gre: Ensure skb properties are consistently set.

The skb local fragmentation and checksum offloading properties were
sometimes either overwritten or not copied by later operations.  This
ensures that they are consistently correct and solves issues like
TSO not working in certain circumstances on 2.6.18 kernels.

diff --git a/datapath/vport-gre.c b/datapath/vport-gre.c
index a272b8a..fdf526e 100644 (file)
--- a/datapath/vport-gre.c
+++ b/datapath/vport-gre.c
@@ -728,8 +728,10 @@ handle_csum_offload(struct sk_buff *skb)
 {
        if (skb->ip_summed == CHECKSUM_PARTIAL)
                return skb_checksum_help(skb);
-       else
+       else {
+               skb->ip_summed = CHECKSUM_NONE;
                return 0;
+       }
 }
 
 /* Called with rcu_read_lock and bottom-halves disabled. */
@@ -960,6 +962,10 @@ build_packet(struct vport *vport, const struct mutable_config *mutable,
 
        create_gre_header(skb, mutable);
 
+       /* Allow our local IP stack to fragment the outer packet even if the
+        * DF bit is set as a last resort. */
+       skb->local_df = 1;
+
        memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
        IPCB(skb)->flags = 0;
 
@@ -1067,15 +1073,10 @@ gre_send(struct vport *vport, struct sk_buff *skb)
        iph.daddr = rt->rt_dst;
        iph.saddr = rt->rt_src;
 
-       /* Allow our local IP stack to fragment the outer packet even if the
-        * DF bit is set as a last resort. */
-       skb->local_df = 1;
-
        nf_reset(skb);
        secpath_reset(skb);
        skb_dst_drop(skb);
        skb_dst_set(skb, &rt->u.dst);
-       skb->ip_summed = CHECKSUM_NONE;
 
        /* If we are doing GSO on a pskb it is better to make sure that the
         * headroom is correct now.  We will only have to copy the portion in
@@ -1092,14 +1093,16 @@ gre_send(struct vport *vport, struct sk_buff *skb)
                }
        }
 
+       forward_ip_summed(skb);
        vswitch_skb_checksum_setup(skb);
+
        skb = handle_gso(skb);
        if (unlikely(IS_ERR(skb))) {
                vport_record_error(vport, VPORT_E_TX_DROPPED);
                goto error;
        }
 
-       /* Process GSO segments.  Try to do any work on the entire packet that
+       /* Process GSO segments.  Try to do any work for the entire packet that
         * doesn't involve actually writing to it before this point. */
        orig_len = 0;
        do {