ndisc: Introduce ndisc_fill_redirect_hdr_option().

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 6 deletions

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 539b2ec37d3a..53a545f32625 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1341,6 +1341,19 @@ static void ndisc_redirect_rcv(struct sk_buff *skb)
         icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
 }
 
+static u8 *ndisc_fill_redirect_hdr_option(u8 *opt, struct sk_buff *orig_skb,
+                                          int rd_len)
+{
+        memset(opt, 0, 8);
+        *(opt++) = ND_OPT_REDIRECT_HDR;
+        *(opt++) = (rd_len >> 3);
+        opt += 6;
+
+        memcpy(opt, ipv6_hdr(orig_skb), rd_len - 8);
+
+        return opt + rd_len - 8;
+}
+
 void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
 {
         struct net_device *dev = skb->dev;
@@ -1470,12 +1483,8 @@ void ndisc_send_redirect(struct sk_buff *skb, const struct in6_addr *target)
          *      build redirect option and copy skb over to the new packet.
          */
 
-        memset(opt, 0, 8);
-        *(opt++) = ND_OPT_REDIRECT_HDR;
-        *(opt++) = (rd_len >> 3);
-        opt += 6;
-
-        memcpy(opt, ipv6_hdr(skb), rd_len - 8);
+        if (rd_len)
+                opt = ndisc_fill_redirect_hdr_option(opt, skb, rd_len);
 
         msg->icmph.icmp6_cksum = csum_ipv6_magic(&saddr_buf, &ipv6_hdr(skb)->saddr,
                                                  len, IPPROTO_ICMPV6,