From adc559b69fc2b8d95a7c3bae96ca12faa0ba5d1d Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Tue, 17 Nov 2020 00:57:10 +0100
Subject: [PATCH] Use proto_to_name() from xshared in more places

Share the common proto name lookup code. While being at it, make proto
number variable 16bit, values may exceed 256.

This aligns iptables-nft '-p' argument printing with legacy iptables. In
practice, this should make a difference only in corner cases.

Signed-off-by: Phil Sutter <phil@nwl.cc>
(cherry picked from commit 556f704458cdb509d395ddb7d2629987d60e762e)
---
 include/xtables.h     |  2 +-
 iptables/ip6tables.c  | 22 +++++-----------------
 iptables/iptables.c   | 20 +++++---------------
 iptables/nft-shared.c |  6 +++---
 iptables/xshared.c    |  2 +-
 iptables/xshared.h    |  2 +-
 6 files changed, 16 insertions(+), 38 deletions(-)

diff --git a/include/xtables.h b/include/xtables.h
index 5044dd08e86d3..a7b36979398ba 100644
--- a/include/xtables.h
+++ b/include/xtables.h
@@ -395,7 +395,7 @@ struct xtables_rule_match {
  */
 struct xtables_pprot {
 	const char *name;
-	uint8_t num;
+	uint16_t num;
 };
 
 enum xtables_tryload {
diff --git a/iptables/ip6tables.c b/iptables/ip6tables.c
index c95355b091568..ce01ce8c04af6 100644
--- a/iptables/ip6tables.c
+++ b/iptables/ip6tables.c
@@ -796,28 +796,16 @@ print_iface(char letter, const char *iface, const unsigned char *mask,
 	}
 }
 
-/* The ip6tables looks up the /etc/protocols. */
 static void print_proto(uint16_t proto, int invert)
 {
 	if (proto) {
-		unsigned int i;
+		const char *pname = proto_to_name(proto, 0);
 		const char *invertstr = invert ? " !" : "";
 
-		const struct protoent *pent = getprotobynumber(proto);
-		if (pent) {
-			printf("%s -p %s",
-			       invertstr, pent->p_name);
-			return;
-		}
-
-		for (i = 0; xtables_chain_protos[i].name != NULL; ++i)
-			if (xtables_chain_protos[i].num == proto) {
-				printf("%s -p %s",
-				       invertstr, xtables_chain_protos[i].name);
-				return;
-			}
-
-		printf("%s -p %u", invertstr, proto);
+		if (pname)
+			printf("%s -p %s", invertstr, pname);
+		else
+			printf("%s -p %u", invertstr, proto);
 	}
 }
 
diff --git a/iptables/iptables.c b/iptables/iptables.c
index 7d6183116d265..514238d924780 100644
--- a/iptables/iptables.c
+++ b/iptables/iptables.c
@@ -764,23 +764,13 @@ list_entries(const xt_chainlabel chain, int rulenum, int verbose, int numeric,
 static void print_proto(uint16_t proto, int invert)
 {
 	if (proto) {
-		unsigned int i;
+		const char *pname = proto_to_name(proto, 0);
 		const char *invertstr = invert ? " !" : "";
 
-		const struct protoent *pent = getprotobynumber(proto);
-		if (pent) {
-			printf("%s -p %s", invertstr, pent->p_name);
-			return;
-		}
-
-		for (i = 0; xtables_chain_protos[i].name != NULL; ++i)
-			if (xtables_chain_protos[i].num == proto) {
-				printf("%s -p %s",
-				       invertstr, xtables_chain_protos[i].name);
-				return;
-			}
-
-		printf("%s -p %u", invertstr, proto);
+		if (pname)
+			printf("%s -p %s", invertstr, pname);
+		else
+			printf("%s -p %u", invertstr, proto);
 	}
 }
 
diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c
index c1664b50f9383..4253b08196d29 100644
--- a/iptables/nft-shared.c
+++ b/iptables/nft-shared.c
@@ -826,13 +826,13 @@ void save_rule_details(const struct iptables_command_state *cs,
 	}
 
 	if (proto > 0) {
-		const struct protoent *pent = getprotobynumber(proto);
+		const char *pname = proto_to_name(proto, 0);
 
 		if (invflags & XT_INV_PROTO)
 			printf("! ");
 
-		if (pent)
-			printf("-p %s ", pent->p_name);
+		if (pname)
+			printf("-p %s ", pname);
 		else
 			printf("-p %u ", proto);
 	}
diff --git a/iptables/xshared.c b/iptables/xshared.c
index 3bcf24735c8fb..9a17a8fdf11cd 100644
--- a/iptables/xshared.c
+++ b/iptables/xshared.c
@@ -48,7 +48,7 @@ void print_extension_helps(const struct xtables_target *t,
 }
 
 const char *
-proto_to_name(uint8_t proto, int nolookup)
+proto_to_name(uint16_t proto, int nolookup)
 {
 	unsigned int i;
 
diff --git a/iptables/xshared.h b/iptables/xshared.h
index 1e86aba8b2375..7c881c56a25da 100644
--- a/iptables/xshared.h
+++ b/iptables/xshared.h
@@ -152,7 +152,7 @@ enum {
 
 extern void print_extension_helps(const struct xtables_target *,
 	const struct xtables_rule_match *);
-extern const char *proto_to_name(uint8_t, int);
+extern const char *proto_to_name(uint16_t, int);
 extern int command_default(struct iptables_command_state *,
 	struct xtables_globals *);
 extern struct xtables_match *load_proto(struct iptables_command_state *);
-- 
2.40.0