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envknob: support changing envknobs post-init

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Updates #5114

Change-Id: Ia423fc7486e1b3f3180a26308278be0086fae49b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2022-09-14 12:49:39 -07:00
committed by Brad Fitzpatrick
parent 33ee2c058e
commit 74674b110d
31 changed files with 311 additions and 167 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
net/dns/manager_windows.go
View File

@@ -32,7 +32,7 @@ const (
versionKey = `SOFTWARE\Microsoft\Windows NT\CurrentVersion`
)
var configureWSL = envknob.Bool("TS_DEBUG_CONFIGURE_WSL")
var configureWSL = envknob.RegisterBool("TS_DEBUG_CONFIGURE_WSL")
type windowsManager struct {
logf logger.Logf
@@ -359,7 +359,7 @@ func (m windowsManager) SetDNS(cfg OSConfig) error {
// On initial setup of WSL, the restart caused by --shutdown is slow,
// so we do it out-of-line.
if configureWSL {
if configureWSL() {
go func() {
if err := m.wslManager.SetDNS(cfg); err != nil {
m.logf("WSL SetDNS: %v", err) // continue

4
net/dns/resolver/forwarder.go
View File

@@ -484,13 +484,13 @@ func (f *forwarder) sendDoH(ctx context.Context, urlBase string, c *http.Client,
return res, err
}
var verboseDNSForward = envknob.Bool("TS_DEBUG_DNS_FORWARD_SEND")
var verboseDNSForward = envknob.RegisterBool("TS_DEBUG_DNS_FORWARD_SEND")
// send sends packet to dst. It is best effort.
//
// send expects the reply to have the same txid as txidOut.
func (f *forwarder) send(ctx context.Context, fq *forwardQuery, rr resolverAndDelay) (ret []byte, err error) {
if verboseDNSForward {
if verboseDNSForward() {
f.logf("forwarder.send(%q) ...", rr.name.Addr)
defer func() {
f.logf("forwarder.send(%q) = %v, %v", rr.name.Addr, len(ret), err)

26
net/dnscache/dnscache.go
View File

@@ -141,7 +141,7 @@ func (r *Resolver) ttl() time.Duration {
return 10 * time.Minute
}
var debug = envknob.Bool("TS_DEBUG_DNS_CACHE")
var debug = envknob.RegisterBool("TS_DEBUG_DNS_CACHE")
// LookupIP returns the host's primary IP address (either IPv4 or
// IPv6, but preferring IPv4) and optionally its IPv6 address, if
@@ -167,14 +167,14 @@ func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 netip.Addr
}
if ip, err := netip.ParseAddr(host); err == nil {
ip = ip.Unmap()
if debug {
if debug() {
log.Printf("dnscache: %q is an IP", host)
}
return ip, zaddr, []netip.Addr{ip}, nil
}
if ip, ip6, allIPs, ok := r.lookupIPCache(host); ok {
if debug {
if debug() {
log.Printf("dnscache: %q = %v (cached)", host, ip)
}
return ip, ip6, allIPs, nil
@@ -192,13 +192,13 @@ func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 netip.Addr
if res.Err != nil {
if r.UseLastGood {
if ip, ip6, allIPs, ok := r.lookupIPCacheExpired(host); ok {
if debug {
if debug() {
log.Printf("dnscache: %q using %v after error", host, ip)
}
return ip, ip6, allIPs, nil
}
}
if debug {
if debug() {
log.Printf("dnscache: error resolving %q: %v", host, res.Err)
}
return zaddr, zaddr, nil, res.Err
@@ -206,7 +206,7 @@ func (r *Resolver) LookupIP(ctx context.Context, host string) (ip, v6 netip.Addr
r := res.Val
return r.ip, r.ip6, r.allIPs, nil
case <-ctx.Done():
if debug {
if debug() {
log.Printf("dnscache: context done while resolving %q: %v", host, ctx.Err())
}
return zaddr, zaddr, nil, ctx.Err()
@@ -250,7 +250,7 @@ func (r *Resolver) lookupTimeoutForHost(host string) time.Duration {
func (r *Resolver) lookupIP(host string) (ip, ip6 netip.Addr, allIPs []netip.Addr, err error) {
if ip, ip6, allIPs, ok := r.lookupIPCache(host); ok {
if debug {
if debug() {
log.Printf("dnscache: %q found in cache as %v", host, ip)
}
return ip, ip6, allIPs, nil
@@ -300,13 +300,13 @@ func (r *Resolver) addIPCache(host string, ip, ip6 netip.Addr, allIPs []netip.Ad
if ip.IsPrivate() {
// Don't cache obviously wrong entries from captive portals.
// TODO: use DoH or DoT for the forwarding resolver?
if debug {
if debug() {
log.Printf("dnscache: %q resolved to private IP %v; using but not caching", host, ip)
}
return
}
if debug {
if debug() {
log.Printf("dnscache: %q resolved to IP %v; caching", host, ip)
}
@@ -382,7 +382,7 @@ func (d *dialer) DialContext(ctx context.Context, network, address string) (retC
}
i4s := v4addrs(allIPs)
if len(i4s) < 2 {
if debug {
if debug() {
log.Printf("dnscache: dialing %s, %s for %s", network, ip, address)
}
c, err := dc.dialOne(ctx, ip.Unmap())
@@ -406,7 +406,7 @@ func (d *dialer) shouldTryBootstrap(ctx context.Context, err error, dc *dialCall
// Can't try bootstrap DNS if we don't have a fallback function
if d.dnsCache.LookupIPFallback == nil {
if debug {
if debug() {
log.Printf("dnscache: not using bootstrap DNS: no fallback")
}
return false
@@ -415,7 +415,7 @@ func (d *dialer) shouldTryBootstrap(ctx context.Context, err error, dc *dialCall
// We can't retry if the context is canceled, since any further
// operations with this context will fail.
if ctxErr := ctx.Err(); ctxErr != nil {
if debug {
if debug() {
log.Printf("dnscache: not using bootstrap DNS: context error: %v", ctxErr)
}
return false
@@ -423,7 +423,7 @@ func (d *dialer) shouldTryBootstrap(ctx context.Context, err error, dc *dialCall
wasTrustworthy := dc.dnsWasTrustworthy()
if wasTrustworthy {
if debug {
if debug() {
log.Printf("dnscache: not using bootstrap DNS: DNS was trustworthy")
}
return false

