// deserializeRoute decodes a binary netlink message into a Route struct
func deserializeRoute(m []byte) (Route, error) {
msg := nl.DeserializeRtMsg(m)
attrs, err := nl.ParseRouteAttr(m[msg.Len():])
if err != nil {
return Route{}, err
}
route := Route{
Scope: Scope(msg.Scope),
Protocol: int(msg.Protocol),
Table: int(msg.Table),
Type: int(msg.Type),
Tos: int(msg.Tos),
Flags: int(msg.Flags),
}
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:
route.LinkIndex = int(native.Uint32(attr.Value[0:4]))
case syscall.RTA_IIF:
route.ILinkIndex = int(native.Uint32(attr.Value[0:4]))
case syscall.RTA_PRIORITY:
route.Priority = int(native.Uint32(attr.Value[0:4]))
case syscall.RTA_TABLE:
route.Table = int(native.Uint32(attr.Value[0:4]))
}
}
return route, nil
}
// RuleList lists rules in the system.
// Equivalent to: ip rule list
func RuleList(family int) ([]Rule, error) {
req := nl.NewNetlinkRequest(syscall.RTM_GETRULE, syscall.NLM_F_DUMP|syscall.NLM_F_REQUEST)
msg := nl.NewIfInfomsg(family)
req.AddData(msg)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWRULE)
if err != nil {
return nil, err
}
native := nl.NativeEndian()
var res = make([]Rule, 0)
for i := range msgs {
msg := nl.DeserializeRtMsg(msgs[i])
attrs, err := nl.ParseRouteAttr(msgs[i][msg.Len():])
if err != nil {
return nil, err
}
rule := NewRule()
rule.RtMsg = msg
for j := range attrs {
switch attrs[j].Attr.Type {
case syscall.RTA_TABLE:
rule.Table = int(native.Uint32(attrs[j].Value[0:4]))
case nl.FRA_SRC:
rule.Src = &net.IPNet{
IP: attrs[j].Value,
Mask: net.CIDRMask(int(msg.Src_len), 8*len(attrs[j].Value)),
}
case nl.FRA_DST:
rule.Dst = &net.IPNet{
IP: attrs[j].Value,
Mask: net.CIDRMask(int(msg.Dst_len), 8*len(attrs[j].Value)),
}
case nl.FRA_FWMARK:
rule.Mark = int(native.Uint32(attrs[j].Value[0:4]))
case nl.FRA_FWMASK:
rule.Mask = int(native.Uint32(attrs[j].Value[0:4]))
case nl.FRA_TUN_ID:
rule.TunID = uint(native.Uint64(attrs[j].Value[0:4]))
case nl.FRA_IIFNAME:
rule.IifName = string(attrs[j].Value[:len(attrs[j].Value)-1])
case nl.FRA_OIFNAME:
rule.OifName = string(attrs[j].Value[:len(attrs[j].Value)-1])
case nl.FRA_SUPPRESS_PREFIXLEN:
i := native.Uint32(attrs[j].Value[0:4])
if i != 0xffffffff {
rule.SuppressPrefixlen = int(i)
}
case nl.FRA_SUPPRESS_IFGROUP:
i := native.Uint32(attrs[j].Value[0:4])
if i != 0xffffffff {
rule.SuppressIfgroup = int(i)
}
case nl.FRA_FLOW:
rule.Flow = int(native.Uint32(attrs[j].Value[0:4]))
case nl.FRA_GOTO:
rule.Goto = int(native.Uint32(attrs[j].Value[0:4]))
case nl.FRA_PRIORITY:
rule.Priority = int(native.Uint32(attrs[j].Value[0:4]))
}
}
res = append(res, *rule)
}
return res, nil
}
// RouteListFiltered gets a list of routes in the system filtered with specified rules.
// All rules must be defined in RouteFilter struct
func RouteListFiltered(family int, filter *Route, filterMask uint64) ([]Route, error) {
req := nl.NewNetlinkRequest(syscall.RTM_GETROUTE, syscall.NLM_F_DUMP)
infmsg := nl.NewIfInfomsg(family)
req.AddData(infmsg)
msgs, err := req.Execute(syscall.NETLINK_ROUTE, syscall.RTM_NEWROUTE)
if err != nil {
return nil, err
}
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 {
if filter == nil || filter != nil && filterMask&RT_FILTER_TABLE == 0 {
// Ignore non-main tables
continue
}
}
route, err := deserializeRoute(m)
if err != nil {
return nil, err
}
if filter != nil {
switch {
case filterMask&RT_FILTER_TABLE != 0 && route.Table != filter.Table:
continue
case filterMask&RT_FILTER_PROTOCOL != 0 && route.Protocol != filter.Protocol:
continue
case filterMask&RT_FILTER_SCOPE != 0 && route.Scope != filter.Scope:
continue
case filterMask&RT_FILTER_TYPE != 0 && route.Type != filter.Type:
continue
case filterMask&RT_FILTER_TOS != 0 && route.Tos != filter.Tos:
continue
case filterMask&RT_FILTER_OIF != 0 && route.LinkIndex != filter.LinkIndex:
continue
case filterMask&RT_FILTER_IIF != 0 && route.ILinkIndex != filter.ILinkIndex:
continue
case filterMask&RT_FILTER_GW != 0 && !route.Gw.Equal(filter.Gw):
continue
case filterMask&RT_FILTER_SRC != 0 && !route.Src.Equal(filter.Src):
continue
case filterMask&RT_FILTER_DST != 0 && filter.Dst != nil:
if route.Dst == nil {
continue
}
aMaskLen, aMaskBits := route.Dst.Mask.Size()
bMaskLen, bMaskBits := filter.Dst.Mask.Size()
if !(route.Dst.IP.Equal(filter.Dst.IP) && aMaskLen == bMaskLen && aMaskBits == bMaskBits) {
continue
}
}
}
res = append(res, route)
}
return res, nil
}