[ovs-dev] [PATCH v2.12] ovn: Prevent erroneous duplicate IP address messages.

[Mark Michelson]

In addition to applying this to 2.12, I am requesting a backport to 2.11 
as well. Thank you.

On 11/12/19 11:59 AM, Mark Michelson wrote:
> This is a backport to OVS 2.12 of OVN master commit 21c29d5b0c.
> 
> When using dynamic address assignment for logical switches, OVN reserves
> the first address in the subnet for the attached router port to use.
> 
> In commit 488d153ee87841c042af05bc0eb8b5481aaa98cf, the IPAM code was
> modified to add assigned router port addresses to IPAM. The use case for
> this was when a switch was joined to multiple routers, and all router
> addresses were dynamically assigned.
> 
> However, that commit also made it so that when a router rightly claimed
> the first address in the subnet, ovn-northd would issue a warning about
> a duplicate IP address being set. This change fixes the issue by adding
> a special case so that we don't add the router's IP address to IPAM if
> it is the first address in the subnet. This prevents the warning message
> from appearing.
> 
> Signed-off-by: Mark Michelson <mmichels at redhat.com>
> Acked-by: Numan Siddique <nusiddiq at redhat.com>
> Acked-by: Han ZHou <hzhou8 at ebay.com>
> ---
>   ovn/northd/ovn-northd.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
> index 6c6de2afd..1c9164924 100644
> --- a/ovn/northd/ovn-northd.c
> +++ b/ovn/northd/ovn-northd.c
> @@ -1194,7 +1194,14 @@ ipam_add_port_addresses(struct ovn_datapath *od, struct ovn_port *op)
>   
>           for (size_t i = 0; i < lrp_networks.n_ipv4_addrs; i++) {
>               uint32_t ip = ntohl(lrp_networks.ipv4_addrs[i].addr);
> -            ipam_insert_ip(op->peer->od, ip);
> +            /* If the router has the first IP address of the subnet, don't add
> +             * it to IPAM. We already added this when we initialized IPAM for
> +             * the datapath. This will just result in an erroneous message
> +             * about a duplicate IP address.
> +             */
> +            if (ip != op->peer->od->ipam_info.start_ipv4) {
> +                ipam_insert_ip(op->peer->od, ip);
> +            }
>           }
>   
>           destroy_lport_addresses(&lrp_networks);
>