netdev: add queue-get and queue-create with queue leasing

netdev_linux.go

@@ -0,0 +1,275 @@
+package netlink
+
+import (
+	"errors"
+	"fmt"
+	"syscall"
+
+	"github.com/vishvananda/netlink/nl"
+	"golang.org/x/sys/unix"
+)
+
+// NetDevQueueType identifies the direction of a netdev queue.
+type NetDevQueueType uint32
+
+const (
+	NetDevQueueTypeRx NetDevQueueType = nl.NETDEV_QUEUE_TYPE_RX
+	NetDevQueueTypeTx NetDevQueueType = nl.NETDEV_QUEUE_TYPE_TX
+)
+
+// NetDevQueueID identifies a single queue on a netdevice by its id and type.
+type NetDevQueueID struct {
+	ID   uint32
+	Type NetDevQueueType
+}
+
+// NetDevQueueLease identifies the peer endpoint of a queue lease. Its direction
+// depends on where it is used: in [NetDevQueueCreateRequest] it names the
+// physical queue to lease from, while in a [NetDevQueue] returned by
+// [NetDevQueueGet] it names the virtual queue leasing the queried physical
+// queue.
+type NetDevQueueLease struct {
+	// IfIndex identifies the peer netdevice.
+	IfIndex uint32
+	// Queue identifies the peer queue on that netdevice.
+	Queue NetDevQueueID
+	// NetNSID is the network namespace id of the peer device, relative to the
+	// caller's namespace. NetNSIDSet reports whether it was provided.
+	NetNSID    int32
+	NetNSIDSet bool
+}
+
+// NetDevQueue is a queue on a netdevice as reported by queue-get.
+type NetDevQueue struct {
+	IfIndex uint32
+	ID      uint32
+	Type    NetDevQueueType
+	NapiID  uint32
+	// Lease is non-nil when this physical queue is leased by a virtual queue.
+	// It identifies that virtual queue, not the physical queue queried here.
+	Lease *NetDevQueueLease
+}
+
+// netdevRequest builds and executes a request against the "netdev" generic
+// netlink family, returning the attribute lists of each response message.
+func (h *Handle) netdevRequest(command uint8, flags int, attrs []*nl.RtAttr) ([][]syscall.NetlinkRouteAttr, error) {
+	f, err := h.GenlFamilyGet(nl.NETDEV_FAMILY_NAME)
+	if err != nil {
+		return nil, err
+	}
+	req := h.newNetlinkRequest(int(f.ID), flags)
+	req.AddData(&nl.Genlmsg{
+		Command: command,
+		Version: nl.NETDEV_FAMILY_VERSION,
+	})
+	for _, a := range attrs {
+		req.AddData(a)
+	}
+
+	msgs, executeErr := req.Execute(unix.NETLINK_GENERIC, 0)
+	if executeErr != nil && !errors.Is(executeErr, ErrDumpInterrupted) {
+		return nil, executeErr
+	}
+	out := make([][]syscall.NetlinkRouteAttr, 0, len(msgs))
+	for _, m := range msgs {
+		parsed, err := nl.ParseRouteAttr(m[nl.SizeofGenlmsg:])
+		if err != nil {
+			return nil, err
+		}
+		out = append(out, parsed)
+	}
+	return out, executeErr
+}
+
+func readNetDevUint32(a syscall.NetlinkRouteAttr) (uint32, error) {
+	if len(a.Value) < 4 {
+		return 0, fmt.Errorf("netlink: attribute %d too short: got %d bytes, want 4", a.Attr.Type&nl.NLA_TYPE_MASK, len(a.Value))
+	}
+	return native.Uint32(a.Value), nil
+}
+
+// parseNetDevQueueID decodes a queue-id nested attribute (NETDEV_A_QUEUE_ID
+// and NETDEV_A_QUEUE_TYPE) into a NetDevQueueID.
