Remove code for unregistered clients from check_pings_list()

[solanum.git] / src / client.c

/*
 *  charybdis: an advanced ircd.
 *  client.c: Controls clients.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2005 ircd-ratbox development team
 *  Copyright (C) 2007 William Pitcock
 *
 *  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.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 *  $Id: client.c 3514 2007-06-06 16:25:21Z nenolod $
 */
#include "stdinc.h"
#include "config.h"

#include "tools.h"
#include "client.h"
#include "class.h"
#include "common.h"
#include "event.h"
#include "hash.h"
#include "irc_string.h"
#include "sprintf_irc.h"
#include "ircd.h"
#include "s_gline.h"
#include "numeric.h"
#include "packet.h"
#include "s_auth.h"
#include "commio.h"
#include "s_conf.h"
#include "s_newconf.h"
#include "s_log.h"
#include "s_serv.h"
#include "s_stats.h"
#include "send.h"
#include "whowas.h"
#include "s_user.h"
#include "linebuf.h"
#include "hash.h"
#include "memory.h"
#include "hostmask.h"
#include "balloc.h"
#include "listener.h"
#include "hook.h"
#include "msg.h"
#include "monitor.h"
#include "blacklist.h"
#include "reject.h"
#include "scache.h"
#include "irc_dictionary.h"

#define DEBUG_EXITED_CLIENTS

static void check_pings_list(dlink_list * list);
static void check_unknowns_list(dlink_list * list);
static void free_exited_clients(void *unused);
static void exit_aborted_clients(void *unused);

static int exit_remote_client(struct Client *, struct Client *, struct Client *,const char *);
static int exit_remote_server(struct Client *, struct Client *, struct Client *,const char *);
static int exit_local_client(struct Client *, struct Client *, struct Client *,const char *);
static int exit_unknown_client(struct Client *, struct Client *, struct Client *,const char *);
static int exit_local_server(struct Client *, struct Client *, struct Client *,const char *);
static int qs_server(struct Client *, struct Client *, struct Client *, const char *comment);

static EVH check_pings;

extern BlockHeap *client_heap;
extern BlockHeap *lclient_heap;
extern BlockHeap *pclient_heap;

extern char current_uid[IDLEN];

struct Dictionary *nd_dict = NULL;

enum
{
        D_LINED,
        K_LINED,
        G_LINED
};

dlink_list dead_list;
#ifdef DEBUG_EXITED_CLIENTS
static dlink_list dead_remote_list;
#endif

struct abort_client
{
        dlink_node node;
        struct Client *client;
        char notice[REASONLEN];
};

static dlink_list abort_list;


/*
 * init_client
 *
 * inputs       - NONE
 * output       - NONE
 * side effects - initialize client free memory
 */
void
init_client(void)
{
        /*
         * start off the check ping event ..  -- adrian
         * Every 30 seconds is plenty -- db
         */
        client_heap = BlockHeapCreate(sizeof(struct Client), CLIENT_HEAP_SIZE);
        lclient_heap = BlockHeapCreate(sizeof(struct LocalUser), LCLIENT_HEAP_SIZE);
        pclient_heap = BlockHeapCreate(sizeof(struct PreClient), PCLIENT_HEAP_SIZE);
        eventAddIsh("check_pings", check_pings, NULL, 30);
        eventAddIsh("free_exited_clients", &free_exited_clients, NULL, 4);
        eventAddIsh("exit_aborted_clients", exit_aborted_clients, NULL, 1);

        nd_dict = irc_dictionary_create(irccmp);
}


/*
 * make_client - create a new Client struct and set it to initial state.
 *
 *      from == NULL,   create local client (a client connected
 *                      to a socket).
 *
 *      from,   create remote client (behind a socket
 *                      associated with the client defined by
 *                      'from'). ('from' is a local client!!).
 */
struct Client *
make_client(struct Client *from)
{
        struct Client *client_p = NULL;
        struct LocalUser *localClient;

        client_p = BlockHeapAlloc(client_heap);

        if(from == NULL)
        {
                client_p->from = client_p;      /* 'from' of local client is self! */

                localClient = (struct LocalUser *) BlockHeapAlloc(lclient_heap);
                SetMyConnect(client_p);
                client_p->localClient = localClient;

                client_p->localClient->lasttime = client_p->localClient->firsttime = CurrentTime;

                client_p->localClient->fd = -1;
                client_p->localClient->ctrlfd = -1;

                client_p->preClient = (struct PreClient *) BlockHeapAlloc(pclient_heap);

                /* as good a place as any... */
                dlinkAdd(client_p, &client_p->localClient->tnode, &unknown_list);
        }
        else
        {                       /* from is not NULL */
                client_p->localClient = NULL;
                client_p->preClient = NULL;
                client_p->from = from;  /* 'from' of local client is self! */
        }
        
        SetUnknown(client_p);
        strcpy(client_p->username, "unknown");

        return client_p;
}

void
free_pre_client(struct Client *client_p)
{
        struct Blacklist *blptr;

        s_assert(NULL != client_p);

        if(client_p->preClient == NULL)
                return;

        blptr = client_p->preClient->dnsbl_listed;
        if (blptr != NULL)
                unref_blacklist(blptr);
        abort_blacklist_queries(client_p);
        BlockHeapFree(pclient_heap, client_p->preClient);
        client_p->preClient = NULL;
}

static void
free_local_client(struct Client *client_p)
{
        s_assert(NULL != client_p);
        s_assert(&me != client_p);

        if(client_p->localClient == NULL)
                return;

        /*
         * clean up extra sockets from P-lines which have been discarded.
         */
        if(client_p->localClient->listener)
        {
                s_assert(0 < client_p->localClient->listener->ref_count);
                if(0 == --client_p->localClient->listener->ref_count
                   && !client_p->localClient->listener->active)
                        free_listener(client_p->localClient->listener);
                client_p->localClient->listener = 0;
        }

        if(client_p->localClient->fd >= 0)
                comm_close(client_p->localClient->fd);

        if(client_p->localClient->passwd)
        {
                memset(client_p->localClient->passwd, 0,
                        strlen(client_p->localClient->passwd));
                MyFree(client_p->localClient->passwd);
        }

        MyFree(client_p->localClient->challenge);
        MyFree(client_p->localClient->fullcaps);
        MyFree(client_p->localClient->opername);
        MyFree(client_p->localClient->mangledhost);

        BlockHeapFree(lclient_heap, client_p->localClient);
        client_p->localClient = NULL;
}

void
free_client(struct Client *client_p)
{
        s_assert(NULL != client_p);
        s_assert(&me != client_p);
        free_local_client(client_p);
        free_pre_client(client_p);
        BlockHeapFree(client_heap, client_p);
}

/*
 * check_pings - go through the local client list and check activity
 * kill off stuff that should die
 *
 * inputs       - NOT USED (from event)
 * output       - next time_t when check_pings() should be called again
 * side effects - 
 *
 *
 * A PING can be sent to clients as necessary.
 *
 * Client/Server ping outs are handled.
 */

/*
 * Addon from adrian. We used to call this after nextping seconds,
 * however I've changed it to run once a second. This is only for
 * PING timeouts, not K/etc-line checks (thanks dianora!). Having it
 * run once a second makes life a lot easier - when a new client connects
 * and they need a ping in 4 seconds, if nextping was set to 20 seconds
 * we end up waiting 20 seconds. This is stupid. :-)
 * I will optimise (hah!) check_pings() once I've finished working on
 * tidying up other network IO evilnesses.
 *     -- adrian
 */

static void
check_pings(void *notused)
{
        check_pings_list(&lclient_list);
        check_pings_list(&serv_list);
        check_unknowns_list(&unknown_list);
}

