appc,ipn/ipnlocal,types/appctype: implement control provided routes

Control can now send down a set of routes along with the domains, and
the routes will be advertised, with any newly overlapped routes being
removed to reduce the size of the routing table.

Fixes tailscale/corp#16833
Signed-off-by: James Tucker <james@tailscale.com>
This commit is contained in:
James Tucker 2024-01-17 11:35:55 -08:00 committed by James Tucker
parent 543e7ed596
commit 24df1ef1ee
5 changed files with 159 additions and 2 deletions

View File

@ -28,6 +28,9 @@ type RouteAdvertiser interface {
// AdvertiseRoute adds a new route advertisement if the route is not already
// being advertised.
AdvertiseRoute(netip.Prefix) error
// UnadvertiseRoute removes a route advertisement.
UnadvertiseRoute(netip.Prefix) error
}
// AppConnector is an implementation of an AppConnector that performs
@ -45,10 +48,14 @@ type AppConnector struct {
// mu guards the fields that follow
mu sync.Mutex
// domains is a map of lower case domain names with no trailing dot, to a
// list of resolved IP addresses.
domains map[string][]netip.Addr
// controlRoutes is the list of routes that were last supplied by control.
controlRoutes []netip.Prefix
// wildcards is the list of domain strings that match subdomains.
wildcards []string
}
@ -97,6 +104,42 @@ func (e *AppConnector) UpdateDomains(domains []string) {
e.logf("handling domains: %v and wildcards: %v", xmaps.Keys(e.domains), e.wildcards)
}
// UpdateRoutes merges the supplied routes into the currently configured routes. The routes supplied
// by control for UpdateRoutes are supplemental to the routes discovered by DNS resolution, but are
// also more often whole ranges. UpdateRoutes will remove any single address routes that are now
// covered by new ranges.
func (e *AppConnector) UpdateRoutes(routes []netip.Prefix) {
e.mu.Lock()
defer e.mu.Unlock()
// If there was no change since the last update, no work to do.
if slices.Equal(e.controlRoutes, routes) {
return
}
nextRoute:
for _, r := range routes {
if err := e.routeAdvertiser.AdvertiseRoute(r); err != nil {
e.logf("failed to advertise route: %v: %v", r, err)
continue
}
for _, addr := range e.domains {
for _, a := range addr {
if r.Contains(a) {
pfx := netip.PrefixFrom(a, a.BitLen())
if err := e.routeAdvertiser.UnadvertiseRoute(pfx); err != nil {
e.logf("failed to unadvertise route: %v: %v", pfx, err)
}
continue nextRoute
}
}
}
}
e.controlRoutes = routes
}
// Domains returns the currently configured domain list.
func (e *AppConnector) Domains() views.Slice[string] {
e.mu.Lock()
@ -132,6 +175,7 @@ func (e *AppConnector) ObserveDNSResponse(res []byte) {
return
}
nextAnswer:
for {
h, err := p.AnswerHeader()
if err == dnsmessage.ErrSectionDone {
@ -206,6 +250,16 @@ func (e *AppConnector) ObserveDNSResponse(res []byte) {
if slices.Contains(addrs, addr) {
continue
}
for _, route := range e.controlRoutes {
if route.Contains(addr) {
// record the new address associated with the domain for faster matching in subsequent
// requests and for diagnostic records.
e.mu.Lock()
e.domains[domain] = append(addrs, addr)
e.mu.Unlock()
continue nextAnswer
}
}
if err := e.routeAdvertiser.AdvertiseRoute(netip.PrefixFrom(addr, addr.BitLen())); err != nil {
e.logf("failed to advertise route for %s: %v: %v", domain, addr, err)
continue

