[ovs-dev,PATCHv3] dpif-netlink-rtnl: Fix ovs_geneve probing after restart.

When using the out-of-tree (openvswitch compat) geneve module,
the first time oot tunnel probing returns true (correct).
Without unloading the geneve module, if the userspace ovs-vswitchd
restarts, because the 'geneve_sys_6081' still exists, the probing
incorrectly returns false and loads the in-tree (upstream kernel)
geneve module.

The patch fixes it by querying the geneve device's kind when exists.
The out-of-tree modules uses kind string as 'ovs_geneve', while the
in-tree module uses 'geneve'.  To reproduce the issue, start the ovs
> /etc/init.d/openvswitch-switch start
> creat a bridge and attach a geneve port using out-of-tree geneve
> /etc/init.d/openvswitch-switch restart

Fixes: 921c370a9df5 ("dpif-netlink: Probe for out-of-tree tunnels, decides used interface")
Signed-off-by: William Tu <u9012063@gmail.com>
Cc: Eric Garver <e@erig.me>
Cc: Gurucharan Shetty <guru@ovn.org>
---
v2->v3:
    Add return code checking for netlink parsing
    Fix memory leak
v1->v2:
    Add detection of existing module, instead of unconditionally
    remote it and create.
---
 lib/dpif-netlink-rtnl.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

On Thu, Nov 02, 2017 at 12:01:17PM -0700, William Tu wrote:
> When using the out-of-tree (openvswitch compat) geneve module,
> the first time oot tunnel probing returns true (correct).
> Without unloading the geneve module, if the userspace ovs-vswitchd
> restarts, because the 'geneve_sys_6081' still exists, the probing
> incorrectly returns false and loads the in-tree (upstream kernel)
> geneve module.
> 
> The patch fixes it by querying the geneve device's kind when exists.
> The out-of-tree modules uses kind string as 'ovs_geneve', while the
> in-tree module uses 'geneve'.  To reproduce the issue, start the ovs
> > /etc/init.d/openvswitch-switch start
> > creat a bridge and attach a geneve port using out-of-tree geneve
> > /etc/init.d/openvswitch-switch restart
> 
> Fixes: 921c370a9df5 ("dpif-netlink: Probe for out-of-tree tunnels, decides used interface")
> Signed-off-by: William Tu <u9012063@gmail.com>
> Cc: Eric Garver <e@erig.me>
> Cc: Gurucharan Shetty <guru@ovn.org>
> ---
> v2->v3:
>     Add return code checking for netlink parsing
>     Fix memory leak
> v1->v2:
>     Add detection of existing module, instead of unconditionally
>     remote it and create.
> ---
>  lib/dpif-netlink-rtnl.c | 39 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/lib/dpif-netlink-rtnl.c b/lib/dpif-netlink-rtnl.c
> index 0c32e7d8ccb4..fe9c8ed7104f 100644
> --- a/lib/dpif-netlink-rtnl.c
> +++ b/lib/dpif-netlink-rtnl.c
> @@ -440,6 +440,7 @@ dpif_netlink_rtnl_probe_oot_tunnels(void)
>  
>      error = netdev_open("ovs-system-probe", "geneve", &netdev);
>      if (!error) {
> +        struct ofpbuf *reply;
>          const struct netdev_tunnel_config *tnl_cfg;
>  
>          tnl_cfg = netdev_get_tunnel_config(netdev);
> @@ -448,6 +449,44 @@ dpif_netlink_rtnl_probe_oot_tunnels(void)
>          }
>  
>          name = netdev_vport_get_dpif_port(netdev, namebuf, sizeof namebuf);
> +
> +        /* The geneve module exists when ovs-vswitchd crashes
> +         * and restarts, handle the case here.
> +         */
> +        error = dpif_netlink_rtnl_getlink(name, &reply);
> +        if (!error) {
> +
> +            struct nlattr *linkinfo[ARRAY_SIZE(linkinfo_policy)];
> +            struct nlattr *rtlink[ARRAY_SIZE(rtlink_policy)];
> +            const char *kind;
> +
> +            if (!nl_policy_parse(reply,
> +                                 NLMSG_HDRLEN + sizeof(struct ifinfomsg),
> +                                 rtlink_policy, rtlink,
> +                                 ARRAY_SIZE(rtlink_policy))
> +                || !nl_parse_nested(rtlink[IFLA_LINKINFO], linkinfo_policy,
> +                                    linkinfo, ARRAY_SIZE(linkinfo_policy))) {
> +                VLOG_ABORT("Error fetching Geneve tunnel device %s "
> +                           "linkinfo", name);
> +            }
> +
> +            kind = nl_attr_get_string(linkinfo[IFLA_INFO_KIND]);
> +
> +            if (!strcmp(kind, "ovs_geneve")) {
> +                out_of_tree = true;
> +            } else if (!strcmp(kind, "geneve")) {
> +                out_of_tree = false;
> +            } else {
> +                VLOG_ABORT("Geneve tunnel device %s with kind %s"
> +                           " not supported", name, kind);
> +            }
> +
> +            ofpbuf_delete(reply);
> +            netdev_close(netdev);
> +
> +            return out_of_tree;
> +        }
> +
>          error = dpif_netlink_rtnl_create(tnl_cfg, name, OVS_VPORT_TYPE_GENEVE,
>                                           "ovs_geneve",
>                                           (NLM_F_REQUEST | NLM_F_ACK

This looks better. Thanks!

