XrdProtocol.hh

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00001 #ifndef __XrdProtocol_H__
00002 #define __XrdProtocol_H__
00003 /******************************************************************************/
00004 /*                                                                            */
00005 /*                        X r d P r o t o c o l . h h                         */
00006 /*                                                                            */
00007 /* (c) 2004 by the Board of Trustees of the Leland Stanford, Jr., University  */
00008 /*   Produced by Andrew Hanushevsky for Stanford University under contract    */
00009 /*              DE-AC02-76-SFO0515 with the Department of Energy              */
00010 /*                                                                            */
00011 /* This file is part of the XRootD software suite.                            */
00012 /*                                                                            */
00013 /* XRootD is free software: you can redistribute it and/or modify it under    */
00014 /* the terms of the GNU Lesser General Public License as published by the     */
00015 /* Free Software Foundation, either version 3 of the License, or (at your     */
00016 /* option) any later version.                                                 */
00017 /*                                                                            */
00018 /* XRootD is distributed in the hope that it will be useful, but WITHOUT      */
00019 /* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or      */
00020 /* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public       */
00021 /* License for more details.                                                  */
00022 /*                                                                            */
00023 /* You should have received a copy of the GNU Lesser General Public License   */
00024 /* along with XRootD in a file called COPYING.LESSER (LGPL license) and file  */
00025 /* COPYING (GPL license).  If not, see <http://www.gnu.org/licenses/>.        */
00026 /*                                                                            */
00027 /* The copyright holder's institutional names and contributor's names may not */
00028 /* be used to endorse or promote products derived from this software without  */
00029 /* specific prior written permission of the institution or contributor.       */
00030 /******************************************************************************/
00031 
00032 #include "Xrd/XrdJob.hh"
00033  
00034 /******************************************************************************/
00035 /*                    X r d P r o t o c o l _ C o n f i g                     */
00036 /******************************************************************************/
00037   
00038 // The following class is passed to the XrdgetProtocol() and XrdgetProtocolPort()
00039 // functions to properly configure the protocol. This object is not stable and 
00040 // the protocol must copy out any values it desires to keep. It may copy the 
00041 // whole object using the supplied copy constructor.
00042 
00043 class XrdSysError;
00044 union XrdNetSockAddr;
00045 class XrdOucTrace;
00046 class XrdBuffManager;
00047 class XrdInet;
00048 class XrdScheduler;
00049 class XrdStats;
00050 
00051 struct sockaddr;
00052 
00053 class XrdProtocol_Config
00054 {
00055 public:
00056 
00057 // The following pointers may be copied; they are stable.
00058 //
00059 XrdSysError    *eDest;       // Stable -> Error Message/Logging Handler
00060 XrdInet        *NetTCP;      // Stable -> Network Object    (@ XrdgetProtocol)
00061 XrdBuffManager *BPool;       // Stable -> Buffer Pool Manager
00062 XrdScheduler   *Sched;       // Stable -> System Scheduler
00063 XrdStats       *Stats;       // Stable -> System Statistics (@ XrdgetProtocol)
00064 void           *Reserved;    // Stable -> Previously, the thread manager
00065 XrdOucTrace    *Trace;       // Stable -> Trace Information
00066 
00067 // The following information must be duplicated; it is unstable.
00068 //
00069 char            *ConfigFN;     // -> Configuration file
00070 int              Format;       // Binary format of this server
00071 int              Port;         // Port number
00072 int              WSize;        // Window size for Port
00073 const char      *AdmPath;      // Admin path
00074 int              AdmMode;      // Admin path mode
00075 const char      *myInst;       // Instance name
00076 const char      *myName;       // Host name
00077 const char      *myProg;       // Program name
00078 union {
00079 const
00080 XrdNetSockAddr  *urAddr;       // Host Address (the actual structure/union)
00081 const
00082 struct sockaddr *myAddr;       // Host address
00083       };
00084 int              ConnMax;      // Max connections
00085 int              readWait;     // Max milliseconds to wait for data
00086 int              idleWait;     // Max milliseconds connection may be idle
00087 int              argc;         // Number of arguments
00088 char           **argv;         // Argument array (prescreened)
00089 char             DebugON;      // True if started with -d option
00090 int              WANPort;      // Port prefered for WAN connections (0 if none)
00091 int              WANWSize;     // Window size for the WANPort
00092 int              hailWait;     // Max milliseconds to wait for data after accept
00093 
00094                  XrdProtocol_Config(XrdProtocol_Config &rhs);
00095                  XrdProtocol_Config() {}
00096                 ~XrdProtocol_Config() {}
00097 };
00098 
00099 /******************************************************************************/
00100 /*                           X r d P r o t o c o l                            */
00101 /******************************************************************************/
00102 
00103 // This class is used by the Link object to process the input stream on a link.
