pf tests: factor out common dummynet check

Reviewed by:	glebius
Sponsored by:	Rubicon Communications, LLC ("Netgate")
Differential Revision:	https://reviews.freebsd.org/D35160

tests/sys/netpfil/pf/ether.sh

@@ -326,11 +326,7 @@ captive_long_body()
 	# Host is client, jail 'gw' is the captive portal gateway, jail 'srv'
 	# is a random (web)server. We use the echo protocol rather than http
 	# for the test, because that's easier.
-	pft_init
-
-	if ! kldstat -q -m dummynet; then
-		atf_skip "This test requires dummynet"
-	fi
+	dummynet_init
 
 	epair_gw=$(vnet_mkepair)
 	epair_srv=$(vnet_mkepair)

tests/sys/netpfil/pf/match.sh

@@ -36,10 +36,7 @@ dummynet_head()
 
 dummynet_body()
 {
-	pft_init
-	if ! kldstat -q -m dummynet; then
-		atf_skip "This test requires dummynet"
-	fi
+	dummynet_init
 
 	epair=$(vnet_mkepair)
 	vnet_mkjail alcatraz ${epair}b

tests/sys/netpfil/pf/utils.subr

@@ -87,6 +87,15 @@ pflog_init()
 	fi
 }
 
+dummynet_init()
+{
+	pft_init
+
+	if ! kldstat -q -m dummynet; then
+		atf_skip "This test requires dummynet"
+	fi
+}
+
 pft_set_rules()
 {
 	jname=$1