mirror of
https://github.com/slackhq/nebula.git
synced 2026-05-16 04:47:38 +02:00
1023 lines
31 KiB
Go
1023 lines
31 KiB
Go
package batch
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import (
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"encoding/binary"
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"testing"
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"github.com/slackhq/nebula/overlay/tio"
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)
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// fakeTunWriter records plain Writes and WriteGSO calls without touching a
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// real TUN fd. WriteGSO records the IP header, transport header, and
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// borrowed payload fragments separately so tests can inspect each.
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type fakeTunWriter struct {
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gsoEnabled bool
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writes [][]byte
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gsoWrites []fakeGSOWrite
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}
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// fakeGSOWrite captures one WriteGSO call. hdr is the concatenation of the
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// IP and transport headers (in that order), gsoSize / isV6 / csumStart are
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// derived from the call so existing assertions keep working unchanged.
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type fakeGSOWrite struct {
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hdr []byte
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pays [][]byte
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gsoSize uint16
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isV6 bool
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csumStart uint16
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}
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// total returns hdrLen + sum of pay lens.
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func (g fakeGSOWrite) total() int {
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n := len(g.hdr)
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for _, p := range g.pays {
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n += len(p)
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}
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return n
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}
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// payLen sums the pays.
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func (g fakeGSOWrite) payLen() int {
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var n int
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for _, p := range g.pays {
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n += len(p)
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}
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return n
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}
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func (w *fakeTunWriter) Write(p []byte) (int, error) {
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buf := make([]byte, len(p))
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copy(buf, p)
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w.writes = append(w.writes, buf)
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return len(p), nil
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}
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func (w *fakeTunWriter) WriteGSO(hdr []byte, transportHdr []byte, pays [][]byte, _ tio.GSOProto) error {
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hcopy := make([]byte, len(hdr)+len(transportHdr))
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copy(hcopy, hdr)
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copy(hcopy[len(hdr):], transportHdr)
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paysCopy := make([][]byte, len(pays))
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for i, p := range pays {
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pc := make([]byte, len(p))
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copy(pc, p)
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paysCopy[i] = pc
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}
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var gsoSize uint16
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if len(pays) > 1 {
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gsoSize = uint16(len(pays[0]))
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}
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isV6 := len(hdr) > 0 && hdr[0]>>4 == 6
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w.gsoWrites = append(w.gsoWrites, fakeGSOWrite{
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hdr: hcopy,
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pays: paysCopy,
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gsoSize: gsoSize,
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isV6: isV6,
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csumStart: uint16(len(hdr)),
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})
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return nil
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}
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func (w *fakeTunWriter) Capabilities() tio.Capabilities {
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return tio.Capabilities{TSO: w.gsoEnabled, USO: w.gsoEnabled}
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}
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// buildTCPv4 constructs a minimal IPv4+TCP packet with the given payload,
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// seq, and flags. Assumes no IP options and a 20-byte TCP header.
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func buildTCPv4(seq uint32, flags byte, payload []byte) []byte {
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return buildTCPv4Ports(1000, 2000, seq, flags, payload)
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}
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// buildTCPv4Ports is buildTCPv4 with caller-specified ports so tests can
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// build distinct flows.
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func buildTCPv4Ports(sport, dport uint16, seq uint32, flags byte, payload []byte) []byte {
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const ipHdrLen = 20
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const tcpHdrLen = 20
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total := ipHdrLen + tcpHdrLen + len(payload)
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pkt := make([]byte, total)
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pkt[0] = 0x45
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pkt[1] = 0x00
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binary.BigEndian.PutUint16(pkt[2:4], uint16(total))
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binary.BigEndian.PutUint16(pkt[4:6], 0)
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binary.BigEndian.PutUint16(pkt[6:8], 0x4000)
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pkt[8] = 64
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pkt[9] = ipProtoTCP
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copy(pkt[12:16], []byte{10, 0, 0, 1})
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copy(pkt[16:20], []byte{10, 0, 0, 2})
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binary.BigEndian.PutUint16(pkt[20:22], sport)
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binary.BigEndian.PutUint16(pkt[22:24], dport)
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binary.BigEndian.PutUint32(pkt[24:28], seq)
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binary.BigEndian.PutUint32(pkt[28:32], 12345)
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pkt[32] = 0x50
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pkt[33] = flags
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binary.BigEndian.PutUint16(pkt[34:36], 0xffff)
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copy(pkt[40:], payload)
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return pkt
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}
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const (
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tcpAck = 0x10
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tcpPsh = 0x08
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tcpSyn = 0x02
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tcpFin = 0x01
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tcpAckPsh = tcpAck | tcpPsh
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)
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func TestCoalescerPassthroughWhenGSOUnavailable(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: false}
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c := NewTCPCoalescer(w)
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pkt := buildTCPv4(1000, tcpAck, []byte("hello"))
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if err := c.Commit(pkt); err != nil {
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t.Fatal(err)
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}
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// No sync write — passthrough is deferred to Flush.
