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tailscale/net/art/table_test.go
David Anderson e92adfe5e4 net/art: allow non-pointers as values 
Values are still turned into pointers internally to maintain the
invariants of strideTable, but from the user's perspective it's
now possible to tbl.Insert(pfx, true) rather than
tbl.Insert(pfx, ptr.To(true)).

Updates #7781

Signed-off-by: David Anderson <danderson@tailscale.com>
2023-08-17 10:43:18 -07:00

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// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
package art
import (
crand "crypto/rand"
"fmt"
"math/rand"
"net/netip"
"runtime"
"strconv"
"testing"
"time"
)
func TestRegression(t *testing.T) {
// These tests are specific triggers for subtle correctness issues
// that came up during initial implementation. Even if they seem
// arbitrary, please do not clean them up. They are checking edge
// cases that are very easy to get wrong, and quite difficult for
// the other statistical tests to trigger promptly.
t.Run("prefixes_aligned_on_stride_boundary", func(t *testing.T) {
// Regression test for computePrefixSplit called with equal
// arguments.
tbl := &Table[int]{}
slow := slowPrefixTable[int]{}
p := netip.MustParsePrefix
tbl.Insert(p("226.205.197.0/24"), 1)
slow.insert(p("226.205.197.0/24"), 1)
tbl.Insert(p("226.205.0.0/16"), 2)
slow.insert(p("226.205.0.0/16"), 2)
probe := netip.MustParseAddr("226.205.121.152")
got, gotOK := tbl.Get(probe)
want, wantOK := slow.get(probe)
if !getsEqual(got, gotOK, want, wantOK) {
t.Fatalf("got (%v, %v), want (%v, %v)", got, gotOK, want, wantOK)
}
})
t.Run("parent_prefix_inserted_in_different_orders", func(t *testing.T) {
// Regression test for the off-by-one correction applied
// within computePrefixSplit.
t1, t2 := &Table[int]{}, &Table[int]{}
p := netip.MustParsePrefix
t1.Insert(p("136.20.0.0/16"), 1)
t1.Insert(p("136.20.201.62/32"), 2)
t2.Insert(p("136.20.201.62/32"), 2)
t2.Insert(p("136.20.0.0/16"), 1)
a := netip.MustParseAddr("136.20.54.139")
got1, ok1 := t1.Get(a)
got2, ok2 := t2.Get(a)
if !getsEqual(got1, ok1, got2, ok2) {
t.Errorf("Get(%q) is insertion order dependent: t1=(%v, %v), t2=(%v, %v)", a, got1, ok1, got2, ok2)
}
})
}
func TestComputePrefixSplit(t *testing.T) {
// These tests are partially redundant with other tests. Please
// keep them anyway. computePrefixSplit's behavior is remarkably
// subtle, and all the test cases listed below come from
// hard-earned debugging of malformed route tables.
var tests = []struct {
// prefixA can be a /8, /16 or /24 (v4).
// prefixB can be anything /9 or more specific.
prefixA, prefixB string
lastCommon string
aStride, bStride uint8
}{
{"192.168.1.0/24", "192.168.5.5/32", "192.168.0.0/16", 1, 5},
{"192.168.129.0/24", "192.168.128.0/17", "192.168.0.0/16", 129, 128},
{"192.168.5.0/24", "192.168.0.0/16", "192.0.0.0/8", 168, 168},
{"192.168.0.0/16", "192.168.0.0/16", "192.0.0.0/8", 168, 168},
{"ff:aaaa:aaaa::1/128", "ff:aaaa::/120", "ff:aaaa::/32", 170, 0},
}
for _, test := range tests {
a, b := netip.MustParsePrefix(test.prefixA), netip.MustParsePrefix(test.prefixB)
gotLastCommon, gotAStride, gotBStride := computePrefixSplit(a, b)
if want := netip.MustParsePrefix(test.lastCommon); gotLastCommon != want || gotAStride != test.aStride || gotBStride != test.bStride {
t.Errorf("computePrefixSplit(%q, %q) = %s, %d, %d; want %s, %d, %d", a, b, gotLastCommon, gotAStride, gotBStride, want, test.aStride, test.bStride)
}
}
}
func TestInsert(t *testing.T) {
tbl := &Table[int]{}
p := netip.MustParsePrefix
// Create a new leaf strideTable, with compressed path
tbl.Insert(p("192.168.0.1/32"), 1)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", -1},
{"192.168.0.3", -1},
{"192.168.0.255", -1},
{"192.168.1.1", -1},
{"192.170.1.1", -1},
{"192.180.0.1", -1},
{"192.180.3.5", -1},
{"10.0.0.5", -1},
{"10.0.0.15", -1},
})
// Insert into previous leaf, no tree changes
tbl.Insert(p("192.168.0.2/32"), 2)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", -1},
{"192.168.0.255", -1},
{"192.168.1.1", -1},
{"192.170.1.1", -1},
{"192.180.0.1", -1},
