Date:   Thu,  4 Oct 2018 16:17:10 -0700
From:   Vinicius Costa Gomes <vinicius.gomes@...el.com>
To:     netdev@...r.kernel.org
Cc:     Vinicius Costa Gomes <vinicius.gomes@...el.com>, jhs@...atatu.com,
        xiyou.wangcong@...il.com, jiri@...nulli.us,
        jesus.sanchez-palencia@...el.com, ilias.apalodimas@...aro.org,
        simon.fok@...systems.com
Subject: [PATCH iproute2 net-next v2 5/6] tc: Add support for configuring the taprio scheduler

This traffic scheduler allows traffic classes states (transmission
allowed/not allowed, in the simplest case) to be scheduled, according
to a pre-generated time sequence. This is the basis of the IEEE
802.1Qbv specification.

Example configuration:

tc qdisc replace dev enp3s0 parent root handle 100 taprio \
          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 \
	  base-time 1528743495910289987 \
	  sched-entry S 01 300000 \
	  sched-entry S 02 300000 \
	  sched-entry S 04 300000 \
	  clockid CLOCK_TAI

The configuration format is similar to mqprio. The main difference is
the presence of a schedule, built by multiple "sched-entry"
definitions, each entry has the following format:

     sched-entry <CMD> <GATE MASK> <INTERVAL>

The only supported <CMD> is "S", which means "SetGateStates",
following the IEEE 802.1Qbv-2015 definition (Table 8-6). <GATE MASK>
is a bitmask where each bit is a associated with a traffic class, so
bit 0 (the least significant bit) being "on" means that traffic class
0 is "active" for that schedule entry. <INTERVAL> is a time duration
in nanoseconds that specifies for how long that state defined by <CMD>
and <GATE MASK> should be held before moving to the next entry.

This schedule is circular, that is, after the last entry is executed
it starts from the first one, indefinitely.

The other parameters can be defined as follows:

 - base-time: specifies the instant when the schedule starts, if
  'base-time' is a time in the past, the schedule will start at

 	      base-time + (N * cycle-time)

   where N is the smallest integer so the resulting time is greater
   than "now", and "cycle-time" is the sum of all the intervals of the
   entries in the schedule;

 - clockid: specifies the reference clock to be used;

The parameters should be similar to what the IEEE 802.1Q family of
specification defines.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>
Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@...el.com>
---
 tc/Makefile   |   1 +
 tc/q_taprio.c | 400 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 401 insertions(+)
 create mode 100644 tc/q_taprio.c

diff --git a/tc/Makefile b/tc/Makefile
index 5a1a7ff9..25a28284 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -74,6 +74,7 @@ TCMODULES += e_bpf.o
 TCMODULES += f_matchall.o
 TCMODULES += q_cbs.o
 TCMODULES += q_etf.o
+TCMODULES += q_taprio.o
 
