Add support for CAKE qdisc

sch_cake is intended to squeeze the most bandwidth and latency out of even
the slowest ISP links and routers, while presenting an API simple enough
that even an ISP can configure it.

Example of use on a cable ISP uplink:

tc qdisc add dev eth0 cake bandwidth 20Mbit nat docsis ack-filter

To shape a cable download link (ifb and tc-mirred setup elided)

tc qdisc add dev ifb0 cake bandwidth 200mbit nat docsis ingress wash besteffort

Cake is filled with:

* A hybrid Codel/Blue AQM algorithm, "Cobalt", tied to an FQ_Codel
  derived Flow Queuing system, which autoconfigures based on the bandwidth.
* A novel "triple-isolate" mode (the default) which balances per-host
  and per-flow FQ even through NAT.
* An deficit based shaper, that can also be used in an unlimited mode.
* 8 way set associative hashing to reduce flow collisions to a minimum.
* A reasonable interpretation of various diffserv latency/loss tradeoffs.
* Support for zeroing diffserv markings for entering and exiting traffic.
* Support for interacting well with Docsis 3.0 shaper framing.
* Support for DSL framing types and shapers.
* Support for ack filtering.
* Extensive statistics for measuring, loss, ecn markings, latency variation.

Various versions baking have been available as an out of tree build for
kernel versions going back to 3.10, as the embedded router world has been
running a few years behind mainline Linux. A stable version has been
generally available on lede-17.01 and later.

sch_cake replaces a combination of iptables, tc filter, htb and fq_codel
in the sqm-scripts, with sane defaults and vastly simpler configuration.

Cake's principal author is Jonathan Morton, with contributions from
Kevin Darbyshire-Bryant, Toke Høiland-Jørgensen, Sebastian Moeller,
Ryan Mounce, Tony Ambardar, Dean Scarff, Nils Andreas Svee, Dave Täht,
and Loganaden Velvindron.

Testing from Pete Heist, Georgios Amanakis, and the many other members of
the cake@lists.bufferbloat.net mailing list.

Signed-off-by: Dave Taht <dave.taht@gmail.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David Ahern <dsahern@gmail.com>

2 files changed, 791 insertions, 0 deletions

diff --git a/tc/Makefile b/tc/Makefile
index 4525c0fb..36cde2f8 100644
--- a/tc/Makefile
+++ b/tc/Makefile
@@ -66,6 +66,7 @@ TCMODULES += q_codel.o
 TCMODULES += q_fq_codel.o
 TCMODULES += q_fq.o
 TCMODULES += q_pie.o
+TCMODULES += q_cake.o
 TCMODULES += q_hhf.o
 TCMODULES += q_clsact.o
 TCMODULES += e_bpf.o
diff --git a/tc/q_cake.c b/tc/q_cake.c
new file mode 100644
index 00000000..b5476584
--- /dev/null
+++ b/tc/q_cake.c
@@ -0,0 +1,790 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+
+/*
+ * Common Applications Kept Enhanced  --  CAKE
+ *
+ *  Copyright (C) 2014-2018 Jonathan Morton <chromatix99@gmail.com>
+ *  Copyright (C) 2017-2018 Toke Høiland-Jørgensen <toke@toke.dk>
+ */
+
+#include <stddef.h>
+#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 <inttypes.h>
+
+#include "utils.h"
+#include "tc_util.h"
+
+struct cake_preset {
+	char *name;
+	unsigned int target;
+	unsigned int interval;
+};
+
+static struct cake_preset presets[] = {
+	{"datacentre",		5,		100},
+	{"lan",			50,		1000},
+	{"metro",		500,		10000},
+	{"regional",		1500,		30000},
+	{"internet",		5000,		100000},
+	{"oceanic",		15000,		300000},
+	{"satellite",		50000,		1000000},
+	{"interplanetary",	50000000,	1000000000},
+};
+
+static const char * diffserv_names[CAKE_DIFFSERV_MAX] = {
+	[CAKE_DIFFSERV_DIFFSERV3] = "diffserv3",
+	[CAKE_DIFFSERV_DIFFSERV4] = "diffserv4",
+	[CAKE_DIFFSERV_DIFFSERV8] = "diffserv8",
+	[CAKE_DIFFSERV_BESTEFFORT] = "besteffort",
+	[CAKE_DIFFSERV_PRECEDENCE] = "precedence",
+};
+
+static const char * flowmode_names[CAKE_FLOW_MAX] = {
+	[CAKE_FLOW_NONE] = "flowblind",
+	[CAKE_FLOW_SRC_IP] = "srchost",
+	[CAKE_FLOW_DST_IP] = "dsthost",
+	[CAKE_FLOW_HOSTS] = "hosts",
+	[CAKE_FLOW_FLOWS] = "flows",
+	[CAKE_FLOW_DUAL_SRC] = "dual-srchost",
+	[CAKE_FLOW_DUAL_DST] = "dual-dsthost",
+	[CAKE_FLOW_TRIPLE] = "triple-isolate",
+};
+
+static struct cake_preset *find_preset(char *argv)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(presets); i++)
+		if (!strcmp(argv, presets[i].name))
+			return &presets[i];