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if len(w.writes) != 0 || len(w.gsoWrites) != 0 {
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t.Fatalf("no Add-time writes: got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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if len(w.writes) != 1 || len(w.gsoWrites) != 0 {
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t.Fatalf("want single plain write, got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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func TestCoalescerNonTCPPassthrough(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pkt := make([]byte, 28)
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pkt[0] = 0x45
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binary.BigEndian.PutUint16(pkt[2:4], 28)
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pkt[9] = 1
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copy(pkt[12:16], []byte{10, 0, 0, 1})
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copy(pkt[16:20], []byte{10, 0, 0, 2})
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if err := c.Commit(pkt); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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if len(w.writes) != 1 || len(w.gsoWrites) != 0 {
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t.Fatalf("ICMP should pass through unchanged")
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}
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}
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func TestCoalescerSeedThenFlushAlone(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pkt := buildTCPv4(1000, tcpAck, make([]byte, 1000))
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if err := c.Commit(pkt); err != nil {
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t.Fatal(err)
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}
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if len(w.writes) != 0 || len(w.gsoWrites) != 0 {
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t.Fatalf("unexpected output before flush")
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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// Single-segment flush goes through WriteGSO with GSO_NONE
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// (virtio NEEDS_CSUM lets the kernel fill in the L4 csum).
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if len(w.gsoWrites) != 1 || len(w.writes) != 0 {
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t.Fatalf("single-seg flush: writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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g := w.gsoWrites[0]
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if g.total() != 40+1000 {
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t.Errorf("super total=%d want %d", g.total(), 40+1000)
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}
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if g.payLen() != 1000 {
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t.Errorf("payLen=%d want 1000", g.payLen())
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}
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}
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func TestCoalescerCoalescesAdjacentACKs(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 1200)
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if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(2200, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(3400, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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if len(w.gsoWrites) != 1 {
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t.Fatalf("want 1 gso write, got %d (plain=%d)", len(w.gsoWrites), len(w.writes))
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}
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g := w.gsoWrites[0]
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if g.gsoSize != 1200 {
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t.Errorf("gsoSize=%d want 1200", g.gsoSize)
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}
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if len(g.hdr) != 40 {
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t.Errorf("hdrLen=%d want 40", len(g.hdr))
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}
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if g.csumStart != 20 {
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t.Errorf("csumStart=%d want 20", g.csumStart)
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}
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if len(g.pays) != 3 {
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t.Errorf("pay count=%d want 3", len(g.pays))
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}
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if g.total() != 40+3*1200 {
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t.Errorf("superpacket len=%d want %d", g.total(), 40+3*1200)
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}
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if tot := binary.BigEndian.Uint16(g.hdr[2:4]); int(tot) != g.total() {
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t.Errorf("ip total_length=%d want %d", tot, g.total())
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}
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}
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func TestCoalescerRejectsSeqGap(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 1200)
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if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(3000, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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// Each packet flushes as its own single-segment WriteGSO.
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if len(w.gsoWrites) != 2 || len(w.writes) != 0 {
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t.Fatalf("seq gap: want 2 gso writes got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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func TestCoalescerRejectsFlagMismatch(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 1200)
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if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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// SYN|ACK is non-admissible. Must flush matching flow's slot (gso)
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// and then plain-write the SYN packet itself.
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syn := buildTCPv4(2200, tcpSyn|tcpAck, pay)
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if err := c.Commit(syn); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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if len(w.writes) != 1 || len(w.gsoWrites) != 1 {
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t.Fatalf("flag mismatch: want 1 plain + 1 gso, got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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func TestCoalescerRejectsFIN(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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fin := buildTCPv4(1000, tcpAck|tcpFin, []byte("x"))
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if err := c.Commit(fin); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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// FIN isn't admissible — passthrough as plain, no slot, no gso.
