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package netlink
import (
"fmt"
"syscall"
"time"
"github.com/vishvananda/netlink/nl"
"github.com/vishvananda/netns"
)
// Empty handle used by the netlink package methods
var pkgHandle = &Handle{}
// Handle is an 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 deleted.
type Handle struct {
sockets map[int]*nl.SocketHandle
lookupByDump bool
}
// SupportsNetlinkFamily reports whether the passed netlink family is supported by this Handle
func (h *Handle) SupportsNetlinkFamily(nlFamily int) bool {
_, ok := h.sockets[nlFamily]
return ok
}
// NewHandle returns a netlink handle on the current network namespace.
// Caller may specify the netlink families the handle should support.
// If no families are specified, all the families the netlink package
// supports will be automatically added.
func NewHandle(nlFamilies ...int) (*Handle, error) {
return newHandle(netns.None(), netns.None(), nlFamilies...)
}
// SetSocketTimeout sets the send and receive timeout for each socket in the
// netlink handle. Although the socket timeout has granularity of one
// microsecond, the effective granularity is floored by the kernel timer tick,
// which default value is four milliseconds.
func (h *Handle) SetSocketTimeout(to time.Duration) error {
if to < time.Microsecond {
return fmt.Errorf("invalid timeout, minimul value is %s", time.Microsecond)
}
tv := syscall.NsecToTimeval(to.Nanoseconds())
for _, sh := range h.sockets {
fd := sh.Socket.GetFd()
err := syscall.SetsockoptTimeval(fd, syscall.SOL_SOCKET, syscall.SO_RCVTIMEO, &tv)
if err != nil {
return err
}
err = syscall.SetsockoptTimeval(fd, syscall.SOL_SOCKET, syscall.SO_SNDTIMEO, &tv)
if err != nil {
return err
}
}
return nil
}
// NewHandle returns a netlink handle on the network namespace
// specified by ns. If ns=netns.None(), current network namespace
// will be assumed
func NewHandleAt(ns netns.NsHandle, nlFamilies ...int) (*Handle, error) {
return newHandle(ns, netns.None(), nlFamilies...)
}
// NewHandleAtFrom works as NewHandle but allows client to specify the
// new and the origin netns Handle.
func NewHandleAtFrom(newNs, curNs netns.NsHandle) (*Handle, error) {
return newHandle(newNs, curNs)
}
func newHandle(newNs, curNs netns.NsHandle, nlFamilies ...int) (*Handle, error) {
h := &Handle{sockets: map[int]*nl.SocketHandle{}}
fams := nl.SupportedNlFamilies
if len(nlFamilies) != 0 {
fams = nlFamilies
}
for _, f := range fams {
s, err := nl.GetNetlinkSocketAt(newNs, curNs, f)
if err != nil {
return nil, err
}
h.sockets[f] = &nl.SocketHandle{Socket: s}
}
return h, nil
}
// Delete releases the resources allocated to this handle
func (h *Handle) Delete() {
for _, sh := range h.sockets {
sh.Close()
}
h.sockets = nil
}
func (h *Handle) newNetlinkRequest(proto, flags int) *nl.NetlinkRequest {
// Do this so that package API still use nl package variable nextSeqNr
if h.sockets == nil {
return nl.NewNetlinkRequest(proto, flags)
}
return &nl.NetlinkRequest{
NlMsghdr: syscall.NlMsghdr{
Len: uint32(syscall.SizeofNlMsghdr),
Type: uint16(proto),
Flags: syscall.NLM_F_REQUEST | uint16(flags),
},
Sockets: h.sockets,
}
}
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