275 lines
7.7 KiB
Python
275 lines
7.7 KiB
Python
"""Utilities for identifying local IP addresses."""
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# Copyright (c) Jupyter Development Team.
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# Distributed under the terms of the Modified BSD License.
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import os
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import re
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import socket
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import subprocess
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from subprocess import Popen, PIPE
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from warnings import warn
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LOCAL_IPS = []
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PUBLIC_IPS = []
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LOCALHOST = ''
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def _uniq_stable(elems):
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"""uniq_stable(elems) -> list
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Return from an iterable, a list of all the unique elements in the input,
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maintaining the order in which they first appear.
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From ipython_genutils.data
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"""
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seen = set()
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return [x for x in elems if x not in seen and not seen.add(x)]
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def _get_output(cmd):
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"""Get output of a command, raising IOError if it fails"""
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startupinfo = None
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if os.name == 'nt':
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startupinfo = subprocess.STARTUPINFO()
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startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW
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p = Popen(cmd, stdout=PIPE, stderr=PIPE, startupinfo=startupinfo)
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stdout, stderr = p.communicate()
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if p.returncode:
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raise IOError("Failed to run %s: %s" % (cmd, stderr.decode('utf8', 'replace')))
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return stdout.decode('utf8', 'replace')
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def _only_once(f):
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"""decorator to only run a function once"""
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f.called = False
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def wrapped(**kwargs):
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if f.called:
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return
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ret = f(**kwargs)
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f.called = True
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return ret
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return wrapped
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def _requires_ips(f):
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"""decorator to ensure load_ips has been run before f"""
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def ips_loaded(*args, **kwargs):
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_load_ips()
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return f(*args, **kwargs)
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return ips_loaded
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# subprocess-parsing ip finders
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class NoIPAddresses(Exception):
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pass
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def _populate_from_list(addrs):
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"""populate local and public IPs from flat list of all IPs"""
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if not addrs:
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raise NoIPAddresses
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global LOCALHOST
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public_ips = []
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local_ips = []
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for ip in addrs:
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local_ips.append(ip)
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if not ip.startswith('127.'):
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public_ips.append(ip)
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elif not LOCALHOST:
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LOCALHOST = ip
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if not LOCALHOST:
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LOCALHOST = '127.0.0.1'
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local_ips.insert(0, LOCALHOST)
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local_ips.extend(['0.0.0.0', ''])
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LOCAL_IPS[:] = _uniq_stable(local_ips)
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PUBLIC_IPS[:] = _uniq_stable(public_ips)
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_ifconfig_ipv4_pat = re.compile(r'inet\b.*?(\d+\.\d+\.\d+\.\d+)', re.IGNORECASE)
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def _load_ips_ifconfig():
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"""load ip addresses from `ifconfig` output (posix)"""
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try:
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out = _get_output('ifconfig')
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except (IOError, OSError):
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# no ifconfig, it's usually in /sbin and /sbin is not on everyone's PATH
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out = _get_output('/sbin/ifconfig')
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lines = out.splitlines()
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addrs = []
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for line in lines:
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m = _ifconfig_ipv4_pat.match(line.strip())
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if m:
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addrs.append(m.group(1))
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_populate_from_list(addrs)
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def _load_ips_ip():
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"""load ip addresses from `ip addr` output (Linux)"""
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out = _get_output(['ip', '-f', 'inet', 'addr'])
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lines = out.splitlines()
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addrs = []
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for line in lines:
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blocks = line.lower().split()
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if (len(blocks) >= 2) and (blocks[0] == 'inet'):
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addrs.append(blocks[1].split('/')[0])
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_populate_from_list(addrs)
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_ipconfig_ipv4_pat = re.compile(r'ipv4.*?(\d+\.\d+\.\d+\.\d+)$', re.IGNORECASE)
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def _load_ips_ipconfig():
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"""load ip addresses from `ipconfig` output (Windows)"""
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out = _get_output('ipconfig')
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lines = out.splitlines()
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addrs = []
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for line in lines:
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m = _ipconfig_ipv4_pat.match(line.strip())
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if m:
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addrs.append(m.group(1))
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_populate_from_list(addrs)
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def _load_ips_netifaces():
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"""load ip addresses with netifaces"""
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import netifaces
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global LOCALHOST
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local_ips = []
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public_ips = []
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# list of iface names, 'lo0', 'eth0', etc.
