netlink/rule_linux.go
Tobias Klauser 4ef7bcbf15 Don't re-initialize or shadow package level var native to fix data race
The package level var native (holding the native endianness) is
initialized at package load time. Thus there is no need to re-initalize
it in functions using it, e.g. (*Handle).filterModify, parseU32Data,
parseFwData, parseBpfData and parseMatchAllData.

This fixes a data race between these functions and any read access of
var native, e.g. in LinkDeserialize as reported in issue .

Also don't re-declare local variables shadowing the global package-level
var.

Fixes 

Signed-off-by: Tobias Klauser <tobias@cilium.io>
2021-05-10 07:24:37 -07:00

294 lines
8.0 KiB
Go

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 = unix.RTN_UNSPEC
if 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 {
b := make([]byte, 4)
native.PutUint32(b, uint32(rule.Mark))
req.AddData(nl.NewRtAttr(nl.FRA_FWMARK, b))
}
if rule.Mask >= 0 {
b := make([]byte, 4)
native.PutUint32(b, uint32(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.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))
}
_, 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.Invert = msg.Flags&FibRuleInvert > 0
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 = 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]))
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]))
}
}
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 && 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{})
}