]> arthur.barton.de Git - ngircd-alex.git/blobdiff - src/ngircd/irc-login.c
New configuration option "PAMIsOptional"
[ngircd-alex.git] / src / ngircd / irc-login.c
index 8e77e7fe34ddcefde11788fd00a5e15c0c7e77f9..bbb2f0d5e430c88a904514ff77bbfa3d3ed49b92 100644 (file)
@@ -1,34 +1,39 @@
 /*
  * ngIRCd -- The Next Generation IRC Daemon
- * Copyright (c)2001-2010 Alexander Barton (alex@barton.de)
+ * Copyright (c)2001-2011 Alexander Barton (alex@barton.de) and Contributors.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  * Please read the file COPYING, README and AUTHORS for more information.
- *
- * Login and logout
  */
 
-
 #include "portab.h"
 
+/**
+ * @file
+ * Login and logout
+ */
+
 #include "imp.h"
 #include <assert.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <strings.h>
+#include <signal.h>
+#include <unistd.h>
 
 #include "ngircd.h"
-#include "resolve.h"
 #include "conn-func.h"
+#include "class.h"
 #include "conf.h"
-#include "client.h"
 #include "channel.h"
+#include "io.h"
 #include "log.h"
 #include "messages.h"
+#include "pam.h"
 #include "parse.h"
 #include "irc.h"
 #include "irc-info.h"
 
 
 static bool Hello_User PARAMS(( CLIENT *Client ));
+static bool Hello_User_PostAuth PARAMS(( CLIENT *Client ));
 static void Kill_Nick PARAMS(( char *Nick, char *Reason ));
 static void Introduce_Client PARAMS((CLIENT *To, CLIENT *Client, int Type));
+static void Reject_Client PARAMS((CLIENT *Client, const char *InternalReason));
+
 static void cb_introduceClient PARAMS((CLIENT *Client, CLIENT *Prefix,
                                       void *i));
 
+#ifdef PAM
+static void cb_Read_Auth_Result PARAMS((int r_fd, UNUSED short events));
+#endif
 
 /**
- * Handler for the IRC command "PASS".
+ * Handler for the IRC "PASS" command.
+ *
  * See RFC 2813 section 4.1.1, and RFC 2812 section 3.1.1.
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
  */
 GLOBAL bool
 IRC_PASS( CLIENT *Client, REQUEST *Req )
@@ -135,16 +151,17 @@ IRC_PASS( CLIENT *Client, REQUEST *Req )
                if (type && strcmp(type, PROTOIRCPLUS) == 0) {
                        /* The peer seems to be a server which supports the
                         * IRC+ protocol (see doc/Protocol.txt). */
-                       serverver = ptr + 1;
-                       flags = strchr(serverver, ':');
+                       serverver = ptr ? ptr + 1 : "?";
+                       flags = strchr(ptr ? serverver : impl, ':');
                        if (flags) {
                                *flags = '\0';
                                flags++;
                        } else
                                flags = "";
                        Log(LOG_INFO,
-                           "Peer announces itself as %s-%s using protocol %d.%d/IRC+ (flags: \"%s\").",
-                           impl, serverver, protohigh, protolow, flags);
+                           "Peer on conenction %d announces itself as %s-%s using protocol %d.%d/IRC+ (flags: \"%s\").",
+                           Client_Conn(Client), impl, serverver,
+                           protohigh, protolow, flags);
                } else {
                        /* The peer seems to be a server supporting the
                         * "original" IRC protocol (RFC 2813). */
@@ -153,8 +170,9 @@ IRC_PASS( CLIENT *Client, REQUEST *Req )
                        else
                                flags = "";
                        Log(LOG_INFO,
-                           "Peer announces itself as \"%s\" using protocol %d.%d (flags: \"%s\").",
-                           impl, protohigh, protolow, flags);
+                           "Peer on connection %d announces itself as \"%s\" using protocol %d.%d (flags: \"%s\").",
+                           Client_Conn(Client), impl,
+                           protohigh, protolow, flags);
                }
                Client_SetFlags(Client, flags);
        }
@@ -164,10 +182,17 @@ IRC_PASS( CLIENT *Client, REQUEST *Req )
 
