Please note: This respository has become staled due to relocation to GitLab. Visit https://gitlab.com/mike01/pypacker for up-to-date versions.
This is Pypacker: The fastest and simplest packet manipulation lib for Python. It lets you create packets manually by defining every aspect of all header data, dissect packets by parsing raw packet bytes, sending/receiving packets on different layers and intercepting packets.
What you can do with Pypacker
Create Packets giving specific values or take the defaults:
from pypacker.layer3.ip import IP from pypacker.layer3.icmp import ICMP ip = IP(src_s="127.0.0.1", dst_s="192.168.0.1", p=1) +\ ICMP(type=8) +\ ICMP.Echo(id=123, seq=1, body_bytes=b"foobar") # output packet print("%s" % ip) IP(v_hl=45, tos=0, len=2A, id=0, off=0, ttl=40, p=1, sum=3B29, src=b'\x7f\x00\x00\x01', dst=b'\xc0\xa8\x00\x01', opts=, handler=icmp) ICMP(type=8, code=0, sum=C03F, handler=echo) Echo(id=7B, seq=1, ts=0, bytes=b'foobar')
Read packets from file (pcap/tcpdump format), analyze it and write them back:
from pypacker import ppcap from pypacker.layer12 import ethernet from pypacker.layer3 import ip from pypacker.layer4 import tcp preader = ppcap.Reader(filename="packets_ether.pcap") pwriter = ppcap.Writer(filename="packets_ether_new.pcap", linktype=ppcap.DLT_EN10MB) for ts, buf in preader: eth = ethernet.Ethernet(buf) if eth[ethernet.Ethernet, ip.IP, tcp.TCP] is not None: print("%d: %s:%s -> %s:%s" % (ts, eth[ip.IP].src_s, eth[tcp.TCP].sport, eth[ip.IP].dst_s, eth[tcp.TCP].dport)) pwriter.write(eth.bin()) pwriter.close()
Intercept (and modificate) Packets eg for MITM:
# Add iptables rule: # iptables -I INPUT 1 -p icmp -j NFQUEUE --queue-balance 0:2 import time from pypacker import interceptor from pypacker.layer3 import ip, icmp # ICMP Echo request intercepting def verdict_cb(ll_data, ll_proto_id, data, ctx): ip1 = ip.IP(data) icmp1 = ip1[icmp.ICMP] if icmp1 is None or icmp1.type != icmp.ICMP_TYPE_ECHO_REQ: return data, interceptor.NF_ACCEPT echo1 = icmp1[icmp.ICMP.Echo] if echo1 is None: return data, interceptor.NF_ACCEPT pp_bts = b"PYPACKER" print("changing ICMP echo request packet") echo1.body_bytes = echo1.body_bytes[:-len(pp_bts)] + pp_bts return ip1.bin(), interceptor.NF_ACCEPT ictor = interceptor.Interceptor() ictor.start(verdict_cb, queue_ids=[0, 1, 2]) print("now sind a ICMP echo request to localhost: ping 127.0.0.1") time.sleep(999) ictor.stop()
Send and receive packets:
# send/receive raw bytes from pypacker import psocket from pypacker.layer12 import ethernet from pypacker.layer3 import ip psock = psocket.SocketHndl(mode=psocket.SocketHndl.MODE_LAYER_2, timeout=10) for raw_bytes in psock: eth = ethernet.Ethernet(raw_bytes) print("Got packet: %r" % eth) eth.reverse_address() eth.ip.reverse_address() psock.send(eth.bin()) # stop on first packet break psock.close()
# send/receive using filter from pypacker import psocket from pypacker.layer3 import ip from pypacker.layer4 import tcp packet_ip = ip.IP(src_s="127.0.0.1", dst_s="127.0.0.1") + tcp.TCP(dport=80) psock = psocket.SocketHndl(mode=psocket.SocketHndl.MODE_LAYER_3, timeout=10) def filter_pkt(pkt): return pkt.ip.tcp.sport == 80 psock.send(packet_ip.bin(), dst=packet_ip.dst_s) pkts = psock.recvp(filter_match_recv=filter_pkt) for pkt in pkts: print("got answer: %r" % pkt) psock.close()
# Send/receive based on source/destination data from pypacker import psocket from pypacker.layer3 import ip from pypacker.layer4 import tcp packet_ip = ip.IP(src_s="127.0.0.1", dst_s="127.0.0.1") + tcp.TCP(dport=80) psock = psocket.SocketHndl(mode=psocket.SocketHndl.MODE_LAYER_3, timeout=10) packets = psock.sr(packet_ip, max_packets_recv=1) for p in packets: print("got layer 3 packet: %s" % p) psock.close()
- Create network packets on different OSI layers using keywords like MyPacket(value=123) or raw bytes MyPacket(b"value")
