SocketPermission Class
Assembly: System (in system.dll)
'Declaration <SerializableAttribute> _ Public NotInheritable Class SocketPermission Inherits CodeAccessPermission Implements IUnrestrictedPermission 'Usage Dim instance As SocketPermission
/** @attribute SerializableAttribute() */ public final class SocketPermission extends CodeAccessPermission implements IUnrestrictedPermission
SerializableAttribute public final class SocketPermission extends CodeAccessPermission implements IUnrestrictedPermission
SocketPermission instances control permission to accept connections or initiate Socket connections. A Socket permission can be established for a host name or IP address, a port number, and a transport protocol.
Note |
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| Avoid creating socket permissions using host names, as these names have to be resolved to IP addresses, and this might block the stack. |
The following example demonstrates how to use the SocketPermission class to set, change, and enforce various socket access restrictions.
' Creates a SocketPermission restricting access to and from all URIs. Dim mySocketPermission1 As New SocketPermission(PermissionState.None) ' The socket to which this permission will apply will allow connections from www.contoso.com. mySocketPermission1.AddPermission(NetworkAccess.Accept, TransportType.Tcp, "www.contoso.com", 11000) ' Creates a SocketPermission which will allow the target Socket to connect with www.southridgevideo.com. Dim mySocketPermission2 As New SocketPermission(NetworkAccess.Connect, TransportType.Tcp, "www.southridgevideo.com", 11002) ' Creates a SocketPermission from the union of two SocketPermissions. Dim mySocketPermissionUnion As SocketPermission = CType(mySocketPermission1.Union(mySocketPermission2), SocketPermission) ' Checks to see if the union was successfully created by using the IsSubsetOf method. If mySocketPermission1.IsSubsetOf(mySocketPermissionUnion) And mySocketPermission2.IsSubsetOf(mySocketPermissionUnion) Then Console.WriteLine("This union contains permissions from both mySocketPermission1 and mySocketPermission2") ' Prints the allowable accept URIs to the console. Console.WriteLine("This union accepts connections on :") Dim myEnumerator As IEnumerator = mySocketPermissionUnion.AcceptList While myEnumerator.MoveNext() Console.WriteLine(CType(myEnumerator.Current, EndpointPermission).ToString()) End While Console.WriteLine("This union establishes connections on : ") ' Prints the allowable connect URIs to the console. Console.WriteLine("This union permits connections to :") myEnumerator = mySocketPermissionUnion.ConnectList While myEnumerator.MoveNext() Console.WriteLine(CType(myEnumerator.Current, EndpointPermission).ToString()) End While End If ' Creates a SocketPermission from the intersect of two SocketPermissions. Dim mySocketPermissionIntersect As SocketPermission = CType(mySocketPermission1.Intersect(mySocketPermissionUnion), SocketPermission) ' mySocketPermissionIntersect should now contain the permissions of mySocketPermission1. If mySocketPermission1.IsSubsetOf(mySocketPermissionIntersect) Then Console.WriteLine("This is expected") End If ' mySocketPermissionIntersect should not contain the permissios of mySocketPermission2. If mySocketPermission2.IsSubsetOf(mySocketPermissionIntersect) Then Console.WriteLine("This should not print") End If ' Creates a copy of the intersect SocketPermission. Dim mySocketPermissionIntersectCopy As SocketPermission = CType(mySocketPermissionIntersect.Copy(), SocketPermission) If mySocketPermissionIntersectCopy.Equals(mySocketPermissionIntersect) Then Console.WriteLine("Copy successfull") End If ' Converts a SocketPermission to XML format and then immediately converts it back to a SocketPermission. mySocketPermission1.FromXml(mySocketPermission1.ToXml()) ' Checks to see if permission for this socket resource is unrestricted. If it is, then there is no need to ' demand that permissions be enforced. If mySocketPermissionUnion.IsUnrestricted() Then 'Do nothing. There are no restrictions. Else ' Enforces the permissions found in mySocketPermissionUnion on any Socket Resources used below this statement. mySocketPermissionUnion.Demand() End If Dim myIpHostEntry As IPHostEntry = Dns.Resolve("www.contoso.com") Dim myLocalEndPoint As New IPEndPoint(myIpHostEntry.AddressList(0), 11000) Dim s As New Socket(myLocalEndPoint.Address.AddressFamily, SocketType.Stream, ProtocolType.Tcp) Try s.Connect(myLocalEndPoint) Catch e As Exception Console.WriteLine(("Exception Thrown: " + e.ToString())) End Try ' Perform all socket operations in here. s.Close() End Sub 'MySocketPermission
// Creates a SocketPermission restricting access to and from all URIs.
