#!/usr/bin/python3

#    pYSFReflector
#
#    Created by Antonio Matraia (IU5JAE) on 20/02/2021.
#    Copyright 2021 Antonio Matraia (IU5JAE). All rights reserved.

#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program 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 General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.


import socket
import threading
import queue
import sys
import os
import time
import re
import configparser
import signal
from datetime import datetime
import bisect 
import struct


def ip2long(ip):
    packed = socket.inet_aton(ip)
    lng = struct.unpack("!L", packed)[0]
    return lng


def long2ip(lng):
    packed = struct.pack("!L", lng)
    ip = socket.inet_ntoa(packed)
    return ip


## LH list management ##
def inserisci_lista(lista, elemento, n_max):
    if (len(lista) < n_max):
        lista.append(elemento)
    else:
        for i in range(n_max - 1):
            lista[i] = lista[i+1]
        lista[n_max-1] = elemento    

def inserisci_listaD(lista, elemento, n_max):    
    for i in lista:
      if (i[1] == elemento[1]):
        lista.remove(i)
        break
    
    if (len(lista) < n_max):
        lista.append(elemento)
    else:
        for i in range(n_max - 1):
            lista[i] = lista[i+1]
        lista[n_max-1] = elemento    



def stampa_lista(lista):
  for i in range(len(lista)):
      print(lista[len(lista)-i-1])

#################################

def inlist(a, x):
    i = bisect.bisect_left(a, x)
    if i != len(a) and a[i] == x:
        return True
    else:
        return False        

def check_string(l):
  s = ''
  for c in l:
     if ((not c.isprintable()) and (ord(c) != 10)):
       s += '<' +str(ord(c))  + '>' 
     if c.isprintable():
       s += c  
  return s


def RecvData(sock,recvPackets):
    while True:
        data,addr = sock.recvfrom(1024)    # block if I don't receive anything 
        recvPackets.put((data,addr))
        

def CalcID(ref):
  c = ref.strip().ljust(16)
  u = 0

  for a in c:
    u = (u + ord(a)) & 0xFFFFFFFF
    u = (u + (u << 10) & 0xFFFFFFFF) & 0xFFFFFFFF
    u = (u ^ (u >> 6)) & 0xFFFFFFFF

  u = (u + (u << 3) & 0xFFFFFFFF) & 0xFFFFFFFF
  u = (u ^ (u >> 11))& 0xFFFFFFFF
  u = (u + (u << 15)& 0xFFFFFFFF)& 0xFFFFFFFF

  u = u % 100000
  return u


def getidgw(cl, adr):
  i=[0, '']
  for c in cl:       
    if ((c[0] == adr[0]) and (c[1] == adr[1])): 
      i = [c[4], c[2]]
      break
  return i

        
def ElencoNodi(cl):
  while True:
    time.sleep(120)
    cl_lo = []
    if (len(cl) == 0):
      printlog('No repeaters/gateways linked')
    else:
      printlog('Currently linked repeaters/gateways:')
      for c in cl:
        printlog('     ' + c[2].ljust(10) + ': ' + str(c[0]) + ':' + str(c[1]) + ' ' + str(c[3]) + '/60')
        if (c[5] == 1):
          cl_lo.append(c)
      if (len(cl_lo) == 0):
        printlog('No repeaters/gateways muted')
      else:
        printlog('Currently muted repeaters/gateways:')
        for c in cl_lo:
          printlog('     ' + c[2].ljust(10) + ': ' + str(c[0]) + ':' + str(c[1]) + ' ' + str(c[3]) + '/60')     


def TimeoutNodi(cl):
  while True:
    time.sleep(1)
    for c in cl:
      c[3] += 1
      if (c[3] > 60):
        printlog('Removing ' + c[2].ljust(10) + ' (' + c[0] + ':' + str(c[1]) + ') disappeared')
        cl.remove(c)


