[iproute2 net-next v2 1/3] update headers with CBS API [ONLY FOR TESTING]

[iproute2 net-next v2 1/3] update headers with CBS API [ONLY FOR TESTING]

[Vinicius Costa Gomes]

The headers will be updated when iproute2 fetches the headers from
net-next, this patch is only to ease testing.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 include/linux/pkt_sched.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index 099bf552..41e349df 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -871,4 +871,22 @@ struct tc_pie_xstats {
 	__u32 maxq;             /* maximum queue size */
 	__u32 ecn_mark;         /* packets marked with ecn*/
 };
+
+/* CBS */
+struct tc_cbs_qopt {
+	__u8 offload;
+	__s32 hicredit;
+	__s32 locredit;
+	__s32 idleslope;
+	__s32 sendslope;
+};
+
+enum {
+	TCA_CBS_UNSPEC,
+	TCA_CBS_PARMS,
+	__TCA_CBS_MAX,
+};
+
+#define TCA_CBS_MAX (__TCA_CBS_MAX - 1)
+
 #endif
-- 
2.14.2

[iproute2 net-next v2 2/3] tc: Add support for the CBS qdisc

[Vinicius Costa Gomes]

The Credit Based Shaper (CBS) queueing discipline allows bandwidth
reservation with sub-milisecond precision. It is defined by the
802.1Q-2014 specification (section 8.6.8.2 and Annex L).

The syntax is:

tc qdisc add dev DEV parent NODE cbs locredit <LOCREDIT>
   		hicredit <HICREDIT> sendslope <SENDSLOPE>
		idleslope <IDLESLOPE>

(The order is not important)

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 tc/Makefile |   1 +
 tc/q_cbs.c  | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 143 insertions(+)
 create mode 100644 tc/q_cbs.c

diff --git a/tc/Makefile b/tc/Makefile
index 777de5e6..24bd3e2e 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -69,6 +69,7 @@ TCMODULES += q_hhf.o
 TCMODULES += q_clsact.o
 TCMODULES += e_bpf.o
 TCMODULES += f_matchall.o
+TCMODULES += q_cbs.o
 
 TCSO :=
 ifeq ($(TC_CONFIG_ATM),y)
diff --git a/tc/q_cbs.c b/tc/q_cbs.c
new file mode 100644
index 00000000..e53be654
--- /dev/null
+++ b/tc/q_cbs.c
@@ -0,0 +1,142 @@
+/*
+ * q_cbs.c		CBS.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Vinicius Costa Gomes <vinicius.gomes@intel.com>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tc_util.h"
+
+static void explain(void)
+{
+	fprintf(stderr, "Usage: ... cbs hicredit BYTES locredit BYTES sendslope BPS idleslope BPS\n");
+	fprintf(stderr, "           [offload 0|1]\n");
+
+}
+
+static void explain1(const char *arg, const char *val)
+{
+	fprintf(stderr, "cbs: illegal value for \"%s\": \"%s\"\n", arg, val);
+}
+
+static int cbs_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+{
+	struct tc_cbs_qopt opt = {};
+	struct rtattr *tail;
+
+	while (argc > 0) {
+		if (matches(*argv, "offload") == 0) {
+			NEXT_ARG();
+			if (opt.offload) {
+				fprintf(stderr, "cbs: duplicate \"offload\" specification\n");
+				return -1;
+			}
+			if (get_u8(&opt.offload, *argv, 0)) {
+				explain1("offload", *argv);
+				return -1;
+			}
+		} else if (matches(*argv, "hicredit") == 0) {
+			NEXT_ARG();
+			if (opt.hicredit) {
+				fprintf(stderr, "cbs: duplicate \"hicredit\" specification\n");
+				return -1;
+			}
+			if (get_s32(&opt.hicredit, *argv, 0)) {
+				explain1("hicredit", *argv);
+				return -1;
+			}
+		} else if (matches(*argv, "locredit") == 0) {
+			NEXT_ARG();
+			if (opt.locredit) {
+				fprintf(stderr, "cbs: duplicate \"locredit\" specification\n");
+				return -1;
+			}
+			if (get_s32(&opt.locredit, *argv, 0)) {
+				explain1("locredit", *argv);
+				return -1;
+			}
+		} else if (matches(*argv, "sendslope") == 0) {
+			NEXT_ARG();
+			if (opt.sendslope) {
+				fprintf(stderr, "cbs: duplicate \"sendslope\" specification\n");
+				return -1;
+			}
+			if (get_s32(&opt.sendslope, *argv, 0)) {
+				explain1("sendslope", *argv);
+				return -1;
+			}
+		} else if (matches(*argv, "idleslope") == 0) {
+			NEXT_ARG();
+			if (opt.idleslope) {
+				fprintf(stderr, "cbs: duplicate \"idleslope\" specification\n");
+				return -1;
+			}
+			if (get_s32(&opt.idleslope, *argv, 0)) {
+				explain1("idleslope", *argv);
+				return -1;
+			}
+		} else if (strcmp(*argv, "help") == 0) {
+			explain();
+			return -1;
+		} else {
+			fprintf(stderr, "cbs: unknown parameter \"%s\"\n", *argv);
+			explain();
+			return -1;
+		}
+		argc--; argv++;
+	}
+
+	tail = NLMSG_TAIL(n);
+	addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
+	addattr_l(n, 2024, TCA_CBS_PARMS, &opt, sizeof(opt));
+	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+	return 0;
+}
+
+static int cbs_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	struct rtattr *tb[TCA_CBS_MAX+1];
+	struct tc_cbs_qopt *qopt;
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_CBS_MAX, opt);
+
+	if (tb[TCA_CBS_PARMS] == NULL)
+		return -1;
+
+	qopt = RTA_DATA(tb[TCA_CBS_PARMS]);
+	if (RTA_PAYLOAD(tb[TCA_CBS_PARMS])  < sizeof(*qopt))
+		return -1;
+
+	fprintf(f, "hicredit %d ", qopt->hicredit);
+	fprintf(f, "locredit %d ", qopt->locredit);
+	fprintf(f, "sendslope %d ", qopt->sendslope);
+	fprintf(f, "idleslope %d ", qopt->idleslope);
+	fprintf(f, "offload %d ", qopt->offload);
+
+	return 0;
+}
+
+struct qdisc_util cbs_qdisc_util = {
+	.id		= "cbs",
+	.parse_qopt	= cbs_parse_opt,
+	.print_qopt	= cbs_print_opt,
+};
-- 
2.14.2

