[ovs-dev,v10] Improved Packet Drop Statistics in OVS

Currently OVS maintains explicit packet drop/error counters only on port level.
Packets that are dropped as part of normal OpenFlow processing are counted in flow stats of “drop” flows or as table misses in table stats.
These can only be interpreted by controllers that know the semantics of the configured OpenFlow pipeline. Without that knowledge, it is impossible for an OVS user to obtain e.g. the total number of packets dropped due to OpenFlow rules.

Furthermore, there are numerous other reasons for which packets can be dropped by OVS slow path that are not related to the OpenFlow pipeline.
The generated datapath flow entries include a drop action to avoid further expensive upcalls to the slow path, but subsequent packets dropped by the datapath are not accounted anywhere.

Finally, the datapath itself drops packets in certain error situations.
Also, these drops are today not accounted for.

This makes it difficult for OVS users to monitor packet drop in an OVS instance and to alert a management system in case of a unexpected increase of such drops. Also OVS trouble-shooters face difficulties in analysing packet drops.

With this patch we implement following changes to address the issues mentioned above.

1. Identify and account all the silent packet drop scenarios

2. Display these drops in ovs-appctl coverage/show

A detailed presentation on this was presented at OvS conference 2017 and link for the corresponding presentation is available at:

https://www.slideshare.net/LF_OpenvSwitch/lfovs17troubleshooting-the-data-plane-in-ovs-82280329

Co-authored-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
Co-authored-by: Keshav Gupta <keshugupta1@gmail.com>
Signed-off-by: Anju Thomas <anju.thomas@ericsson.com>
Signed-off-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
Signed-off-by: Keshav Gupta <keshugupta1@gmail.com>
---
 datapath/linux/compat/include/linux/openvswitch.h |   1 +
 lib/dpif-netdev.c                                 |  46 ++++-
 lib/dpif.c                                        |   7 +
 lib/dpif.h                                        |   4 +
 lib/odp-execute.c                                 |  78 ++++++++
 lib/odp-util.c                                    |   9 +
 ofproto/ofproto-dpif-ipfix.c                      |   1 +
 ofproto/ofproto-dpif-sflow.c                      |   1 +
 ofproto/ofproto-dpif-xlate.c                      |  34 +++-
 ofproto/ofproto-dpif-xlate.h                      |   3 +
 ofproto/ofproto-dpif.c                            |   7 +
 ofproto/ofproto-dpif.h                            |   8 +-
 tests/automake.mk                                 |   3 +-
 tests/dpif-netdev.at                              |   8 +
 tests/drop-stats.at                               | 211 ++++++++++++++++++++++
 tests/ofproto-dpif.at                             |   2 +-
 tests/tunnel-push-pop.at                          |  29 ++-
 tests/tunnel.at                                   |  14 +-
 18 files changed, 455 insertions(+), 11 deletions(-)
 create mode 100644 tests/drop-stats.at

On 6/6/2019 10:27 PM, Anju Thomas wrote:
> Currently OVS maintains explicit packet drop/error counters only on port level.
> Packets that are dropped as part of normal OpenFlow processing are counted in flow stats of “drop” flows or as table misses in table stats.
> These can only be interpreted by controllers that know the semantics of the configured OpenFlow pipeline. Without that knowledge, it is impossible for an OVS user to obtain e.g. the total number of packets dropped due to OpenFlow rules.
>
> Furthermore, there are numerous other reasons for which packets can be dropped by OVS slow path that are not related to the OpenFlow pipeline.
> The generated datapath flow entries include a drop action to avoid further expensive upcalls to the slow path, but subsequent packets dropped by the datapath are not accounted anywhere.
>
> Finally, the datapath itself drops packets in certain error situations.
> Also, these drops are today not accounted for.
>
> This makes it difficult for OVS users to monitor packet drop in an OVS instance and to alert a management system in case of a unexpected increase of such drops. Also OVS trouble-shooters face difficulties in analysing packet drops.
>
> With this patch we implement following changes to address the issues mentioned above.
>
> 1. Identify and account all the silent packet drop scenarios
>
> 2. Display these drops in ovs-appctl coverage/show
>
> A detailed presentation on this was presented at OvS conference 2017 and link for the corresponding presentation is available at:
>
> https://www.slideshare.net/LF_OpenvSwitch/lfovs17troubleshooting-the-data-plane-in-ovs-82280329
>
> Co-authored-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
> Co-authored-by: Keshav Gupta <keshugupta1@gmail.com>
> Signed-off-by: Anju Thomas <anju.thomas@ericsson.com>
> Signed-off-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
> Signed-off-by: Keshav Gupta <keshugupta1@gmail.com>

Hi Anju et al,

I am going to review and test this patch, however, I do have a request 
just below...

> ---

Here, below the three dash line just above, there should be an 
accounting of all changes from version 1 of
this patch set to version 10.  Something like this:

v9 -> v10 Changed something due to review comments etc...
v8 -> v9 Describe changes from v8 to v9 etc...

I think it's essential to reviewers to understand the previous patches 
and their evolution to the current patch.