def TimeoutTX(t, t_lock, r_lock, lista_lh, lista_lhd):
  while True:
    if (t[1] < 5):
      t[1] += 0.1
    if ((t[1] > 1.0) and (t[0] != 0)):
      t[0] = 0  
      printlog('Network watchdog has expired')
      inserisci_lista(lista_lh, [check_string(t[2]), check_string(t[3]), check_string(t[4]), t[5], datetime.fromtimestamp(t[6]).strftime("%d-%m-%Y %H-%M-%S"), round(time.time() - t[6]) ], 20)
      inserisci_listaD(lista_lhd, [check_string(t[2]), check_string(t[3]), check_string(t[4]), t[5], datetime.fromtimestamp(t[6]).strftime("%d-%m-%Y %H-%M-%S"), round(time.time() - t[6]) ], 20)
      t[1] = 0
      t[2] = ''
      t[3] = ''
      t[4] = ''
      t[5] = 0
      t[6] = 0
    pop_list = []  
    for d in t_lock:
      if (t_lock[d] < 5):
        t_lock[d] += 0.1
      if ((t_lock[d] > 1.5) and (t_lock[d] != 0)):    
        pop_list.append(d)
        r_lock.remove(d)
        
    for x in pop_list:
        t_lock.pop(x)   
        printlog('Removed from blockeds queue ' + str(x))
    time.sleep(0.1)  


def canTrasmit(cs, re_en):
  global BLACK_LIST
  global WHITE_LIST
  call_sp = re.split(r'[-/]', cs)
  call = call_sp[0]
  
## always block a stream from repeater ###
  if (len(call_sp) > 1):
    if (call_sp[1] == 'RPT'):
      return False      
      
## case CheckRE == 1 ###
  if (re_en == 1):  
    if inlist(WHITE_LIST, call):
      return True
    if inlist(BLACK_LIST, call):
      return False
    if (re.match(r'^\d?[A-Z]{1,2}\d{1,4}[A-Z]{1,3}$',call,re.IGNORECASE) and (len(call) <= 8)):
      return True
    else:
      return False  

## case CheckRE == 0 ###
  if (re_en == 0):  
    if inlist(WHITE_LIST, call):
      return True
    if inlist(BLACK_LIST, call):
      return False
    return True

## case CheckRE == -1 ###
  if (re_en == -1):  
    if inlist(BLACK_LIST, call):
      return False
    if inlist(WHITE_LIST, call):
      return True
    return False
    
    
def lista_gw(cl):
  info = ''
  for c in cl:
    info += c[2] + ':' + c[0] + ':' + str(c[1]) + ';'  
  return info


def lista_invio(lista):
  info = ''
  for i in range(len(lista)):
    info += lista[len(lista)-i-1][0] + ':' + lista[len(lista)-i-1][1] + ':' + lista[len(lista)-i-1][2] + ':' + str(lista[len(lista)-i-1][3]) + ':' + lista[len(lista)-i-1][4] + ':' + str(lista[len(lista)-i-1][5]) + ';'  
  return info      


def update_clients(cl):
  global GW_BL
  global IP_BL  
  for c in cl:
    if (inlist(GW_BL, c[2]) or inlist(IP_BL, ip2long(c[0]))):
      c[5] = 1
    else:  
      c[5] = 0


def blacklist(f_bl, t_reload, cli):
  global BLACK_LIST
  global WHITE_LIST
  global GW_BL
  global IP_BL
  f_time_old = 0
  try:
    f_time = os.stat(f_bl).st_mtime
  except:
    pass
    
  while True:
    f_time = os.stat(f_bl).st_mtime
    if (f_time != f_time_old):
      try:
        file = open(f_bl)
        BL_TMP = []
        GW_TMP = []
        IP_TMP = []
        WL_TMP = []
        printlog('Reload the Blacklist from File')
        for row in file:
          content = row.strip()
          
