Open Media Library Platform

Darwin/lib/python2.7/site-packages/twisted/protocols/ident.py

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+# -*- test-case-name: twisted.test.test_ident -*-
+# Copyright (c) Twisted Matrix Laboratories.
+# See LICENSE for details.
+
+"""
+Ident protocol implementation.
+"""
+
+import struct
+
+from twisted.internet import defer
+from twisted.protocols import basic
+from twisted.python import log, failure
+
+_MIN_PORT = 1
+_MAX_PORT = 2 ** 16 - 1
+
+class IdentError(Exception):
+    """
+    Can't determine connection owner; reason unknown.
+    """
+
+    identDescription = 'UNKNOWN-ERROR'
+
+    def __str__(self):
+        return self.identDescription
+
+
+class NoUser(IdentError):
+    """
+    The connection specified by the port pair is not currently in use or
+    currently not owned by an identifiable entity.
+    """
+    identDescription = 'NO-USER'
+
+
+class InvalidPort(IdentError):
+    """
+    Either the local or foreign port was improperly specified. This should
+    be returned if either or both of the port ids were out of range (TCP
+    port numbers are from 1-65535), negative integers, reals or in any
+    fashion not recognized as a non-negative integer.
+    """
+    identDescription = 'INVALID-PORT'
+
+
+class HiddenUser(IdentError):
+    """
+    The server was able to identify the user of this port, but the
+    information was not returned at the request of the user.
+    """
+    identDescription = 'HIDDEN-USER'
+
+
+class IdentServer(basic.LineOnlyReceiver):
+    """
+    The Identification Protocol (a.k.a., "ident", a.k.a., "the Ident
+    Protocol") provides a means to determine the identity of a user of a
+    particular TCP connection. Given a TCP port number pair, it returns a
+    character string which identifies the owner of that connection on the
+    server's system.
+
+    Server authors should subclass this class and override the lookup method.
+    The default implementation returns an UNKNOWN-ERROR response for every
+    query.
+    """
+
+    def lineReceived(self, line):
+        parts = line.split(',')
+        if len(parts) != 2:
+            self.invalidQuery()
+        else:
+            try:
+                portOnServer, portOnClient = map(int, parts)
+            except ValueError:
+                self.invalidQuery()
+            else:
+                if _MIN_PORT <= portOnServer <= _MAX_PORT and _MIN_PORT <= portOnClient <= _MAX_PORT:
+                    self.validQuery(portOnServer, portOnClient)
+                else:
+                    self._ebLookup(failure.Failure(InvalidPort()), portOnServer, portOnClient)
+
+    def invalidQuery(self):
+        self.transport.loseConnection()
+
+
+    def validQuery(self, portOnServer, portOnClient):
+        """
+        Called when a valid query is received to look up and deliver the
+        response.
+
+        @param portOnServer: The server port from the query.
+        @param portOnClient: The client port from the query.
+        """
+        serverAddr = self.transport.getHost().host, portOnServer
+        clientAddr = self.transport.getPeer().host, portOnClient
+        defer.maybeDeferred(self.lookup, serverAddr, clientAddr
+            ).addCallback(self._cbLookup, portOnServer, portOnClient
+            ).addErrback(self._ebLookup, portOnServer, portOnClient
+            )
+
+
+    def _cbLookup(self, (sysName, userId), sport, cport):
+        self.sendLine('%d, %d : USERID : %s : %s' % (sport, cport, sysName, userId))
+
+    def _ebLookup(self, failure, sport, cport):
+        if failure.check(IdentError):
+            self.sendLine('%d, %d : ERROR : %s' % (sport, cport, failure.value))
+        else:
+            log.err(failure)
+            self.sendLine('%d, %d : ERROR : %s' % (sport, cport, IdentError(failure.value)))
+
+    def lookup(self, serverAddress, clientAddress):
+        """Lookup user information about the specified address pair.
+
+        Return value should be a two-tuple of system name and username.