Thanks,

- Greg

>   datapath/linux/compat/include/linux/openvswitch.h |   1 +
>   lib/dpif-netdev.c                                 |  46 ++++-
>   lib/dpif.c                                        |   7 +
>   lib/dpif.h                                        |   4 +
>   lib/odp-execute.c                                 |  78 ++++++++
>   lib/odp-util.c                                    |   9 +
>   ofproto/ofproto-dpif-ipfix.c                      |   1 +
>   ofproto/ofproto-dpif-sflow.c                      |   1 +
>   ofproto/ofproto-dpif-xlate.c                      |  34 +++-
>   ofproto/ofproto-dpif-xlate.h                      |   3 +
>   ofproto/ofproto-dpif.c                            |   7 +
>   ofproto/ofproto-dpif.h                            |   8 +-
>   tests/automake.mk                                 |   3 +-
>   tests/dpif-netdev.at                              |   8 +
>   tests/drop-stats.at                               | 211 ++++++++++++++++++++++
>   tests/ofproto-dpif.at                             |   2 +-
>   tests/tunnel-push-pop.at                          |  29 ++-
>   tests/tunnel.at                                   |  14 +-
>   18 files changed, 455 insertions(+), 11 deletions(-)
>   create mode 100644 tests/drop-stats.at
>
> diff --git a/datapath/linux/compat/include/linux/openvswitch.h b/datapath/linux/compat/include/linux/openvswitch.h
> index 65a003a..2de702e 100644
> --- a/datapath/linux/compat/include/linux/openvswitch.h
> +++ b/datapath/linux/compat/include/linux/openvswitch.h
> @@ -985,6 +985,7 @@ enum ovs_action_attr {
>   	OVS_ACTION_ATTR_METER,        /* u32 meter number. */
>   	OVS_ACTION_ATTR_CLONE,        /* Nested OVS_CLONE_ATTR_*.  */
>   	OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested OVS_CHECK_PKT_LEN_ATTR_*. */
> +    OVS_ACTION_ATTR_DROP,
>   
>   #ifndef __KERNEL__
>   	OVS_ACTION_ATTR_TUNNEL_PUSH,   /* struct ovs_action_push_tnl*/
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 5a6f2ab..ec72403 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -101,6 +101,17 @@ enum { MAX_METERS = 65536 };    /* Maximum number of meters. */
>   enum { MAX_BANDS = 8 };         /* Maximum number of bands / meter. */
>   enum { N_METER_LOCKS = 64 };    /* Maximum number of meters. */
>   
> +COVERAGE_DEFINE(datapath_drop_meter);
> +COVERAGE_DEFINE(datapath_drop_upcall_error);
> +COVERAGE_DEFINE(datapath_drop_lock_error);
> +COVERAGE_DEFINE(datapath_drop_userspace_action_error);
> +COVERAGE_DEFINE(datapath_drop_tunnel_push_error);
> +COVERAGE_DEFINE(datapath_drop_tunnel_pop_error);
> +COVERAGE_DEFINE(datapath_drop_recirc_error);
> +COVERAGE_DEFINE(datapath_drop_invalid_port);
> +COVERAGE_DEFINE(datapath_drop_invalid_tnl_port);
> +COVERAGE_DEFINE(datapath_drop_rx_invalid_packet);
> +
>   /* Protects against changes to 'dp_netdevs'. */
>   static struct ovs_mutex dp_netdev_mutex = OVS_MUTEX_INITIALIZER;
>   
> @@ -5646,7 +5657,7 @@ dp_netdev_run_meter(struct dp_netdev *dp, struct dp_packet_batch *packets_,
>               band = &meter->bands[exceeded_band[j]];
>               band->packet_count += 1;
>               band->byte_count += dp_packet_size(packet);
> -
> +            COVERAGE_INC(datapath_drop_meter);
>               dp_packet_delete(packet);
>           } else {
>               /* Meter accepts packet. */
> @@ -6402,6 +6413,7 @@ dfc_processing(struct dp_netdev_pmd_thread *pmd,
>   
>           if (OVS_UNLIKELY(dp_packet_size(packet) < ETH_HEADER_LEN)) {
>               dp_packet_delete(packet);
> +            COVERAGE_INC(datapath_drop_rx_invalid_packet);
>               continue;
>           }
>   
> @@ -6521,6 +6533,7 @@ handle_packet_upcall(struct dp_netdev_pmd_thread *pmd,
>                                put_actions);
>       if (OVS_UNLIKELY(error && error != ENOSPC)) {
>           dp_packet_delete(packet);
> +        COVERAGE_INC(datapath_drop_upcall_error);
>           return error;
>       }
>   
> @@ -6651,6 +6664,7 @@ fast_path_processing(struct dp_netdev_pmd_thread *pmd,
>           DP_PACKET_BATCH_FOR_EACH (i, packet, packets_) {
>               if (OVS_UNLIKELY(!rules[i])) {
>                   dp_packet_delete(packet);
> +                COVERAGE_INC(datapath_drop_lock_error);
>                   upcall_fail_cnt++;
>               }
>           }
> @@ -6920,6 +6934,7 @@ dp_execute_userspace_action(struct dp_netdev_pmd_thread *pmd,
>                                     actions->data, actions->size);
>       } else if (should_steal) {
>           dp_packet_delete(packet);
> +        COVERAGE_INC(datapath_drop_userspace_action_error);
>       }
>   }
>   
> @@ -6934,6 +6949,7 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>       struct dp_netdev *dp = pmd->dp;
>       int type = nl_attr_type(a);
>       struct tx_port *p;
> +    uint32_t packet_count, packet_dropped;
>   
>       switch ((enum ovs_action_attr)type) {
>       case OVS_ACTION_ATTR_OUTPUT:
> @@ -6975,6 +6991,9 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>                   dp_packet_batch_add(&p->output_pkts, packet);
>               }
>               return;
> +        } else {
> +            COVERAGE_ADD(datapath_drop_invalid_port,
> +                            dp_packet_batch_size(packets_));
>           }
>           break;
>   
> @@ -6984,10 +7003,16 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>                * the ownership of these packets. Thus, we can avoid performing
>                * the action, because the caller will not use the result anyway.
>                * Just break to free the batch. */
> +            COVERAGE_ADD(datapath_drop_tunnel_push_error,
> +                            dp_packet_batch_size(packets_));
>               break;
>           }
>           dp_packet_batch_apply_cutlen(packets_);
> -        push_tnl_action(pmd, a, packets_);
> +        packet_count = dp_packet_batch_size(packets_);
> +        if (push_tnl_action(pmd, a, packets_)) {
> +            COVERAGE_ADD(datapath_drop_tunnel_push_error,
> +                            packet_count);
> +        }
>           return;
>   
>       case OVS_ACTION_ATTR_TUNNEL_POP:
> @@ -7007,7 +7032,13 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>   
>                   dp_packet_batch_apply_cutlen(packets_);
>   
> +                packet_count = dp_packet_batch_size(packets_);
>                   netdev_pop_header(p->port->netdev, packets_);
> +                packet_dropped = packet_count - packets_->count;
> +                if (packet_dropped) {
> +                    COVERAGE_ADD(datapath_drop_tunnel_pop_error,
> +                                     packet_dropped);
> +                }
>                   if (dp_packet_batch_is_empty(packets_)) {
>                       return;
>                   }
> @@ -7022,6 +7053,11 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>                   (*depth)--;
>                   return;
>               }
> +            COVERAGE_ADD(datapath_drop_invalid_tnl_port,
> +                            dp_packet_batch_size(packets_));
> +        } else {
> +            COVERAGE_ADD(datapath_drop_recirc_error,
> +                            dp_packet_batch_size(packets_));
>           }
>           break;
>   
> @@ -7066,6 +7102,9 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>   
>               return;
>           }
> +        COVERAGE_ADD(datapath_drop_lock_error,
> +                        dp_packet_batch_size(packets_));
> +
>           break;
>   
>       case OVS_ACTION_ATTR_RECIRC:
> @@ -7089,6 +7128,8 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>               return;
>           }
>   
> +        COVERAGE_ADD(datapath_drop_recirc_error,
> +                        dp_packet_batch_size(packets_));
>           VLOG_WARN("Packet dropped. Max recirculation depth exceeded.");
>           break;
>   
> @@ -7242,6 +7283,7 @@ dp_execute_cb(void *aux_, struct dp_packet_batch *packets_,
>       case OVS_ACTION_ATTR_POP_NSH:
>       case OVS_ACTION_ATTR_CT_CLEAR:
>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +    case OVS_ACTION_ATTR_DROP:
>       case __OVS_ACTION_ATTR_MAX:
>           OVS_NOT_REACHED();
>       }
> diff --git a/lib/dpif.c b/lib/dpif.c
> index a18fb1b..112e9d1 100644
> --- a/lib/dpif.c
> +++ b/lib/dpif.c
> @@ -1267,6 +1267,7 @@ dpif_execute_helper_cb(void *aux_, struct dp_packet_batch *packets_,
>       case OVS_ACTION_ATTR_CT_CLEAR:
>       case OVS_ACTION_ATTR_UNSPEC:
>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +    case OVS_ACTION_ATTR_DROP:
>       case __OVS_ACTION_ATTR_MAX:
>           OVS_NOT_REACHED();
>       }
> @@ -1872,6 +1873,12 @@ dpif_supports_tnl_push_pop(const struct dpif *dpif)
>       return dpif_is_netdev(dpif);
>   }
>   
> +bool
> +dpif_supports_explicit_drop_action(const struct dpif *dpif) {
> +    return dpif_is_netdev(dpif);
> +}
> +
> +
>   /* Meters */
>   void
>   dpif_meter_get_features(const struct dpif *dpif,
> diff --git a/lib/dpif.h b/lib/dpif.h
> index 475d5a6..4b9a434 100644
> --- a/lib/dpif.h
> +++ b/lib/dpif.h
> @@ -888,6 +888,10 @@ int dpif_get_pmds_for_port(const struct dpif * dpif, odp_port_t port_no,
>   
>   char *dpif_get_dp_version(const struct dpif *);
>   bool dpif_supports_tnl_push_pop(const struct dpif *);
> +bool dpif_supports_explicit_drop_action(const struct dpif *);
> +int dpif_show_drop_stats_support(struct dpif *dpif, bool detail,
> +                          struct ds *reply);
> +
>   
>   /* Log functions. */
>   struct vlog_module;
> diff --git a/lib/odp-execute.c b/lib/odp-execute.c
> index 563ad1d..e243e89 100644
> --- a/lib/odp-execute.c
> +++ b/lib/odp-execute.c
> @@ -25,6 +25,7 @@
>   #include <stdlib.h>
>   #include <string.h>
>   
> +#include "coverage.h"
>   #include "dp-packet.h"
>   #include "dpif.h"
>   #include "netlink.h"
> @@ -36,6 +37,72 @@
>   #include "util.h"
>   #include "csum.h"
>   #include "conntrack.h"
> +#include "ofproto/ofproto-dpif-xlate.h"
> +#include "openvswitch/vlog.h"
> +
> +VLOG_DEFINE_THIS_MODULE(odp_execute)
> +COVERAGE_DEFINE(datapath_drop_sample_error);
> +COVERAGE_DEFINE(datapath_drop_nsh_decap_error);
> +COVERAGE_DEFINE(drop_action_of_pipeline);
> +COVERAGE_DEFINE(drop_action_bridge_not_found);
> +COVERAGE_DEFINE(drop_action_recursion_too_deep);
> +COVERAGE_DEFINE(drop_action_too_many_resubmit);
> +COVERAGE_DEFINE(drop_action_stack_too_deep);
> +COVERAGE_DEFINE(drop_action_no_recirculation_context);
> +COVERAGE_DEFINE(drop_action_recirculation_conflict);
> +COVERAGE_DEFINE(drop_action_too_many_mpls_labels);
> +COVERAGE_DEFINE(drop_action_invalid_tunnel_metadata);
> +COVERAGE_DEFINE(drop_action_unsupported_packet_type);
> +COVERAGE_DEFINE(drop_action_congestion);
> +COVERAGE_DEFINE(drop_action_forwarding_disabled);
> +
> +static void
> +dp_update_drop_action_counter(enum xlate_error drop_reason,
> +                                 int delta) {
> +   static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +
> +   switch (drop_reason) {
> +   case XLATE_OK:
> +        COVERAGE_ADD(drop_action_of_pipeline, delta);
> +        break;
> +   case XLATE_BRIDGE_NOT_FOUND:
> +        COVERAGE_ADD(drop_action_bridge_not_found, delta);
> +        break;
> +   case XLATE_RECURSION_TOO_DEEP:
> +        COVERAGE_ADD(drop_action_recursion_too_deep, delta);
> +        break;
> +   case XLATE_TOO_MANY_RESUBMITS:
> +        COVERAGE_ADD(drop_action_too_many_resubmit, delta);
> +        break;
> +   case XLATE_STACK_TOO_DEEP:
> +        COVERAGE_ADD(drop_action_stack_too_deep, delta);
> +        break;
> +   case XLATE_NO_RECIRCULATION_CONTEXT:
> +        COVERAGE_ADD(drop_action_no_recirculation_context, delta);
> +        break;
> +   case XLATE_RECIRCULATION_CONFLICT:
> +        COVERAGE_ADD(drop_action_recirculation_conflict, delta);
> +        break;
> +   case XLATE_TOO_MANY_MPLS_LABELS:
> +        COVERAGE_ADD(drop_action_too_many_mpls_labels, delta);
> +        break;
> +   case XLATE_INVALID_TUNNEL_METADATA:
> +        COVERAGE_ADD(drop_action_invalid_tunnel_metadata, delta);
> +        break;
> +   case XLATE_UNSUPPORTED_PACKET_TYPE:
> +        COVERAGE_ADD(drop_action_unsupported_packet_type, delta);
> +        break;
> +   case XLATE_CONGESTION_DROP:
> +        COVERAGE_ADD(drop_action_congestion, delta);
> +        break;
> +   case XLATE_FORWARDING_DISABLED:
> +        COVERAGE_ADD(drop_action_forwarding_disabled, delta);
> +        break;
> +   case XLATE_MAX:
> +   default:
> +        VLOG_ERR_RL(&rl, "Invalid Drop reason type:%d", drop_reason);
> +   }
> +}
>   
>   /* Masked copy of an ethernet address. 'src' is already properly masked. */
>   static void
> @@ -621,6 +688,7 @@ odp_execute_sample(void *dp, struct dp_packet *packet, bool steal,
>           case OVS_SAMPLE_ATTR_PROBABILITY:
>               if (random_uint32() >= nl_attr_get_u32(a)) {
>                   if (steal) {
> +                    COVERAGE_ADD(datapath_drop_sample_error, 1);
>                       dp_packet_delete(packet);
>                   }
>                   return;
> @@ -749,6 +817,7 @@ requires_datapath_assistance(const struct nlattr *a)
>       case OVS_ACTION_ATTR_POP_NSH:
>       case OVS_ACTION_ATTR_CT_CLEAR:
>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +    case OVS_ACTION_ATTR_DROP:
>           return false;
>   
>       case OVS_ACTION_ATTR_UNSPEC:
> @@ -965,6 +1034,7 @@ odp_execute_actions(void *dp, struct dp_packet_batch *batch, bool steal,
>                   if (pop_nsh(packet)) {
>                       dp_packet_batch_refill(batch, packet, i);
>                   } else {
> +                    COVERAGE_INC(datapath_drop_nsh_decap_error);
>                       dp_packet_delete(packet);
>                   }
>               }
> @@ -989,6 +1059,14 @@ odp_execute_actions(void *dp, struct dp_packet_batch *batch, bool steal,
>               }
>               break;
>   
> +        case OVS_ACTION_ATTR_DROP:{
> +            const enum xlate_error *drop_reason = nl_attr_get(a);
> +            if (*drop_reason < XLATE_MAX) {
> +                 dp_update_drop_action_counter(*drop_reason, batch->count);
> +            }
> +            dp_packet_delete_batch(batch, steal);
> +            return;
> +        }
>           case OVS_ACTION_ATTR_OUTPUT:
>           case OVS_ACTION_ATTR_TUNNEL_PUSH:
>           case OVS_ACTION_ATTR_TUNNEL_POP:
> diff --git a/lib/odp-util.c b/lib/odp-util.c
> index 3a28877..0dbb6d9 100644
> --- a/lib/odp-util.c
> +++ b/lib/odp-util.c
> @@ -44,6 +44,7 @@
>   #include "openvswitch/vlog.h"
>   #include "openvswitch/match.h"
>   #include "odp-netlink-macros.h"
> +#include "ofproto/ofproto-dpif-xlate.h"
>   
>   VLOG_DEFINE_THIS_MODULE(odp_util);
>   
> @@ -140,6 +141,7 @@ odp_action_len(uint16_t type)
>       case OVS_ACTION_ATTR_PUSH_NSH: return ATTR_LEN_VARIABLE;
>       case OVS_ACTION_ATTR_POP_NSH: return 0;
>       case OVS_ACTION_ATTR_CHECK_PKT_LEN: return ATTR_LEN_VARIABLE;
> +    case OVS_ACTION_ATTR_DROP: return sizeof(enum xlate_error);
>   
>       case OVS_ACTION_ATTR_UNSPEC:
>       case __OVS_ACTION_ATTR_MAX:
> @@ -1230,6 +1232,9 @@ format_odp_action(struct ds *ds, const struct nlattr *a,
>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>           format_odp_check_pkt_len_action(ds, a, portno_names);
>           break;
> +    case OVS_ACTION_ATTR_DROP:
> +        ds_put_cstr(ds, "drop");
> +        break;
>       case OVS_ACTION_ATTR_UNSPEC:
>       case __OVS_ACTION_ATTR_MAX:
>       default:
> @@ -2547,8 +2552,12 @@ odp_actions_from_string(const char *s, const struct simap *port_names,
>                           struct ofpbuf *actions)
>   {
>       size_t old_size;
> +    enum xlate_error drop_action;
>   
>       if (!strcasecmp(s, "drop")) {
> +        drop_action = XLATE_OK;
> +        nl_msg_put_unspec(actions, OVS_ACTION_ATTR_DROP,
> +                          &drop_action, sizeof drop_action);
>           return 0;
>       }
>   
> diff --git a/ofproto/ofproto-dpif-ipfix.c b/ofproto/ofproto-dpif-ipfix.c
> index b8bd1b8..b413768 100644
> --- a/ofproto/ofproto-dpif-ipfix.c
> +++ b/ofproto/ofproto-dpif-ipfix.c
> @@ -3016,6 +3016,7 @@ dpif_ipfix_read_actions(const struct flow *flow,
>           case OVS_ACTION_ATTR_POP_NSH:
>           case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>           case OVS_ACTION_ATTR_UNSPEC:
> +        case OVS_ACTION_ATTR_DROP:
>           case __OVS_ACTION_ATTR_MAX:
>           default:
>               break;
> diff --git a/ofproto/ofproto-dpif-sflow.c b/ofproto/ofproto-dpif-sflow.c
> index 03bd763..387e9b5 100644
> --- a/ofproto/ofproto-dpif-sflow.c
> +++ b/ofproto/ofproto-dpif-sflow.c
> @@ -1224,6 +1224,7 @@ dpif_sflow_read_actions(const struct flow *flow,
>           case OVS_ACTION_ATTR_POP_NSH:
>           case OVS_ACTION_ATTR_UNSPEC:
>           case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +        case OVS_ACTION_ATTR_DROP:
>           case __OVS_ACTION_ATTR_MAX:
>           default:
>               break;
> diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
> index 5cee37f..1a9c6fe 100644
> --- a/ofproto/ofproto-dpif-xlate.c
> +++ b/ofproto/ofproto-dpif-xlate.c
> @@ -444,6 +444,12 @@ const char *xlate_strerror(enum xlate_error error)
>           return "Invalid tunnel metadata";
>       case XLATE_UNSUPPORTED_PACKET_TYPE:
>           return "Unsupported packet type";
> +    case XLATE_CONGESTION_DROP:
> +        return "Congestion Drop";
> +    case XLATE_FORWARDING_DISABLED:
> +        return "Forwarding is disabled";
> +    case XLATE_MAX:
> +        break;
>       }
>       return "Unknown error";
>   }
> @@ -5943,6 +5949,13 @@ put_ct_label(const struct flow *flow, struct ofpbuf *odp_actions,
>   }
>   
>   static void
> +put_drop_action(struct ofpbuf *odp_actions, enum xlate_error error) {
> +    nl_msg_put_unspec(odp_actions, OVS_ACTION_ATTR_DROP,
> +                      &error, sizeof error);
> +
> +}
> +
> +static void
>   put_ct_helper(struct xlate_ctx *ctx,
>                 struct ofpbuf *odp_actions, struct ofpact_conntrack *ofc)
>   {
> @@ -7532,9 +7545,10 @@ xlate_actions(struct xlate_in *xin, struct xlate_out *xout)
>               compose_ipfix_action(&ctx, ODPP_NONE);
>           }
>           size_t sample_actions_len = ctx.odp_actions->size;
> +        bool ecn_drop = !tnl_process_ecn(flow);
>   
> -        if (tnl_process_ecn(flow)
> -            && (!in_port || may_receive(in_port, &ctx))) {
> +        if (!ecn_drop &&
> +                (!in_port || may_receive(in_port, &ctx))) {
>               const struct ofpact *ofpacts;
>               size_t ofpacts_len;
>   
> @@ -7573,6 +7587,8 @@ xlate_actions(struct xlate_in *xin, struct xlate_out *xout)
>               if (ctx.freezing) {
>                   finish_freezing(&ctx);
>               }
> +        } else if (ecn_drop) {
> +            ctx.error = XLATE_CONGESTION_DROP;
>           }
>   
>           /* Output only fully processed packets. */
> @@ -7672,6 +7688,20 @@ exit:
>               ofpbuf_clear(xin->odp_actions);
>           }
>       }
> +
> +
> +    /*
> +     * If we are going to install "drop" action, check whether
> +     * datapath supports explicit "drop"action. If datapath
> +     * supports explicit "drop"action then install the "drop"
> +     * action containing the drop reason.
> +     */
> +    if (xin->odp_actions && !xin->odp_actions->size &&
> +         ovs_explicit_drop_action_supported(ctx.xbridge->ofproto)) {
> +        put_drop_action(xin->odp_actions, ctx.error);
> +    }
> +
> +
>       return ctx.error;
>   }
>   
> diff --git a/ofproto/ofproto-dpif-xlate.h b/ofproto/ofproto-dpif-xlate.h
> index 5a51d7b..69b758b 100644
> --- a/ofproto/ofproto-dpif-xlate.h
> +++ b/ofproto/ofproto-dpif-xlate.h
> @@ -217,6 +217,9 @@ enum xlate_error {
>       XLATE_TOO_MANY_MPLS_LABELS,
>       XLATE_INVALID_TUNNEL_METADATA,
>       XLATE_UNSUPPORTED_PACKET_TYPE,
> +    XLATE_CONGESTION_DROP,
> +    XLATE_FORWARDING_DISABLED,
> +    XLATE_MAX,
>   };
>   
>   const char *xlate_strerror(enum xlate_error error);
> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> index db461ac..884ef52 100644
> --- a/ofproto/ofproto-dpif.c
> +++ b/ofproto/ofproto-dpif.c
> @@ -827,6 +827,11 @@ ovs_native_tunneling_is_on(struct ofproto_dpif *ofproto)
>           && atomic_count_get(&ofproto->backer->tnl_count);
>   }
>   
> +bool
> +ovs_explicit_drop_action_supported(struct ofproto_dpif *ofproto) {
> +    return ofproto->backer->rt_support.explicit_drop_action;
> +}
> +
>   /* Tests whether 'backer''s datapath supports recirculation.  Only newer
>    * datapaths support OVS_KEY_ATTR_RECIRC_ID in keys.  We need to disable some
>    * features on older datapaths that don't support this feature.
> @@ -1440,6 +1445,8 @@ check_support(struct dpif_backer *backer)
>       backer->rt_support.ct_clear = check_ct_clear(backer);
>       backer->rt_support.max_hash_alg = check_max_dp_hash_alg(backer);
>       backer->rt_support.check_pkt_len = check_check_pkt_len(backer);
> +    backer->rt_support.explicit_drop_action =
> +        dpif_supports_explicit_drop_action(backer->dpif);
>   
>       /* Flow fields. */
>       backer->rt_support.odp.ct_state = check_ct_state(backer);
> diff --git a/ofproto/ofproto-dpif.h b/ofproto/ofproto-dpif.h
> index cd5321e..f2f0f20 100644
> --- a/ofproto/ofproto-dpif.h
> +++ b/ofproto/ofproto-dpif.h
> @@ -195,7 +195,11 @@ struct group_dpif *group_dpif_lookup(struct ofproto_dpif *,
>       DPIF_SUPPORT_FIELD(size_t, max_hash_alg, "Max dp_hash algorithm")       \
>                                                                               \
>       /* True if the datapath supports OVS_ACTION_ATTR_CHECK_PKT_LEN. */   \
> -    DPIF_SUPPORT_FIELD(bool, check_pkt_len, "Check pkt length action")
> +    DPIF_SUPPORT_FIELD(bool, check_pkt_len, "Check pkt length action")     \
> +                                                                            \
> +    /* True if the datapath supports explicit drop action. */               \
> +    DPIF_SUPPORT_FIELD(bool, explicit_drop_action, "Explicit Drop action")
> +
>   
>   /* Stores the various features which the corresponding backer supports. */
>   struct dpif_backer_support {
> @@ -364,4 +368,6 @@ int ofproto_dpif_delete_internal_flow(struct ofproto_dpif *, struct match *,
>   
>   bool ovs_native_tunneling_is_on(struct ofproto_dpif *);
>   
> +bool ovs_explicit_drop_action_supported(struct ofproto_dpif *);
> +
>   #endif /* ofproto-dpif.h */
> diff --git a/tests/automake.mk b/tests/automake.mk
> index ea16532..dd67b57 100644
> --- a/tests/automake.mk
> +++ b/tests/automake.mk
> @@ -109,7 +109,8 @@ TESTSUITE_AT = \
>   	tests/ovn-controller-vtep.at \
>   	tests/mcast-snooping.at \
>   	tests/packet-type-aware.at \
> -	tests/nsh.at
> +	tests/nsh.at \
> +	tests/drop-stats.at
>   
>   EXTRA_DIST += $(FUZZ_REGRESSION_TESTS)
>   FUZZ_REGRESSION_TESTS = \
> diff --git a/tests/dpif-netdev.at b/tests/dpif-netdev.at
> index 039ee97..e6e0ed8 100644
> --- a/tests/dpif-netdev.at
> +++ b/tests/dpif-netdev.at
> @@ -349,6 +349,14 @@ meter:2 flow_count:1 packet_in_count:10 byte_in_count:600 duration:0.0s bands:
>   0: packet_count:5 byte_count:300
>   ])
>   
> +ovs-appctl time/warp 5000
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "datapath_drop_meter" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +14
> +])
> +
>   AT_CHECK([cat ovs-vswitchd.log | filter_flow_install | strip_xout_keep_actions], [0], [dnl
>   recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), actions:meter(0),7
>   recirc_id(0),in_port(2),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), actions:8
> diff --git a/tests/drop-stats.at b/tests/drop-stats.at
> new file mode 100644
> index 0000000..b94354d
> --- /dev/null
> +++ b/tests/drop-stats.at
> @@ -0,0 +1,211 @@
> +AT_BANNER([drop-stats])
> +
> +AT_SETUP([drop-stats - cli tests])
> +
> +OVS_VSWITCHD_START([dnl
> +    set bridge br0 datapath_type=dummy \
> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1])
> +
> +AT_DATA([flows.txt], [dnl
> +table=0,in_port=1,actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
> +actions ], [0], [dnl
> + in_port=1 actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1 1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e08006f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +    ovs-appctl netdev-dummy/receive p1 1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e08006f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +AT_CHECK([ovs-appctl dpctl/dump-flows | sed
> +'s/used:[[0-9]].[[0-9]]*s/used:0.0/' | sort], [0], [flow-dump from non-dpdk interfaces:
> +recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(fr
> +ag=no), packets:2, bytes:196, used:0.0, actions:drop
> +])
> +
> +sleep 1
> +
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_of_pipeline" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +3
> +])
> +
> +
> +OVS_VSWITCHD_STOP
> +AT_CLEANUP
> +
> +AT_SETUP([drop-stats - pipeline and recurssion drops])
> +
> +OVS_VSWITCHD_START([dnl
> +    set bridge br0 datapath_type=dummy \
> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1 -- \
> +    add-port br0 p2 -- set Interface p2 type=dummy ofport_request=2])
> +
> +AT_DATA([flows.txt], [dnl
> +table=0,in_port=1,actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
> +actions ], [0], [dnl
> + in_port=1 actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +sleep 1
> +
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_of_pipeline" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +AT_DATA([flows.txt], [dnl
> +table=0, in_port=1, actions=goto_table:1 table=1, in_port=1,
> +actions=goto_table:2 table=2, in_port=1, actions=resubmit(,1)
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
> +actions ], [0], [ignore])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_recursion_too_deep" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
> +AT_CLEANUP
> +
> +AT_SETUP([drop-stats - too many resubmit])
> +
> +OVS_VSWITCHD_START
> +add_of_ports br0 1
> +(for i in `seq 1 64`; do
> +     j=`expr $i + 1`
> +     echo "in_port=$i, actions=resubmit:$j, resubmit:$j, local"
> + done
> + echo "in_port=65, actions=local") > flows.txt
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt ], [0], [ignore])
> +
> +ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x1234)'
> +
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_too_many_resubmit" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
> +AT_CLEANUP
> +
> +
> +AT_SETUP([drop-stats - stack too deep]) OVS_VSWITCHD_START add_of_ports
> +br0 1 (for i in `seq 1 12`; do
> +     j=`expr $i + 1`
> +     echo "in_port=$i, actions=resubmit:$j, resubmit:$j, local"
> + done
> + push="push:NXM_NX_REG0[[]]"
> + echo "in_port=13,
> +actions=$push,$push,$push,$push,$push,$push,$push,$push") > flows
> +AT_CHECK([ovs-ofctl add-flows br0 flows])
> +
> +ovs-appctl netdev-dummy/receive p1 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x1234)'
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_stack_too_deep" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +OVS_VSWITCHD_STOP(["/resubmits yielded over 64 kB of stack/d"])
> +AT_CLEANUP
> +
> +AT_SETUP([drop-stats - too many mpls labels])
> +
> +OVS_VSWITCHD_START([dnl
> +    set bridge br0 datapath_type=dummy \
> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1 -- \
> +    add-port br0 p2 -- set Interface p2 type=dummy ofport_request=2])
> +
> +AT_DATA([flows.txt], [dnl
> +table=0, in_port=1, actions=push_mpls:0x8847, resubmit:3 table=0,
> +in_port=3, actions=push_mpls:0x8847, set_field:10->mpls_label,
> +set_field:15->mpls_label,  resubmit:4 table=0, in_port=4,
> +actions=push_mpls:0x8847, set_field:11->mpls_label, resubmit:5 table=0,
> +in_port=5, actions=push_mpls:0x8847, set_field:12->mpls_label,
> +resubmit:6 table=0, in_port=6, actions=push_mpls:0x8847,
> +set_field:13->mpls_label, output:2
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_too_many_mpls_labels" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
> +AT_CLEANUP
> +
> diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
> index 9b0231b..5e776a6 100644
> --- a/tests/ofproto-dpif.at
> +++ b/tests/ofproto-dpif.at
> @@ -9384,7 +9384,7 @@ recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x8100),vlan(vid=99,pcp=
>   # are wildcarded.
>   AT_CHECK([grep '\(modify\)\|\(flow_add\)' ovs-vswitchd.log | strip_ufid ], [0], [dnl
>   dpif_netdev|DBG|flow_add: recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x1234), actions:100
> -dpif|DBG|dummy@ovs-dummy: put[[modify]] skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234)
> +dpif|DBG|dummy@ovs-dummy: put[[modify]] skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234), actions:drop
>   dpif|DBG|dummy@ovs-dummy: put[[modify]] skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234), actions:100
>   dpif_netdev|DBG|flow_add: recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x8100),vlan(vid=99,pcp=7/0x0),encap(eth_type(0x1234)), actions:drop
>   ])
> diff --git a/tests/tunnel-push-pop.at b/tests/tunnel-push-pop.at
> index f717243..532c44e 100644
> --- a/tests/tunnel-push-pop.at
> +++ b/tests/tunnel-push-pop.at
> @@ -447,6 +447,28 @@ AT_CHECK([ovs-ofctl dump-ports int-br | grep 'port  7'], [0], [dnl
>     port  7: rx pkts=3, bytes=252, drop=?, errs=?, frame=?, over=?, crc=?
>   ])
>   
> +AT_CHECK([ovs-appctl netdev-dummy/receive p0 'aa55aa550000001b213cab6408004500007079464000402fba600101025c0101025820000800000001c845000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
> +
> +ovs-appctl time/warp 5000
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "datapath_drop_tunnel_pop_error" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +sleep 1
> +AT_CHECK([ovs-appctl netdev-dummy/receive p0 'aa55aa550000001b213cab6408004503007079464000402fba600101025c0101025820000800000001c845000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
> +
> +ovs-appctl time/warp 5000
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_congestion" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
>   dnl Check GREL3 only accepts non-fragmented packets?
>   AT_CHECK([ovs-appctl netdev-dummy/receive p0 'aa55aa550000001b213cab6408004500007e79464000402fba550101025c0101025820000800000001c8fe71d883724fbeb6f4e1494a080045000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
>   
> @@ -455,7 +477,7 @@ ovs-appctl time/warp 1000
>   
>   AT_CHECK([ovs-ofctl dump-ports int-br | grep 'port  [[37]]' | sort], [0], [dnl
>     port  3: rx pkts=3, bytes=294, drop=?, errs=?, frame=?, over=?, crc=?
> -  port  7: rx pkts=4, bytes=350, drop=?, errs=?, frame=?, over=?, crc=?
> +  port  7: rx pkts=5, bytes=434, drop=?, errs=?, frame=?, over=?, crc=?
>   ])
>   
>   dnl Check decapsulation of Geneve packet with options
> @@ -478,7 +500,7 @@ AT_CHECK([ovs-ofctl dump-ports int-br | grep 'port  5'], [0], [dnl
>     port  5: rx pkts=1, bytes=98, drop=?, errs=?, frame=?, over=?, crc=?
>   ])
>   AT_CHECK([ovs-appctl dpif/dump-flows int-br | grep 'in_port(6081)'], [0], [dnl
> -tunnel(tun_id=0x7b,src=1.1.2.92,dst=1.1.2.88,geneve({class=0xffff,type=0x80,len=4,0xa/0xf}{class=0xffff,type=0,len=4}),flags(-df-csum+key)),recirc_id(0),in_port(6081),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions:userspace(pid=0,controller(reason=1,dont_send=0,continuation=0,recirc_id=3,rule_cookie=0,controller_id=0,max_len=65535))
> +tunnel(tun_id=0x7b,src=1.1.2.92,dst=1.1.2.88,geneve({class=0xffff,type=0x80,len=4,0xa/0xf}{class=0xffff,type=0,len=4}),flags(-df-csum+key)),recirc_id(0),in_port(6081),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), packets:0, bytes:0, used:never, actions:userspace(pid=0,controller(reason=1,dont_send=0,continuation=0,recirc_id=2,rule_cookie=0,controller_id=0,max_len=65535))
>   ])
>   
>   ovs-appctl time/warp 10000
> @@ -510,7 +532,8 @@ AT_CHECK([ovs-appctl tnl/ports/show |sort], [0], [dnl
>   Listening ports:
>   ])
>   
> -OVS_VSWITCHD_STOP
> +OVS_VSWITCHD_STOP(["/dropping tunnel packet marked ECN CE but is not ECN capable/d
> +/ip packet has invalid checksum/d"])
>   AT_CLEANUP
>   
>   AT_SETUP([tunnel_push_pop - packet_out])
> diff --git a/tests/tunnel.at b/tests/tunnel.at
> index 035c54f..8b663e9 100644
> --- a/tests/tunnel.at
> +++ b/tests/tunnel.at
> @@ -102,9 +102,10 @@ Datapath actions: set(ipv4(tos=0x3/0x3)),2
>   
>   dnl Tunnel CE and encapsulated packet Non-ECT
>   AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 'tunnel(src=1.1.1.1,dst=2.2.2.2,tos=0x3,ttl=64,flags()),in_port(1),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0,ttl=64,frag=no),tcp(src=8,dst=9)'], [0], [stdout])
> -AT_CHECK([tail -2 stdout], [0],
> +AT_CHECK([tail -3 stdout], [0],
>     [Megaflow: recirc_id=0,eth,ip,tun_id=0,tun_src=1.1.1.1,tun_dst=2.2.2.2,tun_tos=3,tun_flags=-df-csum-key,in_port=1,nw_ecn=0,nw_frag=no
>   Datapath actions: drop
> +Translation failed (Congestion Drop), packet is dropped.
>   ])
>   OVS_VSWITCHD_STOP(["/dropping tunnel packet marked ECN CE but is not ECN capable/d"])
>   AT_CLEANUP
> @@ -193,6 +194,17 @@ AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 'in_port(2),eth(src=50:54:00:00:00:
>   AT_CHECK([tail -1 stdout], [0],
>     [Datapath actions: set(tunnel(tun_id=0x5,src=2.2.2.2,dst=1.1.1.1,ttl=64,flags(df|key))),set(skb_mark(0x2)),1
>   ])
> +
> +AT_CHECK([ovs-appctl netdev-dummy/receive p2 'aa55aa550001f8bc124434b6080045000054ba20000040018486010103580101037001004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
> +
> +sleep 2
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "datapath_drop_invalid_port" | cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
>   OVS_VSWITCHD_STOP
>   AT_CLEANUP
>