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@ -11,6 +11,7 @@ import (
xmaps "golang.org/x/exp/maps"
"golang.org/x/net/dns/dnsmessage"
"tailscale.com/util/mak"
"tailscale.com/util/must"
)
@ -36,6 +37,30 @@ func TestUpdateDomains(t *testing.T) {
}
}
func TestUpdateRoutes(t *testing.T) {
rc := &routeCollector{}
a := NewAppConnector(t.Logf, rc)
routes := []netip.Prefix{netip.MustParsePrefix("192.0.2.0/24")}
a.UpdateRoutes(routes)
if !slices.EqualFunc(routes, rc.routes, prefixEqual) {
t.Fatalf("got %v, want %v", rc.routes, routes)
}
}
func TestUpdateRoutesUnadvertisesContainedRoutes(t *testing.T) {
rc := &routeCollector{}
a := NewAppConnector(t.Logf, rc)
mak.Set(&a.domains, "example.com", []netip.Addr{netip.MustParseAddr("192.0.2.1")})
rc.routes = []netip.Prefix{netip.MustParsePrefix("192.0.2.1/32")}
routes := []netip.Prefix{netip.MustParsePrefix("192.0.2.0/24")}
a.UpdateRoutes(routes)
if !slices.EqualFunc(routes, rc.routes, prefixEqual) {
t.Fatalf("got %v, want %v", rc.routes, routes)
}
}
func TestDomainRoutes(t *testing.T) {
rc := &routeCollector{}
a := NewAppConnector(t.Logf, rc)
@ -79,7 +104,19 @@ func TestObserveDNSResponse(t *testing.T) {
// don't re-advertise routes that have already been advertised
a.ObserveDNSResponse(dnsResponse("example.com.", "2001:db8::1"))
if !slices.Equal(rc.routes, wantRoutes) {
t.Errorf("got %v; want %v", rc.routes, wantRoutes)
t.Errorf("rc.routes: got %v; want %v", rc.routes, wantRoutes)
}
// don't advertise addresses that are already in a control provided route
pfx := netip.MustParsePrefix("192.0.2.0/24")
a.UpdateRoutes([]netip.Prefix{pfx})
wantRoutes = append(wantRoutes, pfx)
a.ObserveDNSResponse(dnsResponse("example.com.", "192.0.2.1"))
if !slices.Equal(rc.routes, wantRoutes) {
t.Errorf("rc.routes: got %v; want %v", rc.routes, wantRoutes)
}
if !slices.Contains(a.domains["example.com"], netip.MustParseAddr("192.0.2.1")) {
t.Errorf("missing %v from %v", "192.0.2.1", a.domains["exmaple.com"])
}
}
@ -160,3 +197,18 @@ func (rc *routeCollector) AdvertiseRoute(pfx netip.Prefix) error {
rc.routes = append(rc.routes, pfx)
return nil
}
func (rc *routeCollector) UnadvertiseRoute(pfx netip.Prefix) error {
routes := rc.routes
rc.routes = rc.routes[:0]
for _, r := range routes {
if r != pfx {
rc.routes = append(rc.routes, r)
}
}
return nil
}
func prefixEqual(a, b netip.Prefix) bool {
return a.Addr().Compare(b.Addr()) == 0 && a.Bits() == b.Bits()
}

View File

@ -3446,14 +3446,21 @@ func (b *LocalBackend) reconfigAppConnectorLocked(nm *netmap.NetworkMap, prefs i
})
}
var domains []string
var (
domains []string
routes []netip.Prefix
)
for _, attr := range attrs {
if slices.Contains(attr.Connectors, "*") || selfHasTag(attr.Connectors) {
domains = append(domains, attr.Domains...)
routes = append(routes, attr.Routes...)
}
}
slices.Sort(domains)
slices.SortFunc(routes, func(i, j netip.Prefix) int { return i.Addr().Compare(j.Addr()) })
domains = slices.Compact(domains)
routes = slices.Compact(routes)
b.appConnector.UpdateRoutes(routes)
b.appConnector.UpdateDomains(domains)
}
@ -5805,6 +5812,30 @@ func (b *LocalBackend) AdvertiseRoute(ipp netip.Prefix) error {
return err
}
// UnadvertiseRoute implements the appc.RouteAdvertiser interface. It removes
// a route advertisement if one is present in the existing routes.
func (b *LocalBackend) UnadvertiseRoute(ipp netip.Prefix) error {
currentRoutes := b.Prefs().AdvertiseRoutes().AsSlice()
if !slices.Contains(currentRoutes, ipp) {
return nil
}
newRoutes := currentRoutes[:0]
for _, r := range currentRoutes {
if r != ipp {
newRoutes = append(newRoutes, r)
}
}
_, err := b.EditPrefs(&ipn.MaskedPrefs{
Prefs: ipn.Prefs{
AdvertiseRoutes: newRoutes,
},
AdvertiseRoutesSet: true,
})
return err
}
// seamlessRenewalEnabled reports whether seamless key renewals are enabled
// (i.e. we saw our self node with the SeamlessKeyRenewal attr in a netmap).
// This enables beta functionality of renewing node keys without breaking

View File

@ -1169,6 +1169,13 @@ func TestRouteAdvertiser(t *testing.T) {
if routes.Len() != 1 || routes.At(0) != testPrefix {
t.Fatalf("got routes %v, want %v", routes, []netip.Prefix{testPrefix})
}
must.Do(ra.UnadvertiseRoute(testPrefix))
routes = b.Prefs().AdvertiseRoutes()
if routes.Len() != 0 {
t.Fatalf("got routes %v, want none", routes)
}
}
func TestRouterAdvertiserIgnoresContainedRoutes(t *testing.T) {
@ -1352,6 +1359,17 @@ func (rc *routeCollector) AdvertiseRoute(pfx netip.Prefix) error {
return nil
}
func (rc *routeCollector) UnadvertiseRoute(pfx netip.Prefix) error {
routes := rc.routes
rc.routes = rc.routes[:0]
for _, r := range routes {
if r != pfx {
rc.routes = append(rc.routes, r)
}
}
return nil
}
type errorSyspolicyHandler struct {
t *testing.T
err error

View File

@ -66,6 +66,8 @@ type AppConnectorAttr struct {
// Domains enumerates the domains serviced by the specified app connectors.
// Domains can be of the form: example.com, or *.example.com.
Domains []string `json:"domains,omitempty"`
// Routes enumerates the predetermined routes to be advertised by the specified app connectors.
Routes []netip.Prefix `json:"routes,omitempty"`
// Connectors enumerates the app connectors which service these domains.
// These can either be "*" to match any advertising connector, or a
// tag of the form tag:<tag-name>.