          # valid line (not a comment)
          if ((len(content) > 3) and (content[0] != '#')):
            c_split = content.split(':')
            for i in range(len(c_split)):
              c_split[i] = c_split[i].strip()
              
            # CALL
            if (len(c_split) == 1 or c_split[0] == 'CS'):
              if (len(c_split) == 1):
                cont = content
              if (c_split[0] == 'CS'):
                cont = c_split[1] 
              if ((len(cont) <= 8) and (len(cont) >= 3)):
                if (not inlist(BL_TMP, cont)):
                  bisect.insort(BL_TMP,cont)
            
            # WL      
            if (len(c_split) == 2 and c_split[0] == 'AL'):      
              if (not inlist(WL_TMP, c_split[1])):
                bisect.insort(WL_TMP,c_split[1])
                  
            # GW      
            if (len(c_split) == 2 and c_split[0] == 'GW'):      
              if (not inlist(GW_TMP, c_split[1])):
                bisect.insort(GW_TMP,c_split[1])
                
            # IP      
            if (len(c_split) == 2 and c_split[0] == 'IP'):      
              try:
                ipa = socket.gethostbyname(c_split[1])
                ipl = ip2long(ipa)
              except:
                ipl = 0
                printlog('Invalid hostname ' + c_split[1])
              if (ipl > 0):  
                if (not inlist(IP_TMP, ipl)):
                  bisect.insort(IP_TMP, ipl)
                          
        file.close() 
      except Exception as ex:
        printlog('Failed to load Blacklist from File ' + str(ex) )
      BLACK_LIST = BL_TMP.copy()
      WHITE_LIST = WL_TMP.copy()
      GW_BL = GW_TMP.copy()
      IP_BL = IP_TMP.copy()
      printlog('Loaded ' + str(len(BLACK_LIST)) + '/CS ' + str(len(WHITE_LIST)) + '/AL ' + str(len(GW_BL)) + '/GW ' + str(len(IP_BL)) + '/IP')
      f_time_old = f_time
      update_clients(cli)
    else:
      pass
    time.sleep(t_reload)


## reading configuration file ##
def ReadConfig(f,p):
  config = configparser.ConfigParser()
  
  config_file = f.strip()
  config.read(config_file)
  name = config['Info']['Name'] 
  description = config['Info']['Description']
  try:
    id = int(config['Info']['id'])
  except:
    id = 0
  log_path = config['Log']['FilePath']
  log_name = config['Log']['FileRoot']
  try:
    file_rotate = config['Log']['FileRotate']
  except:
    file_rotate = "1" # to keep file-rotation by default with timestamp

  try:
    en_ext_cmd = int(config['Log']['EnableExtendedCommands'])
  except:
    en_ext_cmd = 0 # extended commands disabled by default


  
  try:
    port = int(config['Network']['Port'])
  except:
    port = 42000
  try:  
    file_blacklist = config['Block List']['File']
  except:
    file_blacklist = ''

  try:  
    CheckRE = int(config['Block List']['CheckRE'])
    if (CheckRE > 1):
      CheckRE = 1
    if (CheckRE < -1):
      CheckRE = -1
  except:
    CheckRE = 1
  
  try:
    t_reload_blacklist = float(config['Block List']['Time'])
  except:
    t_reload_blacklist = 5.0
  if (t_reload_blacklist < 0.1):
    t_reload_blacklist = 0.1
    
  p.append(id)                 # 0
  p.append(name)               # 1
  p.append(description)        # 2
  p.append(log_path)           # 3
  p.append(log_name)           # 4
  p.append(port)               # 5
  p.append(file_blacklist)     # 6
  p.append(t_reload_blacklist) # 7
  p.append(file_rotate)        # 8
  p.append(CheckRE)            # 9
  p.append(en_ext_cmd)         #10


    
def sanitize_msg(data):
  bya_msg = bytearray(data)

  if ((data[0:4] == b"YSFP") and (len(data) == 14)):
    for i in range(10):
      if (bya_msg[i+4] == 0):
        bya_msg[i+4] = 32      