{"192.180.3.5", -1},
{"10.0.0.5", -1},
{"10.0.0.15", -1},
})
// Insert into previous leaf, unaligned prefix covering the /32s
tbl.Insert(p("192.168.0.0/26"), 7)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", -1},
{"192.168.1.1", -1},
{"192.170.1.1", -1},
{"192.180.0.1", -1},
{"192.180.3.5", -1},
{"10.0.0.5", -1},
{"10.0.0.15", -1},
})
// Create a different leaf elsewhere
tbl.Insert(p("10.0.0.0/27"), 3)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", -1},
{"192.168.1.1", -1},
{"192.170.1.1", -1},
{"192.180.0.1", -1},
{"192.180.3.5", -1},
{"10.0.0.5", 3},
{"10.0.0.15", 3},
})
// Insert that creates a new intermediate table and a new child
tbl.Insert(p("192.168.1.1/32"), 4)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", -1},
{"192.168.1.1", 4},
{"192.170.1.1", -1},
{"192.180.0.1", -1},
{"192.180.3.5", -1},
{"10.0.0.5", 3},
{"10.0.0.15", 3},
})
// Insert that creates a new intermediate table but no new child
tbl.Insert(p("192.170.0.0/16"), 5)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", -1},
{"192.168.1.1", 4},
{"192.170.1.1", 5},
{"192.180.0.1", -1},
{"192.180.3.5", -1},
{"10.0.0.5", 3},
{"10.0.0.15", 3},
})
// New leaf in a different subtree, so the next insert can test a
// variant of decompression.
tbl.Insert(p("192.180.0.1/32"), 8)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", -1},
{"192.168.1.1", 4},
{"192.170.1.1", 5},
{"192.180.0.1", 8},
{"192.180.3.5", -1},
{"10.0.0.5", 3},
{"10.0.0.15", 3},
})
// Insert that creates a new intermediate table but no new child,
// with an unaligned intermediate
tbl.Insert(p("192.180.0.0/21"), 9)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", -1},
{"192.168.1.1", 4},
{"192.170.1.1", 5},
{"192.180.0.1", 8},
{"192.180.3.5", 9},
{"10.0.0.5", 3},
{"10.0.0.15", 3},
})
// Insert a default route, those have their own codepath.
tbl.Insert(p("0.0.0.0/0"), 6)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.168.0.3", 7},
{"192.168.0.255", 6},
{"192.168.1.1", 4},
{"192.170.1.1", 5},
{"192.180.0.1", 8},
{"192.180.3.5", 9},
{"10.0.0.5", 3},
{"10.0.0.15", 3},
})
// Now all of the above again, but for IPv6.
// Create a new leaf strideTable, with compressed path
tbl.Insert(p("ff:aaaa::1/128"), 1)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", -1},
{"ff:aaaa::3", -1},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", -1},
{"ff:aaaa:aaaa:bbbb::1", -1},
{"ff:cccc::1", -1},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", -1},
{"ffff:bbbb::15", -1},
})
// Insert into previous leaf, no tree changes
tbl.Insert(p("ff:aaaa::2/128"), 2)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", -1},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", -1},
{"ff:aaaa:aaaa:bbbb::1", -1},
{"ff:cccc::1", -1},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", -1},
{"ffff:bbbb::15", -1},
})
// Insert into previous leaf, unaligned prefix covering the /128s
tbl.Insert(p("ff:aaaa::/125"), 7)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", -1},
{"ff:aaaa:aaaa:bbbb::1", -1},
{"ff:cccc::1", -1},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", -1},
{"ffff:bbbb::15", -1},
})
// Create a different leaf elsewhere
tbl.Insert(p("ffff:bbbb::/120"), 3)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", -1},
{"ff:aaaa:aaaa:bbbb::1", -1},
{"ff:cccc::1", -1},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", 3},
{"ffff:bbbb::15", 3},
})
// Insert that creates a new intermediate table and a new child
tbl.Insert(p("ff:aaaa:aaaa::1/128"), 4)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", 4},
{"ff:aaaa:aaaa:bbbb::1", -1},
{"ff:cccc::1", -1},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", 3},
{"ffff:bbbb::15", 3},
})
// Insert that creates a new intermediate table but no new child
tbl.Insert(p("ff:aaaa:aaaa:bb00::/56"), 5)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", 4},
{"ff:aaaa:aaaa:bbbb::1", 5},
{"ff:cccc::1", -1},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", 3},
{"ffff:bbbb::15", 3},
})
// New leaf in a different subtree, so the next insert can test a
// variant of decompression.
