2004-05-09 Michael Poole <mdpoole@troilus.org>

[ircu2.10.12-pk.git] / ircd / channel.c

/*
 * IRC - Internet Relay Chat, ircd/channel.c
 * Copyright (C) 1990 Jarkko Oikarinen and
 *                    University of Oulu, Co Center
 *
 * 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 1, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 */
#include "config.h"

#include "channel.h"
#include "client.h"
#include "destruct_event.h"
#include "hash.h"
#include "ircd.h"
#include "ircd_alloc.h"
#include "ircd_chattr.h"
#include "ircd_defs.h"
#include "ircd_features.h"
#include "ircd_log.h"
#include "ircd_reply.h"
#include "ircd_snprintf.h"
#include "ircd_string.h"
#include "list.h"
#include "match.h"
#include "msg.h"
#include "msgq.h"
#include "numeric.h"
#include "numnicks.h"
#include "querycmds.h"
#include "s_bsd.h"
#include "s_conf.h"
#include "s_debug.h"
#include "s_misc.h"
#include "s_user.h"
#include "send.h"
#include "struct.h"
#include "support.h"
#include "sys.h"
#include "whowas.h"

#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct Channel* GlobalChannelList = 0;

static unsigned int membershipAllocCount;
static struct Membership* membershipFreeList;

void del_invite(struct Client *, struct Channel *);

const char* const PartFmt1     = ":%s " MSG_PART " %s";
const char* const PartFmt2     = ":%s " MSG_PART " %s :%s";
const char* const PartFmt1serv = "%s%s " TOK_PART " %s";
const char* const PartFmt2serv = "%s%s " TOK_PART " %s :%s";


static struct SLink* next_ban;
static struct SLink* prev_ban;
static struct SLink* removed_bans_list;

/*
 * Use a global variable to remember if an oper set a mode on a local channel. Ugly,
 * but the only way to do it without changing set_mode intensively.
 */
int LocalChanOperMode = 0;

#if !defined(NDEBUG)
/*
 * return the length (>=0) of a chain of links.
 */
static int list_length(struct SLink *lp)
{
  int count = 0;

  for (; lp; lp = lp->next)
    ++count;
  return count;
}
#endif

struct Membership* find_member_link(struct Channel* chptr, const struct Client* cptr)
{
  struct Membership *m;
  assert(0 != cptr);
  assert(0 != chptr);
  
  /* Servers don't have member links */
  if (IsServer(cptr)||IsMe(cptr))
     return 0;
  
  /* +k users are typically on a LOT of channels.  So we iterate over who
   * is in the channel.  X/W are +k and are in about 5800 channels each.
   * however there are typically no more than 1000 people in a channel
   * at a time.
   */
  if (IsChannelService(cptr)) {
    m = chptr->members;
    while (m) {
      assert(m->channel == chptr);
      if (m->user == cptr)
        return m;
      m = m->next_member;
    }
  }
  /* Users on the other hand aren't allowed on more than 15 channels.  50%
   * of users that are on channels are on 2 or less, 95% are on 7 or less,
   * and 99% are on 10 or less.
   */
  else {
   m = (cli_user(cptr))->channel;
   while (m) {
     assert(m->user == cptr);
     if (m->channel == chptr)
       return m;
     m = m->next_channel;
   }
  }
  return 0;
}

/*
 * 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* sptr, const char* user, int* chasing)
{
  struct Client* who = FindClient(user);

  if (chasing)
    *chasing = 0;
  if (who)
    return who;

  if (!(who = get_history(user, feature_int(FEAT_KILLCHASETIMELIMIT)))) {
    send_reply(sptr, ERR_NOSUCHNICK, user);
    return 0;
  }
  if (chasing)
    *chasing = 1;
  return who;
}

/*
 * Create a string of form "foo!bar@fubar" given foo, bar and fubar
 * as the parameters.  If NULL, they become "*".
 */
#define NUH_BUFSIZE     (NICKLEN + USERLEN + HOSTLEN + 3)
static char *make_nick_user_host(char *namebuf, const char *nick,
                                 const char *name, const char *host)
{
  ircd_snprintf(0, namebuf, NUH_BUFSIZE, "%s!%s@%s", nick, name, host);
  return namebuf;
}

/*
 * Create a string of form "foo!bar@123.456.789.123" given foo, bar and the
 * IP-number as the parameters.  If NULL, they become "*".
 */
#define NUI_BUFSIZE     (NICKLEN + USERLEN + 16 + 3)
static char *make_nick_user_ip(char *ipbuf, char *nick, char *name,
                               struct in_addr ip)
{
  ircd_snprintf(0, ipbuf, NUI_BUFSIZE, "%s!%s@%s", nick, name,
                ircd_ntoa((const char*) &ip));
  return ipbuf;
}

/*
 * Subtract one user from channel i (and free channel
 * block, if channel became empty).
 * Returns: true  (1) if channel still has members.
 *          false (0) if the channel is now empty.
 */
int sub1_from_channel(struct Channel* chptr)
{
  if (chptr->users > 1)         /* Can be 0, called for an empty channel too */
  {
    assert(0 != chptr->members);
    --chptr->users;
    return 1;
  }

  chptr->users = 0;

  /*
   * Also channels without Apass set need to be kept alive,
   * otherwise Bad Guys(tm) would be able to takeover
   * existing channels too easily, and then set an Apass!
   * However, if a channel without Apass becomes empty
   * then we try to be kind to them and remove possible
   * limiting modes.
   */
  chptr->mode.mode &= ~MODE_INVITEONLY;
  chptr->mode.limit = 0;
  /*
   * We do NOT reset a possible key or bans because when
   * the 'channel owners' can't get in because of a key
   * or ban then apparently there was a fight/takeover
   * on the channel and we want them to contact IRC opers
   * who then will educate them on the use of Apass/upass.
   */

   if (feature_bool(FEAT_OPLEVELS)) {
  if (TStime() - chptr->creationtime < 172800)  /* Channel younger than 48 hours? */
    schedule_destruct_event_1m(chptr);          /* Get rid of it in approximately 4-5 minutes */
  else
    schedule_destruct_event_48h(chptr);         /* Get rid of it in approximately 48 hours */
   } else
       destruct_channel(chptr);

  return 0;
}

int destruct_channel(struct Channel* chptr)
{
  struct SLink *tmp;
  struct SLink *obtmp;

  assert(0 == chptr->members);

  /* Channel became (or was) empty: Remove channel */
  if (is_listed(chptr))
  {
    int i;
    for (i = 0; i <= HighestFd; i++)
    {
      struct Client *acptr = 0;
      if ((acptr = LocalClientArray[i]) && cli_listing(acptr) &&
          (cli_listing(acptr))->chptr == chptr)
      {
        list_next_channels(acptr, 1);
        break;                  /* Only one client can list a channel */
      }
    }
  }
  /*
   * Now, find all invite links from channel structure
   */
  while ((tmp = chptr->invites))
    del_invite(tmp->value.cptr, chptr);

  tmp = chptr->banlist;
  while (tmp)
  {
    obtmp = tmp;
    tmp = tmp->next;
    MyFree(obtmp->value.ban.banstr);
    MyFree(obtmp->value.ban.who);
    free_link(obtmp);
  }
  if (chptr->prev)
    chptr->prev->next = chptr->next;
  else
    GlobalChannelList = chptr->next;
  if (chptr->next)
    chptr->next->prev = chptr->prev;
  hRemChannel(chptr);
  --UserStats.channels;
  /*
   * make sure that channel actually got removed from hash table
   */
  assert(chptr->hnext == chptr);
  MyFree(chptr);
  return 0;
}

/*
 * add_banid
 *
 * `cptr' must be the client adding the ban.
 *
 * If `change' is true then add `banid' to channel `chptr'.
 * Returns 0 if the ban was added.
 * Returns -2 if the ban already existed and was marked CHFL_BURST_BAN_WIPEOUT.
 * Return -1 otherwise.
 *
 * Those bans that overlapped with `banid' are flagged with CHFL_BAN_OVERLAPPED
 * when `change' is false, otherwise they will be removed from the banlist.
 * Subsequently calls to next_overlapped_ban() or next_removed_overlapped_ban()
 * respectively will return these bans until NULL is returned.
 *
 * If `firsttime' is true, the ban list as returned by next_overlapped_ban()
 * is reset (unless a non-zero value is returned, in which case the
 * CHFL_BAN_OVERLAPPED flag might not have been reset!).
 *
 * --Run
 */
int add_banid(struct Client *cptr, struct Channel *chptr, char *banid,
                     int change, int firsttime)
{
  struct SLink*  ban;
  struct SLink** banp;
  int            cnt = 0;
  int            removed_bans = 0;
  int            len = strlen(banid);

  if (firsttime)
  {
    next_ban = NULL;
    assert(0 == prev_ban);
    assert(0 == removed_bans_list);
  }
  if (MyUser(cptr))
    collapse(banid);
  for (banp = &chptr->banlist; *banp;)
  {
    len += strlen((*banp)->value.ban.banstr);
    ++cnt;
    if (((*banp)->flags & CHFL_BURST_BAN_WIPEOUT))
    {
      if (!strcmp((*banp)->value.ban.banstr, banid))
      {
        (*banp)->flags &= ~CHFL_BURST_BAN_WIPEOUT;
        return -2;
      }
    }
    else if (!mmatch((*banp)->value.ban.banstr, banid))
      return -1;
    if (!mmatch(banid, (*banp)->value.ban.banstr))
    {
      struct SLink *tmp = *banp;
      if (change)
      {
        if (MyUser(cptr))
        {
          cnt--;
          len -= strlen(tmp->value.ban.banstr);
        }
        *banp = tmp->next;
        /* These will be sent to the user later as -b */
        tmp->next = removed_bans_list;
        removed_bans_list = tmp;
        removed_bans = 1;
      }
      else if (!(tmp->flags & CHFL_BURST_BAN_WIPEOUT))
      {
        tmp->flags |= CHFL_BAN_OVERLAPPED;
        if (!next_ban)
          next_ban = tmp;
        banp = &tmp->next;
      }
      else
        banp = &tmp->next;
    }
    else
    {
      if (firsttime)
        (*banp)->flags &= ~CHFL_BAN_OVERLAPPED;
      banp = &(*banp)->next;
    }
  }
  if (MyUser(cptr) && !removed_bans &&
      (len > (feature_int(FEAT_AVBANLEN) * feature_int(FEAT_MAXBANS)) ||
       (cnt >= feature_int(FEAT_MAXBANS))))
  {
    send_reply(cptr, ERR_BANLISTFULL, chptr->chname, banid);
    return -1;
  }
  if (change)
  {
    char*              ip_start;
    struct Membership* member;
    ban = make_link();
    ban->next = chptr->banlist;

    ban->value.ban.banstr = (char*) MyMalloc(strlen(banid) + 1);
    assert(0 != ban->value.ban.banstr);
    strcpy(ban->value.ban.banstr, banid);

    if (IsServer(cptr) && feature_bool(FEAT_HIS_BANWHO))
      DupString(ban->value.ban.who, cli_name(&me));
    else
      DupString(ban->value.ban.who, cli_name(cptr));
    assert(0 != ban->value.ban.who);

    ban->value.ban.when = TStime();
    ban->flags = CHFL_BAN;      /* This bit is never used I think... */
    if ((ip_start = strrchr(banid, '@')) && check_if_ipmask(ip_start + 1))
      ban->flags |= CHFL_BAN_IPMASK;
    chptr->banlist = ban;

    /*
     * Erase ban-valid-bit
     */
    for (member = chptr->members; member; member = member->next_member)
      ClearBanValid(member);     /* `ban' == channel member ! */
  }
  return 0;
}

struct SLink *next_removed_overlapped_ban(void)
{
  struct SLink *tmp = removed_bans_list;
  if (prev_ban)
  {
    if (prev_ban->value.ban.banstr)     /* Can be set to NULL in set_mode() */
      MyFree(prev_ban->value.ban.banstr);
    MyFree(prev_ban->value.ban.who);
    free_link(prev_ban);
    prev_ban = 0;
  }
  if (tmp)
    removed_bans_list = removed_bans_list->next;
  prev_ban = tmp;
  return tmp;
}

/*
 * find_channel_member - returns Membership * if a person is joined and not a zombie
 */
struct Membership* find_channel_member(struct Client* cptr, struct Channel* chptr)
{
  struct Membership* member;
  assert(0 != chptr);

  member = find_member_link(chptr, cptr);
  return (member && !IsZombie(member)) ? member : 0;
}

