package netlink
import (
"bytes"
"fmt"
"net"
"github.com/vishvananda/netlink/nl"
"golang.org/x/sys/unix"
)
const FibRuleInvert = 0x2
// RuleAdd adds a rule to the system.
// Equivalent to: ip rule add
func RuleAdd(rule *Rule) error {
return pkgHandle.RuleAdd(rule)
}
// RuleAdd adds a rule to the system.
// Equivalent to: ip rule add
func (h *Handle) RuleAdd(rule *Rule) error {
req := h.newNetlinkRequest(unix.RTM_NEWRULE, unix.NLM_F_CREATE|unix.NLM_F_EXCL|unix.NLM_F_ACK)
return ruleHandle(rule, req)
}
// RuleDel deletes a rule from the system.
// Equivalent to: ip rule del
func RuleDel(rule *Rule) error {
return pkgHandle.RuleDel(rule)
}
// RuleDel deletes a rule from the system.
// Equivalent to: ip rule del
func (h *Handle) RuleDel(rule *Rule) error {
req := h.newNetlinkRequest(unix.RTM_DELRULE, unix.NLM_F_ACK)
return ruleHandle(rule, req)
}
func ruleHandle(rule *Rule, req *nl.NetlinkRequest) error {
msg := nl.NewRtMsg()
msg.Family = unix.AF_INET
msg.Protocol = unix.RTPROT_BOOT
msg.Scope = unix.RT_SCOPE_UNIVERSE
msg.Table = unix.RT_TABLE_UNSPEC
msg.Type = rule.Type // usually 0, same as unix.RTN_UNSPEC
if msg.Type == 0 && req.NlMsghdr.Flags&unix.NLM_F_CREATE > 0 {
msg.Type = unix.RTN_UNICAST
}
if rule.Invert {
msg.Flags |= FibRuleInvert
}
if rule.Family != 0 {
msg.Family = uint8(rule.Family)
}
if rule.Table >= 0 && rule.Table < 256 {
msg.Table = uint8(rule.Table)
}
if rule.Tos != 0 {
msg.Tos = uint8(rule.Tos)
}
var dstFamily uint8
var rtAttrs []*nl.RtAttr
if rule.Dst != nil && rule.Dst.IP != nil {
dstLen, _ := rule.Dst.Mask.Size()
msg.Dst_len = uint8(dstLen)
msg.Family = uint8(nl.GetIPFamily(rule.Dst.IP))
dstFamily = msg.Family
var dstData []byte
if msg.Family == unix.AF_INET {
dstData = rule.Dst.IP.To4()
} else {
dstData = rule.Dst.IP.To16()
}
rtAttrs = append(rtAttrs, nl.NewRtAttr(unix.RTA_DST, dstData))
}
if rule.Src != nil && rule.Src.IP != nil {
msg.Family = uint8(nl.GetIPFamily(rule.Src.IP))
if dstFamily != 0 && dstFamily != msg.Family {
return fmt.Errorf("source and destination ip are not the same IP family")
}
srcLen, _ := rule.Src.Mask.Size()
msg.Src_len = uint8(srcLen)
var srcData []byte
if msg.Family == unix.AF_INET {
srcData = rule.Src.IP.To4()
} else {
srcData = rule.Src.IP.To16()
}
rtAttrs = append(rtAttrs, nl.NewRtAttr(unix.RTA_SRC, srcData))
}
req.AddData(msg)
for i := range rtAttrs {
req.AddData(rtAttrs[i])
}
if rule.Priority >= 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.Priority))
req.AddData(nl.NewRtAttr(nl.FRA_PRIORITY, b))
}
if rule.Mark != 0 || rule.Mask != nil {
b := make([]byte, 4)
native.PutUint32(b, rule.Mark)
req.AddData(nl.NewRtAttr(nl.FRA_FWMARK, b))
}
if rule.Mask != nil {
b := make([]byte, 4)
native.PutUint32(b, *rule.Mask)
req.AddData(nl.NewRtAttr(nl.FRA_FWMASK, b))
}
if rule.Flow >= 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.Flow))
req.AddData(nl.NewRtAttr(nl.FRA_FLOW, b))
}
if rule.TunID > 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.TunID))
req.AddData(nl.NewRtAttr(nl.FRA_TUN_ID, b))
}
if rule.Table >= 256 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.Table))
req.AddData(nl.NewRtAttr(nl.FRA_TABLE, b))
}
if msg.Table > 0 {
if rule.SuppressPrefixlen >= 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.SuppressPrefixlen))
req.AddData(nl.NewRtAttr(nl.FRA_SUPPRESS_PREFIXLEN, b))
}
if rule.SuppressIfgroup >= 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.SuppressIfgroup))
req.AddData(nl.NewRtAttr(nl.FRA_SUPPRESS_IFGROUP, b))
}
}
if rule.IifName != "" {
req.AddData(nl.NewRtAttr(nl.FRA_IIFNAME, []byte(rule.IifName+"\x00")))
}
if rule.OifName != "" {
req.AddData(nl.NewRtAttr(nl.FRA_OIFNAME, []byte(rule.OifName+"\x00")))
}
if rule.Goto >= 0 {
msg.Type = nl.FR_ACT_GOTO
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.Goto))
req.AddData(nl.NewRtAttr(nl.FRA_GOTO, b))
}
if rule.IPProto > 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.IPProto))
req.AddData(nl.NewRtAttr(nl.FRA_IP_PROTO, b))
}
if rule.Dport != nil {
b := rule.Dport.toRtAttrData()
req.AddData(nl.NewRtAttr(nl.FRA_DPORT_RANGE, b))
}
if rule.Sport != nil {
b := rule.Sport.toRtAttrData()
req.AddData(nl.NewRtAttr(nl.FRA_SPORT_RANGE, b))
}
if rule.UIDRange != nil {
b := rule.UIDRange.toRtAttrData()
req.AddData(nl.NewRtAttr(nl.FRA_UID_RANGE, b))
}
if rule.Protocol > 0 {
req.AddData(nl.NewRtAttr(nl.FRA_PROTOCOL, nl.Uint8Attr(rule.Protocol)))
}
_, err := req.Execute(unix.NETLINK_ROUTE, 0)
return err
}
// RuleList lists rules in the system.
