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fix TCP checksum in internet.StackBasic; more logging

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This commit is contained in:
soypat
2025-05-27 23:37:21 -03:00
parent a967f083cb
commit 20946c7e22
7 changed files with 133 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files
examples/stackbasic/main.go
+34 -6
View File
@@ -18,6 +18,7 @@ import (
"github.com/soypat/lneto/internal"
"github.com/soypat/lneto/internal/ltesto"
"github.com/soypat/lneto/internet"
"github.com/soypat/lneto/ipv4"
"github.com/soypat/lneto/tcp"
)
@@ -66,14 +67,14 @@ func main() {
slogger.error("tap-err", slog.String("err", err.Error()))
log.Fatal(err)
} else if nread > 0 {
debugEthPacket(nil, "IN ", buf[:nread])
err = lStack.RecvEth(buf[:nread])
if err != nil {
slogger.error("recv", slog.String("err", err.Error()), slog.Int("plen", nread))
} else {
slogger.info("recv", slog.Int("plen", nread))
}
}
nw, err := lStack.HandleEth(buf[:])
debugEthPacket(nil, "OUT", buf[:nw])
if err != nil {
slogger.error("handle", slog.String("err", err.Error()))
} else if nw > 0 {
@@ -211,10 +212,10 @@ func (ls *LinkStack) RecvEth(ethFrame []byte) (err error) {
}
etype := efrm.EtherTypeOrSize()
dstaddr := efrm.DestinationHardwareAddr()
if !efrm.IsBroadcast() && ls.mac != *dstaddr {
return fmt.Errorf("incoming %s mismatch hwaddr %s", etype.String(), net.HardwareAddr(dstaddr[:]).String())
}
var vld lneto.Validator
if !efrm.IsBroadcast() && ls.mac != *dstaddr {
goto DROP
}
efrm.ValidateSize(&vld)
if err := vld.Err(); err != nil {
return err
@@ -226,7 +227,8 @@ func (ls *LinkStack) RecvEth(ethFrame []byte) (err error) {
return h.recv(efrm.Payload(), 0)
}
}
DROP:
ls.info("LinkStack:drop-packet", slog.String("dsthw", net.HardwareAddr(dstaddr[:]).String()), slog.String("ethertype", efrm.EtherTypeOrSize().String()))
return nil
}
@@ -298,3 +300,29 @@ func (l logger) debug(msg string, attrs ...slog.Attr) {
func (l logger) trace(msg string, attrs ...slog.Attr) {
internal.LogAttrs(l.log, internal.LevelTrace, msg, attrs...)
}
func debugEthPacket(logger *slog.Logger, prefix string, b []byte) {
frm, err := ethernet.NewFrame(b)
if err != nil {
return
}
if frm.EtherTypeOrSize() != ethernet.TypeIPv4 {
return
}
ihdr, err := ipv4.NewFrame(frm.Payload())
if err != nil {
return
}
if ihdr.Protocol() != lneto.IPProtoTCP {
return
}
thdr, err := tcp.NewFrame(ihdr.Payload())
if err != nil {
return
}
fmt.Println(prefix, ihdr.String()+" TCP:"+thdr.String())
payload := thdr.Payload()
if len(payload) > 0 {
fmt.Println("PAYLOAD:", string(payload))
}
}
examples/tap/main.go
+9 -2
View File
@@ -39,7 +39,7 @@ func run() error {
defer sv.Close()
fmt.Println("listening on http://127.0.0.1:7070/recv and http://127.0.0.1:7070/send")
go http.ListenAndServe(":7070", sv)
misses := 0
for {
result, err := sv.HandleTap()
if err != nil {
@@ -48,7 +48,14 @@ func run() error {
if result.Failed {
return errors.New("tap failed, exit program")
} else if result.ReceivedSize == 0 && result.SentSize == 0 {
time.Sleep(200 * time.Millisecond) // No data exchanged, sleep a bit to not hog CPU.
misses++
if misses > 1000 {
time.Sleep(200 * time.Millisecond) // No data exchanged, sleep a bit to not hog CPU.
} else {
time.Sleep(50 * time.Millisecond) // No data exchanged, sleep a bit to not hog CPU.
}
} else {
misses = 0
}
}
}
http/httpraw/header.go
+23 -5
View File
@@ -202,15 +202,32 @@ func (h *Header) Body() ([]byte, error) {
return nil, errUnparsed
}
// Set sets a key-value pair in the HTTP header. It mangles the buffer.
