Example #1
0
/** Callback for uping listener socket.
 * Reads a uping from the socket and respond, but not more than 10
 * times per second.
 * @param[in] ev I/O event for uping socket.
 */
static void uping_echo_callback(struct Event* ev)
{
  struct Socket      *sock;
  struct irc_sockaddr from;
  unsigned int       len = 0;
  static time_t      last = 0;
  static int         counter = 0;
  char               buf[BUFSIZE + 1];

  assert(ev_type(ev) == ET_READ || ev_type(ev) == ET_ERROR);
  sock = ev_socket(ev);
  assert(sock == &upingSock_v4 || sock == &upingSock_v6);

  Debug((DEBUG_DEBUG, "UPING: uping_echo"));

  if (IO_SUCCESS != os_recvfrom_nonb(s_fd(sock), buf, BUFSIZE, &len, &from))
    return;
  /*
   * count em even if we're getting flooded so we can tell we're getting
   * flooded.
   */
  ++ServerStats->uping_recv;
  if (len < 19)
    return;
  else if (CurrentTime != last) {
    counter = 0;
    last = CurrentTime;
  } else if (++counter > 10)
    return;
  os_sendto_nonb(s_fd(sock), buf, len, NULL, 0, &from);
}
Example #2
0
/** Callback for socket activity on an outbound uping socket.
 * @param[in] ev I/O event for socket.
 */
static void uping_read_callback(struct Event* ev)
{
  struct UPing *pptr;

  assert(0 != ev_socket(ev));
  assert(0 != s_data(ev_socket(ev)));

  pptr = (struct UPing*) s_data(ev_socket(ev));

  Debug((DEBUG_SEND, "uping_read_callback called, %p (%d)", pptr,
	 ev_type(ev)));

  if (ev_type(ev) == ET_DESTROY) { /* being destroyed */
    pptr->freeable &= ~UPING_PENDING_SOCKET;

    if (!pptr->freeable)
      MyFree(pptr); /* done with it, finally */
  } else {
    assert(ev_type(ev) == ET_READ || ev_type(ev) == ET_ERROR);

    uping_read(pptr); /* read uping response */
  }
}
/*
 * auth_sock_callback - called when an event occurs on the socket
 */
static void auth_sock_callback(struct Event* ev)
{
  struct AuthRequest* auth;

  assert(0 != ev_socket(ev));
  assert(0 != s_data(ev_socket(ev)));

  auth = s_data(ev_socket(ev));

  switch (ev_type(ev)) {
  case ET_DESTROY: /* being destroyed */
    auth->flags &= ~AM_SOCKET;

    if (!(auth->flags & AM_FREE_MASK)) {
      Debug((DEBUG_LIST, "Freeing auth from sock callback; %p [%p]", auth,
	     ev_socket(ev)));
      MyFree(auth); /* done with it finally */
    }
    break;

  case ET_CONNECT: /* socket connection completed */
    Debug((DEBUG_LIST, "Connection completed for auth %p [%p]; sending query",
	   auth, ev_socket(ev)));
    socket_state(&auth->socket, SS_CONNECTED);
    send_auth_query(auth);
    break;

  case ET_READ: /* socket is readable */
  case ET_EOF: /* end of file on socket */
  case ET_ERROR: /* error on socket */
    Debug((DEBUG_LIST, "Auth socket %p [%p] readable", auth, ev_socket(ev)));
    read_auth_reply(auth);
    break;

  default:
#ifndef NDEBUG
    abort(); /* unrecognized event */
#endif
    break;
  }
}
Example #4
0
/** Read a 'packet' of data from a connection and process it.  Read in
 * 8k chunks to give a better performance rating (for server
 * connections).  Do some tricky stuff for client connections to make
 * sure they don't do any flooding >:-) -avalon
 * @param cptr Client from which to read data.
 * @param socket_ready If non-zero, more data can be read from the client's socket.
 * @return Positive number on success, zero on connection-fatal failure, negative
 *   if user is killed.
 */
static int read_packet(struct Client *cptr, int socket_ready)
{
  unsigned int dolen = 0;
  unsigned int length = 0;

