mirror of
https://github.com/nmap/nmap.git
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Add jah's enhanced ASN.nse that consolidates answers and gives up if the DNS
server is uncooperative.
This commit is contained in:
david
@@ -1,5 +1,9 @@
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# Nmap Changelog ($Id$); -*-text-*-
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o Enhanced the AS Numbers script (ASN.nse) to better consolidate
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results and bail out if the DNS server doesn't support the ASN
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queries. [Jah]
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o Made DNS timeouts in NSE dependent on the timing template [Jah]
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o Added two new nselib modules, netbios and smb, that contain common
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343
scripts/ASN.nse
343
scripts/ASN.nse
@@ -5,7 +5,7 @@ sends DNS TXT queries to a DNS server which in turn queries a third party
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service provided by Team Cymru (team-cymru.org) using an in-addr.arpa style
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zone set-up especially for use by Nmap.
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\n
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The respnses to these queries contain both Origin and Peer ASNs and their
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The responses to these queries contain both Origin and Peer ASNs and their
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descriptions, displayed along with the BG Prefix and Country Code.
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\n
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The script caches results to reduce the number of queries and should perform a
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@@ -44,9 +44,10 @@ runlevel = 1
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local dns = require "dns"
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local comm = require "comm"
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local ipOps = require "ipOps"
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local dns = require "dns"
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local comm = require "comm"
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local ipOps = require "ipOps"
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local stdnse = require "stdnse"
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local mutex = nmap.mutex( id )
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@@ -72,21 +73,31 @@ end
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-- relevent information from the response. Mutual exclusion is used so that results can be
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-- cached and so a single thread will be active at any time.
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-- @param host Host Table.
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-- @return Formatted answers or nil on NXDOMAIN/errors.
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-- @return Formatted answers or nil on errors.
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action = function( host )
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mutex "lock"
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-- check for cached data
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local in_cache, records
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local combined_records = {}
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local output, records, combined_records = {}, {}, {}
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in_cache, records = check_cache( host.ip )
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records = records or {}
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-- check for cached data
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local in_cache, cache_data = check_cache( host.ip )
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if in_cache and type( cache_data ) == "table" then
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combined_records = cache_data
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elseif in_cache and type( cache_data ) == "string" and cache_data ~= "Unknown Error" then
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output = cache_data
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end
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if not in_cache then
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local dname = dns.reverse( host.ip )
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local zone_repl, IPv = "%.in%-addr%.arpa", 4
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if host.ip:match( ":" ) then
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zone_repl, IPv = "%.ip6%.arpa", 6
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end
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---
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-- @class table
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-- @name cymru
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@@ -94,76 +105,51 @@ action = function( host )
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-- \n nmap.asn.cymru.com for IPv4 to Origin AS lookup.
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-- \n peer-nmap.asn.cymru.com for IPv4 to Peer AS lookup.
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-- \n nmap6.asn.cymru.com for IPv6 to Origin AS lookup.
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local cymru = { [4] = { ["Origin"] = ".nmap.asn.cymru.com", ["Peer"] = ".peer-nmap.asn.cymru.com" },
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[6] = { ["Origin"] = ".nmap6.asn.cymru.com" }
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local cymru = { [4] = { ".nmap.asn.cymru.com", ".peer-nmap.asn.cymru.com" },
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[6] = { ".nmap6.asn.cymru.com" }
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}
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local zone_repl, IPv = "%.in%-addr%.arpa", 4
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if host.ip:match( ":" ) then
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zone_repl, IPv = "%.ip6%.arpa", 6
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end
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-- name to query for
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local dname = dns.reverse( host.ip )
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-- perform queries for each applicable zone
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for asn_type, zone in pairs( cymru[IPv] ) do
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for _, zone in ipairs( cymru[IPv] ) do
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local asn_type = ( zone:match( "peer" ) and "Peer" ) or "Origin"
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-- replace arpa with cymru zone
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local temp = dname
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dname = dname:gsub( zone_repl, zone )
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-- send query and recognise and organise fields from response
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local success, retval = result_recog( ip_to_asn( dname ), asn_type, records )
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-- if success then records = retval end
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-- send query
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local success, response = ip_to_asn( dname )
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if not success then
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records = {}
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output = ( type( response ) == "string" and response ) or output
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break
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end
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-- recognise and organise fields from response
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local success = result_recog( response, asn_type, records, host.ip )
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-- un-replace arpa zone
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dname = temp
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end
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-- combine records into unique BGP
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for _, record in ipairs( records ) do
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if not combined_records[record.cache_bgp] then
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combined_records[record.cache_bgp] = record
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elseif combined_records[record.cache_bgp].asn_type ~= record.asn_type then
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-- origin before peer.
