ipv6: Fragment locally generated tunnel-mode IPSec6 packets as needed.

This patch modifies IPsec6 to fragment IPv6 packets that are
locally generated as needed.

This version of the patch only fragments in tunnel mode, so that fragment
headers will not be obscured by ESP in transport mode.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 1 deletions

diff --git a/net/ipv6/xfrm6_output.c b/net/ipv6/xfrm6_output.c
index 6434bd5ce088..8e688b3de9ab 100644
--- a/net/ipv6/xfrm6_output.c
+++ b/net/ipv6/xfrm6_output.c
@@ -17,6 +17,7 @@
 #include <linux/netfilter_ipv6.h>
 #include <net/dst.h>
 #include <net/ipv6.h>
+#include <net/ip6_route.h>
 #include <net/xfrm.h>
 
 int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
@@ -88,8 +89,21 @@ static int xfrm6_output_finish(struct sk_buff *skb)
         return xfrm_output(skb);
 }
 
+static int __xfrm6_output(struct sk_buff *skb)
+{
+        struct dst_entry *dst = skb_dst(skb);
+        struct xfrm_state *x = dst->xfrm;
+
+        if ((x && x->props.mode == XFRM_MODE_TUNNEL) &&
+            ((skb->len > ip6_skb_dst_mtu(skb) && !skb_is_gso(skb)) ||
+                dst_allfrag(skb_dst(skb)))) {
+                        return ip6_fragment(skb, xfrm6_output_finish);
+        }
+        return xfrm6_output_finish(skb);
+}
+
 int xfrm6_output(struct sk_buff *skb)
 {
         return NF_HOOK(NFPROTO_IPV6, NF_INET_POST_ROUTING, skb, NULL,
-                       skb_dst(skb)->dev, xfrm6_output_finish);
+                       skb_dst(skb)->dev, __xfrm6_output);
 }