nftutils: add and use wrappers for getprotoby{name,number}_r(), getservbyport_r()

We should aim to use the thread-safe variants of getprotoby{name,number}
and getservbyport(). However, they may not be available with other libc,
so it requires a configure check. As that is cumbersome, add wrappers
that do that at one place.

These wrappers are thread-safe, if libc provides the reentrant versions.
Use them.

Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 4 insertions, 3 deletions

diff --git a/src/rule.c b/src/rule.c
index 99c4f0bb..b59fcd3a 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -27,6 +27,7 @@
 #include <cache.h>
 #include <owner.h>
 #include <intervals.h>
+#include "nftutils.h"
 
 #include <libnftnl/common.h>
 #include <libnftnl/ruleset.h>
@@ -1666,10 +1667,10 @@ struct obj *obj_lookup_fuzzy(const char *obj_name,
 
 static void print_proto_name_proto(uint8_t l4, struct output_ctx *octx)
 {
-	const struct protoent *p = getprotobynumber(l4);
+	char name[NFT_PROTONAME_MAXSIZE];
 
-	if (p)
-		nft_print(octx, "%s", p->p_name);
+	if (nft_getprotobynumber(l4, name, sizeof(name)))
+		nft_print(octx, "%s", name);
 	else
 		nft_print(octx, "%d", l4);
 }