fib: allow to check if route exists in maps

f686a17eafa0 ("fib: Support existence check") adds EXPR_F_BOOLEAN as a
workaround to infer from the rhs of the relational expression if the fib
lookup wants to check for a specific output interface or, instead,
simply check for existence. This, however, does not work with maps.

The NFT_FIB_F_PRESENT flag can be used both with NFT_FIB_RESULT_OIF and
NFT_FIB_RESULT_OFINAME, my understanding is that they serve the same
purpose which is to check if a route exists, so they are redundant.

Add a 'check' fib result to check for routes while still keeping the
inference workaround for backward compatibility, but prefer the new
syntax in the listing.

Update man nft(8) and tests/py.

Fixes: f686a17eafa0 ("fib: Support existence check")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/tests/shell/testcases/parsing/large_rule_pipe b/tests/shell/testcases/parsing/large_rule_pipe
index b6760c01..4c4d62d2 100755
--- a/tests/shell/testcases/parsing/large_rule_pipe
+++ b/tests/shell/testcases/parsing/large_rule_pipe
@@ -246,7 +246,7 @@ table inet firewalld {
 	chain raw_PREROUTING {
 		type filter hook prerouting priority -290; policy accept;
 		icmpv6 type { nd-router-advert, nd-neighbor-solicit } accept
-		meta nfproto ipv6 fib saddr . iif oif missing drop
+		meta nfproto ipv6 fib saddr . iif check missing drop
 		jump raw_PREROUTING_ZONES_SOURCE
 		jump raw_PREROUTING_ZONES
 	}