netlink/route_linux.go
2014-09-24 16:32:16 -07:00

169 lines
4.0 KiB
Go

package netlink
import (
"fmt"
"net"
"syscall"
"github.com/vishvananda/netlink/nl"
)
// RtAttr is shared so it is in netlink_linux.go
// RouteAdd will add a route to the system.
// Equivalent to: `ip route add $route`
func RouteAdd(route *Route) error {
req := nl.NewNetlinkRequest(syscall.RTM_NEWROUTE, syscall.NLM_F_CREATE|syscall.NLM_F_EXCL|syscall.NLM_F_ACK)
return routeHandle(route, req)
}
// RouteAdd will delete a route from the system.
// Equivalent to: `ip route del $route`
func RouteDel(route *Route) error {
req := nl.NewNetlinkRequest(syscall.RTM_DELROUTE, syscall.NLM_F_ACK)
return routeHandle(route, req)
}
func routeHandle(route *Route, req *nl.NetlinkRequest) error {
if route.Dst.IP == nil && route.Src == nil && route.Gw == nil {
return fmt.Errorf("one of Dst.IP, Src, or Gw must not be nil")
}
msg := nl.NewRtMsg()
msg.Scope = uint8(route.Scope)
family := -1
var rtAttrs []*nl.RtAttr
if route.Dst.IP != nil {
dstLen, _ := route.Dst.Mask.Size()
msg.Dst_len = uint8(dstLen)
dstFamily := nl.GetIPFamily(route.Dst.IP)
family = dstFamily
var dstData []byte
if dstFamily == FAMILY_V4 {
dstData = route.Dst.IP.To4()
} else {
dstData = route.Dst.IP.To16()
}
rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_DST, dstData))
}
if route.Src != nil {
srcFamily := nl.GetIPFamily(route.Src)
if family != -1 && family != srcFamily {
return fmt.Errorf("source and destination ip are not the same IP family")
}
family = srcFamily
var srcData []byte
if srcFamily == FAMILY_V4 {
srcData = route.Src.To4()
} else {
srcData = route.Src.To16()
}
// The commonly used src ip for routes is actually PREFSRC
rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_PREFSRC, srcData))
}
if route.Gw != nil {
gwFamily := nl.GetIPFamily(route.Gw)
if family != -1 && family != gwFamily {
return fmt.Errorf("gateway, source, and destination ip are not the same IP family")
}
family = gwFamily
var gwData []byte
if gwFamily == FAMILY_V4 {
gwData = route.Gw.To4()
} else {
gwData = route.Gw.To16()
}
rtAttrs = append(rtAttrs, nl.NewRtAttr(syscall.RTA_GATEWAY, gwData))
}
msg.Family = uint8(family)
req.AddData(msg)
for _, attr := range rtAttrs {
req.AddData(attr)
}
var (
b = make([]byte, 4)
native = nl.NativeEndian()
)
base := route.Link.Attrs()
native.PutUint32(b, uint32(base.Index))
req.AddData(nl.NewRtAttr(syscall.RTA_OIF, b))
_, err := req.Execute(syscall.NETLINK_ROUTE, 0)
return err
}
// 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
}
resLink, _ := LinkByIndex(routeIndex)
route.Link = resLink
}
}
res = append(res, route)
}
return res, nil
}