[ 086/123] ipv6: Change skb->data before using icmpv6_notify() to propagate redirect

Greg Kroah-Hartman
2013-01-09T21:02:09Z

From: Duan Jiong <djduanjiong@gmail.com>

[ Upstream commit 093d04d42fa094f6740bb188f0ad0c215ff61e2c ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/ndisc.h | 7 +++++++
net/ipv6/ndisc.c | 17 +++++++++++++++++
2 files changed, 24 insertions(+)

--- 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;
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1333,6 +1333,12 @@ 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:
@@ -1349,6 +1355,17 @@ static void ndisc_redirect_rcv(struct sk
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);
}