/*
 * Check_pings_list()
 *
 * inputs       - pointer to list to check
 * output       - NONE
 * side effects - 
 */
static void
check_pings_list(dlink_list * list)
{
        char scratch[32];       /* way too generous but... */
        struct Client *client_p;        /* current local client_p being examined */
        int ping = 0;           /* ping time value from client */
        dlink_node *ptr, *next_ptr;

        DLINK_FOREACH_SAFE(ptr, next_ptr, list->head)
        {
                client_p = ptr->data;

                /*
                 ** Note: No need to notify opers here. It's
                 ** already done when "FLAGS_DEADSOCKET" is set.
                 */
                if(!MyConnect(client_p) || IsDead(client_p))
                        continue;

                if(IsPerson(client_p))
                {
                        if(!IsExemptKline(client_p) &&
                           GlobalSetOptions.idletime &&
                           !IsOper(client_p) &&
                           !IsIdlelined(client_p) &&
                           ((CurrentTime - client_p->localClient->last) > GlobalSetOptions.idletime))
                        {
                                struct ConfItem *aconf;

                                aconf = make_conf();
                                aconf->status = CONF_KILL;

                                DupString(aconf->host, client_p->host);
                                DupString(aconf->passwd, "idle exceeder");
                                DupString(aconf->user, client_p->username);
                                aconf->port = 0;
                                aconf->hold = CurrentTime + 60;
                                add_temp_kline(aconf);
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                     "Idle time limit exceeded for %s - temp k-lining",
                                                     get_client_name(client_p, HIDE_IP));

                                exit_client(client_p, client_p, &me, aconf->passwd);
                                continue;
                        }
                }

                ping = get_client_ping(client_p);

                if(ping < (CurrentTime - client_p->localClient->lasttime))
                {
                        /*
                         * If the client/server hasnt talked to us in 2*ping seconds
                         * and it has a ping time, then close its connection.
                         */
                        if(((CurrentTime - client_p->localClient->lasttime) >= (2 * ping)
                            && (client_p->flags & FLAGS_PINGSENT)))
                        {
                                if(IsServer(client_p))
                                {
                                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                             "No response from %s, closing link",
                                                             get_server_name(client_p, HIDE_IP));
                                        ilog(L_SERVER,
                                             "No response from %s, closing link",
                                             log_client_name(client_p, HIDE_IP));
                                }
                                (void) ircsnprintf(scratch, sizeof(scratch),
                                                  "Ping timeout: %d seconds",
                                                  (int) (CurrentTime - client_p->localClient->lasttime));

                                exit_client(client_p, client_p, &me, scratch);
                                continue;
                        }
                        else if((client_p->flags & FLAGS_PINGSENT) == 0)
                        {
                                /*
                                 * if we havent PINGed the connection and we havent
                                 * heard from it in a while, PING it to make sure
                                 * it is still alive.
                                 */
                                client_p->flags |= FLAGS_PINGSENT;
                                /* not nice but does the job */
                                client_p->localClient->lasttime = CurrentTime - ping;
                                sendto_one(client_p, "PING :%s", me.name);
                        }
                }
                /* ping_timeout: */

        }
}

/*
 * check_unknowns_list
 *
 * inputs       - pointer to list of unknown clients
 * output       - NONE
 * side effects - unknown clients get marked for termination after n seconds
 */
static void
check_unknowns_list(dlink_list * list)
{
        dlink_node *ptr, *next_ptr;
        struct Client *client_p;

        DLINK_FOREACH_SAFE(ptr, next_ptr, list->head)
        {
                client_p = ptr->data;

                if(IsDead(client_p) || IsClosing(client_p))
                        continue;

                /*
                 * Check UNKNOWN connections - if they have been in this state
                 * for > 30s, close them.
                 */

                if((CurrentTime - client_p->localClient->firsttime) > 30)
                        exit_client(client_p, client_p, &me, "Connection timed out");
        }
}

static void
notify_banned_client(struct Client *client_p, struct ConfItem *aconf, int ban)
{
        static const char conn_closed[] = "Connection closed";
        static const char d_lined[] = "D-lined";
        static const char k_lined[] = "K-lined";
        static const char g_lined[] = "G-lined";
        const char *reason = NULL;
        const char *exit_reason = conn_closed;

        if(ConfigFileEntry.kline_with_reason && !EmptyString(aconf->passwd))
        {
                reason = aconf->passwd;
                exit_reason = aconf->passwd;
        }
        else
        {
                switch (aconf->status)
                {
                case D_LINED:
                        reason = d_lined;
                        break;
                case G_LINED:
                        reason = g_lined;
                        break;
                default:
                        reason = k_lined;
                        break;
                }
        }

        if(ban == D_LINED && !IsPerson(client_p))
                sendto_one(client_p, "NOTICE DLINE :*** You have been D-lined");
        else
                sendto_one(client_p, form_str(ERR_YOUREBANNEDCREEP),
                           me.name, client_p->name, reason);
        
        exit_client(client_p, client_p, &me, 
                        EmptyString(ConfigFileEntry.kline_reason) ? exit_reason :
                         ConfigFileEntry.kline_reason);
}

/*
 * check_banned_lines
 * inputs       - NONE
 * output       - NONE
 * side effects - Check all connections for a pending k/d/gline against the
 *                client, exit the client if found.
 */
void
check_banned_lines(void)
{
        struct Client *client_p;        /* current local client_p being examined */
        struct ConfItem *aconf = NULL;
        dlink_node *ptr, *next_ptr;

        DLINK_FOREACH_SAFE(ptr, next_ptr, lclient_list.head)
        {
                client_p = ptr->data;

                if(IsMe(client_p))
                        continue;

                /* if there is a returned struct ConfItem then kill it */
                if((aconf = find_dline((struct sockaddr *)&client_p->localClient->ip, client_p->localClient->ip.ss_family)))
                {
                        if(aconf->status & CONF_EXEMPTDLINE)
                                continue;

                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "DLINE active for %s",
                                             get_client_name(client_p, HIDE_IP));

                        notify_banned_client(client_p, aconf, D_LINED);
                        continue;       /* and go examine next fd/client_p */
                }

                if(!IsPerson(client_p))
                        continue;

                if((aconf = find_kline(client_p)) != NULL)
                {
                        if(IsExemptKline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                "KLINE over-ruled for %s, client is kline_exempt [%s@%s]",
                                                get_client_name(client_p, HIDE_IP),
                                                aconf->user, aconf->host);
                                continue;
                        }

                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                        "KLINE active for %s",
                                        get_client_name(client_p, HIDE_IP));
                        notify_banned_client(client_p, aconf, K_LINED);
                        continue;
                }
                else if((aconf = find_gline(client_p)) != NULL)
                {
                        if(IsExemptKline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                "GLINE over-ruled for %s, client is kline_exempt [%s@%s]",
                                                get_client_name(client_p, HIDE_IP),
                                                aconf->user, aconf->host);
                                continue;
                        }

                        if(IsExemptGline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                "GLINE over-ruled for %s, client is gline_exempt [%s@%s]",
                                                get_client_name(client_p, HIDE_IP),
                                                aconf->user, aconf->host);
                                continue;
                        }

                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                        "GLINE active for %s",
                                        get_client_name(client_p, HIDE_IP));

                        notify_banned_client(client_p, aconf, G_LINED);
                        continue;
                }
                else if((aconf = find_xline(client_p->info, 1)) != NULL)
                {
                        if(IsExemptKline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                "XLINE over-ruled for %s, client is kline_exempt [%s]",
                                                get_client_name(client_p, HIDE_IP),
                                                aconf->name);
                                continue;
                        }

