Subject: Re: [ovs-dev] [RFC net-next 4/7] selftests: openvswitch: Add support for tunnel() key.

From: Simon Horman <[email-masked]>
Date: Sun, 16 Jun 2024 17:27:43 +0100

On Thu, Jun 13, 2024 at 02:13:30PM -0400, Aaron Conole wrote:
> This will be used when setting details about the tunnel to use as
> transport.  There is a difference between the ODP format between tunnel():
> the 'key' flag is not actually a flag field, so we don't support it in the
> same way that the vswitchd userspace supports displaying it.
> 
> Signed-off-by: Aaron Conole <[email-masked]>

...

> @@ -1265,6 +1265,165 @@ class ovskey(nla):
>                  init=init,
>              )
>  
> +    class ovs_key_tunnel(nla):
> +        nla_flags = NLA_F_NESTED
> +
> +        nla_map = (
> +            ("OVS_TUNNEL_KEY_ATTR_ID", "be64"),
> +            ("OVS_TUNNEL_KEY_ATTR_IPV4_SRC", "ipaddr"),
> +            ("OVS_TUNNEL_KEY_ATTR_IPV4_DST", "ipaddr"),
> +            ("OVS_TUNNEL_KEY_ATTR_TOS", "uint8"),
> +            ("OVS_TUNNEL_KEY_ATTR_TTL", "uint8"),
> +            ("OVS_TUNNEL_KEY_ATTR_DONT_FRAGMENT", "flag"),
> +            ("OVS_TUNNEL_KEY_ATTR_CSUM", "flag"),
> +            ("OVS_TUNNEL_KEY_ATTR_OAM", "flag"),
> +            ("OVS_TUNNEL_KEY_ATTR_GENEVE_OPTS", "array(uint32)"),
> +            ("OVS_TUNNEL_KEY_ATTR_TP_SRC", "be16"),
> +            ("OVS_TUNNEL_KEY_ATTR_TP_DST", "be16"),
> +            ("OVS_TUNNEL_KEY_ATTR_VXLAN_OPTS", "none"),
> +            ("OVS_TUNNEL_KEY_ATTR_IPV6_SRC", "ipaddr"),
> +            ("OVS_TUNNEL_KEY_ATTR_IPV6_DST", "ipaddr"),
> +            ("OVS_TUNNEL_KEY_ATTR_PAD", "none"),
> +            ("OVS_TUNNEL_KEY_ATTR_ERSPAN_OPTS", "none"),
> +            ("OVS_TUNNEL_KEY_ATTR_IPV4_INFO_BRIDGE", "flag"),
> +        )
> +
> +        def parse(self, flowstr, mask=None):
> +            if not flowstr.startswith("tunnel("):
> +                return None, None
> +
> +            k = ovskey.ovs_key_tunnel()
> +            if mask is not None:
> +                mask = ovskey.ovs_key_tunnel()
> +
> +            flowstr = flowstr[len("tunnel("):]
> +
> +            v6_address = None
> +
> +            fields = [
> +                ("tun_id=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_ID",
> +                 0xffffffffffffffff, None, None),
> +
> +                ("src=", r"([0-9a-fA-F\.]+)", str,
> +                 "OVS_TUNNEL_KEY_ATTR_IPV4_SRC", "255.255.255.255", "0.0.0.0",
> +                 False),
> +                ("dst=", r"([0-9a-fA-F\.]+)", str,
> +                 "OVS_TUNNEL_KEY_ATTR_IPV4_DST", "255.255.255.255", "0.0.0.0",
> +                 False),
> +
> +                ("ipv6_src=", r"([0-9a-fA-F:]+)", str,
> +                 "OVS_TUNNEL_KEY_ATTR_IPV6_SRC",
> +                 "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "::", True),
> +                ("ipv6_dst=", r"([0-9a-fA-F:]+)", str,
> +                 "OVS_TUNNEL_KEY_ATTR_IPV6_DST",
> +                 "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff", "::", True),
> +
> +                ("tos=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TOS", 255, 0,
> +                 None),
> +                ("ttl=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TTL", 255, 0,
> +                 None),
> +
> +                ("tp_src=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TP_SRC",
> +                 65535, 0, None),
> +                ("tp_dst=", r"(\d+)", int, "OVS_TUNNEL_KEY_ATTR_TP_DST",
> +                 65535, 0, None),
> +            ]
> +
> +            forced_include = ["OVS_TUNNEL_KEY_ATTR_TTL"]
> +
> +            for prefix, regex, typ, attr_name, mask_val, default_val, v46_flag in fields:
> +                flowstr, value = parse_extract_field(flowstr, prefix, regex, typ, False)
> +                if not attr_name:
> +                    raise Exception("Bad list value in tunnel fields")
> +
> +                if value is None and attr_name in forced_include:
> +                    value = default_val
> +                    mask_val = default_val
> +
> +                if value is not None:
> +                    if v6_address is None and v46_flag is not None:
> +                        v6_address = v46_flag

By my reading, at this point v6_address will only be None if v46_flag is
not None.  IF so, the condition below seems excessive.

> +                    if v6_address is not None and v46_flag is not None \
> +                       and v46_flag != v6_address:
> +                        raise ValueError("Cannot mix v6 and v4 addresses")

I wonder if we can instead express this as (completely untested!):

                    if v46_flag is not None:
                        if v6_address is None:
                            v6_address = v46_flag
                        if v46_flag != v6_address:
                            raise ValueError("Cannot mix v6 and v4 addresses")

> +                    k["attrs"].append([attr_name, value])
> +                    if mask is not None:
> +                        mask["attrs"].append([attr_name, mask_val])
> +                else:
> +                    if v6_address is not None and v46_flag is not None \
> +                       and v46_flag != v6_address:
> +                        continue
> +                    if v6_address is None and v46_flag is not None:
> +                        continue

And I wonder if this is a bit easier on the eyes (also completely untested):

                    if v46_flag is not None:
                        if v6_address is None or v46_flag != v6_address:
                            continue

> +                    if mask is not None:
> +                        mask["attrs"].append([attr_name, default_val])
> +
> +            if k["attrs"][0][0] != "OVS_TUNNEL_KEY_ATTR_ID":
> +                raise ValueError("Needs a tunid set")

...

> @@ -1745,7 +1905,7 @@ class OvsVport(GenericNetlinkSocket):
>          )
>  
>          TUNNEL_DEFAULTS = [("geneve", 6081),
> -                           ("vxlan", 4798)]
> +                           ("vxlan", 4789)]
>  
>          for tnl in TUNNEL_DEFAULTS:
>              if ptype == tnl[0]:

As noted in my response to PATCH 1/7, I think that the
change in the hunk above belongs there rather than here.