00104 // At least one protocol object exists per Link object. Specific protocols are 
00105 // derived from this pure abstract class since a link can use one of several 
00106 // protocols. Indeed, startup and shutdown are handled by specialized protocols.
00107 
00108 // System configuration obtains an instance of a protocol by calling
00109 // XrdgetProtocol(), which must exist in the shared library.
00110 // This instance is used as the base pointer for Alloc(), Configure(), and
00111 // Match(). Unfortuantely, they cannot be static given the silly C++ rules.
00112 
00113 class XrdLink;
00114   
00115 class XrdProtocol : public XrdJob
00116 {
00117 public:
00118 
00119 // Match()     is invoked when a new link is created and we are trying
00120 //             to determine if this protocol can handle the link. It must
00121 //             return a protocol object if it can and NULL (0), otherwise.
00122 //
00123 virtual XrdProtocol  *Match(XrdLink *lp) = 0;
00124 
00125 // Process()   is invoked when a link has data waiting to be read
00126 //
00127 virtual int           Process(XrdLink *lp) = 0;
00128 
00129 // Recycle()   is invoked when this object is no longer needed. The method is
00130 //             passed the number of seconds the protocol was connected to the
00131 //             link and the reason for the disconnection, if any.
00132 //
00133 virtual void          Recycle(XrdLink *lp=0,int consec=0,const char *reason=0)=0;
00134 
00135 // Stats()     is invoked when we need statistics about all instances of the
00136 //             protocol. If a buffer is supplied, it must return a null 
00137 //             terminated string in the supplied buffer and the return value
00138 //             is the number of bytes placed in the buffer defined by C99 for 
00139 //             snprintf(). If no buffer is supplied, the method should return
00140 //             the maximum number of characters that could have been returned.
00141 //             Regardless of the buffer value, if do_sync is true, the method
00142 //             should include any local statistics in the global data (if any)
00143 //             prior to performing any action.
00144 //
00145 virtual int           Stats(char *buff, int blen, int do_sync=0) = 0;
00146 
00147             XrdProtocol(const char *jname): XrdJob(jname) {}
00148 virtual    ~XrdProtocol() {}
00149 };
00150 
00151 /******************************************************************************/
00152 /*                        X r d g e t P r o t o c o l                         */
00153 /******************************************************************************/
00154   
00155 /* This extern "C" function must be defined in the shared library plug-in
00156    implementing your protocol. It is called to obtain an instance of your
00157    protocol. This allows protocols to live outside of the protocol driver
00158    (i.e., to be loaded at run-time). The call is made after the call to
00159    XrdgetProtocolPort() to determine the port to be used (see below) which
00160    allows e network object (NetTCP) to be proerly defined and it's pointer
00161    is passed in the XrdProtocol_Config object for your use.
00162 
00163    Required return values:
00164    Success: Pointer to XrdProtocol object.
00165    Failure: Null pointer (i.e. 0) which causes the program to exit.
00166 
00167 extern "C"  // This is in a comment!
00168 {
00169        XrdProtocol *XrdgetProtocol(const char *protocol_name, char *parms,
00170                                    XrdProtocol_Config *pi) {....}
00171 }
00172 */
00173   
00174 /******************************************************************************/
00175 /*                    X r d g e t P r o t o c o l P o r t                     */
00176 /******************************************************************************/
00177   
00178 /* This extern "C" function must be defined for statically linked protocols
00179    but is optional for protocols defined as a shared library plug-in if the
00180    rules determining which port number to use is sufficient for your protocol.
00181    The function is called to obtain the actual port number to be used by the
00182    the protocol. The default port number is noted in XrdProtocol_Config Port.
00183    Initially, it has one of the fllowing values:
00184    <0 -> No port was specified.
00185    =0 -> An erbitrary port will be assigned.
00186    >0 -> This port number was specified.
00187 
00188    XrdgetProtoclPort() must return:
00189    <0 -> Failure is indicated and we terminate
00190    =0 -> Use an arbitrary port (even if this equals Port)
00191    >0 -> The returned port number must be used (even if it equals Port)
00192 
00193    When we finally call XrdgetProtocol(), the actual port number is indicated
00194    in Port and the network object is defined in NetTCP and bound to the port.
00195 
00196    Final Caveats: 1.  The network object (NetTCP) is not defined until
00197                       XrdgetProtocol() is called.
00198 
00199                   2.  The statistics object (Stats) is not defined until
00200                       XrdgetProtocol() is called.
00201 
00202                   3.  When the protocol is loaded from a shared library, you need
00203                       need not define XrdgetProtocolPort() if the standard port
00204                       determination scheme is sufficient.
00205 
00206 extern "C"  // This is in a comment!
00207 {
00208        int XrdgetProtocolPort(const char *protocol_name, char *parms,
00209                               XrdProtocol_Config *pi) {....}
00210 }
00211 */
00212 #endif

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