[ovs-dev] [PATCH 2/3] Combine conjunctions with identical matches into one flow.

Numan Siddique nusiddiq at redhat.com
Mon Oct 28 15:33:01 UTC 2019


On Sat, Oct 26, 2019 at 2:37 AM Mark Michelson <mmichels at redhat.com> wrote:
>
> As stated in previous commits, conjunctive matches have an issue where
> it is possible to install multiple flows that have identical matches.
> This results in ambiguity, and can lead to features (such as ACLs) not
> functioning properly.
>
> This change fixes the problem by combining conjunctions with identical
> matches into a single flow. As an example, in the past we may have had
> something like:
>
> nw_dst=10.0.0.1 actions=conjunction(2,1/2)
> nw_dst=10.0.0.1 actions=conjunction(3,1/2)
>
> This commit changes this into
>
> nw_dst=10.0.0.1 actions=conjunction(2,1/2),conjunction(3,1/2)
>
> This way, there is only a single flow with the proscribed match, and
> there is no ambiguity.
>
> Signed-off-by: Mark Michelson <mmichels at redhat.com>
> ---
>  controller/lflow.c  |  5 ++--
>  controller/ofctrl.c | 73 +++++++++++++++++++++++++++++++++++++++++++++--------
>  controller/ofctrl.h |  6 +++++
>  tests/ovn.at        | 17 +++++--------
>  4 files changed, 79 insertions(+), 22 deletions(-)
>
> diff --git a/controller/lflow.c b/controller/lflow.c
> index e3ed20cd4..34b7c36a6 100644
> --- a/controller/lflow.c
> +++ b/controller/lflow.c
> @@ -736,8 +736,9 @@ consider_logical_flow(
>                  dst->clause = src->clause;
>                  dst->n_clauses = src->n_clauses;
>              }
> -            ofctrl_add_flow(flow_table, ptable, lflow->priority, 0, &m->match,
> -                            &conj, &lflow->header_.uuid);
> +
> +            ofctrl_add_or_append_flow(flow_table, ptable, lflow->priority, 0,
> +                                      &m->match, &conj, &lflow->header_.uuid);
>              ofpbuf_uninit(&conj);
>          }
>      }
> diff --git a/controller/ofctrl.c b/controller/ofctrl.c
> index 3131baff0..afb0036f1 100644
> --- a/controller/ofctrl.c
> +++ b/controller/ofctrl.c
> @@ -69,6 +69,11 @@ struct ovn_flow {
>      uint64_t cookie;
>  };
>
> +static struct ovn_flow *ovn_flow_alloc(uint8_t table_id, uint16_t priority,
> +                                       uint64_t cookie,
> +                                       const struct match *match,
> +                                       const struct ofpbuf *actions,
> +                                       const struct uuid *sb_uuid);
>  static uint32_t ovn_flow_match_hash(const struct ovn_flow *);
>  static struct ovn_flow *ovn_flow_lookup(struct hmap *flow_table,
>                                          const struct ovn_flow *target,
> @@ -657,16 +662,8 @@ ofctrl_check_and_add_flow(struct ovn_desired_flow_table *flow_table,
>                            const struct uuid *sb_uuid,
>                            bool log_duplicate_flow)
>  {
> -    struct ovn_flow *f = xmalloc(sizeof *f);
> -    f->table_id = table_id;
> -    f->priority = priority;
> -    minimatch_init(&f->match, match);
> -    f->ofpacts = xmemdup(actions->data, actions->size);
> -    f->ofpacts_len = actions->size;
> -    f->sb_uuid = *sb_uuid;
> -    f->match_hmap_node.hash = ovn_flow_match_hash(f);
> -    f->uuid_hindex_node.hash = uuid_hash(&f->sb_uuid);
> -    f->cookie = cookie;
> +    struct ovn_flow *f = ovn_flow_alloc(table_id, priority, cookie, match,
> +                                        actions, sb_uuid);
>
>      ovn_flow_log(f, "ofctrl_add_flow");
>
> @@ -721,9 +718,65 @@ ofctrl_add_flow(struct ovn_desired_flow_table *desired_flows,
>      ofctrl_check_and_add_flow(desired_flows, table_id, priority, cookie,
>                                match, actions, sb_uuid, true);
>  }
> +
> +void
> +ofctrl_add_or_append_flow(struct ovn_desired_flow_table *desired_flows,
> +                          uint8_t table_id, uint16_t priority, uint64_t cookie,
> +                          const struct match *match,
> +                          const struct ofpbuf *actions,
> +                          const struct uuid *sb_uuid)
> +{
> +    struct ovn_flow *f = ovn_flow_alloc(table_id, priority, cookie, match,
> +                                        actions, sb_uuid);
> +
> +    ovn_flow_log(f, "ofctrl_add_or_append_flow");
> +
> +    struct ovn_flow *existing;
> +    existing = ovn_flow_lookup(&desired_flows->match_flow_table, f, false);
> +    if (existing) {
> +        /* There's already a flow with this particular match. Append the
> +         * action to that flow rather than adding a new flow
> +         */
> +        uint64_t compound_stub[64 / 8];
> +        struct ofpbuf compound;
> +        ofpbuf_use_stub(&compound, compound_stub, sizeof(compound_stub));
> +        ofpbuf_put(&compound, existing->ofpacts, existing->ofpacts_len);
> +        ofpbuf_put(&compound, f->ofpacts, f->ofpacts_len);

