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net/tsdial, ipn/ipnlocal: stop using netmap.NetworkMap in Dialer

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tsdial.Dialer.SetNetMap rebuilt an O(n peers) map of MagicDNS names on
every netmap change. As we move toward per-peer incremental deltas,
this becomes quadratic. This removes it and replaces it with
SetResolveMagicDNS, a callback into LocalBackend that looks up
hostnames from nodeBackend's new nodeByName index (populated alongside
nodeByAddr/nodeByKey on both full and delta paths). The index stores
both FQDNs and short names as keys.

This is the same treatment applied to netlog (8f210454d), wglog
(988b0905b), and drive (1d6989408): stop pushing *netmap.NetworkMap
into subsystems and instead have them pull from LocalBackend's live
data via callbacks.

Updates #12542

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Change-Id: I24557ab0c8a27636e08e4779bcfd3ec633db0a78
This commit is contained in:
Brad Fitzpatrick
2026-06-24 13:14:45 -07:00
committed by Brad Fitzpatrick
parent 8dde9b725b
commit aefb1531d1
15 changed files with 522 additions and 359 deletions
Download Patch File Download Diff File Expand all files Collapse all files
ipn/ipnlocal/node_backend.go
+118 -66
View File
@@ -9,6 +9,7 @@ import (
"maps"
"net/netip"
"slices"
"strings"
"sync"
"sync/atomic"
@@ -23,6 +24,7 @@ import (
"tailscale.com/types/dnstype"
"tailscale.com/types/key"
"tailscale.com/types/logger"
"tailscale.com/types/mapx"
"tailscale.com/types/netmap"
"tailscale.com/types/views"
"tailscale.com/util/dnsname"
@@ -125,6 +127,17 @@ type nodeBackend struct {
// It is mutated in place (with mu held) and must not escape the [nodeBackend].
nodeByWGString map[string]tailcfg.NodeID
// nodeByName maps MagicDNS hostnames (lowercase, no trailing dot) to
// node IDs. Both the FQDN and the short name (suffix stripped) are
// keys. It is used by the tsdial MagicDNS resolution callback.
// It is mutated in place (with mu held) and must not escape the [nodeBackend].
nodeByName map[string]tailcfg.NodeID
// extraDNS stores DNS.ExtraRecords A/AAAA entries from the netmap
// (typically service VIPs pushed by control), keyed by canonicalized
// hostname (lowercase, no trailing dot).
extraDNS map[string]netip.Addr
// userProfiles is the live set of user profiles, updated incrementally
// by mergeUserProfiles as deltas arrive. It parallels the peers map:
// netMap.UserProfiles is the frozen snapshot from the last full install,
@@ -507,6 +520,7 @@ func (nb *nodeBackend) SetNetMap(nm *netmap.NetworkMap) {
nb.netMap = nm
nb.updateNodeByAddrLocked()
nb.updateNodeByKeyLocked()
nb.updateNodeByNameLocked()
nb.updatePeersLocked()
nb.signalKeyWaitersForTestLocked()
if nm != nil {
@@ -566,33 +580,21 @@ func (nb *nodeBackend) updateNodeByAddrLocked() {
return
}
// Update the nodeByAddr index.
if nb.nodeByAddr == nil {
nb.nodeByAddr = map[netip.Addr]tailcfg.NodeID{}
}
// First pass, mark everything unwanted.
for k := range nb.nodeByAddr {
nb.nodeByAddr[k] = 0
}
addNode := func(n tailcfg.NodeView) {
addNodeAddr := func(n tailcfg.NodeView) {
for _, ipp := range n.Addresses().All() {
if ipp.IsSingleIP() {
nb.nodeByAddr[ipp.Addr()] = n.ID()
}
}
}
if nm.SelfNode.Valid() {
addNode(nm.SelfNode)
}
for _, p := range nm.Peers {
addNode(p)
}
// Third pass, actually delete the unwanted items.
for k, v := range nb.nodeByAddr {
if v == 0 {
delete(nb.nodeByAddr, k)
mapx.RepopulateNonzero(&nb.nodeByAddr, func() {
if nm.SelfNode.Valid() {
addNodeAddr(nm.SelfNode)
}
}
for _, p := range nm.Peers {
addNodeAddr(p)
}
})
}
func (nb *nodeBackend) updateNodeByKeyLocked() {
@@ -603,40 +605,99 @@ func (nb *nodeBackend) updateNodeByKeyLocked() {
return
}
if nb.nodeByKey == nil {
nb.nodeByKey = map[key.NodePublic]tailcfg.NodeID{}
}
if nb.nodeByWGString == nil {
nb.nodeByWGString = map[string]tailcfg.NodeID{}
}
// First pass, mark everything unwanted.
for k := range nb.nodeByKey {
nb.nodeByKey[k] = 0
}
for k := range nb.nodeByWGString {
nb.nodeByWGString[k] = 0
}
addNode := func(n tailcfg.NodeView) {
nb.nodeByKey[n.Key()] = n.ID()
nb.nodeByWGString[n.Key().WireGuardGoString()] = n.ID()
}
