package server import ( "errors" "heckel.io/ntfy/user" "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 user *user.User messages int64 // Number of messages sent emails int64 // Number of emails sent requestLimiter *rate.Limiter // Rate limiter for (almost) all requests (including messages) emailsLimiter *rate.Limiter // Rate limiter for emails subscriptionLimiter util.Limiter // Fixed limiter for active subscriptions (ongoing connections) bandwidthLimiter util.Limiter accountLimiter *rate.Limiter // Rate limiter for account creation firebase time.Time // Next allowed Firebase message seen time.Time mu sync.Mutex } type visitorStats struct { Basis string // "ip", "role" or "plan" Messages int64 MessagesLimit int64 MessagesRemaining int64 Emails int64 EmailsLimit int64 EmailsRemaining int64 AttachmentTotalSize int64 AttachmentTotalSizeLimit int64 AttachmentTotalSizeRemaining int64 AttachmentFileSizeLimit int64 } func newVisitor(conf *Config, messageCache *messageCache, ip netip.Addr, user *user.User) *visitor { var requestLimiter, emailsLimiter, accountLimiter *rate.Limiter var messages, emails int64 if user != nil { messages = user.Stats.Messages emails = user.Stats.Emails } else { accountLimiter = rate.NewLimiter(rate.Every(conf.VisitorAccountCreateLimitReplenish), conf.VisitorAccountCreateLimitBurst) } if user != nil && user.Plan != nil { requestLimiter = rate.NewLimiter(dailyLimitToRate(user.Plan.MessagesLimit), conf.VisitorRequestLimitBurst) emailsLimiter = rate.NewLimiter(dailyLimitToRate(user.Plan.EmailsLimit), conf.VisitorEmailLimitBurst) } else { requestLimiter = rate.NewLimiter(rate.Every(conf.VisitorRequestLimitReplenish), conf.VisitorRequestLimitBurst) emailsLimiter = rate.NewLimiter(rate.Every(conf.VisitorEmailLimitReplenish), conf.VisitorEmailLimitBurst) } return &visitor{ config: conf, messageCache: messageCache, ip: ip, user: user, messages: messages, emails: emails, requestLimiter: requestLimiter, emailsLimiter: emailsLimiter, subscriptionLimiter: util.NewFixedLimiter(int64(conf.VisitorSubscriptionLimit)), bandwidthLimiter: util.NewBytesLimiter(conf.VisitorAttachmentDailyBandwidthLimit, 24*time.Hour), accountLimiter: accountLimiter, // May be nil firebase: time.Unix(0, 0), seen: time.Now(), } } func (v *visitor) RequestAllowed() error { if !v.requestLimiter.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.emailsLimiter.Allow() { return errVisitorLimitReached } return nil } func (v *visitor) SubscriptionAllowed() error { v.mu.Lock() defer v.mu.Unlock() if err := v.subscriptionLimiter.Allow(1); err != nil { return errVisitorLimitReached } return nil } func (v *visitor) RemoveSubscription() { v.mu.Lock() defer v.mu.Unlock() v.subscriptionLimiter.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.bandwidthLimiter } func (v *visitor) Stale() bool { v.mu.Lock() defer v.mu.Unlock() return time.Since(v.seen) > visitorExpungeAfter } func (v *visitor) IncrMessages() { v.mu.Lock() defer v.mu.Unlock() v.messages++ if v.user != nil { v.user.Stats.Messages = v.messages } } func (v *visitor) IncrEmails() { v.mu.Lock() defer v.mu.Unlock() v.emails++ if v.user != nil { v.user.Stats.Emails = v.emails } } func (v *visitor) Stats() (*visitorStats, error) { v.mu.Lock() messages := v.messages emails := v.emails v.mu.Unlock() stats := &visitorStats{} if v.user != nil && v.user.Role == user.RoleAdmin { stats.Basis = "role" stats.MessagesLimit = 0 stats.EmailsLimit = 0 stats.AttachmentTotalSizeLimit = 0 stats.AttachmentFileSizeLimit = 0 } else if v.user != nil && v.user.Plan != nil { stats.Basis = "plan" stats.MessagesLimit = v.user.Plan.MessagesLimit stats.EmailsLimit = v.user.Plan.EmailsLimit stats.AttachmentTotalSizeLimit = v.user.Plan.AttachmentTotalSizeLimit stats.AttachmentFileSizeLimit = v.user.Plan.AttachmentFileSizeLimit } else { stats.Basis = "ip" stats.MessagesLimit = replenishDurationToDailyLimit(v.config.VisitorRequestLimitReplenish) stats.EmailsLimit = replenishDurationToDailyLimit(v.config.VisitorEmailLimitReplenish) stats.AttachmentTotalSizeLimit = v.config.VisitorAttachmentTotalSizeLimit stats.AttachmentFileSizeLimit = v.config.AttachmentFileSizeLimit } var attachmentsBytesUsed int64 var err error if v.user != nil { attachmentsBytesUsed, err = v.messageCache.AttachmentBytesUsedByUser(v.user.Name) } else { attachmentsBytesUsed, err = v.messageCache.AttachmentBytesUsedBySender(v.ip.String()) } if err != nil { return nil, err } stats.Messages = messages stats.MessagesRemaining = zeroIfNegative(stats.MessagesLimit - stats.Messages) stats.Emails = emails stats.EmailsRemaining = zeroIfNegative(stats.EmailsLimit - stats.Emails) stats.AttachmentTotalSize = attachmentsBytesUsed stats.AttachmentTotalSizeRemaining = zeroIfNegative(stats.AttachmentTotalSizeLimit - stats.AttachmentTotalSize) return stats, nil } func zeroIfNegative(value int64) int64 { if value < 0 { return 0 } return value } func replenishDurationToDailyLimit(duration time.Duration) int64 { return int64(24 * time.Hour / duration) } func dailyLimitToRate(limit int64) rate.Limit { return rate.Limit(limit) * rate.Every(24*time.Hour) }