                        sendto_realops_snomask(SNO_GENERAL, L_ALL, "XLINE active for %s",
                                        get_client_name(client_p, HIDE_IP));

                        (void) exit_client(client_p, client_p, &me, "Bad user info");
                        continue;
                }
        }

        /* also check the unknowns list for new dlines */
        DLINK_FOREACH_SAFE(ptr, next_ptr, unknown_list.head)
        {
                client_p = ptr->data;

                if((aconf = find_dline((struct sockaddr *)&client_p->localClient->ip,client_p->localClient->ip.ss_family)))
                {
                        if(aconf->status & CONF_EXEMPTDLINE)
                                continue;

                        notify_banned_client(client_p, aconf, D_LINED);
                }
        }

}

/* check_klines_event()
 *
 * inputs       -
 * outputs      -
 * side effects - check_klines() is called, kline_queued unset
 */
void
check_klines_event(void *unused)
{
        kline_queued = 0;
        check_klines();
}

/* check_klines
 *
 * inputs       -
 * outputs      -
 * side effects - all clients will be checked for klines
 */
void
check_klines(void)
{
        struct Client *client_p;
        struct ConfItem *aconf;
        dlink_node *ptr;
        dlink_node *next_ptr;

        DLINK_FOREACH_SAFE(ptr, next_ptr, lclient_list.head)
        {
                client_p = ptr->data;

                if(IsMe(client_p) || !IsPerson(client_p))
                        continue;

                if((aconf = find_kline(client_p)) != NULL)
                {
                        if(IsExemptKline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                     "KLINE over-ruled for %s, client is kline_exempt",
                                                     get_client_name(client_p, HIDE_IP));
                                continue;
                        }

                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "KLINE active for %s",
                                             get_client_name(client_p, HIDE_IP));

                        notify_banned_client(client_p, aconf, K_LINED);
                        continue;
                }
        }
}

/* check_glines()
 *
 * inputs       -
 * outputs      -
 * side effects - all clients will be checked for glines
 */
void
check_glines(void)
{
        struct Client *client_p;
        struct ConfItem *aconf;
        dlink_node *ptr;
        dlink_node *next_ptr;

        DLINK_FOREACH_SAFE(ptr, next_ptr, lclient_list.head)
        {
                client_p = ptr->data;

                if(IsMe(client_p) || !IsPerson(client_p))
                        continue;

                if((aconf = find_gline(client_p)) != NULL)
                {
                        if(IsExemptKline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                     "GLINE over-ruled for %s, client is kline_exempt",
                                                     get_client_name(client_p, HIDE_IP));
                                continue;
                        }

                        if(IsExemptGline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                     "GLINE over-ruled for %s, client is gline_exempt",
                                                     get_client_name(client_p, HIDE_IP));
                                continue;
                        }

                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "GLINE active for %s",
                                             get_client_name(client_p, HIDE_IP));

                        notify_banned_client(client_p, aconf, K_LINED);
                        continue;
                }
        }
}

/* check_dlines()
 *
 * inputs       -
 * outputs      -
 * side effects - all clients will be checked for dlines
 */
void
check_dlines(void)
{
        struct Client *client_p;
        struct ConfItem *aconf;
        dlink_node *ptr;
        dlink_node *next_ptr;

        DLINK_FOREACH_SAFE(ptr, next_ptr, lclient_list.head)
        {
                client_p = ptr->data;

                if(IsMe(client_p))
                        continue;

                if((aconf = find_dline((struct sockaddr *)&client_p->localClient->ip,client_p->localClient->ip.ss_family)) != NULL)
                {
                        if(aconf->status & CONF_EXEMPTDLINE)
                                continue;

                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "DLINE active for %s",
                                             get_client_name(client_p, HIDE_IP));

                        notify_banned_client(client_p, aconf, D_LINED);
                        continue;
                }
        }

        /* dlines need to be checked against unknowns too */
        DLINK_FOREACH_SAFE(ptr, next_ptr, unknown_list.head)
        {
                client_p = ptr->data;

                if((aconf = find_dline((struct sockaddr *)&client_p->localClient->ip,client_p->localClient->ip.ss_family)) != NULL)
                {
                        if(aconf->status & CONF_EXEMPTDLINE)
                                continue;

                        notify_banned_client(client_p, aconf, D_LINED);
                }
        }
}

/* check_xlines
 *
 * inputs       -
 * outputs      -
 * side effects - all clients will be checked for xlines
 */
void
check_xlines(void)
{
        struct Client *client_p;
        struct ConfItem *aconf;
        dlink_node *ptr;
        dlink_node *next_ptr;

        DLINK_FOREACH_SAFE(ptr, next_ptr, lclient_list.head)
        {
                client_p = ptr->data;

                if(IsMe(client_p) || !IsPerson(client_p))
                        continue;

                if((aconf = find_xline(client_p->info, 1)) != NULL)
                {
                        if(IsExemptKline(client_p))
                        {
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                     "XLINE over-ruled for %s, client is kline_exempt",
                                                     get_client_name(client_p, HIDE_IP));
                                continue;
                        }

                        sendto_realops_snomask(SNO_GENERAL, L_ALL, "XLINE active for %s",
                                             get_client_name(client_p, HIDE_IP));

                        (void) exit_client(client_p, client_p, &me, "Bad user info");
                        continue;
                }
        }
}

/*
 * update_client_exit_stats
 *
 * input        - pointer to client
 * output       - NONE
 * side effects - 
 */
static void
update_client_exit_stats(struct Client *client_p)
{
        if(IsServer(client_p))
        {
                sendto_realops_snomask(SNO_EXTERNAL, L_ALL,
                                     "Server %s split from %s",
                                     client_p->name, client_p->servptr->name);
                if(HasSentEob(client_p))
                        eob_count--;
        }
        else if(IsClient(client_p))
        {
                --Count.total;
                if(IsOper(client_p))
                        --Count.oper;
                if(IsInvisible(client_p))
                        --Count.invisi;
        }

        if(splitchecking && !splitmode)
                check_splitmode(NULL);
}

/*
 * release_client_state
 *
 * input        - pointer to client to release
 * output       - NONE
 * side effects - 
 */
static void
release_client_state(struct Client *client_p)
{
        if(client_p->user != NULL)
        {
                free_user(client_p->user, client_p);    /* try this here */
        }
        if(client_p->serv)
        {
                if(client_p->serv->user != NULL)
                        free_user(client_p->serv->user, client_p);
                if(client_p->serv->fullcaps)
                        MyFree(client_p->serv->fullcaps);
                MyFree(client_p->serv);
        }
}

/*
 * remove_client_from_list
 * inputs       - point to client to remove
 * output       - NONE
 * side effects - taken the code from ExitOneClient() for this
 *                and placed it here. - avalon
 */
static void
remove_client_from_list(struct Client *client_p)
{
        s_assert(NULL != client_p);

        if(client_p == NULL)
                return;

        /* A client made with make_client()
         * is on the unknown_list until removed.
         * If it =does= happen to exit before its removed from that list
         * and its =not= on the global_client_list, it will core here.
         * short circuit that case now -db
         */
        if(client_p->node.prev == NULL && client_p->node.next == NULL)
                return;

        dlinkDelete(&client_p->node, &global_client_list);

        update_client_exit_stats(client_p);
}


/*
 * find_person  - find person by (nick)name.
 * inputs       - pointer to name
 * output       - return client pointer
 * side effects -
 */
struct Client *
find_person(const char *name)
{
        struct Client *c2ptr;

        c2ptr = find_client(name);

        if(c2ptr && IsPerson(c2ptr))
                return (c2ptr);
        return (NULL);
}

struct Client *
find_named_person(const char *name)
{
        struct Client *c2ptr;

        c2ptr = find_named_client(name);

        if(c2ptr && IsPerson(c2ptr))
                return (c2ptr);
        return (NULL);
}


