datapath: Fix mysterious GRE-over-IPSEC problems.

We've noticed that packets that go up to userspace and then back down to
the kernel and then enter an GRE tunnel that is then ESP encapsulated
by IPSEC end up with a bad ESP "next header" value: it ends up as zero
instead of 0x2f (IPPROTO_GRE).  Just putting packets from userspace into
a freshly allocated skb fixes the problem.

The underlying problem that this works around is still unknown.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Bug #4769.

diff --git a/datapath/datapath.c b/datapath/datapath.c
index e8ff4a5aab72c42fe3f7917a860e24ef83df0dfb..5ce77cd3485cf6e80afe36c8ad683b40bcfc8ed5 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -682,6 +682,7 @@ static int odp_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
        struct datapath *dp;
        struct ethhdr *eth;
        bool is_frag;
+       int len;
        int err;
 
        err = -EINVAL;
@@ -693,12 +694,14 @@ static int odp_packet_cmd_execute(struct sk_buff *skb, struct genl_info *info)
        if (err)
                goto err;
 
-       packet = skb_clone(skb, GFP_KERNEL);
+       len = nla_len(a[ODP_PACKET_ATTR_PACKET]);
+       packet = __dev_alloc_skb(NET_IP_ALIGN + len, GFP_KERNEL);
        err = -ENOMEM;
        if (!packet)
                goto err;
-       packet->data = nla_data(a[ODP_PACKET_ATTR_PACKET]);
-       packet->len = nla_len(a[ODP_PACKET_ATTR_PACKET]);
+       skb_reserve(packet, NET_IP_ALIGN);
+
+       memcpy(__skb_put(packet, len), nla_data(a[ODP_PACKET_ATTR_PACKET]), len);
 
        skb_reset_mac_header(packet);
        eth = eth_hdr(packet);