# encoding: UTF-8

require 'rex/proto/sip/response'

module Msf
  # SIP protocol support
  module Exploit::Remote::SIP
    # Parses +response+, extracts useful metdata and then reports on it
    def parse_response(response, proto, desired_headers = %w(User-Agent Server))
      endpoint = "#{rhost}:#{rport}/#{proto}"
      begin
        options_response = Rex::Proto::SIP::Response.parse(response)
      rescue ArgumentError => e
        vprint_error("#{endpoint} is not SIP: #{e}")
        return
      end

      # We know it is SIP, so report
      report_service(
        host: rhost,
        port: rport,
        proto: proto,
        name: 'sip'
      )

      # Do header extraction as necessary
      extracted_headers = {}
      unless desired_headers.nil? || desired_headers.empty?
        desired_headers.each do |desired_header|
          next unless (found_header = options_response.header(desired_header))
          extracted_headers[desired_header] ||= []
          extracted_headers[desired_header] |= found_header
        end

        # report on any extracted headers
        extracted_headers.each do |k, v|
          report_note(
            host: rhost,
            port: rport,
            proto: proto,
            type: "sip_#{k}",
            data: v
          )
        end
      end

      status = "#{endpoint} #{options_response.status_line}"
      status += ": #{extracted_headers}" unless extracted_headers.empty?
      print_status(status)
    end

    def create_probe(ip, proto)
      suser = Rex::Text.rand_text_alphanumeric(rand(8) + 1)
      shost = Rex::Socket.source_address(ip)
      src   = "#{shost}:#{datastore['RPORT']}"

      data  = "OPTIONS sip:#{datastore['TO']}@#{ip} SIP/2.0\r\n"
      data << "Via: SIP/2.0/#{proto} #{src};branch=z9hG4bK.#{format('%.8x', rand(0x100000000))};rport;alias\r\n"
      data << "From: sip:#{suser}@#{src};tag=70c00e8c\r\n"
      data << "To: sip:#{datastore['TO']}@#{ip}\r\n"
      data << "Call-ID: #{rand(0x100000000)}@#{shost}\r\n"
      data << "CSeq: 1 OPTIONS\r\n"
      data << "Contact:  sip:#{suser}@#{src}\r\n"
      data << "Max-Forwards: 20\r\n"
      data << "User-Agent: #{suser}\r\n"
      data << "Accept: text/plain\r\n"
      data << "Content-Length: 0\r\n"
      data << "\r\n"
      data
    end
  end
end