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errors: replace errors.Wrap() with errors.Is()
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@ti-mo
ti-mo committed Dec 20, 2022
1 parent 9a0cb3c commit 4265fd9
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Showing 24 changed files with 408 additions and 587 deletions.
128 changes: 57 additions & 71 deletions attribute_types.go
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Original file line number Diff line number Diff line change
Expand Up @@ -5,23 +5,9 @@ import (
"time"

"github.com/mdlayher/netlink"
"github.com/pkg/errors"
"github.com/ti-mo/netfilter"
)

const (
opUnHelper = "Helper unmarshal"
opUnProtoInfo = "ProtoInfo unmarshal"
opUnProtoInfoTCP = "ProtoInfoTCP unmarshal"
opUnProtoInfoDCCP = "ProtoInfoDCCP unmarshal"
opUnProtoInfoSCTP = "ProtoInfoSCTP unmarshal"
opUnCounter = "Counter unmarshal"
opUnTimestamp = "Timestamp unmarshal"
opUnSecurity = "Security unmarshal"
opUnSeqAdj = "SeqAdj unmarshal"
opUnSynProxy = "SynProxy unmarshal"
)

// nestedFlag returns true if the NLA_F_NESTED flag is set on typ.
func nestedFlag(typ uint16) bool {
return typ&netlink.Nested != 0
Expand All @@ -38,17 +24,16 @@ func (hlp Helper) filled() bool {
return hlp.Name != "" || len(hlp.Info) != 0
}

// unmarshal unmarshals a netfilter.Attribute into a Helper.
// unmarshal unmarshals netlink attributes into a Helper.
func (hlp *Helper) unmarshal(ad *netlink.AttributeDecoder) error {

for ad.Next() {
switch helperType(ad.Type()) {
case ctaHelpName:
hlp.Name = ad.String()
case ctaHelpInfo:
hlp.Info = ad.Bytes()
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -57,7 +42,6 @@ func (hlp *Helper) unmarshal(ad *netlink.AttributeDecoder) error {

// marshal marshals a Helper into a netfilter.Attribute.
func (hlp Helper) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(ctaHelp), Nested: true, Children: make([]netfilter.Attribute, 1, 2)}

nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaHelpName), Data: []byte(hlp.Name)}
Expand All @@ -82,25 +66,25 @@ func (pi ProtoInfo) filled() bool {
return pi.TCP != nil || pi.DCCP != nil || pi.SCTP != nil
}

// unmarshal unmarshals a netfilter.Attribute into a ProtoInfo structure.
// unmarshal unmarshals netlink attributes into a ProtoInfo.
// one of three ProtoInfo types; TCP, DCCP or SCTP.
func (pi *ProtoInfo) unmarshal(ad *netlink.AttributeDecoder) error {

// Make sure we don't unmarshal into the same ProtoInfo twice.
if pi.filled() {
return errReusedProtoInfo
}

if ad.Len() != 1 {
return errors.Wrap(errNeedSingleChild, opUnProtoInfo)
return errNeedSingleChild
}

// Step into the single nested child, return on error.
if !ad.Next() {
return ad.Err()
}

switch protoInfoType(ad.Type()) {
t := protoInfoType(ad.Type())
switch t {
case ctaProtoInfoTCP:
var tpi ProtoInfoTCP
ad.Nested(tpi.unmarshal)
Expand All @@ -114,15 +98,18 @@ func (pi *ProtoInfo) unmarshal(ad *netlink.AttributeDecoder) error {
ad.Nested(spi.unmarshal)
pi.SCTP = &spi
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}

return ad.Err()
if err := ad.Err(); err != nil {
return fmt.Errorf("unmarshal %s: %w", t, err)
}

return nil
}

// marshal marshals a ProtoInfo into a netfilter.Attribute.
func (pi ProtoInfo) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(ctaProtoInfo), Nested: true, Children: make([]netfilter.Attribute, 0, 1)}

if pi.TCP != nil {
Expand All @@ -146,12 +133,11 @@ type ProtoInfoTCP struct {
ReplyFlags uint16
}

