src: deduplicate find_proto function

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

1 files changed, 37 insertions, 0 deletions

diff --git a/xshared.c b/xshared.c
index 21b5b2cb..40b6b560 100644
--- a/xshared.c
+++ b/xshared.c
@@ -1,3 +1,5 @@
+#include <netdb.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <xtables.h>
 #include "xshared.h"
@@ -29,3 +31,38 @@ void print_extension_helps(const struct xtables_target *t,
 			m->match->help();
 	}
 }
+
+const char *
+proto_to_name(uint8_t proto, int nolookup)
+{
+	unsigned int i;
+
+	if (proto && !nolookup) {
+		struct protoent *pent = getprotobynumber(proto);
+		if (pent)
+			return pent->p_name;
+	}
+
+	for (i = 0; xtables_chain_protos[i].name != NULL; ++i)
+		if (xtables_chain_protos[i].num == proto)
+			return xtables_chain_protos[i].name;
+
+	return NULL;
+}
+
+struct xtables_match *
+find_proto(const char *pname, enum xtables_tryload tryload,
+	   int nolookup, struct xtables_rule_match **matches)
+{
+	unsigned int proto;
+
+	if (xtables_strtoui(pname, NULL, &proto, 0, UINT8_MAX)) {
+		const char *protoname = proto_to_name(proto, nolookup);
+
+		if (protoname)
+			return xtables_find_match(protoname, tryload, matches);
+	} else
+		return xtables_find_match(pname, tryload, matches);
+
+	return NULL;
+}