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Support private/public IP in Realm response + ORM update + DB migration #1489

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Support private/public IP in Realm response + ORM update + DB migration #1489

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6287b3a
Add public IP columns to RealmModels
Belnadifia Apr 27, 2025
13973fb
Update serve_realmlist and redirect_to_world
Belnadifia Apr 27, 2025
02d8b7a
Add public IPs columns to realmlist
Belnadifia Apr 27, 2025
3898900
Changing Default public IP
Belnadifia Apr 27, 2025
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2 changes: 2 additions & 0 deletions database/realm/RealmModels.py
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Original file line number Diff line number Diff line change
Expand Up @@ -341,7 +341,9 @@ class RealmList(Base):
realm_id = Column(INTEGER(11), autoincrement=True, nullable=False, primary_key=True)
realm_name = Column(String(255), nullable=False, server_default=text(""))
proxy_address = Column(String(15), nullable=False, server_default="0.0.0.0")
public_proxy_address = Column(String(15), nullable=False, server_default="0.0.0.0")
proxy_port = Column(INTEGER(11), nullable=False, server_default="9090")
realm_address = Column(String(15), nullable=False, server_default="0.0.0.0")
public_realm_address = Column(String(15), nullable=False, server_default="0.0.0.0")
realm_port = Column(INTEGER(11), nullable=False, server_default="9100")
online_player_count = Column(INTEGER(11), nullable=False, server_default="0")
9 changes: 9 additions & 0 deletions etc/databases/realm/updates/updates.sql
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Original file line number Diff line number Diff line change
Expand Up @@ -251,5 +251,14 @@ begin not atomic
insert into applied_updates values ('100120251');
end if;

-- 27/04/2025 1
if (select count(*) from applied_updates where id='270420251') = 0 then
ALTER TABLE realmlist
ADD COLUMN `public_realm_address` VARCHAR(255) DEFAULT '0.0.0.0' AFTER `realm_address`,
ADD COLUMN `public_proxy_address` VARCHAR(255) DEFAULT '0.0.0.0' AFTER `proxy_address`;

insert into applied_updates values ('270420251');
end if;

end $
delimiter ;
39 changes: 26 additions & 13 deletions game/realm/RealmManager.py
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
import os
import socket
import traceback
import ipaddress

from game.world.WorldSessionStateHandler import RealmDatabaseManager
from network.packet.PacketWriter import *
Expand All @@ -9,6 +10,11 @@
from utils.Logger import Logger
from utils.constants import EnvVars

def is_private_ip(ip):
try:
return ipaddress.ip_address(ip).is_private
except ValueError:
return False

REALMLIST = {realm.realm_id: realm for realm in RealmDatabaseManager.realm_get_list()}

Expand All @@ -18,20 +24,21 @@ class RealmManager:

@staticmethod
def serve_realmlist(sck):
client_ip = sck.getpeername()[0]
realmlist_bytes = pack('<B', len(REALMLIST))

for realm in REALMLIST.values():
is_realm_local = config.Server.Connection.Realm.local_realm_id == realm.realm_id

name_bytes = PacketWriter.string_to_bytes(realm.realm_name)
# Only check if the forward address needs to be overriden if this realm is hosted on this same machine.
# Docker on Windows hackfix.
# https://discord.com/channels/628574828038717470/653374433636909077/840314080073351238
if is_realm_local:
forward_address = os.getenv(EnvVars.EnvironmentalVariables.FORWARD_ADDRESS_OVERRIDE,
realm.proxy_address)
else:

if is_private_ip(client_ip):
forward_address = realm.proxy_address
Logger.debug(f'[{sck.getpeername()[0]}] Connection from {client_ip} -> Private')
else:
forward_address = realm.public_proxy_address
Logger.debug(f'[{sck.getpeername()[0]}] Connection from {client_ip} -> Public')


address_bytes = PacketWriter.string_to_bytes(f'{forward_address}:{realm.proxy_port}')
online_count = RealmDatabaseManager.realmlist_get_online_player_count(realm.realm_id)
Expand All @@ -43,27 +50,33 @@ def serve_realmlist(sck):
online_count
)

Logger.debug(f'[{sck.getpeername()[0]}] Sending realmlist...')
Logger.debug(f'[{sck.getpeername()[0]}] Sending realmlist... (sent {forward_address}:{realm.proxy_port})')
sck.sendall(realmlist_bytes)

