Browse Source

Switch to new HKMP project protocol

Community is focusing work on a new HKMP project different from jngo's.
Update soulmate to use that new protocol instead.
Wolf Clement 2 năm trước cách đây
mục cha
commit
c606d0dd0c
20 tập tin đã thay đổi với 1513 bổ sung671 xóa
  1. 658 4
      LICENSE
  2. 1 1
      README.md
  3. 35 0
      docs/building.md
  4. 3 34
      docs/index.md
  5. 10 0
      docs/protocol.md
  6. 0 56
      src/customknight.c
  7. 0 28
      src/customknight.h
  8. 16 21
      src/http.c
  9. 22 24
      src/main.c
  10. 0 8
      src/misc.h
  11. 24 42
      src/player.c
  12. 41 18
      src/player.h
  13. 277 148
      src/protocol.c
  14. 80 62
      src/protocol.h
  15. 68 16
      src/server.c
  16. 43 12
      src/server.h
  17. 0 141
      src/tcp.c
  18. 0 12
      src/tcp.h
  19. 216 38
      src/udp.c
  20. 19 6
      src/udp.h

+ 658 - 4
LICENSE

@@ -1,7 +1,661 @@
-Copyright (c) 2020 Wolf Clement
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+3 of the GNU General Public License.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU Affero General Public License from time to time.  Such new versions
+will be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU Affero General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU Affero General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU Affero General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<https://www.gnu.org/licenses/>.

+ 1 - 1
README.md

@@ -1,5 +1,5 @@
 # soulmate
 
-A dedicated server for the Hollow Knight multiplayer mod.
+A dedicated server for the [Hollow Knight multiplayer mod](https://github.com/Extremelyd1/HKMP).
 
 For more information, read [the wiki](https://man.sr.ht/~kiwec/soulmate/docs/).

+ 35 - 0
docs/building.md

@@ -0,0 +1,35 @@
+## Building
+
+soulmate requires the following dependencies :
+
+- [libuv](https://libuv.org/)
+
+- [BearSSL](https://bearssl.org/)
+
+These dependencies are bundled in the repository. Run `git submodule update --init` if you haven't already.
+
+### Alpine Linux (not tested)
+
+```sh
+su
+apk add clang libzip-dev fts-dev
+make -j8
+```
+
+### Debian
+
+```sh
+sudo apt install clang make automake libtool
+make -j8
+```
+
+### RHEL/CentOS (not tested)
+
+```sh
+sudo yum install clang
+make -j8
+```
+
+### Windows
+
+I'm too lazy to find out the steps of the 99-step build process. Just use [WSL](https://docs.microsoft.com/en-us/windows/wsl/install-win10).

+ 3 - 34
docs/index.md

@@ -1,35 +1,4 @@
-## Building
+# Documentation index
 
-soulmate requires the following dependencies :
-
-- [libuv](https://libuv.org/)
-
-- [BearSSL](https://bearssl.org/)
-
-These dependencies are bundled in the repository. Run `git submodule update --init` if you haven't already.
-
-### Alpine Linux (not tested)
-
-```sh
-su
-apk add clang libzip-dev fts-dev
-make -j8
-```
-
-### Debian
-
-```sh
-sudo apt install clang make automake libtool
-make -j8
-```
-
-### RHEL/CentOS (not tested)
-
-```sh
-sudo yum install clang
-make -j8
-```
-
-### Windows
-
-I'm too lazy to find out the steps of the 99-step build process. Just use [WSL](https://docs.microsoft.com/en-us/windows/wsl/install-win10).
+- [Building soulmate](building.md)
+- [HKMP Protocol description](protocol.md)

+ 10 - 0
docs/protocol.md

@@ -0,0 +1,10 @@
+HKMP datagrams have the following format:
+
+| length      | ushort          |
+| sequence    | ushort          |
+| ack         | ushort          |
+| ack_field   | uint (bitfield) |
+| packet_type | ushort          |
+| packet_data | bytes           |
+
+For the different packet types available, see `ClientPacketType` and `ServerPacketType` in `protocol.h`. To see what format they are in and/or what they do, just read the code lol (sorry).

+ 0 - 56
src/customknight.c

@@ -1,56 +0,0 @@
-#include "customknight.h"
-
-#include <bearssl_hash.h>
-#include <stdlib.h>
-
-#include "player.h"
-#include "protocol.h"
-
-PacketReadResult handle_texture_receive(Player* player, char* data, int length,
-                                        int pos) {
-  (void)player;
-
-  int texture_length;
-  READ_INT(texture_length);
-  if (texture_length > 20000000) {
-    // Over 20mb really ? That's going to be a 'no from me'.
-    return PLAYER_DESERVES_KICK;
-  }
-
-  uv_fs_t open_req = {0};
-  open_req.data = malloc(texture_length);
-  READ_BYTES(open_req.data, texture_length);
-
-  /*  br_sha1_context ctx = {0};
-    br_sha1_init(&ctx);
-    br_sha1_update(&ctx, open_req->data, texture_length);
-
-    unsigned char sha1[HASH_LENGTH];
-    br_sha1_out(&ctx, sha1);
-
-    char sha1_str[HASH_LENGTH * 2 + 7] = "skins/";
-    for (int i = 0; i < HASH_LENGTH; i++) {
-      sprintf(sha1_str + 6 + i * 2, "%02X", buf[i])
-    }
-    sha1_str[HASH_LENGTH * 2 + 6] = '\0';
-
-      int fd = uv_fs_open(uv_default_loop(), &open_req, sha1_str, O_CREAT,
-       O_WRONLY, save_texture);*/
-
-  /*  FILE* outfile = fopen(sha1_str, "w");
-    fwrite(open_req->data, 1, texture_length, outfile);
-    fclose(outfile);*/
-
-  return DONE_READING;
-}
-
-PacketReadResult handle_texture_request(Player* player, char* data, int length,
-                                        int pos) {
-  unsigned char sha1[HASH_LENGTH];
-  READ_BYTES(sha1, HASH_LENGTH);
-
-  // TODO: send texture
-  (void)player;
-
-  return DONE_READING;
-}

+ 0 - 28
src/customknight.h

@@ -1,28 +0,0 @@
-#pragma once
-
-// Forward declarations
-typedef enum read_packet_retval PacketReadResult;
-typedef struct player_s Player;
-
-#define HASH_LENGTH 20
-
-typedef enum texture_type_e {
-  BALDUR_TEXTURE,
-  FLUKE_TEXTURE,
-  GRIMM_TEXTURE,
-  HATCHLING_TEXTURE,
-  KNIGHT_TEXTURE,
-  SHIELD_TEXTURE,
-  SPRINT_TEXTURE,
-  UNN_TEXTURE,
-  VOID_TEXTURE,
-  VS_TEXTURE,
-  WEAVER_TEXTURE,
-  WRAITHS_TEXTURE,
-  NB_TEXTURES
-} TextureType;
-
-PacketReadResult handle_texture_receive(Player* player, char* data, int length,
-                                        int pos);
-PacketReadResult handle_texture_request(Player* player, char* data, int length,
-                                        int pos);

+ 16 - 21
src/http.c

@@ -2,6 +2,7 @@
 #include <time.h>
 #include <uv.h>
 
+#include "player.h"
 #include "server.h"
 
 uv_tcp_t* http_server = NULL;
@@ -13,9 +14,7 @@ uv_tcp_t* http_server = NULL;
   "Content-Length: %d\r\n\r\n"
 
 void free_tcp_connection(uv_handle_t* handle) {
-  if (handle->data) {
-    free(handle->data);
-  }
+  free(handle->data);
   free(handle);
 }
 
@@ -47,17 +46,15 @@ void new_http_connection(uv_stream_t* server, int status) {
 
   // Calculate HTTP response length
   int body_length = snprintf(NULL, 0,
-                             "Server uptime : %02d:%02d:%02d\r\n\r\n"
-                             "Players online (%d) :\r\n",
-                             hours, minutes, seconds, nb_players);
-  for (int i = 0; i < nb_players; i++) {
+                             "Server uptime: %02d:%02d:%02d\r\n\r\n"
+                             "Players online:\r\n",
+                             hours, minutes, seconds);
+  for (int i = 0; i < MAX_PLAYERS; i++) {
+    if (players[i].username[0] == '\0') continue;
     body_length += snprintf(NULL, 0,
                             "\r\n* %s\r\n"
-                            "Scene: %s\r\n"
-                            "Health: %d/%d\r\n",
-                            players[i].username, players[i].scene,
-                            players[i].health + players[i].blue_health,
-                            players[i].max_health);
+                            "Scene: %s\r\n",
+                            players[i].username, players[i].scene);
   }
   int header_length = snprintf(NULL, 0, HTTP_HEADER, body_length);
 
