I think you and I might have slightly different models in mind. The
model that I'm after at the moment is that the ofproto generic layer
checks that a set of actions is valid (which can be done without
knowing anything about the hardware) and then the implementation
checks that it can actually implement those valid actions.
I agree that the approach you suggest would work too, and that it
could work with either the model I have in mind or a model where the
implementation has to do all of the validation as well as the
implement-ability checking.
So, I'm inclined to leave it the way I have it, but I remain open to
further discussion.
On Mon, Jul 30, 2012 at 02:45:26PM -0700, Ethan Jackson wrote:
> Looks good to me.
>
> I had a thought but I don't feel strongly about it. What if we made a
> new hook for ofproto implementations:
>
> enum ofperr (*validate_actions)(const struct ofpact ofpacts[], size_t
> ofpacts_len, const struct flow *, int max_ports).
>
> In the ofproto-dpif implementation this would simply pass through to
> ofpacts_check(), but in other implementations it could reject action
> lists which are not implementable by their dpif. This would allow us
> to make *packet_out() and *rule_construct() assume that the actions
> are both valid and implementable. Then they could return void instead
> of an ofperr. Also if we did this, rule_modify_actions() may be
> completely unnecessary. The complete_operation() calls could be
> pulled into ofproto.
>
> At any rate, this seems marginally cleaner to me, but you may feel
> strongly in the other direction in which case the current approach is
> fine.
>
> Ethan
>
> On Fri, Jul 20, 2012 at 4:25 PM, Ben Pfaff <b...@nicira.com> wrote:
> > Signed-off-by: Ben Pfaff <b...@nicira.com>
> > ---
> > ofproto/ofproto-dpif.c | 58
> > ++++++++++++++-----------------------------
> > ofproto/ofproto-provider.h | 14 ++++-------
> > ofproto/ofproto.c | 16 +++++++++---
> > 3 files changed, 36 insertions(+), 52 deletions(-)
> >
> > diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> > index f1d2ae0..44cbd17 100644
> > --- a/ofproto/ofproto-dpif.c
> > +++ b/ofproto/ofproto-dpif.c
> > @@ -4592,13 +4592,6 @@ rule_construct(struct rule *rule_)
> > struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
> > struct rule_dpif *victim;
> > uint8_t table_id;
> > - enum ofperr error;
> > -
> > - error = ofpacts_check(rule->up.ofpacts, rule->up.ofpacts_len,
> > - &rule->up.cr.flow, ofproto->up.max_ports);
> > - if (error) {
> > - return error;
> > - }
> >
> > rule->packet_count = 0;
> > rule->byte_count = 0;
> > @@ -4701,15 +4694,6 @@ static void
> > rule_modify_actions(struct rule *rule_)
> > {
> > struct rule_dpif *rule = rule_dpif_cast(rule_);
> > - struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
> > - enum ofperr error;
> > -
> > - error = ofpacts_check(rule->up.ofpacts, rule->up.ofpacts_len,
> > - &rule->up.cr.flow, ofproto->up.max_ports);
> > - if (error) {
> > - ofoperation_complete(rule->up.pending, error);
> > - return;
> > - }
> >
> > complete_operation(rule);
> > }
> > @@ -6359,36 +6343,32 @@ packet_out(struct ofproto *ofproto_, struct ofpbuf
> > *packet,
> > const struct ofpact *ofpacts, size_t ofpacts_len)
> > {
> > struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
> > - enum ofperr error;
> > + struct odputil_keybuf keybuf;
> > + struct dpif_flow_stats stats;
> >
> > - error = ofpacts_check(ofpacts, ofpacts_len, flow,
> > ofproto->up.max_ports);
> > - if (!error) {
> > - struct odputil_keybuf keybuf;
> > - struct dpif_flow_stats stats;
> > + struct ofpbuf key;
> >
> > - struct ofpbuf key;
> > + struct action_xlate_ctx ctx;
> > + uint64_t odp_actions_stub[1024 / 8];
> > + struct ofpbuf odp_actions;
> >
> > - struct action_xlate_ctx ctx;
> > - uint64_t odp_actions_stub[1024 / 8];
> > - struct ofpbuf odp_actions;
> > + ofpbuf_use_stack(&key, &keybuf, sizeof keybuf);
> > + odp_flow_key_from_flow(&key, flow);
> >
> > - ofpbuf_use_stack(&key, &keybuf, sizeof keybuf);
> > - odp_flow_key_from_flow(&key, flow);
> > + dpif_flow_stats_extract(flow, packet, &stats);
> >
> > - dpif_flow_stats_extract(flow, packet, &stats);
> > + action_xlate_ctx_init(&ctx, ofproto, flow, flow->vlan_tci, NULL,
