lua_enet.c

Go to the documentation of this file.

// clang-format off
 
#include <stdlib.h>
#include <string.h>
 
// For lua5.2 support, instead we could replace all the luaL_register's with whatever
// lua5.2's equivalent function is, but this is easier so whatever.
#define LUA_COMPAT_MODULE
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"
#include <enet/enet.h>
 
#define check_host(l, idx)\
   *(ENetHost**)luaL_checkudata(l, idx, "enet_host")
 
#define check_peer(l, idx)\
   *(ENetPeer**)luaL_checkudata(l, idx, "enet_peer")

static void parse_address(lua_State *l, const char *addr_str, ENetAddress *address) {
   int host_i = 0, port_i = 0;
   char host_str[128] = {0};
   char port_str[32] = {0};
   int scanning_port = 0;
 
   char *c = (char *)addr_str;
 
   while (*c != 0) {
      if (host_i >= 128 || port_i >= 32 ) luaL_error(l, "Hostname too long");
      if (scanning_port) {
         port_str[port_i++] = *c;
      } else {
         if (*c == ':') {
            scanning_port = 1;
         } else {
            host_str[host_i++] = *c;
         }
      }
      c++;
   }
   host_str[host_i] = '\0';
   port_str[port_i] = '\0';
 
   if (host_i == 0) luaL_error(l, "Failed to parse address");
   if (port_i == 0) luaL_error(l, "Missing port in address");
 
   if (strcmp("*", host_str) == 0) {
      address->host = ENET_HOST_ANY;
   } else {
      if (enet_address_set_host(address, host_str) != 0) {
         luaL_error(l, "Failed to resolve host name");
      }
   }
 
   if (strcmp("*", port_str) == 0) {
      address->port = ENET_PORT_ANY;
   } else {
      address->port = atoi(port_str);
   }
}

size_t find_peer_index (lua_State *l, ENetHost *enet_host, ENetPeer *peer) {
   size_t peer_index;
   for (peer_index = 0; peer_index < enet_host->peerCount; peer_index++) {
      if (peer == &(enet_host->peers[peer_index]))
         return peer_index;
   }
 
   luaL_error (l, "enet: could not find peer id!");
 
   return peer_index;
}
 
static void push_peer(lua_State *l, ENetPeer *peer) {
   // try to find in peer table
   lua_getfield(l, LUA_REGISTRYINDEX, "enet_peers");
   lua_pushlightuserdata(l, peer);
   lua_gettable(l, -2);
 
   if (lua_isnil(l, -1)) {
      // printf("creating new peer\n");
      lua_pop(l, 1);
 
      *(ENetPeer**)lua_newuserdata(l, sizeof(void*)) = peer;
      luaL_getmetatable(l, "enet_peer");
      lua_setmetatable(l, -2);
 
      lua_pushlightuserdata(l, peer);
      lua_pushvalue(l, -2);
 
      lua_settable(l, -4);
   }
   lua_remove(l, -2); // remove enet_peers
}
 
static void push_event(lua_State *l, ENetEvent *event) {
   lua_newtable(l); // event table
 
   if (event->peer) {
      push_peer(l, event->peer);
      lua_setfield(l, -2, "peer");
   }
 
   switch (event->type) {
      case ENET_EVENT_TYPE_CONNECT:
         lua_pushinteger(l, event->data);
         lua_setfield(l, -2, "data");
 
         lua_pushstring(l, "connect");
         break;
      case ENET_EVENT_TYPE_DISCONNECT:
         lua_pushinteger(l, event->data);
         lua_setfield(l, -2, "data");
 
         lua_pushstring(l, "disconnect");
         break;
      case ENET_EVENT_TYPE_RECEIVE:
         lua_pushlstring(l, (const char *)event->packet->data, event->packet->dataLength);
         lua_setfield(l, -2, "data");
 
         lua_pushinteger(l, event->channelID);
         lua_setfield(l, -2, "channel");
 
         lua_pushstring(l, "receive");
 
         enet_packet_destroy(event->packet);
         break;
      case ENET_EVENT_TYPE_NONE:
         lua_pushstring(l, "none");
         break;
   }
 
