client: Fix P2P Linter Error (#307)

Former-commit-id: 5f673dffed4267c1aca8ebfb4fe182798b9b2d2a [formerly 3fd494231ba5a350ab59a86fcf60ae9f56f1da00]
Former-commit-id: 1506dd418121884a8c7a727f8cf03c12e4c93cc3

beacon-chain/blockchain/BUILD.bazel

@@ -10,11 +10,14 @@ go_library(
     visibility = ["//beacon-chain:__subpackages__"],
     deps = [
         "//beacon-chain/database:go_default_library",
+        "//beacon-chain/params:go_default_library",
         "//beacon-chain/types:go_default_library",
+        "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_ethereum_go_ethereum//ethdb:go_default_library",
         "@com_github_ethereum_go_ethereum//rlp:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@com_github_syndtr_goleveldb//leveldb/errors:go_default_library",
+        "@org_golang_x_crypto//blake2s:go_default_library",
     ],
 )
 
@@ -27,6 +30,7 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//beacon-chain/database:go_default_library",
+        "//beacon-chain/params:go_default_library",
         "//beacon-chain/types:go_default_library",
         "@com_github_ethereum_go_ethereum//common:go_default_library",
         "@com_github_sirupsen_logrus//hooks/test:go_default_library",

beacon-chain/blockchain/core.go

@@ -1,14 +1,18 @@
 package blockchain
 
 import (
+	"errors"
 	"fmt"
 	"sync"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/prysmaticlabs/prysm/beacon-chain/params"
 	"github.com/prysmaticlabs/prysm/beacon-chain/types"
 	log "github.com/sirupsen/logrus"
 	leveldberrors "github.com/syndtr/goleveldb/leveldb/errors"
+	"golang.org/x/crypto/blake2s"
 )
 
 var stateLookupKey = "beaconchainstate"
@@ -85,3 +89,36 @@ func (b *BeaconChain) persist() error {
 	}
 	return b.db.Put([]byte(stateLookupKey), encodedState)
 }
+
+// Shuffle returns a list of pseudorandomly sampled
+// indices to use to select attesters and proposers.
+func Shuffle(seed common.Hash, validatorCount int) ([]int, error) {
+	if validatorCount > params.MaxValidators {
+		return nil, errors.New("Validator count has exceeded MaxValidator Count")
+	}
+
+	// construct a list of indices up to MaxValidators
+	validatorList := make([]int, validatorCount)
+	for i := range validatorList {
+		validatorList[i] = i
+	}
+
+	hashSeed, err := blake2s.New256(seed[:])
+	if err != nil {
+		return nil, err
+	}
+
+	hashSeedByte := hashSeed.Sum(nil)
+
+	// shuffle stops at the second to last index
+	for i := 0; i < validatorCount-1; i++ {
+		// convert every 3 bytes to random number, replace validator index with that number
+		for j := 0; j+3 < len(hashSeedByte); j += 3 {
+			swapNum := int(hashSeedByte[j] + hashSeedByte[j+1] + hashSeedByte[j+2])
+			remaining := validatorCount - i
+			swapPos := swapNum%remaining + i
+			validatorList[i], validatorList[swapPos] = validatorList[swapPos], validatorList[i]
+		}
+	}
+	return validatorList, nil
+}

beacon-chain/blockchain/core_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/prysmaticlabs/prysm/beacon-chain/database"
+	"github.com/prysmaticlabs/prysm/beacon-chain/params"
 	"github.com/prysmaticlabs/prysm/beacon-chain/types"
 	logTest "github.com/sirupsen/logrus/hooks/test"
 )
@@ -119,3 +120,27 @@ func TestMutateCrystallizedState(t *testing.T) {
 		t.Errorf("crystallized state current checkpoint incorrect. wanted %v, got %v", crystallized.CurrentCheckpoint.Hex(), newBeaconChain.state.CrystallizedState.CurrentCheckpoint.Hex())
 	}
 }
+
+func TestFaultyShuffle(t *testing.T) {
+	if _, err := Shuffle(common.Hash{'a'}, params.MaxValidators+1); err == nil {
+		t.Error("Shuffle should have failed when validator count exceeds MaxValidators")
+	}
+}
+
+func TestShuffle(t *testing.T) {
+	hash1 := common.BytesToHash([]byte{'a', 'b', 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'a', 'b', 'c', 'd', 'e', 'f', 'g'})
+	hash2 := common.BytesToHash([]byte{'1', '2', '3', '4', '5', '6', '7', '1', '2', '3', '4', '5', '6', '7', '1', '2', '3', '4', '5', '6', '7', '1', '2', '3', '4', '5', '6', '7', '1', '2', '3', '4', '5', '6', '7'})
+
+	list1, err := Shuffle(hash1, 100)
+	if err != nil {
+		t.Errorf("Shuffle failed with: %v", err)
+	}
+
+	list2, err := Shuffle(hash2, 100)
+	if err != nil {
+		t.Errorf("Shuffle failed with: %v", err)
+	}
+	if reflect.DeepEqual(list1, list2) {
+		t.Errorf("2 shuffled lists shouldn't be equal")
+	}
+}