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if len(w.writes) != 1 || len(w.gsoWrites) != 0 {
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t.Fatalf("FIN should be passthrough, got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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func TestCoalescerShortLastSegmentClosesChain(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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full := make([]byte, 1200)
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half := make([]byte, 500)
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if err := c.Commit(buildTCPv4(1000, tcpAck, full)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(2200, tcpAck, half)); err != nil {
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t.Fatal(err)
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}
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// Chain now closed; next packet seeds a new slot on the same flow
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// after flushing the old one.
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if err := c.Commit(buildTCPv4(2700, tcpAck, full)); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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// Expect two gso writes: the first two packets coalesced, then the
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// third flushed alone (single-seg via GSO_NONE).
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if len(w.gsoWrites) != 2 {
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t.Fatalf("want 2 gso writes got %d", len(w.gsoWrites))
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}
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if len(w.writes) != 0 {
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t.Fatalf("want 0 plain writes got %d", len(w.writes))
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}
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if w.gsoWrites[0].gsoSize != 1200 {
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t.Errorf("gsoSize=%d want 1200", w.gsoWrites[0].gsoSize)
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}
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if got, want := w.gsoWrites[0].total(), 40+1200+500; got != want {
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t.Errorf("super len=%d want %d", got, want)
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}
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}
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func TestCoalescerPSHFinalizesChain(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 1200)
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if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(2200, tcpAckPsh, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(3400, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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// First two coalesce; the third seeds a fresh slot that flushes alone.
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if len(w.gsoWrites) != 2 {
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t.Fatalf("want 2 gso writes got %d", len(w.gsoWrites))
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}
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if len(w.writes) != 0 {
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t.Fatalf("want 0 plain writes got %d", len(w.writes))
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}
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}
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// TestCoalescerPropagatesPSHFromAppended ensures that when an appended
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// segment carries PSH (or is short, sealing the chain), the PSH bit ends
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// up in the emitted superpacket's TCP flags. The kernel TSO path keeps
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// PSH only on the last segment iff the input header has it set; if the
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// coalescer drops it the sender's push signal never reaches the receiver.
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func TestCoalescerPropagatesPSHFromAppended(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 1200)
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// Seed has no PSH; second segment carries PSH and seals the chain.
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if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildTCPv4(2200, tcpAckPsh, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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if len(w.gsoWrites) != 1 {
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t.Fatalf("want 1 gso write got %d", len(w.gsoWrites))
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}
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g := w.gsoWrites[0]
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const ipHdrLen = 20
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flags := g.hdr[ipHdrLen+13]
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if flags&tcpPsh == 0 {
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t.Fatalf("PSH lost from coalesced superpacket: flags=0x%02x", flags)
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}
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if flags&tcpAck == 0 {
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t.Fatalf("ACK missing from coalesced superpacket: flags=0x%02x", flags)
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}
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}
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func TestCoalescerRejectsDifferentFlow(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 1200)
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p1 := buildTCPv4(1000, tcpAck, pay)
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p2 := buildTCPv4(2200, tcpAck, pay)
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binary.BigEndian.PutUint16(p2[20:22], 9999)
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if err := c.Commit(p1); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(p2); err != nil {
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t.Fatal(err)
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}
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if err := c.Flush(); err != nil {
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t.Fatal(err)
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}
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// Two independent flows, each flushes its own single-segment WriteGSO.
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if len(w.gsoWrites) != 2 || len(w.writes) != 0 {
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t.Fatalf("diff flow: want 2 gso writes got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
|
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|
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func TestCoalescerRejectsIPOptions(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewTCPCoalescer(w)
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pay := make([]byte, 500)
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pkt := buildTCPv4(1000, tcpAck, pay)
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// Bump IHL to 6 to simulate 4 bytes of IP options. Don't actually add
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|
// bytes — parser should bail before it matters.