@@ -65,17 +62,15 @@ void new_http_connection(uv_stream_t* server, int status) {
   tcp_connection->data = malloc(header_length + body_length + 1);
   int pos = sprintf(tcp_connection->data, HTTP_HEADER, body_length);
   pos += sprintf(tcp_connection->data + pos,
-                 "Server uptime : %02d:%02d:%02d\r\n\r\n"
-                 "Players online (%d) :\r\n",
-                 hours, minutes, seconds, nb_players);
-  for (int i = 0; i < nb_players; i++) {
+                 "Server uptime: %02d:%02d:%02d\r\n\r\n"
+                 "Players online:\r\n",
+                 hours, minutes, seconds);
+  for (int i = 0; i < MAX_PLAYERS; i++) {
+    if (players[i].username[0] == '\0') continue;
     pos += sprintf(tcp_connection->data + pos,
                    "\r\n* %s\r\n"
-                   "Scene: %s\r\n"
-                   "Health: %d/%d\r\n",
-                   players[i].username, players[i].scene,
-                   players[i].health + players[i].blue_health,
-                   players[i].max_health);
+                   "Scene: %s\r\n",
+                   players[i].username, players[i].scene);
   }
 
   uv_write_t* res = malloc(sizeof(uv_write_t));

+ 22 - 24
src/main.c

@@ -4,13 +4,22 @@
 #include <uv.h>
 
 #include "http.h"
+#include "player.h"
 #include "server.h"
-#include "tcp.h"
 #include "udp.h"
 
 const int BACKLOG = 128;
 const int PORT = 26950;
 
+// TODO: on sigterm, cleanly shut down by sending shutdown packets to everyone
+// (double check if this is useful first)
+
+void basic_alloc(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
+  (void)handle;
+  buf->base = malloc(suggested_size);
+  buf->len = suggested_size;
+}
+
 int main(void) {
 #ifndef _WIN32
   // Pls no crasherino
@@ -19,8 +28,7 @@ int main(void) {
 
   uv_loop_t* loop = uv_default_loop();
   http_server = malloc(sizeof(uv_tcp_t));
-  hollowknight_tcp_server = malloc(sizeof(uv_tcp_t));
-  hollowknight_udp_server = malloc(sizeof(uv_udp_t));
+  hollowknight_server = malloc(sizeof(uv_udp_t));
   start_tms = time(NULL);
 
   // HTTP Listen
@@ -35,32 +43,18 @@ int main(void) {
       fprintf(stderr, "Failed to listen: %s\n", uv_strerror(err));
       return 1;
     }
-    printf("Listening on 0.0.0.0:%d...\n", HTTP_PORT);
-  }
-
-  // TCP Listen
-  {
-    struct sockaddr_in addr;
-    uv_tcp_init(loop, hollowknight_tcp_server);
-    uv_ip4_addr("0.0.0.0", PORT, &addr);
-    uv_tcp_bind(hollowknight_tcp_server, (const struct sockaddr*)&addr, 0);
-    int err = uv_listen((uv_stream_t*)hollowknight_tcp_server, BACKLOG,
-                        new_tcp_connection);
-    if (err) {
-      fprintf(stderr, "Failed to listen: %s\n", uv_strerror(err));
-      return 1;
-    }
-    printf("Listening on 0.0.0.0:%d...\n", PORT);
+    printf("[HTTP] Listening on 0.0.0.0:%d...\n", HTTP_PORT);
   }
 
   // UDP Listen
   {
     struct sockaddr_in addr;
-    uv_udp_init(loop, hollowknight_udp_server);
+    uv_udp_init_ex(loop, hollowknight_server, UV_UDP_RECVMMSG);
     uv_ip4_addr("0.0.0.0", PORT, &addr);
-    uv_udp_bind(hollowknight_udp_server, (const struct sockaddr*)&addr,
+    uv_udp_bind(hollowknight_server, (const struct sockaddr*)&addr,
                 UV_UDP_REUSEADDR);
-    uv_udp_recv_start(hollowknight_udp_server, udp_alloc, udp_read);
+    uv_udp_recv_start(hollowknight_server, basic_alloc, udp_read);
+    printf("[UDP] Listening on 0.0.0.0:%d...\n", PORT);
   }
 
   // Timer to kick inactive clients
@@ -69,9 +63,13 @@ int main(void) {
   uv_timer_start(&timer_req, kick_idle_players, 1000 * IDLE_PLAYER_TIMEOUT,
                  1000);
 
+  // Tick timer
+  uv_timer_t timer_tick;
+  uv_timer_init(loop, &timer_tick);
+  uv_timer_start(&timer_tick, process_tick, 0, 1000 / TICKRATE);
+
   int res = uv_run(loop, UV_RUN_DEFAULT);
   free(http_server);
-  free(hollowknight_tcp_server);
-  free(hollowknight_udp_server);
+  free(hollowknight_server);
   return res;
 }

+ 0 - 8
src/misc.h

@@ -1,8 +0,0 @@
-#pragma once
-#include <uv.h>
-
-typedef struct vector3_s {
-  float x;
-  float y;
-  float z;
-} Vector3;

+ 24 - 42
src/player.c

@@ -3,57 +3,39 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "customknight.h"
+#include "protocol.h"
 #include "server.h"
-#include "tcp.h"
+#include "udp.h"
 
-void make_player_info_packet(Player* player, char packet[MAX_PACKET_LENGTH],
-                             int* length) {
-  int pos = 4;
-  WRITE_INT(S_PACKET_SPAWN_PLAYER);
-  WRITE_BYTE(player->player_id);
-  WRITE_STRING(player->username);
-  WRITE_VEC3(player->position);
-  WRITE_VEC3(player->scale);
-  WRITE_STRING(player->animation);
-  for (int i = 0; i < NB_CHARMS; i++) {
-    WRITE_BOOL(player->charms[i]);
-  }
-
-  // TODO: send actual hashes
-  unsigned char fake_hash[HASH_LENGTH] = {0};
-  for (int i = 0; i < NB_TEXTURES; i++) {
-    WRITE_BYTES(fake_hash, HASH_LENGTH);
-  }
+Player players[MAX_PLAYERS];
 
-  *length = pos;
-}
+void free_player(Player* player) {
+  free(player->must_send_packets);
+  free(player->may_send_packets);
 
-void free_player(uv_handle_t* handle) {
-  Player* player = handle->data;
-  Player* last_player = &players[nb_players - 1];
-  if (player != last_player) {
-    memmove(player, last_player, sizeof(Player));
+  for (int i = 0; i < player->nb_unacked_packets; i++) {
+    uv_timer_stop(&player->unacked_packets[i].timer);
+    free(player->unacked_packets[i].buffer.base);
   }
 
-  nb_players--;
-  free(handle);
+  memset(player, 0, sizeof(Player));
 }
 
-void kick_player(Player* player) {
-  // First off, remove the player from all TCP/UDP broadcasts.
-  uv_handle_t* handle = (uv_handle_t*)player->tcp_connection;
-  if (handle == NULL) return;
-  player->tcp_connection = NULL;
+void kick_player(Player* player, bool is_timeout) {
+  if (is_timeout) {
+    printf("%s (%hd) left the server (timed out).\n", player->username,
+           player->id);
+  } else {
+    printf("%s (%hd) left the server.\n", player->username, player->id);
+  }
 
-  // Then broadcast the kick to the other players.
-  printf("%s (%hhd) left the server.\n", player->username, player->player_id);
   remove_player_from_scene(player);
-  INIT_PACKET(S_PACKET_PLAYER_DISCONNECTED);
-  WRITE_BYTE(player->player_id);
-  BROADCAST_PACKET_TCP(player);
 
-  // Close the TCP connection. Once it is closed, free_player() will properly
-  // delete the player and free the TCP connection handle.
-  uv_close(handle, free_player);
+  INIT_PACKET(S_PACKET_DISCONNECT);
+  WRITE_SHORT(player->id);
+  WRITE_STRING(player->username);
+  WRITE_BOOL(is_timeout);
+  IMPORTANT_SERVER_BROADCAST(player);
+
+  free_player(player);
 }