/*
 * is_banned - a non-zero value if banned else 0.
 */
static int is_banned(struct Client *cptr, struct Channel *chptr,
                     struct Membership* member)
{
  struct SLink* tmp;
  char          tmphost[HOSTLEN + 1];
  char          nu_host[NUH_BUFSIZE];
  char          nu_realhost[NUH_BUFSIZE];
  char          nu_ip[NUI_BUFSIZE];
  char*         s;
  char*         sr = NULL;
  char*         ip_s = NULL;

  if (!IsUser(cptr))
    return 0;

  if (member && IsBanValid(member))
    return IsBanned(member);

  s = make_nick_user_host(nu_host, cli_name(cptr), (cli_user(cptr))->username,
                          (cli_user(cptr))->host);
  if (IsAccount(cptr))
  {
    if (HasHiddenHost(cptr))
    {
      sr = make_nick_user_host(nu_realhost, cli_name(cptr),
                               (cli_user(cptr))->username,
                               cli_user(cptr)->realhost);
    }
    else
    {
      ircd_snprintf(0, tmphost, HOSTLEN, "%s.%s",
                    cli_user(cptr)->account, feature_str(FEAT_HIDDEN_HOST));
      sr = make_nick_user_host(nu_realhost, cli_name(cptr),
                               cli_user(cptr)->username,
                               tmphost);      
    }
  }

  for (tmp = chptr->banlist; tmp; tmp = tmp->next) {
    if ((tmp->flags & CHFL_BAN_IPMASK)) {
      if (!ip_s)
        ip_s = make_nick_user_ip(nu_ip, cli_name(cptr),
                                 (cli_user(cptr))->username, cli_ip(cptr));
      if (match(tmp->value.ban.banstr, ip_s) == 0)
        break;
    }
    else if (match(tmp->value.ban.banstr, s) == 0)
      break;
    else if (sr && match(tmp->value.ban.banstr, sr) == 0)
      break;
  }

  if (member) {
    SetBanValid(member);
    if (tmp) {
      SetBanned(member);
      return 1;
    }
    else {
      ClearBanned(member);
      return 0;
    }
  }

  return (tmp != NULL);
}

/*
 * adds a user to a channel by adding another link to the channels member
 * chain.
 */
void add_user_to_channel(struct Channel* chptr, struct Client* who,
                                unsigned int flags, int oplevel)
{
  assert(0 != chptr);
  assert(0 != who);

  if (cli_user(who)) {
   
    struct Membership* member = membershipFreeList;
    if (member)
      membershipFreeList = member->next_member;
    else {
      member = (struct Membership*) MyMalloc(sizeof(struct Membership));
      ++membershipAllocCount;
    }

    assert(0 != member);
    member->user         = who;
    member->channel      = chptr;
    member->status       = flags;
    member->oplevel      = oplevel;

    member->next_member  = chptr->members;
    if (member->next_member)
      member->next_member->prev_member = member;
    member->prev_member  = 0; 
    chptr->members       = member;

    member->next_channel = (cli_user(who))->channel;
    if (member->next_channel)
      member->next_channel->prev_channel = member;
    member->prev_channel = 0;
    (cli_user(who))->channel = member;

    if (chptr->destruct_event)
      remove_destruct_event(chptr);
    ++chptr->users;
    ++((cli_user(who))->joined);
  }
}

static int remove_member_from_channel(struct Membership* member)
{
  struct Channel* chptr;
  assert(0 != member);
  chptr = member->channel;
  /*
   * unlink channel member list
   */
  if (member->next_member)
    member->next_member->prev_member = member->prev_member;
  if (member->prev_member)
    member->prev_member->next_member = member->next_member;
  else
    member->channel->members = member->next_member; 
      
  /*
   * unlink client channel list
   */
  if (member->next_channel)
    member->next_channel->prev_channel = member->prev_channel;
  if (member->prev_channel)
    member->prev_channel->next_channel = member->next_channel;
  else
    (cli_user(member->user))->channel = member->next_channel;

  --(cli_user(member->user))->joined;

  member->next_member = membershipFreeList;
  membershipFreeList = member;

  return sub1_from_channel(chptr);
}

static int channel_all_zombies(struct Channel* chptr)
{
  struct Membership* member;

  for (member = chptr->members; member; member = member->next_member) {
    if (!IsZombie(member))
      return 0;
  }
  return 1;
}
      

void remove_user_from_channel(struct Client* cptr, struct Channel* chptr)
{
  
  struct Membership* member;
  assert(0 != chptr);

  if ((member = find_member_link(chptr, cptr))) {
    if (remove_member_from_channel(member)) {
      if (channel_all_zombies(chptr)) {
        /*
         * XXX - this looks dangerous but isn't if we got the referential
         * integrity right for channels
         */
        while (remove_member_from_channel(chptr->members))
          ;
      }
    }
  }
}

void remove_user_from_all_channels(struct Client* cptr)
{
  struct Membership* chan;
  assert(0 != cptr);
  assert(0 != cli_user(cptr));

  while ((chan = (cli_user(cptr))->channel))
    remove_user_from_channel(cptr, chan->channel);
}

int is_chan_op(struct Client *cptr, struct Channel *chptr)
{
  struct Membership* member;
  assert(chptr);
  if ((member = find_member_link(chptr, cptr)))
    return (!IsZombie(member) && IsChanOp(member));

  return 0;
}

int is_zombie(struct Client *cptr, struct Channel *chptr)
{
  struct Membership* member;

  assert(0 != chptr);

  if ((member = find_member_link(chptr, cptr)))
      return IsZombie(member);
  return 0;
}

int has_voice(struct Client* cptr, struct Channel* chptr)
{
  struct Membership* member;

  assert(0 != chptr);
  if ((member = find_member_link(chptr, cptr)))
    return (!IsZombie(member) && HasVoice(member));

  return 0;
}

int member_can_send_to_channel(struct Membership* member)
{
  assert(0 != member);

  /* Discourage using the Apass to get op.  They should use the upass. */
  if (IsChannelManager(member) && *member->channel->mode.upass)
    return 0;

  if (IsVoicedOrOpped(member))
    return 1;
  /*
   * If it's moderated, and you aren't a priviledged user, you can't
   * speak.  
   */
  if (member->channel->mode.mode & MODE_MODERATED)
    return 0;
  /*
   * If you're banned then you can't speak either.
   * but because of the amount of CPU time that is_banned chews
   * we only check it for our clients.
   */
  if (MyUser(member->user) && is_banned(member->user, member->channel, member))
    return 0;
  return 1;
}

int client_can_send_to_channel(struct Client *cptr, struct Channel *chptr)
{
  struct Membership *member;
  assert(0 != cptr); 
  /*
   * Servers can always speak on channels.
   */
  if (IsServer(cptr))
    return 1;

  member = find_channel_member(cptr, chptr);

  /*
   * You can't speak if you're off channel, and it is +n (no external messages)
   * or +m (moderated).
   */
  if (!member) {
    if ((chptr->mode.mode & (MODE_NOPRIVMSGS|MODE_MODERATED)) ||
        ((chptr->mode.mode & MODE_REGONLY) && !IsAccount(cptr)))
      return 0;
    else
      return !is_banned(cptr, chptr, NULL);
  }
  return member_can_send_to_channel(member); 
}

/*
 * find_no_nickchange_channel
 * if a member and not (opped or voiced) and (banned or moderated)
 * return the name of the first channel banned on
 */
const char* find_no_nickchange_channel(struct Client* cptr)
{
  if (MyUser(cptr)) {
    struct Membership* member;
    for (member = (cli_user(cptr))->channel; member;
         member = member->next_channel) {
        if (!IsVoicedOrOpped(member) &&
            (is_banned(cptr, member->channel, member) ||
             (member->channel->mode.mode & MODE_MODERATED)))
        return member->channel->chname;
    }
  }
  return 0;
}


/*
 * write the "simple" list of channel modes for channel chptr onto buffer mbuf
 * with the parameters in pbuf.
 */
void channel_modes(struct Client *cptr, char *mbuf, char *pbuf, int buflen,
                          struct Channel *chptr, struct Membership *member)
{
  int previous_parameter = 0;

  assert(0 != mbuf);
  assert(0 != pbuf);
  assert(0 != chptr);

  *mbuf++ = '+';
  if (chptr->mode.mode & MODE_SECRET)
    *mbuf++ = 's';
  else if (chptr->mode.mode & MODE_PRIVATE)
    *mbuf++ = 'p';
  if (chptr->mode.mode & MODE_MODERATED)
    *mbuf++ = 'm';
  if (chptr->mode.mode & MODE_TOPICLIMIT)
    *mbuf++ = 't';
  if (chptr->mode.mode & MODE_INVITEONLY)
    *mbuf++ = 'i';
  if (chptr->mode.mode & MODE_NOPRIVMSGS)
    *mbuf++ = 'n';
  if (chptr->mode.mode & MODE_REGONLY)
    *mbuf++ = 'r';
  if (chptr->mode.limit) {
    *mbuf++ = 'l';
    ircd_snprintf(0, pbuf, buflen, "%u", chptr->mode.limit);
    previous_parameter = 1;
  }

  if (*chptr->mode.key) {
    *mbuf++ = 'k';
    if (previous_parameter)
      strcat(pbuf, " ");
    if (is_chan_op(cptr, chptr) || IsServer(cptr)) {
      strcat(pbuf, chptr->mode.key);
    } else
      strcat(pbuf, "*");
    previous_parameter = 1;
  }
  if (*chptr->mode.apass) {
    *mbuf++ = 'A';
    if (previous_parameter)
      strcat(pbuf, " ");
    if (IsServer(cptr)) {
      strcat(pbuf, chptr->mode.apass);
    } else
      strcat(pbuf, "*");
    previous_parameter = 1;
  }
  if (*chptr->mode.upass) {
    *mbuf++ = 'u';
    if (previous_parameter)
      strcat(pbuf, " ");
    if (IsServer(cptr) || (member && IsChanOp(member) && OpLevel(member) == 0)) {
      strcat(pbuf, chptr->mode.upass);
    } else
      strcat(pbuf, "*");
  }
  *mbuf = '\0';
}

int compare_member_oplevel(const void *mp1, const void *mp2)
{
  struct Membership const* member1 = *(struct Membership const**)mp1;
  struct Membership const* member2 = *(struct Membership const**)mp2;
  if (member1->oplevel == member2->oplevel)
    return 0;
  return (member1->oplevel < member2->oplevel) ? -1 : 1;
}

/*
 * send "cptr" a full list of the modes for channel chptr.
 */
void send_channel_modes(struct Client *cptr, struct Channel *chptr)
{
  /* The order in which modes are generated is now mandatory */
  static unsigned int current_flags[4] =
      { 0, CHFL_VOICE, CHFL_CHANOP, CHFL_CHANOP | CHFL_VOICE };
  int                first = 1;
  int                full  = 1;
  int                flag_cnt = 0;
  int                new_mode = 0;
  size_t             len;
  struct Membership* member;
  struct SLink*      lp2;
  char modebuf[MODEBUFLEN];
  char parabuf[MODEBUFLEN];
  struct MsgBuf *mb;
  int                 number_of_ops = 0;
  int                 opped_members_index = 0;
  struct Membership** opped_members = NULL;
  int                 last_oplevel = 0;

  assert(0 != cptr);
  assert(0 != chptr); 

  if (IsLocalChannel(chptr->chname))
    return;

  member = chptr->members;
  lp2 = chptr->banlist;

  *modebuf = *parabuf = '\0';
  channel_modes(cptr, modebuf, parabuf, sizeof(parabuf), chptr, 0);

  for (first = 1; full; first = 0)      /* Loop for multiple messages */
  {
    full = 0;                   /* Assume by default we get it
                                 all in one message */

    /* (Continued) prefix: "<Y> B <channel> <TS>" */
    /* is there any better way we can do this? */
    mb = msgq_make(&me, "%C " TOK_BURST " %H %Tu", &me, chptr,
                   chptr->creationtime);

    if (first && modebuf[1])    /* Add simple modes (Aiklmnpstu)
                                 if first message */
    {
      /* prefix: "<Y> B <channel> <TS>[ <modes>[ <params>]]" */
      msgq_append(&me, mb, " %s", modebuf);

      if (*parabuf)
        msgq_append(&me, mb, " %s", parabuf);
    }

    /*
     * Attach nicks, comma seperated " nick[:modes],nick[:modes],..."
     *
     * First find all opless members.
     * Run 2 times over all members, to group the members with
     * and without voice together.
     * Then run 2 times over all opped members (which are ordered
     * by op-level) to also group voice and non-voice together.
     */
    for (first = 1; flag_cnt < 4; new_mode = 1, ++flag_cnt)
    {
      while (member)
      {
        if (flag_cnt < 2 && IsChanOp(member))
        {
          /*
           * The first loop (to find all non-voice/op), we count the ops.
           * The second loop (to find all voiced non-ops), store the ops
           * in a dynamic array.
           */
          if (flag_cnt == 0)
            ++number_of_ops;
          else
            opped_members[opped_members_index++] = member;
        }
        /* Only handle the members with the flags that we are interested in. */
        if ((member->status & CHFL_VOICED_OR_OPPED) == current_flags[flag_cnt])
        {
          if (msgq_bufleft(mb) < NUMNICKLEN + 3 + MAXOPLEVELDIGITS)
            /* The 3 + MAXOPLEVELDIGITS is a possible ",:v999". */
          {
            full = 1;           /* Make sure we continue after
                                   sending it so far */
            /* Ensure the new BURST line contains the current
             * ":mode", except when there is no mode yet. */
            new_mode = (flag_cnt > 0) ? 1 : 0;
            break;              /* Do not add this member to this message */
          }
          msgq_append(&me, mb, "%c%C", first ? ' ' : ',', member->user);
          first = 0;              /* From now on, use commas to add new nicks */