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if record.asn_type == "Origin" then
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combined_records[record.cache_bgp].asn = { unpack( record.asn ), unpack( combined_records[record.cache_bgp].asn ) }
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else
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combined_records[record.cache_bgp].asn = { unpack( combined_records[record.cache_bgp].asn ), unpack( record.asn ) }
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end
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end
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end
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-- combine records into unique BGP, cache and format for output
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combined_records = process_answers( records, output, host.ip )
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-- cache combined records
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for _, rec in pairs( combined_records ) do
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table.insert( nmap.registry.asn.cache, rec )
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end
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end -- if not in_cache
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else -- records were in the cache
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combined_records = records
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end
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-- format each combined_record for output
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local output = {}
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for _, rec in pairs( combined_records ) do
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local r = {}
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if rec.bgp then r[#r+1] = rec.bgp end
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if rec.co then r[#r+1] = rec.co end
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output[#output+1] = ( "%s\n %s" ):format( table.concat( r, " | " ), table.concat( rec.asn, "\n " ) )
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end
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mutex "done"
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if type( output ) ~= "table" or #output == 0 then return nil end
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-- sort BGP asc.
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table.sort( output, function(a,b) return (get_prefix_length(a) or 0) > (get_prefix_length(b) or 0) end )
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return nice_output( output, combined_records )
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-- return combined and formatted answers
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return (" \n%s"):format( table.concat( output, "\n" ) )
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end -- action
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end
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---
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-- Checks whether the target IP address is within any BGP prefixes for which a query has
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-- already been performed and returns any applicable answers.
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-- already been performed and returns a pointer to the HOST SCRIPT RESULT displaying the applicable answers.
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-- @param ip String representing the target IP address.
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-- @return Boolean True if there are cached answers for the supplied target, otherwise
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-- false.
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@@ -171,34 +157,106 @@ end
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function check_cache( ip )
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local ret = {}
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-- collect any applicable answers
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for _, cache_entry in ipairs( nmap.registry.asn.cache ) do
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if ipOps.ip_in_range( ip, cache_entry.cache_bgp ) then
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ret[#ret+1] = cache_entry
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end
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end
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if #ret > 0 then return true, ret end
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if #ret < 1 then return false, nil end
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-- /0 signals that we want to kill this thread (all threads in fact)
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if #ret == 1 and type( ret[1].cache_bgp ) == "string" and ret[1].cache_bgp:match( "/0" ) then return true, nil end
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-- should return pointer unless there are more than one unique pointer
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local dirty, last_ip = false
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for _, entry in ipairs( ret ) do
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if last_ip and last_ip ~= entry.pointer then
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dirty = true; break
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end
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last_ip = entry.pointer
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end
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if not dirty then
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return true, ( "See the result for %s" ):format( last_ip )
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else
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return true, ret
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end
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return false, nil
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end
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---
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-- Extracts fields from the supplied DNS answer sections.
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-- Performs an IP address to ASN lookup. See http://www.team-cymru.org/Services/ip-to-asn.html#dns
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-- @param query String - PTR like DNS query.
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-- @return Boolean true for a successful dns query resulting in an answer, otherwise false.
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-- @return Table of answers or a String err msg.
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function ip_to_asn( query )
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if type( query ) ~= "string" or query == "" then
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return false, nil
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end
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-- error codes from dns.lua that we want to display.
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local err_code = {}
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err_code[3] = "No Such Name"
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-- dns query options
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local options = {}
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options.dtype = "TXT"
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options.retAll = true
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options.sendCount = 1
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if type( nmap.registry.args.dns ) == "string" and nmap.registry.args.dns ~= "" then
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options.host = nmap.registry.args.dns
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options.port = 53
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end
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-- send the query
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local decoded_response, other_response = dns.query( query, options)
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-- failed to find or get a response from any dns server - fatal
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if not decoded_response and ( other_response == nil or other_response == 9 ) then
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stdnse.print_debug( "%s Failed to send dns query. Response from dns.query(): %s", id, other_response or "nil" )
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return false, nil
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end
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-- error codes from dns.lua
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if not decoded_response and type( other_response ) == "number" then
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if other_response ~= 3 then stdnse.print_debug( "%s Error from dns.query() Code: %s in response to %s", id, other_response, query ) end
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return false, err_code[other_response] or "Unknown Error"
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end
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-- catch
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if not decoded_response then return false, nil end
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return true, decoded_response
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end
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---
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-- Extracts fields from the supplied DNS answer sections and generates a records entry for each.