// unmarshal unmarshals a netfilter.Attribute into a ProtoInfoTCP.
// unmarshal unmarshals netlink attributes into a ProtoInfoTCP.
func (tpi *ProtoInfoTCP) unmarshal(ad *netlink.AttributeDecoder) error {

// A ProtoInfoTCP has at least 3 members, TCP_STATE and TCP_FLAGS_ORIG/REPLY.
if ad.Len() < 3 {
return errors.Wrap(errNeedChildren, opUnProtoInfoTCP)
return errNeedChildren
}

for ad.Next() {
Expand All @@ -167,7 +153,7 @@ func (tpi *ProtoInfoTCP) unmarshal(ad *netlink.AttributeDecoder) error {
case ctaProtoInfoTCPFlagsReply:
tpi.ReplyFlags = ad.Uint16()
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -176,12 +162,17 @@ func (tpi *ProtoInfoTCP) unmarshal(ad *netlink.AttributeDecoder) error {

// marshal marshals a ProtoInfoTCP into a netfilter.Attribute.
func (tpi ProtoInfoTCP) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(ctaProtoInfoTCP), Nested: true, Children: make([]netfilter.Attribute, 3, 5)}

nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaProtoInfoTCPState), Data: []byte{tpi.State}}
nfa.Children[1] = netfilter.Attribute{Type: uint16(ctaProtoInfoTCPWScaleOriginal), Data: []byte{tpi.OriginalWindowScale}}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaProtoInfoTCPWScaleReply), Data: []byte{tpi.ReplyWindowScale}}
nfa.Children[0] = netfilter.Attribute{
Type: uint16(ctaProtoInfoTCPState), Data: []byte{tpi.State},
}
nfa.Children[1] = netfilter.Attribute{
Type: uint16(ctaProtoInfoTCPWScaleOriginal), Data: []byte{tpi.OriginalWindowScale},
}
nfa.Children[2] = netfilter.Attribute{
Type: uint16(ctaProtoInfoTCPWScaleReply), Data: []byte{tpi.ReplyWindowScale},
}

// Only append TCP flags to attributes when either of them is non-zero.
if tpi.OriginalFlags != 0 || tpi.ReplyFlags != 0 {
Expand All @@ -199,11 +190,10 @@ type ProtoInfoDCCP struct {
HandshakeSeq uint64
}

// unmarshal unmarshals a netfilter.Attribute into a ProtoInfoTCP.
// unmarshal unmarshals netlink attributes into a ProtoInfoDCCP.
func (dpi *ProtoInfoDCCP) unmarshal(ad *netlink.AttributeDecoder) error {

if ad.Len() == 0 {
return errors.Wrap(errNeedChildren, opUnProtoInfoDCCP)
return errNeedChildren
}

for ad.Next() {
Expand All @@ -215,7 +205,7 @@ func (dpi *ProtoInfoDCCP) unmarshal(ad *netlink.AttributeDecoder) error {
case ctaProtoInfoDCCPHandshakeSeq:
dpi.HandshakeSeq = ad.Uint64()
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -224,12 +214,12 @@ func (dpi *ProtoInfoDCCP) unmarshal(ad *netlink.AttributeDecoder) error {

// marshal marshals a ProtoInfoDCCP into a netfilter.Attribute.
func (dpi ProtoInfoDCCP) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(ctaProtoInfoDCCP), Nested: true, Children: make([]netfilter.Attribute, 3)}

nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaProtoInfoDCCPState), Data: []byte{dpi.State}}
nfa.Children[1] = netfilter.Attribute{Type: uint16(ctaProtoInfoDCCPRole), Data: []byte{dpi.Role}}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaProtoInfoDCCPHandshakeSeq), Data: netfilter.Uint64Bytes(dpi.HandshakeSeq)}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaProtoInfoDCCPHandshakeSeq),
Data: netfilter.Uint64Bytes(dpi.HandshakeSeq)}

return nfa
}
Expand All @@ -240,11 +230,10 @@ type ProtoInfoSCTP struct {
VTagOriginal, VTagReply uint32
}