          /*
           * Do we have a nick with a new mode ?
           * Or are we starting a new BURST line?
           */
          if (new_mode)
          {
            /*
             * This means we are at the _first_ member that has only
             * voice, or the first member that has only ops, or the
             * first member that has voice and ops (so we get here
             * at most three times, plus once for every start of
             * a continued BURST line where only these modes is current.
             * In the two cases where the current mode includes ops,
             * we need to add the _absolute_ value of the oplevel to the mode.
             */
            char tbuf[3 + MAXOPLEVELDIGITS] = ":";
            int loc = 1;

            if (HasVoice(member))       /* flag_cnt == 1 or 3 */
              tbuf[loc++] = 'v';
            if (IsChanOp(member))       /* flag_cnt == 2 or 3 */
            {
              /* append the absolute value of the oplevel */
              loc += ircd_snprintf(0, tbuf + loc, sizeof(tbuf) - loc, "%u", member->oplevel);
              last_oplevel = member->oplevel;
            }
            tbuf[loc] = '\0';
            msgq_append(&me, mb, tbuf);
            new_mode = 0;
          }
          else if (flag_cnt > 1 && last_oplevel != member->oplevel)
          {
            /*
             * This can't be the first member of a (continued) BURST
             * message because then either flag_cnt == 0 or new_mode == 1
             * Now we need to append the incremental value of the oplevel.
             */
            char tbuf[2 + MAXOPLEVELDIGITS];
            ircd_snprintf(0, tbuf, sizeof(tbuf), ":%u", member->oplevel - last_oplevel);
            last_oplevel = member->oplevel;
            msgq_append(&me, mb, tbuf);
          }
        }
        /* Go to the next `member'. */
        if (flag_cnt < 2)
          member = member->next_member;
        else
          member = opped_members[++opped_members_index];
      }
      if (full)
        break;

      /* Point `member' at the start of the list again. */
      if (flag_cnt == 0)
      {
        member = chptr->members;
        /* Now, after one loop, we know the number of ops and can
         * allocate the dynamic array with pointer to the ops. */
        opped_members = (struct Membership**)
          MyMalloc((number_of_ops + 1) * sizeof(struct Membership*));
        opped_members[number_of_ops] = NULL;    /* Needed for loop termination */
      }
      else
      {
        /* At the end of the second loop, sort the opped members with
         * increasing op-level, so that we will output them in the
         * correct order (and all op-level increments stay positive) */
        if (flag_cnt == 1)
          qsort(opped_members, number_of_ops,
                sizeof(struct Membership*), compare_member_oplevel);
        /* The third and fourth loop run only over the opped members. */
        member = opped_members[(opped_members_index = 0)];
      }

    } /* loop over 0,+v,+o,+ov */

    if (!full)
    {
      /* Attach all bans, space seperated " :%ban ban ..." */
      for (first = 2; lp2; lp2 = lp2->next)
      {
        len = strlen(lp2->value.ban.banstr);
        if (msgq_bufleft(mb) < len + 1 + first)
          /* The +1 stands for the added ' '.
           * The +first stands for the added ":%".
           */
        {
          full = 1;
          break;
        }
        msgq_append(&me, mb, " %s%s", first ? ":%" : "",
                    lp2->value.ban.banstr);
        first = 0;
      }
    }

    send_buffer(cptr, mb, 0);  /* Send this message */
    msgq_clean(mb);
  }                             /* Continue when there was something
                                 that didn't fit (full==1) */
  if (opped_members)
    MyFree(opped_members);
}

/*
 * pretty_mask
 *
 * by Carlo Wood (Run), 05 Oct 1998.
 *
 * Canonify a mask.
 *
 * When the nick is longer then NICKLEN, it is cut off (its an error of course).
 * When the user name or host name are too long (USERLEN and HOSTLEN
 * respectively) then they are cut off at the start with a '*'.
 *
 * The following transformations are made:
 *
 * 1)   xxx             -> nick!*@*
 * 2)   xxx.xxx         -> *!*@host
 * 3)   xxx!yyy         -> nick!user@*
 * 4)   xxx@yyy         -> *!user@host
 * 5)   xxx!yyy@zzz     -> nick!user@host
 */
char *pretty_mask(char *mask)
{
  static char star[2] = { '*', 0 };
  static char retmask[NUH_BUFSIZE];
  char *last_dot = NULL;
  char *ptr;

  /* Case 1: default */
  char *nick = mask;
  char *user = star;
  char *host = star;

  /* Do a _single_ pass through the characters of the mask: */
  for (ptr = mask; *ptr; ++ptr)
  {
    if (*ptr == '!')
    {
      /* Case 3 or 5: Found first '!' (without finding a '@' yet) */
      user = ++ptr;
      host = star;
    }
    else if (*ptr == '@')
    {
      /* Case 4: Found last '@' (without finding a '!' yet) */
      nick = star;
      user = mask;
      host = ++ptr;
    }
    else if (*ptr == '.')
    {
      /* Case 2: Found last '.' (without finding a '!' or '@' yet) */
      last_dot = ptr;
      continue;
    }
    else
      continue;
    for (; *ptr; ++ptr)
    {
      if (*ptr == '@')
      {
        /* Case 4 or 5: Found last '@' */
        host = ptr + 1;
      }
    }
    break;
  }
  if (user == star && last_dot)
  {
    /* Case 2: */
    nick = star;
    user = star;
    host = mask;
  }
  /* Check lengths */
  if (nick != star)
  {
    char *nick_end = (user != star) ? user - 1 : ptr;
    if (nick_end - nick > NICKLEN)
      nick[NICKLEN] = 0;
    *nick_end = 0;
  }
  if (user != star)
  {
    char *user_end = (host != star) ? host - 1 : ptr;
    if (user_end - user > USERLEN)
    {
      user = user_end - USERLEN;
      *user = '*';
    }
    *user_end = 0;
  }
  if (host != star && ptr - host > HOSTLEN)
  {
    host = ptr - HOSTLEN;
    *host = '*';
  }
  return make_nick_user_host(retmask, nick, user, host);
}

static void send_ban_list(struct Client* cptr, struct Channel* chptr)
{
  struct SLink* lp;

  assert(0 != cptr);
  assert(0 != chptr);

  for (lp = chptr->banlist; lp; lp = lp->next)
    send_reply(cptr, RPL_BANLIST, chptr->chname, lp->value.ban.banstr,
               lp->value.ban.who, lp->value.ban.when);

  send_reply(cptr, RPL_ENDOFBANLIST, chptr->chname);
}

/* We are now treating the <key> part of /join <channel list> <key> as a key
 * ring; that is, we try one key against the actual channel key, and if that
 * doesn't work, we try the next one, and so on. -Kev -Texaco
 * Returns: 0 on match, 1 otherwise
 * This version contributed by SeKs <intru@info.polymtl.ca>
 */
static int compall(char *key, char *keyring)
{
  char *p1;

top:
  p1 = key;                     /* point to the key... */
  while (*p1 && *p1 == *keyring)
  {                             /* step through the key and ring until they
                                   don't match... */
    p1++;
    keyring++;
  }

  if (!*p1 && (!*keyring || *keyring == ','))
    /* ok, if we're at the end of the and also at the end of one of the keys
       in the keyring, we have a match */
    return 0;

  if (!*keyring)                /* if we're at the end of the key ring, there
                                   weren't any matches, so we return 1 */
    return 1;

  /* Not at the end of the key ring, so step
     through to the next key in the ring: */
  while (*keyring && *(keyring++) != ',');

  goto top;                     /* and check it against the key */
}

int can_join(struct Client *sptr, struct Channel *chptr, char *key)
{
  struct SLink *lp;
  int overrideJoin = 0;  
  
  /*
   * Now a banned user CAN join if invited -- Nemesi
   * Now a user CAN escape channel limit if invited -- bfriendly
   * Now a user CAN escape anything if invited -- Isomer
   */

  for (lp = (cli_user(sptr))->invited; lp; lp = lp->next)
    if (lp->value.chptr == chptr)
      return 0;
  
  /* An oper can force a join on a local channel using "OVERRIDE" as the key. 
     a HACK(4) notice will be sent if he would not have been supposed
     to join normally. */ 
  if (IsLocalChannel(chptr->chname) && HasPriv(sptr, PRIV_WALK_LCHAN) &&
      !BadPtr(key) && compall("OVERRIDE",chptr->mode.key) != 0 &&
      compall("OVERRIDE",key) == 0)
    overrideJoin = MAGIC_OPER_OVERRIDE;

  if (chptr->mode.mode & MODE_INVITEONLY)
        return overrideJoin + ERR_INVITEONLYCHAN;
        
  if (chptr->mode.limit && chptr->users >= chptr->mode.limit)
        return overrideJoin + ERR_CHANNELISFULL;

  if ((chptr->mode.mode & MODE_REGONLY) && !IsAccount(sptr))
        return overrideJoin + ERR_NEEDREGGEDNICK;
        
  if (is_banned(sptr, chptr, NULL))
        return overrideJoin + ERR_BANNEDFROMCHAN;
  
  /*
   * now using compall (above) to test against a whole key ring -Kev
   */
  if (*chptr->mode.key && (EmptyString(key) || compall(chptr->mode.key, key)))
    return overrideJoin + ERR_BADCHANNELKEY;

  if (overrideJoin)     
        return ERR_DONTCHEAT;
        
  return 0;
}

/*
 * Remove bells and commas from channel name
 */
void clean_channelname(char *cn)
{
  int i;

  for (i = 0; cn[i]; i++) {
    if (i >= CHANNELLEN || !IsChannelChar(cn[i])) {
      cn[i] = '\0';
      return;
    }
    if (IsChannelLower(cn[i])) {
      cn[i] = ToLower(cn[i]);
#ifndef FIXME
      /*
       * Remove for .08+
       * toupper(0xd0)
       */
      if ((unsigned char)(cn[i]) == 0xd0)
        cn[i] = (char) 0xf0;
#endif
    }
  }
}

/*
 *  Get Channel block for i (and allocate a new channel
 *  block, if it didn't exists before).
 */
struct Channel *get_channel(struct Client *cptr, char *chname, ChannelGetType flag)
{
  struct Channel *chptr;
  int len;

  if (EmptyString(chname))
    return NULL;

  len = strlen(chname);
  if (MyUser(cptr) && len > CHANNELLEN)
  {
    len = CHANNELLEN;
    *(chname + CHANNELLEN) = '\0';
  }
  if ((chptr = FindChannel(chname)))
    return (chptr);
  if (flag == CGT_CREATE)
  {
    chptr = (struct Channel*) MyMalloc(sizeof(struct Channel) + len);
    assert(0 != chptr);
    ++UserStats.channels;
    memset(chptr, 0, sizeof(struct Channel));
    strcpy(chptr->chname, chname);
    if (GlobalChannelList)
      GlobalChannelList->prev = chptr;
    chptr->prev = NULL;
    chptr->next = GlobalChannelList;
    chptr->creationtime = MyUser(cptr) ? TStime() : (time_t) 0;
    GlobalChannelList = chptr;
    hAddChannel(chptr);
  }
  return chptr;
}

void add_invite(struct Client *cptr, struct Channel *chptr)
{
  struct SLink *inv, **tmp;

  del_invite(cptr, chptr);
  /*
   * Delete last link in chain if the list is max length
   */
  assert(list_length((cli_user(cptr))->invited) == (cli_user(cptr))->invites);
  if ((cli_user(cptr))->invites >= feature_int(FEAT_MAXCHANNELSPERUSER))
    del_invite(cptr, (cli_user(cptr))->invited->value.chptr);
  /*
   * Add client to channel invite list
   */
  inv = make_link();
  inv->value.cptr = cptr;
  inv->next = chptr->invites;
  chptr->invites = inv;
  /*
   * Add channel to the end of the client invite list
   */
  for (tmp = &((cli_user(cptr))->invited); *tmp; tmp = &((*tmp)->next));
  inv = make_link();
  inv->value.chptr = chptr;
  inv->next = NULL;
  (*tmp) = inv;
  (cli_user(cptr))->invites++;
}

/*
 * Delete Invite block from channel invite list and client invite list
 */
void del_invite(struct Client *cptr, struct Channel *chptr)
{
  struct SLink **inv, *tmp;

  for (inv = &(chptr->invites); (tmp = *inv); inv = &tmp->next)
    if (tmp->value.cptr == cptr)
    {
      *inv = tmp->next;
      free_link(tmp);
      tmp = 0;
      (cli_user(cptr))->invites--;
      break;
    }

  for (inv = &((cli_user(cptr))->invited); (tmp = *inv); inv = &tmp->next)
    if (tmp->value.chptr == chptr)
    {
      *inv = tmp->next;
      free_link(tmp);
      tmp = 0;
      break;
    }
}