+	return NULL;
+}
+
+static void explain(void)
+{
+	fprintf(stderr,
+"Usage: ... cake [ bandwidth RATE | unlimited* | autorate_ingress ]\n"
+"                [ rtt TIME | datacentre | lan | metro | regional |\n"
+"                  internet* | oceanic | satellite | interplanetary ]\n"
+"                [ besteffort | diffserv8 | diffserv4 | diffserv3* ]\n"
+"                [ flowblind | srchost | dsthost | hosts | flows |\n"
+"                  dual-srchost | dual-dsthost | triple-isolate* ]\n"
+"                [ nat | nonat* ]\n"
+"                [ wash | nowash* ]\n"
+"                [ ack-filter | ack-filter-aggressive | no-ack-filter* ]\n"
+"                [ memlimit LIMIT ]\n"
+"                [ ptm | atm | noatm* ] [ overhead N | conservative | raw* ]\n"
+"                [ mpu N ] [ ingress | egress* ]\n"
+"                (* marks defaults)\n");
+}
+
+static int cake_parse_opt(struct qdisc_util *qu, int argc, char **argv,
+			  struct nlmsghdr *n, const char *dev)
+{
+	struct cake_preset *preset, *preset_set = NULL;
+	bool overhead_override = false;
+	bool overhead_set = false;
+	unsigned int interval = 0;
+	unsigned int diffserv = 0;
+	unsigned int memlimit = 0;
+	unsigned int target = 0;
+	__u64 bandwidth = 0;
+	int ack_filter = -1;
+	struct rtattr *tail;
+	int unlimited = 0;
+	int flowmode = -1;
+	int autorate = -1;
+	int ingress = -1;
+	int overhead = 0;
+	int wash = -1;
+	int nat = -1;
+	int atm = -1;
+	int mpu = 0;
+
+	while (argc > 0) {
+		if (strcmp(*argv, "bandwidth") == 0) {
+			NEXT_ARG();
+			if (get_rate64(&bandwidth, *argv)) {
+				fprintf(stderr, "Illegal \"bandwidth\"\n");
+				return -1;
+			}
+			unlimited = 0;
+			autorate = 0;
+		} else if (strcmp(*argv, "unlimited") == 0) {
+			bandwidth = 0;
+			unlimited = 1;
+			autorate = 0;
+		} else if (strcmp(*argv, "autorate_ingress") == 0) {
+			autorate = 1;
+		} else if (strcmp(*argv, "rtt") == 0) {
+			NEXT_ARG();
+			if (get_time(&interval, *argv)) {
+				fprintf(stderr, "Illegal \"rtt\"\n");
+				return -1;
+			}
+			target = interval / 20;
+			if (!target)
+				target = 1;
+		} else if ((preset = find_preset(*argv))) {
+			if (preset_set)
+				duparg(*argv, preset_set->name);
+			preset_set = preset;
+			target = preset->target;
+			interval = preset->interval;
+		} else if (strcmp(*argv, "besteffort") == 0) {
+			diffserv = CAKE_DIFFSERV_BESTEFFORT;
+		} else if (strcmp(*argv, "precedence") == 0) {
+			diffserv = CAKE_DIFFSERV_PRECEDENCE;
+		} else if (strcmp(*argv, "diffserv8") == 0) {
+			diffserv = CAKE_DIFFSERV_DIFFSERV8;
+		} else if (strcmp(*argv, "diffserv4") == 0) {
+			diffserv = CAKE_DIFFSERV_DIFFSERV4;
+		} else if (strcmp(*argv, "diffserv") == 0) {
+			diffserv = CAKE_DIFFSERV_DIFFSERV4;
+		} else if (strcmp(*argv, "diffserv3") == 0) {
+			diffserv = CAKE_DIFFSERV_DIFFSERV3;
+		} else if (strcmp(*argv, "nowash") == 0) {
+			wash = 0;
+		} else if (strcmp(*argv, "wash") == 0) {
+			wash = 1;
+		} else if (strcmp(*argv, "flowblind") == 0) {
+			flowmode = CAKE_FLOW_NONE;
+		} else if (strcmp(*argv, "srchost") == 0) {
+			flowmode = CAKE_FLOW_SRC_IP;
+		} else if (strcmp(*argv, "dsthost") == 0) {
+			flowmode = CAKE_FLOW_DST_IP;
+		} else if (strcmp(*argv, "hosts") == 0) {
+			flowmode = CAKE_FLOW_HOSTS;
+		} else if (strcmp(*argv, "flows") == 0) {
+			flowmode = CAKE_FLOW_FLOWS;
+		} else if (strcmp(*argv, "dual-srchost") == 0) {
+			flowmode = CAKE_FLOW_DUAL_SRC;
+		} else if (strcmp(*argv, "dual-dsthost") == 0) {
+			flowmode = CAKE_FLOW_DUAL_DST;
+		} else if (strcmp(*argv, "triple-isolate") == 0) {
+			flowmode = CAKE_FLOW_TRIPLE;
+		} else if (strcmp(*argv, "nat") == 0) {
+			nat = 1;
+		} else if (strcmp(*argv, "nonat") == 0) {
+			nat = 0;
+		} else if (strcmp(*argv, "ptm") == 0) {
+			atm = CAKE_ATM_PTM;
+		} else if (strcmp(*argv, "atm") == 0) {
+			atm = CAKE_ATM_ATM;
+		} else if (strcmp(*argv, "noatm") == 0) {
+			atm = CAKE_ATM_NONE;
+		} else if (strcmp(*argv, "raw") == 0) {
+			atm = CAKE_ATM_NONE;
+			overhead = 0;
+			overhead_set = true;
+			overhead_override = true;
+		} else if (strcmp(*argv, "conservative") == 0) {
+			/*
+			 * Deliberately over-estimate overhead:
+			 * one whole ATM cell plus ATM framing.
