Host options in the lobby: public, bots and their skill

Y in a hosted game's lobby opens a panel to make the game public, choose
how many bots join (none by default, up to 15) and how well they play
(bots.skill: easy, normal, hard; hard is the first bots' play, normal a
little slower to notice, turn and aim). Integer settings can now be
written to config.toml as booleans could.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

port/linux/game/bots.c

@@ -0,0 +1,586 @@
+/*
+BOTS.C
+
+Bots in multiplayer (the VR port's): players of the host that it drives
+itself. They are the players of machines of the host's own that nothing
+connects to (network_server_manager.c: bots.count of them, added in the
+lobby), so every machine sees them as it sees any other machine's players,
+and their input goes where a client's does: every tick, the host makes each
+bot's player_action and takes it as a client's input
+(update_server_handle_distributed_input).
+
+A bot looks for the nearest enemy it can see, turns to it no faster than a
+player would (and not quite right), closes on it weaving from side to side
+and fires while it is on target. With none in sight it hunts the nearest
+enemy, or else roams to a point picked at random near someone. It finds its
+way with the game's own pathfinding (ai/path.c: the maps' pathfinding
+surfaces), as the campaign's actors do: a path a few times a second, whose
+next point it walks to, looking where it goes; where no path is found it
+walks straight at the goal, jumping and turning off when it is stuck.
+*/
+
+#include "cseries.h"
+#include "game/game.h"
+#include "game/game_engine.h"
+#include "game/players.h"
+#include "game/player_queues_new.h"
+#include "objects/objects.h"
+#include "physics/collisions.h"
+#include "ai/path.h"
+#include "units/bipeds.h"
+#include "scenario/scenario.h"
+#include "structures/structure_bsp_definitions.h"
+#include "units/units.h"
+#include "network_distributed.h"
+
+#include <math.h>
+
+void platform_log(char const *format, ...);
+long config_integer(char const *name);
+boolean network_game_server_is_bot_machine(long machine_index);
+
+/* ---------- constants */
+
+enum
+{
+	MAXIMUM_BOTS = 16,
+	/* how often a bot finds its path again (ticks) */
+	PATH_REFRESH_TICKS = 15,
+};
+
+/* how near a path's point counts as reached, and the goal (world units) */
+#define BOT_STEP_RADIUS 0.4f
+#define BOT_GOAL_RADIUS 1.0f
+
+/* how far a bot sees and shoots (world units), and how near it closes */
+#define BOT_FIRE_RANGE 30.0f
+#define BOT_CLOSE_RANGE 3.0f
+/* how far off target it still fires (radians) */
+#define BOT_FIRE_CONE 0.08f
+
+/* ---------- structures */
+
+struct bot
+{
+	long player_index;
+	long target_unit_index;
+	short target_seen_ticks;
+	real yaw;
+	real pitch;
+	real aim_error_yaw;
+	real aim_error_pitch;
+	short error_ticks;
+	real_point3d last_position;
+	short stuck_ticks;
+	real wander_yaw;
+	short weave_phase;
+	/* where it is going, and the way there */
+	boolean has_goal;
+	real_point3d goal;
+	long goal_time;
+	long path_time;
+	struct path_result path;
+};
+
+/* ---------- globals */
+
+/* (one search at a time, shared: 80 kB) */
+static struct path_state bot_path_state;
+
+static struct
+{
+	boolean map_logged;
+	struct bot bots[MAXIMUM_BOTS];
+	long seed;
+	long logged_time;
+	long paths_found;
+	long paths_failed;
+	/* how well they play (bots.skill, as the game began) */
+	short reaction_ticks;
+	real turn_rate;
+	real sight_range;
+	real aim_error;
+} bots;
+
+/* easy, normal, hard: the ticks a bot takes to notice an enemy, how fast it
+turns (radians a tick), how far it sees and how far off its aim wanders */
+static struct
+{
+	short reaction_ticks;
+	real turn_rate;
+	real sight_range;
+	real aim_error;
+} const bot_skills[] =
+{
+	{ 20, 2.2f / 30.0f, 25.0f, 3.0f },
+	{ 13, 2.8f / 30.0f, 32.0f, 1.8f },
+	{ 9, 3.5f / 30.0f, 40.0f, 1.0f },
+};
+
+/* ---------- private code */
+
+static real bot_random(
+	void)
+{
+	bots.seed = bots.seed * 1103515245 + 12345;
+	return (real)((bots.seed >> 16) & 0x7FFF) / 32767.0f;
+}
+
+static real bot_angle_difference(
+	real to,
+	real from)
+{
+	real difference = to - from;
+
+	while (difference > _pi)
+		difference -= 2.0f * _pi;
+	while (difference < -_pi)
+		difference += 2.0f * _pi;
+	return difference;
+}
+
+static boolean bot_can_see(
+	long unit_index,
+	real_point3d const *from,
+	real_point3d const *to)
+{
+	struct collision_result collision;
+	real_vector3d vector;
+
+	vector.i = to->x - from->x;
+	vector.j = to->y - from->y;
+	vector.k = to->z - from->z;
+	return !collision_test_vector(FLAG(_collision_test_structure_bit) | FLAG(_collision_test_front_facing_surfaces_bit),
+		from, &vector, unit_index, &collision);
+}
+
+/* the nearest enemy unit the bot can see, or NONE */
+static long bot_find_target(
+	struct player_datum const *player,
+	real_point3d const *eye)
+{
+	boolean teams = game_engine_has_teams();
+	long best = NONE;
+	real best_distance = bots.sight_range;
+	short index;
+
+	for (index = 0; index < MAXIMUM_TRACKED_PLAYERS; index++)
+	{
+		struct player_datum *other = distributed_player(index);
+		long unit_index;
+		real_point3d head;
+		real distance;
+
+		if (!other || other == player || (teams && other->team_index == player->team_index))
+			continue;
+		unit_index = distributed_living_unit(other);
+		if (unit_index == NONE)
+			continue;
+		unit_get_camera_position(unit_index, &head);
+		distance = distance3d(eye, &head);
+		if (distance < best_distance && bot_can_see(player->unit_index, eye, &head))
+		{
+			best = unit_index;
+			best_distance = distance;
+		}
+	}
+	return best;
+}
+
+/* the way from where the bot's unit stands to the goal (FALSE: none) */
+static boolean bot_find_path(
+	struct bot *bot,
+	long unit_index)
+{
+	struct path_input input;
+	real_point3d start;
+	long start_surface = biped_find_pathfinding_surface_index(unit_index, &start);
+	real_point3d goal = bot->goal;
+	long goal_surface = NONE;
+
+	bot->path.valid = FALSE;
+	if (start_surface == NONE)
+		return FALSE;
+	/* (the goal's surface: under it, as a biped would stand there) */
+	{
+		struct collision_result collision;
+		real_vector3d down = { 0.0f, 0.0f, -3.0f };
+		real_point3d above = goal;
+
+		above.z += 0.5f;
+		if (collision_test_vector(FLAG(_collision_test_structure_bit) | FLAG(_collision_test_front_facing_surfaces_bit),
+			&above, &down, NONE, &collision))
+		{
+			goal = collision.point;
+			goal_surface = collision.surface_index;
+		}
+	}
+	if (goal_surface == NONE)
+		return FALSE;
+	path_input_new(&input, 0.25f, FALSE, unit_index);
+	path_input_set_start(&input, &start, start_surface);
+	path_state_new(&input, &bot_path_state, NULL);
+	path_state_destination(&bot_path_state, &goal, goal_surface, BOT_GOAL_RADIUS);
+	if (!path_state_find(&bot_path_state) || !path_state_build_path(&bot_path_state, &bot->path))
+	{
+		bot->path.valid = FALSE;
+		bots.paths_failed++;
+		return FALSE;
+	}
+	bots.paths_found += bot->path.valid != FALSE;
+	return bot->path.valid;
+}
+
+/* the point it walks to now: the path's next, or the goal itself */
+static boolean bot_next_point(
+	struct bot *bot,
+	long unit_index,
+	real_point3d const *position,
+	real_point3d *point)
+{
+	if (!bot->has_goal)
+		return FALSE;
+	if (game_time_get() - bot->path_time >= PATH_REFRESH_TICKS || game_time_get() < bot->path_time)
+	{
+		bot->path_time = game_time_get();
+		bot_find_path(bot, unit_index);
+	}
+	if (bot->path.valid)
+	{
+		while (bot->path.step_index < bot->path.step_count)
+		{
+			struct path_step const *step = &bot->path.steps[(short)bot->path.step_index];
+			real dx = step->point.x - position->x;
+			real dy = step->point.y - position->y;
+
+			if (dx * dx + dy * dy > BOT_STEP_RADIUS * BOT_STEP_RADIUS)
+			{
+				*point = step->point;
+				return TRUE;
+			}
+			bot->path.step_index++;
+		}
+		/* (the steps done: on to the end, or a path found anew soon) */
+		if (!bot->path.steps_finish_path && game_time_get() - bot->path_time > 5)
+			bot->path_time = game_time_get() - PATH_REFRESH_TICKS;
+		*point = bot->path.endpoint.point;
+		return TRUE;
+	}
+	*point = bot->goal;
+	return TRUE;
+}
+
+/* a goal when none is in sight: the nearest enemy, or somewhere near
+someone at random */
+static void bot_choose_goal(
+	struct bot *bot,
+	struct player_datum const *player,
+	real_point3d const *position)
+{
+	boolean teams = game_engine_has_teams();
+	real best_distance = 1000000.0f;
+	short index;
+	boolean found = FALSE;
+
+	for (index = 0; index < MAXIMUM_TRACKED_PLAYERS; index++)
+	{
+		struct player_datum *other = distributed_player(index);
+		long unit_index;
+		real_point3d origin;
+		real distance;
+
+		if (!other || other == player || (teams && other->team_index == player->team_index))
+			continue;
+		unit_index = distributed_living_unit(other);
+		if (unit_index == NONE)
+			continue;
+		object_get_origin(unit_index, &origin);
+		distance = distance3d(position, &origin);
+		if (distance < best_distance)
+		{
+			best_distance = distance;
+			bot->goal = origin;
+			found = TRUE;
+		}
+	}
+	if (!found)
+	{
+		/* (no enemy alive: a few metres off, somewhere) */
+		real angle = bot_random() * 2.0f * _pi;
+
+		bot->goal = *position;
+		bot->goal.x += (real)cos(angle) * 5.0f;
+		bot->goal.y += (real)sin(angle) * 5.0f;
+	}
+	bot->has_goal = TRUE;
+	bot->goal_time = game_time_get();
+	bot->path_time = game_time_get() - PATH_REFRESH_TICKS;
+}
+
+/* the throttle that walks a unit facing yaw towards a point */
+static void bot_walk_to(
+	struct player_action *action,
+	real yaw,
+	real_point3d const *position,
+	real_point3d const *point)
+{
+	real dx = point->x - position->x;
+	real dy = point->y - position->y;
+	real length = (real)sqrt(dx * dx + dy * dy);
+
+	if (length < 0.001f)
+		return;
+	dx /= length;
+	dy /= length;
+	/* (forward along the facing; left, its strafe's positive) */
+	action->throttle.i = dx * (real)cos(yaw) + dy * (real)sin(yaw);
+	action->throttle.j = -dx * (real)sin(yaw) + dy * (real)cos(yaw);
+}
+
+static void bot_think(
+	struct bot *bot,
+	struct player_datum *player,
+	struct player_action *action)
+{
+	struct unit_datum *unit = unit_try_and_get(player->unit_index);
+	real_point3d eye;
+	real_point3d position;
+	real wanted_yaw;
+	real wanted_pitch = 0.0f;
+	boolean firing = FALSE;
+	real moved;
+
+	csmemset(action, 0, sizeof(*action));
+	action->desired_weapon_index = NONE;
+	action->desired_grenade_index = NONE;
+	action->desired_zoom_level = NONE;
+	if (!unit || unit->object.parent_object_index != NONE)
+	{
+		bot->target_unit_index = NONE;
+		return;
+	}
+	action->desired_weapon_index = unit->unit.current_weapon_index;
+	action->desired_grenade_index = unit->unit.current_grenade_index;
+	unit_get_camera_position(player->unit_index, &eye);
+	object_get_origin(player->unit_index, &position);
+	/* (where it faces now, the first time) */
+	if (bot->error_ticks == 0 && bot->yaw == 0.0f && bot->pitch == 0.0f)
+	{
+		bot->yaw = (real)atan2(unit->unit.aiming_vector.j, unit->unit.aiming_vector.i);
+		bot->wander_yaw = bot->yaw;
+	}
+
+	/* the enemy: noticed after a moment, kept while in sight */
+	{
+		long target = bot_find_target(player, &eye);
+
+		if (target != bot->target_unit_index)
+		{
+			bot->target_unit_index = target;
+			bot->target_seen_ticks = 0;
+		}
+		else if (target != NONE && bot->target_seen_ticks < SHORT_MAX)
+		{
+			bot->target_seen_ticks++;
+		}
+	}
+	/* (its aim wanders a little, anew now and then) */
+	if (--bot->error_ticks <= 0)
+	{
+		bot->error_ticks = 10 + (short)(bot_random() * 20.0f);
+		bot->aim_error_yaw = (bot_random() - 0.5f) * 0.06f * bots.aim_error;
+		bot->aim_error_pitch = (bot_random() - 0.5f) * 0.04f * bots.aim_error;
+	}
+
+	if (bot->target_unit_index != NONE && bot->target_seen_ticks >= bots.reaction_ticks)
+	{
+		real_point3d head;
+		real dx, dy, dz, flat, distance;
+
+		unit_get_camera_position(bot->target_unit_index, &head);
+		/* (at the chest) */
+		head.z -= 0.15f;
+		dx = head.x - eye.x;
+		dy = head.y - eye.y;
+		dz = head.z - eye.z;
+		flat = (real)sqrt(dx * dx + dy * dy);
+		distance = (real)sqrt(dx * dx + dy * dy + dz * dz);
+		wanted_yaw = (real)atan2(dy, dx) + bot->aim_error_yaw;
+		wanted_pitch = (real)atan2(dz, flat) + bot->aim_error_pitch;
+		/* closes on it along its way, weaving, until near */
+		bot->weave_phase++;
+		if (distance > BOT_CLOSE_RANGE)
+		{
+			real_point3d point;
+
+			object_get_origin(bot->target_unit_index, &bot->goal);
+			bot->has_goal = TRUE;
+			if (bot_next_point(bot, player->unit_index, &position, &point))
+				bot_walk_to(action, bot->yaw, &position, &point);
+		}
+		action->throttle.j += (real)sin(bot->weave_phase * 0.08f) * 0.6f;
+		firing = distance < BOT_FIRE_RANGE &&
+			fabsf(bot_angle_difference(wanted_yaw, bot->yaw)) < BOT_FIRE_CONE &&
+			fabsf(wanted_pitch - bot->pitch) < BOT_FIRE_CONE;
+		/* (a melee blow when it is upon it) */
+		if (distance < 1.0f)
+			SET_FLAG(action->control_flags, _unit_control_use_equipment_bit, TRUE);
+	}
+	else
+	{
+		real_point3d point;
+
+		/* hunts, or roams: along its way, looking where it goes */
+		if (!bot->has_goal || game_time_get() - bot->goal_time > 90 ||
+			distance3d(&position, &bot->goal) < BOT_GOAL_RADIUS)
+		{
+			bot_choose_goal(bot, player, &position);
+		}
+		wanted_yaw = bot->wander_yaw;
+		if (bot_next_point(bot, player->unit_index, &position, &point))
+		{
+			real dx = point.x - position.x;
+			real dy = point.y - position.y;
+
+			if (dx * dx + dy * dy > 0.0001f)
+				bot->wander_yaw = wanted_yaw = (real)atan2(dy, dx);
+			bot_walk_to(action, bot->yaw, &position, &point);
+		}
+		if (bot->stuck_ticks > 20)
+		{
+			/* (stuck: somewhere else) */
+			bot_choose_goal(bot, player, &position);
+			bot->goal.x += (bot_random() - 0.5f) * 6.0f;
+			bot->goal.y += (bot_random() - 0.5f) * 6.0f;
+			bot->stuck_ticks = 0;
+		}
+	}
+
+	/* turned no faster than a player turns */
+	{
+		real turn = bot_angle_difference(wanted_yaw, bot->yaw);
+
+		bot->yaw += PIN(turn, -bots.turn_rate, bots.turn_rate);
+		bot->pitch += PIN(wanted_pitch - bot->pitch, -bots.turn_rate, bots.turn_rate);
+		bot->pitch = PIN(bot->pitch, -1.4f, 1.4f);
+		while (bot->yaw > _pi)
+			bot->yaw -= 2.0f * _pi;
+		while (bot->yaw < -_pi)
+			bot->yaw += 2.0f * _pi;
+	}
+	action->desired_facing.yaw = bot->yaw < 0.0f ? bot->yaw + 2.0f * _pi : bot->yaw;
+	action->desired_facing.pitch = bot->pitch;
+	if (firing)
+	{
+		action->primary_trigger = 1.0f;
+		SET_FLAG(action->control_flags, _unit_control_weapon_primary_trigger_bit, TRUE);
+	}
+
+	/* stuck: hardly moved while walking (it jumps, and then turns) */
+	moved = distance3d(&position, &bot->last_position);
+	bot->last_position = position;
+	action->throttle.i = PIN(action->throttle.i, -1.0f, 1.0f);
+	action->throttle.j = PIN(action->throttle.j, -1.0f, 1.0f);
+	if ((fabsf(action->throttle.i) > 0.5f || fabsf(action->throttle.j) > 0.5f) && moved < 0.02f)
+	{
+		bot->stuck_ticks++;
+		if (bot->stuck_ticks == 8)
+			SET_FLAG(action->control_flags, _unit_control_jump_bit, TRUE);
+	}
+	else
+	{
+		bot->stuck_ticks = 0;
+	}
+}
+
+/* the bot of a player, made when first needed */
+static struct bot *bot_get(
+	long player_index)
+{
+	short index;
+	struct bot *free_bot = NULL;
+
+	for (index = 0; index < MAXIMUM_BOTS; index++)
+	{
+		if (bots.bots[index].player_index == player_index)
+			return &bots.bots[index];
+		if (bots.bots[index].player_index == NONE && !free_bot)
+			free_bot = &bots.bots[index];
+	}
+	if (free_bot)
+	{
+		csmemset(free_bot, 0, sizeof(*free_bot));
+		free_bot->player_index = player_index;
+		free_bot->target_unit_index = NONE;
+	}
+	return free_bot;
+}
+
+/* ---------- public code */
+
+void bots_new_game(
+	void)
+{
+	short index;
+
+	bots.map_logged = FALSE;
+	for (index = 0; index < MAXIMUM_BOTS; index++)
+		bots.bots[index].player_index = NONE;
+	bots.seed = 12345;
+	bots.logged_time = 0;
+	{
+		long skill = PIN(config_integer("bots.skill"), 0, (long)NUMBEROF(bot_skills) - 1);
+
+		bots.reaction_ticks = bot_skills[skill].reaction_ticks;
+		bots.turn_rate = bot_skills[skill].turn_rate;
+		bots.sight_range = bot_skills[skill].sight_range;
+		bots.aim_error = bot_skills[skill].aim_error;
+	}
+}
+
+/* (the host) after each tick: each bot's input for the next */
+void bots_tick(
+	void)
+{
+	short index;
+	short count = 0;
+
+	if (!bots.map_logged)
+	{
+		struct structure_bsp *bsp = global_structure_bsp_get();
+
+		bots.map_logged = TRUE;
+		if (bsp)
+		{
+			platform_log("bots: the map's pathfinding: %ld surfaces, %ld edges",
+				bsp->pathfinding_surfaces.count, bsp->pathfinding_edges.count);
+		}
+	}
+	for (index = 0; index < MAXIMUM_TRACKED_PLAYERS; index++)
+	{
+		struct player_datum *player = distributed_player(index);
+		struct bot *bot;
+		struct player_action action;
+		unsigned short control_flags;
+
+		if (!player || player->local_player_index != NONE ||
+			!network_game_server_is_bot_machine(player->network_player_data.machine_index))
+		{
+			continue;
+		}
+		bot = bot_get(DATUM_INDEX_NEW(index, player->identifier));
+		if (!bot)
+			continue;
+		bot_think(bot, player, &action);
+		control_flags = (unsigned short)action.control_flags;
+		update_server_handle_distributed_input(DATUM_INDEX_NEW(index, player->identifier), game_time_get(), &action,
+			&control_flags, 1);
+		count++;
+	}
+	if (count && game_time_get() - bots.logged_time >= 300)
+	{
+		bots.logged_time = game_time_get();
+		platform_log("bots: driving %d; paths found %ld, not %ld", (int)count, bots.paths_found, bots.paths_failed);
+		bots.paths_found = bots.paths_failed = 0;
+	}
+}

