[ovs-dev] [PATCH 1/2] datapath: Add pre_tunnel support

Jarno Rajahalme jarno.rajahalme at nsn.com
Wed Jan 23 14:01:33 UTC 2013


On Jan 22, 2013, at 20:36 , ext Kyle Mestery wrote:

> Add support to the tunneling code for a "pre_tunnel"
> function. This allows the tunneling code to perform
> operations on the packet before the outer IP header is
> added.
> 
> A tunneling protocol such as LISP may require this, as it needs
> to remove the MAC header before applying the LISP header.
> 

It seems to me that the same can be achieved with your own version of
ovs_tnl_send() that first removes the MAC header and then calls ovs_tnl_send().
Your vport_ops table already has the hook for this, so there is no overhead in
doing this.


> Signed-off-by: Kyle Mestery <kmestery at cisco.com>
> ---
> datapath/tunnel.c       | 5 +++++
> datapath/tunnel.h       | 7 +++++++
> datapath/vport-capwap.c | 1 +
> datapath/vport-gre.c    | 2 ++
> datapath/vport-vxlan.c  | 1 +
> 5 files changed, 16 insertions(+)
> 
> diff --git a/datapath/tunnel.c b/datapath/tunnel.c
> index d03b708..f1dd8d3 100644
> --- a/datapath/tunnel.c
> +++ b/datapath/tunnel.c
> @@ -988,6 +988,11 @@ int ovs_tnl_send(struct vport *vport, struct sk_buff *skb)
> 		if (unlikely(vlan_deaccel_tag(skb)))
> 			goto next;
> 
> +		/* Pre tunnel header work done by tunneling layer. */
> +		if (tnl_vport->tnl_ops->pre_tunnel)
> +			skb = tnl_vport->tnl_ops->pre_tunnel(vport, mutable,
> +							     skb);
> +
> 		skb_push(skb, tunnel_hlen);
> 		skb_reset_network_header(skb);
> 		skb_set_transport_header(skb, sizeof(struct iphdr));
> diff --git a/datapath/tunnel.h b/datapath/tunnel.h
> index b7de7a9..12e7f19 100644
> --- a/datapath/tunnel.h
> +++ b/datapath/tunnel.h
> @@ -135,6 +135,13 @@ struct tnl_ops {
> 	int (*hdr_len)(const struct tnl_mutable_config *,
> 		       const struct ovs_key_ipv4_tunnel *);
> 	/*
> +	 * Some tunnels may need to perform actions on the packet before
> +	 * appending the outer IP header of the tunneled packet.
> +	 */
> +	struct sk_buff *(*pre_tunnel)(const struct vport *,
> +				      const struct tnl_mutable_config *,
> +				      struct sk_buff *);
> +	/*
> 	 * Returns a linked list of SKBs with tunnel headers (multiple
> 	 * packets may be generated in the event of fragmentation).  Space
> 	 * will have already been allocated at the start of the packet equal
> diff --git a/datapath/vport-capwap.c b/datapath/vport-capwap.c
> index f45d349..9055b1d 100644
> --- a/datapath/vport-capwap.c
> +++ b/datapath/vport-capwap.c
> @@ -358,6 +358,7 @@ static const struct tnl_ops capwap_tnl_ops = {
> 	.tunnel_type	= TNL_T_PROTO_CAPWAP,
> 	.ipproto	= IPPROTO_UDP,
> 	.hdr_len	= capwap_hdr_len,
> +	.pre_tunnel	= NULL,
> 	.build_header	= capwap_build_header,
> };
> 
> diff --git a/datapath/vport-gre.c b/datapath/vport-gre.c
> index 8ce8a35..80f805a 100644
> --- a/datapath/vport-gre.c
> +++ b/datapath/vport-gre.c
> @@ -422,6 +422,7 @@ static const struct tnl_ops gre_tnl_ops = {
> 	.tunnel_type	= TNL_T_PROTO_GRE,
> 	.ipproto	= IPPROTO_GRE,
> 	.hdr_len	= gre_hdr_len,
> +	.pre_tunnel	= NULL,
> 	.build_header	= gre_build_header,
> };
> 
> @@ -439,6 +440,7 @@ static const struct tnl_ops gre64_tnl_ops = {
> 	.tunnel_type	= TNL_T_PROTO_GRE64,
> 	.ipproto	= IPPROTO_GRE,
> 	.hdr_len	= gre_hdr_len,
> +	.pre_tunnel	= NULL,
> 	.build_header	= gre_build_header,
> };
> 
> diff --git a/datapath/vport-vxlan.c b/datapath/vport-vxlan.c
> index f72b95f..4922486 100644
> --- a/datapath/vport-vxlan.c
> +++ b/datapath/vport-vxlan.c
> @@ -329,6 +329,7 @@ static const struct tnl_ops ovs_vxlan_tnl_ops = {
> 	.tunnel_type	= TNL_T_PROTO_VXLAN,
> 	.ipproto	= IPPROTO_UDP,
> 	.hdr_len	= vxlan_hdr_len,
> +	.pre_tunnel	= NULL,
> 	.build_header	= vxlan_build_header,
> };
> 
> -- 
> 1.7.11.7
> 
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