  if ((data[0:4] == b"YSFD") and (len(data) == 155)):
    for i in range(30):
      if (bya_msg[i+4] == 0):
        bya_msg[i+4] = 32

  return(bytes(bya_msg))
  
    
def RunServer(config):
    global filelog
    global version
    global BLACK_LIST
    global GW_BL
    global IP_BL
    host = '0.0.0.0'   
    port = config[5]
    s = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
    s.setblocking(1)
    s.bind((host,port))
    clients = []   # addr, port, gw, t_corr, ID, lonly
    c = []
    rx_lock = []
    rx_lock_tout = {}
    
    # LH list
    LH = []
    LHD = []
    
    # muted list
    BL = []
    BLD = []
        
    id = 1  # id gw
    id_str = 1 # id stream
    tx = [0, 0, '', '', '', 0, 0]  # id_gw, tout, gateway, src, dest, id_stream, start_time
    
    refl_name = config[1]
    refl_desc = config[2]
    
    if ((config[0] > 0) and (config[0] < 1000000)):
      refl_id = str(config[0]).zfill(5)
    else:  
      refl_id = CalcID(refl_name)
    
    f_blacklist = config[6]
    tr_blacklist = config[7] * 60.0
    
    CheckRE = config[9]
    
    en_ext_cmd = config[10]
    
    recvPackets = queue.Queue()

    print('Starting pYSFReflector-' + version)
    printlog('Starting pYSFReflector-' + version)
    if (en_ext_cmd == 1):
      printlog('Extended Commands Enabled')
    else:
      printlog('Extended Commands Disabled')  
    threading.Thread(target=RecvData,args=(s,recvPackets)).start()
    threading.Thread(target=ElencoNodi,args=(clients,)).start()
    threading.Thread(target=TimeoutNodi,args=(clients,)).start()
    threading.Thread(target=TimeoutTX,args=(tx,rx_lock_tout,rx_lock,LH,LHD)).start()
    if (len(f_blacklist) > 0):
      threading.Thread(target=blacklist,args=(f_blacklist,tr_blacklist,clients)).start()
    
    time_start = time.time()
    
    
    while True:
            data_ns, addr = recvPackets.get()    # blocked if queue is empty
            data = sanitize_msg(data_ns)
            cmd = data[0:4]
            if (cmd == b'YSFP'):
              pres = False
              for c in clients:
                if ((c[0] == addr[0]) and (c[1] == addr[1])):
                  pres = True
                  c[3] = 0
                  break
              if not pres:  
                lonly = 0
                if inlist(GW_BL, (data[4:14]).decode().strip()):
                  lonly = 1
                if inlist(IP_BL, ip2long(addr[0])):
                  lonly = 1 
                c=[addr[0], addr[1], (data[4:14]).decode().strip(), 0, id, lonly]
                id += 1
                clients.append(c)
                printlog('Adding ' + c[2].ljust(10) + ' (' + c[0] + ':' + str(c[1]) + ')')
              s.sendto(b'YSFPREFLECTOR ',addr)
           
            if (cmd == b'YSFU'):
               for c in clients:
                if ((c[0] == addr[0]) and (c[1] == addr[1])):
                  printlog('Removing ' + c[2].ljust(10) + ' (' + c[0] + ':' + str(c[1]) + ') unlinked')
                  clients.remove(c)
                  break
              