tbl.Insert(p("ff:cccc::1/128"), 8)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", 4},
{"ff:aaaa:aaaa:bbbb::1", 5},
{"ff:cccc::1", 8},
{"ff:cccc::ff", -1},
{"ffff:bbbb::5", 3},
{"ffff:bbbb::15", 3},
})
// Insert that creates a new intermediate table but no new child,
// with an unaligned intermediate
tbl.Insert(p("ff:cccc::/37"), 9)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", -1},
{"ff:aaaa:aaaa::1", 4},
{"ff:aaaa:aaaa:bbbb::1", 5},
{"ff:cccc::1", 8},
{"ff:cccc::ff", 9},
{"ffff:bbbb::5", 3},
{"ffff:bbbb::15", 3},
})
// Insert a default route, those have their own codepath.
tbl.Insert(p("::/0"), 6)
checkRoutes(t, tbl, []tableTest{
{"ff:aaaa::1", 1},
{"ff:aaaa::2", 2},
{"ff:aaaa::3", 7},
{"ff:aaaa::255", 6},
{"ff:aaaa:aaaa::1", 4},
{"ff:aaaa:aaaa:bbbb::1", 5},
{"ff:cccc::1", 8},
{"ff:cccc::ff", 9},
{"ffff:bbbb::5", 3},
{"ffff:bbbb::15", 3},
})
}
func TestDelete(t *testing.T) {
t.Parallel()
p := netip.MustParsePrefix
t.Run("prefix_in_root", func(t *testing.T) {
// Add/remove prefix from root table.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("10.0.0.0/8"), 1)
checkRoutes(t, tbl, []tableTest{
{"10.0.0.1", 1},
{"255.255.255.255", -1},
})
checkSize(t, tbl, 2)
tbl.Delete(p("10.0.0.0/8"))
checkRoutes(t, tbl, []tableTest{
{"10.0.0.1", -1},
{"255.255.255.255", -1},
})
checkSize(t, tbl, 2)
})
t.Run("prefix_in_leaf", func(t *testing.T) {
// Create, then delete a single leaf table.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"255.255.255.255", -1},
})
checkSize(t, tbl, 3)
tbl.Delete(p("192.168.0.1/32"))
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", -1},
{"255.255.255.255", -1},
})
checkSize(t, tbl, 2)
})
t.Run("intermediate_no_routes", func(t *testing.T) {
// Create an intermediate with 2 children, then delete one leaf.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
tbl.Insert(p("192.180.0.1/32"), 2)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.180.0.1", 2},
{"192.40.0.1", -1},
})
checkSize(t, tbl, 5) // 2 roots, 1 intermediate, 2 leaves
tbl.Delete(p("192.180.0.1/32"))
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.180.0.1", -1},
{"192.40.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
})
t.Run("intermediate_with_route", func(t *testing.T) {
// Same, but the intermediate carries a route as well.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
tbl.Insert(p("192.180.0.1/32"), 2)
tbl.Insert(p("192.0.0.0/10"), 3)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.180.0.1", 2},
{"192.40.0.1", 3},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 5) // 2 roots, 1 intermediate, 2 leaves
tbl.Delete(p("192.180.0.1/32"))
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.180.0.1", -1},
{"192.40.0.1", 3},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 4) // 2 roots, 1 intermediate w/route, 1 leaf
})
t.Run("intermediate_many_leaves", func(t *testing.T) {
// Intermediate with 3 leaves, then delete one leaf.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
tbl.Insert(p("192.180.0.1/32"), 2)
tbl.Insert(p("192.200.0.1/32"), 3)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.180.0.1", 2},
{"192.200.0.1", 3},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 6) // 2 roots, 1 intermediate, 3 leaves
tbl.Delete(p("192.180.0.1/32"))
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.180.0.1", -1},
{"192.200.0.1", 3},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 5) // 2 roots, 1 intermediate, 2 leaves
})
t.Run("nosuchprefix_missing_child", func(t *testing.T) {
// Delete non-existent prefix, missing strideTable path.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
tbl.Delete(p("200.0.0.0/32")) // lookup miss in root
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
})
t.Run("nosuchprefix_wrong_turn", func(t *testing.T) {
// Delete non-existent prefix, strideTable path exists but
// with a wrong turn.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
tbl.Delete(p("192.40.0.0/32")) // finds wrong child
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
})
t.Run("nosuchprefix_not_in_leaf", func(t *testing.T) {
// Delete non-existent prefix, strideTable path exists but
// leaf doesn't contain route.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
tbl.Delete(p("192.168.0.5/32")) // right leaf, no route
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
})
t.Run("intermediate_with_deleted_route", func(t *testing.T) {
// Intermediate table loses its last route and becomes
// compactable.