+			 * A safe choice if the actual overhead is unknown.
+			 */
+			atm = CAKE_ATM_ATM;
+			overhead = 48;
+			overhead_set = true;
+
+		/* Various ADSL framing schemes, all over ATM cells */
+		} else if (strcmp(*argv, "ipoa-vcmux") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 8;
+			overhead_set = true;
+		} else if (strcmp(*argv, "ipoa-llcsnap") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 16;
+			overhead_set = true;
+		} else if (strcmp(*argv, "bridged-vcmux") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 24;
+			overhead_set = true;
+		} else if (strcmp(*argv, "bridged-llcsnap") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 32;
+			overhead_set = true;
+		} else if (strcmp(*argv, "pppoa-vcmux") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 10;
+			overhead_set = true;
+		} else if (strcmp(*argv, "pppoa-llc") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 14;
+			overhead_set = true;
+		} else if (strcmp(*argv, "pppoe-vcmux") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 32;
+			overhead_set = true;
+		} else if (strcmp(*argv, "pppoe-llcsnap") == 0) {
+			atm = CAKE_ATM_ATM;
+			overhead += 40;
+			overhead_set = true;
+
+		/* Typical VDSL2 framing schemes, both over PTM */
+		/* PTM has 64b/65b coding which absorbs some bandwidth */
+		} else if (strcmp(*argv, "pppoe-ptm") == 0) {
+			/* 2B PPP + 6B PPPoE + 6B dest MAC + 6B src MAC
+			 * + 2B ethertype + 4B Frame Check Sequence
+			 * + 1B Start of Frame (S) + 1B End of Frame (Ck)
+			 * + 2B TC-CRC (PTM-FCS) = 30B
+			 */
+			atm = CAKE_ATM_PTM;
+			overhead += 30;
+			overhead_set = true;
+		} else if (strcmp(*argv, "bridged-ptm") == 0) {
+			/* 6B dest MAC + 6B src MAC + 2B ethertype
+			 * + 4B Frame Check Sequence
+			 * + 1B Start of Frame (S) + 1B End of Frame (Ck)
+			 * + 2B TC-CRC (PTM-FCS) = 22B
+			 */
+			atm = CAKE_ATM_PTM;
+			overhead += 22;
+			overhead_set = true;
+		} else if (strcmp(*argv, "via-ethernet") == 0) {
+			/*
+			 * We used to use this flag to manually compensate for
+			 * Linux including the Ethernet header on Ethernet-type
+			 * interfaces, but not on IP-type interfaces.
+			 *
+			 * It is no longer needed, because Cake now adjusts for
+			 * that automatically, and is thus ignored.
+			 *
+			 * It would be deleted entirely, but it appears in the
+			 * stats output when the automatic compensation is
+			 * active.
+			 */
+		} else if (strcmp(*argv, "ethernet") == 0) {
+			/* ethernet pre-amble & interframe gap & FCS
+			 * you may need to add vlan tag
+			 */
+			overhead += 38;
+			overhead_set = true;
+			mpu = 84;
+
+		/* Additional Ethernet-related overhead used by some ISPs */
+		} else if (strcmp(*argv, "ether-vlan") == 0) {
+			/* 802.1q VLAN tag - may be repeated */
+			overhead += 4;
+			overhead_set = true;
+
+		/*
+		 * DOCSIS cable shapers account for Ethernet frame with FCS,
+		 * but not interframe gap or preamble.
