libpfctl: decode PFR_A_AF into a u8

The kernel sends PFR_A_AF as a u32, although it is documented and
parsed as a u8, and libpfctl decoded it with snl_attr_get_uint32()
straight into the u8 pfra_af.  That overwrote pfra_net, pfra_not and
pfra_fback, and left pfra_af zero on big-endian hosts.

Decode it via a temporary, and accept a u8 as well, so that the
kernel can be corrected later without breaking libpfctl.

Reviewed by:		kp
Approved by:		kp (mentor)
Fixes:			f27e44e2e3 ("pf: convert DIOCRGETADDRS to netlink")
Sponsored by:		Rubicon Communications, LLC ("Netgate")
Differential Revision:	https://reviews.freebsd.org/D60110

lib/libpfctl/libpfctl.c

@@ -2777,9 +2777,25 @@ struct nl_addrs {
 	size_t total_count;
 };
 
+/* pfra_af is a u8, but the kernel sends PFR_A_AF as a u32.  Accept both. */
+static bool
+snl_attr_get_pfra_af(struct snl_state *ss, struct nlattr *nla,
+    const void *arg __unused, void *target)
+{
+	uint32_t af;
+
+	if (snl_attr_get_uint8(ss, nla, NULL, target))
+		return (true);
+	if (! snl_attr_get_uint32(ss, nla, NULL, &af))
+		return (false);
+	*(uint8_t *)target = af;
+
+	return (true);
+}
+
 #define _OUT(_field)	offsetof(struct pfr_addr, _field)
 static const struct snl_attr_parser ap_pfr_addr[] = {
-	{ .type = PFR_A_AF, .off = _OUT(pfra_af), .cb = snl_attr_get_uint32 },
+	{ .type = PFR_A_AF, .off = _OUT(pfra_af), .cb = snl_attr_get_pfra_af },
 	{ .type = PFR_A_NET, .off = _OUT(pfra_net), .cb = snl_attr_get_uint8 },
 	{ .type = PFR_A_NOT, .off = _OUT(pfra_not), .cb = snl_attr_get_bool },
 	{ .type = PFR_A_ADDR, .off = _OUT(pfra_ip6addr), .cb = snl_attr_get_in6_addr },

sys/netpfil/pf/pf_nl.h

@@ -494,7 +494,7 @@ enum pf_tstats_t {
 
 enum pfr_addr_t {
 	PFR_A_UNSPEC,
-	PFR_A_AF		= 1, /* uint8_t */
+	PFR_A_AF		= 1, /* uint8_t, uint32_t in replies */
 	PFR_A_NET		= 2, /* uint8_t */
 	PFR_A_NOT		= 3, /* bool */
 	PFR_A_ADDR		= 4, /* in6_addr */