+ 41 - 18
src/player.h

@@ -1,33 +1,56 @@
 #pragma once
+#include <sys/time.h>
 #include <uv.h>
 
-#include "customknight.h"
-#include "misc.h"
 #include "protocol.h"
+#include "server.h"
+
+typedef struct unacked_packet_s {
+  // We can store the player pointer in a structure that gets passed to libuv,
+  // because we cancel the timer before freeing the player.
+  Player* player;
+
+  unsigned char resends;
+  unsigned short sequence;
+  uv_timer_t timer;
+  uv_buf_t buffer;
+
+  struct timespec send_time;
+} UnackedPacket;
 
 typedef struct player_s {
-  uv_tcp_t* tcp_connection;
+  // Networking
   struct sockaddr_storage addr;
-
   time_t last_packet_tms;
-  char current_packet[MAX_PACKET_LENGTH];
-  int current_packet_pos;
-  unsigned char player_id;
+  unsigned short local_sequence_number;
+  unsigned short ack;
+  unsigned int ack_field;
+  uv_buf_t* must_send_packets;
+  uv_buf_t* may_send_packets;
+  int nb_must_send_packets;
+  int nb_may_send_packets;
+  int outgoing_bytes;
+  int nb_unacked_packets;
+  UnackedPacket* unacked_packets;
+  unsigned short rtt;
 
+  // Settings
+  unsigned short id;
   char username[MAX_STRING_LENGTH];
-  char animation[MAX_STRING_LENGTH];
+  unsigned char team;
+  unsigned char skin_id;
+  bool is_scene_host;
+
+  // Info
   char scene[MAX_STRING_LENGTH];
-  Vector3 position;
-  Vector3 scale;
-  int health;
-  int max_health;
-  int blue_health;
-  bool charms[NB_CHARMS];
-  unsigned char texture_hashes[HASH_LENGTH * NB_TEXTURES];
+  unsigned short animation;
+  float x, y;
+  float map_x, map_y;
+  bool scale;
 } Player;
 
-void make_player_info_packet(Player* player, char packet[MAX_PACKET_LENGTH],
-                             int* length);
 void end_udp_write(uv_udp_send_t* req, int status);
 void end_write(uv_write_t* req, int status);
-void kick_player(Player* player);
+void kick_player(Player* player, bool is_timeout);
+
+extern Player players[MAX_PLAYERS];

+ 277 - 148
src/protocol.c

@@ -2,198 +2,327 @@
 
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
+#include <sys/time.h>
 
-#include "customknight.h"
 #include "player.h"
 #include "server.h"
-#include "tcp.h"
 #include "udp.h"
 
-PacketReadResult read_tcp_packet(Player* player) {
-  char* data = player->current_packet;
-  int length = player->current_packet_pos;
+// TODO: test this function
+int difference_ignoring_wraparound(int a, int b, int max_length) {
+  int diff = b - a;
+  if (diff > max_length / 2 || diff < -max_length / 2) {
+    a = (a + (max_length / 2)) % max_length;
+    b = (b + (max_length / 2)) % max_length;
+    return b - a;
+  } else {
+    return b - a;
+  }
+}
+
+int handle_packet(Player* player, char* data, int length) {
   int pos = 0;
 
-  int packet_length;
-  READ_INT(packet_length);
-  if (packet_length > length) {
-    return NEEDS_MORE_BYTES;
+  unsigned short packet_length;
+  READ_SHORT(packet_length);
+  if (packet_length > length) return packet_length;
+
+  unsigned short sequence;
+  READ_SHORT(sequence);
+  int diff = difference_ignoring_wraparound(player->ack, sequence, USHRT_MAX);
+  if (diff >= 0) {
+    player->ack_field <<= diff;
+    player->ack_field |= 1;
+    player->ack = sequence;
+  } else if (-diff < 32) {
+    player->ack_field |= (1 << -diff);
   }
 
-  ClientPacketType type;
-  READ_INT(type);
-
-  switch (type) {
-    //
-    // -> When the player joins the server
-    case C_PACKET_WELCOME_ACK: {
-      unsigned char player_id;
-      READ_BYTE(player_id);
-      if (player_id != player->player_id) {
-        return PLAYER_DESERVES_KICK;
+  // Ack unacked packets that match the given ack field
+  unsigned short ack;
+  READ_SHORT(ack);
+  unsigned int ack_field;
+  READ_INT(ack_field);
+  for (int i = 0; i < 32; i++) {
+    if ((ack_field >> i) & 1) {
+      int acked_sequence = (ack - i) % USHRT_MAX;
+      for (int j = 0; j < player->nb_unacked_packets; j++) {
+        if (player->unacked_packets[j].sequence == acked_sequence) {
+          uv_timer_stop(&player->unacked_packets[j].timer);
+          free(player->unacked_packets[j].buffer.base);
+
+          struct timespec send_time = player->unacked_packets[j].send_time;
+          struct timespec recv_time;
+          clock_gettime(CLOCK_MONOTONIC_COARSE, &recv_time);
+          uint64_t rtt = (recv_time.tv_sec - send_time.tv_sec) * 1000000 +
+                         (recv_time.tv_nsec - send_time.tv_nsec) / 1000;
+          player->rtt += (rtt - player->rtt) / 10;
+
+          if (j + 1 < player->nb_unacked_packets) {
+            memmove(&player->unacked_packets[j],
+                    &player->unacked_packets[j + 1], sizeof(UnackedPacket));
+          }
+          player->nb_unacked_packets--;
+          break;
+        }
       }
+    }
+  }
+
+  unsigned short packet_type;
+  READ_SHORT(packet_type);
+
+  if (player->username[0] == '\0' && packet_type != C_PACKET_LOGIN) {
+    // Ignore packet
+    return packet_length + sizeof(unsigned short);
+  }
 
+  // TODO: reading directly into the player struct might cause some unwanted
+  // behavior if the packets aren't complete. read into temporary variables
+  // if needed.
+
+  switch (packet_type) {
+    case C_PACKET_LOGIN: {
       READ_STRING(player->username);
-      READ_STRING(player->animation);
-      READ_STRING(player->scene);
-      READ_VEC3(player->position);
-      READ_VEC3(player->scale);
-      READ_INT(player->health);
-      READ_INT(player->max_health);
-      READ_INT(player->blue_health);
-      for (int i = 0; i < NB_CHARMS; i++) {
-        READ_BOOL(player->charms[i]);
+
+      // Pick unused player id
+      static unsigned short new_player_id = 0;
+      new_player_id = new_player_id + 1 % 32767;
+      int new_id_found = 0;
+      while (!new_id_found) {
+        new_id_found = 1;
+        for (int i = 0; i < MAX_PLAYERS; i++) {
+          if (players[i].id == new_player_id) {
+            // '32767' is max unsigned short value
+            new_player_id = new_player_id + 1 % 32767;
+            new_id_found = 0;
+            break;
+          }
+        }
       }
 
-      // Send player to existing players
-      char packet[MAX_PACKET_LENGTH];
-      int player_info_packet_length;
-      make_player_info_packet(player, packet, &player_info_packet_length);
-      BROADCAST_PACKET_TCP(player);
+      player->id = new_player_id;
 
-      // Let the player know what's in their current scene
-      send_scene_info_to(player);
+      INIT_PACKET(S_PACKET_LOGIN);
+      WRITE_BYTE(0);
+      IMPORTANT_PACKET_SEND(player);
 
-      printf("%s (%hhd) joined the server.\n", player->username,
-             player->player_id);
-      return DONE_READING;
+      return pos;
     }
 
-    //
-    // -> When the player sends a texture
-    case C_PACKET_TEXTURE_FRAGMENT: {
-      return handle_texture_receive(player, data, length, pos);
-    }
+    case C_PACKET_HELLO: {
+      READ_STRING(player->username);
+      READ_STRING(player->scene);
+      READ_FLOAT(player->x);
+      READ_FLOAT(player->y);
+      READ_BOOL(player->scale);
+      READ_SHORT(player->animation);
 
-    //
-    // -> When the player requests a texture
-    case S_PACKET_TEXTURE_REQUEST: {
-      return handle_texture_request(player, data, length, pos);
-    }
+      INIT_PACKET(S_PACKET_UPDATE_SETTINGS);
+      WRITE_BOOL(PVP_ENABLED);
+      WRITE_BOOL(BODY_DAMAGE_ENABLED);
+      WRITE_BOOL(ALWAYS_SHOW_MAP_ICONS);
+      WRITE_BOOL(ONLY_SHOW_MAP_ICONS_WITH_WAYWARD_COMPASS);
+      WRITE_BOOL(DISPLAY_NAMES);
+      WRITE_BOOL(TEAMS_ENABLED);
+      WRITE_BOOL(ALLOW_SKINS);
+      WRITE_BYTE(NAIL_DAMAGE);
+      WRITE_BYTE(GRUBBERFLY_ELEGY_DAMAGE);
+      WRITE_BYTE(VENGEFUL_SPIRIT_DAMAGE);
+      WRITE_BYTE(SHADE_SOUL_DAMAGE);
+      WRITE_BYTE(DESOLATE_DIVE_DAMAGE);
+      WRITE_BYTE(HOWLING_WRAITH_DAMAGE);
+      WRITE_BYTE(ABYSS_SHRIEK_DAMAGE);
+      WRITE_BYTE(GREAT_SLASH_DAMAGE);
+      WRITE_BYTE(DASH_SLASH_DAMAGE);
+      WRITE_BYTE(CYCLONE_SLASH_DAMAGE);
+      WRITE_BYTE(SPORE_SHROOM_DAMAGE);
+      WRITE_BYTE(SPORE_DUNG_SHROOM_DAMAGE);
+      WRITE_BYTE(THORN_OF_AGONY_DAMAGE);
+      IMPORTANT_PACKET_SEND(player);
 