/* List and skip all channels that are listen */
void list_next_channels(struct Client *cptr, int nr)
{
  struct ListingArgs *args = cli_listing(cptr);
  struct Channel *chptr = args->chptr;
  chptr->mode.mode &= ~MODE_LISTED;
  while (is_listed(chptr) || --nr >= 0)
  {
    for (; chptr; chptr = chptr->next)
    {
      if (!cli_user(cptr) || (!(HasPriv(cptr, PRIV_LIST_CHAN) && IsAnOper(cptr)) && 
          SecretChannel(chptr) && !find_channel_member(cptr, chptr)))
        continue;
      if (chptr->users > args->min_users && chptr->users < args->max_users &&
          chptr->creationtime > args->min_time &&
          chptr->creationtime < args->max_time &&
          (!args->topic_limits || (*chptr->topic &&
          chptr->topic_time > args->min_topic_time &&
          chptr->topic_time < args->max_topic_time)))
      {
        if (ShowChannel(cptr,chptr))
          send_reply(cptr, RPL_LIST, chptr->chname, chptr->users,
                     chptr->topic);
        chptr = chptr->next;
        break;
      }
    }
    if (!chptr)
    {
      MyFree(cli_listing(cptr));
      cli_listing(cptr) = NULL;
      send_reply(cptr, RPL_LISTEND);
      break;
    }
  }
  if (chptr)
  {
    (cli_listing(cptr))->chptr = chptr;
    chptr->mode.mode |= MODE_LISTED;
  }

  update_write(cptr);
}

/*
 * Consider:
 *
 *                     client
 *                       |
 *                       c
 *                       |
 *     X --a--> A --b--> B --d--> D
 *                       |
 *                      who
 *
 * Where `who' is being KICK-ed by a "KICK" message received by server 'A'
 * via 'a', or on server 'B' via either 'b' or 'c', or on server D via 'd'.
 *
 * a) On server A : set CHFL_ZOMBIE for `who' (lp) and pass on the KICK.
 *    Remove the user immediately when no users are left on the channel.
 * b) On server B : remove the user (who/lp) from the channel, send a
 *    PART upstream (to A) and pass on the KICK.
 * c) KICKed by `client'; On server B : remove the user (who/lp) from the
 *    channel, and pass on the KICK.
 * d) On server D : remove the user (who/lp) from the channel, and pass on
 *    the KICK.
 *
 * Note:
 * - Setting the ZOMBIE flag never hurts, we either remove the
 *   client after that or we don't.
 * - The KICK message was already passed on, as should be in all cases.
 * - `who' is removed in all cases except case a) when users are left.
 * - A PART is only sent upstream in case b).
 *
 * 2 aug 97:
 *
 *              6
 *              |
 *  1 --- 2 --- 3 --- 4 --- 5
 *        |           |
 *      kicker       who
 *
 * We also need to turn 'who' into a zombie on servers 1 and 6,
 * because a KICK from 'who' (kicking someone else in that direction)
 * can arrive there afterwards - which should not be bounced itself.
 * Therefore case a) also applies for servers 1 and 6.
 *
 * --Run
 */
void make_zombie(struct Membership* member, struct Client* who, struct Client* cptr,
                 struct Client* sptr, struct Channel* chptr)
{
  assert(0 != member);
  assert(0 != who);
  assert(0 != cptr);
  assert(0 != chptr);

  /* Default for case a): */
  SetZombie(member);

  /* Case b) or c) ?: */
  if (MyUser(who))      /* server 4 */
  {
    if (IsServer(cptr)) /* Case b) ? */
      sendcmdto_one(who, CMD_PART, cptr, "%H", chptr);
    remove_user_from_channel(who, chptr);
    return;
  }
  if (cli_from(who) == cptr)        /* True on servers 1, 5 and 6 */
  {
    struct Client *acptr = IsServer(sptr) ? sptr : (cli_user(sptr))->server;
    for (; acptr != &me; acptr = (cli_serv(acptr))->up)
      if (acptr == (cli_user(who))->server)   /* Case d) (server 5) */
      {
        remove_user_from_channel(who, chptr);
        return;
      }
  }

  /* Case a) (servers 1, 2, 3 and 6) */
  if (channel_all_zombies(chptr))
    remove_user_from_channel(who, chptr);

  /* XXX Can't actually call Debug here; if the channel is all zombies,
   * chptr will no longer exist when we get here.
  Debug((DEBUG_INFO, "%s is now a zombie on %s", who->name, chptr->chname));
  */
}

int number_of_zombies(struct Channel *chptr)
{
  struct Membership* member;
  int                count = 0;

  assert(0 != chptr);
  for (member = chptr->members; member; member = member->next_member) {
    if (IsZombie(member))
      ++count;
  }
  return count;
}

/*
 * This helper function builds an argument string in strptr, consisting
 * of the original string, a space, and str1 and str2 concatenated (if,
 * of course, str2 is not NULL)
 */
static void
build_string(char *strptr, int *strptr_i, const char *str1,
             const char *str2, char c)
{
  if (c)
    strptr[(*strptr_i)++] = c;

  while (*str1)
    strptr[(*strptr_i)++] = *(str1++);

  if (str2)
    while (*str2)
      strptr[(*strptr_i)++] = *(str2++);

  strptr[(*strptr_i)] = '\0';
}

/*
 * This is the workhorse of our ModeBuf suite; this actually generates the
 * output MODE commands, HACK notices, or whatever.  It's pretty complicated.
 */
static int
modebuf_flush_int(struct ModeBuf *mbuf, int all)
{
  /* we only need the flags that don't take args right now */
  static int flags[] = {
/*  MODE_CHANOP,        'o', */
/*  MODE_VOICE,         'v', */
    MODE_PRIVATE,       'p',
    MODE_SECRET,        's',
    MODE_MODERATED,     'm',
    MODE_TOPICLIMIT,    't',
    MODE_INVITEONLY,    'i',
    MODE_NOPRIVMSGS,    'n',
    MODE_REGONLY,       'r',
/*  MODE_KEY,           'k', */
/*  MODE_BAN,           'b', */
/*  MODE_LIMIT,         'l', */
/*  MODE_APASS,         'A', */
/*  MODE_UPASS,         'u', */
    0x0, 0x0
  };
  int i;
  int *flag_p;

  struct Client *app_source; /* where the MODE appears to come from */

  char addbuf[20]; /* accumulates +psmtin, etc. */
  int addbuf_i = 0;
  char rembuf[20]; /* accumulates -psmtin, etc. */
  int rembuf_i = 0;
  char *bufptr; /* we make use of indirection to simplify the code */
  int *bufptr_i;

  char addstr[BUFSIZE]; /* accumulates MODE parameters to add */
  int addstr_i;
  char remstr[BUFSIZE]; /* accumulates MODE parameters to remove */
  int remstr_i;
  char *strptr; /* more indirection to simplify the code */
  int *strptr_i;

  int totalbuflen = BUFSIZE - 200; /* fuzz factor -- don't overrun buffer! */
  int tmp;

  char limitbuf[20]; /* convert limits to strings */

  unsigned int limitdel = MODE_LIMIT;

  assert(0 != mbuf);

  /* If the ModeBuf is empty, we have nothing to do */
  if (mbuf->mb_add == 0 && mbuf->mb_rem == 0 && mbuf->mb_count == 0)
    return 0;

  /* Ok, if we were given the OPMODE flag, or its a server, hide the source.
   */
  if (mbuf->mb_dest & MODEBUF_DEST_OPMODE || IsServer(mbuf->mb_source))
    app_source = &me;
  else
    app_source = mbuf->mb_source;

  /*
   * Account for user we're bouncing; we have to get it in on the first
   * bounced MODE, or we could have problems
   */
  if (mbuf->mb_dest & MODEBUF_DEST_DEOP)
    totalbuflen -= 6; /* numeric nick == 5, plus one space */

  /* Calculate the simple flags */
  for (flag_p = flags; flag_p[0]; flag_p += 2) {
    if (*flag_p & mbuf->mb_add)
      addbuf[addbuf_i++] = flag_p[1];
    else if (*flag_p & mbuf->mb_rem)
      rembuf[rembuf_i++] = flag_p[1];
  }

  /* Now go through the modes with arguments... */
  for (i = 0; i < mbuf->mb_count; i++) {
    if (MB_TYPE(mbuf, i) & MODE_ADD) { /* adding or removing? */
      bufptr = addbuf;
      bufptr_i = &addbuf_i;
    } else {
      bufptr = rembuf;
      bufptr_i = &rembuf_i;
    }

    if (MB_TYPE(mbuf, i) & (MODE_CHANOP | MODE_VOICE)) {
      tmp = strlen(cli_name(MB_CLIENT(mbuf, i)));

      if ((totalbuflen - IRCD_MAX(5, tmp)) <= 0) /* don't overflow buffer */
        MB_TYPE(mbuf, i) |= MODE_SAVE; /* save for later */
      else {
        bufptr[(*bufptr_i)++] = MB_TYPE(mbuf, i) & MODE_CHANOP ? 'o' : 'v';
        totalbuflen -= IRCD_MAX(5, tmp) + 1;
      }
    } else if (MB_TYPE(mbuf, i) & (MODE_BAN | MODE_APASS | MODE_UPASS)) {
      tmp = strlen(MB_STRING(mbuf, i));

      if ((totalbuflen - tmp) <= 0) /* don't overflow buffer */
        MB_TYPE(mbuf, i) |= MODE_SAVE; /* save for later */
      else {
        char mode_char;
        switch(MB_TYPE(mbuf, i) & (MODE_BAN | MODE_APASS | MODE_UPASS))
        {
          case MODE_APASS:
            mode_char = 'A';
            break;
          case MODE_UPASS:
            mode_char = 'u';
            break;
          default:
            mode_char = 'b';
            break;
        }
        bufptr[(*bufptr_i)++] = mode_char;
        totalbuflen -= tmp + 1;
      }
    } else if (MB_TYPE(mbuf, i) & MODE_KEY) {
      tmp = (mbuf->mb_dest & MODEBUF_DEST_NOKEY ? 1 :
             strlen(MB_STRING(mbuf, i)));

      if ((totalbuflen - tmp) <= 0) /* don't overflow buffer */
        MB_TYPE(mbuf, i) |= MODE_SAVE; /* save for later */
      else {
        bufptr[(*bufptr_i)++] = 'k';
        totalbuflen -= tmp + 1;
      }
    } else if (MB_TYPE(mbuf, i) & MODE_LIMIT) {
      /* if it's a limit, we also format the number */
      ircd_snprintf(0, limitbuf, sizeof(limitbuf), "%u", MB_UINT(mbuf, i));

      tmp = strlen(limitbuf);

      if ((totalbuflen - tmp) <= 0) /* don't overflow buffer */
        MB_TYPE(mbuf, i) |= MODE_SAVE; /* save for later */
      else {
        bufptr[(*bufptr_i)++] = 'l';
        totalbuflen -= tmp + 1;
      }
    }
  }

  /* terminate the mode strings */
  addbuf[addbuf_i] = '\0';
  rembuf[rembuf_i] = '\0';

  /* If we're building a user visible MODE or HACK... */
  if (mbuf->mb_dest & (MODEBUF_DEST_CHANNEL | MODEBUF_DEST_HACK2 |
                       MODEBUF_DEST_HACK3   | MODEBUF_DEST_HACK4 |
                       MODEBUF_DEST_LOG)) {
    /* Set up the parameter strings */
    addstr[0] = '\0';
    addstr_i = 0;
    remstr[0] = '\0';
    remstr_i = 0;

    for (i = 0; i < mbuf->mb_count; i++) {
      if (MB_TYPE(mbuf, i) & MODE_SAVE)
        continue;

      if (MB_TYPE(mbuf, i) & MODE_ADD) { /* adding or removing? */
        strptr = addstr;
        strptr_i = &addstr_i;
      } else {
        strptr = remstr;
        strptr_i = &remstr_i;
      }

      /* deal with clients... */
      if (MB_TYPE(mbuf, i) & (MODE_CHANOP | MODE_VOICE))
        build_string(strptr, strptr_i, cli_name(MB_CLIENT(mbuf, i)), 0, ' ');

      /* deal with bans... */
      else if (MB_TYPE(mbuf, i) & MODE_BAN)
        build_string(strptr, strptr_i, MB_STRING(mbuf, i), 0, ' ');

      /* deal with keys... */
      else if (MB_TYPE(mbuf, i) & MODE_KEY)
        build_string(strptr, strptr_i, mbuf->mb_dest & MODEBUF_DEST_NOKEY ?
                     "*" : MB_STRING(mbuf, i), 0, ' ');

      /* deal with invisible passwords */
      else if (MB_TYPE(mbuf, i) & (MODE_APASS | MODE_UPASS))
        build_string(strptr, strptr_i, "*", 0, ' ');

      /*
       * deal with limit; note we cannot include the limit parameter if we're
       * removing it
       */
      else if ((MB_TYPE(mbuf, i) & (MODE_ADD | MODE_LIMIT)) ==
               (MODE_ADD | MODE_LIMIT))
        build_string(strptr, strptr_i, limitbuf, 0, ' ');
    }

    /* send the messages off to their destination */
    if (mbuf->mb_dest & MODEBUF_DEST_HACK2)
      sendto_opmask_butone(0, SNO_HACK2, "HACK(2): %s MODE %s %s%s%s%s%s%s "
                           "[%Tu]",
                           cli_name(feature_bool(FEAT_HIS_SNOTICES) ?
                                    mbuf->mb_source : app_source),
                           mbuf->mb_channel->chname,
                           rembuf_i ? "-" : "", rembuf, addbuf_i ? "+" : "",
                           addbuf, remstr, addstr,
                           mbuf->mb_channel->creationtime);

    if (mbuf->mb_dest & MODEBUF_DEST_HACK3)
      sendto_opmask_butone(0, SNO_HACK3, "BOUNCE or HACK(3): %s MODE %s "
                           "%s%s%s%s%s%s [%Tu]",
                           cli_name(feature_bool(FEAT_HIS_SNOTICES) ? 
                                    mbuf->mb_source : app_source),
                           mbuf->mb_channel->chname, rembuf_i ? "-" : "",
                           rembuf, addbuf_i ? "+" : "", addbuf, remstr, addstr,
                           mbuf->mb_channel->creationtime);

    if (mbuf->mb_dest & MODEBUF_DEST_HACK4)
      sendto_opmask_butone(0, SNO_HACK4, "HACK(4): %s MODE %s %s%s%s%s%s%s "
                           "[%Tu]",
#ifdef HEAD_IN_SAND_SNOTICES
                           cli_name(mbuf->mb_source),
#else
                           cli_name(app_source),
#endif
                           mbuf->mb_channel->chname,
                           rembuf_i ? "-" : "", rembuf, addbuf_i ? "+" : "",
                           addbuf, remstr, addstr,
                           mbuf->mb_channel->creationtime);

    if (mbuf->mb_dest & MODEBUF_DEST_LOG)
      log_write(LS_OPERMODE, L_INFO, LOG_NOSNOTICE,
                "%#C OPMODE %H %s%s%s%s%s%s", mbuf->mb_source,
                mbuf->mb_channel, rembuf_i ? "-" : "", rembuf,
                addbuf_i ? "+" : "", addbuf, remstr, addstr);

    if (mbuf->mb_dest & MODEBUF_DEST_CHANNEL)
      sendcmdto_channel_butserv_butone(app_source, CMD_MODE, mbuf->mb_channel, NULL,
                                "%H %s%s%s%s%s%s", mbuf->mb_channel,
                                rembuf_i ? "-" : "", rembuf,
                                addbuf_i ? "+" : "", addbuf, remstr, addstr);
  }

