问题
Scapy has a sendpfast
function that sends packets using tcpreplay. However, this function first creates a temporary pcap file and then calls tcpreplay on that. This adds too much delay. Is there anyway to bypass it and directly send data to tcpreplay. I know that tcpreplay can read data from STDIN.
Context: I want to generate large traffic (with different srcIP) every second and send it through network. One option is to save all traffic with timestamps in a giant pcap file and run tcpreplay. Another option is to send data every second.
回答1:
Not sure whether or not avoiding temporary file will be enough, but still, here is a way:
#! /usr/bin/env python
from scapy.all import *
def pkt2pcap(p):
sec = int(p.time)
usec = int(round((p.time-sec)*1000000))
s = str(p)
caplen = len(s)
return struct.pack("IIII", sec, usec, caplen, caplen) + s
# adapted from Scapy's sendpfast
def mysendpfast(x, pps=None, mbps=None, realtime=None, loop=0, file_cache=False, iface=None):
"""Send packets at layer 2 using tcpreplay for performance
pps: packets per second
mpbs: MBits per second
realtime: use packet's timestamp, bending time with realtime value
loop: number of times to process the packet list
file_cache: cache packets in RAM instead of reading from disk at each iteration
iface: output interface """
if iface is None:
iface = conf.iface
argv = [conf.prog.tcpreplay, "--intf1=%s" % iface ]
if pps is not None:
argv.append("--pps=%i" % pps)
elif mbps is not None:
argv.append("--mbps=%i" % mbps)
elif realtime is not None:
argv.append("--multiplier=%i" % realtime)
else:
argv.append("--topspeed")
if loop:
argv.append("--loop=%i" % loop)
if file_cache:
argv.append("--enable-file-cache")
argv.append("-")
try:
f = subprocess.Popen(argv, stdin=subprocess.PIPE)
# PCAP header
p = x.next()
f.stdin.write(struct.pack("IHHIIII", 0xa1b2c3d4L,
2, 4, 0, 0, MTU,
conf.l2types[p.__class__]))
# Let's send
f.stdin.write(pkt2pcap(p))
for p in x:
f.stdin.write(pkt2pcap(p))
f.stdin.close()
f.communicate()
except KeyboardInterrupt:
log_interactive.info("Interrupted by user")
except Exception,e:
log_interactive.error("while trying to exec [%s]: %s" % (argv[0],e))
来源:https://stackoverflow.com/questions/19760102/scapy-and-tcpreplay-bypass-temporary-file-for-performance