Merge branch 'hsr'

Sebastian Andrzej Siewior says:

====================
I started playing with HSR and run into a problem. Tested latest
upstream -rc and noticed more problems. Now it appears to work.
For testing I have a small three node setup with iperf and ping. While
iperf doesn't complain ping reports missing packets and duplicates.
====================

Link: https://lore.kernel.org/r/20221129164815.128922-1-bigeasy@linutronix.de/Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/hsr/hsr_debugfs.c

@@ -9,7 +9,6 @@
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/debugfs.h>
-#include <linux/jhash.h>
 #include "hsr_main.h"
 #include "hsr_framereg.h"
 
@@ -21,7 +20,6 @@ hsr_node_table_show(struct seq_file *sfp, void *data)
 {
 	struct hsr_priv *priv = (struct hsr_priv *)sfp->private;
 	struct hsr_node *node;
-	int i;
 
 	seq_printf(sfp, "Node Table entries for (%s) device\n",
 		   (priv->prot_version == PRP_V1 ? "PRP" : "HSR"));
@@ -33,28 +31,22 @@ hsr_node_table_show(struct seq_file *sfp, void *data)
 		seq_puts(sfp, "DAN-H\n");
 
 	rcu_read_lock();
-
-	for (i = 0 ; i < priv->hash_buckets; i++) {
-		hlist_for_each_entry_rcu(node, &priv->node_db[i], mac_list) {
-			/* skip self node */
-			if (hsr_addr_is_self(priv, node->macaddress_A))
-				continue;
-			seq_printf(sfp, "%pM ", &node->macaddress_A[0]);
-			seq_printf(sfp, "%pM ", &node->macaddress_B[0]);
-			seq_printf(sfp, "%10lx, ",
-				   node->time_in[HSR_PT_SLAVE_A]);
-			seq_printf(sfp, "%10lx, ",
-				   node->time_in[HSR_PT_SLAVE_B]);
-			seq_printf(sfp, "%14x, ", node->addr_B_port);
-
-			if (priv->prot_version == PRP_V1)
-				seq_printf(sfp, "%5x, %5x, %5x\n",
-					   node->san_a, node->san_b,
-					   (node->san_a == 0 &&
-					    node->san_b == 0));
-			else
-				seq_printf(sfp, "%5x\n", 1);
-		}
+	list_for_each_entry_rcu(node, &priv->node_db, mac_list) {
+		/* skip self node */
+		if (hsr_addr_is_self(priv, node->macaddress_A))
+			continue;
+		seq_printf(sfp, "%pM ", &node->macaddress_A[0]);
+		seq_printf(sfp, "%pM ", &node->macaddress_B[0]);
+		seq_printf(sfp, "%10lx, ", node->time_in[HSR_PT_SLAVE_A]);
+		seq_printf(sfp, "%10lx, ", node->time_in[HSR_PT_SLAVE_B]);
+		seq_printf(sfp, "%14x, ", node->addr_B_port);
+
+		if (priv->prot_version == PRP_V1)
+			seq_printf(sfp, "%5x, %5x, %5x\n",
+				   node->san_a, node->san_b,
+				   (node->san_a == 0 && node->san_b == 0));
+		else
+			seq_printf(sfp, "%5x\n", 1);
 	}
 	rcu_read_unlock();
 	return 0;

net/hsr/hsr_device.c

@@ -219,7 +219,9 @@ static netdev_tx_t hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 		skb->dev = master->dev;
 		skb_reset_mac_header(skb);
 		skb_reset_mac_len(skb);
+		spin_lock_bh(&hsr->seqnr_lock);
 		hsr_forward_skb(skb, master);
+		spin_unlock_bh(&hsr->seqnr_lock);
 	} else {
 		dev_core_stats_tx_dropped_inc(dev);
 		dev_kfree_skb_any(skb);
@@ -278,7 +280,6 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 	__u8 type = HSR_TLV_LIFE_CHECK;
 	struct hsr_sup_payload *hsr_sp;
 	struct hsr_sup_tag *hsr_stag;
-	unsigned long irqflags;
 	struct sk_buff *skb;
 
 	*interval = msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
@@ -299,7 +300,7 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 	set_hsr_stag_HSR_ver(hsr_stag, hsr->prot_version);
 