+		 */
+		} else if (strcmp(*argv, "docsis") == 0) {
+			atm = CAKE_ATM_NONE;
+			overhead += 18;
+			overhead_set = true;
+			mpu = 64;
+		} else if (strcmp(*argv, "overhead") == 0) {
+			char *p = NULL;
+
+			NEXT_ARG();
+			overhead = strtol(*argv, &p, 10);
+			if (!p || *p || !*argv ||
+			    overhead < -64 || overhead > 256) {
+				fprintf(stderr,
+					"Illegal \"overhead\", valid range is -64 to 256\\n");
+				return -1;
+			}
+			overhead_set = true;
+
+		} else if (strcmp(*argv, "mpu") == 0) {
+			char *p = NULL;
+
+			NEXT_ARG();
+			mpu = strtol(*argv, &p, 10);
+			if (!p || *p || !*argv || mpu < 0 || mpu > 256) {
+				fprintf(stderr,
+					"Illegal \"mpu\", valid range is 0 to 256\\n");
+				return -1;
+			}
+		} else if (strcmp(*argv, "ingress") == 0) {
+			ingress = 1;
+		} else if (strcmp(*argv, "egress") == 0) {
+			ingress = 0;
+		} else if (strcmp(*argv, "no-ack-filter") == 0) {
+			ack_filter = CAKE_ACK_NONE;
+		} else if (strcmp(*argv, "ack-filter") == 0) {
+			ack_filter = CAKE_ACK_FILTER;
+		} else if (strcmp(*argv, "ack-filter-aggressive") == 0) {
+			ack_filter = CAKE_ACK_AGGRESSIVE;
+		} else if (strcmp(*argv, "memlimit") == 0) {
+			NEXT_ARG();
+			if (get_size(&memlimit, *argv)) {
+				fprintf(stderr,
+					"Illegal value for \"memlimit\": \"%s\"\n", *argv);
+				return -1;
+			}
+		} else if (strcmp(*argv, "help") == 0) {
+			explain();
+			return -1;
+		} 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);
+	if (bandwidth || unlimited)
+		addattr_l(n, 1024, TCA_CAKE_BASE_RATE64, &bandwidth,
+			  sizeof(bandwidth));
+	if (diffserv)
+		addattr_l(n, 1024, TCA_CAKE_DIFFSERV_MODE, &diffserv,
+			  sizeof(diffserv));
+	if (atm != -1)
+		addattr_l(n, 1024, TCA_CAKE_ATM, &atm, sizeof(atm));
+	if (flowmode != -1)
+		addattr_l(n, 1024, TCA_CAKE_FLOW_MODE, &flowmode,
+			  sizeof(flowmode));
+	if (overhead_set)
+		addattr_l(n, 1024, TCA_CAKE_OVERHEAD, &overhead,
+			  sizeof(overhead));
+	if (overhead_override) {
+		unsigned int zero = 0;
+
+		addattr_l(n, 1024, TCA_CAKE_RAW, &zero, sizeof(zero));
+	}
+	if (mpu > 0)
+		addattr_l(n, 1024, TCA_CAKE_MPU, &mpu, sizeof(mpu));
+	if (interval)
+		addattr_l(n, 1024, TCA_CAKE_RTT, &interval, sizeof(interval));
+	if (target)
+		addattr_l(n, 1024, TCA_CAKE_TARGET, &target, sizeof(target));
+	if (autorate != -1)
+		addattr_l(n, 1024, TCA_CAKE_AUTORATE, &autorate,
+			  sizeof(autorate));
+	if (memlimit)
+		addattr_l(n, 1024, TCA_CAKE_MEMORY, &memlimit,
+			  sizeof(memlimit));
+	if (nat != -1)
+		addattr_l(n, 1024, TCA_CAKE_NAT, &nat, sizeof(nat));
+	if (wash != -1)
+		addattr_l(n, 1024, TCA_CAKE_WASH, &wash, sizeof(wash));
+	if (ingress != -1)
+		addattr_l(n, 1024, TCA_CAKE_INGRESS, &ingress, sizeof(ingress));
+	if (ack_filter != -1)
+		addattr_l(n, 1024, TCA_CAKE_ACK_FILTER, &ack_filter,
+			  sizeof(ack_filter));
+
+	tail->rta_len = (void *) NLMSG_TAIL(n) - (void *) tail;
+	return 0;
+}
+
+static void cake_print_mode(unsigned int value, unsigned int max,
+			    const char *key, const char **table)
+{
+	if (value < max && table[value]) {
+		print_string(PRINT_ANY, key, "%s ", table[value]);
+	} else {
+		print_string(PRINT_JSON, key, NULL, "unknown");
