_t		conn_statsn;
+	size_t			conn_data_segment_limit;
 	size_t			conn_max_data_segment_length;
 	size_t			conn_max_burst_length;
 	int			conn_immediate_data;
@@ -344,6 +346,8 @@ struct target		*target_find(struct conf *conf,
 			    const char *name);
 int			target_set_redirection(struct target *target,
 			    const char *addr);
+int			target_set_offload(struct target *target,
+			    const char *offload);
 
 struct lun		*lun_new(struct conf *conf, const char *name);
 void			lun_delete(struct lun *lun);
@@ -370,6 +374,8 @@ int			kernel_lun_add(struct lun *lun);
 int			kernel_lun_resize(struct lun *lun);
 int			kernel_lun_remove(struct lun *lun);
 void			kernel_handoff(struct connection *conn);
+void			kernel_limits(const char *offload,
+			    size_t *max_data_segment_length);
 int			kernel_port_add(struct port *port);
 int			kernel_port_update(struct port *port);
 int			kernel_port_remove(struct port *port);
diff --git a/usr.sbin/ctld/kernel.c b/usr.sbin/ctld/kernel.c
index f36bdcb..47dc56a 100644
--- a/usr.sbin/ctld/kernel.c
+++ b/usr.sbin/ctld/kernel.c
@@ -799,6 +799,10 @@ kernel_handoff(struct connection *conn)
 	    sizeof(req.data.handoff.initiator_isid));
 	strlcpy(req.data.handoff.target_name,
 	    conn->conn_target->t_name, sizeof(req.data.handoff.target_name));
+	if (conn->conn_target->t_offload != NULL) {
+		strlcpy(req.data.handoff.offload,
+		    conn->conn_target->t_offload, sizeof(req.data.handoff.offload));
+	}
 #ifdef ICL_KERNEL_PROXY
 	if (proxy_mode)
 		req.data.handoff.connection_id = conn->conn_socket;
@@ -831,6 +835,39 @@ kernel_handoff(struct connection *conn)
 	}
 }
 
+void
+kernel_limits(const char *offload, size_t *max_data_segment_length)
+{
+	struct ctl_iscsi req;
+
+	bzero(&req, sizeof(req));
+
+	req.type = CTL_ISCSI_LIMITS;
+	if (offload != NULL) {
+		strlcpy(req.data.limits.offload, offload,
+		    sizeof(req.data.limits.offload));
+	}
+
+	if (ioctl(ctl_fd, CTL_ISCSI, &req) == -1) {
+		log_err(1, "error issuing CTL_ISCSI ioctl; "
+		    "dropping connection");
+	}
+
+	if (req.status != CTL_ISCSI_OK) {
+		log_errx(1, "error returned from CTL iSCSI limits request: "
+		    "%s; dropping connection", req.error_str);
+	}
+
+	*max_data_segment_length = req.data.limits.data_segment_limit;
+	if (offload != NULL) {
+		log_debugx("MaxRecvDataSegment kernel limit for offload "
+		    "\"%s\" is %zd", offload, *max_data_segment_length);
+	} else {
+		log_debugx("MaxRecvDataSegment kernel limit is %zd",
+		    *max_data_segment_length);
+	}
+}
+
 int
 kernel_port_add(struct port *port)
 {
diff --git a/usr.sbin/ctld/login.c b/usr.sbin/ctld/login.c
index 865a19a..11d97cf 100644
--- a/usr.sbin/ctld/login.c
+++ b/usr.sbin/ctld/login.c
@@ -453,7 +453,8 @@ static void
 login_negotiate_key(struct pdu *request, const char *name,
     const char *value, bool skipped_security, struct keys *response_keys)
 {
-	int which, tmp;
+	int which;
+	size_t tmp;
 	struct connection *conn;
 
