Add Driver Interface for Enhanced Data Encoding

This commit implements significant changes by introducing a Driver interface, fundamentally altering the LinkInfo struct. The Data and SlaveData fields are replaced in a non-backward-compatible manner to support driver-specific data encoding. This update addresses the previous limitation where these fields were only byte slices, lacking the capability for detailed data encoding. LinkNetkit is implemented as a Driver interface. During the decoding process, data identified as "netkit" is now explicitly converted into a LinkNetkit struct. Conversely, data not matching recognized types is assigned to a LinkUndefined struct. Important: This update introduces breaking changes and will require a major version update of the library. Signed-off-by: Birol Bilgin <[email protected]>
brlbil · Apr 3, 2024 · 7e4eabe · 7e4eabe
1 parent e96eaa2
commit 7e4eabe
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Showing 5 changed files with 157 additions and 11 deletions.
diff --git a/internal/unix/types_linux.go b/internal/unix/types_linux.go
@@ -71,6 +71,12 @@ const (
 	IFLA_INFO_SLAVE_KIND        = linux.IFLA_INFO_SLAVE_KIND
 	IFLA_INFO_DATA              = linux.IFLA_INFO_DATA
 	IFLA_INFO_SLAVE_DATA        = linux.IFLA_INFO_SLAVE_DATA
+	IFLA_NETKIT_UNSPEC          = linux.IFLA_NETKIT_UNSPEC
+	IFLA_NETKIT_PEER_INFO       = linux.IFLA_NETKIT_PEER_INFO
+	IFLA_NETKIT_PRIMARY         = linux.IFLA_NETKIT_PRIMARY
+	IFLA_NETKIT_POLICY          = linux.IFLA_NETKIT_POLICY
+	IFLA_NETKIT_PEER_POLICY     = linux.IFLA_NETKIT_PEER_POLICY
+	IFLA_NETKIT_MODE            = linux.IFLA_NETKIT_MODE
 	IFLA_XDP                    = linux.IFLA_XDP
 	IFLA_XDP_FD                 = linux.IFLA_XDP_FD
 	IFLA_XDP_ATTACHED           = linux.IFLA_XDP_ATTACHED
@@ -147,4 +153,10 @@ const (
 	FRA_IP_PROTO                = linux.FRA_IP_PROTO
 	FRA_SPORT_RANGE             = linux.FRA_SPORT_RANGE
 	FRA_DPORT_RANGE             = linux.FRA_DPORT_RANGE
+	NETKIT_NEXT                 = linux.NETKIT_NEXT
+	NETKIT_PASS                 = linux.NETKIT_PASS
+	NETKIT_DROP                 = linux.NETKIT_DROP
+	NETKIT_REDIRECT             = linux.NETKIT_REDIRECT
+	NETKIT_L2                   = linux.NETKIT_L2
+	NETKIT_L3                   = linux.NETKIT_L3
 )
diff --git a/internal/unix/types_other.go b/internal/unix/types_other.go
@@ -67,6 +67,12 @@ const (
 	IFLA_INFO_SLAVE_KIND        = 0x4
 	IFLA_INFO_DATA              = 0x2
 	IFLA_INFO_SLAVE_DATA        = 0x5
+	IFLA_NETKIT_UNSPEC          = 0x0
+	IFLA_NETKIT_PEER_INFO       = 0x1
+	IFLA_NETKIT_PRIMARY         = 0x2
+	IFLA_NETKIT_POLICY          = 0x3
+	IFLA_NETKIT_PEER_POLICY     = 0x4
+	IFLA_NETKIT_MODE            = 0x5
 	IFLA_XDP                    = 0x2b
 	IFLA_XDP_FD                 = 0x1
 	IFLA_XDP_ATTACHED           = 0x2
@@ -143,4 +149,10 @@ const (
 	FRA_IP_PROTO                = 0x16
 	FRA_SPORT_RANGE             = 0x17
 	FRA_DPORT_RANGE             = 0x18
+	NETKIT_NEXT                 = -0x1
+	NETKIT_PASS                 = 0x0
+	NETKIT_DROP                 = 0x2
+	NETKIT_REDIRECT             = 0x7
+	NETKIT_L2                   = 0x0
+	NETKIT_L3                   = 0x1
 )
diff --git a/link.go b/link.go
@@ -550,9 +550,9 @@ func (a *LinkStats64) unmarshalBinary(b []byte) error {
 // LinkInfo contains data for specific network types
 type LinkInfo struct {
 	Kind      string // Driver name
-	Data      []byte // Driver specific configuration stored as nested Netlink messages
+	Data      Driver // Driver specific configuration stored as nested Netlink messages
 	SlaveKind string // Slave driver name
-	SlaveData []byte // Slave driver specific configuration
+	SlaveData Driver // Slave driver specific configuration
 }
 