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-- @param answers Table containing string DNS answers.
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-- @param asn_type String denoting whether the query is for Origin or Peer ASN.
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-- @param recs Table of existing recognised answers to which to add (ref to actions() records{}.
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-- @return Boolean true if successful otherwise false.
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function result_recog( answers, asn_type, recs )
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function result_recog( answers, asn_type, recs, discoverer_ip )
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if type( answers ) ~= "table" or #answers == 0 then return false end
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for _, answer in ipairs( answers ) do
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local t = {}
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t.pointer = discoverer_ip
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-- break the answer up into fields and strip whitespace
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local fields = { answer:match( ("([^|]*)|" ):rep(3) ) }
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for i, field in ipairs( fields ) do
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fields[i] = field:gsub( "^%s*(.-)%s*$", "%1" )
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end
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-- assign fields with labels to table
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t.cache_bgp = fields[2]
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t.asn_type = asn_type
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@@ -206,6 +264,7 @@ function result_recog( answers, asn_type, recs )
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t.bgp = "BGP: " .. fields[2]
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if fields[3] ~= "" then t.co = "Country: " .. fields[3] end
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recs[#recs+1] = t
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-- lookup AS descriptions for Origin AS numbers
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local asn_descr = nmap.registry.asn.descr
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local u = {}
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@@ -225,33 +284,6 @@ function result_recog( answers, asn_type, recs )
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end
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---
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-- Performs an IP address to ASN lookup. See http://www.team-cymru.org/Services/ip-to-asn.html#dns
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-- @param query String - PTR like DNS query.
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-- @return Table containing string answers or Boolean false.
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function ip_to_asn( query )
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if type( query ) ~= "string" or query == "" then
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return nil
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end
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-- dns query options
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local options = {}
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options.dtype = "TXT"
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options.retAll = true
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if type( nmap.registry.args.dns ) == "string" and nmap.registry.args.dns ~= "" then
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options.host = nmap.registry.args.dns
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options.port = 53
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end
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local decoded_response, other_response = dns.query( query, options)
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return decoded_response
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end
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---
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-- Performs an AS Number to AS Description lookup.
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-- @param asn String AS Number
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@@ -266,6 +298,7 @@ function asn_description( asn )
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-- dns query options
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local options = {}
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options.dtype = "TXT"
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options.sendCount = 1
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if type( nmap.registry.args.dns ) == "string" and nmap.registry.args.dns ~= "" then
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options.host = nmap.registry.args.dns
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options.port = 53
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@@ -283,6 +316,58 @@ function asn_description( asn )
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end
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---
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-- Processes records which are recognised dns answers by combining them into unique BGPs before caching
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-- them in the registry and returning combined_records. If there aren't any records (No Such Name message
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-- or dns failure) we signal this fact to other threads by using the cache and return with an empty table.
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-- @param records Table of recognised answers (may be empty).
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-- @param output String non-answer message or an empty table.
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-- @param ip String host.ip
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-- @return Table containing combined records for the target (or an empty table).
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function process_answers( records, output, ip )
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local combined_records = {}
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-- if records empty and no error message (output) then assume catastrophic dns failure and have all threads fail without trying.
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if #records == 0 and type( output ) ~= "string" then
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nmap.registry.asn.cache = { {["cache_bgp"] = "0/0"}, {["cache_bgp"] = "::/0"} }
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return {}
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end
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if #records == 0 and type( output ) == "string" then
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table.insert( nmap.registry.asn.cache, { ["pointer"] = ip, ["cache_bgp"] = get_assignment( ip, ( ip:match(":") and 48 ) or 29 ) } )
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return {}
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end
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if type( records ) ~= "table" or #records == 0 then
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return {}
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end
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-- combine fields for unique BGP
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for _, record in ipairs( records ) do
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if not combined_records[record.cache_bgp] then
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combined_records[record.cache_bgp] = record
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elseif combined_records[record.cache_bgp].asn_type ~= record.asn_type then
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-- origin before peer.
