ipv6: Change skb->data before using icmpv6_notify() to propagate redirect

In function ndisc_redirect_rcv(), the skb->data points to the transport
header, but function icmpv6_notify() need the skb->data points to the
inner IP packet. So before using icmpv6_notify() to propagate redirect,
change skb->data to point the inner IP packet that triggered the sending
of the Redirect, and introduce struct rd_msg to make it easy.

Signed-off-by: Duan Jiong <djduanjiong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 7af1ea8..23b3a7c 100644 (file)
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -78,6 +78,13 @@ struct ra_msg {
        __be32                  retrans_timer;
 };
 
+struct rd_msg {
+       struct icmp6hdr icmph;
+       struct in6_addr target;
+       struct in6_addr dest;
+       __u8            opt[0];
+};
+
 struct nd_opt_hdr {
        __u8            nd_opt_type;
        __u8            nd_opt_len;

diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f2a007b..6574175 100644 (file)
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1314,6 +1314,12 @@ out:
 
 static void ndisc_redirect_rcv(struct sk_buff *skb)
 {
+       u8 *hdr;
+       struct ndisc_options ndopts;
+       struct rd_msg *msg = (struct rd_msg *)skb_transport_header(skb);
+       u32 ndoptlen = skb->tail - (skb->transport_header +
+                                   offsetof(struct rd_msg, opt));
+
 #ifdef CONFIG_IPV6_NDISC_NODETYPE
        switch (skb->ndisc_nodetype) {
        case NDISC_NODETYPE_HOST:
@@ -1330,6 +1336,17 @@ static void ndisc_redirect_rcv(struct sk_buff *skb)
                return;
        }
 
+       if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts))
+               return;
+
+       if (!ndopts.nd_opts_rh)
+               return;
+
+       hdr = (u8 *)ndopts.nd_opts_rh;
+       hdr += 8;
+       if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
+               return;
+
        icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
 }