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pkt[0] = 0x46
|
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if err := c.Commit(pkt); err != nil {
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t.Fatal(err)
|
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}
|
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if err := c.Flush(); err != nil {
|
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t.Fatal(err)
|
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}
|
|
// Non-admissible parse → passthrough as plain.
|
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if len(w.writes) != 1 || len(w.gsoWrites) != 0 {
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t.Fatalf("IP options should passthrough, got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
|
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}
|
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}
|
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|
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func TestCoalescerCapBySegments(t *testing.T) {
|
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w := &fakeTunWriter{gsoEnabled: true}
|
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c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 512)
|
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seq := uint32(1000)
|
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for i := 0; i < tcpCoalesceMaxSegs+5; i++ {
|
|
if err := c.Commit(buildTCPv4(seq, tcpAck, pay)); err != nil {
|
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t.Fatal(err)
|
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}
|
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seq += uint32(len(pay))
|
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}
|
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if err := c.Flush(); err != nil {
|
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t.Fatal(err)
|
|
}
|
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for _, g := range w.gsoWrites {
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segs := len(g.pays)
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if segs > tcpCoalesceMaxSegs {
|
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t.Fatalf("super exceeded seg cap: %d > %d", segs, tcpCoalesceMaxSegs)
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}
|
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}
|
|
}
|
|
|
|
// TestCoalescerMultipleFlowsInSameBatch proves two interleaved bulk TCP
|
|
// flows coalesce independently in a single Flush.
|
|
func TestCoalescerMultipleFlowsInSameBatch(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
|
|
// Flow A: sport 1000. Flow B: sport 3000.
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 100, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 500, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 1300, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 1700, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 2500, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 2900, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 gso writes (one per flow), got %d", len(w.gsoWrites))
|
|
}
|
|
if len(w.writes) != 0 {
|
|
t.Fatalf("want no plain writes, got %d", len(w.writes))
|
|
}
|
|
// Each superpacket should carry 3 segments.
|
|
for i, g := range w.gsoWrites {
|
|
if len(g.pays) != 3 {
|
|
t.Errorf("gso[%d]: segs=%d want 3", i, len(g.pays))
|
|
}
|
|
if g.gsoSize != 1200 {
|
|
t.Errorf("gso[%d]: gsoSize=%d want 1200", i, g.gsoSize)
|
|
}
|
|
}
|
|
// Verify each superpacket carries the source port it was seeded with.
|
|
seenSports := map[uint16]bool{}
|
|
for _, g := range w.gsoWrites {
|
|
sp := binary.BigEndian.Uint16(g.hdr[20:22])
|
|
seenSports[sp] = true
|
|
}
|
|
if !seenSports[1000] || !seenSports[3000] {
|
|
t.Errorf("expected superpackets for sports 1000 and 3000, got %v", seenSports)
|
|
}
|
|
}
|
|
|
|
// TestCoalescerPreservesArrivalOrder confirms that with passthrough and
|
|
// coalesced events both queued, Flush emits them in Add order rather than
|
|
// writing passthrough packets synchronously.
|
|
func TestCoalescerPreservesArrivalOrder(t *testing.T) {
|
|
w := &orderedFakeWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
// Sequence: coalesceable TCP, ICMP (passthrough), coalesceable TCP on
|
|
// a different flow. Expected emit order: gso(X), plain(ICMP), gso(Y).
|
|
pay := make([]byte, 1200)
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 100, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
icmp := make([]byte, 28)
|
|
icmp[0] = 0x45
|
|
binary.BigEndian.PutUint16(icmp[2:4], 28)
|
|
icmp[9] = 1
|
|
copy(icmp[12:16], []byte{10, 0, 0, 1})
|
|
copy(icmp[16:20], []byte{10, 0, 0, 3})
|
|
if err := c.Commit(icmp); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 500, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Nothing should have hit the writer synchronously.
|
|
if len(w.events) != 0 {
|
|
t.Fatalf("Add emitted events synchronously: %v", w.events)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if got, want := w.events, []string{"gso", "plain", "gso"}; !stringSliceEq(got, want) {
|
|
t.Fatalf("flush order=%v want %v", got, want)
|
|
}
|
|
}
|
|
|
|
// orderedFakeWriter records only the sequence of call types so tests can
|
|
// assert arrival order without inspecting bytes.