6
net/dnscache/dnscache_test.go
View File

@@ -167,10 +167,8 @@ func TestInterleaveSlices(t *testing.T) {
func TestShouldTryBootstrap(t *testing.T) {
oldDebug := debug
t.Cleanup(func() {
debug = oldDebug
})
debug = true
t.Cleanup(func() { debug = oldDebug })
debug = func() bool { return true }
type step struct {
ip netip.Addr // IP we pretended to dial

4
net/netcheck/netcheck.go
View File

@@ -43,7 +43,7 @@ import (
// Debugging and experimentation tweakables.
var (
debugNetcheck = envknob.Bool("TS_DEBUG_NETCHECK")
debugNetcheck = envknob.RegisterBool("TS_DEBUG_NETCHECK")
)
// The various default timeouts for things.
@@ -210,7 +210,7 @@ func (c *Client) logf(format string, a ...any) {
}
func (c *Client) vlogf(format string, a ...any) {
if c.Verbose || debugNetcheck {
if c.Verbose || debugNetcheck() {
c.logf(format, a...)
}
}

4
net/netns/netns_linux.go
View File

@@ -63,12 +63,12 @@ func socketMarkWorks() bool {
return true
}
var forceBindToDevice = envknob.Bool("TS_FORCE_LINUX_BIND_TO_DEVICE")
var forceBindToDevice = envknob.RegisterBool("TS_FORCE_LINUX_BIND_TO_DEVICE")
// UseSocketMark reports whether SO_MARK is in use.
// If it doesn't, we have to use SO_BINDTODEVICE on our sockets instead.
func UseSocketMark() bool {
if forceBindToDevice {
if forceBindToDevice() {
return false
}
socketMarkWorksOnce.Do(func() {

10
net/tlsdial/tlsdial.go
View File

@@ -32,7 +32,7 @@ var counterFallbackOK int32 // atomic
// See https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format
var sslKeyLogFile = os.Getenv("SSLKEYLOGFILE")
var debug = envknob.Bool("TS_DEBUG_TLS_DIAL")
var debug = envknob.RegisterBool("TS_DEBUG_TLS_DIAL")
// Config returns a tls.Config for connecting to a server.
// If base is non-nil, it's cloned as the base config before
@@ -77,7 +77,7 @@ func Config(host string, base *tls.Config) *tls.Config {
opts.Intermediates.AddCert(cert)
}
_, errSys := cs.PeerCertificates[0].Verify(opts)
if debug {
if debug() {
log.Printf("tlsdial(sys %q): %v", host, errSys)
}
if errSys == nil {
@@ -88,7 +88,7 @@ func Config(host string, base *tls.Config) *tls.Config {
// or broken, fall back to trying LetsEncrypt at least.
opts.Roots = bakedInRoots()
_, err := cs.PeerCertificates[0].Verify(opts)
if debug {
if debug() {
log.Printf("tlsdial(bake %q): %v", host, err)
}
if err == nil {
@@ -142,7 +142,7 @@ func SetConfigExpectedCert(c *tls.Config, certDNSName string) {
opts.Intermediates.AddCert(cert)
}
_, errSys := certs[0].Verify(opts)
if debug {
if debug() {
log.Printf("tlsdial(sys %q/%q): %v", c.ServerName, certDNSName, errSys)
}
if errSys == nil {
@@ -150,7 +150,7 @@ func SetConfigExpectedCert(c *tls.Config, certDNSName string) {
}
opts.Roots = bakedInRoots()
_, err := certs[0].Verify(opts)
if debug {
if debug() {
log.Printf("tlsdial(bake %q/%q): %v", c.ServerName, certDNSName, err)
}
if err == nil {

12
net/tstun/tun.go
View File

@@ -20,14 +20,6 @@ import (
"tailscale.com/types/logger"
)
var tunMTU = DefaultMTU
func init() {
if mtu, ok := envknob.LookupInt("TS_DEBUG_MTU"); ok {
tunMTU = mtu
}
}
// createTAP is non-nil on Linux.
var createTAP func(tapName, bridgeName string) (tun.Device, error)
@@ -52,6 +44,10 @@ func New(logf logger.Logf, tunName string) (tun.Device, string, error) {
}
dev, err = createTAP(tapName, bridgeName)
} else {
tunMTU := DefaultMTU
if mtu, ok := envknob.LookupInt("TS_DEBUG_MTU"); ok {
tunMTU = mtu
}
dev, err = tun.CreateTUN(tunName, tunMTU)
}
if err != nil {