port/linux/game/network_distributed.c

@@ -3051,6 +3051,7 @@ void network_distributed_new_game(
 	network_objects_new_game();
 	network_damage_new_game();
 	network_vr_new_game();
+	bots_new_game();
 }
 
 /* after each tick (game_time.c) */
@@ -3093,6 +3094,7 @@ void network_distributed_tick(
 		distributed_statistics_due = FALSE;
 		distributed_host_send_players();
 		network_vr_tick();
+		bots_tick();
 		distributed_send_pickups();
 		if (game_time_get() % GAME_STATE_INTERVAL_TICKS == 0)
 			distributed_send_game_state(NONE);

port/linux/game/network_distributed.h

@@ -236,4 +236,8 @@ void network_vr_tick(void);
 word network_vr_entry_size(void);
 void network_vr_handle_poses(long machine_index, void const *entries, short count);
 
+/* bots (bots.c) */
+void bots_new_game(void);
+void bots_tick(void);
+
 #endif // __NETWORK_DISTRIBUTED_H

port/linux/src/p2p.c

@@ -331,6 +331,8 @@ static struct
 	unsigned char join_host_hash[P2P_KEY_HASH_SIZE];
 	unsigned char join_token[P2P_TOKEN_SIZE];
 	unsigned long join_time;
+	/* how the latest join goes, for the menus (p2p_join_state) */
+	int join_state;
 
 	char clipboard[P2P_LINK_SIZE];
 	int has_clipboard;
@@ -840,6 +842,12 @@ static void drop_peer(struct peer *peer, const char *reason)
 	struct retired_session *retired = &p2p.retired[p2p.retired_next++ % MAXIMUM_RETIRED_SESSIONS];
 	int ask_again = p2p.joining && peer->is_host && !memcmp(peer->identifier, p2p.join_host, P2P_IDENTIFIER_SIZE);
 
+	if (peer->is_host && !memcmp(peer->identifier, p2p.join_host, P2P_IDENTIFIER_SIZE) &&
+		p2p.join_state != P2P_JOIN_NONE)
+	{
+		p2p.join_state = peer->connected ? P2P_JOIN_LOST : P2P_JOIN_BLOCKED;
+	}
+
 	platform_log("Internet play: %s %s: %s", peer->is_host ? "host" : "player", peer->name, reason);
 	if (peer->connected)
 	{
@@ -1029,6 +1037,8 @@ static void peer_heard(struct peer *peer, unsigned long address, unsigned short
 			address_text(address, port, text));
 		if (peer->is_host)
 		{
+			if (!memcmp(p2p.join_host, peer->identifier, P2P_IDENTIFIER_SIZE) && p2p.join_state != P2P_JOIN_NONE)
+				p2p.join_state = P2P_JOIN_CONNECTED;
 			if (p2p.joining && !memcmp(p2p.join_host, peer->identifier, P2P_IDENTIFIER_SIZE))
 			{
 				p2p.joining = 0;
@@ -2298,6 +2308,7 @@ static int join_invite(const char *text)
 	memcpy(p2p.join_host_hash, hash, sizeof(hash));
 	memcpy(p2p.join_token, token, sizeof(token));
 	p2p.join_requested = 1;
+	p2p.join_state = P2P_JOIN_REACHING;
 	return 1;
 }
 
@@ -2314,10 +2325,93 @@ int p2p_join_invite(const char *text)
 	return result > 0;
 }
 
+int p2p_join_code(char *text, int size)
+{
+	int result;
+
+	pthread_mutex_lock(&p2p_lock);
+	result = p2p.running && p2p_code_hosted(text, size);
+	pthread_mutex_unlock(&p2p_lock);
+	return result;
+}
+
+int p2p_join_with_code(const char *typed)
+{
+	int result;
+
+	pthread_mutex_lock(&p2p_lock);
+	result = p2p.running && p2p_code_look_up(typed);
+	pthread_mutex_unlock(&p2p_lock);
+	return result;
+}
+
+int p2p_join_code_status(void)
+{
+	int status;
+
+	pthread_mutex_lock(&p2p_lock);
+	status = p2p.running ? p2p_code_status() : P2P_CODE_OFFLINE;
+	pthread_mutex_unlock(&p2p_lock);
+	return status;
+}
+
+void p2p_set_public_game(int public_game)
+{
+	pthread_mutex_lock(&p2p_lock);
+	p2p_list_set_public(public_game);
+	pthread_mutex_unlock(&p2p_lock);
+}
+
+int p2p_public_game(void)
+{
+	int result;
+
+	pthread_mutex_lock(&p2p_lock);
+	result = p2p_list_public();
+	pthread_mutex_unlock(&p2p_lock);
+	return result;
+}
+
+void p2p_set_game_description(const char *name, const char *map, const char *mode, int players,
+	int maximum_players)
+{
+	pthread_mutex_lock(&p2p_lock);
+	p2p_list_set_description(name, map, mode, players, maximum_players);
+	pthread_mutex_unlock(&p2p_lock);
+}
+
+int p2p_public_games(struct p2p_public_game *games, int maximum)
+{
+	int count;
+
+	pthread_mutex_lock(&p2p_lock);
+	count = p2p.running ? p2p_list_games(games, maximum) : 0;
+	pthread_mutex_unlock(&p2p_lock);
+	return count;
+}
+
+int p2p_join_state(void)
+{
+	int state;
+
+	pthread_mutex_lock(&p2p_lock);
+	state = p2p.running ? p2p.join_state : P2P_JOIN_NONE;
+	pthread_mutex_unlock(&p2p_lock);
+	return state;
+}
+
+void p2p_join_code_clear_status(void)
+{
+	pthread_mutex_lock(&p2p_lock);
+	p2p_code_clear_status();
+	pthread_mutex_unlock(&p2p_lock);
+}
+
 void p2p_invite_received(const char *text)
 {
-	/* (an older version's is logged as such) */
-	if (!join_invite(text))
+	/* (an older version's is logged as such; a join code is looked up,
+	p2p_code.c) */
+	if (!join_invite(text) && !p2p_code_look_up(text))
 		platform_log("Internet play: that is not an invite");
 }
 
