From 1a384ed21f1777faaef653f9d1e3d9c05542fdc8 Mon Sep 17 00:00:00 2001
From: hagbard <vyosdev@derith.de>
Date: Fri, 22 Mar 2019 12:57:43 -0700
Subject: Fixes: T1262 - dhcp requested WAN ip address doesn't get search
 parameter in /etc/resolv.conf

---
 src/conf_mode/host_name.py | 266 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 202 insertions(+), 64 deletions(-)

diff --git a/src/conf_mode/host_name.py b/src/conf_mode/host_name.py
index 030735215..27e2d9170 100755
--- a/src/conf_mode/host_name.py
+++ b/src/conf_mode/host_name.py
@@ -24,98 +24,236 @@ import os
 import re
 import sys
 import subprocess
+import copy
+import jinja2
+import glob
 
 from vyos.config import Config
 from vyos import ConfigError
 
+config_file_hosts = '/etc/hosts'
+config_file_resolv = '/etc/resolv.conf'
 
-hosts_file = '/etc/hosts'
-hostname_regex = re.compile("^[A-Za-z0-9][-.A-Za-z0-9]*[A-Za-z0-9]$")
-local_addr = '127.0.1.1' # NOSONAR
+config_tmpl_hosts = """
+### Autogenerated by host_name.py ###
+127.0.0.1       localhost {{ hostname }}{% if domain_name %}.{{ domain_name }}{% endif %}
 
+# The following lines are desirable for IPv6 capable hosts
+::1             localhost ip6-localhost ip6-loopback
+fe00::0         ip6-localnet
+ff00::0         ip6-mcastprefix
+ff02::1         ip6-allnodes
+ff02::2         ip6-allrouters
+
+# static hostname mappings
+{%- if static_host_mapping['hostnames'] %}
+{% for hn in static_host_mapping['hostnames'] -%}
+{{static_host_mapping['hostnames'][hn]['ipaddr']}}\t{{static_host_mapping['hostnames'][hn]['alias']}}\t{{hn}}
+{% endfor -%}
+{%- endif %}
+
+### modifications from other scripts should be added below
+
+"""
+
+config_tmpl_resolv = """
+### Autogenerated by host_name.py ###
+{% for ns in nameserver -%}
+nameserver {{ ns }}
+{% endfor -%}
+
+{%- if domain_name %}
+domain {{ domain_name }}
+{%- endif %}
+
+{%- if domain_search %}
+search {{ domain_search | join(" ") }}
+{%- endif %}
+
+"""
+
+# 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:
+    return []
+
+def get_dhcp_search_doms(file):
+  search_doms = []
+  try:
+    with open(file, 'r') as resolvconf:
+      for line in resolvconf.readlines():
+        line = line.split('#',1)[0];
+        line = line.rstrip();
+        if 'search' in line:
+          return re.sub('^search','',line).lstrip().split()
+  except IOError:
+    return []
+
+default_config_data = {
+    'hostname': 'vyos',
+    'domain_name': '',
+    'domain_search': [],
+    'nameserver': [],
+    'no_dhcp_ns': False
+}
 
 def get_config():
-    """Get configuration"""
-    conf = Config()
+  conf = Config()
+  hosts = copy.deepcopy(default_config_data)
 
-    hostname = conf.return_value("system host-name")
-    domain = conf.return_value("system domain-name")
+  hosts['hostname'] = conf.return_value("system host-name")
+  hosts['domain_name'] = conf.return_value("system domain-name")
 
-    # No one likes fixups, but we really don't want VyOS fail to boot
-    # if hostname is not in the config
-    if not hostname:
-        hostname = "vyos"
+  if hosts['domain_name']:
+    hosts['domain_search'].append(hosts['domain_name'])
 
-    if domain:
-        fqdn = "{0}.{1}".format(hostname, domain)
-    else:
-        fqdn = hostname
+  for search in conf.return_values("system domain-search domain"):
+    hosts['domain_search'].append(search)
 
