feat(dhcp-relay): Add DHCP Relay support

Closes #413

examples/resources/routeros_ip_dhcp_relay/import.sh

@@ -0,0 +1,3 @@
+#The ID can be found via API or the terminal
+#The command for the terminal is -> :put [/ip/dhcp-relay get [print show-ids]]
+terraform import routeros_ip_dhcp_relay.relay "*0"

examples/resources/routeros_ip_dhcp_relay/resource.tf

@@ -0,0 +1,5 @@
+resource "routeros_ip_dhcp_relay" "relay" {
+    name        = "test relay"
+    interface   = "ether1"
+    dhcp_server = "0.0.0.1"
+}

routeros/provider.go

@@ -82,6 +82,7 @@ func Provider() *schema.Provider {
 			// IP objects
 			"routeros_ip_dhcp_client":                  ResourceDhcpClient(),
 			"routeros_ip_dhcp_client_option":           ResourceDhcpClientOption(),
+			"routeros_ip_dhcp_relay":                   ResourceDhcpRelay(),
 			"routeros_ip_dhcp_server":                  ResourceDhcpServer(),
 			"routeros_ip_dhcp_server_config":           ResourceDhcpServerConfig(),
 			"routeros_ip_dhcp_server_network":          ResourceDhcpServerNetwork(),

routeros/provider_schema_helpers.go

@@ -576,6 +576,10 @@ var (
 			return true
 		}
 
+		if (old == "none" && new == "") || (old == "" && new == "none") {
+			return true
+		}
+
 		if old == "" || new == "" {
 			return false
 		}

routeros/resource_ip_dhcp_relay.go

@@ -0,0 +1,66 @@
+package routeros
+
+import (
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+)
+
+// ResourceDhcpRelay https://wiki.mikrotik.com/wiki/Manual:IP/DHCP_Relay
+func ResourceDhcpRelay() *schema.Resource {
+	resSchema := map[string]*schema.Schema{
+		MetaResourcePath: PropResourcePath("/ip/dhcp-relay"),
+		MetaId:           PropId(Id),
+
+		"add_relay_info": {
+			Type:     schema.TypeBool,
+			Optional: true,
+			Description: "Adds DHCP relay agent information if enabled according to RFC 3046. Agent Circuit ID " +
+				"Sub-option contains mac address of an interface, Agent Remote ID Sub-option contains MAC address " +
+				"of the client from which request was received.",
+			DiffSuppressFunc: AlwaysPresentNotUserProvided,
+		},
+		"delay_threshold": {
+			Type:             schema.TypeString,
+			Optional:         true,
+			Description:      "If secs field in DHCP packet is smaller than delay-threshold, then this packet is ignored.",
+			DiffSuppressFunc: TimeEquall,
+		},
+		KeyDisabled: PropDisabledRw,
+		"dhcp_server": {
+			Type:        schema.TypeString,
+			Required:    true,
+			Description: "List of DHCP servers' IP addresses which should the DHCP requests be forwarded to.",
+		},
+		"interface": {
+			Type:        schema.TypeString,
+			Required:    true,
+			Description: "Interface name the DHCP relay will be working on.",
+		},
+		KeyInvalid: PropInvalidRo,
+		"local_address": {
+			Type:     schema.TypeString,
+			Optional: true,
+			Description: "The unique IP address of this DHCP relay needed for DHCP server to distinguish relays. " +
+				"If set to 0.0.0.0 - the IP address will be chosen automatically",
+			DiffSuppressFunc: AlwaysPresentNotUserProvided,
+		},
+		KeyName: PropName("Descriptive name for the relay."),
+		"relay_info_remote_id": {
+			Type:     schema.TypeString,
+			Optional: true,
+			Description: "Specified string will be used to construct Option 82 instead of client's MAC address. Option " +
+				"82 consist of: interface from which packets was received + client mac address or relay-info-remote-id",
+			DiffSuppressFunc: AlwaysPresentNotUserProvided,
+		},
+	}
+	return &schema.Resource{
+		CreateContext: DefaultCreate(resSchema),
+		ReadContext:   DefaultRead(resSchema),
+		UpdateContext: DefaultUpdate(resSchema),
+		DeleteContext: DefaultDelete(resSchema),
+		Importer: &schema.ResourceImporter{
+			StateContext: schema.ImportStatePassthroughContext,
+		},
+
+		Schema: resSchema,
+	}
+}

routeros/resource_ip_dhcp_relay_test.go

@@ -0,0 +1,48 @@
+package routeros
+
+import (
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+)
+
+const testIpDhcpRelayAddress = "routeros_ip_dhcp_relay.test"
+
+func TestAccIpDhcpRelayTest_basic(t *testing.T) {
+	for _, name := range testNames {
+		t.Run(name, func(t *testing.T) {
+			resource.Test(t, resource.TestCase{
+				PreCheck: func() {
+					testAccPreCheck(t)
+					testSetTransportEnv(t, name)
+				},
+				ProviderFactories: testAccProviderFactories,
+				CheckDestroy:      testCheckResourceDestroy("/ip/dhcp-relay", "routeros_ip_dhcp_relay"),
+				Steps: []resource.TestStep{
+					{
+						Config: testAccIpDhcpRelayConfig(),
+						Check: resource.ComposeTestCheckFunc(
+							testResourcePrimaryInstanceId(testIpDhcpRelayAddress),
+							resource.TestCheckResourceAttr(testIpDhcpRelayAddress, "name", "test relay"),
+							resource.TestCheckResourceAttr(testIpDhcpRelayAddress, "interface", "ether1"),
+							resource.TestCheckResourceAttr(testIpDhcpRelayAddress, "dhcp_server", "0.0.0.1"),
+						),
+					},
+				},
+			})
+
+		})
+	}
+}
+
+func testAccIpDhcpRelayConfig() string {
+	return providerConfig + `
+
+resource "routeros_ip_dhcp_relay" "test" {
+	name        = "test relay"
+	interface   = "ether1"
+	dhcp_server = "0.0.0.1"
+  }
+
+`
+}