+func parseNetDevQueueID(value []byte) (NetDevQueueID, error) {
+	var q NetDevQueueID
+	attrs, err := nl.ParseRouteAttr(value)
+	if err != nil {
+		return q, err
+	}
+	for _, a := range attrs {
+		switch a.Attr.Type & nl.NLA_TYPE_MASK {
+		case nl.NETDEV_A_QUEUE_ID:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return q, err
+			}
+			q.ID = v
+		case nl.NETDEV_A_QUEUE_TYPE:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return q, err
+			}
+			q.Type = NetDevQueueType(v)
+		}
+	}
+	return q, nil
+}
+
+// parseNetDevQueueLease decodes a lease nested attribute (the peer ifindex,
+// nested queue-id, and optional netns-id) into a NetDevQueueLease.
+func parseNetDevQueueLease(value []byte) (*NetDevQueueLease, error) {
+	attrs, err := nl.ParseRouteAttr(value)
+	if err != nil {
+		return nil, err
+	}
+	lease := &NetDevQueueLease{}
+	for _, a := range attrs {
+		switch a.Attr.Type & nl.NLA_TYPE_MASK {
+		case nl.NETDEV_A_LEASE_IFINDEX:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return nil, err
+			}
+			lease.IfIndex = v
+		case nl.NETDEV_A_LEASE_QUEUE:
+			q, err := parseNetDevQueueID(a.Value)
+			if err != nil {
+				return nil, err
+			}
+			lease.Queue = q
+		case nl.NETDEV_A_LEASE_NETNS_ID:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return nil, err
+			}
+			lease.NetNSID = int32(v)
+			lease.NetNSIDSet = true
+		}
+	}
+	return lease, nil
+}
+
+// parseNetDevQueue decodes the attributes of a queue-get response into a
+// NetDevQueue, including its nested lease attribute when present.
+func parseNetDevQueue(attrs []syscall.NetlinkRouteAttr) (*NetDevQueue, error) {
+	q := &NetDevQueue{}
+	for _, a := range attrs {
+		switch a.Attr.Type & nl.NLA_TYPE_MASK {
+		case nl.NETDEV_A_QUEUE_IFINDEX:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return nil, err
+			}
+			q.IfIndex = v
+		case nl.NETDEV_A_QUEUE_ID:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return nil, err
+			}
+			q.ID = v
+		case nl.NETDEV_A_QUEUE_TYPE:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return nil, err
+			}
+			q.Type = NetDevQueueType(v)
+		case nl.NETDEV_A_QUEUE_NAPI_ID:
+			v, err := readNetDevUint32(a)
+			if err != nil {
+				return nil, err
+			}
+			q.NapiID = v
+		case nl.NETDEV_A_QUEUE_LEASE:
+			lease, err := parseNetDevQueueLease(a.Value)
+			if err != nil {
+				return nil, err
+			}
+			q.Lease = lease
+		}
+	}
+	return q, nil
+}
+
+// NetDevQueueGet returns information about a single queue on the netdevice
+// identified by ifIndex, including its lease binding if it has one.
+// Equivalent to: `ynl --do queue-get --json '{"ifindex":.., "id":.., "type":..}'`
+func NetDevQueueGet(ifIndex int, id uint32, qType NetDevQueueType) (*NetDevQueue, error) {
+	return pkgHandle.NetDevQueueGet(ifIndex, id, qType)
+}
+
+// NetDevQueueGet returns information about a single queue. See [NetDevQueueGet].
+func (h *Handle) NetDevQueueGet(ifIndex int, id uint32, qType NetDevQueueType) (*NetDevQueue, error) {
+	attrs := []*nl.RtAttr{
+		nl.NewRtAttr(nl.NETDEV_A_QUEUE_IFINDEX, nl.Uint32Attr(uint32(ifIndex))),
+		nl.NewRtAttr(nl.NETDEV_A_QUEUE_ID, nl.Uint32Attr(id)),
+		nl.NewRtAttr(nl.NETDEV_A_QUEUE_TYPE, nl.Uint32Attr(uint32(qType))),
+	}
+	msgs, err := h.netdevRequest(nl.NETDEV_CMD_QUEUE_GET, unix.NLM_F_ACK, attrs)
+	if err != nil {
+		return nil, err
+	}
+	if len(msgs) == 0 {
+		return nil, fmt.Errorf("netlink: no response for queue-get")
+	}
+	return parseNetDevQueue(msgs[0])
+}
+
+// NetDevQueueCreateRequest describes a queue-create operation that creates a
+// new rx queue on a virtual netdevice and leases it to a real queue on a
+// physical netdevice.