|
|
type orderedFakeWriter struct {
|
|
gsoEnabled bool
|
|
events []string
|
|
}
|
|
|
|
func (w *orderedFakeWriter) Write(p []byte) (int, error) {
|
|
w.events = append(w.events, "plain")
|
|
return len(p), nil
|
|
}
|
|
|
|
func (w *orderedFakeWriter) WriteGSO(hdr []byte, transportHdr []byte, pays [][]byte, _ tio.GSOProto) error {
|
|
w.events = append(w.events, "gso")
|
|
return nil
|
|
}
|
|
|
|
func (w *orderedFakeWriter) Capabilities() tio.Capabilities {
|
|
return tio.Capabilities{TSO: w.gsoEnabled, USO: w.gsoEnabled}
|
|
}
|
|
|
|
func stringSliceEq(a, b []string) bool {
|
|
if len(a) != len(b) {
|
|
return false
|
|
}
|
|
for i := range a {
|
|
if a[i] != b[i] {
|
|
return false
|
|
}
|
|
}
|
|
return true
|
|
}
|
|
|
|
// TestCoalescerInterleavedFlowsPreserveOrdering checks that a non-admissible
|
|
// packet (SYN) mid-flow only flushes its own flow, not others.
|
|
func TestCoalescerInterleavedFlowsPreserveOrdering(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
|
|
// Flow A two segments.
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 100, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 1300, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Flow B two segments.
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 500, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 1700, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Flow A SYN (non-admissible) — must flush only flow A's slot.
|
|
syn := buildTCPv4Ports(1000, 2000, 9999, tcpSyn|tcpAck, pay)
|
|
if err := c.Commit(syn); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Flow B continues — should still be coalesced with its seed.
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 2900, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
|
|
// Expected:
|
|
// - 1 gso for flow A (first 2 segments)
|
|
// - 1 plain for flow A SYN
|
|
// - 1 gso for flow B (3 segments)
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 gso writes, got %d", len(w.gsoWrites))
|
|
}
|
|
if len(w.writes) != 1 {
|
|
t.Fatalf("want 1 plain write (SYN), got %d", len(w.writes))
|
|
}
|
|
// Find the 3-segment gso (flow B) and the 2-segment gso (flow A).
|
|
var segCounts []int
|
|
for _, g := range w.gsoWrites {
|
|
segCounts = append(segCounts, len(g.pays))
|
|
}
|
|
if !(segCounts[0] == 2 && segCounts[1] == 3) && !(segCounts[0] == 3 && segCounts[1] == 2) {
|
|
t.Errorf("unexpected segment counts: %v (want 2 and 3)", segCounts)
|
|
}
|
|
}
|
|
|
|
// ECN test helpers and constants.
|
|
|
|
const (
|
|
tcpEce = 0x40
|
|
tcpCwr = 0x80
|
|
|
|
// 2-bit IP-level ECN codepoints (lower 2 bits of IPv4 ToS / IPv6 TC).
|
|
ecnNotECT = 0x00
|
|
ecnECT1 = 0x01
|
|
ecnECT0 = 0x02
|
|
ecnCE = 0x03
|
|
)
|
|
|
|
// buildTCPv4WithToS is buildTCPv4 with caller-specified IPv4 ToS so tests can
|
|
// drive DSCP and ECN bits.
|
|
func buildTCPv4WithToS(tos byte, seq uint32, flags byte, payload []byte) []byte {
|
|
pkt := buildTCPv4(seq, flags, payload)
|
|
pkt[1] = tos
|
|
return pkt
|
|
}
|
|
|
|
// buildTCPv6 mirrors buildTCPv4 for IPv6. tcLow is the low 4 bits of Traffic
|
|
// Class, which carries the ECN codepoint (mask 0x03) and the bottom 2 DSCP
|
|
// bits — enough to drive the ECN paths under test.
