storj/pkg/audit/cursor.go
Maximillian von Briesen 66ee332446
Fix audit stuff breaking test-captplanet (#594)
* fix audit stripe selector to work if last segment is smaller than stripe size

* fix audit bug related to indexing an incomplete list of nodes returned by overlay
2018-11-07 16:23:05 -05:00

142 lines
3.3 KiB
Go

// Copyright (C) 2018 Storj Labs, Inc.
// See LICENSE for copying information.
package audit
import (
"context"
"crypto/rand"
"math/big"
"sync"
"github.com/vivint/infectious"
"storj.io/storj/pkg/eestream"
"storj.io/storj/pkg/pb"
"storj.io/storj/pkg/pointerdb/pdbclient"
"storj.io/storj/pkg/storage/meta"
"storj.io/storj/pkg/storj"
)
// Stripe keeps track of a stripe's index and its parent segment
type Stripe struct {
Index int
Segment *pb.Pointer
Authorization *pb.SignedMessage
}
// Cursor keeps track of audit location in pointer db
type Cursor struct {
pointers pdbclient.Client
lastPath storj.Path
mutex sync.Mutex
}
// NewCursor creates a Cursor which iterates over pointer db
func NewCursor(pointers pdbclient.Client) *Cursor {
return &Cursor{pointers: pointers}
}
// NextStripe returns a random stripe to be audited
func (cursor *Cursor) NextStripe(ctx context.Context) (stripe *Stripe, err error) {
cursor.mutex.Lock()
defer cursor.mutex.Unlock()
var pointerItems []pdbclient.ListItem
var path storj.Path
var more bool
if cursor.lastPath == "" {
pointerItems, more, err = cursor.pointers.List(ctx, "", "", "", true, 0, meta.None)
} else {
pointerItems, more, err = cursor.pointers.List(ctx, "", cursor.lastPath, "", true, 0, meta.None)
}
if err != nil {
return nil, err
}
if len(pointerItems) == 0 {
return nil, nil
}
pointerItem, err := getRandomPointer(pointerItems)
if err != nil {
return nil, err
}
path = pointerItem.Path
// keep track of last path listed
if !more {
cursor.lastPath = ""
} else {
cursor.lastPath = pointerItems[len(pointerItems)-1].Path
}
// get pointer info
pointer, _, err := cursor.pointers.Get(ctx, path)
if err != nil {
return nil, err
}
if pointer.GetType() != pb.Pointer_REMOTE {
return nil, nil
}
// create the erasure scheme so we can get the stripe size
es, err := makeErasureScheme(pointer.GetRemote().GetRedundancy())
if err != nil {
return nil, err
}
if pointer.GetSize() == 0 {
return nil, nil
}
index, err := getRandomStripe(es, pointer)
if err != nil {
return nil, err
}
authorization := cursor.pointers.SignedMessage()
return &Stripe{Index: index, Segment: pointer, Authorization: authorization}, nil
}
func makeErasureScheme(rs *pb.RedundancyScheme) (eestream.ErasureScheme, error) {
required := int(rs.GetMinReq())
total := int(rs.GetTotal())
fc, err := infectious.NewFEC(required, total)
if err != nil {
return nil, err
}
es := eestream.NewRSScheme(fc, int(rs.GetErasureShareSize()))
return es, nil
}
func getRandomStripe(es eestream.ErasureScheme, pointer *pb.Pointer) (index int, err error) {
stripeSize := es.StripeSize()
// the last segment could be smaller than stripe size
if pointer.GetSize() < int64(stripeSize) {
return 0, nil
}
randomStripeIndex, err := rand.Int(rand.Reader, big.NewInt(pointer.GetSize()/int64(stripeSize)))
if err != nil {
return -1, err
}
return int(randomStripeIndex.Int64()), nil
}
func getRandomPointer(pointerItems []pdbclient.ListItem) (pointer pdbclient.ListItem, err error) {
randomNum, err := rand.Int(rand.Reader, big.NewInt(int64(len(pointerItems))))
if err != nil {
return pdbclient.ListItem{}, err
}
randomNumInt64 := randomNum.Int64()
pointerItem := pointerItems[randomNumInt64]
return pointerItem, nil
}