            if ((cmd == b'YSFD') and (len(data) == 155)):
              [id_corr, gw_corr] = getidgw(clients, addr)
              if (tx[0] == 0):
                if inlist(GW_BL, gw_corr):
                  tx_ok = False
                  block_r = 'GW'
                else:
                  if inlist(IP_BL, ip2long(addr[0])):
                    tx_ok = False
                    block_r = 'IP'      
                  else:
                    tx_ok = canTrasmit(data[14:24].decode().strip(), CheckRE)
                    block_r = 'CS'
              if tx_ok:
                if ((tx[0] == 0) and (id_corr != 0)): 
                  tx[0] = id_corr
                  # gateway
                  tx[2] = data[4:14].decode().strip()
                  # src
                  tx[3] = data[14:24].decode().strip()
                  # dest
                  tx[4] = data[24:34].decode().strip() 
                  # stream ID
                  tx[5] = id_str
                  # time start
                  tx[6] = time.time()
                  id_str += 1   
                  printlog('Received data from ' + tx[3].ljust(10) +   ' to ' +  tx[4].ljust(10) + ' at ' +  tx[2].ljust(10))
                  
              else:
                if (id_corr not in rx_lock):
                  rx_lock.append(id_corr)  
                  inserisci_lista(BL, [check_string(data[4:14].decode().strip()) + '/' + block_r, check_string(data[14:24].decode().strip()), check_string(data[24:34].decode().strip()), -1, datetime.fromtimestamp(time.time()).strftime("%d-%m-%Y %H-%M-%S"), -1 ], 20)
                  inserisci_listaD(BLD, [check_string(data[4:14].decode().strip()) + '/' + block_r, check_string(data[14:24].decode().strip()), check_string(data[24:34].decode().strip()), -1, datetime.fromtimestamp(time.time()).strftime("%d-%m-%Y %H-%M-%S"), -1 ], 20)
                  printlog('Data from ' + data[14:24].decode().strip().ljust(10) + ' at ' + data[4:14].decode().strip().ljust(10) + ' blocked/' + block_r)
                rx_lock_tout[id_corr] = 0  
              
              if ((id_corr == tx[0]) and (id_corr != 0)):    
                tx[1] = 0
        
              for c in clients:
                if (((c[0] != addr[0]) or (c[1] != addr[1])) and (id_corr == tx[0]) and (id_corr != 0) and (id_corr not in rx_lock)):
                  s.sendto(data,(c[0], c[1]))
            
              if ((data[34] & 0x01) == 0x01):
                if (tx[0] != 0):
                  printlog('Received end of transmission')
                  inserisci_lista(LH, [check_string(tx[2]), check_string(tx[3]), check_string(tx[4]), tx[5], datetime.fromtimestamp(tx[6]).strftime("%d-%m-%Y %H-%M-%S"), round(time.time() - tx[6]) ], 20)
                  inserisci_listaD(LHD, [check_string(tx[2]), check_string(tx[3]), check_string(tx[4]), tx[5], datetime.fromtimestamp(tx[6]).strftime("%d-%m-%Y %H-%M-%S"), round(time.time() - tx[6]) ], 20)
                tx[0] = 0
                tx[2] = ''
                tx[3] = ''
                tx[4] = ''
                tx[5] = 0
                tx[6] = 0
                  
            if (cmd == b'YSFS'):
              printlog('YSF server status enquiry from ' + addr[0] + ':' + str(addr[1]))
              if (len(clients) > 999):
                num_cli = 999
              else:
                num_cli = len(clients)  
              info = 'YSFS' + str(refl_id).zfill(5) + refl_name.ljust(16) + refl_desc.ljust(14) + str(num_cli).zfill(3)
              s.sendto(str.encode(info),addr)  

                  
            if (cmd == b'YSFV'):
              printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
              info = 'YSFV' + 'pYSFReflector' + ' ' + version
              s.sendto(str.encode(info),addr)  
 
            if (cmd == b'YSFI'):
              printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
             # info = 'YSFV' + 'pYSFReflector' + ' ' + version
             # s.sendto(str.encode(info),addr)  
                         
                        
            
