pfctl: restore '-Tload -f pf.conf' functionality

Allow only tables to be loaded from a file, rather than everything (i.e.
including options, rules).

Add a test case for this.

PR:		291318
MFC after:	1 week
Sponsored by:	Rubicon Communications, LLC ("Netgate")

sbin/pfctl/pfctl.c

@@ -3406,7 +3406,8 @@ main(int argc, char *argv[])
 	if ((opts & PF_OPT_NODNS) && (opts & PF_OPT_USEDNS))
 		errx(1, "-N and -r are mutually exclusive");
 
-	if ((tblcmdopt == NULL) ^ (tableopt == NULL))
+	if ((tblcmdopt == NULL) ^ (tableopt == NULL) &&
+	    (tblcmdopt == NULL || *tblcmdopt != 'l'))
 		usage();
 
 	if (tblcmdopt != NULL) {

tests/sys/netpfil/pf/table.sh

@@ -808,6 +808,40 @@ replace_cleanup()
 	pft_cleanup
 }
 
+atf_test_case "load" "cleanup"
+load_head()
+{
+	atf_set descr 'Test pfctl -T load (PR 291318)'
+	atf_set require.user root
+}
+
+load_body()
+{
+	pft_init
+
+	epair_send=$(vnet_mkepair)
+	ifconfig ${epair_send}a 192.0.2.1/24 up
+
+	vnet_mkjail alcatraz ${epair_send}b
+	jexec alcatraz ifconfig ${epair_send}b 192.0.2.2/24 up
+	jexec alcatraz pfctl -e
+
+	echo -e "table <private> persist { 172.16/12 }\nblock\npass in from <private>\n" \
+	    | atf_check -s exit:0 jexec alcatraz pfctl -Tload -f -
+
+	atf_check -s exit:0 -o ignore ping -c 3 192.0.2.2
+
+	atf_check -s exit:0 -o not-match:"block" \
+	    jexec alcatraz pfctl -sr
+	atf_check -s exit:0 -o match:'172.16.0.0/12' \
+	    jexec alcatraz pfctl -Tshow -t private
+}
+
+load_cleanup()
+{
+	pft_cleanup
+}
+
 atf_init_test_cases()
 {
 	atf_add_test_case "v4_counters"
@@ -827,4 +861,5 @@ atf_init_test_cases()
 	atf_add_test_case "show_recursive"
 	atf_add_test_case "in_anchor"
 	atf_add_test_case "replace"
+	atf_add_test_case "load"
 }