From 6adb2c98c3a10e563c344cad585674041b5eaa82 Mon Sep 17 00:00:00 2001
From: Denis Drakhnia <numas13@gmail.com>
Date: Sun, 28 Jan 2024 09:28:04 +0200
Subject: [PATCH] master: limit amount of servers with same ip

---
 master/config/main.toml     |  4 +++-
 master/src/config.rs        |  6 ++++++
 master/src/master_server.rs | 25 +++++++++++++++++++++----
 3 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/master/config/main.toml b/master/config/main.toml
index 899ce96..8d244b9 100644
--- a/master/config/main.toml
+++ b/master/config/main.toml
@@ -7,13 +7,15 @@ level = "info"
 [server]
 ip = "0.0.0.0"
 port = 27010
+# How many servers with the same ip can be registred
+max-servers-per-ip = 14
 
 [server.timeout]
 # Time in seconds while challenge is valid
 challenge = 10
 # Time in seconds while server is valid
 server = 300
-# TIme in seconds before next admin request is allowed after wrong password
+# Time in seconds before next admin request is allowed after wrong password
 admin = 10
 
 [client]
diff --git a/master/src/config.rs b/master/src/config.rs
index 79821eb..3d74ba7 100644
--- a/master/src/config.rs
+++ b/master/src/config.rs
@@ -20,6 +20,8 @@ pub const DEFAULT_CHALLENGE_TIMEOUT: u32 = 10;
 pub const DEFAULT_SERVER_TIMEOUT: u32 = 300;
 pub const DEFAULT_ADMIN_TIMEOUT: u32 = 10;
 
+pub const DEFAULT_MAX_SERVERS_PER_IP: u16 = 14;
+
 pub const DEFAULT_HASH_LEN: usize = admin::HASH_LEN;
 
 macro_rules! impl_helpers {
@@ -76,11 +78,14 @@ impl Default for LogConfig {
 
 #[derive(Deserialize, Debug)]
 #[serde(deny_unknown_fields)]
+#[serde(rename_all = "kebab-case")]
 pub struct ServerConfig {
     #[serde(default = "default_server_ip")]
     pub ip: IpAddr,
     #[serde(default = "default_u16::<DEFAULT_MASTER_SERVER_PORT>")]
     pub port: u16,
+    #[serde(default = "default_u16::<DEFAULT_MAX_SERVERS_PER_IP>")]
+    pub max_servers_per_ip: u16,
     #[serde(default)]
     pub timeout: TimeoutConfig,
 }
@@ -90,6 +95,7 @@ impl Default for ServerConfig {
         Self {
             ip: default_server_ip(),
             port: DEFAULT_MASTER_SERVER_PORT,
+            max_servers_per_ip: DEFAULT_MAX_SERVERS_PER_IP,
             timeout: Default::default(),
         }
     }
diff --git a/master/src/master_server.rs b/master/src/master_server.rs
index 67a9c36..dc01791 100644
--- a/master/src/master_server.rs
+++ b/master/src/master_server.rs
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 // SPDX-FileCopyrightText: 2023 Denis Drakhnia <numas13@gmail.com>
 
+use std::collections::hash_map;
 use std::io;
 use std::net::{Ipv4Addr, SocketAddr, SocketAddrV4, ToSocketAddrs, UdpSocket};
 use std::ops::Deref;
@@ -108,6 +109,7 @@ pub struct MasterServer {
     challenges_counter: Counter,
     servers: HashMap<SocketAddrV4, Entry<ServerInfo>>,
     servers_counter: Counter,
+    max_servers_per_ip: u16,
     rng: Rng,
 
     start_time: Instant,
@@ -180,6 +182,7 @@ impl MasterServer {
             challenges_counter: Counter::new(CHALLENGE_CLEANUP_MAX),
             servers: Default::default(),
             servers_counter: Counter::new(SERVER_CLEANUP_MAX),
+            max_servers_per_ip: cfg.server.max_servers_per_ip,
             rng: Rng::new(),
             timeout: cfg.server.timeout,
             clver: cfg.client.version,
@@ -492,11 +495,25 @@ impl MasterServer {
         }
     }
 
+    fn count_servers(&self, addr: &Ipv4Addr) -> u16 {
+        self.servers.keys().filter(|i| i.ip() == addr).count() as u16
+    }
+
     fn add_server(&mut self, addr: SocketAddrV4, server: ServerInfo) {
-        let entry = Entry::new(self.now(), server);
-        match self.servers.insert(addr, entry) {
-            Some(_) => trace!("{}: Updated GameServer", addr),
-            None => trace!("{}: New GameServer", addr),
+        let now = self.now();
+        match self.servers.entry(addr) {
+            hash_map::Entry::Occupied(mut e) => {
+                trace!("{}: Updated GameServer", addr);
+                e.insert(Entry::new(now, server));
+            }
+            hash_map::Entry::Vacant(_) => {
+                if self.count_servers(addr.ip()) >= self.max_servers_per_ip {
+                    trace!("{}: max servers per ip", addr);
+                    return;
+                }
+                trace!("{}: New GameServer", addr);
+                self.servers.insert(addr, Entry::new(now, server));
+            }
         }
     }