/* Copyright 2004 Nick Mathewson */
/* See LICENSE for licensing information */
/* $Id$ */

#include "or.h"

#define CONTROL_CMD_ERROR        0x0000
#define CONTROL_CMD_DONE         0x0001
#define CONTROL_CMD_SETCONF      0x0002
#define CONTROL_CMD_GETCONF      0x0003
#define CONTROL_CMD_CONFVALUE    0x0004
#define CONTROL_CMD_SETEVENTS    0x0005
#define CONTROL_CMD_EVENT        0x0006
#define CONTROL_CMD_AUTHENTICATE 0x0007
#define _CONTROL_CMD_MAX_RECOGNIZED 0x0007

#define ERR_UNSPECIFIED             0x0000
#define ERR_UNRECOGNIZED_TYPE       0x0001
#define ERR_UNRECOGNIZED_CONFIG_KEY 0x0002
#define ERR_INVALID_CONFIG_VALUE    0x0003
#define ERR_UNRECOGNIZED_EVENT_CODE 0x0004
#define ERR_UNAUTHORIZED_USER       0x0005
#define ERR_FAILED_AUTHENTICATION   0x0006

#define _EVENT_MIN            0x0001
#define EVENT_CIRCUIT_STATUS  0x0001
#define EVENT_STREAM_STATUS   0x0002
#define EVENT_OR_CONN_STATUS  0x0003
#define EVENT_BANDWIDTH_USED  0x0004
#define EVENT_WARNING         0x0005
#define _EVENT_MAX            0x0005

#define EVENT_IS_INTERESTING(e) (global_event_mask & (1<<(e)))

static const char *CONTROL_COMMANDS[] = {
  "error",
  "done",
  "setconf",
  "getconf",
  "confvalue",
  "setevents",
  "events",
  "authenticate",
};

static uint32_t global_event_mask = 0;

static void update_global_event_mask(void);
static void send_control_message(connection_t *conn, uint16_t type,
                                 uint16_t len, const char *body);
static void send_control_done(connection_t *conn);
static void send_control_error(connection_t *conn, uint16_t error,
                               const char *message);
static void send_control_event(uint16_t event, uint16_t len, const char *body);
static int handle_control_setconf(connection_t *conn, uint16_t len,
                                  const char *body);
static int handle_control_getconf(connection_t *conn, uint16_t len,
                                  const char *body);
static int handle_control_setevents(connection_t *conn, uint16_t len,
                                    const char *body);
static int handle_control_authenticate(connection_t *conn, uint16_t len,
                                       const char *body);

static INLINE const char *
control_cmd_to_string(uint16_t cmd)
{
  return (cmd<=_CONTROL_CMD_MAX_RECOGNIZED) ? CONTROL_COMMANDS[cmd] : "Unknown";
}

static void update_global_event_mask(void)
{
  connection_t **conns;
  int n_conns, i;

  global_event_mask = 0;
  get_connection_array(&conns, &n_conns);
  for (i = 0; i < n_conns; ++i) {
    if (conns[i]->type == CONN_TYPE_CONTROL &&
        conns[i]->state == CONTROL_CONN_STATE_OPEN) {
      global_event_mask |= conns[i]->event_mask;
    }
  }
}

static void
send_control_message(connection_t *conn, uint16_t type, uint16_t len,
                     const char *body)
{
  char buf[4];
  tor_assert(conn);
  tor_assert(len || !body);
  tor_assert(type <= _CONTROL_CMD_MAX_RECOGNIZED);
  set_uint32(buf, htons(len));
  set_uint32(buf+2, htons(type));
  connection_write_to_buf(buf, 4, conn);
  if (len)
    connection_write_to_buf(body, len, conn);
}

static void
send_control_done(connection_t *conn)
{
  send_control_message(conn, CONTROL_CMD_DONE, 0, NULL);
}

static void
send_control_error(connection_t *conn, uint16_t error, const char *message)
{
  char buf[256];
  size_t len;
  set_uint16(buf, htons(error));
  len = strlen(message);
  tor_assert(len < (256-2));
  memcpy(buf+2, message, len);
  send_control_message(conn, CONTROL_CMD_ERROR, len+2, buf);
}

static void
send_control_event(uint16_t event, uint16_t len, const char *body)
{
  connection_t **conns;
  int n_conns, i;

  get_connection_array(&conns, &n_conns);
  for (i = 0; i < n_conns; ++i) {
    if (conns[i]->type == CONN_TYPE_CONTROL &&
        conns[i]->state == CONTROL_CONN_STATE_OPEN &&
        conns[i]->event_mask & (1<<event)) {
      send_control_message(conns[i], CONTROL_CMD_EVENT, len, body);
    }
  }
}

static int 
handle_control_setconf(connection_t *conn, uint16_t len,
                                  const char *body)
{
  /* XXXX009 NM */
  return 0;
}
static int handle_control_getconf(connection_t *conn, uint16_t len,
                                  const char *body)
{
  /* XXXX009 NM */
  return 0;
}
static int handle_control_setevents(connection_t *conn, uint16_t len,
                                    const char *body)
{
  uint16_t event_code;
  uint32_t event_mask = 0;
  if (len % 2) {
    send_control_error(conn, ERR_UNSPECIFIED,
                       "Odd number of bytes in setevents message");
    return 0;
  }

