mirror of
https://github.com/Control-D-Inc/ctrld.git
synced 2026-07-16 13:17:19 +02:00
Cuong Manh Le
ff14fc8ac9
When IPv6 is available locally but the selected IPv6 DoH endpoint is unroutable (e.g. dialing [2606:1a40::22]:443 returns "no route to host" while IPv4 stays usable), ctrld re-bootstrapped and re-dialed the endpoint every ~2s. A weekend soak produced ~46.7k "no route to host" lines, with the dial/health-check loop dominating the log during bad windows. Add bounded backoff/suppression for network-unreachable endpoints at two levels: - ParallelDialer (internal/net): track dial addresses that fail with ENETUNREACH/EHOSTUNREACH and skip them for an exponentially growing, bounded window (5s -> 60s). A successful dial clears the entry immediately, so recovery is preserved when the route returns. When every candidate is suppressed the dial fails fast and quietly instead of hammering known-unroutable addresses. - Upstream recovery loop (cmd/cli): demote unreachable check failures to debug and back off the retry cadence (2s -> 60s) for an unreachable streak; any other failure resets to the base cadence. The new IsUnreachable classifier lives in internal/net and is reused by cmd/cli's errNetworkError, so the unreachable-errno matching has a single definition. Note the explicit winsock constants (10051/10065) are required on Windows: syscall.ENETUNREACH/EHOSTUNREACH are Go's portable "invented" values and never equal the raw WSA codes a failing connect surfaces. Suppression and backoff are always bounded, so IPv6 is never disabled until restart and recovers on its own once the route is back. Split-stack selection and the #549 macOS intercept recovery work are untouched. Adds unit tests for the classifier, the dialer's suppression tracker, and the recovery backoff schedule.
97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
package net
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import (
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"context"
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"net"
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"syscall"
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"testing"
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"time"
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)
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func TestIsUnreachable(t *testing.T) {
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tests := []struct {
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name string
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err error
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want bool
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}{
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{"nil", nil, false},
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{"enetunreach", &net.OpError{Op: "dial", Net: "tcp", Err: syscall.ENETUNREACH}, true},
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{"ehostunreach", &net.OpError{Op: "dial", Net: "tcp", Err: syscall.EHOSTUNREACH}, true},
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{"windows enetunreach", &net.OpError{Op: "dial", Net: "tcp", Err: windowsENETUNREACH}, true},
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{"windows ehostunreach", &net.OpError{Op: "dial", Net: "tcp", Err: windowsEHOSTUNREACH}, true},
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{"connection refused", &net.OpError{Op: "dial", Net: "tcp", Err: syscall.ECONNREFUSED}, false},
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{"not an opError", syscall.ENETUNREACH, false},
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}
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for _, tc := range tests {
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tc := tc
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t.Run(tc.name, func(t *testing.T) {
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if got := IsUnreachable(tc.err); got != tc.want {
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t.Errorf("IsUnreachable(%v) = %v, want %v", tc.err, got, tc.want)
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}
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})
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}
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}
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func TestUnreachableTracker(t *testing.T) {
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tr := &unreachableTracker{entries: make(map[string]unreachableEntry)}
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const addr = "[2606:1a40::22]:443"
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now := time.Unix(0, 0)
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// Not suppressed before any failure.
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if tr.suppressed(addr, now) {
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t.Fatal("addr suppressed before any failure")
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}
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// First failure suppresses for the base window.
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tr.markUnreachable(addr, now)
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if !tr.suppressed(addr, now.Add(unreachableBackoffBase-time.Millisecond)) {
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t.Fatal("addr not suppressed within base backoff window")
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}
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if tr.suppressed(addr, now.Add(unreachableBackoffBase)) {
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t.Fatal("addr still suppressed at end of base backoff window")
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}
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// Backoff grows exponentially and is capped at the max.
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tr.markUnreachable(addr, now)
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if got := tr.entries[addr].backoff; got != 2*unreachableBackoffBase {
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t.Fatalf("backoff after second failure = %v, want %v", got, 2*unreachableBackoffBase)
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}
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for i := 0; i < 10; i++ {
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tr.markUnreachable(addr, now)
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}
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if got := tr.entries[addr].backoff; got != unreachableBackoffMax {
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t.Fatalf("backoff not capped: got %v, want %v", got, unreachableBackoffMax)
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}
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// A successful dial clears suppression entirely.
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tr.markReachable(addr)
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if tr.suppressed(addr, now) {
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t.Fatal("addr still suppressed after markReachable")
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}
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if _, ok := tr.entries[addr]; ok {
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t.Fatal("entry not removed after markReachable")
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}
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}
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func TestProbeStackTimeout(t *testing.T) {
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done := make(chan struct{})
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started := make(chan struct{})
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go func() {
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defer close(done)
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close(started)
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hasV6, port := supportIPv6(context.Background())
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if hasV6 {
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t.Logf("connect to port %s using ipv6: %v", port, hasV6)
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} else {
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t.Log("ipv6 is not available")
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}
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}()
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<-started
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select {
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case <-time.After(probeStackTimeout + time.Second):
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t.Error("probeStack timeout is not enforce")
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case <-done:
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}
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}
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