python's scapy library, example of sending/receiving packets to/from a network card.

#! usr/bin/env python
# -*- coding:utf-8 -*-
import os
import sys
import re
import struct
import string
from  import *
import subprocess

conf.use_pcap = True 

'''
cmd
python
from  import *
ls(Ether())
ls(IP())
ls(ICMP())
send(IP(dst='1.2.3.4')/ICMP())
sendp(Raw("zhongxing"), iface='eth15', loop=1, inter=0.2, verbose=False)
set up inter 参数来set up发送相邻两个包直接的时间间隔
set up timeout 参数来set up等待应答的超时时间
set up retry 参数来set up重试次数。
'''


print u"Implementing NIC Packet Sending."
target = []
for i in range(1,len()):
  m = [i].split('=')
  if m[0]=='-t':
    (m[1])
  if m[0]=='-ip':
    (m[1])
  if m[0]=='-mac':
    (m[1])
print 'test -- ',target
print

print u'Get the iface of the network card'
eth_local = []
a = repr().split('\n')
for x in a:
  b = []
  b = (' ')
  for y in b:
    if ('eth', y):
      eth_local.append(y)
print u'De-duplication'
c = []
(eth_local[0])
for i in range(0,len(eth_local),1):
  m = 0
  for j in range(0,len(c),1):
    if c[j] == eth_local[i]:
      m += 1
  if m==0:
    (eth_local[i])
print c #['eth15', 'eth21', 'eth17']

print u'Create Layer 2 message'
src_mac = '00:00:11:11:22:22'
dst_mac = '00:00:22:22:11:11'
dst_ip = '1.2.3.4'
src_ip = '5.6.7.8'
src_port = 1234
dst_port = 5678

##ls()
##ls(IP())
##IP().show()
##lsc()
pack_ip = IP(dst=dst_ip, src=src_ip, proto=1)
##ls(ICMP())
##ls(UDP())
pack_icmp = ICMP(type=8)
##ls(Ether())
pack_ether = Ether(dst=dst_mac, src=src_mac, type=0x0800)
info = Raw('zhongxing')
t = str(pack_ether/pack_ip/pack_icmp/info)
s = Ether(t)
print u'The message to be sent is:',
eth = c[1]
print u'The sent NIC iface is %s\n' % eth

print u'--------- start listening - send icmp - sniff icmp - close listening ----------'
print u'--------- started listening to -------------'
L2socket = conf.L2listen
listen_socket = L2socket(type=ETH_P_ALL, iface=eth)
print listen_socket
print conf.L2listen

#### startup grab bag
##cmd='C:\Program Files (x86)\Wireshark\'
##card_id = str(1)
##cap_file = str('H:\python\')
##args = [cmd,"-i "+card_id,"-w",cap_file]
##print "*DEBUG*",args
##p=(args)


print u'---------sendp()function call----------'
sendp(s,iface=eth, verbose=False)

##print u'---------srp() function call ----------'
The ##sr function is at the heart of Scapy, and returns two lists.
## The first list is the packets for which an answer was received and their corresponding answers.
## The second list is of packets for which no answer was received.
## Often, we need to call other functions to make the two return values more readable.
##help(srp)
##p = srp(s,iface=c[1], verbose=False)
##print ()

print u'--------- sniff, filter, save pcap, read pcap ----------'
##print sniff.__doc__
##pkts = sniff(iface = 'eth15',filter = 'icmp',count = 3, prn=lambda x: ())
ip = '172.10.0.1'
(["", ip]) # Offer to sniff
##Ether / IP / ICMP 172.10.1.124 > 172.10.0.1 echo-request 0 / Raw
##Ether / IP / ICMP 172.10.0.1 > 172.10.1.124 echo-reply 0 / Raw
##Ether / IP / ICMP 172.10.1.124 > 172.10.0.1 echo-request 0 / Raw
##listen_socket1 = L2socket(listen_socket)
##pkts = sniff(iface = eth,filter = 'icmp',count = 20, timeout = 10, L2socket=listen_socket)
pkts = sniff(iface = eth, filter = 'icmp', count = 20, timeout = 10) 
try:
  if 0 < len(pkts):
    print u'--------- sniffs the message ----------'
    ##pkts[0].show()
    wrpcap('',pkts)
    read_pkts = rdpcap('')
    print read_pkts[0]

    print u'---------------exportsbase64Data in coded format---------------'
    export_object(str(pkts[0]))

    print u'--------------- converted to base64 encoded format data ---------------'
    newPkt = import_object('eNprYAqN+Q8GGp/TOCfN5GBwZWDwc/nCwNAgOItrDRdjLxD/Z+gEQitpgwvijAIMjAxgoODmAYLO\
    /m7ebq6ubs7+ri6uAa5+YNrf2dHREaiEgbGQUQ8AnjEcMQ==')
    print newPkt
    s = Ether(newPkt)
    print u'The message to be sent is:',
    sendp(s,iface=eth, verbose=False)
  else:
    print u'--------- did not sniff the message ----------'
except:
  pass
finally:
  print u'--------- shut down listening to -------------'
  listen_socket.close()