SocketPermission mySocketPermission1
= new SocketPermission(PermissionState.None);
// The socket to which this permission will apply will allow
// connections from www.contoso.com.
mySocketPermission1.AddPermission(NetworkAccess.Accept,
TransportType.Tcp, "www.contoso.com", 11000);
// Creates a SocketPermission which will allow the target Socket to
// connect with www.southridgevideo.com.
SocketPermission mySocketPermission2
= new SocketPermission(NetworkAccess.Connect,
TransportType.Tcp, "www.southridgevideo.com", 11002);
// Creates a SocketPermission from the union of two SocketPermissions.
SocketPermission mySocketPermissionUnion
= (SocketPermission)mySocketPermission1.Union(mySocketPermission2);
// Checks to see if the union was successfully created by using the
// IsSubsetOf method.
if (mySocketPermission1.IsSubsetOf(mySocketPermissionUnion)
&& mySocketPermission2.IsSubsetOf(mySocketPermissionUnion)) {
Console.WriteLine("This union contains permissions from both " + "mySocketPermission1 and mySocketPermission2");
// Prints the allowable accept URIs to the console.
Console.WriteLine("This union accepts connections on :");
IEnumerator myEnumerator = mySocketPermissionUnion.
get_AcceptList();
while (myEnumerator.MoveNext()) {
Console.WriteLine(((EndpointPermission)myEnumerator.
get_Current()).ToString());
}
// Prints the allowable connect URIs to the console.
Console.WriteLine("This union permits connections to :");
myEnumerator = mySocketPermissionUnion.get_ConnectList();
while (myEnumerator.MoveNext()) {
Console.WriteLine(((EndpointPermission)myEnumerator.
get_Current()).ToString());
}
}
// Creates a SocketPermission from the intersect of two
// SocketPermissions.
SocketPermission mySocketPermissionIntersect
= (SocketPermission)mySocketPermission1.
Intersect(mySocketPermissionUnion);
// mySocketPermissionIntersect should now contain the permissions of // mySocketPermission1.
if (mySocketPermission1.IsSubsetOf(mySocketPermissionIntersect)) {
Console.WriteLine("This is expected");
}
// mySocketPermissionIntersect should not contain the permissios of // mySocketPermission2.
if (mySocketPermission2.IsSubsetOf(mySocketPermissionIntersect)) {
Console.WriteLine("This should not print");
}
// Creates a copy of the intersect SocketPermission.
SocketPermission mySocketPermissionIntersectCopy
= (SocketPermission)mySocketPermissionIntersect.Copy();
if (mySocketPermissionIntersectCopy.
Equals(mySocketPermissionIntersect)) {
Console.WriteLine("Copy successfull");
}
// Converts a SocketPermission to XML format and then immediately
// converts it back to a SocketPermission.
mySocketPermission1.FromXml(mySocketPermission1.ToXml());
// Checks to see if permission for this socket resource is
// unrestricted. If it is, then there is no need to
// demand that permissions be enforced.
if (mySocketPermissionUnion.IsUnrestricted()) {
//Do nothing. There are no restrictions.
}
else {
// Enforces the permissions found in mySocketPermissionUnion on
// any Socket Resources used below this statement.
mySocketPermissionUnion.Demand();
}
IPHostEntry myIpHostEntry = Dns.Resolve("www.contoso.com");
IPEndPoint myLocalEndPoint = new IPEndPoint(myIpHostEntry.
get_AddressList()[0], 11000);
Socket s = new Socket(myLocalEndPoint.get_Address().
get_AddressFamily(), SocketType.Stream, ProtocolType.Tcp);
try {
s.Connect(myLocalEndPoint);
}
catch (System.Exception e) {
Console.WriteLine("Exception Thrown: " + e.ToString());
}
// Perform all socket operations in here.
s.Close();
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
Note