[RFC PATCH pve-common] network: add VPP bridge helpers for vhost-user dataplane

[Ryosuke Nakayama <ryosuke.nakayama@ryskn.com>]

From: unixtech <ryosuke_666@icloud.com>

- add is_vpp_bridge() to detect vppbrN interfaces
- skip tap_plug() for VPP bridges (vhost-user sockets are used instead
  of tap interfaces)
- skip read_bridge_mtu() kernel path for VPP bridges, return 1500

Signed-off-by: Ryosuke Nakayama <ryosuke.nakayama@ryskn.com>
Signed-off-by: unixtech <ryosuke.nakayama@ryskn.com>
---
 src/PVE/Network.pm | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/PVE/Network.pm b/src/PVE/Network.pm
index 573e34e..2c57ddb 100644
--- a/src/PVE/Network.pm
+++ b/src/PVE/Network.pm
@@ -128,6 +128,8 @@ sub tap_rate_limit {
 sub read_bridge_mtu {
     my ($bridge) = @_;
 
+    return 1500 if is_vpp_bridge($bridge);
+
     my $mtu = PVE::Tools::file_read_firstline("/sys/class/net/$bridge/mtu");
     die "bridge '$bridge' does not exist\n" if !$mtu;
 
@@ -515,6 +517,9 @@ sub tap_plug {
     $opts = {} if !defined($opts);
     $opts = { learning => $opts } if !ref($opts); # FIXME: backward compat, drop with PVE 8.0
 
+    # VPP bridges use vhost-user sockets, not tap devices
+    return if is_vpp_bridge($bridge);
+
     if (!defined($opts->{learning})) { # auto-detect
         $opts = {} if !defined($opts);
         my $interfaces_config = PVE::INotify::read_file('interfaces');
@@ -966,6 +971,11 @@ sub is_ovs_bridge {
     die "failed to query OVS to determine type of '$bridge': $res\n";
 }
 
+sub is_vpp_bridge {
+    my ($bridge) = @_;
+    return defined($bridge) && $bridge =~ /^vppbr\d+$/;
+}
+
 # for backward compat, prefer the methods from the leaner IPRoute2 module.
 sub ip_link_details {
     return PVE::IPRoute2::ip_link_details();
-- 
2.50.1 (Apple Git-155)