On 6/7/2019 2:31 PM, Gregory Rose wrote:
>
> On 6/6/2019 10:27 PM, Anju Thomas wrote:
>> Currently OVS maintains explicit packet drop/error counters only on 
>> port level.
>> Packets that are dropped as part of normal OpenFlow processing are 
>> counted in flow stats of “drop” flows or as table misses in table stats.
>> These can only be interpreted by controllers that know the semantics 
>> of the configured OpenFlow pipeline. Without that knowledge, it is 
>> impossible for an OVS user to obtain e.g. the total number of packets 
>> dropped due to OpenFlow rules.
>>
>> Furthermore, there are numerous other reasons for which packets can 
>> be dropped by OVS slow path that are not related to the OpenFlow 
>> pipeline.
>> The generated datapath flow entries include a drop action to avoid 
>> further expensive upcalls to the slow path, but subsequent packets 
>> dropped by the datapath are not accounted anywhere.
>>
>> Finally, the datapath itself drops packets in certain error situations.
>> Also, these drops are today not accounted for.
>>
>> This makes it difficult for OVS users to monitor packet drop in an 
>> OVS instance and to alert a management system in case of a unexpected 
>> increase of such drops. Also OVS trouble-shooters face difficulties 
>> in analysing packet drops.
>>
>> With this patch we implement following changes to address the issues 
>> mentioned above.
>>
>> 1. Identify and account all the silent packet drop scenarios
>>
>> 2. Display these drops in ovs-appctl coverage/show
>>
>> A detailed presentation on this was presented at OvS conference 2017 
>> and link for the corresponding presentation is available at:
>>
>> https://www.slideshare.net/LF_OpenvSwitch/lfovs17troubleshooting-the-data-plane-in-ovs-82280329 
>>
>>
>> Co-authored-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
>> Co-authored-by: Keshav Gupta <keshugupta1@gmail.com>
>> Signed-off-by: Anju Thomas <anju.thomas@ericsson.com>
>> Signed-off-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
>> Signed-off-by: Keshav Gupta <keshugupta1@gmail.com>
>
> Hi Anju et al,
>
> I am going to review and test this patch, however, I do have a request 
> just below...

I attempted to apply the patch and got the following errors:

Applying patch #1111568 using 'git am'
Description: [ovs-dev,v10] Improved Packet Drop Statistics in OVS
Applying: Improved Packet Drop Statistics in OVS
error: patch failed: tests/automake.mk:109
error: tests/automake.mk: patch does not apply
/home/gvrose/prj/ovs-experimental/.git/rebase-apply/patch:804: new blank 
line at EOF.
+
Patch failed at 0001 Improved Packet Drop Statistics in OVS
The copy of the patch that failed is found in:
    /home/gvrose/prj/ovs-experimental/.git/rebase-apply/patch
When you have resolved this problem, run "git am --resolved".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
'git am' failed with exit status 1

Please rebase to current master and I can give it another try.

