/*
 * Copyright (c) 2009, 2010, 2011 Nicira Networks.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <config.h>

#include "ofproto/private.h"

#include <errno.h>

#include "autopath.h"
#include "bond.h"
#include "byte-order.h"
#include "connmgr.h"
#include "coverage.h"
#include "cfm.h"
#include "dpif.h"
#include "dynamic-string.h"
#include "fail-open.h"
#include "hmapx.h"
#include "lacp.h"
#include "mac-learning.h"
#include "multipath.h"
#include "netdev.h"
#include "netlink.h"
#include "nx-match.h"
#include "odp-util.h"
#include "ofp-util.h"
#include "ofpbuf.h"
#include "ofp-print.h"
#include "ofproto-sflow.h"
#include "poll-loop.h"
#include "timer.h"
#include "unaligned.h"
#include "unixctl.h"
#include "vlan-bitmap.h"
#include "vlog.h"

VLOG_DEFINE_THIS_MODULE(ofproto_dpif);

COVERAGE_DEFINE(ofproto_dpif_ctlr_action);
COVERAGE_DEFINE(ofproto_dpif_expired);
COVERAGE_DEFINE(ofproto_dpif_no_packet_in);
COVERAGE_DEFINE(ofproto_dpif_xlate);
COVERAGE_DEFINE(facet_changed_rule);
COVERAGE_DEFINE(facet_invalidated);
COVERAGE_DEFINE(facet_revalidate);
COVERAGE_DEFINE(facet_unexpected);

/* Maximum depth of flow table recursion (due to NXAST_RESUBMIT actions) in a
 * flow translation. */
#define MAX_RESUBMIT_RECURSION 16

struct ofport_dpif;
struct ofproto_dpif;

struct rule_dpif {
    struct rule up;

    long long int used;         /* Time last used; time created if not used. */

    /* These statistics:
     *
     *   - Do include packets and bytes from facets that have been deleted or
     *     whose own statistics have been folded into the rule.
     *
     *   - Do include packets and bytes sent "by hand" that were accounted to
     *     the rule without any facet being involved (this is a rare corner
     *     case in rule_execute()).
     *
     *   - Do not include packet or bytes that can be obtained from any facet's
     *     packet_count or byte_count member or that can be obtained from the
     *     datapath by, e.g., dpif_flow_get() for any facet.
     */
    uint64_t packet_count;       /* Number of packets received. */
    uint64_t byte_count;         /* Number of bytes received. */

    struct list facets;          /* List of "struct facet"s. */
};

static struct rule_dpif *rule_dpif_cast(const struct rule *rule)
{
    return rule ? CONTAINER_OF(rule, struct rule_dpif, up) : NULL;
}

static struct rule_dpif *rule_dpif_lookup(struct ofproto_dpif *ofproto,
                                          const struct flow *flow);

#define MAX_MIRRORS 32
typedef uint32_t mirror_mask_t;
#define MIRROR_MASK_C(X) UINT32_C(X)
BUILD_ASSERT_DECL(sizeof(mirror_mask_t) * CHAR_BIT >= MAX_MIRRORS);
struct ofmirror {
    struct ofproto_dpif *ofproto; /* Owning ofproto. */
    size_t idx;                 /* In ofproto's "mirrors" array. */
    void *aux;                  /* Key supplied by ofproto's client. */
    char *name;                 /* Identifier for log messages. */

    /* Selection criteria. */
    struct hmapx srcs;          /* Contains "struct ofbundle *"s. */
    struct hmapx dsts;          /* Contains "struct ofbundle *"s. */
    unsigned long *vlans;       /* Bitmap of chosen VLANs, NULL selects all. */

    /* Output (mutually exclusive). */
    struct ofbundle *out;       /* Output port or NULL. */
    int out_vlan;               /* Output VLAN or -1. */
};

static void mirror_destroy(struct ofmirror *);

/* A group of one or more OpenFlow ports. */
#define OFBUNDLE_FLOOD ((struct ofbundle *) 1)
struct ofbundle {
    struct ofproto_dpif *ofproto; /* Owning ofproto. */
    struct hmap_node hmap_node; /* In struct ofproto's "bundles" hmap. */
    void *aux;                  /* Key supplied by ofproto's client. */
    char *name;                 /* Identifier for log messages. */

    /* Configuration. */
    struct list ports;          /* Contains "struct ofport"s. */
    int vlan;                   /* -1=trunk port, else a 12-bit VLAN ID. */
    unsigned long *trunks;      /* Bitmap of trunked VLANs, if 'vlan' == -1.
                                 * NULL if all VLANs are trunked. */
    struct lacp *lacp;          /* LACP if LACP is enabled, otherwise NULL. */
    struct bond *bond;          /* Nonnull iff more than one port. */

    /* Status. */
    bool floodable;             /* True if no port has OFPPC_NO_FLOOD set. */

    /* Port mirroring info. */
    mirror_mask_t src_mirrors;  /* Mirrors triggered when packet received. */
    mirror_mask_t dst_mirrors;  /* Mirrors triggered when packet sent. */
    mirror_mask_t mirror_out;   /* Mirrors that output to this bundle. */
};

static void bundle_remove(struct ofport *);
static void bundle_destroy(struct ofbundle *);
static void bundle_del_port(struct ofport_dpif *);
static void bundle_run(struct ofbundle *);
static void bundle_wait(struct ofbundle *);

struct action_xlate_ctx {
/* action_xlate_ctx_init() initializes these members. */

    /* The ofproto. */
    struct ofproto_dpif *ofproto;

    /* Flow to which the OpenFlow actions apply.  xlate_actions() will modify
     * this flow when actions change header fields. */
    struct flow flow;

    /* The packet corresponding to 'flow', or a null pointer if we are
     * revalidating without a packet to refer to. */
    const struct ofpbuf *packet;

    /* If nonnull, called just before executing a resubmit action.
     *
     * This is normally null so the client has to set it manually after
     * calling action_xlate_ctx_init(). */
    void (*resubmit_hook)(struct action_xlate_ctx *, struct rule_dpif *);

/* xlate_actions() initializes and uses these members.  The client might want
 * to look at them after it returns. */

    struct ofpbuf *odp_actions; /* Datapath actions. */
    tag_type tags;              /* Tags associated with OFPP_NORMAL actions. */
    bool may_set_up_flow;       /* True ordinarily; false if the actions must
                                 * be reassessed for every packet. */
    uint16_t nf_output_iface;   /* Output interface index for NetFlow. */

/* xlate_actions() initializes and uses these members, but the client has no
 * reason to look at them. */

    int recurse;                /* Recursion level, via xlate_table_action. */
    int last_pop_priority;      /* Offset in 'odp_actions' just past most
                                 * recent ODP_ACTION_ATTR_SET_PRIORITY. */
};

static void action_xlate_ctx_init(struct action_xlate_ctx *,
                                  struct ofproto_dpif *, const struct flow *,
                                  const struct ofpbuf *);
static struct ofpbuf *xlate_actions(struct action_xlate_ctx *,
                                    const union ofp_action *in, size_t n_in);

/* An exact-match instantiation of an OpenFlow flow. */
struct facet {
    long long int used;         /* Time last used; time created if not used. */

    /* These statistics:
     *
     *   - Do include packets and bytes sent "by hand", e.g. with
     *     dpif_execute().
     *
     *   - Do include packets and bytes that were obtained from the datapath
     *     when a flow was deleted (e.g. dpif_flow_del()) or when its
     *     statistics were reset (e.g. dpif_flow_put() with
     *     DPIF_FP_ZERO_STATS).
     *
     *   - Do not include any packets or bytes that can currently be obtained
     *     from the datapath by, e.g., dpif_flow_get().
     */
    uint64_t packet_count;       /* Number of packets received. */
    uint64_t byte_count;         /* Number of bytes received. */

    uint64_t dp_packet_count;    /* Last known packet count in the datapath. */
    uint64_t dp_byte_count;      /* Last known byte count in the datapath. */

    uint64_t rs_packet_count;    /* Packets pushed to resubmit children. */
    uint64_t rs_byte_count;      /* Bytes pushed to resubmit children. */
    long long int rs_used;       /* Used time pushed to resubmit children. */

    /* Number of bytes passed to account_cb.  This may include bytes that can
     * currently obtained from the datapath (thus, it can be greater than
     * byte_count). */
    uint64_t accounted_bytes;

    struct hmap_node hmap_node;  /* In owning ofproto's 'facets' hmap. */
    struct list list_node;       /* In owning rule's 'facets' list. */
    struct rule_dpif *rule;      /* Owning rule. */
    struct flow flow;            /* Exact-match flow. */
    bool installed;              /* Installed in datapath? */
    bool may_install;            /* True ordinarily; false if actions must
                                  * be reassessed for every packet. */
    size_t actions_len;          /* Number of bytes in actions[]. */
    struct nlattr *actions;      /* Datapath actions. */
    tag_type tags;               /* Tags. */
    struct netflow_flow nf_flow; /* Per-flow NetFlow tracking data. */
};

static struct facet *facet_create(struct rule_dpif *, const struct flow *,
                                  const struct ofpbuf *packet);
static void facet_remove(struct ofproto_dpif *, struct facet *);
static void facet_free(struct facet *);

static struct facet *facet_find(struct ofproto_dpif *, const struct flow *);
static struct facet *facet_lookup_valid(struct ofproto_dpif *,
                                        const struct flow *);
static bool facet_revalidate(struct ofproto_dpif *, struct facet *);

static void facet_execute(struct ofproto_dpif *, struct facet *,
                          struct ofpbuf *packet);

static int facet_put__(struct ofproto_dpif *, struct facet *,
                       const struct nlattr *actions, size_t actions_len,
                       struct dpif_flow_stats *);
static void facet_install(struct ofproto_dpif *, struct facet *,
                          bool zero_stats);
static void facet_uninstall(struct ofproto_dpif *, struct facet *);
static void facet_flush_stats(struct ofproto_dpif *, struct facet *);

static void facet_make_actions(struct ofproto_dpif *, struct facet *,
                               const struct ofpbuf *packet);
static void facet_update_time(struct ofproto_dpif *, struct facet *,
                              long long int used);
static void facet_update_stats(struct ofproto_dpif *, struct facet *,
                               const struct dpif_flow_stats *);
static void facet_push_stats(struct facet *);
static void facet_account(struct ofproto_dpif *, struct facet *,
                          uint64_t extra_bytes);

static bool facet_is_controller_flow(struct facet *);

static void flow_push_stats(const struct rule_dpif *,
                            struct flow *, uint64_t packets, uint64_t bytes,
                            long long int used);

struct ofport_dpif {
    struct ofport up;

    uint32_t odp_port;
    struct ofbundle *bundle;    /* Bundle that contains this port, if any. */
    struct list bundle_node;    /* In struct ofbundle's "ports" list. */
    struct cfm *cfm;            /* Connectivity Fault Management, if any. */
    tag_type tag;               /* Tag associated with this port. */
    uint32_t bond_stable_id;    /* stable_id to use as bond slave, or 0. */
};

static struct ofport_dpif *
ofport_dpif_cast(const struct ofport *ofport)
{
    assert(ofport->ofproto->ofproto_class == &ofproto_dpif_class);
    return ofport ? CONTAINER_OF(ofport, struct ofport_dpif, up) : NULL;
}

static void port_run(struct ofport_dpif *);
static void port_wait(struct ofport_dpif *);
static int set_cfm(struct ofport *, const struct cfm *,
                   const uint16_t *remote_mps, size_t n_remote_mps);

struct ofproto_dpif {
    struct ofproto up;
    struct dpif *dpif;
    int max_ports;

    /* Statistics. */
    uint64_t n_matches;

    /* Bridging. */
    struct netflow *netflow;
    struct ofproto_sflow *sflow;
    struct hmap bundles;        /* Contains "struct ofbundle"s. */
    struct mac_learning *ml;
    struct ofmirror *mirrors[MAX_MIRRORS];
    bool has_bonded_bundles;

    /* Expiration. */
    struct timer next_expiration;

    /* Facets. */
    struct hmap facets;
    bool need_revalidate;
    struct tag_set revalidate_set;
};

static void ofproto_dpif_unixctl_init(void);

static struct ofproto_dpif *
ofproto_dpif_cast(const struct ofproto *ofproto)
{
    assert(ofproto->ofproto_class == &ofproto_dpif_class);
    return CONTAINER_OF(ofproto, struct ofproto_dpif, up);
}

static struct ofport_dpif *get_ofp_port(struct ofproto_dpif *,
                                        uint16_t ofp_port);
static struct ofport_dpif *get_odp_port(struct ofproto_dpif *,
                                        uint32_t odp_port);

/* Packet processing. */
static void update_learning_table(struct ofproto_dpif *,
                                  const struct flow *, int vlan,
                                  struct ofbundle *);
static bool is_admissible(struct ofproto_dpif *, const struct flow *,
                          bool have_packet, tag_type *, int *vlanp,
                          struct ofbundle **in_bundlep);
static void handle_upcall(struct ofproto_dpif *, struct dpif_upcall *);

/* Flow expiration. */
static int expire(struct ofproto_dpif *);

/* Utilities. */
static int send_packet(struct ofproto_dpif *, uint32_t odp_port,
                       const struct ofpbuf *packet);

/* Global variables. */
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);

/* Factory functions. */

static void
enumerate_types(struct sset *types)
{
    dp_enumerate_types(types);
}

static int
enumerate_names(const char *type, struct sset *names)
{
    return dp_enumerate_names(type, names);
}

static int
del(const char *type, const char *name)
{
    struct dpif *dpif;
    int error;

    error = dpif_open(name, type, &dpif);
    if (!error) {
        error = dpif_delete(dpif);
        dpif_close(dpif);
    }
    return error;
}

/* Basic life-cycle. */

static struct ofproto *
alloc(void)
{
    struct ofproto_dpif *ofproto = xmalloc(sizeof *ofproto);
    return &ofproto->up;
}

static void
dealloc(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    free(ofproto);
}

static int
construct(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    const char *name = ofproto->up.name;
    int error;
    int i;

    error = dpif_create_and_open(name, ofproto->up.type, &ofproto->dpif);
    if (error) {
        VLOG_ERR("failed to open datapath %s: %s", name, strerror(error));
        return error;
    }

    ofproto->max_ports = dpif_get_max_ports(ofproto->dpif);
    ofproto->n_matches = 0;

    error = dpif_recv_set_mask(ofproto->dpif,
                               ((1u << DPIF_UC_MISS) |
                                (1u << DPIF_UC_ACTION) |
                                (1u << DPIF_UC_SAMPLE)));
    if (error) {
        VLOG_ERR("failed to listen on datapath %s: %s", name, strerror(error));
        dpif_close(ofproto->dpif);
        return error;
    }
    dpif_flow_flush(ofproto->dpif);
    dpif_recv_purge(ofproto->dpif);

    ofproto->netflow = NULL;
    ofproto->sflow = NULL;
    hmap_init(&ofproto->bundles);
    ofproto->ml = mac_learning_create();
    for (i = 0; i < MAX_MIRRORS; i++) {
        ofproto->mirrors[i] = NULL;
    }
    ofproto->has_bonded_bundles = false;

    timer_set_duration(&ofproto->next_expiration, 1000);

    hmap_init(&ofproto->facets);
    ofproto->need_revalidate = false;
    tag_set_init(&ofproto->revalidate_set);

    ofproto->up.tables = xmalloc(sizeof *ofproto->up.tables);
    classifier_init(&ofproto->up.tables[0]);
    ofproto->up.n_tables = 1;

    ofproto_dpif_unixctl_init();

    return 0;
}

static void
destruct(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    int i;

    for (i = 0; i < MAX_MIRRORS; i++) {
        mirror_destroy(ofproto->mirrors[i]);
    }

    netflow_destroy(ofproto->netflow);
    ofproto_sflow_destroy(ofproto->sflow);
    hmap_destroy(&ofproto->bundles);
    mac_learning_destroy(ofproto->ml);

    hmap_destroy(&ofproto->facets);

    dpif_close(ofproto->dpif);
}

static int
run(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct ofport_dpif *ofport;
    struct ofbundle *bundle;
    int i;

    dpif_run(ofproto->dpif);

    for (i = 0; i < 50; i++) {
        struct dpif_upcall packet;
        int error;

        error = dpif_recv(ofproto->dpif, &packet);
        if (error) {
            if (error == ENODEV) {
                /* Datapath destroyed. */
                return error;
            }
            break;
        }

        handle_upcall(ofproto, &packet);
    }

    if (timer_expired(&ofproto->next_expiration)) {
        int delay = expire(ofproto);
        timer_set_duration(&ofproto->next_expiration, delay);
    }

    if (ofproto->netflow) {
        netflow_run(ofproto->netflow);
    }
    if (ofproto->sflow) {
        ofproto_sflow_run(ofproto->sflow);
    }