  if (socket_ready &&
      !(IsUser(cptr) &&
	DBufLength(&(cli_recvQ(cptr))) > feature_uint(FEAT_CLIENT_FLOOD))) {
#if defined(USE_SSL)
    switch (client_recv(cptr, readbuf, sizeof(readbuf), &length)) {
#else
    switch (os_recv_nonb(cli_fd(cptr), readbuf, sizeof(readbuf), &length)) {
#endif
    case IO_SUCCESS:
      if (length)
      {
        cli_lasttime(cptr) = CurrentTime;
        ClearPingSent(cptr);
        ClrFlag(cptr, FLAG_NONL);
        if (cli_lasttime(cptr) > cli_since(cptr))
          cli_since(cptr) = cli_lasttime(cptr);
      }
      break;
    case IO_BLOCKED:
      break;
    case IO_FAILURE:
      cli_error(cptr) = errno;
      /* SetFlag(cptr, FLAG_DEADSOCKET); */
      return 0;
    }
  }

  /*
   * For server connections, we process as many as we can without
   * worrying about the time of day or anything :)
   */
  if (length > 0 && IsServer(cptr))
    return server_dopacket(cptr, readbuf, length);
  else if (length > 0 && (IsHandshake(cptr) || IsConnecting(cptr)))
    return connect_dopacket(cptr, readbuf, length);
  else
  {
    /*
     * Before we even think of parsing what we just read, stick
     * it on the end of the receive queue and do it when its
     * turn comes around.
     */
    if (length > 0 && dbuf_put(cptr, &(cli_recvQ(cptr)), readbuf, length) == 0)
      return exit_client(cptr, cptr, &me, "dbuf_put fail");

    if ((DBufLength(&(cli_recvQ(cptr))) > feature_uint(FEAT_CLIENT_FLOOD))
         && !IsChannelService(cptr))
      return exit_client(cptr, cptr, &me, "Excess Flood");

    while (DBufLength(&(cli_recvQ(cptr))) && !NoNewLine(cptr) &&
           (IsTrusted(cptr) || IsChannelService(cptr) || cli_since(cptr) - CurrentTime < 10))
    {
      dolen = dbuf_getmsg(&(cli_recvQ(cptr)), cli_buffer(cptr), BUFSIZE);
      /*
       * Devious looking...whats it do ? well..if a client
       * sends a *long* message without any CR or LF, then
       * dbuf_getmsg fails and we pull it out using this
       * loop which just gets the next 512 bytes and then
       * deletes the rest of the buffer contents.
       * -avalon
       */
      if (dolen == 0)
      {
        if (DBufLength(&(cli_recvQ(cptr))) < 510)
          SetFlag(cptr, FLAG_NONL);
        else
        {
          /* More than 512 bytes in the line - drop the input and yell
           * at the client.
           */
          DBufClear(&(cli_recvQ(cptr)));
          send_reply(cptr, ERR_INPUTTOOLONG);
        }
      }
      else if (client_dopacket(cptr, dolen) == CPTR_KILLED)
        return CPTR_KILLED;
      /*
       * If it has become registered as a Server
       * then skip the per-message parsing below.
       */
      if (IsHandshake(cptr) || IsServer(cptr))
      {
        while (-1)
        {
          dolen = dbuf_get(&(cli_recvQ(cptr)), readbuf, sizeof(readbuf));
          if (dolen <= 0)
            return 1;
          else if (dolen == 0)
          {
            if (DBufLength(&(cli_recvQ(cptr))) < 510)
              SetFlag(cptr, FLAG_NONL);
            else {
              DBufClear(&(cli_recvQ(cptr)));
              /* send_reply(cptr, ERR_INPUTTOOLONG); */
            }
          }
          else if ((IsServer(cptr) &&
                    server_dopacket(cptr, readbuf, dolen) == CPTR_KILLED) ||
                   (!IsServer(cptr) &&
                    connect_dopacket(cptr, readbuf, dolen) == CPTR_KILLED))
            return CPTR_KILLED;
        }
      }
    }

    /* If there's still data to process, wait 2 seconds first */
    if (DBufLength(&(cli_recvQ(cptr))) && !NoNewLine(cptr) &&
	!t_onqueue(&(cli_proc(cptr))))
    {
      Debug((DEBUG_LIST, "Adding client process timer for %C", cptr));
      cli_freeflag(cptr) |= FREEFLAG_TIMER;
      timer_add(&(cli_proc(cptr)), client_timer_callback, cli_connect(cptr),
		TT_RELATIVE, 2);
    }
  }
  return 1;
}

