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lanscaping: remove dnsfallback's recursive resolver + its miekg/dns dep
-rwxr-xr-x@ 1 bradfitz staff 15876722 Jan 10 20:47 /Users/bradfitz/bin/tailscaled.min -rwxr-xr-x@ 1 bradfitz staff 17039512 Jan 10 20:47 /Users/bradfitz/bin/tailscaled.minlinux Change-Id: I5e6b54545ac61d98e5075de57c3a020eab52956e Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
parent
f86f0f793a
commit
2348da8980
@ -24,7 +24,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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L 💣 github.com/mdlayher/netlink from github.com/jsimonetti/rtnetlink+
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L 💣 github.com/mdlayher/netlink/nlenc from github.com/jsimonetti/rtnetlink+
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L 💣 github.com/mdlayher/socket from github.com/mdlayher/netlink
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github.com/miekg/dns from tailscale.com/net/dns/recursive
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💣 github.com/mitchellh/go-ps from tailscale.com/cmd/tailscale/cli+
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github.com/peterbourgon/ff/v3 from github.com/peterbourgon/ff/v3/ffcli+
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github.com/peterbourgon/ff/v3/ffcli from tailscale.com/cmd/tailscale/cli+
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@ -77,7 +76,6 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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tailscale.com/kube/kubetypes from tailscale.com/envknob
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tailscale.com/licenses from tailscale.com/client/web+
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tailscale.com/metrics from tailscale.com/derp+
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tailscale.com/net/dns/recursive from tailscale.com/net/dnsfallback
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tailscale.com/net/dnscache from tailscale.com/control/controlhttp+
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tailscale.com/net/dnsfallback from tailscale.com/control/controlhttp
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tailscale.com/net/flowtrack from tailscale.com/net/packet
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@ -184,8 +182,8 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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golang.org/x/net/http2/hpack from golang.org/x/net/http2+
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golang.org/x/net/icmp from tailscale.com/net/ping
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golang.org/x/net/idna from golang.org/x/net/http/httpguts+
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golang.org/x/net/ipv4 from github.com/miekg/dns+
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golang.org/x/net/ipv6 from github.com/miekg/dns+
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golang.org/x/net/ipv4 from golang.org/x/net/icmp+
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golang.org/x/net/ipv6 from golang.org/x/net/icmp+
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golang.org/x/net/proxy from tailscale.com/net/netns
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D golang.org/x/net/route from net+
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golang.org/x/oauth2 from golang.org/x/oauth2/clientcredentials
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@ -226,7 +224,7 @@ tailscale.com/cmd/tailscale dependencies: (generated by github.com/tailscale/dep
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crypto/sha256 from crypto/tls+
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crypto/sha512 from crypto/ecdsa+
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crypto/subtle from crypto/aes+
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crypto/tls from github.com/miekg/dns+
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crypto/tls from golang.org/x/net/http2+
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crypto/x509 from crypto/tls+
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crypto/x509/pkix from crypto/x509+
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D database/sql/driver from github.com/google/uuid
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@ -35,7 +35,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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L 💣 github.com/mdlayher/netlink/nlenc from github.com/jsimonetti/rtnetlink+
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L github.com/mdlayher/sdnotify from tailscale.com/util/systemd
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L 💣 github.com/mdlayher/socket from github.com/mdlayher/netlink+
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github.com/miekg/dns from tailscale.com/net/dns/recursive
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💣 github.com/mitchellh/go-ps from tailscale.com/safesocket
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L 💣 github.com/safchain/ethtool from tailscale.com/doctor/ethtool+
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github.com/tailscale/golang-x-crypto/acme from tailscale.com/ipn/ipnlocal
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@ -115,7 +114,6 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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tailscale.com/net/connstats from tailscale.com/net/tstun+
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tailscale.com/net/dns from tailscale.com/cmd/tailscaled+
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tailscale.com/net/dns/publicdns from tailscale.com/net/dns+
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tailscale.com/net/dns/recursive from tailscale.com/net/dnsfallback
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tailscale.com/net/dns/resolvconffile from tailscale.com/net/dns+
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tailscale.com/net/dns/resolver from tailscale.com/net/dns
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tailscale.com/net/dnscache from tailscale.com/control/controlclient+
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@ -269,8 +267,8 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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golang.org/x/net/http2/hpack from golang.org/x/net/http2+
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golang.org/x/net/icmp from tailscale.com/net/ping
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golang.org/x/net/idna from golang.org/x/net/http/httpguts+
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golang.org/x/net/ipv4 from github.com/miekg/dns+
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golang.org/x/net/ipv6 from github.com/miekg/dns+
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golang.org/x/net/ipv4 from github.com/tailscale/wireguard-go/conn+
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golang.org/x/net/ipv6 from github.com/tailscale/wireguard-go/conn+
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golang.org/x/net/proxy from tailscale.com/net/netns
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D golang.org/x/net/route from net+
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golang.org/x/sync/errgroup from github.com/mdlayher/socket+
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@ -308,7 +306,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
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crypto/sha256 from crypto/tls+
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crypto/sha512 from crypto/ecdsa+
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crypto/subtle from crypto/aes+
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crypto/tls from github.com/miekg/dns+
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crypto/tls from github.com/tailscale/golang-x-crypto/acme+
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crypto/x509 from crypto/tls+
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crypto/x509/pkix from crypto/x509+
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embed from crypto/internal/nistec+
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@ -29,7 +29,6 @@ import (
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"tailscale.com/atomicfile"
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"tailscale.com/envknob"
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"tailscale.com/health"
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"tailscale.com/net/dns/recursive"
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"tailscale.com/net/netmon"
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"tailscale.com/net/netns"
