/*++

Copyright (c) 1995-1996  Microsoft Corporation

Module Name:

    httpfilt.h

Abstract:

    This module contains the Microsoft HTTP filter extension info

Revision History:

--*/

#ifndef _HTTPFILT_H_
#define _HTTPFILT_H_

#ifdef __cplusplus
extern "C" {
#endif

//
//  Current version of the filter spec is 2.0
//

#define HTTP_FILTER_REVISION    MAKELONG( 0, 2);

#define SF_MAX_USERNAME         (256+1)
#define SF_MAX_PASSWORD         (256+1)

#define SF_MAX_FILTER_DESC_LEN  (256+1)

//
//  These values can be used with the pfnSFCallback function supplied in
//  the filter context structure
//

enum SF_REQ_TYPE
{
    //
    //  Sends a complete HTTP server response header including
    //  the status, server version, message time and MIME version.
    //
    //  Server extensions should append other information at the end,
    //  such as Content-type, Content-length etc followed by an extra
    //  '\r\n'.
    //
    //  pData - Zero terminated string pointing to optional
    //      status string (i.e., "401 Access Denied") or NULL for
    //      the default response of "200 OK".
    //
    //  ul1 - Zero terminated string pointing to optional data to be
    //      appended and set with the header.  If NULL, the header will
    //      be terminated with an empty line.
    //

    SF_REQ_SEND_RESPONSE_HEADER,

    //
    //  If the server denies the HTTP request, add the specified headers
    //  to the server error response.
    //
    //  This allows an authentication filter to advertise its services
    //  w/o filtering every request.  Generally the headers will be
    //  WWW-Authenticate headers with custom authentication schemes but
    //  no restriction is placed on what headers may be specified.
    //
    //  pData - Zero terminated string pointing to one or more header lines
    //      with terminating '\r\n'.
    //

    SF_REQ_ADD_HEADERS_ON_DENIAL,

    //
    //  Only used by raw data filters that return SF_STATUS_READ_NEXT
    //
    //  ul1 - size in bytes for the next read
    //

    SF_REQ_SET_NEXT_READ_SIZE,

    //
    //  Used to indicate this request is a proxy request
    //
    //  ul1 - The proxy flags to set
    //      0x00000001 - This is a HTTP proxy request
    //
    //

    SF_REQ_SET_PROXY_INFO,

    //
    //  Returns the connection ID contained in the ConnID field of an
    //  ISAPI Application's Extension Control Block.  This value can be used
    //  as a key to cooridinate shared data between Filters and Applications.
    //
    //  pData - Pointer to DWORD that receives the connection ID.
    //

    SF_REQ_GET_CONNID
};


//
//  These values are returned by the filter entry point when a new request is
//  received indicating their interest in this particular request
//

enum SF_STATUS_TYPE
{
    //
    //  The filter has handled the HTTP request.  The server should disconnect
    //  the session.
    //

    SF_STATUS_REQ_FINISHED = 0x8000000,

    //
    //  Same as SF_STATUS_FINISHED except the server should keep the TCP
    //  session open if the option was negotiated
    //

    SF_STATUS_REQ_FINISHED_KEEP_CONN,

    //
    //  The next filter in the notification chain should be called
    //

    SF_STATUS_REQ_NEXT_NOTIFICATION,

    //
    //  This filter handled the notification.  No other handles should be
    //  called for this particular notification type
    //

    SF_STATUS_REQ_HANDLED_NOTIFICATION,

    //
    //  An error occurred.  The server should use GetLastError() and indicate
    //  the error to the client
    //

    SF_STATUS_REQ_ERROR,

    //
    //  The filter is an opaque stream filter and we're negotiating the
    //  session parameters.  Only valid for raw read notification.
    //

    SF_STATUS_REQ_READ_NEXT
};

//
//  pvNotification points to this structure for all request notification types
//

typedef struct _HTTP_FILTER_CONTEXT
{
    DWORD          cbSize;

    //
    //  This is the structure revision level.
    //

    DWORD          Revision;

    //
    //  Private context information for the server.
    //

    PVOID          ServerContext;
    DWORD          ulReserved;

    //
    //  TRUE if this request is coming over a secure port
    //

    BOOL           fIsSecurePort;

    //
    //  A context that can be used by the filter
    //

    PVOID          pFilterContext;

