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/include/fib.h b/include/fib.h
index 67edccfe..07bb2210 100644
--- a/include/fib.h
+++ b/include/fib.h
@@ -3,7 +3,7 @@
 
 #include <linux/netfilter/nf_tables.h>
 
-extern const char *fib_result_str(enum nft_fib_result result);
+extern const char *fib_result_str(const struct expr *expr);
 extern struct expr *fib_expr_alloc(const struct location *loc,
 				   unsigned int flags,
 				   unsigned int result);