tc : SFB flow scheduler

Supports SFB qdisc (included in linux-2.6.39)

1) Setup phase : accept non default parameters

2) dump information

qdisc sfb 11: parent 1:11 limit 1 max 25 target 20
  increment 0.00050 decrement 0.00005 penalty rate 10 burst 20 (600000ms 60000ms)
 Sent 47991616 bytes 521648 pkt (dropped 549245, overlimits 549245 requeues 0)
 rate 7193Kbit 9774pps backlog 0b 0p requeues 0
  earlydrop 0 penaltydrop 0 bucketdrop 0 queuedrop 549245 childdrop 0 marked 0
  maxqlen 0 maxprob 0.00000 avgprob 0.00000

Signed-off-by: Juliusz Chroboczek <Juliusz.Chroboczek@pps.jussieu.fr>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>

tc/Makefile

@@ -16,6 +16,7 @@ TCMODULES += q_rr.o
 TCMODULES += q_multiq.o
 TCMODULES += q_netem.o
 TCMODULES += q_choke.o
+TCMODULES += q_sfb.o
 TCMODULES += f_rsvp.o
 TCMODULES += f_u32.o
 TCMODULES += f_route.o

tc/q_sfb.c

@@ -0,0 +1,200 @@
+/*
+ * q_sfb.c	Stochastic Fair Blue.
+ *
+ *		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:	Juliusz Chroboczek <jch@pps.jussieu.fr>
+ *
+ */
+
+
+
+#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: ... sfb [ rehash SECS ] [ db SECS ]\n"
+		"	    [ limit PACKETS ] [ max PACKETS ] [ target PACKETS ]\n"
+		"	    [ increment FLOAT ] [ decrement FLOAT ]\n"
+		"	    [ penalty_rate PPS ] [ penalty_burst PACKETS ]\n");
+}
+
+static int get_prob(__u32 *val, const char *arg)
+{
+	double d;
+	char *ptr;
+
+	if (!arg || !*arg)
+		return -1;
+	d = strtod(arg, &ptr);
+	if (!ptr || ptr == arg || d < 0.0 || d > 1.0)
+		return -1;
+	*val = (__u32)(d * SFB_MAX_PROB + 0.5);
+	return 0;
+}
+
+static int sfb_parse_opt(struct qdisc_util *qu, int argc, char **argv,
+			 struct nlmsghdr *n)
+{
+	struct tc_sfb_qopt opt;
+	struct rtattr *tail;
+
+	memset(&opt, 0, sizeof(opt));
+	opt.rehash_interval = 600*1000;
+	opt.warmup_time = 60*1000;
+	opt.penalty_rate = 10;
+	opt.penalty_burst = 20;
+	opt.increment = (SFB_MAX_PROB + 1000) / 2000;
+	opt.decrement = (SFB_MAX_PROB + 10000) / 20000;
+
+	while (argc > 0) {
+	    if (strcmp(*argv, "rehash") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.rehash_interval, *argv, 0)) {
+				fprintf(stderr, "Illegal \"rehash\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "db") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.warmup_time, *argv, 0)) {
+				fprintf(stderr, "Illegal \"db\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "limit") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.limit, *argv, 0)) {
+				fprintf(stderr, "Illegal \"limit\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "max") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.max, *argv, 0)) {
+				fprintf(stderr, "Illegal \"max\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "target") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.bin_size, *argv, 0)) {
+				fprintf(stderr, "Illegal \"target\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "increment") == 0) {
+			NEXT_ARG();
+			if (get_prob(&opt.increment, *argv)) {
+				fprintf(stderr, "Illegal \"increment\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "decrement") == 0) {
+			NEXT_ARG();
+			if (get_prob(&opt.decrement, *argv)) {
+				fprintf(stderr, "Illegal \"decrement\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "penalty_rate") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.penalty_rate, *argv, 0)) {
+				fprintf(stderr, "Illegal \"penalty_rate\"\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "penalty_burst") == 0) {
+			NEXT_ARG();
+			if (get_u32(&opt.penalty_burst, *argv, 0)) {
+				fprintf(stderr, "Illegal \"penalty_burst\"\n");
+				return -1;
+			}
+		} else {
+			fprintf(stderr, "What is \"%s\"?\n", *argv);
+			explain();
+			return -1;
+		}
+		argc--; argv++;
+	}
+
+	if (opt.max == 0) {
+		if (opt.bin_size >= 1)
+			opt.max = (opt.bin_size * 5 + 1) / 4;
+		else
+			opt.max = 25;
+	}
+	if (opt.bin_size == 0)
+		opt.bin_size = (opt.max * 4 + 3) / 5;
+
+	tail = NLMSG_TAIL(n);
+	addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
+	addattr_l(n, 1024, TCA_SFB_PARMS, &opt, sizeof(opt));
+	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+	return 0;
+}
+
+static int sfb_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	struct rtattr *tb[__TCA_SFB_MAX];
+	struct tc_sfb_qopt *qopt;
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_SFB_MAX, opt);
+	if (tb[TCA_SFB_PARMS] == NULL)
+		return -1;
+	qopt = RTA_DATA(tb[TCA_SFB_PARMS]);
+	if (RTA_PAYLOAD(tb[TCA_SFB_PARMS]) < sizeof(*qopt))
+		return -1;
+
+	fprintf(f,
+		"limit %d max %d target %d\n"
+		"  increment %.5f decrement %.5f penalty rate %d burst %d "
+		"(%ums %ums)",
+		qopt->limit, qopt->max, qopt->bin_size,
+		(double)qopt->increment / SFB_MAX_PROB,
+		(double)qopt->decrement / SFB_MAX_PROB,
+		qopt->penalty_rate, qopt->penalty_burst,
+		qopt->rehash_interval, qopt->warmup_time);
+
+	return 0;
+}
+
+static int sfb_print_xstats(struct qdisc_util *qu, FILE *f,
+			    struct rtattr *xstats)
+{
+    struct tc_sfb_xstats *st;
+
+    if (xstats == NULL)
+	    return 0;
+
+    if (RTA_PAYLOAD(xstats) < sizeof(*st))
+	    return -1;
+
+    st = RTA_DATA(xstats);
+    fprintf(f,
+	    "  earlydrop %u penaltydrop %u bucketdrop %u queuedrop %u childdrop %u marked %u\n"
+	    "  maxqlen %u maxprob %.5f avgprob %.5f ",
+	    st->earlydrop, st->penaltydrop, st->bucketdrop, st->queuedrop, st->childdrop,
+	    st->marked,
+	    st->maxqlen, (double)st->maxprob / SFB_MAX_PROB,
+		(double)st->avgprob / SFB_MAX_PROB);
+
+    return 0;
+}
+
+struct qdisc_util sfb_qdisc_util = {
+	.id		= "sfb",
+	.parse_qopt	= sfb_parse_opt,
+	.print_qopt	= sfb_print_opt,
+	.print_xstats	= sfb_print_xstats,
+};