// ID returns the ID of a given Conn.
func ID(c Conn) string {
	l := fmt.Sprintf("%s/%s", c.LocalMultiaddr(), c.LocalPeer().Pretty())
	r := fmt.Sprintf("%s/%s", c.RemoteMultiaddr(), c.RemotePeer().Pretty())
	lh := u.Hash([]byte(l))
	rh := u.Hash([]byte(r))
	ch := u.XOR(lh, rh)
	return peer.ID(ch).Pretty()
}

func TestRoutingResolve(t *testing.T) {
	d := mockrouting.NewServer().Client(testutil.RandIdentityOrFatal(t))
	dstore := ds.NewMapDatastore()

	resolver := NewRoutingResolver(d, 0)
	publisher := NewRoutingPublisher(d, dstore)

	privk, pubk, err := testutil.RandTestKeyPair(512)
	if err != nil {
		t.Fatal(err)
	}

	h := path.FromString("/ipfs/QmZULkCELmmk5XNfCgTnCyFgAVxBRBXyDHGGMVoLFLiXEN")
	err = publisher.Publish(context.Background(), privk, h)
	if err != nil {
		t.Fatal(err)
	}

	pubkb, err := pubk.Bytes()
	if err != nil {
		t.Fatal(err)
	}

	pkhash := u.Hash(pubkb)
	res, err := resolver.Resolve(context.Background(), key.Key(pkhash).Pretty())
	if err != nil {
		t.Fatal(err)
	}

	if res != h {
		t.Fatal("Got back incorrect value.")
	}
}

// KeyHash hashes a key.
func KeyHash(k Key) ([]byte, error) {
	kb, err := k.Bytes()
	if err != nil {
		return nil, err
	}
	return u.Hash(kb), nil
}

// RandPeerID generates random "valid" peer IDs. it does not NEED to generate
// keys because it is as if we lost the key right away. fine to read randomness
// and hash it. to generate proper keys and corresponding PeerID, use:
//  sk, pk, _ := testutil.RandKeyPair()
//  id, _ := peer.IDFromPublicKey(pk)
func RandPeerID() (peer.ID, error) {
	buf := make([]byte, 16)
	if _, err := io.ReadFull(u.NewTimeSeededRand(), buf); err != nil {
		return "", err
	}
	h := u.Hash(buf)
	return peer.ID(h), nil
}

// IDFromPublicKey returns the Peer ID corresponding to pk
func IDFromPublicKey(pk ic.PubKey) (ID, error) {
	b, err := pk.Bytes()
	if err != nil {
		return "", err
	}
	hash := u.Hash(b)
	return ID(hash), nil
}

// NewBlockWithHash creates a new block when the hash of the data
// is already known, this is used to save time in situations where
// we are able to be confident that the data is correct
func NewBlockWithHash(data []byte, h mh.Multihash) (*Block, error) {
	if u.Debug {
		chk := u.Hash(data)
		if string(chk) != string(h) {
			return nil, errors.New("Data did not match given hash!")
		}
	}
	return &Block{Data: data, Multihash: h}, nil
}

// ValidatePublicKeyRecord implements ValidatorFunc and
// verifies that the passed in record value is the PublicKey
// that matches the passed in key.
func ValidatePublicKeyRecord(k key.Key, val []byte) error {
	keyparts := bytes.Split([]byte(k), []byte("/"))
	if len(keyparts) < 3 {
		return errors.New("invalid key")
	}

	pkh := u.Hash(val)
	if !bytes.Equal(keyparts[2], pkh) {
		return errors.New("public key does not match storage key")
	}
	return nil
}

// Encoded returns the encoded raw data version of a Node instance.
// It may use a cached encoded version, unless the force flag is given.
func (n *Node) Encoded(force bool) ([]byte, error) {
	sort.Stable(LinkSlice(n.Links)) // keep links sorted
	if n.encoded == nil || force {
		var err error
		n.encoded, err = n.Marshal()
		if err != nil {
			return []byte{}, err
		}
		n.cached = u.Hash(n.encoded)
	}

	return n.encoded, nil
}

func (ks *keyset) generate() error {
	var err error
	ks.sk, ks.pk, err = tu.RandTestKeyPair(512)
	if err != nil {
		return err
	}

	bpk, err := ks.pk.Bytes()
	if err != nil {
		return err
	}

	ks.hpk = string(u.Hash(bpk))
	ks.hpkp = b58.Encode([]byte(ks.hpk))
	return nil
}

func TestBlocks(t *testing.T) {
	bstore := blockstore.NewBlockstore(dssync.MutexWrap(ds.NewMapDatastore()))
	bs, err := New(bstore, offline.Exchange(bstore))
	if err != nil {
		t.Error("failed to construct block service", err)
		return
	}
	defer bs.Close()

	b := blocks.NewBlock([]byte("beep boop"))
	h := u.Hash([]byte("beep boop"))
	if !bytes.Equal(b.Multihash, h) {
		t.Error("Block Multihash and data multihash not equal")
	}

