add IsPrivateIP

README.md

@@ -143,6 +143,7 @@ func IsHost(str string) bool
 func IsIP(str string) bool
 func IsIPv4(str string) bool
 func IsIPv6(str string) bool
+func IsPrivateIP(ip string) bool
 func IsISBN(str string, version int) bool
 func IsISBN10(str string) bool
 func IsISBN13(str string) bool
@@ -370,6 +371,7 @@ Here is a list of available validators for struct fields (validator - used funct
 "base64":             IsBase64,
 "datauri":            IsDataURI,
 "ip":                 IsIP,
+"ip":                 IsPrivateIP
 "port":               IsPort,
 "ipv4":               IsIPv4,
 "ipv6":               IsIPv6,

validator.go

@@ -69,6 +69,44 @@ func IsEmail(str string) bool {
 	return rxEmail.MatchString(str)
 }
 
+// private ip lists
+var aPrivateIP []*net.IPNet
+
+// IsPrivateIP check if the string is an private IP
+func IsPrivateIP(ip string) bool {
+	if 0 == len(aPrivateIP) {
+		for _, cidr := range []string{
+			"127.0.0.0/8",    // IPv4 loopback
+			"10.0.0.0/8",     // RFC1918
+			"172.16.0.0/12",  // RFC1918
+			"192.168.0.0/16", // RFC1918
+			"169.254.0.0/16", // RFC3927 link-local
+			"::1/128",        // IPv6 loopback
+			"fe80::/10",      // IPv6 link-local
+			"fc00::/7",       // IPv6 unique local addr
+		} {
+			_, block, err := net.ParseCIDR(cidr)
+			if err != nil {
+				continue
+			}
+			aPrivateIP = append(aPrivateIP, block)
+		}
+	}
+	oIp := net.ParseIP(ip)
+	if oIp == nil {
+		return false
+	}
+	if oIp.IsLoopback() || oIp.IsLinkLocalUnicast() || oIp.IsLinkLocalMulticast() || oIp.IsPrivate() {
+		return true
+	}
+	for _, s := range aPrivateIP {
+		if s.Contains(oIp) {
+			return true
+		}
+	}
+	return false
+}
+
 // IsExistingEmail checks if the string is an email of existing domain
 func IsExistingEmail(email string) bool {
 

validator_test.go

@@ -3865,3 +3865,30 @@ func TestIsE164(t *testing.T) {
 		}
 	}
 }
+
+func TestIsPrivateIP(t *testing.T) {
+	t.Parallel()
+	// Without version
+	var tests = []struct {
+		param    string
+		expected bool
+	}{
+		{"", false},
+		{"127.0.0.1", true},
+		{"127.0.2.1", true},
+		{"172.16.0.19", true},
+		{"fe80::b8:6771:9e7c:f6f1", true},
+		{"ee80::b8:6771:9e7c:f6f1", false},
+		{"fe80::1", true},
+		{"192.168.10.1", true},
+		{"::1", true},
+		{"2001:db8:0000:1:1:1:1:1", false},
+		{"300.0.0.0", false},
+	}
+	for _, test := range tests {
+		actual := IsPrivateIP(test.param)
+		if actual != test.expected {
+			t.Errorf("Expected IsPrivateIP(%q) to be %v, got %v", test.param, test.expected, actual)
+		}
+	}
+}