Module: Mu::Scenario::Pcap

Defined in:
lib/mu/scenario/pcap.rb,
lib/mu/scenario/pcap/rtp.rb,
lib/mu/scenario/pcap/fields.rb

Defined Under Namespace

Modules: Rtp Classes: Fields, PcapTooLarge

Constant Summary collapse

TSHARK_READ_TIMEOUT =

seconds

10.0
TSHARK_LINES_PER_PACKET = 
16384
TSHARK_OPTS = 
"-n -o tcp.desegment_tcp_streams:false"
TSHARK_OPTS_SUFFIX = 
TSHARK_OPTS
TSHARK_SIZE_OPTS = 
"-n -o 'column.format: cum_size, \"%B\"'"
TSHARK_PSML_OPTS = 
%Q{#{TSHARK_OPTS} -o 'column.format: "Protocol", "%p", "Info", "%i"'}
MAX_PCAP_SIZE =

100KB

102400
MAX_RAW_PCAP_SIZE_MB = 
25
MAX_RAW_PCAP_SIZE = 
MAX_RAW_PCAP_SIZE_MB * 1024 * 1000
EXCLUDE_FROM_SIZE_CHECK = 
['rtp'].freeze
PAR_VERSION = 
1

Class Method Summary collapse

Class Method Details

.export_to_par(pcap_path, opts = nil) ⇒ Object 



66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
 
# File 'lib/mu/scenario/pcap.rb', line 66

def self.export_to_par pcap_path, opts=nil
    opts ||= {}

    # Open pcap file
    File.exist?(pcap_path) or raise "Cannot open file '#{pcap_path}'."
    validate_pcap_size pcap_path
    pcap = open pcap_path, 'rb'

    # Get Mu::Pcap::Packets
    packets = to_pcap_packets pcap, opts[:isolate_l7]

    # Write normalized packets to tempfile
    tmpdir = Dir.mktmpdir
    norm_pcap = File.open "#{tmpdir}/normalized.pcap", 'wb'
    pcap = Mu::Pcap.from_packets packets
    pcap.write norm_pcap
    norm_pcap.close

    # Get wireshark dissected field values for all packets.
    `tshark -T fields #{TSHARK_OPTS} #{Fields::TSHARK_OPTS} -Eseparator='\xff' -r #{norm_pcap.path} > #{tmpdir}/fields`
    fields = open "#{tmpdir}/fields", 'rb'

    # Get wireshark dissected field values for all packets.
    fields_array = []
    if fields
        packets.each do |packet|
            fields_array <<  Fields.next_from_io(fields)
        end
    end

    # Protocol specific preprocessing, packets may be deleted.
    Rtp.preprocess packets, fields_array

    File.open "#{tmpdir}/packets.dump", 'wb' do |f|
        Marshal.dump packets, f
    end

    # Create a second pcap with packets removed.
    norm_pcap = File.open "#{tmpdir}/normalized.pcap", 'wb'
    pcap = Mu::Pcap.from_packets packets
    pcap.write norm_pcap
    norm_pcap.close

    # Dump PSML to file.
    # (The no-op filter sometimes produces slighty more verbose descriptions.)
    `tshark -T psml #{TSHARK_PSML_OPTS} -r #{norm_pcap.path} -R 'rtp or not rtp' > #{tmpdir}/psml`

    # Dump PDML io file.
    `tshark -T pdml #{TSHARK_OPTS} -r #{norm_pcap.path} > #{tmpdir}/pdml`
    pdml = open "#{tmpdir}/pdml", 'rb'

    # Create about
    open "#{tmpdir}/about", 'w' do |about|
        about.puts({:par_version => PAR_VERSION}.to_json)
    end

    # Create zip
    Dir.chdir tmpdir do
        system "zip -q dissected.zip about pdml psml fields packets.dump normalized.pcap"
        return open("dissected.zip")
    end
ensure
    if tmpdir
        FileUtils.rm_rf tmpdir
    end
end

.reset_options(options) ⇒ Object 



29
30
31
32
33
34
 
# File 'lib/mu/scenario/pcap.rb', line 29

def self.reset_options options
    return unless options
    tshark_opts = options << ' ' << TSHARK_OPTS_SUFFIX
    remove_const(:TSHARK_OPTS) if const_defined?(:TSHARK_OPTS)
    const_set(:TSHARK_OPTS, tshark_opts)
end

.to_pcap_packets(io, isolate_l7 = true) ⇒ Object 



133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
 
# File 'lib/mu/scenario/pcap.rb', line 133

def self.to_pcap_packets io, isolate_l7=true
    packets = []

    # Read Pcap packets from Pcap
    Mu::Pcap.each_pkthdr io do |pkthdr|
        if pkthdr.len != pkthdr.caplen
            raise Mu::Pcap::ParseError, "Error: Capture contains truncated packets. " +
                "Try recapturing with an increased snapshot length."
        end
        if not pkthdr.pkt.is_a? Mu::Pcap::Ethernet
            warning 'Unable to parse packet, skipping.'
        end
        packets << pkthdr.pkt
    end

    if (packets.length == 0)
        raise Mu::Pcap::ParseError, "No valid packets found!"
    end

    packets = Mu::Pcap::IPv4.reassemble packets

    if isolate_l7
        packets = Mu::Pcap::Packet.isolate_l7 packets
    end

    packets = Mu::Pcap::Packet.normalize packets
    packets = Mu::Pcap::TCP.split packets

    packets
end

.validate_pcap_size(path) ⇒ Object 



36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
 
# File 'lib/mu/scenario/pcap.rb', line 36

def self.validate_pcap_size(path)
    tshark_filter = EXCLUDE_FROM_SIZE_CHECK.map{ |proto| "not #{proto}" }.join " and "
    io = ::IO.popen "tshark #{TSHARK_SIZE_OPTS} -r #{path} -R '#{tshark_filter}' | tail -1"
    if ::IO.select [ io ], nil, nil, TSHARK_READ_TIMEOUT
        if io.eof?
            size = 0
        else
            last_line = io.readline
            size = last_line.to_i
        end
    end

    if size.nil? or size == 0
        size = File.size(path)
    end

    if size > MAX_PCAP_SIZE
        raise PcapTooLarge, "Selected packets have a size of #{size} bytes which " +
            "exceeds the #{MAX_PCAP_SIZE} byte maximum."
    end

    if size > MAX_RAW_PCAP_SIZE
        raise PcapTooLarge, "Selected packets have a raw size of #{size} bytes which " +
            "exceeds the #{MAX_RAW_PCAP_SIZE_MB}MB maximum."
    end

    return size
end

.warning(msg) ⇒ Object 



164
165
166
 
# File 'lib/mu/scenario/pcap.rb', line 164

def self.warning msg
    $stderr.puts "WARNING: #{msg}"#, caller, $!
end