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if record.asn_type == "Origin" then
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combined_records[record.cache_bgp].asn = { unpack( record.asn ), unpack( combined_records[record.cache_bgp].asn ) }
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else
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combined_records[record.cache_bgp].asn = { unpack( combined_records[record.cache_bgp].asn ), unpack( record.asn ) }
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end
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end
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end
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-- cache combined records
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for _, rec in pairs( combined_records ) do
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table.insert( nmap.registry.asn.cache, rec )
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end
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return combined_records
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end
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---
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-- Calculates the prefix length for the given IP address range.
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@@ -313,3 +398,83 @@ function get_prefix_length( range )
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return ( string.len( first ) - hostbits )
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end
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---
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-- Given an IP address and a prefix length, returns a string representing a valid IP address assignment (size is not checked) which contains
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-- the supplied IP address. For example, with ip = 192.168.1.187 and prefix = 24 the return value will be 192.168.1.1-192.168.1.255
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-- @param ip String representing an IP address.
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-- @param prefix String or number representing a prefix length. Should be of the same address family as ip.
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-- @return String representing a range of addresses from the first to the last hosts (or nil in case of an error).
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-- @return Nil or error message in case of an error.
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function get_assignment( ip, prefix )
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local some_ip, err = ipOps.ip_to_bin( ip )
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if err then return nil, err end
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prefix = tonumber( prefix )
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if not prefix or ( prefix < 0 ) or ( prefix > string.len( some_ip ) ) then
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return nil, "Error in get_assignment: Invalid prefix length."
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end
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local hostbits = string.sub( some_ip, prefix + 1 )
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hostbits = string.gsub( hostbits, "1", "0" )
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local first = string.sub( some_ip, 1, prefix ) .. hostbits
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err = {}
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first, err[#err+1] = ipOps.bin_to_ip( first )
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last, err[#err+1] = ipOps.get_last_ip( ip, prefix )
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if #err > 0 then return nil, table.concat( err, " " ) end
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return first .. "-" .. last
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end
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---
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-- Decides what to output based on the content of the supplied paramaters and formats it for return by action().
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-- @param output String non-answer message to be returned as is or an empty table
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-- @param combined_records Table containing combined records.
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-- @return Formatted nice output string.
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||||
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function nice_output( output, combined_records )
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-- return a string message
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||||
if type( output ) == "string" and output ~= "" then
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return output
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||||
end
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||||
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||||
-- return nothing (dns failure)
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||||
if type( output ) ~= "table" then return nil end
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||||
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||||
-- format each combined_record for output
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||||
for _, rec in pairs( combined_records ) do
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||||
local r = {}
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||||
if rec.bgp then r[#r+1] = rec.bgp end
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||||
if rec.co then r[#r+1] = rec.co end
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if rec.asn then output[#output+1] = ( "%s\n %s" ):format( table.concat( r, " | " ), table.concat( rec.asn, "\n " ) ) end
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||||
end
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||||
|
||||
-- return nothing
|
||||
if #output == 0 then return nil end
|
||||
|
||||
-- sort BGP asc. and combine BGP when ASN info is duplicated
|
||||
table.sort( output, function(a,b) return (get_prefix_length(a) or 0) > (get_prefix_length(b) or 0) end )
|
||||
for i=1,#output,1 do
|
||||
for j=1,#output,1 do
|
||||
-- does everything after the first pipe match for i ~= j?
|
||||
if i ~= j and output[i]:match( "[^|]+|([^$]+$)" ) == output[j]:match( "[^|]+|([^$]+$)" ) then
|
||||
first = output[i]:match( "([%x%d:\.]+/%d+)%s|" ) -- the lastmost BGP before the pipe in i.
|
||||
second = output[j]:match( "([%x%d:\.]+/%d+)" ) -- first BGP in j
|
||||
-- add in the new BGP from j and delete j
|
||||
if first and second then
|
||||
output[i] = output[i]:gsub( first, ("%s and %s"):format( first, second ) )
|
||||
output[j] = ""
|
||||
end
|
||||
end
|
||||
end
|
||||
end
|
||||
|
||||
-- return combined and formatted answers
|
||||
return (" \n%s"):format( table.concat( output, "\n" ) )
|
||||
|
||||
end
|
||||
|
||||
Reference in New Issue
Block a user