Index: head/sys/dev/iscsi/iscsi_ioctl.h
===================================================================
--- head/sys/dev/iscsi/iscsi_ioctl.h
+++ head/sys/dev/iscsi/iscsi_ioctl.h
@@ -70,7 +70,8 @@
 	int		isc_iser;
 	char		isc_offload[ISCSI_OFFLOAD_LEN];
 	int		isc_enable;
-	int		isc_spare[4];
+	int		isc_dscp;
+	int		isc_spare[3];
 };
 
 /*
Index: head/usr.bin/iscsictl/Makefile
===================================================================
--- head/usr.bin/iscsictl/Makefile
+++ head/usr.bin/iscsictl/Makefile
@@ -7,7 +7,7 @@
 CFLAGS+=	-I${SRCTOP}/sys/dev/iscsi
 MAN=		iscsi.conf.5 iscsictl.8
 
-LIBADD=		xo
+LIBADD=		util xo
 
 YFLAGS+=	-v
 LFLAGS+=	-i
Index: head/usr.bin/iscsictl/iscsi.conf.5
===================================================================
--- head/usr.bin/iscsictl/iscsi.conf.5
+++ head/usr.bin/iscsictl/iscsi.conf.5
@@ -145,6 +145,16 @@
 .Qq Ar iSCSI .
 Default is
 .Qq Ar iSCSI .
+.It Cm dscp
+The DiffServ Codepoint used for sending data. The DSCP can be
+set to numeric, or hexadecimal values directly, as well as the
+well-defined
+.Qq Ar cs<n>
+and
+.Qq Ar af<xx>
+codepoints.
+Default is no specified dscp codepoint, which means the default
+of the outgoing interface is used.
 .El
 .Sh FILES
 .Bl -tag -width indent
Index: head/usr.bin/iscsictl/iscsictl.h
===================================================================
--- head/usr.bin/iscsictl/iscsictl.h
+++ head/usr.bin/iscsictl/iscsictl.h
@@ -78,6 +78,7 @@
 	int			t_session_type;
 	int			t_enable;
 	int			t_protocol;
+	int			t_dscp;
 	char			*t_offload;
 	char			*t_user;
 	char			*t_secret;
Index: head/usr.bin/iscsictl/iscsictl.c
===================================================================
--- head/usr.bin/iscsictl/iscsictl.c
+++ head/usr.bin/iscsictl/iscsictl.c
@@ -87,6 +87,7 @@
 	if (targ == NULL)
 		xo_err(1, "calloc");
 	targ->t_conf = conf;
+	targ->t_dscp = -1;
 	TAILQ_INSERT_TAIL(&conf->conf_targets, targ, t_next);
 
 	return (targ);
@@ -358,6 +359,7 @@
 		conf->isc_data_digest = ISCSI_DIGEST_CRC32C;
 	else
 		conf->isc_data_digest = ISCSI_DIGEST_NONE;
+	conf->isc_dscp = targ->t_dscp;
 }
 
 static int
@@ -535,6 +537,9 @@
 			    "Target portal:", conf->isc_target_addr);
 			xo_emit("{L:/%-26s}{V:alias/%s}\n",
 			    "Target alias:", state->iss_target_alias);
+			if (conf->isc_dscp != -1)
+				xo_emit("{L:/%-26s}{V:dscp/0x%02x}\n",
+				    "Target DSCP:", conf->isc_dscp);
 			xo_close_container("target");
 
 			xo_open_container("auth");
Index: head/usr.bin/iscsictl/parse.y
===================================================================
--- head/usr.bin/iscsictl/parse.y
+++ head/usr.bin/iscsictl/parse.y
@@ -44,6 +44,8 @@
 #include <libxo/xo.h>
 
