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Revert "ipn/ipnlocal: allow Split-DNS and default resolvers with WireGuard nodes"

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This reverts commit c7ce4e07e5.

Signed-off-by: James Tucker <james@tailscale.com>
pull/9478/head
James Tucker 1 year ago committed by James Tucker
parent c7ce4e07e5
commit d52ab181c3
2 changed files with 29 additions and 177 deletions
Show Stats Download Patch File Download Diff File

21
ipn/ipnlocal/local.go
Unescape Escape View File

@ -3308,7 +3308,9 @@ func dnsConfigForNetmap(nm *netmap.NetworkMap, peers map[tailcfg.NodeID]tailcfg.
}
addDefault := func(resolvers []*dnstype.Resolver) {
dcfg.DefaultResolvers = append(dcfg.DefaultResolvers, resolvers...)
for _, r := range resolvers {
dcfg.DefaultResolvers = append(dcfg.DefaultResolvers, r)
}
}
// If we're using an exit node and that exit node is new enough (1.19.x+)
@ -3318,17 +3320,14 @@ func dnsConfigForNetmap(nm *netmap.NetworkMap, peers map[tailcfg.NodeID]tailcfg.
return dcfg
}
// If the user has set default resolvers ("override local DNS"), prefer to
// use those resolvers as the default, otherwise if there are WireGuard exit
// node resolvers, use those as the default.
if len(nm.DNS.Resolvers) > 0 {
addDefault(nm.DNS.Resolvers)
} else {
// If we're using an exit node and that exit node is IsWireGuardOnly with
// ExitNodeDNSResolver set, then add that as the default.
if resolvers, ok := wireguardExitNodeDNSResolvers(nm, peers, prefs.ExitNodeID()); ok {
addDefault(resolvers)
}
return dcfg
}
addDefault(nm.DNS.Resolvers)
for suffix, resolvers := range nm.DNS.Routes {
fqdn, err := dnsname.ToFQDN(suffix)
if err != nil {
@ -3343,7 +3342,11 @@ func dnsConfigForNetmap(nm *netmap.NetworkMap, peers map[tailcfg.NodeID]tailcfg.
//
// While we're already populating it, might as well size the
// slice appropriately.
dcfg.Routes[fqdn] = append(dcfg.Routes[fqdn], resolvers...)
dcfg.Routes[fqdn] = make([]*dnstype.Resolver, 0, len(resolvers))
for _, r := range resolvers {
dcfg.Routes[fqdn] = append(dcfg.Routes[fqdn], r)
}
}
// Set FallbackResolvers as the default resolvers in the