   lua_setfield(l, -2, "type");
}

static ENetPacket *read_packet(lua_State *l, int idx, enet_uint8 *channel_id) {
   size_t size;
   int argc = lua_gettop(l);
   const void *data = luaL_checklstring(l, idx, &size);
   ENetPacket *packet;
 
   enet_uint32 flags = ENET_PACKET_FLAG_RELIABLE;
   *channel_id = 0;
 
   if (argc >= idx+2 && !lua_isnil(l, idx+2)) {
      const char *flag_str = luaL_checkstring(l, idx+2);
      if (strcmp("unsequenced", flag_str) == 0) {
         flags = ENET_PACKET_FLAG_UNSEQUENCED;
      } else if (strcmp("reliable", flag_str) == 0) {
         flags = ENET_PACKET_FLAG_RELIABLE;
      } else if (strcmp("unreliable", flag_str) == 0) {
         flags = 0;
      } else {
         luaL_error(l, "Unknown packet flag: %s", flag_str);
      }
   }
 
   if (argc >= idx+1 && !lua_isnil(l, idx+1)) {
      *channel_id = luaL_checkint(l, idx+1);
   }
 
   packet = enet_packet_create(data, size, flags);
   if (packet == NULL) {
      luaL_error(l, "Failed to create packet");
   }
 
   return packet;
}

static int host_create(lua_State *l) {
   ENetHost *host;
   size_t peer_count = 64, channel_count = 1;
   enet_uint32 in_bandwidth = 0, out_bandwidth = 0;
 
   int have_address = 1;
   ENetAddress address;
 
   if (lua_gettop(l) == 0 || lua_isnil(l, 1)) {
      have_address = 0;
   } else {
      parse_address(l, luaL_checkstring(l, 1), &address);
   }
 
   switch (lua_gettop(l)) {
      case 5:
         if (!lua_isnil(l, 5)) out_bandwidth = luaL_checkint(l, 5);
         /* fallthrough */
      case 4:
         if (!lua_isnil(l, 4)) in_bandwidth = luaL_checkint(l, 4);
         /* fallthrough */
      case 3:
         if (!lua_isnil(l, 3)) channel_count = luaL_checkint(l, 3);
         /* fallthrough */
      case 2:
         if (!lua_isnil(l, 2)) peer_count = luaL_checkint(l, 2);
   }
 
   // printf("host create, peers=%d, channels=%d, in=%d, out=%d\n",
   //    peer_count, channel_count, in_bandwidth, out_bandwidth);
   host = enet_host_create(have_address ? &address : NULL, peer_count,
         channel_count, in_bandwidth, out_bandwidth);
 
   if (host == NULL) {
      lua_pushnil (l);
      lua_pushstring(l, "enet: failed to create host (already listening?)");
      return 2;
   }
 
   *(ENetHost**)lua_newuserdata(l, sizeof(void*)) = host;
   luaL_getmetatable(l, "enet_host");
   lua_setmetatable(l, -2);
 
   return 1;
}
 
static int linked_version(lua_State *l) {
   lua_pushfstring(l, "%d.%d.%d",
         ENET_VERSION_GET_MAJOR(enet_linked_version()),
         ENET_VERSION_GET_MINOR(enet_linked_version()),
         ENET_VERSION_GET_PATCH(enet_linked_version()));
   return 1;
}

static int host_service(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   ENetEvent event;
   int timeout = 0, out;
 
   if (lua_gettop(l) > 1)
      timeout = luaL_checkint(l, 2);
 
   out = enet_host_service(host, &event, timeout);
   if (out == 0) return 0;
   if (out < 0) return luaL_error(l, "Error during service");
 
   push_event(l, &event);
   return 1;
}

static int host_check_events(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   ENetEvent event;
   int out = enet_host_check_events(host, &event);
   if (out == 0) return 0;
   if (out < 0) return luaL_error(l, "Error checking event");
 
   push_event(l, &event);
   return 1;
}

static int host_compress_with_range_coder(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   int result = enet_host_compress_with_range_coder (host);
   if (result == 0) {
      lua_pushboolean (l, 1);
   } else {
      lua_pushboolean (l, 0);
   }
 