    //
    //  Server callbacks
    //

    BOOL (WINAPI * GetServerVariable) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        LPSTR                         lpszVariableName,
        LPVOID                        lpvBuffer,
        LPDWORD                       lpdwSize
        );

    BOOL (WINAPI * AddResponseHeaders) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        LPSTR                         lpszHeaders,
        DWORD                         dwReserved
        );

    BOOL (WINAPI * WriteClient)  (
        struct _HTTP_FILTER_CONTEXT * pfc,
        LPVOID                        Buffer,
        LPDWORD                       lpdwBytes,
        DWORD                         dwReserved
        );

    VOID * (WINAPI * AllocMem) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        DWORD                         cbSize,
        DWORD                         dwReserved
        );

    BOOL (WINAPI * ServerSupportFunction) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        enum SF_REQ_TYPE              sfReq,
        PVOID                         pData,
        DWORD                         ul1,
        DWORD                         ul2
        );

} HTTP_FILTER_CONTEXT, *PHTTP_FILTER_CONTEXT;

//
//  This structure is the notification info for the read and send raw data
//  notification types
//

typedef struct _HTTP_FILTER_RAW_DATA
{
    //
    //  This is a pointer to the data for the filter to process.
    //

    PVOID         pvInData;
    DWORD         cbInData;       // Number of valid data bytes
    DWORD         cbInBuffer;     // Total size of buffer

    DWORD         dwReserved;

} HTTP_FILTER_RAW_DATA, *PHTTP_FILTER_RAW_DATA;

//
//  This structure is the notification info for when the server is about to
//  process the client headers
//

typedef struct _HTTP_FILTER_PREPROC_HEADERS
{
    //
    //  Retrieves the specified header value.  Header names should include
    //  the trailing ':'.  The special values 'method', 'url' and 'version'
    //  can be used to retrieve the individual portions of the request line
    //

    BOOL (WINAPI * GetHeader) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        LPSTR                         lpszName,
        LPVOID                        lpvBuffer,
        LPDWORD                       lpdwSize
        );

    //
    //  Replaces this header value to the specified value.  To delete a header,
    //  specified a value of '\0'.
    //

    BOOL (WINAPI * SetHeader) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        LPSTR                         lpszName,
        LPSTR                         lpszValue
        );

    //
    //  Adds the specified header and value
    //

    BOOL (WINAPI * AddHeader) (
        struct _HTTP_FILTER_CONTEXT * pfc,
        LPSTR                         lpszName,
        LPSTR                         lpszValue
        );

    DWORD dwReserved;
} HTTP_FILTER_PREPROC_HEADERS, *PHTTP_FILTER_PREPROC_HEADERS;

//
//  Authentication information for this request.
//

typedef struct _HTTP_FILTER_AUTHENT
{
    //
    //  Pointer to username and password, empty strings for the anonymous user
    //
    //  Client's can overwrite these buffers which are guaranteed to be at
    //  least SF_MAX_USERNAME and SF_MAX_PASSWORD bytes large.
    //

    CHAR * pszUser;
    DWORD  cbUserBuff;

    CHAR * pszPassword;
    DWORD  cbPasswordBuff;

} HTTP_FILTER_AUTHENT, *PHTTP_FILTER_AUTHENT;

//
//  Indicates the server is going to use the specific physical mapping for
//  the specified URL.  Filters can modify the physical path in place.
//

typedef struct _HTTP_FILTER_URL_MAP
{
    const CHAR * pszURL;

    CHAR *       pszPhysicalPath;
    DWORD        cbPathBuff;

} HTTP_FILTER_URL_MAP, *PHTTP_FILTER_URL_MAP;

//
//  Bitfield indicating the requested resource has been denied by the server due
//  to a logon failure, an ACL on a resource, an ISAPI Filter or an
//  ISAPI Application/CGI Application.
//
//  SF_DENIED_BY_CONFIG can appear with SF_DENIED_LOGON if the server
//  configuration did not allow the user to logon.
//

#define SF_DENIED_LOGON             0x00000001
#define SF_DENIED_RESOURCE          0x00000002
#define SF_DENIED_FILTER            0x00000004
#define SF_DENIED_APPLICATION       0x00000008