+		print_string(PRINT_FP, NULL, "(?%s?)", key);
+	}
+}
+
+static int cake_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
+{
+	struct rtattr *tb[TCA_CAKE_MAX + 1];
+	unsigned int interval = 0;
+	unsigned int memlimit = 0;
+	__u64 bandwidth = 0;
+	int ack_filter = 0;
+	int split_gso = 0;
+	int overhead = 0;
+	int autorate = 0;
+	int ingress = 0;
+	int wash = 0;
+	int raw = 0;
+	int mpu = 0;
+	int atm = 0;
+	int nat = 0;
+
+	SPRINT_BUF(b1);
+	SPRINT_BUF(b2);
+
+	if (opt == NULL)
+		return 0;
+
+	parse_rtattr_nested(tb, TCA_CAKE_MAX, opt);
+
+	if (tb[TCA_CAKE_BASE_RATE64] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_BASE_RATE64]) >= sizeof(bandwidth)) {
+		bandwidth = rta_getattr_u64(tb[TCA_CAKE_BASE_RATE64]);
+		if (bandwidth) {
+			print_uint(PRINT_JSON, "bandwidth", NULL, bandwidth);
+			print_string(PRINT_FP, NULL, "bandwidth %s ",
+				     sprint_rate(bandwidth, b1));
+		} else
+			print_string(PRINT_ANY, "bandwidth", "bandwidth %s ",
+				     "unlimited");
+	}
+	if (tb[TCA_CAKE_AUTORATE] &&
+		RTA_PAYLOAD(tb[TCA_CAKE_AUTORATE]) >= sizeof(__u32)) {
+		autorate = rta_getattr_u32(tb[TCA_CAKE_AUTORATE]);
+		if (autorate == 1)
+			print_string(PRINT_ANY, "autorate", "autorate_%s ",
+				     "ingress");
+		else if (autorate)
+			print_string(PRINT_ANY, "autorate", "(?autorate?) ",
+				     "unknown");
+	}
+	if (tb[TCA_CAKE_DIFFSERV_MODE] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_DIFFSERV_MODE]) >= sizeof(__u32)) {
+		cake_print_mode(rta_getattr_u32(tb[TCA_CAKE_DIFFSERV_MODE]),
+				CAKE_DIFFSERV_MAX, "diffserv", diffserv_names);
+	}
+	if (tb[TCA_CAKE_FLOW_MODE] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_FLOW_MODE]) >= sizeof(__u32)) {
+		cake_print_mode(rta_getattr_u32(tb[TCA_CAKE_FLOW_MODE]),
+				CAKE_FLOW_MAX, "flowmode", flowmode_names);
+	}
+
+	if (tb[TCA_CAKE_NAT] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_NAT]) >= sizeof(__u32)) {
+		nat = rta_getattr_u32(tb[TCA_CAKE_NAT]);
+	}
+
+	if (nat)
+		print_string(PRINT_FP, NULL, "nat ", NULL);
+	print_bool(PRINT_JSON, "nat", NULL, nat);
+
+	if (tb[TCA_CAKE_WASH] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_WASH]) >= sizeof(__u32)) {
+		wash = rta_getattr_u32(tb[TCA_CAKE_WASH]);
+	}
+	if (tb[TCA_CAKE_ATM] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_ATM]) >= sizeof(__u32)) {
+		atm = rta_getattr_u32(tb[TCA_CAKE_ATM]);
+	}
+	if (tb[TCA_CAKE_OVERHEAD] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_OVERHEAD]) >= sizeof(__s32)) {
+		overhead = *(__s32 *) RTA_DATA(tb[TCA_CAKE_OVERHEAD]);
+	}
+	if (tb[TCA_CAKE_MPU] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_MPU]) >= sizeof(__u32)) {
+		mpu = rta_getattr_u32(tb[TCA_CAKE_MPU]);
+	}
+	if (tb[TCA_CAKE_INGRESS] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_INGRESS]) >= sizeof(__u32)) {
+		ingress = rta_getattr_u32(tb[TCA_CAKE_INGRESS]);
+	}
+	if (tb[TCA_CAKE_ACK_FILTER] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_ACK_FILTER]) >= sizeof(__u32)) {
+		ack_filter = rta_getattr_u32(tb[TCA_CAKE_ACK_FILTER]);
+	}
+	if (tb[TCA_CAKE_SPLIT_GSO] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_SPLIT_GSO]) >= sizeof(__u32)) {
