From 3c8c639c2a8863260b171c1a99b7a7286030b42c Mon Sep 17 00:00:00 2001
From: Ralf Baechle <ralf@linux-mips.org>
Date: Tue, 1 Aug 2017 11:50:34 +0200
Subject: rip98d: Replace naive mask2bits and bits2mask implementations.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 tcpip/rip98d.c | 57 +++++++--------------------------------------------------
 tcpip/rip98r.c |  6 +++---
 2 files changed, 10 insertions(+), 53 deletions(-)

(limited to 'tcpip')

diff --git a/tcpip/rip98d.c b/tcpip/rip98d.c
index f98be6f..43d31ba 100644
--- a/tcpip/rip98d.c
+++ b/tcpip/rip98d.c
@@ -39,45 +39,6 @@ int logging          = FALSE;
 
 struct route_struct *first_route;
 
-static struct mask_struct {
-	unsigned long int mask;
-	unsigned int bits;
-} mask_table[] = {
-	{0xFFFFFFFF, 32},
-	{0xFFFFFFFE, 31},
-	{0xFFFFFFFC, 30},
-	{0xFFFFFFF8, 29},
-	{0xFFFFFFF0, 28},
-	{0xFFFFFFE0, 27},
-	{0xFFFFFFC0, 26},
-	{0xFFFFFF80, 25},
-	{0xFFFFFF00, 24},
-	{0xFFFFFE00, 23},
-	{0xFFFFFC00, 22},
-	{0xFFFFF800, 21},
-	{0xFFFFF000, 20},
-	{0xFFFFE000, 19},
-	{0xFFFFC000, 18},
-	{0xFFFF8000, 17},
-	{0xFFFF0000, 16},
-	{0xFFFE0000, 15},
-	{0xFFFC0000, 14},
-	{0xFFF80000, 13},
-	{0xFFF00000, 12},
-	{0xFFE00000, 11},
-	{0xFFC00000, 10},
-	{0xFF800000,  9},
-	{0xFF000000,  8},
-	{0xFE000000,  7},
-	{0xFC000000,  6},
-	{0xF8000000,  5},
-	{0xF0000000,  4},
-	{0xE0000000,  3},
-	{0xC0000000,  2},
-	{0x80000000,  1},
-	{0x00000000,  0},
-};
-
 static void terminate(int sig)
 {
 	if (logging) {
@@ -90,24 +51,20 @@ static void terminate(int sig)
 
 unsigned int mask2bits(unsigned int mask)
 {
-	struct mask_struct *t;
+	mask = ~mask;
 
-	for (t = mask_table; t->mask != 0; t++)
-		if (mask == t->mask)
-			return t->bits;
+	if (!mask)
+		return 32;
 
-	return 0;
+	return __builtin_clz(mask);
 }
 
 unsigned int bits2mask(unsigned int bits)
 {
-	struct mask_struct *t;
-
-	for (t = mask_table; t->mask != 0; t++)
-		if (bits == t->bits)
-			return htonl(t->mask);
+	if (!bits)
+		return 0;
 
-	return 0;
+	return ~0 << (sizeof(unsigned int) * 8 - bits);
 }
 
 static unsigned long int hex2intrev(char *buffer)
diff --git a/tcpip/rip98r.c b/tcpip/rip98r.c
index 57afe4e..8332944 100644
--- a/tcpip/rip98r.c
+++ b/tcpip/rip98r.c
@@ -26,8 +26,8 @@ static int cmp_route(struct route_struct *route, struct in_addr addr, int bits,
 	unsigned long int old_mask, new_mask;
 	unsigned long int old_addr, new_addr;
 
-	old_mask = ntohl(bits2mask(route->bits));
-	new_mask = ntohl(bits2mask(bits));
+	old_mask = bits2mask(route->bits);
+	new_mask = bits2mask(bits);
 
 	old_addr = route->addr.s_addr;
 	new_addr = addr.s_addr;
@@ -234,7 +234,7 @@ void receive_routes(int s)
 			if (route->bits == 32) {
 				rt.rt_flags |= RTF_HOST;
 			} else {
-				netmask = bits2mask(route->bits);
+				netmask = htonl(bits2mask(route->bits));
 
 				trg.sin_family = AF_INET;
 				memcpy((char *)&trg.sin_addr, (char *)&netmask, sizeof(struct in_addr));
-- 
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