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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")