Thanks,

- Greg


>
>> ---
>
> Here, below the three dash line just above, there should be an 
> accounting of all changes from version 1 of
> this patch set to version 10.  Something like this:
>
> v9 -> v10 Changed something due to review comments etc...
> v8 -> v9 Describe changes from v8 to v9 etc...
>
> I think it's essential to reviewers to understand the previous patches 
> and their evolution to the current patch.
>
> Thanks,
>
> - Greg
>
>> datapath/linux/compat/include/linux/openvswitch.h |   1 +
>>   lib/dpif-netdev.c                                 |  46 ++++-
>>   lib/dpif.c                                        |   7 +
>>   lib/dpif.h                                        |   4 +
>>   lib/odp-execute.c                                 |  78 ++++++++
>>   lib/odp-util.c                                    |   9 +
>>   ofproto/ofproto-dpif-ipfix.c                      |   1 +
>>   ofproto/ofproto-dpif-sflow.c                      |   1 +
>>   ofproto/ofproto-dpif-xlate.c                      |  34 +++-
>>   ofproto/ofproto-dpif-xlate.h                      |   3 +
>>   ofproto/ofproto-dpif.c                            |   7 +
>>   ofproto/ofproto-dpif.h                            |   8 +-
>>   tests/automake.mk                                 |   3 +-
>>   tests/dpif-netdev.at                              |   8 +
>>   tests/drop-stats.at                               | 211 
>> ++++++++++++++++++++++
>>   tests/ofproto-dpif.at                             |   2 +-
>>   tests/tunnel-push-pop.at                          |  29 ++-
>>   tests/tunnel.at                                   |  14 +-
>>   18 files changed, 455 insertions(+), 11 deletions(-)
>>   create mode 100644 tests/drop-stats.at
>>
>> diff --git a/datapath/linux/compat/include/linux/openvswitch.h 
>> b/datapath/linux/compat/include/linux/openvswitch.h
>> index 65a003a..2de702e 100644
>> --- a/datapath/linux/compat/include/linux/openvswitch.h
>> +++ b/datapath/linux/compat/include/linux/openvswitch.h
>> @@ -985,6 +985,7 @@ enum ovs_action_attr {
>>       OVS_ACTION_ATTR_METER,        /* u32 meter number. */
>>       OVS_ACTION_ATTR_CLONE,        /* Nested OVS_CLONE_ATTR_*. */
>>       OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested 
>> OVS_CHECK_PKT_LEN_ATTR_*. */
>> +    OVS_ACTION_ATTR_DROP,
>>     #ifndef __KERNEL__
>>       OVS_ACTION_ATTR_TUNNEL_PUSH,   /* struct ovs_action_push_tnl*/
>> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
>> index 5a6f2ab..ec72403 100644
>> --- a/lib/dpif-netdev.c
>> +++ b/lib/dpif-netdev.c
>> @@ -101,6 +101,17 @@ enum { MAX_METERS = 65536 };    /* Maximum 
>> number of meters. */
>>   enum { MAX_BANDS = 8 };         /* Maximum number of bands / meter. */
>>   enum { N_METER_LOCKS = 64 };    /* Maximum number of meters. */
>>   +COVERAGE_DEFINE(datapath_drop_meter);
>> +COVERAGE_DEFINE(datapath_drop_upcall_error);
>> +COVERAGE_DEFINE(datapath_drop_lock_error);
>> +COVERAGE_DEFINE(datapath_drop_userspace_action_error);
>> +COVERAGE_DEFINE(datapath_drop_tunnel_push_error);
>> +COVERAGE_DEFINE(datapath_drop_tunnel_pop_error);
>> +COVERAGE_DEFINE(datapath_drop_recirc_error);
>> +COVERAGE_DEFINE(datapath_drop_invalid_port);
>> +COVERAGE_DEFINE(datapath_drop_invalid_tnl_port);
>> +COVERAGE_DEFINE(datapath_drop_rx_invalid_packet);
>> +
>>   /* Protects against changes to 'dp_netdevs'. */
>>   static struct ovs_mutex dp_netdev_mutex = OVS_MUTEX_INITIALIZER;
>>   @@ -5646,7 +5657,7 @@ dp_netdev_run_meter(struct dp_netdev *dp, 
>> struct dp_packet_batch *packets_,
>>               band = &meter->bands[exceeded_band[j]];
>>               band->packet_count += 1;
>>               band->byte_count += dp_packet_size(packet);
>> -
>> +            COVERAGE_INC(datapath_drop_meter);
>>               dp_packet_delete(packet);
>>           } else {
>>               /* Meter accepts packet. */
>> @@ -6402,6 +6413,7 @@ dfc_processing(struct dp_netdev_pmd_thread *pmd,
>>             if (OVS_UNLIKELY(dp_packet_size(packet) < ETH_HEADER_LEN)) {
>>               dp_packet_delete(packet);
>> +            COVERAGE_INC(datapath_drop_rx_invalid_packet);
>>               continue;
>>           }
>>   @@ -6521,6 +6533,7 @@ handle_packet_upcall(struct 
>> dp_netdev_pmd_thread *pmd,
>>                                put_actions);
>>       if (OVS_UNLIKELY(error && error != ENOSPC)) {
>>           dp_packet_delete(packet);
>> +        COVERAGE_INC(datapath_drop_upcall_error);
>>           return error;
>>       }
>>   @@ -6651,6 +6664,7 @@ fast_path_processing(struct 
>> dp_netdev_pmd_thread *pmd,
>>           DP_PACKET_BATCH_FOR_EACH (i, packet, packets_) {
>>               if (OVS_UNLIKELY(!rules[i])) {
>>                   dp_packet_delete(packet);
>> +                COVERAGE_INC(datapath_drop_lock_error);
>>                   upcall_fail_cnt++;
>>               }
>>           }
>> @@ -6920,6 +6934,7 @@ dp_execute_userspace_action(struct 
>> dp_netdev_pmd_thread *pmd,
>>                                     actions->data, actions->size);
>>       } else if (should_steal) {
>>           dp_packet_delete(packet);
>> +        COVERAGE_INC(datapath_drop_userspace_action_error);
>>       }
>>   }
>>   @@ -6934,6 +6949,7 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>       struct dp_netdev *dp = pmd->dp;
>>       int type = nl_attr_type(a);
>>       struct tx_port *p;
>> +    uint32_t packet_count, packet_dropped;
>>         switch ((enum ovs_action_attr)type) {
>>       case OVS_ACTION_ATTR_OUTPUT:
>> @@ -6975,6 +6991,9 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>                   dp_packet_batch_add(&p->output_pkts, packet);
>>               }
>>               return;
>> +        } else {
>> +            COVERAGE_ADD(datapath_drop_invalid_port,
>> +                            dp_packet_batch_size(packets_));
>>           }
>>           break;
>>   @@ -6984,10 +7003,16 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>                * the ownership of these packets. Thus, we can avoid 
>> performing
>>                * the action, because the caller will not use the 
>> result anyway.
>>                * Just break to free the batch. */
>> +            COVERAGE_ADD(datapath_drop_tunnel_push_error,
>> +                            dp_packet_batch_size(packets_));
>>               break;
>>           }
>>           dp_packet_batch_apply_cutlen(packets_);
>> -        push_tnl_action(pmd, a, packets_);
>> +        packet_count = dp_packet_batch_size(packets_);
>> +        if (push_tnl_action(pmd, a, packets_)) {
>> +            COVERAGE_ADD(datapath_drop_tunnel_push_error,
>> +                            packet_count);
>> +        }
>>           return;
>>         case OVS_ACTION_ATTR_TUNNEL_POP:
>> @@ -7007,7 +7032,13 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>                     dp_packet_batch_apply_cutlen(packets_);
>>   +                packet_count = dp_packet_batch_size(packets_);
>>                   netdev_pop_header(p->port->netdev, packets_);
>> +                packet_dropped = packet_count - packets_->count;
>> +                if (packet_dropped) {
>> + COVERAGE_ADD(datapath_drop_tunnel_pop_error,
>> +                                     packet_dropped);
>> +                }
>>                   if (dp_packet_batch_is_empty(packets_)) {
>>                       return;
>>                   }
>> @@ -7022,6 +7053,11 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>                   (*depth)--;
>>                   return;
>>               }
>> +            COVERAGE_ADD(datapath_drop_invalid_tnl_port,
>> +                            dp_packet_batch_size(packets_));
>> +        } else {
>> +            COVERAGE_ADD(datapath_drop_recirc_error,
>> +                            dp_packet_batch_size(packets_));
>>           }
>>           break;
>>   @@ -7066,6 +7102,9 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>                 return;
>>           }
>> +        COVERAGE_ADD(datapath_drop_lock_error,
>> +                        dp_packet_batch_size(packets_));
>> +
>>           break;
>>         case OVS_ACTION_ATTR_RECIRC:
>> @@ -7089,6 +7128,8 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>               return;
>>           }
>>   +        COVERAGE_ADD(datapath_drop_recirc_error,
>> +                        dp_packet_batch_size(packets_));
>>           VLOG_WARN("Packet dropped. Max recirculation depth 
>> exceeded.");
>>           break;
>>   @@ -7242,6 +7283,7 @@ dp_execute_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>       case OVS_ACTION_ATTR_POP_NSH:
>>       case OVS_ACTION_ATTR_CT_CLEAR:
>>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>> +    case OVS_ACTION_ATTR_DROP:
>>       case __OVS_ACTION_ATTR_MAX:
>>           OVS_NOT_REACHED();
>>       }
>> diff --git a/lib/dpif.c b/lib/dpif.c
>> index a18fb1b..112e9d1 100644
>> --- a/lib/dpif.c
>> +++ b/lib/dpif.c
>> @@ -1267,6 +1267,7 @@ dpif_execute_helper_cb(void *aux_, struct 
>> dp_packet_batch *packets_,
>>       case OVS_ACTION_ATTR_CT_CLEAR:
>>       case OVS_ACTION_ATTR_UNSPEC:
>>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>> +    case OVS_ACTION_ATTR_DROP:
>>       case __OVS_ACTION_ATTR_MAX:
>>           OVS_NOT_REACHED();
>>       }
>> @@ -1872,6 +1873,12 @@ dpif_supports_tnl_push_pop(const struct dpif 
>> *dpif)
>>       return dpif_is_netdev(dpif);
>>   }
>>   +bool
>> +dpif_supports_explicit_drop_action(const struct dpif *dpif) {
>> +    return dpif_is_netdev(dpif);
>> +}
>> +
>> +
>>   /* Meters */
>>   void
>>   dpif_meter_get_features(const struct dpif *dpif,
>> diff --git a/lib/dpif.h b/lib/dpif.h
>> index 475d5a6..4b9a434 100644
>> --- a/lib/dpif.h
>> +++ b/lib/dpif.h
>> @@ -888,6 +888,10 @@ int dpif_get_pmds_for_port(const struct dpif * 
>> dpif, odp_port_t port_no,
>>     char *dpif_get_dp_version(const struct dpif *);
>>   bool dpif_supports_tnl_push_pop(const struct dpif *);
>> +bool dpif_supports_explicit_drop_action(const struct dpif *);
>> +int dpif_show_drop_stats_support(struct dpif *dpif, bool detail,
>> +                          struct ds *reply);
>> +
>>     /* Log functions. */
>>   struct vlog_module;
>> diff --git a/lib/odp-execute.c b/lib/odp-execute.c
>> index 563ad1d..e243e89 100644
>> --- a/lib/odp-execute.c
>> +++ b/lib/odp-execute.c
>> @@ -25,6 +25,7 @@
>>   #include <stdlib.h>
>>   #include <string.h>
>>   +#include "coverage.h"
>>   #include "dp-packet.h"
>>   #include "dpif.h"
>>   #include "netlink.h"
>> @@ -36,6 +37,72 @@
>>   #include "util.h"
>>   #include "csum.h"
>>   #include "conntrack.h"
>> +#include "ofproto/ofproto-dpif-xlate.h"
>> +#include "openvswitch/vlog.h"
>> +
>> +VLOG_DEFINE_THIS_MODULE(odp_execute)
>> +COVERAGE_DEFINE(datapath_drop_sample_error);
>> +COVERAGE_DEFINE(datapath_drop_nsh_decap_error);
>> +COVERAGE_DEFINE(drop_action_of_pipeline);
>> +COVERAGE_DEFINE(drop_action_bridge_not_found);
>> +COVERAGE_DEFINE(drop_action_recursion_too_deep);
>> +COVERAGE_DEFINE(drop_action_too_many_resubmit);
>> +COVERAGE_DEFINE(drop_action_stack_too_deep);
>> +COVERAGE_DEFINE(drop_action_no_recirculation_context);
>> +COVERAGE_DEFINE(drop_action_recirculation_conflict);
>> +COVERAGE_DEFINE(drop_action_too_many_mpls_labels);
>> +COVERAGE_DEFINE(drop_action_invalid_tunnel_metadata);
>> +COVERAGE_DEFINE(drop_action_unsupported_packet_type);
>> +COVERAGE_DEFINE(drop_action_congestion);
>> +COVERAGE_DEFINE(drop_action_forwarding_disabled);
>> +
>> +static void
>> +dp_update_drop_action_counter(enum xlate_error drop_reason,
>> +                                 int delta) {
>> +   static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
>> +
>> +   switch (drop_reason) {
>> +   case XLATE_OK:
>> +        COVERAGE_ADD(drop_action_of_pipeline, delta);
>> +        break;
>> +   case XLATE_BRIDGE_NOT_FOUND:
>> +        COVERAGE_ADD(drop_action_bridge_not_found, delta);
>> +        break;
>> +   case XLATE_RECURSION_TOO_DEEP:
>> +        COVERAGE_ADD(drop_action_recursion_too_deep, delta);
>> +        break;
>> +   case XLATE_TOO_MANY_RESUBMITS:
>> +        COVERAGE_ADD(drop_action_too_many_resubmit, delta);
>> +        break;
>> +   case XLATE_STACK_TOO_DEEP:
>> +        COVERAGE_ADD(drop_action_stack_too_deep, delta);
>> +        break;
>> +   case XLATE_NO_RECIRCULATION_CONTEXT:
>> +        COVERAGE_ADD(drop_action_no_recirculation_context, delta);
>> +        break;
>> +   case XLATE_RECIRCULATION_CONFLICT:
>> +        COVERAGE_ADD(drop_action_recirculation_conflict, delta);
>> +        break;
>> +   case XLATE_TOO_MANY_MPLS_LABELS:
>> +        COVERAGE_ADD(drop_action_too_many_mpls_labels, delta);
>> +        break;
>> +   case XLATE_INVALID_TUNNEL_METADATA:
>> +        COVERAGE_ADD(drop_action_invalid_tunnel_metadata, delta);
>> +        break;
>> +   case XLATE_UNSUPPORTED_PACKET_TYPE:
>> +        COVERAGE_ADD(drop_action_unsupported_packet_type, delta);
>> +        break;
>> +   case XLATE_CONGESTION_DROP:
>> +        COVERAGE_ADD(drop_action_congestion, delta);
>> +        break;
>> +   case XLATE_FORWARDING_DISABLED:
>> +        COVERAGE_ADD(drop_action_forwarding_disabled, delta);
>> +        break;
>> +   case XLATE_MAX:
>> +   default:
>> +        VLOG_ERR_RL(&rl, "Invalid Drop reason type:%d", drop_reason);
>> +   }
>> +}
>>     /* Masked copy of an ethernet address. 'src' is already properly 
>> masked. */
>>   static void
>> @@ -621,6 +688,7 @@ odp_execute_sample(void *dp, struct dp_packet 
>> *packet, bool steal,
>>           case OVS_SAMPLE_ATTR_PROBABILITY:
>>               if (random_uint32() >= nl_attr_get_u32(a)) {
>>                   if (steal) {
>> +                    COVERAGE_ADD(datapath_drop_sample_error, 1);
>>                       dp_packet_delete(packet);
>>                   }
>>                   return;
>> @@ -749,6 +817,7 @@ requires_datapath_assistance(const struct nlattr *a)
>>       case OVS_ACTION_ATTR_POP_NSH:
>>       case OVS_ACTION_ATTR_CT_CLEAR:
>>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>> +    case OVS_ACTION_ATTR_DROP:
>>           return false;
>>         case OVS_ACTION_ATTR_UNSPEC:
>> @@ -965,6 +1034,7 @@ odp_execute_actions(void *dp, struct 
>> dp_packet_batch *batch, bool steal,
>>                   if (pop_nsh(packet)) {
>>                       dp_packet_batch_refill(batch, packet, i);
>>                   } else {
>> + COVERAGE_INC(datapath_drop_nsh_decap_error);
>>                       dp_packet_delete(packet);
>>                   }
>>               }
>> @@ -989,6 +1059,14 @@ odp_execute_actions(void *dp, struct 
>> dp_packet_batch *batch, bool steal,
>>               }
>>               break;
>>   +        case OVS_ACTION_ATTR_DROP:{
>> +            const enum xlate_error *drop_reason = nl_attr_get(a);
>> +            if (*drop_reason < XLATE_MAX) {
>> +                 dp_update_drop_action_counter(*drop_reason, 
>> batch->count);
>> +            }
>> +            dp_packet_delete_batch(batch, steal);
>> +            return;
>> +        }
>>           case OVS_ACTION_ATTR_OUTPUT:
>>           case OVS_ACTION_ATTR_TUNNEL_PUSH:
>>           case OVS_ACTION_ATTR_TUNNEL_POP:
>> diff --git a/lib/odp-util.c b/lib/odp-util.c
>> index 3a28877..0dbb6d9 100644
>> --- a/lib/odp-util.c
>> +++ b/lib/odp-util.c
>> @@ -44,6 +44,7 @@
>>   #include "openvswitch/vlog.h"
>>   #include "openvswitch/match.h"
>>   #include "odp-netlink-macros.h"
>> +#include "ofproto/ofproto-dpif-xlate.h"
>>     VLOG_DEFINE_THIS_MODULE(odp_util);
>>   @@ -140,6 +141,7 @@ odp_action_len(uint16_t type)
>>       case OVS_ACTION_ATTR_PUSH_NSH: return ATTR_LEN_VARIABLE;
>>       case OVS_ACTION_ATTR_POP_NSH: return 0;
>>       case OVS_ACTION_ATTR_CHECK_PKT_LEN: return ATTR_LEN_VARIABLE;
>> +    case OVS_ACTION_ATTR_DROP: return sizeof(enum xlate_error);
>>         case OVS_ACTION_ATTR_UNSPEC:
>>       case __OVS_ACTION_ATTR_MAX:
>> @@ -1230,6 +1232,9 @@ format_odp_action(struct ds *ds, const struct 
>> nlattr *a,
>>       case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>>           format_odp_check_pkt_len_action(ds, a, portno_names);
>>           break;
>> +    case OVS_ACTION_ATTR_DROP:
>> +        ds_put_cstr(ds, "drop");
>> +        break;
>>       case OVS_ACTION_ATTR_UNSPEC:
>>       case __OVS_ACTION_ATTR_MAX:
>>       default:
>> @@ -2547,8 +2552,12 @@ odp_actions_from_string(const char *s, const 
>> struct simap *port_names,
>>                           struct ofpbuf *actions)
>>   {
>>       size_t old_size;
>> +    enum xlate_error drop_action;
>>         if (!strcasecmp(s, "drop")) {
>> +        drop_action = XLATE_OK;
>> +        nl_msg_put_unspec(actions, OVS_ACTION_ATTR_DROP,
>> +                          &drop_action, sizeof drop_action);
>>           return 0;
>>       }
>>   diff --git a/ofproto/ofproto-dpif-ipfix.c 
>> b/ofproto/ofproto-dpif-ipfix.c
>> index b8bd1b8..b413768 100644
>> --- a/ofproto/ofproto-dpif-ipfix.c
>> +++ b/ofproto/ofproto-dpif-ipfix.c
>> @@ -3016,6 +3016,7 @@ dpif_ipfix_read_actions(const struct flow *flow,
>>           case OVS_ACTION_ATTR_POP_NSH:
>>           case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>>           case OVS_ACTION_ATTR_UNSPEC:
>> +        case OVS_ACTION_ATTR_DROP:
>>           case __OVS_ACTION_ATTR_MAX:
>>           default:
>>               break;
>> diff --git a/ofproto/ofproto-dpif-sflow.c b/ofproto/ofproto-dpif-sflow.c
>> index 03bd763..387e9b5 100644
>> --- a/ofproto/ofproto-dpif-sflow.c
>> +++ b/ofproto/ofproto-dpif-sflow.c
>> @@ -1224,6 +1224,7 @@ dpif_sflow_read_actions(const struct flow *flow,
>>           case OVS_ACTION_ATTR_POP_NSH:
>>           case OVS_ACTION_ATTR_UNSPEC:
>>           case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>> +        case OVS_ACTION_ATTR_DROP:
>>           case __OVS_ACTION_ATTR_MAX:
>>           default:
>>               break;
>> diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
>> index 5cee37f..1a9c6fe 100644
>> --- a/ofproto/ofproto-dpif-xlate.c
>> +++ b/ofproto/ofproto-dpif-xlate.c
>> @@ -444,6 +444,12 @@ const char *xlate_strerror(enum xlate_error error)
>>           return "Invalid tunnel metadata";
>>       case XLATE_UNSUPPORTED_PACKET_TYPE:
>>           return "Unsupported packet type";
>> +    case XLATE_CONGESTION_DROP:
>> +        return "Congestion Drop";
>> +    case XLATE_FORWARDING_DISABLED:
>> +        return "Forwarding is disabled";
>> +    case XLATE_MAX:
>> +        break;
>>       }
>>       return "Unknown error";
>>   }
>> @@ -5943,6 +5949,13 @@ put_ct_label(const struct flow *flow, struct 
