src: rt: add keyword distinction for nexthop vs nexthop6

the rt expression currently always sets NFT_RT_NEXTHOP4 and then
uses the network base to determine if its really supposed to be
NEXTHOP6.

For inet, this will fail because the network base is not known,
so this currently enforces need for "meta nfproto" to dermine the
type.

Allow following syntax instead:
  rt ip nexthop
  rt ip6 nexthop

There is no need for a dependency anymore, as rt expression
checks the hook protocol, ie. NEXTHOP4 will break if the hook pf
is not NFPROTO_IPV4.

Cc: Anders K. Pedersen <akp@cohaesio.com>
Signed-off-by: Florian Westphal <fw@strlen.de>

1 files changed, 23 insertions, 1 deletions

diff --git a/src/parser_bison.y b/src/parser_bison.y
index 0a74a7a5..f996d9d9 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -665,7 +665,7 @@ static void location_update(struct location *loc, struct location *rhs, int n)
 
 %type <expr>			rt_expr
 %destructor { expr_free($$); }	rt_expr
-%type <val>			rt_key
+%type <val>			rt_key_proto	rt_key
 
 %type <expr>			ct_expr
 %destructor { expr_free($$); }	ct_expr
@@ -3246,10 +3246,32 @@ hash_expr		:	JHASH		expr	MOD	NUM	SEED	NUM	offset_opt
 			}
 			;
 
+rt_key_proto		:	IP		{ $$ = NFPROTO_IPV4; }
+			|	IP6		{ $$ = NFPROTO_IPV6; }
+			;
+
 rt_expr			:	RT	rt_key
 			{
 				$$ = rt_expr_alloc(&@$, $2, true);
 			}
+			|	RT	rt_key_proto	rt_key
+			{
+				enum nft_rt_keys rtk = $3;
+
+				switch ($2) {
+				case NFPROTO_IPV4:
+					break;
+				case NFPROTO_IPV6:
+					if ($3 == NFT_RT_NEXTHOP4)
+						rtk = NFT_RT_NEXTHOP6;
+					break;
+				default:
+					YYERROR;
+					break;
+				}
+
+				$$ = rt_expr_alloc(&@$, rtk, false);
+			}
 			;
 
 rt_key			:	CLASSID		{ $$ = NFT_RT_CLASSID; }