|
|
func buildTCPv6(tcLow byte, seq uint32, flags byte, payload []byte) []byte {
|
|
const ipHdrLen = 40
|
|
const tcpHdrLen = 20
|
|
pkt := make([]byte, ipHdrLen+tcpHdrLen+len(payload))
|
|
|
|
pkt[0] = 0x60 // version=6, TC[7:4]=0
|
|
pkt[1] = (tcLow & 0x0f) << 4 // TC[3:0] in high nibble; flow=0
|
|
binary.BigEndian.PutUint16(pkt[4:6], uint16(tcpHdrLen+len(payload)))
|
|
pkt[6] = ipProtoTCP
|
|
pkt[7] = 64
|
|
copy(pkt[8:24], []byte{0xfd, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1})
|
|
copy(pkt[24:40], []byte{0xfd, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2})
|
|
|
|
binary.BigEndian.PutUint16(pkt[40:42], 1000)
|
|
binary.BigEndian.PutUint16(pkt[42:44], 2000)
|
|
binary.BigEndian.PutUint32(pkt[44:48], seq)
|
|
binary.BigEndian.PutUint32(pkt[48:52], 12345)
|
|
pkt[52] = 0x50
|
|
pkt[53] = flags
|
|
binary.BigEndian.PutUint16(pkt[54:56], 0xffff)
|
|
|
|
copy(pkt[60:], payload)
|
|
return pkt
|
|
}
|
|
|
|
// TestCoalescerCoalescesEceFlow confirms that ECN-Echo-marked ACKs (an
|
|
// ECN-aware flow under congestion) keep getting coalesced into a TSO
|
|
// superpacket instead of falling out to passthrough, and that the seed
|
|
// retains ECE on the wire.
|
|
func TestCoalescerCoalescesEceFlow(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
flags := byte(tcpAck | tcpEce)
|
|
if err := c.Commit(buildTCPv4(1000, flags, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(2200, flags, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 1 {
|
|
t.Fatalf("want 1 gso write, got %d (plain=%d)", len(w.gsoWrites), len(w.writes))
|
|
}
|
|
g := w.gsoWrites[0]
|
|
if len(g.pays) != 2 {
|
|
t.Errorf("pay count=%d want 2", len(g.pays))
|
|
}
|
|
if seedFlags := g.hdr[20+13]; seedFlags&tcpEce == 0 {
|
|
t.Errorf("seed flags=0x%02x want ECE preserved", seedFlags)
|
|
}
|
|
}
|
|
|
|
// TestCoalescerCwrSealsFlow confirms that a CWR-bearing segment in the
|
|
// middle of a flow goes to passthrough and seals the open slot, so a later
|
|
// in-flow segment seeds a new slot rather than extending the prior burst.
|
|
func TestCoalescerCwrSealsFlow(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(2200, tcpAck|tcpCwr, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(3400, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.writes) != 1 {
|
|
t.Fatalf("want 1 plain write (CWR), got %d", len(w.writes))
|
|
}
|
|
// Two GSO writes: the first seed before CWR, and a fresh seed after.
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 gso writes, got %d", len(w.gsoWrites))
|
|
}
|
|
for i, g := range w.gsoWrites {
|
|
if len(g.pays) != 1 {
|
|
t.Errorf("gso %d pay count=%d want 1", i, len(g.pays))
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestCoalescerEceMismatchReseeds confirms that toggling ECE mid-flow does
|
|
// not silently merge — receivers expect ECE either set on every segment of
|
|
// a CE-echoing window or none.
|
|
func TestCoalescerEceMismatchReseeds(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
if err := c.Commit(buildTCPv4(1000, tcpAck|tcpEce, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(2200, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 separate seeds, got %d gso writes", len(w.gsoWrites))
|
|
}
|
|
for i, g := range w.gsoWrites {
|
|
if len(g.pays) != 1 {
|
|
t.Errorf("gso %d pay count=%d want 1", i, len(g.pays))
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestCoalescerMergesCEMark confirms that an ECT(0) burst with a single
|
|
// CE-marked packet still coalesces, and the merged superpacket carries CE.
|
|
func TestCoalescerMergesCEMark(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
if err := c.Commit(buildTCPv4WithToS(ecnECT0, 1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Router along the path stamped CE on this one.
|
|
if err := c.Commit(buildTCPv4WithToS(ecnCE, 2200, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4WithToS(ecnECT0, 3400, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 1 {
|
|
t.Fatalf("want 1 merged gso write, got %d (plain=%d)", len(w.gsoWrites), len(w.writes))
|
|
}
|
|
g := w.gsoWrites[0]
|
|
if len(g.pays) != 3 {
|
|
t.Errorf("pay count=%d want 3", len(g.pays))
|
|
}
|
|
if got := g.hdr[1] & 0x03; got != ecnCE {
|
|
t.Errorf("seed ECN=0x%02x want CE 0x%02x", got, ecnCE)
|
|
}
|
|
}
|
|
|
|
// TestCoalescerDscpMismatchReseeds confirms that the new ECN-mask in
|
|
// headersMatch did not also relax DSCP — different DSCP must still split.