    HMAP_FOR_EACH (ofport, up.hmap_node, &ofproto->up.ports) {
        port_run(ofport);
    }
    HMAP_FOR_EACH (bundle, hmap_node, &ofproto->bundles) {
        bundle_run(bundle);
    }

    /* Now revalidate if there's anything to do. */
    if (ofproto->need_revalidate
        || !tag_set_is_empty(&ofproto->revalidate_set)) {
        struct tag_set revalidate_set = ofproto->revalidate_set;
        bool revalidate_all = ofproto->need_revalidate;
        struct facet *facet, *next;

        /* Clear the revalidation flags. */
        tag_set_init(&ofproto->revalidate_set);
        ofproto->need_revalidate = false;

        HMAP_FOR_EACH_SAFE (facet, next, hmap_node, &ofproto->facets) {
            if (revalidate_all
                || tag_set_intersects(&revalidate_set, facet->tags)) {
                facet_revalidate(ofproto, facet);
            }
        }
    }

    return 0;
}

static void
wait(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct ofport_dpif *ofport;
    struct ofbundle *bundle;

    dpif_wait(ofproto->dpif);
    dpif_recv_wait(ofproto->dpif);
    if (ofproto->sflow) {
        ofproto_sflow_wait(ofproto->sflow);
    }
    if (!tag_set_is_empty(&ofproto->revalidate_set)) {
        poll_immediate_wake();
    }
    HMAP_FOR_EACH (ofport, up.hmap_node, &ofproto->up.ports) {
        port_wait(ofport);
    }
    HMAP_FOR_EACH (bundle, hmap_node, &ofproto->bundles) {
        bundle_wait(bundle);
    }
    if (ofproto->need_revalidate) {
        /* Shouldn't happen, but if it does just go around again. */
        VLOG_DBG_RL(&rl, "need revalidate in ofproto_wait_cb()");
        poll_immediate_wake();
    } else {
        timer_wait(&ofproto->next_expiration);
    }
}

static void
flush(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct facet *facet, *next_facet;

    HMAP_FOR_EACH_SAFE (facet, next_facet, hmap_node, &ofproto->facets) {
        /* Mark the facet as not installed so that facet_remove() doesn't
         * bother trying to uninstall it.  There is no point in uninstalling it
         * individually since we are about to blow away all the facets with
         * dpif_flow_flush(). */
        facet->installed = false;
        facet->dp_packet_count = 0;
        facet->dp_byte_count = 0;
        facet_remove(ofproto, facet);
    }
    dpif_flow_flush(ofproto->dpif);
}

static void
get_features(struct ofproto *ofproto_ OVS_UNUSED,
             bool *arp_match_ip, uint32_t *actions)
{
    *arp_match_ip = true;
    *actions = ((1u << OFPAT_OUTPUT) |
                (1u << OFPAT_SET_VLAN_VID) |
                (1u << OFPAT_SET_VLAN_PCP) |
                (1u << OFPAT_STRIP_VLAN) |
                (1u << OFPAT_SET_DL_SRC) |
                (1u << OFPAT_SET_DL_DST) |
                (1u << OFPAT_SET_NW_SRC) |
                (1u << OFPAT_SET_NW_DST) |
                (1u << OFPAT_SET_NW_TOS) |
                (1u << OFPAT_SET_TP_SRC) |
                (1u << OFPAT_SET_TP_DST) |
                (1u << OFPAT_ENQUEUE));
}

static void
get_tables(struct ofproto *ofproto_, struct ofp_table_stats *ots)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct odp_stats s;

    strcpy(ots->name, "classifier");

    dpif_get_dp_stats(ofproto->dpif, &s);
    put_32aligned_be64(&ots->lookup_count, htonll(s.n_hit + s.n_missed));
    put_32aligned_be64(&ots->matched_count,
                       htonll(s.n_hit + ofproto->n_matches));
}

static int
set_netflow(struct ofproto *ofproto_,
            const struct netflow_options *netflow_options)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);

    if (netflow_options) {
        if (!ofproto->netflow) {
            ofproto->netflow = netflow_create();
        }
        return netflow_set_options(ofproto->netflow, netflow_options);
    } else {
        netflow_destroy(ofproto->netflow);
        ofproto->netflow = NULL;
        return 0;
    }
}

static struct ofport *
port_alloc(void)
{
    struct ofport_dpif *port = xmalloc(sizeof *port);
    return &port->up;
}

static void
port_dealloc(struct ofport *port_)
{
    struct ofport_dpif *port = ofport_dpif_cast(port_);
    free(port);
}

static int
port_construct(struct ofport *port_)
{
    struct ofport_dpif *port = ofport_dpif_cast(port_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(port->up.ofproto);

    port->odp_port = ofp_port_to_odp_port(port->up.ofp_port);
    port->bundle = NULL;
    port->cfm = NULL;
    port->tag = tag_create_random();

    if (ofproto->sflow) {
        ofproto_sflow_add_port(ofproto->sflow, port->odp_port,
                               netdev_get_name(port->up.netdev));
    }

    return 0;
}

static void
port_destruct(struct ofport *port_)
{
    struct ofport_dpif *port = ofport_dpif_cast(port_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(port->up.ofproto);

    bundle_remove(port_);
    set_cfm(port_, NULL, NULL, 0);
    if (ofproto->sflow) {
        ofproto_sflow_del_port(ofproto->sflow, port->odp_port);
    }
}

static void
port_modified(struct ofport *port_)
{
    struct ofport_dpif *port = ofport_dpif_cast(port_);

    if (port->bundle && port->bundle->bond) {
        bond_slave_set_netdev(port->bundle->bond, port, port->up.netdev);
    }
}

static void
port_reconfigured(struct ofport *port_, ovs_be32 old_config)
{
    struct ofport_dpif *port = ofport_dpif_cast(port_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(port->up.ofproto);
    ovs_be32 changed = old_config ^ port->up.opp.config;

    if (changed & htonl(OFPPC_NO_RECV | OFPPC_NO_RECV_STP |
                        OFPPC_NO_FWD | OFPPC_NO_FLOOD)) {
        ofproto->need_revalidate = true;
    }
}

static int
set_sflow(struct ofproto *ofproto_,
          const struct ofproto_sflow_options *sflow_options)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct ofproto_sflow *os = ofproto->sflow;
    if (sflow_options) {
        if (!os) {
            struct ofport_dpif *ofport;

            os = ofproto->sflow = ofproto_sflow_create(ofproto->dpif);
            HMAP_FOR_EACH (ofport, up.hmap_node, &ofproto->up.ports) {
                ofproto_sflow_add_port(os, ofport->odp_port,
                                       netdev_get_name(ofport->up.netdev));
            }
        }
        ofproto_sflow_set_options(os, sflow_options);
    } else {
        ofproto_sflow_destroy(os);
        ofproto->sflow = NULL;
    }
    return 0;
}

static int
set_cfm(struct ofport *ofport_, const struct cfm *cfm,
        const uint16_t *remote_mps, size_t n_remote_mps)
{
    struct ofport_dpif *ofport = ofport_dpif_cast(ofport_);
    int error;

    if (!cfm) {
        error = 0;
    } else {
        if (!ofport->cfm) {
            ofport->cfm = cfm_create();
        }

        ofport->cfm->mpid = cfm->mpid;
        ofport->cfm->interval = cfm->interval;
        memcpy(ofport->cfm->maid, cfm->maid, CCM_MAID_LEN);

        cfm_update_remote_mps(ofport->cfm, remote_mps, n_remote_mps);

        if (cfm_configure(ofport->cfm)) {
            return 0;
        }

        error = EINVAL;
    }
    cfm_destroy(ofport->cfm);
    ofport->cfm = NULL;
    return error;
}

static int
get_cfm(struct ofport *ofport_, const struct cfm **cfmp)
{
    struct ofport_dpif *ofport = ofport_dpif_cast(ofport_);
    *cfmp = ofport->cfm;
    return 0;
}

/* Bundles. */

/* Expires all MAC learning entries associated with 'port' and forces ofproto
 * to revalidate every flow. */
static void
bundle_flush_macs(struct ofbundle *bundle)
{
    struct ofproto_dpif *ofproto = bundle->ofproto;
    struct mac_learning *ml = ofproto->ml;
    struct mac_entry *mac, *next_mac;

    ofproto->need_revalidate = true;
    LIST_FOR_EACH_SAFE (mac, next_mac, lru_node, &ml->lrus) {
        if (mac->port.p == bundle) {
            mac_learning_expire(ml, mac);
        }
    }
}

static struct ofbundle *
bundle_lookup(const struct ofproto_dpif *ofproto, void *aux)
{
    struct ofbundle *bundle;

    HMAP_FOR_EACH_IN_BUCKET (bundle, hmap_node, hash_pointer(aux, 0),
                             &ofproto->bundles) {
        if (bundle->aux == aux) {
            return bundle;
        }
    }
    return NULL;
}

/* Looks up each of the 'n_auxes' pointers in 'auxes' as bundles and adds the
 * ones that are found to 'bundles'. */
static void
bundle_lookup_multiple(struct ofproto_dpif *ofproto,
                       void **auxes, size_t n_auxes,
                       struct hmapx *bundles)
{
    size_t i;

    hmapx_init(bundles);
    for (i = 0; i < n_auxes; i++) {
        struct ofbundle *bundle = bundle_lookup(ofproto, auxes[i]);
        if (bundle) {
            hmapx_add(bundles, bundle);
        }
    }
}

static void
bundle_del_port(struct ofport_dpif *port)
{
    struct ofbundle *bundle = port->bundle;

    bundle->ofproto->need_revalidate = true;

    list_remove(&port->bundle_node);
    port->bundle = NULL;

    if (bundle->lacp) {
        lacp_slave_unregister(bundle->lacp, port);
    }
    if (bundle->bond) {
        bond_slave_unregister(bundle->bond, port);
    }

    bundle->floodable = true;
    LIST_FOR_EACH (port, bundle_node, &bundle->ports) {
        if (port->up.opp.config & htonl(OFPPC_NO_FLOOD)) {
            bundle->floodable = false;
        }
    }
}

static bool
bundle_add_port(struct ofbundle *bundle, uint32_t ofp_port,
                struct lacp_slave_settings *lacp,
                uint32_t bond_stable_id)
{
    struct ofport_dpif *port;

    port = get_ofp_port(bundle->ofproto, ofp_port);
    if (!port) {
        return false;
    }

    if (port->bundle != bundle) {
        bundle->ofproto->need_revalidate = true;
        if (port->bundle) {
            bundle_del_port(port);
        }

        port->bundle = bundle;
        list_push_back(&bundle->ports, &port->bundle_node);
        if (port->up.opp.config & htonl(OFPPC_NO_FLOOD)) {
            bundle->floodable = false;
        }
    }
    if (lacp) {
        lacp_slave_register(bundle->lacp, port, lacp);
    }

    port->bond_stable_id = bond_stable_id;

    return true;
}

static void
bundle_destroy(struct ofbundle *bundle)
{
    struct ofproto_dpif *ofproto;
    struct ofport_dpif *port, *next_port;
    int i;

    if (!bundle) {
        return;
    }

    ofproto = bundle->ofproto;
    for (i = 0; i < MAX_MIRRORS; i++) {
        struct ofmirror *m = ofproto->mirrors[i];
        if (m) {
            if (m->out == bundle) {
                mirror_destroy(m);
            } else if (hmapx_find_and_delete(&m->srcs, bundle)
                       || hmapx_find_and_delete(&m->dsts, bundle)) {
                ofproto->need_revalidate = true;
            }
        }
    }

    LIST_FOR_EACH_SAFE (port, next_port, bundle_node, &bundle->ports) {
        bundle_del_port(port);
    }

    bundle_flush_macs(bundle);
    hmap_remove(&ofproto->bundles, &bundle->hmap_node);
    free(bundle->name);
    free(bundle->trunks);
    lacp_destroy(bundle->lacp);
    bond_destroy(bundle->bond);
    free(bundle);
}

static int
bundle_set(struct ofproto *ofproto_, void *aux,
           const struct ofproto_bundle_settings *s)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    bool need_flush = false;
    const unsigned long *trunks;
    struct ofport_dpif *port;
    struct ofbundle *bundle;
    size_t i;
    bool ok;

    if (!s) {
        bundle_destroy(bundle_lookup(ofproto, aux));
        return 0;
    }

    assert(s->n_slaves == 1 || s->bond != NULL);
    assert((s->lacp != NULL) == (s->lacp_slaves != NULL));

    bundle = bundle_lookup(ofproto, aux);
    if (!bundle) {
        bundle = xmalloc(sizeof *bundle);

        bundle->ofproto = ofproto;
        hmap_insert(&ofproto->bundles, &bundle->hmap_node,
                    hash_pointer(aux, 0));
        bundle->aux = aux;
        bundle->name = NULL;

        list_init(&bundle->ports);
        bundle->vlan = -1;
        bundle->trunks = NULL;
        bundle->lacp = NULL;
        bundle->bond = NULL;

        bundle->floodable = true;

        bundle->src_mirrors = 0;
        bundle->dst_mirrors = 0;
        bundle->mirror_out = 0;
    }

    if (!bundle->name || strcmp(s->name, bundle->name)) {
        free(bundle->name);
        bundle->name = xstrdup(s->name);
    }

    /* LACP. */
    if (s->lacp) {
        if (!bundle->lacp) {
            bundle->lacp = lacp_create();
        }
        lacp_configure(bundle->lacp, s->lacp);
    } else {
        lacp_destroy(bundle->lacp);
        bundle->lacp = NULL;
    }

    /* Update set of ports. */
    ok = true;
    for (i = 0; i < s->n_slaves; i++) {
        if (!bundle_add_port(bundle, s->slaves[i],
                             s->lacp ? &s->lacp_slaves[i] : NULL,
                             s->bond_stable_ids ? s->bond_stable_ids[i] : 0)) {
            ok = false;
        }
    }
    if (!ok || list_size(&bundle->ports) != s->n_slaves) {
        struct ofport_dpif *next_port;

        LIST_FOR_EACH_SAFE (port, next_port, bundle_node, &bundle->ports) {
            for (i = 0; i < s->n_slaves; i++) {
                if (s->slaves[i] == port->up.ofp_port) {
                    goto found;
                }
            }

            bundle_del_port(port);
        found: ;
        }
    }
    assert(list_size(&bundle->ports) <= s->n_slaves);

    if (list_is_empty(&bundle->ports)) {
        bundle_destroy(bundle);
        return EINVAL;
    }

    /* Set VLAN tag. */
    if (s->vlan != bundle->vlan) {
        bundle->vlan = s->vlan;
        need_flush = true;
    }

    /* Get trunked VLANs. */
    trunks = s->vlan == -1 ? NULL : s->trunks;
    if (!vlan_bitmap_equal(trunks, bundle->trunks)) {
        free(bundle->trunks);
        bundle->trunks = vlan_bitmap_clone(trunks);
        need_flush = true;
    }

    /* Bonding. */
    if (!list_is_short(&bundle->ports)) {
        bundle->ofproto->has_bonded_bundles = true;
        if (bundle->bond) {
            if (bond_reconfigure(bundle->bond, s->bond)) {
                ofproto->need_revalidate = true;
            }
        } else {
            bundle->bond = bond_create(s->bond);
            ofproto->need_revalidate = true;
        }