- Concatination of layers via "+" like packet = layer1 + layer2
- Fast access to layers via packet[tcp.TCP] or packet.sublayerXYZ.tcp notation
- Readable packet structure using print(packet) or similar statements
- Read/store packets via Pcap/tcpdump file reader/writer
- Live packet reading/writing using a wrapped socket API
- Auto Checksum calculation capabilities
- Intercept Packets using NFQUEUE targets
- Easily create new protocols (see FAQ below)
- Python 3.x (CPython, Pypy, Jython or whatever Interpreter)
- Optional (for interceptor):
- Linux based system
- NFQUEUE target support in kernel for packet intercepting
- libnetfilter_queue library (see http://www.netfilter.org/projects/libnetfilter_queue)
- Download/clone pypacker -> python setup.py install (newest version)
- pip install pypacker (synched to master on major version changes)
See examples/ and tests/test_pypacker.py.
Tests are executed as follows:
- Add Pypacker directory to the PYTHONPATH.
- cd pypacker
- export PYTHONPATH=$PYTHONPATH:$(pwd)
- execute tests
- python tests/test_pypacker.py
Performance test results: pypacker
orC = Intel Core2 Duo CPU @ 1,866 GHz, 2GB RAM, CPython v3.6 orP = Intel Core2 Duo CPU @ 1,866 GHz, 2GB RAM, Pypy 5.10.1 rounds per test: 10000 ===================================== >>> parsing (IP + ICMP) orC = 86064 p/s orP = 208346 p/s >>> creating/direct assigning (IP only header) orC = 41623 p/s orP = 59370 p/s >>> bin() without change (IP) orC = 170356 p/s orP = 292133 p/s >>> output with change/checksum recalculation (IP) orC = 10104 p/s orP = 23851 p/s >>> basic/first layer parsing (Ethernet + IP + TCP + HTTP) orC = 62748 p/s orP = 241047 p/s >>> changing Triggerlist element value (Ethernet + IP + TCP + HTTP) orC = 101552 p/s orP = 201994 p/s >>> changing Triggerlist/text based proto (Ethernet + IP + TCP + HTTP) orC = 37249 p/s orP = 272972 p/s >>> direct assigning and concatination (Ethernet + IP + TCP + HTTP) orC = 7428 p/s orP = 14315 p/s >>> full packet parsing (Ethernet + IP + TCP + HTTP) orC = 6886 p/s orP = 17040 p/s
Performance test results: pypacker vs. dpkt vs. scapy
Comparing pypacker, dpkt and scapy performance (parsing Ethernet + IP + TCP + HTTP) orC = Intel Core2 Duo CPU @ 1,866 GHz, 2GB RAM, CPython v3.6 orC2 = Intel Core2 Duo CPU @ 1,866 GHz, 2GB RAM, CPython v2.7 rounds per test: 10000 ===================================== >>> testing pypacker parsing speed orC = 17938 p/s >>> testing dpkt parsing speed orC = 12431 p/s >>> testing scapy parsing speed orC2 = 726 p/s
Q: Where should I start learn to use Pypacker?
A: If you allready know Scapy starting by reading the examples should be OK. Otherwise there is a general introduction to pypacker included at the doc's which shows the usage and concepts of pypacker.
Q: How fast is pypacker?
A: See results above. For detailed results on your machine execute tests.
Q: Is there any documentation?