@@ -2343,6 +2437,8 @@ static void update_joining(void)
 	{
 		p2p.joining = 0;
 		p2p_signal_stop_joining();
+		if (p2p.join_state == P2P_JOIN_REACHING)
+			p2p.join_state = P2P_JOIN_NO_ANSWER;
 		platform_log("Internet play: no answer from the invite's host; it may have stopped hosting or quit");
 	}
 }
@@ -2382,6 +2478,14 @@ static void update_hosting(void)
 		p2p.stun_started = 1;
 		p2p_signal_start();
 		p2p_signal_host(p2p.token);
+		{
+			/* (and a join code for it, p2p_code.c) */
+			unsigned char bytes[P2P_KEY_HASH_SIZE + P2P_TOKEN_SIZE];
+
+			p2p_key_hash(p2p_public_key(), bytes);
+			memcpy(bytes + P2P_KEY_HASH_SIZE, p2p.token, P2P_TOKEN_SIZE);
+			p2p_code_host(bytes);
+		}
 		platform_log("Internet play: hosting. Invite players with this link (it only works while this "
 			"copy of the game runs): %s", p2p.invite);
 		if (!p2p.invite_copied)
@@ -2396,6 +2500,7 @@ static void update_hosting(void)
 	{
 		p2p.hosting = 0;
 		p2p_signal_stop_hosting();
+		p2p_code_stop_hosting();
 		p2p_discord_set_hosting(NULL, 0, 0);
 	}
 	if (p2p.hosting)

port/linux/src/p2p.h

@@ -26,6 +26,61 @@ int p2p_hand_off_invite(void);
 words around it. Returns nonzero if it held an invite */
 int p2p_join_invite(const char *text);
 
+/* Join codes (p2p_code.c): the hosted game's code as XXXX-XXXX (0 if
+none); looking a typed one up, which then joins as its invite does (0 if
+it is not a code, or internet play is off); and how the look up goes */
+enum
+{
+	P2P_CODE_IDLE,
+	P2P_CODE_LOOKING,
+	P2P_CODE_FOUND,
+	P2P_CODE_NOT_FOUND,
+	P2P_CODE_INVALID,
+	P2P_CODE_OWN,
+	P2P_CODE_OFFLINE,
+};
+int p2p_join_code(char *text, int size);
+int p2p_join_with_code(const char *typed);
+int p2p_join_code_status(void);
+void p2p_join_code_clear_status(void);
+/* how the latest join of an invite or code goes (the VR port's, for the
+menus): reaching the host, connected (its game is in the system link list),
+or why not */
+enum
+{
+	P2P_JOIN_NONE,
+	P2P_JOIN_REACHING,
+	P2P_JOIN_CONNECTED,
+	P2P_JOIN_NO_ANSWER,
+	P2P_JOIN_BLOCKED,
+	P2P_JOIN_LOST,
+};
+int p2p_join_state(void);
+
+/* Public games (p2p_list.c): the hosted game listed for anyone or not, and
+what it is (the game's server, as it changes); and the games others list,
+joined by their codes (p2p_join_with_code) */
+enum
+{
+	P2P_PUBLIC_NAME_SIZE = 16,
+	P2P_PUBLIC_MAP_SIZE = 32,
+	P2P_PUBLIC_MODE_SIZE = 24,
+};
+struct p2p_public_game
+{
+	char name[P2P_PUBLIC_NAME_SIZE];
+	char map[P2P_PUBLIC_MAP_SIZE];
+	char mode[P2P_PUBLIC_MODE_SIZE];
+	char code[12];
+	int players;
+	int maximum_players;
+};
+void p2p_set_public_game(int public_game);
+int p2p_public_game(void);
+void p2p_set_game_description(const char *name, const char *map, const char *mode, int players,
+	int maximum_players);
+int p2p_public_games(struct p2p_public_game *games, int maximum);
+
 /* this machine's identifier, which its XNADDR carries (6 bytes) */
 const unsigned char *p2p_identifier(void);
 /* the address the game reaches the machine with this identifier at, if it

port/linux/src/p2p_code.c

@@ -0,0 +1,317 @@
+/*
+P2P_CODE.C
+
+Join codes (the VR port's): a short code that stands for a hosted game's
+invite (p2p.c), for a player who cannot pass a link on, as in a headset,
+where a link is not copied out and 64 hex digits are not typed in.
+
+- A host makes a code when it starts hosting: 8 characters of Crockford's
+  base 32 (40 bits), shown as XXXX-XXXX (ui_join_code.c draws it in the
+  lobby). It lasts while the host hosts.
+- From the code come a topic and a key (PBKDF2-HMAC-SHA256, slow on
+  purpose: CODE_KDF_ITERATIONS). The host listens on the topic through the
+  signalling brokers (p2p_signal.c). A player who types the code asks
+  there (ASK: a nonce), and the host answers with its invite, sealed with
+  the key, with the nonce (INVITE); the asker opens it and joins as an
+  invite link would.
+- The brokers, and anyone who watches them, see the topic, but cannot tell
+  the code from it, or open the answer, short of working the slow
+  derivation out for codes until one fits; a code is guessed at one in 2^40
+  of them. An asker who has the code has the invite, as one given the link
+  has: it joins as anyone invited does.
+
+A build without this (another of the same network version) has no codes,
+and its players join with the link (which the host still logs and copies).
+*/
+
+#include "platform.h"
+#include "posix.h"
+#include "p2p_internal.h"
+
+#include <stdio.h>
+#include <string.h>
+
+enum
+{
+	CODE_SYMBOLS = 8,
+	CODE_KDF_ITERATIONS = 20000,
+	CODE_NONCE_SIZE = 8,
+	CODE_INVITE_SIZE = P2P_KEY_HASH_SIZE + P2P_TOKEN_SIZE,
+	CODE_MESSAGE_VERSION = 1,
+	/* milliseconds */
+	ASK_INTERVAL = 1000,
+	LOOK_TIMEOUT = 20000,
+	/* the host's answers: this many at once, and one more each this often */
+	MAXIMUM_ANSWERS = 8,
+	ANSWER_INTERVAL = 250,
+};
+
+enum
+{
+	_code_message_ask = 'Q',
+	_code_message_invite = 'I',
+};
+
+/* Crockford's base 32: no I, L, O or U */
+static const char code_alphabet[] = "0123456789ABCDEFGHJKMNPQRSTVWXYZ";
+
+static struct
+{
+	/* hosting: the code, its topic and key, and the invite it stands for */
+	int hosting;
+	char host_code[CODE_SYMBOLS + 1];
+	char host_topic[P2P_CODE_TOPIC_SIZE];
+	unsigned char host_key[P2P_SHA256_SIZE];
+	unsigned char invite[CODE_INVITE_SIZE];
+	int answers_left;
+	unsigned long answers_time;
+
+	/* looking a code up */
+	int status;
+	char look_topic[P2P_CODE_TOPIC_SIZE];
+	unsigned char look_key[P2P_SHA256_SIZE];
+	unsigned char look_nonce[CODE_NONCE_SIZE];
+	unsigned long look_started_time;
+	unsigned long asked_time;
+	int asked;
+} code;
+
+static int code_elapsed(unsigned long since, unsigned long time)
+{
+	return (unsigned int)(p2p_now() - since) >= (unsigned int)time;
+}
+
+/* the code's symbols from what was typed: letters and digits, read as
+Crockford reads them (O as 0, I and L as 1), the rest (dashes, spaces)
+left out; 0 unless they are exactly a code's */
+static int code_normalize(const char *text, char *symbols)
+{
+	int count = 0;
+
+	for (; *text; text++)
+	{
+		char character = *text;
+
+		if (character >= 'a' && character <= 'z')
+			character = (char)(character - 'a' + 'A');
+		if (character == 'O')
+			character = '0';
+		else if (character == 'I' || character == 'L')
+			character = '1';
+		if (!strchr(code_alphabet, character) || !character)
+		{
+			if (character == '-' || character == ' ' || character == '\t' || character == '\r' ||
+				character == '\n')
+			{
+				continue;
+			}
+			return 0;
+		}
+		if (count == CODE_SYMBOLS)
+			return 0;
+		symbols[count++] = character;
+	}
+	symbols[count] = 0;
+	return count == CODE_SYMBOLS;
+}
+
+/* the topic and key of a code (PBKDF2-HMAC-SHA256, one block) */
+static void code_derive(const char *symbols, char *topic, unsigned char *key)
+{
+	static const char salt[] = "halo-ce-vr join code 1";
+	unsigned char block[sizeof(salt) - 1 + 4];
+	unsigned char u[P2P_SHA256_SIZE];
+	unsigned char derived[P2P_SHA256_SIZE];
+	unsigned char digest[P2P_SHA256_SIZE];
+	char hex[2 * P2P_SHA256_SIZE + 1];
+	int iteration;
+	int index;
+
+	memcpy(block, salt, sizeof(salt) - 1);
+	block[sizeof(salt) - 1] = 0;
+	block[sizeof(salt)] = 0;
+	block[sizeof(salt) + 1] = 0;
+	block[sizeof(salt) + 2] = 1;
+	p2p_hmac_sha256((const unsigned char *)symbols, CODE_SYMBOLS, block, sizeof(block), u);
+	memcpy(derived, u, sizeof(derived));
+	for (iteration = 1; iteration < CODE_KDF_ITERATIONS; iteration++)
+	{
+		p2p_hmac_sha256((const unsigned char *)symbols, CODE_SYMBOLS, u, sizeof(u), u);
+		for (index = 0; index < P2P_SHA256_SIZE; index++)
+			derived[index] ^= u[index];
+	}
+	p2p_hmac_sha256(derived, sizeof(derived), "topic", 5, digest);
+	p2p_hex(digest, 16, hex);
+	snprintf(topic, P2P_CODE_TOPIC_SIZE, "hcvr/1/%s", hex);
+	p2p_hmac_sha256(derived, sizeof(derived), "seal", 4, key);
+}
+
+/* ---------- p2p.c's side (under p2p_lock) */
+
+void p2p_code_host(const unsigned char *invite)
+{
+	unsigned char random[CODE_SYMBOLS];
+	int index;
+
+	posix_random_bytes(random, sizeof(random));
+	for (index = 0; index < CODE_SYMBOLS; index++)
+		code.host_code[index] = code_alphabet[random[index] & 31];
+	code.host_code[CODE_SYMBOLS] = 0;
+	memcpy(code.invite, invite, CODE_INVITE_SIZE);
+	code_derive(code.host_code, code.host_topic, code.host_key);
+	code.answers_left = MAXIMUM_ANSWERS;
+	code.answers_time = p2p_now();
+	code.hosting = 1;
+	platform_log("Internet play: join code %.4s-%.4s", code.host_code, code.host_code + 4);
+	p2p_signal_sync_topics();
+}
+
+void p2p_code_stop_hosting(void)
+{
+	code.hosting = 0;
+	code.host_code[0] = 0;
+	p2p_signal_sync_topics();
+}
+
+int p2p_code_hosted(char *text, int size)
+{
+	if (!code.hosting || size < CODE_SYMBOLS + 2)
+		return 0;
+	snprintf(text, (size_t)size, "%.4s-%.4s", code.host_code, code.host_code + 4);
+	return 1;
+}
+
+int p2p_code_look_up(const char *typed)
+{
+	char symbols[CODE_SYMBOLS + 1];
+
+	if (!code_normalize(typed, symbols))
+	{
+		code.status = P2P_CODE_INVALID;
+		return 0;
+	}
+	if (code.hosting && !strcmp(symbols, code.host_code))
+	{
+		code.status = P2P_CODE_OWN;
+		return 0;
+	}
+	code_derive(symbols, code.look_topic, code.look_key);
+	posix_random_bytes(code.look_nonce, sizeof(code.look_nonce));
+	code.look_started_time = p2p_now();
+	code.asked = 0;
+	code.status = P2P_CODE_LOOKING;
+	p2p_signal_sync_topics();
+	return 1;
+}
+
+int p2p_code_status(void)
+{
+	return code.status;
+}
+
+void p2p_code_clear_status(void)
+{
+	if (code.status != P2P_CODE_LOOKING)
+		code.status = P2P_CODE_IDLE;
+}
+
+/* ---------- p2p_signal.c's side (under p2p_lock) */
+
+void p2p_code_topics(const char **host_topic, const char **look_topic)
+{
+	*host_topic = code.hosting ? code.host_topic : "";
+	*look_topic = code.status == P2P_CODE_LOOKING ? code.look_topic : "";
+}
+
+static void code_answer(const unsigned char *nonce)
+{
+	unsigned char message[2 + CODE_NONCE_SIZE + CODE_INVITE_SIZE];
+	unsigned char sealed[2 + sizeof(message) + P2P_SEAL_OVERHEAD];
+	int sealed_size;
+
+	/* (anyone watching the brokers can ask, as often as they like) */
+	while (code.answers_left < MAXIMUM_ANSWERS && code_elapsed(code.answers_time, ANSWER_INTERVAL))
+	{
+		code.answers_left++;
+		code.answers_time += ANSWER_INTERVAL;
+	}
+	if (code.answers_left == MAXIMUM_ANSWERS)
+		code.answers_time = p2p_now();
+	if (code.answers_left <= 0)
+		return;
+	code.answers_left--;
+	message[0] = _code_message_invite;
+	message[1] = CODE_MESSAGE_VERSION;
+	memcpy(message + 2, nonce, CODE_NONCE_SIZE);
+	memcpy(message + 2 + CODE_NONCE_SIZE, code.invite, CODE_INVITE_SIZE);
+	sealed[0] = _code_message_invite;
+	sealed[1] = CODE_MESSAGE_VERSION;
+	sealed_size = p2p_seal(code.host_key, message, sizeof(message), sealed + 2);
+	p2p_signal_publish(code.host_topic, sealed, 2 + sealed_size);
+}
+
+static void code_invite_received(const unsigned char *payload, int size)
+{
+	unsigned char message[2 + CODE_NONCE_SIZE + CODE_INVITE_SIZE + 16];
+	int message_size;
+	char hex[2 * CODE_INVITE_SIZE + 1];
+	char link[P2P_LINK_SIZE];
+
+	if (size > (int)sizeof(message) + P2P_SEAL_OVERHEAD)
+		return;
+	message_size = p2p_open(code.look_key, payload, size, message);
+	if (message_size != 2 + CODE_NONCE_SIZE + CODE_INVITE_SIZE || message[0] != _code_message_invite ||
+		message[1] != CODE_MESSAGE_VERSION || !p2p_equal(message + 2, code.look_nonce, CODE_NONCE_SIZE))
+	{
+		return;
+	}
+	code.status = P2P_CODE_FOUND;
+	p2p_signal_sync_topics();
+	p2p_hex(message + 2 + CODE_NONCE_SIZE, CODE_INVITE_SIZE, hex);
+	snprintf(link, sizeof(link), "halo://join/%s", hex);
+	platform_log("Internet play: the join code's host answered");
+	p2p_invite_received(link);
+}
+
+int p2p_code_received(const char *topic, const unsigned char *payload, int size)
+{
+	if (size < 2 || payload[1] != CODE_MESSAGE_VERSION)
+		return 0;
+	if (code.hosting && !strcmp(topic, code.host_topic))
+	{
+		if (payload[0] == _code_message_ask && size == 2 + CODE_NONCE_SIZE)
+			code_answer(payload + 2);
+		return 1;
+	}
+	if (code.status == P2P_CODE_LOOKING && !strcmp(topic, code.look_topic))
+	{
+		if (payload[0] == _code_message_invite)
+			code_invite_received(payload + 2, size - 2);
+		return 1;
+	}
+	return 0;
+}
+
+void p2p_code_update(void)
+{
+	unsigned char message[2 + CODE_NONCE_SIZE];
+
+	if (code.status != P2P_CODE_LOOKING)
+		return;
+	p2p_signal_start();
+	if (code_elapsed(code.look_started_time, LOOK_TIMEOUT))
+	{
+		code.status = P2P_CODE_NOT_FOUND;
+		p2p_signal_sync_topics();
+		platform_log("Internet play: no game answered the join code");
+		return;
+	}
+	if (!p2p_signal_connected() || (code.asked && !code_elapsed(code.asked_time, ASK_INTERVAL)))
+		return;
+	message[0] = _code_message_ask;
+	message[1] = CODE_MESSAGE_VERSION;
+	memcpy(message + 2, code.look_nonce, CODE_NONCE_SIZE);
+	p2p_signal_publish(code.look_topic, message, sizeof(message));
+	code.asked = 1;
+	code.asked_time = p2p_now();
+}