tbl := &Table[int]{}
checkSize(t, tbl, 2)
tbl.Insert(p("192.168.0.1/32"), 1)
tbl.Insert(p("192.168.0.0/22"), 2)
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", 2},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 4) // 2 roots, 1 intermediate w/route, 1 leaf
tbl.Delete(p("192.168.0.0/22"))
checkRoutes(t, tbl, []tableTest{
{"192.168.0.1", 1},
{"192.168.0.2", -1},
{"192.255.0.1", -1},
})
checkSize(t, tbl, 3) // 2 roots, 1 leaf
})
t.Run("default_route", func(t *testing.T) {
// Default routes have a special case in the code.
tbl := &Table[int]{}
tbl.Insert(p("0.0.0.0/0"), 1)
tbl.Delete(p("0.0.0.0/0"))
checkRoutes(t, tbl, []tableTest{
{"1.2.3.4", -1},
})
checkSize(t, tbl, 2) // 2 roots
})
}
func TestInsertCompare(t *testing.T) {
// Create large route tables repeatedly, and compare Table's
// behavior to a naive and slow but correct implementation.
t.Parallel()
pfxs := randomPrefixes(10_000)
slow := slowPrefixTable[int]{pfxs}
fast := Table[int]{}
for _, pfx := range pfxs {
fast.Insert(pfx.pfx, pfx.val)
}
if debugInsert {
t.Logf(fast.debugSummary())
}
seenVals4 := map[int]bool{}
seenVals6 := map[int]bool{}
for i := 0; i < 10_000; i++ {
a := randomAddr()
slowVal, slowOK := slow.get(a)
fastVal, fastOK := fast.Get(a)
if !getsEqual(slowVal, slowOK, fastVal, fastOK) {
t.Fatalf("get(%q) = (%v, %v), want (%v, %v)", a, fastVal, fastOK, slowVal, slowOK)
}
if a.Is6() {
seenVals6[fastVal] = true
} else {
seenVals4[fastVal] = true
}
}
// Empirically, 10k probes into 5k v4 prefixes and 5k v6 prefixes results in
// ~1k distinct values for v4 and ~300 for v6. distinct routes. This sanity
// check that we didn't just return a single route for everything should be
// very generous indeed.
if cnt := len(seenVals4); cnt < 10 {
t.Fatalf("saw %d distinct v4 route results, statistically expected ~1000", cnt)
}
if cnt := len(seenVals6); cnt < 10 {
t.Fatalf("saw %d distinct v6 route results, statistically expected ~300", cnt)
}
}
func TestInsertShuffled(t *testing.T) {
// The order in which you insert prefixes into a route table
// should not matter, as long as you're inserting the same set of
// routes. Verify that this is true, because ART does execute
// vastly different code depending on the order of insertion, even
// if the end result is identical.
//
// If you're here because this package's tests are slow and you
// want to make them faster, please do not delete this test (or
// any test, really). It may seem excessive to test this, but
// these shuffle tests found a lot of very nasty edge cases during
// development, and you _really_ don't want to be debugging a
// faulty route table in production.
t.Parallel()
pfxs := randomPrefixes(1000)
var pfxs2 []slowPrefixEntry[int]
defer func() {
if t.Failed() {
t.Logf("pre-shuffle: %#v", pfxs)
t.Logf("post-shuffle: %#v", pfxs2)
}
}()
for i := 0; i < 10; i++ {
pfxs2 := append([]slowPrefixEntry[int](nil), pfxs...)
rand.Shuffle(len(pfxs2), func(i, j int) { pfxs2[i], pfxs2[j] = pfxs2[j], pfxs2[i] })
addrs := make([]netip.Addr, 0, 10_000)
for i := 0; i < 10_000; i++ {
addrs = append(addrs, randomAddr())
}
rt := Table[int]{}
rt2 := Table[int]{}
for _, pfx := range pfxs {
rt.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range pfxs2 {
rt2.Insert(pfx.pfx, pfx.val)
}
for _, a := range addrs {
val1, ok1 := rt.Get(a)
val2, ok2 := rt2.Get(a)
if !getsEqual(val1, ok1, val2, ok2) {
t.Fatalf("get(%q) = (%v, %v), want (%v, %v)", a, val2, ok2, val1, ok1)
}
}
}
}
func TestDeleteCompare(t *testing.T) {
// Create large route tables repeatedly, delete half of their
// prefixes, and compare Table's behavior to a naive and slow but
// correct implementation.