A: Pypacker is based on code of dpkt, which in turn didn't have any official and very little internal code documentation. This made understanding of the internal behaviour tricky. After all the code documentation was pretty much extended for Pypacker. Documentation can be found in these directories and files:
- examples/ (many examples showing the usage of Pypacker)
- wiki (general intro into pypacker)
- pypacker.py (general Packet structure)
Protocols itself (see layerXYZ) generally don't have much documentation because those are documented by their respective RFCs/official standards.
Q: Which protocols are supported?
A: Currently minimum supported protocols are: Ethernet, Radiotap, IEEE80211, ARP, DNS, STP, PPP, OSPF, VRRP, DTP, IP, ICMP, PIM, IGMP, IPX, TCP, UDP, SCTP, HTTP, NTP, RTP, DHCP, RIP, SIP, Telnet, HSRP, Diameter, SSL, TPKT, Pmap, Radius, BGP
Q: How are protocols added?
A: Short answer: Extend Packet class and add the class variable
__hdr__ to define header fields.
Long answer: See examples/examples_new_protocol.py for a very complete example.
Q: How can I contribute to this project?
A: Please use the Github bug-tracker for bugs/feature request. Please read the bugtracker for already known bugs before filing a new one. Patches can be send via pull request.
Q: Under which license Pypacker is issued?
A: It's the GPLv2 License (see LICENSE file for more information).
Q: Are there any plans to support [protocol xyz]?
A: Support for particular protocols is added to Pypacker as a result of people contributing that support - no formal plans for adding support for particular protocols in particular future releases exist.
Q: There is problem xyz with Pypacker using Windows 3.11/XP/7/8/mobile etc. Can you fix that?
A: The basic features should work with any OS. Optional ones may make trouble (eg interceptor) and there will be no support for that. Why? Because quality matters and I won't give support for inferior systems. Think twice before chosing an operating system and deal with the consequences; don't blame others for your decision. Alternatively: give me monetary compensation and I'll see what I can do (;
- For maxmimum performance start accessing attributes at lowest level e.g. for filtering:
# This will lazy parse only needed layers behind the scenes if ether.src == "...": ... elif ip.src == "...": ... elif tcp.sport == "...": ...
- Avoid to convert packets using the "%s" or "%r" format as it triggers parsing behind the scene:
pkt = Ethernet() + IP() + TCP() # This parses ALL layers packet_print = "%s" % pkt
- Avoid searching for a layer using single-value index-notation via pkt[L] as it parses all layers until L is found or highest layer is reached:
packet_found = pkt[Telnet] # Alternative: Use multi-value index-notation. This will stop parsing at any non-matching layer: packet_found = pkt[Ethernet,IP,TCP,Telnet]
- For even more performance disable auto fields (affects calling bin(...)):
pkt = ip.IP(src_s="188.8.131.52", dst_s="184.108.40.206") + tcp.TCP() # Disable checksum calculation (and any other update) for IP and TCP (only THIS packet instance) pkt.sum_au_active = False pkt.tcp.sum_au_active = False bts = pkt.bin(update_auto_fields=False)
- Enlarge receive/send buffers to get max performance. This can be done using the following commands (taken from: http://www.cyberciti.biz/faq/linux-tcp-tuning/):
sysctl -w net.core.rmem_max=12582912 sysctl -w net.core.rmem_default=12582912 sysctl -w net.core.wmem_max=12582912 sysctl -w net.core.wmem_default=12582912 sysctl -w net.core.optmem_max=2048000 sysctl -w net.core.netdev_max_backlog=5000 sysctl -w net.unix.max_dgram_qlen=1000 sysctl -w net.ipv4.tcp_rmem="10240 87380 12582912" sysctl -w net.ipv4.tcp_wmem="10240 87380 12582912" sysctl -w net.ipv4.tcp_mem="21228 87380 12582912" sysctl -w net.ipv4.udp_mem="21228 87380 12582912" sysctl -w net.ipv4.tcp_window_scaling=1 sysctl -w net.ipv4.tcp_timestamps=1 sysctl -w net.ipv4.tcp_sack=1
- Assemblation of TCP/UDP streams can be done by tshark using pipes with "-i -" and "-z follow,prot,mode,filter[,range]"