 
 /**
- * IRC "NICK" command.
+ * Handler for the IRC "NICK" command.
+ *
+ * See RFC 2812, 3.1.2 "Nick message", and RFC 2813, 4.1.3 "Nick".
+ *
  * This function implements the IRC command "NICK" which is used to register
  * with the server, to change already registered nicknames and to introduce
  * new users which are connected to other servers.
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
  */
 GLOBAL bool
 IRC_NICK( CLIENT *Client, REQUEST *Req )
@@ -247,6 +272,17 @@ IRC_NICK( CLIENT *Client, REQUEST *Req )
                        /* Register new nickname of this client */
                        Client_SetID( target, Req->argv[0] );
 
+#ifndef STRICT_RFC
+                       if (Conf_AuthPing) {
+                               Conn_SetAuthPing(Client_Conn(Client), rand());
+                               IRC_WriteStrClient(Client, "PING :%ld",
+                                       Conn_GetAuthPing(Client_Conn(Client)));
+                               LogDebug("Connection %d: sent AUTH PING %ld ...",
+                                       Client_Conn(Client),
+                                       Conn_GetAuthPing(Client_Conn(Client)));
+                       }
+#endif
+
                        /* If we received a valid USER command already then
                         * register the new client! */
                        if( Client_Type( Client ) == CLIENT_GOTUSER )
@@ -369,7 +405,13 @@ IRC_NICK( CLIENT *Client, REQUEST *Req )
 
 
 /**
- * Handler for the IRC command "USER".
+ * Handler for the IRC "USER" command.
+ *
+ * See RFC 2812, 3.1.3 "User message".
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
  */
 GLOBAL bool
 IRC_USER(CLIENT * Client, REQUEST * Req)
@@ -403,6 +445,7 @@ IRC_USER(CLIENT * Client, REQUEST * Req)
 #else
                Client_SetUser(Client, Req->argv[0], false);
 #endif
+               Client_SetOrigUser(Client, Req->argv[0]);
 
                /* "Real name" or user info text: Don't set it to the empty
                 * string, the original ircd can't deal with such "real names"
@@ -435,6 +478,7 @@ IRC_USER(CLIENT * Client, REQUEST * Req)
                                                  Req->prefix);
 
                Client_SetUser(c, Req->argv[0], true);
+               Client_SetOrigUser(c, Req->argv[0]);
                Client_SetHostname(c, Req->argv[1]);
                Client_SetInfo(c, Req->argv[3]);
 
@@ -460,12 +504,18 @@ IRC_USER(CLIENT * Client, REQUEST * Req)
 
 
 /**
- * Handler for the IRC command "SERVICE".
+ * Handler for the IRC "SERVICE" command.
+ *
  * This function implements IRC Services registration using the SERVICE command
  * defined in RFC 2812 3.1.6 and RFC 2813 4.1.4.
+ *
  * At the moment ngIRCd doesn't support directly linked services, so this
  * function returns ERR_ERRONEUSNICKNAME when the SERVICE command has not been
  * received from a peer server.
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED..
  */
 GLOBAL bool
 IRC_SERVICE(CLIENT *Client, REQUEST *Req)
@@ -558,8 +608,14 @@ IRC_SERVICE(CLIENT *Client, REQUEST *Req)
 
 
 /**
- * Handler for the IRC command "WEBIRC".
- * Syntax: WEBIRC <password> <username> <real-hostname> <real-IP-address>
+ * Handler for the IRC "WEBIRC" command.
+ *
+ * See doc/Protocol.txt, section II.4:
+ * "Update webchat/proxy client information".
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
  */
 GLOBAL bool
 IRC_WEBIRC(CLIENT *Client, REQUEST *Req)
@@ -577,43 +633,58 @@ IRC_WEBIRC(CLIENT *Client, REQUEST *Req)
                 Client_Conn(Client), Req->argv[1], Req->argv[2], Req->argv[3]);
 
