1from __future__ import absolute_import 2 3import socket 4 5from urllib3.exceptions import LocationParseError 6 7from ..contrib import _appengine_environ 8from ..packages import six 9from .wait import NoWayToWaitForSocketError, wait_for_read 10 11 12def is_connection_dropped(conn): # Platform-specific 13 """ 14 Returns True if the connection is dropped and should be closed. 15 16 :param conn: 17 :class:`http.client.HTTPConnection` object. 18 19 Note: For platforms like AppEngine, this will always return ``False`` to 20 let the platform handle connection recycling transparently for us. 21 """ 22 sock = getattr(conn, "sock", False) 23 if sock is False: # Platform-specific: AppEngine 24 return False 25 if sock is None: # Connection already closed (such as by httplib). 26 return True 27 try: 28 # Returns True if readable, which here means it's been dropped 29 return wait_for_read(sock, timeout=0.0) 30 except NoWayToWaitForSocketError: # Platform-specific: AppEngine 31 return False 32 33 34# This function is copied from socket.py in the Python 2.7 standard 35# library test suite. Added to its signature is only `socket_options`. 36# One additional modification is that we avoid binding to IPv6 servers 37# discovered in DNS if the system doesn't have IPv6 functionality. 38def create_connection( 39 address, 40 timeout=socket._GLOBAL_DEFAULT_TIMEOUT, 41 source_address=None, 42 socket_options=None, 43): 44 """Connect to *address* and return the socket object. 45 46 Convenience function. Connect to *address* (a 2-tuple ``(host, 47 port)``) and return the socket object. Passing the optional 48 *timeout* parameter will set the timeout on the socket instance 49 before attempting to connect. If no *timeout* is supplied, the 50 global default timeout setting returned by :func:`socket.getdefaulttimeout` 51 is used. If *source_address* is set it must be a tuple of (host, port) 52 for the socket to bind as a source address before making the connection. 53 An host of '' or port 0 tells the OS to use the default. 54 """ 55 56 host, port = address 57 if host.startswith("["): 58 host = host.strip("[]") 59 err = None 60 61 # Using the value from allowed_gai_family() in the context of getaddrinfo lets 62 # us select whether to work with IPv4 DNS records, IPv6 records, or both. 63 # The original create_connection function always returns all records. 64 family = allowed_gai_family() 65 66 try: 67 host.encode("idna") 68 except UnicodeError: 69 return six.raise_from( 70 LocationParseError(u"'%s', label empty or too long" % host), None 71 ) 72 73 for res in socket.getaddrinfo(host, port, family, socket.SOCK_STREAM): 74 af, socktype, proto, canonname, sa = res 75 sock = None 76 try: 77 sock = socket.socket(af, socktype, proto) 78 79 # If provided, set socket level options before connecting. 80 _set_socket_options(sock, socket_options) 81 82 if timeout is not socket._GLOBAL_DEFAULT_TIMEOUT: 83 sock.settimeout(timeout) 84 if source_address: 85 sock.bind(source_address) 86 sock.connect(sa) 87 return sock 88 89 except socket.error as e: 90 err = e 91 if sock is not None: 92 sock.close() 93 sock = None 94 95 if err is not None: 96 raise err 97 98 raise socket.error("getaddrinfo returns an empty list") 99 100 101def _set_socket_options(sock, options): 102 if options is None: 103 return 104 105 for opt in options: 106 sock.setsockopt(*opt) 107 108 109def allowed_gai_family(): 110 """This function is designed to work in the context of 111 getaddrinfo, where family=socket.AF_UNSPEC is the default and 112 will perform a DNS search for both IPv6 and IPv4 records.""" 113 114 family = socket.AF_INET 115 if HAS_IPV6: 116 family = socket.AF_UNSPEC 117 return family 118 119 120def _has_ipv6(host): 121 """Returns True if the system can bind an IPv6 address.""" 122 sock = None 123 has_ipv6 = False 124 125 # App Engine doesn't support IPV6 sockets and actually has a quota on the 126 # number of sockets that can be used, so just early out here instead of 127 # creating a socket needlessly. 128 # See https://github.com/urllib3/urllib3/issues/1446 129 if _appengine_environ.is_appengine_sandbox(): 130 return False 131 132 if socket.has_ipv6: 133 # has_ipv6 returns true if cPython was compiled with IPv6 support. 134 # It does not tell us if the system has IPv6 support enabled. To 135 # determine that we must bind to an IPv6 address. 136 # https://github.com/urllib3/urllib3/pull/611 137 # https://bugs.python.org/issue658327 138 try: 139 sock = socket.socket(socket.AF_INET6) 140 sock.bind((host, 0)) 141 has_ipv6 = True 142 except Exception: 143 pass 144 145 if sock: 146 sock.close() 147 return has_ipv6 148 149 150HAS_IPV6 = _has_ipv6("::1") 151