 	/* From HSRv1 on we have separate supervision sequence numbers. */
-	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
+	spin_lock_bh(&hsr->seqnr_lock);
 	if (hsr->prot_version > 0) {
 		hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
 		hsr->sup_sequence_nr++;
@@ -307,7 +308,6 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 		hsr_stag->sequence_nr = htons(hsr->sequence_nr);
 		hsr->sequence_nr++;
 	}
-	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
 
 	hsr_stag->tlv.HSR_TLV_type = type;
 	/* TODO: Why 12 in HSRv0? */
@@ -318,11 +318,13 @@ static void send_hsr_supervision_frame(struct hsr_port *master,
 	hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
 	ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);
 
-	if (skb_put_padto(skb, ETH_ZLEN))
+	if (skb_put_padto(skb, ETH_ZLEN)) {
+		spin_unlock_bh(&hsr->seqnr_lock);
 		return;
+	}
 
 	hsr_forward_skb(skb, master);
-
+	spin_unlock_bh(&hsr->seqnr_lock);
 	return;
 }
 
@@ -332,7 +334,6 @@ static void send_prp_supervision_frame(struct hsr_port *master,
 	struct hsr_priv *hsr = master->hsr;
 	struct hsr_sup_payload *hsr_sp;
 	struct hsr_sup_tag *hsr_stag;
-	unsigned long irqflags;
 	struct sk_buff *skb;
 
 	skb = hsr_init_skb(master);
@@ -347,7 +348,7 @@ static void send_prp_supervision_frame(struct hsr_port *master,
 	set_hsr_stag_HSR_ver(hsr_stag, (hsr->prot_version ? 1 : 0));
 
 	/* From HSRv1 on we have separate supervision sequence numbers. */
-	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
+	spin_lock_bh(&hsr->seqnr_lock);
 	hsr_stag->sequence_nr = htons(hsr->sup_sequence_nr);
 	hsr->sup_sequence_nr++;
 	hsr_stag->tlv.HSR_TLV_type = PRP_TLV_LIFE_CHECK_DD;
@@ -358,13 +359,12 @@ static void send_prp_supervision_frame(struct hsr_port *master,
 	ether_addr_copy(hsr_sp->macaddress_A, master->dev->dev_addr);
 
 	if (skb_put_padto(skb, ETH_ZLEN)) {
-		spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
+		spin_unlock_bh(&hsr->seqnr_lock);
 		return;
 	}
 
-	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);
-
 	hsr_forward_skb(skb, master);
+	spin_unlock_bh(&hsr->seqnr_lock);
 }
 
 /* Announce (supervision frame) timer function
@@ -444,7 +444,7 @@ void hsr_dev_setup(struct net_device *dev)
 	dev->header_ops = &hsr_header_ops;
 	dev->netdev_ops = &hsr_device_ops;
 	SET_NETDEV_DEVTYPE(dev, &hsr_type);
-	dev->priv_flags |= IFF_NO_QUEUE;
+	dev->priv_flags |= IFF_NO_QUEUE | IFF_DISABLE_NETPOLL;
 
 	dev->needs_free_netdev = true;
 
@@ -485,16 +485,11 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 {
 	bool unregister = false;
 	struct hsr_priv *hsr;
-	int res, i;
+	int res;
 
 	hsr = netdev_priv(hsr_dev);
 	INIT_LIST_HEAD(&hsr->ports);
-	INIT_HLIST_HEAD(&hsr->self_node_db);
-	hsr->hash_buckets = HSR_HSIZE;
-	get_random_bytes(&hsr->hash_seed, sizeof(hsr->hash_seed));
-	for (i = 0; i < hsr->hash_buckets; i++)
-		INIT_HLIST_HEAD(&hsr->node_db[i]);
-
+	INIT_LIST_HEAD(&hsr->node_db);
 	spin_lock_init(&hsr->list_lock);
 
 	eth_hw_addr_set(hsr_dev, slave[0]->dev_addr);

net/hsr/hsr_forward.c

@@ -500,7 +500,6 @@ static void handle_std_frame(struct sk_buff *skb,
 {
 	struct hsr_port *port = frame->port_rcv;
 	struct hsr_priv *hsr = port->hsr;
-	unsigned long irqflags;
 
