status-go/vendor/github.com/libp2p/go-libp2p-pubsub/validation.go

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package pubsub
import (
"context"
"fmt"
"runtime"
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"sync"
"time"
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"github.com/libp2p/go-libp2p/core/peer"
)
const (
defaultValidateQueueSize = 32
defaultValidateConcurrency = 1024
defaultValidateThrottle = 8192
)
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// ValidationError is an error that may be signalled from message publication when the message
// fails validation
type ValidationError struct {
Reason string
}
func (e ValidationError) Error() string {
return e.Reason
}
// Validator is a function that validates a message with a binary decision: accept or reject.
type Validator func(context.Context, peer.ID, *Message) bool
// ValidatorEx is an extended validation function that validates a message with an enumerated decision
type ValidatorEx func(context.Context, peer.ID, *Message) ValidationResult
// ValidationResult represents the decision of an extended validator
type ValidationResult int
const (
// ValidationAccept is a validation decision that indicates a valid message that should be accepted and
// delivered to the application and forwarded to the network.
ValidationAccept = ValidationResult(0)
// ValidationReject is a validation decision that indicates an invalid message that should not be
// delivered to the application or forwarded to the application. Furthermore the peer that forwarded
// the message should be penalized by peer scoring routers.
ValidationReject = ValidationResult(1)
// ValidationIgnore is a validation decision that indicates a message that should be ignored: it will
// be neither delivered to the application nor forwarded to the network. However, in contrast to
// ValidationReject, the peer that forwarded the message must not be penalized by peer scoring routers.
ValidationIgnore = ValidationResult(2)
// internal
validationThrottled = ValidationResult(-1)
)
// ValidatorOpt is an option for RegisterTopicValidator.
type ValidatorOpt func(addVal *addValReq) error
// validation represents the validator pipeline.
// The validator pipeline performs signature validation and runs a
// sequence of user-configured validators per-topic. It is possible to
// adjust various concurrency parameters, such as the number of
// workers and the max number of simultaneous validations. The user
// can also attach inline validators that will be executed
// synchronously; this may be useful to prevent superfluous
// context-switching for lightweight tasks.
type validation struct {
p *PubSub
tracer *pubsubTracer
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// mx protects the validator map
mx sync.Mutex
// topicVals tracks per topic validators
topicVals map[string]*topicVal
// validateQ is the front-end to the validation pipeline
validateQ chan *validateReq
// validateThrottle limits the number of active validation goroutines
validateThrottle chan struct{}
// this is the number of synchronous validation workers
validateWorkers int
}
// validation requests
type validateReq struct {
vals []*topicVal
src peer.ID
msg *Message
}
// representation of topic validators
type topicVal struct {
topic string
validate ValidatorEx
validateTimeout time.Duration
validateThrottle chan struct{}
validateInline bool
}
// async request to add a topic validators
type addValReq struct {
topic string
validate interface{}
timeout time.Duration
throttle int
inline bool
resp chan error
}
// async request to remove a topic validator
type rmValReq struct {
topic string
resp chan error
}
// newValidation creates a new validation pipeline
func newValidation() *validation {
return &validation{
topicVals: make(map[string]*topicVal),
validateQ: make(chan *validateReq, defaultValidateQueueSize),
validateThrottle: make(chan struct{}, defaultValidateThrottle),
validateWorkers: runtime.NumCPU(),
}
}
// Start attaches the validation pipeline to a pubsub instance and starts background
// workers
func (v *validation) Start(p *PubSub) {
v.p = p
v.tracer = p.tracer
for i := 0; i < v.validateWorkers; i++ {
go v.validateWorker()
}
}
// AddValidator adds a new validator
func (v *validation) AddValidator(req *addValReq) {
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v.mx.Lock()
defer v.mx.Unlock()
topic := req.topic
_, ok := v.topicVals[topic]
if ok {
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req.resp <- fmt.Errorf("duplicate validator for topic %s", topic)
return
}
makeValidatorEx := func(v Validator) ValidatorEx {
return func(ctx context.Context, p peer.ID, msg *Message) ValidationResult {
if v(ctx, p, msg) {
return ValidationAccept
} else {
return ValidationReject
}
}
}
var validator ValidatorEx
switch v := req.validate.(type) {
case func(ctx context.Context, p peer.ID, msg *Message) bool:
validator = makeValidatorEx(Validator(v))
case Validator:
validator = makeValidatorEx(v)
case func(ctx context.Context, p peer.ID, msg *Message) ValidationResult:
validator = ValidatorEx(v)
case ValidatorEx:
validator = v
default:
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req.resp <- fmt.Errorf("unknown validator type for topic %s; must be an instance of Validator or ValidatorEx", topic)
return
}
val := &topicVal{
topic: topic,
validate: validator,
validateTimeout: 0,
validateThrottle: make(chan struct{}, defaultValidateConcurrency),
validateInline: req.inline,
}
if req.timeout > 0 {
val.validateTimeout = req.timeout
}
if req.throttle > 0 {
val.validateThrottle = make(chan struct{}, req.throttle)
}
v.topicVals[topic] = val
req.resp <- nil
}
// RemoveValidator removes an existing validator
func (v *validation) RemoveValidator(req *rmValReq) {
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v.mx.Lock()
defer v.mx.Unlock()
topic := req.topic
_, ok := v.topicVals[topic]
if ok {
delete(v.topicVals, topic)
req.resp <- nil
} else {
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req.resp <- fmt.Errorf("no validator for topic %s", topic)
}
}
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// PushLocal synchronously pushes a locally published message and performs applicable
// validations.