 TCSO :=
 ifeq ($(TC_CONFIG_ATM),y)
diff --git a/tc/q_taprio.c b/tc/q_taprio.c
new file mode 100644
index 00000000..562dacb8
--- /dev/null
+++ b/tc/q_taprio.c
@@ -0,0 +1,400 @@
+/*
+ * q_taprio.c	Time Aware Priority Scheduler
+ *
+ *		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@...el.com>
+ * 		Jesus Sanchez-Palencia <jesus.sanchez-palencia@...el.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <syslog.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <string.h>
+
+#include "utils.h"
+#include "tc_util.h"
+#include "list.h"
+
+struct sched_entry {
+	struct list_head list;
+	uint32_t index;
+	uint32_t interval;
+	uint32_t gatemask;
+	uint8_t cmd;
+};
+
+#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: ... taprio clockid CLOCKID\n");
+	fprintf(stderr, "                  [num_tc NUMBER] [map P0 P1 ...] ");
+	fprintf(stderr, "                  [queues COUNT@...SET COUNT@...SET COUNT@...SET ...] ");
+	fprintf(stderr, "                  [ [sched-entry index cmd gate-mask interval] ... ] ");
+	fprintf(stderr, "                  [base-time time] ");
+	fprintf(stderr, "\nCLOCKID must be a valid SYS-V id (i.e. CLOCK_TAI)");
+	fprintf(stderr, "\n");
+}
+
+static void explain_clockid(const char *val)
+{
+	fprintf(stderr, "taprio: 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 const char *entry_cmd_to_str(__u8 cmd)
+{
+	switch (cmd) {
+	case TC_TAPRIO_CMD_SET_GATES:
+		return "S";
+	default:
+		return "Invalid";
+	}
+}
+
+static int str_to_entry_cmd(const char *str)
+{
+	if (strcmp(str, "S") == 0)
+		return TC_TAPRIO_CMD_SET_GATES;
+
+	return -1;
+}
+
+static int add_sched_list(struct list_head *sched_entries, struct nlmsghdr *n)
+{
+	struct sched_entry *e;
+
+	list_for_each_entry(e, sched_entries, list) {
+		struct rtattr *a;
+
+		a = addattr_nest(n, 1024, TCA_TAPRIO_SCHED_ENTRY);
+
+		addattr_l(n, 1024, TCA_TAPRIO_SCHED_ENTRY_CMD, &e->cmd, sizeof(e->cmd));
+		addattr_l(n, 1024, TCA_TAPRIO_SCHED_ENTRY_GATE_MASK, &e->gatemask, sizeof(e->gatemask));
+		addattr_l(n, 1024, TCA_TAPRIO_SCHED_ENTRY_INTERVAL, &e->interval, sizeof(e->interval));
+
+		addattr_nest_end(n, a);
+	}
+
+	return 0;
+}
+
+static void explain_sched_entry(void)
+{
+	fprintf(stderr, "Usage: ... taprio ... sched-entry <cmd> <gate mask> <interval>\n");
+}
+
+static struct sched_entry *create_entry(uint32_t gatemask, uint32_t interval, uint8_t cmd)
+{
+	struct sched_entry *e;
+
+	e = calloc(1, sizeof(*e));
+	if (!e)
+		return NULL;
+
+	e->gatemask = gatemask;
+	e->interval = interval;
+	e->cmd = cmd;
+
+	return e;
+}
+
+static int taprio_parse_opt(struct qdisc_util *qu, int argc,
+			    char **argv, struct nlmsghdr *n, const char *dev)
+{
+	__s32 clockid = CLOCKID_INVALID;
+	struct tc_mqprio_qopt opt = { };
+	struct list_head sched_entries;
+	struct rtattr *tail;
+	__s64 base_time = 0;
+	int err, idx;
+
+	INIT_LIST_HEAD(&sched_entries);
+
+	while (argc > 0) {
+		idx = 0;
+		if (strcmp(*argv, "num_tc") == 0) {
+			NEXT_ARG();
+			if (get_u8(&opt.num_tc, *argv, 10)) {