 func (i *LinkInfo) decode(ad *netlink.AttributeDecoder) error {
@@ -563,9 +563,19 @@ func (i *LinkInfo) decode(ad *netlink.AttributeDecoder) error {
 		case unix.IFLA_INFO_SLAVE_KIND:
 			i.SlaveKind = ad.String()
 		case unix.IFLA_INFO_DATA:
-			i.Data = ad.Bytes()
+			i.Data = getDriver(i.Kind)
+			if lu, ok := i.Data.(*LinkData); ok {
+				lu.Data = ad.Bytes()
+			} else {
+				ad.Nested(i.Data.decode)
+			}
 		case unix.IFLA_INFO_SLAVE_DATA:
-			i.SlaveData = ad.Bytes()
+			i.SlaveData = getDriver(i.SlaveKind)
+			if lu, ok := i.SlaveData.(*LinkData); ok {
+				lu.Data = ad.Bytes()
+			} else {
+				ad.Nested(i.SlaveData.decode)
+			}
 		}
 	}
 
@@ -574,11 +584,35 @@ func (i *LinkInfo) decode(ad *netlink.AttributeDecoder) error {
 
 func (i *LinkInfo) encode(ae *netlink.AttributeEncoder) error {
 	ae.String(unix.IFLA_INFO_KIND, i.Kind)
-	ae.Bytes(unix.IFLA_INFO_DATA, i.Data)
+	if i.Data != nil {
+		if lu, ok := i.Data.(*LinkData); ok {
+			ae.Bytes(unix.IFLA_INFO_DATA, lu.Data)
+		} else {
+			ae.Do(unix.IFLA_INFO_DATA, func() ([]byte, error) {
+				nae := netlink.NewAttributeEncoder()
+				nae.ByteOrder = ae.ByteOrder
+				if err := i.encode(nae); err != nil {
+					return nil, err
+				}
+				return nae.Encode()
+			})
+		}
+	}
 
-	if len(i.SlaveData) > 0 {
+	if i.SlaveData != nil {
 		ae.String(unix.IFLA_INFO_SLAVE_KIND, i.SlaveKind)
-		ae.Bytes(unix.IFLA_INFO_SLAVE_DATA, i.SlaveData)
+		if lu, ok := i.Data.(*LinkData); ok {
+			ae.Bytes(unix.IFLA_INFO_SLAVE_DATA, lu.Data)
+		} else {
+			ae.Do(unix.IFLA_INFO_SLAVE_DATA, func() ([]byte, error) {
+				nae := netlink.NewAttributeEncoder()
+				nae.ByteOrder = ae.ByteOrder
+				if err := i.SlaveData.encode(nae); err != nil {
+					return nil, err
+				}
+				return nae.Encode()
+			})
+		}
 	}
 