 	frame->skb_hsr = NULL;
 	frame->skb_prp = NULL;
@@ -510,10 +509,9 @@ static void handle_std_frame(struct sk_buff *skb,
 		frame->is_from_san = true;
 	} else {
 		/* Sequence nr for the master node */
-		spin_lock_irqsave(&hsr->seqnr_lock, irqflags);
+		lockdep_assert_held(&hsr->seqnr_lock);
 		frame->sequence_nr = hsr->sequence_nr;
 		hsr->sequence_nr++;
-		spin_unlock_irqrestore(&hsr->seqnr_lock, irqflags);
 	}
 }
 
@@ -571,23 +569,20 @@ static int fill_frame_info(struct hsr_frame_info *frame,
 	struct ethhdr *ethhdr;
 	__be16 proto;
 	int ret;
-	u32 hash;
 
 	/* Check if skb contains ethhdr */
 	if (skb->mac_len < sizeof(struct ethhdr))
 		return -EINVAL;
 
 	memset(frame, 0, sizeof(*frame));
-
-	ethhdr = (struct ethhdr *)skb_mac_header(skb);
-	hash = hsr_mac_hash(port->hsr, ethhdr->h_source);
 	frame->is_supervision = is_supervision_frame(port->hsr, skb);
-	frame->node_src = hsr_get_node(port, &hsr->node_db[hash], skb,
+	frame->node_src = hsr_get_node(port, &hsr->node_db, skb,
 				       frame->is_supervision,
 				       port->type);
 	if (!frame->node_src)
 		return -1; /* Unknown node and !is_supervision, or no mem */
 
+	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 	frame->is_vlan = false;
 	proto = ethhdr->h_proto;
 
@@ -617,11 +612,13 @@ void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 {
 	struct hsr_frame_info frame;
 
+	rcu_read_lock();
 	if (fill_frame_info(&frame, skb, port) < 0)
 		goto out_drop;
 
 	hsr_register_frame_in(frame.node_src, port, frame.sequence_nr);
 	hsr_forward_do(&frame);
+	rcu_read_unlock();
 	/* Gets called for ingress frames as well as egress from master port.
 	 * So check and increment stats for master port only here.
 	 */
@@ -636,6 +633,7 @@ void hsr_forward_skb(struct sk_buff *skb, struct hsr_port *port)
 	return;
 
 out_drop:
+	rcu_read_unlock();
 	port->dev->stats.tx_dropped++;
 	kfree_skb(skb);
 }

net/hsr/hsr_framereg.h

@@ -28,17 +28,9 @@ struct hsr_frame_info {
 	bool is_from_san;
 };
 
-#ifdef CONFIG_LOCKDEP
-int lockdep_hsr_is_held(spinlock_t *lock);
-#else
-#define lockdep_hsr_is_held(lock)	1
-#endif
-
-u32 hsr_mac_hash(struct hsr_priv *hsr, const unsigned char *addr);
-struct hsr_node *hsr_node_get_first(struct hlist_head *head, spinlock_t *lock);
 void hsr_del_self_node(struct hsr_priv *hsr);
-void hsr_del_nodes(struct hlist_head *node_db);
-struct hsr_node *hsr_get_node(struct hsr_port *port, struct hlist_head *node_db,
+void hsr_del_nodes(struct list_head *node_db);
+struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
 			      struct sk_buff *skb, bool is_sup,
 			      enum hsr_port_type rx_port);
 void hsr_handle_sup_frame(struct hsr_frame_info *frame);
@@ -76,7 +68,9 @@ void prp_handle_san_frame(bool san, enum hsr_port_type port,
 void prp_update_san_info(struct hsr_node *node, bool is_sup);
 
 struct hsr_node {
-	struct hlist_node	mac_list;
+	struct list_head	mac_list;
+	/* Protect R/W access to seq_out */
+	spinlock_t		seq_out_lock;
 	unsigned char		macaddress_A[ETH_ALEN];
 	unsigned char		macaddress_B[ETH_ALEN];
 	/* Local slave through which AddrB frames are received from this node */
@@ -88,6 +82,7 @@ struct hsr_node {
 	bool			san_a;
 	bool			san_b;
 	u16			seq_out[HSR_PT_PORTS];
+	bool			removed;
 	struct rcu_head		rcu_head;
 };
 