port/linux/src/p2p_internal.h

@@ -107,6 +107,52 @@ void p2p_signal_join(const unsigned char *host_hash, const unsigned char *token)
 void p2p_signal_stop_joining(void);
 /* whether any broker is connected */
 int p2p_signal_connected(void);
+/* (for p2p_code.c) the topics every broker listens on, as they are now; and
+a message to a topic through every broker */
+void p2p_signal_sync_topics(void);
+void p2p_signal_publish(const char *topic, const unsigned char *payload, int size);
+/* the same, kept by the brokers for whoever listens later (empty: no
+longer) */
+void p2p_signal_publish_retained(const char *topic, const unsigned char *payload, int size);
+
+/* ---------- p2p_code.c: join codes (under p2p_lock) */
+
+enum
+{
+	P2P_CODE_TOPIC_SIZE = 7 + 32 + 1,
+};
+
+/* hosting: a new code for the invite (its key hash and token), and none */
+void p2p_code_host(const unsigned char *invite);
+void p2p_code_stop_hosting(void);
+/* the code hosted, as XXXX-XXXX; 0 if none */
+int p2p_code_hosted(char *text, int size);
+/* starts looking up a typed code (0: not a code, or this machine's own;
+p2p_code_status says which) */
+int p2p_code_look_up(const char *typed);
+int p2p_code_status(void);
+/* forgets a finished look up's result */
+void p2p_code_clear_status(void);
+/* (p2p_signal.c) the topics to listen on (empty: none); a message on a
+topic, nonzero if it was a code's; and each pass of the p2p thread */
+void p2p_code_topics(const char **host_topic, const char **look_topic);
+int p2p_code_received(const char *topic, const unsigned char *payload, int size);
+void p2p_code_update(void);
+
+/* ---------- p2p_list.c: public games (under p2p_lock) */
+
+/* hosting: whether the game is listed, and what it is */
+void p2p_list_set_public(int public_game);
+int p2p_list_public(void);
+void p2p_list_set_description(const char *name, const char *map, const char *mode, int players,
+	int maximum_players);
+/* the games listed lately; asking keeps this machine listening a while */
+int p2p_list_games(struct p2p_public_game *games, int maximum);
+/* (p2p_signal.c) the topic to listen on (empty: none); a message on one
+(nonzero if it was a listing's); and each pass, whether hosting */
+const char *p2p_list_topic(void);
+int p2p_list_received(const char *topic, const unsigned char *payload, int size);
+void p2p_list_update(int hosting);
 
 /* ---------- p2p_crypto.c */
 

port/linux/src/p2p_list.c

@@ -0,0 +1,335 @@
+/*
+P2P_LIST.C
+
+Public games (the VR port's): a host may list its game for anyone, who
+finds it in a list of online games and joins it by its join code
+(p2p_code.c), without a server of this project's.
+
+- A public game's host announces it through the signalling brokers
+  (p2p_signal.c) every ANNOUNCE_INTERVAL, retained, on a topic of its own
+  under hcvr/1/g<network version>/: its name, map, game type, players, its
+  join code, and the time. Retained, a machine that starts listening gets
+  every game's latest at once. A host that stops (it closes its game, or
+  makes it private) clears its topic; one that quits without that leaves
+  its last announcement, which listeners drop once it is older than
+  STALE_SECONDS (by the machines' clocks).
+- A machine that shows the list listens on the topics of its network
+  version (a wildcard), and keeps the games heard of lately.
+- An announcement carries no address: a machine reaches a public game's
+  host only by its code, as anyone given the code does. Anyone can announce
+  anything, so what is shown is checked to be printable and in bounds, and
+  a game that is not what it says is only a code that does not answer.
+*/
+
+#include "platform.h"
+#include "posix.h"
+#include "port_config.h"
+#include "p2p_internal.h"
+#include "halo_port_limits.h"
+
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+
+enum
+{
+	ANNOUNCEMENT_VERSION = 1,
+	/* milliseconds */
+	ANNOUNCE_INTERVAL = 10000,
+	/* a listener's interest lapses this long after the menu last asked */
+	WATCH_TIME = 3000,
+	STALE_SECONDS = 45,
+	MAXIMUM_LISTED_GAMES = 32,
+};
+
+/* what goes to the brokers (byte for byte) */
+struct announcement
+{
+	char magic[4];
+	unsigned char version;
+	unsigned char players;
+	unsigned char maximum_players;
+	unsigned char flags;
+	unsigned char time[8];
+	char code[8];
+	char name[P2P_PUBLIC_NAME_SIZE];
+	char map[P2P_PUBLIC_MAP_SIZE];
+	char mode[P2P_PUBLIC_MODE_SIZE];
+};
+
+struct listed_game
+{
+	int used;
+	char topic[P2P_CODE_TOPIC_SIZE];
+	unsigned long heard_time;
+	long long announced_time;
+	struct p2p_public_game game;
+};
+
+static struct
+{
+	/* hosting (whether public: network.public_game, until Y changes it) */
+	int initialized;
+	int public_game;
+	char topic[P2P_CODE_TOPIC_SIZE];
+	int announced;
+	unsigned long announced_time;
+	char name[P2P_PUBLIC_NAME_SIZE];
+	char map[P2P_PUBLIC_MAP_SIZE];
+	char mode[P2P_PUBLIC_MODE_SIZE];
+	int players;
+	int maximum_players;
+
+	/* listening */
+	unsigned long watched_time;
+	int watching;
+	char watch_topic[P2P_CODE_TOPIC_SIZE];
+	struct listed_game games[MAXIMUM_LISTED_GAMES];
+} list;
+
+static int list_elapsed(unsigned long since, unsigned long time)
+{
+	return (unsigned int)(p2p_now() - since) >= (unsigned int)time;
+}
+
+/* text as shown: printable ASCII only, ended */
+static void list_text(char *destination, int size, const char *source, int source_size)
+{
+	int index;
+
+	for (index = 0; index < size - 1 && index < source_size && source[index]; index++)
+		destination[index] = source[index] >= 32 && source[index] < 127 ? source[index] : '?';
+	destination[index] = 0;
+}
+
+static long long list_time_now(void)
+{
+	return (long long)time(NULL);
+}
+
+static void list_topics_make(void)
+{
+	if (!list.topic[0])
+	{
+		unsigned char random[8];
+		char hex[17];
+
+		posix_random_bytes(random, sizeof(random));
+		p2p_hex(random, sizeof(random), hex);
+		snprintf(list.topic, sizeof(list.topic), "hcvr/1/g%d/%s", HALO_PORT_NETWORK_VERSION, hex);
+	}
+	if (!list.watch_topic[0])
+		snprintf(list.watch_topic, sizeof(list.watch_topic), "hcvr/1/g%d/+", HALO_PORT_NETWORK_VERSION);
+}
+
+static void list_announce(void)
+{
+	struct announcement announcement;
+	char code[16];
+	long long now = list_time_now();
+	int index;
+
+	if (!p2p_code_hosted(code, sizeof(code)))
+		return;
+	memset(&announcement, 0, sizeof(announcement));
+	memcpy(announcement.magic, "HCVR", 4);
+	announcement.version = ANNOUNCEMENT_VERSION;
+	announcement.players = (unsigned char)(list.players < 0 ? 0 : list.players > 255 ? 255 : list.players);
+	announcement.maximum_players =
+		(unsigned char)(list.maximum_players < 0 ? 0 : list.maximum_players > 255 ? 255 : list.maximum_players);
+	for (index = 0; index < 8; index++)
+		announcement.time[index] = (unsigned char)(now >> (8 * index));
+	/* (the code without its dash) */
+	memcpy(announcement.code, code, 4);
+	memcpy(announcement.code + 4, code + 5, 4);
+	memcpy(announcement.name, list.name, sizeof(announcement.name));
+	memcpy(announcement.map, list.map, sizeof(announcement.map));
+	memcpy(announcement.mode, list.mode, sizeof(announcement.mode));
+	p2p_signal_publish_retained(list.topic, (const unsigned char *)&announcement, sizeof(announcement));
+	if (!list.announced)
+		platform_log("Internet play: the game is listed as public (%s, %s, %s)", list.name, list.map, list.mode);
+	list.announced = 1;
+	list.announced_time = p2p_now();
+}
+
+static void list_withdraw(void)
+{
+	if (!list.announced)
+		return;
+	p2p_signal_publish_retained(list.topic, NULL, 0);
+	platform_log("Internet play: the game is no longer listed as public");
+	list.announced = 0;
+}
+
+/* ---------- p2p.c's side (under p2p_lock) */
+
+void p2p_list_set_public(int public_game)
+{
+	if (public_game == list.public_game)
+		return;
+	list.public_game = public_game;
+	list_topics_make();
+	if (!public_game)
+		list_withdraw();
+	else
+		list.announced_time = p2p_now() - ANNOUNCE_INTERVAL;
+}
+
+int p2p_list_public(void)
+{
+	return list.public_game;
+}
+
+void p2p_list_set_description(const char *name, const char *map, const char *mode, int players,
+	int maximum_players)
+{
+	int changed = strncmp(list.name, name, sizeof(list.name) - 1) || strncmp(list.map, map, sizeof(list.map) - 1) ||
+		strncmp(list.mode, mode, sizeof(list.mode) - 1) || players != list.players ||
+		maximum_players != list.maximum_players;
+
+	list_text(list.name, sizeof(list.name), name, P2P_PUBLIC_NAME_SIZE);
+	list_text(list.map, sizeof(list.map), map, P2P_PUBLIC_MAP_SIZE);
+	list_text(list.mode, sizeof(list.mode), mode, P2P_PUBLIC_MODE_SIZE);
+	list.players = players;
+	list.maximum_players = maximum_players;
+	/* (a change goes out soon, not at the next interval) */
+	if (changed && list.announced && list_elapsed(list.announced_time, 1000))
+		list.announced_time = p2p_now() - ANNOUNCE_INTERVAL;
+}
+
+int p2p_list_games(struct p2p_public_game *games, int maximum)
+{
+	int count = 0;
+	int index;
+
+	list.watched_time = p2p_now();
+	list.watching = 1;
+	for (index = 0; index < MAXIMUM_LISTED_GAMES && count < maximum; index++)
+	{
+		if (list.games[index].used)
+			games[count++] = list.games[index].game;
+	}
+	return count;
+}
+
+/* ---------- p2p_signal.c's side (under p2p_lock) */
+
+const char *p2p_list_topic(void)
+{
+	return list.watching ? list.watch_topic : "";
+}
+
+int p2p_list_received(const char *topic, const unsigned char *payload, int size)
+{
+	struct announcement announcement;
+	struct listed_game *slot = NULL;
+	long long announced = 0;
+	char code[16];
+	int index;
+
+	if (!list.watch_topic[0] || strncmp(topic, list.watch_topic, strlen(list.watch_topic) - 1))
+		return 0;
+	/* (this machine's own, as the broker echoes it) */
+	if (!strcmp(topic, list.topic))
+		return 1;
+	for (index = 0; index < MAXIMUM_LISTED_GAMES; index++)
+	{
+		if (list.games[index].used && !strcmp(list.games[index].topic, topic))
+			slot = &list.games[index];
+	}
+	if (size != (int)sizeof(announcement))
+	{
+		/* (empty: withdrawn) */
+		if (slot && size == 0)
+			slot->used = 0;
+		return 1;
+	}
+	memcpy(&announcement, payload, sizeof(announcement));
+	if (memcmp(announcement.magic, "HCVR", 4) || announcement.version != ANNOUNCEMENT_VERSION ||
+		!announcement.maximum_players || announcement.players > announcement.maximum_players)
+	{
+		return 1;
+	}
+	for (index = 0; index < 8; index++)
+		announced |= (long long)announcement.time[index] << (8 * index);
+	if (announced < list_time_now() - STALE_SECONDS || announced > list_time_now() + STALE_SECONDS)
+	{
+		if (slot)
+			slot->used = 0;
+		return 1;
+	}
+	snprintf(code, sizeof(code), "%.4s-%.4s", announcement.code, announcement.code + 4);
+	for (index = 0; code[index]; index++)
+	{
+		if (index != 4 && !((code[index] >= '0' && code[index] <= '9') || (code[index] >= 'A' && code[index] <= 'Z')))
+			return 1;
+	}
+	if (!slot)
+	{
+		int oldest = -1;
+
+		for (index = 0; index < MAXIMUM_LISTED_GAMES && !slot; index++)
+		{
+			if (!list.games[index].used)
+				slot = &list.games[index];
+			else if (oldest < 0 || list.games[index].announced_time < list.games[oldest].announced_time)
+				oldest = index;
+		}
+		if (!slot)
+			slot = &list.games[oldest];
+		memset(slot, 0, sizeof(*slot));
+		snprintf(slot->topic, sizeof(slot->topic), "%s", topic);
+	}
+	slot->used = 1;
+	slot->heard_time = p2p_now();
+	slot->announced_time = announced;
+	list_text(slot->game.name, sizeof(slot->game.name), announcement.name, sizeof(announcement.name));
+	list_text(slot->game.map, sizeof(slot->game.map), announcement.map, sizeof(announcement.map));
+	list_text(slot->game.mode, sizeof(slot->game.mode), announcement.mode, sizeof(announcement.mode));
+	snprintf(slot->game.code, sizeof(slot->game.code), "%s", code);
+	slot->game.players = announcement.players;
+	slot->game.maximum_players = announcement.maximum_players;
+	return 1;
+}
+
+void p2p_list_update(int hosting)
+{
+	int index;
+
+	if (!list.initialized)
+	{
+		list.initialized = 1;
+		if (!list.public_game)
+			list.public_game = config_boolean("network.public_game");
+	}
+	list_topics_make();
+	/* hosting a public game: announced every so often; withdrawn when it
+	is not */
+	if (hosting && list.public_game)
+	{
+		p2p_signal_start();
+		if (p2p_signal_connected() && list_elapsed(list.announced_time, ANNOUNCE_INTERVAL))
+			list_announce();
+	}
+	else if (list.announced)
+	{
+		list_withdraw();
+	}
+	/* listening while the menu asks */
+	if (list.watching && list_elapsed(list.watched_time, WATCH_TIME))
+	{
+		list.watching = 0;
+		memset(list.games, 0, sizeof(list.games));
+		p2p_signal_sync_topics();
+	}
+	else if (list.watching)
+	{
+		p2p_signal_start();
+		p2p_signal_sync_topics();
+	}
+	for (index = 0; index < MAXIMUM_LISTED_GAMES; index++)
+	{
+		if (list.games[index].used && list.games[index].announced_time < list_time_now() - STALE_SECONDS)
+			list.games[index].used = 0;
+	}
+}

