Understanding the Active Directory RPC APIs

Before SDS.AD, Active Directory programmers were forced into different camps based on the programming language they used. The original design of the directory services APIs had some features of Active Directory available via LDAP, and others were available only by RPC calls. The LDAP features were (for the most part) available to the higher-level languages because they could use ADSI with the LDAP provider. However, the RPC calls were designed for C++ users only. While some of these APIs got explicit ADSI wrappers (for example, DsCrackNames and IADsNameTranslate), many did not.

As such, the high-level languages were second-class citizens. This tradition continued with .NET Framework version 1.x, as SDS really just wrapped ADSI functionality. While we had the ability to access the other APIs via P/Invoke, they were not packaged neatly for us.

The key design challenge for the SDS.AD namespace was to find a way to marry the LDAP and RPC functionality together into a cohesive design. In our opinion, this design is quite successful and is leaps and bounds better than what we had before or what we would likely have cobbled together on our own with a bunch of P/Invoke statements.

The purpose of this section is to briefly overview some of the other Active Directory RPC APIs to get a better feel for what they do. Table 9.1 breaks down most of them and categorizes them by use. We also show which ones SDS.AD uses directly.

Table 9.1. Active Directory RPC API Functions

Purpose

RPC function

Wrapped in SDS.AD

These APIs are used to access the Locator services. With them, we can find the current domain, forest, global catalog servers, and all domain controllers. All of these methods allow anonymous credentials.

DsGetDcName

Yes

DsGetDcOpen

Yes

DsGetDcNext

Yes

DsGetSiteName

No

DsGetDcSiteCoverage

No

DsGetDcClose

Yes

NetApiBufferFree

Yes

In order to use a number of the other Ds* APIs, we must have a handle to an RPC session with a domain controller. These APIs are used to bind to the directory and obtain the handle necessary for further Ds* API calls.

DsBind

No

DsBindWithCred

Yes

DsBindWithSpn

No

DsBindWithSpnEx

No

DsMakePasswordCredentials

Yes

DsUnBind

Yes

DsFreePasswordCredentials

Yes

Once we have an established RPC session, we can use the handle we obtained to query for more information or to use utility functions. These methods use an authenticated session and return information that would be difficult to obtain without fairly complicated directory searches.

DsGetDomainControllerInfo

Yes

DsListDomainsInSite

Yes

DsListInfoForServer

No

DsListRoles

Yes

DsListSites

Yes

DsListServersInSite

No

DsListServersForDomainInSite

No

DsCrackNames

Yes

DsFreeDomainControllerInfo

Yes

DsFreeNameResult

Yes

As Table 9.1 shows, SDS.AD uses quite a few of these API calls. We would need to wrap each method ourselves in order to achieve similar functionality. Since we know that this is a lot of work, we have created wrappers for a number of the methods listed in Table 9.1 for you and we included them on this book's web site for download.

Useful Shortcuts for Developers

Part I: Fundamentals

Introduction to LDAP and Active Directory

Introduction to .NET Directory Services Programming

Binding and CRUD Operations with DirectoryEntry

Searching with the DirectorySearcher

Advanced LDAP Searches

Reading and Writing LDAP Attributes

Active Directory and ADAM Schema

Security in Directory Services Programming

Introduction to the ActiveDirectory Namespace

Part II: Practical Applications

User Management

Group Management

Authentication

Part III: Appendixes

Appendix A. Three Approaches to COM Interop with ADSI

Appendix B. LDAP Tools for Programmers

Appendix C. Troubleshooting and Help

Index





The. NET Developer's Guide to Directory Services Programming
The .NET Developers Guide to Directory Services Programming
ISBN: 0321350170
EAN: 2147483647
Year: 2004
Pages: 165
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