net/hsr/hsr_main.h

@@ -47,9 +47,6 @@
 
 #define HSR_V1_SUP_LSDUSIZE		52
 
-#define HSR_HSIZE_SHIFT	8
-#define HSR_HSIZE	BIT(HSR_HSIZE_SHIFT)
-
 /* The helper functions below assumes that 'path' occupies the 4 most
  * significant bits of the 16-bit field shared by 'path' and 'LSDU_size' (or
  * equivalently, the 4 most significant bits of HSR tag byte 14).
@@ -185,11 +182,17 @@ struct hsr_proto_ops {
 	void (*update_san_info)(struct hsr_node *node, bool is_sup);
 };
 
+struct hsr_self_node {
+	unsigned char	macaddress_A[ETH_ALEN];
+	unsigned char	macaddress_B[ETH_ALEN];
+	struct rcu_head	rcu_head;
+};
+
 struct hsr_priv {
 	struct rcu_head		rcu_head;
 	struct list_head	ports;
-	struct hlist_head	node_db[HSR_HSIZE];	/* Known HSR nodes */
-	struct hlist_head	self_node_db;	/* MACs of slaves */
+	struct list_head	node_db;	/* Known HSR nodes */
+	struct hsr_self_node	__rcu *self_node;	/* MACs of slaves */
 	struct timer_list	announce_timer;	/* Supervision frame dispatch */
 	struct timer_list	prune_timer;
 	int announce_count;
@@ -199,8 +202,6 @@ struct hsr_priv {
 	spinlock_t seqnr_lock;	/* locking for sequence_nr */
 	spinlock_t list_lock;	/* locking for node list */
 	struct hsr_proto_ops	*proto_ops;
-	u32 hash_buckets;
-	u32 hash_seed;
 #define PRP_LAN_ID	0x5     /* 0x1010 for A and 0x1011 for B. Bit 0 is set
 				 * based on SLAVE_A or SLAVE_B
 				 */

net/hsr/hsr_netlink.c

@@ -105,7 +105,6 @@ static int hsr_newlink(struct net *src_net, struct net_device *dev,
 static void hsr_dellink(struct net_device *dev, struct list_head *head)
 {
 	struct hsr_priv *hsr = netdev_priv(dev);
-	int i;
 
 	del_timer_sync(&hsr->prune_timer);
 	del_timer_sync(&hsr->announce_timer);
@@ -114,8 +113,7 @@ static void hsr_dellink(struct net_device *dev, struct list_head *head)
 	hsr_del_ports(hsr);
 
 	hsr_del_self_node(hsr);
-	for (i = 0; i < hsr->hash_buckets; i++)
-		hsr_del_nodes(&hsr->node_db[i]);
+	hsr_del_nodes(&hsr->node_db);
 
 	unregister_netdevice_queue(dev, head);
 }

tools/testing/selftests/Makefile

@@ -48,6 +48,7 @@ TARGETS += nci
 TARGETS += net
 TARGETS += net/af_unix
 TARGETS += net/forwarding
+TARGETS += net/hsr
 TARGETS += net/mptcp
 TARGETS += net/openvswitch
 TARGETS += netfilter

tools/testing/selftests/net/hsr/Makefile

+# SPDX-License-Identifier: GPL-2.0
+
+top_srcdir = ../../../../..
+
+TEST_PROGS := hsr_ping.sh
+
+include ../../lib.mk