  /* Now are we supposed to propagate to other servers? */
  if (mbuf->mb_dest & MODEBUF_DEST_SERVER) {
    /* set up parameter string */
    addstr[0] = '\0';
    addstr_i = 0;
    remstr[0] = '\0';
    remstr_i = 0;

    /*
     * limit is supressed if we're removing it; we have to figure out which
     * direction is the direction for it to be removed, though...
     */
    limitdel |= (mbuf->mb_dest & MODEBUF_DEST_HACK2) ? MODE_DEL : MODE_ADD;

    for (i = 0; i < mbuf->mb_count; i++) {
      if (MB_TYPE(mbuf, i) & MODE_SAVE)
        continue;

      if (MB_TYPE(mbuf, i) & MODE_ADD) { /* adding or removing? */
        strptr = addstr;
        strptr_i = &addstr_i;
      } else {
        strptr = remstr;
        strptr_i = &remstr_i;
      }

      /* deal with modes that take clients */
      if (MB_TYPE(mbuf, i) & (MODE_CHANOP | MODE_VOICE))
        build_string(strptr, strptr_i, NumNick(MB_CLIENT(mbuf, i)), ' ');

      /* deal with modes that take strings */
      else if (MB_TYPE(mbuf, i) & (MODE_KEY | MODE_BAN | MODE_APASS | MODE_UPASS))
        build_string(strptr, strptr_i, MB_STRING(mbuf, i), 0, ' ');

      /*
       * deal with the limit.  Logic here is complicated; if HACK2 is set,
       * we're bouncing the mode, so sense is reversed, and we have to
       * include the original limit if it looks like it's being removed
       */
      else if ((MB_TYPE(mbuf, i) & limitdel) == limitdel)
        build_string(strptr, strptr_i, limitbuf, 0, ' ');
    }

    /* we were told to deop the source */
    if (mbuf->mb_dest & MODEBUF_DEST_DEOP) {
      addbuf[addbuf_i++] = 'o'; /* remember, sense is reversed */
      addbuf[addbuf_i] = '\0'; /* terminate the string... */
      build_string(addstr, &addstr_i, NumNick(mbuf->mb_source), ' ');

      /* mark that we've done this, so we don't do it again */
      mbuf->mb_dest &= ~MODEBUF_DEST_DEOP;
    }

    if (mbuf->mb_dest & MODEBUF_DEST_OPMODE) {
      /* If OPMODE was set, we're propagating the mode as an OPMODE message */
      sendcmdto_serv_butone(mbuf->mb_source, CMD_OPMODE, mbuf->mb_connect,
                            "%H %s%s%s%s%s%s", mbuf->mb_channel,
                            rembuf_i ? "-" : "", rembuf, addbuf_i ? "+" : "",
                            addbuf, remstr, addstr);
    } else if (mbuf->mb_dest & MODEBUF_DEST_BOUNCE) {
      /*
       * If HACK2 was set, we're bouncing; we send the MODE back to the
       * connection we got it from with the senses reversed and a TS of 0;
       * origin is us
       */
      sendcmdto_one(&me, CMD_MODE, mbuf->mb_connect, "%H %s%s%s%s%s%s %Tu",
                    mbuf->mb_channel, addbuf_i ? "-" : "", addbuf,
                    rembuf_i ? "+" : "", rembuf, addstr, remstr,
                    mbuf->mb_channel->creationtime);
    } else {
      /*
       * We're propagating a normal MODE command to the rest of the network;
       * we send the actual channel TS unless this is a HACK3 or a HACK4
       */
      if (IsServer(mbuf->mb_source))
        sendcmdto_serv_butone(mbuf->mb_source, CMD_MODE, mbuf->mb_connect,
                              "%H %s%s%s%s%s%s %Tu", mbuf->mb_channel,
                              rembuf_i ? "-" : "", rembuf, addbuf_i ? "+" : "",
                              addbuf, remstr, addstr,
                              (mbuf->mb_dest & MODEBUF_DEST_HACK4) ? 0 :
                              mbuf->mb_channel->creationtime);
      else
        sendcmdto_serv_butone(mbuf->mb_source, CMD_MODE, mbuf->mb_connect,
                              "%H %s%s%s%s%s%s", mbuf->mb_channel,
                              rembuf_i ? "-" : "", rembuf, addbuf_i ? "+" : "",
                              addbuf, remstr, addstr);
    }
  }

  /* We've drained the ModeBuf... */
  mbuf->mb_add = 0;
  mbuf->mb_rem = 0;
  mbuf->mb_count = 0;

  /* reinitialize the mode-with-arg slots */
  for (i = 0; i < MAXMODEPARAMS; i++) {
    /* If we saved any, pack them down */
    if (MB_TYPE(mbuf, i) & MODE_SAVE) {
      mbuf->mb_modeargs[mbuf->mb_count] = mbuf->mb_modeargs[i];
      MB_TYPE(mbuf, mbuf->mb_count) &= ~MODE_SAVE; /* don't save anymore */

      if (mbuf->mb_count++ == i) /* don't overwrite our hard work */
        continue;
    } else if (MB_TYPE(mbuf, i) & MODE_FREE)
      MyFree(MB_STRING(mbuf, i)); /* free string if needed */

    MB_TYPE(mbuf, i) = 0;
    MB_UINT(mbuf, i) = 0;
  }

  /* If we're supposed to flush it all, do so--all hail tail recursion */
  if (all && mbuf->mb_count)
    return modebuf_flush_int(mbuf, 1);

  return 0;
}

/*
 * This routine just initializes a ModeBuf structure with the information
 * needed and the options given.
 */
void
modebuf_init(struct ModeBuf *mbuf, struct Client *source,
             struct Client *connect, struct Channel *chan, unsigned int dest)
{
  int i;

  assert(0 != mbuf);
  assert(0 != source);
  assert(0 != chan);
  assert(0 != dest);

  if (IsLocalChannel(chan->chname)) dest &= ~MODEBUF_DEST_SERVER;

  mbuf->mb_add = 0;
  mbuf->mb_rem = 0;
  mbuf->mb_source = source;
  mbuf->mb_connect = connect;
  mbuf->mb_channel = chan;
  mbuf->mb_dest = dest;
  mbuf->mb_count = 0;

  /* clear each mode-with-parameter slot */
  for (i = 0; i < MAXMODEPARAMS; i++) {
    MB_TYPE(mbuf, i) = 0;
    MB_UINT(mbuf, i) = 0;
  }
}

/*
 * This routine simply adds modes to be added or deleted; do a binary OR
 * with either MODE_ADD or MODE_DEL
 */
void
modebuf_mode(struct ModeBuf *mbuf, unsigned int mode)
{
  assert(0 != mbuf);
  assert(0 != (mode & (MODE_ADD | MODE_DEL)));

  mode &= (MODE_ADD | MODE_DEL | MODE_PRIVATE | MODE_SECRET | MODE_MODERATED |
           MODE_TOPICLIMIT | MODE_INVITEONLY | MODE_NOPRIVMSGS | MODE_REGONLY);

  if (!(mode & ~(MODE_ADD | MODE_DEL))) /* don't add empty modes... */
    return;

  if (mode & MODE_ADD) {
    mbuf->mb_rem &= ~mode;
    mbuf->mb_add |= mode;
  } else {
    mbuf->mb_add &= ~mode;
    mbuf->mb_rem |= mode;
  }
}

/*
 * This routine adds a mode to be added or deleted that takes a unsigned
 * int parameter; mode may *only* be the relevant mode flag ORed with one
 * of MODE_ADD or MODE_DEL
 */
void
modebuf_mode_uint(struct ModeBuf *mbuf, unsigned int mode, unsigned int uint)
{
  assert(0 != mbuf);
  assert(0 != (mode & (MODE_ADD | MODE_DEL)));

  MB_TYPE(mbuf, mbuf->mb_count) = mode;
  MB_UINT(mbuf, mbuf->mb_count) = uint;

  /* when we've reached the maximal count, flush the buffer */
  if (++mbuf->mb_count >=
      (MAXMODEPARAMS - (mbuf->mb_dest & MODEBUF_DEST_DEOP ? 1 : 0)))
    modebuf_flush_int(mbuf, 0);
}

/*
 * This routine adds a mode to be added or deleted that takes a string
 * parameter; mode may *only* be the relevant mode flag ORed with one of
 * MODE_ADD or MODE_DEL
 */
void
modebuf_mode_string(struct ModeBuf *mbuf, unsigned int mode, char *string,
                    int free)
{
  assert(0 != mbuf);
  assert(0 != (mode & (MODE_ADD | MODE_DEL)));

  MB_TYPE(mbuf, mbuf->mb_count) = mode | (free ? MODE_FREE : 0);
  MB_STRING(mbuf, mbuf->mb_count) = string;

  /* when we've reached the maximal count, flush the buffer */
  if (++mbuf->mb_count >=
      (MAXMODEPARAMS - (mbuf->mb_dest & MODEBUF_DEST_DEOP ? 1 : 0)))
    modebuf_flush_int(mbuf, 0);
}

/*
 * This routine adds a mode to be added or deleted that takes a client
 * parameter; mode may *only* be the relevant mode flag ORed with one of
 * MODE_ADD or MODE_DEL
 */
void
modebuf_mode_client(struct ModeBuf *mbuf, unsigned int mode,
                    struct Client *client)
{
  assert(0 != mbuf);
  assert(0 != (mode & (MODE_ADD | MODE_DEL)));

  MB_TYPE(mbuf, mbuf->mb_count) = mode;
  MB_CLIENT(mbuf, mbuf->mb_count) = client;

  /* when we've reached the maximal count, flush the buffer */
  if (++mbuf->mb_count >=
      (MAXMODEPARAMS - (mbuf->mb_dest & MODEBUF_DEST_DEOP ? 1 : 0)))
    modebuf_flush_int(mbuf, 0);
}

/*
 * This is the exported binding for modebuf_flush()
 */
int
modebuf_flush(struct ModeBuf *mbuf)
{
  return modebuf_flush_int(mbuf, 1);
}

/*
 * This extracts the simple modes contained in mbuf
 */
void
modebuf_extract(struct ModeBuf *mbuf, char *buf)
{
  static int flags[] = {
/*  MODE_CHANOP,        'o', */
/*  MODE_VOICE,         'v', */
    MODE_PRIVATE,       'p',
    MODE_SECRET,        's',
    MODE_MODERATED,     'm',
    MODE_TOPICLIMIT,    't',
    MODE_INVITEONLY,    'i',
    MODE_NOPRIVMSGS,    'n',
    MODE_KEY,           'k',
    MODE_APASS,         'A',
    MODE_UPASS,         'u',
/*  MODE_BAN,           'b', */
    MODE_LIMIT,         'l',
    MODE_REGONLY,       'r',
    0x0, 0x0
  };
  unsigned int add;
  int i, bufpos = 0, len;
  int *flag_p;
  char *key = 0, limitbuf[20];
  char *apass = 0, *upass = 0;

  assert(0 != mbuf);
  assert(0 != buf);

  buf[0] = '\0';

  add = mbuf->mb_add;

  for (i = 0; i < mbuf->mb_count; i++) { /* find keys and limits */
    if (MB_TYPE(mbuf, i) & MODE_ADD) {
      add |= MB_TYPE(mbuf, i) & (MODE_KEY | MODE_LIMIT | MODE_APASS | MODE_UPASS);

      if (MB_TYPE(mbuf, i) & MODE_KEY) /* keep strings */
        key = MB_STRING(mbuf, i);
      else if (MB_TYPE(mbuf, i) & MODE_LIMIT)
        ircd_snprintf(0, limitbuf, sizeof(limitbuf), "%u", MB_UINT(mbuf, i));
      else if (MB_TYPE(mbuf, i) & MODE_UPASS)
        upass = MB_STRING(mbuf, i);
      else if (MB_TYPE(mbuf, i) & MODE_APASS)
        apass = MB_STRING(mbuf, i);
    }
  }

  if (!add)
    return;

  buf[bufpos++] = '+'; /* start building buffer */

  for (flag_p = flags; flag_p[0]; flag_p += 2)
    if (*flag_p & add)
      buf[bufpos++] = flag_p[1];

  for (i = 0, len = bufpos; i < len; i++) {
    if (buf[i] == 'k')
      build_string(buf, &bufpos, key, 0, ' ');
    else if (buf[i] == 'l')
      build_string(buf, &bufpos, limitbuf, 0, ' ');
    else if (buf[i] == 'u')
      build_string(buf, &bufpos, upass, 0, ' ');
    else if (buf[i] == 'A')
      build_string(buf, &bufpos, apass, 0, ' ');
  }

  buf[bufpos] = '\0';

  return;
}

/*
 * Simple function to invalidate bans
 */
void
mode_ban_invalidate(struct Channel *chan)
{
  struct Membership *member;

  for (member = chan->members; member; member = member->next_member)
    ClearBanValid(member);
}

