From 36e63f549b912ef498a17456a1eee9b6f83d0310 Mon Sep 17 00:00:00 2001
From: David Mougeolle <moodule@protonmail.com>
Date: Sat, 14 Mar 2020 19:15:32 +0100
Subject: [PATCH] Rewrite DnsReverse in functional style

---
 theHarvester/__main__.py            |  28 +++----
 theHarvester/discovery/dnssearch.py | 124 ++++++++++++----------------
 2 files changed, 64 insertions(+), 88 deletions(-)

diff --git a/theHarvester/__main__.py b/theHarvester/__main__.py
index 4c4adf65..134be97f 100644
--- a/theHarvester/__main__.py
+++ b/theHarvester/__main__.py
@@ -473,26 +473,22 @@ async def handler(lst):
     dnsrev = []
     if dnslookup is True:
         print('\n[*] Starting active queries.')
-        analyzed_ranges = []
+        from theHarvester.discovery.dnssearch import reverse_ip_range
+        reversed_ranges = []
         for entry in host_ip:
-            print(entry)
             ip = entry.split(':')[0]
             ip_range = ip.split('.')
             ip_range[3] = '0/24'
-            s = '.'
-            ip_range = s.join(ip_range)
-            if not analyzed_ranges.count(ip_range):
-                print('[*] Performing reverse lookup in ' + ip_range)
-                a = dnssearch.DnsReverse(ip_range, True)
-                res = a.process()
-                analyzed_ranges.append(ip_range)
-            else:
-                continue
-            for cname in res:
-                if word in cname:
-                    dnsrev.append(cname)
-                    if cname not in full:
-                        full.append(cname)
+            ip_range = '.'.join(ip_range)
+            if not reversed_ranges.count(ip_range):
+                print('\n[*] Performing reverse lookup on ' + ip_range)
+                res = reverse_ip_range(iprange=ip_range,verbose=True)
+                for cname in res:
+                    if word in cname:
+                        dnsrev.append(cname)
+                        if cname not in full:
+                            full.append(cname)
+                reversed_ranges.append(ip_range)
         print('[*] Hosts found after reverse lookup (in target domain):')
         print('--------------------------------------------------------')
         for xh in dnsrev:
diff --git a/theHarvester/discovery/dnssearch.py b/theHarvester/discovery/dnssearch.py
index 0b7ba88f..6b0728c0 100644
--- a/theHarvester/discovery/dnssearch.py
+++ b/theHarvester/discovery/dnssearch.py
@@ -68,80 +68,60 @@ def list_ips_in_network_range(
     __network = IPv4Network(iprange, strict=False)
     return [__address.exploded for __address in __network.hosts()]
 
-class DnsReverse:
+def reverse_single_ip(
+        ip: str,
+        verbose: bool = False) -> str:
     """
-    Find all the IPs in a range associated with a CNAME.
+    Reverse a single IP and output the linked CNAME, if it exists.
+
+    Parameters
+    ----------
+    ip: str.
+        The IP to reverse.
+    verbose: bool.
+        Print the progress or not.
+
+    Returns
+    -------
+    out: str.
+        The corresponding CNAME or None.
     """
+    if verbose:
+        sys.stdout.write(chr(27) + '[2K' + chr(27) + '[G')
+        sys.stdout.write('\r' + ip + ' - ')
+        sys.stdout.flush()
+    try:
+        dns_record_from_ip_answer = dns.reversename.from_address(ip)
+        ptr_record_answer = dns.resolver.query(dns_record_from_ip_answer, 'PTR')
+        a_record_answer = dns.resolver.query(ptr_record_answer[0].to_text(), 'A')
+        print(a_record_answer.canonical_name)
+        return str(a_record_answer.canonical_name)
+    except Exception:
+        return ''
 
-    def __init__(
-            self,
-            iprange: str,
-            verbose: bool = False) -> None:
-        """
-        Initialize.
+def reverse_ip_range(
+        iprange: str,
+        verbose: bool = False) -> List[str]:
+    """
+    Reverse all the IPs stored in a network range.
 
-        Parameters
-        ----------
-        iprange: str.
-            An IPv4 range formated as 'x.x.x.x/y'.
-            The last digit can be set to anything, it will be ignored.
-        verbose: bool.
-            Print the progress or not.
+    Parameters
+    ----------
+    iprange: str.
+        An IPv4 range formated as 'x.x.x.x/y'.
+        The last digit can be set to anything, it will be ignored.
+    verbose: bool.
+        Print the progress or not.
 
-        Returns
-        -------
-        out: None.
-        """
-        self.iprange = iprange
-        self.verbose = verbose
-
-    def run(
-            self,
-            ip: str) -> str:
-        """
-        Reverse a single IP and output the linked CNAME, if it exists.
-
-        Parameters
-        ----------
-        ip: str.
-            The IP to reverse.
-
-        Returns
-        -------
-        out: str.
-            The corresponding CNAME or None.
-        """
-        if self.verbose:
-            esc = chr(27)
-            sys.stdout.write(esc + '[2K' + esc + '[G')
-            sys.stdout.write('\r' + ip + ' - ')
-            sys.stdout.flush()
-        try:
-            dns_record_from_ip_answer = dns.reversename.from_address(ip)
-            ptr_record_answer = dns.resolver.query(dns_record_from_ip_answer, 'PTR')
-            a_record_answer = dns.resolver.query(ptr_record_answer[0].to_text(), 'A')
-            print(a_record_answer.canonical_name)
-            return str(a_record_answer.canonical_name)
-        except Exception:
-            return ''
-
-    def process(
-            self) -> List[str]:
-        """
-        Reverse all the IPs stored in 'self.list'.
-
-        Parameters
-        ----------
-
-        Returns
-        -------
-        out: list.
-            The list of all the found CNAME records.
-        """
-        results = []
-        for entry in list_ips_in_network_range(self.iprange):
-            host = self.run(entry)
-            if host is not None and host:
-                # print(' : ' + host.split(':')[1])
-                results.append(host)
-        return results
+    Returns
+    -------
+    out: list.
+        The list of all the found CNAME records.
+    """
+    results = []
+    for ip in list_ips_in_network_range(iprange):
+        host = reverse_single_ip(ip=ip, verbose=verbose)
+        if host is not None and host:
+            # print(' : ' + host.split(':')[1])
+            results.append(host)
+    return results