>> ofpbuf *odp_actions,
>>   }
>>     static void
>> +put_drop_action(struct ofpbuf *odp_actions, enum xlate_error error) {
>> +    nl_msg_put_unspec(odp_actions, OVS_ACTION_ATTR_DROP,
>> +                      &error, sizeof error);
>> +
>> +}
>> +
>> +static void
>>   put_ct_helper(struct xlate_ctx *ctx,
>>                 struct ofpbuf *odp_actions, struct ofpact_conntrack 
>> *ofc)
>>   {
>> @@ -7532,9 +7545,10 @@ xlate_actions(struct xlate_in *xin, struct 
>> xlate_out *xout)
>>               compose_ipfix_action(&ctx, ODPP_NONE);
>>           }
>>           size_t sample_actions_len = ctx.odp_actions->size;
>> +        bool ecn_drop = !tnl_process_ecn(flow);
>>   -        if (tnl_process_ecn(flow)
>> -            && (!in_port || may_receive(in_port, &ctx))) {
>> +        if (!ecn_drop &&
>> +                (!in_port || may_receive(in_port, &ctx))) {
>>               const struct ofpact *ofpacts;
>>               size_t ofpacts_len;
>>   @@ -7573,6 +7587,8 @@ xlate_actions(struct xlate_in *xin, struct 
>> xlate_out *xout)
>>               if (ctx.freezing) {
>>                   finish_freezing(&ctx);
>>               }
>> +        } else if (ecn_drop) {
>> +            ctx.error = XLATE_CONGESTION_DROP;
>>           }
>>             /* Output only fully processed packets. */
>> @@ -7672,6 +7688,20 @@ exit:
>>               ofpbuf_clear(xin->odp_actions);
>>           }
>>       }
>> +
>> +
>> +    /*
>> +     * If we are going to install "drop" action, check whether
>> +     * datapath supports explicit "drop"action. If datapath
>> +     * supports explicit "drop"action then install the "drop"
>> +     * action containing the drop reason.
>> +     */
>> +    if (xin->odp_actions && !xin->odp_actions->size &&
>> + ovs_explicit_drop_action_supported(ctx.xbridge->ofproto)) {
>> +        put_drop_action(xin->odp_actions, ctx.error);
>> +    }
>> +
>> +
>>       return ctx.error;
>>   }
>>   diff --git a/ofproto/ofproto-dpif-xlate.h 
>> b/ofproto/ofproto-dpif-xlate.h
>> index 5a51d7b..69b758b 100644
>> --- a/ofproto/ofproto-dpif-xlate.h
>> +++ b/ofproto/ofproto-dpif-xlate.h
>> @@ -217,6 +217,9 @@ enum xlate_error {
>>       XLATE_TOO_MANY_MPLS_LABELS,
>>       XLATE_INVALID_TUNNEL_METADATA,
>>       XLATE_UNSUPPORTED_PACKET_TYPE,
>> +    XLATE_CONGESTION_DROP,
>> +    XLATE_FORWARDING_DISABLED,
>> +    XLATE_MAX,
>>   };
>>     const char *xlate_strerror(enum xlate_error error);
>> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
>> index db461ac..884ef52 100644
>> --- a/ofproto/ofproto-dpif.c
>> +++ b/ofproto/ofproto-dpif.c
>> @@ -827,6 +827,11 @@ ovs_native_tunneling_is_on(struct ofproto_dpif 
>> *ofproto)
>>           && atomic_count_get(&ofproto->backer->tnl_count);
>>   }
>>   +bool
>> +ovs_explicit_drop_action_supported(struct ofproto_dpif *ofproto) {
>> +    return ofproto->backer->rt_support.explicit_drop_action;
>> +}
>> +
>>   /* Tests whether 'backer''s datapath supports recirculation. Only 
>> newer
>>    * datapaths support OVS_KEY_ATTR_RECIRC_ID in keys.  We need to 
>> disable some
>>    * features on older datapaths that don't support this feature.
>> @@ -1440,6 +1445,8 @@ check_support(struct dpif_backer *backer)
>>       backer->rt_support.ct_clear = check_ct_clear(backer);
>>       backer->rt_support.max_hash_alg = check_max_dp_hash_alg(backer);
>>       backer->rt_support.check_pkt_len = check_check_pkt_len(backer);
>> +    backer->rt_support.explicit_drop_action =
>> +        dpif_supports_explicit_drop_action(backer->dpif);
>>         /* Flow fields. */
>>       backer->rt_support.odp.ct_state = check_ct_state(backer);
>> diff --git a/ofproto/ofproto-dpif.h b/ofproto/ofproto-dpif.h
>> index cd5321e..f2f0f20 100644
>> --- a/ofproto/ofproto-dpif.h
>> +++ b/ofproto/ofproto-dpif.h
>> @@ -195,7 +195,11 @@ struct group_dpif *group_dpif_lookup(struct 
>> ofproto_dpif *,
>>       DPIF_SUPPORT_FIELD(size_t, max_hash_alg, "Max dp_hash 
>> algorithm")       \
>> \
>>       /* True if the datapath supports OVS_ACTION_ATTR_CHECK_PKT_LEN. 
>> */   \
>> -    DPIF_SUPPORT_FIELD(bool, check_pkt_len, "Check pkt length action")
>> +    DPIF_SUPPORT_FIELD(bool, check_pkt_len, "Check pkt length 
>> action")     \
>> + \
>> +    /* True if the datapath supports explicit drop action. 
>> */               \
>> +    DPIF_SUPPORT_FIELD(bool, explicit_drop_action, "Explicit Drop 
>> action")
>> +
>>     /* Stores the various features which the corresponding backer 
>> supports. */
>>   struct dpif_backer_support {
>> @@ -364,4 +368,6 @@ int ofproto_dpif_delete_internal_flow(struct 
>> ofproto_dpif *, struct match *,
>>     bool ovs_native_tunneling_is_on(struct ofproto_dpif *);
>>   +bool ovs_explicit_drop_action_supported(struct ofproto_dpif *);
>> +
>>   #endif /* ofproto-dpif.h */
>> diff --git a/tests/automake.mk b/tests/automake.mk
>> index ea16532..dd67b57 100644
>> --- a/tests/automake.mk
>> +++ b/tests/automake.mk
>> @@ -109,7 +109,8 @@ TESTSUITE_AT = \
>>       tests/ovn-controller-vtep.at \
>>       tests/mcast-snooping.at \
>>       tests/packet-type-aware.at \
>> -    tests/nsh.at
>> +    tests/nsh.at \
>> +    tests/drop-stats.at
>>     EXTRA_DIST += $(FUZZ_REGRESSION_TESTS)
>>   FUZZ_REGRESSION_TESTS = \
>> diff --git a/tests/dpif-netdev.at b/tests/dpif-netdev.at
>> index 039ee97..e6e0ed8 100644
>> --- a/tests/dpif-netdev.at
>> +++ b/tests/dpif-netdev.at
>> @@ -349,6 +349,14 @@ meter:2 flow_count:1 packet_in_count:10 
>> byte_in_count:600 duration:0.0s bands:
>>   0: packet_count:5 byte_count:300
>>   ])
>>   +ovs-appctl time/warp 5000
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "datapath_drop_meter" | cut -d':' 
>> -f2|sed 's/ //'
>> +], [0], [dnl
>> +14
>> +])
>> +
>>   AT_CHECK([cat ovs-vswitchd.log | filter_flow_install | 
>> strip_xout_keep_actions], [0], [dnl
>> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
>> actions:meter(0),7
>> recirc_id(0),in_port(2),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
>> actions:8
>> diff --git a/tests/drop-stats.at b/tests/drop-stats.at
>> new file mode 100644
>> index 0000000..b94354d
>> --- /dev/null
>> +++ b/tests/drop-stats.at
>> @@ -0,0 +1,211 @@
>> +AT_BANNER([drop-stats])
>> +
>> +AT_SETUP([drop-stats - cli tests])
>> +
>> +OVS_VSWITCHD_START([dnl
>> +    set bridge br0 datapath_type=dummy \
>> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
>> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1])
>> +
>> +AT_DATA([flows.txt], [dnl
>> +table=0,in_port=1,actions=drop
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-ofctl del-flows br0
>> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
>> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
>> +actions ], [0], [dnl
>> + in_port=1 actions=drop
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-appctl netdev-dummy/receive p1 
>> 1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e08006f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
>> +    ovs-appctl netdev-dummy/receive p1 
>> 1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e08006f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
>> +    ovs-appctl netdev-dummy/receive p1
>> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
>> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
>> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
>> +], [0], [ignore])
>> +
>> +AT_CHECK([ovs-appctl dpctl/dump-flows | sed
>> +'s/used:[[0-9]].[[0-9]]*s/used:0.0/' | sort], [0], [flow-dump from 
>> non-dpdk interfaces:
>> +recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(fr
>> +ag=no), packets:2, bytes:196, used:0.0, actions:drop
>> +])
>> +
>> +sleep 1
>> +
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_of_pipeline" | cut 
>> -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +3
>> +])
>> +
>> +
>> +OVS_VSWITCHD_STOP
>> +AT_CLEANUP
>> +
>> +AT_SETUP([drop-stats - pipeline and recurssion drops])
>> +
>> +OVS_VSWITCHD_START([dnl
>> +    set bridge br0 datapath_type=dummy \
>> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
>> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1 
>> -- \
>> +    add-port br0 p2 -- set Interface p2 type=dummy ofport_request=2])
>> +
>> +AT_DATA([flows.txt], [dnl
>> +table=0,in_port=1,actions=drop
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-ofctl del-flows br0
>> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
>> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
>> +actions ], [0], [dnl
>> + in_port=1 actions=drop
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-appctl netdev-dummy/receive p1
>> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
>> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
>> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
>> +], [0], [ignore])
>> +
>> +sleep 1
>> +
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_of_pipeline" | cut 
>> -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +
>> +AT_DATA([flows.txt], [dnl
>> +table=0, in_port=1, actions=goto_table:1 table=1, in_port=1,
>> +actions=goto_table:2 table=2, in_port=1, actions=resubmit(,1)
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-ofctl del-flows br0
>> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
>> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
>> +actions ], [0], [ignore])
>> +
>> +AT_CHECK([
>> +    ovs-appctl netdev-dummy/receive p1
>> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
>> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
>> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
>> +], [0], [ignore])
>> +
>> +sleep 1
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_recursion_too_deep" | 
>> cut -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +
>> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
>> +AT_CLEANUP
>> +
>> +AT_SETUP([drop-stats - too many resubmit])
>> +
>> +OVS_VSWITCHD_START
>> +add_of_ports br0 1
>> +(for i in `seq 1 64`; do
>> +     j=`expr $i + 1`
>> +     echo "in_port=$i, actions=resubmit:$j, resubmit:$j, local"
>> + done
>> + echo "in_port=65, actions=local") > flows.txt
>> +
>> +AT_CHECK([
>> +    ovs-ofctl del-flows br0
>> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt ], [0], [ignore])
>> +
>> +ovs-appctl netdev-dummy/receive p1 
>> 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x1234)'
>> +
>> +
>> +sleep 1
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_too_many_resubmit" | 
>> cut -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
>> +AT_CLEANUP
>> +
>> +
>> +AT_SETUP([drop-stats - stack too deep]) OVS_VSWITCHD_START add_of_ports
>> +br0 1 (for i in `seq 1 12`; do
>> +     j=`expr $i + 1`
>> +     echo "in_port=$i, actions=resubmit:$j, resubmit:$j, local"
>> + done
>> + push="push:NXM_NX_REG0[[]]"
>> + echo "in_port=13,
>> +actions=$push,$push,$push,$push,$push,$push,$push,$push") > flows
>> +AT_CHECK([ovs-ofctl add-flows br0 flows])
>> +
>> +ovs-appctl netdev-dummy/receive p1 
>> 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x1234)'
>> +
>> +sleep 1
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_stack_too_deep" | cut 
>> -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +
>> +OVS_VSWITCHD_STOP(["/resubmits yielded over 64 kB of stack/d"])
>> +AT_CLEANUP
>> +
>> +AT_SETUP([drop-stats - too many mpls labels])
>> +
>> +OVS_VSWITCHD_START([dnl
>> +    set bridge br0 datapath_type=dummy \
>> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
>> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1 
>> -- \
>> +    add-port br0 p2 -- set Interface p2 type=dummy ofport_request=2])
>> +
>> +AT_DATA([flows.txt], [dnl
>> +table=0, in_port=1, actions=push_mpls:0x8847, resubmit:3 table=0,
>> +in_port=3, actions=push_mpls:0x8847, set_field:10->mpls_label,
>> +set_field:15->mpls_label,  resubmit:4 table=0, in_port=4,
>> +actions=push_mpls:0x8847, set_field:11->mpls_label, resubmit:5 table=0,
>> +in_port=5, actions=push_mpls:0x8847, set_field:12->mpls_label,
>> +resubmit:6 table=0, in_port=6, actions=push_mpls:0x8847,
>> +set_field:13->mpls_label, output:2
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-ofctl del-flows br0
>> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
>> +])
>> +
>> +AT_CHECK([
>> +    ovs-appctl netdev-dummy/receive p1
>> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
>> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
>> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
>> +], [0], [ignore])
>> +
>> +sleep 1
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_too_many_mpls_labels" | 
>> cut -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +
>> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
>> +AT_CLEANUP
>> +
>> diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
>> index 9b0231b..5e776a6 100644
>> --- a/tests/ofproto-dpif.at
>> +++ b/tests/ofproto-dpif.at
>> @@ -9384,7 +9384,7 @@ 
>> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x8100),vlan(vid=99,pcp=
>>   # are wildcarded.
>>   AT_CHECK([grep '\(modify\)\|\(flow_add\)' ovs-vswitchd.log | 
>> strip_ufid ], [0], [dnl
>>   dpif_netdev|DBG|flow_add: 
>> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x1234), 
>> actions:100
>> -dpif|DBG|dummy@ovs-dummy: put[[modify]] 
>> skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234)
>> +dpif|DBG|dummy@ovs-dummy: put[[modify]] 
>> skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234), 
>> actions:drop
>>   dpif|DBG|dummy@ovs-dummy: put[[modify]] 
>> skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234), 
>> actions:100
>>   dpif_netdev|DBG|flow_add: 
>> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x8100),vlan(vid=99,pcp=7/0x0),encap(eth_type(0x1234)), 
>> actions:drop
>>   ])
>> diff --git a/tests/tunnel-push-pop.at b/tests/tunnel-push-pop.at
>> index f717243..532c44e 100644
>> --- a/tests/tunnel-push-pop.at
>> +++ b/tests/tunnel-push-pop.at
>> @@ -447,6 +447,28 @@ AT_CHECK([ovs-ofctl dump-ports int-br | grep 
>> 'port  7'], [0], [dnl
>>     port  7: rx pkts=3, bytes=252, drop=?, errs=?, frame=?, over=?, 
>> crc=?
>>   ])
>>   +AT_CHECK([ovs-appctl netdev-dummy/receive p0 
>> 'aa55aa550000001b213cab6408004500007079464000402fba600101025c0101025820000800000001c845000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
>> +
>> +ovs-appctl time/warp 5000
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "datapath_drop_tunnel_pop_error" | 
>> cut -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +sleep 1
>> +AT_CHECK([ovs-appctl netdev-dummy/receive p0 
>> 'aa55aa550000001b213cab6408004503007079464000402fba600101025c0101025820000800000001c845000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
>> +
>> +ovs-appctl time/warp 5000
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "drop_action_congestion" | cut -d':' 
>> -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>> +
>>   dnl Check GREL3 only accepts non-fragmented packets?
>>   AT_CHECK([ovs-appctl netdev-dummy/receive p0 
>> 'aa55aa550000001b213cab6408004500007e79464000402fba550101025c0101025820000800000001c8fe71d883724fbeb6f4e1494a080045000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
>>   @@ -455,7 +477,7 @@ ovs-appctl time/warp 1000
>>     AT_CHECK([ovs-ofctl dump-ports int-br | grep 'port  [[37]]' | 
>> sort], [0], [dnl
>>     port  3: rx pkts=3, bytes=294, drop=?, errs=?, frame=?, over=?, 
>> crc=?
>> -  port  7: rx pkts=4, bytes=350, drop=?, errs=?, frame=?, over=?, crc=?
>> +  port  7: rx pkts=5, bytes=434, drop=?, errs=?, frame=?, over=?, crc=?
>>   ])
>>     dnl Check decapsulation of Geneve packet with options
>> @@ -478,7 +500,7 @@ AT_CHECK([ovs-ofctl dump-ports int-br | grep 
>> 'port  5'], [0], [dnl
>>     port  5: rx pkts=1, bytes=98, drop=?, errs=?, frame=?, over=?, crc=?
>>   ])
>>   AT_CHECK([ovs-appctl dpif/dump-flows int-br | grep 
>> 'in_port(6081)'], [0], [dnl
>> -tunnel(tun_id=0x7b,src=1.1.2.92,dst=1.1.2.88,geneve({class=0xffff,type=0x80,len=4,0xa/0xf}{class=0xffff,type=0,len=4}),flags(-df-csum+key)),recirc_id(0),in_port(6081),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
>> packets:0, bytes:0, used:never, 
>> actions:userspace(pid=0,controller(reason=1,dont_send=0,continuation=0,recirc_id=3,rule_cookie=0,controller_id=0,max_len=65535))
>> +tunnel(tun_id=0x7b,src=1.1.2.92,dst=1.1.2.88,geneve({class=0xffff,type=0x80,len=4,0xa/0xf}{class=0xffff,type=0,len=4}),flags(-df-csum+key)),recirc_id(0),in_port(6081),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
>> packets:0, bytes:0, used:never, 
>> actions:userspace(pid=0,controller(reason=1,dont_send=0,continuation=0,recirc_id=2,rule_cookie=0,controller_id=0,max_len=65535))
>>   ])
>>     ovs-appctl time/warp 10000
>> @@ -510,7 +532,8 @@ AT_CHECK([ovs-appctl tnl/ports/show |sort], [0], 
>> [dnl
>>   Listening ports:
>>   ])
>>   -OVS_VSWITCHD_STOP
>> +OVS_VSWITCHD_STOP(["/dropping tunnel packet marked ECN CE but is not 
>> ECN capable/d
>> +/ip packet has invalid checksum/d"])
>>   AT_CLEANUP
>>     AT_SETUP([tunnel_push_pop - packet_out])
>> diff --git a/tests/tunnel.at b/tests/tunnel.at
>> index 035c54f..8b663e9 100644
>> --- a/tests/tunnel.at
>> +++ b/tests/tunnel.at
>> @@ -102,9 +102,10 @@ Datapath actions: set(ipv4(tos=0x3/0x3)),2
>>     dnl Tunnel CE and encapsulated packet Non-ECT
>>   AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 
>> 'tunnel(src=1.1.1.1,dst=2.2.2.2,tos=0x3,ttl=64,flags()),in_port(1),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0,ttl=64,frag=no),tcp(src=8,dst=9)'], 
>> [0], [stdout])
>> -AT_CHECK([tail -2 stdout], [0],
>> +AT_CHECK([tail -3 stdout], [0],
>>     [Megaflow: 
>> recirc_id=0,eth,ip,tun_id=0,tun_src=1.1.1.1,tun_dst=2.2.2.2,tun_tos=3,tun_flags=-df-csum-key,in_port=1,nw_ecn=0,nw_frag=no
>>   Datapath actions: drop
>> +Translation failed (Congestion Drop), packet is dropped.
>>   ])
>>   OVS_VSWITCHD_STOP(["/dropping tunnel packet marked ECN CE but is 
>> not ECN capable/d"])
>>   AT_CLEANUP
>> @@ -193,6 +194,17 @@ AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 
>> 'in_port(2),eth(src=50:54:00:00:00:
>>   AT_CHECK([tail -1 stdout], [0],
>>     [Datapath actions: 
>> set(tunnel(tun_id=0x5,src=2.2.2.2,dst=1.1.1.1,ttl=64,flags(df|key))),set(skb_mark(0x2)),1
>>   ])
>> +
>> +AT_CHECK([ovs-appctl netdev-dummy/receive p2 
>> 'aa55aa550001f8bc124434b6080045000054ba20000040018486010103580101037001004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
>> +
>> +sleep 2
>> +
>> +AT_CHECK([
>> +ovs-appctl coverage/show | grep "datapath_drop_invalid_port" | cut 
>> -d':' -f2|sed 's/ //'
>> +], [0], [dnl
>> +1
>> +])
>> +
>>   OVS_VSWITCHD_STOP
>>   AT_CLEANUP
>