t.Parallel()
const (
numPrefixes = 10_000 // total prefixes to insert (test deletes 50% of them)
numPerFamily = numPrefixes / 2
deleteCut = numPerFamily / 2
numProbes = 10_000 // random addr lookups to do
)
// We have to do this little dance instead of just using allPrefixes,
// because we want pfxs and toDelete to be non-overlapping sets.
all4, all6 := randomPrefixes4(numPerFamily), randomPrefixes6(numPerFamily)
pfxs := append([]slowPrefixEntry[int](nil), all4[:deleteCut]...)
pfxs = append(pfxs, all6[:deleteCut]...)
toDelete := append([]slowPrefixEntry[int](nil), all4[deleteCut:]...)
toDelete = append(toDelete, all6[deleteCut:]...)
defer func() {
if t.Failed() {
for _, pfx := range pfxs {
fmt.Printf("%q, ", pfx.pfx)
}
fmt.Println("")
for _, pfx := range toDelete {
fmt.Printf("%q, ", pfx.pfx)
}
fmt.Println("")
}
}()
slow := slowPrefixTable[int]{pfxs}
fast := Table[int]{}
for _, pfx := range pfxs {
fast.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range toDelete {
fast.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range toDelete {
fast.Delete(pfx.pfx)
}
seenVals4 := map[int]bool{}
seenVals6 := map[int]bool{}
for i := 0; i < numProbes; i++ {
a := randomAddr()
slowVal, slowOK := slow.get(a)
fastVal, fastOK := fast.Get(a)
if !getsEqual(slowVal, slowOK, fastVal, fastOK) {
t.Fatalf("get(%q) = (%v, %v), want (%v, %v)", a, fastVal, fastOK, slowVal, slowOK)
}
if a.Is6() {
seenVals6[fastVal] = true
} else {
seenVals4[fastVal] = true
}
}
// Empirically, 10k probes into 5k v4 prefixes and 5k v6 prefixes results in
// ~1k distinct values for v4 and ~300 for v6. distinct routes. This sanity
// check that we didn't just return a single route for everything should be
// very generous indeed.
if cnt := len(seenVals4); cnt < 10 {
t.Fatalf("saw %d distinct v4 route results, statistically expected ~1000", cnt)
}
if cnt := len(seenVals6); cnt < 10 {
t.Fatalf("saw %d distinct v6 route results, statistically expected ~300", cnt)
}
}
func TestDeleteShuffled(t *testing.T) {
// The order in which you delete prefixes from a route table
// should not matter, as long as you're deleting the same set of
// routes. Verify that this is true, because ART does execute
// vastly different code depending on the order of deletions, even
// if the end result is identical.
//
// If you're here because this package's tests are slow and you
// want to make them faster, please do not delete this test (or
// any test, really). It may seem excessive to test this, but
// these shuffle tests found a lot of very nasty edge cases during
// development, and you _really_ don't want to be debugging a
// faulty route table in production.
t.Parallel()
const (
numPrefixes = 10_000 // prefixes to insert (test deletes 50% of them)
numPerFamily = numPrefixes / 2
deleteCut = numPerFamily / 2
numProbes = 10_000 // random addr lookups to do
)
// We have to do this little dance instead of just using allPrefixes,
// because we want pfxs and toDelete to be non-overlapping sets.
all4, all6 := randomPrefixes4(numPerFamily), randomPrefixes6(numPerFamily)
pfxs := append([]slowPrefixEntry[int](nil), all4[:deleteCut]...)
pfxs = append(pfxs, all6[:deleteCut]...)
toDelete := append([]slowPrefixEntry[int](nil), all4[deleteCut:]...)
toDelete = append(toDelete, all6[deleteCut:]...)
rt := Table[int]{}
for _, pfx := range pfxs {
rt.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range toDelete {
rt.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range toDelete {
rt.Delete(pfx.pfx)
}
for i := 0; i < 10; i++ {
pfxs2 := append([]slowPrefixEntry[int](nil), pfxs...)
toDelete2 := append([]slowPrefixEntry[int](nil), toDelete...)
rand.Shuffle(len(toDelete2), func(i, j int) { toDelete2[i], toDelete2[j] = toDelete2[j], toDelete2[i] })
rt2 := Table[int]{}
for _, pfx := range pfxs2 {
rt2.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range toDelete2 {
rt2.Insert(pfx.pfx, pfx.val)
}
for _, pfx := range toDelete2 {
rt2.Delete(pfx.pfx)
}
// Diffing a deep tree of tables gives cmp.Diff a nervous breakdown, so
// test for equivalence statistically with random probes instead.
for i := 0; i < numProbes; i++ {
a := randomAddr()
val1, ok1 := rt.Get(a)
val2, ok2 := rt2.Get(a)
if !getsEqual(val1, ok1, val2, ok2) {
t.Errorf("get(%q) = (%v, %v), want (%v, %v)", a, val2, ok2, val1, ok1)
}
}
}
}
func TestDeleteIsReverseOfInsert(t *testing.T) {
// Insert N prefixes, then delete those same prefixes in reverse
// order. Each deletion should exactly undo the internal structure
// changes that each insert did.
