net: accept UFO datagrams from tuntap and packet

[uclinux-h8/linux.git] / net / ipv6 / output_core.c

diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index 4a7e5ff..4fe7c90 100644 (file)
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -31,6 +31,37 @@ static u32 __ipv6_select_ident(struct net *net, u32 hashrnd,
        return id;
 }
 
+/* This function exists only for tap drivers that must support broken
+ * clients requesting UFO without specifying an IPv6 fragment ID.
+ *
+ * This is similar to ipv6_select_ident() but we use an independent hash
+ * seed to limit information leakage.
+ *
+ * The network header must be set before calling this.
+ */
+__be32 ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
+{
+       static u32 ip6_proxy_idents_hashrnd __read_mostly;
+       struct in6_addr buf[2];
+       struct in6_addr *addrs;
+       u32 id;
+
+       addrs = skb_header_pointer(skb,
+                                  skb_network_offset(skb) +
+                                  offsetof(struct ipv6hdr, saddr),
+                                  sizeof(buf), buf);
+       if (!addrs)
+               return 0;
+
+       net_get_random_once(&ip6_proxy_idents_hashrnd,
+                           sizeof(ip6_proxy_idents_hashrnd));
+
+       id = __ipv6_select_ident(net, ip6_proxy_idents_hashrnd,
+                                &addrs[1], &addrs[0]);
+       return htonl(id);
+}
+EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
+
 __be32 ipv6_select_ident(struct net *net,
                         const struct in6_addr *daddr,
                         const struct in6_addr *saddr)