From: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Date: Fri, 11 Apr 2008 11:17:55 +0000 (+0900)
Subject: [IPV6]: Use XOR and OR rather than mutiple ands for ipv6 address comparisons.
X-Git-Tag: v2.6.26-rc1~1138^2~123^2~11
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fed85383ac34d82e96f227ce49ce68117cec23a0;p=linux-2.6

[IPV6]: Use XOR and OR rather than mutiple ands for ipv6 address comparisons.

ipv6_addr_equal(), ipv6_addr_v4mapped(),
ipv6_addr_is_ll_all_{nodes,routers}(),
ipv6_masked_addr_cmp()

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
---

diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index bdcc863a60..1dc9d03372 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -240,18 +240,16 @@ static inline int ipv6_addr_is_multicast(const struct in6_addr *addr)
 
 static inline int ipv6_addr_is_ll_all_nodes(const struct in6_addr *addr)
 {
-	return (addr->s6_addr32[0] == htonl(0xff020000) &&
-		addr->s6_addr32[1] == 0 &&
-		addr->s6_addr32[2] == 0 &&
-		addr->s6_addr32[3] == htonl(0x00000001));
+	return (((addr->s6_addr32[0] ^ htonl(0xff020000)) |
+		addr->s6_addr32[1] | addr->s6_addr32[2] |
+		(addr->s6_addr32[3] ^ htonl(0x00000001))) == 0);
 }
 
 static inline int ipv6_addr_is_ll_all_routers(const struct in6_addr *addr)
 {
-	return (addr->s6_addr32[0] == htonl(0xff020000) &&
-		addr->s6_addr32[1] == 0 &&
-		addr->s6_addr32[2] == 0 &&
-		addr->s6_addr32[3] == htonl(0x00000002));
+	return (((addr->s6_addr32[0] ^ htonl(0xff020000)) |
+		addr->s6_addr32[1] | addr->s6_addr32[2] |
+		(addr->s6_addr32[3] ^ htonl(0x00000002))) == 0);
 }
 
 static inline int ipv6_isatap_eui64(u8 *eui, __be32 addr)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 5738c1c73a..a0c285b631 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -280,12 +280,10 @@ static inline int
 ipv6_masked_addr_cmp(const struct in6_addr *a1, const struct in6_addr *m,
 		     const struct in6_addr *a2)
 {
-	unsigned int i;
-
-	for (i = 0; i < 4; i++)
-		if ((a1->s6_addr32[i] ^ a2->s6_addr32[i]) & m->s6_addr32[i])
-			return 1;
-	return 0;
+	return (!!(((a1->s6_addr32[0] ^ a2->s6_addr32[0]) & m->s6_addr32[0]) |
+		   ((a1->s6_addr32[1] ^ a2->s6_addr32[1]) & m->s6_addr32[1]) |
+		   ((a1->s6_addr32[2] ^ a2->s6_addr32[2]) & m->s6_addr32[2]) |
+		   ((a1->s6_addr32[3] ^ a2->s6_addr32[3]) & m->s6_addr32[3])));
 }
 
 static inline void ipv6_addr_copy(struct in6_addr *a1, const struct in6_addr *a2)
@@ -320,10 +318,10 @@ static inline void ipv6_addr_set(struct in6_addr *addr,
 static inline int ipv6_addr_equal(const struct in6_addr *a1,
 				  const struct in6_addr *a2)
 {
-	return (a1->s6_addr32[0] == a2->s6_addr32[0] &&
-		a1->s6_addr32[1] == a2->s6_addr32[1] &&
-		a1->s6_addr32[2] == a2->s6_addr32[2] &&
-		a1->s6_addr32[3] == a2->s6_addr32[3]);
+	return (((a1->s6_addr32[0] ^ a2->s6_addr32[0]) |
+		 (a1->s6_addr32[1] ^ a2->s6_addr32[1]) |
+		 (a1->s6_addr32[2] ^ a2->s6_addr32[2]) |
+		 (a1->s6_addr32[3] ^ a2->s6_addr32[3])) == 0);
 }
 
 static inline int __ipv6_prefix_equal(const __be32 *a1, const __be32 *a2,
@@ -371,8 +369,8 @@ static inline int ipv6_addr_any(const struct in6_addr *a)
 
 static inline int ipv6_addr_v4mapped(const struct in6_addr *a)
 {
-	return ((a->s6_addr32[0] | a->s6_addr32[1]) == 0 &&
-		 a->s6_addr32[2] == htonl(0x0000ffff));
+	return ((a->s6_addr32[0] | a->s6_addr32[1] |
+		 (a->s6_addr32[2] ^ htonl(0x0000ffff))) == 0);
 }
 
 /*