[PATCH 2/2] iproute2: sch_rr support in tc

[PJ Waskiewicz <peter.p.waskiewicz.jr@intel.com>]

This patch applies on top of Patrick McHardy's RTNETLINK
patches to add nested compat attributes.  This is needed to maintain
ABI for sch_{rr|prio} in the kernel with respect to tc.  A new option,
namely multiqueue, was added to sch_prio and sch_rr.  This will allow
a user to turn multiqueue support on for sch_prio or sch_rr at loadtime.
Also, tc qdisc ls will display whether or not multiqueue is enabled on
that qdisc.  When in multiqueue mode, a user can specify a value of 0 for
bands, and the number of bands will be created to match the number of
queues on the device.

This patch is to support the new sch_rr (round-robin) qdisc being proposed
in NET for multiqueue network device support in the Linux network stack.
It uses q_prio.c as the template, since the qdiscs are nearly identical,
outside of the ->dequeue() routine.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
---

 include/linux/pkt_sched.h |    9 +++
 tc/q_prio.c               |   24 +++++++--
 tc/q_rr.c                 |  127 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 155 insertions(+), 5 deletions(-)

diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index d10f353..4f1531b 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -101,6 +101,15 @@ struct tc_prio_qopt
 	__u8	priomap[TC_PRIO_MAX+1];	/* Map: logical priority -> PRIO band */
 };
 
+enum
+{
+        TCA_PRIO_UNSPEC,
+        TCA_PRIO_MQ,
+        __TCA_PRIO_MAX
+};
+
+#define TCA_PRIO_MAX    (__TCA_PRIO_MAX - 1)
+
 /* TBF section */
 
 struct tc_tbf_qopt
diff --git a/tc/q_prio.c b/tc/q_prio.c
index d696e1b..6883edb 100644
--- a/tc/q_prio.c
+++ b/tc/q_prio.c
@@ -29,7 +29,7 @@
 
 static void explain(void)
 {
-	fprintf(stderr, "Usage: ... prio bands NUMBER priomap P1 P2...\n");
+	fprintf(stderr, "Usage: ... prio bands NUMBER priomap P1 P2...[multiqueue]\n");
 }
 
 #define usage() return(-1)
@@ -40,6 +40,8 @@ static int prio_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct n
 	int pmap_mode = 0;
 	int idx = 0;
 	struct tc_prio_qopt opt={3,{ 1, 2, 2, 2, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1 }};
+	struct rtattr *nest;
+	unsigned char mq = 0;
 
 	while (argc > 0) {
 		if (strcmp(*argv, "bands") == 0) {
@@ -57,6 +59,8 @@ static int prio_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct n
 				return -1;
 			}
 			pmap_mode = 1;
+		} else if (strcmp(*argv, "multiqueue") == 0) {
+			mq = 1;
 		} else if (strcmp(*argv, "help") == 0) {
 			explain();
 			return -1;
@@ -90,7 +94,10 @@ static int prio_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct n
 			opt.priomap[idx] = opt.priomap[TC_PRIO_BESTEFFORT];
 	}
 */
-	addattr_l(n, 1024, TCA_OPTIONS, &opt, sizeof(opt));
+	nest = addattr_nest_compat(n, 1024, TCA_OPTIONS, &opt, sizeof(opt));
+	if (mq)
+		addattr_l(n, 1024, TCA_PRIO_MQ, NULL, 0);
+	addattr_nest_compat_end(n, nest);
 	return 0;
 }
 
@@ -98,16 +105,23 @@ int prio_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
 {
 	int i;
 	struct tc_prio_qopt *qopt;
+	struct rtattr *tb[TCA_PRIO_MAX+1];
 
 	if (opt == NULL)
 		return 0;
 
