[PATCH v4 iproute2-next 2/3] tc: Add support for the ETF Qdisc

[Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>]

From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

The "Earliest TxTime First" (ETF) queueing discipline allows precise
control of the transmission time of packets by providing a sorted
time-based scheduling of packets.

The syntax is:

tc qdisc add dev DEV parent NODE etf delta <DELTA>
                     clockid <CLOCKID> [offload] [deadline_mode]

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
---
 tc/Makefile |   1 +
 tc/q_etf.c  | 181 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 182 insertions(+)
 create mode 100644 tc/q_etf.c

diff --git a/tc/Makefile b/tc/Makefile
index dfd00267..4525c0fb 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -71,6 +71,7 @@ TCMODULES += q_clsact.o
 TCMODULES += e_bpf.o
 TCMODULES += f_matchall.o
 TCMODULES += q_cbs.o
+TCMODULES += q_etf.o
 
 TCSO :=
 ifeq ($(TC_CONFIG_ATM),y)
diff --git a/tc/q_etf.c b/tc/q_etf.c
new file mode 100644
index 00000000..79a06ba8
--- /dev/null
+++ b/tc/q_etf.c
@@ -0,0 +1,181 @@
+/*
+ * q_etf.c		Earliest TxTime First (ETF).
+ *
+ *		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>
+ *		Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tc_util.h"
+
+#define CLOCKID_INVALID (-1)
+static const struct static_clockid {
+	const char *name;
+	clockid_t clockid;
+} clockids_sysv[] = {
+	{ "REALTIME", CLOCK_REALTIME },
+	{ "TAI", CLOCK_TAI },
+	{ "BOOTTIME", CLOCK_BOOTTIME },
+	{ "MONOTONIC", CLOCK_MONOTONIC },
+	{ NULL }
+};
+
+static void explain(void)
+{
+	fprintf(stderr, "Usage: ... etf delta NANOS clockid CLOCKID [offload] [deadline_mode]\n");
+	fprintf(stderr, "CLOCKID must be a valid SYS-V id (i.e. CLOCK_TAI)\n");
+}
+
+static void explain1(const char *arg, const char *val)
+{
+	fprintf(stderr, "etf: illegal value for \"%s\": \"%s\"\n", arg, val);
+}
+
+static void explain_clockid(const char *val)
+{
+	fprintf(stderr, "etf: illegal value for \"clockid\": \"%s\".\n", val);
+	fprintf(stderr, "It must be a valid SYS-V id (i.e. CLOCK_TAI)\n");
+}
+
+static int get_clockid(__s32 *val, const char *arg)
+{
+	const struct static_clockid *c;
+
+	/* Drop the CLOCK_ prefix if that is being used. */
+	if (strcasestr(arg, "CLOCK_") != NULL)
+		arg += sizeof("CLOCK_") - 1;
+
+	for (c = clockids_sysv; c->name; c++) {
+		if (strcasecmp(c->name, arg) == 0) {
+			*val = c->clockid;
+
+			return 0;
+		}
+	}
+
+	return -1;
+}
+
+static const char* get_clock_name(clockid_t clockid)
+{
+	const struct static_clockid *c;
+
+	for (c = clockids_sysv; c->name; c++) {
+		if (clockid == c->clockid)
+			return c->name;
+	}
+
+	return "invalid";
+}
+
+static int etf_parse_opt(struct qdisc_util *qu, int argc,
+			 char **argv, struct nlmsghdr *n, const char *dev)
+{
+	struct tc_etf_qopt opt = {
+		.clockid = CLOCKID_INVALID,
+	};
+	struct rtattr *tail;
+
+	while (argc > 0) {
+		if (matches(*argv, "offload") == 0) {
+			if (opt.flags & TC_ETF_OFFLOAD_ON) {
+				fprintf(stderr, "etf: duplicate \"offload\" specification\n");
+				return -1;
+			}
+
+			opt.flags |= TC_ETF_OFFLOAD_ON;
+		} else if (matches(*argv, "deadline_mode") == 0) {
+			if (opt.flags & TC_ETF_DEADLINE_MODE_ON) {
+				fprintf(stderr, "etf: duplicate \"deadline_mode\" specification\n");
+				return -1;
+			}
+
+			opt.flags |= TC_ETF_DEADLINE_MODE_ON;
+		} else if (matches(*argv, "delta") == 0) {
+			NEXT_ARG();
+			if (opt.delta) {
+				fprintf(stderr, "etf: duplicate \"delta\" specification\n");
+				return -1;
+			}
+			if (get_s32(&opt.delta, *argv, 0)) {
+				explain1("delta", *argv);
+				return -1;
+			}
+		} else if (matches(*argv, "clockid") == 0) {
+			NEXT_ARG();
+			if (opt.clockid != CLOCKID_INVALID) {
+				fprintf(stderr, "etf: duplicate \"clockid\" specification\n");
+				return -1;
+			}
+			if (get_clockid(&opt.clockid, *argv)) {
+				explain_clockid(*argv);
+				return -1;
+			}
+		} else if (strcmp(*argv, "help") == 0) {
+			explain();
+			return -1;
+		} else {
+			fprintf(stderr, "etf: 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_ETF_PARMS, &opt, sizeof(opt));
+	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+	return 0;
+}
+
+static int etf_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	struct rtattr *tb[TCA_ETF_MAX+1];
+	struct tc_etf_qopt *qopt;
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_ETF_MAX, opt);
+
+	if (tb[TCA_ETF_PARMS] == NULL)
+		return -1;
+
+	qopt = RTA_DATA(tb[TCA_ETF_PARMS]);
+	if (RTA_PAYLOAD(tb[TCA_ETF_PARMS])  < sizeof(*qopt))
+		return -1;
+
+	print_string(PRINT_ANY, "clockid", "clockid %s ",
+		     get_clock_name(qopt->clockid));
+
+	print_uint(PRINT_ANY, "delta", "delta %d ", qopt->delta);
+	print_string(PRINT_ANY, "offload", "offload %s ",
+				(qopt->flags & TC_ETF_OFFLOAD_ON) ? "on" : "off");
+	print_string(PRINT_ANY, "deadline_mode", "deadline_mode %s",
+				(qopt->flags & TC_ETF_DEADLINE_MODE_ON) ? "on" : "off");
+
+	return 0;
+}
+
+struct qdisc_util etf_qdisc_util = {
+	.id		= "etf",
+	.parse_qopt	= etf_parse_opt,
+	.print_qopt	= etf_print_opt,
+};
-- 
2.18.0