/*
 * find_chasing - find the client structure for a nick name (user) 
 *      using history mechanism if necessary. If the client is not found, 
 *      an error message (NO SUCH NICK) is generated. If the client was found
 *      through the history, chasing will be 1 and otherwise 0.
 */
struct Client *
find_chasing(struct Client *source_p, const char *user, int *chasing)
{
        struct Client *who;

        if(MyClient(source_p))
                who = find_named_person(user);
        else
                who = find_person(user);

        if(chasing)
                *chasing = 0;

        if(who || IsDigit(*user))
                return who;

        if(!(who = get_history(user, (long) KILLCHASETIMELIMIT)))
        {
                sendto_one_numeric(source_p, ERR_NOSUCHNICK,
                                   form_str(ERR_NOSUCHNICK), user);
                return (NULL);
        }
        if(chasing)
                *chasing = 1;
        return who;
}

/*
 * get_client_name -  Return the name of the client
 *    for various tracking and
 *      admin purposes. The main purpose of this function is to
 *      return the "socket host" name of the client, if that
 *        differs from the advertised name (other than case).
 *        But, this can be used to any client structure.
 *
 * NOTE 1:
 *        Watch out the allocation of "nbuf", if either source_p->name
 *        or source_p->sockhost gets changed into pointers instead of
 *        directly allocated within the structure...
 *
 * NOTE 2:
 *        Function return either a pointer to the structure (source_p) or
 *        to internal buffer (nbuf). *NEVER* use the returned pointer
 *        to modify what it points!!!
 */

const char *
get_client_name(struct Client *client, int showip)
{
        static char nbuf[HOSTLEN * 2 + USERLEN + 5];

        s_assert(NULL != client);
        if(client == NULL)
                return NULL;

        if(MyConnect(client))
        {
                if(!irccmp(client->name, client->host))
                        return client->name;

                if(ConfigFileEntry.hide_spoof_ips && 
                   showip == SHOW_IP && IsIPSpoof(client))
                        showip = MASK_IP;
#ifdef HIDE_SERVERS_IPS
                if(IsAnyServer(client))
                        showip = MASK_IP;
#endif

                /* And finally, let's get the host information, ip or name */
                switch (showip)
                {
                case SHOW_IP:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@%s]", 
                                   client->name, client->username, 
                                   client->sockhost);
                        break;
                case MASK_IP:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@255.255.255.255]",
                                   client->name, client->username);
                        break;
                default:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@%s]",
                                   client->name, client->username, client->host);
                }
                return nbuf;
        }

        /* As pointed out by Adel Mezibra 
         * Neph|l|m@EFnet. Was missing a return here.
         */
        return client->name;
}

const char *
get_server_name(struct Client *target_p, int showip)
{
        static char nbuf[HOSTLEN * 2 + USERLEN + 5];

        if(target_p == NULL)
                return NULL;

        if(!MyConnect(target_p) || !irccmp(target_p->name, target_p->host))
                return target_p->name;

#ifdef HIDE_SERVERS_IPS
        if(EmptyString(target_p->name))
        {
                ircsnprintf(nbuf, sizeof(nbuf), "[%s@255.255.255.255]",
                                target_p->username);
                return nbuf;
        }
        else
                return target_p->name;
#endif

        switch (showip)
        {
                case SHOW_IP:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@%s]",
                                target_p->name, target_p->username, 
                                target_p->sockhost);
                        break;

                case MASK_IP:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@255.255.255.255]",
                                target_p->name, target_p->username);

                default:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@%s]",
                                target_p->name, target_p->username,
                                target_p->host);
        }

        return nbuf;
}
        
/* log_client_name()
 *
 * This version is the same as get_client_name, but doesnt contain the
 * code that will hide IPs always.  This should be used for logfiles.
 */
const char *
log_client_name(struct Client *target_p, int showip)
{
        static char nbuf[HOSTLEN * 2 + USERLEN + 5];

        if(target_p == NULL)
                return NULL;

        if(MyConnect(target_p))
        {
                if(irccmp(target_p->name, target_p->host) == 0)
                        return target_p->name;

                switch (showip)
                {
                case SHOW_IP:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@%s]", target_p->name,
                                   target_p->username, target_p->sockhost);
                        break;

                case MASK_IP:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@255.255.255.255]",
                                   target_p->name, target_p->username);

                default:
                        ircsnprintf(nbuf, sizeof(nbuf), "%s[%s@%s]", target_p->name,
                                   target_p->username, target_p->host);
                }

                return nbuf;
        }

        return target_p->name;
}

/* is_remote_connect - Returns whether a server was /connect'ed by a remote
 * oper (send notices netwide) */
int
is_remote_connect(struct Client *client_p)
{
        struct Client *oper;

        if (client_p->serv == NULL)
                return FALSE;
        oper = find_named_person(client_p->serv->by);
        return oper != NULL && IsOper(oper) && !MyConnect(oper);
}

static void
free_exited_clients(void *unused)
{
        dlink_node *ptr, *next;
        struct Client *target_p;

        DLINK_FOREACH_SAFE(ptr, next, dead_list.head)
        {
                target_p = ptr->data;

#ifdef DEBUG_EXITED_CLIENTS
                {
                        struct abort_client *abt;
                        dlink_node *aptr;
                        int found = 0;

                        DLINK_FOREACH(aptr, abort_list.head)
                        {
                                abt = aptr->data;
                                if(abt->client == target_p)
                                {
                                        s_assert(0);
                                        sendto_realops_snomask(SNO_GENERAL, L_ALL, 
                                                "On abort_list: %s stat: %u flags: %u/%u handler: %c",
                                                target_p->name, (unsigned int) target_p->status,
                                                target_p->flags, target_p->flags2, target_p->handler);
                                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                                "Please report this to the charybdis developers!");
                                        found++;
                                }
                        }

                        if(found)
                        {
                                dlinkDestroy(ptr, &dead_list);
                                continue;
                        }
                }
#endif

                if(ptr->data == NULL)
                {
                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "Warning: null client on dead_list!");
                        dlinkDestroy(ptr, &dead_list);
                        continue;
                }
                release_client_state(target_p);
                free_client(target_p);
                dlinkDestroy(ptr, &dead_list);
        }

#ifdef DEBUG_EXITED_CLIENTS
        DLINK_FOREACH_SAFE(ptr, next, dead_remote_list.head)
        {
                target_p = ptr->data;

                if(ptr->data == NULL)
                {
                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "Warning: null client on dead_list!");
                        dlinkDestroy(ptr, &dead_list);
                        continue;
                }
                release_client_state(target_p);
                free_client(target_p);
                dlinkDestroy(ptr, &dead_remote_list);
        }
#endif
        
}

/*
** Recursively send QUITs and SQUITs for source_p and all its dependent clients
** and servers to those servers that need them.  A server needs the client
** QUITs if it can't figure them out from the SQUIT (ie pre-TS4) or if it
** isn't getting the SQUIT because of @#(*&@)# hostmasking.  With TS4, once
** a link gets a SQUIT, it doesn't need any QUIT/SQUITs for clients depending
** on that one -orabidoo
*/
static void
recurse_send_quits(struct Client *client_p, struct Client *source_p, 
                   struct Client *to, const char *comment1,
                   const char *comment)
{
        struct Client *target_p;
        dlink_node *ptr, *ptr_next;
        /* If this server can handle quit storm (QS) removal
         * of dependents, just send the SQUIT
         */

        if(IsCapable(to, CAP_QS))
        {
                sendto_one(to, "SQUIT %s :%s",
                           get_id(source_p, to), comment);
        }
        else
        {
                DLINK_FOREACH_SAFE(ptr, ptr_next, source_p->serv->users.head)
                {
                        target_p = ptr->data;
                        sendto_one(to, ":%s QUIT :%s", target_p->name, comment1);
                }
                DLINK_FOREACH_SAFE(ptr, ptr_next, source_p->serv->servers.head)
                {
                        target_p = ptr->data;
                        recurse_send_quits(client_p, target_p, to, comment1, comment);
                }
                sendto_one(to, "SQUIT %s :%s", source_p->name, comment);
        }
}

