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

PATCH In review Duan Jiong 2 participants 2 messages Dec 14, 2012

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Networking Network drivers IPv4/IPv6
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Duan Jiong

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#0 lore raw

PATCH v3 1/1 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 <[email protected]>
---
 include/net/ndisc.h |    7 +++++++
 net/ipv6/ndisc.c    |   17 +++++++++++++++++
 2 files changed, 24 insertions(+), 0 deletions(-)
include/net/ndisc.h +7 -0
index 980d263..6b305d7 100644
@@ -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;
net/ipv6/ndisc.c +17 -0
index 2edce30..89dab79 100644
@@ -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);
 }
Signature · 1 line
1.7.1
maintainer
#1 lore raw

From: Duan Jiong <[email protected]>
Date: Fri, 14 Dec 2012 20:59:59 +0800

Quoted 8 lines

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 <[email protected]>

Applied and queued up for -stable.