        LIST_FOR_EACH (port, bundle_node, &bundle->ports) {
            bond_slave_register(bundle->bond, port, port->bond_stable_id,
                                port->up.netdev);
        }
    } else {
        bond_destroy(bundle->bond);
        bundle->bond = NULL;
    }

    /* If we changed something that would affect MAC learning, un-learn
     * everything on this port and force flow revalidation. */
    if (need_flush) {
        bundle_flush_macs(bundle);
    }

    return 0;
}

static void
bundle_remove(struct ofport *port_)
{
    struct ofport_dpif *port = ofport_dpif_cast(port_);
    struct ofbundle *bundle = port->bundle;

    if (bundle) {
        bundle_del_port(port);
        if (list_is_empty(&bundle->ports)) {
            bundle_destroy(bundle);
        } else if (list_is_short(&bundle->ports)) {
            bond_destroy(bundle->bond);
            bundle->bond = NULL;
        }
    }
}

static void
send_pdu_cb(void *port_, const struct lacp_pdu *pdu)
{
    static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 10);
    struct ofport_dpif *port = port_;
    uint8_t ea[ETH_ADDR_LEN];
    int error;

    error = netdev_get_etheraddr(port->up.netdev, ea);
    if (!error) {
        struct lacp_pdu *packet_pdu;
        struct ofpbuf packet;

        ofpbuf_init(&packet, 0);
        packet_pdu = eth_compose(&packet, eth_addr_lacp, ea, ETH_TYPE_LACP,
                                 sizeof *packet_pdu);
        *packet_pdu = *pdu;
        error = netdev_send(port->up.netdev, &packet);
        if (error) {
            VLOG_WARN_RL(&rl, "port %s: sending LACP PDU on iface %s failed "
                         "(%s)", port->bundle->name,
                         netdev_get_name(port->up.netdev), strerror(error));
        }
        ofpbuf_uninit(&packet);
    } else {
        VLOG_ERR_RL(&rl, "port %s: cannot obtain Ethernet address of iface "
                    "%s (%s)", port->bundle->name,
                    netdev_get_name(port->up.netdev), strerror(error));
    }
}

static void
bundle_send_learning_packets(struct ofbundle *bundle)
{
    struct ofproto_dpif *ofproto = bundle->ofproto;
    int error, n_packets, n_errors;
    struct mac_entry *e;

    error = n_packets = n_errors = 0;
    LIST_FOR_EACH (e, lru_node, &ofproto->ml->lrus) {
        if (e->port.p != bundle) {
            int ret = bond_send_learning_packet(bundle->bond, e->mac, e->vlan);
            if (ret) {
                error = ret;
                n_errors++;
            }
            n_packets++;
        }
    }

    if (n_errors) {
        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
        VLOG_WARN_RL(&rl, "bond %s: %d errors sending %d gratuitous learning "
                     "packets, last error was: %s",
                     bundle->name, n_errors, n_packets, strerror(error));
    } else {
        VLOG_DBG("bond %s: sent %d gratuitous learning packets",
                 bundle->name, n_packets);
    }
}

static void
bundle_run(struct ofbundle *bundle)
{
    if (bundle->lacp) {
        lacp_run(bundle->lacp, send_pdu_cb);
    }
    if (bundle->bond) {
        struct ofport_dpif *port;

        LIST_FOR_EACH (port, bundle_node, &bundle->ports) {
            bool may_enable = lacp_slave_may_enable(bundle->lacp, port);
            bond_slave_set_lacp_may_enable(bundle->bond, port, may_enable);
        }

        bond_run(bundle->bond, &bundle->ofproto->revalidate_set,
                 lacp_negotiated(bundle->lacp));
        if (bond_should_send_learning_packets(bundle->bond)) {
            bundle_send_learning_packets(bundle);
        }
    }
}

static void
bundle_wait(struct ofbundle *bundle)
{
    if (bundle->lacp) {
        lacp_wait(bundle->lacp);
    }
    if (bundle->bond) {
        bond_wait(bundle->bond);
    }
}

/* Mirrors. */

static int
mirror_scan(struct ofproto_dpif *ofproto)
{
    int idx;

    for (idx = 0; idx < MAX_MIRRORS; idx++) {
        if (!ofproto->mirrors[idx]) {
            return idx;
        }
    }
    return -1;
}

static struct ofmirror *
mirror_lookup(struct ofproto_dpif *ofproto, void *aux)
{
    int i;

    for (i = 0; i < MAX_MIRRORS; i++) {
        struct ofmirror *mirror = ofproto->mirrors[i];
        if (mirror && mirror->aux == aux) {
            return mirror;
        }
    }

    return NULL;
}

static int
mirror_set(struct ofproto *ofproto_, void *aux,
           const struct ofproto_mirror_settings *s)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    mirror_mask_t mirror_bit;
    struct ofbundle *bundle;
    struct ofmirror *mirror;
    struct ofbundle *out;
    struct hmapx srcs;          /* Contains "struct ofbundle *"s. */
    struct hmapx dsts;          /* Contains "struct ofbundle *"s. */
    int out_vlan;

    mirror = mirror_lookup(ofproto, aux);
    if (!s) {
        mirror_destroy(mirror);
        return 0;
    }
    if (!mirror) {
        int idx;

        idx = mirror_scan(ofproto);
        if (idx < 0) {
            VLOG_WARN("bridge %s: maximum of %d port mirrors reached, "
                      "cannot create %s",
                      ofproto->up.name, MAX_MIRRORS, s->name);
            return EFBIG;
        }

        mirror = ofproto->mirrors[idx] = xzalloc(sizeof *mirror);
        mirror->ofproto = ofproto;
        mirror->idx = idx;
        mirror->out_vlan = -1;
        mirror->name = NULL;
    }

    if (!mirror->name || strcmp(s->name, mirror->name)) {
        free(mirror->name);
        mirror->name = xstrdup(s->name);
    }

    /* Get the new configuration. */
    if (s->out_bundle) {
        out = bundle_lookup(ofproto, s->out_bundle);
        if (!out) {
            mirror_destroy(mirror);
            return EINVAL;
        }
        out_vlan = -1;
    } else {
        out = NULL;
        out_vlan = s->out_vlan;
    }
    bundle_lookup_multiple(ofproto, s->srcs, s->n_srcs, &srcs);
    bundle_lookup_multiple(ofproto, s->dsts, s->n_dsts, &dsts);

    /* If the configuration has not changed, do nothing. */
    if (hmapx_equals(&srcs, &mirror->srcs)
        && hmapx_equals(&dsts, &mirror->dsts)
        && vlan_bitmap_equal(mirror->vlans, s->src_vlans)
        && mirror->out == out
        && mirror->out_vlan == out_vlan)
    {
        hmapx_destroy(&srcs);
        hmapx_destroy(&dsts);
        return 0;
    }

    hmapx_swap(&srcs, &mirror->srcs);
    hmapx_destroy(&srcs);

    hmapx_swap(&dsts, &mirror->dsts);
    hmapx_destroy(&dsts);

    free(mirror->vlans);
    mirror->vlans = vlan_bitmap_clone(s->src_vlans);

    mirror->out = out;
    mirror->out_vlan = out_vlan;

    /* Update bundles. */
    mirror_bit = MIRROR_MASK_C(1) << mirror->idx;
    HMAP_FOR_EACH (bundle, hmap_node, &mirror->ofproto->bundles) {
        if (hmapx_contains(&mirror->srcs, bundle)) {
            bundle->src_mirrors |= mirror_bit;
        } else {
            bundle->src_mirrors &= ~mirror_bit;
        }

        if (hmapx_contains(&mirror->dsts, bundle)) {
            bundle->dst_mirrors |= mirror_bit;
        } else {
            bundle->dst_mirrors &= ~mirror_bit;
        }

        if (mirror->out == bundle) {
            bundle->mirror_out |= mirror_bit;
        } else {
            bundle->mirror_out &= ~mirror_bit;
        }
    }

    ofproto->need_revalidate = true;
    mac_learning_flush(ofproto->ml);

    return 0;
}

static void
mirror_destroy(struct ofmirror *mirror)
{
    struct ofproto_dpif *ofproto;
    mirror_mask_t mirror_bit;
    struct ofbundle *bundle;

    if (!mirror) {
        return;
    }

    ofproto = mirror->ofproto;
    ofproto->need_revalidate = true;
    mac_learning_flush(ofproto->ml);

    mirror_bit = MIRROR_MASK_C(1) << mirror->idx;
    HMAP_FOR_EACH (bundle, hmap_node, &ofproto->bundles) {
        bundle->src_mirrors &= ~mirror_bit;
        bundle->dst_mirrors &= ~mirror_bit;
        bundle->mirror_out &= ~mirror_bit;
    }

    hmapx_destroy(&mirror->srcs);
    hmapx_destroy(&mirror->dsts);
    free(mirror->vlans);

    ofproto->mirrors[mirror->idx] = NULL;
    free(mirror->name);
    free(mirror);
}

static int
set_flood_vlans(struct ofproto *ofproto_, unsigned long *flood_vlans)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    if (mac_learning_set_flood_vlans(ofproto->ml, flood_vlans)) {
        ofproto->need_revalidate = true;
        mac_learning_flush(ofproto->ml);
    }
    return 0;
}

static bool
is_mirror_output_bundle(struct ofproto *ofproto_, void *aux)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct ofbundle *bundle = bundle_lookup(ofproto, aux);
    return bundle && bundle->mirror_out != 0;
}

/* Ports. */

static struct ofport_dpif *
get_ofp_port(struct ofproto_dpif *ofproto, uint16_t ofp_port)
{
    struct ofport *ofport = ofproto_get_port(&ofproto->up, ofp_port);
    return ofport ? ofport_dpif_cast(ofport) : NULL;
}

static struct ofport_dpif *
get_odp_port(struct ofproto_dpif *ofproto, uint32_t odp_port)
{
    return get_ofp_port(ofproto, odp_port_to_ofp_port(odp_port));
}

static void
ofproto_port_from_dpif_port(struct ofproto_port *ofproto_port,
                            struct dpif_port *dpif_port)
{
    ofproto_port->name = dpif_port->name;
    ofproto_port->type = dpif_port->type;
    ofproto_port->ofp_port = odp_port_to_ofp_port(dpif_port->port_no);
}

static void
port_run(struct ofport_dpif *ofport)
{
    if (ofport->cfm) {
        cfm_run(ofport->cfm);

        if (cfm_should_send_ccm(ofport->cfm)) {
            struct ofpbuf packet;
            struct ccm *ccm;

            ofpbuf_init(&packet, 0);
            ccm = eth_compose(&packet, eth_addr_ccm, ofport->up.opp.hw_addr,
                              ETH_TYPE_CFM, sizeof *ccm);
            cfm_compose_ccm(ofport->cfm, ccm);
            send_packet(ofproto_dpif_cast(ofport->up.ofproto),
                        ofport->odp_port, &packet);
            ofpbuf_uninit(&packet);
        }
    }
}

static void
port_wait(struct ofport_dpif *ofport)
{
    if (ofport->cfm) {
        cfm_wait(ofport->cfm);
    }
}

static int
port_query_by_name(const struct ofproto *ofproto_, const char *devname,
                   struct ofproto_port *ofproto_port)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct dpif_port dpif_port;
    int error;

    error = dpif_port_query_by_name(ofproto->dpif, devname, &dpif_port);
    if (!error) {
        ofproto_port_from_dpif_port(ofproto_port, &dpif_port);
    }
    return error;
}

static int
port_add(struct ofproto *ofproto_, struct netdev *netdev, uint16_t *ofp_portp)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    uint16_t odp_port;
    int error;

    error = dpif_port_add(ofproto->dpif, netdev, &odp_port);
    if (!error) {
        *ofp_portp = odp_port_to_ofp_port(odp_port);
    }
    return error;
}

static int
port_del(struct ofproto *ofproto_, uint16_t ofp_port)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    int error;

    error = dpif_port_del(ofproto->dpif, ofp_port_to_odp_port(ofp_port));
    if (!error) {
        struct ofport_dpif *ofport = get_ofp_port(ofproto, ofp_port);
        if (ofport) {
            /* The caller is going to close ofport->up.netdev.  If this is a
             * bonded port, then the bond is using that netdev, so remove it
             * from the bond.  The client will need to reconfigure everything
             * after deleting ports, so then the slave will get re-added. */
            bundle_remove(&ofport->up);
        }
    }
    return error;
}

struct port_dump_state {
    struct dpif_port_dump dump;
    bool done;
};

static int
port_dump_start(const struct ofproto *ofproto_, void **statep)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    struct port_dump_state *state;

    *statep = state = xmalloc(sizeof *state);
    dpif_port_dump_start(&state->dump, ofproto->dpif);
    state->done = false;
    return 0;
}

static int
port_dump_next(const struct ofproto *ofproto_ OVS_UNUSED, void *state_,
               struct ofproto_port *port)
{
    struct port_dump_state *state = state_;
    struct dpif_port dpif_port;

    if (dpif_port_dump_next(&state->dump, &dpif_port)) {
        ofproto_port_from_dpif_port(port, &dpif_port);
        return 0;
    } else {
        int error = dpif_port_dump_done(&state->dump);
        state->done = true;
        return error ? error : EOF;
    }
}

static int
port_dump_done(const struct ofproto *ofproto_ OVS_UNUSED, void *state_)
{
    struct port_dump_state *state = state_;

    if (!state->done) {
        dpif_port_dump_done(&state->dump);
    }
    free(state);
    return 0;
}

static int
port_poll(const struct ofproto *ofproto_, char **devnamep)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    return dpif_port_poll(ofproto->dpif, devnamep);
}

static void
port_poll_wait(const struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    dpif_port_poll_wait(ofproto->dpif);
}

static int
port_is_lacp_current(const struct ofport *ofport_)
{
    const struct ofport_dpif *ofport = ofport_dpif_cast(ofport_);
    return (ofport->bundle && ofport->bundle->lacp
            ? lacp_slave_is_current(ofport->bundle->lacp, ofport)
            : -1);
}

/* Upcall handling. */

/* Given 'upcall', of type DPIF_UC_ACTION or DPIF_UC_MISS, sends an
 * OFPT_PACKET_IN message to each OpenFlow controller as necessary according to
 * their individual configurations.
 *
 * If 'clone' is true, the caller retains ownership of 'upcall->packet'.
 * Otherwise, ownership is transferred to this function. */
static void
send_packet_in(struct ofproto_dpif *ofproto, struct dpif_upcall *upcall,
               const struct flow *flow, bool clone)
{
    struct ofputil_packet_in pin;

    pin.packet = upcall->packet;
    pin.in_port = flow->in_port;
    pin.reason = upcall->type == DPIF_UC_MISS ? OFPR_NO_MATCH : OFPR_ACTION;
    pin.buffer_id = 0;          /* not yet known */
    pin.send_len = upcall->userdata;
    connmgr_send_packet_in(ofproto->up.connmgr, &pin, flow,
                           clone ? NULL : upcall->packet);
}

static bool
process_special(struct ofproto_dpif *ofproto, const struct flow *flow,
                const struct ofpbuf *packet)
{
    if (cfm_should_process_flow(flow)) {
        struct ofport_dpif *ofport = get_ofp_port(ofproto, flow->in_port);
        if (ofport && ofport->cfm) {
            cfm_process_heartbeat(ofport->cfm, packet);
        }
        return true;
    } else if (flow->dl_type == htons(ETH_TYPE_LACP)) {
        struct ofport_dpif *port = get_ofp_port(ofproto, flow->in_port);
        if (port && port->bundle && port->bundle->lacp) {
            const struct lacp_pdu *pdu = parse_lacp_packet(packet);
            if (pdu) {
                lacp_process_pdu(port->bundle->lacp, port, pdu);
            }
            return true;
        }
    }
    return false;
}

static void
handle_miss_upcall(struct ofproto_dpif *ofproto, struct dpif_upcall *upcall)
{
    struct facet *facet;
    struct flow flow;