  for (; len; len -= 2, body += 2) {
    event_code = ntohs(get_uint16(body));
    if (event_code < _EVENT_MIN || event_code > _EVENT_MAX) {
      send_control_error(conn, ERR_UNRECOGNIZED_EVENT_CODE,
                         "Unrecognized event code");
      return 0;
    }
    event_mask |= (1 << event_code);
  }

  conn->event_mask = event_mask;

  update_global_event_mask();
  send_control_done(conn);
  return 0;
}
static int handle_control_authenticate(connection_t *conn, uint16_t len,
                                       const char *body)
{
  if (0/* XXXX009 NM */) {
    send_control_done(conn);
    conn->state = CONTROL_CONN_STATE_OPEN;
  } else {
    send_control_error(conn, ERR_FAILED_AUTHENTICATION,"Authentication failed");
  }
  return 0;
}

int connection_control_finished_flushing(connection_t *conn) {
  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_CONTROL);

  connection_stop_writing(conn);
  return 0;
}

int connection_control_process_inbuf(connection_t *conn) {
  uint16_t body_len, command_type;
  char *body;

  tor_assert(conn);
  tor_assert(conn->type == CONN_TYPE_CONTROL);

 again:
  switch(fetch_from_buf_control(conn->inbuf, &body_len, &command_type, &body))
    {
    case -1:
      log_fn(LOG_WARN, "Error in control command. Failing.");
      return -1;
    case 0:
      /* Control command not all here yet. Wait. */
      return 0;
    case 1:
      /* We got a command. Process it. */
      break;
    default:
      tor_assert(0);
    }

  /* We got a command.  If we need authentication, only authentication
   * commands will be considered. */
  if (conn->state == CONTROL_CONN_STATE_NEEDAUTH &&
      command_type != CONTROL_CMD_AUTHENTICATE) {
    log_fn(LOG_WARN, "Rejecting '%s' command; authentication needed.",
           control_cmd_to_string(command_type));
    send_control_error(conn, ERR_UNAUTHORIZED_USER, "Authentication required");
    tor_free(body);
    goto again;
  }

  switch(command_type)
    {
    case CONTROL_CMD_SETCONF:
      if (handle_control_setconf(conn, body_len, body))
        return -1;
      break;
    case CONTROL_CMD_GETCONF:
      if (handle_control_getconf(conn, body_len, body))
        return -1;
      break;
    case CONTROL_CMD_SETEVENTS:
      if (handle_control_setevents(conn, body_len, body))
        return -1;
      break;
    case CONTROL_CMD_AUTHENTICATE:
      if (handle_control_authenticate(conn, body_len, body))
        return -1;
      break;
    case CONTROL_CMD_ERROR:
    case CONTROL_CMD_DONE:
    case CONTROL_CMD_CONFVALUE:
    case CONTROL_CMD_EVENT:
      log_fn(LOG_WARN, "Received client-only '%s' command; ignoring.",
             control_cmd_to_string(command_type));
      send_control_error(conn, ERR_UNRECOGNIZED_TYPE,
                         "Command type only valid from server to tor client");
      break;
    default:
      log_fn(LOG_WARN, "Received unrecognized command type %d; ignoring.",
             (int)command_type);
      send_control_error(conn, ERR_UNRECOGNIZED_TYPE,
                         "Unrecognized command type");
      break;
  }
  tor_free(body);
  goto again; /* There might be more data. */
}

int control_event_circuit_status(circuit_t *circ)
{
  if (!EVENT_IS_INTERESTING(EVENT_CIRCUIT_STATUS))
    return 0;

  /* XXXXX009 NM */

  return 0;
}

int control_event_stream_status(connection_t *conn)
{
  tor_assert(conn->type == CONN_TYPE_AP);

  if (!EVENT_IS_INTERESTING(EVENT_STREAM_STATUS))
    return 0;

  /* XXXXX009 NM */

  return 0;
}

int control_event_or_conn_status(connection_t *conn)
{
  tor_assert(conn->type == CONN_TYPE_OR);

  if (!EVENT_IS_INTERESTING(EVENT_OR_CONN_STATUS))
    return 0;

  /* XXXXX009 NM */

  return 0;
}

int control_event_bandwidth_used(uint32_t n_read, uint32_t n_written)
{
  char buf[8];

  if (!EVENT_IS_INTERESTING(EVENT_BANDWIDTH_USED))
    return 0;

  set_uint32(buf, htonl(n_read));
  set_uint32(buf+4, htonl(n_read));
  send_control_event(EVENT_BANDWIDTH_USED, 8, buf);

  return 0;
}

int control_event_warning(const char *msg)
{
  size_t len;
  if (!EVENT_IS_INTERESTING(EVENT_WARNING))
    return 0;

  len = strlen(msg);
  send_control_event(EVENT_WARNING, len+1, msg);

  return 0;
}


/*
  Local Variabls:
  mode:c
  indent-tabs-mode:nil
  c-basic-offset:2
  End:
*/