beacon-chain/params/config.go

@@ -14,7 +14,7 @@ const (
 	// DefaultSwitchDynasty value.
 	DefaultSwitchDynasty = 9999999999999999999
 	// MaxValidators in the protocol.
-	MaxValidators = 2 ^ 24
+	MaxValidators = 4194304
 	// NotariesPerCrosslink fixed to 100.
 	NotariesPerCrosslink = 100
 )

client/p2p/service_test.go

@@ -36,16 +36,16 @@ func TestLifecycle(t *testing.T) {
 	}
 
 	s.Start()
-	msg := hook.Entries[0]
+	msg := hook.Entries[0].Message
 	want := "Starting shardp2p server"
-	if msg == nil || msg.Message != want {
+	if msg != want {
 		t.Errorf("incorrect log. wanted: %s. got: %v", want, msg)
 	}
 
 	s.Stop()
-	msg = hook.LastEntry()
+	msg = hook.LastEntry().Message
 	want = "Stopping shardp2p server"
-	if msg == nil || msg.Message != want {
+	if msg != want {
 		t.Errorf("incorrect log. wanted: %s. got: %v", want, msg)
 	}
 

contracts/deployVRC/README.md

@@ -11,13 +11,13 @@ This is a utility to help users deploy validator registration contract for runni
    deployVRC [global options] command [command options] [arguments...]
 
 *Flags:*  
-   **--keystoreUTCPath**    Keystore UTC file to unlock account (default: "./datadir/keystore/UTC...")
-   **--ipcPath**        Filename for IPC socket/pipe within the datadir (default: "./geth.ipc")
-   **--httpPath**      HTTP-RPC server listening interface (default: "http://localhost:8545/")
-   **--passwordFile**   Password file for unlock account (default: "./password.txt")
-   **--privKey**       Private key to unlock account
-   **--help, -h**            show help   
-   **--version, -v**         print the version   
+   **--keystoreUTCPath**    Keystore UTC file to unlock account (default: "./datadir/keystore/UTC...")   
+   **--ipcPath**        Filename for IPC socket/pipe within the datadir (default: "./geth.ipc")   
+   **--httpPath**      HTTP-RPC server listening interface (default: "http://localhost:8545/")   
+   **--passwordFile**   Password file for unlock account (default: "./password.txt")   
+   **--privKey**       Private key to unlock account   
+   **--help, -h**            show help     
+   **--version, -v**         print the version     
 
 ### Example
 To use private key with default RPC:
@@ -27,16 +27,23 @@ bazel run //deployVRC --privKey yourPrivateKey
 
 To use UTC JSON with IPC:
 ```
-bazel run //deployVRC --ipcPath /path/to/your/geth.ipc --UTCPath /path/to/your/keystore/UTCJSON --passwordFile /path/to/your/password.txt
+bazel run //deployVRC --\
+  --ipcPath /path/to/your/geth.ipc \
+  --UTCPath /path/to/your/keystore/UTCJSON \
+  --passwordFile /path/to/your/password.txt
 ```
 To use UTC JSON with RPC:
 ```
-bazel run //deployVRC --httpPath http://localhost:8545/  --UTCPath /path/to/your/keystore/UTCJSON --passwordFile /path/to/your/password.txt
+bazel run //deployVRC --\
+  --httpPath http://localhost:8545/  \
+  --UTCPath /path/to/your/keystore/UTCJSON \
+  --passwordFile /path/to/your/password.txt
 ```
 or
 ```
-bazel run //deployVRC --UTCPath /path/to/your/keystore/UTCJSON --passwordFile /path/to/your/password.txt
-
+bazel run //deployVRC --\
+  --UTCPath /path/to/your/keystore/UTCJSON \
+  --passwordFile /path/to/your/password.txt
 ```
 
 ### Output