 #include "iscsictl.h"
+#include <netinet/in.h>
+#include <netinet/ip.h>
 
 extern FILE *yyin;
 extern char *yytext;
@@ -61,7 +63,9 @@
 %token AUTH_METHOD ENABLE HEADER_DIGEST DATA_DIGEST TARGET_NAME TARGET_ADDRESS
 %token INITIATOR_NAME INITIATOR_ADDRESS INITIATOR_ALIAS USER SECRET
 %token MUTUAL_USER MUTUAL_SECRET SEMICOLON SESSION_TYPE PROTOCOL OFFLOAD
-%token IGNORED EQUALS OPENING_BRACKET CLOSING_BRACKET
+%token IGNORED EQUALS OPENING_BRACKET CLOSING_BRACKET DSCP
+%token AF11 AF12 AF13 AF21 AF22 AF23 AF31 AF32 AF33 AF41 AF42 AF43
+%token BE EF CS0 CS1 CS2 CS3 CS4 CS5 CS6 CS7
 
 %union
 {
@@ -127,6 +131,8 @@
 	protocol
 	|
 	ignored
+	|
+	dscp
 	;
 
 target_name:	TARGET_NAME EQUALS STR
@@ -294,6 +300,48 @@
 	{
 		xo_warnx("obsolete statement ignored at line %d", lineno);
 	}
+	;
+
+dscp:		DSCP EQUALS STR
+	{
+		uint64_t tmp;
+
+		if (strcmp($3, "0x") == 0) {
+			tmp = strtol($3 + 2, NULL, 16);
+		} else if (expand_number($3, &tmp) != 0) {
+			yyerror("invalid numeric value");
+			free($3);
+			return(1);
+		}
+		if (tmp >= 0x40) {
+			yyerror("invalid dscp value");
+			return(1);
+		}
+
+		target->t_dscp = tmp;
+	}
+	| DSCP EQUALS BE	{ target->t_dscp = IPTOS_DSCP_CS0  >> 2 ; }
+	| DSCP EQUALS EF	{ target->t_dscp = IPTOS_DSCP_EF   >> 2 ; }
+	| DSCP EQUALS CS0	{ target->t_dscp = IPTOS_DSCP_CS0  >> 2 ; }
+	| DSCP EQUALS CS1	{ target->t_dscp = IPTOS_DSCP_CS1  >> 2 ; }
+	| DSCP EQUALS CS2	{ target->t_dscp = IPTOS_DSCP_CS2  >> 2 ; }
+	| DSCP EQUALS CS3	{ target->t_dscp = IPTOS_DSCP_CS3  >> 2 ; }
+	| DSCP EQUALS CS4	{ target->t_dscp = IPTOS_DSCP_CS4  >> 2 ; }
+	| DSCP EQUALS CS5	{ target->t_dscp = IPTOS_DSCP_CS5  >> 2 ; }
+	| DSCP EQUALS CS6	{ target->t_dscp = IPTOS_DSCP_CS6  >> 2 ; }
+	| DSCP EQUALS CS7	{ target->t_dscp = IPTOS_DSCP_CS7  >> 2 ; }
+	| DSCP EQUALS AF11	{ target->t_dscp = IPTOS_DSCP_AF11 >> 2 ; }
+	| DSCP EQUALS AF12	{ target->t_dscp = IPTOS_DSCP_AF12 >> 2 ; }
+	| DSCP EQUALS AF13	{ target->t_dscp = IPTOS_DSCP_AF13 >> 2 ; }
+	| DSCP EQUALS AF21	{ target->t_dscp = IPTOS_DSCP_AF21 >> 2 ; }
+	| DSCP EQUALS AF22	{ target->t_dscp = IPTOS_DSCP_AF22 >> 2 ; }
+	| DSCP EQUALS AF23	{ target->t_dscp = IPTOS_DSCP_AF23 >> 2 ; }
+	| DSCP EQUALS AF31	{ target->t_dscp = IPTOS_DSCP_AF31 >> 2 ; }
+	| DSCP EQUALS AF32	{ target->t_dscp = IPTOS_DSCP_AF32 >> 2 ; }
+	| DSCP EQUALS AF33	{ target->t_dscp = IPTOS_DSCP_AF33 >> 2 ; }
+	| DSCP EQUALS AF41	{ target->t_dscp = IPTOS_DSCP_AF41 >> 2 ; }
+	| DSCP EQUALS AF42	{ target->t_dscp = IPTOS_DSCP_AF42 >> 2 ; }
+	| DSCP EQUALS AF43	{ target->t_dscp = IPTOS_DSCP_AF43 >> 2 ; }
 	;
 