/*
 * Simple function to drop invite structures
 */
void
mode_invite_clear(struct Channel *chan)
{
  while (chan->invites)
    del_invite(chan->invites->value.cptr, chan);
}

/* What we've done for mode_parse so far... */
#define DONE_LIMIT      0x01    /* We've set the limit */
#define DONE_KEY        0x02    /* We've set the key */
#define DONE_BANLIST    0x04    /* We've sent the ban list */
#define DONE_NOTOPER    0x08    /* We've sent a "Not oper" error */
#define DONE_BANCLEAN   0x10    /* We've cleaned bans... */
#define DONE_UPASS      0x20    /* We've set user pass */
#define DONE_APASS      0x40    /* We've set admin pass */

struct ParseState {
  struct ModeBuf *mbuf;
  struct Client *cptr;
  struct Client *sptr;
  struct Channel *chptr;
  struct Membership *member;
  int parc;
  char **parv;
  unsigned int flags;
  unsigned int dir;
  unsigned int done;
  unsigned int add;
  unsigned int del;
  int args_used;
  int max_args;
  int numbans;
  struct SLink banlist[MAXPARA];
  struct {
    unsigned int flag;
    struct Client *client;
  } cli_change[MAXPARA];
};

/*
 * Here's a helper function to deal with sending along "Not oper" or
 * "Not member" messages
 */
static void
send_notoper(struct ParseState *state)
{
  if (state->done & DONE_NOTOPER)
    return;

  send_reply(state->sptr, (state->flags & MODE_PARSE_NOTOPER) ?
             ERR_CHANOPRIVSNEEDED : ERR_NOTONCHANNEL, state->chptr->chname);

  state->done |= DONE_NOTOPER;
}

/*
 * Helper function to convert limits
 */
static void
mode_parse_limit(struct ParseState *state, int *flag_p)
{
  unsigned int t_limit;

  if (state->dir == MODE_ADD) { /* convert arg only if adding limit */
    if (MyUser(state->sptr) && state->max_args <= 0) /* too many args? */
      return;

    if (state->parc <= 0) { /* warn if not enough args */
      if (MyUser(state->sptr))
        need_more_params(state->sptr, "MODE +l");
      return;
    }

    t_limit = strtoul(state->parv[state->args_used++], 0, 10); /* grab arg */
    state->parc--;
    state->max_args--;

    if (!(state->flags & MODE_PARSE_WIPEOUT) &&
        (!t_limit || t_limit == state->chptr->mode.limit))
      return;
  } else
    t_limit = state->chptr->mode.limit;

  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  if (state->done & DONE_LIMIT) /* allow limit to be set only once */
    return;
  state->done |= DONE_LIMIT;

  if (!state->mbuf)
    return;

  modebuf_mode_uint(state->mbuf, state->dir | flag_p[0], t_limit);

  if (state->flags & MODE_PARSE_SET) { /* set the limit */
    if (state->dir & MODE_ADD) {
      state->chptr->mode.mode |= flag_p[0];
      state->chptr->mode.limit = t_limit;
    } else {
      state->chptr->mode.mode &= ~flag_p[0];
      state->chptr->mode.limit = 0;
    }
  }
}

/*
 * Helper function to convert keys
 */
static void
mode_parse_key(struct ParseState *state, int *flag_p)
{
  char *t_str, *s;
  int t_len;

  if (MyUser(state->sptr) && state->max_args <= 0) /* drop if too many args */
    return;

  if (state->parc <= 0) { /* warn if not enough args */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +k" :
                       "MODE -k");
    return;
  }

  t_str = state->parv[state->args_used++]; /* grab arg */
  state->parc--;
  state->max_args--;

  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  if (state->done & DONE_KEY) /* allow key to be set only once */
    return;
  state->done |= DONE_KEY;

  t_len = KEYLEN;

  /* clean up the key string */
  s = t_str;
  while (*++s > ' ' && *s != ':' && --t_len)
    ;
  *s = '\0';

  if (!*t_str) { /* warn if empty */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +k" :
                       "MODE -k");
    return;
  }

  if (!state->mbuf)
    return;

  /* can't add a key if one is set, nor can one remove the wrong key */
  if (!(state->flags & MODE_PARSE_FORCE))
    if ((state->dir == MODE_ADD && *state->chptr->mode.key) ||
        (state->dir == MODE_DEL &&
         ircd_strcmp(state->chptr->mode.key, t_str))) {
      send_reply(state->sptr, ERR_KEYSET, state->chptr->chname);
      return;
    }

  if (!(state->flags & MODE_PARSE_WIPEOUT) && state->dir == MODE_ADD &&
      !ircd_strcmp(state->chptr->mode.key, t_str))
    return; /* no key change */

  if (state->flags & MODE_PARSE_BOUNCE) {
    if (*state->chptr->mode.key) /* reset old key */
      modebuf_mode_string(state->mbuf, MODE_DEL | flag_p[0],
                          state->chptr->mode.key, 0);
    else /* remove new bogus key */
      modebuf_mode_string(state->mbuf, MODE_ADD | flag_p[0], t_str, 0);
  } else /* send new key */
    modebuf_mode_string(state->mbuf, state->dir | flag_p[0], t_str, 0);

  if (state->flags & MODE_PARSE_SET) {
    if (state->dir == MODE_ADD) /* set the new key */
      ircd_strncpy(state->chptr->mode.key, t_str, KEYLEN);
    else /* remove the old key */
      *state->chptr->mode.key = '\0';
  }
}

/*
 * Helper function to convert user passes
 */
static void
mode_parse_upass(struct ParseState *state, int *flag_p)
{
  char *t_str, *s;
  int t_len;

  if (MyUser(state->sptr) && state->max_args <= 0) /* drop if too many args */
    return;

  if (state->parc <= 0) { /* warn if not enough args */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +u" :
                       "MODE -u");
    return;
  }

  t_str = state->parv[state->args_used++]; /* grab arg */
  state->parc--;
  state->max_args--;

  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  /* If they are not the channel manager, they are not allowed to change it */
  if (MyUser(state->sptr) && !IsChannelManager(state->member)) {
    if (*state->chptr->mode.apass) {
      send_reply(state->sptr, ERR_NOTMANAGER, state->chptr->chname,
          "Use /JOIN", state->chptr->chname, "<AdminPass>.");
    } else {
      send_reply(state->sptr, ERR_NOTMANAGER, state->chptr->chname,
          "Re-create the channel.  The channel must be *empty* for",
          TStime() - state->chptr->creationtime >= 171000 ? "48 contiguous hours" : "a minute or two",
          "before it can be recreated.");
    }
    return;
  }
 
  if (state->done & DONE_UPASS) /* allow upass to be set only once */
    return;
  state->done |= DONE_UPASS;

  t_len = PASSLEN + 1;

  /* clean up the upass string */
  s = t_str;
  while (*++s > ' ' && *s != ':' && --t_len)
    ;
  *s = '\0';

  if (!*t_str) { /* warn if empty */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +u" :
                       "MODE -u");
    return;
  }

  if (!state->mbuf)
    return;

  if (!(state->flags & MODE_PARSE_FORCE))
    /* can't add the upass while apass is not set */
    if (state->dir == MODE_ADD && !*state->chptr->mode.apass) {
      send_reply(state->sptr, ERR_UPASSNOTSET, state->chptr->chname, state->chptr->chname);
      return;
    }
    /* can't add a upass if one is set, nor can one remove the wrong upass */
    if ((state->dir == MODE_ADD && *state->chptr->mode.upass) ||
        (state->dir == MODE_DEL &&
         ircd_strcmp(state->chptr->mode.upass, t_str))) {
      send_reply(state->sptr, ERR_KEYSET, state->chptr->chname);
      return;
    }

  if (!(state->flags & MODE_PARSE_WIPEOUT) && state->dir == MODE_ADD &&
      !ircd_strcmp(state->chptr->mode.upass, t_str))
    return; /* no upass change */

  if (state->flags & MODE_PARSE_BOUNCE) {
    if (*state->chptr->mode.upass) /* reset old upass */
      modebuf_mode_string(state->mbuf, MODE_DEL | flag_p[0],
                          state->chptr->mode.upass, 0);
    else /* remove new bogus upass */
      modebuf_mode_string(state->mbuf, MODE_ADD | flag_p[0], t_str, 0);
  } else /* send new upass */
    modebuf_mode_string(state->mbuf, state->dir | flag_p[0], t_str, 0);

  if (state->flags & MODE_PARSE_SET) {
    if (state->dir == MODE_ADD) /* set the new upass */
      ircd_strncpy(state->chptr->mode.upass, t_str, PASSLEN);
    else /* remove the old upass */
      *state->chptr->mode.upass = '\0';
  }
}

/*
 * Helper function to convert admin passes
 */
static void
mode_parse_apass(struct ParseState *state, int *flag_p)
{
  char *t_str, *s;
  int t_len;

  if (MyUser(state->sptr) && state->max_args <= 0) /* drop if too many args */
    return;

  if (state->parc <= 0) { /* warn if not enough args */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +A" :
                       "MODE -A");
    return;
  }

  t_str = state->parv[state->args_used++]; /* grab arg */
  state->parc--;
  state->max_args--;

  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  /* Don't allow to change the Apass if the channel is older than 48 hours. */
  if (TStime() - state->chptr->creationtime >= 172800 && !IsAnOper(state->sptr)) {
    send_reply(state->sptr, ERR_CHANSECURED, state->chptr->chname);
    return;
  }

  /* If they are not the channel manager, they are not allowed to change it */
  if (MyUser(state->sptr) && !IsChannelManager(state->member)) {
    if (*state->chptr->mode.apass) {
      send_reply(state->sptr, ERR_NOTMANAGER, state->chptr->chname,
          "Use /JOIN", state->chptr->chname, "<AdminPass>.");
    } else {
      send_reply(state->sptr, ERR_NOTMANAGER, state->chptr->chname,
          "Re-create the channel.  The channel must be *empty* for",
          "at least a whole minute", "before it can be recreated.");
    }
    return;
  }
 
  if (state->done & DONE_APASS) /* allow apass to be set only once */
    return;
  state->done |= DONE_APASS;

  t_len = PASSLEN + 1;

  /* clean up the apass string */
  s = t_str;
  while (*++s > ' ' && *s != ':' && --t_len)
    ;
  *s = '\0';

  if (!*t_str) { /* warn if empty */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +A" :
                       "MODE -A");
    return;
  }

  if (!state->mbuf)
    return;

  if (!(state->flags & MODE_PARSE_FORCE)) {
    /* can't remove the apass while upass is still set */
    if (state->dir == MODE_DEL && *state->chptr->mode.upass) {
      send_reply(state->sptr, ERR_UPASSSET, state->chptr->chname, state->chptr->chname);
      return;
    }
    /* can't add an apass if one is set, nor can one remove the wrong apass */
    if ((state->dir == MODE_ADD && *state->chptr->mode.apass) ||
        (state->dir == MODE_DEL && ircd_strcmp(state->chptr->mode.apass, t_str))) {
      send_reply(state->sptr, ERR_KEYSET, state->chptr->chname);
      return;
    }
  }

  if (!(state->flags & MODE_PARSE_WIPEOUT) && state->dir == MODE_ADD &&
      !ircd_strcmp(state->chptr->mode.apass, t_str))
    return; /* no apass change */

  if (state->flags & MODE_PARSE_BOUNCE) {
    if (*state->chptr->mode.apass) /* reset old apass */
      modebuf_mode_string(state->mbuf, MODE_DEL | flag_p[0],
                          state->chptr->mode.apass, 0);
    else /* remove new bogus apass */
      modebuf_mode_string(state->mbuf, MODE_ADD | flag_p[0], t_str, 0);
  } else /* send new apass */
    modebuf_mode_string(state->mbuf, state->dir | flag_p[0], t_str, 0);

  if (state->flags & MODE_PARSE_SET) {
    if (state->dir == MODE_ADD) { /* set the new apass */
      /* Make it VERY clear to the user that this is a one-time password */
      ircd_strncpy(state->chptr->mode.apass, t_str, PASSLEN);
      if (MyUser(state->sptr)) {
        send_reply(state->sptr, RPL_APASSWARN,
            "Channel Admin password (+A) set to '", state->chptr->mode.apass, "'. ",
            "Are you SURE you want to use this as Admin password? ",
            "You will NOT be able to change this password anymore once the channel is more than 48 hours old!");
        send_reply(state->sptr, RPL_APASSWARN,
            "Use \"/MODE ", state->chptr->chname, " -A ", state->chptr->mode.apass,
            "\" to remove the password and then immediately set a new one. "
            "IMPORTANT: YOU CANNOT RECOVER THIS PASSWORD, EVER; "
            "WRITE THE PASSWORD DOWN (don't store this rescue password on disk)! "
            "Now set the channel user password (+u).");
      }
    } else { /* remove the old apass */
      *state->chptr->mode.apass = '\0';
      if (MyUser(state->sptr))
        send_reply(state->sptr, RPL_APASSWARN,
            "WARNING: You removed the channel Admin password MODE (+A). ",
            "If you would disconnect or leave the channel without setting a new password then you will ",
            "not be able to set it again and lose ownership of this channel! ",
            "SET A NEW PASSWORD NOW!", "");
    }
  }
}