+		split_gso = rta_getattr_u32(tb[TCA_CAKE_SPLIT_GSO]);
+	}
+	if (tb[TCA_CAKE_RAW]) {
+		raw = 1;
+	}
+	if (tb[TCA_CAKE_RTT] &&
+	    RTA_PAYLOAD(tb[TCA_CAKE_RTT]) >= sizeof(__u32)) {
+		interval = rta_getattr_u32(tb[TCA_CAKE_RTT]);
+	}
+
+	if (wash)
+		print_string(PRINT_FP, NULL, "wash ", NULL);
+	print_bool(PRINT_JSON, "wash", NULL, wash);
+
+	if (ingress)
+		print_string(PRINT_FP, NULL, "ingress ", NULL);
+	print_bool(PRINT_JSON, "ingress", NULL, ingress);
+
+	if (ack_filter == CAKE_ACK_AGGRESSIVE)
+		print_string(PRINT_ANY, "ack-filter", "ack-filter-%s ",
+			     "aggressive");
+	else if (ack_filter == CAKE_ACK_FILTER)
+		print_string(PRINT_ANY, "ack-filter", "ack-filter ", "enabled");
+	else
+		print_string(PRINT_JSON, "ack-filter", NULL, "disabled");
+
+	if (split_gso)
+		print_string(PRINT_FP, NULL, "split-gso ", NULL);
+	print_bool(PRINT_JSON, "split_gso", NULL, split_gso);
+
+	if (interval)
+		print_string(PRINT_FP, NULL, "rtt %s ",
+			     sprint_time(interval, b2));
+	print_uint(PRINT_JSON, "rtt", NULL, interval);
+
+	if (raw)
+		print_string(PRINT_FP, NULL, "raw ", NULL);
+	print_bool(PRINT_JSON, "raw", NULL, raw);
+
+	if (atm == CAKE_ATM_ATM)
+		print_string(PRINT_ANY, "atm", "%s ", "atm");
+	else if (atm == CAKE_ATM_PTM)
+		print_string(PRINT_ANY, "atm", "%s ", "ptm");
+	else if (!raw)
+		print_string(PRINT_ANY, "atm", "%s ", "noatm");
+
+	print_int(PRINT_ANY, "overhead", "overhead %d ", overhead);
+
+	if (mpu)
+		print_uint(PRINT_ANY, "mpu", "mpu %u ", mpu);
+
+	if (memlimit) {
+		print_uint(PRINT_JSON, "memlimit", NULL, memlimit);
+		print_string(PRINT_FP, NULL, "memlimit %s",
+			     sprint_size(memlimit, b1));
+	}
+
+	return 0;
+}
+
+static void cake_print_json_tin(struct rtattr **tstat)
+{
+#define PRINT_TSTAT_JSON(type, name, attr) if (tstat[TCA_CAKE_TIN_STATS_ ## attr]) \
+		print_u64(PRINT_JSON, name, NULL,			\
+			rta_getattr_ ## type((struct rtattr *)		\
+					     tstat[TCA_CAKE_TIN_STATS_ ## attr]))
+
+	open_json_object(NULL);
+	PRINT_TSTAT_JSON(u64, "threshold_rate", THRESHOLD_RATE64);
+	PRINT_TSTAT_JSON(u64, "sent_bytes", SENT_BYTES64);
+	PRINT_TSTAT_JSON(u32, "backlog_bytes", BACKLOG_BYTES);
+	PRINT_TSTAT_JSON(u32, "target_us", TARGET_US);
+	PRINT_TSTAT_JSON(u32, "interval_us", INTERVAL_US);
+	PRINT_TSTAT_JSON(u32, "peak_delay_us", PEAK_DELAY_US);
+	PRINT_TSTAT_JSON(u32, "avg_delay_us", AVG_DELAY_US);
+	PRINT_TSTAT_JSON(u32, "base_delay_us", BASE_DELAY_US);
+	PRINT_TSTAT_JSON(u32, "sent_packets", SENT_PACKETS);
+	PRINT_TSTAT_JSON(u32, "way_indirect_hits", WAY_INDIRECT_HITS);
+	PRINT_TSTAT_JSON(u32, "way_misses", WAY_MISSES);
+	PRINT_TSTAT_JSON(u32, "way_collisions", WAY_COLLISIONS);
+	PRINT_TSTAT_JSON(u32, "drops", DROPPED_PACKETS);
+	PRINT_TSTAT_JSON(u32, "ecn_mark", ECN_MARKED_PACKETS);
+	PRINT_TSTAT_JSON(u32, "ack_drops", ACKS_DROPPED_PACKETS);
+	PRINT_TSTAT_JSON(u32, "sparse_flows", SPARSE_FLOWS);
+	PRINT_TSTAT_JSON(u32, "bulk_flows", BULK_FLOWS);
+	PRINT_TSTAT_JSON(u32, "unresponsive_flows", UNRESPONSIVE_FLOWS);
+	PRINT_TSTAT_JSON(u32, "max_pkt_len", MAX_SKBLEN);
+	PRINT_TSTAT_JSON(u32, "flow_quantum", FLOW_QUANTUM);
+	close_json_object();
+
+#undef PRINT_TSTAT_JSON
+}
+
