86890704fd
todo: add documentation & wireshark dissector
355 lines
12 KiB
Python
Executable file
355 lines
12 KiB
Python
Executable file
# This file is part of Scapy
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# See http://www.secdev.org/projects/scapy for more information
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# Copyright (C) Philippe Biondi <phil@secdev.org>
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# This program is published under a GPLv2 license
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"""
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Common customizations for all Unix-like operating systems other than Linux
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"""
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import os
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import socket
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import scapy.config
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import scapy.utils
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from scapy.arch import get_if_addr
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from scapy.config import conf
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from scapy.consts import FREEBSD, NETBSD, OPENBSD, SOLARIS
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from scapy.error import warning, log_interactive
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from scapy.pton_ntop import inet_pton
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from scapy.utils6 import in6_getscope, construct_source_candidate_set
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from scapy.utils6 import in6_isvalid, in6_ismlladdr, in6_ismnladdr
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##################
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# Routes stuff #
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##################
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def _guess_iface_name(netif):
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"""
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We attempt to guess the name of interfaces that are truncated from the
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output of ifconfig -l.
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If there is only one possible candidate matching the interface name then we
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return it.
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If there are none or more, then we return None.
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"""
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with os.popen('%s -l' % conf.prog.ifconfig) as fdesc:
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ifaces = fdesc.readline().strip().split(' ')
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matches = [iface for iface in ifaces if iface.startswith(netif)]
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if len(matches) == 1:
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return matches[0]
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return None
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def read_routes():
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"""Return a list of IPv4 routes than can be used by Scapy.
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This function parses netstat.
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"""
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if SOLARIS:
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f = os.popen("netstat -rvn -f inet")
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elif FREEBSD:
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f = os.popen("netstat -rnW") # -W to handle long interface names
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else:
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f = os.popen("netstat -rn -f inet")
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ok = 0
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mtu_present = False
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prio_present = False
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refs_present = False
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use_present = False
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routes = []
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pending_if = []
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for line in f.readlines():
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if not line:
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break
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line = line.strip().lower()
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if line.find("----") >= 0: # a separation line
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continue
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if not ok:
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if line.find("destination") >= 0:
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ok = 1
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mtu_present = "mtu" in line
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prio_present = "prio" in line
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refs_present = "ref" in line # There is no s on Solaris
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use_present = "use" in line
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continue
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if not line:
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break
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rt = line.split()
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if SOLARIS:
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dest, netmask, gw, netif = rt[:4]
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flg = rt[4 + mtu_present + refs_present]
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else:
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dest, gw, flg = rt[:3]
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locked = OPENBSD and rt[6] == "l"
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offset = mtu_present + prio_present + refs_present + locked
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offset += use_present
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netif = rt[3 + offset]
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if flg.find("lc") >= 0:
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continue
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elif dest == "default":
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dest = 0
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netmask = 0
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elif SOLARIS:
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dest = scapy.utils.atol(dest)
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netmask = scapy.utils.atol(netmask)
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else:
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if "/" in dest:
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dest, netmask = dest.split("/")
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netmask = scapy.utils.itom(int(netmask))
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else:
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netmask = scapy.utils.itom((dest.count(".") + 1) * 8)
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dest += ".0" * (3 - dest.count("."))
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dest = scapy.utils.atol(dest)
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# XXX: TODO: add metrics for unix.py (use -e option on netstat)
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metric = 1
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if "g" not in flg:
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gw = '0.0.0.0'
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if netif is not None:
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try:
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ifaddr = get_if_addr(netif)
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routes.append((dest, netmask, gw, netif, ifaddr, metric))
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except OSError as exc:
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if exc.message == 'Device not configured':
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# This means the interface name is probably truncated by
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# netstat -nr. We attempt to guess it's name and if not we
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# ignore it.
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guessed_netif = _guess_iface_name(netif)
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if guessed_netif is not None:
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ifaddr = get_if_addr(guessed_netif)
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routes.append((dest, netmask, gw, guessed_netif, ifaddr, metric)) # noqa: E501
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else:
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warning("Could not guess partial interface name: %s", netif) # noqa: E501
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else:
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raise
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else:
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pending_if.append((dest, netmask, gw))
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f.close()
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# On Solaris, netstat does not provide output interfaces for some routes
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# We need to parse completely the routing table to route their gw and
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# know their output interface
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for dest, netmask, gw in pending_if:
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gw_l = scapy.utils.atol(gw)
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max_rtmask, gw_if, gw_if_addr, = 0, None, None
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for rtdst, rtmask, _, rtif, rtaddr in routes[:]:
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if gw_l & rtmask == rtdst:
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if rtmask >= max_rtmask:
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max_rtmask = rtmask
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gw_if = rtif
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gw_if_addr = rtaddr
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# XXX: TODO add metrics
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metric = 1
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if gw_if:
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routes.append((dest, netmask, gw, gw_if, gw_if_addr, metric))
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else:
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warning("Did not find output interface to reach gateway %s", gw)
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return routes
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############
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# IPv6 #
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############
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def _in6_getifaddr(ifname):
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"""
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Returns a list of IPv6 addresses configured on the interface ifname.
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"""
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# Get the output of ifconfig
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try:
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f = os.popen("%s %s" % (conf.prog.ifconfig, ifname))
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except OSError:
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log_interactive.warning("Failed to execute ifconfig.")