-    return {"hostname": hostname, "domain": domain, "fqdn": fqdn}
+  hosts['nameserver'] = conf.return_values("system name-server")
+  hosts['no_dhcp_ns'] = conf.exists('system disable-dhcp-nameservers')
 
+  ## system static-host-mapping
+  hosts['static_host_mapping'] = { 'hostnames'  : {}}
+
+  if conf.exists('system static-host-mapping host-name'):
+    for hn in conf.list_nodes('system static-host-mapping host-name'):
+      hosts['static_host_mapping']['hostnames'][hn] = {
+        'ipaddr'  : conf.return_value('system static-host-mapping host-name ' + hn + ' inet'),
+        'alias'   : '' 
+      }
+      
+      if conf.exists('system static-host-mapping host-name ' + hn + ' alias'):
+        a = conf.return_values('system static-host-mapping host-name ' + hn + ' alias')
+        hosts['static_host_mapping']['hostnames'][hn]['alias'] = " ".join( conf.return_values('system static-host-mapping host-name ' + hn + ' alias') )
+
+  return hosts
 
 def verify(config):
-    """Verify configuration"""
-    # check for invalid host
+  if config is None:
+    return None
 
-    # pattern $VAR(@) "^[[:alnum:]][-.[:alnum:]]*[[:alnum:]]$" ; "invalid host name $VAR(@)"
-    if not hostname_regex.match(config["hostname"]):
-        raise ConfigError('Invalid host name ' + config["hostname"])
+  # pattern $VAR(@) "^[[:alnum:]][-.[:alnum:]]*[[:alnum:]]$" ; "invalid host name $VAR(@)"
+  hostname_regex = re.compile("^[A-Za-z0-9][-.A-Za-z0-9]*[A-Za-z0-9]$")
+  if not hostname_regex.match(config['hostname']):
+    raise ConfigError('Invalid host name ' + config["hostname"])
 
-    # pattern $VAR(@) "^.{1,63}$" ; "invalid host-name length"
-    length = len(config["hostname"])
-    if length < 1 or length > 63:
-        raise ConfigError(
-            'Invalid host-name length, must be less than 63 characters')
+  # pattern $VAR(@) "^.{1,63}$" ; "invalid host-name length"
+  length = len(config['hostname'])
+  if length < 1 or length > 63:
+    raise ConfigError('Invalid host-name length, must be less than 63 characters')
 
-    return None
+  # The search list is currently limited to six domains with a total of 256 characters.
+  # https://linux.die.net/man/5/resolv.conf
+  if len(config['domain_search']) > 6:
+    raise ConfigError('The search list is currently limited to six domains')
 
+  tmp = ' '.join(config['domain_search'])
+  if len(tmp) > 256:
+    raise ConfigError('The search list is currently limited to 256 characters')
 
-def generate(config):
-    """Generate configuration files"""
-    # read the hosts file
-    with open(hosts_file, 'r') as f:
-        hosts = f.read()
-
-    # get the current hostname
-    old_hostname = subprocess.check_output(['hostname']).decode().strip()
-
-    # replace the local host line
-    vyos_host_line_re = re.compile(r"({}\s+{}.*)".format(local_addr, old_hostname))
-    vyos_host_line = "{}\t{} # VyOS entry\n".format(local_addr, config["fqdn"])
-    if re.search(vyos_host_line_re, hosts):
-        hosts = re.sub(vyos_host_line_re, vyos_host_line, hosts)
-    else:
-        # On boot (or after errors), the /etc/hosts file has no line for vyos hostname,
-        # so we have to add it
-        hosts = "{0}\n{1}".format(hosts, vyos_host_line)
-
-    with open(hosts_file, 'w') as f:
-        f.write(hosts)
+  # static mappings alias hostname
+  if config['static_host_mapping']['hostnames']:
+    for hn in config['static_host_mapping']['hostnames']:
+      if not config['static_host_mapping']['hostnames'][hn]['ipaddr']:
+        raise ConfigError('IP address required for ' + hn)
+      for hn_alias in config['static_host_mapping']['hostnames'][hn]['alias'].split(' '):
+        if not hostname_regex.match(hn_alias) and len (hn_alias) !=0:
+          raise ConfigError('Invalid hostname alias ' + hn_alias)
 
