ipam;remote-vlan-nse fix; Singlepoint IPAM should not allocate broadc…

…ast address

Signed-off-by: Laszlo Kiraly <laszlo.kiraly@est.tech>

pkg/networkservice/ipam/singlepointipam/README.md

@@ -0,0 +1,7 @@
+# Single point IPAM
+
+This chain element is used to provide IPAM functionality for the nse-remote-vlan.
+
+Per request allocates a single IP address in the given subnet and provides static routes. Request can set some exclude IP prefixes for the allocated IP.
+
+The first IP address from the specified IP range and the broadcast IPv4 address will be witheld.

pkg/networkservice/ipam/singlepointipam/server.go

@@ -32,6 +32,7 @@ import (
 	"github.com/networkservicemesh/api/pkg/api/networkservice"
 
 	"github.com/networkservicemesh/sdk/pkg/networkservice/core/next"
+	"github.com/networkservicemesh/sdk/pkg/tools/cidr"
 	"github.com/networkservicemesh/sdk/pkg/tools/ippool"
 )
 
@@ -78,6 +79,13 @@ func (sipam *singlePIpam) init() {
 		mask := fmt.Sprintf("/%d", ones)
 		sipam.masks = append(sipam.masks, mask)
 		ipPool := ippool.NewWithNet(prefix)
+		if prefix.IP.To4() != nil {
+			// Remove the broadcast address from the pool
+			_, sipam.initErr = ipPool.PullIP(cidr.BroadcastAddress(prefix))
+			if sipam.initErr != nil {
+				return
+			}
+		}
 		sipam.ipPools = append(sipam.ipPools, ipPool)
 	}
 }

pkg/networkservice/ipam/singlepointipam/server_test.go

@@ -1,5 +1,5 @@
 // Copyright (c) 2020-2021 Doc.ai and/or its affiliates.
-// Copyright (c) 2020-2022 Nordix and its affiliates.
+// Copyright (c) 2020-2023 Nordix and its affiliates.
 //
 // SPDX-License-Identifier: Apache-2.0
 //
@@ -201,6 +201,34 @@ func TestExclude128PrefixIPv6(t *testing.T) {
 	validateConn(t, conn3, "fe80::1:6/112")
 }
 
+func TestBroadCastIP(t *testing.T) {
+	_, ipNet, err := net.ParseCIDR("10.143.248.96/28")
+	require.NoError(t, err)
+
+	srv := newIpamServer(ipNet)
+
+	conn1, err := srv.Request(context.Background(), newRequest())
+	require.NoError(t, err)
+	validateConn(t, conn1, "10.143.248.97/28")
+
+	conn2, err := srv.Request(context.Background(), newRequest())
+	require.NoError(t, err)
+	validateConn(t, conn2, "10.143.248.98/28")
+
+	for i := 0; i < 11; i++ {
+		_, err = srv.Request(context.Background(), newRequest())
+		require.NoError(t, err)
+	}
+
+	conn3, err := srv.Request(context.Background(), newRequest())
+	require.NoError(t, err)
+	validateConn(t, conn3, "10.143.248.110/28")
+
+	// Broadcast
+	_, err = srv.Request(context.Background(), newRequest())
+	require.NoError(t, err)
+}
+
 func TestOutOfIPs(t *testing.T) {
 	_, ipNet, err := net.ParseCIDR("192.168.1.2/31")
 	require.NoError(t, err)