tools/testing/selftests/net/hsr/config

+CONFIG_IPV6=y
+CONFIG_NET_SCH_NETEM=m
+CONFIG_HSR=y
+CONFIG_VETH=y

tools/testing/selftests/net/hsr/hsr_ping.sh

+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+ret=0
+ksft_skip=4
+ipv6=true
+
+optstring="h4"
+usage() {
+	echo "Usage: $0 [OPTION]"
+	echo -e "\t-4: IPv4 only: disable IPv6 tests (default: test both IPv4 and IPv6)"
+}
+
+while getopts "$optstring" option;do
+	case "$option" in
+	"h")
+		usage $0
+		exit 0
+		;;
+	"4")
+		ipv6=false
+		;;
+	"?")
+		usage $0
+		exit 1
+		;;
+esac
+done
+
+sec=$(date +%s)
+rndh=$(printf %x $sec)-$(mktemp -u XXXXXX)
+ns1="ns1-$rndh"
+ns2="ns2-$rndh"
+ns3="ns3-$rndh"
+
+cleanup()
+{
+	local netns
+	for netns in "$ns1" "$ns2" "$ns3" ;do
+		ip netns del $netns
+	done
+}
+
+ip -Version > /dev/null 2>&1
+if [ $? -ne 0 ];then
+	echo "SKIP: Could not run test without ip tool"
+	exit $ksft_skip
+fi
+
+trap cleanup EXIT
+
+for i in "$ns1" "$ns2" "$ns3" ;do
+	ip netns add $i || exit $ksft_skip
+	ip -net $i link set lo up
+done
+
+echo "INFO: preparing interfaces."
+# Three HSR nodes. Each node has one link to each of its neighbour, two links in total.
+#
+#    ns1eth1 ----- ns2eth1
+#      hsr1         hsr2
+#    ns1eth2       ns2eth2
+#       |            |
+#    ns3eth1      ns3eth2
+#           \    /
+#            hsr3
+#
+# Interfaces
+ip link add ns1eth1 netns "$ns1" type veth peer name ns2eth1 netns "$ns2"
+ip link add ns1eth2 netns "$ns1" type veth peer name ns3eth1 netns "$ns3"
+ip link add ns3eth2 netns "$ns3" type veth peer name ns2eth2 netns "$ns2"
+
+# HSRv0.
+ip -net "$ns1" link add name hsr1 type hsr slave1 ns1eth1 slave2 ns1eth2 supervision 45 version 0 proto 0
+ip -net "$ns2" link add name hsr2 type hsr slave1 ns2eth1 slave2 ns2eth2 supervision 45 version 0 proto 0
+ip -net "$ns3" link add name hsr3 type hsr slave1 ns3eth1 slave2 ns3eth2 supervision 45 version 0 proto 0
+
+# IP for HSR
+ip -net "$ns1" addr add 100.64.0.1/24 dev hsr1
+ip -net "$ns1" addr add dead:beef:1::1/64 dev hsr1 nodad
+ip -net "$ns2" addr add 100.64.0.2/24 dev hsr2
+ip -net "$ns2" addr add dead:beef:1::2/64 dev hsr2 nodad
+ip -net "$ns3" addr add 100.64.0.3/24 dev hsr3
+ip -net "$ns3" addr add dead:beef:1::3/64 dev hsr3 nodad
+
+# All Links up
+ip -net "$ns1" link set ns1eth1 up
+ip -net "$ns1" link set ns1eth2 up
+ip -net "$ns1" link set hsr1 up
+
+ip -net "$ns2" link set ns2eth1 up
+ip -net "$ns2" link set ns2eth2 up
+ip -net "$ns2" link set hsr2 up
+
+ip -net "$ns3" link set ns3eth1 up
+ip -net "$ns3" link set ns3eth2 up
+ip -net "$ns3" link set hsr3 up
+
+# $1: IP address
+is_v6()
+{
+	[ -z "${1##*:*}" ]
+}
+
+do_ping()
+{
+	local netns="$1"
+	local connect_addr="$2"
+	local ping_args="-q -c 2"
+
+	if is_v6 "${connect_addr}"; then
+		$ipv6 || return 0
+		ping_args="${ping_args} -6"
+	fi
+
+	ip netns exec ${netns} ping ${ping_args} $connect_addr >/dev/null
+	if [ $? -ne 0 ] ; then
+		echo "$netns -> $connect_addr connectivity [ FAIL ]" 1>&2
+		ret=1
+		return 1
+	fi
+
+	return 0
+}
+
+do_ping_long()
+{
+	local netns="$1"
+	local connect_addr="$2"
