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wgengine/magicsock: simplify Geneve-encapsulated disco.Ping handling (#16448)

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Just make [relayManager] always handle it, there's no benefit to
checking bestAddr's.

Also, remove passing of disco.Pong to [relayManager] in
endpoint.handlePongConnLocked(), which is redundant with the callsite in
Conn.handleDiscoMessage(). Conn.handleDiscoMessage() already passes to
[relayManager] if the txID us not known to any [*endpoint].

Updates tailscale/corp#27502

Signed-off-by: Jordan Whited <jordan@tailscale.com>
This commit is contained in:
Jordan Whited
2025-07-07 09:38:10 -07:00
committed by GitHub
parent 540eb05638
commit 3b32cc7586
4 changed files with 63 additions and 86 deletions
Download Patch File Download Diff File Expand all files Collapse all files
wgengine/magicsock/endpoint.go
-7
View File
@@ -1656,13 +1656,6 @@ func (de *endpoint) handlePongConnLocked(m *disco.Pong, di *discoInfo, src epAdd
de.mu.Lock()
defer de.mu.Unlock()
if src.vni.isSet() && src != de.bestAddr.epAddr {
// "src" is not our bestAddr, but [relayManager] might be in the
// middle of probing it, awaiting pong reception. Make it aware.
de.c.relayManager.handleGeneveEncapDiscoMsgNotBestAddr(de.c, m, di, src)
return false
}
isDerp := src.ap.Addr() == tailcfg.DerpMagicIPAddr
sp, ok := de.sentPing[m.TxID]
wgengine/magicsock/magicsock.go
+59 -74
View File
@@ -2103,7 +2103,7 @@ func (c *Conn) handleDiscoMessage(msg []byte, src epAddr, shouldBeRelayHandshake
c.logf("[unexpected] %T packets should not come from a relay server with Geneve control bit set", dm)
return
}
c.relayManager.handleGeneveEncapDiscoMsgNotBestAddr(c, challenge, di, src)
c.relayManager.handleGeneveEncapDiscoMsg(c, challenge, di, src)
return
}
@@ -2125,7 +2125,10 @@ func (c *Conn) handleDiscoMessage(msg []byte, src epAddr, shouldBeRelayHandshake
return true
})
if !knownTxID && src.vni.isSet() {
c.relayManager.handleGeneveEncapDiscoMsgNotBestAddr(c, dm, di, src)
// If it's an unknown TxID, and it's Geneve-encapsulated, then
// make [relayManager] aware. It might be in the middle of probing
// src.
c.relayManager.handleGeneveEncapDiscoMsg(c, dm, di, src)
}
case *disco.CallMeMaybe, *disco.CallMeMaybeVia:
var via *disco.CallMeMaybeVia
@@ -2233,6 +2236,35 @@ func (c *Conn) handlePingLocked(dm *disco.Ping, src epAddr, di *discoInfo, derpN
di.lastPingTime = time.Now()
isDerp := src.ap.Addr() == tailcfg.DerpMagicIPAddr
if src.vni.isSet() {
if isDerp {
c.logf("[unexpected] got Geneve-encapsulated disco ping from %v/%v over DERP", src, derpNodeSrc)
return
}
// [relayManager] is always responsible for handling (replying) to
// Geneve-encapsulated [disco.Ping] messages in the interest of
// simplicity. It might be in the middle of probing src, so it must be
// made aware.
c.relayManager.handleGeneveEncapDiscoMsg(c, dm, di, src)
return
}
// This is a naked [disco.Ping] without a VNI.
// If we can figure out with certainty which node key this disco
// message is for, eagerly update our [epAddr]<>node and disco<>node
// mappings to make p2p path discovery faster in simple
// cases. Without this, disco would still work, but would be
// reliant on DERP call-me-maybe to establish the disco<>node
// mapping, and on subsequent disco handlePongConnLocked to establish
// the IP:port<>disco mapping.
if nk, ok := c.unambiguousNodeKeyOfPingLocked(dm, di.discoKey, derpNodeSrc); ok {
if !isDerp {
c.peerMap.setNodeKeyForEpAddr(src, nk)
}
}
// numNodes tracks how many nodes (node keys) are associated with the disco
// key tied to this inbound ping. Multiple nodes may share the same disco
// key in the case of node sharing and users switching accounts.
@@ -2244,81 +2276,34 @@ func (c *Conn) handlePingLocked(dm *disco.Ping, src epAddr, di *discoInfo, derpN
// a dstKey if the dst ip:port is DERP.
dstKey := derpNodeSrc
switch {
case src.vni.isSet():