-    //
-    // -> When the player enters a new scene
-    case C_PACKET_SCENE_CHANGED: {
-      char new_scene[MAX_STRING_LENGTH];
-      READ_STRING(new_scene);
-      if (strcmp(new_scene, player->scene) == 0) return PLAYER_DESERVES_KICK;
+      {
+        INIT_PACKET(S_PACKET_CONNECT);
+        WRITE_SHORT(player->id);
+        WRITE_STRING(player->username);
+        IMPORTANT_SERVER_BROADCAST(player);
+      }
 
-      remove_player_from_scene(player);
-      strcpy(player->scene, new_scene);
-      send_scene_info_to(player);
+      add_player_to_scene(player);
 
-      return DONE_READING;
+      return pos;
     }
 
-    //
-    // -> When the player's health changes
-    case C_PACKET_HEALTH_UPDATED: {
-      READ_INT(player->health);
-      READ_INT(player->max_health);
-      READ_INT(player->blue_health);
-      INIT_PACKET(S_PACKET_HEALTH_UPDATED);
-      WRITE_BYTE(player->player_id);
-      WRITE_INT(player->health);
-      WRITE_INT(player->max_health);
-      WRITE_INT(player->blue_health);
-      BROADCAST_PACKET_TCP(player);
-      return DONE_READING;
+    case C_PACKET_DISCONNECT: {
+      kick_player(player, 0);
+      return pos;
     }
 
-    //
-    // -> When the player changes their charms
-    case C_PACKET_CHARMS_UPDATE: {
-      for (int i = 0; i < NB_CHARMS; i++) {
-        READ_BOOL(player->charms[i]);
+    case C_PACKET_UPDATE_PLAYER: {
+      unsigned char nb_animations = 0;
+
+      // This will get a bit confusing, but we're writing the packet we're
+      // going to broadcast while still reading the received packet.
+      INIT_PACKET(S_PACKET_UPDATE_PLAYER);
+
+      unsigned short unused_player_id;
+      READ_SHORT(unused_player_id);
+      WRITE_SHORT(player->id);
+
+      unsigned char update_flag;
+      READ_BYTE(update_flag);
+      WRITE_BYTE(update_flag);
+
+      if (update_flag & (1 << PLAYER_UPDATE_POSITION)) {
+        READ_FLOAT(player->x);
+        READ_FLOAT(player->y);
+        WRITE_FLOAT(player->x);
+        WRITE_FLOAT(player->y);
+      }
+
+      if (update_flag & (1 << PLAYER_UPDATE_SCALE)) {
+        READ_BOOL(player->scale);
+        WRITE_BOOL(player->scale);
       }
-      INIT_PACKET(S_PACKET_CHARMS_UPDATE);
-      WRITE_BYTE(player->player_id);
-      for (int i = 0; i < NB_CHARMS; i++) {
-        WRITE_BOOL(player->charms[i]);
+
+      if (update_flag & (1 << PLAYER_UPDATE_MAP_POSITION)) {
+        READ_FLOAT(player->map_x);
+        READ_FLOAT(player->map_y);
+        WRITE_FLOAT(player->map_x);
+        WRITE_FLOAT(player->map_y);
+
+        // TODO: if(ALWAYS_SHOW_ICONS || ONLY_SHOW_MAP_ICONS_W/_WWD_COMPASS)
+        //       broadcast map position update to whole server insteaf of
+        //       current scene
       }
-      BROADCAST_PACKET_TCP(player);
-      return DONE_READING;
+
+      if (update_flag & (1 << PLAYER_UPDATE_ANIMATION)) {
+        READ_BYTE(nb_animations);
+        WRITE_BYTE(nb_animations);
+
+        for (int i = 0; i < nb_animations; i++) {
+          READ_SHORT(player->animation);
+          WRITE_SHORT(player->animation);
+
+          unsigned char frame;
+          READ_BYTE(frame);
+          WRITE_BYTE(frame);
+
+          unsigned char num_effects;
+          READ_BYTE(num_effects);
+          WRITE_BYTE(num_effects);
+
+          // There is one effect per bit. So read (num_effects / 8) bytes.
+          for (int j = 0; j < num_effects; j += 8) {
+            unsigned char tmp;
+            READ_BYTE(tmp);
+            WRITE_BYTE(tmp);
+          }
+        }
+      }
+
+      SCENE_BROADCAST(player);
     }
 
-    //
-    // -> When the player leaves the server gracefully
-    case C_PACKET_PLAYER_DISCONNECTED:
-      return PLAYER_DESERVES_KICK;
+    case C_PACKET_UPDATE_ENTITY: {
+      // TODO: confirm sender is scene host before relaying
 
-    //
-    // -> When the player comes from the future
-    default:
-      printf("Unhandled TCP packet type %d\n", type);
-      return DONE_READING;
-  }
-}
+      // This will get a bit confusing, but we're writing the packet we're
+      // going to broadcast while still reading the received packet.
+      INIT_PACKET(S_PACKET_UPDATE_ENTITY);
 
-PacketReadResult read_udp_packet(char* data, int length) {
-  int pos = 0;
+      unsigned char entity_type;
+      READ_BYTE(entity_type);
+      WRITE_BYTE(entity_type);
 
-  unsigned char player_id;
-  READ_BYTE(player_id);
+      unsigned char entity_id;
+      READ_BYTE(entity_id);
+      WRITE_BYTE(entity_id);
 
-  int packet_length;
-  READ_INT(packet_length);
-  if (packet_length > length) return NEEDS_MORE_BYTES;
+      unsigned char update_flag;
+      READ_BYTE(update_flag);
+      WRITE_BYTE(update_flag);
 
-  ClientPacketType type;
-  READ_INT(type);
+      if (update_flag & (1 << ENTITY_UPDATE_POSITION)) {
+        float x, y;
+        READ_FLOAT(x);
+        READ_FLOAT(y);
+        WRITE_FLOAT(x);
+        WRITE_FLOAT(y);
+      }
+
+      if (update_flag & (1 << ENTITY_UPDATE_STATE)) {
+        unsigned char state;
+        READ_BYTE(state);
+        WRITE_BYTE(state);
+      }
+
+      if (update_flag & (1 << ENTITY_UPDATE_VARIABLES)) {
+        unsigned char num_bytes;
+        READ_BYTE(num_bytes);
+        WRITE_BYTE(num_bytes);
 
-  Player* player = NULL;
-  for (int i = 0; i < nb_players; i++) {
-    if (players[i].player_id == player_id) {
-      player = &players[i];
-      break;
+        for (int i = 0; i < num_bytes; i++) {
+          unsigned char tmp;
+          READ_BYTE(tmp);
+          WRITE_BYTE(tmp);
+        }
+      }
+
+      SCENE_BROADCAST(player);
     }
-  }
-  if (player == NULL) {
-    printf("UDP: Player ID %hhd not in use\n", player_id);
-    return PLAYER_DESERVES_KICK;
-  } else {
-    player->last_packet_tms = time(NULL);
-  }
 
-  switch (type) {
-    //
-    // -> When the player moves
-    case C_PACKET_PLAYER_POSITION: {
-      READ_VEC3(player->position);
-      INIT_PACKET(S_PACKET_PLAYER_POSITION);
-      WRITE_BYTE(player->player_id);
-      WRITE_VEC3(player->position);
-      BROADCAST_PACKET_UDP(player);
-      return DONE_READING;
+    case C_PACKET_ENTER_SCENE: {
+      READ_STRING(player->scene);
+      READ_FLOAT(player->x);
+      READ_FLOAT(player->y);
+      READ_BOOL(player->scale);
+      READ_SHORT(player->animation);
+
+      add_player_to_scene(player);
+
+      return pos;
     }
 
-    //
-    // -> When the player's scale updates (when ???)
-    case C_PACKET_PLAYER_SCALE: {
-      READ_VEC3(player->scale);
-      INIT_PACKET(S_PACKET_PLAYER_SCALE);
-      WRITE_BYTE(player->player_id);
-      WRITE_VEC3(player->scale);
-      BROADCAST_PACKET_UDP(player);
-      return DONE_READING;
+    case C_PACKET_LEAVE_SCENE: {
+      remove_player_from_scene(player);
+
+      return pos;
     }
 
