feat: option to disable VF polling

Introduces a configuration flag to disable Virtual Function polling,
providing users with control over polling behavior for performance
optimization scenarios.

Fixes: #1097

Signed-off-by: pasteley <ceasebeing@gmail.com>

handle_linux.go

@@ -12,13 +12,24 @@ import (
 // Empty handle used by the netlink package methods
 var pkgHandle = &Handle{}
 
-// Handle is an handle for the netlink requests on a
+type HandleOptions struct {
+	lookupByDump  bool
+	collectVFInfo bool
+}
+
+// Handle is a handle for the netlink requests on a
 // specific network namespace. All the requests on the
 // same netlink family share the same netlink socket,
 // which gets released when the handle is Close'd.
 type Handle struct {
 	sockets map[int]*nl.SocketHandle
-	lookupByDump bool
+	options HandleOptions
+}
+
+// DisableVFInfoCollection configures the handle to skip VF information fetching
+func (h *Handle) DisableVFInfoCollection() *Handle {
+	h.options.collectVFInfo = false
+	return h
 }
 
 // SetSocketTimeout configures timeout for default netlink sockets
@@ -136,7 +147,10 @@ func NewHandleAtFrom(newNs, curNs netns.NsHandle) (*Handle, error) {
 }
 
 func newHandle(newNs, curNs netns.NsHandle, nlFamilies ...int) (*Handle, error) {
-	h := &Handle{sockets: map[int]*nl.SocketHandle{}}
+	h := &Handle{
+		sockets: map[int]*nl.SocketHandle{},
+		options: HandleOptions{collectVFInfo: true},
+	}
 	fams := nl.SupportedNlFamilies
 	if len(nlFamilies) != 0 {
 		fams = nlFamilies

link_linux.go

@@ -1933,7 +1933,7 @@ func LinkByName(name string) (Link, error) {
 // filtering a dump of all link names. In this case, if the returned error is
 // [ErrDumpInterrupted] the result may be missing or outdated.
 func (h *Handle) LinkByName(name string) (Link, error) {
-	if h.lookupByDump {
+	if h.options.lookupByDump {
 		return h.linkByNameDump(name)
 	}
 
@@ -1942,8 +1942,10 @@ func (h *Handle) LinkByName(name string) (Link, error) {
 	msg := nl.NewIfInfomsg(unix.AF_UNSPEC)
 	req.AddData(msg)
 
+	if h.options.collectVFInfo {
 		attr := nl.NewRtAttr(unix.IFLA_EXT_MASK, nl.Uint32Attr(nl.RTEXT_FILTER_VF))
 		req.AddData(attr)
+	}
 
 	nameData := nl.NewRtAttr(unix.IFLA_IFNAME, nl.ZeroTerminated(name))
 	if len(name) > 15 {
@@ -1955,7 +1957,7 @@ func (h *Handle) LinkByName(name string) (Link, error) {
 	if err == unix.EINVAL {
 		// older kernels don't support looking up via IFLA_IFNAME
 		// so fall back to dumping all links
-		h.lookupByDump = true
+		h.options.lookupByDump = true
 		return h.linkByNameDump(name)
 	}
 
@@ -1979,7 +1981,7 @@ func LinkByAlias(alias string) (Link, error) {
 // filtering a dump of all link names. In this case, if the returned error is
 // [ErrDumpInterrupted] the result may be missing or outdated.
 func (h *Handle) LinkByAlias(alias string) (Link, error) {
-	if h.lookupByDump {
+	if h.options.lookupByDump {
 		return h.linkByAliasDump(alias)
 	}
 
@@ -1988,8 +1990,10 @@ func (h *Handle) LinkByAlias(alias string) (Link, error) {
 	msg := nl.NewIfInfomsg(unix.AF_UNSPEC)
 	req.AddData(msg)
 
+	if h.options.collectVFInfo {
 		attr := nl.NewRtAttr(unix.IFLA_EXT_MASK, nl.Uint32Attr(nl.RTEXT_FILTER_VF))
 		req.AddData(attr)
+	}
 
 	nameData := nl.NewRtAttr(unix.IFLA_IFALIAS, nl.ZeroTerminated(alias))
 	req.AddData(nameData)
@@ -1998,7 +2002,7 @@ func (h *Handle) LinkByAlias(alias string) (Link, error) {
 	if err == unix.EINVAL {
 		// older kernels don't support looking up via IFLA_IFALIAS
 		// so fall back to dumping all links
-		h.lookupByDump = true
+		h.options.lookupByDump = true
 		return h.linkByAliasDump(alias)
 	}
 
@@ -2017,8 +2021,10 @@ func (h *Handle) LinkByIndex(index int) (Link, error) {
 	msg := nl.NewIfInfomsg(unix.AF_UNSPEC)
 	msg.Index = int32(index)
 	req.AddData(msg)
+	if h.options.collectVFInfo {
 		attr := nl.NewRtAttr(unix.IFLA_EXT_MASK, nl.Uint32Attr(nl.RTEXT_FILTER_VF))
 		req.AddData(attr)
+	}
 
 	return execGetLink(req)
 }