// deserializeRoute decodes a binary netlink message into a Route struct
func deserializeRoute(m []byte) (Route, error) {
route := Route{}
msg := nl.DeserializeRtMsg(m)
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return route, err
}
route.Scope = Scope(msg.Scope)
native := nl.NativeEndian()
for _, attr := range attrs {
switch attr.Attr.Type {
case syscall.RTA_GATEWAY:
route.Gw = net.IP(attr.Value)
case syscall.RTA_PREFSRC:
route.Src = net.IP(attr.Value)
case syscall.RTA_DST:
route.Dst = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)),
}
case syscall.RTA_OIF:
routeIndex := int(native.Uint32(attr.Value[0:4]))
route.LinkIndex = routeIndex
}
}
return route, nil
}
// RouteGet gets a route to a specific destination from the host system.
// Equivalent to: 'ip route get'.
func RouteGet(destination net.IP) ([]Route, error) {
req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_REQUEST)
family := nl.GetIPFamily(destination)
var destinationData []byte
var bitlen uint8
if family == FAMILY_V4 {
destinationData = destination.To4()
bitlen = 32
} else {
destinationData = destination.To16()
bitlen = 128
}
msg := &nl.RtMsg{}
msg.Family = uint8(family)
msg.Dst_len = bitlen
req.AddData(msg)
rtaDst := nl.NewRtAttr(syscall.RTA_DST, destinationData)
req.AddData(rtaDst)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
if err != nil {
return nil, err
}
native := nl.NativeEndian()
res := make([]Route, 0)
for _, m := range msgs {
msg := nl.DeserializeRtMsg(m)
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
route := Route{}
for _, attr := range attrs {
switch attr.Attr.Type {
case syscall.RTA_GATEWAY:
route.Gw = net.IP(attr.Value)
case syscall.RTA_PREFSRC:
route.Src = net.IP(attr.Value)
case syscall.RTA_DST:
route.Dst = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)),
}
case syscall.RTA_OIF:
routeIndex := int(native.Uint32(attr.Value[0:4]))
route.LinkIndex = routeIndex
}
}
res = append(res, route)
}
return res, nil
}
// RouteList gets a list of routes in the system.
// Equivalent to: `ip route show`.
// The list can be filtered by link and ip family.
func RouteList(link Link, family int) ([]Route, error) {
req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_DUMP)
msg := nl.NewIfInfomsg(family)
req.AddData(msg)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
if err != nil {
return nil, err
}
index := 0
if link != nil {
base := link.Attrs()
ensureIndex(base)
index = base.Index
}
var res []Route
for _, m := range msgs {
msg := nl.DeserializeRtMsg(m)
if msg.Flags&syscall.RTM_F_CLONED != 0 {
// Ignore cloned routes
continue
}
if msg.Table != syscall.RT_TABLE_MAIN {
// Ignore non-main tables
continue
}
route, err := deserializeRoute(m)
if err != nil {
return nil, err
}
if link != nil && route.LinkIndex != index {
// Ignore routes from other interfaces
continue
}
res = append(res, route)
}
return res, nil
}
// RouteList gets a list of routes in the system.
// Equivalent to: `ip route show`.
// The list can be filtered by link and ip family.
func RouteList(link Link, family int) ([]Route, error) {
req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_DUMP)
msg := nl.NewIfInfomsg(family)
req.AddData(msg)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
if err != nil {
return nil, err
}
index := 0
if link != nil {
base := link.Attrs()
ensureIndex(base)
index = base.Index
}
native := nl.NativeEndian()
res := make([]Route, 0)
for _, m := range msgs {
msg := nl.DeserializeRtMsg(m)
if msg.Flags&syscall.RTM_F_CLONED != 0 {
// Ignore cloned routes
continue
}
if msg.Table != syscall.RT_TABLE_MAIN {
// Ignore non-main tables
continue
}
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return nil, err
}
route := Route{Scope: Scope(msg.Scope)}
for _, attr := range attrs {
switch attr.Attr.Type {
case syscall.RTA_GATEWAY:
route.Gw = net.IP(attr.Value)
case syscall.RTA_PREFSRC:
route.Src = net.IP(attr.Value)
case syscall.RTA_DST:
route.Dst = &net.IPNet{
IP: attr.Value,
Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attr.Value)),
}
case syscall.RTA_OIF:
routeIndex := int(native.Uint32(attr.Value[0:4]))
if link != nil && routeIndex != index {
// Ignore routes from other interfaces
continue
}
route.LinkIndex = routeIndex
}
}
res = append(res, route)
}
return res, nil
}