-    //
-    // -> When the player's animation updates
-    case C_PACKET_PLAYER_ANIMATION: {
-      READ_STRING(player->animation);
-      INIT_PACKET(S_PACKET_PLAYER_ANIMATION);
-      WRITE_BYTE(player->player_id);
-      WRITE_STRING(player->animation);
-      BROADCAST_PACKET_UDP(player);
-      return DONE_READING;
+    case C_PACKET_DIE: {
+      INIT_PACKET(S_PACKET_DIE);
+      WRITE_SHORT(player->id);
+      SCENE_BROADCAST(player);
+
+      return pos;
+    }
+
+    case C_PACKET_UPDATE_TEAM: {
+      READ_BYTE(player->team);
+
+      INIT_PACKET(S_PACKET_UPDATE_TEAM);
+      WRITE_SHORT(player->id);
+      WRITE_STRING(player->username);
+      WRITE_BYTE(player->team);
+      IMPORTANT_SERVER_BROADCAST(player);
+
+      return pos;
+    }
+
+    case C_PACKET_UPDATE_SKIN: {
+      READ_BYTE(player->skin_id);
+
+      INIT_PACKET(S_PACKET_UPDATE_SKIN);
+      WRITE_SHORT(player->id);
+      WRITE_BYTE(player->skin_id);
+      IMPORTANT_SCENE_BROADCAST(player);
+
+      return pos;
     }
 
-    //
-    // -> When the player comes from the future
     default:
-      printf("Unhandled UDP packet type %d\n", type);
-      return PLAYER_DESERVES_KICK;
+      printf("Unhandled UDP packet type %d\n", packet_type);
+      return packet_length + sizeof(unsigned short);
   }
 }

+ 80 - 62
src/protocol.h

@@ -1,59 +1,68 @@
 #pragma once
+#include <limits.h>
 #include <stdbool.h>
 #include <uv.h>
 
-#include "misc.h"
-
-// Static packet length to simplify allocation
-#define MAX_PACKET_LENGTH 4096
-
 // Maximum string length, including the null terminator.
-#define MAX_STRING_LENGTH 256
-
-#define NB_CHARMS 40
+// HKMP allows strings up to USHRT_MAX, but let's not.
+#define MAX_STRING_LENGTH 200
 
 // Sent from server to client
 typedef enum server_packet_e {
-  S_PACKET_WELCOME = 1,
-  S_PACKET_SPAWN_PLAYER,
-  S_PACKET_TEXTURE_FRAGMENT,
-  S_PACKET_TEXTURE_REQUEST,
-  S_PACKET_DESTROY_PLAYER,
-  S_PACKET_PVP_ENABLED,
-  S_PACKET_PLAYER_POSITION,
-  S_PACKET_PLAYER_SCALE,
-  S_PACKET_PLAYER_ANIMATION,
-  S_PACKET_HEALTH_UPDATED,
-  S_PACKET_CHARMS_UPDATE,
-  S_PACKET_PLAYER_DISCONNECTED
+  S_PACKET_LOGIN = 0,
+  S_PACKET_CONNECT,
+  S_PACKET_DISCONNECT,
+  S_PACKET_SERVER_SHUTDOWN,
+  S_PACKET_ENTER_SCENE,
+  S_PACKET_IN_SCENE,
+  S_PACKET_LEAVE_SCENE,
+  S_PACKET_UPDATE_PLAYER,
+  S_PACKET_UPDATE_ENTITY,
+  S_PACKET_DIE,
+  S_PACKET_UPDATE_TEAM,
+  S_PACKET_UPDATE_SKIN,
+  S_PACKET_UPDATE_SETTINGS,
 } ServerPacketType;
 
 // Sent from client to server
 typedef enum client_packet_e {
-  C_PACKET_WELCOME_ACK = 1,
-  C_PACKET_TEXTURE_FRAGMENT,
-  C_PACKET_TEXTURE_REQUEST,
-  C_PACKET_PLAYER_POSITION,
-  C_PACKET_PLAYER_SCALE,
-  C_PACKET_PLAYER_ANIMATION,
-  C_PACKET_SCENE_CHANGED,
-  C_PACKET_HEALTH_UPDATED,
-  C_PACKET_CHARMS_UPDATE,
-  C_PACKET_PLAYER_DISCONNECTED
+  C_PACKET_LOGIN = 0,
+  C_PACKET_HELLO,
+  C_PACKET_DISCONNECT,
+  C_PACKET_UPDATE_PLAYER,
+  C_PACKET_UPDATE_ENTITY,
+  C_PACKET_ENTER_SCENE,
+  C_PACKET_LEAVE_SCENE,
+  C_PACKET_DIE,
+  C_PACKET_UPDATE_TEAM,
+  C_PACKET_UPDATE_SKIN,
 } ClientPacketType;
 
+typedef enum {
+  ENTITY_UPDATE_POSITION = 0,
+  ENTITY_UPDATE_STATE,
+  ENTITY_UPDATE_VARIABLES,
+} EntityUpdateType;
+
+typedef enum {
+  PLAYER_UPDATE_POSITION = 0,
+  PLAYER_UPDATE_SCALE,
+  PLAYER_UPDATE_MAP_POSITION,
+  PLAYER_UPDATE_ANIMATION
+} PlayerUpdateType;
+
 // Reads n bytes and copies them to out_ptr.
 // out_ptr needs to be already allocated.
-#define READ_BYTES(out_ptr, n)             \
-  if (length < n) return NEEDS_MORE_BYTES; \
-  memcpy(out_ptr, data + pos, n);          \
-  length -= n;                             \
+#define READ_BYTES(out_ptr, n)    \
+  if (length < n) return pos + n; \
+  memcpy(out_ptr, data + pos, n); \
+  length -= n;                    \
   pos += n
 
 #define READ_BYTE(var) READ_BYTES(&var, 1)
+#define READ_SHORT(var) READ_BYTES(&var, 2)
 #define READ_INT(var) READ_BYTES(&var, 4)
 #define READ_FLOAT(var) READ_BYTES(&var, 4)
-#define READ_VEC3(var) READ_BYTES(&var, 12)
 
 #define READ_BOOL(var)  \
   do {                  \
@@ -63,19 +72,20 @@ typedef enum client_packet_e {
   } while (0)
 
 // Reads a string to out_ptr.
+// out_ptr needs to be already allocated.
 // The macro ensures it doesn't exceed MAX_STRING_LENGTH - 1 bytes.
-#define READ_STRING(out_ptr)                                                \
-  do {                                                                      \
-    int string_length;                                                      \
-    READ_INT(string_length);                                                \
-    if (string_length > MAX_STRING_LENGTH - 1) return PLAYER_DESERVES_KICK; \
-    READ_BYTES(out_ptr, string_length);                                     \
-    out_ptr[string_length] = '\0';                                          \
+#define READ_STRING(out_ptr)                                               \
+  do {                                                                     \
+    unsigned short string_length;                                          \
+    READ_SHORT(string_length);                                             \
+    if (string_length > MAX_STRING_LENGTH - 1) return pos + string_length; \
+    READ_BYTES(out_ptr, string_length);                                    \
+    out_ptr[string_length] = '\0';                                         \
   } while (0)
 
-#define WRITE_BYTES(bytes, n)     \
-  memcpy(packet + pos, bytes, n); \
-  pos += n
+#define WRITE_BYTES(bytes, n)         \
+  memcpy(packet + out_pos, bytes, n); \
+  out_pos += n
 
 #define WRITE_BYTE(byte)         \
   do {                           \
@@ -89,32 +99,40 @@ typedef enum client_packet_e {
     WRITE_BYTES(&lvalue, 1); \
   } while (0)
 
+#define WRITE_FLOAT(num)     \
+  do {                       \
+    float lvalue = num;      \
+    WRITE_BYTES(&lvalue, 2); \
+  } while (0)
+
+#define WRITE_SHORT(num)         \
+  do {                           \
+    unsigned short lvalue = num; \
+    WRITE_BYTES(&lvalue, 2);     \
+  } while (0)
+
 #define WRITE_INT(num)       \
   do {                       \
     int lvalue = num;        \
     WRITE_BYTES(&lvalue, 4); \
   } while (0)
 
-#define WRITE_STRING(str)        \
-  do {                           \
-    int write_len = strlen(str); \
-    WRITE_INT(write_len);        \
-    WRITE_BYTES(str, write_len); \
+#define WRITE_STRING(str)                   \
+  do {                                      \
+    unsigned short write_len = strlen(str); \
+    WRITE_SHORT(write_len);                 \
+    WRITE_BYTES(str, write_len);            \
   } while (0)
 
-#define WRITE_VEC3(vec) WRITE_BYTES(&vec, 12)
+// static inline void deferred_free(void *p) {
+//         free(*(void**) p);
+// }
+// #define _free_on_scope_exit_ __attribute__((cleanup(deferred_free)))
 