#define SF_DENIED_BY_CONFIG         0x00010000

typedef struct _HTTP_FILTER_ACCESS_DENIED
{
    const CHAR * pszURL;            // Requesting URL
    const CHAR * pszPhysicalPath;   // Physical path of resource
    DWORD        dwReason;          // Bitfield of SF_DENIED flags

} HTTP_FILTER_ACCESS_DENIED, *PHTTP_FILTER_ACCESS_DENIED;

//
//  The log information about to be written to the server log file.  The
//  string pointers can be replaced but the memory must remain valid until
//  the next notification
//

typedef struct _HTTP_FILTER_LOG
{
    const CHAR * pszClientHostName;
    const CHAR * pszClientUserName;
    const CHAR * pszServerName;
    const CHAR * pszOperation;
    const CHAR * pszTarget;
    const CHAR * pszParameters;

    DWORD  dwHttpStatus;
    DWORD  dwWin32Status;

} HTTP_FILTER_LOG, *PHTTP_FILTER_LOG;

//
//  Notification Flags
//
//  SF_NOTIFY_SECURE_PORT
//  SF_NOTIFY_NONSECURE_PORT
//
//      Indicates whether the application wants to be notified for transactions
//      that are happenning on the server port(s) that support data encryption
//      (such as PCT and SSL), on only the non-secure port(s) or both.
//
//  SF_NOTIFY_READ_RAW_DATA
//
//      Applications are notified after the server reads a block of memory
//      from the client but before the server does any processing on the
//      block.  The data block may contain HTTP headers and entity data.
//
//
//

#define SF_NOTIFY_SECURE_PORT               0x00000001
#define SF_NOTIFY_NONSECURE_PORT            0x00000002

#define SF_NOTIFY_READ_RAW_DATA             0x00008000
#define SF_NOTIFY_PREPROC_HEADERS           0x00004000
#define SF_NOTIFY_AUTHENTICATION            0x00002000
#define SF_NOTIFY_URL_MAP                   0x00001000
#define SF_NOTIFY_ACCESS_DENIED             0x00000800
#define SF_NOTIFY_SEND_RAW_DATA             0x00000400
#define SF_NOTIFY_LOG                       0x00000200
#define SF_NOTIFY_END_OF_NET_SESSION        0x00000100

//
//  Filter ordering flags
//
//  Filters will tend to be notified by their specified
//  ordering.  For ties, notification order is determined by load order.
//
//  SF_NOTIFY_ORDER_HIGH - Authentication or data transformation filters
//  SF_NOTIFY_ORDER_MEDIUM
//  SF_NOTIFY_ORDER_LOW  - Logging filters that want the results of any other
//                      filters might specify this order.
//

#define SF_NOTIFY_ORDER_HIGH               0x00080000
#define SF_NOTIFY_ORDER_MEDIUM             0x00040000
#define SF_NOTIFY_ORDER_LOW                0x00020000
#define SF_NOTIFY_ORDER_DEFAULT            SF_NOTIFY_ORDER_LOW

#define SF_NOTIFY_ORDER_MASK               (SF_NOTIFY_ORDER_HIGH   |    \
                                            SF_NOTIFY_ORDER_MEDIUM |    \
                                            SF_NOTIFY_ORDER_LOW)

//
//  Filter version information, passed to GetFilterVersion
//

typedef struct _HTTP_FILTER_VERSION
{
    //
    //  Version of the spec the server is using
    //

    DWORD  dwServerFilterVersion;

    //
    //  Fields specified by the client
    //

    DWORD  dwFilterVersion;
    CHAR   lpszFilterDesc[SF_MAX_FILTER_DESC_LEN];
    DWORD  dwFlags;


} HTTP_FILTER_VERSION, *PHTTP_FILTER_VERSION;

//
//  A filter DLL's entry point looks like this.  The return code should be
//  an SF_STATUS_TYPE
//
//  NotificationType - Type of notification
//  pvNotification - Pointer to notification specific data
//

DWORD
WINAPI
HttpFilterProc(
    HTTP_FILTER_CONTEXT *      pfc,
    DWORD                      NotificationType,
    VOID *                     pvNotification
    );

BOOL
WINAPI
GetFilterVersion(
    HTTP_FILTER_VERSION * pVer
    );

#ifdef __cplusplus
}
#endif

#endif //_HTTPFILT_H_
