ntfy/server/visitor.go
2023-01-23 14:05:41 -05:00

332 lines
9.8 KiB
Go

package server
import (
"errors"
"fmt"
"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
// visitorDefaultReservationsLimit is the amount of topic names a user without a tier is allowed to reserve.
// This number is zero, and changing it may have unintended consequences in the web app, or otherwise
visitorDefaultReservationsLimit = int64(0)
)
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
userManager *user.Manager // May be nil!
ip netip.Addr
user *user.User
messages int64 // Number of messages sent, reset every day
emails int64 // Number of emails sent, reset every day
requestLimiter *rate.Limiter // Rate limiter for (almost) all requests (including messages)
messagesLimiter util.Limiter // Rate limiter for messages, may be nil
emailsLimiter *rate.Limiter // Rate limiter for emails
subscriptionLimiter util.Limiter // Fixed limiter for active subscriptions (ongoing connections)
bandwidthLimiter util.Limiter // Limiter for attachment bandwidth downloads
accountLimiter *rate.Limiter // Rate limiter for account creation
firebase time.Time // Next allowed Firebase message
seen time.Time // Last seen time of this visitor (needed for removal of stale visitors)
mu sync.Mutex
}
type visitorInfo struct {
Limits *visitorLimits
Stats *visitorStats
}
type visitorLimits struct {
Basis visitorLimitBasis
MessagesLimit int64
MessagesExpiryDuration time.Duration
EmailsLimit int64
ReservationsLimit int64
AttachmentTotalSizeLimit int64
AttachmentFileSizeLimit int64
AttachmentExpiryDuration time.Duration
}
type visitorStats struct {
Messages int64
MessagesRemaining int64
Emails int64
EmailsRemaining int64
Reservations int64
ReservationsRemaining int64
AttachmentTotalSize int64
AttachmentTotalSizeRemaining int64
}
// visitorLimitBasis describes how the visitor limits were derived, either from a user's
// IP address (default config), or from its tier
type visitorLimitBasis string
const (
visitorLimitBasisIP = visitorLimitBasis("ip")
visitorLimitBasisTier = visitorLimitBasis("tier")
)
func newVisitor(conf *Config, messageCache *messageCache, userManager *user.Manager, ip netip.Addr, user *user.User) *visitor {
var messagesLimiter util.Limiter
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.Tier != nil {
requestLimiter = rate.NewLimiter(dailyLimitToRate(user.Tier.MessagesLimit), conf.VisitorRequestLimitBurst)
messagesLimiter = util.NewFixedLimiter(user.Tier.MessagesLimit)
emailsLimiter = rate.NewLimiter(dailyLimitToRate(user.Tier.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,
userManager: userManager, // May be nil
ip: ip,
user: user,
messages: messages,
emails: emails,
requestLimiter: requestLimiter,
messagesLimiter: messagesLimiter, // May be nil
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) String() string {
v.mu.Lock()
defer v.mu.Unlock()
if v.user != nil && v.user.Billing.StripeCustomerID != "" {
return fmt.Sprintf("%s/%s/%s", v.ip.String(), v.user.ID, v.user.Billing.StripeCustomerID)
} else if v.user != nil {
return fmt.Sprintf("%s/%s", v.ip.String(), v.user.ID)
}
return v.ip.String()
}
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) MessageAllowed() error {
if v.messagesLimiter != nil && v.messagesLimiter.Allow(1) != nil {
return errVisitorLimitReached
}
return nil
}
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) IncrementMessages() {
v.mu.Lock()
defer v.mu.Unlock()
v.messages++
if v.user != nil {
v.user.Stats.Messages = v.messages
}
}
func (v *visitor) IncrementEmails() {
v.mu.Lock()
defer v.mu.Unlock()
v.emails++
if v.user != nil {
v.user.Stats.Emails = v.emails
}
}
func (v *visitor) ResetStats() {
v.mu.Lock()
defer v.mu.Unlock()
v.messages = 0
v.emails = 0
if v.user != nil {
v.user.Stats.Messages = 0
v.user.Stats.Emails = 0
// v.messagesLimiter = ... // FIXME
}
}
// SetUser sets the visitors user to the given value
func (v *visitor) SetUser(u *user.User) {
v.mu.Lock()
defer v.mu.Unlock()
v.user = u
}
// MaybeUserID returns the user ID of the visitor (if any). If this is an anonymous visitor,
// an empty string is returned.
func (v *visitor) MaybeUserID() string {
v.mu.Lock()
defer v.mu.Unlock()
if v.user != nil {
return v.user.ID
}
return ""
}
func (v *visitor) Limits() *visitorLimits {
v.mu.Lock()
defer v.mu.Unlock()
limits := defaultVisitorLimits(v.config)
if v.user != nil && v.user.Tier != nil {
limits.Basis = visitorLimitBasisTier
limits.MessagesLimit = v.user.Tier.MessagesLimit
limits.MessagesExpiryDuration = v.user.Tier.MessagesExpiryDuration
limits.EmailsLimit = v.user.Tier.EmailsLimit
limits.ReservationsLimit = v.user.Tier.ReservationsLimit
limits.AttachmentTotalSizeLimit = v.user.Tier.AttachmentTotalSizeLimit
limits.AttachmentFileSizeLimit = v.user.Tier.AttachmentFileSizeLimit
limits.AttachmentExpiryDuration = v.user.Tier.AttachmentExpiryDuration
}
return limits
}
func (v *visitor) Info() (*visitorInfo, error) {
v.mu.Lock()
messages := v.messages
emails := v.emails
v.mu.Unlock()
var attachmentsBytesUsed int64
var err error
if v.user != nil {
attachmentsBytesUsed, err = v.messageCache.AttachmentBytesUsedByUser(v.user.ID)
} else {
attachmentsBytesUsed, err = v.messageCache.AttachmentBytesUsedBySender(v.ip.String())
}
if err != nil {
return nil, err
}
var reservations int64
if v.user != nil && v.userManager != nil {
reservations, err = v.userManager.ReservationsCount(v.user.Name)
if err != nil {
return nil, err
}
}
limits := v.Limits()
stats := &visitorStats{
Messages: messages,
MessagesRemaining: zeroIfNegative(limits.MessagesLimit - messages),
Emails: emails,
EmailsRemaining: zeroIfNegative(limits.EmailsLimit - emails),
Reservations: reservations,
ReservationsRemaining: zeroIfNegative(limits.ReservationsLimit - reservations),
AttachmentTotalSize: attachmentsBytesUsed,
AttachmentTotalSizeRemaining: zeroIfNegative(limits.AttachmentTotalSizeLimit - attachmentsBytesUsed),
}
return &visitorInfo{
Limits: limits,
Stats: 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)
}
func defaultVisitorLimits(conf *Config) *visitorLimits {
return &visitorLimits{
Basis: visitorLimitBasisIP,
MessagesLimit: replenishDurationToDailyLimit(conf.VisitorRequestLimitReplenish),
MessagesExpiryDuration: conf.CacheDuration,
EmailsLimit: replenishDurationToDailyLimit(conf.VisitorEmailLimitReplenish),
ReservationsLimit: visitorDefaultReservationsLimit,
AttachmentTotalSizeLimit: conf.VisitorAttachmentTotalSizeLimit,
AttachmentFileSizeLimit: conf.AttachmentFileSizeLimit,
AttachmentExpiryDuration: conf.AttachmentExpiryDuration,
}
}