    /* Obtain in_port and tun_id, at least. */
    odp_flow_key_to_flow(upcall->key, upcall->key_len, &flow);

    /* Set header pointers in 'flow'. */
    flow_extract(upcall->packet, flow.tun_id, flow.in_port, &flow);

    /* Handle 802.1ag and LACP. */
    if (process_special(ofproto, &flow, upcall->packet)) {
        ofpbuf_delete(upcall->packet);
        ofproto->n_matches++;
        return;
    }

    /* Check with in-band control to see if this packet should be sent
     * to the local port regardless of the flow table. */
    if (connmgr_msg_in_hook(ofproto->up.connmgr, &flow, upcall->packet)) {
        send_packet(ofproto, OFPP_LOCAL, upcall->packet);
    }

    facet = facet_lookup_valid(ofproto, &flow);
    if (!facet) {
        struct rule_dpif *rule = rule_dpif_lookup(ofproto, &flow);
        if (!rule) {
            /* Don't send a packet-in if OFPPC_NO_PACKET_IN asserted. */
            struct ofport_dpif *port = get_ofp_port(ofproto, flow.in_port);
            if (port) {
                if (port->up.opp.config & htonl(OFPPC_NO_PACKET_IN)) {
                    COVERAGE_INC(ofproto_dpif_no_packet_in);
                    /* XXX install 'drop' flow entry */
                    ofpbuf_delete(upcall->packet);
                    return;
                }
            } else {
                VLOG_WARN_RL(&rl, "packet-in on unknown port %"PRIu16,
                             flow.in_port);
            }

            send_packet_in(ofproto, upcall, &flow, false);
            return;
        }

        facet = facet_create(rule, &flow, upcall->packet);
    } else if (!facet->may_install) {
        /* The facet is not installable, that is, we need to process every
         * packet, so process the current packet's actions into 'facet'. */
        facet_make_actions(ofproto, facet, upcall->packet);
    }

    if (facet->rule->up.cr.priority == FAIL_OPEN_PRIORITY) {
        /*
         * Extra-special case for fail-open mode.
         *
         * We are in fail-open mode and the packet matched the fail-open rule,
         * but we are connected to a controller too.  We should send the packet
         * up to the controller in the hope that it will try to set up a flow
         * and thereby allow us to exit fail-open.
         *
         * See the top-level comment in fail-open.c for more information.
         */
        send_packet_in(ofproto, upcall, &flow, true);
    }

    facet_execute(ofproto, facet, upcall->packet);
    facet_install(ofproto, facet, false);
    ofproto->n_matches++;
}

static void
handle_upcall(struct ofproto_dpif *ofproto, struct dpif_upcall *upcall)
{
    struct flow flow;

    switch (upcall->type) {
    case DPIF_UC_ACTION:
        COVERAGE_INC(ofproto_dpif_ctlr_action);
        odp_flow_key_to_flow(upcall->key, upcall->key_len, &flow);
        send_packet_in(ofproto, upcall, &flow, false);
        break;

    case DPIF_UC_SAMPLE:
        if (ofproto->sflow) {
            odp_flow_key_to_flow(upcall->key, upcall->key_len, &flow);
            ofproto_sflow_received(ofproto->sflow, upcall, &flow);
        }
        ofpbuf_delete(upcall->packet);
        break;

    case DPIF_UC_MISS:
        handle_miss_upcall(ofproto, upcall);
        break;

    case DPIF_N_UC_TYPES:
    default:
        VLOG_WARN_RL(&rl, "upcall has unexpected type %"PRIu32, upcall->type);
        break;
    }
}

/* Flow expiration. */

static int facet_max_idle(const struct ofproto_dpif *);
static void update_stats(struct ofproto_dpif *);
static void rule_expire(struct rule_dpif *);
static void expire_facets(struct ofproto_dpif *, int dp_max_idle);

/* This function is called periodically by run().  Its job is to collect
 * updates for the flows that have been installed into the datapath, most
 * importantly when they last were used, and then use that information to
 * expire flows that have not been used recently.
 *
 * Returns the number of milliseconds after which it should be called again. */
static int
expire(struct ofproto_dpif *ofproto)
{
    struct rule_dpif *rule, *next_rule;
    struct cls_cursor cursor;
    int dp_max_idle;

    /* Update stats for each flow in the datapath. */
    update_stats(ofproto);

    /* Expire facets that have been idle too long. */
    dp_max_idle = facet_max_idle(ofproto);
    expire_facets(ofproto, dp_max_idle);

    /* Expire OpenFlow flows whose idle_timeout or hard_timeout has passed. */
    cls_cursor_init(&cursor, &ofproto->up.tables[0], NULL);
    CLS_CURSOR_FOR_EACH_SAFE (rule, next_rule, up.cr, &cursor) {
        rule_expire(rule);
    }

    /* All outstanding data in existing flows has been accounted, so it's a
     * good time to do bond rebalancing. */
    if (ofproto->has_bonded_bundles) {
        struct ofbundle *bundle;

        HMAP_FOR_EACH (bundle, hmap_node, &ofproto->bundles) {
            if (bundle->bond) {
                bond_rebalance(bundle->bond, &ofproto->revalidate_set);
            }
        }
    }

    return MIN(dp_max_idle, 1000);
}

/* Update 'packet_count', 'byte_count', and 'used' members of installed facets.
 *
 * This function also pushes statistics updates to rules which each facet
 * resubmits into.  Generally these statistics will be accurate.  However, if a
 * facet changes the rule it resubmits into at some time in between
 * update_stats() runs, it is possible that statistics accrued to the
 * old rule will be incorrectly attributed to the new rule.  This could be
 * avoided by calling update_stats() whenever rules are created or
 * deleted.  However, the performance impact of making so many calls to the
 * datapath do not justify the benefit of having perfectly accurate statistics.
 */
static void
update_stats(struct ofproto_dpif *p)
{
    const struct dpif_flow_stats *stats;
    struct dpif_flow_dump dump;
    const struct nlattr *key;
    size_t key_len;

    dpif_flow_dump_start(&dump, p->dpif);
    while (dpif_flow_dump_next(&dump, &key, &key_len, NULL, NULL, &stats)) {
        struct facet *facet;
        struct flow flow;

        if (odp_flow_key_to_flow(key, key_len, &flow)) {
            struct ds s;

            ds_init(&s);
            odp_flow_key_format(key, key_len, &s);
            VLOG_WARN_RL(&rl, "failed to convert ODP flow key to flow: %s",
                         ds_cstr(&s));
            ds_destroy(&s);

            continue;
        }
        facet = facet_find(p, &flow);

        if (facet && facet->installed) {

            if (stats->n_packets >= facet->dp_packet_count) {
                uint64_t extra = stats->n_packets - facet->dp_packet_count;
                facet->packet_count += extra;
            } else {
                VLOG_WARN_RL(&rl, "unexpected packet count from the datapath");
            }

            if (stats->n_bytes >= facet->dp_byte_count) {
                facet->byte_count += stats->n_bytes - facet->dp_byte_count;
            } else {
                VLOG_WARN_RL(&rl, "unexpected byte count from datapath");
            }

            facet->dp_packet_count = stats->n_packets;
            facet->dp_byte_count = stats->n_bytes;

            facet_update_time(p, facet, stats->used);
            facet_account(p, facet, stats->n_bytes);
            facet_push_stats(facet);
        } else {
            /* There's a flow in the datapath that we know nothing about.
             * Delete it. */
            COVERAGE_INC(facet_unexpected);
            dpif_flow_del(p->dpif, key, key_len, NULL);
        }
    }
    dpif_flow_dump_done(&dump);
}

/* Calculates and returns the number of milliseconds of idle time after which
 * facets should expire from the datapath and we should fold their statistics
 * into their parent rules in userspace. */
static int
facet_max_idle(const struct ofproto_dpif *ofproto)
{
    /*
     * Idle time histogram.
     *
     * Most of the time a switch has a relatively small number of facets.  When
     * this is the case we might as well keep statistics for all of them in
     * userspace and to cache them in the kernel datapath for performance as
     * well.
     *
     * As the number of facets increases, the memory required to maintain
     * statistics about them in userspace and in the kernel becomes
     * significant.  However, with a large number of facets it is likely that
     * only a few of them are "heavy hitters" that consume a large amount of
     * bandwidth.  At this point, only heavy hitters are worth caching in the
     * kernel and maintaining in userspaces; other facets we can discard.
     *
     * The technique used to compute the idle time is to build a histogram with
     * N_BUCKETS buckets whose width is BUCKET_WIDTH msecs each.  Each facet
     * that is installed in the kernel gets dropped in the appropriate bucket.
     * After the histogram has been built, we compute the cutoff so that only
     * the most-recently-used 1% of facets (but at least 1000 flows) are kept
     * cached.  At least the most-recently-used bucket of facets is kept, so
     * actually an arbitrary number of facets can be kept in any given
     * expiration run (though the next run will delete most of those unless
     * they receive additional data).
     *
     * This requires a second pass through the facets, in addition to the pass
     * made by update_stats(), because the former function never looks
     * at uninstallable facets.
     */
    enum { BUCKET_WIDTH = ROUND_UP(100, TIME_UPDATE_INTERVAL) };
    enum { N_BUCKETS = 5000 / BUCKET_WIDTH };
    int buckets[N_BUCKETS] = { 0 };
    struct facet *facet;
    int total, bucket;
    long long int now;
    int i;

    total = hmap_count(&ofproto->facets);
    if (total <= 1000) {
        return N_BUCKETS * BUCKET_WIDTH;
    }

    /* Build histogram. */
    now = time_msec();
    HMAP_FOR_EACH (facet, hmap_node, &ofproto->facets) {
        long long int idle = now - facet->used;
        int bucket = (idle <= 0 ? 0
                      : idle >= BUCKET_WIDTH * N_BUCKETS ? N_BUCKETS - 1
                      : (unsigned int) idle / BUCKET_WIDTH);
        buckets[bucket]++;
    }

    /* Find the first bucket whose flows should be expired. */
    for (bucket = 0; bucket < N_BUCKETS; bucket++) {
        if (buckets[bucket]) {
            int subtotal = 0;
            do {
                subtotal += buckets[bucket++];
            } while (bucket < N_BUCKETS && subtotal < MAX(1000, total / 100));
            break;
        }
    }

    if (VLOG_IS_DBG_ENABLED()) {
        struct ds s;

        ds_init(&s);
        ds_put_cstr(&s, "keep");
        for (i = 0; i < N_BUCKETS; i++) {
            if (i == bucket) {
                ds_put_cstr(&s, ", drop");
            }
            if (buckets[i]) {
                ds_put_format(&s, " %d:%d", i * BUCKET_WIDTH, buckets[i]);
            }
        }
        VLOG_INFO("%s: %s (msec:count)", ofproto->up.name, ds_cstr(&s));
        ds_destroy(&s);
    }

    return bucket * BUCKET_WIDTH;
}

static void
facet_active_timeout(struct ofproto_dpif *ofproto, struct facet *facet)
{
    if (ofproto->netflow && !facet_is_controller_flow(facet) &&
        netflow_active_timeout_expired(ofproto->netflow, &facet->nf_flow)) {
        struct ofexpired expired;

        if (facet->installed) {
            struct dpif_flow_stats stats;

            facet_put__(ofproto, facet, facet->actions, facet->actions_len,
                        &stats);
            facet_update_stats(ofproto, facet, &stats);
        }

        expired.flow = facet->flow;
        expired.packet_count = facet->packet_count;
        expired.byte_count = facet->byte_count;
        expired.used = facet->used;
        netflow_expire(ofproto->netflow, &facet->nf_flow, &expired);
    }
}

static void
expire_facets(struct ofproto_dpif *ofproto, int dp_max_idle)
{
    long long int cutoff = time_msec() - dp_max_idle;
    struct facet *facet, *next_facet;

    HMAP_FOR_EACH_SAFE (facet, next_facet, hmap_node, &ofproto->facets) {
        facet_active_timeout(ofproto, facet);
        if (facet->used < cutoff) {
            facet_remove(ofproto, facet);
        }
    }
}

/* If 'rule' is an OpenFlow rule, that has expired according to OpenFlow rules,
 * then delete it entirely. */
static void
rule_expire(struct rule_dpif *rule)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    struct facet *facet, *next_facet;
    long long int now;
    uint8_t reason;

    /* Has 'rule' expired? */
    now = time_msec();
    if (rule->up.hard_timeout
        && now > rule->up.created + rule->up.hard_timeout * 1000) {
        reason = OFPRR_HARD_TIMEOUT;
    } else if (rule->up.idle_timeout && list_is_empty(&rule->facets)
               && now > rule->used + rule->up.idle_timeout * 1000) {
        reason = OFPRR_IDLE_TIMEOUT;
    } else {
        return;
    }

    COVERAGE_INC(ofproto_dpif_expired);

    /* Update stats.  (This is a no-op if the rule expired due to an idle
     * timeout, because that only happens when the rule has no facets left.) */
    LIST_FOR_EACH_SAFE (facet, next_facet, list_node, &rule->facets) {
        facet_remove(ofproto, facet);
    }

    /* Get rid of the rule. */
    ofproto_rule_expire(&rule->up, reason);
}

/* Facets. */

/* Creates and returns a new facet owned by 'rule', given a 'flow' and an
 * example 'packet' within that flow.
 *
 * The caller must already have determined that no facet with an identical
 * 'flow' exists in 'ofproto' and that 'flow' is the best match for 'rule' in
 * the ofproto's classifier table. */
static struct facet *
facet_create(struct rule_dpif *rule, const struct flow *flow,
             const struct ofpbuf *packet)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    struct facet *facet;

    facet = xzalloc(sizeof *facet);
    facet->used = time_msec();
    hmap_insert(&ofproto->facets, &facet->hmap_node, flow_hash(flow, 0));
    list_push_back(&rule->facets, &facet->list_node);
    facet->rule = rule;
    facet->flow = *flow;
    netflow_flow_init(&facet->nf_flow);
    netflow_flow_update_time(ofproto->netflow, &facet->nf_flow, facet->used);

    facet_make_actions(ofproto, facet, packet);

    return facet;
}

static void
facet_free(struct facet *facet)
{
    free(facet->actions);
    free(facet);
}

/* Executes, within 'ofproto', the 'n_actions' actions in 'actions' on
 * 'packet', which arrived on 'in_port'.
 *
 * Takes ownership of 'packet'. */
static bool
execute_odp_actions(struct ofproto_dpif *ofproto, const struct flow *flow,
                    const struct nlattr *odp_actions, size_t actions_len,
                    struct ofpbuf *packet)
{
    if (actions_len == NLA_ALIGN(NLA_HDRLEN + sizeof(uint64_t))
        && odp_actions->nla_type == ODP_ACTION_ATTR_CONTROLLER) {
        /* As an optimization, avoid a round-trip from userspace to kernel to
         * userspace.  This also avoids possibly filling up kernel packet
         * buffers along the way. */
        struct dpif_upcall upcall;

        upcall.type = DPIF_UC_ACTION;
        upcall.packet = packet;
        upcall.key = NULL;
        upcall.key_len = 0;
        upcall.userdata = nl_attr_get_u64(odp_actions);
        upcall.sample_pool = 0;
        upcall.actions = NULL;
        upcall.actions_len = 0;

        send_packet_in(ofproto, &upcall, flow, false);

        return true;
    } else {
        int error;

        error = dpif_execute(ofproto->dpif, odp_actions, actions_len, packet);
        ofpbuf_delete(packet);
        return !error;
    }
}