/* 
** Remove all clients that depend on source_p; assumes all (S)QUITs have
** already been sent.  we make sure to exit a server's dependent clients 
** and servers before the server itself; exit_one_client takes care of 
** actually removing things off llists.   tweaked from +CSr31  -orabidoo
*/
/*
 * added sanity test code.... source_p->serv might be NULL...
 */
static void
recurse_remove_clients(struct Client *source_p, const char *comment)
{
        struct Client *target_p;
        dlink_node *ptr, *ptr_next;

        if(IsMe(source_p))
                return;

        if(source_p->serv == NULL)      /* oooops. uh this is actually a major bug */
                return;

        /* this is very ugly, but it saves cpu :P */
        if(ConfigFileEntry.nick_delay > 0)
        {
                DLINK_FOREACH_SAFE(ptr, ptr_next, source_p->serv->users.head)
                {
                        target_p = ptr->data;
                        target_p->flags |= FLAGS_KILLED;
                        add_nd_entry(target_p->name);

                        if(!IsDead(target_p) && !IsClosing(target_p))
                                exit_remote_client(NULL, target_p, &me, comment);
                }
        }
        else
        {
                DLINK_FOREACH_SAFE(ptr, ptr_next, source_p->serv->users.head)
                {
                        target_p = ptr->data;
                        target_p->flags |= FLAGS_KILLED;

                        if(!IsDead(target_p) && !IsClosing(target_p))
                                exit_remote_client(NULL, target_p, &me, comment);
                }
        }       

        DLINK_FOREACH_SAFE(ptr, ptr_next, source_p->serv->servers.head)
        {
                target_p = ptr->data;
                recurse_remove_clients(target_p, comment);
                qs_server(NULL, target_p, &me, comment);
        }
}

/*
** Remove *everything* that depends on source_p, from all lists, and sending
** all necessary QUITs and SQUITs.  source_p itself is still on the lists,
** and its SQUITs have been sent except for the upstream one  -orabidoo
*/
static void
remove_dependents(struct Client *client_p,
                  struct Client *source_p,
                  struct Client *from, const char *comment, const char *comment1)
{
        struct Client *to;
        dlink_node *ptr, *next;

        DLINK_FOREACH_SAFE(ptr, next, serv_list.head)
        {
                to = ptr->data;

                if(IsMe(to) || to == source_p->from || 
                   (to == client_p && IsCapable(to, CAP_QS)))
                        continue;

                recurse_send_quits(client_p, source_p, to, comment1, comment);
        }

        recurse_remove_clients(source_p, comment1);
}

void
exit_aborted_clients(void *unused)
{
        struct abort_client *abt;
        dlink_node *ptr, *next;
        DLINK_FOREACH_SAFE(ptr, next, abort_list.head)
        {
                abt = ptr->data;

#ifdef DEBUG_EXITED_CLIENTS
                {
                        if(dlinkFind(abt->client, &dead_list))
                        {
                                s_assert(0);
                                sendto_realops_snomask(SNO_GENERAL, L_ALL, 
                                        "On dead_list: %s stat: %u flags: %u/%u handler: %c",
                                        abt->client->name, (unsigned int) abt->client->status,
                                        abt->client->flags, abt->client->flags2, abt->client->handler);
                                sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                        "Please report this to the charybdis developers!");
                                continue;
                        }
                }
#endif

                s_assert(*((unsigned long*)abt->client) != 0xdeadbeef); /* This is lame but its a debug thing */
                dlinkDelete(ptr, &abort_list);

                if(IsAnyServer(abt->client))
                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "Closing link to %s: %s",
                                             get_server_name(abt->client, HIDE_IP), abt->notice);

                /* its no longer on abort list - we *must* remove
                 * FLAGS_CLOSING otherwise exit_client() will not run --fl
                 */
                abt->client->flags &= ~FLAGS_CLOSING;
                exit_client(abt->client, abt->client, &me, abt->notice);
                MyFree(abt);
        }
}


/*
 * dead_link - Adds client to a list of clients that need an exit_client()
 *
 */
void
dead_link(struct Client *client_p)
{
        struct abort_client *abt;

        s_assert(!IsMe(client_p));
        if(IsDead(client_p) || IsClosing(client_p) || IsMe(client_p))
                return;

        abt = (struct abort_client *) MyMalloc(sizeof(struct abort_client));

        if(client_p->flags & FLAGS_SENDQEX)
                strlcpy(abt->notice, "Max SendQ exceeded", sizeof(abt->notice));
        else
                ircsnprintf(abt->notice, sizeof(abt->notice), "Write error: %s", strerror(errno));

        abt->client = client_p;
        SetIOError(client_p);
        SetDead(client_p);
        SetClosing(client_p);
        dlinkAdd(abt, &abt->node, &abort_list);
}


/* This does the remove of the user from channels..local or remote */
static inline void
exit_generic_client(struct Client *client_p, struct Client *source_p, struct Client *from,
                   const char *comment)
{
        dlink_node *ptr, *next_ptr;

        if(IsOper(source_p))
                dlinkFindDestroy(source_p, &oper_list);

        sendto_common_channels_local(source_p, ":%s!%s@%s QUIT :%s",
                                     source_p->name,
                                     source_p->username, source_p->host, comment);

        remove_user_from_channels(source_p);

        /* Should not be in any channels now */
        s_assert(source_p->user->channel.head == NULL);

        /* Clean up invitefield */
        DLINK_FOREACH_SAFE(ptr, next_ptr, source_p->user->invited.head)
        {
                del_invite(ptr->data, source_p);
        }

        /* Clean up allow lists */
        del_all_accepts(source_p);

        add_history(source_p, 0);
        off_history(source_p);

        monitor_signoff(source_p);

        if(has_id(source_p))
                del_from_id_hash(source_p->id, source_p);

        del_from_hostname_hash(source_p->orighost, source_p);
        del_from_client_hash(source_p->name, source_p);
        remove_client_from_list(source_p);
}

/* 
 * Assumes IsPerson(source_p) && !MyConnect(source_p)
 */

static int
exit_remote_client(struct Client *client_p, struct Client *source_p, struct Client *from,
                   const char *comment)
{
        exit_generic_client(client_p, source_p, from, comment);
        
        if(source_p->servptr && source_p->servptr->serv)
        {
                dlinkDelete(&source_p->lnode, &source_p->servptr->serv->users);
        }

        if((source_p->flags & FLAGS_KILLED) == 0)
        {
                sendto_server(client_p, NULL, CAP_TS6, NOCAPS,
                              ":%s QUIT :%s", use_id(source_p), comment);
                sendto_server(client_p, NULL, NOCAPS, CAP_TS6,
                              ":%s QUIT :%s", source_p->name, comment);
        }

        SetDead(source_p);
#ifdef DEBUG_EXITED_CLIENTS
        dlinkAddAlloc(source_p, &dead_remote_list);
#else
        dlinkAddAlloc(source_p, &dead_list);
#endif
        return(CLIENT_EXITED);
}

