Python: module dhcp

dhcp | index /build/dshell/src/dshell/decoders/dhcp/dhcp.py

Modules
`` |  |
binascii | dpkt | dshell | util

Classes
`` |  | dshell.UDPDecoder(dshell.IPDecoder) DshellDecoder
class DshellDecoder(dshell.UDPDecoder)
`` |  | Method resolution order: DshellDecoder dshell.UDPDecoder dshell.IPDecoder dshell.Decoder __builtin__.object Methods defined here: __init__(self) packetHandler(self, udp, data) `# A packetHandler is used to ensure that every DHCP packet in the traffic is parsed` Methods inherited from dshell.UDPDecoder: IPHandler(self, addr, pkt, ts, **kwargs) `IPv4 dispatch, hands address, UDP payload and packet up to UDP callback` UDP(self, addr, data, pkt, ts=None, **kwargs) `will call self.packetHandler(udp=Packet(),data=data) (see Packet() for Packet object common attributes) udp.pkt will contain the raw IP data data will contain the decoded UDP payload State tracking: only if connectionHandler or blobHandler is present and packetHandler is not present UDPDecoder will call: self.connectionInitHandler(conn=Connection()) when UDP state is established (see Connection() for Connection object attributes) self.blobHandler(conn=Connection(),blob=Blob()) when stream direction switches (if following stream) blob=(see Blob() objects) self.connectionHandler(conn=Connection()) when UDP state is flushed (if following stream) state is flushed when stale or when maxblobs is exceeded if maxblobs exceeded, current data will go into new connection self.connectionCloseHandler(conn=Connection()) when state is discarded (always)` Methods inherited from dshell.IPDecoder: ipdefrag(self, pkt) `ip fragment reassembly` rawHandler(self, pktlen, pkt, ts, **kwargs) `takes ethernet data and determines if it contains IP or IP6. defragments IPv4 if 6to4, unencaps the IPv6 If IP/IP6, hands off to IPDecoder via IPHandler()` Data and other attributes inherited from dshell.IPDecoder: IP_PROTO_MAP = {0: 'IP', 1: 'ICMP', 6: 'TCP', 17: 'UDP', 41: 'IP6', 58: 'ICMP6'} Methods inherited from dshell.Decoder: __repr__(self) __super__(self) `convenience function to get bound instance of superclass` alert(self, *args, **kw) `sends alert to output handler typically self.alert will be called with the decoded data and the packet/connection info dict last, as follows: self.alert(alert_arg,alert_arg2...,alert_data=value,alert_data2=value2....,**conn/pkt.info()) example: self.alert(decoded_data,conn.info(),blob.info()) [blob info overrides conn info] this will pass all information about the decoder, the connection, and the specific event up to the output module if a positional arg is a dict, it updates the kwargs if an arg is a list, it extends the arg list else it is appended to the arg list all arguments are optional, at the very least you want to pass the **pkt/conn.info() so all traffic info is available. output modules handle this data as follows: - the name of the alerting decoder is available in the "decoder" field - all non-keyword arguments will be concatenated into the "data" field - keyword arguments, including all provided by .info() will be used to populate matching fields - remaining keyword arguments that do not match fields will be represented by "key=value" strings concatenated together into the "extra" field` cleanConnectionStore(self) `cleans connection store of all information, flushing out data` cleanup(self, ts) `if cleanup interval expired, close connections not updated in last interval` close(self, conn, ts=None) `for connection based decoders close and discard the connection object` debug(self, msg) `logs msg at debug level` decode(self, *args, **kw) `# we get the raw output from pcapy as header, data` dump(self, *args, **kw) `write packet data (probably to the PCAP writer if present)` error(self, msg) `logs msg at error level` find(self, addr, state=None) getASN(self, ip, db=None, notfound='--') `Get ASN associated with an IP. Requires GeoIP library (geoip2) and data files.` getGeoIP(self, ip, db=None, notfound='--') `Get country code associated with an IP. Requires GeoIP library (geoip2) and data files.` log(self, msg, level=20) `logs msg at specified level (default of INFO is for -v/--verbose output)` parseArgs(self, args, options={}) `called to parse command-line arguments and cli/config file options if options dict contains 'all' or the decoder name as a key class members will be updated from value` parseOptions(self, options={}) `option keys:values will set class members (self.key=value) if key is in optiondict` postFile(self) postModule(self) `postModule is called after capture stops default postModule, prints basic decoding stats` preFile(self) preModule(self) `preModule is called before capture starts default preModule, dumps object data to debug` stop(self, conn) `stop following connection handlers will not be called, except for connectionCloseHandler` track(self, addr, data=None, ts=None, offset=None, **kwargs) `connection tracking for TCP and UDP finds or creates connection based on addr updates connection with data if provided (using offset to reorder) tracks timestamps if ts provided extra args get passed to new connection objects` warn(self, msg) `logs msg at warning level` write(self, obj, **kw) `write session data` Data descriptors inherited from dshell.Decoder: __dict__ `dictionary for instance variables (if defined)` __weakref__ `list of weak references to the object (if defined)`

Functions
`` |  | unpack(...) `Unpack the string containing packed C structure data, according to fmt. Requires len(string) == calcsize(fmt).`

Data
`` |  | dObj = dhcp (udp and port 67)