[PATCH v2] ipv6: Change skb->data before using icmpv6_notify() to propagate redirect
From: Duan Jiong <hidden>
Date: 2012-12-13 11:21:42
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
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. Many thanks to Steffen Klassert. Signed-off-by: Duan Jiong <redacted> --- include/net/ndisc.h | 7 +++++++ net/ipv6/ndisc.c | 22 ++++++++++++++++++++++ 2 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 980d263..6b305d7 100644
--- 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 2edce30..03deabc 100644
--- 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 +1355,22 @@ static void ndisc_redirect_rcv(struct sk_buff *skb) return; } + if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) { + ND_PRINTK(2, warn, + "Redirect: invalid ND options\n"); + 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); }
--
1.7.1