// Returns an error if validation fails
func (v *validation) PushLocal(msg *Message) error {
v.p.tracer.PublishMessage(msg)
err := v.p.checkSigningPolicy(msg)
if err != nil {
return err
}
vals := v.getValidators(msg)
return v.validate(vals, msg.ReceivedFrom, msg, true)
}
// Push pushes a message into the validation pipeline.
// It returns true if the message can be forwarded immediately without validation.
func (v *validation) Push(src peer.ID, msg *Message) bool {
vals := v.getValidators(msg)
if len(vals) > 0 || msg.Signature != nil {
select {
case v.validateQ <- &validateReq{vals, src, msg}:
default:
log.Debugf("message validation throttled: queue full; dropping message from %s", src)
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v.tracer.RejectMessage(msg, RejectValidationQueueFull)
}
return false
}
return true
}
// getValidators returns all validators that apply to a given message
func (v *validation) getValidators(msg *Message) []*topicVal {
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v.mx.Lock()
defer v.mx.Unlock()
topic := msg.GetTopic()
val, ok := v.topicVals[topic]
if !ok {
return nil
}
return []*topicVal{val}
}
// validateWorker is an active goroutine performing inline validation
func (v *validation) validateWorker() {
for {
select {
case req := <-v.validateQ:
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v.validate(req.vals, req.src, req.msg, false)
case <-v.p.ctx.Done():
return
}
}
}
// validate performs validation and only sends the message if all validators succeed
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func (v *validation) validate(vals []*topicVal, src peer.ID, msg *Message, synchronous bool) error {
// If signature verification is enabled, but signing is disabled,
// the Signature is required to be nil upon receiving the message in PubSub.pushMsg.
if msg.Signature != nil {
if !v.validateSignature(msg) {
log.Debugf("message signature validation failed; dropping message from %s", src)
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v.tracer.RejectMessage(msg, RejectInvalidSignature)
return ValidationError{Reason: RejectInvalidSignature}
}
}
// we can mark the message as seen now that we have verified the signature
// and avoid invoking user validators more than once
id := v.p.idGen.ID(msg)
if !v.p.markSeen(id) {
v.tracer.DuplicateMessage(msg)
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return nil
} else {
v.tracer.ValidateMessage(msg)
}
var inline, async []*topicVal
for _, val := range vals {
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if val.validateInline || synchronous {
inline = append(inline, val)
} else {
async = append(async, val)
}
}
// apply inline (synchronous) validators
result := ValidationAccept
loop:
for _, val := range inline {
switch val.validateMsg(v.p.ctx, src, msg) {
case ValidationAccept:
case ValidationReject:
result = ValidationReject
break loop
case ValidationIgnore:
result = ValidationIgnore
}
}
if result == ValidationReject {
log.Debugf("message validation failed; dropping message from %s", src)
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v.tracer.RejectMessage(msg, RejectValidationFailed)
return ValidationError{Reason: RejectValidationFailed}
}
// apply async validators
if len(async) > 0 {
select {
case v.validateThrottle <- struct{}{}:
go func() {
v.doValidateTopic(async, src, msg, result)
<-v.validateThrottle
}()
default:
log.Debugf("message validation throttled; dropping message from %s", src)
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v.tracer.RejectMessage(msg, RejectValidationThrottled)
}
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return nil
}
if result == ValidationIgnore {
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v.tracer.RejectMessage(msg, RejectValidationIgnored)
return ValidationError{Reason: RejectValidationIgnored}
}
// no async validators, accepted message, send it!
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select {
case v.p.sendMsg <- msg:
return nil
case <-v.p.ctx.Done():
return v.p.ctx.Err()
}
}
func (v *validation) validateSignature(msg *Message) bool {
err := verifyMessageSignature(msg.Message)
if err != nil {
log.Debugf("signature verification error: %s", err.Error())
return false
}
return true
}
func (v *validation) doValidateTopic(vals []*topicVal, src peer.ID, msg *Message, r ValidationResult) {
result := v.validateTopic(vals, src, msg)
if result == ValidationAccept && r != ValidationAccept {
result = r
}
switch result {
case ValidationAccept:
v.p.sendMsg <- msg
case ValidationReject:
log.Debugf("message validation failed; dropping message from %s", src)
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v.tracer.RejectMessage(msg, RejectValidationFailed)
return
case ValidationIgnore:
log.Debugf("message validation punted; ignoring message from %s", src)
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v.tracer.RejectMessage(msg, RejectValidationIgnored)
return
case validationThrottled:
log.Debugf("message validation throttled; ignoring message from %s", src)
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v.tracer.RejectMessage(msg, RejectValidationThrottled)
default:
// BUG: this would be an internal programming error, so a panic seems appropiate.
