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Send RAW Packets

Mininet provides tools such as ping, which makes it easy to send packets without ARP, etc. However, in experiments with real devices such as the Wedge Switch, you may want to send arbitrary packets from Wedge itself (OpenNetworkLinux) or a Windows/Mac connected to the Wedge port. Here are the tools for that.

rawsend.py - for Linux

In a Linux environment, you can use the rawsend.py included in this tutorial.

import socket
iface = 's1-eth1'
dstMac = b'\x01\x01\x01\x01\x01\x01'
srcMac = b'\x02\x02\x02\x02\x02\x02'
proto = b'\x88\xb5' # protocol type is IEEE Local Experimental
packet = dstMac + srcMac + proto + "012345678901234567890123456789012345678901234567890123456789"
s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(3)) # 3:ETH_P_ALL
s.bind((iface, 0))
s.send(packet)
print('Packet sent.')
s.close()

You can simply execute it with python rawsend.py, but you can easily use it in Mininet environment as follows.

mininet> sh cat > rawsend.py
import socket
(snip...)
s.close()
mininet> sh python rawsend.py
Packet sent.
mininet>

I will give you the monitoring results.

root@cc44475855d7:~#  tcpdump -XX -i s1-eth1
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on s1-eth1, link-type EN10MB (Ethernet), capture size 262144 bytes
04:00:37.407342 02:02:02:02:02:02 (oui Unknown) > 01:01:01:01:01:01 (oui Unknown), ethertype Unknown (0x88b5), length 74: 
	0x0000:  0101 0101 0101 0202 0202 0202 88b5 3031  ..............01
	0x0010:  3233 3435 3637 3839 3031 3233 3435 3637  2345678901234567
	0x0020:  3839 3031 3233 3435 3637 3839 3031 3233  8901234567890123
	0x0030:  3435 3637 3839 3031 3233 3435 3637 3839  4567890123456789
	0x0040:  3031 3233 3435 3637 3839                 0123456789

rawsend.c - for MacOS

On MacOS, you can use rawsend.c included in this tutorial. It would be simple if you could use the Python program above, but AF_PACKET is only available on Linux. On BSD-like OSs you need to code using BPF (Berkley Packet Filters), or pcap library, as follows:

#include <stdlib.h> 
#include <stdio.h> 
#include <pcap.h>
int main(int argc, char **argv) {
    pcap_t *fp;
    char errbuf[PCAP_ERRBUF_SIZE]; 
    u_char packet[100];
    int i;

    /* Check the validity of the command line */
    if (argc != 2){
        printf("usage: %s interface", argv[0]); return 1;
    }
    /* Open the adapter */
    if ((fp = pcap_open_live(
            argv[1], // name of the device
            65536, // portion of the packet to capture. It doesn’t matter in this case 
            1, // promiscuous mode (nonzero means promiscuous)
            1000, // read timeout
            errbuf // error buffer
            )) == NULL) {
        fprintf(stderr,"\nUnable to open the adapter. %s is not supported\n", argv[1]);
        return 2;
    }
    // Setting dstMac to 01:01:01:01:01:01
    for(i = 0; i < 6; i++) packet[i]=0x01;
    // Setting srcMac to 02:02:02:02:02:02
    for(i = 0; i < 6; i++) packet[6+i]=0x02;
    // Fill the rest of the packet with data
    packet[12]=0x88; packet[13]=0xb5; // protocol type is IEEE Local Experimental
    // Fill the rest of the packet with data
    for(i = 0; i < 60; i++) packet[14 + i]= (u_char)('0' + (i % 10));

    // Send packet
    if (pcap_sendpacket(fp, packet, 6 + 6 + 2 + 60) != 0) {
        fprintf(stderr,"\nError sending the packet: %s\n", pcap_geterr(fp)); return 1;
    }
    printf("Packet sent.\n"); 
    pcap_close(fp);

    return 0;
}

source: https://tuprints.ulb.tu-darmstadt.de/6243/1/TR-18.pdf

Compile and execute as follows.

$ cc -o rawsend -lpcap rawsend.c
$

$ ./rawsend en0
Packet sent.
$