   return 1;
}

static int host_connect(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   ENetAddress address;
   ENetPeer *peer;
 
   enet_uint32 data = 0;
   size_t channel_count = 1;
 
   parse_address(l, luaL_checkstring(l, 2), &address);
 
   switch (lua_gettop(l)) {
      case 4:
         if (!lua_isnil(l, 4)) data = luaL_checkint(l, 4);
         /* fallthrough */
      case 3:
         /* fallthrough */
         if (!lua_isnil(l, 3)) channel_count = luaL_checkint(l, 3);
   }
 
   // printf("host connect, channels=%d, data=%d\n", channel_count, data);
   peer = enet_host_connect(host, &address, channel_count, data);
 
   if (peer == NULL) {
      return luaL_error(l, "Failed to create peer");
   }
 
   push_peer(l, peer);
 
   return 1;
}
 
static int host_flush(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   enet_host_flush(host);
   return 0;
}
 
static int host_broadcast(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   enet_uint8 channel_id;
   ENetPacket *packet = read_packet(l, 2, &channel_id);
   enet_host_broadcast(host, channel_id, packet);
   return 0;
}
 
// Args: limit:number
static int host_channel_limit(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   int limit = luaL_checkint(l, 2);
   enet_host_channel_limit(host, limit);
   return 0;
}
 
static int host_bandwidth_limit(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   enet_uint32 in_bandwidth = luaL_checkint(l, 2);
   enet_uint32 out_bandwidth = luaL_checkint(l, 2);
   enet_host_bandwidth_limit(host, in_bandwidth, out_bandwidth);
   return 0;
}
 
static int host_get_socket_address(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
   ENetAddress address;
   enet_socket_get_address (host->socket, &address);
 
   lua_pushfstring(l, "%d.%d.%d.%d:%d",
         ((address.host) & 0xFF),
         ((address.host >> 8) & 0xFF),
         ((address.host >> 16) & 0xFF),
         (address.host >> 24& 0xFF),
         address.port);
 
   return 1;
}
static int host_total_sent_data(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   lua_pushinteger (l, host->totalSentData);
 
   return 1;
}
 
static int host_total_received_data(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   lua_pushinteger (l, host->totalReceivedData);
 
   return 1;
}
static int host_service_time(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   lua_pushinteger (l, host->serviceTime);
 
   return 1;
}
 
static int host_peer_count(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   lua_pushinteger (l, host->peerCount);
 
   return 1;
}
 
static int host_get_peer(lua_State *l) {
   ENetHost *host = check_host(l, 1);
   if (!host) {
      return luaL_error(l, "Tried to index a nil host!");
   }
 
   size_t peer_index = (size_t) luaL_checkint(l, 2) - 1;
 
   if (peer_index >= host->peerCount) {
      luaL_argerror (l, 2, "Invalid peer index");
   }
 
   ENetPeer *peer = &(host->peers[peer_index]);
 
   push_peer (l, peer);
   return 1;
}
 
static int host_gc(lua_State *l) {
   // We have to manually grab the userdata so that we can set it to NULL.
   ENetHost** host = luaL_checkudata(l, 1, "enet_host");
   // We don't want to crash by destroying a non-existant host.
   if (*host) {
      enet_host_destroy(*host);
   }
   *host = NULL;
   return 0;
}
 
static int peer_tostring(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
   char host_str[128];
   enet_address_get_host_ip(&peer->address, host_str, 128);
 
   lua_pushstring(l, host_str);
   lua_pushstring(l, ":");
   lua_pushinteger(l, peer->address.port);
   lua_concat(l, 3);
   return 1;
}
 
static int peer_ping(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
   enet_peer_ping(peer);
   return 0;
}
 
static int peer_throttle_configure(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   enet_uint32 interval = luaL_checkint(l, 2);
   enet_uint32 acceleration = luaL_checkint(l, 3);
   enet_uint32 deceleration = luaL_checkint(l, 4);
 
   enet_peer_throttle_configure(peer, interval, acceleration, deceleration);
   return 0;
}
 
