introduce rate limiting of chat

connfilter.go

@@ -166,6 +166,15 @@ where g.game_time < 60000 and g.time_started + $1::interval > now() and (i.pkey
 		}
 	}
 
+	// stage 8 chat rate limit mute
+	if account == nil {
+		rlcDuration, rlcExceeded := ratelimitChatCheck(inst, ip)
+		if rlcExceeded {
+			jd.AllowChat = false
+			jd.Messages = append(jd.Messages, "You were limited to quickchat due to spamming for "+rlcDuration.String())
+		}
+	}
+
 	inst.logger.Printf("connfilter resolved key %v nljoin %v (acc %v) nlplay %v (action %v) nlchat %v (allowed %v)",
 		pubkeyB64,
 		allowNonLinkedJoin, account,

main.go

@@ -24,6 +24,8 @@ func main() {
 
 	go routineDiscordErrorReporter()
 
+	ratelimitChatPenalties = ratelimitChatLoadPenalties()
+
 	recoverInstances()
 
 	signals := make(chan os.Signal, 1)

messageProcessor.go

@@ -386,6 +386,14 @@ func messageHandlerProcessChat(inst *instance, msg string) bool {
 	if msgtype == "WZCHATCMD" && (strings.HasPrefix(string(msgcontent), "/votekick")) {
 		instWriteFmt(inst, `chat direct %s %s`, msgb64pubkey, "If you would like to become a part of Autohoster moderation team, feel free to contact us: https://wz2100-autohost.net/about#contact")
 	}
+	if msgtype == "WZCHATLOB" {
+		ratelimitChatHandleMessage(inst, msgip)
+		rlcDuration, rlcExceeded := ratelimitChatCheck(inst, msgip)
+		if rlcExceeded {
+			instWriteFmt(inst, `set chat quickchat %s`, msgb64pubkey)
+			instWriteFmt(inst, `chat direct %s %s`, msgb64pubkey, "You were limited to quickchat due to spamming for "+rlcDuration.String())
+		}
+	}
 	return false
 }
 

ratelimit.go

@@ -0,0 +1,138 @@
+package main
+
+import (
+	"container/list"
+	"encoding/json"
+	"io/fs"
+	"log"
+	"maps"
+	"os"
+	"sync"
+	"time"
+)
+
+var (
+	ratelimitChatLock      = sync.Mutex{}
+	ratelimitLastCleanup   = time.Now()
+	ratelimitChatData      = map[string]*list.List{}
+	ratelimitChatPenalties = map[string]time.Time{}
+)
+
+func _ratelimitChatSavePenalties() {
+	b, err := json.MarshalIndent(ratelimitChatPenalties, "", "\t")
+	if err != nil {
+		log.Println("Failed to save chat rate limit penalties: ", err)
+		return
+	}
+	perm := fs.FileMode(cfg.GetDInt(644, "filePerms"))
+	os.WriteFile(cfg.GetDString("ratelimitChatPenalties.json", "ratelimitPenaltiesFilename"), b, perm)
+}
+
+func ratelimitChatLoadPenalties() map[string]time.Time {
+	b, err := os.ReadFile(cfg.GetDString("ratelimitChatPenalties.json", "ratelimitPenaltiesFilename"))
+	if err != nil {
+		return map[string]time.Time{}
+	}
+	ret := map[string]time.Time{}
+	if json.Unmarshal(b, &ret) != nil {
+		return map[string]time.Time{}
+	}
+	return ret
+}
+
+func ratelimitChatHandleMessage(inst *instance, ip string) (time.Duration, bool) {
+	ca := tryCfgGetD(tryGetIntGen("ratelimitChatAmount"), 0, inst.cfgs...)
+	if ca <= 0 {
+		return 0, false
+	}
+	ct := tryCfgGetD(tryGetIntGen("ratelimitChatDuration"), 0, inst.cfgs...)
+	if ct <= 0 {
+		return 0, false
+	}
+	ratelimitChatLock.Lock()
+	_ratelimitCleanup()
+	rld, rlt := _ratelimitChatAddMessage(ip, ca, time.Duration(ct)*time.Second)
+	ratelimitChatLock.Unlock()
+	return rld, rlt
+}
+
+func _ratelimitChatAddMessage(ip string, ca int, ct time.Duration) (time.Duration, bool) {
+	l, ok := ratelimitChatData[ip]
+	if !ok {
+		l := list.New()
+		l.PushFront(time.Now())
+		ratelimitChatData[ip] = l
+		return 0, false
+	}
+	l.PushFront(time.Now())
+	if _ratelimitCheckList(l, ca, ct) {
+		lastp, ok := ratelimitChatPenalties[ip]
+		dur := 5 * time.Minute
+		if ok && time.Since(lastp) < 30*time.Minute {
+			dur = 45 * time.Minute
+		}
+		due := time.Now().Add(dur)
+		ratelimitChatPenalties[ip] = due
+		_ratelimitChatSavePenalties()
+		return dur, true
+	}
+	return 0, false
+}
+
+func _ratelimitCheckList(l *list.List, ca int, ct time.Duration) bool {
+	hits := 0
+	for e := l.Front(); e != nil; e = e.Next() {
+		t := e.Value.(time.Time)
+		if time.Since(t) < time.Second*time.Duration(ct) {
+			hits++
+		}
+	}
+	return hits >= ca
+}
+
+func ratelimitChatCheck(_ *instance, ip string) (time.Duration, bool) {
+	ratelimitChatLock.Lock()
+	rld, rlt := _ratelimitChatCheckPenalties(ip)
+	ratelimitChatLock.Unlock()
+	return rld, rlt
+}
+
+func _ratelimitChatCheckPenalties(ip string) (time.Duration, bool) {
+	_ratelimitCleanup()
+	p, ok := ratelimitChatPenalties[ip]
+	if !ok {
+		return 0, false
+	}
+	if p.After(time.Now()) {
+		return time.Until(p), true
+	} else {
+		return 0, false
+	}
+}
+
+func _ratelimitCleanup() {
+	if time.Since(ratelimitLastCleanup) < 5*time.Minute {
+		return
+	}
+	maps.DeleteFunc(ratelimitChatPenalties, func(k string, v time.Time) bool {
+		return time.Since(v) > time.Hour
+	})
+	maps.DeleteFunc(ratelimitChatData, func(k string, v *list.List) bool {
+		return _ratelimitPruneList(v, time.Hour)
+	})
+}
+
+func _ratelimitPruneList(l *list.List, ct time.Duration) bool {
+	toRemove := []*list.Element{}
+	for e := l.Front(); e != nil; e = e.Next() {
+		t := e.Value.(time.Time)
+		if time.Since(t) < ct {
+			el := e
+			toRemove = append(toRemove, el)
+		}
+	}
+	for _, v := range toRemove {
+		l.Remove(v)
+	}
+	return l.Len() == 0
+}