-#define INIT_PACKET(packet_type)  \
-  int pos = 4;                    \
-  char packet[MAX_PACKET_LENGTH]; \
+#define INIT_PACKET(packet_type)                                   \
+  int out_pos = 0;                                                 \
+  __attribute__((cleanup(free))) char* packet = malloc(USHRT_MAX); \
   WRITE_INT(packet_type)
 
 typedef struct player_s Player;
-
-typedef enum read_packet_retval {
-  DONE_READING,
-  NEEDS_MORE_BYTES,
-  PLAYER_DESERVES_KICK
-} PacketReadResult;
-PacketReadResult read_tcp_packet(Player* player);
-PacketReadResult read_udp_packet(char* data, int length);
+int handle_packet(Player* player, char* data, int length);

+ 68 - 16
src/server.c

@@ -4,29 +4,80 @@
 #include <string.h>
 #include <time.h>
 
+#include "player.h"
 #include "protocol.h"
-#include "tcp.h"
+#include "udp.h"
 
-Player players[MAX_PLAYERS];
-int nb_players = 0;
 int start_tms = 0;
 
-void send_scene_info_to(Player* player) {
-  for (int i = 0; i < nb_players; i++) {
-    if (players[i].player_id == player->player_id) continue;
-    if (strcmp(players[i].scene, player->scene) != 0) continue;
+// This method assumes you already set player->scene to the new scene.
+void add_player_to_scene(Player* player) {
+  int players_in_scene = 0;
 
-    char packet[MAX_PACKET_LENGTH];
-    int pos;
-    make_player_info_packet(&players[i], packet, &pos);
-    SEND_PACKET(player);
+  // Send ENTER_SCENE to all players in the scene
+  {
+    INIT_PACKET(S_PACKET_ENTER_SCENE);
+    WRITE_SHORT(player->id);
+    WRITE_STRING(player->username);
+    WRITE_FLOAT(player->x);
+    WRITE_FLOAT(player->y);
+    WRITE_BOOL(player->scale);
+    WRITE_BYTE(player->team);
+    WRITE_BYTE(player->skin_id);
+    WRITE_SHORT(player->animation);
+
+    for (int i = 0; i < MAX_PLAYERS; i++) {
+      if (players[i].id != player->id &&
+          (strcmp(players[i].scene, player->scene) == 0)) {
+        players_in_scene++;
+        IMPORTANT_PACKET_SEND(&players[i]);
+      }
+    }
+  }
+
+  // Send scene info to player that just joined
+  {
+    INIT_PACKET(S_PACKET_IN_SCENE);
+
+    if (players_in_scene > 255) players_in_scene = 255;
+    WRITE_BYTE(players_in_scene);
+
+    for (int i = 0; i < MAX_PLAYERS; i++) {
+      if (players[i].id != player->id &&
+          (strcmp(players[i].scene, player->scene) == 0)) {
+        WRITE_SHORT(players[i].id);
+        WRITE_STRING(players[i].username);
+        WRITE_FLOAT(players[i].x);
+        WRITE_FLOAT(players[i].y);
+        WRITE_BOOL(players[i].scale);
+        WRITE_BYTE(players[i].team);
+        WRITE_BYTE(players[i].skin_id);
+        WRITE_SHORT(players[i].animation);
+      }
+    }
+
+    if (players_in_scene == 0) {
+      player->is_scene_host = true;
+    }
+    WRITE_BOOL(player->is_scene_host);
+
+    IMPORTANT_PACKET_SEND(player);
   }
 }
 
 void remove_player_from_scene(Player* player) {
-  INIT_PACKET(S_PACKET_DESTROY_PLAYER);
-  WRITE_BYTE(player->player_id);
-  BROADCAST_PACKET_TCP(player);
+  if (player->scene[0] == '\0') {
+    return;
+  }
+
+  INIT_PACKET(S_PACKET_LEAVE_SCENE);
+  WRITE_SHORT(player->id);
+  IMPORTANT_SCENE_BROADCAST(player);
+
+  player->scene[0] = '\0';
+  player->is_scene_host = false;
+
+  // TODO: add host rotation, i don't think that's done by HKMP?
 }
 
 // Kick players idle for more than IDLE_PLAYER_TIMEOUT seconds
@@ -34,9 +85,10 @@ void kick_idle_players(uv_timer_t* handle) {
   (void)handle;
 
   time_t current_tms = time(NULL);
-  for (int i = 0; i < nb_players; i++) {
+  for (int i = 0; i < MAX_PLAYERS; i++) {
+    if (players[i].username[0] == '\0') continue;
     if (players[i].last_packet_tms + IDLE_PLAYER_TIMEOUT < current_tms) {
-      kick_player(&players[i]);
+      kick_player(&players[i], 1);
     }
   }
 }

+ 43 - 12
src/server.h

@@ -1,20 +1,51 @@
 #pragma once
+#include <uv.h>
 
-#include "player.h"
-
-// Maximum is 255 due to player ID being an 8-bit value.
+// There can only be 255 players in a scene, so let's not allow more
 #define MAX_PLAYERS 255
 
-#define CUSTOM_KNIGHT 1
-#define PVP_ENABLED 0
+// How many updates per second should we send to each player?
+// NOTE: We define an 'update' as a group of packets totalling <= 508 bytes,
+// not as individual packets.
+#define TICKRATE 64
 
-// TODO: add a keepalive to the client to lower this
-#define IDLE_PLAYER_TIMEOUT 60
+// Maximum number of bytes to be sent per tick to each player. If a packet is
+// defined as 'important', it will be sent even if it goes over the limit.
+#define MAX_BYTES_PER_TICK 508
 
-extern Player players[MAX_PLAYERS];
-extern int nb_players;
-extern int start_tms;
+// Maximum number of unacked 'important' packets before the player gets kicked.
+#define MAX_UNACKED_PACKETS 100
+
+// Maximum number of times an 'important' packets is resent when unacked.
+#define MAX_RESENDS 10
+
+#define IDLE_PLAYER_TIMEOUT 5
 
-void send_scene_info_to(Player* player);
+// Game settings
+#define PVP_ENABLED 0
+#define BODY_DAMAGE_ENABLED 0
+#define ALWAYS_SHOW_MAP_ICONS 0
+#define ONLY_SHOW_MAP_ICONS_WITH_WAYWARD_COMPASS 1
+#define DISPLAY_NAMES 1
+#define TEAMS_ENABLED 0
+#define ALLOW_SKINS 1
+#define NAIL_DAMAGE 1
+#define GRUBBERFLY_ELEGY_DAMAGE 1
+#define VENGEFUL_SPIRIT_DAMAGE 1
+#define SHADE_SOUL_DAMAGE 2
+#define DESOLATE_DIVE_DAMAGE 1
+#define HOWLING_WRAITH_DAMAGE 1
+#define ABYSS_SHRIEK_DAMAGE 2
+#define GREAT_SLASH_DAMAGE 2
+#define DASH_SLASH_DAMAGE 2
+#define CYCLONE_SLASH_DAMAGE 1
+#define SPORE_SHROOM_DAMAGE 1
+#define SPORE_DUNG_SHROOM_DAMAGE 1
+#define THORN_OF_AGONY_DAMAGE 1
+
+typedef struct player_s Player;
+void add_player_to_scene(Player* player);
 void remove_player_from_scene(Player* player);
-void kick_idle_players(uv_timer_t* handle);
+void kick_idle_players(uv_timer_t* handle);
+
+extern int start_tms;

