[PATCH v3 08/25] fwd: Allow FWD_DUAL_STACK_ANY flag to be passed directly to fwd_rule_add()

[David Gibson <david@gibson.dropbear.id.au>]

fwd_rule_add() takes a flags parameter, but it only allows the FWD_WEAK
and FWD_SCAN flags to be specified there.  It doesn't allow the
FWD_DUAL_STACK_ANY flag to be set, instead expecting a [*] address to be
indicated by passing NULL as @addr.

However, for upcoming dynamic rule updates, it's more convenient to be able
to explicitly pass FWD_DUAL_STACK_ANY along with an address of ::.  Allow
that mode of calling.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 fwd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fwd.c b/fwd.c
index 3395a28e..d73b7ca7 100644
--- a/fwd.c
+++ b/fwd.c
@@ -362,18 +362,21 @@ void fwd_rule_add(struct fwd_table *fwd, uint8_t proto, uint8_t flags,
 		  in_port_t first, in_port_t last, in_port_t to)
 {
 	/* Flags which can be set from the caller */
-	const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN;
+	const uint8_t allowed_flags = FWD_WEAK | FWD_SCAN | FWD_DUAL_STACK_ANY;
 	unsigned num = (unsigned)last - first + 1;
 	struct fwd_rule *new;
 	unsigned i, port;
 
 	assert(!(flags & ~allowed_flags));
-
 	if (fwd->count >= ARRAY_SIZE(fwd->rules))
 		die("Too many port forwarding ranges");
 	if ((fwd->sock_count + num) > ARRAY_SIZE(fwd->socks))
 		die("Too many listening sockets");
 
+	/* Passing a non-wildcard address with DUAL_STACK_ANY  is a bug */
+	assert(!(flags & FWD_DUAL_STACK_ANY) || !addr ||
+	       inany_equals(addr, &inany_any6));
+
 	/* Check for any conflicting entries */
 	for (i = 0; i < fwd->count; i++) {
 		char newstr[INANY_ADDRSTRLEN], rulestr[INANY_ADDRSTRLEN];
-- 
2.53.0