Simon LawandSimon Law
ca91eafce5
Add a new `--force-probe` flag to `tailscale exit-node suggest` that waits for a routecheck.Refresh to finish before suggesting an exit node. This flag is currently hidden from the help text, but this flag is a hint to the user that exit-node suggestions are based on routecheck reachability reports. Updates #17366 Updates tailscale/corp#33033 Signed-off-by: Simon Law <sfllaw@tailscale.com>
85 lines
2.4 KiB
Go
85 lines
2.4 KiB
Go
// Copyright (c) Tailscale Inc & contributors
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// SPDX-License-Identifier: BSD-3-Clause
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package routecheck
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import (
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"context"
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"errors"
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"net/http"
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"time"
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jsonv2 "github.com/go-json-experiment/json"
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jsonv1 "github.com/go-json-experiment/json/v1"
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"tailscale.com/ipn/ipnlocal"
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"tailscale.com/ipn/localapi"
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"tailscale.com/net/routecheck"
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"tailscale.com/util/def"
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"tailscale.com/util/httpm"
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)
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func init() {
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localapi.Register("routecheck", serveRouteCheck)
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localapi.HookRouteCheckRefresh.Set(routeCheckRefresh)
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}
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// ServeRouteCheck handles the API endpoint that serves the routecheck Report.
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// If the probe form field is true, then this handler will refresh the Report
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// before serving it.
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// If the timeout form field is a valid duration, the probe will consider a node
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// to be unreachable if it doesn’t respond before the timeout expires.
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func serveRouteCheck(h *localapi.Handler, w http.ResponseWriter, r *http.Request) {
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rc := ClientFor(h.LocalBackend())
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if rc == nil {
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http.Error(w, "routecheck is not enabled", http.StatusServiceUnavailable)
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return
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}
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if r.Method != httpm.POST {
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http.Error(w, "want POST", http.StatusMethodNotAllowed)
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return
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}
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report := rc.Report()
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if def.Bool(r.FormValue("probe"), false) {
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timeout := def.Duration(r.FormValue("timeout"), routecheck.DefaultTimeout)
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timeout = clampRouteCheckTimeout(timeout)
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rp, err := rc.Refresh(r.Context(), timeout)
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if err != nil {
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localapi.WriteErrorJSON(w, err)
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return
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}
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report = rp
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}
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w.Header().Set("Content-Type", "application/json")
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if report == nil {
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w.WriteHeader(http.StatusNoContent)
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return
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}
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// TODO(sfllaw): Since ipn/localapi is still using encoding/json
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// with its default options, marshal with DefaultOptionsV1.
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jsonv2.MarshalWrite(w, report, jsonv1.DefaultOptionsV1())
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}
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func clampRouteCheckTimeout(timeout time.Duration) time.Duration {
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if timeout < 0 {
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timeout = routecheck.DefaultTimeout
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}
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return min(max(0, timeout), 60*time.Second) // clamp to [0s, 60s]
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}
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// routeCheckRefresh is a localapi hook for refreshing the [routecheck.Client.Report].
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// If the timeout is 0, all probes will timeout immediately.
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// If the timeout is negative, then all probes will use the [DefaultTimeout].
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func routeCheckRefresh(b *ipnlocal.LocalBackend, ctx context.Context, timeout time.Duration) error {
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rc := ClientFor(b)
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if rc == nil {
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return errors.New("routecheck is not enabled")
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}
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_, err := rc.Refresh(ctx, clampRouteCheckTimeout(timeout))
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return err
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}
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