#!/usr/bin/env python3

from systemd import journal
from datetime import datetime, timedelta
import re           # read lines
# Import smtplib for the actual sending function
import smtplib
# Import the email modules we'll need
from email.message import EmailMessage
from tabulate import tabulate
import GeoIP
import os
import socket
import logging
import logging.config

class connection:
    def __init__(self,logger):
        self.logger = logger
        self.attempts = {}
        self.gi = GeoIP.open("/usr/share/GeoIP/GeoIP.dat", GeoIP.GEOIP_STANDARD)

    def __add(self,hostname: str,user: str, pattern: str):
        self.logger.debug("<<< attempts:{}".format(self.attempts))
        self.logger.debug("--- add {} {} {}".format(hostname,user,pattern))
        if hostname in self.attempts:
            if user in self.attempts[hostname]:
                if pattern in self.attempts[hostname][user]:
                    self.attempts[hostname][user][pattern] += 1
                else:
                    self.attempts[hostname][user][pattern] = 1
            else:
                self.attempts[hostname][user] = { pattern: 1 }
        else:
            self.attempts[hostname] = { user: { pattern: 1 } }
        self.logger.debug(">>> attempts:{}".format(self.attempts))

    def __get_list(self):
        liste = []
        for h,v1 in self.attempts.items():
            self.logger.debug("h {}".format(h))
            gcn = self.gi.country_name_by_addr(h)
            if gcn is not None:
                g = gcn
            else:
                g = "localhost"
            for u,v2 in v1.items():
                self.logger.debug("u {}".format(u))
                for s,n in v2.items():
                    self.logger.debug("s {}".format(s))
                    self.logger.debug("g {} h {} u {} s {} n {}".format(g,h,u,s,n))
                    liste.append([g,h,u,s,n])
                    self.logger.debug(liste)
        return liste

    def report(self):
        headers = { 'Country':'', 'Hostname':'', 'User':'', 'Source':'', 'Number':'' }
        header = headers.keys()
        msg = EmailMessage()
        msg.set_content(tabulate(self.__get_list(),headers))
        msg['Subject'] = f'[ssh][attempts] Reporting'
        msg['From'] = "{}@{}".format(os.getlogin(),socket.gethostname())
        msg['To'] = "{}@{}".format(os.getlogin(),'192.168.0.238')
        self.logger.debug(msg)
        s = smtplib.SMTP('localhost')
        s.send_message(msg)
        s.quit()

    def addmessage(self, message:str):
        patterns = {
            'pam_unix':r'''^pam_unix[^ ]*[ ](?P<status>[a-z ]+)[; ]+logname=[.]*[ ]uid=[0-9]+[ ]euid=[0-9]+[ ]tty=[sh]+[ ]ruser=[.]*[ ]rhost=(?P<hostname>[0-9.]+)[ ]+user=(?P<user>[a-zA-Z0-9]+)$''',
            'failed':r'''^Failed[ ]password[ ]for[ ]+(?P<user>[a-zA-Z0-9]+)[ ]from[ ](?P<hostname>[0-9.]+)[ ]port[ ][0-9]+[ ](?P<protocol>[a-z0-9]+)$''',
            'invalid':r'''^Failed[ ]password[ ]for[ ]invalid[ ]user[ ]+(?P<user>[a-zA-Z0-9]+)[ ]from[ ](?P<hostname>[0-9.]+)[ ]port[ ][0-9]+[ ](?P<protocol>[a-z0-9]+)$''',
            'closed':r'''^Connection[ ]closed[ ]by[ ]authenticating[ ]user[ ](?P<user>[a-zA-Z0-9]+)[ ](?P<hostname>[0-9.]+)[ ]port[ ][0-9]+[ ](?P<step>[a-z\[\]]+)$''',
            'reset':r'''^Connection[ ]reset[ ]by[ ]invalid[ ]user[ ](?P<user>[a-zA-Z0-9]+)[ ](?P<hostname>[0-9.]+)[ ]port[ ][0-9]+[ ](?P<step>[a-z\[\]]+)$''',
            'pam':r'''^PAM[ ][0-9][ ]more[ ]authentication[ ]failures;[ ]logname=[ ]uid=[0-9]+[ ]euid=[0-9]+[ ]tty=ssh[ ]ruser=[ ]rhost=(?P<hostname>[0-9.]+)[ ]+user=(?P<user>[a-zA-Z0-9]+)$''',
            'pamano':r'''^PAM[ ][0-9][ ]more[ ]authentication[ ]failures;[ ]logname=[ ]uid=[0-9]+[ ]euid=[0-9]+[ ]tty=ssh[ ]ruser=[ ]rhost=(?P<hostname>[0-9.]+)([ ]+user=(?P<user>[a-zA-Z0-9]+|)|)$''',
            'stopping':r'''^Received[ ]signal[ ]15;[ ]terminating.$''',
            'ignoring':r'''^PAM[ ]service[(]sshd[)][ ]ignoring[ ]max[ ]retries;[ ] [0-9]+ > [0-9]+$''',
            'listen':r'''^Server[ ]listening[ ]on[ ][0-9:.]+[ ]port[ ][0-9]+[.]$'''
        }
        compiled = { r:re.compile(patterns[r]) for r in iter(patterns) }
        matched = { r:re.match(compiled[r],message) for r in iter(patterns) }
        self.logger.debug("$$$ matched: {}".format(matched))
        lst = [v for k, v in matched.items() if v]
        self.logger.debug("lst: {}".format(lst))
        pattern = [k for k, v in matched.items() if v]
        self.logger.debug("pattern: {}".format(pattern))
        for p in pattern:
            match p:
                case 'listen'|'stopping'|'ignoring':
                    continue
                case 'pam_unix'|'failed'|'invalid'|'closed'|'reset'|'pam'|'pamano':
                    pattern0 = pattern[0]
                    self.logger.debug("::: pattern0: {}".format(pattern0))
                    val = lst[0] if lst else None
                    if val:
                        self.__add(hostname=val['hostname'], user=val['user'], pattern=pattern0)
                case _:
                    print('========  Unmatched =============')
                    break

logging.basicConfig(filename='/tmp/ssh_reporting.log',level=logging.DEBUG)
logger=logging.getLogger(__name__)
j = journal.Reader()
c = connection(logger)
j.seek_realtime(datetime.now() - timedelta(hours=24))
j.add_match('_SYSTEMD_UNIT=ssh.service')
for entry in j:
    logger.debug(entry['MESSAGE'])
    c.addmessage(entry['MESSAGE'])
logger.debug("--- Generating report")
c.report()