add gvisor based service library (#965)

* add service/ library

e2e/helpers.go

@@ -0,0 +1,118 @@
+package e2e
+
+import (
+	"crypto/rand"
+	"io"
+	"net"
+	"time"
+
+	"github.com/slackhq/nebula/cert"
+	"golang.org/x/crypto/curve25519"
+	"golang.org/x/crypto/ed25519"
+)
+
+// NewTestCaCert will generate a CA cert
+func NewTestCaCert(before, after time.Time, ips, subnets []*net.IPNet, groups []string) (*cert.NebulaCertificate, []byte, []byte, []byte) {
+	pub, priv, err := ed25519.GenerateKey(rand.Reader)
+	if before.IsZero() {
+		before = time.Now().Add(time.Second * -60).Round(time.Second)
+	}
+	if after.IsZero() {
+		after = time.Now().Add(time.Second * 60).Round(time.Second)
+	}
+
+	nc := &cert.NebulaCertificate{
+		Details: cert.NebulaCertificateDetails{
+			Name:           "test ca",
+			NotBefore:      time.Unix(before.Unix(), 0),
+			NotAfter:       time.Unix(after.Unix(), 0),
+			PublicKey:      pub,
+			IsCA:           true,
+			InvertedGroups: make(map[string]struct{}),
+		},
+	}
+
+	if len(ips) > 0 {
+		nc.Details.Ips = ips
+	}
+
+	if len(subnets) > 0 {
+		nc.Details.Subnets = subnets
+	}
+
+	if len(groups) > 0 {
+		nc.Details.Groups = groups
+	}
+
+	err = nc.Sign(cert.Curve_CURVE25519, priv)
+	if err != nil {
+		panic(err)
+	}
+
+	pem, err := nc.MarshalToPEM()
+	if err != nil {
+		panic(err)
+	}
+
+	return nc, pub, priv, pem
+}
+
+// NewTestCert will generate a signed certificate with the provided details.
+// Expiry times are defaulted if you do not pass them in
+func NewTestCert(ca *cert.NebulaCertificate, key []byte, name string, before, after time.Time, ip *net.IPNet, subnets []*net.IPNet, groups []string) (*cert.NebulaCertificate, []byte, []byte, []byte) {
+	issuer, err := ca.Sha256Sum()
+	if err != nil {
+		panic(err)
+	}
+
+	if before.IsZero() {
+		before = time.Now().Add(time.Second * -60).Round(time.Second)
+	}
+
+	if after.IsZero() {
+		after = time.Now().Add(time.Second * 60).Round(time.Second)
+	}
+
+	pub, rawPriv := x25519Keypair()
+
+	nc := &cert.NebulaCertificate{
+		Details: cert.NebulaCertificateDetails{
+			Name:           name,
+			Ips:            []*net.IPNet{ip},
+			Subnets:        subnets,
+			Groups:         groups,
+			NotBefore:      time.Unix(before.Unix(), 0),
+			NotAfter:       time.Unix(after.Unix(), 0),
+			PublicKey:      pub,
+			IsCA:           false,
+			Issuer:         issuer,
+			InvertedGroups: make(map[string]struct{}),
+		},
+	}
+
+	err = nc.Sign(ca.Details.Curve, key)
+	if err != nil {
+		panic(err)
+	}
+
+	pem, err := nc.MarshalToPEM()
+	if err != nil {
+		panic(err)
+	}
+
+	return nc, pub, cert.MarshalX25519PrivateKey(rawPriv), pem
+}
+
+func x25519Keypair() ([]byte, []byte) {
+	privkey := make([]byte, 32)
+	if _, err := io.ReadFull(rand.Reader, privkey); err != nil {
+		panic(err)
+	}
+
+	pubkey, err := curve25519.X25519(privkey, curve25519.Basepoint)
+	if err != nil {
+		panic(err)
+	}
+
+	return pubkey, privkey
+}