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panic(fmt.Errorf("unexpected validation result: %d", result))
}
}
func (v *validation) validateTopic(vals []*topicVal, src peer.ID, msg *Message) ValidationResult {
if len(vals) == 1 {
return v.validateSingleTopic(vals[0], src, msg)
}
ctx, cancel := context.WithCancel(v.p.ctx)
defer cancel()
rch := make(chan ValidationResult, len(vals))
rcount := 0
for _, val := range vals {
rcount++
select {
case val.validateThrottle <- struct{}{}:
go func(val *topicVal) {
rch <- val.validateMsg(ctx, src, msg)
<-val.validateThrottle
}(val)
default:
log.Debugf("validation throttled for topic %s", val.topic)
rch <- validationThrottled
}
}
result := ValidationAccept
loop:
for i := 0; i < rcount; i++ {
switch <-rch {
case ValidationAccept:
case ValidationReject:
result = ValidationReject
break loop
case ValidationIgnore:
// throttled validation has the same effect, but takes precedence over Ignore as it is not
// known whether the throttled validator would have signaled rejection.
if result != validationThrottled {
result = ValidationIgnore
}
case validationThrottled:
result = validationThrottled
}
}
return result
}
// fast path for single topic validation that avoids the extra goroutine
func (v *validation) validateSingleTopic(val *topicVal, src peer.ID, msg *Message) ValidationResult {
select {
case val.validateThrottle <- struct{}{}:
res := val.validateMsg(v.p.ctx, src, msg)
<-val.validateThrottle
return res
default:
log.Debugf("validation throttled for topic %s", val.topic)
return validationThrottled
}
}
func (val *topicVal) validateMsg(ctx context.Context, src peer.ID, msg *Message) ValidationResult {
start := time.Now()
defer func() {
log.Debugf("validation done; took %s", time.Since(start))
}()
if val.validateTimeout > 0 {
var cancel func()
ctx, cancel = context.WithTimeout(ctx, val.validateTimeout)
defer cancel()
}
r := val.validate(ctx, src, msg)
switch r {
case ValidationAccept:
fallthrough
case ValidationReject:
fallthrough
case ValidationIgnore:
return r
default:
log.Warnf("Unexpected result from validator: %d; ignoring message", r)
return ValidationIgnore
}
}
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// / Options
// WithValidateQueueSize sets the buffer of validate queue. Defaults to 32.
// When queue is full, validation is throttled and new messages are dropped.
func WithValidateQueueSize(n int) Option {
return func(ps *PubSub) error {
if n > 0 {
ps.val.validateQ = make(chan *validateReq, n)
return nil
}
return fmt.Errorf("validate queue size must be > 0")
}
}
// WithValidateThrottle sets the upper bound on the number of active validation
// goroutines across all topics. The default is 8192.
func WithValidateThrottle(n int) Option {
return func(ps *PubSub) error {
ps.val.validateThrottle = make(chan struct{}, n)
return nil
}
}
// WithValidateWorkers sets the number of synchronous validation worker goroutines.
// Defaults to NumCPU.
//
// The synchronous validation workers perform signature validation, apply inline
// user validators, and schedule asynchronous user validators.
// You can adjust this parameter to devote less cpu time to synchronous validation.
func WithValidateWorkers(n int) Option {
return func(ps *PubSub) error {
if n > 0 {
ps.val.validateWorkers = n
return nil
}
return fmt.Errorf("number of validation workers must be > 0")
}
}
// WithValidatorTimeout is an option that sets a timeout for an (asynchronous) topic validator.
// By default there is no timeout in asynchronous validators.
func WithValidatorTimeout(timeout time.Duration) ValidatorOpt {
return func(addVal *addValReq) error {
addVal.timeout = timeout
return nil
}
}
// WithValidatorConcurrency is an option that sets the topic validator throttle.
// This controls the number of active validation goroutines for the topic; the default is 1024.
func WithValidatorConcurrency(n int) ValidatorOpt {
return func(addVal *addValReq) error {
addVal.throttle = n
return nil
}
}
// WithValidatorInline is an option that sets the validation disposition to synchronous:
// it will be executed inline in validation front-end, without spawning a new goroutine.
// This is suitable for simple or cpu-bound validators that do not block.
func WithValidatorInline(inline bool) ValidatorOpt {
return func(addVal *addValReq) error {
addVal.inline = inline
return nil
}
}