diff options
Diffstat (limited to 'nselib/multicast.lua')
| -rw-r--r-- | nselib/multicast.lua | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/nselib/multicast.lua b/nselib/multicast.lua new file mode 100644 index 0000000..ccdb72a --- /dev/null +++ b/nselib/multicast.lua @@ -0,0 +1,179 @@ +--- +-- Utility functions for sending MLD requests and parsing reports. +-- +-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html + +local nmap = require "nmap" +local ipOps = require "ipOps" +local packet = require "packet" +local stdnse = require "stdnse" +local string = require "string" +local table = require "table" + +_ENV = stdnse.module("multicast", stdnse.seeall) + +--- +-- Performs an MLD general query on the selected interface and caches the results such that +-- subsequent calls to this function do not generate additional traffic. +-- +-- @param if_nfo A table containing information about the interface to send the request on. +-- Can be one of those returned by nmap.list_interfaces(). +-- @param arg_timeout The amount of time to wait for reports. +-- +-- @return A list of tables, each table containing three items, namely device, layer 2 reply and layer 3 reply. +-- +mld_query = function( if_nfo, arg_timeout ) + -- check if the interface name is valid or if nmap can find one + if if_nfo == nil then + return nil + end + + -- we need some ID for this interface & address combination to use as the + -- registry key and the object to lock the mutex on + local reg_entry = "mld_reports_" .. if_nfo.device .. "_" .. if_nfo.address + local mutex = nmap.mutex( reg_entry ) + mutex('lock') + + -- first check if nmap.registry contains reports for this interface from a previous call of this function + if nmap.registry[reg_entry] ~= nil then + mutex('done') + return nmap.registry[reg_entry] + end + + if not ipOps.ip_in_range(if_nfo.address, "fe80::/10") -- link local address + or if_nfo.link ~= "ethernet" then -- not the loopback interface + mutex('done') + return nil + end + + -- create the query packet + local src_mac = if_nfo.mac + local src_ip6 = ipOps.ip_to_str(if_nfo.address) + local dst_mac = packet.mactobin("33:33:00:00:00:01") + local dst_ip6 = ipOps.ip_to_str("ff02::1") + local general_qry = ipOps.ip_to_str("::") + + local dnet = nmap.new_dnet() + local pcap = nmap.new_socket() + + dnet:ethernet_open(if_nfo.device) + pcap:pcap_open(if_nfo.device, 1500, false, "ip6[40:1] == 58") + + local probe = packet.Frame:new() + probe.mac_src = src_mac + probe.mac_dst = dst_mac + probe.ip_bin_src = src_ip6 + probe.ip_bin_dst = dst_ip6 + + probe.ip6_tc = 0 + probe.ip6_fl = 0 + probe.ip6_hlimit = 1 + + probe.icmpv6_type = packet.MLD_LISTENER_QUERY + probe.icmpv6_code = 0 + + -- Add a non-empty payload too. + probe.icmpv6_payload = ( + "\x00\x01" .. -- maximum response delay 1 millisecond (if 0, virtualbox TCP/IP stack crashes) + "\x00\x00" .. -- reserved + ipOps.ip_to_str("::") -- empty address - general MLD query + ) + probe:build_icmpv6_header() + probe.exheader = string.pack(">BBBB I2 BB", + packet.IPPROTO_ICMPV6, -- next header + 0x00, -- length not including first 8 octets + 0x05, -- type is router alert + 0x02, -- length 2 bytes + 0x00, -- router alert MLD + 0x01, -- padding type PadN + 0x00 -- padding length 0 + ) + probe.ip6_nhdr = packet.IPPROTO_HOPOPTS + probe:build_ipv6_packet() + probe:build_ether_frame() + + -- send the query packet + dnet:ethernet_send(probe.frame_buf) + + -- wait for responses to the query packet + pcap:set_timeout(1000) + local pcap_timeout_count = 0 + local nse_timeout = arg_timeout or 10 + local start_time = nmap:clock() + local addrs = {} + nmap.registry[reg_entry] = {} + + repeat + local status, length, layer2, layer3 = pcap:pcap_receive() + local cur_time = nmap:clock() + if status then + local l2reply = packet.Frame:new(layer2) + local l3reply = packet.Packet:new(layer3, length, true) + local target_ip = l3reply.ip_src + if l3reply.ip6_nhdr == packet.MLD_LISTENER_REPORT or l3reply.ip6_nhdr == packet.MLDV2_LISTENER_REPORT then + table.insert( + nmap.registry[reg_entry], + { if_nfo.device, l2reply, l3reply } + ) + end + end + until ( cur_time - start_time >= nse_timeout ) + + -- clean up + dnet:ethernet_close() + pcap:pcap_close() + + mutex('done') + return nmap.registry[reg_entry] +end + +--- +-- Extracts IP addresses from MLD reports captured by the mld_query function. +-- +-- @param reports The output of the mld_query function. +-- +-- @return A list of tables, each table containing three items, namely device, mac and a list of addresses. +-- +mld_report_addresses = function(reports) + local rep_addresses = {} + for _, report in pairs(reports) do + local device = report[1] + local l2reply = report[2] + local l3reply = report[3] + + local target_ip = l3reply.ip_src + if l3reply.ip6_nhdr == packet.MLD_LISTENER_REPORT or l3reply.ip6_nhdr == packet.MLDV2_LISTENER_REPORT then + + -- if this is the first reply from the target, make an entry for it + if not rep_addresses[target_ip] then + rep_addresses[target_ip] = stdnse.output_table() + end + local rep = rep_addresses[target_ip] + rep.device = device + rep.mac = stdnse.format_mac(l2reply.mac_src) + rep.multicast_ips = rep.multicast_ips or {} + + -- depending on the MLD version of the report, add appropriate IP addresses + if l3reply.ip6_nhdr == packet.MLD_LISTENER_REPORT then + local multicast_ip = ipOps.str_to_ip( l3reply:raw(0x38, 16) ) -- IP starts at byte 0x38 and is 16 bytes long + table.insert(rep.multicast_ips, multicast_ip) + elseif l3reply.ip6_nhdr == packet.MLDV2_LISTENER_REPORT then + local no_records = l3reply:u16(0x36) + local record_offset = 0 + local records_start = 0x38 + for i = 1, no_records do + -- for the format description, see RFC3810 (ch. 5.2) + local aux_data_len = l3reply:u8(records_start + record_offset + 1) + local no_sources = l3reply:u16(records_start + record_offset + 2) + local multicast_ip = ipOps.str_to_ip(l3reply:raw(records_start + record_offset + 4, 16)) + table.insert(rep.multicast_ips, multicast_ip) + record_offset = record_offset + 4 + 16 + no_sources * 16 + aux_data_len * 4 + end + end + + end + end + return rep_addresses +end + +return _ENV |