selftests: net: Fix bridge backup port test flakiness

The test toggles the carrier of a bridge port in order to test the
bridge backup port feature.

Due to the linkwatch delayed work the carrier change is not always
reflected fast enough to the bridge driver and packets are not forwarded
as the test expects, resulting in failures [1].

Fix by adding a one second delay after a carrier change in places where
a packet is sent immediately after the carrier change.

[1]
 # Backup port
 # -----------
 [...]
 # TEST: swp1 carrier off                                              [ OK ]
 # TEST: No forwarding out of swp1                                     [FAIL]
 [  641.995910] br0: port 1(swp1) entered disabled state
 # TEST: No forwarding out of vx0                                      [ OK ]

Fixes: b408453 ("selftests: net: Add bridge backup port and backup nexthop ID test")
Signed-off-by: Ido Schimmel <[email protected]>
Signed-off-by: NipaLocal <nipa@local>

tools/testing/selftests/net/test_bridge_backup_port.sh

@@ -260,6 +260,7 @@ backup_port()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 1
@@ -285,6 +286,7 @@ backup_port()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 2
@@ -294,6 +296,7 @@ backup_port()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier on"
 	log_test $? 0 "swp1 carrier on"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 3
@@ -315,6 +318,7 @@ backup_port()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 4
@@ -370,6 +374,7 @@ backup_nhid()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 1
@@ -399,6 +404,7 @@ backup_nhid()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 2
@@ -412,6 +418,7 @@ backup_nhid()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier on"
 	log_test $? 0 "swp1 carrier on"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 3
@@ -442,6 +449,7 @@ backup_nhid()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 4
@@ -498,6 +506,7 @@ backup_nhid_invalid()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	log_test $? 0 "swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 mausezahn br0.10 -a $smac -b $dmac -A 198.51.100.1 -B 198.51.100.2 -t ip -p 100 -q -c 1"
 	tc_check_packets $sw1 "dev swp1 egress" 101 0
@@ -605,6 +614,7 @@ backup_nhid_ping()
 
 	run_cmd "ip -n $sw1 link set dev swp1 carrier off"
 	run_cmd "ip -n $sw2 link set dev swp1 carrier off"
+	sleep 1
 
 	run_cmd "ip netns exec $sw1 ping -i 0.1 -c 10 -w $PING_TIMEOUT 192.0.2.66"
 	log_test $? 0 "Ping with backup nexthop ID"