const N = 100
var tab Table[int]
prefixes := randomPrefixes(N)
defer func() {
if t.Failed() {
fmt.Printf("the prefixes that fail the test: %v\n", prefixes)
}
}()
want := make([]string, 0, len(prefixes))
for _, p := range prefixes {
want = append(want, tab.debugSummary())
tab.Insert(p.pfx, p.val)
}
for i := len(prefixes) - 1; i >= 0; i-- {
tab.Delete(prefixes[i].pfx)
if got := tab.debugSummary(); got != want[i] {
t.Fatalf("after delete %d, mismatch:\n\n got: %s\n\nwant: %s", i, got, want[i])
}
}
}
type tableTest struct {
// addr is an IP address string to look up in a route table.
addr string
// want is the expected >=0 value associated with the route, or -1
// if we expect a lookup miss.
want int
}
// checkRoutes verifies that the route lookups in tt return the
// expected results on tbl.
func checkRoutes(t *testing.T, tbl *Table[int], tt []tableTest) {
t.Helper()
for _, tc := range tt {
v, ok := tbl.Get(netip.MustParseAddr(tc.addr))
if !ok && tc.want != -1 {
t.Errorf("lookup %q got (%v, %v), want (_, false)", tc.addr, v, ok)
}
if ok && v != tc.want {
t.Errorf("lookup %q got (%v, %v), want (%v, true)", tc.addr, v, ok, tc.want)
}
}
}
// 100k routes for IPv6, at the current size of strideTable and strideEntry, is
// in the ballpark of 4GiB if you assume worst-case prefix distribution. Future
// optimizations will knock down the memory consumption by over an order of
// magnitude, so for now just skip the 100k benchmarks to stay well away of
// OOMs.
//
// TODO(go/bug/7781): reenable larger table tests once memory utilization is
// optimized.
var benchRouteCount = []int{10, 100, 1000, 10_000} //, 100_000}
// forFamilyAndCount runs the benchmark fn with different sets of
// routes.
//
// fn is called once for each combination of {addr_family, num_routes},
// where addr_family is ipv4 or ipv6, num_routes is the values in
// benchRouteCount.
func forFamilyAndCount(b *testing.B, fn func(b *testing.B, routes []slowPrefixEntry[int])) {
for _, fam := range []string{"ipv4", "ipv6"} {
rng := randomPrefixes4
if fam == "ipv6" {
rng = randomPrefixes6
}
b.Run(fam, func(b *testing.B) {
for _, nroutes := range benchRouteCount {
routes := rng(nroutes)
b.Run(fmt.Sprint(nroutes), func(b *testing.B) {
fn(b, routes)
})
}
})
}
}
func BenchmarkTableInsertion(b *testing.B) {
forFamilyAndCount(b, func(b *testing.B, routes []slowPrefixEntry[int]) {
b.StopTimer()
b.ResetTimer()
var startMem, endMem runtime.MemStats
runtime.ReadMemStats(&startMem)
b.StartTimer()
for i := 0; i < b.N; i++ {
var rt Table[int]
for _, route := range routes {
rt.Insert(route.pfx, route.val)
}
}
b.StopTimer()
runtime.ReadMemStats(&endMem)
inserts := float64(b.N) * float64(len(routes))
allocs := float64(endMem.Mallocs - startMem.Mallocs)
bytes := float64(endMem.TotalAlloc - startMem.TotalAlloc)
elapsed := float64(b.Elapsed().Nanoseconds())
elapsedSec := b.Elapsed().Seconds()
b.ReportMetric(elapsed/inserts, "ns/op")
b.ReportMetric(inserts/elapsedSec, "routes/s")
b.ReportMetric(roundFloat64(allocs/inserts), "avg-allocs/op")
b.ReportMetric(roundFloat64(bytes/inserts), "avg-B/op")
})
}
func BenchmarkTableDelete(b *testing.B) {
forFamilyAndCount(b, func(b *testing.B, routes []slowPrefixEntry[int]) {
// Collect memstats for one round of insertions, so we can remove it
// from the total at the end and get only the deletion alloc count.