/** Start a connection to another server.
 * @param aconf Connect block data for target server.
 * @param by Client who requested the connection (if any).
 * @return Non-zero on success; zero on failure.
 */
int connect_server(struct ConfItem* aconf, struct Client* by)
{
  struct Client*   cptr = 0;
  assert(0 != aconf);

  if (aconf->dns_pending) {
    sendto_opmask(0, SNO_OLDSNO, "Server %s connect DNS pending",
                  aconf->name);
    return 0;
  }
  Debug((DEBUG_NOTICE, "Connect to %s[@%s]", aconf->name,
         ircd_ntoa(&aconf->address.addr)));

  if ((cptr = FindClient(aconf->name))) {
    if (IsServer(cptr) || IsMe(cptr)) {
      sendto_opmask(0, SNO_OLDSNO, "Server %s already present from %s",
                    aconf->name, cli_name(cli_from(cptr)));
      if (by && IsUser(by) && !MyUser(by)) {
        sendcmdto_one(&me, CMD_NOTICE, by, "%C :Server %s already present "
                      "from %s", by, aconf->name, cli_name(cli_from(cptr)));
      }
      return 0;
    }
    else if (IsHandshake(cptr) || IsConnecting(cptr)) {
      if (by && IsUser(by)) {
        sendcmdto_one(&me, CMD_NOTICE, by, "%C :Connection to %s already in "
                      "progress", by, cli_name(cptr));
      }
      return 0;
    }
  }
  /*
   * If we don't know the IP# for this host and it is a hostname and
   * not a ip# string, then try and find the appropriate host record.
   */
  if (!irc_in_addr_valid(&aconf->address.addr)
      && !ircd_aton(&aconf->address.addr, aconf->host)) {
    char buf[HOSTLEN + 1];

    host_from_uh(buf, aconf->host, HOSTLEN);
    gethost_byname(buf, connect_dns_callback, aconf);
    aconf->dns_pending = 1;
    return 0;
  }
  cptr = make_client(NULL, STAT_UNKNOWN_SERVER);

  /*
   * Copy these in so we have something for error detection.
   */
  ircd_strncpy(cli_name(cptr), aconf->name, HOSTLEN);
  ircd_strncpy(cli_sockhost(cptr), aconf->host, HOSTLEN);

  /*
   * Attach config entries to client here rather than in
   * completed_connection. This to avoid null pointer references
   */
  attach_confs_byhost(cptr, aconf->host, CONF_SERVER);

  if (!find_conf_byhost(cli_confs(cptr), aconf->host, CONF_SERVER)) {
    sendto_opmask(0, SNO_OLDSNO, "Host %s is not enabled for "
                  "connecting: no Connect block", aconf->name);
    if (by && IsUser(by) && !MyUser(by)) {
      sendcmdto_one(&me, CMD_NOTICE, by, "%C :Connect to host %s failed: no "
                    "Connect block", by, aconf->name);
    }
    det_confs_butmask(cptr, 0);
    free_client(cptr);
    return 0;
  }
  /*
   * attempt to connect to the server in the conf line
   */
  if (!connect_inet(aconf, cptr)) {
    if (by && IsUser(by) && !MyUser(by)) {
      sendcmdto_one(&me, CMD_NOTICE, by, "%C :Couldn't connect to %s", by,
                    cli_name(cptr));
    }
    det_confs_butmask(cptr, 0);
    free_client(cptr);
    return 0;
  }
  /*
   * NOTE: if we're here we have a valid C:Line and the client should
   * have started the connection and stored the remote address/port and
   * ip address name in itself
   *
   * The socket has been connected or connect is in progress.
   */
  make_server(cptr);
  if (by && IsUser(by)) {
    ircd_snprintf(0, cli_serv(cptr)->by, sizeof(cli_serv(cptr)->by), "%s%s",
		  NumNick(by));
    assert(0 == cli_serv(cptr)->user);
    cli_serv(cptr)->user = cli_user(by);
    cli_user(by)->refcnt++;
  }
  else {
    *(cli_serv(cptr))->by = '\0';
    /* strcpy(cptr->serv->by, "Auto"); */
  }
  cli_serv(cptr)->up = &me;
  SetConnecting(cptr);

  if (cli_fd(cptr) > HighestFd)
    HighestFd = cli_fd(cptr);