/* Executes the actions indicated by 'facet' on 'packet' and credits 'facet''s
 * statistics appropriately.  'packet' must have at least sizeof(struct
 * ofp_packet_in) bytes of headroom.
 *
 * For correct results, 'packet' must actually be in 'facet''s flow; that is,
 * applying flow_extract() to 'packet' would yield the same flow as
 * 'facet->flow'.
 *
 * 'facet' must have accurately composed ODP actions; that is, it must not be
 * in need of revalidation.
 *
 * Takes ownership of 'packet'. */
static void
facet_execute(struct ofproto_dpif *ofproto, struct facet *facet,
              struct ofpbuf *packet)
{
    struct dpif_flow_stats stats;

    assert(ofpbuf_headroom(packet) >= sizeof(struct ofp_packet_in));

    flow_extract_stats(&facet->flow, packet, &stats);
    stats.used = time_msec();
    if (execute_odp_actions(ofproto, &facet->flow,
                            facet->actions, facet->actions_len, packet)) {
        facet_update_stats(ofproto, facet, &stats);
    }
}

/* Remove 'facet' from 'ofproto' and free up the associated memory:
 *
 *   - If 'facet' was installed in the datapath, uninstalls it and updates its
 *     rule's statistics, via facet_uninstall().
 *
 *   - Removes 'facet' from its rule and from ofproto->facets.
 */
static void
facet_remove(struct ofproto_dpif *ofproto, struct facet *facet)
{
    facet_uninstall(ofproto, facet);
    facet_flush_stats(ofproto, facet);
    hmap_remove(&ofproto->facets, &facet->hmap_node);
    list_remove(&facet->list_node);
    facet_free(facet);
}

/* Composes the ODP actions for 'facet' based on its rule's actions. */
static void
facet_make_actions(struct ofproto_dpif *p, struct facet *facet,
                   const struct ofpbuf *packet)
{
    const struct rule_dpif *rule = facet->rule;
    struct ofpbuf *odp_actions;
    struct action_xlate_ctx ctx;

    action_xlate_ctx_init(&ctx, p, &facet->flow, packet);
    odp_actions = xlate_actions(&ctx, rule->up.actions, rule->up.n_actions);
    facet->tags = ctx.tags;
    facet->may_install = ctx.may_set_up_flow;
    facet->nf_flow.output_iface = ctx.nf_output_iface;

    if (facet->actions_len != odp_actions->size
        || memcmp(facet->actions, odp_actions->data, odp_actions->size)) {
        free(facet->actions);
        facet->actions_len = odp_actions->size;
        facet->actions = xmemdup(odp_actions->data, odp_actions->size);
    }

    ofpbuf_delete(odp_actions);
}

static int
facet_put__(struct ofproto_dpif *ofproto, struct facet *facet,
            const struct nlattr *actions, size_t actions_len,
            struct dpif_flow_stats *stats)
{
    struct odputil_keybuf keybuf;
    enum dpif_flow_put_flags flags;
    struct ofpbuf key;

    flags = DPIF_FP_CREATE | DPIF_FP_MODIFY;
    if (stats) {
        flags |= DPIF_FP_ZERO_STATS;
        facet->dp_packet_count = 0;
        facet->dp_byte_count = 0;
    }

    ofpbuf_use_stack(&key, &keybuf, sizeof keybuf);
    odp_flow_key_from_flow(&key, &facet->flow);

    return dpif_flow_put(ofproto->dpif, flags, key.data, key.size,
                         actions, actions_len, stats);
}

/* If 'facet' is installable, inserts or re-inserts it into 'p''s datapath.  If
 * 'zero_stats' is true, clears any existing statistics from the datapath for
 * 'facet'. */
static void
facet_install(struct ofproto_dpif *p, struct facet *facet, bool zero_stats)
{
    struct dpif_flow_stats stats;

    if (facet->may_install
        && !facet_put__(p, facet, facet->actions, facet->actions_len,
                        zero_stats ? &stats : NULL)) {
        facet->installed = true;
    }
}

static void
facet_account(struct ofproto_dpif *ofproto,
              struct facet *facet, uint64_t extra_bytes)
{
    uint64_t total_bytes, n_bytes;
    struct ofbundle *in_bundle;
    const struct nlattr *a;
    tag_type dummy = 0;
    unsigned int left;
    int vlan;

    total_bytes = facet->byte_count + extra_bytes;
    if (total_bytes <= facet->accounted_bytes) {
        return;
    }
    n_bytes = total_bytes - facet->accounted_bytes;
    facet->accounted_bytes = total_bytes;

    /* Test that 'tags' is nonzero to ensure that only flows that include an
     * OFPP_NORMAL action are used for learning and bond slave rebalancing.
     * This works because OFPP_NORMAL always sets a nonzero tag value.
     *
     * Feed information from the active flows back into the learning table to
     * ensure that table is always in sync with what is actually flowing
     * through the datapath. */
    if (!facet->tags
        || !is_admissible(ofproto, &facet->flow, false, &dummy,
                          &vlan, &in_bundle)) {
        return;
    }

    update_learning_table(ofproto, &facet->flow, vlan, in_bundle);

    if (!ofproto->has_bonded_bundles) {
        return;
    }
    NL_ATTR_FOR_EACH_UNSAFE (a, left, facet->actions, facet->actions_len) {
        if (nl_attr_type(a) == ODP_ACTION_ATTR_OUTPUT) {
            struct ofport_dpif *port;

            port = get_odp_port(ofproto, nl_attr_get_u32(a));
            if (port && port->bundle && port->bundle->bond) {
                bond_account(port->bundle->bond, &facet->flow, vlan, n_bytes);
            }
        }
    }
}

/* If 'rule' is installed in the datapath, uninstalls it. */
static void
facet_uninstall(struct ofproto_dpif *p, struct facet *facet)
{
    if (facet->installed) {
        struct odputil_keybuf keybuf;
        struct dpif_flow_stats stats;
        struct ofpbuf key;

        ofpbuf_use_stack(&key, &keybuf, sizeof keybuf);
        odp_flow_key_from_flow(&key, &facet->flow);

        if (!dpif_flow_del(p->dpif, key.data, key.size, &stats)) {
            facet_update_stats(p, facet, &stats);
        }
        facet->installed = false;
        facet->dp_packet_count = 0;
        facet->dp_byte_count = 0;
    } else {
        assert(facet->dp_packet_count == 0);
        assert(facet->dp_byte_count == 0);
    }
}

/* Returns true if the only action for 'facet' is to send to the controller.
 * (We don't report NetFlow expiration messages for such facets because they
 * are just part of the control logic for the network, not real traffic). */
static bool
facet_is_controller_flow(struct facet *facet)
{
    return (facet
            && facet->rule->up.n_actions == 1
            && action_outputs_to_port(&facet->rule->up.actions[0],
                                      htons(OFPP_CONTROLLER)));
}

/* Folds all of 'facet''s statistics into its rule.  Also updates the
 * accounting ofhook and emits a NetFlow expiration if appropriate.  All of
 * 'facet''s statistics in the datapath should have been zeroed and folded into
 * its packet and byte counts before this function is called. */
static void
facet_flush_stats(struct ofproto_dpif *ofproto, struct facet *facet)
{
    assert(!facet->dp_byte_count);
    assert(!facet->dp_packet_count);

    facet_push_stats(facet);
    facet_account(ofproto, facet, 0);

    if (ofproto->netflow && !facet_is_controller_flow(facet)) {
        struct ofexpired expired;
        expired.flow = facet->flow;
        expired.packet_count = facet->packet_count;
        expired.byte_count = facet->byte_count;
        expired.used = facet->used;
        netflow_expire(ofproto->netflow, &facet->nf_flow, &expired);
    }

    facet->rule->packet_count += facet->packet_count;
    facet->rule->byte_count += facet->byte_count;

    /* Reset counters to prevent double counting if 'facet' ever gets
     * reinstalled. */
    facet->packet_count = 0;
    facet->byte_count = 0;
    facet->rs_packet_count = 0;
    facet->rs_byte_count = 0;
    facet->accounted_bytes = 0;

    netflow_flow_clear(&facet->nf_flow);
}

/* Searches 'ofproto''s table of facets for one exactly equal to 'flow'.
 * Returns it if found, otherwise a null pointer.
 *
 * The returned facet might need revalidation; use facet_lookup_valid()
 * instead if that is important. */
static struct facet *
facet_find(struct ofproto_dpif *ofproto, const struct flow *flow)
{
    struct facet *facet;

    HMAP_FOR_EACH_WITH_HASH (facet, hmap_node, flow_hash(flow, 0),
                             &ofproto->facets) {
        if (flow_equal(flow, &facet->flow)) {
            return facet;
        }
    }

    return NULL;
}

/* Searches 'ofproto''s table of facets for one exactly equal to 'flow'.
 * Returns it if found, otherwise a null pointer.
 *
 * The returned facet is guaranteed to be valid. */
static struct facet *
facet_lookup_valid(struct ofproto_dpif *ofproto, const struct flow *flow)
{
    struct facet *facet = facet_find(ofproto, flow);

    /* The facet we found might not be valid, since we could be in need of
     * revalidation.  If it is not valid, don't return it. */
    if (facet
        && ofproto->need_revalidate
        && !facet_revalidate(ofproto, facet)) {
        COVERAGE_INC(facet_invalidated);
        return NULL;
    }

    return facet;
}

/* Re-searches 'ofproto''s classifier for a rule matching 'facet':
 *
 *   - If the rule found is different from 'facet''s current rule, moves
 *     'facet' to the new rule and recompiles its actions.
 *
 *   - If the rule found is the same as 'facet''s current rule, leaves 'facet'
 *     where it is and recompiles its actions anyway.
 *
 *   - If there is none, destroys 'facet'.
 *
 * Returns true if 'facet' still exists, false if it has been destroyed. */
static bool
facet_revalidate(struct ofproto_dpif *ofproto, struct facet *facet)
{
    struct action_xlate_ctx ctx;
    struct ofpbuf *odp_actions;
    struct rule_dpif *new_rule;
    bool actions_changed;

    COVERAGE_INC(facet_revalidate);

    /* Determine the new rule. */
    new_rule = rule_dpif_lookup(ofproto, &facet->flow);
    if (!new_rule) {
        /* No new rule, so delete the facet. */
        facet_remove(ofproto, facet);
        return false;
    }

    /* Calculate new ODP actions.
     *
     * We do not modify any 'facet' state yet, because we might need to, e.g.,
     * emit a NetFlow expiration and, if so, we need to have the old state
     * around to properly compose it. */
    action_xlate_ctx_init(&ctx, ofproto, &facet->flow, NULL);
    odp_actions = xlate_actions(&ctx,
                                new_rule->up.actions, new_rule->up.n_actions);
    actions_changed = (facet->actions_len != odp_actions->size
                       || memcmp(facet->actions, odp_actions->data,
                                 facet->actions_len));

    /* If the ODP actions changed or the installability changed, then we need
     * to talk to the datapath. */
    if (actions_changed || ctx.may_set_up_flow != facet->installed) {
        if (ctx.may_set_up_flow) {
            struct dpif_flow_stats stats;

            facet_put__(ofproto, facet,
                        odp_actions->data, odp_actions->size, &stats);
            facet_update_stats(ofproto, facet, &stats);
        } else {
            facet_uninstall(ofproto, facet);
        }

        /* The datapath flow is gone or has zeroed stats, so push stats out of
         * 'facet' into 'rule'. */
        facet_flush_stats(ofproto, facet);
    }

    /* Update 'facet' now that we've taken care of all the old state. */
    facet->tags = ctx.tags;
    facet->nf_flow.output_iface = ctx.nf_output_iface;
    facet->may_install = ctx.may_set_up_flow;
    if (actions_changed) {
        free(facet->actions);
        facet->actions_len = odp_actions->size;
        facet->actions = xmemdup(odp_actions->data, odp_actions->size);
    }
    if (facet->rule != new_rule) {
        COVERAGE_INC(facet_changed_rule);
        list_remove(&facet->list_node);
        list_push_back(&new_rule->facets, &facet->list_node);
        facet->rule = new_rule;
        facet->used = new_rule->up.created;
        facet->rs_used = facet->used;
    }

    ofpbuf_delete(odp_actions);

    return true;
}

/* Updates 'facet''s used time.  Caller is responsible for calling
 * facet_push_stats() to update the flows which 'facet' resubmits into. */
static void
facet_update_time(struct ofproto_dpif *ofproto, struct facet *facet,
                  long long int used)
{
    if (used > facet->used) {
        facet->used = used;
        if (used > facet->rule->used) {
            facet->rule->used = used;
        }
        netflow_flow_update_time(ofproto->netflow, &facet->nf_flow, used);
    }
}

/* Folds the statistics from 'stats' into the counters in 'facet'.
 *
 * Because of the meaning of a facet's counters, it only makes sense to do this
 * if 'stats' are not tracked in the datapath, that is, if 'stats' represents a
 * packet that was sent by hand or if it represents statistics that have been
 * cleared out of the datapath. */
static void
facet_update_stats(struct ofproto_dpif *ofproto, struct facet *facet,
                   const struct dpif_flow_stats *stats)
{
    if (stats->n_packets || stats->used > facet->used) {
        facet_update_time(ofproto, facet, stats->used);
        facet->packet_count += stats->n_packets;
        facet->byte_count += stats->n_bytes;
        facet_push_stats(facet);
        netflow_flow_update_flags(&facet->nf_flow, stats->tcp_flags);
    }
}

static void
facet_push_stats(struct facet *facet)
{
    uint64_t rs_packets, rs_bytes;

    assert(facet->packet_count >= facet->rs_packet_count);
    assert(facet->byte_count >= facet->rs_byte_count);
    assert(facet->used >= facet->rs_used);

    rs_packets = facet->packet_count - facet->rs_packet_count;
    rs_bytes = facet->byte_count - facet->rs_byte_count;

    if (rs_packets || rs_bytes || facet->used > facet->rs_used) {
        facet->rs_packet_count = facet->packet_count;
        facet->rs_byte_count = facet->byte_count;
        facet->rs_used = facet->used;

        flow_push_stats(facet->rule, &facet->flow,
                        rs_packets, rs_bytes, facet->used);
    }
}

struct ofproto_push {
    struct action_xlate_ctx ctx;
    uint64_t packets;
    uint64_t bytes;
    long long int used;
};

static void
push_resubmit(struct action_xlate_ctx *ctx, struct rule_dpif *rule)
{
    struct ofproto_push *push = CONTAINER_OF(ctx, struct ofproto_push, ctx);

    if (rule) {
        rule->packet_count += push->packets;
        rule->byte_count += push->bytes;
        rule->used = MAX(push->used, rule->used);
    }
}

/* Pushes flow statistics to the rules which 'flow' resubmits into given
 * 'rule''s actions. */
static void
flow_push_stats(const struct rule_dpif *rule,
                struct flow *flow, uint64_t packets, uint64_t bytes,
                long long int used)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    struct ofproto_push push;

    push.packets = packets;
    push.bytes = bytes;
    push.used = used;

    action_xlate_ctx_init(&push.ctx, ofproto, flow, NULL);
    push.ctx.resubmit_hook = push_resubmit;
    ofpbuf_delete(xlate_actions(&push.ctx,
                                rule->up.actions, rule->up.n_actions));
}

/* Rules. */

static struct rule_dpif *
rule_dpif_lookup(struct ofproto_dpif *ofproto, const struct flow *flow)
{
    return rule_dpif_cast(rule_from_cls_rule(
                              classifier_lookup(&ofproto->up.tables[0],
                                                flow)));
}

static struct rule *
rule_alloc(void)
{
    struct rule_dpif *rule = xmalloc(sizeof *rule);
    return &rule->up;
}

static void
rule_dealloc(struct rule *rule_)
{
    struct rule_dpif *rule = rule_dpif_cast(rule_);
    free(rule);
}

static int
rule_construct(struct rule *rule_)
{
    struct rule_dpif *rule = rule_dpif_cast(rule_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    struct rule_dpif *old_rule;
    int error;

    error = validate_actions(rule->up.actions, rule->up.n_actions,
                             &rule->up.cr.flow, ofproto->max_ports);
    if (error) {
        return error;
    }

    old_rule = rule_dpif_cast(rule_from_cls_rule(classifier_find_rule_exactly(
                                                     &ofproto->up.tables[0],
                                                     &rule->up.cr)));
    if (old_rule) {
        ofproto_rule_destroy(&old_rule->up);
    }

    rule->used = rule->up.created;
    rule->packet_count = 0;
    rule->byte_count = 0;
    list_init(&rule->facets);
    classifier_insert(&ofproto->up.tables[0], &rule->up.cr);

    ofproto->need_revalidate = true;

    return 0;
}

static void
rule_destruct(struct rule *rule_)
{
    struct rule_dpif *rule = rule_dpif_cast(rule_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    struct facet *facet, *next_facet;

    classifier_remove(&ofproto->up.tables[0], &rule->up.cr);
    LIST_FOR_EACH_SAFE (facet, next_facet, list_node, &rule->facets) {
        facet_revalidate(ofproto, facet);
    }
    ofproto->need_revalidate = true;
}

static void
rule_get_stats(struct rule *rule_, uint64_t *packets, uint64_t *bytes)
{
    struct rule_dpif *rule = rule_dpif_cast(rule_);
    struct facet *facet;