Instead of making use of a stub and copying the existing and new
actions, can't we just
copy the new actions to "existing->ofpacts" using ofpbuf_put() ?

ofpbuf_put() will take care of reallocating the memory if required.

Other than that, this and the 1st patch of this series, looks good to me.

Thanks
Numan

> +
> +        free(existing->ofpacts);
> +        existing->ofpacts = xmemdup(compound.data, compound.size);
> +        existing->ofpacts_len = compound.size;
> +
> +        ovn_flow_destroy(f);
> +    } else {
> +        hmap_insert(&desired_flows->match_flow_table, &f->match_hmap_node,
> +                    f->match_hmap_node.hash);
> +        hindex_insert(&desired_flows->uuid_flow_table, &f->uuid_hindex_node,
> +                      f->uuid_hindex_node.hash);
> +    }
> +}
>
>  /* ovn_flow. */
>
> +static struct ovn_flow *
> +ovn_flow_alloc(uint8_t table_id, uint16_t priority, uint64_t cookie,
> +               const struct match *match, const struct ofpbuf *actions,
> +               const struct uuid *sb_uuid)
> +{
> +    struct ovn_flow *f = xmalloc(sizeof *f);
> +    f->table_id = table_id;
> +    f->priority = priority;
> +    minimatch_init(&f->match, match);
> +    f->ofpacts = xmemdup(actions->data, actions->size);
> +    f->ofpacts_len = actions->size;
> +    f->sb_uuid = *sb_uuid;
> +    f->match_hmap_node.hash = ovn_flow_match_hash(f);
> +    f->uuid_hindex_node.hash = uuid_hash(&f->sb_uuid);
> +    f->cookie = cookie;
> +
> +    return f;
> +}
> +
>  /* Returns a hash of the match key in 'f'. */
>  static uint32_t
>  ovn_flow_match_hash(const struct ovn_flow *f)
> diff --git a/controller/ofctrl.h b/controller/ofctrl.h
> index 1e9ac16b9..21d2ce648 100644
> --- a/controller/ofctrl.h
> +++ b/controller/ofctrl.h
> @@ -70,6 +70,12 @@ void ofctrl_add_flow(struct ovn_desired_flow_table *, uint8_t table_id,
>                       const struct match *, const struct ofpbuf *ofpacts,
>                       const struct uuid *);
>
> +void ofctrl_add_or_append_flow(struct ovn_desired_flow_table *desired_flows,
> +                               uint8_t table_id, uint16_t priority,
> +                               uint64_t cookie, const struct match *match,
> +                               const struct ofpbuf *actions,
> +                               const struct uuid *sb_uuid);
> +
>  void ofctrl_remove_flows(struct ovn_desired_flow_table *, const struct uuid *);
>
>  void ovn_desired_flow_table_init(struct ovn_desired_flow_table *);
