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use lneto.ErrDropPacket where appropiate; clean up examples/xnet output

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This commit is contained in:
soypat
2025-12-31 18:15:34 -03:00
parent 243d1a720d
commit dc374169dc
7 changed files with 43 additions and 19 deletions
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errors.go
+1
View File
@@ -21,6 +21,7 @@ type errGeneric uint8
const (
_ errGeneric = iota // non-initialized err
ErrPacketDrop // packet dropped
ErrBadCRC // incorrect checksum
)
func (err errGeneric) Error() string {
ethernet/definitions.go
+19
View File
@@ -1,9 +1,28 @@
package ethernet
import (
"strconv"
)
const (
sizeHeaderNoVLAN = 14
)
// AppendAddr appends the text representation of the hardware address to the destination buffer.
func AppendAddr(dst []byte, hwAddr [6]byte) []byte {
for i, b := range hwAddr {
if i != 0 {
dst = append(dst, ':')
}
if b < 16 {
dst = append(dst, '0')
}
dst = strconv.AppendUint(dst, uint64(b), 16)
}
return dst
}
// BroadcastAddr returns the all 0xff's broadcast hardware/MAC/EUI/OUI address.
func BroadcastAddr() [6]byte {
return [6]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff}
}
examples/xnet/main.go
+4
View File
@@ -1,6 +1,7 @@
package main
import (
"bytes"
"encoding/hex"
"errors"
"flag"
@@ -17,6 +18,7 @@ import (
"github.com/soypat/lneto"
"github.com/soypat/lneto/dns"
"github.com/soypat/lneto/ethernet"
"github.com/soypat/lneto/http/httpraw"
"github.com/soypat/lneto/internal"
"github.com/soypat/lneto/internal/ltesto"
@@ -129,6 +131,8 @@ func run() (err error) {
pfbuf = fmt.Appendf(pfbuf[:0], "%-3s %3d", context, len(pkt))
pfbuf = append(pfbuf, ' ', '[')
pfbuf, err = pf.FormatFrames(pfbuf, frames, pkt)
pfbuf = bytes.ReplaceAll(pfbuf, stack.Addr().AppendTo(nil), []byte("us"))
pfbuf = bytes.ReplaceAll(pfbuf, ethernet.AppendAddr(nil, stack.HardwareAddress()), []byte("us"))
pfbuf = append(pfbuf, ']', '\n')
if err != nil {
return err
internet/definitions.go
+5 -2
View File
@@ -6,6 +6,8 @@ import (
"math"
"net"
"slices"
"github.com/soypat/lneto"
)
// StackNode is an abstraction of a packet exchanging protocol controller. This is the building block for all protocols,
@@ -148,19 +150,20 @@ func (h *handlers) nodeByPortProto(port uint16, protocol uint16) *node {
func (h *handlers) demuxByProto(buf []byte, offset int, proto uint16) (*node, error) {
node := h.nodeByProto(proto)
if node == nil {
return nil, nil
return nil, lneto.ErrPacketDrop
}
err := node.demux(buf, offset)
if h.tryHandleError(node, err) {
err = nil
}
return node, err
}
func (h *handlers) demuxByPort(buf []byte, offset int, port uint16) (*node, error) {
node := h.nodeByPort(port)
if node == nil {
return nil, nil
return nil, lneto.ErrPacketDrop
}
err := node.demux(buf, offset)
if h.tryHandleError(node, err) {
internet/pcap/format.go
+2 -9
View File
@@ -9,6 +9,7 @@ import (
"strings"
"github.com/soypat/lneto"
"github.com/soypat/lneto/ethernet"
"github.com/soypat/lneto/tcp"
)
@@ -122,15 +123,7 @@ func (f *Formatter) formatField(dst []byte, pktStartOff int, field FrameField, p
} else if field.BitLength == 4*8 {
dst = netip.AddrFrom4([4]byte(f.buf)).AppendTo(dst)
} else if field.BitLength == 6*8 {
for i := range f.buf {
if i != 0 {
dst = append(dst, ':')
}
if f.buf[i] < 16 {
dst = append(dst, '0')
}
dst = strconv.AppendUint(dst, uint64(f.buf[i]), 16)
}
dst = ethernet.AppendAddr(dst, [6]byte(f.buf))
} else if field.BitLength == 16*8 {
dst = netip.AddrFrom16([16]byte(f.buf)).AppendTo(dst)
} else {
internet/stack-ip.go
+10 -6
View File
@@ -80,19 +80,21 @@ func (sb *StackIP) Demux(carrierData []byte, offset int) error {
}
dst := ifrm.DestinationAddr()
if sb.ip != ([4]byte{}) && *dst != sb.ip {
return errors.New("not meant for us") // Not meant for us.