    /* Start from historical data for 'rule' itself that are no longer tracked
     * in facets.  This counts, for example, facets that have expired. */
    *packets = rule->packet_count;
    *bytes = rule->byte_count;

    /* Add any statistics that are tracked by facets.  This includes
     * statistical data recently updated by ofproto_update_stats() as well as
     * stats for packets that were executed "by hand" via dpif_execute(). */
    LIST_FOR_EACH (facet, list_node, &rule->facets) {
        *packets += facet->packet_count;
        *bytes += facet->byte_count;
    }
}

static int
rule_execute(struct rule *rule_, struct flow *flow, struct ofpbuf *packet)
{
    struct rule_dpif *rule = rule_dpif_cast(rule_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    struct action_xlate_ctx ctx;
    struct ofpbuf *odp_actions;
    struct facet *facet;
    size_t size;

    /* First look for a related facet.  If we find one, account it to that. */
    facet = facet_lookup_valid(ofproto, flow);
    if (facet && facet->rule == rule) {
        facet_execute(ofproto, facet, packet);
        return 0;
    }

    /* Otherwise, if 'rule' is in fact the correct rule for 'packet', then
     * create a new facet for it and use that. */
    if (rule_dpif_lookup(ofproto, flow) == rule) {
        facet = facet_create(rule, flow, packet);
        facet_execute(ofproto, facet, packet);
        facet_install(ofproto, facet, true);
        return 0;
    }

    /* We can't account anything to a facet.  If we were to try, then that
     * facet would have a non-matching rule, busting our invariants. */
    action_xlate_ctx_init(&ctx, ofproto, flow, packet);
    odp_actions = xlate_actions(&ctx, rule->up.actions, rule->up.n_actions);
    size = packet->size;
    if (execute_odp_actions(ofproto, flow, odp_actions->data,
                            odp_actions->size, packet)) {
        rule->used = time_msec();
        rule->packet_count++;
        rule->byte_count += size;
        flow_push_stats(rule, flow, 1, size, rule->used);
    }
    ofpbuf_delete(odp_actions);

    return 0;
}

static int
rule_modify_actions(struct rule *rule_,
                    const union ofp_action *actions, size_t n_actions)
{
    struct rule_dpif *rule = rule_dpif_cast(rule_);
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(rule->up.ofproto);
    int error;

    error = validate_actions(actions, n_actions, &rule->up.cr.flow,
                             ofproto->max_ports);
    if (!error) {
        ofproto->need_revalidate = true;
    }
    return error;
}

/* Sends 'packet' out of port 'odp_port' within 'p'.
 * Returns 0 if successful, otherwise a positive errno value. */
static int
send_packet(struct ofproto_dpif *ofproto, uint32_t odp_port,
            const struct ofpbuf *packet)
{
    struct ofpbuf odp_actions;
    int error;

    ofpbuf_init(&odp_actions, 32);
    nl_msg_put_u32(&odp_actions, ODP_ACTION_ATTR_OUTPUT, odp_port);
    error = dpif_execute(ofproto->dpif, odp_actions.data, odp_actions.size,
                         packet);
    ofpbuf_uninit(&odp_actions);

    if (error) {
        VLOG_WARN_RL(&rl, "%s: failed to send packet on port %"PRIu32" (%s)",
                     ofproto->up.name, odp_port, strerror(error));
    }
    return error;
}

/* OpenFlow to ODP action translation. */

static void do_xlate_actions(const union ofp_action *in, size_t n_in,
                             struct action_xlate_ctx *ctx);
static bool xlate_normal(struct action_xlate_ctx *);

static void
add_output_action(struct action_xlate_ctx *ctx, uint16_t ofp_port)
{
    const struct ofport_dpif *ofport = get_ofp_port(ctx->ofproto, ofp_port);
    uint16_t odp_port = ofp_port_to_odp_port(ofp_port);

    if (ofport) {
        if (ofport->up.opp.config & htonl(OFPPC_NO_FWD)) {
            /* Forwarding disabled on port. */
            return;
        }
    } else {
        /*
         * We don't have an ofport record for this port, but it doesn't hurt to
         * allow forwarding to it anyhow.  Maybe such a port will appear later
         * and we're pre-populating the flow table.
         */
    }

    nl_msg_put_u32(ctx->odp_actions, ODP_ACTION_ATTR_OUTPUT, odp_port);
    ctx->nf_output_iface = ofp_port;
}

static void
xlate_table_action(struct action_xlate_ctx *ctx, uint16_t in_port)
{
    if (ctx->recurse < MAX_RESUBMIT_RECURSION) {
        struct rule_dpif *rule;
        uint16_t old_in_port;

        /* Look up a flow with 'in_port' as the input port.  Then restore the
         * original input port (otherwise OFPP_NORMAL and OFPP_IN_PORT will
         * have surprising behavior). */
        old_in_port = ctx->flow.in_port;
        ctx->flow.in_port = in_port;
        rule = rule_dpif_lookup(ctx->ofproto, &ctx->flow);
        ctx->flow.in_port = old_in_port;

        if (ctx->resubmit_hook) {
            ctx->resubmit_hook(ctx, rule);
        }

        if (rule) {
            ctx->recurse++;
            do_xlate_actions(rule->up.actions, rule->up.n_actions, ctx);
            ctx->recurse--;
        }
    } else {
        static struct vlog_rate_limit recurse_rl = VLOG_RATE_LIMIT_INIT(1, 1);

        VLOG_ERR_RL(&recurse_rl, "NXAST_RESUBMIT recursed over %d times",
                    MAX_RESUBMIT_RECURSION);
    }
}

static void
flood_packets(struct ofproto_dpif *ofproto,
              uint16_t ofp_in_port, ovs_be32 mask,
              uint16_t *nf_output_iface, struct ofpbuf *odp_actions)
{
    struct ofport_dpif *ofport;

    HMAP_FOR_EACH (ofport, up.hmap_node, &ofproto->up.ports) {
        uint16_t ofp_port = ofport->up.ofp_port;
        if (ofp_port != ofp_in_port && !(ofport->up.opp.config & mask)) {
            nl_msg_put_u32(odp_actions, ODP_ACTION_ATTR_OUTPUT,
                           ofport->odp_port);
        }
    }
    *nf_output_iface = NF_OUT_FLOOD;
}

static void
xlate_output_action__(struct action_xlate_ctx *ctx,
                      uint16_t port, uint16_t max_len)
{
    uint16_t prev_nf_output_iface = ctx->nf_output_iface;

    ctx->nf_output_iface = NF_OUT_DROP;

    switch (port) {
    case OFPP_IN_PORT:
        add_output_action(ctx, ctx->flow.in_port);
        break;
    case OFPP_TABLE:
        xlate_table_action(ctx, ctx->flow.in_port);
        break;
    case OFPP_NORMAL:
        xlate_normal(ctx);
        break;
    case OFPP_FLOOD:
        flood_packets(ctx->ofproto, ctx->flow.in_port, htonl(OFPPC_NO_FLOOD),
                      &ctx->nf_output_iface, ctx->odp_actions);
        break;
    case OFPP_ALL:
        flood_packets(ctx->ofproto, ctx->flow.in_port, htonl(0),
                      &ctx->nf_output_iface, ctx->odp_actions);
        break;
    case OFPP_CONTROLLER:
        nl_msg_put_u64(ctx->odp_actions, ODP_ACTION_ATTR_CONTROLLER, max_len);
        break;
    case OFPP_LOCAL:
        add_output_action(ctx, OFPP_LOCAL);
        break;
    default:
        if (port != ctx->flow.in_port) {
            add_output_action(ctx, port);
        }
        break;
    }

    if (prev_nf_output_iface == NF_OUT_FLOOD) {
        ctx->nf_output_iface = NF_OUT_FLOOD;
    } else if (ctx->nf_output_iface == NF_OUT_DROP) {
        ctx->nf_output_iface = prev_nf_output_iface;
    } else if (prev_nf_output_iface != NF_OUT_DROP &&
               ctx->nf_output_iface != NF_OUT_FLOOD) {
        ctx->nf_output_iface = NF_OUT_MULTI;
    }
}

static void
xlate_output_action(struct action_xlate_ctx *ctx,
                    const struct ofp_action_output *oao)
{
    xlate_output_action__(ctx, ntohs(oao->port), ntohs(oao->max_len));
}

/* If the final ODP action in 'ctx' is "pop priority", drop it, as an
 * optimization, because we're going to add another action that sets the
 * priority immediately after, or because there are no actions following the
 * pop.  */
static void
remove_pop_action(struct action_xlate_ctx *ctx)
{
    if (ctx->odp_actions->size == ctx->last_pop_priority) {
        ctx->odp_actions->size -= NLA_ALIGN(NLA_HDRLEN);
        ctx->last_pop_priority = -1;
    }
}

static void
add_pop_action(struct action_xlate_ctx *ctx)
{
    if (ctx->odp_actions->size != ctx->last_pop_priority) {
        nl_msg_put_flag(ctx->odp_actions, ODP_ACTION_ATTR_POP_PRIORITY);
        ctx->last_pop_priority = ctx->odp_actions->size;
    }
}

static void
xlate_enqueue_action(struct action_xlate_ctx *ctx,
                     const struct ofp_action_enqueue *oae)
{
    uint16_t ofp_port, odp_port;
    uint32_t priority;
    int error;

    error = dpif_queue_to_priority(ctx->ofproto->dpif, ntohl(oae->queue_id),
                                   &priority);
    if (error) {
        /* Fall back to ordinary output action. */
        xlate_output_action__(ctx, ntohs(oae->port), 0);
        return;
    }

    /* Figure out ODP output port. */
    ofp_port = ntohs(oae->port);
    if (ofp_port == OFPP_IN_PORT) {
        ofp_port = ctx->flow.in_port;
    }
    odp_port = ofp_port_to_odp_port(ofp_port);

    /* Add ODP actions. */
    remove_pop_action(ctx);
    nl_msg_put_u32(ctx->odp_actions, ODP_ACTION_ATTR_SET_PRIORITY, priority);
    add_output_action(ctx, odp_port);
    add_pop_action(ctx);

    /* Update NetFlow output port. */
    if (ctx->nf_output_iface == NF_OUT_DROP) {
        ctx->nf_output_iface = odp_port;
    } else if (ctx->nf_output_iface != NF_OUT_FLOOD) {
        ctx->nf_output_iface = NF_OUT_MULTI;
    }
}

static void
xlate_set_queue_action(struct action_xlate_ctx *ctx,
                       const struct nx_action_set_queue *nasq)
{
    uint32_t priority;
    int error;

    error = dpif_queue_to_priority(ctx->ofproto->dpif, ntohl(nasq->queue_id),
                                   &priority);
    if (error) {
        /* Couldn't translate queue to a priority, so ignore.  A warning
         * has already been logged. */
        return;
    }

    remove_pop_action(ctx);
    nl_msg_put_u32(ctx->odp_actions, ODP_ACTION_ATTR_SET_PRIORITY, priority);
}

static void
xlate_set_dl_tci(struct action_xlate_ctx *ctx)
{
    ovs_be16 tci = ctx->flow.vlan_tci;
    if (!(tci & htons(VLAN_CFI))) {
        nl_msg_put_flag(ctx->odp_actions, ODP_ACTION_ATTR_STRIP_VLAN);
    } else {
        nl_msg_put_be16(ctx->odp_actions, ODP_ACTION_ATTR_SET_DL_TCI,
                        tci & ~htons(VLAN_CFI));
    }
}

struct xlate_reg_state {
    ovs_be16 vlan_tci;
    ovs_be64 tun_id;
};

static void
save_reg_state(const struct action_xlate_ctx *ctx,
               struct xlate_reg_state *state)
{
    state->vlan_tci = ctx->flow.vlan_tci;
    state->tun_id = ctx->flow.tun_id;
}

static void
update_reg_state(struct action_xlate_ctx *ctx,
                 const struct xlate_reg_state *state)
{
    if (ctx->flow.vlan_tci != state->vlan_tci) {
        xlate_set_dl_tci(ctx);
    }
    if (ctx->flow.tun_id != state->tun_id) {
        nl_msg_put_be64(ctx->odp_actions,
                        ODP_ACTION_ATTR_SET_TUNNEL, ctx->flow.tun_id);
    }
}

static void
xlate_autopath(struct action_xlate_ctx *ctx,
               const struct nx_action_autopath *naa)
{
    uint16_t ofp_port = ntohl(naa->id);
    struct ofport_dpif *port = get_ofp_port(ctx->ofproto, ofp_port);

    if (!port || !port->bundle) {
        ofp_port = OFPP_NONE;
    } else if (port->bundle->bond) {
        /* Autopath does not support VLAN hashing. */
        struct ofport_dpif *slave = bond_choose_output_slave(
            port->bundle->bond, &ctx->flow, OFP_VLAN_NONE, &ctx->tags);
        if (slave) {
            ofp_port = slave->up.ofp_port;
        }
    }
    autopath_execute(naa, &ctx->flow, ofp_port);
}

static void
xlate_nicira_action(struct action_xlate_ctx *ctx,
                    const struct nx_action_header *nah)
{
    const struct nx_action_resubmit *nar;
    const struct nx_action_set_tunnel *nast;
    const struct nx_action_set_queue *nasq;
    const struct nx_action_multipath *nam;
    const struct nx_action_autopath *naa;
    enum nx_action_subtype subtype = ntohs(nah->subtype);
    struct xlate_reg_state state;
    ovs_be64 tun_id;

    assert(nah->vendor == htonl(NX_VENDOR_ID));
    switch (subtype) {
    case NXAST_RESUBMIT:
        nar = (const struct nx_action_resubmit *) nah;
        xlate_table_action(ctx, ntohs(nar->in_port));
        break;

    case NXAST_SET_TUNNEL:
        nast = (const struct nx_action_set_tunnel *) nah;
        tun_id = htonll(ntohl(nast->tun_id));
        nl_msg_put_be64(ctx->odp_actions, ODP_ACTION_ATTR_SET_TUNNEL, tun_id);
        ctx->flow.tun_id = tun_id;
        break;

    case NXAST_DROP_SPOOFED_ARP:
        if (ctx->flow.dl_type == htons(ETH_TYPE_ARP)) {
            nl_msg_put_flag(ctx->odp_actions,
                            ODP_ACTION_ATTR_DROP_SPOOFED_ARP);
        }
        break;

    case NXAST_SET_QUEUE:
        nasq = (const struct nx_action_set_queue *) nah;
        xlate_set_queue_action(ctx, nasq);
        break;

    case NXAST_POP_QUEUE:
        add_pop_action(ctx);
        break;

    case NXAST_REG_MOVE:
        save_reg_state(ctx, &state);
        nxm_execute_reg_move((const struct nx_action_reg_move *) nah,
                             &ctx->flow);
        update_reg_state(ctx, &state);
        break;

    case NXAST_REG_LOAD:
        save_reg_state(ctx, &state);
        nxm_execute_reg_load((const struct nx_action_reg_load *) nah,
                             &ctx->flow);
        update_reg_state(ctx, &state);
        break;

    case NXAST_NOTE:
        /* Nothing to do. */
        break;

    case NXAST_SET_TUNNEL64:
        tun_id = ((const struct nx_action_set_tunnel64 *) nah)->tun_id;
        nl_msg_put_be64(ctx->odp_actions, ODP_ACTION_ATTR_SET_TUNNEL, tun_id);
        ctx->flow.tun_id = tun_id;
        break;

    case NXAST_MULTIPATH:
        nam = (const struct nx_action_multipath *) nah;
        multipath_execute(nam, &ctx->flow);
        break;

    case NXAST_AUTOPATH:
        naa = (const struct nx_action_autopath *) nah;
        xlate_autopath(ctx, naa);
        break;