/*
 * This assumes IsUnknown(source_p) == TRUE and MyConnect(source_p) == TRUE
 */

static int
exit_unknown_client(struct Client *client_p, struct Client *source_p, struct Client *from,
                  const char *comment)
{
        delete_auth_queries(source_p);
        client_flush_input(source_p);
        del_unknown_ip(source_p);
        dlinkDelete(&source_p->localClient->tnode, &unknown_list);

        if(!IsIOError(source_p))
                sendto_one(source_p, "ERROR :Closing Link: %s (%s)",
                        source_p->user != NULL ? source_p->host : "127.0.0.1",
                        comment);

        close_connection(source_p);

        if(has_id(source_p))
                del_from_id_hash(source_p->id, source_p);

        del_from_hostname_hash(source_p->host, source_p);
        del_from_client_hash(source_p->name, source_p);
        remove_client_from_list(source_p);
        SetDead(source_p);
        dlinkAddAlloc(source_p, &dead_list);

        /* Note that we don't need to add unknowns to the dead_list */
        return(CLIENT_EXITED);
}

static int
exit_remote_server(struct Client *client_p, struct Client *source_p, struct Client *from, 
                  const char *comment)
{
        static char comment1[(HOSTLEN*2)+2];
        static char newcomment[BUFSIZE];
        struct Client *target_p;
        
        if(ConfigServerHide.flatten_links)
                strcpy(comment1, "*.net *.split");
        else
        {
                strcpy(comment1, source_p->servptr->name);
                strcat(comment1, " ");
                strcat(comment1, source_p->name);
        }
        if (IsPerson(from))
                ircsnprintf(newcomment, sizeof(newcomment), "by %s: %s",
                                from->name, comment);

        if(source_p->serv != NULL)
                remove_dependents(client_p, source_p, from, IsPerson(from) ? newcomment : comment, comment1);

        if(source_p->servptr && source_p->servptr->serv)
                dlinkDelete(&source_p->lnode, &source_p->servptr->serv->servers);
        else
                s_assert(0);

        dlinkFindDestroy(source_p, &global_serv_list);
        target_p = source_p->from;
        
        if(target_p != NULL && IsServer(target_p) && target_p != client_p &&
           !IsMe(target_p) && (source_p->flags & FLAGS_KILLED) == 0)
        {
                sendto_one(target_p, ":%s SQUIT %s :%s", 
                           get_id(from, target_p), get_id(source_p, target_p),
                           comment);
        }

        if(has_id(source_p))
                del_from_id_hash(source_p->id, source_p);

        del_from_client_hash(source_p->name, source_p);
        remove_client_from_list(source_p);  
        scache_split(source_p->serv->nameinfo);
        
        SetDead(source_p);
#ifdef DEBUG_EXITED_CLIENTS
        dlinkAddAlloc(source_p, &dead_remote_list);
#else
        dlinkAddAlloc(source_p, &dead_list);
#endif
        return 0;
}

static int
qs_server(struct Client *client_p, struct Client *source_p, struct Client *from, 
                  const char *comment)
{
        struct Client *target_p;

        if(source_p->servptr && source_p->servptr->serv)
                dlinkDelete(&source_p->lnode, &source_p->servptr->serv->servers);
        else
                s_assert(0);

        dlinkFindDestroy(source_p, &global_serv_list);
        target_p = source_p->from;
        
        if(has_id(source_p))
                del_from_id_hash(source_p->id, source_p);

        del_from_client_hash(source_p->name, source_p);
        remove_client_from_list(source_p);  
        
        SetDead(source_p);
        dlinkAddAlloc(source_p, &dead_list);    
        return 0;
}

static int
exit_local_server(struct Client *client_p, struct Client *source_p, struct Client *from, 
                  const char *comment)
{
        static char comment1[(HOSTLEN*2)+2];
        static char newcomment[BUFSIZE];
        unsigned int sendk, recvk;
        
        dlinkDelete(&source_p->localClient->tnode, &serv_list);
        dlinkFindDestroy(source_p, &global_serv_list);
        
        unset_chcap_usage_counts(source_p);
        sendk = source_p->localClient->sendK;
        recvk = source_p->localClient->receiveK;

        /* Always show source here, so the server notices show
         * which side initiated the split -- jilles
         */
        ircsnprintf(newcomment, sizeof(newcomment), "by %s: %s",
                        from == source_p ? me.name : from->name, comment);
        if (!IsIOError(source_p))
                sendto_one(source_p, "SQUIT %s :%s", use_id(source_p),
                                newcomment);
        if(client_p != NULL && source_p != client_p && !IsIOError(source_p))
        {
                sendto_one(source_p, "ERROR :Closing Link: 127.0.0.1 %s (%s)",
                           source_p->name, comment);
        }
        
        if(source_p->servptr && source_p->servptr->serv)
                dlinkDelete(&source_p->lnode, &source_p->servptr->serv->servers);
        else
                s_assert(0);


        close_connection(source_p);
        
        if(ConfigServerHide.flatten_links)
                strcpy(comment1, "*.net *.split");
        else
        {
                strcpy(comment1, source_p->servptr->name);
                strcat(comment1, " ");
                strcat(comment1, source_p->name);
        }

        if(source_p->serv != NULL)
                remove_dependents(client_p, source_p, from, IsPerson(from) ? newcomment : comment, comment1);

        sendto_realops_snomask(SNO_GENERAL, L_ALL, "%s was connected"
                             " for %ld seconds.  %d/%d sendK/recvK.",
                             source_p->name, CurrentTime - source_p->localClient->firsttime, sendk, recvk);

        ilog(L_SERVER, "%s was connected for %ld seconds.  %d/%d sendK/recvK.",
             source_p->name, CurrentTime - source_p->localClient->firsttime, sendk, recvk);
        
        if(has_id(source_p))
                del_from_id_hash(source_p->id, source_p);

        del_from_client_hash(source_p->name, source_p);
        remove_client_from_list(source_p);
        scache_split(source_p->serv->nameinfo);
        
        SetDead(source_p);
        dlinkAddAlloc(source_p, &dead_list);
        return 0;
}


/* 
 * This assumes IsPerson(source_p) == TRUE && MyConnect(source_p) == TRUE
 */

static int
exit_local_client(struct Client *client_p, struct Client *source_p, struct Client *from,
                  const char *comment)
{
        unsigned long on_for;

        exit_generic_client(client_p, source_p, from, comment);
        clear_monitor(source_p);

        s_assert(IsPerson(source_p));
        client_flush_input(source_p);
        dlinkDelete(&source_p->localClient->tnode, &lclient_list);
        dlinkDelete(&source_p->lnode, &me.serv->users);

        if(IsOper(source_p))
                dlinkFindDestroy(source_p, &local_oper_list);

        sendto_realops_snomask(SNO_CCONN, L_ALL,
                             "Client exiting: %s (%s@%s) [%s] [%s]",
                             source_p->name,
                             source_p->username, source_p->host, comment,
                             show_ip(NULL, source_p) ? source_p->sockhost : "255.255.255.255");

        sendto_realops_snomask(SNO_CCONNEXT, L_ALL,
                        "CLIEXIT %s %s %s %s 0 %s",
                        source_p->name, source_p->username, source_p->host,
                        show_ip(NULL, source_p) ? source_p->sockhost : "255.255.255.255",
                        comment);

        on_for = CurrentTime - source_p->localClient->firsttime;

        ilog(L_USER, "%s (%3lu:%02lu:%02lu): %s!%s@%s %d/%d",
                myctime(CurrentTime), on_for / 3600,
                (on_for % 3600) / 60, on_for % 60,
                source_p->name, source_p->username, source_p->host,
                source_p->localClient->sendK, source_p->localClient->receiveK);

        sendto_one(source_p, "ERROR :Closing Link: %s (%s)", source_p->host, comment);
        close_connection(source_p);

        if((source_p->flags & FLAGS_KILLED) == 0)
        {
                sendto_server(client_p, NULL, CAP_TS6, NOCAPS,
                              ":%s QUIT :%s", use_id(source_p), comment);
                sendto_server(client_p, NULL, NOCAPS, CAP_TS6,
                              ":%s QUIT :%s", source_p->name, comment);
        }