-	if (RTA_PAYLOAD(opt)  < sizeof(*qopt))
-		return -1;
-	qopt = RTA_DATA(opt);
+	if (parse_rtattr_nested_compat(tb, TCA_PRIO_MAX, opt, qopt,
+					sizeof(*qopt)))
+                return -1;
+
 	fprintf(f, "bands %u priomap ", qopt->bands);
 	for (i=0; i<=TC_PRIO_MAX; i++)
 		fprintf(f, " %d", qopt->priomap[i]);
+
+	if (tb[TCA_PRIO_MQ])
+		fprintf(f, " multiqueue: %s ",
+		    *(unsigned char *)RTA_DATA(tb[TCA_PRIO_MQ]) ? "on" : "off");
+
 	return 0;
 }
 
diff --git a/tc/q_rr.c b/tc/q_rr.c
new file mode 100644
index 0000000..9335c47
--- /dev/null
+++ b/tc/q_rr.c
@@ -0,0 +1,127 @@
+/*
+ * q_rr.c		RR.
+ *
+ *		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:	PJ Waskiewicz, <peter.p.waskiewicz.jr@intel.com>
+ * Original Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> (from PRIO)
+ *
+ * Changes:
+ *
+ * Ole Husgaard <sparre@login.dknet.dk>: 990513: prio2band map was always reset.
+ * J Hadi Salim <hadi@cyberus.ca>: 990609: priomap fix.
+ */
+
+#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: ... rr bands NUMBER priomap P1 P2... [multiqueue]\n");
+}
+
+#define usage() return(-1)
+
+static int rr_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
+{
+	int ok = 0;
+	int pmap_mode = 0;
+	int idx = 0;
+	struct tc_prio_qopt opt={3,{ 1, 2, 2, 2, 1, 2, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1 }};
+	struct rtattr *nest;
+	unsigned char mq = 0;
+
+	while (argc > 0) {
+		if (strcmp(*argv, "bands") == 0) {
+			if (pmap_mode)
+				explain();
+			NEXT_ARG();
+			if (get_integer(&opt.bands, *argv, 10)) {
+				fprintf(stderr, "Illegal \"bands\"\n");
+				return -1;
+			}
+			ok++;
+		} else if (strcmp(*argv, "priomap") == 0) {
+			if (pmap_mode) {
+				fprintf(stderr, "Error: duplicate priomap\n");
+				return -1;
+			}
+			pmap_mode = 1;
+		} else if (strcmp(*argv, "help") == 0) {
+			explain();
+			return -1;
+		} else if (strcmp(*argv, "multiqueue") == 0) {
+			mq = 1;
+		} else {
+			unsigned band;
+			if (!pmap_mode) {
+				fprintf(stderr, "What is \"%s\"?\n", *argv);
+				explain();
+				return -1;
+			}
+			if (get_unsigned(&band, *argv, 10)) {
+				fprintf(stderr, "Illegal \"priomap\" element\n");
+				return -1;
+			}
+			if (band > opt.bands) {
+				fprintf(stderr, "\"priomap\" element is out of bands\n");
+				return -1;
+			}
+			if (idx > TC_PRIO_MAX) {
+				fprintf(stderr, "\"priomap\" index > TC_RR_MAX=%u\n", TC_PRIO_MAX);
+				return -1;
+			}
+			opt.priomap[idx++] = band;
+		}
+		argc--; argv++;
+	}
+
+	nest = addattr_nest_compat(n, 1024, TCA_OPTIONS, &opt, sizeof(opt));
+	if (mq)
+		addattr_l(n, 1024, TCA_PRIO_MQ, NULL, 0);
+	addattr_nest_compat_end(n, nest);
+	return 0;
+}
+
+int rr_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	int i;
+	struct tc_prio_qopt *qopt;
+	struct rtattr *tb[TCA_PRIO_MAX + 1];
+
+	if (opt == NULL)
+		return 0;
+
+	if (parse_rtattr_nested_compat(tb, TCA_PRIO_MAX, opt, qopt,
+						sizeof(*qopt)))
+		return -1;
+
+	fprintf(f, "bands %u priomap ", qopt->bands);
+	for (i=0; i <= TC_PRIO_MAX; i++)
+		fprintf(f, " %d", qopt->priomap[i]);
+
+	if (tb[TCA_PRIO_MQ])
+		fprintf(f, " multiqueue: %s ",
+		    *(unsigned char *)RTA_DATA(tb[TCA_PRIO_MQ]) ? "on" : "off");
+
+	return 0;
+}
+
+struct qdisc_util rr_qdisc_util = {
+	.id	 	= "rr",
+	.parse_qopt	= rr_parse_opt,
+	.print_qopt	= rr_print_opt,
+};