|
|
func TestCoalescerDscpMismatchReseeds(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
// Same ECN (Not-ECT), different DSCP (0x10 vs 0x20 in upper 6 bits).
|
|
tosA := byte(0x10<<2) | ecnNotECT
|
|
tosB := byte(0x20<<2) | ecnNotECT
|
|
if err := c.Commit(buildTCPv4WithToS(tosA, 1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4WithToS(tosB, 2200, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 separate seeds (different DSCP), got %d", len(w.gsoWrites))
|
|
}
|
|
}
|
|
|
|
// TestCoalescerIPv6CoalescesEceFlow is the IPv6 analogue of
|
|
// TestCoalescerCoalescesEceFlow.
|
|
func TestCoalescerIPv6CoalescesEceFlow(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
flags := byte(tcpAck | tcpEce)
|
|
if err := c.Commit(buildTCPv6(0, 1000, flags, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv6(0, 2200, flags, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 1 {
|
|
t.Fatalf("want 1 gso write, got %d", len(w.gsoWrites))
|
|
}
|
|
g := w.gsoWrites[0]
|
|
if seedFlags := g.hdr[40+13]; seedFlags&tcpEce == 0 {
|
|
t.Errorf("seed flags=0x%02x want ECE preserved", seedFlags)
|
|
}
|
|
}
|
|
|
|
// TestCoalescerSortsReorderedSeedsAndMerges feeds three same-flow MSS
|
|
// segments out of TCP-seq order (mimicking a wire reorder that escaped
|
|
// the rxOrder per-batch sort). Without the reorderForFlush sort+merge,
|
|
// each out-of-seq arrival would seed its own slot and the slots would
|
|
// emit in arrival order, producing a kernel-visible TCP reorder. With
|
|
// the sort+merge, the three slots are sorted by seq and folded back into
|
|
// one in-order TSO superpacket — same shape the receiver TCP would have
|
|
// seen had the wire never reordered.
|
|
func TestCoalescerSortsReorderedSeedsAndMerges(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
// Arrival order: seq 1000, 3400, 2200. The 3400 seeds a separate slot
|
|
// because 3400 != nextSeq=2200, then 2200 fails to extend the 3400 slot
|
|
// and seeds its own. Three slots end up in c.slots; reorderForFlush
|
|
// should sort them into [1000,2200,3400] and merge them back into one.
|
|
if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(3400, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(2200, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 1 {
|
|
t.Fatalf("want 1 merged gso write got %d", len(w.gsoWrites))
|
|
}
|
|
g := w.gsoWrites[0]
|
|
if len(g.pays) != 3 {
|
|
t.Fatalf("merged segs=%d want 3", len(g.pays))
|
|
}
|
|
const ipHdrLen = 20
|
|
if seedSeq := binary.BigEndian.Uint32(g.hdr[ipHdrLen+4 : ipHdrLen+8]); seedSeq != 1000 {
|
|
t.Errorf("merged seed seq=%d want 1000 (lowest)", seedSeq)
|
|
}
|
|
}
|
|
|
|
// TestCoalescerSortAcrossFlowsMergesEachIndependently checks that two
|
|
// flows interleaved with reorder are each sorted-and-merged in isolation
|
|
// without any cross-flow contamination.
|
|
func TestCoalescerSortAcrossFlowsMergesEachIndependently(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
// Flow A (sport 1000) seq 100, 1300; flow B (sport 3000) seq 500, 1700.
|
|
// Arrival: A.1300, B.1700, A.100, B.500 — every flow reordered.
