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Add parsing libpcap and reading/writing PCAP file
Add parsing libpcap and reading/writing PCAP file for debugging.
Now you can easily dump the PCAP file in ryu controller.
Here is the quick example for dumping the data packets:
from ryu.lib import pcaplib
class SimpleSwitch13(app_manager.RyuApp):
OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
def __init__(self, *args, **kwargs):
super(SimpleSwitch13, self).__init__(*args, **kwargs)
self.mac_to_port = {}
# Creating an instance with a PCAP filename
self.pcap_pen = Writer(open('mypcap.pcap', 'wb'))
@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
def _packet_in_handler(self, ev):
msg = ev.msg
# Dump the data packet into PCAP file
self.pcap_pen.write_pkt(msg.data)
Signed-off-by: Che-Wei Lin <linton.tw@gmail.com>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
This commit is contained in:
Che-Wei Lin
FUJITA Tomonori
parent
a34eda1fe1
commit
3736b0c37d
288
ryu/lib/pcaplib.py
Normal file
288
ryu/lib/pcaplib.py
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@ -0,0 +1,288 @@
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"""
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Parsing libpcap and reading/writing PCAP file.
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Reference source: http://wiki.wireshark.org/Development/LibpcapFileFormat
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Libpcap File Format
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+---------------------+
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| |
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| Global Header |
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| |
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+---------------------+
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| Packet Header |
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+---------------------+
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| Packet Data |
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+---------------------+
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| Packet Header |
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+---------------------+
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| Packet Data |
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+---------------------+
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| ...
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+---------------- ...
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Sample usage of dump packets:
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from ryu.lib import pcaplib
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class SimpleSwitch13(app_manager.RyuApp):
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OFP_VERSIONS = [ofproto_v1_3.OFP_VERSION]
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def __init__(self, *args, **kwargs):
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super(SimpleSwitch13, self).__init__(*args, **kwargs)
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self.mac_to_port = {}
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# Creating an instance with a PCAP filename
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self.pcap_pen = Writer(open('mypcap.pcap', 'wb'))
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@set_ev_cls(ofp_event.EventOFPPacketIn, MAIN_DISPATCHER)
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def _packet_in_handler(self, ev):
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msg = ev.msg
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# Dump the data packet into PCAP file
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self.pcap_pen.write_pkt(msg.data)
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pkt = packet.Packet(msg.data)
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Sample usage of reading PCAP files:
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from ryu.lib import pcaplib
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from ryu.lib.packet import packet
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frame_count = 0
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# Using the Reader iterator that yields packets in PCAP file
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for ts, buf in pcaplib.Reader(open('test.pcap', 'rb')):
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frame_count += 1
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pkt = packet.Packet(buf)
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eth = pkt.get_protocols(ethernet.ethernet)[0]
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dst = eth.dst
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src = eth.src
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# print frames count, timestamp, ethernet src, ethernet dst
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# and raw packet.
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print frame_count, ts, dst, src, pkt
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"""
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import struct
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import sys
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import time
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class PcapFileHdr(object):
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"""
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Global Header
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typedef struct pcap_hdr_s {
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guint32 magic_number; /* magic number */
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guint16 version_major; /* major version number */
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guint16 version_minor; /* minor version number */
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gint32 thiszone; /* GMT to local correction */
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guint32 sigfigs; /* accuracy of timestamps */
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guint32 snaplen; /* max length of captured packets,
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in octets */
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guint32 network; /* data link type */
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} pcap_hdr_t;
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Magic Number |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Version Major | Version Minor |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Thiszone |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Sigfigs |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Snaplen |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Network |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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File Format
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"""
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_FILE_HDR_FMT = None
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def __init__(self, magic='\xd4\xc3\xb2\xa1', version_major=2,
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version_minor=4, thiszone=0, sigfigs=0, snaplen=0,
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linktype=0):
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self.magic = magic
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self.version_major = version_major
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self.version_minor = version_minor
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self.thiszone = thiszone
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self.sigfigs = sigfigs
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self.snaplen = snaplen
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self.linktype = linktype
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@classmethod
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def parser(cls, buf):
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if buf[:4] == '\xa1\xb2\xc3\xd4':
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# Big Endian
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cls._FILE_HDR_FMT = '>IHHIIII'
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byteorder = '>'
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elif buf[:4] == '\xd4\xc3\xb2\xa1':
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# Little Endian
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cls._FILE_HDR_FMT = '<IHHIIII'
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byteorder = '<'
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else:
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raise Exception('Invalid pcap file.')
