From 1285f9a043e4ef9d99d8788315dc4398299bb8a8 Mon Sep 17 00:00:00 2001

From: Phil Sutter <phil@nwl.cc>

Date: Tue, 27 Apr 2021 10:02:34 +0200

Subject: [PATCH] nft-arp: Make use of ipv4_addr_to_string()

This eliminates quite a bit of redundant code apart from also dropping

use of obsolete function gethostbyaddr().

Signed-off-by: Phil Sutter <phil@nwl.cc>

(cherry picked from commit 1e984079817a3c804eae25dea937d63d18c57a6c)

---

 iptables/nft-arp.c | 99 ++++------------------------------------------

 iptables/xshared.c |  6 +--

 iptables/xshared.h |  3 ++

 3 files changed, 14 insertions(+), 94 deletions(-)

diff --git a/iptables/nft-arp.c b/iptables/nft-arp.c

index c82ffdc95e300..2a9387a18dffe 100644

--- a/iptables/nft-arp.c

+++ b/iptables/nft-arp.c

@@ -42,78 +42,6 @@ char *arp_opcodes[] =

 	"ARP_NAK",

 };

-static char *

-addr_to_dotted(const struct in_addr *addrp)

-{

-	static char buf[20];

-	const unsigned char *bytep;

-

-	bytep = (const unsigned char *) &(addrp->s_addr);

-	sprintf(buf, "%d.%d.%d.%d", bytep[0], bytep[1], bytep[2], bytep[3]);

-	return buf;

-}

-

-static char *

-addr_to_host(const struct in_addr *addr)

-{

-	struct hostent *host;

-

-	if ((host = gethostbyaddr((char *) addr,

-					sizeof(struct in_addr), AF_INET)) != NULL)

-		return (char *) host->h_name;

-

-	return (char *) NULL;

-}

-

-static char *

-addr_to_network(const struct in_addr *addr)

-{

-	struct netent *net;

-

-	if ((net = getnetbyaddr((long) ntohl(addr->s_addr), AF_INET)) != NULL)

-		return (char *) net->n_name;

-

-	return (char *) NULL;

-}

-

-static char *

-addr_to_anyname(const struct in_addr *addr)

-{

-	char *name;

-

-	if ((name = addr_to_host(addr)) != NULL ||

-		(name = addr_to_network(addr)) != NULL)

-		return name;

-

-	return addr_to_dotted(addr);

-}

-

-static char *

-mask_to_dotted(const struct in_addr *mask)

-{

-	int i;

-	static char buf[22];

-	u_int32_t maskaddr, bits;

-

-	maskaddr = ntohl(mask->s_addr);

-

-	if (maskaddr == 0xFFFFFFFFL)

-		/* we don't want to see "/32" */

-		return "";

-

-	i = 32;

-	bits = 0xFFFFFFFEL;

-	while (--i >= 0 && maskaddr != bits)

-		bits <<= 1;

-	if (i >= 0)

-		sprintf(buf, "/%d", i);

-	else

-		/* mask was not a decent combination of 1's and 0's */

-		snprintf(buf, sizeof(buf), "/%s", addr_to_dotted(mask));

-

-	return buf;

-}

-

 static bool need_devaddr(struct arpt_devaddr_info *info)

 {

 	int i;

@@ -403,7 +331,6 @@ static void nft_arp_print_rule_details(const struct iptables_command_state *cs,

 				       unsigned int format)

 {

 	const struct arpt_entry *fw = &cs->arp;

-	char buf[BUFSIZ];

 	char iface[IFNAMSIZ+2];

 	const char *sep = "";

 	int print_iface = 0;

@@ -450,15 +377,10 @@ static void nft_arp_print_rule_details(const struct iptables_command_state *cs,

 	}

 	if (fw->arp.smsk.s_addr != 0L) {

-		printf("%s%s", sep, fw->arp.invflags & IPT_INV_SRCIP

-			? "! " : "");

-		if (format & FMT_NUMERIC)

-			sprintf(buf, "%s", addr_to_dotted(&(fw->arp.src)));

-		else

-			sprintf(buf, "%s", addr_to_anyname(&(fw->arp.src)));

-		strncat(buf, mask_to_dotted(&(fw->arp.smsk)),

-			sizeof(buf) - strlen(buf) - 1);

-		printf("-s %s", buf);

+		printf("%s%s-s %s", sep,

+		       fw->arp.invflags & IPT_INV_SRCIP ? "! " : "",

+		       ipv4_addr_to_string(&fw->arp.src,

+					   &fw->arp.smsk, format));

 		sep = " ";

 	}

@@ -476,15 +398,10 @@ static void nft_arp_print_rule_details(const struct iptables_command_state *cs,

 after_devsrc:

 	if (fw->arp.tmsk.s_addr != 0L) {

-		printf("%s%s", sep, fw->arp.invflags & IPT_INV_DSTIP

-			? "! " : "");

-		if (format & FMT_NUMERIC)

-			sprintf(buf, "%s", addr_to_dotted(&(fw->arp.tgt)));

-		else

-			sprintf(buf, "%s", addr_to_anyname(&(fw->arp.tgt)));

-		strncat(buf, mask_to_dotted(&(fw->arp.tmsk)),

-			sizeof(buf) - strlen(buf) - 1);

-		printf("-d %s", buf);

+		printf("%s%s-d %s", sep,

+		       fw->arp.invflags & IPT_INV_DSTIP ? "! " : "",

+		       ipv4_addr_to_string(&fw->arp.tgt,

+					   &fw->arp.tmsk, format));

 		sep = " ";

 	}

diff --git a/iptables/xshared.c b/iptables/xshared.c

index 71f689901e1d4..9a1f465a5a6d3 100644

--- a/iptables/xshared.c

+++ b/iptables/xshared.c

@@ -550,9 +550,9 @@ void debug_print_argv(struct argv_store *store)

 }

 #endif

-static const char *ipv4_addr_to_string(const struct in_addr *addr,

-				       const struct in_addr *mask,

-				       unsigned int format)

+const char *ipv4_addr_to_string(const struct in_addr *addr,

+				const struct in_addr *mask,

+				unsigned int format)

 {

 	static char buf[BUFSIZ];

diff --git a/iptables/xshared.h b/iptables/xshared.h

index 9159b2b1f3768..1e86aba8b2375 100644

--- a/iptables/xshared.h

+++ b/iptables/xshared.h

@@ -206,6 +206,9 @@ void debug_print_argv(struct argv_store *store);

 #  define debug_print_argv(...) /* nothing */

 #endif

+const char *ipv4_addr_to_string(const struct in_addr *addr,

+				const struct in_addr *mask,

+				unsigned int format);

 void print_ipv4_addresses(const struct ipt_entry *fw, unsigned int format);

 void print_ipv6_addresses(const struct ip6t_entry *fw6, unsigned int format);

-- 

2.31.1