[iproute2 net-next v2 3/3] man: Add initial manpage for tc-cbs(8)

[Vinicius Costa Gomes]

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
---
 man/man8/tc-cbs.8 | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 man/man8/tc-cbs.8

diff --git a/man/man8/tc-cbs.8 b/man/man8/tc-cbs.8
new file mode 100644
index 00000000..97e00c84
--- /dev/null
+++ b/man/man8/tc-cbs.8
@@ -0,0 +1,112 @@
+.TH CBS 8 "18 Sept 2017" "iproute2" "Linux"
+.SH NAME
+CBS \- Credit Based Shaper (CBS) Qdisc
+.SH SYNOPSIS
+.B tc qdisc ... dev
+dev
+.B parent
+classid
+.B [ handle
+major:
+.B ] cbs idleslope
+idleslope
+.B sendslope
+sendslope
+.B hicredit
+hicredit
+.B locredit
+locredit
+.B [ offload
+0|1
+.B ]
+
+.SH DESCRIPTION
+The CBS (Credit Based Shaper) qdisc implements the shaping algorithm
+defined by the IEEE 802.1Q-2014 Section 8.6.8.2, which applies a well
+defined rate limiting method to the traffic.
+
+This queueing discipline is intended to be used by TSN (Time Sensitive
+Networking) applications, the CBS parameters are derived directly by
+what is described by the Annex L of the IEEE 802.1Q-2014
+Sepcification. The algorithm and how it affects the latency are
+detailed there.
+
+CBS is meant to be installed under another qdisc that maps packet
+flows to traffic classes, one example is
+.BR mqprio(8).
+
+.SH PARAMETERS
+.TP
+idleslope
+Idleslope is the rate of credits that is accumulated (in kilobits per
+second) when there is at least one packet waiting for transmission.
+Packets are transmitted when the current value of credits is equal or
+greater than zero. When there is no packet to be transmitted the
+amount of credits is set to zero. This is the main tunable of the CBS
+algorithm.
+.TP
+sendslope
+Sendslope is the rate of credits that is depleted (it should be a
+negative number of kilobits per second) when a transmission is
+ocurring. It can be calculated as follows, (IEEE 802.1Q-2014 Section
+8.6.8.2 item g):
+
+sendslope = idleslope - port_transmit_rate
+
+.TP
+hicredit
+Hicredit defines the maximum amount of credits (in bytes) that can be
+accumulated. Hicredit depends on the characteristics of interfering
+traffic, 'max_interference_size' is the maximum size of any burst of
+traffic that can delay the transmission of a frame that is available
+for transmission for this traffic class, (IEEE 802.1Q-2014 Annex L,
+Equation L-3):
+
+hicredit = max_interference_size * (idleslope / port_transmit_rate)
+
+.TP
+locredit
+Locredit is the minimum amount of credits that can be reached. It is a
+function of the traffic flowing through this qdisc (IEEE 802.1Q-2014
+Annex L, Equation L-2):
+
+locredit = max_frame_size * (sendslope / port_transmit_rate)
+
+.TP
+offload
+When
+.B offload
+is 1,
+.BR cbs(8)
+will try to configure the network interface so the CBS algorithm runs
+in the controller. The default is 0.
+
+.SH EXAMPLES
+
+CBS is used to enforce a Quality of Service by limiting the data rate
+of a traffic class, to separate packets into traffic classes the user
+may choose
+.BR mqprio(8),
+and configure it like this:
+
+.EX
+# tc qdisc add dev eth0 handle 100: parent root mqprio num_tc 3 \\
+	map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \\
+	queues 1@0 1@1 2@2 \\
+	hw 0
+.EE
+.P
+To replace the current queuing disciple by CBS in the current queueing
+discipline connected to traffic class number 0, issue:
+.P
+.EX
+# tc qdisc replace dev eth0 parent 100:4 cbs \\
+	locredit -1470 hicredit 30 sendslope -980000 idleslope 20000
+.EE
+
+These values are obtained from the following parameters, idleslope is
+20mbit/s, the transmission rate is 1Gbit/s and the maximum interfering
+frame size is 1500 bytes.
+
+.SH AUTHORS
+Vinicius Costa Gomes <vinicius.gomes@intel.com>
-- 
2.14.2