+				fprintf(stderr, "Illegal \"num_tc\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "map") == 0) {
+			while (idx < TC_QOPT_MAX_QUEUE && NEXT_ARG_OK()) {
+				NEXT_ARG();
+				if (get_u8(&opt.prio_tc_map[idx], *argv, 10)) {
+					PREV_ARG();
+					break;
+				}
+				idx++;
+			}
+			for ( ; idx < TC_QOPT_MAX_QUEUE; idx++)
+				opt.prio_tc_map[idx] = 0;
+		} else if (strcmp(*argv, "queues") == 0) {
+			char *tmp, *tok;
+
+			while (idx < TC_QOPT_MAX_QUEUE && NEXT_ARG_OK()) {
+				NEXT_ARG();
+
+				tmp = strdup(*argv);
+				if (!tmp)
+					break;
+
+				tok = strtok(tmp, "@");
+				if (get_u16(&opt.count[idx], tok, 10)) {
+					free(tmp);
+					PREV_ARG();
+					break;
+				}
+				tok = strtok(NULL, "@");
+				if (get_u16(&opt.offset[idx], tok, 10)) {
+					free(tmp);
+					PREV_ARG();
+					break;
+				}
+				free(tmp);
+				idx++;
+			}
+		} else if (strcmp(*argv, "sched-entry") == 0) {
+			uint32_t mask, interval;
+			struct sched_entry *e;
+			uint8_t cmd;
+
+			NEXT_ARG();
+			err = str_to_entry_cmd(*argv);
+			if (err < 0) {
+				explain_sched_entry();
+				return  -1;
+			}
+			cmd = err;
+
+			NEXT_ARG();
+			if (get_u32(&mask, *argv, 16)) {
+				explain_sched_entry();
+				return -1;
+			}
+
+			NEXT_ARG();
+			if (get_u32(&interval, *argv, 0)) {
+				explain_sched_entry();
+				return -1;
+			}
+
+			e = create_entry(mask, interval, cmd);
+			if (!e) {
+				fprintf(stderr, "taprio: not enough memory for new schedule entry\n");
+				return -1;
+			}
+
+			list_add_tail(&e->list, &sched_entries);
+
+		} else if (strcmp(*argv, "base-time") == 0) {
+			NEXT_ARG();
+			if (get_s64(&base_time, *argv, 10)) {
+				PREV_ARG();
+				break;
+			}
+		} else if (strcmp(*argv, "clockid") == 0) {
+			NEXT_ARG();
+			if (clockid != CLOCKID_INVALID) {
+				fprintf(stderr, "taprio: duplicate \"clockid\" specification\n");
+				return -1;
+			}
+			if (get_clockid(&clockid, *argv)) {
+				explain_clockid(*argv);
+				return -1;
+			}
+		} else if (strcmp(*argv, "help") == 0) {
+			explain();
+			return -1;
+		} else {
+			fprintf(stderr, "Unknown argument\n");
+			return -1;
+		}
+		argc--; argv++;
+	}
+
+	tail = NLMSG_TAIL(n);
+	addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
+
+	if (opt.num_tc > 0)
+		addattr_l(n, 1024, TCA_TAPRIO_ATTR_PRIOMAP, &opt, sizeof(opt));
+
+	if (base_time)
+		addattr_l(n, 1024, TCA_TAPRIO_ATTR_SCHED_BASE_TIME, &base_time, sizeof(base_time));
+
+	addattr_l(n, 1024, TCA_TAPRIO_ATTR_SCHED_CLOCKID, &clockid, sizeof(clockid));
+
+	if (!list_empty(&sched_entries)) {
+		struct rtattr *entry_list;
+		entry_list = addattr_nest(n, 1024, TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST | NLA_F_NESTED);
+
+		err = add_sched_list(&sched_entries, n);
+		if (err < 0) {
+			fprintf(stderr, "Could not add schedule to netlink message\n");
+			return -1;
+		}
+
+		addattr_nest_end(n, entry_list);
+	}
+
+	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+
+	return 0;
+}
+
+static int print_sched_list(FILE *f, struct rtattr *list)
+{
+	struct rtattr *item;
+	int rem;