    /* If you add a new action here that modifies flow data, don't forget to
     * update the flow key in ctx->flow at the same time. */

    case NXAST_SNAT__OBSOLETE:
    default:
        VLOG_DBG_RL(&rl, "unknown Nicira action type %d", (int) subtype);
        break;
    }
}

static void
do_xlate_actions(const union ofp_action *in, size_t n_in,
                 struct action_xlate_ctx *ctx)
{
    const struct ofport_dpif *port;
    struct actions_iterator iter;
    const union ofp_action *ia;

    port = get_ofp_port(ctx->ofproto, ctx->flow.in_port);
    if (port
        && port->up.opp.config & htonl(OFPPC_NO_RECV | OFPPC_NO_RECV_STP) &&
        port->up.opp.config & (eth_addr_equals(ctx->flow.dl_dst, eth_addr_stp)
                               ? htonl(OFPPC_NO_RECV_STP)
                               : htonl(OFPPC_NO_RECV))) {
        /* Drop this flow. */
        return;
    }

    for (ia = actions_first(&iter, in, n_in); ia; ia = actions_next(&iter)) {
        enum ofp_action_type type = ntohs(ia->type);
        const struct ofp_action_dl_addr *oada;

        switch (type) {
        case OFPAT_OUTPUT:
            xlate_output_action(ctx, &ia->output);
            break;

        case OFPAT_SET_VLAN_VID:
            ctx->flow.vlan_tci &= ~htons(VLAN_VID_MASK);
            ctx->flow.vlan_tci |= ia->vlan_vid.vlan_vid | htons(VLAN_CFI);
            xlate_set_dl_tci(ctx);
            break;

        case OFPAT_SET_VLAN_PCP:
            ctx->flow.vlan_tci &= ~htons(VLAN_PCP_MASK);
            ctx->flow.vlan_tci |= htons(
                (ia->vlan_pcp.vlan_pcp << VLAN_PCP_SHIFT) | VLAN_CFI);
            xlate_set_dl_tci(ctx);
            break;

        case OFPAT_STRIP_VLAN:
            ctx->flow.vlan_tci = htons(0);
            xlate_set_dl_tci(ctx);
            break;

        case OFPAT_SET_DL_SRC:
            oada = ((struct ofp_action_dl_addr *) ia);
            nl_msg_put_unspec(ctx->odp_actions, ODP_ACTION_ATTR_SET_DL_SRC,
                              oada->dl_addr, ETH_ADDR_LEN);
            memcpy(ctx->flow.dl_src, oada->dl_addr, ETH_ADDR_LEN);
            break;

        case OFPAT_SET_DL_DST:
            oada = ((struct ofp_action_dl_addr *) ia);
            nl_msg_put_unspec(ctx->odp_actions, ODP_ACTION_ATTR_SET_DL_DST,
                              oada->dl_addr, ETH_ADDR_LEN);
            memcpy(ctx->flow.dl_dst, oada->dl_addr, ETH_ADDR_LEN);
            break;

        case OFPAT_SET_NW_SRC:
            nl_msg_put_be32(ctx->odp_actions, ODP_ACTION_ATTR_SET_NW_SRC,
                            ia->nw_addr.nw_addr);
            ctx->flow.nw_src = ia->nw_addr.nw_addr;
            break;

        case OFPAT_SET_NW_DST:
            nl_msg_put_be32(ctx->odp_actions, ODP_ACTION_ATTR_SET_NW_DST,
                            ia->nw_addr.nw_addr);
            ctx->flow.nw_dst = ia->nw_addr.nw_addr;
            break;

        case OFPAT_SET_NW_TOS:
            nl_msg_put_u8(ctx->odp_actions, ODP_ACTION_ATTR_SET_NW_TOS,
                          ia->nw_tos.nw_tos);
            ctx->flow.nw_tos = ia->nw_tos.nw_tos;
            break;

        case OFPAT_SET_TP_SRC:
            nl_msg_put_be16(ctx->odp_actions, ODP_ACTION_ATTR_SET_TP_SRC,
                            ia->tp_port.tp_port);
            ctx->flow.tp_src = ia->tp_port.tp_port;
            break;

        case OFPAT_SET_TP_DST:
            nl_msg_put_be16(ctx->odp_actions, ODP_ACTION_ATTR_SET_TP_DST,
                            ia->tp_port.tp_port);
            ctx->flow.tp_dst = ia->tp_port.tp_port;
            break;

        case OFPAT_VENDOR:
            xlate_nicira_action(ctx, (const struct nx_action_header *) ia);
            break;

        case OFPAT_ENQUEUE:
            xlate_enqueue_action(ctx, (const struct ofp_action_enqueue *) ia);
            break;

        default:
            VLOG_DBG_RL(&rl, "unknown action type %d", (int) type);
            break;
        }
    }
}

static void
action_xlate_ctx_init(struct action_xlate_ctx *ctx,
                      struct ofproto_dpif *ofproto, const struct flow *flow,
                      const struct ofpbuf *packet)
{
    ctx->ofproto = ofproto;
    ctx->flow = *flow;
    ctx->packet = packet;
    ctx->resubmit_hook = NULL;
}

static struct ofpbuf *
xlate_actions(struct action_xlate_ctx *ctx,
              const union ofp_action *in, size_t n_in)
{
    COVERAGE_INC(ofproto_dpif_xlate);

    ctx->odp_actions = ofpbuf_new(512);
    ctx->tags = 0;
    ctx->may_set_up_flow = true;
    ctx->nf_output_iface = NF_OUT_DROP;
    ctx->recurse = 0;
    ctx->last_pop_priority = -1;

    if (process_special(ctx->ofproto, &ctx->flow, ctx->packet)) {
        ctx->may_set_up_flow = false;
    } else {
        do_xlate_actions(in, n_in, ctx);
    }

    remove_pop_action(ctx);

    /* Check with in-band control to see if we're allowed to set up this
     * flow. */
    if (!connmgr_may_set_up_flow(ctx->ofproto->up.connmgr, &ctx->flow,
                                 ctx->odp_actions->data,
                                 ctx->odp_actions->size)) {
        ctx->may_set_up_flow = false;
    }

    return ctx->odp_actions;
}

/* OFPP_NORMAL implementation. */

struct dst {
    struct ofport_dpif *port;
    uint16_t vlan;
};

struct dst_set {
    struct dst builtin[32];
    struct dst *dsts;
    size_t n, allocated;
};

static void dst_set_init(struct dst_set *);
static void dst_set_add(struct dst_set *, const struct dst *);
static void dst_set_free(struct dst_set *);

static struct ofport_dpif *ofbundle_get_a_port(const struct ofbundle *);

static bool
set_dst(struct action_xlate_ctx *ctx, struct dst *dst,
        const struct ofbundle *in_bundle, const struct ofbundle *out_bundle)
{
    dst->vlan = (out_bundle->vlan >= 0 ? OFP_VLAN_NONE
                 : in_bundle->vlan >= 0 ? in_bundle->vlan
                 : ctx->flow.vlan_tci == 0 ? OFP_VLAN_NONE
                 : vlan_tci_to_vid(ctx->flow.vlan_tci));

    dst->port = (!out_bundle->bond
                 ? ofbundle_get_a_port(out_bundle)
                 : bond_choose_output_slave(out_bundle->bond, &ctx->flow,
                                            dst->vlan, &ctx->tags));

    return dst->port != NULL;
}

static int
mirror_mask_ffs(mirror_mask_t mask)
{
    BUILD_ASSERT_DECL(sizeof(unsigned int) >= sizeof(mask));
    return ffs(mask);
}

static void
dst_set_init(struct dst_set *set)
{
    set->dsts = set->builtin;
    set->n = 0;
    set->allocated = ARRAY_SIZE(set->builtin);
}

static void
dst_set_add(struct dst_set *set, const struct dst *dst)
{
    if (set->n >= set->allocated) {
        size_t new_allocated;
        struct dst *new_dsts;

        new_allocated = set->allocated * 2;
        new_dsts = xmalloc(new_allocated * sizeof *new_dsts);
        memcpy(new_dsts, set->dsts, set->n * sizeof *new_dsts);

        dst_set_free(set);

        set->dsts = new_dsts;
        set->allocated = new_allocated;
    }
    set->dsts[set->n++] = *dst;
}

static void
dst_set_free(struct dst_set *set)
{
    if (set->dsts != set->builtin) {
        free(set->dsts);
    }
}

static bool
dst_is_duplicate(const struct dst_set *set, const struct dst *test)
{
    size_t i;
    for (i = 0; i < set->n; i++) {
        if (set->dsts[i].vlan == test->vlan
            && set->dsts[i].port == test->port) {
            return true;
        }
    }
    return false;
}

static bool
ofbundle_trunks_vlan(const struct ofbundle *bundle, uint16_t vlan)
{
    return bundle->vlan < 0 && vlan_bitmap_contains(bundle->trunks, vlan);
}

static bool
ofbundle_includes_vlan(const struct ofbundle *bundle, uint16_t vlan)
{
    return vlan == bundle->vlan || ofbundle_trunks_vlan(bundle, vlan);
}

/* Returns an arbitrary interface within 'bundle'. */
static struct ofport_dpif *
ofbundle_get_a_port(const struct ofbundle *bundle)
{
    return CONTAINER_OF(list_front(&bundle->ports),
                        struct ofport_dpif, bundle_node);
}

static void
compose_dsts(struct action_xlate_ctx *ctx, uint16_t vlan,
             const struct ofbundle *in_bundle,
             const struct ofbundle *out_bundle, struct dst_set *set)
{
    struct dst dst;

    if (out_bundle == OFBUNDLE_FLOOD) {
        struct ofbundle *bundle;

        HMAP_FOR_EACH (bundle, hmap_node, &ctx->ofproto->bundles) {
            if (bundle != in_bundle
                && ofbundle_includes_vlan(bundle, vlan)
                && bundle->floodable
                && !bundle->mirror_out
                && set_dst(ctx, &dst, in_bundle, bundle)) {
                dst_set_add(set, &dst);
            }
        }
        ctx->nf_output_iface = NF_OUT_FLOOD;
    } else if (out_bundle && set_dst(ctx, &dst, in_bundle, out_bundle)) {
        dst_set_add(set, &dst);
        ctx->nf_output_iface = dst.port->odp_port;
    }
}

static bool
vlan_is_mirrored(const struct ofmirror *m, int vlan)
{
    return vlan_bitmap_contains(m->vlans, vlan);
}

static void
compose_mirror_dsts(struct action_xlate_ctx *ctx,
                    uint16_t vlan, const struct ofbundle *in_bundle,
                    struct dst_set *set)
{
    struct ofproto_dpif *ofproto = ctx->ofproto;
    mirror_mask_t mirrors;
    int flow_vlan;
    size_t i;

    mirrors = in_bundle->src_mirrors;
    for (i = 0; i < set->n; i++) {
        mirrors |= set->dsts[i].port->bundle->dst_mirrors;
    }

    if (!mirrors) {
        return;
    }

    flow_vlan = vlan_tci_to_vid(ctx->flow.vlan_tci);
    if (flow_vlan == 0) {
        flow_vlan = OFP_VLAN_NONE;
    }

    while (mirrors) {
        struct ofmirror *m = ofproto->mirrors[mirror_mask_ffs(mirrors) - 1];
        if (vlan_is_mirrored(m, vlan)) {
            struct dst dst;

            if (m->out) {
                if (set_dst(ctx, &dst, in_bundle, m->out)
                    && !dst_is_duplicate(set, &dst)) {
                    dst_set_add(set, &dst);
                }
            } else {
                struct ofbundle *bundle;

                HMAP_FOR_EACH (bundle, hmap_node, &ofproto->bundles) {
                    if (ofbundle_includes_vlan(bundle, m->out_vlan)
                        && set_dst(ctx, &dst, in_bundle, bundle))
                    {
                        if (bundle->vlan < 0) {
                            dst.vlan = m->out_vlan;
                        }
                        if (dst_is_duplicate(set, &dst)) {
                            continue;
                        }

                        /* Use the vlan tag on the original flow instead of
                         * the one passed in the vlan parameter.  This ensures
                         * that we compare the vlan from before any implicit
                         * tagging tags place. This is necessary because
                         * dst->vlan is the final vlan, after removing implicit
                         * tags. */
                        if (bundle == in_bundle && dst.vlan == flow_vlan) {
                            /* Don't send out input port on same VLAN. */
                            continue;
                        }
                        dst_set_add(set, &dst);
                    }
                }
            }
        }
        mirrors &= mirrors - 1;
    }
}

static void
compose_actions(struct action_xlate_ctx *ctx, uint16_t vlan,
                const struct ofbundle *in_bundle,
                const struct ofbundle *out_bundle)
{
    uint16_t initial_vlan, cur_vlan;
    const struct dst *dst;
    struct dst_set set;

    dst_set_init(&set);
    compose_dsts(ctx, vlan, in_bundle, out_bundle, &set);
    compose_mirror_dsts(ctx, vlan, in_bundle, &set);

    /* Output all the packets we can without having to change the VLAN. */
    initial_vlan = vlan_tci_to_vid(ctx->flow.vlan_tci);
    if (initial_vlan == 0) {
        initial_vlan = OFP_VLAN_NONE;
    }
    for (dst = set.dsts; dst < &set.dsts[set.n]; dst++) {
        if (dst->vlan != initial_vlan) {
            continue;
        }
        nl_msg_put_u32(ctx->odp_actions,
                       ODP_ACTION_ATTR_OUTPUT, dst->port->odp_port);
    }