+static int cake_print_xstats(struct qdisc_util *qu, FILE *f,
+			     struct rtattr *xstats)
+{
+	struct rtattr *st[TCA_CAKE_STATS_MAX + 1];
+	SPRINT_BUF(b1);
+	int i;
+
+	if (xstats == NULL)
+		return 0;
+
+#define GET_STAT_U32(attr) rta_getattr_u32(st[TCA_CAKE_STATS_ ## attr])
+#define GET_STAT_S32(attr) (*(__s32 *)RTA_DATA(st[TCA_CAKE_STATS_ ## attr]))
+#define GET_STAT_U64(attr) rta_getattr_u64(st[TCA_CAKE_STATS_ ## attr])
+
+	parse_rtattr_nested(st, TCA_CAKE_STATS_MAX, xstats);
+
+	if (st[TCA_CAKE_STATS_MEMORY_USED] &&
+	    st[TCA_CAKE_STATS_MEMORY_LIMIT]) {
+		print_string(PRINT_FP, NULL, " memory used: %s",
+			sprint_size(GET_STAT_U32(MEMORY_USED), b1));
+
+		print_string(PRINT_FP, NULL, " of %s\n",
+			sprint_size(GET_STAT_U32(MEMORY_LIMIT), b1));
+
+		print_uint(PRINT_JSON, "memory_used", NULL,
+			GET_STAT_U32(MEMORY_USED));
+		print_uint(PRINT_JSON, "memory_limit", NULL,
+			GET_STAT_U32(MEMORY_LIMIT));
+	}
+
+	if (st[TCA_CAKE_STATS_CAPACITY_ESTIMATE64]) {
+		print_string(PRINT_FP, NULL, " capacity estimate: %s\n",
+			sprint_rate(GET_STAT_U64(CAPACITY_ESTIMATE64), b1));
+		print_uint(PRINT_JSON, "capacity_estimate", NULL,
+			GET_STAT_U64(CAPACITY_ESTIMATE64));
+	}
+
+	if (st[TCA_CAKE_STATS_MIN_NETLEN] &&
+	    st[TCA_CAKE_STATS_MAX_NETLEN]) {
+		print_uint(PRINT_ANY, "min_network_size",
+			   " min/max network layer size: %12u",
+			   GET_STAT_U32(MIN_NETLEN));
+		print_uint(PRINT_ANY, "max_network_size",
+			   " /%8u\n", GET_STAT_U32(MAX_NETLEN));
+	}
+
+	if (st[TCA_CAKE_STATS_MIN_ADJLEN] &&
+	    st[TCA_CAKE_STATS_MAX_ADJLEN]) {
+		print_uint(PRINT_ANY, "min_adj_size",
+			   " min/max overhead-adjusted size: %8u",
+			   GET_STAT_U32(MIN_ADJLEN));
+		print_uint(PRINT_ANY, "max_adj_size",
+			   " /%8u\n", GET_STAT_U32(MAX_ADJLEN));
+	}
+
+	if (st[TCA_CAKE_STATS_AVG_NETOFF])
+		print_uint(PRINT_ANY, "avg_hdr_offset",
+			   " average network hdr offset: %12u\n\n",
+			   GET_STAT_U32(AVG_NETOFF));
+
+	/* class stats */
+	if (st[TCA_CAKE_STATS_DEFICIT])
+		print_int(PRINT_ANY, "deficit", "  deficit %u",
+			  GET_STAT_S32(DEFICIT));
+	if (st[TCA_CAKE_STATS_COBALT_COUNT])
+		print_uint(PRINT_ANY, "count", " count %u",
+			   GET_STAT_U32(COBALT_COUNT));
+
+	if (st[TCA_CAKE_STATS_DROPPING] && GET_STAT_U32(DROPPING)) {
+		print_bool(PRINT_ANY, "dropping", " dropping", true);
+		if (st[TCA_CAKE_STATS_DROP_NEXT_US]) {
+			int drop_next = GET_STAT_S32(DROP_NEXT_US);
+
+			if (drop_next < 0) {
+				print_string(PRINT_FP, NULL, " drop_next -%s",
+					sprint_time(drop_next, b1));
+			} else {
+				print_uint(PRINT_JSON, "drop_next", NULL,
+					drop_next);
+				print_string(PRINT_FP, NULL, " drop_next %s",
+					sprint_time(drop_next, b1));
+			}
+		}
+	}
+
+	if (st[TCA_CAKE_STATS_P_DROP]) {
+		print_uint(PRINT_ANY, "blue_prob", " blue_prob %u",
+			   GET_STAT_U32(P_DROP));
+		if (st[TCA_CAKE_STATS_BLUE_TIMER_US]) {
+			int blue_timer = GET_STAT_S32(BLUE_TIMER_US);
+
+			if (blue_timer < 0) {
+				print_string(PRINT_FP, NULL, " blue_timer -%s",
+					sprint_time(blue_timer, b1));
+			} else {
+				print_uint(PRINT_JSON, "blue_timer", NULL,
+					blue_timer);
+				print_string(PRINT_FP, NULL, " blue_timer %s",
