[IPV6]: ipv6_addr_prefix() cleanup, eliminate duplication.

include/net/ipv6.h

@@ -263,6 +263,21 @@ static inline void ipv6_addr_copy(struct in6_addr *a1, const struct in6_addr *a2
 	memcpy((void *) a1, (const void *) a2, sizeof(struct in6_addr));
 }
 
+static inline void ipv6_addr_prefix(struct in6_addr *pfx, 
+				    const struct in6_addr *addr,
+				    int plen)
+{
+	/* caller must guarantee 0 <= plen <= 128 */
+	int o = plen >> 3,
+	    b = plen & 0x7;
+
+	memcpy(pfx->s6_addr, addr, o);
+	if (b != 0)
+		pfx->s6_addr[o] = addr->s6_addr[o] & (0xff00 >> b);
+	if (o < 16)
+		memset(pfx->s6_addr + o, 0, 16 - o);
+}
+
 #ifndef __HAVE_ARCH_ADDR_SET
 static inline void ipv6_addr_set(struct in6_addr *addr, 
 				     __u32 w1, __u32 w2,

net/ipv6/addrconf.c

@@ -400,38 +400,6 @@ static struct inet6_dev * ipv6_find_idev(struct net_device *dev)
 	return idev;
 }
 
-void ipv6_addr_prefix(struct in6_addr *prefix,
-	struct in6_addr *addr, int prefix_len)
-{
-	unsigned long mask;
-	int ncopy, nbits;
-
-	memset(prefix, 0, sizeof(*prefix));
-
-	if (prefix_len <= 0)
-		return;
-	if (prefix_len > 128)
-		prefix_len = 128;
-
-	ncopy = prefix_len / 32;
-	switch (ncopy) {
-	case 4:	prefix->s6_addr32[3] = addr->s6_addr32[3];
-	case 3:	prefix->s6_addr32[2] = addr->s6_addr32[2];
-	case 2:	prefix->s6_addr32[1] = addr->s6_addr32[1];
-	case 1:	prefix->s6_addr32[0] = addr->s6_addr32[0];
-	case 0:	break;
-	}
-	nbits = prefix_len % 32;
-	if (nbits == 0)
-		return;
-
-	mask = ~((1 << (32 - nbits)) - 1);
-	mask = htonl(mask);
-
-	prefix->s6_addr32[ncopy] = addr->s6_addr32[ncopy] & mask;
-}
-
-
 static void dev_forward_change(struct inet6_dev *idev)
 {
 	struct net_device *dev;

net/ipv6/route.c

@@ -587,19 +587,6 @@ static int ip6_dst_gc(void)
    Remove it only when all the things will work!
  */
 
-static void ipv6_addr_prefix(struct in6_addr *pfx,
-			     const struct in6_addr *addr, int plen)
-{
-	int b = plen&0x7;
-	int o = plen>>3;
-
-	memcpy(pfx->s6_addr, addr, o);
-	if (o < 16)
-		memset(pfx->s6_addr + o, 0, 16 - o);
-	if (b != 0)
-		pfx->s6_addr[o] = addr->s6_addr[o]&(0xff00 >> b);
-}
-
 static int ipv6_get_mtu(struct net_device *dev)
 {
 	int mtu = IPV6_MIN_MTU;