insertAllocs, insertBytes := getMemCost(func() {
var rt Table[int]
for _, route := range routes {
rt.Insert(route.pfx, route.val)
}
})
insertAllocs *= float64(b.N)
insertBytes *= float64(b.N)
var t runningTimer
allocs, bytes := getMemCost(func() {
for i := 0; i < b.N; i++ {
var rt Table[int]
for _, route := range routes {
rt.Insert(route.pfx, route.val)
}
t.Start()
for _, route := range routes {
rt.Delete(route.pfx)
}
t.Stop()
}
})
inserts := float64(b.N) * float64(len(routes))
allocs -= insertAllocs
bytes -= insertBytes
elapsed := float64(t.Elapsed().Nanoseconds())
elapsedSec := t.Elapsed().Seconds()
b.ReportMetric(elapsed/inserts, "ns/op")
b.ReportMetric(inserts/elapsedSec, "routes/s")
b.ReportMetric(roundFloat64(allocs/inserts), "avg-allocs/op")
b.ReportMetric(roundFloat64(bytes/inserts), "avg-B/op")
})
}
var addrSink netip.Addr
func BenchmarkTableGet(b *testing.B) {
forFamilyAndCount(b, func(b *testing.B, routes []slowPrefixEntry[int]) {
genAddr := randomAddr4
if routes[0].pfx.Addr().Is6() {
genAddr = randomAddr6
}
var rt Table[int]
for _, route := range routes {
rt.Insert(route.pfx, route.val)
}
addrAllocs, addrBytes := getMemCost(func() {
// Have to run genAddr more than once, otherwise the reported
// cost is 16 bytes - presumably due to some amortized costs in
// the memory allocator? Either way, empirically 100 iterations
// reliably reports the correct cost.
for i := 0; i < 100; i++ {
_ = genAddr()
}
})
addrAllocs /= 100
addrBytes /= 100
var t runningTimer
allocs, bytes := getMemCost(func() {
for i := 0; i < b.N; i++ {
addr := genAddr()
t.Start()
writeSink, _ = rt.Get(addr)
t.Stop()
}
})
b.ReportAllocs() // Enables the output, but we report manually below
allocs -= (addrAllocs * float64(b.N))
bytes -= (addrBytes * float64(b.N))
lookups := float64(b.N)
elapsed := float64(t.Elapsed().Nanoseconds())
elapsedSec := float64(t.Elapsed().Seconds())
b.ReportMetric(elapsed/lookups, "ns/op")
b.ReportMetric(lookups/elapsedSec, "addrs/s")
b.ReportMetric(allocs/lookups, "allocs/op")
b.ReportMetric(bytes/lookups, "B/op")
})
}
// getMemCost runs fn 100 times and returns the number of allocations and bytes
// allocated by each call to fn.
//
// Note that if your fn allocates very little memory (less than ~16 bytes), you
// should make fn run its workload ~100 times and divide the results of
// getMemCost yourself. Otherwise, the byte count you get will be rounded up due
// to the memory allocator's bucketing granularity.
func getMemCost(fn func()) (allocs, bytes float64) {
var start, end runtime.MemStats
runtime.ReadMemStats(&start)
fn()
runtime.ReadMemStats(&end)
return float64(end.Mallocs - start.Mallocs), float64(end.TotalAlloc - start.TotalAlloc)
}
// runningTimer is a timer that keeps track of the cumulative time it's spent
// running since creation. A newly created runningTimer is stopped.
//
// This timer exists because some of our benchmarks have to interleave costly
// ancillary logic in each benchmark iteration, rather than being able to
// front-load all the work before a single b.ResetTimer().
//
// As it turns out, b.StartTimer() and b.StopTimer() are expensive function
// calls, because they do costly memory allocation accounting on every call.
// Starting and stopping the benchmark timer in every b.N loop iteration slows
// the benchmarks down by orders of magnitude.
//
// So, rather than rely on testing.B's timing facility, we use this very
// lightweight timer combined with getMemCost to do our own accounting more
// efficiently.
type runningTimer struct {
cumulative time.Duration
start time.Time
}
func (t *runningTimer) Start() {
t.Stop()
t.start = time.Now()
}
func (t *runningTimer) Stop() {
if t.start.IsZero() {
return
}
t.cumulative += time.Since(t.start)
t.start = time.Time{}
}
func (t *runningTimer) Elapsed() time.Duration {
return t.cumulative
}
func checkSize(t *testing.T, tbl *Table[int], want int) {
t.Helper()
if got := tbl.numStrides(); got != want {
t.Errorf("wrong table size, got %d strides want %d", got, want)
}
}
func (t *Table[T]) numStrides() int {
seen := map[*strideTable[T]]bool{}
return t.numStridesRec(seen, &t.v4) + t.numStridesRec(seen, &t.v6)
}
func (t *Table[T]) numStridesRec(seen map[*strideTable[T]]bool, st *strideTable[T]) int {
ret := 1
if st.childRefs == 0 {
return ret
}
for _, c := range st.children {
if c == nil || seen[c] {
continue
}
seen[c] = true
ret += t.numStridesRec(seen, c)
}
return ret
}
// slowPrefixTable is a routing table implemented as a set of prefixes that are
// explicitly scanned in full for every route lookup. It is very slow, but also
// reasonably easy to verify by inspection, and so a good correctness reference
// for Table.
