Add server-side anti-cheat evidence scoring

src/game/char.cpp

@@ -347,6 +347,9 @@ void CHARACTER::Initialize()
 	m_dwLastComboTime = 0;
 	m_bComboIndex = 0;
 	m_iComboHackCount = 0;
+	m_iAntiCheatScore = 0;
+	m_dwLastAntiCheatScoreTime = 0;
+	m_dwLastAntiCheatPersistTime = 0;
 	m_dwSkipComboAttackByTime = 0;
 
 	m_dwMountTime = 0;
@@ -7238,6 +7241,68 @@ void CHARACTER::ResetComboHackCount()
 	m_iComboHackCount = 0;
 }
 
+namespace
+{
+	constexpr int kAntiCheatMaxScore = 1000;
+	constexpr int kAntiCheatDisconnectScore = 100;
+	constexpr DWORD kAntiCheatDecayIntervalMs = 15000;
+	constexpr DWORD kAntiCheatPersistIntervalMs = 5000;
+}
+
+void CHARACTER::DecayAntiCheatScore(DWORD dwNow)
+{
+	if (0 == m_dwLastAntiCheatScoreTime)
+	{
+		m_dwLastAntiCheatScoreTime = dwNow;
+		return;
+	}
+
+	const DWORD dwElapsed = dwNow - m_dwLastAntiCheatScoreTime;
+	if (dwElapsed < kAntiCheatDecayIntervalMs)
+		return;
+
+	const int iDecaySteps = dwElapsed / kAntiCheatDecayIntervalMs;
+	m_iAntiCheatScore = MAX(0, m_iAntiCheatScore - iDecaySteps);
+	m_dwLastAntiCheatScoreTime += iDecaySteps * kAntiCheatDecayIntervalMs;
+}
+
+void CHARACTER::RecordAntiCheatViolation(const char* category, int score, const char* detail, bool forcePersist)
+{
+	const DWORD dwNow = get_dword_time();
+	DecayAntiCheatScore(dwNow);
+
+	if (score <= 0)
+		score = 1;
+
+	m_iAntiCheatScore = MIN(kAntiCheatMaxScore, m_iAntiCheatScore + score);
+
+	char szReason[512];
+	snprintf(szReason,
+		 sizeof(szReason),
+		 "ANTI_CHEAT[%s] score=%d map=%ld pos=(%ld,%ld) detail=%s",
+		 category ? category : "UNKNOWN",
+		 m_iAntiCheatScore,
+		 static_cast<long>(GetMapIndex()),
+		 static_cast<long>(GetX()),
+		 static_cast<long>(GetY()),
+		 detail ? detail : "-");
+
+	sys_log(0, "%s pid=%u name=%s", szReason, GetPlayerID(), GetName());
+
+	const bool shouldPersist = forcePersist || (GetDesc() && dwNow - m_dwLastAntiCheatPersistTime >= kAntiCheatPersistIntervalMs);
+	if (shouldPersist && GetDesc())
+	{
+		LogManager::instance().HackLog(szReason, this);
+		m_dwLastAntiCheatPersistTime = dwNow;
+	}
+
+	if (GetDesc() && m_iAntiCheatScore >= kAntiCheatDisconnectScore)
+	{
+		if (GetDesc()->DelayedDisconnect(number(3, 8)))
+			sys_log(0, "ANTI_CHEAT_DISCONNECT: %s score=%d", GetName(), m_iAntiCheatScore);
+	}
+}
+
 void CHARACTER::SkipComboAttackByTime(int interval)
 {
 	m_dwSkipComboAttackByTime = get_dword_time() + interval;