python判断网络是否通

提供两种方法：

netstats.py

# -*- coding: gbk -*-import myarpimport osclass netStatus:    def internet_on(self,ip="192.168.150.1"):        os.system("arp -d 192.168.150.1")        if myarp.arp_resolve(ip, 0) == 0:   #使用ARP ping的方法            return True        else:            return False    def ping_netCheck(self, ip):           #直接ping的方法        os.system("arp -d 192.168.150.1")        cmd = "ping " +str(ip) + " -n 2"        exit_code = os.system(cmd)        if exit_code:            return False        return Trueif __name__ == "__main__":    net = netStatus()    print net.ping_netCheck("192.168.150.2")

myarp.py（这个是从ARP模块改来的）

"""ARP / RARP module (version 1.0 rev 9/24/2011) for Python 2.7Copyright (c) 2011 Andreas Urbanski.Contact the me via e-mail: [e-mail] module is a collection of functions to send out ARP (or RARP) queriesand replies, resolve physical addresses associated with specific ips andto convert mac and ip addresses to different representation formats. Italso allows you to send out raw ethernet frames of your preferred protocoltype. DESIGNED FOR USE ON WINDOWS.NOTE: Some functions in this module use winpcap for windows. Please makesure that wpcap.dll is present in your system to use them.LICENSING:This program is free software: you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation, either version 3 of the License, or(at your option) any later version.This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with this program.  If not, see <http://www.gnu.org/licenses/>"""__all__ = ['showhelp', 'find_device', 'open_device', 'close_device', 'send_raw',           'multisend_raw', 'arp_resolve', 'arp_reply', 'rarp_reply', 'mac_straddr',           'ip_straddr', 'ARP_REQUEST', 'ARP_REPLY', 'RARP_REQUEST', 'RARP_REPLY',           'FRAME_SAMPLE']""" Set this to True you wish to see warning messages """__warnings__ = Falsefrom ctypes import *import socketimport structimport timeFRAME_SAMPLE = """Sample ARP frame+-----------------+------------------------+| Destination MAC | Source MAC             |+-----------------+------------------------+| \\x08\\x06 (arp)  | \\x00\\x01  (ethernet)   |+-----------------+------------------------+| \\x08\\x00 (internet protocol)             |+------------------------------------------+| \\x06\\x04 (hardware size & protocol size) |+------------------------------------------+| \\x00\\x02 (type: arp reply)               | +------------+-----------+-----------------+| Source MAC | Source IP | Destination MAC |+------------+---+-------+-----------------+| Destination IP | ... Frame Length: 42 ...+----------------+"""""" Frame header bytes """ARP_REQUEST = "\x08\x06\x00\x01\x08\x00\x06\x04\x00\x01"ARP_REPLY = "\x08\x06\x00\x01\x08\x00\x06\x04\x00\x02"RARP_REQUEST = "\x80\x35\x00\x01\x08\x00\x06\x04\x00\x03"RARP_REPLY = "\x80\x35\x00\x01\x08\x00\x06\x04\x00\x04"""" Defines """ARP_LENGTH = 42RARP_LENGTH = 42DEFAULT = 0""" Look for wpcap.dll """try:    wpcap = cdll.wpcapexcept WindowsError:    print "Error loading wpcap.dll! Ensure that winpcap is properly installed."""" Loading Windows system libraries should not be a problem """try:    iphlpapi = windll.Iphlpapi    ws2_32 = windll.ws2_32except WindowsError:    """ Should it still fail """    print "Error loading windows system libraries!"""" Import functions """if wpcap:    """ Looks up for devices """    pcap_lookupdev = wpcap.pcap_lookupdev    """ Opens a device instance """    popen_live = wpcap.pcap_open_live    """ Sends raw ethernet frames """    pcap_sendpacket = wpcap.pcap_sendpacket    """ Close and cleanup """    pcap_close = wpcap.pcap_close""" Find the first device available for use. If this failsto retrieve the preferred network interface identifier,disable all other interfaces and it should work."""def find_device():    errbuf = create_string_buffer(256)    device = c_void_p    device = pcap_lookupdev(errbuf)    return device""" Get the handle to a network device. """def open_device(device=DEFAULT):    errbuf = create_string_buffer(256)    if device == DEFAULT:        device = find_device()    """ Get a handle to the ethernet device """    eth = popen_live(device, 4096, 1, 1000, errbuf)    return eth""" Close the device handle """def close_device(device):    pcap_close(device)""" Send a raw ethernet frame """def send_raw(device, packet):    if not pcap_sendpacket(device, packet, len(packet)):        return len(packet)""" Send a list of packets at the specified interval """def multisend_raw(device, packets=[], interval=0):    """ Bytes sent """    sent = 0    for p in packets:        sent += len(p)        send_raw(device, p)        time.sleep(interval)    """ Return the number of bytes sent"""    return sent""" Resolve the mac address associated with thedestination ip address"""def arp_resolve(destination, strformat=True, source=None):    mac_addr = (c_ulong * 2)()    addr_len = c_ulong(6)    dest_ip = ws2_32.inet_addr(destination)    if not source:        src_ip = ws2_32.inet_addr(socket.gethostbyname(socket.gethostname()))    else:        src_ip = ws2_32.inet_addr(source)    """    Iphlpapi SendARP prototype    DWORD SendARP(      __in     IPAddr DestIP,      __in     IPAddr SrcIP,      __out    PULONG pMacAddr,      __inout  PULONG PhyAddrLen    );    """    error = iphlpapi.SendARP(dest_ip, src_ip, byref(mac_addr), byref(addr_len))    return error""" Send a (gratuitous) ARP reply """def arp_reply(dest_ip, dest_mac, src_ip, src_mac):    """ Test input formats """    if dest_ip.find('.') != -1:        dest_ip = ip_straddr(dest_ip)    if src_ip.find('.') != -1:        src_ip = ip_straddr(src_ip)    """ Craft the arp packet """    arp_packet = dest_mac + src_mac + ARP_REPLY + src_mac + src_ip + \                 dest_mac + dest_ip    if len(arp_packet) != ARP_LENGTH:        return -1    return send_raw(open_device(), arp_packet)""" Include RARP for consistency :)"""def rarp_reply(dest_ip, dest_mac, src_ip, src_mac):    """ Test input formats """    if dest_ip.find('.') != -1:        dest_ip = ip_straddr(dest_ip)    if src_ip.find('.') != -1:        src_ip = ip_straddr(src_ip)    """ Craft the rarp packet """    rarp_packet = dest_mac + src_mac + RARP_REPLY + src_mac + src_ip + \                  src_mac + src_ip    if len(rarp_packet) != RARP_LENGTH:        return -1    return send_raw(open_device(), rarp_packet)""" Convert c_ulong*2 to a hexadecimal string or a printable asciistring delimited by the 3rd parameter"""def mac_straddr(mac, printable=False, delimiter=None):    """ Expect a list of length 2 returned by arp_query """    if len(mac) != 2:        return -1    if printable:        if delimiter:            m = ""            for c in mac_straddr(mac):                m += "%02x" % ord(c) + delimiter            return m.rstrip(delimiter)        return repr(mac_straddr(mac)).strip("\'")    return struct.pack("L", mac[0]) + struct.pack("H", mac[1])""" Convert address in an ip dotted decimal format to a hexadecimalstring """def ip_straddr(ip, printable=False):    ip_l = ip.split(".")    if len(ip_l) != 4:        return -1    if printable:        return repr(ip_straddr(ip)).strip("\'")    return struct.pack(        "BBBB",        int(ip_l[0]),        int(ip_l[1]),        int(ip_l[2]),        int(ip_l[3])    )def showhelp():    helpmsg = """ARP MODULE HELP (Press ENTER for more or CTRL-C to break)Constants:    Graphical representation of an ARP frame    FRAME_SAMPLE    Headers for crafting ARP / RARP packets    ARP_REQUEST, ARP_REPLY, RARP_REQUEST, RARP_REPLY    Other    ARP_LENGTH, RARP_LENGTH, DEFAULTFunctions:    find_device() - Returns an identifier to the first available network    interface.    open_device(device=DEFAULT) - Returns a handle to an available network    device.    close_device() - Close the previously opened handle.    send_raw(device, packet) - Send a raw ethernet frame. Returns    the number of bytes sent.    multisend_raw(device, packetlist=[], interval=0) - Send multiple packets    across a network at the specified interval. Returns the number of bytes    sent.    arp_resolve(destination, strformat=True, source=None) - Returns the mac    address associated with the ip specified by 'destination'. The destination    ip is supplied in dotted decimal string format. strformat parameter    specifies whether the return value is in a hexadecimal string format or    in list format (c_ulong*2) which can further be formatted using    the 'mac_straddr' function (see below). 'source' specifies the ip address    of the sender, also supplied in dotted decimal string format.    arp_reply(dest_ip, dest_mac, src_ip, src_mac) - Send gratuitous ARP    replies. This can be used for ARP spoofing if the parameters are chosen    correctly. dest_ip is the destination ip in either dotted decimal    string format or hexadecimal string format (returned by 'ip_straddr').    dest_mac is the destination mac address and must be in hexadecimal    string format. If 'arp_resolve' is used with strformat=True the return    value can be used directly. src_ip specifies the ip address of the    sender and src_mac the mac address of the sender.    rarp_reply(dest_ip, dest_mac, src_ip, src_mac) - Send gratuitous RARP    replies. Operates similar to 'arp_reply'.    mac_straddr(mac, printable=False, delimiter=None) - Convert a mac    address in list format (c_ulong*2) to normal hexadecimal string    format or printable format. Alternatively a delimiter can be specified    for printable formats, e.g ':' for ff:ff:ff:ff:ff:ff.    ip_straddr(ip, printable=False) - Convert an ip address in    dotted decimal string format to hexadecimal string format. Alternatively    this function can output a printable representation of the hex    string format."""    for line in helpmsg.split('\n'):        print line,        raw_input('')if __name__ == "__main__":    """ Test the module by sending an ARP query """    ip = "10.0.0.8"    result = arp_resolve(ip, 0)    print ip, "is at", mac_straddr(result, 1, ":")