package server import ( "errors" "net/netip" "sync" "time" "golang.org/x/time/rate" "heckel.io/ntfy/util" ) const ( // visitorExpungeAfter defines how long a visitor is active before it is removed from memory. This number // has to be very high to prevent e-mail abuse, but it doesn't really affect the other limits anyway, since // they are replenished faster (typically). visitorExpungeAfter = 24 * time.Hour ) var ( errVisitorLimitReached = errors.New("limit reached") ) // visitor represents an API user, and its associated rate.Limiter used for rate limiting type visitor struct { config *Config messageCache *messageCache ip netip.Addr requests *rate.Limiter emails *rate.Limiter subscriptions util.Limiter bandwidth util.Limiter firebase time.Time // Next allowed Firebase message seen time.Time mu sync.Mutex } type visitorStats struct { AttachmentFileSizeLimit int64 `json:"attachmentFileSizeLimit"` VisitorAttachmentBytesTotal int64 `json:"visitorAttachmentBytesTotal"` VisitorAttachmentBytesUsed int64 `json:"visitorAttachmentBytesUsed"` VisitorAttachmentBytesRemaining int64 `json:"visitorAttachmentBytesRemaining"` } func newVisitor(conf *Config, messageCache *messageCache, ip netip.Addr) *visitor { return &visitor{ config: conf, messageCache: messageCache, ip: ip, requests: rate.NewLimiter(rate.Every(conf.VisitorRequestLimitReplenish), conf.VisitorRequestLimitBurst), emails: rate.NewLimiter(rate.Every(conf.VisitorEmailLimitReplenish), conf.VisitorEmailLimitBurst), subscriptions: util.NewFixedLimiter(int64(conf.VisitorSubscriptionLimit)), bandwidth: util.NewBytesLimiter(conf.VisitorAttachmentDailyBandwidthLimit, 24*time.Hour), firebase: time.Unix(0, 0), seen: time.Now(), } } func (v *visitor) RequestAllowed() error { if !v.requests.Allow() { return errVisitorLimitReached } return nil } func (v *visitor) FirebaseAllowed() error { v.mu.Lock() defer v.mu.Unlock() if time.Now().Before(v.firebase) { return errVisitorLimitReached } return nil } func (v *visitor) FirebaseTemporarilyDeny() { v.mu.Lock() defer v.mu.Unlock() v.firebase = time.Now().Add(v.config.FirebaseQuotaExceededPenaltyDuration) } func (v *visitor) EmailAllowed() error { if !v.emails.Allow() { return errVisitorLimitReached } return nil } func (v *visitor) SubscriptionAllowed() error { v.mu.Lock() defer v.mu.Unlock() if err := v.subscriptions.Allow(1); err != nil { return errVisitorLimitReached } return nil } func (v *visitor) RemoveSubscription() { v.mu.Lock() defer v.mu.Unlock() v.subscriptions.Allow(-1) } func (v *visitor) Keepalive() { v.mu.Lock() defer v.mu.Unlock() v.seen = time.Now() } func (v *visitor) BandwidthLimiter() util.Limiter { return v.bandwidth } func (v *visitor) Stale() bool { v.mu.Lock() defer v.mu.Unlock() return time.Since(v.seen) > visitorExpungeAfter } func (v *visitor) Stats() (*visitorStats, error) { attachmentsBytesUsed, err := v.messageCache.AttachmentBytesUsed(v.ip.String()) if err != nil { return nil, err } attachmentsBytesRemaining := v.config.VisitorAttachmentTotalSizeLimit - attachmentsBytesUsed if attachmentsBytesRemaining < 0 { attachmentsBytesRemaining = 0 } return &visitorStats{ AttachmentFileSizeLimit: v.config.AttachmentFileSizeLimit, VisitorAttachmentBytesTotal: v.config.VisitorAttachmentTotalSizeLimit, VisitorAttachmentBytesUsed: attachmentsBytesUsed, VisitorAttachmentBytesRemaining: attachmentsBytesRemaining, }, nil }