Generate a filter for a given block

This commit is contained in:
pedro martelletto 2017-01-09 12:00:18 +00:00 committed by Olaoluwa Osuntokun
parent e9298934b9
commit dc25da8296

View file

@ -38,6 +38,7 @@ import (
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/btcsuite/btcutil/bloom"
"github.com/btcsuite/btcutil/gcs"
)
const (
@ -745,8 +746,45 @@ func (sp *serverPeer) OnGetCBFilter(_ *peer.Peer, msg *wire.MsgGetCBFilter) {
return
}
chain := sp.server.blockManager.chain
block, err := chain.BlockByHash(&msg.BlockHash)
if err != nil {
peerLog.Warnf("failed to get block %v: %v", msg.BlockHash, err)
return
}
txSlice := block.Transactions() // XXX can this fail?
txHashes := make([][]byte, len(txSlice))
for i := 0; i < len(txSlice); i++ {
txHash, err := block.TxHash(i)
if err != nil {
peerLog.Warnf("failed to get hash of tx %v of block %v",
i, msg.BlockHash)
return
}
txHashes = append(txHashes, txHash.CloneBytes())
peerLog.Warnf("got hash %v", txHash)
}
var key [gcs.KeySize]byte
P := uint8(20) // collision probability
for i := 0; i < gcs.KeySize; i += 4 {
binary.BigEndian.PutUint32(key[i:],
randomUint32Number(math.MaxUint32))
}
filter, err := gcs.BuildGCSFilter(P, key, txHashes)
if err != nil {
peerLog.Warnf("failed to generate filter for block %v",
msg.BlockHash)
return
}
// XXX pedro: work in progress
peerLog.Warnf("received OnGetCBFilter")
peerLog.Warnf("received OnGetCBFilter: %v", block)
peerLog.Warnf("received OnGetCBFilter: %v", filter)
}
// enforceNodeBloomFlag disconnects the peer if the server is not configured to
@ -975,6 +1013,24 @@ func randomUint16Number(max uint16) uint16 {
}
}
// randomUint32Number returns a random uint32 in a specified input range. Note
// that the range is in zeroth ordering; if you pass it 1800, you will get
// values from 0 to 1800.
func randomUint32Number(max uint32) uint32 {
// In order to avoid modulo bias and ensure every possible outcome in
// [0, max) has equal probability, the random number must be sampled
// from a random source that has a range limited to a multiple of the
// modulus.
var randomNumber uint32
var limitRange = (math.MaxUint32 / max) * max
for {
binary.Read(rand.Reader, binary.LittleEndian, &randomNumber)
if randomNumber < limitRange {
return (randomNumber % max)
}
}
}
// AddRebroadcastInventory adds 'iv' to the list of inventories to be
// rebroadcasted at random intervals until they show up in a block.
func (s *server) AddRebroadcastInventory(iv *wire.InvVect, data interface{}) {