mirror of
https://github.com/slackhq/nebula.git
synced 2026-05-16 12:57:38 +02:00
384 lines
11 KiB
Go
384 lines
11 KiB
Go
package batch
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import (
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"encoding/binary"
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"testing"
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)
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// buildUDPv4 builds a minimal IPv4+UDP packet with the given payload and ports.
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func buildUDPv4(sport, dport uint16, payload []byte) []byte {
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const ipHdrLen = 20
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const udpHdrLen = 8
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total := ipHdrLen + udpHdrLen + 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] = ipProtoUDP
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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.PutUint16(pkt[24:26], uint16(udpHdrLen+len(payload)))
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binary.BigEndian.PutUint16(pkt[26:28], 0)
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copy(pkt[28:], payload)
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return pkt
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}
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// buildUDPv6 builds a minimal IPv6+UDP packet.
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func buildUDPv6(sport, dport uint16, payload []byte) []byte {
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const ipHdrLen = 40
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const udpHdrLen = 8
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total := ipHdrLen + udpHdrLen + len(payload)
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pkt := make([]byte, total)
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pkt[0] = 0x60
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binary.BigEndian.PutUint16(pkt[4:6], uint16(udpHdrLen+len(payload)))
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pkt[6] = ipProtoUDP
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pkt[7] = 64
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pkt[8] = 0xfe
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pkt[9] = 0x80
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pkt[23] = 1
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pkt[24] = 0xfe
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pkt[25] = 0x80
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pkt[39] = 2
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binary.BigEndian.PutUint16(pkt[40:42], sport)
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binary.BigEndian.PutUint16(pkt[42:44], dport)
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binary.BigEndian.PutUint16(pkt[44:46], uint16(udpHdrLen+len(payload)))
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binary.BigEndian.PutUint16(pkt[46:48], 0)
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copy(pkt[48:], payload)
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return pkt
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}
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func TestUDPCoalescerPassthroughWhenGSOUnavailable(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: false}
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c := NewUDPCoalescer(w)
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pkt := buildUDPv4(1000, 53, make([]byte, 100))
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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("no Add-time writes: 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 TestUDPCoalescerNonUDPPassthrough(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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// ICMP packet
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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 must pass through unchanged: writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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func TestUDPCoalescerSeedThenFlushAlone(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pkt := buildUDPv4(1000, 53, make([]byte, 800))
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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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// Single-segment flush goes through WriteGSO; the writer infers GSO_NONE
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// from len(pays)==1 and the kernel fills in the UDP csum (NEEDS_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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}
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func TestUDPCoalescerCoalescesEqualSized(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pay := make([]byte, 1200)
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for i := 0; i < 3; i++ {
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if err := c.Commit(buildUDPv4(1000, 53, pay)); err != nil {
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t.Fatal(err)
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}
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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.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.csumStart != 20 {
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t.Errorf("csumStart=%d want 20", g.csumStart)
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}
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// IP totalLen and UDP length must be the TOTAL across all segments —
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// the kernel's ip_rcv_core trims skbs to iph->tot_len, so a per-segment
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// value would silently drop everything but the first segment. Total =
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// IP(20) + UDP(8) + 3*1200 = 3628.
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gotTotalLen := binary.BigEndian.Uint16(g.hdr[2:4])
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if gotTotalLen != 3628 {
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t.Errorf("ipv4 total_len=%d want 3628 (must be total across segments)", gotTotalLen)
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}
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gotUDPLen := binary.BigEndian.Uint16(g.hdr[20+4 : 20+6])
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if gotUDPLen != 8+3*1200 {
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t.Errorf("udp len=%d want %d", gotUDPLen, 8+3*1200)
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}
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}
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// Last segment may be shorter, sealing the chain.
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func TestUDPCoalescerShortLastSegmentSeals(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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full := make([]byte, 1200)
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tail := make([]byte, 600)
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if err := c.Commit(buildUDPv4(1000, 53, full)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildUDPv4(1000, 53, full)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildUDPv4(1000, 53, tail)); err != nil {
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t.Fatal(err)
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}
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// A 4th packet, even same-sized, must NOT join — chain is sealed.
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if err := c.Commit(buildUDPv4(1000, 53, 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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if len(w.gsoWrites) != 2 {
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t.Fatalf("want 2 gso writes (sealed + new seed), got %d", len(w.gsoWrites))
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}
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if len(w.gsoWrites[0].pays) != 3 {
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t.Errorf("first super: want 3 pays, got %d", len(w.gsoWrites[0].pays))
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}
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if len(w.gsoWrites[1].pays) != 1 {
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t.Errorf("second super: want 1 pay (re-seed), got %d", len(w.gsoWrites[1].pays))
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}
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}
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// A larger-than-gsoSize packet cannot extend the slot — it reseeds.
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func TestUDPCoalescerLargerThanSeedReseeds(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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if err := c.Commit(buildUDPv4(1000, 53, make([]byte, 800))); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildUDPv4(1000, 53, make([]byte, 1200))); 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) != 2 {
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t.Fatalf("want 2 separate seeds, got %d", len(w.gsoWrites))
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}
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}
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// Different 5-tuples must not coalesce.
