From 28c3a6385143c97c3255f2a476523b103d3b830d Mon Sep 17 00:00:00 2001
From: Christian Poessinger <christian@poessinger.com>
Date: Fri, 16 Mar 2018 21:00:43 +0100
Subject: Initial working version for XML interface to configure dnsmasq

---
 Makefile                                    |   1 +
 src/conf-mode/vyos-config-dns-forwarding.py | 119 +++++++++++++++++++++++++++-
 2 files changed, 119 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index f5800da43..de7c136eb 100644
--- a/Makefile
+++ b/Makefile
@@ -10,6 +10,7 @@ interface_definitions:
 	# XXX: delete top level node.def's that now live in other packages
 	rm -f $(TMPL_DIR)/system/node.def
 	rm -f $(TMPL_DIR)/service/node.def
+	rm -f $(TMPL_DIR)/service/dns/node.def
 	rm -f $(TMPL_DIR)/protocols/node.def
 
 .PHONY: all
diff --git a/src/conf-mode/vyos-config-dns-forwarding.py b/src/conf-mode/vyos-config-dns-forwarding.py
index 27e7a5ef5..cdbd89eba 100755
--- a/src/conf-mode/vyos-config-dns-forwarding.py
+++ b/src/conf-mode/vyos-config-dns-forwarding.py
@@ -18,20 +18,137 @@
 
 import sys
 import os
+import time
 
 from vyos.config import Config
 from vyos.util import ConfigError
 
+config_file = r'/etc/dnsmasq.d/vyos.conf'
+
+# borrowed from: https://github.com/donjajo/py-world/blob/master/resolvconfReader.py, THX!
+def get_resolvers(file):
+    resolvers = []
+    try:
+        with open(file, 'r') as resolvconf:
+            for line in resolvconf.readlines():
+                line = line.split('#',1)[0];
+                line = line.rstrip();
+                if 'nameserver' in line:
+                    resolvers.append(line.split()[1])
+        return resolvers
+    except IOError as error:
+        return error.strerror
+
 def get_config():
-    return None
+    dns = {}
+    conf = Config()
+    conf.set_level('service dns forwarding')
+    if not conf.exists(''):
+        return dns
+
+    if conf.exists('cache-size'):
+        cache = conf.return_value('cache-size')
+        dns.setdefault('cache-size', cache)
+
+    if conf.exists('dhcp'):
+        dns.setdefault('dhcp', [])
+        interfaces = []
+        interfaces = conf.return_values('dhcp')
+        for interface in interfaces:
+            resolvers = get_resolvers("/etc/resolv.conf.dhclient-new-{0}".format(interface))
+            dhcp = {
+                "interface": interface,
+                "resolvers": resolvers
+            }
+            dns['dhcp'].append(dhcp)
+
+    if conf.exists('domain'):
+        dns.setdefault('domain', [])
+        for node in conf.list_nodes('domain'):
+            server = conf.return_value("domain {0} server".format(node))
+            domain = {
+                "name": node,
+                "server": server
+            }
+            dns['domain'].append(domain)
+
+    if conf.exists('ignore-hosts-file'):
+        dns.setdefault('ignore-hosts-file', True)
+
+    if conf.exists('listen-on'):
+        interfaces = []
+        interfaces = conf.return_values('listen-on')
+        dns.setdefault('listen-on', interfaces)
+
+    if conf.exists('name-server'):
+        nameservers = []
+        nameservers = conf.return_values('name-server')
+        dns.setdefault('name-server', nameservers)
+
+    if conf.exists('system'):
+        conf.set_level('system')
+        nameservers = []
+        nameservers = conf.return_values('name-server')
+        if len(nameservers) == 0:
+            print("DNS forwarding warning: No name-servers set under 'system name-server'\n")
+        dns.setdefault('system-name-server', True)
+
+    return dns
 
 def verify(dns):
+    if 'listen-on' not in dns.keys():
+        raise ConfigError("Error: DNS forwarding requires a configured listen interface!")
+
     return None
 
 def generate(dns):
+    config_header = '### Autogenerated by vyos-config-dns-forwarding.py on {tm} ###\n'.format(tm=time.strftime("%a, %d %b %Y %H:%M:%S", time.localtime()))
+
+    # write new configuration file
+    f = open(config_file, 'w')
+    f.write(config_header)
+    f.write("log-facility=/var/log/dnsmasq.log\n")
+    f.write("no-poll\n")
+    f.write("edns-packet-max=4096\n")
+    f.write("bind-interfaces\n")
+
+    if 'listen-on' in dns.keys():
+        for interface in dns['listen-on']:
+            f.write("interface={0}\n".format(interface))
+
+    if 'dhcp' in dns.keys():
+        for dhcp in dns['dhcp']:
+            for resolver in dhcp['resolvers']:
+                f.write("server={0}\t# dhcp {1}\n".format(resolver, dhcp['interface']))
+
+    if 'domain' in dns.keys():
+        for domain in dns['domain']:
+            f.write("server=/{0}/{1}\t# domain-override\n".format(domain['name'], domain['server']))
+
+    if 'cache-size' in dns.keys():
+        f.write("cache-size={0}\n".format(dns['cache-size']))
+
+    if 'ignore-hosts-file' in dns.keys():
+        f.write("no-hosts\n")
+
+    if 'name-server' in dns.keys():
+        for nameserver in dns['name-server']:
+            f.write("server={0}\t# statically configured\n".format(nameserver))
+
+    if 'system-name-server' in dns.keys():
+        # Read the IP addresses of the upstream nameservers from /etc/resolv.conf
+        f.write("resolv-file=/etc/resolv.conf\n")
+
+    f.close()
     return None
 
 def apply(dns):
+    if len(dns) == 0:
+        cmd = "sudo systemctl stop dnsmasq"
+    else:
+        cmd = "sudo systemctl restart dnsmasq"
+
+    os.system(cmd)
     return None
 
 if __name__ == '__main__':
-- 
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