 %%
Index: head/usr.bin/iscsictl/token.l
===================================================================
--- head/usr.bin/iscsictl/token.l
+++ head/usr.bin/iscsictl/token.l
@@ -68,6 +68,7 @@
 protocol		{ return PROTOCOL; }
 offload			{ return OFFLOAD; }
 port			{ return IGNORED; }
+dscp			{ return DSCP; }
 MaxConnections		{ return IGNORED; }
 TargetAlias		{ return IGNORED; }
 TargetPortalGroupTag	{ return IGNORED; }
@@ -86,6 +87,28 @@
 maxluns			{ return IGNORED; }
 sockbufsize		{ return IGNORED; }
 chapDigest		{ return IGNORED; }
+af11			{ return AF11; }
+af12			{ return AF12; }
+af13			{ return AF13; }
+af21			{ return AF21; }
+af22			{ return AF22; }
+af23			{ return AF23; }
+af31			{ return AF31; }
+af32			{ return AF32; }
+af33			{ return AF33; }
+af41			{ return AF41; }
+af42			{ return AF42; }
+af43			{ return AF43; }
+be			{ return CS0;  }
+ef			{ return EF;   }
+cs0			{ return CS0;  }
+cs1			{ return CS1;  }
+cs2			{ return CS2;  }
+cs3			{ return CS3;  }
+cs4			{ return CS4;  }
+cs5			{ return CS5;  }
+cs6			{ return CS6;  }
+cs7			{ return CS7;  }
 \"[^"]+\"		{ yylval.str = strndup(yytext + 1,
 			    strlen(yytext) - 2); return STR; }
 [a-zA-Z0-9\.\-_/\:\[\]]+ { yylval.str = strdup(yytext); return STR; }
Index: head/usr.sbin/iscsid/iscsid.c
===================================================================
--- head/usr.sbin/iscsid/iscsid.c
+++ head/usr.sbin/iscsid/iscsid.c
@@ -41,6 +41,7 @@
 #include <sys/socket.h>
 #include <sys/capsicum.h>
 #include <sys/wait.h>
+#include <netinet/in.h>
 #include <assert.h>
 #include <capsicum_helpers.h>
 #include <errno.h>
@@ -276,6 +277,25 @@
 	if (setsockopt(conn->conn_socket, SOL_SOCKET, SO_SNDBUF,
 	    &sockbuf, sizeof(sockbuf)) == -1)
 		log_warn("setsockopt(SO_SNDBUF) failed");
+	if (conn->conn_conf.isc_dscp != -1) {
+		int tos = conn->conn_conf.isc_dscp << 2;
+		if (to_ai->ai_family == AF_INET) {
+			if (setsockopt(conn->conn_socket,
+			    IPPROTO_IP, IP_TOS,
+			    &tos, sizeof(tos)) == -1)
+				log_warn("setsockopt(IP_TOS) "
+				    "failed for %s",
+				    from_addr);
+		} else
+		if (to_ai->ai_family == AF_INET6) {
+			if (setsockopt(conn->conn_socket,
+			    IPPROTO_IPV6, IPV6_TCLASS,
+			    &tos, sizeof(tos)) == -1)
+				log_warn("setsockopt(IPV6_TCLASS) "
+				    "failed for %s",
+				    from_addr);
+		}
+	}
 	if (from_ai != NULL) {
 		error = bind(conn->conn_socket, from_ai->ai_addr,
 		    from_ai->ai_addrlen);