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return []
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# Iterate over lines and extract IPv6 addresses
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ret = []
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for line in f:
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if "inet6" in line:
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addr = line.rstrip().split(None, 2)[1] # The second element is the IPv6 address # noqa: E501
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else:
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continue
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if '%' in line: # Remove the interface identifier if present
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addr = addr.split("%", 1)[0]
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# Check if it is a valid IPv6 address
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try:
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inet_pton(socket.AF_INET6, addr)
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except (socket.error, ValueError):
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continue
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# Get the scope and keep the address
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scope = in6_getscope(addr)
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ret.append((addr, scope, ifname))
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f.close()
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return ret
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def in6_getifaddr():
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"""
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Returns a list of 3-tuples of the form (addr, scope, iface) where
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'addr' is the address of scope 'scope' associated to the interface
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'iface'.
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This is the list of all addresses of all interfaces available on
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the system.
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"""
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# List all network interfaces
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if OPENBSD or SOLARIS:
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if SOLARIS:
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cmd = "%s -a6"
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else:
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cmd = "%s"
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try:
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f = os.popen(cmd % conf.prog.ifconfig)
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except OSError:
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log_interactive.warning("Failed to execute ifconfig.")
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return []
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# Get the list of network interfaces
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splitted_line = []
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for l in f:
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if "flags" in l:
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iface = l.split()[0].rstrip(':')
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splitted_line.append(iface)
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else: # FreeBSD, NetBSD or Darwin
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try:
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f = os.popen("%s -l" % conf.prog.ifconfig)
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except OSError:
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log_interactive.warning("Failed to execute ifconfig.")
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return []
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# Get the list of network interfaces
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splitted_line = f.readline().rstrip().split()
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ret = []
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for i in splitted_line:
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ret += _in6_getifaddr(i)
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f.close()
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return ret
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def read_routes6():
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"""Return a list of IPv6 routes than can be used by Scapy.
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This function parses netstat.
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"""
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# Call netstat to retrieve IPv6 routes
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fd_netstat = os.popen("netstat -rn -f inet6")
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# List interfaces IPv6 addresses
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lifaddr = in6_getifaddr()
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if not lifaddr:
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fd_netstat.close()
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return []
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# Routes header information
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got_header = False
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mtu_present = False
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prio_present = False
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# Parse the routes
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routes = []
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for line in fd_netstat.readlines():
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# Parse the routes header and try to identify extra columns
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if not got_header:
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if "Destination" == line[:11]:
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got_header = True
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mtu_present = "Mtu" in line
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prio_present = "Prio" in line
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continue
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# Parse a route entry according to the operating system
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splitted_line = line.split()
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if OPENBSD or NETBSD:
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index = 5 + mtu_present + prio_present
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if len(splitted_line) < index:
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warning("Not enough columns in route entry !")
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continue
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destination, next_hop, flags = splitted_line[:3]
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dev = splitted_line[index]
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else:
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# FREEBSD or DARWIN
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if len(splitted_line) < 4:
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warning("Not enough columns in route entry !")
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continue
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destination, next_hop, flags, dev = splitted_line[:4]
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# XXX: TODO: add metrics for unix.py (use -e option on netstat)
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metric = 1
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# Check flags
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if "U" not in flags: # usable route
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continue
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if "R" in flags: # Host or net unreachable
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continue
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if "m" in flags: # multicast address
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# Note: multicast routing is handled in Route6.route()
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continue
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# Replace link with the default route in next_hop
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if "link" in next_hop:
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next_hop = "::"
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# Default prefix length
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destination_plen = 128
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# Extract network interface from the zone id
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if '%' in destination:
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destination, dev = destination.split('%')
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if '/' in dev:
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# Example: fe80::%lo0/64 ; dev = "lo0/64"
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dev, destination_plen = dev.split('/')
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if '%' in next_hop:
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next_hop, dev = next_hop.split('%')
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# Ensure that the next hop is a valid IPv6 address
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if not in6_isvalid(next_hop):
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# Note: the 'Gateway' column might contain a MAC address
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next_hop = "::"
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# Modify parsed routing entries
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# Note: these rules are OS specific and may evolve over time
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if destination == "default":
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destination, destination_plen = "::", 0
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elif '/' in destination:
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# Example: fe80::/10
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destination, destination_plen = destination.split('/')
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if '/' in dev:
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# Example: ff02::%lo0/32 ; dev = "lo0/32"
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dev, destination_plen = dev.split('/')
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# Check route entries parameters consistency
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if not in6_isvalid(destination):
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warning("Invalid destination IPv6 address in route entry !")
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continue
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try:
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destination_plen = int(destination_plen)
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except Exception:
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warning("Invalid IPv6 prefix length in route entry !")
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continue
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if in6_ismlladdr(destination) or in6_ismnladdr(destination):
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# Note: multicast routing is handled in Route6.route()
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continue
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if conf.loopback_name in dev:
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# Handle ::1 separately
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cset = ["::1"]
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next_hop = "::"
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else:
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# Get possible IPv6 source addresses
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devaddrs = (x for x in lifaddr if x[2] == dev)
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cset = construct_source_candidate_set(destination, destination_plen, devaddrs) # noqa: E501
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if len(cset):
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routes.append((destination, destination_plen, next_hop, dev, cset, metric)) # noqa: E501
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fd_netstat.close()
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return routes
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