        SetDead(source_p);
        dlinkAddAlloc(source_p, &dead_list);
        return(CLIENT_EXITED);
}


/*
** exit_client - This is old "m_bye". Name  changed, because this is not a
**        protocol function, but a general server utility function.
**
**        This function exits a client of *any* type (user, server, etc)
**        from this server. Also, this generates all necessary prototol
**        messages that this exit may cause.
**
**   1) If the client is a local client, then this implicitly
**        exits all other clients depending on this connection (e.g.
**        remote clients having 'from'-field that points to this.
**
**   2) If the client is a remote client, then only this is exited.
**
** For convenience, this function returns a suitable value for
** m_function return value:
**
**        CLIENT_EXITED        if (client_p == source_p)
**        0                if (client_p != source_p)
*/
int
exit_client(struct Client *client_p,    /* The local client originating the
                                         * exit or NULL, if this exit is
                                         * generated by this server for
                                         * internal reasons.
                                         * This will not get any of the
                                         * generated messages. */
            struct Client *source_p,    /* Client exiting */
            struct Client *from,        /* Client firing off this Exit,
                                         * never NULL! */
            const char *comment /* Reason for the exit */
        )
{
        hook_data_client_exit hdata;
        if(IsClosing(source_p))
                return -1;

        /* note, this HAS to be here, when we exit a client we attempt to
         * send them data, if this generates a write error we must *not* add
         * them to the abort list --fl
         */
        SetClosing(source_p);

        hdata.local_link = client_p;
        hdata.target = source_p;
        hdata.from = from;
        hdata.comment = comment;
        call_hook(h_client_exit, &hdata);

        if(MyConnect(source_p))
        {
                /* Local clients of various types */
                if(IsPerson(source_p))
                        return exit_local_client(client_p, source_p, from, comment);
                else if(IsServer(source_p))
                        return exit_local_server(client_p, source_p, from, comment);
                /* IsUnknown || IsConnecting || IsHandShake */
                else if(!IsReject(source_p))
                        return exit_unknown_client(client_p, source_p, from, comment);
        } 
        else 
        {
                /* Remotes */
                if(IsPerson(source_p))
                        return exit_remote_client(client_p, source_p, from, comment);
                else if(IsServer(source_p))
                        return exit_remote_server(client_p, source_p, from, comment);
        }

        return -1;
}

/*
 * Count up local client memory
 */

/* XXX one common Client list now */
void
count_local_client_memory(size_t * count, size_t * local_client_memory_used)
{
        size_t lusage;
        BlockHeapUsage(lclient_heap, count, NULL, &lusage);
        *local_client_memory_used = lusage + (*count * (sizeof(MemBlock) + sizeof(struct Client)));
}

/*
 * Count up remote client memory
 */
void
count_remote_client_memory(size_t * count, size_t * remote_client_memory_used)
{
        size_t lcount, rcount;
        BlockHeapUsage(lclient_heap, &lcount, NULL, NULL);
        BlockHeapUsage(client_heap, &rcount, NULL, NULL);
        *count = rcount - lcount;
        *remote_client_memory_used = *count * (sizeof(MemBlock) + sizeof(struct Client));
}


/*
 * accept processing, this adds a form of "caller ID" to ircd
 * 
 * If a client puts themselves into "caller ID only" mode,
 * only clients that match a client pointer they have put on 
 * the accept list will be allowed to message them.
 *
 * [ source.on_allow_list ] -> [ target1 ] -> [ target2 ]
 *
 * [target.allow_list] -> [ source1 ] -> [source2 ]
 *
 * i.e. a target will have a link list of source pointers it will allow
 * each source client then has a back pointer pointing back
 * to the client that has it on its accept list.
 * This allows for exit_one_client to remove these now bogus entries
 * from any client having an accept on them. 
 */
/*
 * del_all_accepts
 *
 * inputs       - pointer to exiting client
 * output       - NONE
 * side effects - Walk through given clients allow_list and on_allow_list
 *                remove all references to this client
 */
void
del_all_accepts(struct Client *client_p)
{
        dlink_node *ptr;
        dlink_node *next_ptr;
        struct Client *target_p;

        if(MyClient(client_p) && client_p->localClient->allow_list.head)
        {
                /* clear this clients accept list, and remove them from
                 * everyones on_accept_list
                 */
                DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->localClient->allow_list.head)
                {
                        target_p = ptr->data;
                        dlinkFindDestroy(client_p, &target_p->on_allow_list);
                        dlinkDestroy(ptr, &client_p->localClient->allow_list);
                }
        }

        /* remove this client from everyones accept list */
        DLINK_FOREACH_SAFE(ptr, next_ptr, client_p->on_allow_list.head)
        {
                target_p = ptr->data;
                dlinkFindDestroy(client_p, &target_p->localClient->allow_list);
                dlinkDestroy(ptr, &client_p->on_allow_list);
        }
}

/*
 * show_ip() - asks if the true IP shoudl be shown when source is
 *             askin for info about target 
 *
 * Inputs       - source_p who is asking
 *              - target_p who do we want the info on
 * Output       - returns 1 if clear IP can be showed, otherwise 0
 * Side Effects - none
 */

int
show_ip(struct Client *source_p, struct Client *target_p)
{
        if(IsAnyServer(target_p))
        {
#ifndef HIDE_SERVERS_IPS
                if(source_p == NULL || IsOper(source_p))
                        return 1;
#endif
                return 0;
        }
        else if(IsIPSpoof(target_p))
        {
                /* source == NULL indicates message is being sent
                 * to local opers.
                 */
                if(!ConfigFileEntry.hide_spoof_ips &&
                   (source_p == NULL || MyOper(source_p)))
                        return 1;
                return 0;
        }
        else if(IsDynSpoof(target_p) && (source_p != NULL && !IsOper(source_p)))
                return 0;
        else
                return 1;
}

int
show_ip_conf(struct ConfItem *aconf, struct Client *source_p)
{
        if(IsConfDoSpoofIp(aconf))
        {
                if(!ConfigFileEntry.hide_spoof_ips && MyOper(source_p))
                        return 1;

                return 0;
        }
        else
                return 1;
}

/*
 * initUser
 *
 * inputs       - none
 * outputs      - none
 *
 * side effects - Creates a block heap for struct Users
 *
 */
static BlockHeap *user_heap;
void
initUser(void)
{
        user_heap = BlockHeapCreate(sizeof(struct User), USER_HEAP_SIZE);
        if(!user_heap)
                outofmemory();
}

/*
 * make_user
 *
 * inputs       - pointer to client struct
 * output       - pointer to struct User
 * side effects - add's an User information block to a client
 *                if it was not previously allocated.
 */
struct User *
make_user(struct Client *client_p)
{
        struct User *user;

        user = client_p->user;
        if(!user)
        {
                user = (struct User *) BlockHeapAlloc(user_heap);
                user->refcnt = 1;
                client_p->user = user;
        }
        return user;
}

