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101 lines
4.3 KiB
Go
101 lines
4.3 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build !ios && !js
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package magicsock
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import (
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"log"
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"net/netip"
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"strings"
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"sync"
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"tailscale.com/envknob"
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)
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// Various debugging and experimental tweakables, set by environment
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// variable.
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var (
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// debugDisco prints verbose logs of active discovery events as
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// they happen.
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debugDisco = envknob.RegisterBool("TS_DEBUG_DISCO")
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// debugPeerMap prints verbose logs of changes to the peermap.
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debugPeerMap = envknob.RegisterBool("TS_DEBUG_MAGICSOCK_PEERMAP")
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// debugOmitLocalAddresses removes all local interface addresses
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// from magicsock's discovered local endpoints. Used in some tests.
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debugOmitLocalAddresses = envknob.RegisterBool("TS_DEBUG_OMIT_LOCAL_ADDRS")
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// logDerpVerbose logs all received DERP packets, including their
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// full payload.
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logDerpVerbose = envknob.RegisterBool("TS_DEBUG_DERP")
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// debugReSTUNStopOnIdle unconditionally enables the "shut down
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// STUN if magicsock is idle" behavior that normally only triggers
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// on mobile devices, lowers the shutdown interval, and logs more
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// verbosely about idle measurements.
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debugReSTUNStopOnIdle = envknob.RegisterBool("TS_DEBUG_RESTUN_STOP_ON_IDLE")
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// debugAlwaysDERP disables the use of UDP, forcing all peer communication over DERP.
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debugAlwaysDERP = envknob.RegisterBool("TS_DEBUG_ALWAYS_USE_DERP")
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// debugDERPAddr sets the derp address manually, overriding the DERP map from control.
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debugUseDERPAddr = envknob.RegisterString("TS_DEBUG_USE_DERP_ADDR")
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// debugDERPUseHTTP tells clients to connect to DERP via HTTP on port 3340 instead of
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// HTTPS on 443.
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debugUseDERPHTTP = envknob.RegisterBool("TS_DEBUG_USE_DERP_HTTP")
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// debugEnableSilentDisco disables the use of heartbeatTimer on the endpoint struct
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// and attempts to handle disco silently. See issue #540 for details.
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debugEnableSilentDisco = envknob.RegisterBool("TS_DEBUG_ENABLE_SILENT_DISCO")
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// debugSendCallMeUnknownPeer sends a CallMeMaybe to a non-existent destination every
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// time we send a real CallMeMaybe to test the PeerGoneNotHere logic.
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debugSendCallMeUnknownPeer = envknob.RegisterBool("TS_DEBUG_SEND_CALLME_UNKNOWN_PEER")
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// debugBindSocket prints extra debugging about socket rebinding in magicsock.
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debugBindSocket = envknob.RegisterBool("TS_DEBUG_MAGICSOCK_BIND_SOCKET")
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// debugRingBufferMaxSizeBytes overrides the default size of the endpoint
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// history ringbuffer.
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debugRingBufferMaxSizeBytes = envknob.RegisterInt("TS_DEBUG_MAGICSOCK_RING_BUFFER_MAX_SIZE_BYTES")
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// debugEnablePMTUD enables the peer MTU feature, which does path MTU
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// discovery on UDP connections between peers. Currently (2023-09-05)
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// this only turns on the don't fragment bit for the magicsock UDP
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// sockets.
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//
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//lint:ignore U1000 used on Linux/Darwin only
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debugEnablePMTUD = envknob.RegisterOptBool("TS_DEBUG_ENABLE_PMTUD")
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// debugPMTUD prints extra debugging about peer MTU path discovery.
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//
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//lint:ignore U1000 used on Linux/Darwin only
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debugPMTUD = envknob.RegisterBool("TS_DEBUG_PMTUD")
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// debugNeverDirectUDP disables the use of direct UDP connections, forcing
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// all peer communication over DERP or peer relay.
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debugNeverDirectUDP = envknob.RegisterBool("TS_DEBUG_NEVER_DIRECT_UDP")
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// Hey you! Adding a new debugknob? Make sure to stub it out in the
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// debugknobs_stubs.go file too.
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)
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// inTest reports whether the running program is a test that set the
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// IN_TS_TEST environment variable.
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//
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// Unlike the other debug tweakables above, this one needs to be
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// checked every time at runtime, because tests set this after program
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// startup.
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func inTest() bool { return envknob.Bool("IN_TS_TEST") }
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// pretendpoints returns TS_DEBUG_PRETENDPOINT as []AddrPort, if set.
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// See https://github.com/tailscale/tailscale/issues/12578 and
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// https://github.com/tailscale/tailscale/pull/12735.
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//
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// It can be between 0 and 3 comma-separated AddrPorts.
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var pretendpoints = sync.OnceValue(func() (ret []netip.AddrPort) {
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all := envknob.String("TS_DEBUG_PRETENDPOINT")
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const max = 3
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remain := all
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for remain != "" && len(ret) < max {
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var s string
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s, remain, _ = strings.Cut(remain, ",")
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ap, err := netip.ParseAddrPort(s)
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if err != nil {
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log.Printf("ignoring invalid AddrPort %q in TS_DEBUG_PRETENDPOINT %q: %v", s, all, err)
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continue
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}
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ret = append(ret, ap)
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}
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return
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})
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