selftests: mptcp: join: validate MPJ SYN TX MIB counters

A few new MPJoinSynTx MIB counters have been added in a previous commit.
They are being validated here in mptcp_join.sh selftest, each time the
number of received MPJ are checked.

Most of the time, the number of sent SYN+MPJ is the same as the received
ones. But sometimes, there are more, because there are dropped, or there
are errors.

While at it, the "no MPC reuse with single endpoint" subtest has been
modified to force a bind() error.
Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240902-net-next-mptcp-mib-mpjtx-misc-v1-6-d3e0f3773b90@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -67,6 +67,10 @@ unset join_fail_nr
 unset join_rst_nr
 unset join_infi_nr
 unset join_corrupted_pkts
+unset join_syn_tx
+unset join_create_err
+unset join_bind_err
+unset join_connect_err
 
 # generated using "nfbpf_compile '(ip && (ip[54] & 0xf0) == 0x30) ||
 #				  (ip6 && (ip6[74] & 0xf0) == 0x30)'"
@@ -1336,6 +1340,54 @@ chk_infi_nr()
 	fi
 }
 
+chk_join_tx_nr()
+{
+	local syn_tx=${join_syn_tx:-0}
+	local create=${join_create_err:-0}
+	local bind=${join_bind_err:-0}
+	local connect=${join_connect_err:-0}
+	local rc=${KSFT_PASS}
+	local count
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTx")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$syn_tx" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx"
+		fail_test "got $count JOIN[s] syn tx expected $syn_tx"
+	fi
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTxCreatSkErr")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$create" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx create socket error"
+		fail_test "got $count JOIN[s] syn tx create socket error expected $create"
+	fi
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTxBindErr")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$bind" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx bind error"
+		fail_test "got $count JOIN[s] syn tx bind error expected $bind"
+	fi
+
+	count=$(mptcp_lib_get_counter ${ns2} "MPTcpExtMPJoinSynTxConnectErr")
+	if [ -z "$count" ]; then
+		rc=${KSFT_SKIP}
+	elif [ "$count" != "$connect" ]; then
+		rc=${KSFT_FAIL}
+		print_check "syn tx connect error"
+		fail_test "got $count JOIN[s] syn tx connect error expected $connect"
+	fi
+
+	print_results "join Tx" ${rc}
+}
+
 chk_join_nr()
 {
 	local syn_nr=$1
@@ -1390,6 +1442,9 @@ chk_join_nr()
 
 	print_results "join Rx" ${rc}
 
+	join_syn_tx="${join_syn_tx:-${syn_nr}}" \
+		chk_join_tx_nr
+
 	if $validate_checksum; then
 		chk_csum_nr $csum_ns1 $csum_ns2
 		chk_fail_nr $fail_nr $fail_nr
@@ -1930,8 +1985,10 @@ subflows_error_tests()
 		pm_nl_set_limits $ns1 0 1
 		pm_nl_set_limits $ns2 0 1
 		pm_nl_add_endpoint $ns2 10.0.1.2 flags subflow
+		pm_nl_add_endpoint $ns2 10.0.12.2 flags subflow
 		speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_bind_err=1 \
 			chk_join_nr 0 0 0
 	fi
 
@@ -1944,6 +2001,7 @@ subflows_error_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 flags subflow
 		speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 	fi
 
@@ -1956,6 +2014,7 @@ subflows_error_tests()
 		pm_nl_add_endpoint $ns2 10.0.2.2 flags subflow
 		speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 	fi
 
@@ -1977,6 +2036,7 @@ subflows_error_tests()
 
 		# additional subflow could be created only if the PM select
 		# the later endpoint, skipping the already used one
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 	fi
 }
@@ -2063,6 +2123,7 @@ signal_address_tests()
 		pm_nl_add_endpoint $ns1 10.0.14.1 flags signal
 		pm_nl_set_limits $ns2 3 3
 		run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=3 \
 			chk_join_nr 1 1 1
 		chk_add_nr 3 3
 	fi
@@ -2231,6 +2292,7 @@ add_addr_timeout_tests()
 		pm_nl_set_limits $ns2 2 2
 		speed=10 \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 \
 			chk_join_nr 1 1 1
 		chk_add_nr 8 0
 	fi
@@ -2331,6 +2393,7 @@ remove_tests()
 		pm_nl_set_limits $ns2 2 2
 		addr_nr_ns1=-3 speed=10 \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=2 join_connect_err=1 \
 			chk_join_nr 1 1 1
 		chk_add_nr 3 3
 		chk_rm_nr 3 1 invert
@@ -2396,6 +2459,7 @@ remove_tests()
 		pm_nl_set_limits $ns2 3 3
 		addr_nr_ns1=-8 speed=slow \
 			run_tests $ns1 $ns2 10.0.1.1
+		join_syn_tx=3 \
 			chk_join_nr 1 1 1
 		chk_add_nr 3 3
 		chk_rm_nr 3 1 invert
@@ -3703,6 +3767,7 @@ endpoint_tests()
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_ESTABLISHED 6
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_CLOSED 5 # one has been closed before estab
 
+		join_syn_tx=7 \
 			chk_join_nr 6 6 6
 		chk_rm_nr 4 4
 	fi
@@ -3775,6 +3840,7 @@ endpoint_tests()
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_ESTABLISHED 5
 		chk_evt_nr ns2 MPTCP_LIB_EVENT_SUB_CLOSED 3
 
+		join_connect_err=1 \
 			chk_join_nr 5 5 5
 		chk_add_nr 6 6
 		chk_rm_nr 4 3 invert
@@ -3806,6 +3872,7 @@ endpoint_tests()
 		wait_mpj $ns2
 		mptcp_lib_kill_wait $tests_pid
 
+		join_syn_tx=3 join_connect_err=1 \
 			chk_join_nr 2 2 2
 		chk_add_nr 2 2
 		chk_rm_nr 1 0 invert