  LocalClientArray[cli_fd(cptr)] = cptr;

  Count_newunknown(UserStats);
  /* Actually we lie, the connect hasn't succeeded yet, but we have a valid
   * cptr, so we register it now.
   * Maybe these two calls should be merged.
   */
  add_client_to_list(cptr);
  hAddClient(cptr);
/*    nextping = CurrentTime; */

  return (s_state(&cli_socket(cptr)) == SS_CONNECTED) ?
    completed_connection(cptr) : 1;
}

/** Find the real hostname for the host running the server (or one which
 * matches the server's name) and its primary IP#.  Hostname is stored
 * in the client structure passed as a pointer.
 */
void init_server_identity(void)
{
  const struct LocalConf* conf = conf_get_local();
  assert(0 != conf);

  ircd_strncpy(cli_name(&me), conf->name, HOSTLEN);
  SetYXXServerName(&me, conf->numeric);
}

/** Process events on a client socket.
 * @param ev Socket event structure that has a struct Connection as
 *   its associated data.
 */
static void client_sock_callback(struct Event* ev)
{
  struct Client* cptr;
  struct Connection* con;
  char *fmt = "%s";
  char *fallback = 0;

  assert(0 != ev_socket(ev));
  assert(0 != s_data(ev_socket(ev)));

  con = (struct Connection*) s_data(ev_socket(ev));

  assert(0 != con_client(con) || ev_type(ev) == ET_DESTROY);

  cptr = con_client(con);

  assert(0 == cptr || con == cli_connect(cptr));

  switch (ev_type(ev)) {
  case ET_DESTROY:
    con_freeflag(con) &= ~FREEFLAG_SOCKET;

    if (!con_freeflag(con) && !cptr)
      free_connection(con);
#if defined(USE_SSL)
    ssl_free(ev_socket(ev));
#endif
    break;

  case ET_CONNECT: /* socket connection completed */
    if (!completed_connection(cptr) || IsDead(cptr))
      fallback = cli_info(cptr);
    break;

  case ET_ERROR: /* an error occurred */
    fallback = cli_info(cptr);
    cli_error(cptr) = ev_data(ev);
    /* If the OS told us we have a bad file descriptor, we should
     * record that for future reference.
     */
    if (cli_error(cptr) == EBADF)
      cli_fd(cptr) = -1;
    if (s_state(&(con_socket(con))) == SS_CONNECTING) {
      completed_connection(cptr);
      /* for some reason, the os_get_sockerr() in completed_connection()
       * can return 0 even when ev_data(ev) indicates a real error, so
       * re-assign the client error here.
       */
      cli_error(cptr) = ev_data(ev);
      break;
    }
    /*FALLTHROUGH*/
  case ET_EOF: /* end of file on socket */
    Debug((DEBUG_ERROR, "READ ERROR: fd = %d %d", cli_fd(cptr),
	   cli_error(cptr)));
    SetFlag(cptr, FLAG_DEADSOCKET);
    if ((IsServer(cptr) || IsHandshake(cptr)) && cli_error(cptr) == 0) {
      exit_client_msg(cptr, cptr, &me, "Server %s closed the connection (%s)",
		      cli_name(cptr), cli_serv(cptr)->last_error_msg);
      return;
    } else {
      fmt = "Read error: %s";
      fallback = "EOF from client";
    }
    break;

  case ET_WRITE: /* socket is writable */
    ClrFlag(cptr, FLAG_BLOCKED);
    if (cli_listing(cptr) && MsgQLength(&(cli_sendQ(cptr))) < 2048)
      list_next_channels(cptr);
    Debug((DEBUG_SEND, "Sending queued data to %C", cptr));
    send_queued(cptr);
    break;

  case ET_READ: /* socket is readable */
    if (!IsDead(cptr)) {
      Debug((DEBUG_DEBUG, "Reading data from %C", cptr));
      if (read_packet(cptr, 1) == 0) /* error while reading packet */
	fallback = "EOF from client";
    }
    break;

  default:
    assert(0 && "Unrecognized socket event in client_sock_callback()");
    break;
  }

  assert(0 == cptr || 0 == cli_connect(cptr) || con == cli_connect(cptr));

  if (fallback) {
    const char* msg = (cli_error(cptr)) ? strerror(cli_error(cptr)) : fallback;
    if (!msg)
      msg = "Unknown error";
    exit_client_msg(cptr, cptr, &me, fmt, msg);
  }
}

