T1174: migrate local hostname/DNS handling to vyos-1x

1 files changed, 104 insertions, 40 deletions

diff --git a/src/conf_mode/host_name.py b/src/conf_mode/host_name.py
index 030735215..4b6ce76b0 100755
--- a/src/conf_mode/host_name.py
+++ b/src/conf_mode/host_name.py
@@ -24,81 +24,146 @@ 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
+"""
+
+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 []
+
+default_config_data = {
+    'hostname': 'vyos',
+    'domain_name': '',
+    'domain_search': [],
+    'nameserver': [],
+    'no_dhcp_ns': False
+}
 
 def get_config():
     """Get configuration"""
     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
-
-    return {"hostname": hostname, "domain": domain, "fqdn": fqdn}
+    hosts['domain_search'] = conf.return_values("system domain-search domain")
+    hosts['nameserver'] = conf.return_values("system name-server")
+    hosts['no_dhcp_ns'] = conf.exists('system disable-dhcp-nameservers')
 
+    return hosts
 
 def verify(config):
     """Verify configuration"""
     # check for invalid host
 
     # pattern $VAR(@) "^[[:alnum:]][-.[:alnum:]]*[[:alnum:]]$" ; "invalid host name $VAR(@)"
-    if not hostname_regex.match(config["hostname"]):
+    hostname_regex = re.compile("^[A-Za-z0-9][-.A-Za-z0-9]*[A-Za-z0-9]$")
+    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"])
+    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')
+
+    return None
 
 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)
+    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)
+
+    if not config['no_dhcp_ns']:
+        config['nameserver'] += dhcp_ns
+
+    tmpl = jinja2.Template(config_tmpl_hosts)
+    config_text = tmpl.render(config)
+    with open(config_file_hosts, 'w') as f:
+        f.write(config_text)
+
+    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):
     """Apply configuration"""
-    os.system("hostnamectl set-hostname --static {0}".format(config["fqdn"]))
+    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")
@@ -109,7 +174,6 @@ def apply(config):
 
     return None
 
-
 if __name__ == '__main__':
     try:
         c = get_config()