static int peer_round_trip_time(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   if (lua_gettop(l) > 1) {
      enet_uint32 round_trip_time = luaL_checkint(l, 2);
      peer->roundTripTime = round_trip_time;
   }
 
   lua_pushinteger (l, peer->roundTripTime);
 
   return 1;
}
 
static int peer_last_round_trip_time(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   if (lua_gettop(l) > 1) {
      enet_uint32 round_trip_time = luaL_checkint(l, 2);
      peer->lastRoundTripTime = round_trip_time;
   }
   lua_pushinteger (l, peer->lastRoundTripTime);
 
   return 1;
}
 
static int peer_ping_interval(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   if (lua_gettop(l) > 1) {
      enet_uint32 interval = luaL_checkint(l, 2);
      enet_peer_ping_interval (peer, interval);
   }
 
   lua_pushinteger (l, peer->pingInterval);
 
   return 1;
}
 
static int peer_timeout(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   enet_uint32 timeout_limit = 0;
   enet_uint32 timeout_minimum = 0;
   enet_uint32 timeout_maximum = 0;
 
   switch (lua_gettop(l)) {
      case 4:
         if (!lua_isnil(l, 4)) timeout_maximum = luaL_checkint(l, 4);
         /* fallthrough */
      case 3:
         if (!lua_isnil(l, 3)) timeout_minimum = luaL_checkint(l, 3);
         /* fallthrough */
      case 2:
         if (!lua_isnil(l, 2)) timeout_limit = luaL_checkint(l, 2);
   }
 
   enet_peer_timeout (peer, timeout_limit, timeout_minimum, timeout_maximum);
 
   lua_pushinteger (l, peer->timeoutLimit);
   lua_pushinteger (l, peer->timeoutMinimum);
   lua_pushinteger (l, peer->timeoutMaximum);
 
   return 3;
}
 
static int peer_disconnect(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   enet_uint32 data = lua_gettop(l) > 1 ? luaL_checkint(l, 2) : 0;
   enet_peer_disconnect(peer, data);
   return 0;
}
 
static int peer_disconnect_now(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   enet_uint32 data = lua_gettop(l) > 1 ? luaL_checkint(l, 2) : 0;
   enet_peer_disconnect_now(peer, data);
   return 0;
}
 
static int peer_disconnect_later(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   enet_uint32 data = lua_gettop(l) > 1 ? luaL_checkint(l, 2) : 0;
   enet_peer_disconnect_later(peer, data);
   return 0;
}
 
static int peer_index(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   size_t peer_index = find_peer_index (l, peer->host, peer);
   lua_pushinteger (l, peer_index + 1);
 
   return 1;
}
 
static int peer_state(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   switch (peer->state) {
      case (ENET_PEER_STATE_DISCONNECTED):
         lua_pushstring (l, "disconnected");
         break;
      case (ENET_PEER_STATE_CONNECTING):
         lua_pushstring (l, "connecting");
         break;
      case (ENET_PEER_STATE_ACKNOWLEDGING_CONNECT):
         lua_pushstring (l, "acknowledging_connect");
         break;
      case (ENET_PEER_STATE_CONNECTION_PENDING):
         lua_pushstring (l, "connection_pending");
         break;
      case (ENET_PEER_STATE_CONNECTION_SUCCEEDED):
         lua_pushstring (l, "connection_succeeded");
         break;
      case (ENET_PEER_STATE_CONNECTED):
         lua_pushstring (l, "connected");
         break;
      case (ENET_PEER_STATE_DISCONNECT_LATER):
         lua_pushstring (l, "disconnect_later");
         break;
      case (ENET_PEER_STATE_DISCONNECTING):
         lua_pushstring (l, "disconnecting");
         break;
      case (ENET_PEER_STATE_ACKNOWLEDGING_DISCONNECT):
         lua_pushstring (l, "acknowledging_disconnect");
         break;
      case (ENET_PEER_STATE_ZOMBIE):
         lua_pushstring (l, "zombie");
         break;
      default:
         lua_pushstring (l, "unknown");
   }
 
   return 1;
}
 
static int peer_connect_id(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   lua_pushinteger (l, peer->connectID);
 
