packet

I am using the same UDP socket for sending and receiving data. I am wondering if packet queuing for DGRAM sockets is already present, or do we have to handle it separately. If the user code has to handle queueing, how is it done? Do we have separate threads to recvfrom for the socket and put the packet in the reciver_queue and to sendto from another sending_queue? An example code will be absolutely awesome. Thanks for your help. There is a packet queue. However when the packet queue is filled then UDP packets start getting discarded. When they are discarded they are lost forever so make sure

In C if you have a certain type of packet, what you generally do is define some struct and cast the char * into a pointer to the struct. After this you have direct programmatic access to all data fields in the network packet. Like so : struct rdp_header { int version; char serverId[20]; }; When you get a network packet you can do the following quickly : char * packet; // receive packet rdp_header * pckt = (rdp_header * packet); printf("Servername : %20.20s\n", pckt.serverId); This technique works really great for UDP based protocols, and allows for very quick and very efficient packet parsing

I'm trying to send UDP Packets with scapy with the following command: >> send(IP(dst="127.0.0.1",src="111.111.111.111")/UDP(dport=5005)/"Hello") . Sent 1 packets. And from tcpdump I can see: 22:02:58.384730 IP 111.111.111.111.domain > localhost.5005: [|domain] I'm trying to receive this packet with the following code: import socket UDP_IP = "127.0.0.1" UDP_PORT = 5005 sock = socket.socket(socket.AF_INET, # Internet socket.SOCK_DGRAM) # UDP sock.bind((UDP_IP, UDP_PORT)) while True: data, addr = sock.recvfrom(1024) # buffer size is 1024 bytes print "received message:", data But cannot receive

Can I insert image or document (in MBs) as a data in packet using scapy? This is what I did to send data. data = "University of texas at San Antonio" a = IP(dst="129.132.2.21")/TCP()/data send(a) Yes, you can send raw data like this. In this example, data will be ASCII encoded. >>> data = 'University of Texas at San Antonio' >>> a = IP(dst='129.132.2.21') / TCP() / Raw(load=data) >>> sendp(a) 来源： https://stackoverflow.com/questions/6605118/adding-payload-in-packet

I'm looking to write a small program which will intercept network packets (on the local machine) and modify them before they go out on the network. I need to be able to modify the headers as well, not just the data. I've already looked through several possibilities but am unsure which one is best to pursue. There are open source packet filters out there, but filtering only seems to be able to either allow or reject packets, not much else. The other solution would be to write an NDIS intermediate driver, but writing drivers is a beyond me. Even the simple pass-thru example in the WinDDK is