/*
 * Helper function to convert bans
 */
static void
mode_parse_ban(struct ParseState *state, int *flag_p)
{
  char *t_str, *s;
  struct SLink *ban, *newban = 0;

  if (state->parc <= 0) { /* Not enough args, send ban list */
    if (MyUser(state->sptr) && !(state->done & DONE_BANLIST)) {
      send_ban_list(state->sptr, state->chptr);
      state->done |= DONE_BANLIST;
    }

    return;
  }

  if (MyUser(state->sptr) && state->max_args <= 0) /* drop if too many args */
    return;

  t_str = state->parv[state->args_used++]; /* grab arg */
  state->parc--;
  state->max_args--;

  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  if ((s = strchr(t_str, ' ')))
    *s = '\0';

  if (!*t_str || *t_str == ':') { /* warn if empty */
    if (MyUser(state->sptr))
      need_more_params(state->sptr, state->dir == MODE_ADD ? "MODE +b" :
                       "MODE -b");
    return;
  }

  t_str = collapse(pretty_mask(t_str));

  /* remember the ban for the moment... */
  if (state->dir == MODE_ADD) {
    newban = state->banlist + (state->numbans++);
    newban->next = 0;

    DupString(newban->value.ban.banstr, t_str);
    newban->value.ban.who = cli_name(state->sptr);
    newban->value.ban.when = TStime();

    newban->flags = CHFL_BAN | MODE_ADD;

    if ((s = strrchr(t_str, '@')) && check_if_ipmask(s + 1))
      newban->flags |= CHFL_BAN_IPMASK;
  }

  if (!state->chptr->banlist) {
    state->chptr->banlist = newban; /* add our ban with its flags */
    state->done |= DONE_BANCLEAN;
    return;
  }

  /* Go through all bans */
  for (ban = state->chptr->banlist; ban; ban = ban->next) {
    /* first, clean the ban flags up a bit */
    if (!(state->done & DONE_BANCLEAN))
      /* Note: We're overloading *lots* of bits here; be careful! */
      ban->flags &= ~(MODE_ADD | MODE_DEL | CHFL_BAN_OVERLAPPED);

    /* Bit meanings:
     *
     * MODE_ADD            - Ban was added; if we're bouncing modes,
     *                       then we'll remove it below; otherwise,
     *                       we'll have to allocate a real ban
     *
     * MODE_DEL            - Ban was marked for deletion; if we're
     *                       bouncing modes, we'll have to re-add it,
     *                       otherwise, we'll have to remove it
     *
     * CHFL_BAN_OVERLAPPED - The ban we added turns out to overlap
     *                       with a ban already set; if we're
     *                       bouncing modes, we'll have to bounce
     *                       this one; otherwise, we'll just ignore
     *                       it when we process added bans
     */

    if (state->dir == MODE_DEL && !ircd_strcmp(ban->value.ban.banstr, t_str)) {
      ban->flags |= MODE_DEL; /* delete one ban */

      if (state->done & DONE_BANCLEAN) /* If we're cleaning, finish */
        break;
    } else if (state->dir == MODE_ADD) {
      /* if the ban already exists, don't worry about it */
      if (!ircd_strcmp(ban->value.ban.banstr, t_str)) {
        newban->flags &= ~MODE_ADD; /* don't add ban at all */
        MyFree(newban->value.ban.banstr); /* stopper a leak */
        state->numbans--; /* deallocate last ban */
        if (state->done & DONE_BANCLEAN) /* If we're cleaning, finish */
          break;
      } else if (!mmatch(ban->value.ban.banstr, t_str)) {
        if (!(ban->flags & MODE_DEL))
          newban->flags |= CHFL_BAN_OVERLAPPED; /* our ban overlaps */
      } else if (!mmatch(t_str, ban->value.ban.banstr))
        ban->flags |= MODE_DEL; /* mark ban for deletion: overlapping */

      if (!ban->next && (newban->flags & MODE_ADD))
      {
        ban->next = newban; /* add our ban with its flags */
        break; /* get out of loop */
      }
    }
  }
  state->done |= DONE_BANCLEAN;
}

/*
 * This is the bottom half of the ban processor
 */
static void
mode_process_bans(struct ParseState *state)
{
  struct SLink *ban, *newban, *prevban, *nextban;
  int count = 0;
  int len = 0;
  int banlen;
  int changed = 0;

  for (prevban = 0, ban = state->chptr->banlist; ban; ban = nextban) {
    count++;
    banlen = strlen(ban->value.ban.banstr);
    len += banlen;
    nextban = ban->next;

    if ((ban->flags & (MODE_DEL | MODE_ADD)) == (MODE_DEL | MODE_ADD)) {
      if (prevban)
        prevban->next = 0; /* Break the list; ban isn't a real ban */
      else
        state->chptr->banlist = 0;

      count--;
      len -= banlen;

      MyFree(ban->value.ban.banstr);

      continue;
    } else if (ban->flags & MODE_DEL) { /* Deleted a ban? */
      modebuf_mode_string(state->mbuf, MODE_DEL | MODE_BAN,
                          ban->value.ban.banstr,
                          state->flags & MODE_PARSE_SET);

      if (state->flags & MODE_PARSE_SET) { /* Ok, make it take effect */
        if (prevban) /* clip it out of the list... */
          prevban->next = ban->next;
        else
          state->chptr->banlist = ban->next;

        count--;
        len -= banlen;

        MyFree(ban->value.ban.who);
        free_link(ban);

        changed++;
        continue; /* next ban; keep prevban like it is */
      } else
        ban->flags &= (CHFL_BAN | CHFL_BAN_IPMASK); /* unset other flags */
    } else if (ban->flags & MODE_ADD) { /* adding a ban? */
      if (prevban)
        prevban->next = 0; /* Break the list; ban isn't a real ban */
      else
        state->chptr->banlist = 0;

      /* If we're supposed to ignore it, do so. */
      if (ban->flags & CHFL_BAN_OVERLAPPED &&
          !(state->flags & MODE_PARSE_BOUNCE)) {
        count--;
        len -= banlen;

        MyFree(ban->value.ban.banstr);
      } else {
        if (state->flags & MODE_PARSE_SET && MyUser(state->sptr) &&
            (len > (feature_int(FEAT_AVBANLEN) * feature_int(FEAT_MAXBANS)) ||
             count > feature_int(FEAT_MAXBANS))) {
          send_reply(state->sptr, ERR_BANLISTFULL, state->chptr->chname,
                     ban->value.ban.banstr);
          count--;
          len -= banlen;

          MyFree(ban->value.ban.banstr);
        } else {
          /* add the ban to the buffer */
          modebuf_mode_string(state->mbuf, MODE_ADD | MODE_BAN,
                              ban->value.ban.banstr,
                              !(state->flags & MODE_PARSE_SET));

          if (state->flags & MODE_PARSE_SET) { /* create a new ban */
            newban = make_link();
            newban->value.ban.banstr = ban->value.ban.banstr;
            DupString(newban->value.ban.who, ban->value.ban.who);
            newban->value.ban.when = ban->value.ban.when;
            newban->flags = ban->flags & (CHFL_BAN | CHFL_BAN_IPMASK);

            newban->next = state->chptr->banlist; /* and link it in */
            state->chptr->banlist = newban;

            changed++;
          }
        }
      }
    }

    prevban = ban;
  } /* for (prevban = 0, ban = state->chptr->banlist; ban; ban = nextban) { */

  if (changed) /* if we changed the ban list, we must invalidate the bans */
    mode_ban_invalidate(state->chptr);
}

/*
 * Helper function to process client changes
 */
static void
mode_parse_client(struct ParseState *state, int *flag_p)
{
  char *t_str;
  struct Client *acptr;
  int i;

  if (MyUser(state->sptr) && state->max_args <= 0) /* drop if too many args */
    return;

  if (state->parc <= 0) /* return if not enough args */
    return;

  t_str = state->parv[state->args_used++]; /* grab arg */
  state->parc--;
  state->max_args--;

  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  if (MyUser(state->sptr)) /* find client we're manipulating */
    acptr = find_chasing(state->sptr, t_str, NULL);
  else
    acptr = findNUser(t_str);

  if (!acptr)
    return; /* find_chasing() already reported an error to the user */

  for (i = 0; i < MAXPARA; i++) /* find an element to stick them in */
    if (!state->cli_change[i].flag || (state->cli_change[i].client == acptr &&
                                       state->cli_change[i].flag & flag_p[0]))
      break; /* found a slot */

  /* Store what we're doing to them */
  state->cli_change[i].flag = state->dir | flag_p[0];
  state->cli_change[i].client = acptr;
}

/*
 * Helper function to process the changed client list
 */
static void
mode_process_clients(struct ParseState *state)
{
  int i;
  struct Membership *member;

  for (i = 0; state->cli_change[i].flag; i++) {
    assert(0 != state->cli_change[i].client);

    /* look up member link */
    if (!(member = find_member_link(state->chptr,
                                    state->cli_change[i].client)) ||
        (MyUser(state->sptr) && IsZombie(member))) {
      if (MyUser(state->sptr))
        send_reply(state->sptr, ERR_USERNOTINCHANNEL,
                   cli_name(state->cli_change[i].client),
                   state->chptr->chname);
      continue;
    }

    if ((state->cli_change[i].flag & MODE_ADD &&
         (state->cli_change[i].flag & member->status)) ||
        (state->cli_change[i].flag & MODE_DEL &&
         !(state->cli_change[i].flag & member->status)))
      continue; /* no change made, don't do anything */

    /* see if the deop is allowed */
    if ((state->cli_change[i].flag & (MODE_DEL | MODE_CHANOP)) ==
        (MODE_DEL | MODE_CHANOP)) {
      /* prevent +k users from being deopped */
      if (IsChannelService(state->cli_change[i].client)) {
        if (state->flags & MODE_PARSE_FORCE) /* it was forced */
          sendto_opmask_butone(0, SNO_HACK4, "Deop of +k user on %H by %s",
                               state->chptr,
                               (IsServer(state->sptr) ? cli_name(state->sptr) :
                                cli_name((cli_user(state->sptr))->server)));

        else if (MyUser(state->sptr) && state->flags & MODE_PARSE_SET) {
          send_reply(state->sptr, ERR_ISCHANSERVICE,
                     cli_name(state->cli_change[i].client),
                     state->chptr->chname);
          continue;
        }
      }

      /* check deop for local user */
      if (MyUser(state->sptr)) {

        /* don't allow local opers to be deopped on local channels */
        if (MyUser(state->sptr) &&
            state->cli_change[i].client != state->sptr &&
            IsLocalChannel(state->chptr->chname) &&
            HasPriv(state->cli_change[i].client, PRIV_DEOP_LCHAN)) {
          send_reply(state->sptr, ERR_ISOPERLCHAN,
                     cli_name(state->cli_change[i].client),
                     state->chptr->chname);
          continue;
        }

        if (feature_bool(FEAT_OPLEVELS)) {
        /* don't allow to deop members with an op level that is <= our own level */
        if (state->sptr != state->cli_change[i].client          /* but allow to deop oneself */
                && state->member
                && OpLevel(member) <= OpLevel(state->member)) {
            int equal = (OpLevel(member) == OpLevel(state->member));
            send_reply(state->sptr, ERR_NOTLOWEROPLEVEL,
                       cli_name(state->cli_change[i].client),
                       state->chptr->chname,
                       OpLevel(state->member), OpLevel(member),
                       "deop", equal ? "the same" : "a higher");
          continue;
        }
      }
    }
    }

    /* set op-level of member being opped */
    if ((state->cli_change[i].flag & (MODE_ADD | MODE_CHANOP)) ==
        (MODE_ADD | MODE_CHANOP)) {
      /* If on a channel with upass set, someone with level x gives ops to someone else,
         then that person gets level x-1.  On other channels, where upass is not set,
         the level stays the same. */
      int level_increment = *state->chptr->mode.upass ? 1 : 0;
      /* Someone being opped by a server gets op-level 0 */
      int old_level = (state->member == NULL) ? -level_increment : OpLevel(state->member);
      SetOpLevel(member, old_level == MAXOPLEVEL ? MAXOPLEVEL : (old_level + level_increment));
    }

    /* accumulate the change */
    modebuf_mode_client(state->mbuf, state->cli_change[i].flag,
                        state->cli_change[i].client);

    /* actually effect the change */
    if (state->flags & MODE_PARSE_SET) {
      if (state->cli_change[i].flag & MODE_ADD) {
        member->status |= (state->cli_change[i].flag &
                           (MODE_CHANOP | MODE_VOICE));
        if (state->cli_change[i].flag & MODE_CHANOP)
          ClearDeopped(member);
      } else
        member->status &= ~(state->cli_change[i].flag &
                            (MODE_CHANOP | MODE_VOICE));
    }
  } /* for (i = 0; state->cli_change[i].flags; i++) */
}

/*
 * Helper function to process the simple modes
 */
static void
mode_parse_mode(struct ParseState *state, int *flag_p)
{
  /* If they're not an oper, they can't change modes */
  if (state->flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER)) {
    send_notoper(state);
    return;
  }

  if (!state->mbuf)
    return;

  if (state->dir == MODE_ADD) {
    state->add |= flag_p[0];
    state->del &= ~flag_p[0];

    if (flag_p[0] & MODE_SECRET) {
      state->add &= ~MODE_PRIVATE;
      state->del |= MODE_PRIVATE;
    } else if (flag_p[0] & MODE_PRIVATE) {
      state->add &= ~MODE_SECRET;
      state->del |= MODE_SECRET;
    }
  } else {
    state->add &= ~flag_p[0];
    state->del |= flag_p[0];
  }

  assert(0 == (state->add & state->del));
  assert((MODE_SECRET | MODE_PRIVATE) !=
         (state->add & (MODE_SECRET | MODE_PRIVATE)));
}