	if b.Key() != key.Key(h) {
		t.Error("Block key and data multihash key not equal")
	}

	k, err := bs.AddBlock(b)
	if err != nil {
		t.Error("failed to add block to BlockService", err)
		return
	}

	if k != b.Key() {
		t.Error("returned key is not equal to block key", err)
	}

	ctx, _ := context.WithTimeout(context.TODO(), time.Second*5)
	b2, err := bs.GetBlock(ctx, b.Key())
	if err != nil {
		t.Error("failed to retrieve block from BlockService", err)
		return
	}

	if b.Key() != b2.Key() {
		t.Error("Block keys not equal.")
	}

	if !bytes.Equal(b.Data, b2.Data) {
		t.Error("Block data is not equal.")
	}
}

// Publish implements Publisher. Accepts a keypair and a value,
// and publishes it out to the routing system
func (p *ipnsPublisher) Publish(ctx context.Context, k ci.PrivKey, value path.Path) error {
	log.Debugf("Publish %s", value)

	data, err := createRoutingEntryData(k, value)
	if err != nil {
		return err
	}
	pubkey := k.GetPublic()
	pkbytes, err := pubkey.Bytes()
	if err != nil {
		return err
	}

	nameb := u.Hash(pkbytes)
	namekey := key.Key("/pk/" + string(nameb))

	log.Debugf("Storing pubkey at: %s", namekey)
	// Store associated public key
	timectx, cancel := context.WithDeadline(ctx, time.Now().Add(time.Second*10))
	defer cancel()
	err = p.routing.PutValue(timectx, namekey, pkbytes)
	if err != nil {
		return err
	}

	ipnskey := key.Key("/ipns/" + string(nameb))

	log.Debugf("Storing ipns entry at: %s", ipnskey)
	// Store ipns entry at "/ipns/"+b58(h(pubkey))
	timectx, cancel = context.WithDeadline(ctx, time.Now().Add(time.Second*10))
	defer cancel()
	if err := p.routing.PutValue(timectx, ipnskey, data); err != nil {
		return err
	}

	return nil
}

func (ks *keyset) load(hpkp, skBytesStr string) error {
	skBytes, err := base64.StdEncoding.DecodeString(skBytesStr)
	if err != nil {
		return err
	}

	ks.sk, err = ic.UnmarshalPrivateKey(skBytes)
	if err != nil {
		return err
	}

	ks.pk = ks.sk.GetPublic()
	bpk, err := ks.pk.Bytes()
	if err != nil {
		return err
	}

	ks.hpk = string(u.Hash(bpk))
	ks.hpkp = b58.Encode([]byte(ks.hpk))
	if ks.hpkp != hpkp {
		return fmt.Errorf("hpkp doesn't match key. %s", hpkp)
	}
	return nil
}

// NewBlock creates a Block object from opaque data. It will hash the data.
func NewBlock(data []byte) *Block {
	return &Block{Data: data, Multihash: u.Hash(data)}
}

// runBootstrap builds up list of peers by requesting random peer IDs
func (dht *IpfsDHT) runBootstrap(ctx context.Context, cfg BootstrapConfig) error {
	bslog := func(msg string) {
		log.Debugf("DHT %s dhtRunBootstrap %s -- routing table size: %d", dht.self, msg, dht.routingTable.Size())
	}
	bslog("start")
	defer bslog("end")
	defer log.EventBegin(ctx, "dhtRunBootstrap").Done()

	var merr u.MultiErr

	randomID := func() peer.ID {
		// 16 random bytes is not a valid peer id. it may be fine becuase
		// the dht will rehash to its own keyspace anyway.
		id := make([]byte, 16)
		rand.Read(id)
		id = u.Hash(id)
		return peer.ID(id)
	}

	// bootstrap sequentially, as results will compound
	ctx, cancel := context.WithTimeout(ctx, cfg.Timeout)
	defer cancel()
	runQuery := func(ctx context.Context, id peer.ID) {
		p, err := dht.FindPeer(ctx, id)
		if err == routing.ErrNotFound {
			// this isn't an error. this is precisely what we expect.
		} else if err != nil {
			merr = append(merr, err)
		} else {
			// woah, actually found a peer with that ID? this shouldn't happen normally
			// (as the ID we use is not a real ID). this is an odd error worth logging.
			err := fmt.Errorf("Bootstrap peer error: Actually FOUND peer. (%s, %s)", id, p)
			log.Warningf("%s", err)
			merr = append(merr, err)
		}
	}

	sequential := true
	if sequential {
		// these should be parallel normally. but can make them sequential for debugging.
		// note that the core/bootstrap context deadline should be extended too for that.
		for i := 0; i < cfg.Queries; i++ {
			id := randomID()
			log.Debugf("Bootstrapping query (%d/%d) to random ID: %s", i+1, cfg.Queries, id)
			runQuery(ctx, id)
		}