        Client_SetUser(Client, Req->argv[1], true);
+       Client_SetOrigUser(Client, Req->argv[1]);
        Client_SetHostname(Client, Req->argv[2]);
        return CONNECTED;
 } /* IRC_WEBIRC */
 
 
+/**
+ * Handler for the IRC "QUIT" command.
+ *
+ * See RFC 2812, 3.1.7 "Quit", and RFC 2813, 4.1.5 "Quit".
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
+ */
 GLOBAL bool
 IRC_QUIT( CLIENT *Client, REQUEST *Req )
 {
        CLIENT *target;
        char quitmsg[LINE_LEN];
 
-       assert( Client != NULL );
-       assert( Req != NULL );
+       assert(Client != NULL);
+       assert(Req != NULL);
 
        /* Wrong number of arguments? */
-       if( Req->argc > 1 )
-               return IRC_WriteStrClient( Client, ERR_NEEDMOREPARAMS_MSG, Client_ID( Client ), Req->command );
+       if (Req->argc > 1)
+               return IRC_WriteStrClient(Client, ERR_NEEDMOREPARAMS_MSG,
+                                         Client_ID(Client), Req->command);
 
        if (Req->argc == 1)
                strlcpy(quitmsg, Req->argv[0], sizeof quitmsg);
 
-       if ( Client_Type( Client ) == CLIENT_SERVER )
-       {
+       if (Client_Type(Client) == CLIENT_SERVER) {
                /* Server */
-               target = Client_Search( Req->prefix );
-               if( ! target )
-               {
-                       Log( LOG_WARNING, "Got QUIT from %s for unknown client!?", Client_ID( Client ));
+               target = Client_Search(Req->prefix);
+               if (!target) {
+                       Log(LOG_WARNING,
+                           "Got QUIT from %s for unknown client!?",
+                           Client_ID(Client));
                        return CONNECTED;
                }
 
-               Client_Destroy( target, "Got QUIT command.", Req->argc == 1 ? quitmsg : NULL, true);
-
-               return CONNECTED;
-       }
-       else
-       {
+               if (target != Client) {
+                       Client_Destroy(target, "Got QUIT command.",
+                                      Req->argc == 1 ? quitmsg : NULL, true);
+                       return CONNECTED;
+               } else {
+                       Conn_Close(Client_Conn(Client), "Got QUIT command.",
+                                  Req->argc == 1 ? quitmsg : NULL, true);
+                       return DISCONNECTED;
+               }
+       } else {
                if (Req->argc == 1 && quitmsg[0] != '\"') {
                        /* " " to avoid confusion */
                        strlcpy(quitmsg, "\"", sizeof quitmsg);
@@ -622,13 +693,46 @@ IRC_QUIT( CLIENT *Client, REQUEST *Req )
                }
 
                /* User, Service, or not yet registered */
-               Conn_Close( Client_Conn( Client ), "Got QUIT command.", Req->argc == 1 ? quitmsg : NULL, true);
+               Conn_Close(Client_Conn(Client), "Got QUIT command.",
+                          Req->argc == 1 ? quitmsg : NULL, true);
 
                return DISCONNECTED;
        }
 } /* IRC_QUIT */
 
 
+#ifndef STRICT_RFC
+
+/**
+ * Handler for HTTP command, e.g. GET and POST
+ *
+ * We handle these commands here to avoid the quite long timeout when
+ * some user tries to access this IRC daemon using an web browser ...
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
+ */
+GLOBAL bool
+IRC_QUIT_HTTP( CLIENT *Client, REQUEST *Req )
+{
+       Req->argc = 1;
+       Req->argv[0] = "Oops, HTTP request received? This is IRC!";
+       return IRC_QUIT(Client, Req);
+} /* IRC_QUIT_HTTP */
+
+#endif
+
+
+/**
+ * Handler for the IRC "PING" command.
+ *
+ * See RFC 2812, 3.7.2 "Ping message".
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
+ */
 GLOBAL bool
 IRC_PING(CLIENT *Client, REQUEST *Req)
 {
@@ -698,22 +802,45 @@ IRC_PING(CLIENT *Client, REQUEST *Req)
 } /* IRC_PING */
 