/*
 * This routine is intended to parse MODE or OPMODE commands and effect the
 * changes (or just build the bounce buffer).  We pass the starting offset
 * as a 
 */
int
mode_parse(struct ModeBuf *mbuf, struct Client *cptr, struct Client *sptr,
           struct Channel *chptr, int parc, char *parv[], unsigned int flags,
           struct Membership* member)
{
  static int chan_flags[] = {
    MODE_CHANOP,        'o',
    MODE_VOICE,         'v',
    MODE_PRIVATE,       'p',
    MODE_SECRET,        's',
    MODE_MODERATED,     'm',
    MODE_TOPICLIMIT,    't',
    MODE_INVITEONLY,    'i',
    MODE_NOPRIVMSGS,    'n',
    MODE_KEY,           'k',
    MODE_APASS,         'A',
    MODE_UPASS,         'u',
    MODE_BAN,           'b',
    MODE_LIMIT,         'l',
    MODE_REGONLY,       'r',
    MODE_ADD,           '+',
    MODE_DEL,           '-',
    0x0, 0x0
  };
  int i;
  int *flag_p;
  unsigned int t_mode;
  char *modestr;
  struct ParseState state;

  assert(0 != cptr);
  assert(0 != sptr);
  assert(0 != chptr);
  assert(0 != parc);
  assert(0 != parv);

  state.mbuf = mbuf;
  state.cptr = cptr;
  state.sptr = sptr;
  state.chptr = chptr;
  state.member = member;
  state.parc = parc;
  state.parv = parv;
  state.flags = flags;
  state.dir = MODE_ADD;
  state.done = 0;
  state.add = 0;
  state.del = 0;
  state.args_used = 0;
  state.max_args = MAXMODEPARAMS;
  state.numbans = 0;

  for (i = 0; i < MAXPARA; i++) { /* initialize ops/voices arrays */
    state.banlist[i].next = 0;
    state.banlist[i].value.ban.banstr = 0;
    state.banlist[i].value.ban.who = 0;
    state.banlist[i].value.ban.when = 0;
    state.banlist[i].flags = 0;
    state.cli_change[i].flag = 0;
    state.cli_change[i].client = 0;
  }

  modestr = state.parv[state.args_used++];
  state.parc--;

  while (*modestr) {
    for (; *modestr; modestr++) {
      for (flag_p = chan_flags; flag_p[0]; flag_p += 2) /* look up flag */
        if (flag_p[1] == *modestr)
          break;

      if (!flag_p[0]) { /* didn't find it?  complain and continue */
        if (MyUser(state.sptr))
          send_reply(state.sptr, ERR_UNKNOWNMODE, *modestr);
        continue;
      }

      switch (*modestr) {
      case '+': /* switch direction to MODE_ADD */
      case '-': /* switch direction to MODE_DEL */
        state.dir = flag_p[0];
        break;

      case 'l': /* deal with limits */
        mode_parse_limit(&state, flag_p);
        break;

      case 'k': /* deal with keys */
        mode_parse_key(&state, flag_p);
        break;

      case 'A': /* deal with Admin passes */
        if (feature_bool(FEAT_OPLEVELS))
        mode_parse_apass(&state, flag_p);
        break;

      case 'u': /* deal with user passes */
        if (feature_bool(FEAT_OPLEVELS))
        mode_parse_upass(&state, flag_p);
        break;

      case 'b': /* deal with bans */
        mode_parse_ban(&state, flag_p);
        break;

      case 'o': /* deal with ops/voice */
      case 'v':
        mode_parse_client(&state, flag_p);
        break;

      default: /* deal with other modes */
        mode_parse_mode(&state, flag_p);
        break;
      } /* switch (*modestr) */
    } /* for (; *modestr; modestr++) */

    if (state.flags & MODE_PARSE_BURST)
      break; /* don't interpret any more arguments */

    if (state.parc > 0) { /* process next argument in string */
      modestr = state.parv[state.args_used++];
      state.parc--;

      /* is it a TS? */
      if (IsServer(state.sptr) && !state.parc && IsDigit(*modestr)) {
        time_t recv_ts;

        if (!(state.flags & MODE_PARSE_SET))      /* don't set earlier TS if */
          break;                     /* we're then going to bounce the mode! */

        recv_ts = atoi(modestr);

        if (recv_ts && recv_ts < state.chptr->creationtime)
          state.chptr->creationtime = recv_ts; /* respect earlier TS */

        break; /* break out of while loop */
      } else if (state.flags & MODE_PARSE_STRICT ||
                 (MyUser(state.sptr) && state.max_args <= 0)) {
        state.parc++; /* we didn't actually gobble the argument */
        state.args_used--;
        break; /* break out of while loop */
      }
    }
  } /* while (*modestr) */

  /*
   * the rest of the function finishes building resultant MODEs; if the
   * origin isn't a member or an oper, skip it.
   */
  if (!state.mbuf || state.flags & (MODE_PARSE_NOTOPER | MODE_PARSE_NOTMEMBER))
    return state.args_used; /* tell our parent how many args we gobbled */

  t_mode = state.chptr->mode.mode;

  if (state.del & t_mode) { /* delete any modes to be deleted... */
    modebuf_mode(state.mbuf, MODE_DEL | (state.del & t_mode));

    t_mode &= ~state.del;
  }
  if (state.add & ~t_mode) { /* add any modes to be added... */
    modebuf_mode(state.mbuf, MODE_ADD | (state.add & ~t_mode));

    t_mode |= state.add;
  }

  if (state.flags & MODE_PARSE_SET) { /* set the channel modes */
    if ((state.chptr->mode.mode & MODE_INVITEONLY) &&
        !(t_mode & MODE_INVITEONLY))
      mode_invite_clear(state.chptr);

    state.chptr->mode.mode = t_mode;
  }

  if (state.flags & MODE_PARSE_WIPEOUT) {
    if (state.chptr->mode.limit && !(state.done & DONE_LIMIT))
      modebuf_mode_uint(state.mbuf, MODE_DEL | MODE_LIMIT,
                        state.chptr->mode.limit);
    if (*state.chptr->mode.key && !(state.done & DONE_KEY))
      modebuf_mode_string(state.mbuf, MODE_DEL | MODE_KEY,
                          state.chptr->mode.key, 0);
    if (*state.chptr->mode.upass && !(state.done & DONE_UPASS))
      modebuf_mode_string(state.mbuf, MODE_DEL | MODE_UPASS,
                          state.chptr->mode.upass, 0);
    if (*state.chptr->mode.apass && !(state.done & DONE_APASS))
      modebuf_mode_string(state.mbuf, MODE_DEL | MODE_APASS,
                          state.chptr->mode.apass, 0);
  }

  if (state.done & DONE_BANCLEAN) /* process bans */
    mode_process_bans(&state);

  /* process client changes */
  if (state.cli_change[0].flag)
    mode_process_clients(&state);

  return state.args_used; /* tell our parent how many args we gobbled */
}

/*
 * Initialize a join buffer
 */
void
joinbuf_init(struct JoinBuf *jbuf, struct Client *source,
             struct Client *connect, unsigned int type, char *comment,
             time_t create)
{
  int i;

  assert(0 != jbuf);
  assert(0 != source);
  assert(0 != connect);

  jbuf->jb_source = source; /* just initialize struct JoinBuf */
  jbuf->jb_connect = connect;
  jbuf->jb_type = type;
  jbuf->jb_comment = comment;
  jbuf->jb_create = create;
  jbuf->jb_count = 0;
  jbuf->jb_strlen = (((type == JOINBUF_TYPE_JOIN ||
                       type == JOINBUF_TYPE_PART ||
                       type == JOINBUF_TYPE_PARTALL) ?
                      STARTJOINLEN : STARTCREATELEN) +
                     (comment ? strlen(comment) + 2 : 0));

  for (i = 0; i < MAXJOINARGS; i++)
    jbuf->jb_channels[i] = 0;
}

/*
 * Add a channel to the join buffer
 */
void
joinbuf_join(struct JoinBuf *jbuf, struct Channel *chan, unsigned int flags)
{
  unsigned int len;
  int is_local;

  assert(0 != jbuf);

  if (!chan) {
    if (jbuf->jb_type == JOINBUF_TYPE_JOIN)
      sendcmdto_serv_butone(jbuf->jb_source, CMD_JOIN, jbuf->jb_connect, "0");

    return;
  }

  is_local = IsLocalChannel(chan->chname);

  if (jbuf->jb_type == JOINBUF_TYPE_PART ||
      jbuf->jb_type == JOINBUF_TYPE_PARTALL) {
    struct Membership *member = find_member_link(chan, jbuf->jb_source);
    if (IsUserParting(member))
      return;
    SetUserParting(member);

    /* Send notification to channel */
    if (!(flags & CHFL_ZOMBIE))
      sendcmdto_channel_butserv_butone(jbuf->jb_source, CMD_PART, chan, NULL,
                                (flags & CHFL_BANNED || !jbuf->jb_comment) ?
                                ":%H" : "%H :%s", chan, jbuf->jb_comment);
    else if (MyUser(jbuf->jb_source))
      sendcmdto_one(jbuf->jb_source, CMD_PART, jbuf->jb_source,
                    (flags & CHFL_BANNED || !jbuf->jb_comment) ?
                    ":%H" : "%H :%s", chan, jbuf->jb_comment);
    /* XXX: Shouldn't we send a PART here anyway? */
    /* to users on the channel?  Why?  From their POV, the user isn't on
     * the channel anymore anyway.  We don't send to servers until below,
     * when we gang all the channel parts together.  Note that this is
     * exactly the same logic, albeit somewhat more concise, as was in
     * the original m_part.c */

    if (jbuf->jb_type == JOINBUF_TYPE_PARTALL ||
        is_local) /* got to remove user here */
      remove_user_from_channel(jbuf->jb_source, chan);
  } else {
    /* Add user to channel */
    add_user_to_channel(chan, jbuf->jb_source, flags, 0);

    /* send notification to all servers */
    if (jbuf->jb_type != JOINBUF_TYPE_CREATE && !is_local)
      sendcmdto_serv_butone(jbuf->jb_source, CMD_JOIN, jbuf->jb_connect,
                            "%H %Tu", chan, chan->creationtime);

    /* Send the notification to the channel */
    sendcmdto_channel_butserv_butone(jbuf->jb_source, CMD_JOIN, chan, NULL, ":%H", chan);

    /* send an op, too, if needed */
    if (!MyUser(jbuf->jb_source) && jbuf->jb_type == JOINBUF_TYPE_CREATE)
      sendcmdto_channel_butserv_butone(jbuf->jb_source, CMD_MODE, chan, NULL, "%H +o %C",
                                chan, jbuf->jb_source);
  }

  if (jbuf->jb_type == JOINBUF_TYPE_PARTALL ||
      jbuf->jb_type == JOINBUF_TYPE_JOIN || is_local)
    return; /* don't send to remote */

  /* figure out if channel name will cause buffer to be overflowed */
  len = chan ? strlen(chan->chname) + 1 : 2;
  if (jbuf->jb_strlen + len > BUFSIZE)
    joinbuf_flush(jbuf);

  /* add channel to list of channels to send and update counts */
  jbuf->jb_channels[jbuf->jb_count++] = chan;
  jbuf->jb_strlen += len;

  /* if we've used up all slots, flush */
  if (jbuf->jb_count >= MAXJOINARGS)
    joinbuf_flush(jbuf);
}

/*
 * Flush the channel list to remote servers
 */
int
joinbuf_flush(struct JoinBuf *jbuf)
{
  char chanlist[BUFSIZE];
  int chanlist_i = 0;
  int i;

  if (!jbuf->jb_count || jbuf->jb_type == JOINBUF_TYPE_PARTALL ||
      jbuf->jb_type == JOINBUF_TYPE_JOIN)
    return 0; /* no joins to process */

  for (i = 0; i < jbuf->jb_count; i++) { /* build channel list */
    build_string(chanlist, &chanlist_i,
                 jbuf->jb_channels[i] ? jbuf->jb_channels[i]->chname : "0", 0,
                 i == 0 ? '\0' : ',');
    if (JOINBUF_TYPE_PART == jbuf->jb_type)
      /* Remove user from channel */
      remove_user_from_channel(jbuf->jb_source, jbuf->jb_channels[i]);

    jbuf->jb_channels[i] = 0; /* mark slot empty */
  }

  jbuf->jb_count = 0; /* reset base counters */
  jbuf->jb_strlen = ((jbuf->jb_type == JOINBUF_TYPE_PART ?
                      STARTJOINLEN : STARTCREATELEN) +
                     (jbuf->jb_comment ? strlen(jbuf->jb_comment) + 2 : 0));

  /* and send the appropriate command */
  switch (jbuf->jb_type) {
  case JOINBUF_TYPE_CREATE:
    sendcmdto_serv_butone(jbuf->jb_source, CMD_CREATE, jbuf->jb_connect,
                          "%s %Tu", chanlist, jbuf->jb_create);
    break;

  case JOINBUF_TYPE_PART:
    sendcmdto_serv_butone(jbuf->jb_source, CMD_PART, jbuf->jb_connect,
                          jbuf->jb_comment ? "%s :%s" : "%s", chanlist,
                          jbuf->jb_comment);
    break;
  }

  return 0;
}

/* Returns TRUE (1) if client is invited, FALSE (0) if not */
int IsInvited(struct Client* cptr, const void* chptr)
{
  struct SLink *lp;

  for (lp = (cli_user(cptr))->invited; lp; lp = lp->next)
    if (lp->value.chptr == chptr)
      return 1;
  return 0;
}