+					sprint_time(blue_timer, b1));
+			}
+		}
+	}
+
+#undef GET_STAT_U32
+#undef GET_STAT_S32
+#undef GET_STAT_U64
+
+	if (st[TCA_CAKE_STATS_TIN_STATS]) {
+		struct rtattr *tstat[TC_CAKE_MAX_TINS][TCA_CAKE_TIN_STATS_MAX + 1];
+		struct rtattr *tins[TC_CAKE_MAX_TINS + 1];
+		int num_tins = 0;
+
+		parse_rtattr_nested(tins, TC_CAKE_MAX_TINS,
+				    st[TCA_CAKE_STATS_TIN_STATS]);
+
+		for (i = 1; i <= TC_CAKE_MAX_TINS && tins[i]; i++) {
+			parse_rtattr_nested(tstat[i-1], TCA_CAKE_TIN_STATS_MAX,
+					    tins[i]);
+			num_tins++;
+		}
+
+		if (!num_tins)
+			return 0;
+
+		if (is_json_context()) {
+			open_json_array(PRINT_JSON, "tins");
+			for (i = 0; i < num_tins; i++)
+				cake_print_json_tin(tstat[i]);
+			close_json_array(PRINT_JSON, NULL);
+
+			return 0;
+		}
+
+
+		switch (num_tins) {
+		case 3:
+			fprintf(f, "                   Bulk  Best Effort        Voice\n");
+			break;
+
+		case 4:
+			fprintf(f, "                   Bulk  Best Effort        Video        Voice\n");
+			break;
+
+		default:
+			fprintf(f, "          ");
+			for (i = 0; i < num_tins; i++)
+				fprintf(f, "        Tin %u", i);
+			fprintf(f, "\n");
+		};
+
+#define GET_TSTAT(i, attr) (tstat[i][TCA_CAKE_TIN_STATS_ ## attr])
+#define PRINT_TSTAT(name, attr, fmts, val)	do {		\
+			if (GET_TSTAT(0, attr)) {		\
+				fprintf(f, name);		\
+				for (i = 0; i < num_tins; i++)	\
+					fprintf(f, " %12" fmts,	val);	\
+				fprintf(f, "\n");			\
+			}						\
+		} while (0)
+
+#define SPRINT_TSTAT(pfunc, type, name, attr) PRINT_TSTAT(		\
+			name, attr, "s", sprint_ ## pfunc(		\
+				rta_getattr_ ## type(GET_TSTAT(i, attr)), b1))
+
+#define PRINT_TSTAT_U32(name, attr)	PRINT_TSTAT(			\
+			name, attr, "u", rta_getattr_u32(GET_TSTAT(i, attr)))
+
+#define PRINT_TSTAT_U64(name, attr)	PRINT_TSTAT(			\
+			name, attr, "llu", rta_getattr_u64(GET_TSTAT(i, attr)))
+
+		SPRINT_TSTAT(rate, u64, "  thresh  ", THRESHOLD_RATE64);
+		SPRINT_TSTAT(time, u32, "  target  ", TARGET_US);
+		SPRINT_TSTAT(time, u32, "  interval", INTERVAL_US);
+		SPRINT_TSTAT(time, u32, "  pk_delay", PEAK_DELAY_US);
+		SPRINT_TSTAT(time, u32, "  av_delay", AVG_DELAY_US);
+		SPRINT_TSTAT(time, u32, "  sp_delay", BASE_DELAY_US);
+		SPRINT_TSTAT(size, u32, "  backlog ", BACKLOG_BYTES);
+
+		PRINT_TSTAT_U32("  pkts    ", SENT_PACKETS);
+		PRINT_TSTAT_U64("  bytes   ", SENT_BYTES64);
+
+		PRINT_TSTAT_U32("  way_inds", WAY_INDIRECT_HITS);
+		PRINT_TSTAT_U32("  way_miss", WAY_MISSES);
+		PRINT_TSTAT_U32("  way_cols", WAY_COLLISIONS);
+		PRINT_TSTAT_U32("  drops   ", DROPPED_PACKETS);
+		PRINT_TSTAT_U32("  marks   ", ECN_MARKED_PACKETS);
+		PRINT_TSTAT_U32("  ack_drop", ACKS_DROPPED_PACKETS);
+		PRINT_TSTAT_U32("  sp_flows", SPARSE_FLOWS);
+		PRINT_TSTAT_U32("  bk_flows", BULK_FLOWS);
+		PRINT_TSTAT_U32("  un_flows", UNRESPONSIVE_FLOWS);
+		PRINT_TSTAT_U32("  max_len ", MAX_SKBLEN);
+		PRINT_TSTAT_U32("  quantum ", FLOW_QUANTUM);
+
+#undef GET_STAT
+#undef PRINT_TSTAT
+#undef SPRINT_TSTAT
+#undef PRINT_TSTAT_U32
+#undef PRINT_TSTAT_U64
+	}
+	return 0;
+}
+
+struct qdisc_util cake_qdisc_util = {
+	.id		= "cake",
+	.parse_qopt	= cake_parse_opt,
+	.print_qopt	= cake_print_opt,
+	.print_xstats	= cake_print_xstats,
+};