+ 0 - 141
src/tcp.c

@@ -1,141 +0,0 @@
-#include "tcp.h"
-
-#include <stdlib.h>
-#include <string.h>
-#include <time.h>
-#include <uv.h>
-
-#include "player.h"
-#include "server.h"
-
-uv_tcp_t* hollowknight_tcp_server = NULL;
-
-struct tcp_packet {
-  uv_write_t res;
-  char* packet;
-  Player* player;
-};
-
-void end_write(uv_write_t* req, int status) {
-  struct tcp_packet* packet = (struct tcp_packet*)req;
-  Player* player = packet->player;
-  free(packet->packet);
-  free(packet);
-
-  // Couldn't send the packet to the player. This usually means we lost
-  // connection. Kick them if they're not already.
-  if (status && player->tcp_connection != NULL) {
-    fprintf(stderr, "Write error: %s\n", uv_strerror(status));
-    kick_player(player);
-  }
-}
-
-void tcp_broadcast(char* data, int len, Player* source_player) {
-  // Insert packet length at the start of the payload.
-  *((int*)data) = len - 4;
-
-  for (int i = 0; i < nb_players; i++) {
-    uv_stream_t* stream = (uv_stream_t*)players[i].tcp_connection;
-    if (stream == NULL) continue;
-    if (players[i].player_id == source_player->player_id) continue;
-    if (strcmp(players[i].scene, source_player->scene) != 0) continue;
-
-    // Copy the packet for each write. TODO: SPEEDUP
-    struct tcp_packet* write = malloc(sizeof(struct tcp_packet));
-    write->packet = malloc(len);
-    write->player = &players[i];
-    memcpy(write->packet, data, len);
-
-    uv_buf_t wrbuf = uv_buf_init(write->packet, len);
-    uv_write((uv_write_t*)write, stream, &wrbuf, 1, end_write);
-  }
-}
-
-void tcp_send(char* data, int len, Player* player) {
-  if (player->tcp_connection == NULL) return;
-
-  // Insert packet length at the start of the payload.
-  *((int*)data) = len - 4;
-
-  // Copy the packet even though we shouldn't. TODO: SPEEDUP
-  struct tcp_packet* write = malloc(sizeof(struct tcp_packet));
-  write->packet = malloc(len);
-  write->player = player;
-  memcpy(write->packet, data, len);
-
-  uv_buf_t wrbuf = uv_buf_init(write->packet, len);
-  uv_write((uv_write_t*)write, (uv_stream_t*)player->tcp_connection, &wrbuf, 1,
-           end_write);
-}
-
-void tcp_alloc(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
-  (void)suggested_size;
-  Player* player = handle->data;
-  buf->base = &player->current_packet[player->current_packet_pos];
-  buf->len = MAX_PACKET_LENGTH - player->current_packet_pos;
-}
-
-void tcp_read(uv_stream_t* stream, ssize_t nread, const uv_buf_t* buf) {
-  (void)buf;
-  Player* player = stream->data;
-  player->last_packet_tms = time(NULL);
-
-  if (nread < 0) {
-    kick_player(player);
-  } else {
-    player->current_packet_pos += nread;
-    int res = read_tcp_packet(player);
-    switch (res) {
-      case DONE_READING:
-        player->current_packet_pos = 0;
-        break;
-      case NEEDS_MORE_BYTES:
-        break;
-      case PLAYER_DESERVES_KICK:
-        kick_player(player);
-        break;
-    }
-  }
-}
-
-void new_tcp_connection(uv_stream_t* server, int status) {
-  static unsigned char new_player_id = 0;
-  uv_loop_t* loop = uv_default_loop();
-  if (status < 0) {
-    fprintf(stderr, "Connection error: %s\n", uv_strerror(status));
-    return;
-  }
-
-  // Initialize the player
-  if (nb_players + 1 > MAX_PLAYERS) return;
-  int index = nb_players;
-  nb_players++;
-  Player* player = &players[index];
-  memset(player, 0, sizeof(Player));
-  player->player_id = new_player_id % MAX_PLAYERS;
-  player->last_packet_tms = time(NULL);
-
-  // Initialize the TCP connection
-  // In the "data" field, we store a pointer to the player - we also store the
-  // connection in the player's tcp_connection field.
-  uv_tcp_t* tcp_connection = malloc(sizeof(uv_tcp_t));
-  uv_tcp_init(loop, tcp_connection);
-  tcp_connection->data = player;
-  player->tcp_connection = tcp_connection;
-  if (uv_accept(server, (uv_stream_t*)tcp_connection) != 0) {
-    kick_player(player);
-    return;
-  }
-
-  // Store the player's IP so we can send them UDP packets later
-  int addrlen = sizeof(player->addr);
-  uv_tcp_getpeername(tcp_connection, (struct sockaddr*)&player->addr, &addrlen);
-
-  new_player_id = new_player_id + 1 % MAX_PLAYERS;
-  INIT_PACKET(S_PACKET_WELCOME);
-  WRITE_BYTE(new_player_id);
-  WRITE_STRING("The soulmate server welcomes you.");
-  SEND_PACKET(player);
-
-  uv_read_start((uv_stream_t*)tcp_connection, tcp_alloc, tcp_read);
-}

+ 0 - 12
src/tcp.h

@@ -1,12 +0,0 @@
-#pragma once
-#include <uv.h>
-
-extern uv_tcp_t* hollowknight_tcp_server;
-
-typedef struct player_s Player;
-void new_tcp_connection(uv_stream_t* server, int status);
-void tcp_broadcast(char* data, int len, Player* source_player);
-void tcp_send(char* data, int len, Player* player);
-
-#define BROADCAST_PACKET_TCP(player) tcp_broadcast(packet, pos, player)
-#define SEND_PACKET(player) tcp_send(packet, pos, (player))

+ 216 - 38
src/udp.c

@@ -1,66 +1,244 @@
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 #include <uv.h>
 
+#include "player.h"
 #include "protocol.h"
 #include "server.h"
 
-uv_udp_t* hollowknight_udp_server = NULL;
+uv_udp_t* hollowknight_server = NULL;
+
+// TODO: make sure we handle libuv errors returned by all functions
+// TODO: add a lot of printfs
+
+// Schedules a packet to be sent to the player on the next server tick
+void send_packet_to_player(Player* player, char* data, int len,
+                           bool is_important) {
+  if (is_important) {
+    if (len > MAX_BYTES_PER_TICK) {
+      printf(
+          "Important packet larger than %d bytes (%d bytes). "
+          "Player: %s\n",
+          MAX_BYTES_PER_TICK, len, player->username);
+    }
+
+    player->nb_must_send_packets += 1;
+    player->must_send_packets =
+        reallocarray(player->must_send_packets, player->nb_must_send_packets,
+                     sizeof(uv_buf_t));
+    player->must_send_packets[player->nb_must_send_packets - 1] =
+        uv_buf_init(data, len);
+    player->outgoing_bytes += len;
+  } else {
+    if (player->outgoing_bytes > MAX_BYTES_PER_TICK) {
+      // Data limit reached for this tick, drop the packet
+      free(data);
+    } else {
+      player->nb_may_send_packets += 1;
+      player->may_send_packets =
+          reallocarray(player->may_send_packets, player->nb_may_send_packets,
+                       sizeof(uv_buf_t));
+      player->may_send_packets[player->nb_may_send_packets - 1] =
+          uv_buf_init(data, len);
+      player->outgoing_bytes += len;
+    }
+  }
+}
+
+void broadcast_packet(Player* source_player, char* packet, int len,
+                      bool same_scene_only, bool is_important) {
+  for (int i = 0; i < MAX_PLAYERS; i++) {
+    if (players[i].username[0] == '\0') continue;
+    if (players[i].id == source_player->id) continue;
+    if (same_scene_only &&
+        (strcmp(players[i].scene, source_player->scene) != 0))
+      continue;
+
+    send_packet_to_player(&players[i], packet, len, is_important);
+  }
+}
+
+struct udp_send_data {
+  unsigned short player_id;
+  uv_udp_send_t write;
+  uv_buf_t* buffers;
+  int nb_buffers;
+};
 
 void end_udp_write(uv_udp_send_t* write, int status) {
   (void)status;
-  free(write->data);
-  free(write);
+  struct udp_send_data* data = write->data;
+  for (int i = 0; i < data->nb_buffers; i++) {
+    free(data->buffers[i].base);
+  }
+  free(data->buffers);
+  free(data);
 }
 
-void udp_broadcast(char* packet, int len, Player* source_player) {
-  // Insert packet length at the start of the packet
-  *((int*)packet) = len - 4;
+void resend_lost_packet(uv_timer_t* handle) {
+  UnackedPacket* up = (UnackedPacket*)handle->data;
+  up->resends++;
+  if (up->resends > MAX_RESENDS) {
+    printf("debug: Dropping lost packet for %s\n", up->player->username);
+    return;
+  }
 
-  for (int i = 0; i < nb_players; i++) {
-    if (players[i].tcp_connection == NULL) continue;
-    if (players[i].player_id == source_player->player_id) continue;
-    if (strcmp(players[i].scene, source_player->scene) != 0) continue;
+  printf("debug: Resending lost packet for %s\n", up->player->username);
 
-    // Copy the packet for each write. TODO: SPEEDUP
-    uv_udp_send_t* write = malloc(sizeof(uv_udp_send_t));
-    write->data = malloc(len);
-    memcpy(write->data, packet, len);
+  struct udp_send_data* out = malloc(sizeof(struct udp_send_data));
+  out->buffers = malloc(sizeof(uv_buf_t));
+  out->nb_buffers = 1;
+  out->write.data = out;
 
-    uv_buf_t wrbuf = uv_buf_init(write->data, len);
-    uv_udp_send(write, hollowknight_udp_server, &wrbuf, 1,
-                (const struct sockaddr*)&players[i].addr, end_udp_write);
-  }
+  clock_gettime(CLOCK_MONOTONIC_COARSE, &up->send_time);
+  uv_udp_send(&out->write, hollowknight_server, out->buffers, out->nb_buffers,
+              (const struct sockaddr*)&up->player->addr, end_udp_write);
 }
 