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"tailscale.com/net/tlsdial"
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@ -95,10 +94,8 @@ func (fr *fallbackResolver) Lookup(ctx context.Context, host string) ([]netip.Ad
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done = make(chan struct{})
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go func() {
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defer close(done)
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fr.compareWithRecursive(ctx, addrsCh, host)
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}()
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} else {
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go fr.compareWithRecursive(ctx, addrsCh, host)
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}
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addrs, err := lookup(ctx, host, fr.logf, fr.healthTracker, fr.netMon)
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@ -117,98 +114,6 @@ func (fr *fallbackResolver) Lookup(ctx context.Context, host string) ([]netip.Ad
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return addrs, nil
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}
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// compareWithRecursive is responsible for comparing the DNS resolution
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// performed via the "normal" path (bootstrap DNS requests to the DERP servers)
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// with DNS resolution performed with our in-process recursive DNS resolver.
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//
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// It will select on addrsCh to read exactly one set of addrs (returned by the
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// "normal" path) and compare against the results returned by the recursive
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// resolver. If ctx is canceled, then it will abort.
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func (fr *fallbackResolver) compareWithRecursive(
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ctx context.Context,
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addrsCh <-chan []netip.Addr,
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host string,
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) {
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logf := logger.WithPrefix(fr.logf, "recursive: ")
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// Ensure that we catch panics while we're testing this
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// code path; this should never panic, but we don't
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// want to take down the process by having the panic
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// propagate to the top of the goroutine's stack and
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// then terminate.
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defer func() {
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if r := recover(); r != nil {
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logf("bootstrap DNS: recovered panic: %v", r)
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metricRecursiveErrors.Add(1)
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}
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}()
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// Don't resolve the same host multiple times
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// concurrently; if we end up in a tight loop, this can
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// take up a lot of CPU.
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var didRun bool
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result, err, _ := fr.sf.Do(host, func() (resolveResult, error) {
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didRun = true
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resolver := &recursive.Resolver{
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Dialer: netns.NewDialer(logf, fr.netMon),
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Logf: logf,
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}
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addrs, minTTL, err := resolver.Resolve(ctx, host)
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if err != nil {
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logf("error using recursive resolver: %v", err)
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metricRecursiveErrors.Add(1)
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return resolveResult{}, err
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}
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return resolveResult{addrs, minTTL}, nil
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})
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// The singleflight function handled errors; return if
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// there was one. Additionally, don't bother doing the
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// comparison if we waited on another singleflight
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// caller; the results are likely to be the same, so
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// rather than spam the logs we can just exit and let
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// the singleflight call that did execute do the
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// comparison.
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//
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// Returning here is safe because the addrsCh channel
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// is buffered, so the main function won't block even
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// if we never read from it.
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if err != nil || !didRun {
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return
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}
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addrs, minTTL := result.addrs, result.minTTL
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compareAddr := func(a, b netip.Addr) int { return a.Compare(b) }
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slices.SortFunc(addrs, compareAddr)
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// Wait for a response from the main function; try this once before we
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// check whether the context is canceled since selects are
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// nondeterministic.
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var oldAddrs []netip.Addr
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select {
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case oldAddrs = <-addrsCh:
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// All good; continue
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default:
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// Now block.
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select {
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case oldAddrs = <-addrsCh:
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case <-ctx.Done():
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return
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}
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}
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slices.SortFunc(oldAddrs, compareAddr)
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matches := slices.Equal(addrs, oldAddrs)
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logf("bootstrap DNS comparison: matches=%v oldAddrs=%v addrs=%v minTTL=%v", matches, oldAddrs, addrs, minTTL)
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if matches {
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metricRecursiveMatches.Add(1)
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} else {
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metricRecursiveMismatches.Add(1)
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}
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}
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func lookup(ctx context.Context, host string, logf logger.Logf, ht *health.Tracker, netMon *netmon.Monitor) ([]netip.Addr, error) {
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if ip, err := netip.ParseAddr(host); err == nil && ip.IsValid() {
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return []netip.Addr{ip}, nil
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