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func TestUDPCoalescerDifferentFlowsKeepSeparate(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pay := make([]byte, 800)
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if err := c.Commit(buildUDPv4(1000, 53, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildUDPv4(2000, 53, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildUDPv4(1000, 53, pay)); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(buildUDPv4(2000, 53, 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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// Two flows × 2 datagrams each = 2 superpackets of 2 segments.
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if len(w.gsoWrites) != 2 {
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t.Fatalf("want 2 gso writes (one per flow), got %d", len(w.gsoWrites))
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}
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for i, g := range w.gsoWrites {
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if len(g.pays) != 2 {
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t.Errorf("super %d: want 2 pays, got %d", i, len(g.pays))
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}
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}
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}
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// Caps at udpCoalesceMaxSegs.
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func TestUDPCoalescerCapsAtMaxSegs(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pay := make([]byte, 100)
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for i := 0; i < udpCoalesceMaxSegs+5; i++ {
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if err := c.Commit(buildUDPv4(1000, 53, pay)); err != nil {
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t.Fatal(err)
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}
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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 superpacket holds udpCoalesceMaxSegs segments; the spillover
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// reseeds a new one.
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if len(w.gsoWrites) != 2 {
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t.Fatalf("want 2 gso writes (cap then reseed), got %d", len(w.gsoWrites))
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}
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if len(w.gsoWrites[0].pays) != udpCoalesceMaxSegs {
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t.Errorf("first super: pays=%d want %d", len(w.gsoWrites[0].pays), udpCoalesceMaxSegs)
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}
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if len(w.gsoWrites[1].pays) != 5 {
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t.Errorf("second super: pays=%d want 5", len(w.gsoWrites[1].pays))
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}
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}
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// CE marks on appended segments must be merged into the seed's IP TOS.
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func TestUDPCoalescerMergesCEMark(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pay := make([]byte, 800)
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pkt0 := buildUDPv4(1000, 53, pay) // ECN=00
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pkt1 := buildUDPv4(1000, 53, pay)
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pkt1[1] = 0x03 // CE
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pkt2 := buildUDPv4(1000, 53, pay)
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if err := c.Commit(pkt0); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(pkt1); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(pkt2); 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 merged gso write, got %d (plain=%d)", len(w.gsoWrites), len(w.writes))
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}
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if w.gsoWrites[0].hdr[1]&0x03 != 0x03 {
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t.Errorf("CE not merged into seed (tos=%#x)", w.gsoWrites[0].hdr[1])
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}
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}
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// IPv6 path: same flow, equal-sized → coalesced.
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func TestUDPCoalescerIPv6Coalesces(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pay := make([]byte, 1200)
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for i := 0; i < 3; i++ {
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if err := c.Commit(buildUDPv6(1000, 53, pay)); err != nil {
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t.Fatal(err)
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}
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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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if !g.isV6 {
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t.Errorf("expected v6 write")
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}
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if g.csumStart != 40 {
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t.Errorf("csumStart=%d want 40", g.csumStart)
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}
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// IPv6 payload_len and UDP length must be TOTAL — kernel's
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// ip6_rcv_core trims to payload_len + ipv6 hdr size. Total UDP = 8 +
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// 3*1200 = 3608.
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gotPlen := binary.BigEndian.Uint16(g.hdr[4:6])
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if gotPlen != 8+3*1200 {
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t.Errorf("ipv6 payload_len=%d want %d (must be total)", gotPlen, 8+3*1200)
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}
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gotUDPLen := binary.BigEndian.Uint16(g.hdr[40+4 : 40+6])
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if gotUDPLen != 8+3*1200 {
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t.Errorf("udp len=%d want %d", gotUDPLen, 8+3*1200)
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}
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}
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// DSCP differences must reseed (headers don't match outside ECN).
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func TestUDPCoalescerDSCPMismatchReseeds(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pay := make([]byte, 800)
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pkt0 := buildUDPv4(1000, 53, pay)
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pkt1 := buildUDPv4(1000, 53, pay)
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pkt1[1] = 0xb8 // EF DSCP, ECN=0
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if err := c.Commit(pkt0); err != nil {
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t.Fatal(err)
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}
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if err := c.Commit(pkt1); 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) != 2 {
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t.Fatalf("want 2 separate seeds (different DSCP), got %d", len(w.gsoWrites))
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}
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}
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// Fragmented IPv4 must not be coalesced.
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func TestUDPCoalescerFragmentedIPv4PassesThrough(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pkt := buildUDPv4(1000, 53, make([]byte, 200))
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binary.BigEndian.PutUint16(pkt[6:8], 0x2000) // MF=1
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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("frag must pass through plain, got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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// IPv4 with options is not admissible (we require IHL=5).
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func TestUDPCoalescerIPv4WithOptionsPassesThrough(t *testing.T) {
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w := &fakeTunWriter{gsoEnabled: true}
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c := NewUDPCoalescer(w)
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pkt := buildUDPv4(1000, 53, make([]byte, 200))
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pkt[0] = 0x46 // IHL = 6 (24-byte IPv4 header — has options)
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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("ipv4-with-options must pass through plain, got writes=%d gso=%d", len(w.writes), len(w.gsoWrites))
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}
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}
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