type slowPrefixTable[T any] struct {
prefixes []slowPrefixEntry[T]
}
type slowPrefixEntry[T any] struct {
pfx netip.Prefix
val T
}
func (t *slowPrefixTable[T]) delete(pfx netip.Prefix) {
pfx = pfx.Masked()
ret := make([]slowPrefixEntry[T], 0, len(t.prefixes))
for _, ent := range t.prefixes {
if ent.pfx == pfx {
continue
}
ret = append(ret, ent)
}
t.prefixes = ret
}
func (t *slowPrefixTable[T]) insert(pfx netip.Prefix, val T) {
pfx = pfx.Masked()
for i, ent := range t.prefixes {
if ent.pfx == pfx {
t.prefixes[i].val = val
return
}
}
t.prefixes = append(t.prefixes, slowPrefixEntry[T]{pfx, val})
}
func (t *slowPrefixTable[T]) get(addr netip.Addr) (ret T, ok bool) {
bestLen := -1
for _, pfx := range t.prefixes {
if pfx.pfx.Contains(addr) && pfx.pfx.Bits() > bestLen {
ret = pfx.val
bestLen = pfx.pfx.Bits()
}
}
return ret, bestLen != -1
}
// randomPrefixes returns n randomly generated prefixes and associated values,
// distributed equally between IPv4 and IPv6.
func randomPrefixes(n int) []slowPrefixEntry[int] {
pfxs := randomPrefixes4(n / 2)
pfxs = append(pfxs, randomPrefixes6(n-len(pfxs))...)
return pfxs
}
// randomPrefixes4 returns n randomly generated IPv4 prefixes and associated values.
func randomPrefixes4(n int) []slowPrefixEntry[int] {
pfxs := map[netip.Prefix]bool{}
for len(pfxs) < n {
len := rand.Intn(33)
pfx, err := randomAddr4().Prefix(len)
if err != nil {
panic(err)
}
pfxs[pfx] = true
}
ret := make([]slowPrefixEntry[int], 0, len(pfxs))
for pfx := range pfxs {
ret = append(ret, slowPrefixEntry[int]{pfx, rand.Int()})
}
return ret
}
// randomPrefixes6 returns n randomly generated IPv4 prefixes and associated values.
func randomPrefixes6(n int) []slowPrefixEntry[int] {
pfxs := map[netip.Prefix]bool{}
for len(pfxs) < n {
len := rand.Intn(129)
pfx, err := randomAddr6().Prefix(len)
if err != nil {
panic(err)
}
pfxs[pfx] = true
}
ret := make([]slowPrefixEntry[int], 0, len(pfxs))
for pfx := range pfxs {
ret = append(ret, slowPrefixEntry[int]{pfx, rand.Int()})
}
return ret
}
// randomAddr returns a randomly generated IP address.
func randomAddr() netip.Addr {
if rand.Intn(2) == 1 {
return randomAddr6()
} else {
return randomAddr4()
}
}
// randomAddr4 returns a randomly generated IPv4 address.
func randomAddr4() netip.Addr {
var b [4]byte
if _, err := crand.Read(b[:]); err != nil {
panic(err)
}
return netip.AddrFrom4(b)
}
// randomAddr6 returns a randomly generated IPv6 address.
func randomAddr6() netip.Addr {
var b [16]byte
if _, err := crand.Read(b[:]); err != nil {
panic(err)
}
return netip.AddrFrom16(b)
}
// roundFloat64 rounds f to 2 decimal places, for display.
//
// It round-trips through a float->string->float conversion, so should not be
// used in a performance critical setting.
func roundFloat64(f float64) float64 {
s := fmt.Sprintf("%.2f", f)
ret, err := strconv.ParseFloat(s, 64)
if err != nil {
panic(err)
}
return ret
}
func minimize(pfxs []slowPrefixEntry[int], f func(skip map[netip.Prefix]bool) error) (map[netip.Prefix]bool, error) {
if f(nil) == nil {
return nil, nil
}
remove := map[netip.Prefix]bool{}
for lastLen := -1; len(remove) != lastLen; lastLen = len(remove) {
fmt.Println("len is ", len(remove))
for i, pfx := range pfxs {
if remove[pfx.pfx] {
continue
}
remove[pfx.pfx] = true
fmt.Printf("%d %d: trying without %s\n", i, len(remove), pfx.pfx)
if f(remove) == nil {
delete(remove, pfx.pfx)
}
}
}
return remove, f(remove)
}
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