On 7 Jun 2019, at 7:27, Anju Thomas wrote:

Did a quick review, and I noticed some styling issues (mainly 
indentation), the rest seems ok. One small issue with applying the 
patchset to master, but nothing a manual inspection could quickly fix.

Did some basic testing by forcing some of the drops, and seems to work 
fine.

Will do a more thorough review on next patch, including tests. See also 
Gregory Rose’s comments.

//Eelco


> Currently OVS maintains explicit packet drop/error counters only on 
> port level.
> Packets that are dropped as part of normal OpenFlow processing are 
> counted in flow stats of “drop” flows or as table misses in table 
> stats.
> These can only be interpreted by controllers that know the semantics 
> of the configured OpenFlow pipeline. Without that knowledge, it is 
> impossible for an OVS user to obtain e.g. the total number of packets 
> dropped due to OpenFlow rules.
>
> Furthermore, there are numerous other reasons for which packets can be 
> dropped by OVS slow path that are not related to the OpenFlow 
> pipeline.
> The generated datapath flow entries include a drop action to avoid 
> further expensive upcalls to the slow path, but subsequent packets 
> dropped by the datapath are not accounted anywhere.
>
> Finally, the datapath itself drops packets in certain error 
> situations.
> Also, these drops are today not accounted for.
>
> This makes it difficult for OVS users to monitor packet drop in an OVS 
> instance and to alert a management system in case of a unexpected 
> increase of such drops. Also OVS trouble-shooters face difficulties in 
> analysing packet drops.
>
> With this patch we implement following changes to address the issues 
> mentioned above.
>
> 1. Identify and account all the silent packet drop scenarios
>
> 2. Display these drops in ovs-appctl coverage/show

Please add some details on the explicit drop actions added

>
> A detailed presentation on this was presented at OvS conference 2017 
> and link for the corresponding presentation is available at:
>
> https://www.slideshare.net/LF_OpenvSwitch/lfovs17troubleshooting-the-data-plane-in-ovs-82280329
>
> Co-authored-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
> Co-authored-by: Keshav Gupta <keshugupta1@gmail.com>
> Signed-off-by: Anju Thomas <anju.thomas@ericsson.com>
> Signed-off-by: Rohith Basavaraja <rohith.basavaraja@gmail.com>
> Signed-off-by: Keshav Gupta <keshugupta1@gmail.com>
> ---
>  datapath/linux/compat/include/linux/openvswitch.h |   1 +
>  lib/dpif-netdev.c                                 |  46 ++++-
>  lib/dpif.c                                        |   7 +
>  lib/dpif.h                                        |   4 +
>  lib/odp-execute.c                                 |  78 ++++++++
>  lib/odp-util.c                                    |   9 +
>  ofproto/ofproto-dpif-ipfix.c                      |   1 +
>  ofproto/ofproto-dpif-sflow.c                      |   1 +
>  ofproto/ofproto-dpif-xlate.c                      |  34 +++-
>  ofproto/ofproto-dpif-xlate.h                      |   3 +
>  ofproto/ofproto-dpif.c                            |   7 +
>  ofproto/ofproto-dpif.h                            |   8 +-
>  tests/automake.mk                                 |   3 +-
>  tests/dpif-netdev.at                              |   8 +
>  tests/drop-stats.at                               | 211 
> ++++++++++++++++++++++
>  tests/ofproto-dpif.at                             |   2 +-
>  tests/tunnel-push-pop.at                          |  29 ++-
>  tests/tunnel.at                                   |  14 +-
>  18 files changed, 455 insertions(+), 11 deletions(-)
>  create mode 100644 tests/drop-stats.at
>
> diff --git a/datapath/linux/compat/include/linux/openvswitch.h 
> b/datapath/linux/compat/include/linux/openvswitch.h
> index 65a003a..2de702e 100644
> --- a/datapath/linux/compat/include/linux/openvswitch.h
> +++ b/datapath/linux/compat/include/linux/openvswitch.h
> @@ -985,6 +985,7 @@ enum ovs_action_attr {
>  	OVS_ACTION_ATTR_METER,        /* u32 meter number. */
>  	OVS_ACTION_ATTR_CLONE,        /* Nested OVS_CLONE_ATTR_*.  */
>  	OVS_ACTION_ATTR_CHECK_PKT_LEN, /* Nested OVS_CHECK_PKT_LEN_ATTR_*. 
> */
> +    OVS_ACTION_ATTR_DROP,