 	conn = request->pdu_connection;
@@ -552,13 +553,13 @@ login_negotiate_key(struct pdu *request, const char *name,
 			log_errx(1, "received invalid "
 			    "MaxRecvDataSegmentLength");
 		}
-		if (tmp > MAX_DATA_SEGMENT_LENGTH) {
+		if (tmp > conn->conn_data_segment_limit) {
 			log_debugx("capping MaxRecvDataSegmentLength "
-			    "from %d to %d", tmp, MAX_DATA_SEGMENT_LENGTH);
-			tmp = MAX_DATA_SEGMENT_LENGTH;
+			    "from %zd to %zd", tmp, conn->conn_data_segment_limit);
+			tmp = conn->conn_data_segment_limit;
 		}
 		conn->conn_max_data_segment_length = tmp;
-		keys_add_int(response_keys, name, MAX_DATA_SEGMENT_LENGTH);
+		keys_add_int(response_keys, name, tmp);
 	} else if (strcmp(name, "MaxBurstLength") == 0) {
 		tmp = strtoul(value, NULL, 10);
 		if (tmp <= 0) {
@@ -566,7 +567,7 @@ login_negotiate_key(struct pdu *request, const char *name,
 			log_errx(1, "received invalid MaxBurstLength");
 		}
 		if (tmp > MAX_BURST_LENGTH) {
-			log_debugx("capping MaxBurstLength from %d to %d",
+			log_debugx("capping MaxBurstLength from %zd to %d",
 			    tmp, MAX_BURST_LENGTH);
 			tmp = MAX_BURST_LENGTH;
 		}
@@ -579,10 +580,10 @@ login_negotiate_key(struct pdu *request, const char *name,
 			log_errx(1, "received invalid "
 			    "FirstBurstLength");
 		}
-		if (tmp > MAX_DATA_SEGMENT_LENGTH) {
-			log_debugx("capping FirstBurstLength from %d to %d",
-			    tmp, MAX_DATA_SEGMENT_LENGTH);
-			tmp = MAX_DATA_SEGMENT_LENGTH;
+		if (tmp > conn->conn_data_segment_limit) {
+			log_debugx("capping FirstBurstLength from %zd to %zd",
+			    tmp, conn->conn_data_segment_limit);
+			tmp = conn->conn_data_segment_limit;
 		}
 		/*
 		 * We don't pass the value to the kernel; it only enforces
@@ -680,6 +681,18 @@ login_negotiate(struct connection *conn, struct pdu *request)
 	int i;
 	bool redirected, skipped_security;
 
+	if (conn->conn_session_type == CONN_SESSION_TYPE_NORMAL) {
+		/*
+		 * Query the kernel for MaxDataSegmentLength it can handle.
+		 * In case of offload, it depends on hardware capabilities.
+		 */
+		assert(conn->conn_target != NULL);
+		kernel_limits(conn->conn_target->t_offload,
+		    &conn->conn_data_segment_limit);
+	} else {
+		conn->conn_data_segment_limit = MAX_DATA_SEGMENT_LENGTH;
+	}
+
 	if (request == NULL) {
 		log_debugx("beginning operational parameter negotiation; "
 		    "waiting for Login PDU");
diff --git a/usr.sbin/ctld/parse.y b/usr.sbin/ctld/parse.y
index d0b2c51..5eaffe4 100644
--- a/usr.sbin/ctld/parse.y
+++ b/usr.sbin/ctld/parse.y
@@ -60,7 +60,7 @@ extern void	yyrestart(FILE *);
 %token ALIAS AUTH_GROUP AUTH_TYPE BACKEND BLOCKSIZE CHAP CHAP_MUTUAL
 %token CLOSING_BRACKET DEBUG DEVICE_ID DISCOVERY_AUTH_GROUP DISCOVERY_FILTER
 %token INITIATOR_NAME INITIATOR_PORTAL ISNS_SERVER ISNS_PERIOD ISNS_TIMEOUT
-%token LISTEN LISTEN_ISER LUN MAXPROC OPENING_BRACKET OPTION
+%token LISTEN LISTEN_ISER LUN MAXPROC OFFLOAD OPENING_BRACKET OPTION
 %token PATH PIDFILE PORTAL_GROUP REDIRECT SEMICOLON SERIAL SIZE STR
 %token TARGET TIMEOUT 
 
@@ -463,6 +463,8 @@ target_entry:
 	|
 	target_initiator_portal
 	|
+	target_offload
+	|
 	target_portal_group
 	|
 	target_redirect
@@ -652,6 +654,17 @@ target_initiator_portal:	INITIATOR_PORTAL STR
 	}
 	;
 
+target_offload:	OFFLOAD STR
+	{
+		int error;
+
+		error = target_set_offload(target, $2);
+		free($2);
+		if (error != 0)
+			return (1);
+	}
+	;
+
 target_portal_group:	PORTAL_GROUP STR STR
 	{
 		struct portal_group *tpg;
diff --git a/usr.sbin/ctld/token.l b/usr.sbin/ctld/token.l
index d4bf823..fd27498 100644
--- a/usr.sbin/ctld/token.l
+++ b/usr.sbin/ctld/token.l
@@ -65,6 +65,7 @@ listen			{ return LISTEN; }
 listen-iser		{ return LISTEN_ISER; }
 lun			{ return LUN; }
 maxproc			{ return MAXPROC; }
+offload			{ return OFFLOAD; }
 option			{ return OPTION; }
 path			{ return PATH; }
 pidfile			{ return PIDFILE; }