[Codel] [PATCH] iproute2: added preliminary codel support

["Dave Täht" <dave.taht@bufferbloat.net>]

this makes certain constants in the code variables, but
has seemingly good defaults.

target and interval can be specified with a ms, s, or us parameter
mtu is in bytes

ecn, while part of the api, is not enabled in the code
---
 include/linux/pkt_sched.h |   28 ++++++++++
 tc/Makefile               |    1 +
 tc/q_codel.c              |  135 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 tc/q_codel.c

diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h
index 410b33d..150aee9 100644
--- a/include/linux/pkt_sched.h
+++ b/include/linux/pkt_sched.h
@@ -654,4 +654,32 @@ struct tc_qfq_stats {
 	__u32 lmax;
 };
 
+/* CODEL */
+
+enum {
+	TCA_CODEL_UNSPEC,
+	TCA_CODEL_PARMS,
+	TCA_CODEL_TARGET,
+	TCA_CODEL_DEPTH,
+	TCA_CODEL_MINBYTES,
+	TCA_CODEL_INTERVAL,
+	__TCA_CODEL_MAX
+};
+
+#define TCA_CODEL_MAX	(__TCA_CODEL_MAX - 1)
+#define TC_CODEL_ECN 1
+
+struct tc_codel_qopt {
+        __u32 flags;	/* flags (e.g. ecn) */
+	__u32 target;	/* max delay, in us */
+        __u32 depth;	/* queue depth in packets */
+        __u32 minbytes;	/* MTU (usually) */
+        __u32 interval;	/* Sliding min time window width (us) */
+};
+
+struct tc_codel_stats {
+	__u64 drops;
+	__u64 marks;
+};
+
 #endif
diff --git a/tc/Makefile b/tc/Makefile
index be8cd5a..8a7cc8d 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -47,6 +47,7 @@ TCMODULES += em_cmp.o
 TCMODULES += em_u32.o
 TCMODULES += em_meta.o
 TCMODULES += q_mqprio.o
+TCMODULES += q_codel.o
 
 TCSO :=
 ifeq ($(TC_CONFIG_ATM),y)
diff --git a/tc/q_codel.c b/tc/q_codel.c
new file mode 100644
index 0000000..2ff51a1
--- /dev/null
+++ b/tc/q_codel.c
@@ -0,0 +1,135 @@
+/*
+ * q_codel.c	Controlled Delay
+ *
+ *		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:	Dave Taht <d@taht.net>
+ *
+ */
+
+
+
+#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: ... codel [target MAX_DELAY] [depth PACKETS]"
+                " [mtu MINBYTES]\n                 "
+		"[interval INTEGRATION_TIME] [ecn]\n" );
+}
+
+static int codel_parse_opt(struct qdisc_util *qu, int argc, char **argv,
+			 struct nlmsghdr *n)
+{
+	struct tc_codel_qopt opt;
+	struct rtattr *tail;
+
+	memset(&opt, 0, sizeof(opt));
+	opt.target = 5000;
+	opt.depth = 1000;
+	opt.interval = 1000*100;
+	opt.minbytes = 1500;
+	opt.flags = 0;
+
+	while (argc > 0) {
+	    if (strcmp(*argv, "target") == 0) {
+			NEXT_ARG();
+			if (get_time(&opt.target, *argv)) {
+				fprintf(stderr, "Illegal \"target\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "depth") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.depth, *argv, 0)) {
+				fprintf(stderr, "Illegal \"depth\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "interval") == 0) {
+			NEXT_ARG();
+			if (get_time(&opt.interval, *argv)) {
+				fprintf(stderr, "Illegal \"interval\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "mtu") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.minbytes, *argv, 0)) {
+				fprintf(stderr, "Illegal \"mtu\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "ecn") == 0) {
+			opt.flags |= TC_CODEL_ECN;
+		} else {
+			fprintf(stderr, "What is \"%s\"?\n", *argv);
+			explain();
+			return -1;
+		}
+		argc--; argv++;
+	}
+
+	tail = NLMSG_TAIL(n);
+	addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
+	addattr_l(n, 1024, TCA_CODEL_PARMS, &opt, sizeof(opt));
+	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+	return 0;
+}
+
+static int codel_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	struct rtattr *tb[__TCA_CODEL_MAX];
+	struct tc_codel_qopt *qopt;
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_CODEL_MAX, opt);
+	if (tb[TCA_CODEL_PARMS] == NULL)
+		return -1;
+	qopt = RTA_DATA(tb[TCA_CODEL_PARMS]);
+	if (RTA_PAYLOAD(tb[TCA_CODEL_PARMS]) < sizeof(*qopt))
+		return -1;
+	fprintf(f," target %dus depth %d mtu %d interval %dus %s\n",
+		qopt->target, qopt->depth, qopt->minbytes, 
+		qopt->interval, (qopt->flags & TC_CODEL_ECN) ? "ecn" : "");
+
+	return 0;
+}
+
+static int codel_print_xstats(struct qdisc_util *qu, FILE *f,
+			    struct rtattr *xstats)
+{
+    struct tc_codel_stats *st;
+
+    if (xstats == NULL)
+	    return 0;
+
+    if (RTA_PAYLOAD(xstats) < sizeof(*st))
+	    return -1;
+
+    st = RTA_DATA(xstats);
+    fprintf(f, "  dropped %lu marked %lu ",
+	    st->drops, st->marks);
+
+    return 0;
+}
+
+struct qdisc_util codel_qdisc_util = {
+	.id		= "codel",
+	.parse_qopt	= codel_parse_opt,
+	.print_qopt	= codel_print_opt,
+	.print_xstats	= codel_print_xstats,
+};
-- 
1.7.9.5