 	return nil

diff --git a/link_driver.go b/link_driver.go
@@ -0,0 +1,88 @@
+package rtnetlink
+
+import (
+	"github.com/jsimonetti/rtnetlink/internal/unix"
+	"github.com/mdlayher/netlink"
+)
+
+type Driver interface {
+	encode(*netlink.AttributeEncoder) error
+	decode(*netlink.AttributeDecoder) error
+	rtDriver()
+}
+
+func getDriver(kind string) Driver {
+	switch kind {
+	case "netkit":
+		return &LinkNetkit{}
+	default:
+		return &LinkData{}
+	}
+}
+
+// LinkNetkit holds netkit link specific information
+type LinkNetkit struct {
+	Mode       uint32
+	Policy     int32
+	PeerPolicy int32
+	Primary    bool
+	PeerInfo   *LinkMessage
+}
+
+var _ Driver = &LinkNetkit{}
+
+func (n *LinkNetkit) decode(ad *netlink.AttributeDecoder) error {
+	for ad.Next() {
+		switch ad.Type() {
+		case unix.IFLA_NETKIT_MODE:
+			n.Mode = ad.Uint32()
+		case unix.IFLA_NETKIT_POLICY:
+			n.Policy = ad.Int32()
+		case unix.IFLA_NETKIT_PEER_POLICY:
+			n.PeerPolicy = ad.Int32()
+		case unix.IFLA_NETKIT_PRIMARY:
+			n.Primary = ad.Uint8() != 0
+		}
+	}
+	return nil
+}
+
+func (n *LinkNetkit) encode(ae *netlink.AttributeEncoder) error {
+	ae.Uint32(unix.IFLA_NETKIT_MODE, n.Mode)
+	ae.Int32(unix.IFLA_NETKIT_POLICY, n.Policy)
+	ae.Int32(unix.IFLA_NETKIT_PEER_POLICY, n.PeerPolicy)
+	if n.PeerInfo != nil {
+		n.PeerInfo.Family = unix.AF_UNSPEC
+		// we need to set the netkit.peerInfo.Flags and .Change according to primary link
+		// however we do not have this information here
+		b, err := n.PeerInfo.MarshalBinary()
+		if err != nil {
+			return err
+		}
+		ae.Bytes(unix.IFLA_NETKIT_PEER_INFO, b)
+	}
+	return nil
+}
+
+// rtDriver is an empty method to sattisfy the Driver interface.
+func (n *LinkNetkit) rtDriver() {}
+
+// LinkData is retured when the Driver kind for the LinkInfo Data is not defined
+type LinkData struct {
+	Data []byte
+}
+
+var _ Driver = &LinkData{}
+
+// dencode is an empty method to sattisfy the Driver interface.
+func (u *LinkData) decode(ad *netlink.AttributeDecoder) error {
+	return nil
+}
+
+// encode is an empty method to sattisfy the Driver interface.
+func (u *LinkData) encode(ae *netlink.AttributeEncoder) error {
+	return nil
+}
+
+// rtDriver is an empty method to sattisfy the Driver interface.
+func (u *LinkData) rtDriver() {}
diff --git a/link_test.go b/link_test.go
@@ -105,9 +105,9 @@ func TestLinkMessageMarshalBinary(t *testing.T) {
 					Name:      "lo",
 					Info: &LinkInfo{
 						Kind:      "data",
-						Data:      []byte{1, 2, 3, 4, 5, 6, 7, 8, 9},
+						Data:      &LinkData{Data: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9}},
 						SlaveKind: "foo",
-						SlaveData: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9},
+						SlaveData: &LinkData{Data: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9}},
 					},
 				},
 			},
@@ -371,9 +371,9 @@ func TestLinkMessageUnmarshalBinary(t *testing.T) {
 					Name:      "lo",
 					Info: &LinkInfo{
 						Kind:      "data",
-						Data:      []byte{1, 2, 3, 4, 5, 6, 7, 8, 9},
+						Data:      &LinkData{Data: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9}},
 						SlaveKind: "foo",
-						SlaveData: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9},
+						SlaveData: &LinkData{Data: []byte{1, 2, 3, 4, 5, 6, 7, 8, 9}},
 					},
 				},
 			},