From 4dfbcffbb90621d2cdc3ce15fd8709837d927aaf Mon Sep 17 00:00:00 2001
From: Richard Scheffenegger <rscheff@FreeBSD.org>
Date: Sat, 24 Oct 2020 21:07:13 +0000
Subject: Add network QoS support for PCP to iscsi initiator.

Make the Ethernet PCP codepoint configurable
for L2 local traffic, to allow lower latency for
iSCSI block IO. This addresses the initiator
side only.

Reviewed by:	mav, trasz, bcr
Sponsored by:	NetApp, Inc.
Differential Revision:	https://reviews.freebsd.org/D26739
---
 usr.bin/iscsictl/iscsi.conf.5 |  7 +++++++
 usr.bin/iscsictl/iscsictl.c   |  5 +++++
 usr.bin/iscsictl/iscsictl.h   |  1 +
 usr.bin/iscsictl/parse.y      | 25 +++++++++++++++++++++++++
 usr.bin/iscsictl/token.l      |  1 +
 5 files changed, 39 insertions(+)

(limited to 'usr.bin')

diff --git a/usr.bin/iscsictl/iscsi.conf.5 b/usr.bin/iscsictl/iscsi.conf.5
index f8b4bca4a4c9c..8b2c08cb47a00 100644
--- a/usr.bin/iscsictl/iscsi.conf.5
+++ b/usr.bin/iscsictl/iscsi.conf.5
@@ -155,6 +155,13 @@ and
 codepoints.
 Default is no specified dscp codepoint, which means the default
 of the outgoing interface is used.
+.It Cm pcp
+The 802.1Q Priority CodePoint used for sending packets.
+The PCP can be set to a value in the range between
+.Qq Ar 0
+to
+.Qq Ar 7 .
+When omitted, the default for the outgoing interface is used.
 .El
 .Sh FILES
 .Bl -tag -width indent
diff --git a/usr.bin/iscsictl/iscsictl.c b/usr.bin/iscsictl/iscsictl.c
index fa5754d3581f1..de7725401dcfc 100644
--- a/usr.bin/iscsictl/iscsictl.c
+++ b/usr.bin/iscsictl/iscsictl.c
@@ -88,6 +88,7 @@ target_new(struct conf *conf)
 		xo_err(1, "calloc");
 	targ->t_conf = conf;
 	targ->t_dscp = -1;
+	targ->t_pcp = -1;
 	TAILQ_INSERT_TAIL(&conf->conf_targets, targ, t_next);
 
 	return (targ);
@@ -360,6 +361,7 @@ conf_from_target(struct iscsi_session_conf *conf,
 	else
 		conf->isc_data_digest = ISCSI_DIGEST_NONE;
 	conf->isc_dscp = targ->t_dscp;
+	conf->isc_pcp = targ->t_pcp;
 }
 
 static int
@@ -540,6 +542,9 @@ kernel_list(int iscsi_fd, const struct target *targ __unused,
 			if (conf->isc_dscp != -1)
 				xo_emit("{L:/%-26s}{V:dscp/0x%02x}\n",
 				    "Target DSCP:", conf->isc_dscp);
+			if (conf->isc_pcp != -1)
+				xo_emit("{L:/%-26s}{V:pcp/0x%02x}\n",
+				    "Target PCP:", conf->isc_pcp);
 			xo_close_container("target");
 
 			xo_open_container("auth");
diff --git a/usr.bin/iscsictl/iscsictl.h b/usr.bin/iscsictl/iscsictl.h
index d5e2fd25c218c..9718581c06d65 100644
--- a/usr.bin/iscsictl/iscsictl.h
+++ b/usr.bin/iscsictl/iscsictl.h
@@ -79,6 +79,7 @@ struct target {
 	int			t_enable;
 	int			t_protocol;
 	int			t_dscp;
+	int			t_pcp;
 	char			*t_offload;
 	char			*t_user;
 	char			*t_secret;
diff --git a/usr.bin/iscsictl/parse.y b/usr.bin/iscsictl/parse.y
index 9e4a28b50fed2..e28c8e82a115c 100644
--- a/usr.bin/iscsictl/parse.y
+++ b/usr.bin/iscsictl/parse.y
@@ -133,6 +133,8 @@ target_entry:
 	ignored
 	|
 	dscp
+	|
+	pcp
 	;
 
 target_name:	TARGET_NAME EQUALS STR
@@ -306,6 +308,8 @@ dscp:		DSCP EQUALS STR
 	{
 		uint64_t tmp;
 
+		if (target->t_dscp != -1)
+			xo_errx(1, "duplicated dscp at line %d", lineno);
 		if (strcmp($3, "0x") == 0) {
 			tmp = strtol($3 + 2, NULL, 16);
 		} else if (expand_number($3, &tmp) != 0) {
@@ -344,6 +348,27 @@ dscp:		DSCP EQUALS STR
 	| DSCP EQUALS AF43	{ target->t_dscp = IPTOS_DSCP_AF43 >> 2 ; }
 	;
 
+pcp:	PCP EQUALS STR
+	{
+		uint64_t tmp;
+
+		if (target->t_pcp != -1)
+			xo_errx(1, "duplicated pcp at line %d", lineno);
+
+		if (expand_number($3, &tmp) != 0) {
+			yyerror("invalid numeric value");
+			free($3);
+			return(1);
+		}
+		if (!((tmp >=0) && (tmp <= 7))) {
+			yyerror("invalid pcp value");
+			return(1);
+		}
+
+		target->t_pcp = tmp;
+	}
+	;
+
 %%
 
 void
diff --git a/usr.bin/iscsictl/token.l b/usr.bin/iscsictl/token.l
index 9f6a0d707fb0d..d3e5f25d21c14 100644
--- a/usr.bin/iscsictl/token.l
+++ b/usr.bin/iscsictl/token.l
@@ -69,6 +69,7 @@ protocol		{ return PROTOCOL; }
 offload			{ return OFFLOAD; }
 port			{ return IGNORED; }
 dscp			{ return DSCP; }
+pcp			{ return PCP; }
 MaxConnections		{ return IGNORED; }
 TargetAlias		{ return IGNORED; }
 TargetPortalGroupTag	{ return IGNORED; }
-- 
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