if isDerp {
c.logf("[unexpected] got Geneve-encapsulated disco ping from %v/%v over DERP", src, derpNodeSrc)
return
}
var bestEpAddr epAddr
var discoKey key.DiscoPublic
ep, ok := c.peerMap.endpointForEpAddr(src)
if ok {
ep.mu.Lock()
bestEpAddr = ep.bestAddr.epAddr
ep.mu.Unlock()
disco := ep.disco.Load()
if disco != nil {
discoKey = disco.key
}
}
if src == bestEpAddr && discoKey == di.discoKey {
// We have an associated endpoint with src as its bestAddr. Set
// numNodes so we TX a pong further down.
numNodes = 1
} else {
// We have no [endpoint] in the [peerMap] for this relay [epAddr]
// using it as a bestAddr. [relayManager] might be in the middle of
// probing it or attempting to set it as best via
// [endpoint.udpRelayEndpointReady()]. Make [relayManager] aware.
c.relayManager.handleGeneveEncapDiscoMsgNotBestAddr(c, dm, di, src)
return
}
default: // no VNI
// If we can figure out with certainty which node key this disco
// message is for, eagerly update our [epAddr]<>node and disco<>node
// mappings to make p2p path discovery faster in simple
// cases. Without this, disco would still work, but would be
// reliant on DERP call-me-maybe to establish the disco<>node
// mapping, and on subsequent disco handlePongConnLocked to establish
// the IP:port<>disco mapping.
if nk, ok := c.unambiguousNodeKeyOfPingLocked(dm, di.discoKey, derpNodeSrc); ok {
if !isDerp {
c.peerMap.setNodeKeyForEpAddr(src, nk)
}
}
// Remember this route if not present.
var dup bool
if isDerp {
if ep, ok := c.peerMap.endpointForNodeKey(derpNodeSrc); ok {
if ep.addCandidateEndpoint(src.ap, dm.TxID) {
return
}
numNodes = 1
}
} else {
c.peerMap.forEachEndpointWithDiscoKey(di.discoKey, func(ep *endpoint) (keepGoing bool) {
if ep.addCandidateEndpoint(src.ap, dm.TxID) {
dup = true
return false
}
numNodes++
if numNodes == 1 && dstKey.IsZero() {
dstKey = ep.publicKey
}
return true
})
if dup {
// Remember this route if not present.
var dup bool
if isDerp {
if ep, ok := c.peerMap.endpointForNodeKey(derpNodeSrc); ok {
if ep.addCandidateEndpoint(src.ap, dm.TxID) {
return
}
if numNodes > 1 {
// Zero it out if it's ambiguous, so sendDiscoMessage logging
// isn't confusing.
dstKey = key.NodePublic{}
numNodes = 1
}
} else {
c.peerMap.forEachEndpointWithDiscoKey(di.discoKey, func(ep *endpoint) (keepGoing bool) {
if ep.addCandidateEndpoint(src.ap, dm.TxID) {
dup = true
return false
}
numNodes++
if numNodes == 1 && dstKey.IsZero() {
dstKey = ep.publicKey
}
return true
})
if dup {
return
}
if numNodes > 1 {
// Zero it out if it's ambiguous, so sendDiscoMessage logging
// isn't confusing.
dstKey = key.NodePublic{}
}
}
wgengine/magicsock/relaymanager.go
+3 -4
View File
@@ -325,10 +325,9 @@ func (r *relayManager) handleCallMeMaybeVia(ep *endpoint, lastBest addrQuality,
})
}
// handleGeneveEncapDiscoMsgNotBestAddr handles reception of Geneve-encapsulated
// disco messages if they are not associated with any known
// [*endpoint.bestAddr].
func (r *relayManager) handleGeneveEncapDiscoMsgNotBestAddr(conn *Conn, dm disco.Message, di *discoInfo, src epAddr) {
// handleGeneveEncapDiscoMsg handles reception of Geneve-encapsulated disco
// messages.
func (r *relayManager) handleGeneveEncapDiscoMsg(conn *Conn, dm disco.Message, di *discoInfo, src epAddr) {
relayManagerInputEvent(r, nil, &r.rxHandshakeDiscoMsgCh, relayHandshakeDiscoMsgEvent{conn: conn, msg: dm, disco: di.discoKey, from: src.ap, vni: src.vni.get(), at: time.Now()})
}
wgengine/magicsock/relaymanager_test.go
+1 -1
View File
@@ -26,7 +26,7 @@ func TestRelayManagerInitAndIdle(t *testing.T) {
<-rm.runLoopStoppedCh
rm = relayManager{}
rm.handleGeneveEncapDiscoMsgNotBestAddr(&Conn{discoPrivate: key.NewDisco()}, &disco.BindUDPRelayEndpointChallenge{}, &discoInfo{}, epAddr{})
rm.handleGeneveEncapDiscoMsg(&Conn{discoPrivate: key.NewDisco()}, &disco.BindUDPRelayEndpointChallenge{}, &discoInfo{}, epAddr{})
<-rm.runLoopStoppedCh
rm = relayManager{}