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SocketPermission Class

Controls rights to make or accept connections on a transport address.

Namespace:  System.Net
Assembly:  System (in System.dll)

'Declaration
<SerializableAttribute> _
Public NotInheritable Class SocketPermission _
	Inherits CodeAccessPermission _
	Implements IUnrestrictedPermission
'Usage
Dim instance As SocketPermission

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.

NoteNote:

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 = 
    __try_cast<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->AcceptList;
    while (myEnumerator->MoveNext()) {
        Console::WriteLine(__try_cast<EndpointPermission *>(myEnumerator->Current)->ToString());
    }      

    // Prints the allowable connect URIs to the console.
    Console::WriteLine("This union permits connections to :");

    myEnumerator = mySocketPermissionUnion->ConnectList;
    while (myEnumerator->MoveNext()) {
        Console::WriteLine(__try_cast<EndpointPermission *>(myEnumerator->Current)->ToString());
    }      

}


// Creates a SocketPermission from the intersect of two SocketPermissions.
SocketPermission *mySocketPermissionIntersect = 
    __try_cast<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 = 
    __try_cast<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->AddressList[0], 11000);

Socket *s = new Socket(myLocalEndPoint->Address->AddressFamily,
    SocketType::Stream, ProtocolType::Tcp);
try{
    s->Connect(myLocalEndPoint);
}
catch (Exception *e){
    Console::Write("Exception Thrown: ");
    Console::WriteLine(e->ToString());
} 

// Perform all socket operations in here.

s->Close();

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0
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