[ovs-dev] [PATCH] ofp-flow: Improve error message when cookie cannot be set.

[Ben Pfaff]

On Tue, Jul 16, 2019 at 03:36:07PM -0700, Gregory Rose wrote:
> 
> On 7/16/2019 10:18 AM, Ben Pfaff wrote:
> > The "cookie" value has two meanings in "ovs-ofctl add-flow", etc.  With
> > a mask, it indicates a match; without a mask, it indicates that the
> > cookie should be set.  In some case, the cookie cannot be set, which may
> > mean that the user meant to indicate a match.  The error message for this
> > case was poor; this improves it.
> > 
> > Suggested-by: "Yi Yang (杨燚)-云服务集团" <yangyi01 at inspur.com>
> > Signed-off-by: Ben Pfaff <blp at ovn.org>
> > ---
> >   lib/ofp-flow.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/ofp-flow.c b/lib/ofp-flow.c
> > index c45afd204f80..ff0396845a4e 100644
> > --- a/lib/ofp-flow.c
> > +++ b/lib/ofp-flow.c
> > @@ -1,5 +1,5 @@
> >   /*
> > - * Copyright (c) 2008-2017 Nicira, Inc.
> > + * Copyright (c) 2008-2017, 2019 Nicira, Inc.
> >    *
> >    * Licensed under the Apache License, Version 2.0 (the "License");
> >    * you may not use this file except in compliance with the License.
> > @@ -1660,7 +1660,9 @@ parse_ofp_str__(struct ofputil_flow_mod *fm, int command, char *string,
> >                       /* No mask means that the cookie is being set. */
> >                       if (command != OFPFC_ADD && command != OFPFC_MODIFY
> >                           && command != OFPFC_MODIFY_STRICT) {
> > -                        return xstrdup("cannot set cookie");
> > +                        return xasprintf("cannot set cookie (to match on a "
> > +                                         "cookie, specify a mask, e.g. "
> > +                                         "cookie=%s/-1)", value);
> >                       }
> >                       error = str_to_be64(value, &fm->new_cookie);
> >                       fm->modify_cookie = true;
> More instructive and helpful error messages are a good thing.
> Reviewed-by: Greg Rose <gvrose8192 at gmail.com>

Thanks, Greg!  I applied this to master.