port/linux/src/p2p_signal.c

@@ -82,6 +82,8 @@ enum
 	one is not forgotten while its host nonce lasts: USED_REQUEST_TIME) */
 	MAXIMUM_USED_REQUESTS = 1024,
 	TOPIC_SIZE = 7 + 32 + 1,
+	/* (p2p_code.c's are as long) */
+	TOPIC_SIZE_CHECK = 1 / (TOPIC_SIZE == P2P_CODE_TOPIC_SIZE),
 	NONCE_SIZE = 8,
 	/* an ACCEPT's or a proven JOIN's tag: the first half of an HMAC-SHA256 */
 	TAG_SIZE = 16,
@@ -152,6 +154,11 @@ struct broker
 	/* the topics it has been asked for */
 	char host_topic[TOPIC_SIZE];
 	char join_topic[TOPIC_SIZE];
+	/* (join codes' topics: p2p_code.c) */
+	char code_host_topic[TOPIC_SIZE];
+	char code_look_topic[TOPIC_SIZE];
+	/* (public games': p2p_list.c) */
+	char list_topic[TOPIC_SIZE];
 	unsigned char input[BUFFER_SIZE];
 	int input_size;
 	unsigned char output[BUFFER_SIZE];
@@ -321,6 +328,9 @@ static void broker_close(struct broker *broker, int failed)
 	broker->output_size = 0;
 	broker->host_topic[0] = 0;
 	broker->join_topic[0] = 0;
+	broker->code_host_topic[0] = 0;
+	broker->code_look_topic[0] = 0;
+	broker->list_topic[0] = 0;
 	if (failed)
 		broker->failures++;
 }
@@ -410,17 +420,22 @@ static void broker_publish(struct broker *broker, const char *topic, const unsig
 /* the topics a ready broker should be subscribed to */
 static void broker_sync_topics(struct broker *broker)
 {
-	const char *wanted[2];
-	char *had[2];
+	const char *wanted[5];
+	char *had[5];
 	int index;
 
 	if (broker->state != _broker_ready)
 		return;
 	wanted[0] = signalling.hosting ? signalling.host_topic : "";
 	wanted[1] = signalling.joining ? signalling.join_topic : "";
+	p2p_code_topics(&wanted[2], &wanted[3]);
+	wanted[4] = p2p_list_topic();
 	had[0] = broker->host_topic;
 	had[1] = broker->join_topic;
-	for (index = 0; index < 2; index++)
+	had[2] = broker->code_host_topic;
+	had[3] = broker->code_look_topic;
+	had[4] = broker->list_topic;
+	for (index = 0; index < 5; index++)
 	{
 		if (!strcmp(wanted[index], had[index]))
 			continue;
@@ -939,6 +954,8 @@ static void publish_received(struct broker *broker, const char *topic, const uns
 
 	if (size > MAXIMUM_MESSAGE_SIZE + P2P_SEAL_OVERHEAD)
 		return;
+	if (p2p_code_received(topic, payload, size) || p2p_list_received(topic, payload, size))
+		return;
 	if (signalling.hosting && !strcmp(topic, signalling.host_topic))
 	{
 		message_size = p2p_open(signalling.host_key, payload, size, message);
@@ -1190,6 +1207,8 @@ void p2p_signal_update(const int *read, int read_count, const int *write, int wr
 	}
 	if (signalling.joining && elapsed(signalling.join_sent_time, JOIN_INTERVAL))
 		send_join();
+	p2p_code_update();
+	p2p_list_update(signalling.hosting);
 }
 
 int p2p_signal_connected(void)
@@ -1212,6 +1231,39 @@ static void sync_all_topics(void)
 		broker_sync_topics(&signalling.brokers[index]);
 }
 
+void p2p_signal_sync_topics(void)
+{
+	sync_all_topics();
+}
+
+void p2p_signal_publish(const char *topic, const unsigned char *payload, int size)
+{
+	if (size <= MAXIMUM_MESSAGE_SIZE + P2P_SEAL_OVERHEAD)
+		publish_everywhere(topic, payload, size);
+}
+
+void p2p_signal_publish_retained(const char *topic, const unsigned char *payload, int size)
+{
+	unsigned char body[2 + TOPIC_SIZE + MAXIMUM_MESSAGE_SIZE];
+	int index;
+
+	if (size > MAXIMUM_MESSAGE_SIZE)
+		return;
+	for (index = 0; index < signalling.broker_count; index++)
+	{
+		struct broker *broker = &signalling.brokers[index];
+		int body_size;
+
+		if (broker->state != _broker_ready)
+			continue;
+		body_size = put_string(body, topic);
+		if (size)
+			memcpy(body + body_size, payload, (size_t)size);
+		/* (PUBLISH, at most once, retained: an empty one clears it) */
+		broker_send(broker, 0x31, body, body_size + size);
+	}
+}
+
 void p2p_signal_host(const unsigned char *token)
 {
 	if (!signalling.has_nonce_key)

port/linux/src/port_config.c

@@ -275,6 +275,9 @@ static const struct config_setting config_settings[] =
 		"clipboard) that lets whoever has it join over the internet; opening a\n"
 		"link (or copying one before switching to the game) joins. Only people\n"
 		"with the invite can join. Off keeps system link to the local network." },
+	{ "network.public_game", _config_boolean, "false", "HALO_NET_PUBLIC_GAME", _environment_value, _platform_all,
+		"Host games as public: listed for anyone among the online games (the\n"
+		"system link screen's X), as Y in a hosted game's lobby makes them." },
 	{ "network.join_from_clipboard", _config_boolean, "true", "HALO_NET_JOIN_FROM_CLIPBOARD", _environment_value,
 		_platform_all,
 		"Join the game of an invite link found on the clipboard when the game\n"
@@ -301,6 +304,12 @@ static const struct config_setting config_settings[] =
 		"The Discord application internet play invites go through while the\n"
 		"Discord desktop client runs; empty for none." },
 
+	{ "bots.count", _config_integer, "0", "HALO_BOTS_COUNT", _environment_value, _platform_android,
+		"Bots in the multiplayer games this machine hosts (0 to 15; 0: none):\n"
+		"players it drives itself, which every machine sees as players. Set in\n"
+		"the lobby's host options (Y)." },
+	{ "bots.skill", _config_integer, "1", "HALO_BOTS_SKILL", _environment_value, _platform_android,
+		"How well the bots play: 0 easy, 1 normal, 2 hard." },
 	{ "update.auto", _config_boolean, "true", "HALO_UPDATE_AUTO", _environment_value, _platform_all,
 		"Look for a new version when the game starts, and offer to update to it;\n"
 		"false never looks (the game's \"Do not ask again\" writes false here)." },
@@ -950,7 +959,9 @@ static int config_line_section(const char *line, const char *end, char *section,
 
 /* sets a boolean setting, for now and in config.toml: its line there is
 changed (or added), the rest of the file kept as it is */
-int config_write_boolean(const char *name, int value)
+/* a boolean's or an integer's new value, kept and written into the file
+(the line of its key replaced, else added to its section) */
+static int config_write_value(const char *name, int type, long value)
 {
 	const char *dot = strchr(name, '.');
 	long index = config_setting_index(name);
@@ -961,15 +972,24 @@ int config_write_boolean(const char *name, int value)
 	const char *line;
 	int written = 0, in_section = 0, succeeded;
 
-	if (index < 0 || config_settings[index].type != _config_boolean || !dot || (size_t)(dot - name) >= sizeof(section))
+	if (index < 0 || config_settings[index].type != type || !dot || (size_t)(dot - name) >= sizeof(section))
 		return 0;
 	/* (the file read first, as the other settings are) */
-	config_boolean(name);
+	if (type == _config_boolean)
+		config_boolean(name);
+	else
+		config_integer(name);
 	pthread_mutex_lock(&config_lock);
-	config_values[index].boolean = value != 0;
+	if (type == _config_boolean)
+		config_values[index].boolean = value != 0;
+	else
+		config_values[index].integer = value;
 	snprintf(section, sizeof(section), "%.*s", (int)(dot - name), name);
 	snprintf(key, sizeof(key), "%s", dot + 1);
-	snprintf(line_text, sizeof(line_text), "%s = %s\n", key, value ? "true" : "false");
+	if (type == _config_boolean)
+		snprintf(line_text, sizeof(line_text), "%s = %s\n", key, value ? "true" : "false");
+	else
+		snprintf(line_text, sizeof(line_text), "%s = %ld\n", key, value);
 	snprintf(wanted, sizeof(wanted), "%s", section);
 	config_path(path, sizeof(path));
 	text = config_read_file(path, &size);
@@ -1026,6 +1046,16 @@ int config_write_boolean(const char *name, int value)
 	return succeeded;
 }
 
+int config_write_boolean(const char *name, int value)
+{
+	return config_write_value(name, _config_boolean, value != 0);
+}
+
+int config_write_integer(const char *name, long value)
+{
+	return config_write_value(name, _config_integer, value);
+}
+
 /* ---------- public code */
 
 int config_boolean(const char *name)

port/linux/src/port_config.h

@@ -21,5 +21,6 @@ const char *config_string(const char *name);
 /* sets a boolean setting, and writes it into config.toml (only its line
 changes); 1 on success */
 int config_write_boolean(const char *name, int value);
+int config_write_integer(const char *name, long value);
 
 #endif

port/linux/src/sdl_platform.c

@@ -614,18 +614,56 @@ static BOOL platform_text_has_invite_link(const char *text)
 	return FALSE;
 }
 
+/* the last clipboard text looked at, kept beside the settings from run to
+run (the VR port's): a run's own invite, still on the clipboard when the
+game starts again, is not joined then (its host, the run before, is gone,
+and the attempt held up a join for a minute and a half) */
+static void platform_clipboard_seen(char *seen, int size, BOOL save)
+{
+	char path[512];
+	FILE *file;
+
+	snprintf(path, sizeof(path), "%s/clipboard_seen.txt", platform_data_root());
+	if (save)
+	{
+		file = fopen(path, "wb");
+		if (file)
+		{
+			fputs(seen, file);
+			fclose(file);
+		}
+		return;
+	}
+	file = fopen(path, "rb");
+	if (!file)
+		return;
+	{
+		size_t length = fread(seen, 1, (size_t)size - 1, file);
+
+		seen[length] = 0;
+	}
+	fclose(file);
+}
+
 /* puts a new invite on the clipboard, and joins one found there when the
 game comes to the front */
 static void platform_invite_clipboard(BOOL look)
 {
 	/* the last clipboard text looked at, so each invite is joined once */
 	static char seen[256];
+	static BOOL seen_loaded;
 	const char *invite = p2p_take_clipboard_text();
 