+type NetDevQueueCreateRequest struct {
+	// IfIndex is the virtual netdevice on which to create the new queue.
+	IfIndex int
+	// Type is the queue type. Only rx queues may be leased today.
+	Type NetDevQueueType
+	// Lease names the physical device and real queue to lease.
+	Lease NetDevQueueLease
+}
+
+// NetDevQueueCreate creates a new queue on a virtual netdevice and leases it to
+// a real queue on a physical netdevice, returning the new queue's id. Requires
+// CAP_NET_ADMIN.
+// Equivalent to: `ynl --do queue-create --json
+// '{"ifindex":.., "type":"rx", "lease":{"ifindex":.., "queue":{"id":.., "type":"rx"}}}'`
+func NetDevQueueCreate(req NetDevQueueCreateRequest) (uint32, error) {
+	return pkgHandle.NetDevQueueCreate(req)
+}
+
+// NetDevQueueCreate creates and leases a queue. See [NetDevQueueCreate].
+func (h *Handle) NetDevQueueCreate(req NetDevQueueCreateRequest) (uint32, error) {
+	if req.Lease.NetNSIDSet && req.Lease.NetNSID < 0 {
+		return 0, fmt.Errorf("netlink: lease netns id must be non-negative, got %d", req.Lease.NetNSID)
+	}
+
+	// Build the nested lease attribute. Container attributes must carry the
+	// NLA_F_NESTED flag: the kernel's nla_parse_nested rejects them otherwise
+	// ("NLA_F_NESTED is missing").
+	lease := nl.NewRtAttr(unix.NLA_F_NESTED|nl.NETDEV_A_QUEUE_LEASE, nil)
+	lease.AddRtAttr(nl.NETDEV_A_LEASE_IFINDEX, nl.Uint32Attr(req.Lease.IfIndex))
+	if req.Lease.NetNSIDSet {
+		lease.AddRtAttr(nl.NETDEV_A_LEASE_NETNS_ID, nl.Uint32Attr(uint32(req.Lease.NetNSID)))
+	}
+	queue := lease.AddRtAttr(unix.NLA_F_NESTED|nl.NETDEV_A_LEASE_QUEUE, nil)
+	queue.AddRtAttr(nl.NETDEV_A_QUEUE_ID, nl.Uint32Attr(req.Lease.Queue.ID))
+	queue.AddRtAttr(nl.NETDEV_A_QUEUE_TYPE, nl.Uint32Attr(uint32(req.Lease.Queue.Type)))
+
+	attrs := []*nl.RtAttr{
+		nl.NewRtAttr(nl.NETDEV_A_QUEUE_IFINDEX, nl.Uint32Attr(uint32(req.IfIndex))),
+		nl.NewRtAttr(nl.NETDEV_A_QUEUE_TYPE, nl.Uint32Attr(uint32(req.Type))),
+		lease,
+	}
+
+	msgs, err := h.netdevRequest(nl.NETDEV_CMD_QUEUE_CREATE, unix.NLM_F_ACK, attrs)
+	if err != nil {
+		return 0, err
+	}
+	if len(msgs) == 0 {
+		return 0, fmt.Errorf("netlink: no response for queue-create")
+	}
+	for _, a := range msgs[0] {
+		if a.Attr.Type&nl.NLA_TYPE_MASK == nl.NETDEV_A_QUEUE_ID {
+			return readNetDevUint32(a)
+		}
+	}
+	return 0, fmt.Errorf("netlink: queue-create reply missing queue id")
+}