Merge tag 'renesas-soc-cleanups-for-v3.19' of git://git.kernel.org/pub/scm/linux...

[cascardo/linux.git] / net / ipv6 / output_core.c

diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index fc24c39..97f41a3 100644 (file)
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -3,11 +3,45 @@
  * not configured or static.  These functions are needed by GSO/GRO implementation.
  */
 #include <linux/export.h>
+#include <net/ip.h>
 #include <net/ipv6.h>
 #include <net/ip6_fib.h>
 #include <net/addrconf.h>
 #include <net/secure_seq.h>
 
+/* 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.
+ */
+void ipv6_proxy_select_ident(struct sk_buff *skb)
+{
+       static u32 ip6_proxy_idents_hashrnd __read_mostly;
+       struct in6_addr buf[2];
+       struct in6_addr *addrs;
+       u32 hash, id;
+
+       addrs = skb_header_pointer(skb,
+                                  skb_network_offset(skb) +
+                                  offsetof(struct ipv6hdr, saddr),
+                                  sizeof(buf), buf);
+       if (!addrs)
+               return;
+
+       net_get_random_once(&ip6_proxy_idents_hashrnd,
+                           sizeof(ip6_proxy_idents_hashrnd));
+
+       hash = __ipv6_addr_jhash(&addrs[1], ip6_proxy_idents_hashrnd);
+       hash = __ipv6_addr_jhash(&addrs[0], hash);
+
+       id = ip_idents_reserve(hash, 1);
+       skb_shinfo(skb)->ip6_frag_id = htonl(id);
+}
+EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
+
 int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
 {
        u16 offset = sizeof(struct ipv6hdr);