[LTP] [PATCH] netstress: set port dynamically on the server-side

[Alexey Kodanev]

This simplifies tst_netload setup because previously the script had to:
  * Find an available port on the remote machine
  * Start the server with this port on a remote machine. Moreover, the port
    might not be available at the time it is started.
  * Wait for the server to bind and be in the listen state

With this patch, tst_netload has to:
  * Start the server. When the server completes its setup (after bind())
    it goes to background and tst_netload goes to the next step.
  * read a file with the server port

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
---
 testcases/lib/test_net.sh               |   38 +++++---------------------
 testcases/network/netstress/netstress.c |   44 ++++++++++++++++++++++++++++--
 2 files changed, 49 insertions(+), 33 deletions(-)

diff --git a/testcases/lib/test_net.sh b/testcases/lib/test_net.sh
index 1e001f7..95e13ee 100644
--- a/testcases/lib/test_net.sh
+++ b/testcases/lib/test_net.sh
@@ -392,7 +392,7 @@ tst_wait_ipv6_dad()
 
 tst_dump_rhost_cmd()
 {
-	tst_rhost_run -c "cat $TST_TMPDIR/bg.cmd"
+	tst_rhost_run -c "cat $TST_TMPDIR/netstress.log"
 }
 
 # Run network load test, see 'netstress -h' for option description
@@ -447,39 +447,17 @@ tst_netload()
 	local expect_ret=0
 	[ "$expect_res" != "pass" ] && expect_ret=1
 
-	local ptype="stream"
-	[ "$type" = "udp" ] && ptype="dgram"
-
-	local port=$(tst_rhost_run -c "tst_get_unused_port ipv6 $ptype")
-	[ $? -ne 0 ] && tst_brkm TBROK "failed to get unused port"
-
 	tst_rhost_run -c "pkill -9 netstress\$"
-
-	c_opts="${cs_opts}${c_opts}-a $c_num -r $c_requests -d $rfile -g $port"
-	s_opts="${cs_opts}${s_opts}-R $s_replies -g $port"
-
+	s_opts="${cs_opts}${s_opts}-R $s_replies -B $TST_TMPDIR"
 	tst_resm TINFO "run server 'netstress $s_opts'"
-	tst_rhost_run -s -B -c "netstress $s_opts"
-
-	tst_resm TINFO "check that server port in 'LISTEN' state"
-	local sec_waited=
-
-	local sock_cmd=
-	if [ "$type" = "sctp" ]; then
-		sock_cmd="netstat -naS | grep $port | grep -q LISTEN"
-	else
-		sock_cmd="ss -ln$(echo $type | head -c1) | grep -q $port"
+	tst_rhost_run -c "netstress $s_opts" > tst_netload.log 2>&1
+	if [ $? -ne 0 ]; then
+		cat tst_netload.log
+		tst_brkm TFAIL "server failed"
 	fi
 
-	for sec_waited in $(seq 1 1200); do
-		tst_rhost_run -c "$sock_cmd" && break
-		if [ $sec_waited -eq 1200 ]; then
-			tst_dump_rhost_cmd
-			tst_rhost_run -c "ss -dutnp | grep $port"
-			tst_brkm TFAIL "server not in LISTEN state"
-		fi
-		tst_sleep 100ms
-	done
+	local port=$(tst_rhost_run -s -c "cat $TST_TMPDIR/netstress_port")
+	c_opts="${cs_opts}${c_opts}-a $c_num -r $c_requests -d $rfile -g $port"
 
 	tst_resm TINFO "run client 'netstress -l $c_opts'"
 	netstress -l $c_opts > tst_netload.log 2>&1 || ret=1
diff --git a/testcases/network/netstress/netstress.c b/testcases/network/netstress/netstress.c
index 64fdc91..0a73321 100644
--- a/testcases/network/netstress/netstress.c
+++ b/testcases/network/netstress/netstress.c
@@ -83,9 +83,10 @@ static int max_rand_msg_len;
 static int server_max_requests	= 3;
 static int client_max_requests	= 10;
 static int clients_num;
-static char *tcp_port		= "61000";
+static char *tcp_port;
 static char *server_addr	= "localhost";
 static char *source_addr;
+static char *server_bg;
 static int busy_poll		= -1;
 static int max_etime_cnt = 12; /* ~30 sec max timeout if no connection */
 
@@ -112,6 +113,8 @@ static int wait_timeout = 60000;
 
 /* in the end test will save time result in this file */
 static char *rpath = "tfo_result";
+static char *port_path = "netstress_port";
+static char *log_path = "netstress.log";
 
 static char *narg, *Narg, *qarg, *rarg, *Rarg, *aarg, *Targ, *barg, *targ,
 	    *Aarg;
@@ -644,6 +647,9 @@ static void server_init(void)
 	hints.ai_socktype = sock_type;
 	hints.ai_flags = AI_PASSIVE;
 
+	if (!source_addr && !tcp_port)
+		tcp_port = "0";
+
 	if (source_addr && !strchr(source_addr, ':'))
 		SAFE_ASPRINTF(&src_addr, "::ffff:%s", source_addr);
 	setup_addrinfo(src_addr ? src_addr : source_addr, tcp_port,
@@ -659,6 +665,14 @@ static void server_init(void)
 
 	freeaddrinfo(local_addrinfo);
 
+	int port = TST_GETSOCKPORT(sfd);
+
+	tst_res(TINFO, "bind to port %d", port);
+	if (server_bg) {
+		SAFE_CHDIR(server_bg);
+		SAFE_FILE_PRINTF(port_path, "%d", port);
+	}
+
 	if (sock_type == SOCK_DGRAM)
 		return;
 
@@ -674,8 +688,7 @@ static void server_init(void)
 
 	SAFE_LISTEN(sfd, max_queue_len);
 
-	tst_res(TINFO, "Listen on the socket '%d', port '%s'", sfd, tcp_port);
-
+	tst_res(TINFO, "Listen on the socket '%d'", sfd);
 }
 
 static void server_cleanup(void)
@@ -683,8 +696,28 @@ static void server_cleanup(void)
 	SAFE_CLOSE(sfd);
 }
 
+static void move_to_background(void)
+{
+	if (SAFE_FORK())
+		exit(0);
+
+	SAFE_SETSID();
+
+	close(0);
+	SAFE_OPEN("/dev/null", O_RDONLY);
+
+	close(1);
+	close(2);
+	int fd = SAFE_OPEN(log_path, O_CREAT | O_TRUNC | O_RDONLY, 00444);
+
+	SAFE_DUP(fd);
+}
+
 static void server_run_udp(void)
 {
+	if (server_bg)
+		move_to_background();
+
 	pthread_t p_id = server_thread_add(sfd);
 
 	SAFE_PTHREAD_JOIN(p_id, NULL);
@@ -692,6 +725,9 @@ static void server_run_udp(void)
 
 static void server_run(void)
 {
+	if (server_bg)
+		move_to_background();
+
 	/* IPv4 source address will be mapped to IPv6 address */
 	struct sockaddr_in6 addr6;
 	socklen_t addr_size = sizeof(addr6);
@@ -946,11 +982,13 @@ static struct tst_option options[] = {
 
 	{"R:", &Rarg, "Server:\n-R x     x requests after which conn.closed"},
 	{"q:", &qarg, "-q x     x - TFO queue"},
+	{"B:", &server_bg, "-B x     run in background, x - process directory"},
 	{NULL, NULL, NULL}
 };
 
 static struct tst_test test = {
 	.test_all = do_test,
+	.forks_child = 1,
 	.setup = setup,
 	.cleanup = cleanup,
 	.options = options
-- 
1.7.1