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all: avoid repeated default interface lookups

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On some platforms (notably macOS and iOS) we look up the default
interface to bind outgoing connections to. This is both duplicated
work and results in logspam when the default interface is not available
(i.e. when a phone has no connectivity, we log an error and thus cause
more things that we will try to upload and fail).

Fixed by passing around a netmon.Monitor to more places, so that we can
use its cached interface state.

Fixes #7850
Updates #7621

Signed-off-by: Mihai Parparita <mihai@tailscale.com>
This commit is contained in:
Mihai Parparita
2023-04-17 16:01:41 -07:00
committed by Mihai Parparita
parent 7f17e04a5a
commit 7330aa593e
50 changed files with 242 additions and 126 deletions
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35
logpolicy/logpolicy.go
View File

@@ -37,6 +37,7 @@ import (
"tailscale.com/net/dnscache"
"tailscale.com/net/dnsfallback"
"tailscale.com/net/netknob"
"tailscale.com/net/netmon"
"tailscale.com/net/netns"
"tailscale.com/net/tlsdial"
"tailscale.com/net/tshttpproxy"
@@ -450,14 +451,15 @@ func tryFixLogStateLocation(dir, cmdname string) {
// New returns a new log policy (a logger and its instance ID) for a
// given collection name.
func New(collection string) *Policy {
return NewWithConfigPath(collection, "", "")
// The netMon parameter is optional; if non-nil it's used to do faster interface lookups.
func New(collection string, netMon *netmon.Monitor) *Policy {
return NewWithConfigPath(collection, "", "", netMon)
}
// NewWithConfigPath is identical to New,
// but uses the specified directory and command name.
// If either is empty, it derives them automatically.
func NewWithConfigPath(collection, dir, cmdName string) *Policy {
func NewWithConfigPath(collection, dir, cmdName string, netMon *netmon.Monitor) *Policy {
var lflags int
if term.IsTerminal(2) || runtime.GOOS == "windows" {
lflags = 0
@@ -554,7 +556,7 @@ func NewWithConfigPath(collection, dir, cmdName string) *Policy {
}
return w
},
HTTPC: &http.Client{Transport: NewLogtailTransport(logtail.DefaultHost)},
HTTPC: &http.Client{Transport: NewLogtailTransport(logtail.DefaultHost, netMon)},
}
if collection == logtail.CollectionNode {
conf.MetricsDelta = clientmetric.EncodeLogTailMetricsDelta
@@ -569,7 +571,7 @@ func NewWithConfigPath(collection, dir, cmdName string) *Policy {
log.Println("You have enabled a non-default log target. Doing without being told to by Tailscale staff or your network administrator will make getting support difficult.")
conf.BaseURL = val
u, _ := url.Parse(val)
conf.HTTPC = &http.Client{Transport: NewLogtailTransport(u.Host)}
conf.HTTPC = &http.Client{Transport: NewLogtailTransport(u.Host, netMon)}
}
filchOptions := filch.Options{
@@ -670,13 +672,22 @@ func (p *Policy) Shutdown(ctx context.Context) error {
return nil
}
// DialContext is a net.Dialer.DialContext specialized for use by logtail.
// MakeDialFunc creates a net.Dialer.DialContext function specialized for use
// by logtail.
// It does the following:
// - If DNS lookup fails, consults the bootstrap DNS list of Tailscale hostnames.
// - If TLS connection fails, try again using LetsEncrypt's built-in root certificate,
// for the benefit of older OS platforms which might not include it.
func DialContext(ctx context.Context, netw, addr string) (net.Conn, error) {
nd := netns.FromDialer(log.Printf, &net.Dialer{
//
// The netMon parameter is optional; if non-nil it's used to do faster interface lookups.
func MakeDialFunc(netMon *netmon.Monitor) func(ctx context.Context, netw, addr string) (net.Conn, error) {
return func(ctx context.Context, netw, addr string) (net.Conn, error) {
return dialContext(ctx, netw, addr, netMon)
}
}
func dialContext(ctx context.Context, netw, addr string, netMon *netmon.Monitor) (net.Conn, error) {
nd := netns.FromDialer(log.Printf, netMon, &net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: netknob.PlatformTCPKeepAlive(),
})
@@ -711,7 +722,8 @@ func DialContext(ctx context.Context, netw, addr string) (net.Conn, error) {
dnsCache := &dnscache.Resolver{
Forward: dnscache.Get().Forward, // use default cache's forwarder
UseLastGood: true,
LookupIPFallback: dnsfallback.Lookup(log.Printf),
LookupIPFallback: dnsfallback.MakeLookupFunc(log.Printf, netMon),
NetMon: netMon,
}
dialer := dnscache.Dialer(nd.DialContext, dnsCache)
c, err = dialer(ctx, netw, addr)
@@ -723,7 +735,8 @@ func DialContext(ctx context.Context, netw, addr string) (net.Conn, error) {
// NewLogtailTransport returns an HTTP Transport particularly suited to uploading
// logs to the given host name. See DialContext for details on how it works.
func NewLogtailTransport(host string) http.RoundTripper {
// The netMon parameter is optional; if non-nil it's used to do faster interface lookups.
func NewLogtailTransport(host string, netMon *netmon.Monitor) http.RoundTripper {
if inTest() {
return noopPretendSuccessTransport{}
}
@@ -739,7 +752,7 @@ func NewLogtailTransport(host string) http.RoundTripper {
tr.DisableCompression = true
// Log whenever we dial:
tr.DialContext = DialContext
tr.DialContext = MakeDialFunc(netMon)
// We're contacting exactly 1 hostname, so the default's 100
// max idle conns is very high for our needs. Even 2 is