   return 1;
}
 
 
static int peer_reset(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
   enet_peer_reset(peer);
   return 0;
}
 
static int peer_receive(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
   ENetPacket *packet;
   enet_uint8 channel_id = 0;
 
   if (lua_gettop(l) > 1) {
      channel_id = luaL_checkint(l, 2);
   }
 
   packet = enet_peer_receive(peer, &channel_id);
   if (packet == NULL) return 0;
 
   lua_pushlstring(l, (const char *)packet->data, packet->dataLength);
   lua_pushinteger(l, channel_id);
 
   enet_packet_destroy(packet);
   return 2;
}
 

static int peer_send(lua_State *l) {
   ENetPeer *peer = check_peer(l, 1);
 
   enet_uint8 channel_id;
   ENetPacket *packet = read_packet(l, 2, &channel_id);
 
   // printf("sending, channel_id=%d\n", channel_id);
   int ret = enet_peer_send(peer, channel_id, packet);
   if (ret < 0) {
      enet_packet_destroy(packet);
   }
 
   lua_pushinteger(l, ret);
 
   return 1;
}
 
static const struct luaL_Reg enet_funcs [] = {
   {"host_create", host_create},
   {"linked_version", linked_version},
   {NULL, NULL}
};
 
static const struct luaL_Reg enet_host_funcs [] = {
   {"service", host_service},
   {"check_events", host_check_events},
   {"compress_with_range_coder", host_compress_with_range_coder},
   {"connect", host_connect},
   {"flush", host_flush},
   {"broadcast", host_broadcast},
   {"channel_limit", host_channel_limit},
   {"bandwidth_limit", host_bandwidth_limit},
   // Since ENetSocket isn't part of enet-lua, we should try to keep
   // naming conventions the same as the rest of the lib.
   {"get_socket_address", host_get_socket_address},
   // We need this function to free up our ports when needed!
   {"destroy", host_gc},
 
   // additional convenience functions (mostly accessors)
   {"total_sent_data", host_total_sent_data},
   {"total_received_data", host_total_received_data},
   {"service_time", host_service_time},
   {"peer_count", host_peer_count},
   {"get_peer", host_get_peer},
   {NULL, NULL}
};
 
static const struct luaL_Reg enet_peer_funcs [] = {
   {"disconnect", peer_disconnect},
   {"disconnect_now", peer_disconnect_now},
   {"disconnect_later", peer_disconnect_later},
   {"reset", peer_reset},
   {"ping", peer_ping},
   {"receive", peer_receive},
   {"send", peer_send},
   {"throttle_configure", peer_throttle_configure},
   {"ping_interval", peer_ping_interval},
   {"timeout", peer_timeout},
 
   // additional convenience functions to member variables
   {"index", peer_index},
   {"state", peer_state},
   {"connect_id", peer_connect_id},
   {"round_trip_time", peer_round_trip_time},
   {"last_round_trip_time", peer_last_round_trip_time},
   {NULL, NULL}
};
 
int luaopen_enet(lua_State *l) {
   enet_initialize();
   atexit(enet_deinitialize);
 
   // create metatables
   luaL_newmetatable(l, "enet_host");
   lua_newtable(l); // index
   luaL_register(l, NULL, enet_host_funcs);
   lua_setfield(l, -2, "__index");
   lua_pushcfunction(l, host_gc);
   lua_setfield(l, -2, "__gc");
 
   luaL_newmetatable(l, "enet_peer");
   lua_newtable(l);
   luaL_register(l, NULL, enet_peer_funcs);
   lua_setfield(l, -2, "__index");
   lua_pushcfunction(l, peer_tostring);
   lua_setfield(l, -2, "__tostring");
 
   // set up peer table
   lua_newtable(l);
 
   lua_newtable(l); // metatable
   lua_pushstring(l, "v");
   lua_setfield(l, -2, "__mode");
   lua_setmetatable(l, -2);
 
   lua_setfield(l, LUA_REGISTRYINDEX, "enet_peers");
 
   luaL_register(l, "enet", enet_funcs);
   return 1;
}