    /* Then output the rest. */
    cur_vlan = initial_vlan;
    for (dst = set.dsts; dst < &set.dsts[set.n]; dst++) {
        if (dst->vlan == initial_vlan) {
            continue;
        }
        if (dst->vlan != cur_vlan) {
            if (dst->vlan == OFP_VLAN_NONE) {
                nl_msg_put_flag(ctx->odp_actions, ODP_ACTION_ATTR_STRIP_VLAN);
            } else {
                ovs_be16 tci;
                tci = htons(dst->vlan & VLAN_VID_MASK);
                tci |= ctx->flow.vlan_tci & htons(VLAN_PCP_MASK);
                nl_msg_put_be16(ctx->odp_actions,
                                ODP_ACTION_ATTR_SET_DL_TCI, tci);
            }
            cur_vlan = dst->vlan;
        }
        nl_msg_put_u32(ctx->odp_actions,
                       ODP_ACTION_ATTR_OUTPUT, dst->port->odp_port);
    }

    dst_set_free(&set);
}

/* Returns the effective vlan of a packet, taking into account both the
 * 802.1Q header and implicitly tagged ports.  A value of 0 indicates that
 * the packet is untagged and -1 indicates it has an invalid header and
 * should be dropped. */
static int
flow_get_vlan(struct ofproto_dpif *ofproto, const struct flow *flow,
              struct ofbundle *in_bundle, bool have_packet)
{
    int vlan = vlan_tci_to_vid(flow->vlan_tci);
    if (in_bundle->vlan >= 0) {
        if (vlan) {
            if (have_packet) {
                static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
                VLOG_WARN_RL(&rl, "bridge %s: dropping VLAN %d tagged "
                             "packet received on port %s configured with "
                             "implicit VLAN %"PRIu16,
                             ofproto->up.name, vlan,
                             in_bundle->name, in_bundle->vlan);
            }
            return -1;
        }
        vlan = in_bundle->vlan;
    } else {
        if (!ofbundle_includes_vlan(in_bundle, vlan)) {
            if (have_packet) {
                static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
                VLOG_WARN_RL(&rl, "bridge %s: dropping VLAN %d tagged "
                             "packet received on port %s not configured for "
                             "trunking VLAN %d",
                             ofproto->up.name, vlan, in_bundle->name, vlan);
            }
            return -1;
        }
    }

    return vlan;
}

/* A VM broadcasts a gratuitous ARP to indicate that it has resumed after
 * migration.  Older Citrix-patched Linux DomU used gratuitous ARP replies to
 * indicate this; newer upstream kernels use gratuitous ARP requests. */
static bool
is_gratuitous_arp(const struct flow *flow)
{
    return (flow->dl_type == htons(ETH_TYPE_ARP)
            && eth_addr_is_broadcast(flow->dl_dst)
            && (flow->nw_proto == ARP_OP_REPLY
                || (flow->nw_proto == ARP_OP_REQUEST
                    && flow->nw_src == flow->nw_dst)));
}

static void
update_learning_table(struct ofproto_dpif *ofproto,
                      const struct flow *flow, int vlan,
                      struct ofbundle *in_bundle)
{
    struct mac_entry *mac;

    if (!mac_learning_may_learn(ofproto->ml, flow->dl_src, vlan)) {
        return;
    }

    mac = mac_learning_insert(ofproto->ml, flow->dl_src, vlan);
    if (is_gratuitous_arp(flow)) {
        /* We don't want to learn from gratuitous ARP packets that are
         * reflected back over bond slaves so we lock the learning table. */
        if (!in_bundle->bond) {
            mac_entry_set_grat_arp_lock(mac);
        } else if (mac_entry_is_grat_arp_locked(mac)) {
            return;
        }
    }

    if (mac_entry_is_new(mac) || mac->port.p != in_bundle) {
        /* The log messages here could actually be useful in debugging,
         * so keep the rate limit relatively high. */
        static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(30, 300);
        VLOG_DBG_RL(&rl, "bridge %s: learned that "ETH_ADDR_FMT" is "
                    "on port %s in VLAN %d",
                    ofproto->up.name, ETH_ADDR_ARGS(flow->dl_src),
                    in_bundle->name, vlan);

        mac->port.p = in_bundle;
        tag_set_add(&ofproto->revalidate_set,
                    mac_learning_changed(ofproto->ml, mac));
    }
}

/* Determines whether packets in 'flow' within 'br' should be forwarded or
 * dropped.  Returns true if they may be forwarded, false if they should be
 * dropped.
 *
 * If 'have_packet' is true, it indicates that the caller is processing a
 * received packet.  If 'have_packet' is false, then the caller is just
 * revalidating an existing flow because configuration has changed.  Either
 * way, 'have_packet' only affects logging (there is no point in logging errors
 * during revalidation).
 *
 * Sets '*in_portp' to the input port.  This will be a null pointer if
 * flow->in_port does not designate a known input port (in which case
 * is_admissible() returns false).
 *
 * When returning true, sets '*vlanp' to the effective VLAN of the input
 * packet, as returned by flow_get_vlan().
 *
 * May also add tags to '*tags', although the current implementation only does
 * so in one special case.
 */
static bool
is_admissible(struct ofproto_dpif *ofproto, const struct flow *flow,
              bool have_packet,
              tag_type *tags, int *vlanp, struct ofbundle **in_bundlep)
{
    struct ofport_dpif *in_port;
    struct ofbundle *in_bundle;
    int vlan;

    /* Find the port and bundle for the received packet. */
    in_port = get_ofp_port(ofproto, flow->in_port);
    *in_bundlep = in_bundle = in_port ? in_port->bundle : NULL;
    if (!in_port || !in_bundle) {
        /* No interface?  Something fishy... */
        if (have_packet) {
            /* Odd.  A few possible reasons here:
             *
             * - We deleted a port but there are still a few packets queued up
             *   from it.
             *
             * - Someone externally added a port (e.g. "ovs-dpctl add-if") that
             *   we don't know about.
             *
             * - Packet arrived on the local port but the local port is not
             *   part of a bundle.
             */
            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);

            VLOG_WARN_RL(&rl, "bridge %s: received packet on unknown "
                         "port %"PRIu16,
                         ofproto->up.name, flow->in_port);
        }
        return false;
    }
    *vlanp = vlan = flow_get_vlan(ofproto, flow, in_bundle, have_packet);
    if (vlan < 0) {
        return false;
    }

    /* Drop frames for reserved multicast addresses. */
    if (eth_addr_is_reserved(flow->dl_dst)) {
        return false;
    }

    /* Drop frames on bundles reserved for mirroring. */
    if (in_bundle->mirror_out) {
        if (have_packet) {
            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
            VLOG_WARN_RL(&rl, "bridge %s: dropping packet received on port "
                         "%s, which is reserved exclusively for mirroring",
                         ofproto->up.name, in_bundle->name);
        }
        return false;
    }

    if (in_bundle->bond) {
        struct mac_entry *mac;

        switch (bond_check_admissibility(in_bundle->bond, in_port,
                                         flow->dl_dst, tags)) {
        case BV_ACCEPT:
            break;

        case BV_DROP:
            return false;

        case BV_DROP_IF_MOVED:
            mac = mac_learning_lookup(ofproto->ml, flow->dl_src, vlan, NULL);
            if (mac && mac->port.p != in_bundle &&
                (!is_gratuitous_arp(flow)
                 || mac_entry_is_grat_arp_locked(mac))) {
                return false;
            }
            break;
        }
    }

    return true;
}

/* If the composed actions may be applied to any packet in the given 'flow',
 * returns true.  Otherwise, the actions should only be applied to 'packet', or
 * not at all, if 'packet' was NULL. */
static bool
xlate_normal(struct action_xlate_ctx *ctx)
{
    struct ofbundle *in_bundle;
    struct ofbundle *out_bundle;
    struct mac_entry *mac;
    int vlan;

    /* Check whether we should drop packets in this flow. */
    if (!is_admissible(ctx->ofproto, &ctx->flow, ctx->packet != NULL,
                       &ctx->tags, &vlan, &in_bundle)) {
        out_bundle = NULL;
        goto done;
    }

    /* Learn source MAC (but don't try to learn from revalidation). */
    if (ctx->packet) {
        update_learning_table(ctx->ofproto, &ctx->flow, vlan, in_bundle);
    }

    /* Determine output bundle. */
    mac = mac_learning_lookup(ctx->ofproto->ml, ctx->flow.dl_dst, vlan,
                              &ctx->tags);
    if (mac) {
        out_bundle = mac->port.p;
    } else if (!ctx->packet && !eth_addr_is_multicast(ctx->flow.dl_dst)) {
        /* If we are revalidating but don't have a learning entry then eject
         * the flow.  Installing a flow that floods packets opens up a window
         * of time where we could learn from a packet reflected on a bond and
         * blackhole packets before the learning table is updated to reflect
         * the correct port. */
        return false;
    } else {
        out_bundle = OFBUNDLE_FLOOD;
    }

    /* Don't send packets out their input bundles. */
    if (in_bundle == out_bundle) {
        out_bundle = NULL;
    }

done:
    if (in_bundle) {
        compose_actions(ctx, vlan, in_bundle, out_bundle);
    }

    return true;
}

static bool
get_drop_frags(struct ofproto *ofproto_)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    bool drop_frags;

    dpif_get_drop_frags(ofproto->dpif, &drop_frags);
    return drop_frags;
}

static void
set_drop_frags(struct ofproto *ofproto_, bool drop_frags)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);

    dpif_set_drop_frags(ofproto->dpif, drop_frags);
}

static int
packet_out(struct ofproto *ofproto_, struct ofpbuf *packet,
           const struct flow *flow,
           const union ofp_action *ofp_actions, size_t n_ofp_actions)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);
    int error;

    error = validate_actions(ofp_actions, n_ofp_actions, flow,
                             ofproto->max_ports);
    if (!error) {
        struct action_xlate_ctx ctx;
        struct ofpbuf *odp_actions;

        action_xlate_ctx_init(&ctx, ofproto, flow, packet);
        odp_actions = xlate_actions(&ctx, ofp_actions, n_ofp_actions);
        dpif_execute(ofproto->dpif, odp_actions->data, odp_actions->size,
                     packet);
        ofpbuf_delete(odp_actions);
    }
    return error;
}

static void
get_netflow_ids(const struct ofproto *ofproto_,
                uint8_t *engine_type, uint8_t *engine_id)
{
    struct ofproto_dpif *ofproto = ofproto_dpif_cast(ofproto_);

    dpif_get_netflow_ids(ofproto->dpif, engine_type, engine_id);
}

static struct ofproto_dpif *
ofproto_dpif_lookup(const char *name)
{
    struct ofproto *ofproto = ofproto_lookup(name);
    return (ofproto && ofproto->ofproto_class == &ofproto_dpif_class
            ? ofproto_dpif_cast(ofproto)
            : NULL);
}

static void
ofproto_unixctl_fdb_show(struct unixctl_conn *conn,
                         const char *args, void *aux OVS_UNUSED)
{
    struct ds ds = DS_EMPTY_INITIALIZER;
    const struct ofproto_dpif *ofproto;
    const struct mac_entry *e;

    ofproto = ofproto_dpif_lookup(args);
    if (!ofproto) {
        unixctl_command_reply(conn, 501, "no such bridge");
        return;
    }

    ds_put_cstr(&ds, " port  VLAN  MAC                Age\n");
    LIST_FOR_EACH (e, lru_node, &ofproto->ml->lrus) {
        struct ofbundle *bundle = e->port.p;
        ds_put_format(&ds, "%5d  %4d  "ETH_ADDR_FMT"  %3d\n",
                      ofbundle_get_a_port(bundle)->odp_port,
                      e->vlan, ETH_ADDR_ARGS(e->mac), mac_entry_age(e));
    }
    unixctl_command_reply(conn, 200, ds_cstr(&ds));
    ds_destroy(&ds);
}

struct ofproto_trace {
    struct action_xlate_ctx ctx;
    struct flow flow;
    struct ds *result;
};

static void
trace_format_rule(struct ds *result, int level, const struct rule *rule)
{
    ds_put_char_multiple(result, '\t', level);
    if (!rule) {
        ds_put_cstr(result, "No match\n");
        return;
    }

    ds_put_format(result, "Rule: cookie=%#"PRIx64" ",
                  ntohll(rule->flow_cookie));
    cls_rule_format(&rule->cr, result);
    ds_put_char(result, '\n');

    ds_put_char_multiple(result, '\t', level);
    ds_put_cstr(result, "OpenFlow ");
    ofp_print_actions(result, (const struct ofp_action_header *) rule->actions,
                      rule->n_actions * sizeof *rule->actions);
    ds_put_char(result, '\n');
}

static void
trace_format_flow(struct ds *result, int level, const char *title,
                 struct ofproto_trace *trace)
{
    ds_put_char_multiple(result, '\t', level);
    ds_put_format(result, "%s: ", title);
    if (flow_equal(&trace->ctx.flow, &trace->flow)) {
        ds_put_cstr(result, "unchanged");
    } else {
        flow_format(result, &trace->ctx.flow);
        trace->flow = trace->ctx.flow;
    }
    ds_put_char(result, '\n');
}

static void
trace_resubmit(struct action_xlate_ctx *ctx, struct rule_dpif *rule)
{
    struct ofproto_trace *trace = CONTAINER_OF(ctx, struct ofproto_trace, ctx);
    struct ds *result = trace->result;

    ds_put_char(result, '\n');
    trace_format_flow(result, ctx->recurse + 1, "Resubmitted flow", trace);
    trace_format_rule(result, ctx->recurse + 1, &rule->up);
}

static void
ofproto_unixctl_trace(struct unixctl_conn *conn, const char *args_,
                      void *aux OVS_UNUSED)
{
    char *dpname, *in_port_s, *tun_id_s, *packet_s;
    char *args = xstrdup(args_);
    char *save_ptr = NULL;
    struct ofproto_dpif *ofproto;
    struct ofpbuf packet;
    struct rule_dpif *rule;
    struct ds result;
    struct flow flow;
    uint16_t in_port;
    ovs_be64 tun_id;
    char *s;

    ofpbuf_init(&packet, strlen(args) / 2);
    ds_init(&result);

    dpname = strtok_r(args, " ", &save_ptr);
    tun_id_s = strtok_r(NULL, " ", &save_ptr);
    in_port_s = strtok_r(NULL, " ", &save_ptr);
    packet_s = strtok_r(NULL, "", &save_ptr); /* Get entire rest of line. */
    if (!dpname || !in_port_s || !packet_s) {
        unixctl_command_reply(conn, 501, "Bad command syntax");
        goto exit;
    }

    ofproto = ofproto_dpif_lookup(dpname);
    if (!ofproto) {
        unixctl_command_reply(conn, 501, "Unknown ofproto (use ofproto/list "
                              "for help)");
        goto exit;
    }

    tun_id = htonll(strtoull(tun_id_s, NULL, 0));
    in_port = ofp_port_to_odp_port(atoi(in_port_s));

    packet_s = ofpbuf_put_hex(&packet, packet_s, NULL);
    packet_s += strspn(packet_s, " ");
    if (*packet_s != '\0') {
        unixctl_command_reply(conn, 501, "Trailing garbage in command");
        goto exit;
    }
    if (packet.size < ETH_HEADER_LEN) {
        unixctl_command_reply(conn, 501, "Packet data too short for Ethernet");
        goto exit;
    }

    ds_put_cstr(&result, "Packet: ");
    s = ofp_packet_to_string(packet.data, packet.size, packet.size);
    ds_put_cstr(&result, s);
    free(s);

    flow_extract(&packet, tun_id, in_port, &flow);
    ds_put_cstr(&result, "Flow: ");
    flow_format(&result, &flow);
    ds_put_char(&result, '\n');

    rule = rule_dpif_lookup(ofproto, &flow);
    trace_format_rule(&result, 0, &rule->up);
    if (rule) {
        struct ofproto_trace trace;
        struct ofpbuf *odp_actions;

        trace.result = &result;
        trace.flow = flow;
        action_xlate_ctx_init(&trace.ctx, ofproto, &flow, &packet);
        trace.ctx.resubmit_hook = trace_resubmit;
        odp_actions = xlate_actions(&trace.ctx,
                                    rule->up.actions, rule->up.n_actions);

        ds_put_char(&result, '\n');
        trace_format_flow(&result, 0, "Final flow", &trace);
        ds_put_cstr(&result, "Datapath actions: ");
        format_odp_actions(&result, odp_actions->data, odp_actions->size);
        ofpbuf_delete(odp_actions);
    }

    unixctl_command_reply(conn, 200, ds_cstr(&result));

exit:
    ds_destroy(&result);
    ofpbuf_uninit(&packet);
    free(args);
}

static void
ofproto_dpif_unixctl_init(void)
{
    static bool registered;
    if (registered) {
        return;
    }
    registered = true;

    unixctl_command_register("ofproto/trace", ofproto_unixctl_trace, NULL);
    unixctl_command_register("fdb/show", ofproto_unixctl_fdb_show, NULL);
}

const struct ofproto_class ofproto_dpif_class = {
    enumerate_types,
    enumerate_names,
    del,
    alloc,
    construct,
    destruct,
    dealloc,
    run,
    wait,
    flush,
    get_features,
    get_tables,
    port_alloc,
    port_construct,
    port_destruct,
    port_dealloc,
    port_modified,
    port_reconfigured,
    port_query_by_name,
    port_add,
    port_del,
    port_dump_start,
    port_dump_next,
    port_dump_done,
    port_poll,
    port_poll_wait,
    port_is_lacp_current,
    rule_alloc,
    rule_construct,
    rule_destruct,
    rule_dealloc,
    rule_get_stats,
    rule_execute,
    rule_modify_actions,
    get_drop_frags,
    set_drop_frags,
    packet_out,
    set_netflow,
    get_netflow_ids,
    set_sflow,
    set_cfm,
    get_cfm,
    bundle_set,
    bundle_remove,
    mirror_set,
    set_flood_vlans,
    is_mirror_output_bundle,
};