sb.handlers.debug("ip:not-for-us")
return lneto.ErrPacketDrop // Not meant for us.
}
sb.validator.ResetErr()
ifrm.ValidateExceptCRC(&sb.validator)
if err = sb.validator.ErrPop(); err != nil {
sb.handlers.error("ip:Demux.validate")
return err
}
gotCRC := ifrm.CRC()
wantCRC := ifrm.CalculateHeaderCRC()
if gotCRC != wantCRC {
sb.handlers.error("StackIP:Demux:crc-mismatch", slog.Uint64("want", uint64(wantCRC)), slog.Uint64("got", uint64(gotCRC)))
return errors.New("IPv4 CRC mismatch")
return lneto.ErrBadCRC
}
off := ifrm.HeaderLength()
totalLen := ifrm.TotalLength()
@@ -104,8 +106,8 @@ func (sb *StackIP) Demux(carrierData []byte, offset int) error {
// nodeIdx := getNodeByProto(sb.handlers, uint16(proto))
if node == nil {
// Drop packet.
sb.handlers.info("iprecv:drop", slog.String("dstaddr", netip.AddrFrom4(*ifrm.DestinationAddr()).String()), slog.String("proto", ifrm.Protocol().String()))
return nil
sb.handlers.info("ip:demux.drop", slog.String("dstaddr", netip.AddrFrom4(*ifrm.DestinationAddr()).String()), slog.String("proto", ifrm.Protocol().String()))
return lneto.ErrPacketDrop
}
// Incoming CRC Validation of common IP Protocols.
var crc lneto.CRC791
@@ -118,7 +120,8 @@ func (sb *StackIP) Demux(carrierData []byte, offset int) error {
}
tfrm.CRCWrite(&crc)
if crc.Sum16() != tfrm.CRC() {
return errors.New("TCP CRC mismatch")
sb.handlers.error("ip:demux.tcpcrc")
return lneto.ErrBadCRC
}
case lneto.IPProtoUDP:
ifrm.CRCWriteUDPPseudo(&crc)
@@ -128,7 +131,8 @@ func (sb *StackIP) Demux(carrierData []byte, offset int) error {
}
ufrm.CRCWriteIPv4(&crc)
if crc.Sum16() != ufrm.CRC() {
return errors.New("UDP CRC mismatch")
sb.handlers.error("ip:demux.udpcrc")
return lneto.ErrBadCRC
}
}
sb.handlers.info("ipDemux", slog.String("ipproto", proto.String()), slog.Int("plen", int(totalLen)))
internet/stack-udpport.go
+2 -2
View File
@@ -43,13 +43,13 @@ func (sudp *StackUDPPort) Demux(carrierData []byte, frameOffset int) error {
}
dst := ufrm.DestinationPort()
if dst != sudp.h.port {
return nil // Not meant for us.
return lneto.ErrPacketDrop // Not meant for us.
}
// TODO remote ip address handling.
src := ufrm.SourcePort()
if sudp.rmport != 0 && src != sudp.rmport {
return nil // Not from our target remote port.
return lneto.ErrPacketDrop // Not from our target remote port.
}
err = sudp.h.demux(carrierData, frameOffset+8)
if err != nil {