ah6/esp6: set transport header correctly for IPsec tunnel mode.

IPsec tunnel does not set ECN field to CE in inner header when
the ECN field in the outer header is CE, and the ECN field in
the inner header is ECT(0) or ECT(1).

The cause is ipip6_hdr() does not return the correct address of
inner header since skb->transport-header is not the inner header
after esp6_input_done2(), or ah6_input().

Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

2 files changed, 13 insertions, 3 deletions

diff --git a/net/ipv6/ah6.c b/net/ipv6/ah6.c
index ecc35b93314b..384233188ac1 100644
--- a/net/ipv6/ah6.c
+++ b/net/ipv6/ah6.c
@@ -472,7 +472,10 @@ static void ah6_input_done(struct crypto_async_request *base, int err)
         skb->network_header += ah_hlen;
         memcpy(skb_network_header(skb), work_iph, hdr_len);
         __skb_pull(skb, ah_hlen + hdr_len);
-        skb_set_transport_header(skb, -hdr_len);
+        if (x->props.mode == XFRM_MODE_TUNNEL)
+                skb_reset_transport_header(skb);
+        else
+                skb_set_transport_header(skb, -hdr_len);
 out:
         kfree(AH_SKB_CB(skb)->tmp);
         xfrm_input_resume(skb, err);
@@ -593,9 +596,13 @@ static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
 
         skb->network_header += ah_hlen;
         memcpy(skb_network_header(skb), work_iph, hdr_len);
-        skb->transport_header = skb->network_header;
         __skb_pull(skb, ah_hlen + hdr_len);
 
+        if (x->props.mode == XFRM_MODE_TUNNEL)
+                skb_reset_transport_header(skb);
+        else
+                skb_set_transport_header(skb, -hdr_len);
+
         err = nexthdr;
 
 out_free:
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 282f3723ee19..40ffd72243a4 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -300,7 +300,10 @@ static int esp_input_done2(struct sk_buff *skb, int err)
 
         pskb_trim(skb, skb->len - alen - padlen - 2);
         __skb_pull(skb, hlen);
-        skb_set_transport_header(skb, -hdr_len);
+        if (x->props.mode == XFRM_MODE_TUNNEL)
+                skb_reset_transport_header(skb);
+        else
+                skb_set_transport_header(skb, -hdr_len);
 
         err = nexthdr[1];