From 0982927c1bfe2a91b8244e148e3d7098b7c44ede Mon Sep 17 00:00:00 2001
From: Dominique Roux <dominique.roux4@gmail.com>
Date: Thu, 23 Jan 2020 18:43:41 +0100
Subject: [PATCH] Added DNSmasq ability for RA

---
 uncloud/hack/main.py | 10 ++++++----
 uncloud/hack/net.py  | 36 ++++++++++++++++++++++++++++++++++--
 2 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/uncloud/hack/main.py b/uncloud/hack/main.py
index f275e62..281c251 100644
--- a/uncloud/hack/main.py
+++ b/uncloud/hack/main.py
@@ -54,8 +54,10 @@ def main(arguments):
         vb._route_network()
 
     if arguments['run_dns_ra']:
-        if not arguments['network']:
-            raise UncloudException("Providing DNS/RAs requires a /64 IPv6 network. You can use fd00::/64 for testing (non production!)")
+        if not arguments['network'] or not arguments['vni']:
+            raise UncloudException("Providing DNS/RAs requires a /64 IPv6 network and a VNI. You can use fd00::/64 and vni=1 for testing (non production!)")
 
-        dnsra = DNSRA(arguments['network'])
-        dnsra.setup()
+        dnsra = DNSRA(route=arguments['network'], 
+                      vni=arguments['vni'],
+                      use_sudo=arguments['use_sudo'])
+        dnsra._setup_dnsmasq()
diff --git a/uncloud/hack/net.py b/uncloud/hack/net.py
index e18b36a..b036198 100644
--- a/uncloud/hack/net.py
+++ b/uncloud/hack/net.py
@@ -77,9 +77,41 @@ class ManagementBridge(VXLANBridge):
 
 
 class DNSRA(object):
-    def __init__(self):
-        pass
+    # VXLAN ids are at maximum 24 bit
+    max_vni = (2**24)-1
 
 
+    # Command to start dnsmasq
+    cmd_start_dnsmasq="{sudo}dnsmasq --interface={bridgedev} --bind-interfaces --dhcp-range={route},ra-only,infinite --enable-ra"
+
+    def __init__(self,
+                 vni,
+                 route=None,
+                 use_sudo=False):
+        self.config = {}
+
+        if vni > self.max_vni:
+            raise UncloudException("VNI must be in the range of 0 .. {}".format(self.max_vni))
+
+        if use_sudo:
+            self.config['sudo'] = 'sudo '
+
+        #TODO: remove if not needed
+        #self.config['vni_dec'] = vni
+        self.config['vni_hex'] = "{:x}".format(vni)
+
+        # dnsmasq only wants the network without the prefix, therefore, cut it off
+        self.config['route'] = ipaddress.IPv6Network(route).network_address
+        self.config['bridgedev'] = "br{}".format(self.config['vni_hex'])
+
+    def _setup_dnsmasq(self):
+         self._execute_cmd(self.cmd_start_dnsmasq)
+
+    def _execute_cmd(self, cmd_string, **kwargs):
+        cmd = cmd_string.format(**self.config, **kwargs)
+        log.info("Executing: {}".format(cmd))
+        print("Executing: {}".format(cmd))
+        subprocess.run(cmd.split())
+
 class Firewall(object):
     pass