// Equivalent to: ip rule list
func RuleList(family int) ([]Rule, error) {
return pkgHandle.RuleList(family)
}
// RuleList lists rules in the system.
// Equivalent to: ip rule list
func (h *Handle) RuleList(family int) ([]Rule, error) {
return h.RuleListFiltered(family, nil, 0)
}
// RuleListFiltered gets a list of rules in the system filtered by the
// specified rule template `filter`.
// Equivalent to: ip rule list
func RuleListFiltered(family int, filter *Rule, filterMask uint64) ([]Rule, error) {
return pkgHandle.RuleListFiltered(family, filter, filterMask)
}
// RuleListFiltered lists rules in the system.
// Equivalent to: ip rule list
func (h *Handle) RuleListFiltered(family int, filter *Rule, filterMask uint64) ([]Rule, error) {
req := h.newNetlinkRequest(unix.RTM_GETRULE, unix.NLM_F_DUMP|unix.NLM_F_REQUEST)
msg := nl.NewIfInfomsg(family)
req.AddData(msg)
msgs, err := req.Execute(unix.NETLINK_ROUTE, unix.RTM_NEWRULE)
if err != nil {
return nil, err
}
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.Priority = 0 // The default priority from kernel
rule.Invert = msg.Flags&FibRuleInvert > 0
rule.Family = int(msg.Family)
rule.Tos = uint(msg.Tos)
for j := range attrs {
switch attrs[j].Attr.Type {
case unix.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 = native.Uint32(attrs[j].Value[0:4])
case nl.FRA_FWMASK:
mask := native.Uint32(attrs[j].Value[0:4])
rule.Mask = &mask
case nl.FRA_TUN_ID:
rule.TunID = uint(native.Uint64(attrs[j].Value[0:8]))
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]))
case nl.FRA_IP_PROTO:
rule.IPProto = int(native.Uint32(attrs[j].Value[0:4]))
case nl.FRA_DPORT_RANGE:
rule.Dport = NewRulePortRange(native.Uint16(attrs[j].Value[0:2]), native.Uint16(attrs[j].Value[2:4]))
case nl.FRA_SPORT_RANGE:
rule.Sport = NewRulePortRange(native.Uint16(attrs[j].Value[0:2]), native.Uint16(attrs[j].Value[2:4]))
case nl.FRA_UID_RANGE:
rule.UIDRange = NewRuleUIDRange(native.Uint32(attrs[j].Value[0:4]), native.Uint32(attrs[j].Value[4:8]))
case nl.FRA_PROTOCOL:
rule.Protocol = uint8(attrs[j].Value[0])
}
}
if filter != nil {
switch {
case filterMask&RT_FILTER_SRC != 0 &&
(rule.Src == nil || rule.Src.String() != filter.Src.String()):
continue
case filterMask&RT_FILTER_DST != 0 &&
(rule.Dst == nil || rule.Dst.String() != filter.Dst.String()):
continue
case filterMask&RT_FILTER_TABLE != 0 &&
filter.Table != unix.RT_TABLE_UNSPEC && rule.Table != filter.Table:
continue
case filterMask&RT_FILTER_TOS != 0 && rule.Tos != filter.Tos:
continue
case filterMask&RT_FILTER_PRIORITY != 0 && rule.Priority != filter.Priority:
continue
case filterMask&RT_FILTER_MARK != 0 && rule.Mark != filter.Mark:
continue
case filterMask&RT_FILTER_MASK != 0 && !ptrEqual(rule.Mask, filter.Mask):
continue
}
}
res = append(res, *rule)
}
return res, nil
}
func (pr *RulePortRange) toRtAttrData() []byte {
b := [][]byte{make([]byte, 2), make([]byte, 2)}
native.PutUint16(b[0], pr.Start)
native.PutUint16(b[1], pr.End)
return bytes.Join(b, []byte{})
}
func (pr *RuleUIDRange) toRtAttrData() []byte {
b := [][]byte{make([]byte, 4), make([]byte, 4)}
native.PutUint32(b[0], pr.Start)
native.PutUint32(b[1], pr.End)
return bytes.Join(b, []byte{})
}
func ptrEqual(a, b *uint32) bool {
if a == b {
return true
}
if (a == nil) || (b == nil) {
return false
}
return *a == *b
}
func (r Rule) typeString() string {
switch r.Type {
case unix.RTN_UNSPEC: // zero
return ""
case unix.RTN_UNICAST:
return ""
case unix.RTN_LOCAL:
return "local"
case unix.RTN_BROADCAST:
return "broadcast"
case unix.RTN_ANYCAST:
return "anycast"
case unix.RTN_MULTICAST:
return "multicast"
case unix.RTN_BLACKHOLE:
return "blackhole"
case unix.RTN_UNREACHABLE:
return "unreachable"
case unix.RTN_PROHIBIT:
return "prohibit"
case unix.RTN_THROW:
return "throw"
case unix.RTN_NAT:
return "nat"
case unix.RTN_XRESOLVE:
return "xresolve"
default:
return fmt.Sprintf("type(0x%x)", r.Type)
}
}
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