removed old identify

identify/identify.go

-// Package identify handles how peers identify with eachother upon
-// connection to the network
-package identify
-
-import (
-	"bytes"
-	"errors"
-	"strings"
-
-	"crypto/aes"
-	"crypto/cipher"
-	"crypto/hmac"
-	"crypto/rand"
-	"crypto/sha1"
-	"crypto/sha256"
-	"crypto/sha512"
-	"hash"
-
-	proto "github.com/jbenet/go-ipfs/Godeps/_workspace/src/code.google.com/p/goprotobuf/proto"
-	ci "github.com/jbenet/go-ipfs/crypto"
-	peer "github.com/jbenet/go-ipfs/peer"
-	u "github.com/jbenet/go-ipfs/util"
-)
-
-// List of supported protocols--each section in order of preference.
-// Takes the form:  ECDH curves : Ciphers : Hashes
-var SupportedExchanges = "P-256,P-224,P-384,P-521"
-var SupportedCiphers = "AES-256,AES-128"
-var SupportedHashes = "SHA256,SHA512,SHA1"
-
-// ErrUnsupportedKeyType is returned when a private key cast/type switch fails.
-var ErrUnsupportedKeyType = errors.New("unsupported key type")
-
-// Performs initial communication with this peer to share node ID's and
-// initiate communication.  (secureIn, secureOut, error)
-func Handshake(self, remote *peer.Peer, in <-chan []byte, out chan<- []byte) (<-chan []byte, chan<- []byte, error) {
-	// Generate and send Hello packet.
-	// Hello = (rand, PublicKey, Supported)
-	nonce := make([]byte, 16)
-	_, err := rand.Read(nonce)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	hello := new(Hello)
-
-	myPubKey, err := self.PubKey.Bytes()
-	if err != nil {
-		return nil, nil, err
-	}
-
-	hello.Rand = nonce
-	hello.Pubkey = myPubKey
-	hello.Exchanges = &SupportedExchanges
-	hello.Ciphers = &SupportedCiphers
-	hello.Hashes = &SupportedHashes
-
-	encoded, err := proto.Marshal(hello)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	out <- encoded
-
-	// Parse their Hello packet and generate an Exchange packet.
-	// Exchange = (EphemeralPubKey, Signature)
-	resp := <-in
-
-	helloResp := new(Hello)
-	err = proto.Unmarshal(resp, helloResp)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	remote.PubKey, err = ci.UnmarshalPublicKey(helloResp.GetPubkey())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	remote.ID, err = IDFromPubKey(remote.PubKey)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	exchange, err := selectBest(SupportedExchanges, helloResp.GetExchanges())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	cipherType, err := selectBest(SupportedCiphers, helloResp.GetCiphers())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	hashType, err := selectBest(SupportedHashes, helloResp.GetHashes())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	epubkey, done, err := ci.GenerateEKeyPair(exchange) // Generate EphemeralPubKey
-	if err != nil {
-		return nil, nil, err
-	}
-
-	var handshake bytes.Buffer // Gather corpus to sign.
-	handshake.Write(encoded)
-	handshake.Write(resp)
-	handshake.Write(epubkey)
-
-	exPacket := new(Exchange)
-
-	exPacket.Epubkey = epubkey
-	exPacket.Signature, err = self.PrivKey.Sign(handshake.Bytes())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	exEncoded, err := proto.Marshal(exPacket)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	out <- exEncoded
-
-	// Parse their Exchange packet and generate a Finish packet.
-	// Finish = E('Finish')
-	resp1 := <-in
-
-	exchangeResp := new(Exchange)
-	err = proto.Unmarshal(resp1, exchangeResp)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	var theirHandshake bytes.Buffer
-	_, err = theirHandshake.Write(resp)
-	if err != nil {
-		return nil, nil, err
-	}
-	_, err = theirHandshake.Write(encoded)
-	if err != nil {
-		return nil, nil, err
-	}
-	_, err = theirHandshake.Write(exchangeResp.GetEpubkey())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	ok, err := remote.PubKey.Verify(theirHandshake.Bytes(), exchangeResp.GetSignature())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	if !ok {
-		return nil, nil, errors.New("Bad signature!")
