#!/usr/bin/python3

# Copyright 2019 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library.  If not, see <http://www.gnu.org/licenses/>.

import sys
import os
import json
import socket
import subprocess

dhclient_conf_dir = r'/var/lib/dhcp/dhclient_'

class Interface():
  def __init__(self, ifname=None, type=None):
    if not ifname:
      raise Exception("interface name required")
    if not os.path.exists('/sys/class/net/{0}'.format(ifname)) and not type:
      raise Exception("interface {0} not found".format(str(ifname)))  
    else:
      if not os.path.exists('/sys/class/net/{0}'.format(ifname)):
        try:
          ret = subprocess.check_output(['ip link add dev ' + str(ifname) + ' type ' + type], stderr=subprocess.STDOUT, shell=True).decode()
        except subprocess.CalledProcessError as e:
          if self._debug():
            self._debug(e)
          if "Operation not supported" in str(e.output.decode()):
            print(str(e.output.decode()))
            sys.exit(0)

    self.ifname = str(ifname)

  def _debug(self, e=None):
    """ 
        export DEBUG=1 to see debug messages
    """
    if os.getenv('DEBUG') == '1':
      if e:
        print ("Exception raised:\ncommand: {0}\nerror code: {1}\nsubprocess output: {2}".format(e.cmd, e.returncode, e.output.decode()) ) 
      return True
    return False


  def set_alias(self, alias=None):
    if not alias:
      open('/sys/class/net/{0}/ifalias'.format(self.ifname),'w').write(self.ifname)
    else:
      open('/sys/class/net/{0}/ifalias'.format(self.ifname),'w').write(str(alias))

  def get_alias(self):
    return open('/sys/class/net/{0}/ifalias'.format(self.ifname),'r').read()

  def del_alias(self):
    open('/sys/class/net/{0}/ifalias'.format(self.ifname),'w').write()  


  def set_link_state(self, state="up"):
    if state.lower() == 'up' or state.lower() == 'down':
      try:
        ret = subprocess.check_output(['ip link set dev ' + self.ifname + ' ' + state], shell=True).decode()
        return 0 
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
        return 1 
    else:
      raise ValueError("value can only be up or down")

  def get_link_state(self):
    """
        returns either up/down or None if it can't find the state
    """
    try:
      ret = subprocess.check_output(['ip -j link show ' + self.ifname], shell=True).decode()
      s = json.loads(ret)
      return s[0]['operstate'].lower()
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None


  def remove_interface(self):
    try:
      ret = subprocess.check_output(['ip link del dev ' + self.ifname], shell=True).decode()
      return 0
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None


  def set_macaddr(self, mac=None):
    # ip will give us an error if the mac is invalid
    try:
      ret = subprocess.check_output(['ip link set address ' + mac + ' ' + self.ifname], shell=True).decode()
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None

  def get_macaddr(self):
    try:
      ret = subprocess.check_output(['ip -j -4 link show dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      j = json.loads(ret)
      return j[0]['address']
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None


  def get_ipv4_addr(self):
    """
        reads all IPs assigned to an interface and returns it in a list, 
        or None if no IP address is assigned to the interface
    """
    ips = []
    try:
      ret = subprocess.check_output(['ip -j -4 addr show dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      j = json.loads(ret)
      for i in j:
        if len(i) != 0:
          for addr in i['addr_info']:
            ips.append(addr['local'])
      return ips
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None


  def get_ipv6_addr(self):
    """
        reads all IPs assigned to an interface and returns it in a list,
        or None if no IP address is assigned to the interface
    """
    ips = []
    try:
      ret = subprocess.check_output(['ip -j -6 addr show dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      j = json.loads(ret)
      for i in j:
        if len(i) != 0:
          for addr in i['addr_info']:
            ips.append(addr['local'])
      return ips
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None


  def add_ipv4_addr(self, ipaddr=[]):
    """
        add addresses on the interface
    """
    for ip in ipaddr:
      try:
        ret = subprocess.check_output(['ip -4 address add ' + ip + ' dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
        return None
    return True


  def del_ipv4_addr(self, ipaddr=[]):
    """
        delete addresses on the interface
    """
    for ip in ipaddr:
      try:
        ret = subprocess.check_output(['ip -4 address del ' + ip + ' dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
        return None
    return True


  def add_ipv6_addr(self, ipaddr=[]):
    """
        add addresses on the interface
    """
    for ip in ipaddr:
      try:
        ret = subprocess.check_output(['ip -6 address add ' + ip + ' dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
        return None
    return True


  def del_ipv6_addr(self, ipaddr=[]):
    """
        delete addresses on the interface
    """
    for ip in ipaddr:
      try:
        ret = subprocess.check_output(['ip -6 address del ' + ip + ' dev ' + self.ifname], stderr=subprocess.STDOUT, shell=True).decode()
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
        return None
    return True


  def get_mtu(self):
    try:
      ret = subprocess.check_output(['ip -j link list dev ' + self.ifname], shell=True).decode()
      a = json.loads(ret)[0]
      return a['mtu']
    except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
        return None

  def set_mtu(self, mtu=None):
    if not mtu:
      return None
    try:
      ret = subprocess.check_output(['ip link set mtu ' + str(mtu) + ' dev ' + self.ifname], shell=True).decode()
      return True
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None