+	if (!seen_loaded)
+	{
+		seen_loaded = TRUE;
+		platform_clipboard_seen(seen, sizeof(seen), FALSE);
+	}
 	if (invite)
 	{
 		SDL_SetClipboardText(invite);
 		snprintf(seen, sizeof(seen), "%s", invite);
+		platform_clipboard_seen(seen, sizeof(seen), TRUE);
 		platform_log("Internet play: the invite link is on the clipboard");
 #ifdef HALO_ANDROID
 		SDL_ShowAndroidToast("Hosting: the invite link is on the clipboard", 1, -1, 0, 0);
@@ -638,6 +676,7 @@ static void platform_invite_clipboard(BOOL look)
 		if (text && strcmp(text, seen) && strlen(text) < sizeof(seen))
 		{
 			snprintf(seen, sizeof(seen), "%s", text);
+			platform_clipboard_seen(seen, sizeof(seen), TRUE);
 			/* (a link, not a bare code: 64 hex digits alone are as often a
 			checksum copied for something else) */
 			if (platform_text_has_invite_link(text) && p2p_join_invite(text))

source/interface/event_manager.c

@@ -42,7 +42,13 @@ enum
 	_event_type_right_stick,
 	_event_type_button,
 
+#ifdef HALO_ANDROID
+	/* (the VR port's: a headset's controllers' thumbsticks are pushed as
+	far less readily than a gamepad's) */
+	STICK_EVENT_THRESHOLD = 22937,
+#else
 	STICK_EVENT_THRESHOLD = 29490,
+#endif
 	STICK_EVENT_REPEAT_MILLISECONDS = 250
 };
 
@@ -71,6 +77,24 @@ typedef char verify_event_manager_state_size[
 typedef char verify_event_manager_globals_size[
 	sizeof(struct event_manager_globals) == 0x168 ? 1 : -1];
 
+#ifdef HALO_ANDROID
+/* The VR port's: a stick held moves on once after a pause, then quickly,
+as menus do now (the Xbox's moved on every quarter second, which in a
+headset, with the keyboard's letters to cross, is slow going). */
+enum
+{
+	STICK_REPEAT_FIRST_MILLISECONDS = 350,
+	STICK_REPEAT_MILLISECONDS = 90,
+};
+
+static short stick_repeats[NUMBER_OF_GAMEPAD_STICKS][MAXIMUM_GAMEPADS];
+
+#define STICK_REPEAT_INTERVAL(stick, controller_index) \
+	(stick_repeats[stick][controller_index] ? STICK_REPEAT_MILLISECONDS : STICK_REPEAT_FIRST_MILLISECONDS)
+#else
+#define STICK_REPEAT_INTERVAL(stick, controller_index) STICK_EVENT_REPEAT_MILLISECONDS
+#endif
+
 /* ---------- prototypes */
 
 static void queue_event(
@@ -83,6 +107,30 @@ struct event_manager_globals event_manager_globals = { 0 };
 
 /* ---------- public code */
 
+#ifdef HALO_ANDROID
+/* an event the stick posts: a fresh push (it was within the threshold on
+that axis) starts the count of repeats again */
+static void stick_note_event(
+	short stick,
+	short controller_index,
+	long x,
+	long y,
+	unsigned long time)
+{
+	boolean fresh =
+		(ABS(x) >= STICK_EVENT_THRESHOLD &&
+			ABS(event_manager_globals.previous_stick_axes[stick][0][controller_index]) < STICK_EVENT_THRESHOLD) ||
+		(ABS(y) >= STICK_EVENT_THRESHOLD &&
+			ABS(event_manager_globals.previous_stick_axes[stick][1][controller_index]) < STICK_EVENT_THRESHOLD);
+
+	(void)time;
+	if (fresh)
+		stick_repeats[stick][controller_index] = 0;
+	else if (stick_repeats[stick][controller_index] < SHORT_MAX)
+		stick_repeats[stick][controller_index]++;
+}
+
+#endif
 void event_manager_initialize(
 	void)
 {
@@ -209,12 +257,16 @@ static void queue_event(
 				ABS(event_manager_globals.previous_stick_axes[_gamepad_stick_left][0][controller_index]) < STICK_EVENT_THRESHOLD) ||
 			(ABS(y) >= STICK_EVENT_THRESHOLD &&
 				ABS(event_manager_globals.previous_stick_axes[_gamepad_stick_left][1][controller_index]) < STICK_EVENT_THRESHOLD) ||
-			time - event_manager_globals.stick_event_times[_gamepad_stick_left][controller_index] >= STICK_EVENT_REPEAT_MILLISECONDS))
+			time - event_manager_globals.stick_event_times[_gamepad_stick_left][controller_index] >=
+				STICK_REPEAT_INTERVAL(_gamepad_stick_left, controller_index)))
 		{
 			post = FALSE;
 		}
 		else
 		{
+#ifdef HALO_ANDROID
+			stick_note_event(_gamepad_stick_left, controller_index, x, y, time);
+#endif
 			event_manager_globals.stick_event_times[_gamepad_stick_left][controller_index] = time;
 			post = TRUE;
 
@@ -260,12 +312,16 @@ static void queue_event(
 				ABS(event_manager_globals.previous_stick_axes[_gamepad_stick_right][0][controller_index]) < STICK_EVENT_THRESHOLD) ||
 			(ABS(y) >= STICK_EVENT_THRESHOLD &&
 				ABS(event_manager_globals.previous_stick_axes[_gamepad_stick_right][1][controller_index]) < STICK_EVENT_THRESHOLD) ||
-			time - event_manager_globals.stick_event_times[_gamepad_stick_right][controller_index] >= STICK_EVENT_REPEAT_MILLISECONDS))
+			time - event_manager_globals.stick_event_times[_gamepad_stick_right][controller_index] >=
+				STICK_REPEAT_INTERVAL(_gamepad_stick_right, controller_index)))
 		{
 			post = FALSE;
 		}
 		else
 		{
+#ifdef HALO_ANDROID
+			stick_note_event(_gamepad_stick_right, controller_index, x, y, time);
+#endif
 			event_manager_globals.stick_event_times[_gamepad_stick_right][controller_index] = time;
 			post = TRUE;
 