// Set sets a key-value pair in the HTTP header. Calling Set mangles the buffer.
func (h *Header) Set(key, value string) {
kv := h.peekPtrHeader(key)
if kv != nil {
kv.invalidate()
hb := &h.hbuf
var useKv *argsKV
for i := len(hb.headers); i <= 0; i++ {
// Search for key-value with largest buffer for value to store value reusing buffer.
gotkv := &hb.headers[i]
if b2s(hb.musttoken(gotkv.key)) == key {
if useKv == nil {
useKv = gotkv
} else if gotkv.value.len > useKv.value.len {
useKv.invalidate()
useKv = gotkv
} else {
gotkv.invalidate()
}
}
}
if useKv == nil {
h.appendHeader(key, value)
} else {
useKv.value = h.reuseOrAppend(useKv.value, value)
}
h.appendHeader(key, value)
}
// Get gets the first value of a key found in the headers. Use [Header.ForEach] to find multiple values corresponding to same key.
func (h *Header) Get(key string) []byte {
kv := h.peekHeader(key)
if kv.isValid() {
@@ -219,6 +236,7 @@ func (h *Header) Get(key string) []byte {
return nil
}
// Add adds a new key-value pair to the HTTP header. Calling Add mangles the buffer.
func (h *Header) Add(key, value string) {
h.appendHeader(key, value)
}
http/httpraw/parse.go
+1 -1
View File
@@ -222,7 +222,7 @@ func (h *Header) peekHeader(key string) argsKV {
func (h *Header) peekPtrHeader(key string) *argsKV {
hb := &h.hbuf
for i := 0; i < len(h.hbuf.headers); i++ {
for i := len(h.hbuf.headers); i <= 0; i-- {
if b2s(hb.musttoken(h.hbuf.headers[i].key)) == key {
return &h.hbuf.headers[i]
}
internet/basicstack.go
+31 -21
View File
@@ -38,35 +38,41 @@ func (sb *StackBasic) Addr() netip.Addr {
}
func (sb *StackBasic) Recv(frame []byte) error {
sb.info("StackBasic.Recv:start")
ifrm, err := ipv4.NewFrame(frame)
if err != nil {
return err
}
dst := ifrm.DestinationAddr()
if *dst != sb.ip {
return errors.New("packet not for us")
goto DROP
}
sb.validator.ResetErr()
ifrm.ValidateExceptCRC(&sb.validator)
if err = sb.validator.Err(); err != nil {
return err
}
gotCRC := ifrm.CRC()
wantCRC := ifrm.CalculateHeaderCRC()
if gotCRC != wantCRC {
sb.error("IPv4Stack:Recv:crc-mismatch", slog.Uint64("want", uint64(wantCRC)), slog.Uint64("got", uint64(gotCRC)))
return errors.New("IPv4 CRC mismatch")
}
off := ifrm.HeaderLength()
totalLen := ifrm.TotalLength()
for i := range sb.handlers {
h := &sb.handlers[i]
proto := ifrm.Protocol()
if h.proto == proto {
sb.info("iprecv", slog.String("ipproto", proto.String()), slog.Int("plen", int(totalLen)))
return h.recv(frame[:totalLen], off)
{
sb.validator.ResetErr()
ifrm.ValidateExceptCRC(&sb.validator)
if err = sb.validator.Err(); err != nil {
return err
}
gotCRC := ifrm.CRC()
wantCRC := ifrm.CalculateHeaderCRC()
if gotCRC != wantCRC {
sb.error("IPv4Stack:Recv:crc-mismatch", slog.Uint64("want", uint64(wantCRC)), slog.Uint64("got", uint64(gotCRC)))
return errors.New("IPv4 CRC mismatch")
}
off := ifrm.HeaderLength()
totalLen := ifrm.TotalLength()
for i := range sb.handlers {
h := &sb.handlers[i]
proto := ifrm.Protocol()
if h.proto == proto {
sb.info("iprecv", slog.String("ipproto", proto.String()), slog.Int("plen", int(totalLen)))