@staticmethod
def redirect_to_world(sck):
forward_address = os.getenv(EnvVars.EnvironmentalVariables.FORWARD_ADDRESS_OVERRIDE,
config.Server.Connection.WorldServer.host)
client_ip = sck.getpeername()[0]
local_realm = REALMLIST[config.Server.Connection.Realm.local_realm_id]

if is_private_ip(client_ip):
forward_address = local_realm.realm_address
else:
forward_address = local_realm.public_realm_address


world_bytes = PacketWriter.string_to_bytes(f'{forward_address}:{config.Server.Connection.WorldServer.port}')
packet = pack(
f'<{len(world_bytes)}s',
world_bytes
)

Logger.debug(f'[{sck.getpeername()[0]}] Redirecting to world server...')
Logger.debug(f'[{client_ip}] Redirecting to world server... (sent {forward_address}:{config.Server.Connection.WorldServer.port})')
sck.sendall(packet)

@staticmethod
def start_realm(running, realm_server_ready):
local_realm = REALMLIST[config.Server.Connection.Realm.local_realm_id]
with SocketBuilder.build_socket(local_realm.realm_address, local_realm.realm_port, timeout=2) as server_socket:
with SocketBuilder.build_socket('0.0.0.0', local_realm.realm_port, timeout=2) as server_socket:
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@GrenderG GrenderG May 30, 2025

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Why bind to 0.0.0.0 here?

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@Belnadifia Belnadifia May 30, 2025

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When setting up a server socket, you might think to bind directly to a specific interface or IP address. However, in most modern deployments—especially in Kubernetes or cloud environments—binding to 0.0.0.0 is the correct and robust choice.

Why not bind to a specific IP?
Pods in Kubernetes have their own internal IPs (e.g., 10.x.x.x), which are only reachable from inside the cluster.

Externally, your service is typically accessed through a Load Balancer or NodePort with a different IP (e.g., 172.16.x.x).

Your application (or database, etc.) configuration might advertise the external (load balancer) IP, but your pod/container does not have that IP as a local interface!

If you bind your server to this external IP, the server won’t actually receive any connections, because that IP does not exist inside the pod.

Example scenario
Suppose:

Your pod’s internal IP is 10.0.0.1 (only reachable from within the cluster).

Your service is exposed externally at 172.16.0.54 (load balancer or worker node).

In your database or config, you have to advertise 172.16.0.54 as the address clients should use.

If you bind your socket to 172.16.0.54, your server will not listen on any actual interface inside the pod—because that IP does not exist inside the pod.

The correct solution: Bind to 0.0.0.0
Binding to 0.0.0.0 means “listen on all available interfaces and all incoming destination IPs”.
This ensures:

Your server can accept connections, no matter which network interface or cluster routing path is used.

Clients (inside or outside the cluster) can reach your service as long as the port is exposed.

It works for both internal and external clients, across NAT, service mesh, and Kubernetes routing.

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@GrenderG GrenderG May 30, 2025

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I understand that, but it shouldn't be hardcoded; listening on 0.0.0.0 might not be suitable for everyone, depending on their server setup. Also, since FORWARD_ADDRESS_OVERRIDE becomes obsolete with these changes, all references to it should be removed, including in the Docker setup script.

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@Belnadifia Belnadifia May 30, 2025

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If think listening on 0.0.0.0 is suitable for almost 90% of users ^•^
Having multiple NIC is mostly rare for common user (well, if we put asside WLAN)
Using 0.0.0.0 will accept any connection, no matter the server setup.
I understand it's shouldn't be hardcoded for specific case (most of the time, we use 0.0.0.0) , but then you should create a new ENV Variable and prosion it from conf file with 0.0.0.0 as default value.

And for FORWARD_ADDRESS_OVERRIDE, been a certain so I haven't the code in mind at the moment.

server_socket.listen()
real_binding = server_socket.getsockname()
# Make sure all characters have online = 0 on realm start.
Expand All @@ -90,7 +103,7 @@ def start_realm(running, realm_server_ready):
@staticmethod
def start_proxy(running, proxy_server_ready):
local_realm = REALMLIST[config.Server.Connection.Realm.local_realm_id]
with SocketBuilder.build_socket(local_realm.proxy_address, local_realm.proxy_port, timeout=2) as server_socket:
with SocketBuilder.build_socket('0.0.0.0', local_realm.proxy_port, timeout=2) as server_socket:
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@GrenderG GrenderG May 30, 2025

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Same here.

server_socket.listen()
real_binding = server_socket.getsockname()
Logger.success(f'Proxy server started, listening on {real_binding[0]}:{real_binding[1]}')
Expand Down