I have a device which is sending packet with its own specific construction (header, data, crc) through its ethernet port.
What I would like to do is to communicate with this device using a Raspberry and Python 3.x.
I am already able to send Raw ethernet packet using the "socket" Library, I've checked with wireshark on my computer and everything seems to be transmitted as expected.
But now I would like to read incoming raw packet sent by the device and store it somewhere on my RPI to use it later.
I don't know how to use the "socket" Library to read raw packet (I mean layer 2 packet), I only find tutorials to read higher level packet like TCP/IP.
What I would like to do is Something similar to what wireshark does on my computer, that is to say read all raw packet going through the ethernet port.
Thanks,
Alban
Did you try using ettercap package (ettercap-graphical)?
It should be available with apt.
Alternatively you can try using TCPDump (Java tool) or even check ip tables
Related
how can i create a spoofed UDP packet using python sockets,without using scapy library.
i have created the socket like this
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) # UDP
sock.sendto(bytes('', "utf-8"), ('192.168.1.9', 7043))# 192.168.1.9dest 7043 dest port
This is one of the first results for google searches like "spoofing udp packet python" so I am going to expand #Cukic0d's answer using scapy.
Using the scapy CLI tool (some Linux distributions package it separately to the scapy Python library ):
pkt = IP(dst="1.1.1.1")/UDP(sport=13338, dport=13337)/"fm12abcd"
send(pkt)
This sends a UDP Packet to the IP 1.1.1.1 with the source port 13338, destination port 13337 and the content fm12abcd.
If you need to a certain interface for some reason (like sending over a VPN that isn't your default route) you can use send(pkt, iface='tun0') to specify it.
One difference to #Cukic0d's answer is that this solution is more flexible by sending a layer 3 packet with send instead of a layer 2 packet with sendp. So it isn't necessary to prepend the correct Ethernet header with Ether() which can cause issues in some scenarios, e.g.:
WARNING: Could not get the source MAC: Unsupported address family (-2) for interface [tun0]
WARNING: Mac address to reach destination not found. Using broadcast.
I think you mean changing the source and destination addresses from the IP layer (on which the UDP layer is based).
To do so, you will need to use raw sockets. (SOCK_RAW), meaning that you have to build everything starting from the Ethernet layer to the UDP layer.
Honestly, without scapy, that’s a lot of hard work. If you wanted to use scapy, it would take 2 lines:
pkt = Ether()/IP(src=“...”, dst=“...”)/UDP()/...
sendp(pkt)
I really advice you to use scapy. The code itself is quite small so I don’t see a reason not to use it. It’s defiantly the easiest in python
I read many articles and found how to send custom packet based on IP using socket(AF_INET, SOCK_RAW, IPPROTO_RAW). But I want to send completely custom packet starting from Ethernet header. I can't send ARP packet if I can't form Ethernet header cause ARP don't based IP. Please, help!
P.S. I am on Windows 7, not Linux :(
In python, the easiest way is to use the cross-platform scapy library. It’s well known for that
Scapy
You can sniff, send.... lots of packets, add your own protocols, use existing ones... and it works on nearly all platforms. (On windows, it uses Npcap/Winpcap)
You can then build an ARP packet using
from scapy.all import *
pkt = ARP()
pkt.show()
sendp(Ether(dst=..., src=...)/pkt)
Which will create such packets
###[ ARP ]###
hwtype= 0x1
ptype= 0x800
hwlen= 6
plen= 4
op= who-has
hwsrc= 00:50:56:00:1e:3d
psrc= 212.83.148.19
hwdst= 00:00:00:00:00:00
pdst= 0.0.0.0
To build the packet, use the / operator
ether = Ether()
ether.src = “00:00:00:00:00:00”
ether.dst = “ff:ff:ff:ff:ff:ff”
arp = ARP()
[edit arp.psrc, arp.pdst, arp.hwsrc, arp.hwdst]
packet = ether/arp
sendp(packet) # sens packet on layer 2
Have a look at its Scapy documentation
There's no cross-platform way to do what you want, of course.
Python is just passing these values through to the underlying C API. So, on a platform with a complete BSD sockets API including the packet interface, you can just use AF_PACKET and the other appropriate flags. (I think you'd want ETH_P_ALL or ETH_P_802_2 rather than IPPROTO_RAW, or you might want SOCK_DGRAM… anyway, read your platform's man packet and figure it out based on what you actually need to do.) On Linux, at least most of these flags should be available on the SOCKET module; on other Unixes, they often don't get picked up, so you have to manually look them up in the system headers and use hardcoded constant ints in your code.
Unfortunately, if you're on Windows, this doesn't do any good. While WinSock has a feature they call TCP/IP Raw Sockets, accessed via SOCK_RAW, and recent versions of Python do expose this, it's just an emulation of a small subset of what actual BSD sockets implementations can do, and doesn't offer any way to go below the IP level (hence the name of the feature).
