[ovs-discuss] GRE over IPv6 configuration

[Eli Britstein]

On 6/18/2019 8:11 PM, William Tu wrote:
> On Tue, Jun 18, 2019 at 9:15 AM William Tu <u9012063 at gmail.com> wrote:
>> On Mon, Jun 17, 2019 at 10:46 PM Eli Britstein <elibr at mellanox.com> wrote:
>>>
>>> On 6/18/2019 1:22 AM, Gregory Rose wrote:
>>>> On 6/12/2019 2:20 AM, Eli Britstein wrote:
>>>>> Could you please have a look (and even better try?) still need to
>>>>> tidy up
>>>>>
>>>>> https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Felibr-mellanox%2Flinux%2Ftree%2Fovs-ipv6-gre&amp;data=02%7C01%7Celibr%40mellanox.com%7Cb5e034b901e54e2301b608d6f4100fe5%7Ca652971c7d2e4d9ba6a4d149256f461b%7C0%7C0%7C636964747162815714&amp;sdata=16q01k9tTgklmmTFeD6ZOmFwUSNzUAvVONJX8Y7FNEA%3D&amp;reserved=0
>>>>>
>>>>>
>>>>>
>>>> Hi Eli,
>>>>
>>>> I finally managed to getting around and building your kernel.  At
>>>> least it does do away with the protocol error message but
>>>> I haven't gotten it working yet.  Stay tuned and I'll provide feedback.
>>> Hi Greg,
>>>
>>> I think William was right pointing out the comment from Pravin. I agree
>>> with them that if we can avoid changing the kernel, and support it via
>>> lib/dpif-netlink-rtnl.c, it is the way to go, and we should abandon the
>>> kernel changes.
>>>
>>> I haven't deep dived into it yet to see how ip6erspan works (at least no
>>> creation error, didn't run traffic though) and ip6gre doesn't.
>>>
>> Hi Eli and Greg,
>>
>> I've found the root cause using upstream kernel 5.2.
>> When adding an ip6gre device type, the
>> ovs_vport_cmd_new
>>    new_vport
>>      netdev_create
>>        ovs_netdev_link
>>
>> and fails due to
>>      if (vport->dev->flags & IFF_LOOPBACK ||
>>          (vport->dev->type != ARPHRD_ETHER &&
>>           vport->dev->type != ARPHRD_NONE) ||
>>          ovs_is_internal_dev(vport->dev)) {
>>          err = -EINVAL;
>>
>> Because ip6gre is ARPHRD_IP6GRE
>> Which means ip6gre never works using upstream kernel :(
>>
>> If we use ip6gretap, then its type is ARPHRD_ETHER,
>> and the ip6gretap device can be created successfully.
>>
>> And for ip6erspan, it's never been a issue because it is ARPHRD_ETHER.
>>
>> And when using compat module, ip6gre works due to a coincident here:
>> at datapath/linux/compat/ip6_gre.c
>> static struct rtnl_link_ops ip6gre_link_ops __read_mostly = {
>>      .kind       = "ip6gre",
>>      .maxtype    = RPL_IFLA_GRE_MAX,
>>    <skip>
>>
>> static struct rtnl_link_ops ip6gre_tap_ops __read_mostly = {
>>      .kind       = "ip6gre",
>>      .maxtype    = RPL_IFLA_GRE_MAX,
>>      .policy     = ip6gre_policy,
>>      .priv_size  = sizeof(struct ip6_tnl),
>>
>> We happen to use ip6gre_tap link ops in type "ip6gre"
>>
>> Regards,
>> William
>>
>>> Furthermore, I think the following is missing, as there is no ip6gretap,
>>> only ip6gre:
>>>
> Hi Greg and Eli,
>
> Should we add both ip6gre (L3) and ip6gretap (L2) support?
> @Eli, which mode do you want to use?

ip6gretap

I applied this patch too, and indeed the error is resolved. However, i 
still don't get traffic. Have you verified it works to indicate a setup 
issue for me?

>
> I apply the patch below, and ip6gretap port can be created successfully
> by doing using kernel 5.2 upstream ovs module:
> # ovs-vsctl add-port br0 at_gre1 -- \
>       set int at_gre1 type=ip6gretap options:remote_ip=fc00:100::1
>
> but not the type=ip6gre
>
> diff --git a/lib/dpif-netlink-rtnl.c b/lib/dpif-netlink-rtnl.c
> index 2e23a8c14fcf..d666f239aeed 100644
> --- a/lib/dpif-netlink-rtnl.c
> +++ b/lib/dpif-netlink-rtnl.c
> @@ -104,7 +104,7 @@ vport_type_to_kind(enum ovs_vport_type type,
>       case OVS_VPORT_TYPE_IP6ERSPAN:
>           return "ip6erspan";
>       case OVS_VPORT_TYPE_IP6GRE:
> -        return "ip6gre";
> +        return "ip6gretap";
>       case OVS_VPORT_TYPE_NETDEV:
>       case OVS_VPORT_TYPE_INTERNAL:
>       case OVS_VPORT_TYPE_LISP:
> diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
> index c554666acce0..28897153744b 100644
> --- a/lib/dpif-netlink.c
> +++ b/lib/dpif-netlink.c
> @@ -698,7 +698,7 @@ get_vport_type(const struct dpif_netlink_vport *vport)
>           return "ip6erspan";
>
>       case OVS_VPORT_TYPE_IP6GRE:
> -        return "ip6gre";
> +        return "ip6gretap";
>
>       case OVS_VPORT_TYPE_UNSPEC:
>       case __OVS_VPORT_TYPE_MAX:
> @@ -729,7 +729,7 @@ netdev_to_ovs_vport_type(const char *type)
>           return OVS_VPORT_TYPE_ERSPAN;
>       } else if (!strcmp(type, "ip6erspan")) {
>           return OVS_VPORT_TYPE_IP6ERSPAN;
> -    } else if (!strcmp(type, "ip6gre")) {
> +    } else if (!strcmp(type, "ip6gretap")) {
>           return OVS_VPORT_TYPE_IP6GRE;
>       } else if (!strcmp(type, "gre")) {
>           return OVS_VPORT_TYPE_GRE;
> diff --git a/lib/netdev-vport.c b/lib/netdev-vport.c
> index ab591667f447..da95f680d454 100644
> --- a/lib/netdev-vport.c
> +++ b/lib/netdev-vport.c
> @@ -1216,10 +1216,10 @@ netdev_vport_tunnel_register(void)
>             },
>             {{NULL, NULL, 0, 0}}
>           },
> -        { "ip6gre_sys",
> +        { "ip6gretap_sys",
>             {
>                 TUNNEL_FUNCTIONS_COMMON,
> -              .type = "ip6gre",
> +              .type = "ip6gretap",
>                 .build_header = netdev_gre_build_header,
>                 .push_header = netdev_gre_push_header,
>                 .pop_header = netdev_gre_pop_header
> diff --git a/lib/tnl-ports.c b/lib/tnl-ports.c
> index 17353046cc6e..2157d7de11ae 100644
> --- a/lib/tnl-ports.c
> +++ b/lib/tnl-ports.c
> @@ -172,7 +172,7 @@ tnl_type_to_nw_proto(const char type[])
>           return IPPROTO_TCP;
>       }
>       if (!strcmp(type, "gre") || !strcmp(type, "erspan") ||
> -        !strcmp(type, "ip6erspan") || !strcmp(type, "ip6gre")) {
> +        !strcmp(type, "ip6erspan") || !strcmp(type, "ip6gretap")) {
>           return IPPROTO_GRE;
>       }
>       if (!strcmp(type, "vxlan")) {