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 1300, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 1700, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(1000, 2000, 100, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4Ports(3000, 2000, 500, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 gso writes (one per flow merged), got %d", len(w.gsoWrites))
|
|
}
|
|
for i, g := range w.gsoWrites {
|
|
if len(g.pays) != 2 {
|
|
t.Errorf("gso[%d] segs=%d want 2", i, len(g.pays))
|
|
}
|
|
const ipHdrLen = 20
|
|
seedSeq := binary.BigEndian.Uint32(g.hdr[ipHdrLen+4 : ipHdrLen+8])
|
|
sport := binary.BigEndian.Uint16(g.hdr[ipHdrLen : ipHdrLen+2])
|
|
// Each flow's merged seed should be the LOWER of its two seqs.
|
|
switch sport {
|
|
case 1000:
|
|
if seedSeq != 100 {
|
|
t.Errorf("flow A seed seq=%d want 100", seedSeq)
|
|
}
|
|
case 3000:
|
|
if seedSeq != 500 {
|
|
t.Errorf("flow B seed seq=%d want 500", seedSeq)
|
|
}
|
|
default:
|
|
t.Errorf("unexpected sport %d", sport)
|
|
}
|
|
}
|
|
}
|
|
|
|
// TestCoalescerSortKeepsPSHBoundary verifies that a PSH-sealed slot is
|
|
// not folded into a later seq-contiguous slot — PSH placement is part of
|
|
// the wire signal and merging across it would shift the receiver's push
|
|
// boundary by an arbitrary number of segments.
|
|
func TestCoalescerSortKeepsPSHBoundary(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
// Seq 1000 (no PSH) + 2200 (PSH) → seal one slot with PSH set.
|
|
// Seq 3400 (no PSH) is contiguous to 3400 from seq 2200+1200; without
|
|
// the PSH check it would merge in.
|
|
if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(2200, tcpAckPsh, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(3400, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 2 {
|
|
t.Fatalf("want 2 gso writes (PSH-sealed and fresh seed), got %d", len(w.gsoWrites))
|
|
}
|
|
}
|
|
|
|
// TestCoalescerSortKeepsPassthroughBarrier confirms a passthrough slot in
|
|
// the middle of the queue prevents the post-sort merge from folding
|
|
// across it. Reordered same-flow data on either side of the passthrough
|
|
// is sorted/merged independently.
|
|
func TestCoalescerSortKeepsPassthroughBarrier(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
// First two segments seed S1 (then a 3400 reorder seeds S2).
|
|
if err := c.Commit(buildTCPv4(1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv4(3400, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Non-coalesceable packet (SYN+ACK) flushes S1's openSlots entry and
|
|
// becomes a passthrough barrier in c.slots.
|
|
if err := c.Commit(buildTCPv4(9999, tcpSyn|tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// Post-barrier same-flow data: should never end up before the SYN.
|
|
if err := c.Commit(buildTCPv4(2200, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
// We expect: gso(merged 1000+3400 ranges sorted but not contiguous so 2
|
|
// gso writes), plain(SYN), gso(2200 alone). The pre-barrier sort should
|
|
// land 1000 before 3400, and the post-barrier 2200 stays after the SYN.
|
|
if len(w.writes) != 1 {
|
|
t.Fatalf("want 1 plain SYN passthrough, got %d", len(w.writes))
|
|
}
|
|
}
|
|
|
|
// TestCoalescerIPv6MergesCEMark is the IPv6 analogue of
|
|
// TestCoalescerMergesCEMark. ECN bits live in TC[1:0] = byte 1 mask 0x30.
|
|
func TestCoalescerIPv6MergesCEMark(t *testing.T) {
|
|
w := &fakeTunWriter{gsoEnabled: true}
|
|
c := NewTCPCoalescer(w)
|
|
pay := make([]byte, 1200)
|
|
// tcLow is the low 4 bits of TC; ECN occupies the bottom 2 of those.
|
|
if err := c.Commit(buildTCPv6(ecnECT0, 1000, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Commit(buildTCPv6(ecnCE, 2200, tcpAck, pay)); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if err := c.Flush(); err != nil {
|
|
t.Fatal(err)
|
|
}
|
|
if len(w.gsoWrites) != 1 {
|
|
t.Fatalf("want 1 merged gso write, got %d", len(w.gsoWrites))
|
|
}
|
|
g := w.gsoWrites[0]
|
|
// Byte 1 high nibble holds TC[3:0]; ECN is the low 2 bits of that nibble,
|
|
// which appears in byte 1 mask 0x30 (>>4 to read the codepoint value).
|
|
if got := (g.hdr[1] >> 4) & 0x03; got != ecnCE {
|
|
t.Errorf("seed v6 ECN=0x%02x want CE 0x%02x", got, ecnCE)
|
|
}
|
|
}
|