// unmarshal unmarshals a netfilter.Attribute into a ProtoInfoSCTP.
// unmarshal unmarshals netlink attributes into a ProtoInfoSCTP.
func (spi *ProtoInfoSCTP) unmarshal(ad *netlink.AttributeDecoder) error {

if ad.Len() == 0 {
return errors.Wrap(errNeedChildren, opUnProtoInfoSCTP)
return errNeedChildren
}

for ad.Next() {
Expand All @@ -256,7 +245,7 @@ func (spi *ProtoInfoSCTP) unmarshal(ad *netlink.AttributeDecoder) error {
case ctaProtoInfoSCTPVtagReply:
spi.VTagReply = ad.Uint32()
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -265,12 +254,13 @@ func (spi *ProtoInfoSCTP) unmarshal(ad *netlink.AttributeDecoder) error {

// marshal marshals a ProtoInfoSCTP into a netfilter.Attribute.
func (spi ProtoInfoSCTP) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(ctaProtoInfoSCTP), Nested: true, Children: make([]netfilter.Attribute, 3)}

nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaProtoInfoSCTPState), Data: []byte{spi.State}}
nfa.Children[1] = netfilter.Attribute{Type: uint16(ctaProtoInfoSCTPVTagOriginal), Data: netfilter.Uint32Bytes(spi.VTagOriginal)}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaProtoInfoSCTPVtagReply), Data: netfilter.Uint32Bytes(spi.VTagReply)}
nfa.Children[1] = netfilter.Attribute{Type: uint16(ctaProtoInfoSCTPVTagOriginal),
Data: netfilter.Uint32Bytes(spi.VTagOriginal)}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaProtoInfoSCTPVtagReply),
Data: netfilter.Uint32Bytes(spi.VTagReply)}

return nfa
}
Expand Down Expand Up @@ -302,13 +292,12 @@ func (ctr Counter) filled() bool {
return ctr.Bytes != 0 && ctr.Packets != 0
}

// unmarshal unmarshals a nested counter attribute into a Counter structure.
// unmarshal unmarshals netlink attributes into a Counter.
func (ctr *Counter) unmarshal(ad *netlink.AttributeDecoder) error {

// A Counter consists of packet and byte attributes but may have
// help attributes as well if nf_conntrack_helper enabled
if ad.Len() < 2 {
return errors.Wrap(errNeedChildren, opUnCounter)
return errNeedChildren
}

for ad.Next() {
Expand All @@ -321,7 +310,7 @@ func (ctr *Counter) unmarshal(ad *netlink.AttributeDecoder) error {
// Ignore padding attributes that show up if nf_conntrack_helper is enabled.
continue
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -336,12 +325,11 @@ type Timestamp struct {
Stop time.Time
}

// unmarshal unmarshals a nested timestamp attribute into a conntrack.Timestamp structure.
// unmarshal unmarshals netlink attributes into a Timestamp.
func (ts *Timestamp) unmarshal(ad *netlink.AttributeDecoder) error {

// A Timestamp will always have at least a start time
if ad.Len() == 0 {
return errors.Wrap(errNeedSingleChild, opUnTimestamp)
return errNeedSingleChild
}

for ad.Next() {
Expand All @@ -351,7 +339,7 @@ func (ts *Timestamp) unmarshal(ad *netlink.AttributeDecoder) error {
case ctaTimestampStop:
ts.Stop = time.Unix(0, int64(ad.Uint64()))
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -363,20 +351,19 @@ func (ts *Timestamp) unmarshal(ad *netlink.AttributeDecoder) error {
// This attribute cannot be changed on a connection and thus cannot be marshaled.
type Security string

// unmarshal unmarshals a nested security attribute into a conntrack.Security structure.
// unmarshal unmarshals netlink attributes into a Security.
func (sec *Security) unmarshal(ad *netlink.AttributeDecoder) error {