Indentation
>
>  #ifndef __KERNEL__
>  	OVS_ACTION_ATTR_TUNNEL_PUSH,   /* struct ovs_action_push_tnl*/
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index 5a6f2ab..ec72403 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -101,6 +101,17 @@ enum { MAX_METERS = 65536 };    /* Maximum number 
> of meters. */
>  enum { MAX_BANDS = 8 };         /* Maximum number of bands / meter. 
> */
>  enum { N_METER_LOCKS = 64 };    /* Maximum number of meters. */
>
> +COVERAGE_DEFINE(datapath_drop_meter);
> +COVERAGE_DEFINE(datapath_drop_upcall_error);
> +COVERAGE_DEFINE(datapath_drop_lock_error);
> +COVERAGE_DEFINE(datapath_drop_userspace_action_error);
> +COVERAGE_DEFINE(datapath_drop_tunnel_push_error);
> +COVERAGE_DEFINE(datapath_drop_tunnel_pop_error);
> +COVERAGE_DEFINE(datapath_drop_recirc_error);
> +COVERAGE_DEFINE(datapath_drop_invalid_port);
> +COVERAGE_DEFINE(datapath_drop_invalid_tnl_port);
> +COVERAGE_DEFINE(datapath_drop_rx_invalid_packet);
> +
>  /* Protects against changes to 'dp_netdevs'. */
>  static struct ovs_mutex dp_netdev_mutex = OVS_MUTEX_INITIALIZER;
>
> @@ -5646,7 +5657,7 @@ dp_netdev_run_meter(struct dp_netdev *dp, struct 
> dp_packet_batch *packets_,
>              band = &meter->bands[exceeded_band[j]];
>              band->packet_count += 1;
>              band->byte_count += dp_packet_size(packet);
> -
> +            COVERAGE_INC(datapath_drop_meter);
>              dp_packet_delete(packet);
>          } else {
>              /* Meter accepts packet. */
> @@ -6402,6 +6413,7 @@ dfc_processing(struct dp_netdev_pmd_thread *pmd,
>
>          if (OVS_UNLIKELY(dp_packet_size(packet) < ETH_HEADER_LEN)) {
>              dp_packet_delete(packet);
> +            COVERAGE_INC(datapath_drop_rx_invalid_packet);
>              continue;
>          }
>
> @@ -6521,6 +6533,7 @@ handle_packet_upcall(struct dp_netdev_pmd_thread 
> *pmd,
>                               put_actions);
>      if (OVS_UNLIKELY(error && error != ENOSPC)) {
>          dp_packet_delete(packet);
> +        COVERAGE_INC(datapath_drop_upcall_error);
>          return error;
>      }
>
> @@ -6651,6 +6664,7 @@ fast_path_processing(struct dp_netdev_pmd_thread 
> *pmd,
>          DP_PACKET_BATCH_FOR_EACH (i, packet, packets_) {
>              if (OVS_UNLIKELY(!rules[i])) {
>                  dp_packet_delete(packet);
> +                COVERAGE_INC(datapath_drop_lock_error);
>                  upcall_fail_cnt++;
>              }
>          }
> @@ -6920,6 +6934,7 @@ dp_execute_userspace_action(struct 
> dp_netdev_pmd_thread *pmd,
>                                    actions->data, actions->size);
>      } else if (should_steal) {
>          dp_packet_delete(packet);
> +        COVERAGE_INC(datapath_drop_userspace_action_error);
>      }
>  }
>
> @@ -6934,6 +6949,7 @@ dp_execute_cb(void *aux_, struct dp_packet_batch 
> *packets_,
>      struct dp_netdev *dp = pmd->dp;
>      int type = nl_attr_type(a);
>      struct tx_port *p;
> +    uint32_t packet_count, packet_dropped;
>
>      switch ((enum ovs_action_attr)type) {
>      case OVS_ACTION_ATTR_OUTPUT:
> @@ -6975,6 +6991,9 @@ dp_execute_cb(void *aux_, struct dp_packet_batch 
> *packets_,
>                  dp_packet_batch_add(&p->output_pkts, packet);
>              }
>              return;
> +        } else {
> +            COVERAGE_ADD(datapath_drop_invalid_port,
> +                            dp_packet_batch_size(packets_));
Indentation
>          }
>          break;
>
> @@ -6984,10 +7003,16 @@ dp_execute_cb(void *aux_, struct 
> dp_packet_batch *packets_,
>               * the ownership of these packets. Thus, we can avoid 
> performing
>               * the action, because the caller will not use the result 
> anyway.
>               * Just break to free the batch. */
> +            COVERAGE_ADD(datapath_drop_tunnel_push_error,
> +                            dp_packet_batch_size(packets_));
Indentation
>              break;
>          }
>          dp_packet_batch_apply_cutlen(packets_);
> -        push_tnl_action(pmd, a, packets_);
> +        packet_count = dp_packet_batch_size(packets_);
> +        if (push_tnl_action(pmd, a, packets_)) {
> +            COVERAGE_ADD(datapath_drop_tunnel_push_error,
> +                            packet_count);
> +        }
>          return;
>
>      case OVS_ACTION_ATTR_TUNNEL_POP:
> @@ -7007,7 +7032,13 @@ dp_execute_cb(void *aux_, struct 
> dp_packet_batch *packets_,
>
>                  dp_packet_batch_apply_cutlen(packets_);
>
> +                packet_count = dp_packet_batch_size(packets_);
>                  netdev_pop_header(p->port->netdev, packets_);
> +                packet_dropped = packet_count - packets_->count;
> +                if (packet_dropped) {
> +                    COVERAGE_ADD(datapath_drop_tunnel_pop_error,
> +                                     packet_dropped);
Indentation
> +                }
>                  if (dp_packet_batch_is_empty(packets_)) {
>                      return;
>                  }
> @@ -7022,6 +7053,11 @@ dp_execute_cb(void *aux_, struct 
> dp_packet_batch *packets_,
>                  (*depth)--;
>                  return;
>              }
> +            COVERAGE_ADD(datapath_drop_invalid_tnl_port,
> +                            dp_packet_batch_size(packets_));
Indentation
> +        } else {
> +            COVERAGE_ADD(datapath_drop_recirc_error,
> +                            dp_packet_batch_size(packets_));
Indentation
>          }
>          break;
>
> @@ -7066,6 +7102,9 @@ dp_execute_cb(void *aux_, struct dp_packet_batch 
> *packets_,
>
>              return;
>          }
> +        COVERAGE_ADD(datapath_drop_lock_error,
> +                        dp_packet_batch_size(packets_));
Indentation
> +
>          break;
>
>      case OVS_ACTION_ATTR_RECIRC:
> @@ -7089,6 +7128,8 @@ dp_execute_cb(void *aux_, struct dp_packet_batch 
> *packets_,
>              return;
>          }
>
> +        COVERAGE_ADD(datapath_drop_recirc_error,
> +                        dp_packet_batch_size(packets_));
Indentation
>          VLOG_WARN("Packet dropped. Max recirculation depth 
> exceeded.");
>          break;
>
> @@ -7242,6 +7283,7 @@ dp_execute_cb(void *aux_, struct dp_packet_batch 
> *packets_,
>      case OVS_ACTION_ATTR_POP_NSH:
>      case OVS_ACTION_ATTR_CT_CLEAR:
>      case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +    case OVS_ACTION_ATTR_DROP:
>      case __OVS_ACTION_ATTR_MAX:
>          OVS_NOT_REACHED();
>      }
> diff --git a/lib/dpif.c b/lib/dpif.c
> index a18fb1b..112e9d1 100644
> --- a/lib/dpif.c
> +++ b/lib/dpif.c
> @@ -1267,6 +1267,7 @@ dpif_execute_helper_cb(void *aux_, struct 
> dp_packet_batch *packets_,
>      case OVS_ACTION_ATTR_CT_CLEAR:
>      case OVS_ACTION_ATTR_UNSPEC:
>      case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +    case OVS_ACTION_ATTR_DROP:
>      case __OVS_ACTION_ATTR_MAX:
>          OVS_NOT_REACHED();
>      }
> @@ -1872,6 +1873,12 @@ dpif_supports_tnl_push_pop(const struct dpif 
> *dpif)
>      return dpif_is_netdev(dpif);
>  }
>
> +bool
> +dpif_supports_explicit_drop_action(const struct dpif *dpif) {
> +    return dpif_is_netdev(dpif);
> +}
> +
> +
>  /* Meters */
>  void
>  dpif_meter_get_features(const struct dpif *dpif,
> diff --git a/lib/dpif.h b/lib/dpif.h
> index 475d5a6..4b9a434 100644
> --- a/lib/dpif.h
> +++ b/lib/dpif.h
> @@ -888,6 +888,10 @@ int dpif_get_pmds_for_port(const struct dpif * 
> dpif, odp_port_t port_no,
>
>  char *dpif_get_dp_version(const struct dpif *);
>  bool dpif_supports_tnl_push_pop(const struct dpif *);
> +bool dpif_supports_explicit_drop_action(const struct dpif *);
> +int dpif_show_drop_stats_support(struct dpif *dpif, bool detail,
> +                          struct ds *reply);
Indentation
> +
>
>  /* Log functions. */
>  struct vlog_module;<
> diff --git a/lib/odp-execute.c b/lib/odp-execute.c
> index 563ad1d..e243e89 100644
> --- a/lib/odp-execute.c
> +++ b/lib/odp-execute.c
> @@ -25,6 +25,7 @@
>  #include <stdlib.h>
>  #include <string.h>
>
> +#include "coverage.h"
>  #include "dp-packet.h"
>  #include "dpif.h"
>  #include "netlink.h"
> @@ -36,6 +37,72 @@
>  #include "util.h"
>  #include "csum.h"
>  #include "conntrack.h"
> +#include "ofproto/ofproto-dpif-xlate.h"
> +#include "openvswitch/vlog.h"
> +
> +VLOG_DEFINE_THIS_MODULE(odp_execute)
> +COVERAGE_DEFINE(datapath_drop_sample_error);
> +COVERAGE_DEFINE(datapath_drop_nsh_decap_error);
> +COVERAGE_DEFINE(drop_action_of_pipeline);
> +COVERAGE_DEFINE(drop_action_bridge_not_found);
> +COVERAGE_DEFINE(drop_action_recursion_too_deep);
> +COVERAGE_DEFINE(drop_action_too_many_resubmit);
> +COVERAGE_DEFINE(drop_action_stack_too_deep);
> +COVERAGE_DEFINE(drop_action_no_recirculation_context);
> +COVERAGE_DEFINE(drop_action_recirculation_conflict);
> +COVERAGE_DEFINE(drop_action_too_many_mpls_labels);
> +COVERAGE_DEFINE(drop_action_invalid_tunnel_metadata);
> +COVERAGE_DEFINE(drop_action_unsupported_packet_type);
> +COVERAGE_DEFINE(drop_action_congestion);
> +COVERAGE_DEFINE(drop_action_forwarding_disabled);
> +
> +static void
> +dp_update_drop_action_counter(enum xlate_error drop_reason,
> +                                 int delta) {
Indentation
> +   static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
> +
> +   switch (drop_reason) {
> +   case XLATE_OK:
> +        COVERAGE_ADD(drop_action_of_pipeline, delta);
> +        break;
> +   case XLATE_BRIDGE_NOT_FOUND:
> +        COVERAGE_ADD(drop_action_bridge_not_found, delta);
> +        break;
> +   case XLATE_RECURSION_TOO_DEEP:
> +        COVERAGE_ADD(drop_action_recursion_too_deep, delta);
> +        break;
> +   case XLATE_TOO_MANY_RESUBMITS:
> +        COVERAGE_ADD(drop_action_too_many_resubmit, delta);
> +        break;
> +   case XLATE_STACK_TOO_DEEP:
> +        COVERAGE_ADD(drop_action_stack_too_deep, delta);
> +        break;
> +   case XLATE_NO_RECIRCULATION_CONTEXT:
> +        COVERAGE_ADD(drop_action_no_recirculation_context, delta);
> +        break;
> +   case XLATE_RECIRCULATION_CONFLICT:
> +        COVERAGE_ADD(drop_action_recirculation_conflict, delta);
> +        break;
> +   case XLATE_TOO_MANY_MPLS_LABELS:
> +        COVERAGE_ADD(drop_action_too_many_mpls_labels, delta);
> +        break;
> +   case XLATE_INVALID_TUNNEL_METADATA:
> +        COVERAGE_ADD(drop_action_invalid_tunnel_metadata, delta);
> +        break;
> +   case XLATE_UNSUPPORTED_PACKET_TYPE:
> +        COVERAGE_ADD(drop_action_unsupported_packet_type, delta);
> +        break;
> +   case XLATE_CONGESTION_DROP:
> +        COVERAGE_ADD(drop_action_congestion, delta);
> +        break;
> +   case XLATE_FORWARDING_DISABLED:
> +        COVERAGE_ADD(drop_action_forwarding_disabled, delta);
> +        break;
> +   case XLATE_MAX:
> +   default:
> +        VLOG_ERR_RL(&rl, "Invalid Drop reason type:%d", drop_reason);
> +   }
> +}
>
>  /* Masked copy of an ethernet address. 'src' is already properly 
> masked. */
>  static void
> @@ -621,6 +688,7 @@ odp_execute_sample(void *dp, struct dp_packet 
> *packet, bool steal,
>          case OVS_SAMPLE_ATTR_PROBABILITY:
>              if (random_uint32() >= nl_attr_get_u32(a)) {
>                  if (steal) {
> +                    COVERAGE_ADD(datapath_drop_sample_error, 1);
>                      dp_packet_delete(packet);
>                  }
>                  return;
> @@ -749,6 +817,7 @@ requires_datapath_assistance(const struct nlattr 
> *a)
>      case OVS_ACTION_ATTR_POP_NSH:
>      case OVS_ACTION_ATTR_CT_CLEAR:
>      case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +    case OVS_ACTION_ATTR_DROP:
>          return false;
>
>      case OVS_ACTION_ATTR_UNSPEC:
> @@ -965,6 +1034,7 @@ odp_execute_actions(void *dp, struct 
> dp_packet_batch *batch, bool steal,
>                  if (pop_nsh(packet)) {
>                      dp_packet_batch_refill(batch, packet, i);
>                  } else {
> +                    COVERAGE_INC(datapath_drop_nsh_decap_error);
>                      dp_packet_delete(packet);
>                  }
>              }
> @@ -989,6 +1059,14 @@ odp_execute_actions(void *dp, struct 
> dp_packet_batch *batch, bool steal,
>              }
>              break;
>
> +        case OVS_ACTION_ATTR_DROP:{
> +            const enum xlate_error *drop_reason = nl_attr_get(a);
> +            if (*drop_reason < XLATE_MAX) {
> +                 dp_update_drop_action_counter(*drop_reason, 
> batch->count);
> +            }
> +            dp_packet_delete_batch(batch, steal);
> +            return;
> +        }
>          case OVS_ACTION_ATTR_OUTPUT:
>          case OVS_ACTION_ATTR_TUNNEL_PUSH:
>          case OVS_ACTION_ATTR_TUNNEL_POP:
> diff --git a/lib/odp-util.c b/lib/odp-util.c
> index 3a28877..0dbb6d9 100644
> --- a/lib/odp-util.c
> +++ b/lib/odp-util.c
> @@ -44,6 +44,7 @@
>  #include "openvswitch/vlog.h"
>  #include "openvswitch/match.h"
>  #include "odp-netlink-macros.h"
> +#include "ofproto/ofproto-dpif-xlate.h"
>
>  VLOG_DEFINE_THIS_MODULE(odp_util);
>
> @@ -140,6 +141,7 @@ odp_action_len(uint16_t type)
>      case OVS_ACTION_ATTR_PUSH_NSH: return ATTR_LEN_VARIABLE;
>      case OVS_ACTION_ATTR_POP_NSH: return 0;
>      case OVS_ACTION_ATTR_CHECK_PKT_LEN: return ATTR_LEN_VARIABLE;
> +    case OVS_ACTION_ATTR_DROP: return sizeof(enum xlate_error);
>
>      case OVS_ACTION_ATTR_UNSPEC:
>      case __OVS_ACTION_ATTR_MAX:
> @@ -1230,6 +1232,9 @@ format_odp_action(struct ds *ds, const struct 
> nlattr *a,
>      case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>          format_odp_check_pkt_len_action(ds, a, portno_names);
>          break;
> +    case OVS_ACTION_ATTR_DROP:
> +        ds_put_cstr(ds, "drop");
> +        break;
>      case OVS_ACTION_ATTR_UNSPEC:
>      case __OVS_ACTION_ATTR_MAX:
>      default:
> @@ -2547,8 +2552,12 @@ odp_actions_from_string(const char *s, const 
> struct simap *port_names,
>                          struct ofpbuf *actions)
>  {
>      size_t old_size;
> +    enum xlate_error drop_action;
>
>      if (!strcasecmp(s, "drop")) {
> +        drop_action = XLATE_OK;
> +        nl_msg_put_unspec(actions, OVS_ACTION_ATTR_DROP,
> +                          &drop_action, sizeof drop_action);
>          return 0;
>      }
>
> diff --git a/ofproto/ofproto-dpif-ipfix.c 
> b/ofproto/ofproto-dpif-ipfix.c
> index b8bd1b8..b413768 100644
> --- a/ofproto/ofproto-dpif-ipfix.c
> +++ b/ofproto/ofproto-dpif-ipfix.c
> @@ -3016,6 +3016,7 @@ dpif_ipfix_read_actions(const struct flow *flow,
>          case OVS_ACTION_ATTR_POP_NSH:
>          case OVS_ACTION_ATTR_CHECK_PKT_LEN:
>          case OVS_ACTION_ATTR_UNSPEC:
> +        case OVS_ACTION_ATTR_DROP:
>          case __OVS_ACTION_ATTR_MAX:
>          default:
>              break;
> diff --git a/ofproto/ofproto-dpif-sflow.c 
> b/ofproto/ofproto-dpif-sflow.c
> index 03bd763..387e9b5 100644
> --- a/ofproto/ofproto-dpif-sflow.c
> +++ b/ofproto/ofproto-dpif-sflow.c
> @@ -1224,6 +1224,7 @@ dpif_sflow_read_actions(const struct flow *flow,
>          case OVS_ACTION_ATTR_POP_NSH:
>          case OVS_ACTION_ATTR_UNSPEC:
>          case OVS_ACTION_ATTR_CHECK_PKT_LEN:
> +        case OVS_ACTION_ATTR_DROP:
>          case __OVS_ACTION_ATTR_MAX:
>          default:
>              break;
> diff --git a/ofproto/ofproto-dpif-xlate.c 
> b/ofproto/ofproto-dpif-xlate.c
> index 5cee37f..1a9c6fe 100644
> --- a/ofproto/ofproto-dpif-xlate.c
> +++ b/ofproto/ofproto-dpif-xlate.c
> @@ -444,6 +444,12 @@ const char *xlate_strerror(enum xlate_error 
> error)
>          return "Invalid tunnel metadata";
>      case XLATE_UNSUPPORTED_PACKET_TYPE:
>          return "Unsupported packet type";
> +    case XLATE_CONGESTION_DROP:
> +        return "Congestion Drop";
> +    case XLATE_FORWARDING_DISABLED:
> +        return "Forwarding is disabled";
> +    case XLATE_MAX:
> +        break;
>      }
>      return "Unknown error";
>  }
> @@ -5943,6 +5949,13 @@ put_ct_label(const struct flow *flow, struct 
> ofpbuf *odp_actions,
>  }
>
>  static void
> +put_drop_action(struct ofpbuf *odp_actions, enum xlate_error error) {
> +    nl_msg_put_unspec(odp_actions, OVS_ACTION_ATTR_DROP,
> +                      &error, sizeof error);
> +
> +}
> +
> +static void
>  put_ct_helper(struct xlate_ctx *ctx,
>                struct ofpbuf *odp_actions, struct ofpact_conntrack 
> *ofc)
>  {
> @@ -7532,9 +7545,10 @@ xlate_actions(struct xlate_in *xin, struct 
> xlate_out *xout)
>              compose_ipfix_action(&ctx, ODPP_NONE);
>          }
>          size_t sample_actions_len = ctx.odp_actions->size;
> +        bool ecn_drop = !tnl_process_ecn(flow);
>
> -        if (tnl_process_ecn(flow)
> -            && (!in_port || may_receive(in_port, &ctx))) {
> +        if (!ecn_drop &&
> +                (!in_port || may_receive(in_port, &ctx))) {
Indentation, and && should be on the next line

>              const struct ofpact *ofpacts;
>              size_t ofpacts_len;
>
> @@ -7573,6 +7587,8 @@ xlate_actions(struct xlate_in *xin, struct 
> xlate_out *xout)
>              if (ctx.freezing) {
>                  finish_freezing(&ctx);
>              }
> +        } else if (ecn_drop) {
> +            ctx.error = XLATE_CONGESTION_DROP;
>          }
>
>          /* Output only fully processed packets. */
> @@ -7672,6 +7688,20 @@ exit:
>              ofpbuf_clear(xin->odp_actions);
>          }
>      }
> +
> +
> +    /*
> +     * If we are going to install "drop" action, check whether
> +     * datapath supports explicit "drop"action. If datapath
                                            ^ space
> +     * supports explicit "drop"action then install the "drop"
                                   ^space
> +     * action containing the drop reason.
> +     */
> +    if (xin->odp_actions && !xin->odp_actions->size &&
> +         <(ctx.xbridge->ofproto)) {
> +        put_drop_action(xin->odp_actions, ctx.error);
> +    }
> +
> +
>      return ctx.error;
>  }
>
> diff --git a/ofproto/ofproto-dpif-xlate.h 
> b/ofproto/ofproto-dpif-xlate.h
> index 5a51d7b..69b758b 100644
> --- a/ofproto/ofproto-dpif-xlate.h
> +++ b/ofproto/ofproto-dpif-xlate.h
> @@ -217,6 +217,9 @@ enum xlate_error {
>      XLATE_TOO_MANY_MPLS_LABELS,
>      XLATE_INVALID_TUNNEL_METADATA,
>      XLATE_UNSUPPORTED_PACKET_TYPE,
> +    XLATE_CONGESTION_DROP,
> +    XLATE_FORWARDING_DISABLED,