+        Acceptable values for the system name may be found online at::
+
+            U{http://www.iana.org/assignments/operating-system-names}
+
+        This method may also raise any IdentError subclass (or IdentError
+        itself) to indicate user information will not be provided for the
+        given query.
+
+        A Deferred may also be returned.
+
+        @param serverAddress: A two-tuple representing the server endpoint
+        of the address being queried.  The first element is a string holding
+        a dotted-quad IP address.  The second element is an integer
+        representing the port.
+
+        @param clientAddress: Like L{serverAddress}, but represents the
+        client endpoint of the address being queried.
+        """
+        raise IdentError()
+
+class ProcServerMixin:
+    """Implements lookup() to grab entries for responses from /proc/net/tcp
+    """
+
+    SYSTEM_NAME = 'LINUX'
+
+    try:
+        from pwd import getpwuid
+        def getUsername(self, uid, getpwuid=getpwuid):
+            return getpwuid(uid)[0]
+        del getpwuid
+    except ImportError:
+        def getUsername(self, uid):
+            raise IdentError()
+
+    def entries(self):
+        f = file('/proc/net/tcp')
+        f.readline()
+        for L in f:
+            yield L.strip()
+
+    def dottedQuadFromHexString(self, hexstr):
+        return '.'.join(map(str, struct.unpack('4B', struct.pack('=L', int(hexstr, 16)))))
+
+    def unpackAddress(self, packed):
+        addr, port = packed.split(':')
+        addr = self.dottedQuadFromHexString(addr)
+        port = int(port, 16)
+        return addr, port
+
+    def parseLine(self, line):
+        parts = line.strip().split()
+        localAddr, localPort = self.unpackAddress(parts[1])
+        remoteAddr, remotePort = self.unpackAddress(parts[2])
+        uid = int(parts[7])
+        return (localAddr, localPort), (remoteAddr, remotePort), uid
+
+    def lookup(self, serverAddress, clientAddress):
+        for ent in self.entries():
+            localAddr, remoteAddr, uid = self.parseLine(ent)
+            if remoteAddr == clientAddress and localAddr[1] == serverAddress[1]:
+                return (self.SYSTEM_NAME, self.getUsername(uid))
+
+        raise NoUser()
+
+
+class IdentClient(basic.LineOnlyReceiver):
+
+    errorTypes = (IdentError, NoUser, InvalidPort, HiddenUser)
+
+    def __init__(self):
+        self.queries = []
+
+    def lookup(self, portOnServer, portOnClient):
+        """Lookup user information about the specified address pair.
+        """
+        self.queries.append((defer.Deferred(), portOnServer, portOnClient))
+        if len(self.queries) > 1:
+            return self.queries[-1][0]
+
+        self.sendLine('%d, %d' % (portOnServer, portOnClient))
+        return self.queries[-1][0]
+
+    def lineReceived(self, line):
+        if not self.queries:
+            log.msg("Unexpected server response: %r" % (line,))
+        else:
+            d, _, _ = self.queries.pop(0)
+            self.parseResponse(d, line)
+            if self.queries:
+                self.sendLine('%d, %d' % (self.queries[0][1], self.queries[0][2]))
+
+    def connectionLost(self, reason):
+        for q in self.queries:
+            q[0].errback(IdentError(reason))
+        self.queries = []
+
+    def parseResponse(self, deferred, line):
+        parts = line.split(':', 2)
+        if len(parts) != 3:
+            deferred.errback(IdentError(line))
+        else:
+            ports, type, addInfo = map(str.strip, parts)
+            if type == 'ERROR':
+                for et in self.errorTypes:
+                    if et.identDescription == addInfo:
+                        deferred.errback(et(line))
+                        return
+                deferred.errback(IdentError(line))
+            else:
+                deferred.callback((type, addInfo))
+
+__all__ = ['IdentError', 'NoUser', 'InvalidPort', 'HiddenUser',
+           'IdentServer', 'IdentClient',
+           'ProcServerMixin']