/*
 * make_server
 *
 * inputs       - pointer to client struct
 * output       - pointer to server_t
 * side effects - add's an Server information block to a client
 *                if it was not previously allocated.
 */
server_t *
make_server(struct Client *client_p)
{
        server_t *serv = client_p->serv;

        if(!serv)
        {
                serv = (server_t *) MyMalloc(sizeof(server_t));
                client_p->serv = serv;
        }
        return client_p->serv;
}

/*
 * free_user
 * 
 * inputs       - pointer to user struct
 *              - pointer to client struct
 * output       - none
 * side effects - Decrease user reference count by one and release block,
 *                if count reaches 0
 */
void
free_user(struct User *user, struct Client *client_p)
{
        if(--user->refcnt <= 0)
        {
                if(user->away)
                        MyFree((char *) user->away);
                /*
                 * sanity check
                 */
                if(user->refcnt < 0 || user->invited.head || user->channel.head)
                {
                        sendto_realops_snomask(SNO_GENERAL, L_ALL,
                                             "* %#lx user (%s!%s@%s) %#lx %#lx %#lx %lu %d *",
                                             (unsigned long) client_p,
                                             client_p ? client_p->
                                             name : "<noname>",
                                             client_p->username,
                                             client_p->host,
                                             (unsigned long) user,
                                             (unsigned long) user->invited.head,
                                             (unsigned long) user->channel.head, 
                                             dlink_list_length(&user->channel),
                                             user->refcnt);
                        s_assert(!user->refcnt);
                        s_assert(!user->invited.head);
                        s_assert(!user->channel.head);
                }

                BlockHeapFree(user_heap, user);
        }
}

void
init_uid(void)
{
        int i;

        for(i = 0; i < 3; i++)
                current_uid[i] = me.id[i];

        for(i = 3; i < 9; i++)
                current_uid[i] = 'A';

        current_uid[9] = '\0';
}


char *
generate_uid(void)
{
        int i;

        for(i = 8; i > 3; i--)
        {
                if(current_uid[i] == 'Z')
                {
                        current_uid[i] = '0';
                        return current_uid;
                }
                else if(current_uid[i] != '9')
                {
                        current_uid[i]++;
                        return current_uid;
                }
                else
                        current_uid[i] = 'A';
        }

        /* if this next if() triggers, we're fucked. */
        if(current_uid[3] == 'Z')
        {
                current_uid[i] = 'A';
                s_assert(0);
        }
        else
                current_uid[i]++;

        return current_uid;
}

/*
 * close_connection
 *        Close the physical connection. This function must make
 *        MyConnect(client_p) == FALSE, and set client_p->from == NULL.
 */
void
close_connection(struct Client *client_p)
{
        s_assert(client_p != NULL);
        if(client_p == NULL)
                return;

        s_assert(MyConnect(client_p));
        if(!MyConnect(client_p))
                return;
        
        if(IsServer(client_p))
        {
                struct server_conf *server_p;

                ServerStats->is_sv++;
                ServerStats->is_sbs += client_p->localClient->sendB;
                ServerStats->is_sbr += client_p->localClient->receiveB;
                ServerStats->is_sks += client_p->localClient->sendK;
                ServerStats->is_skr += client_p->localClient->receiveK;
                ServerStats->is_sti += CurrentTime - client_p->localClient->firsttime;
                if(ServerStats->is_sbs > 2047)
                {
                        ServerStats->is_sks += (ServerStats->is_sbs >> 10);
                        ServerStats->is_sbs &= 0x3ff;
                }
                if(ServerStats->is_sbr > 2047)
                {
                        ServerStats->is_skr += (ServerStats->is_sbr >> 10);
                        ServerStats->is_sbr &= 0x3ff;
                }

                /*
                 * If the connection has been up for a long amount of time, schedule
                 * a 'quick' reconnect, else reset the next-connect cycle.
                 */
                if((server_p = find_server_conf(client_p->name)) != NULL)
                {
                        /*
                         * Reschedule a faster reconnect, if this was a automatically
                         * connected configuration entry. (Note that if we have had
                         * a rehash in between, the status has been changed to
                         * CONF_ILLEGAL). But only do this if it was a "good" link.
                         */
                        server_p->hold = time(NULL);
                        server_p->hold +=
                                (server_p->hold - client_p->localClient->lasttime >
                                 HANGONGOODLINK) ? HANGONRETRYDELAY : ConFreq(server_p->class);
                }

        }
        else if(IsClient(client_p))
        {
                ServerStats->is_cl++;
                ServerStats->is_cbs += client_p->localClient->sendB;
                ServerStats->is_cbr += client_p->localClient->receiveB;
                ServerStats->is_cks += client_p->localClient->sendK;
                ServerStats->is_ckr += client_p->localClient->receiveK;
                ServerStats->is_cti += CurrentTime - client_p->localClient->firsttime;
                if(ServerStats->is_cbs > 2047)
                {
                        ServerStats->is_cks += (ServerStats->is_cbs >> 10);
                        ServerStats->is_cbs &= 0x3ff;
                }
                if(ServerStats->is_cbr > 2047)
                {
                        ServerStats->is_ckr += (ServerStats->is_cbr >> 10);
                        ServerStats->is_cbr &= 0x3ff;
                }
        }
        else
                ServerStats->is_ni++;

        if(-1 < client_p->localClient->fd)
        {
                /* attempt to flush any pending dbufs. Evil, but .. -- adrian */
                if(!IsIOError(client_p))
                        send_queued_write(client_p->localClient->fd, client_p);

                comm_close(client_p->localClient->fd);
                client_p->localClient->fd = -1;
        }

        if(-1 < client_p->localClient->ctrlfd)
        {
                comm_close(client_p->localClient->ctrlfd);
                client_p->localClient->ctrlfd = -1;
        }

        linebuf_donebuf(&client_p->localClient->buf_sendq);
        linebuf_donebuf(&client_p->localClient->buf_recvq);
        detach_conf(client_p);

        /* XXX shouldnt really be done here. */
        detach_server_conf(client_p);

        client_p->from = NULL;  /* ...this should catch them! >:) --msa */
        ClearMyConnect(client_p);
        SetIOError(client_p);
}



void
error_exit_client(struct Client *client_p, int error)
{
        /*
         * ...hmm, with non-blocking sockets we might get
         * here from quite valid reasons, although.. why
         * would select report "data available" when there
         * wasn't... so, this must be an error anyway...  --msa
         * actually, EOF occurs when read() returns 0 and
         * in due course, select() returns that fd as ready
         * for reading even though it ends up being an EOF. -avalon
         */
        char errmsg[255];
        int current_error = comm_get_sockerr(client_p->localClient->fd);

        SetIOError(client_p);

        if(IsServer(client_p) || IsHandshake(client_p))
        {
                if(error == 0)
                {
                        sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) && !IsServer(client_p) ? L_NETWIDE : L_ALL,
                                             "Server %s closed the connection",
                                             get_server_name(client_p, SHOW_IP));

                        ilog(L_SERVER, "Server %s closed the connection",
                             log_client_name(client_p, SHOW_IP));
                }
                else
                {
                        sendto_realops_snomask(SNO_GENERAL, is_remote_connect(client_p) && !IsServer(client_p) ? L_NETWIDE : L_ALL,
                                        "Lost connection to %s: %s",
                                        client_p->name, strerror(current_error));
                        ilog(L_SERVER, "Lost connection to %s: %s",
                                log_client_name(client_p, SHOW_IP), strerror(current_error));
                }
        }

        if(error == 0)
                strlcpy(errmsg, "Remote host closed the connection", sizeof(errmsg));
        else
                ircsnprintf(errmsg, sizeof(errmsg), "Read error: %s", strerror(current_error));

        exit_client(client_p, client_p, &me, errmsg);
}