+  return None
+
+def generate(config):
+  if config is None:
     return None
 
+  # If "system disable-dhcp-nameservers" is __configured__ all DNS resolvers
+  # received via dhclient should not be added into the final 'resolv.conf'.
+  #
+  # We iterate over every resolver file and retrieve the received nameservers
+  # for later adjustment of the system nameservers
+  dhcp_ns = []
+  for file in glob.glob('/etc/resolv.conf.dhclient-new*'):
+    for r in get_resolvers(file):
+      dhcp_ns.append(r)
 
-def apply(config):
-    """Apply configuration"""
-    os.system("hostnamectl set-hostname --static {0}".format(config["fqdn"]))
+  if not config['no_dhcp_ns']:
+    config['nameserver'] += dhcp_ns
+    for file in glob.glob('/etc/resolv.conf.dhclient-new*'):
+      config['domain_search'] = get_dhcp_search_doms(file)
+
+  # We have third party scripts altering /etc/hosts, too.
+  # One example are the DHCP hostname update scripts thus we need to cache in
+  # every modification first - so changing domain-name, domain-search or hostname
+  # during runtime works
+  old_hosts = ""
+  with open(config_file_hosts, 'r') as f:
+    # Skips text before the beginning of our marker.
+    # NOTE: Marker __MUST__ match the one specified in config_tmpl_hosts
+    for line in f:
+      if line.strip() == '### modifications from other scripts should be added below':
+        break
+
+    for line in f:
+      # This additional line.strip() filters empty lines
+      if line.strip():
+        old_hosts += line
+
+  # Add an additional newline
+  old_hosts += '\n'
 
-    # Restart services that use the hostname
-    os.system("systemctl restart rsyslog.service")
+  tmpl = jinja2.Template(config_tmpl_hosts)
+  config_text = tmpl.render(config)
 
-    # If SNMP is running, restart it too
-    if os.system("pgrep snmpd > /dev/null") == 0:
-        os.system("systemctl restart snmpd.service")
+  with open(config_file_hosts, 'w') as f:
+    f.write(config_text)
+    f.write(old_hosts)
 
+  tmpl = jinja2.Template(config_tmpl_resolv)
+  config_text = tmpl.render(config)
+  with open(config_file_resolv, 'w') as f:
+    f.write(config_text)
+
+  return None
+
+def apply(config):
+  if config is None:
     return None
 
+  fqdn = config['hostname']
+  if config['domain_name']:
+    fqdn += '.' + config['domain_name']
+
+  os.system("hostnamectl set-hostname --static {0}".format(fqdn))
+
+  # Restart services that use the hostname
+  os.system("systemctl restart rsyslog.service")
+
+  # If SNMP is running, restart it too
+  if os.system("pgrep snmpd > /dev/null") == 0:
+    os.system("systemctl restart snmpd.service")
+  
+  # restart pdns if it is used
+  if os.system("/usr/bin/rec_control ping >/dev/null 2>&1") == 0:
+    os.system("/etc/init.d/pdns-recursor restart >/dev/null")
+
+  return None
 
 if __name__ == '__main__':
-    try:
-        c = get_config()
-        verify(c)
-        generate(c)
-        apply(c)
-    except ConfigError as e:
-        print(e)
-        sys.exit(1)
+  try:
+    c = get_config()
+    verify(c)
+    generate(c)
+    apply(c)
+  except ConfigError as e:
+    print(e)
+    sys.exit(1)
-- 
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