我想做这样的事情：

            10.1.1.0/24          10.1.2.0/24

+------------+       +------------+       +------------+
|            |       |            |       |            |
|            |       |            |       |            |
|     A    d +-------+ e   B    f +-------+ g   C      |
|            |       |            |       |            |
|            |       |            |       |            |
+------------+       +------------+       +------------+

    d              e           f           g
    10.1.1.1       10.1.1.2    10.1.2.1    10.1.2.2

这样A可以将数据包发送到C通过B。

我尝试通过在端口和上嗅探一个Scapy程序来构建此东西，然后分别修改数据包中的目标IP和MAC地址，然后通过另一个接口将其发送。就像是：B``e``f

my_macs = [get_if_hwaddr(i) for i in get_if_list()]
pktcnt = 0
dest_mac_address = discover_mac_for_ip(dest_ip) # 
output_mac = get_if_hwaddr(output_interface)

def process_packet(pkt):
    # ignore packets that were sent from one of our own interfaces
    if pkt[Ether].src in my_macs:
        return

    pktcnt += 1
    p = pkt.copy()
    # if this packet has an IP layer, change the dst field
    # to our final destination
    if IP in p:
        p[IP].dst = dest_ip

    # if this packet has an ethernet layer, change the dst field
    # to our final destination. We have to worry about this since
    # we're using sendp (rather than send) to send the packet.  We
    # also don't fiddle with it if it's a broadcast address.
    if Ether in p \
       and p[Ether].dst != 'ff:ff:ff:ff:ff:ff':
        p[Ether].dst = dest_mac_address
        p[Ether].src = output_mac

    # use sendp to avoid ARP'ing and stuff
    sendp(p, iface=output_interface)

sniff(iface=input_interface, prn=process_packet)

但是，当我运行该程序时（这里有完整的源代码），各种疯狂的事情开始发生……某些数据包通过了，甚至得到了一些响应（使用进行测试ping），但是有某种类型的反馈循环导致一堆重复的数据包被发送…

有什么想法吗？尝试这样做疯狂吗？

我有点怀疑反馈循环是由B对数据包自己进行一些处理的事实引起的。有什么方法可以防止操作系统在嗅探数据包后对其进行处理？