From ea5c74e7610ae76ceca155d8705f58ae41999857 Mon Sep 17 00:00:00 2001
From: Pavel Karpy <carpawell@nspcc.ru>
Date: Fri, 18 Jun 2021 13:11:57 +0300
Subject: [PATCH] [#622] pkg/network: Add multiaddress validation

Validation checks:
1. if address can be parsed by network package;
2. if address contains correct amount of protocols;
3. if address's protocols are in correct order.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
---
 pkg/network/validation.go      | 87 ++++++++++++++++++++++++++++++++++
 pkg/network/validation_test.go | 64 +++++++++++++++++++++++++
 2 files changed, 151 insertions(+)
 create mode 100644 pkg/network/validation.go
 create mode 100644 pkg/network/validation_test.go

diff --git a/pkg/network/validation.go b/pkg/network/validation.go
new file mode 100644
index 000000000..66dd5982a
--- /dev/null
+++ b/pkg/network/validation.go
@@ -0,0 +1,87 @@
+package network
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/netmap"
+)
+
+const (
+	// maxProtocolsAmount is maximal amount of protocols
+	// in multiaddress after parsing with network.AddressFromString
+	maxProtocolsAmount = 3
+
+	// minProtocolsAmount is minimal amount of protocols
+	// in multiaddress after parsing with network.AddressFromString:
+	// host(ip) and port.
+	minProtocolsAmount = 2
+
+	// network protocols
+	dns, ip4, ip6 = "dns4", "ip4", "ip6"
+
+	// transport protocols
+	tcp = "tcp"
+)
+
+var (
+	errIncorrectProtocolAmount         = errors.New("numbers of protocols in multiaddress incorrect")
+	errUnsupportedNetworkProtocol      = errors.New("unsupported network protocol in multiaddress")
+	errUnsupportedTransportProtocol    = errors.New("unsupported transport protocol in multiaddress")
+	errUnsupportedPresentationProtocol = errors.New("unsupported presentation protocol in multiaddress")
+)
+
+// VerifyMultiAddress validates multiaddress of n.
+//
+// If n's address contains more than 3 protocols
+// or less than 2 protocols an error returns.
+//
+// If n's address's protocol order is incorrect
+// an error returns.
+//
+// Correct composition(and order from low to high level)
+// of protocols:
+//
+//    1. dns4/ip4/ip6
+//    2. tcp
+//    3. tls(optional, may be absent)
+//
+func VerifyMultiAddress(ni *netmap.NodeInfo) error {
+	// check if it can be parsed to network.Address
+	var netAddr Address
+
+	err := netAddr.FromString(ni.Address())
+	if err != nil {
+		return fmt.Errorf("could not parse multiaddr from NodeInfo: %w", err)
+	}
+
+	// check amount of protocols and its order
+	return checkProtocols(netAddr)
+}
+
+func checkProtocols(a Address) error {
+	pp := a.ma.Protocols()
+	parsedProtocolsAmount := len(pp)
+
+	if parsedProtocolsAmount > maxProtocolsAmount || parsedProtocolsAmount < minProtocolsAmount {
+		return errIncorrectProtocolAmount
+	}
+
+	switch pp[0].Name {
+	case dns, ip4, ip6:
+	default:
+		return errUnsupportedNetworkProtocol
+	}
+
+	if pp[1].Name != tcp {
+		return errUnsupportedTransportProtocol
+	}
+
+	if parsedProtocolsAmount != minProtocolsAmount {
+		if pp[2].Name != tlsProtocolName {
+			return errUnsupportedPresentationProtocol
+		}
+	}
+
+	return nil
+}
diff --git a/pkg/network/validation_test.go b/pkg/network/validation_test.go
new file mode 100644
index 000000000..8409b2915
--- /dev/null
+++ b/pkg/network/validation_test.go
@@ -0,0 +1,64 @@
+package network
+
+import (
+	"testing"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/netmap"
+	"github.com/stretchr/testify/require"
+)
+
+type testCase struct {
+	input string
+	err   error
+}
+
+func TestVerifyMultiAddress_Order(t *testing.T) {
+	testCases := []testCase{
+		{
+			input: "/ip4/1.2.3.4/tcp/80",
+			err:   nil,
+		},
+		{
+			input: "/ip6/1.2.3.4/tcp/80",
+			err:   nil,
+		},
+		{
+			input: "/dns4/1.2.3.4/tcp/80",
+			err:   nil,
+		},
+		{
+			input: "/dns4/1.2.3.4/tcp/80/tls",
+			err:   nil,
+		},
+		{
+			input: "/tls/dns4/1.2.3.4/tcp/80",
+			err:   errUnsupportedNetworkProtocol,
+		},
+		{
+			input: "/dns4/1.2.3.4/tls/tcp/80",
+			err:   errUnsupportedTransportProtocol,
+		},
+		{
+			input: "/dns4/1.2.3.4/tcp/80/wss",
+			err:   errUnsupportedPresentationProtocol,
+		},
+	}
+
+	for _, test := range testCases {
+		ni := constructNodeInfo(test.input)
+
+		if test.err != nil {
+			require.EqualError(t, test.err, VerifyMultiAddress(ni).Error())
+		} else {
+			require.NoError(t, VerifyMultiAddress(ni))
+		}
+	}
+}
+
+func constructNodeInfo(address string) *netmap.NodeInfo {
+	ni := new(netmap.NodeInfo)
+
+	ni.SetAddress(address)
+
+	return ni
+}