> diff --git a/tests/ovn.at b/tests/ovn.at
> index 641a646fc..50d8efeec 100644
> --- a/tests/ovn.at
> +++ b/tests/ovn.at
> @@ -12247,7 +12247,7 @@ ovn-nbctl create Address_Set name=set1 \
>  addresses=\"10.0.0.4\",\"10.0.0.5\",\"10.0.0.6\"
>  ovn-nbctl create Address_Set name=set2 \
>  addresses=\"10.0.0.7\",\"10.0.0.8\",\"10.0.0.9\"
> -ovn-nbctl acl-add ls1 to-lport 1002 \
> +ovn-nbctl acl-add ls1 to-lport 1001 \
>  'ip4 && ip4.src == $set1 && ip4.dst == $set1' allow
>  ovn-nbctl acl-add ls1 to-lport 1001 \
>  'ip4 && ip4.src == $set1 && ip4.dst == $set2' drop
> @@ -12296,7 +12296,7 @@ cat 2.expected > expout
>  $PYTHON "$ovs_srcdir/utilities/ovs-pcap.in" hv1/vif2-tx.pcap > 2.packets
>  AT_CHECK([cat 2.packets], [0], [expout])
>
> -# There should be total of 12 flows present with conjunction action and 2 flows
> +# There should be total of 9 flows present with conjunction action and 2 flows
>  # with conj match. Eg.
>  # table=44, priority=2002,conj_id=2,metadata=0x1 actions=resubmit(,45)
>  # table=44, priority=2001,conj_id=3,metadata=0x1 actions=drop
> @@ -12306,14 +12306,11 @@ AT_CHECK([cat 2.packets], [0], [expout])
>  # priority=2001,ip,metadata=0x1,nw_dst=10.0.0.7 actions=conjunction(3,2/2)
>  # priority=2001,ip,metadata=0x1,nw_dst=10.0.0.9 actions=conjunction(3,2/2)
>  # priority=2001,ip,metadata=0x1,nw_dst=10.0.0.8 actions=conjunction(3,2/2)
> -# priority=2002,ip,metadata=0x1,nw_src=10.0.0.6 actions=conjunction(2,1/2)
> -# priority=2002,ip,metadata=0x1,nw_src=10.0.0.4 actions=conjunction(2,1/2)
> -# priority=2002,ip,metadata=0x1,nw_src=10.0.0.5 actions=conjunction(2,1/2)
> -# priority=2001,ip,metadata=0x1,nw_src=10.0.0.6 actions=conjunction(3,1/2)
> -# priority=2001,ip,metadata=0x1,nw_src=10.0.0.4 actions=conjunction(3,1/2)
> -# priority=2001,ip,metadata=0x1,nw_src=10.0.0.5 actions=conjunction(3,1/2)
> -
> -OVS_WAIT_UNTIL([test 12 = `as hv1 ovs-ofctl dump-flows br-int | \
> +# priority=2002,ip,metadata=0x1,nw_src=10.0.0.6 actions=conjunction(2,1/2),conjunction(3,1/2)
> +# priority=2002,ip,metadata=0x1,nw_src=10.0.0.4 actions=conjunction(2,1/2),conjunction(3,1/2)
> +# priority=2002,ip,metadata=0x1,nw_src=10.0.0.5 actions=conjunction(2,1/2),conjunction(3,1/2)
> +
> +OVS_WAIT_UNTIL([test 9 = `as hv1 ovs-ofctl dump-flows br-int | \
>  grep conjunction | wc -l`])
>  OVS_WAIT_UNTIL([test 2 = `as hv1 ovs-ofctl dump-flows br-int | \
>  grep conj_id | wc -l`])
> --
> 2.14.5
>
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