> > + packet_get_tcp_flags(packet, flow), packet);
> > + ctx.resubmit_stats = &stats;
> >
> > - action_xlate_ctx_init(&ctx, ofproto, flow, flow->vlan_tci, NULL,
> > - packet_get_tcp_flags(packet, flow), packet);
> > - ctx.resubmit_stats = &stats;
> > + ofpbuf_use_stub(&odp_actions,
> > + odp_actions_stub, sizeof odp_actions_stub);
> > + xlate_actions(&ctx, ofpacts, ofpacts_len, &odp_actions);
> > + dpif_execute(ofproto->dpif, key.data, key.size,
> > + odp_actions.data, odp_actions.size, packet);
> > + ofpbuf_uninit(&odp_actions);
> >
> > - ofpbuf_use_stub(&odp_actions,
> > - odp_actions_stub, sizeof odp_actions_stub);
> > - xlate_actions(&ctx, ofpacts, ofpacts_len, &odp_actions);
> > - dpif_execute(ofproto->dpif, key.data, key.size,
> > - odp_actions.data, odp_actions.size, packet);
> > - ofpbuf_uninit(&odp_actions);
> > - }
> > - return error;
> > + return 0;
> > }
> >
> > /* NetFlow. */
> > diff --git a/ofproto/ofproto-provider.h b/ofproto/ofproto-provider.h
> > index 2f62473..80cd55f 100644
> > --- a/ofproto/ofproto-provider.h
> > +++ b/ofproto/ofproto-provider.h
> > @@ -803,11 +803,7 @@ struct ofproto_class {
> > * registers, then it is an error if 'rule->cr' does not wildcard
> > all
> > * registers.
> > *
> > - * - Validate that 'rule->ofpacts' is a sequence of well-formed
> > actions
> > - * that the datapath can correctly implement. If your ofproto
> > - * implementation only implements a subset of the actions that Open
> > - * vSwitch understands, then you should implement your own action
> > - * validation.
> > + * - Validate that the datapath can correctly implement
> > 'rule->ofpacts'.
> > *
> > * - If the rule is valid, update the datapath flow table, adding
> > the new
> > * rule or replacing the existing one.
> > @@ -889,8 +885,8 @@ struct ofproto_class {
> > *
> > * ->rule_modify_actions() should set the following in motion:
> > *
> > - * - Validate that the actions now in 'rule' are well-formed OpenFlow
> > - * actions that the datapath can correctly implement.
> > + * - Validate that the datapath can correctly implement the actions
> > now
> > + * in 'rule'.
> > *
> > * - Update the datapath flow table with the new actions.
> > *
> > @@ -943,8 +939,8 @@ struct ofproto_class {
> > * The caller retains ownership of 'packet' and of 'ofpacts', so
> > * ->packet_out() should not modify or free them.
> > *
> > - * This function must validate that it can implement 'ofpacts'. If
> > not,
> > - * then it should return an OpenFlow error code.
> > + * This function must validate that it can correctly implement
> > 'ofpacts'.
> > + * If not, then it should return an OpenFlow error code.
> > *
> > * 'flow' reflects the flow information for 'packet'. All of the
> > * information in 'flow' is extracted from 'packet', except for
> > diff --git a/ofproto/ofproto.c b/ofproto/ofproto.c
> > index cbcf0d2..17131ca 100644
> > --- a/ofproto/ofproto.c
> > +++ b/ofproto/ofproto.c
> > @@ -2138,10 +2138,13 @@ handle_packet_out(struct ofconn *ofconn, const
> > struct ofp_packet_out *opo)
> > ofpbuf_use_const(payload, po.packet, po.packet_len);
> > }
> >
> > - /* Send out packet. */
> > + /* Verify actions against packet, then send packet if successful. */
> > flow_extract(payload, 0, 0, po.in_port, &flow);
> > - error = p->ofproto_class->packet_out(p, payload, &flow,
> > - po.ofpacts, po.ofpacts_len);
> > + error = ofpacts_check(po.ofpacts, po.ofpacts_len, &flow, p->max_ports);
> > + if (!error) {
> > + error = p->ofproto_class->packet_out(p, payload, &flow,
> > + po.ofpacts, po.ofpacts_len);
> > + }
> > ofpbuf_delete(payload);
> >
> > exit_free_ofpacts:
> > @@ -3237,7 +3240,12 @@ handle_flow_mod(struct ofconn *ofconn, const struct
> > ofp_header *oh)
> > * dropped from OpenFlow in the near future. There is no good
> > error
> > * code, so just state that the flow table is full. */
> > error = OFPERR_OFPFMFC_ALL_TABLES_FULL;
> > - } else {
> > + }
> > + if (!error) {
> > + error = ofpacts_check(fm.ofpacts, fm.ofpacts_len,
> > + &fm.cr.flow, ofproto->max_ports);
> > + }
> > + if (!error) {
> > error = handle_flow_mod__(ofconn_get_ofproto(ofconn), ofconn, &fm,
> > oh);
> > }
> > if (error) {
> > --
> > 1.7.2.5
> >
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