+
+	if (list == NULL)
+		return 0;
+
+	rem = RTA_PAYLOAD(list);
+
+	open_json_array(PRINT_JSON, "schedule");
+
+	for (item = RTA_DATA(list); RTA_OK(item, rem); item = RTA_NEXT(item, rem)) {
+		struct rtattr *tb[TCA_TAPRIO_SCHED_ENTRY_MAX + 1];
+		__u32 index = 0, gatemask = 0, interval = 0;
+		__u8 command = 0;
+
+		parse_rtattr_nested(tb, TCA_TAPRIO_SCHED_ENTRY_MAX, item);
+
+		if (tb[TCA_TAPRIO_SCHED_ENTRY_INDEX])
+			index = rta_getattr_u32(tb[TCA_TAPRIO_SCHED_ENTRY_INDEX]);
+
+		if (tb[TCA_TAPRIO_SCHED_ENTRY_CMD])
+			command = rta_getattr_u8(tb[TCA_TAPRIO_SCHED_ENTRY_CMD]);
+
+		if (tb[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK])
+			gatemask = rta_getattr_u32(tb[TCA_TAPRIO_SCHED_ENTRY_GATE_MASK]);
+
+		if (tb[TCA_TAPRIO_SCHED_ENTRY_INTERVAL])
+			interval = rta_getattr_u32(tb[TCA_TAPRIO_SCHED_ENTRY_INTERVAL]);
+
+		open_json_object(NULL);
+		print_uint(PRINT_ANY, "index", "\tindex %u", index);
+		print_string(PRINT_ANY, "cmd", " cmd %s", entry_cmd_to_str(command));
+		print_0xhex(PRINT_ANY, "gatemask", " gatemask %#x", gatemask);
+		print_uint(PRINT_ANY, "interval", " interval %u", interval);
+		close_json_object();
+
+		print_string(PRINT_FP, NULL, "%s", _SL_);
+	}
+
+	close_json_array(PRINT_ANY, "");
+
+	return 0;
+}
+
+static int taprio_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	struct rtattr *tb[TCA_TAPRIO_ATTR_MAX + 1];
+	struct tc_mqprio_qopt *qopt = 0;
+	__s32 clockid = CLOCKID_INVALID;
+	__s64 base_time = 0;
+	int i;
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_TAPRIO_ATTR_MAX, opt);
+
+	if (tb[TCA_TAPRIO_ATTR_PRIOMAP] == NULL)
+		return -1;
+
+	qopt = RTA_DATA(tb[TCA_TAPRIO_ATTR_PRIOMAP]);
+
+	print_uint(PRINT_ANY, "tc", "tc %u ", qopt->num_tc);
+
+	open_json_array(PRINT_ANY, "map");
+	for (i = 0; i <= TC_PRIO_MAX; i++)
+		print_uint(PRINT_ANY, NULL, " %u", qopt->prio_tc_map[i]);
+	close_json_array(PRINT_ANY, "");
+
+	print_string(PRINT_FP, NULL, "%s", _SL_);
+
+	open_json_array(PRINT_ANY, "queues");
+	for (i = 0; i < qopt->num_tc; i++) {
+		open_json_object(NULL);
+		print_uint(PRINT_ANY, "offset", " offset %u", qopt->offset[i]);
+		print_uint(PRINT_ANY, "count", " count %u", qopt->count[i]);
+		close_json_object();
+	}
+	close_json_array(PRINT_ANY, "");
+
+	print_string(PRINT_FP, NULL, "%s", _SL_);
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_BASE_TIME])
+		base_time = rta_getattr_s64(tb[TCA_TAPRIO_ATTR_SCHED_BASE_TIME]);
+
+	if (tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID])
+		clockid = rta_getattr_s32(tb[TCA_TAPRIO_ATTR_SCHED_CLOCKID]);
+
+	print_string(PRINT_ANY, "clockid", "clockid %s", get_clock_name(clockid));
+
+	print_lluint(PRINT_ANY, "base_time", " base-time %lld", base_time);
+
+	print_string(PRINT_FP, NULL, "%s", _SL_);
+
+	return print_sched_list(f, tb[TCA_TAPRIO_ATTR_SCHED_ENTRY_LIST]);
+}
+
+struct qdisc_util taprio_qdisc_util = {
+	.id		= "taprio",
+	.parse_qopt	= taprio_parse_opt,
+	.print_qopt	= taprio_print_opt,
+};
-- 
2.19.0

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