1 files changed, 129 insertions, 0 deletions
diff --git a/libgo/go/exp/ssh/common.go b/libgo/go/exp/ssh/common.go
new file mode 100644
index 00000000000..739bd2f9c5f
--- /dev/null
+++ b/libgo/go/exp/ssh/common.go
@@ -0,0 +1,129 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssh
+
+import (
+	"big"
+	"strconv"
+	"sync"
+)
+
+// These are string constants in the SSH protocol.
+const (
+	kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1"
+	hostAlgoRSA     = "ssh-rsa"
+	cipherAES128CTR = "aes128-ctr"
+	macSHA196       = "hmac-sha1-96"
+	compressionNone = "none"
+	serviceUserAuth = "ssh-userauth"
+	serviceSSH      = "ssh-connection"
+)
+
+var supportedKexAlgos = []string{kexAlgoDH14SHA1}
+var supportedHostKeyAlgos = []string{hostAlgoRSA}
+var supportedCiphers = []string{cipherAES128CTR}
+var supportedMACs = []string{macSHA196}
+var supportedCompressions = []string{compressionNone}
+
+// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement.
+type dhGroup struct {
+	g, p *big.Int
+}
+
+// dhGroup14 is the group called diffie-hellman-group14-sha1 in RFC 4253 and
+// Oakley Group 14 in RFC 3526.
+var dhGroup14 *dhGroup
+
+var dhGroup14Once sync.Once
+
+func initDHGroup14() {
+	p, _ := new(big.Int).SetString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
+
+	dhGroup14 = &dhGroup{
+		g: new(big.Int).SetInt64(2),
+		p: p,
+	}
+}
+
+// UnexpectedMessageError results when the SSH message that we received didn't
+// match what we wanted.
+type UnexpectedMessageError struct {
+	expected, got uint8
+}
+
+func (u UnexpectedMessageError) String() string {
+	return "ssh: unexpected message type " + strconv.Itoa(int(u.got)) + " (expected " + strconv.Itoa(int(u.expected)) + ")"
+}
+
+// ParseError results from a malformed SSH message.
+type ParseError struct {
+	msgType uint8
+}
+
+func (p ParseError) String() string {
+	return "ssh: parse error in message type " + strconv.Itoa(int(p.msgType))
+}
+
+type handshakeMagics struct {
+	clientVersion, serverVersion []byte
+	clientKexInit, serverKexInit []byte
+}
+
+func findCommonAlgorithm(clientAlgos []string, serverAlgos []string) (commonAlgo string, ok bool) {
+	for _, clientAlgo := range clientAlgos {
+		for _, serverAlgo := range serverAlgos {
+			if clientAlgo == serverAlgo {
+				return clientAlgo, true
+			}
+		}
+	}
+
+	return
+}
+
+func findAgreedAlgorithms(transport *transport, clientKexInit, serverKexInit *kexInitMsg) (kexAlgo, hostKeyAlgo string, ok bool) {
+	kexAlgo, ok = findCommonAlgorithm(clientKexInit.KexAlgos, serverKexInit.KexAlgos)
+	if !ok {
+		return
+	}
+
+	hostKeyAlgo, ok = findCommonAlgorithm(clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos)
+	if !ok {
+		return
+	}
+
+	transport.writer.cipherAlgo, ok = findCommonAlgorithm(clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer)
+	if !ok {
+		return
+	}
+
+	transport.reader.cipherAlgo, ok = findCommonAlgorithm(clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient)
+	if !ok {
+		return
+	}
+
+	transport.writer.macAlgo, ok = findCommonAlgorithm(clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
+	if !ok {
+		return
+	}
+
+	transport.reader.macAlgo, ok = findCommonAlgorithm(clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
+	if !ok {
+		return
+	}
+
+	transport.writer.compressionAlgo, ok = findCommonAlgorithm(clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer)
+	if !ok {
+		return
+	}
+
+	transport.reader.compressionAlgo, ok = findCommonAlgorithm(clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient)
+	if !ok {
+		return
+	}
+
+	ok = true
+	return
+}