// A SecurityContext has at least a name
if ad.Len() == 0 {
return errors.Wrap(errNeedChildren, opUnSecurity)
return errNeedChildren
}

for ad.Next() {
switch securityType(ad.Type()) {
case ctaSecCtxName:
*sec = Security(ad.Bytes())
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand Down Expand Up @@ -410,13 +397,11 @@ func (seq SequenceAdjust) filled() bool {
return seq.Position != 0 && seq.OffsetAfter != 0 && seq.OffsetBefore != 0
}

// unmarshal unmarshals a nested sequence adjustment attribute into a
// conntrack.SequenceAdjust structure.
// unmarshal unmarshals netlink attributes into a SequenceAdjust.
func (seq *SequenceAdjust) unmarshal(ad *netlink.AttributeDecoder) error {

// A SequenceAdjust message should come with at least 1 child.
if ad.Len() == 0 {
return errors.Wrap(errNeedSingleChild, opUnSeqAdj)
return errNeedSingleChild
}

for ad.Next() {
Expand All @@ -428,7 +413,7 @@ func (seq *SequenceAdjust) unmarshal(ad *netlink.AttributeDecoder) error {
case ctaSeqAdjOffsetAfter:
seq.OffsetAfter = ad.Uint32()
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -446,9 +431,12 @@ func (seq SequenceAdjust) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(at), Nested: true, Children: make([]netfilter.Attribute, 3)}

nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaSeqAdjCorrectionPos), Data: netfilter.Uint32Bytes(seq.Position)}
nfa.Children[1] = netfilter.Attribute{Type: uint16(ctaSeqAdjOffsetBefore), Data: netfilter.Uint32Bytes(seq.OffsetBefore)}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaSeqAdjOffsetAfter), Data: netfilter.Uint32Bytes(seq.OffsetAfter)}
nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaSeqAdjCorrectionPos),
Data: netfilter.Uint32Bytes(seq.Position)}
nfa.Children[1] = netfilter.Attribute{Type: uint16(ctaSeqAdjOffsetBefore),
Data: netfilter.Uint32Bytes(seq.OffsetBefore)}
nfa.Children[2] = netfilter.Attribute{Type: uint16(ctaSeqAdjOffsetAfter),
Data: netfilter.Uint32Bytes(seq.OffsetAfter)}

return nfa
}
Expand All @@ -466,11 +454,10 @@ func (sp SynProxy) filled() bool {
return sp.ISN != 0 || sp.ITS != 0 || sp.TSOff != 0
}

// unmarshal unmarshals a SYN proxy attribute into a SynProxy structure.
// unmarshal unmarshals netlink attributes into a SynProxy.
func (sp *SynProxy) unmarshal(ad *netlink.AttributeDecoder) error {

if ad.Len() == 0 {
return errors.Wrap(errNeedSingleChild, opUnSynProxy)
return errNeedSingleChild
}

for ad.Next() {
Expand All @@ -482,7 +469,7 @@ func (sp *SynProxy) unmarshal(ad *netlink.AttributeDecoder) error {
case ctaSynProxyTSOff:
sp.TSOff = ad.Uint32()
default:
return fmt.Errorf(errAttributeChild, ad.Type())
return fmt.Errorf("child type %d: %w", ad.Type(), errUnknownAttribute)
}
}

Expand All @@ -491,7 +478,6 @@ func (sp *SynProxy) unmarshal(ad *netlink.AttributeDecoder) error {

// marshal marshals a SynProxy into a netfilter.Attribute.
func (sp SynProxy) marshal() netfilter.Attribute {

nfa := netfilter.Attribute{Type: uint16(ctaSynProxy), Nested: true, Children: make([]netfilter.Attribute, 3)}

nfa.Children[0] = netfilter.Attribute{Type: uint16(ctaSynProxyISN), Data: netfilter.Uint32Bytes(sp.ISN)}
Expand Down
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