181
ipn/ipnlocal/local_test.go
Unescape Escape View File

@ -28,7 +28,6 @@ import (
"tailscale.com/types/logid"
"tailscale.com/types/netmap"
"tailscale.com/types/ptr"
"tailscale.com/util/dnsname"
"tailscale.com/util/set"
"tailscale.com/wgengine"
"tailscale.com/wgengine/filter"
@ -923,191 +922,41 @@ func TestWireguardExitNodeDNSResolvers(t *testing.T) {
nm := &netmap.NetworkMap{}
gotResolvers, gotOK := wireguardExitNodeDNSResolvers(nm, peers, tc.id)
if gotOK != tc.wantOK || !resolversEqual(t, gotResolvers, tc.wantResolvers) {
if gotOK != tc.wantOK || !resolversEqual(gotResolvers, tc.wantResolvers) {
t.Errorf("case: %s: got %v, %v, want %v, %v", tc.name, gotOK, gotResolvers, tc.wantOK, tc.wantResolvers)
}
}
}
func TestDNSConfigForNetmapForExitNodeConfigs(t *testing.T) {
type tc struct {
name string
exitNode tailcfg.StableNodeID
peers []tailcfg.NodeView
dnsConfig *tailcfg.DNSConfig
wantDefaultResolvers []*dnstype.Resolver
wantRoutes map[dnsname.FQDN][]*dnstype.Resolver
}
defaultResolvers := []*dnstype.Resolver{{Addr: "default.example.com"}}
wgResolvers := []*dnstype.Resolver{{Addr: "wg.example.com"}}
peers := []tailcfg.NodeView{
(&tailcfg.Node{
func TestDNSConfigForNetmapForWireguardExitNode(t *testing.T) {
resolvers := []*dnstype.Resolver{{Addr: "dns.example.com"}}
nm := &netmap.NetworkMap{}
peers := map[tailcfg.NodeID]tailcfg.NodeView{
1: (&tailcfg.Node{
ID: 1,
StableID: "wg",
StableID: "1",
IsWireGuardOnly: true,
ExitNodeDNSResolvers: wgResolvers,
Hostinfo: (&tailcfg.Hostinfo{}).View(),
}).View(),
// regular tailscale exit node with DNS capabilities
(&tailcfg.Node{
Cap: 26,
ID: 2,
StableID: "ts",
ExitNodeDNSResolvers: resolvers,
Hostinfo: (&tailcfg.Hostinfo{}).View(),
}).View(),
}
exitDOH := peerAPIBase(&netmap.NetworkMap{Peers: peers}, peers[0]) + "/dns-query"
routes := map[dnsname.FQDN][]*dnstype.Resolver{
"route.example.com.": {{Addr: "route.example.com"}},
}
stringifyRoutes := func(routes map[dnsname.FQDN][]*dnstype.Resolver) map[string][]*dnstype.Resolver {
if routes == nil {
return nil
}
m := make(map[string][]*dnstype.Resolver)
for k, v := range routes {
m[string(k)] = v
prefs := &ipn.Prefs{
ExitNodeID: "1",
CorpDNS: true,
}
return m
}
tests := []tc{
{
name: "noExit/noRoutes/noResolver",
exitNode: "",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{},
wantDefaultResolvers: nil,
wantRoutes: nil,
},
{
name: "tsExit/noRoutes/noResolver",
exitNode: "ts",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{},
wantDefaultResolvers: []*dnstype.Resolver{{Addr: exitDOH}},
wantRoutes: nil,
},
{
name: "tsExit/noRoutes/defaultResolver",
exitNode: "ts",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{Resolvers: defaultResolvers},
wantDefaultResolvers: []*dnstype.Resolver{{Addr: exitDOH}},
wantRoutes: nil,
},
// The following two cases may need to be revisited. For a shared-in
// exit node split-DNS may effectively break, furthermore in the future
// if different nodes observe different DNS configurations, even a
// tailnet local exit node may present a different DNS configuration,
// which may not meet expectations in some use cases.
// In the case where a default resolver is set, the default resolver
// should also perhaps take precedence also.
{
name: "tsExit/routes/noResolver",
exitNode: "ts",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{Routes: stringifyRoutes(routes)},
wantDefaultResolvers: []*dnstype.Resolver{{Addr: exitDOH}},
wantRoutes: nil,
},
{
name: "tsExit/routes/defaultResolver",
exitNode: "ts",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{Routes: stringifyRoutes(routes), Resolvers: defaultResolvers},
wantDefaultResolvers: []*dnstype.Resolver{{Addr: exitDOH}},
wantRoutes: nil,
},
// WireGuard exit nodes with DNS capabilities provide a "fallback" type
// behavior, they have a lower precedence than a default resolver, but
// otherwise allow split-DNS to operate as normal, and are used when
// there is no default resolver.
{
name: "wgExit/noRoutes/noResolver",
exitNode: "wg",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{},
wantDefaultResolvers: wgResolvers,
wantRoutes: nil,
},
{
name: "wgExit/noRoutes/defaultResolver",
exitNode: "wg",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{Resolvers: defaultResolvers},
wantDefaultResolvers: defaultResolvers,
wantRoutes: nil,
},
{
name: "wgExit/routes/defaultResolver",
exitNode: "wg",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{Routes: stringifyRoutes(routes), Resolvers: defaultResolvers},
wantDefaultResolvers: defaultResolvers,
wantRoutes: routes,
},
{
name: "wgExit/routes/noResolver",
exitNode: "wg",
peers: peers,
dnsConfig: &tailcfg.DNSConfig{Routes: stringifyRoutes(routes)},
wantDefaultResolvers: wgResolvers,
wantRoutes: routes,
},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
nm := &netmap.NetworkMap{
Peers: tc.peers,
DNS: *tc.dnsConfig,
}
prefs := &ipn.Prefs{ExitNodeID: tc.exitNode, CorpDNS: true}
got := dnsConfigForNetmap(nm, peersMap(tc.peers), prefs.View(), t.Logf, "")
if !resolversEqual(t, got.DefaultResolvers, tc.wantDefaultResolvers) {
t.Errorf("DefaultResolvers: got %#v, want %#v", got.DefaultResolvers, tc.wantDefaultResolvers)
}
if !routesEqual(t, got.Routes, tc.wantRoutes) {
t.Errorf("Routes: got %#v, want %#v", got.Routes, tc.wantRoutes)
}
})
got := dnsConfigForNetmap(nm, peers, prefs.View(), t.Logf, "")
if !resolversEqual(got.DefaultResolvers, resolvers) {
t.Errorf("got %v, want %v", got.DefaultResolvers, resolvers)
}
}
func resolversEqual(t *testing.T, a, b []*dnstype.Resolver) bool {
if a == nil && b == nil {
return true
}
if a == nil || b == nil {
t.Errorf("resolversEqual: a == nil || b == nil : %#v != %#v", a, b)
return false
}
func resolversEqual(a, b []*dnstype.Resolver) bool {
if len(a) != len(b) {
t.Errorf("resolversEqual: len(a) != len(b) : %#v != %#v", a, b)
return false
}
for i := range a {
if !a[i].Equal(b[i]) {
t.Errorf("resolversEqual: a != b [%d]: %v != %v", i, *a[i], *b[i])
return false
}
}
return true
}
func routesEqual(t *testing.T, a, b map[dnsname.FQDN][]*dnstype.Resolver) bool {
if len(a) != len(b) {
t.Logf("routes: len(a) != len(b): %d != %d", len(a), len(b))
return false
}
for name := range a {
if !resolversEqual(t, a[name], b[name]) {
t.Logf("routes: a != b [%s]: %v != %v", name, a[name], b[name])
return false
}
}

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