From 926eaa3c2998b4cc56224a1f505fd8290f9f2708 Mon Sep 17 00:00:00 2001
From: Donald Buczek <buczek@molgen.mpg.de>
Date: Fri, 22 Sep 2023 12:29:10 +0200
Subject: [PATCH] mxrouterctl: Add veth feature

This adds a `veth(NAME)` config call which creates a pair of connected
veth devices, one in the default namespace and the other one on the
router namespace, both with the same name.

This can be used, for example, to create interfaces on the host for VMs
with the traffic routed through a mxrouter instance.

Example:

interface('vlan.irouter');
ip('vlan.irouter','172.19.141.2/24');
route('default','172.19.141.1');

veth('veth.variation');

my $NET_VARIATION = '172.19.118.0/24';
ip('veth.variation', '172.19.118.1/24');

my $NET_WISNET='141.14.16.0/20';

rule('filter','FORWARD',"-m state --state ESTABLISHED,RELATED -j ACCEPT");
rule('filter','FORWARD','-p icmp --icmp-type 8 -j ACCEPT');                  # ping

rule('filter','FORWARD',"-d $NET_VARIATION -j variation-out");
rule('filter','variation-out',"-s $NET_WISNET -p tcp --dport 22 -j ACCEPT"); # ssh
rule('filter','variation-out',"-j DROP");

rule('filter','FORWARD',"-j ACCEPT");
---
 mxrouter/mxrouterctl | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/mxrouter/mxrouterctl b/mxrouter/mxrouterctl
index 457241a..d394948 100755
--- a/mxrouter/mxrouterctl
+++ b/mxrouter/mxrouterctl
@@ -374,6 +374,7 @@ sub radvd {
 }
 
 our $want_if;
+our $want_veth;
 
 our $DHCRELAY_FORWARD;
 our %DHCRELAY_IF;
@@ -483,7 +484,7 @@ sub start {
 
 	netif_is_up('lo') or sys('ip link set lo up');
 
-	for my $dev (keys %$want_if) {
+	for my $dev (keys %$want_if, keys %$want_veth) {
 		netif_is_up($dev) or sys('ip','link','set',$dev,'up');
 	}
 
@@ -622,6 +623,11 @@ sub interface {
 	$want_if->{$dev}=1;
 }
 
+sub veth {
+	my ($dev) = @_;
+	$want_veth->{$dev} = 1;
+}
+
 my @SAVED_ARGV=@ARGV;
 
 GetOptions(OPTIONS) or die USAGE;
@@ -776,6 +782,9 @@ if (!$opt_this_ns) {
 		for my $dev (sort keys %$want_if) {
 			move_dev_into_ns($dev,$NETNS);
 		}
+		for my $dev (sort keys %$want_veth) {
+			sys('ip', 'link', 'add', $dev, 'type', 'veth', 'peer', 'name', $dev, 'netns', $NETNS);
+		}
 		system('ip','netns','exec',$NETNS,$0,'--this-ns',@SAVED_ARGV) and exit 1;
 	} elsif ($cmd eq 'stop') {
 		have_netns($NETNS) or die "not running (network namespace $NETNS does not exist)\n";