            ## Extended Commands ##
            if (en_ext_cmd == 1):
              if (cmd == b'QSRU'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'ASRU;' + str(round(time.time()-time_start)) + ';'
                s.sendto(str.encode(info),addr) 
                    
              if (cmd == b'QSRI'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'ASRI;' + str(refl_id) + ':' + refl_name + ':' + refl_desc + ':' + 'pYSFReflector' + ':' + version + ':' + str(CheckRE) + ';'
                s.sendto(str.encode(info),addr) 
            
              if (cmd == b'QGWL'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'AGWL;' + lista_gw(clients) 
                s.sendto(str.encode(info),addr) 
               
              if (cmd == b'QLHL'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'ALHL;' + lista_invio(LH) 
                s.sendto(str.encode(info),addr)    

              if (cmd == b'QREJ'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'AREJ;' + lista_invio(BL) 
                s.sendto(str.encode(info),addr)        
               
              if (cmd == b'QLHD'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'ALHD;' + lista_invio(LHD) 
                s.sendto(str.encode(info),addr)    

              if (cmd == b'QRED'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                info = 'ARED;' + lista_invio(BLD) 
                s.sendto(str.encode(info),addr)        

              if (cmd == b'QACL'):
                printlog('Received command ' + cmd.decode() + ' from: ' + addr[0] + ':' + str(addr[1]))
                s_info = ''
                info = 'AACL;CS/' + str(len(BLACK_LIST)) + '|' + 'AL/' + str(len(WHITE_LIST)) + '|' +  'GW/' + str(len(GW_BL)) + '|' +  'IP/' + str(len(IP_BL)) + ';'
                i = 0
                for c in BLACK_LIST:
                  s_info += 'CS:' + c + ';'
                  i += 1
                  if (i >= 20):
                    break
                info += s_info 
               
                s_info = ''
                i = 0
                for c in WHITE_LIST:
                  s_info += 'AL:' + c + ';'
                  i += 1
                  if (i >= 20):
                    break
                info += s_info 
               
                s_info = ''
                i = 0
                for c in GW_BL:
                  s_info += 'GW:' + c + ';'
                  i += 1
                  if (i >= 20):
                    break
                info += s_info  
               
                s_info = ''
                i = 0
                for c in IP_BL:
                  s_info += 'IP:' + long2ip(c) + ';'
                  i += 1
                  if (i >= 20):
                    break
                info += s_info   
               
                s.sendto(str.encode(info),addr)                     
            
                                
    s.close()

      
def printlog(mess):
  global filelog
  global log_basename
  global file_rotate
  if file_rotate == "1":
    log_file = log_basename + '-' + str(datetime.utcnow().strftime('%Y-%m-%d')) + '.log'
  else:
    log_file = log_basename + '.log'
  try:
    if not os.path.isfile(log_file):
      filelog.flush()
      filelog.close()
      filelog = open(log_file,'x')
  except:
    pass     
  str_log = check_string('M: ' + str(datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f'))[:-3] + ' ' + mess) 
  try:
    filelog.write(str_log + '\n') 
    filelog.flush()
  except:
    pass  


######## main ########

version = '20210329'

if (len(sys.argv) != 2):
  print('Invalid Number of Arguments')
  print('use: YSFReflector <configuration file>')
  sys.exit()
  
if (sys.argv[1].strip() == '-v'):
  print('pYSFReflector version ' + version)
  sys.exit()

## reading configuration ##
config=[]
try:
  ReadConfig(sys.argv[1].strip(), config)
except:
  print('Unable to read configuration file')
  sys.exit()
  
log_basename = config[3] + '/' + config[4]
file_rotate = config[8]
### log
if file_rotate == "1":
  log_file = log_basename + '-' + str(datetime.utcnow().strftime('%Y-%m-%d')) + '.log'
else:
  log_file = log_basename + '.log'
try:
  if os.path.isfile(log_file):
    filelog = open(log_file,'a')
  else:
    filelog = open(log_file,'x')
except:
  print('Unable to Open Log File')
  sys.exit()
  
BLACK_LIST = [] 
WHITE_LIST = [] 
GW_BL = []
IP_BL = []  
  
RunServer(config)