	} else {
		// note on parallelism here: the context is passed in to the queries, so they
		// **should** exit when it exceeds, making this function exit on ctx cancel.
		// normally, we should be selecting on ctx.Done() here too, but this gets
		// complicated to do with WaitGroup, and doesnt wait for the children to exit.
		var wg sync.WaitGroup
		for i := 0; i < cfg.Queries; i++ {
			wg.Add(1)
			go func() {
				defer wg.Done()

				id := randomID()
				log.Debugf("Bootstrapping query (%d/%d) to random ID: %s", i+1, cfg.Queries, id)
				runQuery(ctx, id)
			}()
		}
		wg.Wait()
	}

	if len(merr) > 0 {
		return merr
	}
	return nil
}

func newPeerTime(t time.Time) peer.ID {
	s := fmt.Sprintf("hmmm time: %v", t)
	h := u.Hash([]byte(s))
	return peer.ID(h)
}

// runHandshake performs initial communication over insecure channel to share
// keys, IDs, and initiate communication, assigning all necessary params.
// requires the duplex channel to be a msgio.ReadWriter (for framed messaging)
func (s *secureSession) runHandshake() error {
	ctx, cancel := context.WithTimeout(s.ctx, HandshakeTimeout) // remove
	defer cancel()

	// =============================================================================
	// step 1. Propose -- propose cipher suite + send pubkeys + nonce

	// Generate and send Hello packet.
	// Hello = (rand, PublicKey, Supported)
	nonceOut := make([]byte, nonceSize)
	_, err := rand.Read(nonceOut)
	if err != nil {
		return err
	}

	defer log.EventBegin(ctx, "secureHandshake", s).Done()

	s.local.permanentPubKey = s.localKey.GetPublic()
	myPubKeyBytes, err := s.local.permanentPubKey.Bytes()
	if err != nil {
		return err
	}

	proposeOut := new(pb.Propose)
	proposeOut.Rand = nonceOut
	proposeOut.Pubkey = myPubKeyBytes
	proposeOut.Exchanges = &SupportedExchanges
	proposeOut.Ciphers = &SupportedCiphers
	proposeOut.Hashes = &SupportedHashes

	// log.Debugf("1.0 Propose: nonce:%s exchanges:%s ciphers:%s hashes:%s",
	// 	nonceOut, SupportedExchanges, SupportedCiphers, SupportedHashes)

	// Send Propose packet (respects ctx)
	proposeOutBytes, err := writeMsgCtx(ctx, s.insecureM, proposeOut)
	if err != nil {
		return err
	}

	// Receive + Parse their Propose packet and generate an Exchange packet.
	proposeIn := new(pb.Propose)
	proposeInBytes, err := readMsgCtx(ctx, s.insecureM, proposeIn)
	if err != nil {
		return err
	}

	// log.Debugf("1.0.1 Propose recv: nonce:%s exchanges:%s ciphers:%s hashes:%s",
	// 	proposeIn.GetRand(), proposeIn.GetExchanges(), proposeIn.GetCiphers(), proposeIn.GetHashes())

	// =============================================================================
	// step 1.1 Identify -- get identity from their key

	// get remote identity
	s.remote.permanentPubKey, err = ci.UnmarshalPublicKey(proposeIn.GetPubkey())
	if err != nil {
		return err
	}

	// get peer id
	s.remotePeer, err = peer.IDFromPublicKey(s.remote.permanentPubKey)
	if err != nil {
		return err
	}

	log.Debugf("1.1 Identify: %s Remote Peer Identified as %s", s.localPeer, s.remotePeer)

	// =============================================================================
	// step 1.2 Selection -- select/agree on best encryption parameters

	// to determine order, use cmp(H(remote_pubkey||local_rand), H(local_pubkey||remote_rand)).
	oh1 := u.Hash(append(proposeIn.GetPubkey(), nonceOut...))
	oh2 := u.Hash(append(myPubKeyBytes, proposeIn.GetRand()...))
	order := bytes.Compare(oh1, oh2)
	if order == 0 {
		return ErrEcho // talking to self (same socket. must be reuseport + dialing self)
	}

	s.local.curveT, err = selectBest(order, SupportedExchanges, proposeIn.GetExchanges())
	if err != nil {
		return err
	}

	s.local.cipherT, err = selectBest(order, SupportedCiphers, proposeIn.GetCiphers())
	if err != nil {
		return err
	}

	s.local.hashT, err = selectBest(order, SupportedHashes, proposeIn.GetHashes())
	if err != nil {
		return err
	}

	// we use the same params for both directions (must choose same curve)
	// WARNING: if they dont SelectBest the same way, this won't work...
	s.remote.curveT = s.local.curveT
	s.remote.cipherT = s.local.cipherT
	s.remote.hashT = s.local.hashT
//.........这里部分代码省略.........