Add update_mikrotik_dns.py

update_mikrotik_dns.py

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+#! /usr/bin/python
+#
+# update_dns.py - Update DNS static entries on your Mikrotik Router(s) using this python script.
+# Copyright (C) 2021 WILDERNETS LLC, Distributed under GPL-3.0, GNU General Public License v3.0 only
+#
+# How it works:
+# - Grab a copy of the master host table off the host table server.
+# - Get existing DNS static entries from a list of Mikrotik routers.
+# - Compare entries to the master host table
+# - Issue add/set/remove commands as needed to update the Mikrotik DNS entries.
+#
+# Setup Notes:
+# - Setup DNS server on your mikrotik router(s)
+# - Run this on a trusted secure system so you don't have to trust the host master with access to your router(s).
+# - OR just Comment out Step0 and run from the machine that has the host master file.
+# - Setup password-less ssh to the host master machine.
+# - Setup password-less ssh to your router(s).
+# - Adv Topic: consider setting up a portable subnet/IP for your router so you can implement DNS server redundancy.
+# (I use 10.10.10.10 on two routers and 10.10.10.1 on two routers and inject these as /32 into OSPF)
+#
+# Requirements:
+# - Setup password-less SSH using keys to the machine that hosts the master copy of the host table
+# - Setup password-less SSH using keys to the router that act as DNS servers
+# - Change the Script vars listed below
+# - Test on a non-production router
+#
+# Coding Notes:
+# - Hosts file parsed into two master dictionaries.
+# - For each router updated a working copy is made of these two masters.
+# - As hosts are processed they are deleted from the dictionary copy.
+# - Next router updated gets a brand new copy from the master.
+#
+import re               # strip comments
+import sys              # system stuff
+import subprocess       # Popen command
+import os               # Execute scp command
+
+# Script vars
+#HOSTMASTER = "nismaster:etc/hosts"
+#HOSTMASTER = "/etc/hosts"
+HOSTSFILE  = "/root/hosts.txt"
+SSHCMD     = "/ip dns static export"
+routerlist = ['10.87.2.1']
+routeruser = "dnsupdate"
+debug      = 1
+
+# Step0 Go Grab latest hosts file
+#print "# Getting hosts file: scp "+HOSTMASTER+" "+HOSTSFILE
+#os.system("scp "+HOSTMASTER+" "+HOSTSFILE)
+
+#os.system("cp "+HOSTMASTER+" "+HOSTSFILE)
+
+# Step1 Open hosts file, parse and check for duplicates
+if debug: print("# Verifying hostsfile: "+HOSTSFILE)
+error = 0
+masteriphosts = {}
+masterhostip  = {}
+hosts = open(HOSTSFILE,'r',encoding='utf-8')
+
+for line in hosts:
+    if not line.startswith('#') and line.strip():
+        line=re.sub(r'#.*$', '', line).rstrip()
+        data = line.split()
+        i = data.pop(0)
+        if debug > 1: print("checking ip "+i)
+        if (i in masteriphosts):
+            print("ERROR: Duplicate ipaddress "+i+" for "+str(data)+" and "+str(masteriphosts[i]))
+            error += 1
+        else:
+            masteriphosts[i] = data
+
+        for h in data:
+            if debug > 1: print("checking host "+h)
+            if (h in masterhostip):
+                print("ERROR: Duplicate hostname "+h+" in hosts file for "+i+" and "+masterhostip[h])
+                error += 1
+            else:
+                masterhostip[h] = i
+if error:
+    exit(1)
+
+for router in routerlist:
+    USERHOST = routeruser+"@"+router
+    iphosts  = masteriphosts.copy()
+    hostip   = masterhostip.copy()
+    addrname = {}
+    nameaddr = {}
+
+    # Step2 SSH to EACH DNS Router and Export the DNS static table and Parse
+    print("# Getting router DNS entries: ssh",USERHOST, SSHCMD)
+    ssh = subprocess.Popen(["ssh", "%s" % USERHOST, SSHCMD],
+                           shell=False,
+                           stdout=subprocess.PIPE,
+                           stderr=subprocess.PIPE)
+    result = ssh.stdout.readlines()
+    if result == []:
+        error = ssh.stderr.readlines()
+       # print >>sys.stderr, "ERROR: %s" % error
+    else:
+        if debug: print("# Parsing DNS Static Export")
+        for line in result:
+            if line.startswith(b'\n') :
+                line=re.sub(r'add address=', '', line).rstrip()
+                line=re.sub(r'name=', '', line)
+                a,n = line.split()
+                # Check name is a Host
+                if (n in hostip):
+                    i = hostip[n]
+                    # Check for duplicate DNS names
+                    if (n in nameaddr):
+                        command = "ssh "+USERHOST+" /ip dns static remove [find name="+n+" address="+a+"]; # Delete Duplicate"
+                        print(command)
+                        os.system(command)
+                    # Changed address for name
+                    elif (a != i):
+                        command = "ssh "+USERHOST+" /ip dns static set address="+i+" [find name="+n+" address="+a+"]; # Changed Address"
+                        print(command)
+                        os.system(command)
+                    addrname[i] = n
+                    nameaddr[n] = i
+                    # Delete key from hostip after used so they are gone before step3
+                    del hostip[n]
+                else:
+                    # Delete it if not Host
+                    command = "ssh "+USERHOST+" /ip dns static remove [find name="+n+" address="+a+"]; # Delete Entry"
+                    print(command)
+                    os.system(command)
+
+    # Step3 Remaining keys in hostip need to be added.
+    if debug: print("# Generate Add Commands")
+    for h in hostip:
+        i = hostip[h]
+        command = "ssh "+USERHOST+" /ip dns static add address="+i+" name="+h+"; # Add Entry"
+        print(command)
+        os.system(command)
+
+if debug: print("# Finished")
+exit(0)