-	}
-
-	secret, err := done(exchangeResp.GetEpubkey())
-	if err != nil {
-		return nil, nil, err
-	}
-
-	cmp := bytes.Compare(myPubKey, helloResp.GetPubkey())
-	mIV, tIV, mCKey, tCKey, mMKey, tMKey := ci.KeyStretcher(cmp, cipherType, hashType, secret)
-
-	secureIn := make(chan []byte)
-	secureOut := make(chan []byte)
-
-	go secureInProxy(in, secureIn, hashType, tIV, tCKey, tMKey)
-	go secureOutProxy(out, secureOut, hashType, mIV, mCKey, mMKey)
-
-	finished := []byte("Finished")
-
-	secureOut <- finished
-	resp2 := <-secureIn
-
-	if bytes.Compare(resp2, finished) != 0 {
-		return nil, nil, errors.New("Negotiation failed.")
-	}
-
-	u.DOut("[%s] identify: Got node id: %s\n", self.ID.Pretty(), remote.ID.Pretty())
-
-	return secureIn, secureOut, nil
-}
-
-func makeMac(hashType string, key []byte) (hash.Hash, int) {
-	switch hashType {
-	case "SHA1":
-		return hmac.New(sha1.New, key), sha1.Size
-	case "SHA512":
-		return hmac.New(sha512.New, key), sha512.Size
-	default:
-		return hmac.New(sha256.New, key), sha256.Size
-	}
-}
-
-func secureInProxy(in <-chan []byte, secureIn chan<- []byte, hashType string, tIV, tCKey, tMKey []byte) {
-	theirBlock, _ := aes.NewCipher(tCKey)
-	theirCipher := cipher.NewCTR(theirBlock, tIV)
-
-	theirMac, macSize := makeMac(hashType, tMKey)
-
-	for {
-		data, ok := <-in
-		if !ok {
-			close(secureIn)
-			return
-		}
-
-		if len(data) <= macSize {
-			continue
-		}
-
-		mark := len(data) - macSize
-		buff := make([]byte, mark)
-
-		theirCipher.XORKeyStream(buff, data[0:mark])
-
-		theirMac.Write(data[0:mark])
-		expected := theirMac.Sum(nil)
-		theirMac.Reset()
-
-		hmacOk := hmac.Equal(data[mark:], expected)
-
-		if hmacOk {
-			secureIn <- buff
-		} else {
-			secureIn <- nil
-		}
-	}
-}
-
-func secureOutProxy(out chan<- []byte, secureOut <-chan []byte, hashType string, mIV, mCKey, mMKey []byte) {
-	myBlock, _ := aes.NewCipher(mCKey)
-	myCipher := cipher.NewCTR(myBlock, mIV)
-
-	myMac, macSize := makeMac(hashType, mMKey)
-
-	for {
-		data, ok := <-secureOut
-		if !ok {
-			close(out)
-			return
-		}
-
-		if len(data) == 0 {
-			continue
-		}
-
-		buff := make([]byte, len(data)+macSize)
-
-		myCipher.XORKeyStream(buff, data)
-
-		myMac.Write(buff[0:len(data)])
-		copy(buff[len(data):], myMac.Sum(nil))
-		myMac.Reset()
-
-		out <- buff
-	}
-}
-
-// IDFromPubKey returns Nodes ID given its public key
-func IDFromPubKey(pk ci.PubKey) (peer.ID, error) {
-	b, err := pk.Bytes()
-	if err != nil {
-		return nil, err
-	}
-	hash, err := u.Hash(b)
-	if err != nil {
-		return nil, err
-	}
-	return peer.ID(hash), nil
-}
-
-// Determines which algorithm to use.  Note:  f(a, b) = f(b, a)
-func selectBest(myPrefs, theirPrefs string) (string, error) {
-	// Person with greatest hash gets first choice.
-	myHash, err := u.Hash([]byte(myPrefs))
-	if err != nil {
-		return "", err
-	}
-
-	theirHash, err := u.Hash([]byte(theirPrefs))
-	if err != nil {
-		return "", err
-	}
-
-	cmp := bytes.Compare(myHash, theirHash)
-	var firstChoiceArr, secChoiceArr []string
-
-	if cmp == -1 {
-		firstChoiceArr = strings.Split(theirPrefs, ",")
-		secChoiceArr = strings.Split(myPrefs, ",")
-	} else if cmp == 1 {
-		firstChoiceArr = strings.Split(myPrefs, ",")
-		secChoiceArr = strings.Split(theirPrefs, ",")
-	} else { // Exact same preferences.
-		myPrefsArr := strings.Split(myPrefs, ",")
-		return myPrefsArr[0], nil
-	}
-
-	for _, secChoice := range secChoiceArr {
-		for _, firstChoice := range firstChoiceArr {
-			if firstChoice == secChoice {
-				return firstChoice, nil
-			}
-		}
-	}
-
-	return "", errors.New("No algorithms in common!")
-}