+	local ping_args="-q -c 10"
+
+	if is_v6 "${connect_addr}"; then
+		$ipv6 || return 0
+		ping_args="${ping_args} -6"
+	fi
+
+	OUT="$(LANG=C ip netns exec ${netns} ping ${ping_args} $connect_addr | grep received)"
+	if [ $? -ne 0 ] ; then
+		echo "$netns -> $connect_addr ping [ FAIL ]" 1>&2
+		ret=1
+		return 1
+	fi
+
+	VAL="$(echo $OUT | cut -d' ' -f1-8)"
+	if [ "$VAL" != "10 packets transmitted, 10 received, 0% packet loss," ]
+	then
+		echo "$netns -> $connect_addr ping TEST [ FAIL ]"
+		echo "Expect to send and receive 10 packets and no duplicates."
+		echo "Full message: ${OUT}."
+		ret=1
+		return 1
+	fi
+
+	return 0
+}
+
+stop_if_error()
+{
+	local msg="$1"
+
+	if [ ${ret} -ne 0 ]; then
+		echo "FAIL: ${msg}" 1>&2
+		exit ${ret}
+	fi
+}
+
+
+echo "INFO: Initial validation ping."
+# Each node has to be able each one.
+do_ping "$ns1" 100.64.0.2
+do_ping "$ns2" 100.64.0.1
+do_ping "$ns3" 100.64.0.1
+stop_if_error "Initial validation failed."
+
+do_ping "$ns1" 100.64.0.3
+do_ping "$ns2" 100.64.0.3
+do_ping "$ns3" 100.64.0.2
+
+do_ping "$ns1" dead:beef:1::2
+do_ping "$ns1" dead:beef:1::3
+do_ping "$ns2" dead:beef:1::1
+do_ping "$ns2" dead:beef:1::2
+do_ping "$ns3" dead:beef:1::1
+do_ping "$ns3" dead:beef:1::2
+
+stop_if_error "Initial validation failed."
+
+# Wait until supervisor all supervision frames have been processed and the node
+# entries have been merged. Otherwise duplicate frames will be observed which is
+# valid at this stage.
+WAIT=5
+while [ ${WAIT} -gt 0 ]
+do
+	grep 00:00:00:00:00:00 /sys/kernel/debug/hsr/hsr*/node_table
+	if [ $? -ne 0 ]
+	then
+		break
+	fi
+	sleep 1
+	let WAIT = WAIT - 1
+done
+
+# Just a safety delay in case the above check didn't handle it.
+sleep 1
+
+echo "INFO: Longer ping test."
+do_ping_long "$ns1" 100.64.0.2
+do_ping_long "$ns1" dead:beef:1::2
+do_ping_long "$ns1" 100.64.0.3
+do_ping_long "$ns1" dead:beef:1::3
+
+stop_if_error "Longer ping test failed."
+
+do_ping_long "$ns2" 100.64.0.1
+do_ping_long "$ns2" dead:beef:1::1
+do_ping_long "$ns2" 100.64.0.3
+do_ping_long "$ns2" dead:beef:1::2
+stop_if_error "Longer ping test failed."
+
+do_ping_long "$ns3" 100.64.0.1
+do_ping_long "$ns3" dead:beef:1::1
+do_ping_long "$ns3" 100.64.0.2
+do_ping_long "$ns3" dead:beef:1::2
+stop_if_error "Longer ping test failed."
+
+echo "INFO: Cutting one link."
+do_ping_long "$ns1" 100.64.0.3 &
+
+sleep 3
+ip -net "$ns3" link set ns3eth1 down
+wait
+
+ip -net "$ns3" link set ns3eth1 up
+
+stop_if_error "Failed with one link down."
+
+echo "INFO: Delay the link and drop a few packages."
+tc -net "$ns3" qdisc add dev ns3eth1 root netem delay 50ms
+tc -net "$ns2" qdisc add dev ns2eth1 root netem delay 5ms loss 25%
+
+do_ping_long "$ns1" 100.64.0.2
+do_ping_long "$ns1" 100.64.0.3
+
+stop_if_error "Failed with delay and packetloss."
+
+do_ping_long "$ns2" 100.64.0.1
+do_ping_long "$ns2" 100.64.0.3
+
+stop_if_error "Failed with delay and packetloss."
+
+do_ping_long "$ns3" 100.64.0.1
+do_ping_long "$ns3" 100.64.0.2
+stop_if_error "Failed with delay and packetloss."
+
+echo "INFO: All good."
+exit $ret