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(magic, version_major, version_minor, thiszone, sigfigs,
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snaplen, linktype) = struct.unpack_from(cls._FILE_HDR_FMT, buf)
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hdr = cls(magic, version_major, version_minor, thiszone, sigfigs,
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snaplen, linktype)
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return hdr, byteorder
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def serialize(self, fmt):
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return struct.pack(fmt, self.magic, self.version_major,
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self.version_minor, self.thiszone,
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self.sigfigs, self.snaplen, self.linktype)
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class PcapPktHdr(object):
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"""
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Record (Packet) Header
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typedef struct pcaprec_hdr_s {
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guint32 ts_sec; /* timestamp seconds */
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guint32 ts_usec; /* timestamp microseconds */
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guint32 incl_len; /* number of octets of packet
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saved in file */
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guint32 orig_len; /* actual length of packet */
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} pcaprec_hdr_t;
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0 1 2 3
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0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Timestamp Seconds |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Timestamp Microseconds |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Number of octets of saved in file |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| Actual length of packet |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Record (Packet) Header Format
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"""
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_PKT_HDR_FMT = None
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def __init__(self, ts_sec=0, ts_usec=0, incl_len=0, orig_len=0):
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self.ts_sec = ts_sec
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self.ts_usec = ts_usec
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self.incl_len = incl_len
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self.orig_len = orig_len
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@classmethod
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def parser(cls, byteorder, buf):
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if not buf:
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raise IndexError('No data')
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cls._PKT_HDR_FMT = byteorder + 'IIII'
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PKT_HDR_LEN = struct.calcsize(cls._PKT_HDR_FMT)
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(ts_sec, ts_usec, incl_len,
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orig_len) = struct.unpack_from(cls._PKT_HDR_FMT, buf)
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hdr = cls(ts_sec, ts_usec, incl_len, orig_len)
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# print repr(buf[0:16])
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return hdr, buf[PKT_HDR_LEN:PKT_HDR_LEN + incl_len]
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def serialize(self, fmt):
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return struct.pack(fmt, self.ts_sec, self.ts_usec,
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self.incl_len, self.orig_len)
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class Reader(object):
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_FILE_HDR_FMT = '>IHHIIII'
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_PKT_HDR_FMT = '>IIII'
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_PKT_HDR_LEN = struct.calcsize(_PKT_HDR_FMT)
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_FILE_HDR_FMT_LEN = struct.calcsize(_FILE_HDR_FMT)
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def __init__(self, file_obj):
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self._fp = file_obj
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# self.__filename = filename
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self._file_byteorder = None
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self._hdr_data = None
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self.incl_len_pos = 0
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def __iter__(self):
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buf = self._fp.read(Reader._FILE_HDR_FMT_LEN)
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# Only Read PCAP file from 0 to 24th byte
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(filehdr, self._file_byteorder) = PcapFileHdr.parser(buf)
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# self._fp.seek(Reader._FILE_HDR_FMT_LEN)
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# Read PCAP file from 24th byte to EOF
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self._hdr_data = self._fp.read()
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self._fp.close()
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return self
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def next(self):
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try:
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pkt_hdr, pkt_data = PcapPktHdr.parser(self._file_byteorder,
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self._hdr_data
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[self.incl_len_pos:])
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next_pos = pkt_hdr.incl_len + Reader._PKT_HDR_LEN
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self.incl_len_pos += next_pos
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except IndexError:
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raise StopIteration
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return float(pkt_hdr.ts_sec + (pkt_hdr.ts_usec / 1e6)), pkt_data
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class Writer(object):
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def __init__(self, file_obj, snaplen=65535, linktype=1):
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self._f = file_obj
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self._write_pcap_file_hdr(snaplen, linktype)
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def _write_pcap_file_hdr(self, snaplen, linktype):
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if sys.byteorder == 'little':
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pcap_file_hdr = PcapFileHdr(magic=0xa1b2c3d4,
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snaplen=snaplen,
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linktype=linktype)
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p = pcap_file_hdr.serialize(fmt='<IHHIIII')
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else:
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pcap_file_hdr, byteorder = PcapFileHdr(magic=0xd4c3b2a1,
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naplen=snaplen,
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linktype=linktype)
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p = pcap_file_hdr.serialize(fmt='>IHHIIII')
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self._f.write(str(p))
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def _write_pkt_hdr(self, ts, buf_str_len):
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sec = int(ts)
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if sec == 0:
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usec = 0
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else:
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usec = int(ts * 1e6) % int(ts)
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if sys.byteorder == 'little':
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# usec = int(ts * 1e6) % int(ts)
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# old_usec = int((float(ts) - int(ts)) * 1e6)
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pc_pkt_hdr = PcapPktHdr(ts_sec=sec,
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ts_usec=usec,
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incl_len=buf_str_len,
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orig_len=buf_str_len)
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p = pc_pkt_hdr.serialize(fmt='<IIII')
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else:
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pc_pkt_hdr = PcapPktHdr(ts_sec=sec,
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ts_usec=usec,
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incl_len=buf_str_len,
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orig_len=buf_str_len)
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p = pc_pkt_hdr.serialize(fmt='>IIII')
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self._f.write(str(p))
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def write_pkt(self, buf, ts=None):
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if ts is None:
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ts = time.time()
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buf_str = str(buf)
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buf_str_len = len(buf_str)
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self._write_pkt_hdr(ts, buf_str_len)
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self._f.write(buf_str)
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def __del__(self):
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self._f.close()
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