-void udp_send(char* packet, int len, Player* player) {
-  if (player->tcp_connection == NULL) return;
+void process_tick_for_player(Player* p) {
+  uv_loop_t* loop = uv_default_loop();
+
+  int nb_packets = p->nb_must_send_packets + p->nb_may_send_packets;
+  if (nb_packets == 0) return;
+
+  int outgoing_bytes = 0;
+  struct udp_send_data* out = malloc(sizeof(struct udp_send_data));
+  out->buffers = calloc(nb_packets, sizeof(uv_buf_t));
+  out->write.data = out;
+
+  for (int j = 0; j < p->nb_must_send_packets; j++) {
+    unsigned short* packet_ptr = (unsigned short*)p->must_send_packets[j].base;
+    unsigned short packet_len = packet_ptr[0];
 
-  *((int*)packet) = len - 4;
+    out->buffers[j] = p->must_send_packets[j];
+    out->nb_buffers++;
 
-  // Copy the packet even though we shouldn't. TODO: SPEEDUP
-  uv_udp_send_t* write = malloc(sizeof(uv_udp_send_t));
-  write->data = malloc(len);
-  memcpy(write->data, packet, len);
+    packet_ptr[1] = p->local_sequence_number;
+    p->local_sequence_number = (p->local_sequence_number + 1) % USHRT_MAX;
+
+    packet_ptr[2] = p->ack;
+    unsigned int* ack_field = (unsigned int*)&packet_ptr[3];
+    *ack_field = p->ack_field;
+
+    outgoing_bytes += packet_len;
+
+    // Add copy of the packet to unacked packet list
+    // It will be resent after player->rtt * 2 milliseconds unless acked
+    p->unacked_packets = reallocarray(
+        p->unacked_packets, p->nb_unacked_packets + 1, sizeof(UnackedPacket));
+    UnackedPacket* up = &p->unacked_packets[p->nb_unacked_packets];
+    p->nb_unacked_packets++;
+    char* packet_cpy = malloc(p->must_send_packets[j].len);
+    memcpy(packet_cpy, p->must_send_packets[j].base,
+           p->must_send_packets[j].len);
+    clock_gettime(CLOCK_MONOTONIC_COARSE, &up->send_time);
+    up->player = p;
+    up->sequence = packet_ptr[1];
+    up->buffer = uv_buf_init(packet_cpy, p->must_send_packets[j].len);
+    uv_timer_init(loop, &up->timer);
+    up->timer.data = up;
+    uv_timer_start(&up->timer, resend_lost_packet, p->rtt * 2, p->rtt * 2);
+
+    if (p->nb_unacked_packets > MAX_UNACKED_PACKETS) {
+      kick_player(p, true);
+      return;
+    }
+  }
 
-  uv_buf_t wrbuf = uv_buf_init(write->data, len);
-  uv_udp_send(write, hollowknight_udp_server, &wrbuf, 1,
-              (const struct sockaddr*)&player->addr, end_udp_write);
+  for (int j = 0; j < p->nb_may_send_packets; j++) {
+    unsigned short* packet_ptr = (unsigned short*)p->may_send_packets[j].base;
+    unsigned short packet_len = packet_ptr[0];
+    if (outgoing_bytes + packet_len > MAX_BYTES_PER_TICK) break;
+
+    out->buffers[p->nb_must_send_packets + j] = p->may_send_packets[j];
+    out->nb_buffers++;
+
+    packet_ptr[1] = p->local_sequence_number;
+    p->local_sequence_number = (p->local_sequence_number + 1) % USHRT_MAX;
+
+    packet_ptr[2] = p->ack;
+    unsigned int* ack_field = (unsigned int*)&packet_ptr[3];
+    *ack_field = p->ack_field;
+
+    outgoing_bytes += packet_len;
+  }
+
+  free(p->must_send_packets);
+  p->must_send_packets = NULL;
+  p->nb_must_send_packets = 0;
+  free(p->may_send_packets);
+  p->may_send_packets = NULL;
+  p->nb_may_send_packets = 0;
+
+  uv_udp_send(&out->write, hollowknight_server, out->buffers, out->nb_buffers,
+              (const struct sockaddr*)&p->addr, end_udp_write);
 }
 
-void udp_alloc(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf) {
+void process_tick(uv_timer_t* handle) {
   (void)handle;
-  buf->base = malloc(suggested_size);
-  buf->len = suggested_size;
+
+  for (int i = 0; i < MAX_PLAYERS; i++) {
+    if (players[i].username[0] == '\0') continue;
+    process_tick_for_player(&players[i]);
+  }
 }
 
 void udp_read(uv_udp_t* req, ssize_t nread, const uv_buf_t* buf,
               const struct sockaddr* addr, unsigned flags) {
-  (void)addr;
-  (void)flags;
-  (void)req;
-  if (nread > 0) {
-    read_udp_packet(buf->base, nread);
+  // We need a remote IP address to do anything with the packet.
+  if (addr == NULL || nread <= 0) {
+    if ((flags & UV_UDP_MMSG_FREE) && buf->base) {
+      free(buf->base);
+    }
+    return;
+  }
+
+  // Get player from UDP handle address
+  req->data = NULL;
+  for (int i = 0; i < MAX_PLAYERS; i++) {
+    // TODO: double check ss_family vs sa_family
+    if (players[i].addr.ss_family != addr->sa_family) continue;
+
+    if (addr->sa_family == AF_INET) {
+      struct sockaddr_in* one = (struct sockaddr_in*)addr;
+      struct sockaddr_in* two = (struct sockaddr_in*)&players[i].addr;
+      if (one->sin_addr.s_addr != two->sin_addr.s_addr) continue;
+      if (one->sin_port != two->sin_port) continue;
+
+      req->data = &players[i];
+      break;
+    } else if (addr->sa_family == AF_INET6) {
+      struct sockaddr_in6* one = (struct sockaddr_in6*)addr;
+      struct sockaddr_in6* two = (struct sockaddr_in6*)&players[i].addr;
+      if (memcmp(one->sin6_addr.s6_addr, two->sin6_addr.s6_addr,
+                 sizeof(one->sin6_addr.s6_addr)) != 0)
+        continue;
+      if (one->sin6_port != two->sin6_port) continue;
+
+      req->data = &players[i];
+      break;
+    }
+  }
+
+  // No player found, pick the first available spot
+  if (req->data == NULL) {
+    for (int i = 0; i < MAX_PLAYERS; i++) {
+      if (players[i].username[0] == '\0') {
+        players[i].rtt = 200;
+        req->data = &players[i];
+        break;
+      }
+    }
   }
-  free(buf->base);
-}
+
+  if (req->data != NULL) {
+    Player* player = (Player*)req->data;
+    player->last_packet_tms = time(NULL);
+
+    int pos = 0;
+    while (nread - pos > 0) {
+      pos += handle_packet(player, buf->base + pos, nread - pos);
+    }
+  }
+}

+ 19 - 6
src/udp.h

@@ -1,12 +1,25 @@
 #pragma once
+#include <stdbool.h>
 
-extern uv_udp_t* hollowknight_udp_server;
+extern uv_udp_t* hollowknight_server;
 
-void udp_broadcast(char* packet, int len, Player* source_player);
-void udp_send(char* packet, int len, Player* player);
-void udp_alloc(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf);
+void broadcast_packet(Player* source_player, char* packet, int len,
+                      bool same_scene_only, bool is_important);
+void send_packet_to_player(Player* player, char* data, int len,
+                           bool is_important);
+void process_tick(uv_timer_t* handle);
 void udp_read(uv_udp_t* req, ssize_t nread, const uv_buf_t* buf,
               const struct sockaddr* addr, unsigned flags);
 
-#define BROADCAST_PACKET_UDP(player) udp_broadcast(packet, pos, player)
-#define SEND_UDP_PACKET(player) udp_send(packet, pos, player)
+#define PACKET_SEND(player) \
+  send_packet_to_player(player, packet, out_pos, false)
+#define SCENE_BROADCAST(player) \
+  broadcast_packet(player, packet, out_pos, true, false)
+#define SERVER_BROADCAST(player) \
+  broadcast_packet(player, packet, out_pos, false, false)
+#define IMPORTANT_PACKET_SEND(player) \
+  send_packet_to_player(player, packet, out_pos, true)
+#define IMPORTANT_SCENE_BROADCAST(player) \
+  broadcast_packet(player, packet, out_pos, true, true)
+#define IMPORTANT_SERVER_BROADCAST(player) \
+  broadcast_packet(player, packet, out_pos, false, true)