Acked-by: Eric Garver <e@erig.me>

On 2 November 2017 at 12:01, William Tu <u9012063@gmail.com> wrote:

> When using the out-of-tree (openvswitch compat) geneve module,
> the first time oot tunnel probing returns true (correct).
> Without unloading the geneve module, if the userspace ovs-vswitchd
> restarts, because the 'geneve_sys_6081' still exists, the probing
> incorrectly returns false and loads the in-tree (upstream kernel)
> geneve module.
>
> The patch fixes it by querying the geneve device's kind when exists.
> The out-of-tree modules uses kind string as 'ovs_geneve', while the
> in-tree module uses 'geneve'.  To reproduce the issue, start the ovs
> > /etc/init.d/openvswitch-switch start
> > creat a bridge and attach a geneve port using out-of-tree geneve
> > /etc/init.d/openvswitch-switch restart
>
> Fixes: 921c370a9df5 ("dpif-netlink: Probe for out-of-tree tunnels, decides
> used interface")
> Signed-off-by: William Tu <u9012063@gmail.com>
> Cc: Eric Garver <e@erig.me>
> Cc: Gurucharan Shetty <guru@ovn.org>
>

Thanks. I also tested this for a good reproduction case and applied to
master and 2.8.


> ---
> v2->v3:
>     Add return code checking for netlink parsing
>     Fix memory leak
> v1->v2:
>     Add detection of existing module, instead of unconditionally
>     remote it and create.
> ---
>  lib/dpif-netlink-rtnl.c | 39 +++++++++++++++++++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>
> diff --git a/lib/dpif-netlink-rtnl.c b/lib/dpif-netlink-rtnl.c
> index 0c32e7d8ccb4..fe9c8ed7104f 100644
> --- a/lib/dpif-netlink-rtnl.c
> +++ b/lib/dpif-netlink-rtnl.c
> @@ -440,6 +440,7 @@ dpif_netlink_rtnl_probe_oot_tunnels(void)
>
>      error = netdev_open("ovs-system-probe", "geneve", &netdev);
>      if (!error) {
> +        struct ofpbuf *reply;
>          const struct netdev_tunnel_config *tnl_cfg;
>
>          tnl_cfg = netdev_get_tunnel_config(netdev);
> @@ -448,6 +449,44 @@ dpif_netlink_rtnl_probe_oot_tunnels(void)
>          }
>
>          name = netdev_vport_get_dpif_port(netdev, namebuf, sizeof
> namebuf);
> +
> +        /* The geneve module exists when ovs-vswitchd crashes
> +         * and restarts, handle the case here.
> +         */
> +        error = dpif_netlink_rtnl_getlink(name, &reply);
> +        if (!error) {
> +
> +            struct nlattr *linkinfo[ARRAY_SIZE(linkinfo_policy)];
> +            struct nlattr *rtlink[ARRAY_SIZE(rtlink_policy)];
> +            const char *kind;
> +
> +            if (!nl_policy_parse(reply,
> +                                 NLMSG_HDRLEN + sizeof(struct ifinfomsg),
> +                                 rtlink_policy, rtlink,
> +                                 ARRAY_SIZE(rtlink_policy))
> +                || !nl_parse_nested(rtlink[IFLA_LINKINFO],
> linkinfo_policy,
> +                                    linkinfo,
> ARRAY_SIZE(linkinfo_policy))) {
> +                VLOG_ABORT("Error fetching Geneve tunnel device %s "
> +                           "linkinfo", name);
> +            }
> +
> +            kind = nl_attr_get_string(linkinfo[IFLA_INFO_KIND]);
> +
> +            if (!strcmp(kind, "ovs_geneve")) {
> +                out_of_tree = true;
> +            } else if (!strcmp(kind, "geneve")) {
> +                out_of_tree = false;
> +            } else {
> +                VLOG_ABORT("Geneve tunnel device %s with kind %s"
> +                           " not supported", name, kind);
> +            }
> +
> +            ofpbuf_delete(reply);
> +            netdev_close(netdev);
> +
> +            return out_of_tree;
> +        }
> +
>          error = dpif_netlink_rtnl_create(tnl_cfg, name,
> OVS_VPORT_TYPE_GENEVE,
>                                           "ovs_geneve",
>                                           (NLM_F_REQUEST | NLM_F_ACK
> --
> 2.7.4
>
>