 
+/**
+ * Handler for the IRC "PONG" command.
+ *
+ * See RFC 2812, 3.7.3 "Pong message".
+ *
+ * @param Client       The client from which this command has been received.
+ * @param Req          Request structure with prefix and all parameters.
+ * @returns            CONNECTED or DISCONNECTED.
+ */
 GLOBAL bool
 IRC_PONG(CLIENT *Client, REQUEST *Req)
 {
        CLIENT *target, *from;
+       CONN_ID conn;
+#ifndef STRICT_RFC
+       long auth_ping;
+#endif
        char *s;
 
        assert(Client != NULL);
        assert(Req != NULL);
 
        /* Wrong number of arguments? */
-       if (Req->argc < 1)
-               return IRC_WriteStrClient(Client, ERR_NOORIGIN_MSG,
-                                         Client_ID(Client));
-       if (Req->argc > 2)
-               return IRC_WriteStrClient(Client, ERR_NEEDMOREPARAMS_MSG,
-                                         Client_ID(Client), Req->command);
+       if (Req->argc < 1) {
+               if (Client_Type(Client) == CLIENT_USER)
+                       return IRC_WriteStrClient(Client, ERR_NOORIGIN_MSG,
+                                                 Client_ID(Client));
+               else
+                       return CONNECTED;
+       }
+       if (Req->argc > 2) {
+               if (Client_Type(Client) == CLIENT_USER)
+                       return IRC_WriteStrClient(Client,
+                                                 ERR_NEEDMOREPARAMS_MSG,
+                                                 Client_ID(Client),
+                                                 Req->command);
+               else
+                       return CONNECTED;
+       }
 
        /* Forward? */
        if (Req->argc == 2 && Client_Type(Client) == CLIENT_SERVER) {
@@ -742,32 +869,214 @@ IRC_PONG(CLIENT *Client, REQUEST *Req)
 
        /* The connection timestamp has already been updated when the data has
         * been read from so socket, so we don't need to update it here. */
+
+       conn = Client_Conn(Client);
+
+#ifndef STRICT_RFC
+       /* Check authentication PING-PONG ... */
+       auth_ping = Conn_GetAuthPing(conn);
+       if (auth_ping) {
+               LogDebug("AUTH PONG: waiting for token \"%ld\", got \"%s\" ...",
+                        auth_ping, Req->argv[0]);
+               if (auth_ping == atoi(Req->argv[0])) {
+                       Conn_SetAuthPing(conn, 0);
+                       if (Client_Type(Client) == CLIENT_WAITAUTHPING)
+                               Hello_User(Client);
+               } else
+                       if (!IRC_WriteStrClient(Client,
+                                       "To connect, type /QUOTE PONG %ld",
+                                       auth_ping))
+                               return DISCONNECTED;
+       }
+#endif
+
 #ifdef DEBUG
-       if (Client_Conn(Client) > NONE)
+       if (conn > NONE)
                Log(LOG_DEBUG,
-                       "Connection %d: received PONG. Lag: %ld seconds.",
-                       Client_Conn(Client),
+                       "Connection %d: received PONG. Lag: %ld seconds.", conn,
                        time(NULL) - Conn_LastPing(Client_Conn(Client)));
        else
                 Log(LOG_DEBUG,
-                       "Connection %d: received PONG.", Client_Conn(Client));
+                       "Connection %d: received PONG.", conn);
 #endif
        return CONNECTED;
 } /* IRC_PONG */
 
 
+/**
+ * Initiate client registration.
+ *
+ * This function is called after the daemon received the required NICK and
+ * USER commands of a new client. If the daemon is compiled with support for
+ * PAM, the authentication sub-processs is forked; otherwise the global server
+ * password is checked.
+ *
+ * @param Client       The client logging in.
+ * @returns            CONNECTED or DISCONNECTED.
+ */
 static bool
 Hello_User(CLIENT * Client)
 {
+#ifdef PAM
+       int pipefd[2], result;
+       pid_t pid;
+#endif
+       CONN_ID conn;
+
        assert(Client != NULL);
+       conn = Client_Conn(Client);
 
