ref: Add resolver to rpc.RegisterProtocol.
When dialing some of our protocols we get a net.Conn with a different
(protocol,address) pair than what we asked for. E.g. anything that
does DNS resolution will convert the host portion of the address into
an IP address.
This is annoying, because many times we want to use the (protocol,address)
pair as a cache key; i.e. it's used as a VIF cache key. Since the resolved
(protocol,address) is only available after calling the dialer, we
currently waste resources by actually dialing the address, only to
discover the resolved address is already in our cache, and closing the
dialed connection.
This change introduces a Resolver func to rpc.RegisterProtocol that can
be used to perform the DNS lookup without creating a real connection.
For protocols that do not have a resolution step, it is just the identity
function.
closes vanadium/issues#431
MultiPart: 2/2
Change-Id: If9c0de686ea89598fb424fa0f09de91c320a1161
diff --git a/profiles/internal/rpc/stream/manager/manager_test.go b/profiles/internal/rpc/stream/manager/manager_test.go
index ff74b71..5042471 100644
--- a/profiles/internal/rpc/stream/manager/manager_test.go
+++ b/profiles/internal/rpc/stream/manager/manager_test.go
@@ -628,14 +628,12 @@
// We'd like an endpoint that contains an address that's different than the
// one used for the connection. In practice this is awkward to achieve since
// we don't want to listen on ":0" since that will annoy firewalls. Instead we
- // listen on 127.0.0.1 and we fabricate an endpoint that doesn't contain
- // 127.0.0.1 by using ":0" to create it. This leads to an endpoint such that
- // the address encoded in the endpoint (e.g. "0.0.0.0:55324") is different
- // from the address of the connection (e.g. "127.0.0.1:55324").
+ // create a endpoint with "localhost", which will result in an endpoint that
+ // doesn't contain 127.0.0.1.
_, port, _ := net.SplitHostPort(ep.Addr().String())
nep := &inaming.Endpoint{
Protocol: ep.Addr().Network(),
- Address: net.JoinHostPort("", port),
+ Address: net.JoinHostPort("localhost", port),
RID: ep.RoutingID(),
}
@@ -769,10 +767,13 @@
dialer := func(_, _ string, _ time.Duration) (net.Conn, error) {
return nil, fmt.Errorf("tn.Dial")
}
+ resolver := func(_, _ string) (string, string, error) {
+ return "", "", fmt.Errorf("tn.Resolve")
+ }
listener := func(_, _ string) (net.Listener, error) {
return nil, fmt.Errorf("tn.Listen")
}
- rpc.RegisterProtocol("tn", dialer, listener)
+ rpc.RegisterProtocol("tn", dialer, resolver, listener)
_, _, err := server.Listen("tnx", "127.0.0.1:0", principal, blessings)
if err == nil || !strings.Contains(err.Error(), "unknown network: tnx") {
@@ -789,7 +790,7 @@
return net.Listen("tcp", addr)
}
- if got, want := rpc.RegisterProtocol("tn", dialer, listener), true; got != want {
+ if got, want := rpc.RegisterProtocol("tn", dialer, resolver, listener), true; got != want {
t.Errorf("got %t, want %t", got, want)
}
@@ -799,8 +800,8 @@
}
_, err = client.Dial(ep, testutil.NewPrincipal("client"))
- if err == nil || !strings.Contains(err.Error(), "tn.Dial") {
- t.Fatal("expected error is missing (%v)", err)
+ if err == nil || !strings.Contains(err.Error(), "tn.Resolve") {
+ t.Fatalf("expected error is missing (%v)", err)
}
}
@@ -942,17 +943,9 @@
}
go acceptLoop(ln)
- // We'd like an endpoint that contains an address that's different than the
- // one used for the connection. In practice this is awkward to achieve since
- // we don't want to listen on ":0" since that will annoy firewalls. Instead we
- // listen on 127.0.0.1 and we fabricate an endpoint that doesn't contain
- // 127.0.0.1 by using ":0" to create it. This leads to an endpoint such that
- // the address encoded in the endpoint (e.g. "0.0.0.0:55324") is different
- // from the address of the connection (e.g. "127.0.0.1:55324").
- _, port, _ := net.SplitHostPort(ep.Addr().String())
nep := &inaming.Endpoint{
Protocol: ep.Addr().Network(),
- Address: net.JoinHostPort("", port),
+ Address: ep.Addr().String(),
RID: ep.RoutingID(),
}