  #### replace dhcpv4/v6 with systemd.networkd?
  def set_dhcpv4(self):
    conf_file = dhclient_conf_dir + self.ifname + '.conf'
    pidfile   = dhclient_conf_dir + self.ifname + '.pid'
    leasefile = dhclient_conf_dir + self.ifname + '.leases'

    a = [ 
          '# generated by interface_config.py',
          'option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;',
          'interface \"' + self.ifname + '\" {',
          '\tsend host-name \"' + socket.gethostname() +'\";',
          '\trequest subnet-mask, broadcast-address, routers, domain-name-servers, rfc3442-classless-static-routes, domain-name, interface-mtu;',
          '}' 
        ]

    cnf = ""
    for ln in a:
      cnf +=str(ln + "\n")
    open(conf_file, 'w').write(cnf)
    if os.path.exists(dhclient_conf_dir + self.ifname + '.pid'):
      try:
        ret = subprocess.check_output(['/sbin/dhclient -4 -r -pf ' + pidfile], shell=True).decode()
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
    try:
      ret = subprocess.check_output(['/sbin/dhclient -4 -q -nw -cf ' + conf_file + ' -pf ' + pidfile + ' -lf ' + leasefile + ' ' + self.ifname], shell=True).decode()
      return True
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None

  def del_dhcpv4(self):
    conf_file = dhclient_conf_dir + self.ifname + '.conf'
    pidfile   = dhclient_conf_dir + self.ifname + '.pid'
    leasefile = dhclient_conf_dir + self.ifname + '.leases'
    if not os.path.exists(pidfile):
      return 1 
    try:
      ret = subprocess.check_output(['/sbin/dhclient -4 -r -pf ' + pidfile], shell=True).decode()
      return True
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None

  def get_dhcpv4(self):
    pidfile = dhclient_conf_dir + self.ifname + '.pid'
    if not os.path.exists(pidfile):
      print ("no dhcp client running on interface {0}".format(self.ifname))
      return False
    else:
      pid = open(pidfile, 'r').read()
      print("dhclient running on {0} with pid {1}".format(self.ifname, pid))
      return True


  def set_dhcpv6(self):
    conf_file = dhclient_conf_dir +  self.ifname + '.v6conf'
    pidfile   = dhclient_conf_dir + self.ifname + '.v6pid'
    leasefile = dhclient_conf_dir + self.ifname + '.v6leases'
    a = [
          '# generated by interface_config.py',
          'interface \"' + self.ifname + '\" {',
          '\trequest routers, domain-name-servers, domain-name;',
          '}'
        ]
    cnf = ""
    for ln in a:
      cnf +=str(ln + "\n")
    open(conf_file, 'w').write(cnf)
    subprocess.call(['sysctl', '-q', '-w', 'net.ipv6.conf.' + self.ifname + '.accept_ra=0'])
    if os.path.exists(pidfile):
      try:
        ret = subprocess.check_output(['/sbin/dhclient -6 -q -x -pf ' + pidfile], shell=True).decode()
      except subprocess.CalledProcessError as e:
        if self._debug():
          self._debug(e)
    try:
      ret = subprocess.check_output(['/sbin/dhclient -6 -q -nw -cf ' + conf_file + ' -pf ' + pidfile + ' -lf ' + leasefile + ' ' + self.ifname], shell=True).decode()
      return True
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None

  def del_dhcpv6(self):
    conf_file = dhclient_conf_dir +  self.ifname + '.v6conf'
    pidfile   = dhclient_conf_dir + self.ifname + '.v6pid'
    leasefile = dhclient_conf_dir + self.ifname + '.v6leases'
    if not os.path.exists(pidfile):
      return 1
    try:
      ret = subprocess.check_output(['/sbin/dhclient -6 -q -x -pf ' + pidfile], shell=True).decode()
      subprocess.call(['sysctl', '-q', '-w', 'net.ipv6.conf.' + self.ifname + '.accept_ra=1'])
      return True
    except subprocess.CalledProcessError as e:
      if self._debug():
        self._debug(e)
      return None

  def get_dhcpv6(self):
    pidfile = dhclient_conf_dir + self.ifname + '.v6pid'
    if not os.path.exists(pidfile):
      print ("no dhcpv6 client running on interface {0}".format(self.ifname))
      return False
    else:
      pid = open(pidfile, 'r').read()
      print("dhclientv6 running on {0} with pid {1}".format(self.ifname, pid))
      return True


#### TODO: dhcpv6-pd via dhclient