-       /* Check password ... */
+#ifndef STRICT_RFC
+       if (Conf_AuthPing) {
+               /* Did we receive the "auth PONG" already? */
+               if (Conn_GetAuthPing(conn)) {
+                       Client_SetType(Client, CLIENT_WAITAUTHPING);
+                       LogDebug("Connection %d: Waiting for AUTH PONG ...", conn);
+                       return CONNECTED;
+               }
+       }
+#endif
+
+#ifdef PAM
+       if (!Conf_PAM) {
+               /* Don't do any PAM authentication at all, instead emulate
+                * the beahiour of the daemon compiled without PAM support:
+                * because there can't be any "server password", all
+                * passwords supplied are classified as "wrong". */
+               if(Client_Password(Client)[0] == '\0')
+                       return Hello_User_PostAuth(Client);
+               Reject_Client(Client, "non-empty password");
+               return DISCONNECTED;
+       }
+
+       if (Conf_PAMIsOptional && strcmp(Client_Password(Client), "") == 0) {
+               /* Clients are not required to send a password and to be PAM-
+                * authenticated at all. If not, they won't become "identified"
+                * and keep the "~" in their supplied user name.
+                * Therefore it is sensible to either set Conf_PAMisOptional or
+                * to enable IDENT lookups -- not both. */
+               return Hello_User_PostAuth(Client);
+       }
+
+       /* Fork child process for PAM authentication; and make sure that the
+        * process timeout is set higher than the login timeout! */
+       pid = Proc_Fork(Conn_GetProcStat(conn), pipefd,
+                       cb_Read_Auth_Result, Conf_PongTimeout + 1);
+       if (pid > 0) {
+               LogDebug("Authenticator for connection %d created (PID %d).",
+                        conn, pid);
+               return CONNECTED;
+       } else {
+               /* Sub process */
+               Log_Init_Subprocess("Auth");
+               Conn_CloseAllSockets(NONE);
+               result = PAM_Authenticate(Client);
+               if (write(pipefd[1], &result, sizeof(result)) != sizeof(result))
+                       Log_Subprocess(LOG_ERR,
+                                      "Failed to pipe result to parent!");
+               Log_Exit_Subprocess("Auth");
+               exit(0);
+       }
+#else
+       /* Check global server password ... */
        if (strcmp(Client_Password(Client), Conf_ServerPwd) != 0) {
                /* Bad password! */
-               Log(LOG_ERR,
-                   "Client \"%s\" rejected (connection %d): Bad password!",
-                   Client_Mask(Client), Client_Conn(Client));
-               Conn_Close(Client_Conn(Client), NULL, "Bad password", true);
+               Reject_Client(Client, "bad server password");
+               return DISCONNECTED;
+       }
+       return Hello_User_PostAuth(Client);
+#endif
+}
+
+
+#ifdef PAM
+
+/**
+ * Read result of the authenticatior sub-process from pipe
+ *
+ * @param r_fd         File descriptor of the pipe.
+ * @param events       (ignored IO specification)
+ */
+static void
+cb_Read_Auth_Result(int r_fd, UNUSED short events)
+{
+       CONN_ID conn;
+       CLIENT *client;
+       int result;
+       size_t len;
+       PROC_STAT *proc;
+
+       LogDebug("Auth: Got callback on fd %d, events %d", r_fd, events);
+       conn = Conn_GetFromProc(r_fd);
+       if (conn == NONE) {
+               /* Ops, none found? Probably the connection has already
+                * been closed!? We'll ignore that ... */
+               io_close(r_fd);
+               LogDebug("Auth: Got callback for unknown connection!?");
+               return;
+       }
+       proc = Conn_GetProcStat(conn);
+       client = Conn_GetClient(conn);
+
+       /* Read result from pipe */
+       len = Proc_Read(proc, &result, sizeof(result));
+       Proc_Close(proc);
+       if (len == 0)
+               return;
+
+       if (len != sizeof(result)) {
+               Log(LOG_CRIT, "Auth: Got malformed result!");
+               Reject_Client(client, "internal error");
+               return;
+       }
+
+       if (result == true) {
+               Client_SetUser(client, Client_OrigUser(client), true);
+               (void)Hello_User_PostAuth(client);
+       } else
+               Reject_Client(client, "bad password");
+}
+
+#endif
+
+
+/**
+ * Reject a client because of wrong password.
+ *
+ * This function is called either when the global server password or a password
+ * checked using PAM has been wrong.
+ *
+ * @param Client       The client to reject.
+ */
+static void
+Reject_Client(CLIENT *Client, const char *InternalReason)
+{
+       Log(LOG_ERR,
+           "User \"%s\" rejected (connection %d): %s!",
+           Client_Mask(Client), Client_Conn(Client), InternalReason);
+       Conn_Close(Client_Conn(Client), InternalReason,
+                  "Access denied! Bad password?", true);
+}
+
+
+/**
+ * Finish client registration.
+ *
+ * Introduce the new client to the network and send all "hello messages"
+ * to it after authentication has been succeeded.
+ *
+ * @param Client       The client logging in.
+ * @returns            CONNECTED or DISCONNECTED.
+ */
+static bool
+Hello_User_PostAuth(CLIENT *Client)
+{
+       if (Class_IsMember(CLASS_GLINE, Client)) {
+               Reject_Client(Client, "G-Line'd");
+               return DISCONNECTED;
+       }
+       if (Class_IsMember(CLASS_KLINE, Client)) {
+               Reject_Client(Client, "K-Line'd");
                return DISCONNECTED;
        }
 