/** Process a timer on client socket.
 * @param ev Timer event that has a struct Connection as its
 * associated data.
 */
static void client_timer_callback(struct Event* ev)
{
  struct Client* cptr;
  struct Connection* con;

  assert(0 != ev_timer(ev));
  assert(0 != t_data(ev_timer(ev)));
  assert(ET_DESTROY == ev_type(ev) || ET_EXPIRE == ev_type(ev));

  con = (struct Connection*) t_data(ev_timer(ev));

  assert(0 != con_client(con) || ev_type(ev) == ET_DESTROY);

  cptr = con_client(con);

  assert(0 == cptr || con == cli_connect(cptr));

  if (ev_type(ev)== ET_DESTROY) {
    con_freeflag(con) &= ~FREEFLAG_TIMER; /* timer has expired... */

    if (!con_freeflag(con) && !cptr)
      free_connection(con); /* client is being destroyed */
  } else {
    Debug((DEBUG_LIST, "Client process timer for %C expired; processing",
	   cptr));
    read_packet(cptr, 0); /* read_packet will re-add timer if needed */
  }

  assert(0 == cptr || 0 == cli_connect(cptr) || con == cli_connect(cptr));
}
Example #5
0
/** Read a DNS reply from the nameserver and process it.
 * @param[in] ev I/O activity event for resolver socket.
 */
static void
res_readreply(struct Event *ev)
{
  struct irc_sockaddr lsin;
  struct Socket *sock;
  char buf[sizeof(HEADER) + MAXPACKET];
  HEADER *header;
  struct reslist *request = NULL;
  unsigned int rc;
  int answer_count;

  assert((ev_socket(ev) == &res_socket_v4) || (ev_socket(ev) == &res_socket_v6));
  sock = ev_socket(ev);

  if (IO_SUCCESS != os_recvfrom_nonb(s_fd(sock), buf, sizeof(buf), &rc, &lsin)
      || (rc <= sizeof(HEADER)))
    return;

  /*
   * check against possibly fake replies
   */
  if (!res_ourserver(&lsin))
    return;

  /*
   * convert DNS reply reader from Network byte order to CPU byte order.
   */
  header = (HEADER *)buf;
  header->ancount = ntohs(header->ancount);
  header->qdcount = ntohs(header->qdcount);
  header->nscount = ntohs(header->nscount);
  header->arcount = ntohs(header->arcount);

  /*
   * response for an id which we have already received an answer for
   * just ignore this response.
   */
  if (0 == (request = find_id(header->id)))
    return;

  if ((header->rcode != NO_ERRORS) || (header->ancount == 0))
  {
    if (SERVFAIL == header->rcode || NXDOMAIN == header->rcode)
    {
        /*
         * If a bad error was returned, we stop here and don't send
         * send any more (no retries granted).
         */
        Debug((DEBUG_DNS, "Request %p has bad response (state %d type %d rcode %d)", request, request->state, request->type, header->rcode));
        (*request->callback)(request->callback_ctx, NULL, NULL);
	rem_request(request);
    }
    else
    {
      /*
       * If we haven't already tried this, and we're looking up AAAA, try A
       * now
       */

      if (request->state == REQ_AAAA && request->type == T_AAAA)
      {
        request->timeout += feature_int(FEAT_IRCD_RES_TIMEOUT);
        resend_query(request);
      }
      else if (request->type == T_PTR && request->state != REQ_INT &&
               !irc_in_addr_is_ipv4(&request->addr))
      {
        request->state = REQ_INT;
        request->timeout += feature_int(FEAT_IRCD_RES_TIMEOUT);
        resend_query(request);
      }
    }

    return;
  }
  /*
   * If this fails there was an error decoding the received packet,
   * try it again and hope it works the next time.
   */
  answer_count = proc_answer(request, header, buf, buf + rc);

  if (answer_count)
  {
    if (request->type == T_PTR)
    {
      if (request->name == NULL)
      {
        /*
         * got a PTR response with no name, something bogus is happening
         * don't bother trying again, the client address doesn't resolve
         */
        Debug((DEBUG_DNS, "Request %p PTR had empty name", request));
        (*request->callback)(request->callback_ctx, NULL, NULL);
        rem_request(request);
        return;
      }

