ofproto-dpif: Fix up user specifying wrong bridge on "ofproto/trace".

If there is more than one bridge, then it's easy to specify the wrong one
on an ofproto/trace command.  Previously, this would produce surprising
results.  With this commit, "ofproto/trace" should silently fix up the
problem.

It would be nice to not require the user to specify a bridge at all, but
it's theoretically possible to have more than one backer, in which case we
need some way to distinguish, and a bridge name is as good an identifier
as we have.  We could ask the user to specify the datapath_type, I guess,
but that's a less familiar name to most users and it would be a somewhat
gratuitous change in synatx for ofproto/trace.

Bug #15419.
Reported-by: Paul Ingram <paul@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>

diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 862c021..ef5fb63 100644 (file)
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -7647,16 +7647,16 @@ ofproto_unixctl_trace(struct unixctl_conn *conn, int argc, const char *argv[],
                 goto exit;
             }
 
-            /* XXX: Since we allow the user to specify an ofproto, it's
-             * possible they will specify a different ofproto than the one the
-             * port actually belongs too.  Ideally we should simply remove the
-             * ability to specify the ofproto. */
+            /* The user might have specified the wrong ofproto but within the
+             * same backer.  That's OK, ofproto_receive() can find the right
+             * one for us. */
             if (ofproto_receive(ofproto->backer, NULL, odp_key.data,
-                                odp_key.size, &flow, NULL, NULL, NULL,
+                                odp_key.size, &flow, NULL, &ofproto, NULL,
                                 &initial_vals)) {
                 unixctl_command_reply_error(conn, "Invalid flow");
                 goto exit;
             }
+            ds_put_format(&result, "Bridge: %s\n", ofproto->up.name);
         } else {
             char *error_s;