Add an API to set RDMA subsystem network namespace mode

Add an API to change the RDMA subsystem network namespace mode as either
shared or exclusive similar to

$ rdma system set netns { shared | exclusive }

Signed-off-by: Parav Pandit <parav@mellanox.com>

nl/rdma_link_linux.go

@@ -12,6 +12,7 @@ const (
 	RDMA_NLDEV_CMD_GET     = 1
 	RDMA_NLDEV_CMD_SET     = 2
 	RDMA_NLDEV_CMD_SYS_GET = 6
+	RDMA_NLDEV_CMD_SYS_SET = 7
 )
 
 const (

rdma_link_linux.go

@@ -201,3 +201,40 @@ func (h *Handle) RdmaSystemGetNetnsMode() (string, error) {
 	}
 	return executeOneGetRdmaNetnsMode(msgs[0])
 }
+
+func netnsModeStringToUint8(mode string) (uint8, error) {
+	switch mode {
+	case "exclusive":
+		return 0, nil
+	case "shared":
+		return 1, nil
+	default:
+		return 0, fmt.Errorf("Invalid mode; %q", mode)
+	}
+}
+
+// RdmaSystemSetNetnsMode sets the net namespace mode for RDMA subsystem
+// Returns nil on success or appropriate error code.
+// Equivalent to: `rdma system set netns { shared | exclusive }'
+func RdmaSystemSetNetnsMode(NewMode string) error {
+	return pkgHandle.RdmaSystemSetNetnsMode(NewMode)
+}
+
+// RdmaSystemSetNetnsMode sets the net namespace mode for RDMA subsystem
+// Returns nil on success or appropriate error code.
+// Equivalent to: `rdma system set netns { shared | exclusive }'
+func (h *Handle) RdmaSystemSetNetnsMode(NewMode string) error {
+	value, err := netnsModeStringToUint8(NewMode)
+	if err != nil {
+		return err
+	}
+
+	proto := getProtoField(nl.RDMA_NL_NLDEV, nl.RDMA_NLDEV_CMD_SYS_SET)
+	req := h.newNetlinkRequest(proto, unix.NLM_F_ACK)
+
+	data := nl.NewRtAttr(nl.RDMA_NLDEV_SYS_ATTR_NETNS_MODE, []byte{value})
+	req.AddData(data)
+
+	_, err = req.Execute(unix.NETLINK_RDMA, 0)
+	return err
+}

rdma_link_test.go

@@ -62,3 +62,40 @@ func TestRdmaSystemGetNetnsMode(t *testing.T) {
 	}
 	t.Log("rdma system netns mode =", mode)
 }
+
+func TestRdmaSystemSetNetnsMode(t *testing.T) {
+	var newMode string
+	var mode string
+	var err error
+
+	minKernelRequired(t, 5, 2)
+	setupRdmaKModule(t, "ib_core")
+
+	mode, err = RdmaSystemGetNetnsMode()
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Log("current rdma system mode =", mode)
+
+	err = RdmaSystemSetNetnsMode(mode)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Flip the mode from current mode
+	if mode == "exclusive" {
+		err = RdmaSystemSetNetnsMode("shared")
+	} else {
+		err = RdmaSystemSetNetnsMode("exclusive")
+	}
+	newMode, err = RdmaSystemGetNetnsMode()
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Log("new rdma system mode =", newMode)
+
+	// Change back to original mode
+	err = RdmaSystemSetNetnsMode(mode)
+	if err != nil {
+		t.Fatal(err)
+	}
+}