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for iface in netifaces.interfaces():
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# list of ipv4 addrinfo dicts
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ipv4s = netifaces.ifaddresses(iface).get(netifaces.AF_INET, [])
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for entry in ipv4s:
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addr = entry.get('addr')
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if not addr:
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continue
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if not (iface.startswith('lo') or addr.startswith('127.')):
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public_ips.append(addr)
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elif not LOCALHOST:
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LOCALHOST = addr
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local_ips.append(addr)
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if not LOCALHOST:
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# we never found a loopback interface (can this ever happen?), assume common default
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LOCALHOST = '127.0.0.1'
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local_ips.insert(0, LOCALHOST)
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local_ips.extend(['0.0.0.0', ''])
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LOCAL_IPS[:] = _uniq_stable(local_ips)
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PUBLIC_IPS[:] = _uniq_stable(public_ips)
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def _load_ips_gethostbyname():
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"""load ip addresses with socket.gethostbyname_ex
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This can be slow.
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"""
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global LOCALHOST
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try:
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LOCAL_IPS[:] = socket.gethostbyname_ex('localhost')[2]
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except socket.error:
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# assume common default
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LOCAL_IPS[:] = ['127.0.0.1']
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try:
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hostname = socket.gethostname()
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PUBLIC_IPS[:] = socket.gethostbyname_ex(hostname)[2]
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# try hostname.local, in case hostname has been short-circuited to loopback
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if not hostname.endswith('.local') and all(ip.startswith('127') for ip in PUBLIC_IPS):
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PUBLIC_IPS[:] = socket.gethostbyname_ex(socket.gethostname() + '.local')[2]
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except socket.error:
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pass
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finally:
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PUBLIC_IPS[:] = _uniq_stable(PUBLIC_IPS)
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LOCAL_IPS.extend(PUBLIC_IPS)
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# include all-interface aliases: 0.0.0.0 and ''
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LOCAL_IPS.extend(['0.0.0.0', ''])
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LOCAL_IPS[:] = _uniq_stable(LOCAL_IPS)
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LOCALHOST = LOCAL_IPS[0]
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def _load_ips_dumb():
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"""Fallback in case of unexpected failure"""
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global LOCALHOST
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LOCALHOST = '127.0.0.1'
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LOCAL_IPS[:] = [LOCALHOST, '0.0.0.0', '']
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PUBLIC_IPS[:] = []
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@_only_once
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def _load_ips(suppress_exceptions=True):
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"""load the IPs that point to this machine
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This function will only ever be called once.
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It will use netifaces to do it quickly if available.
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Then it will fallback on parsing the output of ifconfig / ip addr / ipconfig, as appropriate.
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Finally, it will fallback on socket.gethostbyname_ex, which can be slow.
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"""
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try:
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# first priority, use netifaces
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try:
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return _load_ips_netifaces()
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except ImportError:
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pass
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# second priority, parse subprocess output (how reliable is this?)
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if os.name == 'nt':
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try:
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return _load_ips_ipconfig()
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except (IOError, NoIPAddresses):
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pass
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else:
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try:
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return _load_ips_ip()
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except (IOError, OSError, NoIPAddresses):
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pass
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try:
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return _load_ips_ifconfig()
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except (IOError, OSError, NoIPAddresses):
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pass
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# lowest priority, use gethostbyname
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return _load_ips_gethostbyname()
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except Exception as e:
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if not suppress_exceptions:
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raise
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# unexpected error shouldn't crash, load dumb default values instead.
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warn("Unexpected error discovering local network interfaces: %s" % e)
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_load_ips_dumb()
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@_requires_ips
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def local_ips():
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"""return the IP addresses that point to this machine"""
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return LOCAL_IPS
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@_requires_ips
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def public_ips():
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"""return the IP addresses for this machine that are visible to other machines"""
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return PUBLIC_IPS
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@_requires_ips
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def localhost():
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"""return ip for localhost (almost always 127.0.0.1)"""
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return LOCALHOST
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@_requires_ips
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def is_local_ip(ip):
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"""does `ip` point to this machine?"""
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return ip in LOCAL_IPS
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@_requires_ips
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def is_public_ip(ip):
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"""is `ip` a publicly visible address?"""
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return ip in PUBLIC_IPS
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