      /*
       * Lookup the 'authoritative' name that we were given for the
       * ip#.
       */
#ifdef IPV6
      if (!irc_in_addr_is_ipv4(&request->addr))
        do_query_name(request->callback, request->callback_ctx, request->name, NULL, T_AAAA);
      else
#endif
      do_query_name(request->callback, request->callback_ctx, request->name, NULL, T_A);
      Debug((DEBUG_DNS, "Request %p switching to forward resolution", request));
      rem_request(request);
    }
    else
    {
      /*
       * got a name and address response, client resolved
       */
      (*request->callback)(request->callback_ctx, &request->addr, request->name);
      Debug((DEBUG_DNS, "Request %p got forward resolution", request));
      rem_request(request);
    }
  }
  else if (!request->sent)
  {
    /* XXX - we got a response for a query we didn't send with a valid id?
     * this should never happen, bail here and leave the client unresolved
     */
    assert(0);

    /* XXX don't leak it */
    Debug((DEBUG_DNS, "Request %p was unexpected(!)", request));
    rem_request(request);
  }
}
Example #6
0
/** Process events on a client socket.
 * @param ev Socket event structure that has a struct Connection as
 *   its associated data.
 */
static void client_sock_callback(struct Event* ev)
{
  struct Client* cptr;
  struct Connection* con;
  char *fmt = "%s";
  char *fallback = 0;

  assert(0 != ev_socket(ev));
  assert(0 != s_data(ev_socket(ev)));

  con = (struct Connection*) s_data(ev_socket(ev));

  assert(0 != con_client(con) || ev_type(ev) == ET_DESTROY);

  cptr = con_client(con);

  assert(0 == cptr || con == cli_connect(cptr));

  switch (ev_type(ev)) {
  case ET_DESTROY:
    con_freeflag(con) &= ~FREEFLAG_SOCKET;

    if (!con_freeflag(con) && !cptr)
      free_connection(con);
    break;

  case ET_CONNECT: /* socket connection completed */
    if (!completed_connection(cptr) || IsDead(cptr))
      fallback = cli_info(cptr);
    break;

  case ET_ERROR: /* an error occurred */
    fallback = cli_info(cptr);
    cli_error(cptr) = ev_data(ev);
    if (s_state(&(con_socket(con))) == SS_CONNECTING) {
      completed_connection(cptr);
      /* for some reason, the os_get_sockerr() in completed_connect()
       * can return 0 even when ev_data(ev) indicates a real error, so
       * re-assign the client error here.
       */
      cli_error(cptr) = ev_data(ev);
      break;
    }
    /*FALLTHROUGH*/
  case ET_EOF: /* end of file on socket */
    Debug((DEBUG_ERROR, "READ ERROR: fd = %d %d", cli_fd(cptr),
	   cli_error(cptr)));
    SetFlag(cptr, FLAG_DEADSOCKET);
    if ((IsServer(cptr) || IsHandshake(cptr)) && cli_error(cptr) == 0) {
      exit_client_msg(cptr, cptr, &me, "Server %s closed the connection (%s)",
		      cli_name(cptr), cli_serv(cptr)->last_error_msg);
      return;
    } else {
      fmt = "Read error: %s";
      fallback = "EOF from client";
    }
    break;

  case ET_WRITE: /* socket is writable */
    ClrFlag(cptr, FLAG_BLOCKED);
    if (cli_listing(cptr) && MsgQLength(&(cli_sendQ(cptr))) < 2048)
      list_next_channels(cptr);
    Debug((DEBUG_SEND, "Sending queued data to %C", cptr));
    send_queued(cptr);
    break;

  case ET_READ: /* socket is readable */
    if (!IsDead(cptr)) {
      Debug((DEBUG_DEBUG, "Reading data from %C", cptr));
      if (read_packet(cptr, 1) == 0) /* error while reading packet */
	fallback = "EOF from client";
    }
    break;

  default:
    assert(0 && "Unrecognized socket event in client_sock_callback()");
    break;
  }

  assert(0 == cptr || 0 == cli_connect(cptr) || con == cli_connect(cptr));

  if (fallback) {
    const char* msg = (cli_error(cptr)) ? strerror(cli_error(cptr)) : fallback;
    if (!msg)
      msg = "Unknown error";
    exit_client_msg(cptr, cptr, &me, fmt, msg);
  }
}