@@ -804,27 +1113,42 @@ Hello_User(CLIENT * Client)
        IRC_SetPenalty(Client, 1);
 
        return CONNECTED;
-} /* Hello_User */
+}
 
 
+/**
+ * Kill all users with a specific nick name in the network.
+ *
+ * @param Nick         Nick name.
+ * @param Reason       Reason for the KILL.
+ */
 static void
-Kill_Nick( char *Nick, char *Reason )
+Kill_Nick(char *Nick, char *Reason)
 {
        REQUEST r;
 
-       assert( Nick != NULL );
-       assert( Reason != NULL );
+       assert (Nick != NULL);
+       assert (Reason != NULL);
 
-       r.prefix = (char *)Client_ThisServer( );
+       r.prefix = NULL;
        r.argv[0] = Nick;
        r.argv[1] = Reason;
        r.argc = 2;
 
-       Log( LOG_ERR, "User(s) with nick \"%s\" will be disconnected: %s", Nick, Reason );
-       IRC_KILL( Client_ThisServer( ), &r );
+       Log(LOG_ERR, "User(s) with nick \"%s\" will be disconnected: %s",
+           Nick, Reason);
+
+       IRC_KILL(Client_ThisServer(), &r);
 } /* Kill_Nick */
 
 
+/**
+ * Introduce a new user or service client in the network.
+ *
+ * @param From         Remote server introducing the client or NULL (local).
+ * @param Client       New client.
+ * @param Type         Type of the client (CLIENT_USER or CLIENT_SERVICE).
+ */
 static void
 Introduce_Client(CLIENT *From, CLIENT *Client, int Type)
 {
@@ -858,6 +1182,16 @@ Introduce_Client(CLIENT *From, CLIENT *Client, int Type)
 } /* Introduce_Client */
 
 
+/**
+ * Introduce a new user or service client to a remote server.
+ *
+ * This function differentiates between RFC1459 and RFC2813 server links and
+ * generates the appropriate commands to register the new user or service.
+ *
+ * @param To           The remote server to inform.
+ * @param Prefix       Prefix for the generated commands.
+ * @param data         CLIENT structure of the new client.
+ */
 static void
 cb_introduceClient(CLIENT *To, CLIENT *Prefix, void *data)
 {