Where is XLATE_FORWARDING_DISABLED used?
> +    XLATE_MAX,
>  };
>
>  const char *xlate_strerror(enum xlate_error error);
> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> index db461ac..884ef52 100644
> --- a/ofproto/ofproto-dpif.c
> +++ b/ofproto/ofproto-dpif.c
> @@ -827,6 +827,11 @@ ovs_native_tunneling_is_on(struct ofproto_dpif 
> *ofproto)
>          && atomic_count_get(&ofproto->backer->tnl_count);
>  }
>
> +bool
> +ovs_explicit_drop_action_supported(struct ofproto_dpif *ofproto) {
> +    return ofproto->backer->rt_support.explicit_drop_action;
> +}
> +
>  /* Tests whether 'backer''s datapath supports recirculation.  Only 
> newer
>   * datapaths support OVS_KEY_ATTR_RECIRC_ID in keys.  We need to 
> disable some
>   * features on older datapaths that don't support this feature.
> @@ -1440,6 +1445,8 @@ check_support(struct dpif_backer *backer)
>      backer->rt_support.ct_clear = check_ct_clear(backer);
>      backer->rt_support.max_hash_alg = check_max_dp_hash_alg(backer);
>      backer->rt_support.check_pkt_len = check_check_pkt_len(backer);
> +    backer->rt_support.explicit_drop_action =
> +        dpif_supports_explicit_drop_action(backer->dpif);
>
>      /* Flow fields. */
>      backer->rt_support.odp.ct_state = check_ct_state(backer);
> diff --git a/ofproto/ofproto-dpif.h b/ofproto/ofproto-dpif.h
> index cd5321e..f2f0f20 100644
> --- a/ofproto/ofproto-dpif.h
> +++ b/ofproto/ofproto-dpif.h
> @@ -195,7 +195,11 @@ struct group_dpif *group_dpif_lookup(struct 
> ofproto_dpif *,
>      DPIF_SUPPORT_FIELD(size_t, max_hash_alg, "Max dp_hash algorithm") 
>       \
>                                                                              \
>      /* True if the datapath supports OVS_ACTION_ATTR_CHECK_PKT_LEN. 
> */   \
> -    DPIF_SUPPORT_FIELD(bool, check_pkt_len, "Check pkt length 
> action")
> +    DPIF_SUPPORT_FIELD(bool, check_pkt_len, "Check pkt length 
> action")     \
> +                                                                      
>       \
> +    /* True if the datapath supports explicit drop action. */         
>       \
> +    DPIF_SUPPORT_FIELD(bool, explicit_drop_action, "Explicit Drop 
> action")
> +
>
>  /* Stores the various features which the corresponding backer 
> supports. */
>  struct dpif_backer_support {
> @@ -364,4 +368,6 @@ int ofproto_dpif_delete_internal_flow(struct 
> ofproto_dpif *, struct match *,
>
>  bool ovs_native_tunneling_is_on(struct ofproto_dpif *);
>
> +bool ovs_explicit_drop_action_supported(struct ofproto_dpif *);
> +
>  #endif /* ofproto-dpif.h */
> diff --git a/tests/automake.mk b/tests/automake.mk
> index ea16532..dd67b57 100644
> --- a/tests/automake.mk
> +++ b/tests/automake.mk
> @@ -109,7 +109,8 @@ TESTSUITE_AT = \
>  	tests/ovn-controller-vtep.at \
>  	tests/mcast-snooping.at \
>  	tests/packet-type-aware.at \
> -	tests/nsh.at
> +	tests/nsh.at \
> +	tests/drop-stats.at
>
>  EXTRA_DIST += $(FUZZ_REGRESSION_TESTS)
>  FUZZ_REGRESSION_TESTS = \
> diff --git a/tests/dpif-netdev.at b/tests/dpif-netdev.at
> index 039ee97..e6e0ed8 100644
> --- a/tests/dpif-netdev.at
> +++ b/tests/dpif-netdev.at
> @@ -349,6 +349,14 @@ meter:2 flow_count:1 packet_in_count:10 
> byte_in_count:600 duration:0.0s bands:
>  0: packet_count:5 byte_count:300
>  ])
>
> +ovs-appctl time/warp 5000
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "datapath_drop_meter" | cut -d':' 
> -f2|sed 's/ //'
> +], [0], [dnl
> +14
> +])
> +
>  AT_CHECK([cat ovs-vswitchd.log | filter_flow_install | 
> strip_xout_keep_actions], [0], [dnl
>  recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
> actions:meter(0),7
>  recirc_id(0),in_port(2),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
> actions:8
> diff --git a/tests/drop-stats.at b/tests/drop-stats.at
> new file mode 100644
> index 0000000..b94354d
> --- /dev/null
> +++ b/tests/drop-stats.at
> @@ -0,0 +1,211 @@
> +AT_BANNER([drop-stats])
> +
> +AT_SETUP([drop-stats - cli tests])
> +
> +OVS_VSWITCHD_START([dnl
> +    set bridge br0 datapath_type=dummy \
> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1])
> +
> +AT_DATA([flows.txt], [dnl
> +table=0,in_port=1,actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
> +actions ], [0], [dnl
> + in_port=1 actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1 
> 1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e08006f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +    ovs-appctl netdev-dummy/receive p1 
> 1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e08006f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +AT_CHECK([ovs-appctl dpctl/dump-flows | sed
> +'s/used:[[0-9]].[[0-9]]*s/used:0.0/' | sort], [0], [flow-dump from 
> non-dpdk interfaces:
> +recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(fr
> +ag=no), packets:2, bytes:196, used:0.0, actions:drop
> +])
> +
> +sleep 1
> +
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_of_pipeline" | cut -d':' 
> -f2|sed 's/ //'
> +], [0], [dnl
> +3
> +])
> +
> +
> +OVS_VSWITCHD_STOP
> +AT_CLEANUP
> +
> +AT_SETUP([drop-stats - pipeline and recurssion drops])
> +
> +OVS_VSWITCHD_START([dnl
> +    set bridge br0 datapath_type=dummy \
> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1 
> -- \
> +    add-port br0 p2 -- set Interface p2 type=dummy ofport_request=2])
> +
> +AT_DATA([flows.txt], [dnl
> +table=0,in_port=1,actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
> +actions ], [0], [dnl
> + in_port=1 actions=drop
> +])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +sleep 1
> +
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_of_pipeline" | cut -d':' 
> -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +AT_DATA([flows.txt], [dnl
> +table=0, in_port=1, actions=goto_table:1 table=1, in_port=1,
> +actions=goto_table:2 table=2, in_port=1, actions=resubmit(,1)
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +    ovs-ofctl -Oopenflow13 dump-flows br0 | ofctl_strip | sort | grep
> +actions ], [0], [ignore])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_recursion_too_deep" | 
> cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
> +AT_CLEANUP
> +
> +AT_SETUP([drop-stats - too many resubmit])
> +
> +OVS_VSWITCHD_START
> +add_of_ports br0 1
> +(for i in `seq 1 64`; do
> +     j=`expr $i + 1`
> +     echo "in_port=$i, actions=resubmit:$j, resubmit:$j, local"
> + done
> + echo "in_port=65, actions=local") > flows.txt
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt ], [0], [ignore])
> +
> +ovs-appctl netdev-dummy/receive p1 
> 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x1234)'
> +
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_too_many_resubmit" | cut 
> -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
> +AT_CLEANUP
> +
> +
> +AT_SETUP([drop-stats - stack too deep]) OVS_VSWITCHD_START 
> add_of_ports
> +br0 1 (for i in `seq 1 12`; do
> +     j=`expr $i + 1`
> +     echo "in_port=$i, actions=resubmit:$j, resubmit:$j, local"
> + done
> + push="push:NXM_NX_REG0[[]]"
> + echo "in_port=13,
> +actions=$push,$push,$push,$push,$push,$push,$push,$push") > flows
> +AT_CHECK([ovs-ofctl add-flows br0 flows])
> +
> +ovs-appctl netdev-dummy/receive p1 
> 'in_port(1),eth(src=50:54:00:00:00:09,dst=50:54:00:00:00:0a),eth_type(0x1234)'
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_stack_too_deep" | cut 
> -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +OVS_VSWITCHD_STOP(["/resubmits yielded over 64 kB of stack/d"])
> +AT_CLEANUP
> +
> +AT_SETUP([drop-stats - too many mpls labels])
> +
> +OVS_VSWITCHD_START([dnl
> +    set bridge br0 datapath_type=dummy \
> +        protocols=OpenFlow10,OpenFlow13,OpenFlow14,OpenFlow15 -- \
> +    add-port br0 p1 -- set Interface p1 type=dummy ofport_request=1 
> -- \
> +    add-port br0 p2 -- set Interface p2 type=dummy ofport_request=2])
> +
> +AT_DATA([flows.txt], [dnl
> +table=0, in_port=1, actions=push_mpls:0x8847, resubmit:3 table=0,
> +in_port=3, actions=push_mpls:0x8847, set_field:10->mpls_label,
> +set_field:15->mpls_label,  resubmit:4 table=0, in_port=4,
> +actions=push_mpls:0x8847, set_field:11->mpls_label, resubmit:5 
> table=0,
> +in_port=5, actions=push_mpls:0x8847, set_field:12->mpls_label,
> +resubmit:6 table=0, in_port=6, actions=push_mpls:0x8847,
> +set_field:13->mpls_label, output:2
> +])
> +
> +AT_CHECK([
> +    ovs-ofctl del-flows br0
> +    ovs-ofctl -Oopenflow13 add-flows br0 flows.txt
> +])
> +
> +AT_CHECK([
> +    ovs-appctl netdev-dummy/receive p1
> +1e2ce92a669e3a6dd2099cab0800450000548a53400040011addc0a80a0ac0a80a1e080
> +06f200a4d0001fc509a58000000002715020000000000101112131415161718191a1b1c
> +1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637
> +], [0], [ignore])
> +
> +sleep 1
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_too_many_mpls_labels" | 
> cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
> +OVS_VSWITCHD_STOP(["/|WARN|/d"])
> +AT_CLEANUP
> +
> diff --git a/tests/ofproto-dpif.at b/tests/ofproto-dpif.at
> index 9b0231b..5e776a6 100644
> --- a/tests/ofproto-dpif.at
> +++ b/tests/ofproto-dpif.at
> @@ -9384,7 +9384,7 @@ 
> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x8100),vlan(vid=99,pcp=
>  # are wildcarded.
>  AT_CHECK([grep '\(modify\)\|\(flow_add\)' ovs-vswitchd.log | 
> strip_ufid ], [0], [dnl
>  dpif_netdev|DBG|flow_add: 
> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x1234), 
> actions:100
> -dpif|DBG|dummy@ovs-dummy: put[[modify]] 
> skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234)
> +dpif|DBG|dummy@ovs-dummy: put[[modify]] 
> skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234), 
> actions:drop
>  dpif|DBG|dummy@ovs-dummy: put[[modify]] 
> skb_priority(0/0),skb_mark(0/0),ct_state(0/0),ct_zone(0/0),ct_mark(0/0),ct_label(0/0),recirc_id(0),dp_hash(0/0),in_port(1),packet_type(ns=0,id=0),eth(src=50:54:00:00:00:09/00:00:00:00:00:00,dst=50:54:00:00:00:0a/00:00:00:00:00:00),eth_type(0x1234), 
> actions:100
>  dpif_netdev|DBG|flow_add: 
> recirc_id(0),in_port(1),packet_type(ns=0,id=0),eth_type(0x8100),vlan(vid=99,pcp=7/0x0),encap(eth_type(0x1234)), 
> actions:drop
>  ])
> diff --git a/tests/tunnel-push-pop.at b/tests/tunnel-push-pop.at
> index f717243..532c44e 100644
> --- a/tests/tunnel-push-pop.at
> +++ b/tests/tunnel-push-pop.at
> @@ -447,6 +447,28 @@ AT_CHECK([ovs-ofctl dump-ports int-br | grep 
> 'port  7'], [0], [dnl
>    port  7: rx pkts=3, bytes=252, drop=?, errs=?, frame=?, over=?, 
> crc=?
>  ])
>
> +AT_CHECK([ovs-appctl netdev-dummy/receive p0 
> 'aa55aa550000001b213cab6408004500007079464000402fba600101025c0101025820000800000001c845000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
> +
> +ovs-appctl time/warp 5000
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "datapath_drop_tunnel_pop_error" | 
> cut -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +sleep 1
> +AT_CHECK([ovs-appctl netdev-dummy/receive p0 
> 'aa55aa550000001b213cab6408004503007079464000402fba600101025c0101025820000800000001c845000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
> +
> +ovs-appctl time/warp 5000
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "drop_action_congestion" | cut -d':' 
> -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
> +
>  dnl Check GREL3 only accepts non-fragmented packets?
>  AT_CHECK([ovs-appctl netdev-dummy/receive p0 
> 'aa55aa550000001b213cab6408004500007e79464000402fba550101025c0101025820000800000001c8fe71d883724fbeb6f4e1494a080045000054ba200000400184861e0000011e00000200004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
>
> @@ -455,7 +477,7 @@ ovs-appctl time/warp 1000
>
>  AT_CHECK([ovs-ofctl dump-ports int-br | grep 'port  [[37]]' | sort], 
> [0], [dnl
>    port  3: rx pkts=3, bytes=294, drop=?, errs=?, frame=?, over=?, 
> crc=?
> -  port  7: rx pkts=4, bytes=350, drop=?, errs=?, frame=?, over=?, 
> crc=?
> +  port  7: rx pkts=5, bytes=434, drop=?, errs=?, frame=?, over=?, 
> crc=?
>  ])
>
>  dnl Check decapsulation of Geneve packet with options
> @@ -478,7 +500,7 @@ AT_CHECK([ovs-ofctl dump-ports int-br | grep 'port 
>  5'], [0], [dnl
>    port  5: rx pkts=1, bytes=98, drop=?, errs=?, frame=?, over=?, 
> crc=?
>  ])
>  AT_CHECK([ovs-appctl dpif/dump-flows int-br | grep 'in_port(6081)'], 
> [0], [dnl
> -tunnel(tun_id=0x7b,src=1.1.2.92,dst=1.1.2.88,geneve({class=0xffff,type=0x80,len=4,0xa/0xf}{class=0xffff,type=0,len=4}),flags(-df-csum+key)),recirc_id(0),in_port(6081),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
> packets:0, bytes:0, used:never, 
> actions:userspace(pid=0,controller(reason=1,dont_send=0,continuation=0,recirc_id=3,rule_cookie=0,controller_id=0,max_len=65535))
> +tunnel(tun_id=0x7b,src=1.1.2.92,dst=1.1.2.88,geneve({class=0xffff,type=0x80,len=4,0xa/0xf}{class=0xffff,type=0,len=4}),flags(-df-csum+key)),recirc_id(0),in_port(6081),packet_type(ns=0,id=0),eth_type(0x0800),ipv4(frag=no), 
> packets:0, bytes:0, used:never, 
> actions:userspace(pid=0,controller(reason=1,dont_send=0,continuation=0,recirc_id=2,rule_cookie=0,controller_id=0,max_len=65535))
>  ])
>
>  ovs-appctl time/warp 10000
> @@ -510,7 +532,8 @@ AT_CHECK([ovs-appctl tnl/ports/show |sort], [0], 
> [dnl
>  Listening ports:
>  ])
>
> -OVS_VSWITCHD_STOP
> +OVS_VSWITCHD_STOP(["/dropping tunnel packet marked ECN CE but is not 
> ECN capable/d
> +/ip packet has invalid checksum/d"])
>  AT_CLEANUP
>
>  AT_SETUP([tunnel_push_pop - packet_out])
> diff --git a/tests/tunnel.at b/tests/tunnel.at
> index 035c54f..8b663e9 100644
> --- a/tests/tunnel.at
> +++ b/tests/tunnel.at
> @@ -102,9 +102,10 @@ Datapath actions: set(ipv4(tos=0x3/0x3)),2
>
>  dnl Tunnel CE and encapsulated packet Non-ECT
>  AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 
> 'tunnel(src=1.1.1.1,dst=2.2.2.2,tos=0x3,ttl=64,flags()),in_port(1),eth(src=50:54:00:00:00:05,dst=50:54:00:00:00:07),eth_type(0x0800),ipv4(src=192.168.0.1,dst=192.168.0.2,proto=6,tos=0,ttl=64,frag=no),tcp(src=8,dst=9)'], 
> [0], [stdout])
> -AT_CHECK([tail -2 stdout], [0],
> +AT_CHECK([tail -3 stdout], [0],
>    [Megaflow: 
> recirc_id=0,eth,ip,tun_id=0,tun_src=1.1.1.1,tun_dst=2.2.2.2,tun_tos=3,tun_flags=-df-csum-key,in_port=1,nw_ecn=0,nw_frag=no
>  Datapath actions: drop
> +Translation failed (Congestion Drop), packet is dropped.
>  ])
>  OVS_VSWITCHD_STOP(["/dropping tunnel packet marked ECN CE but is not 
> ECN capable/d"])
>  AT_CLEANUP
> @@ -193,6 +194,17 @@ AT_CHECK([ovs-appctl ofproto/trace ovs-dummy 
> 'in_port(2),eth(src=50:54:00:00:00:
>  AT_CHECK([tail -1 stdout], [0],
>    [Datapath actions: 
> set(tunnel(tun_id=0x5,src=2.2.2.2,dst=1.1.1.1,ttl=64,flags(df|key))),set(skb_mark(0x2)),1
>  ])
> +
> +AT_CHECK([ovs-appctl netdev-dummy/receive p2 
> 'aa55aa550001f8bc124434b6080045000054ba20000040018486010103580101037001004227e75400030af3195500000000f265010000000000101112131415161718191a1b1c1d1e1f202122232425262728292a2b2c2d2e2f3031323334353637'])
> +
> +sleep 2
> +
> +AT_CHECK([
> +ovs-appctl coverage/show | grep "datapath_drop_invalid_port" | cut 
> -d':' -f2|sed 's/ //'
> +], [0], [dnl
> +1
> +])
> +
>  OVS_VSWITCHD_STOP
>  AT_CLEANUP
>
> -- 
> 1.9.1
>
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