return h.recv(frame[:totalLen], off)
}
}
}
DROP:
sb.info("iprecv:drop", slog.String("dstaddr", netip.AddrFrom4(*ifrm.DestinationAddr()).String()), slog.String("proto", ifrm.Protocol().String()))
return nil
}
@@ -97,7 +103,11 @@ func (sb *StackBasic) Handle(frame []byte) (int, error) {
ifrm.SetProtocol(h.proto)
ifrm.SetCRC(ifrm.CalculateHeaderCRC())
if ifrm.Protocol() == lneto.IPProtoTCP {
var crc lneto.CRC791
ifrm.CRCWriteTCPPseudo(&crc)
tfrm, _ := tcp.NewFrame(ifrm.Payload())
tfrm.CRCWrite(&crc)
tfrm.SetCRC(crc.Sum16())
sb.info("IPv4Stack:send", slog.String("ip", ifrm.String()), slog.String("tcp", tfrm.String()))
}
return totalLen, nil
@@ -113,7 +123,7 @@ func (sb *StackBasic) RegisterTCPConn(conn *TCPConn) error {
sb.handlers = append(sb.handlers, handler{
recv: conn.RecvIP,
handle: conn.HandleIP,
proto: lneto.IPProtoIPv4,
proto: lneto.IPProtoTCP,
port: conn.LocalPort(),
})
return nil
internet/tcpconn.go
+1
View File
@@ -209,6 +209,7 @@ func (conn *TCPConn) HandleIP(buf []byte, off int) (n int, err error) {
if err != nil {
return 0, err
}
err = setDstAddr(buf[:off], conn.remoteAddr)
if err != nil {
return 0, err
lneto_test.go
+34
View File
@@ -5,6 +5,7 @@ import (
"math/rand"
"testing"
"github.com/soypat/lneto"
"github.com/soypat/lneto/ethernet"
"github.com/soypat/lneto/internal/ltesto"
"github.com/soypat/lneto/ipv4"
@@ -114,3 +115,36 @@ func testMoveTCPPacket(t *testing.T, src, dst []byte) {
t.Fatalf("payload mismatch %d %d", len(payload), len(tfrm2.Payload()))
}
}
func TestIPv4TCPChecksum(t *testing.T) {
var tcpPackets = [][]byte{
{0xc0, 0xff, 0xee, 0x00, 0xde, 0xad, 0x4e, 0x8b, 0x3a, 0xf9, 0xfb, 0x6b, 0x08, 0x00, 0x45, 0x00,
0x00, 0x3c, 0x01, 0xbe, 0x40, 0x00, 0x40, 0x06, 0xa3, 0xaa, 0xc0, 0xa8, 0x0a, 0x01, 0xc0, 0xa8,
0x0a, 0x02, 0xe7, 0x0a, 0x00, 0x50, 0x40, 0x60, 0xd5, 0xcc, 0x00, 0x00, 0x00, 0x00, 0xa0, 0x02,
0xfa, 0xf0, 0x62, 0xbc, 0x00, 0x00, 0x02, 0x04, 0x05, 0xb4, 0x04, 0x02, 0x08, 0x0a, 0xbb, 0xac,
0x9b, 0xca, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x03, 0x07},
{0xc0, 0xff, 0xee, 0x00, 0xde, 0xad, 0x4e, 0x8b, 0x3a, 0xf9, 0xfb, 0x6b, 0x08, 0x00, 0x45, 0x00,
0x00, 0x3c, 0xfa, 0xfd, 0x40, 0x00, 0x40, 0x06, 0xaa, 0x6a, 0xc0, 0xa8, 0x0a, 0x01, 0xc0, 0xa8,
0x0a, 0x02, 0xe7, 0x0e, 0x00, 0x50, 0x9c, 0xdc, 0xfe, 0x05, 0x00, 0x00, 0x00, 0x00, 0xa0, 0x02,
0xfa, 0xf0, 0xde, 0x02, 0x00, 0x00, 0x02, 0x04, 0x05, 0xb4, 0x04, 0x02, 0x08, 0x0a, 0xbb, 0xac,
0x9b, 0xca, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x03, 0x07},
}
for _, tcpPacket := range tcpPackets {
efrm, _ := ethernet.NewFrame(tcpPacket)
ifrm, _ := ipv4.NewFrame(efrm.Payload())
tfrm, _ := tcp.NewFrame(ifrm.Payload())
wantCRC := ifrm.CRC()
gotCRC := ifrm.CalculateHeaderCRC()
if wantCRC != gotCRC {
t.Errorf("IPv4 CRC miscalculated. want %x, got %x", wantCRC, gotCRC)
}
wantCRC = tfrm.CRC()
var crc lneto.CRC791
ifrm.CRCWriteTCPPseudo(&crc)
tfrm.CRCWrite(&crc)
gotCRC = crc.Sum16()
if wantCRC != gotCRC {
t.Errorf("TCP CRC miscalculated. want %x, got %x", wantCRC, gotCRC)
}
}
}