On 3/26/2019 9:31 AM, Pravin Shelar wrote:
On Mon, Mar 25, 2019 at 5:44 PM <nusid...@redhat.com> wrote:From: Numan Siddique <nusid...@redhat.com> This patch adds a new action - 'check_pkt_len' which checks the packet length and executes a set of actions if the packet length is greater than the specified length or executes another set of actions if the packet length is lesser or equal to. This action takes below nlattrs * OVS_CHECK_PKT_LEN_ATTR_PKT_LEN - 'pkt_len' to check for * OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_GREATER - Nested actions to apply if the packet length is greater than the specified 'pkt_len' * OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL - Nested actions to apply if the packet length is lesser or equal to the specified 'pkt_len'. The main use case for adding this action is to solve the packet drops because of MTU mismatch in OVN virtual networking solution. When a VM (which belongs to a logical switch of OVN) sends a packet destined to go via the gateway router and if the nic which provides external connectivity, has a lesser MTU, OVS drops the packet if the packet length is greater than this MTU. With the help of this action, OVN will check the packet length and if it is greater than the MTU size, it will generate an ICMP packet (type 3, code 4) and includes the next hop mtu in it so that the sender can fragment the packets. Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2018-July/047039.html Suggested-by: Ben Pfaff <b...@ovn.org> Signed-off-by: Numan Siddique <nusid...@redhat.com> CC: Gregory Rose <gvrose8...@gmail.com> CC: Pravin B Shelar <pshe...@ovn.org> --- v1 -> v2 ----- * Addressed the review comments. - Removed the vlan-tag length when checking the packet length - Reordered the netlink attributes - Changed the comments to use 'attribute' instead of 'action' Corresponding OVS patch (submitted as RFC for now) which makes use of this action can be found here - https://patchwork.ozlabs.org/patch/1059081/Looks good to me. Acked-by: Pravin B Shelar <pshe...@ovn.org>
Tested-by: Greg Rose <gvrose8...@gmail.com> Reviewed-by: Greg Rose <gvrose8...@gmail.com>