Microsoft's solution to this used to be that you'd write a TDI provider with the DDK, which would implement whatever protocol you wanted to expose as another WinSock protocol, and then your application-level code could just use that protocol the same way it would use, e.g., TCP. From the linked document above, it looks like this is obsolete, but the replacement seems like the same idea but with different acronyms (and, presumably, different APIs).
On the other hand, I'm pretty sure Windows already comes with protocols for ARP, ICMP, and anything other protocols needed for its usermode tools (because they obviously can't be written around raw packets). I'm just not sure how to access them.
As far as I know, the usual alternative is to use WinPcap.
While this was originally designed to be a packet capture library, it also implements a complete link-level socket interface that you can use for sending and receiving raw frames.
And there are Python wrappers for it, like WinPcapy.
So, as long as you can require that the WinPcap driver be installed, you can write ARP code, etc., on Windows in Python. It's just different from doing it on Unix.
In fact, one of the examples on the front page of WinPcapY, "Easy Packet sending", should get you started:
from winpcapy import WinPcapUtils
# Build a packet buffer
# This example-code is built for tutorial purposes, for actual packet crafting use modules like dpkt
arp_request_hex_template = "%(dst_mac)s%(src_mac)s08060001080006040001" \
"%(sender_mac)s%(sender_ip)s%(target_mac)s%(target_ip)s" + "00" * 18
packet = arp_request_hex_template % {
"dst_mac": "aa"*6,
"src_mac": "bb"*6,
"sender_mac": "bb"*6,
"target_mac": "cc"*6,
# 192.168.0.1
"sender_ip": "c0a80001",
# 192.168.0.2
"target_ip": "c0a80002"
}
# Send the packet (ethernet frame with an arp request) on the interface
WinPcapUtils.send_packet("*Ethernet*", packet.decode("hex"))
I am sending packets using:
send(IP(dst="192.168.1.114")/fuzz(UDP()/NTP(version=4)), loop=1)
But I am not able to capture these packets in any other nearby machine (including the one with IP 192.168.1.114) which is on the same network. I am using wlan as my interface.
I also tried to sniff and then replay using scapy but I am still not able to capture those packets.
i would first try to capture the traffic on the sender machine with tcpdump while executing your program:
tcpdump -i any udp dst 192.168.1.114
if you can see the traffic leaving the source host it may be that it does not arrive on the target host. UDP packets are the first packets to be dropped by any network device and as it is the nature of UDP it wont get retransmitted. if you are sure the packet leaves the source verify if it arrives at the target:
tcpdump -i any upd dst 192.168.1.114
Another point to check is your firewall settings. It could be either on the source or target system that your firewall is blocking those requests.
I finally resolved this. Here is the checklist I made which might help others when dealing with replaying/fuzzing using scapy.
Check if all IP addresses you are dealing with are alive in the
network (use ping)
Understand the difference between send() (layer 3)and sendp() (layer 2)
If mutating existing packet make sure to
remove the checksum (using 'del') and recalculate the checksum
either using show2() or using str to convert packets to string
and then converting them back to packets
You should use Wireshark, or the sniff function in Scapy and make it pretty print the contents on the screen:
sniff(lambda x:x.show())
I want to know the number of packets and the packet size for each packet sent by every process in the host computer.
I have tried using psutil the library:
p=psutil.Process(pid)
process_connection=p.connections()
But it shows the address and port but no information about the packet.
psutil.net_io_counters()
This shows the bytes sent and received by the host.
How can I get this information using Python 2.7 and Windows 7?
Conceptually, you need to apply a packet sniffer for that. The process statistics do not collect (meta-)information about each and every packet sent by a process, that would be very inefficient with respect to both processing power and memory footprint.
Scapy is one of the popular packages providing packet sniffing from Python for unixes, but I don’t know about its support for windows or other packages which support windows.
Is there any way to send ARP packet on Windows without the use of another library such as winpcap?
I have heard that Windows XP SP2 blocks raw ethernet sockets, but I have also heard that raw sockets are only blocked for administrators. Any clarification here?
There is no way to do that in the general case without the use of an external library.
If there are no requirements on what the packet should contain (i.e., if any ARP packet will do) then you can obviously send an ARP request if you're on an Ethernet network simply by trying to send something to any IP on your own subnet (ensuring beforehand that the destination IP is not in the ARP cache by running an external arp -d tar.get.ip.address command), but this will probably not be what you want.
For more information about raw socket support see the TCP/IP Raw Sockets Docs page, specifically the Limitations on Raw Sockets section.
You could use the OpenVPN tap to send arbitrary packets as if you where using raw sockets.