if nm.SelfNode.Valid() {
addNode(nm.SelfNode)
}
for _, p := range nm.Peers {
addNode(p)
}
// Third pass, actually delete the unwanted items.
for k, v := range nb.nodeByKey {
if v == 0 {
delete(nb.nodeByKey, k)
mapx.RepopulateNonzero(&nb.nodeByKey, func() {
if nm.SelfNode.Valid() {
nb.nodeByKey[nm.SelfNode.Key()] = nm.SelfNode.ID()
}
}
for k, v := range nb.nodeByWGString {
if v == 0 {
delete(nb.nodeByWGString, k)
for _, p := range nm.Peers {
nb.nodeByKey[p.Key()] = p.ID()
}
})
mapx.RepopulateNonzero(&nb.nodeByWGString, func() {
if nm.SelfNode.Valid() {
nb.nodeByWGString[nm.SelfNode.Key().WireGuardGoString()] = nm.SelfNode.ID()
}
for _, p := range nm.Peers {
nb.nodeByWGString[p.Key().WireGuardGoString()] = p.ID()
}
})
}
// addNodeNameLocked adds both the FQDN and short-name keys for the given
// node to nb.nodeByName. nb.mu must be held.
func (nb *nodeBackend) addNodeNameLocked(name string, nid tailcfg.NodeID) {
if name == "" {
// We might support name-less nodes in the future; tailscale/corp#43949
return
}
canon := strings.ToLower(strings.TrimSuffix(name, "."))
mak.Set(&nb.nodeByName, canon, nid)
if suffix := nb.netMap.MagicDNSSuffix(); dnsname.HasSuffix(canon, suffix) {
mak.Set(&nb.nodeByName, dnsname.TrimSuffix(canon, suffix), nid)
}
}
// removeNodeNameLocked removes both the FQDN and short-name keys for the
// given node from nb.nodeByName. nb.mu must be held.
func (nb *nodeBackend) removeNodeNameLocked(name string) {
if name == "" {
// We might support name-less nodes in the future; tailscale/corp#43949
return
}
canon := strings.ToLower(strings.TrimSuffix(name, "."))
delete(nb.nodeByName, canon)
if suffix := nb.netMap.MagicDNSSuffix(); dnsname.HasSuffix(canon, suffix) {
delete(nb.nodeByName, dnsname.TrimSuffix(canon, suffix))
}
}
func (nb *nodeBackend) updateNodeByNameLocked() {
nm := nb.netMap
if nm == nil {
nb.nodeByName = nil
nb.extraDNS = nil
return
}
mapx.RepopulateNonzero(&nb.nodeByName, func() {
if nm.SelfNode.Valid() {
nb.addNodeNameLocked(nm.SelfNode.Name(), nm.SelfNode.ID())
}
for _, p := range nm.Peers {
nb.addNodeNameLocked(p.Name(), p.ID())
}
})
// Rebuild extraDNS from DNS.ExtraRecords (service VIPs, etc).
nb.extraDNS = nil
for _, rec := range nm.DNS.ExtraRecords {
if rec.Type != "" {
continue
}
ip, err := netip.ParseAddr(rec.Value)
if err != nil {
continue
}
mak.Set(&nb.extraDNS, strings.ToLower(strings.TrimSuffix(rec.Name, ".")), ip)
}
}
// NodeByName returns the node ID for a MagicDNS hostname. The input
// must be lowercase with no trailing dot; both short names ("foo") and
// FQDNs ("foo.tail-scale.ts.net") are accepted.
func (nb *nodeBackend) NodeByName(hostname string) (_ tailcfg.NodeID, ok bool) {
nb.mu.Lock()
defer nb.mu.Unlock()
nid, ok := nb.nodeByName[hostname]
return nid, ok
}
// ExtraDNSByName returns the IP for a DNS.ExtraRecords entry (e.g. service VIPs).
func (nb *nodeBackend) ExtraDNSByName(hostname string) (_ netip.Addr, ok bool) {
nb.mu.Lock()
defer nb.mu.Unlock()
ip, ok := nb.extraDNS[hostname]
return ip, ok
}
func (nb *nodeBackend) updatePeersLocked() {
@@ -646,22 +707,11 @@ func (nb *nodeBackend) updatePeersLocked() {
return
}
// First pass, mark everything unwanted.
for k := range nb.peers {
nb.peers[k] = tailcfg.NodeView{}
}
// Second pass, add everything wanted.
for _, p := range nm.Peers {
mak.Set(&nb.peers, p.ID(), p)
}
// Third pass, remove deleted things.
for k, v := range nb.peers {
if !v.Valid() {
delete(nb.peers, k)
mapx.RepopulateNonzero(&nb.peers, func() {
for _, p := range nm.Peers {
nb.peers[p.ID()] = p
}
}
})
}
// setPacketFilter stores the live packet filter rules and parsed
@@ -717,6 +767,7 @@ func (nb *nodeBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
}
mak.Set(&nb.nodeByKey, m.Node.Key(), nid)
mak.Set(&nb.nodeByWGString, m.Node.Key().WireGuardGoString(), nid)
nb.addNodeNameLocked(m.Node.Name(), nid)
continue
case netmap.NodeMutationRemove:
nid := m.NodeIDBeingMutated()
@@ -728,6 +779,7 @@ func (nb *nodeBackend) UpdateNetmapDelta(muts []netmap.NodeMutation) (handled bo
}
delete(nb.nodeByKey, old.Key())
delete(nb.nodeByWGString, old.Key().WireGuardGoString())
nb.removeNodeNameLocked(old.Name())
delete(nb.peers, nid)
}
continue