source/interface/ui_widget.c

@@ -5591,6 +5591,543 @@ static boolean ui_mouse_menus_active(
 }
 
 #ifdef HALO_ANDROID
+/* ---------- join codes (the VR port's)
+
+Internet play's join codes (port/linux/src/p2p_code.c) and public games
+(p2p_list.c): the host's lobby shows its game's code, and Y there lists the
+game for anyone or not; on the screen of games to join, X opens a panel of
+the public games and a way to type a code in, either of which then joins as
+an invite link does (the game shows up in the list once its host is
+reached). */
+
+int p2p_join_code(char *text, int size);
+int p2p_join_with_code(char const *typed);
+int p2p_join_code_status(void);
+void p2p_join_code_clear_status(void);
+int p2p_join_state(void);
+
+enum
+{
+	/* p2p.h's */
+	_join_code_idle,
+	_join_code_looking,
+	_join_code_found,
+	_join_code_not_found,
+	_join_code_invalid,
+	_join_code_own,
+	_join_code_offline,
+};
+
+enum
+{
+	/* p2p.h's */
+	_join_state_none,
+	_join_state_reaching,
+	_join_state_connected,
+	_join_state_no_answer,
+	_join_state_blocked,
+	_join_state_lost,
+};
+
+struct ui_public_game
+{
+	/* p2p.h's struct p2p_public_game */
+	char name[16];
+	char map[32];
+	char mode[24];
+	char code[12];
+	int players;
+	int maximum_players;
+};
+
+void p2p_set_public_game(int public_game);
+int p2p_public_game(void);
+int p2p_public_games(struct ui_public_game *games, int maximum);
+long config_integer(char const *name);
+int config_write_integer(char const *name, long value);
+
+enum
+{
+	MAXIMUM_SHOWN_PUBLIC_GAMES = 32,
+	/* the online games panel's rows: "enter a code" and the games */
+	ONLINE_PANEL_ROWS = 11,
+};
+
+static struct
+{
+	boolean keyboard_launched;
+	wchar_t typed[12];
+	/* the panel of online games, over the screen of games to join */
+	boolean panel_open;
+	short selection;
+	short scroll;
+	short game_count;
+	struct ui_public_game games[MAXIMUM_SHOWN_PUBLIC_GAMES];
+	/* the host options panel, over a hosted game's lobby */
+	boolean host_panel_open;
+	short host_selection;
+} ui_join_code_globals;
+
+enum
+{
+	/* the host options: public, bots, their skill */
+	HOST_PANEL_ROWS = 3,
+	MAXIMUM_BOTS_SHOWN = 15,
+};
+
+/* the multiplayer maps' names, as the menus show them */
+static char const *ui_join_code_map_name(
+	char const *map)
+{
+	static char const *const names[][2] = {
+		{ "beavercreek", "Battle Creek" }, { "bloodgulch", "Blood Gulch" }, { "boardingaction", "Boarding Action" },
+		{ "carousel", "Derelict" }, { "chillout", "Chill Out" }, { "damnation", "Damnation" },
+		{ "dangercanyon", "Danger Canyon" }, { "deathisland", "Death Island" }, { "gephyrophobia", "Gephyrophobia" },
+		{ "hangemhigh", "Hang 'Em High" }, { "icefields", "Ice Fields" }, { "infinity", "Infinity" },
+		{ "longest", "Longest" }, { "prisoner", "Prisoner" }, { "putput", "Chiron TL-34" },
+		{ "ratrace", "Rat Race" }, { "sidewinder", "Sidewinder" }, { "timberland", "Timberland" },
+		{ "wizard", "Wizard" },
+	};
+	short index;
+
+	for (index = 0; index < (short)NUMBEROF(names); index++)
+	{
+		if (!strcmp(map, names[index][0]))
+			return names[index][1];
+	}
+	return map;
+}
+
+static boolean ui_join_code_screen_active(
+	char const *name)
+{
+	return widget_globals.active_widgets[0] && widget_globals.active_widgets[0]->name &&
+		strcmp(widget_globals.active_widgets[0]->name, name) == 0;
+}
+
+static void ui_join_code_launch_keyboard(
+	void)
+{
+	ui_join_code_globals.typed[0] = 0;
+	virtual_keyboard_set_caption(L"Enter the join code of an online game");
+	if (!virtual_keyboard_launch(ui_join_code_globals.typed, sizeof(ui_join_code_globals.typed), 8))
+	{
+		virtual_keyboard_set_caption(NULL);
+		return;
+	}
+	p2p_join_code_clear_status();
+	ui_join_code_globals.keyboard_launched = TRUE;
+}
+
+/* the panel's input: the stick or the pad's arrows choose a row, A takes
+it, B closes it */
+static void ui_join_code_panel_event(
+	struct event_record const *event)
+{
+	short rows = (short)(ui_join_code_globals.game_count + 1);
+	short move = 0;
+
+	if (event->type == _event_type_left_stick)
+	{
+		if (event->data.stick.y == SHORT_MAX)
+			move = -1;
+		else if (event->data.stick.y == SHORT_MIN)
+			move = 1;
+	}
+	else if (event->type == _event_type_button && event->data.button.value == 1)
+	{
+		switch (event->data.button.index)
+		{
+		case _gamepad_binary_button_dpad_up: move = -1; break;
+		case _gamepad_binary_button_dpad_down: move = 1; break;
+		case _gamepad_analog_button_b:
+		case _gamepad_binary_button_back:
+			ui_join_code_globals.panel_open = FALSE;
+			break;
+		case _gamepad_analog_button_x:
+			ui_join_code_globals.panel_open = FALSE;
+			ui_join_code_launch_keyboard();
+			break;
+		case _gamepad_analog_button_a:
+		case _gamepad_binary_button_start:
+			ui_join_code_globals.panel_open = FALSE;
+			if (ui_join_code_globals.selection == 0 ||
+				ui_join_code_globals.selection > ui_join_code_globals.game_count)
+			{
+				ui_join_code_launch_keyboard();
+			}
+			else
+			{
+				p2p_join_code_clear_status();
+				p2p_join_with_code(ui_join_code_globals.games[ui_join_code_globals.selection - 1].code);
+			}
+			break;
+		}
+	}
+	if (move)
+	{
+		ui_join_code_globals.selection = (short)PIN(ui_join_code_globals.selection + move, 0, rows - 1);
+		if (ui_join_code_globals.selection < ui_join_code_globals.scroll)
+			ui_join_code_globals.scroll = ui_join_code_globals.selection;
+		else if (ui_join_code_globals.selection >= ui_join_code_globals.scroll + ONLINE_PANEL_ROWS)
+			ui_join_code_globals.scroll = (short)(ui_join_code_globals.selection - ONLINE_PANEL_ROWS + 1);
+	}
+}
+
+/* the host options panel's input: the stick or the pad's arrows up and
+down choose a row, left and right (or A) change it, B or Y closes it */
+static void ui_join_code_host_panel_event(
+	struct event_record const *event)
+{
+	short move = 0;
+	short change = 0;
+
+	if (event->type == _event_type_left_stick)
+	{
+		if (event->data.stick.y == SHORT_MAX)
+			move = -1;
+		else if (event->data.stick.y == SHORT_MIN)
+			move = 1;
+		else if (event->data.stick.x == SHORT_MAX)
+			change = 1;
+		else if (event->data.stick.x == SHORT_MIN)
+			change = -1;
+	}
+	else if (event->type == _event_type_button && event->data.button.value == 1)
+	{
+		switch (event->data.button.index)
+		{
+		case _gamepad_binary_button_dpad_up: move = -1; break;
+		case _gamepad_binary_button_dpad_down: move = 1; break;
+		case _gamepad_binary_button_dpad_right:
+		case _gamepad_analog_button_a:
+			change = 1;
+			break;
+		case _gamepad_binary_button_dpad_left: change = -1; break;
+		case _gamepad_analog_button_b:
+		case _gamepad_analog_button_y:
+		case _gamepad_binary_button_back:
+			ui_join_code_globals.host_panel_open = FALSE;
+			break;
+		}
+	}
+	if (move)
+		ui_join_code_globals.host_selection = (short)PIN(ui_join_code_globals.host_selection + move, 0, HOST_PANEL_ROWS - 1);
+	if (!change)
+		return;
+	switch (ui_join_code_globals.host_selection)
+	{
+	case 0:
+		p2p_set_public_game(!p2p_public_game());
+		break;
+	case 1:
+	{
+		/* (A goes round: past the most, none) */
+		long count = config_integer("bots.count") + change;
+
+		if (count > MAXIMUM_BOTS_SHOWN)
+			count = event->type == _event_type_button && event->data.button.index == _gamepad_analog_button_a ? 0 :
+				MAXIMUM_BOTS_SHOWN;
+		config_write_integer("bots.count", PIN(count, 0, MAXIMUM_BOTS_SHOWN));
+		break;
+	}
+	case 2:
+	{
+		long skill = config_integer("bots.skill") + change;
+
+		if (skill > 2)
+			skill = event->type == _event_type_button && event->data.button.index == _gamepad_analog_button_a ? 0 : 2;
+		config_write_integer("bots.skill", PIN(skill, 0, 2));
+		break;
+	}
+	}
+}
+
+/* X on the screen of games to join: the panel of online games (and in it,
+everything); Y in a hosted game's lobby: the host options (public, bots).
+TRUE: the event is taken. */
+static boolean ui_join_code_take_event(
+	struct widget_instance *widget,
+	struct event_record const *event)
+{
+	if (widget != widget_globals.active_widgets[0])
+		return FALSE;
+	if (ui_join_code_globals.host_panel_open)
+	{
+		if (!ui_join_code_screen_active("connected_pregame_screen") || !global_network_game_server_get())
+		{
+			ui_join_code_globals.host_panel_open = FALSE;
+			return FALSE;
+		}
+		ui_join_code_host_panel_event(event);
+		return TRUE;
+	}
+	if (ui_join_code_globals.panel_open)
+	{
+		if (!ui_join_code_screen_active("server_list_screen"))
+		{
+			ui_join_code_globals.panel_open = FALSE;
+			return FALSE;
+		}
+		ui_join_code_panel_event(event);
+		return TRUE;
+	}
+	if (event->type != _event_type_button || event->data.button.value != 1)
+		return FALSE;
+	if (event->data.button.index == _gamepad_analog_button_x && ui_join_code_screen_active("server_list_screen"))
+	{
+		ui_join_code_globals.panel_open = TRUE;
+		ui_join_code_globals.selection = 0;
+		ui_join_code_globals.scroll = 0;
+		return TRUE;
+	}
+	if (event->data.button.index == _gamepad_analog_button_y &&
+		ui_join_code_screen_active("connected_pregame_screen") && global_network_game_server_get())
+	{
+		ui_join_code_globals.host_panel_open = TRUE;
+		ui_join_code_globals.host_selection = 0;
+		return TRUE;
+	}
+	return FALSE;
+}
+
+/* the keyboard closed: the code typed, looked up */
+static void ui_join_code_update(
+	void)
+{
+	char text[sizeof(ui_join_code_globals.typed) / sizeof(wchar_t)];
+	short index;
+
+	if (!ui_join_code_globals.keyboard_launched || virtual_keyboard_active())
+		return;
+	ui_join_code_globals.keyboard_launched = FALSE;
+	virtual_keyboard_set_caption(NULL);
+	if (!virtual_keyboard_last_exit_saved_text())
+		return;
+	for (index = 0; index < (short)(NUMBEROF(text) - 1) && ui_join_code_globals.typed[index]; index++)
+	{
+		wchar_t character = ui_join_code_globals.typed[index];
+
+		text[index] = character < 128 ? (char)character : '?';
+	}
+	text[index] = 0;
+	p2p_join_with_code(text);
+}
+
+/* text in bounds, left, right or centred (0, 1, 2) */
+static void ui_join_code_draw_text(
+	short x0,
+	short x1,
+	short y0,
+	char const *text,
+	boolean icons,
+	short justification,
+	real_argb_color const *color)
+{
+	rectangle2d bounds;
+	wchar_t wide[96];
+	short index;
+	long font_index = tag_loaded(FONT_GROUP_TAG, "ui\\small_ui");
+
+	if (font_index == NONE)
+		return;
+	for (index = 0; index < (short)(NUMBEROF(wide) - 1) && text[index]; index++)
+		wide[index] = (wchar_t)(unsigned char)text[index];
+	wide[index] = 0;
+	bounds.y0 = y0;
+	bounds.y1 = (short)(y0 + 20);
+	bounds.x0 = x0;
+	bounds.x1 = x1;
+	draw_string_set_draw_mode(font_index, NONE, justification, 0, color);
+	if (icons)
+		draw_string_and_hack_in_icons(&bounds, &bounds, NULL, 0, wide, FALSE);
+	else
+		rasterizer_draw_unicode_string(&bounds, &bounds, NULL, 0, wide);
+}
+
+static void ui_join_code_draw_line(
+	short y0,
+	char const *text,
+	boolean icons,
+	boolean centered)
+{
+	real_argb_color color = { 1.0f, 0.85f, 0.85f, 0.85f };
+
+	ui_join_code_draw_text((short)(centered ? 0 : 48), (short)(centered ? 640 : 600), y0, text, icons,
+		(short)(centered ? 2 : 0), &color);
+}
+
+static void ui_join_code_draw_quad(
+	short x0,
+	short y0,
+	short x1,
+	short y1,
+	unsigned long color)
+{
+	rectangle2d bounds;
+
+	bounds.x0 = x0;
+	bounds.y0 = y0;
+	bounds.x1 = x1;
+	bounds.y1 = y1;
+	draw_quad(&bounds, color);
+}
+
+/* the panel of online games: "enter a code", then the public games */
+static void ui_join_code_render_panel(
+	void)
+{
+	real_argb_color title_color = { 1.0f, 0.55f, 0.75f, 1.0f };
+	real_argb_color text_color = { 1.0f, 0.85f, 0.85f, 0.85f };
+	real_argb_color dim_color = { 1.0f, 0.6f, 0.6f, 0.6f };
+	char line[64];
+	short row;
+
+	ui_join_code_globals.game_count =
+		(short)p2p_public_games(ui_join_code_globals.games, MAXIMUM_SHOWN_PUBLIC_GAMES);
+	ui_join_code_globals.selection =
+		(short)PIN(ui_join_code_globals.selection, 0, ui_join_code_globals.game_count);
+	ui_join_code_draw_quad(40, 72, 600, 410, 0xF0050A18);
+	ui_join_code_draw_quad(40, 72, 600, 74, 0xFF3A6EA5);
+	ui_join_code_draw_quad(40, 408, 600, 410, 0xFF3A6EA5);
+	snprintf(line, sizeof(line), "ONLINE GAMES (%d public)", (int)ui_join_code_globals.game_count);
+	ui_join_code_draw_text(56, 584, 80, line, FALSE, 0, &title_color);
+	ui_join_code_draw_text(56, 216, 104, "Name", FALSE, 0, &dim_color);
+	ui_join_code_draw_text(216, 376, 104, "Map", FALSE, 0, &dim_color);
+	ui_join_code_draw_text(376, 516, 104, "Game", FALSE, 0, &dim_color);
+	ui_join_code_draw_text(516, 584, 104, "Players", FALSE, 1, &dim_color);
+	for (row = 0; row < ONLINE_PANEL_ROWS; row++)
+	{
+		short index = (short)(ui_join_code_globals.scroll + row);
+		short y = (short)(128 + row * 22);
+
+		if (index > ui_join_code_globals.game_count)
+			break;
+		if (index == ui_join_code_globals.selection)
+			ui_join_code_draw_quad(48, y, 592, (short)(y + 21), 0x803A6EA5);
+		if (index == 0)
+		{
+			ui_join_code_draw_text(56, 584, (short)(y + 1), "Enter a join code...", FALSE, 0, &text_color);
+		}
+		else
+		{
+			struct ui_public_game const *game = &ui_join_code_globals.games[index - 1];
+
+			ui_join_code_draw_text(56, 212, (short)(y + 1), game->name, FALSE, 0, &text_color);
+			ui_join_code_draw_text(216, 372, (short)(y + 1), ui_join_code_map_name(game->map), FALSE, 0,
+				&text_color);
+			ui_join_code_draw_text(376, 512, (short)(y + 1), game->mode, FALSE, 0, &text_color);
+			snprintf(line, sizeof(line), "%d/%d", game->players, game->maximum_players);
+			ui_join_code_draw_text(516, 584, (short)(y + 1), line, FALSE, 1, &text_color);
+		}
+	}
+	if (!ui_join_code_globals.game_count)
+		ui_join_code_draw_text(56, 584, 152, "No public games right now", FALSE, 0, &dim_color);
+	ui_join_code_draw_text(56, 584, 384, "%a-button Join   %x-button Enter a code   %b-button Back", TRUE, 0,
+		&text_color);
+}
+
+/* over the screens, as they are drawn */
+static void ui_join_code_render(
+	void)
+{
+	char code[16];
+
+	if (ui_join_code_screen_active("server_list_screen"))
+	{
+		char const *status = NULL;
+
+		if (ui_join_code_globals.panel_open)
+		{
+			ui_join_code_render_panel();
+			return;
+		}
+		ui_join_code_draw_line(372, "%x-button Online games: public ones, or join by a code", TRUE, FALSE);
+		switch (p2p_join_code_status())
+		{
+		case _join_code_looking: status = "Looking for the game of that code..."; break;
+		case _join_code_found: status = "Found it: the game shows up in the list once its host is reached"; break;
+		case _join_code_not_found: status = "No game answered that code"; break;
+		case _join_code_invalid: status = "That is not a join code (8 letters and digits)"; break;
+		case _join_code_own: status = "That is this game's own code"; break;
+		case _join_code_offline: status = "Online play is off (network.online in config.toml)"; break;
+		}
+		/* (the code found, or a link: how reaching its host goes) */
+		if (!status || p2p_join_code_status() == _join_code_found)
+		{
+			switch (p2p_join_state())
+			{
+			case _join_state_reaching: status = "Reaching the online game's host..."; break;
+			case _join_state_connected: status = "Connected: the online game is in the list above"; break;
+			case _join_state_no_answer: status = "The host did not answer: it may have stopped hosting"; break;
+			case _join_state_blocked: status = "Blocked by the routers: allow UPnP on yours or the host's"; break;
+			case _join_state_lost: status = "Lost the connection to the online game's host"; break;
+			}
+		}
+		if (status)
+			ui_join_code_draw_line(392, status, FALSE, FALSE);
+	}
+	else if (ui_join_code_screen_active("connected_pregame_screen") && global_network_game_server_get())
+	{
+		char line[128];
+		long bots = config_integer("bots.count");
+		char bots_text[24];
+
+		if (bots > 0)
+			snprintf(bots_text, sizeof(bots_text), "%ld bot%s", bots, bots == 1 ? "" : "s");
+		else
+			snprintf(bots_text, sizeof(bots_text), "no bots");
+		if (p2p_join_code(code, sizeof(code)))
+		{
+			snprintf(line, sizeof(line), "Online join code: %s      %%y-button Host options (%s, %s)", code,
+				p2p_public_game() ? "public" : "private", bots_text);
+		}
+		else
+		{
+			snprintf(line, sizeof(line), "%%y-button Host options (%s)", bots_text);
+		}
+		/* (under the buttons' key) */
+		ui_join_code_draw_line(448, line, TRUE, TRUE);
+		if (ui_join_code_globals.host_panel_open)
+		{
+			static char const *const skills[] = { "Easy", "Normal", "Hard" };
+			real_argb_color title_color = { 1.0f, 0.55f, 0.75f, 1.0f };
+			real_argb_color text_color = { 1.0f, 0.85f, 0.85f, 0.85f };
+			short row;
+
+			ui_join_code_draw_quad(140, 150, 500, 330, 0xF0050A18);
+			ui_join_code_draw_quad(140, 150, 500, 152, 0xFF3A6EA5);
+			ui_join_code_draw_quad(140, 328, 500, 330, 0xFF3A6EA5);
+			ui_join_code_draw_text(156, 484, 158, "HOST OPTIONS", FALSE, 0, &title_color);
+			for (row = 0; row < HOST_PANEL_ROWS; row++)
+			{
+				short y = (short)(190 + row * 30);
+
+				if (row == ui_join_code_globals.host_selection)
+					ui_join_code_draw_quad(148, (short)(y - 3), 492, (short)(y + 21), 0x803A6EA5);
+				switch (row)
+				{
+				case 0:
+					snprintf(line, sizeof(line), "Public game: %s", p2p_public_game() ? "Yes (listed online)" : "No");
+					break;
+				case 1:
+					snprintf(line, sizeof(line), "Bots: %s", bots > 0 ? bots_text : "None");
+					break;
+				default:
+				{
+					long skill = PIN(config_integer("bots.skill"), 0, 2);
+
+					snprintf(line, sizeof(line), "Bot skill: %s", skills[skill]);
+					break;
+				}
+				}
+				ui_join_code_draw_text(160, 484, y, line, FALSE, 0, &text_color);
+			}
+			ui_join_code_draw_text(156, 484, 300, "%a-button Change   %b-button Done", TRUE, 0, &text_color);
+		}
+	}
+}
+
 /* whether a menu is up (VR shows it on a screen in the room: render.c) */
 boolean ui_widgets_menus_active(
 	void)
@@ -6045,6 +6582,9 @@ void render_ui_widgets(
 				}
 			}
 		}
+#ifdef HALO_ANDROID
+		ui_join_code_render();
+#endif
 		if (widget_globals.fade_to_black >= 0.0f &&
 			widget_globals.fade_to_black <= 1.0f)
 		{
@@ -6987,6 +7527,9 @@ void process_ui_widgets(
 
 		return;
 	}
+#ifdef HALO_ANDROID
+	ui_join_code_update();
+#endif
 	if (attract_mode_should_start())
 	{
 		attract_mode_start();
@@ -7088,6 +7631,10 @@ void process_ui_widgets(
 			{
 				do
 				{
+#ifdef HALO_ANDROID
+					if (ui_join_code_take_event(widget, &event))
+						continue;
+#endif
 					if (!pause_pressed)
 					{
 						widget_instance_process_one_event_recursive(

source/interface/virtual_keyboard.c

@@ -96,6 +96,18 @@ symbols in this file:
 #include "text/text_group.h"
 #include "text/unicode.h"
 
