ipv6: Unshare ip6_nd_hdr() and change return type to void.

- move ip6_nd_hdr() to its users' source files.
  In net/ipv6/mcast.c, it will be called ip6_mc_hdr().
- make return type to void since this function never fails.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index 587a845..f25002a 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1313,6 +1313,31 @@
 	return scount;
 }
 
+static void ip6_mc_hdr(struct sock *sk, struct sk_buff *skb,
+		       struct net_device *dev,
+		       const struct in6_addr *saddr,
+		       const struct in6_addr *daddr,
+		       int proto, int len)
+{
+	struct ipv6hdr *hdr;
+
+	skb->protocol = htons(ETH_P_IPV6);
+	skb->dev = dev;
+
+	skb_reset_network_header(skb);
+	skb_put(skb, sizeof(struct ipv6hdr));
+	hdr = ipv6_hdr(skb);
+
+	ip6_flow_hdr(hdr, 0, 0);
+
+	hdr->payload_len = htons(len);
+	hdr->nexthdr = proto;
+	hdr->hop_limit = inet6_sk(sk)->hop_limit;
+
+	hdr->saddr = *saddr;
+	hdr->daddr = *daddr;
+}
+
 static struct sk_buff *mld_newpack(struct net_device *dev, int size)
 {
 	struct net *net = dev_net(dev);
@@ -1348,7 +1373,7 @@
 	} else
 		saddr = &addr_buf;
 
-	ip6_nd_hdr(sk, skb, dev, saddr, &mld2_all_mcr, NEXTHDR_HOP, 0);
+	ip6_mc_hdr(sk, skb, dev, saddr, &mld2_all_mcr, NEXTHDR_HOP, 0);
 
 	memcpy(skb_put(skb, sizeof(ra)), ra, sizeof(ra));
 
@@ -1740,7 +1765,7 @@
 	} else
 		saddr = &addr_buf;
 
-	ip6_nd_hdr(sk, skb, dev, saddr, snd_addr, NEXTHDR_HOP, payload_len);
+	ip6_mc_hdr(sk, skb, dev, saddr, snd_addr, NEXTHDR_HOP, payload_len);
 
 	memcpy(skb_put(skb, sizeof(ra)), ra, sizeof(ra));