selftests: mptcp: connect: use += operator to append strings

This patch uses addition assignment operator (+=) to append strings in
mptcp_connect.sh.

For extra_args, use += instead of open-coding to make the statements
shorter.

Add a local variable extra in do_transfer to save the various extra warning
logs, using += to append it. And add a new variable tc_info to save various
tc info, also using += to append it. This can make the code more readable
and prepare for the next commit.

Signed-off-by: Geliang Tang <[email protected]>

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

@@ -324,15 +324,15 @@ do_transfer()
 	port=$((port_base++))
 
 	if [ "$rcvbuf" -gt 0 ]; then
-		extra_args="$extra_args -R $rcvbuf"
+		extra_args+=" -R $rcvbuf"
 	fi
 
 	if [ "$sndbuf" -gt 0 ]; then
-		extra_args="$extra_args -S $sndbuf"
+		extra_args+=" -S $sndbuf"
 	fi
 
 	if [ -n "$testmode" ]; then
-		extra_args="$extra_args -m $testmode"
+		extra_args+=" -m $testmode"
 	fi
 
 	if [ -n "$extra_args" ] && $options_log; then
@@ -508,39 +508,43 @@ do_transfer()
 		fi
 	fi
 
-	if [ $retc -eq 0 ] && [ $rets -eq 0 ]; then
-		printf "[ OK ]"
-		mptcp_lib_result_pass "${TEST_GROUP}: ${result_msg}"
-	else
-		mptcp_lib_result_fail "${TEST_GROUP}: ${result_msg}"
-	fi
+	local extra=""
 
 	if [ $cookies -eq 2 ];then
 		if [ $stat_cookietx_last -ge $stat_cookietx_now ] ;then
-			printf " WARN: CookieSent: did not advance"
+			extra+=" WARN: CookieSent: did not advance"
 		fi
 		if [ $stat_cookierx_last -ge $stat_cookierx_now ] ;then
-			printf " WARN: CookieRecv: did not advance"
+			extra+=" WARN: CookieRecv: did not advance"
 		fi
 	else
 		if [ $stat_cookietx_last -ne $stat_cookietx_now ] ;then
-			printf " WARN: CookieSent: changed"
+			extra+=" WARN: CookieSent: changed"
 		fi
 		if [ $stat_cookierx_last -ne $stat_cookierx_now ] ;then
-			printf " WARN: CookieRecv: changed"
+			extra+=" WARN: CookieRecv: changed"
 		fi
 	fi
 
 	if [ ${stat_synrx_now_l} -gt ${expect_synrx} ]; then
-		printf " WARN: SYNRX: expect %d, got %d (probably retransmissions)" \
-			"${expect_synrx}" "${stat_synrx_now_l}"
+		extra+=" WARN: SYNRX: expect ${expect_synrx},"
+		extra+=" got ${stat_synrx_now_l} (probably retransmissions)"
 	fi
 	if [ ${stat_ackrx_now_l} -gt ${expect_ackrx} ]; then
-		printf " WARN: ACKRX: expect %d, got %d (probably retransmissions)" \
-			"${expect_ackrx}" "${stat_ackrx_now_l}"
+		extra+=" WARN: ACKRX: expect ${expect_ackrx},"
+		extra+=" got ${stat_ackrx_now_l} (probably retransmissions)"
+	fi
+
+	if [ $retc -eq 0 ] && [ $rets -eq 0 ]; then
+		printf "[ OK ]${extra:1}\n"
+		mptcp_lib_result_pass "${TEST_GROUP}: ${result_msg}"
+	else
+		if [ -n "${extra}" ]; then
+			printf "${extra:1}\n"
+		fi
+		mptcp_lib_result_fail "${TEST_GROUP}: ${result_msg}"
 	fi
 
-	echo
 	cat "$capout"
 	[ $retc -eq 0 ] && [ $rets -eq 0 ]
 }
@@ -866,8 +870,8 @@ stop_if_error "Could not even run ping tests"
 echo "[ OK ]"
 
 [ -n "$tc_loss" ] && tc -net "$ns2" qdisc add dev ns2eth3 root netem loss random $tc_loss delay ${tc_delay}ms
-echo -n "INFO: Using loss of $tc_loss "
-test "$tc_delay" -gt 0 && echo -n "delay $tc_delay ms "
+tc_info="loss of $tc_loss "
+test "$tc_delay" -gt 0 && tc_info+="delay $tc_delay ms "
 
 reorder_delay=$((tc_delay / 4))
 
@@ -878,17 +882,17 @@ if [ -z "${tc_reorder}" ]; then
 
 	if [ $reorder_delay -gt 0 ] && [ $reorder1 -lt 100 ] && [ $reorder2 -gt 0 ]; then
 		tc_reorder="reorder ${reorder1}% ${reorder2}%"
-		echo -n "$tc_reorder with delay ${reorder_delay}ms "
+		tc_info+="$tc_reorder with delay ${reorder_delay}ms "
 	fi
 elif [ "$tc_reorder" = "0" ];then
 	tc_reorder=""
 elif [ "$reorder_delay" -gt 0 ];then
 	# reordering requires some delay
 	tc_reorder="reorder $tc_reorder"
-	echo -n "$tc_reorder with delay ${reorder_delay}ms "
+	tc_info+="$tc_reorder with delay ${reorder_delay}ms "
 fi
 
-echo "on ns3eth4"
+echo "INFO: Using ${tc_info}on ns3eth4"
 
 tc -net "$ns3" qdisc add dev ns3eth4 root netem delay ${reorder_delay}ms $tc_reorder