+#ifdef HALO_ANDROID
+/* the VR port's: a caption of its own instead of the string list's, for a
+keyboard it launches (ui_widget.c's join codes); NULL for the list's */
+static wchar_t const *virtual_keyboard_caption_override;
+
+void virtual_keyboard_set_caption(
+	wchar_t const *caption)
+{
+	virtual_keyboard_caption_override = caption;
+}
+#endif
+
 /* ---------- constants */
 
 enum
@@ -671,6 +683,10 @@ static void virtual_keyboard_render_internal(
 		wchar_t *caption = unicode_string_list_get_string(
 			virtual_keyboard_globals.keyboard->special_key_labels_string_list_tag.index,
 			virtual_keyboard_globals.caption_index);
+#ifdef HALO_ANDROID
+		if (virtual_keyboard_caption_override)
+			caption = (wchar_t *)virtual_keyboard_caption_override;
+#endif
 
 		bounds.y0 = 78;
 		bounds.x0 = 114;

source/interface/virtual_keyboard.h

@@ -38,6 +38,10 @@ void virtual_keyboard_process(
 	void);
 void virtual_keyboard_render(
 	void);
+#ifdef HALO_ANDROID
+void virtual_keyboard_set_caption(
+	wchar_t const *caption);
+#endif
 
 /* ---------- globals */
 

source/networking/network_server_manager.c

@@ -475,6 +475,10 @@ symbols in this file:
 
 /* port: internet play's Discord presence (port/linux/src/p2p.c) */
 void p2p_set_game_player_counts(int count, int maximum);
+#ifdef HALO_ANDROID
+void p2p_set_game_description(char const *name, char const *map, char const *mode, int players,
+	int maximum_players);
+#endif
 
 /* ---------- constants */
 
@@ -692,6 +696,12 @@ typedef char network_game_server_countdown_state_offset_assert[
 	offsetof(struct network_game_server, countdown_state) ==
 		8 + HALO_PORT_NETWORK_GAME_SIZE + MAXIMUM_NETWORK_MACHINE_COUNT * 0x10 + 0xC ? 1 : -1];
 
+#ifdef HALO_ANDROID
+/* bots' machines (below: the VR port's bots) */
+static boolean network_game_server_bot_machines[MAXIMUM_NETWORK_MACHINE_COUNT];
+static short network_game_server_bot_machine_count(struct network_game_server *server);
+#endif
+
 /* ---------- prototypes */
 
 void countdown_timer_increment(
@@ -1308,6 +1318,42 @@ boolean network_game_server_idle(
 
 	/* (what Discord shows of a game hosted for internet play) */
 	p2p_set_game_player_counts(server->game.player_count, server->game.maximum_players);
+#ifdef HALO_ANDROID
+	/* (and what a public game's listing says: port/linux/src/p2p_list.c) */
+	{
+		char name[16], map[32], mode[24];
+		char const *map_name = server->game.map.name;
+		char const *separator;
+		short index;
+
+		for (index = 0; index < (short)(NUMBEROF(name) - 1) && server->game.name[index]; index++)
+			name[index] = server->game.name[index] < 128 ? (char)server->game.name[index] : '?';
+		name[index] = 0;
+		/* (the scenario's name, the last of its path) */
+		while ((separator = strpbrk(map_name, "\\/")) != NULL)
+			map_name = separator + 1;
+		csstrncpy(map, map_name, sizeof(map) - 1);
+		map[sizeof(map) - 1] = 0;
+		for (index = 0; index < (short)(NUMBEROF(mode) - 1) && index < 12 &&
+			server->game.variant.human_readable_game_description[index]; index++)
+		{
+			wchar_t character = server->game.variant.human_readable_game_description[index];
+
+			mode[index] = character < 128 ? (char)character : '?';
+		}
+		mode[index] = 0;
+		/* (a game type without a name of its own: its kind's) */
+		if (!mode[0])
+		{
+			static char const *const kinds[] = { "", "CTF", "Slayer", "Oddball", "King of the Hill", "Race" };
+			long kind = server->game.variant.game_engine_index;
+
+			csstrncpy(mode, kind > 0 && kind < (long)NUMBEROF(kinds) ? kinds[kind] : "Custom", sizeof(mode) - 1);
+			mode[sizeof(mode) - 1] = 0;
+		}
+		p2p_set_game_description(name, map, mode, server->game.player_count, server->game.maximum_players);
+	}
+#endif
 
 	if (network_game_server_game_is_valid(server))
 	{
@@ -2855,6 +2901,10 @@ boolean server_has_enough_machines(
 		}
 	}
 
+#ifdef HALO_ANDROID
+	/* (bots' machines count: the VR port's) */
+	machine_count += network_game_server_bot_machine_count(server);
+#endif
 	has_enough_machines = machine_count >= minimum_machine_count;
 
 	return has_enough_machines;
@@ -3508,7 +3558,11 @@ void network_game_server_update_countdown(
 				else
 				{
 					if (network_game_should_accept_remote_connections() == FALSE ||
-						network_game_server_get_client_machine_count(server) > 1)
+						network_game_server_get_client_machine_count(server)
+#ifdef HALO_ANDROID
+							+ network_game_server_bot_machine_count(server)
+#endif
+							> 1)
 					{
 						unsigned long countdown;
 
@@ -3775,6 +3829,11 @@ static boolean network_game_server_add_new_client(
 	{
 		for (i = 0; i < MAXIMUM_NETWORK_MACHINE_COUNT; i++)
 		{
+#ifdef HALO_ANDROID
+			/* (not a bot machine's slot) */
+			if (network_game_server_bot_machines[i] && server->game.machines[i].machine_index == i)
+				continue;
+#endif
 			if (server->client_machines[i].machine_index == NONE)
 			{
 				struct transport_address client_address = { 0 };
@@ -4144,6 +4203,221 @@ static boolean network_game_server_have_all_machines_have_precached(
 	return all_machines_have_precached;
 }
 
+#ifdef HALO_ANDROID
+/* ---------- bots (the VR port's: port/linux/game/bots.c)
+
+Bots are the players of machines of the host's own that nothing connects
+to: from the top slot down, four players each (a machine's most). The host
+drives them (bots_tick); every other machine sees them as any other
+machine's players. A new connection never takes a bot's slot, and in the
+lobby they count as machines, so that a game of the host and bots starts. */
+
+long config_integer(char const *name);
+
+static void network_game_server_bot_copy_name(
+	wchar_t *destination,
+	wchar_t const *source,
+	short size)
+{
+	short index;
+
+	for (index = 0; index < size - 1 && source[index]; index++)
+		destination[index] = source[index];
+	destination[index] = 0;
+}
+
+boolean network_game_server_is_bot_machine(
+	long machine_index)
+{
+	struct network_game_server *server = global_network_game_server_get();
+
+	return server && VALID_INDEX(machine_index, MAXIMUM_NETWORK_MACHINE_COUNT) &&
+		network_game_server_bot_machines[machine_index] &&
+		server->game.machines[machine_index].machine_index == machine_index;
+}
+
+static short network_game_server_bot_machine_count(
+	struct network_game_server *server)
+{
+	short count = 0;
+	long machine_index;
+
+	for (machine_index = 0; machine_index < MAXIMUM_NETWORK_MACHINE_COUNT; machine_index++)
+	{
+		if (network_game_server_bot_machines[machine_index] &&
+			server->game.machines[machine_index].machine_index == machine_index &&
+			network_game_server_machine_has_players(server, (short)machine_index))
+		{
+			count++;
+		}
+	}
+	return count;
+}
+
+static short network_game_server_bot_count(
+	struct network_game_server *server,
+	struct network_player **last)
+{
+	short count = 0;
+	long player_index;
+
+	*last = NULL;
+	for (player_index = 0; player_index < MAXIMUM_NETWORK_PLAYER_COUNT; player_index++)
+	{
+		struct network_player *player = &server->game.players[player_index];
+
+		if (network_player_is_valid(player) && VALID_INDEX(player->machine_index, MAXIMUM_NETWORK_MACHINE_COUNT) &&
+			network_game_server_bot_machines[(long)player->machine_index])
+		{
+			count++;
+			*last = player;
+		}
+	}
+	return count;
+}
+
+static boolean network_game_server_add_bot(
+	struct network_game_server *server,
+	short number)
+{
+	struct network_player bot;
+	long machine_index;
+	short controller_index;
+
+	if (!network_game_has_free_player_slot(&server->game))
+		return FALSE;
+	/* (a bot machine with room, else a new one from the top) */
+	for (machine_index = MAXIMUM_NETWORK_MACHINE_COUNT - 1; machine_index >= 0; machine_index--)
+	{
+		if (network_game_server_bot_machines[machine_index] &&
+			server->game.machines[machine_index].machine_index == machine_index)
+		{
+			for (controller_index = 0; controller_index < MAXIMUM_LOCAL_PLAYERS; controller_index++)
+			{
+				long player_index;
+				boolean taken = FALSE;
+
+				for (player_index = 0; player_index < MAXIMUM_NETWORK_PLAYER_COUNT && !taken; player_index++)
+				{
+					struct network_player *player = &server->game.players[player_index];
+
+					taken = network_player_is_valid(player) && player->machine_index == machine_index &&
+						player->controller_index == controller_index;
+				}
+				if (!taken)
+					goto found;
+			}
+		}
+	}
+	for (machine_index = MAXIMUM_NETWORK_MACHINE_COUNT - 1; machine_index >= 0; machine_index--)
+	{
+		if (!server->client_machines[machine_index].connection &&
+			server->client_machines[machine_index].machine_index == NONE &&
+			server->game.machines[machine_index].machine_index == NONE)
+		{
+			struct network_machine machine;
+
+			csmemset(&machine, 0, sizeof(machine));
+			network_game_server_bot_copy_name(machine.name, L"Bots", NUMBEROF(machine.name));
+			machine.machine_index = (char)machine_index;
+			if (!network_game_add_machine(&server->game, &machine))
+				return FALSE;
+			network_game_server_bot_machines[machine_index] = TRUE;
+			controller_index = 0;
+			goto found;
+		}
+	}
+	return FALSE;
+
+found:
+	csmemset(&bot, 0, sizeof(bot));
+	{
+		wchar_t name[NETWORK_PLAYER_NAME_LENGTH];
+		short length = 0;
+		short digits = number < 10 ? 1 : number < 100 ? 2 : 3;
+		short digit;
+
+		network_game_server_bot_copy_name(name, L"Bot ", NUMBEROF(name));
+		while (name[length])
+			length++;
+		for (digit = digits - 1; digit >= 0 && length + digit < NETWORK_PLAYER_NAME_LENGTH - 1; digit--)
+		{
+			name[length + digit] = (wchar_t)(L'0' + number % 10);
+			number /= 10;
+		}
+		name[length + digits] = 0;
+		network_game_server_bot_copy_name(bot.name, name, NUMBEROF(bot.name));
+	}
+	bot.machine_index = (char)machine_index;
+	bot.controller_index = (char)controller_index;
+	bot.primary_color_index = NONE;
+	bot.icon_index = 0;
+	{
+		long player_count_by_team[NUMBER_OF_MULTIPLAYER_TEAMS] = { 0, 0 };
+		long player_index;
+
+		for (player_index = 0; player_index < MAXIMUM_NETWORK_PLAYER_COUNT; player_index++)
+		{
+			struct network_player *other_player = &server->game.players[player_index];
+
+			if (network_player_is_valid(other_player) && VALID_INDEX(other_player->team_index, NUMBER_OF_MULTIPLAYER_TEAMS))
+				player_count_by_team[other_player->team_index]++;
+		}
+		bot.team_index = player_count_by_team[1] < player_count_by_team[0] ? 1 : 0;
+	}
+	if (!player_name_is_unique(server, bot.name))
+		get_unique_random_name(server, &bot);
+	get_unique_random_color(server, &bot);
+	bot.player_list_index = NONE;
+	if (!network_game_add_player(&server->game, &bot))
+		return FALSE;
+	network_event("added a bot on machine %ld", machine_index);
+	return TRUE;
+}
+
+/* (the lobby) as many bots as bots.count asks for */
+static void network_game_server_update_bots(
+	struct network_game_server *server)
+{
+	long wanted = config_integer("bots.count");
+	struct network_player *last;
+	short count = network_game_server_bot_count(server, &last);
+	boolean changed = FALSE;
+	long machine_index;
+
+	/* (bot machines a new game no longer has) */
+	for (machine_index = 0; machine_index < MAXIMUM_NETWORK_MACHINE_COUNT; machine_index++)
+	{
+		if (network_game_server_bot_machines[machine_index] &&
+			server->game.machines[machine_index].machine_index != machine_index)
+		{
+			network_game_server_bot_machines[machine_index] = FALSE;
+		}
+	}
+	wanted = PIN(wanted, 0, 15);
+	while (count < wanted && network_game_server_add_bot(server, (short)(count + 1)))
+	{
+		count++;
+		changed = TRUE;
+	}
+	while (count > wanted && network_game_server_bot_count(server, &last) > 0 && last)
+	{
+		long bot_machine = last->machine_index;
+
+		network_game_remove_player(&server->game, last);
+		if (!network_game_server_machine_has_players(server, (short)bot_machine))
+		{
+			network_game_remove_machine(&server->game, &server->game.machines[bot_machine]);
+			network_game_server_bot_machines[bot_machine] = FALSE;
+		}
+		count--;
+		changed = TRUE;
+	}
+	if (changed)
+		network_game_server_send_game_data_pregame(server);
+}
+#endif
+
 static boolean network_game_server_idle_pregame_tasks(
 	struct network_game_server *server)
 {
@@ -4154,6 +4428,9 @@ static boolean network_game_server_idle_pregame_tasks(
 	{
 		long itr;
 
+#ifdef HALO_ANDROID
+		network_game_server_update_bots(server);
+#endif
 		/* send the lobby changes collected since the last settings update */
 		network_game_server_flush_game_data_pregame(server);