[ovs-dev] [RFC V2] bfd: Replace bfd.{c, h} with generic implementation.

Alex Wang alexw at nicira.com
Wed Mar 5 18:58:10 UTC 2014


Look for high-level reviews.  Especially if it is clean to use the
"bfd-aux.h"
for platform dependent functions.

Thanks,
Alex Wang,


On Wed, Mar 5, 2014 at 10:56 AM, Alex Wang <alexw at nicira.com> wrote:

> This commit replaces the current bfd.{c,h} with a generic library-like
> implementation.  Wrappers (in bfd_ts.{c,h}) are then added to guarantee
> the thread-safety and compatibility with current invocation pattern.
>
> This commit also marks one-step forward in making Open Vswitch library
> codes generic and useful outside the project.
>
> Signed-off-by: Alex Wang <alexw at nicira.com>
>
> ---
> things I have in mind when coding:
> - the generic library should use no ovs specific data structures. (e.g.
> ofpbuf)
> - no malloc and thread-safety module should be used, since the generic
> library
>   is also expected to be used in non-linux system which may have different
> way
>   of doing those.
> - follow closely to the current ovs-bfd implementation.  also port the ovs
>   specific features.  e.g. decay and forward_if_rx.
>
> RFC -> RFC V2
> - add lib/bfd-aux.h and ask user to define the required platform dependent
>   functions/macros (e.g. for logging, random number generation).
> - add logging to lib/bfd.c.
> ---
>  lib/automake.mk                |    3 +
>  lib/bfd-aux.h                  |  114 ++++
>  lib/bfd.c                      | 1385
> ++++++++++++----------------------------
>  lib/bfd.h                      |  238 +++++--
>  lib/bfd_ts.c                   |  621 ++++++++++++++++++
>  lib/bfd_ts.h                   |   48 ++
>  ofproto/ofproto-dpif-monitor.c |   16 +-
>  ofproto/ofproto-dpif-xlate.c   |   22 +-
>  ofproto/ofproto-dpif.c         |   19 +-
>  9 files changed, 1423 insertions(+), 1043 deletions(-)
>  create mode 100644 lib/bfd-aux.h
>  create mode 100644 lib/bfd_ts.c
>  create mode 100644 lib/bfd_ts.h
>
> diff --git a/lib/automake.mk b/lib/automake.mk
> index 9c345e7..3e891e4 100644
> --- a/lib/automake.mk
> +++ b/lib/automake.mk
> @@ -16,8 +16,11 @@ lib_libopenvswitch_la_SOURCES = \
>         lib/async-append.h \
>         lib/backtrace.c \
>         lib/backtrace.h \
> +       lib/bfd-aux.h \
>         lib/bfd.c \
>         lib/bfd.h \
> +       lib/bfd_ts.c \
> +       lib/bfd_ts.h \
>         lib/bitmap.c \
>         lib/bitmap.h \
>         lib/bundle.c \
> diff --git a/lib/bfd-aux.h b/lib/bfd-aux.h
> new file mode 100644
> index 0000000..8c81b2d
> --- /dev/null
> +++ b/lib/bfd-aux.h
> @@ -0,0 +1,114 @@
> +/* Copyright (c) 2013 Nicira, Inc.
> + *
> + * 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. */
> +
> +#ifndef BFD_AUX_H
> +#define BFD_AUX_H 1
> +
> +/* The following functions and macros are used in bfd.c, but due to
> platform
> + * differences, not implemented.  Users are responsible for bridging the
> gap
> + * with the correct implementation.
> + *
> + *
> + * Per-Thread Variable Macro
> + * -------------------------
> + *
> + *     bfd_thread_local
> + *
> + *         To guarantee the thread-safety of the bfd_flag_to_str(), the
> + *         per-thread char buffer is created using this macro for holding
> the
> + *         parsed output.  Users are responsible for defining this macro.
> + *         e.g. if you are using C11:
> + *
> + *             #include <thread.h>
> + *             #define bfd_thread_local thread_local
> + *
> + *         Please note, the reentrancy is not guaranteed with this
> per-thread
> + *         macro.
> + *
> + * Random Number Generation
> + * ------------------------
> + *
> + *     bfd_get_random()
> + *
> + *         This should be a thread-safe function and returns a random
> unsigned
> + *         integer, which will be used as the jitter in bfd_set_next_ts().
> + *
> + * Logging
> + * -------
> + *
> + *     log-level macros:
> + *
> + *         Users are responsible for supporting the following log levels:
> + *
> + *         WARN   A low-level operation failed, but higher-level
> subsystems may
> + *                be able to recover.  e.g. BFD control packet format
> error.
> + *
> + *         INFO   Information that may be useful in retrospect when
> + *                investigating a problem.  e.g. POLL sequence start.
> + *
> + *         DBG    Information useful only to someone with intricate
> knowledge
> + *                of the system, or that would commonly cause
> too-voluminous
> + *                log output.  Log messages at this level are not logged
> by
> + *                default.  e.g. send and recv of BFD control packets.
> + *
> + *     bfd_log(level, format, ...)
> + *
> + *         This function logs the content given in the Variadic Macros
> "..."
> + *         with the specified 'level'.
> + *
> + *         To reduce logging overhead, users may also implement
> rate-limiting
> + *         logic, like shown in the following pseudocode:
> + *
> + *             bfd_log(level, format, ...)
> + *             {
> + *                 if (bfd_should_log(level)) {
> + *                     * logging code here. *
> + *                 }
> + *             }
> + * */
> +
> +#include "ovs-thread.h"
> +#include "random.h"
> +#include "vlog.h"
> +
> +VLOG_DEFINE_THIS_MODULE(bfd);
> +
> +#define bfd_thread_local thread_local
> +
> +#define bfd_get_random() random_uint32()
> +
> +static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(20, 20);
> +
> +/* Compatible with VLOG_LEVELS. */
> +enum bfd_log_levels {
> +    BFD_LOG_WARN = VLL_WARN,
> +    BFD_LOG_INFO = VLL_INFO,
> +    BFD_LOG_DBG = VLL_DBG
> +};
> +
> +#define bfd_should_log(LEVEL) !vlog_should_drop(THIS_MODULE, LEVEL, &rl)
> +
> +static void
> +bfd_log(enum bfd_log_levels level, const char *format, ...)
> +{
> +    if (bfd_should_log((enum vlog_level) level)) {
> +        va_list args;
> +
> +        va_start(args, format);
> +        vlog_valist(THIS_MODULE, (enum vlog_level) level, format, args);
> +        va_end(args);
> +    }
> +}
> +
> +#endif /* bfd-aux.h */
> diff --git a/lib/bfd.c b/lib/bfd.c
> index 5413105..c52799c 100644
> --- a/lib/bfd.c
> +++ b/lib/bfd.c
> @@ -13,363 +13,233 @@
>   * limitations under the License. */
>
>  #include <config.h>
> +
> +#include "bfd-aux.h"
>  #include "bfd.h"
>
> -#include <sys/types.h>
>  #include <arpa/inet.h>
> -#include <netinet/in_systm.h>
> -#include <netinet/ip.h>
> -
> -#include "byte-order.h"
> -#include "connectivity.h"
> -#include "csum.h"
> -#include "dpif.h"
> -#include "dynamic-string.h"
> -#include "flow.h"
> -#include "hash.h"
> -#include "hmap.h"
> -#include "list.h"
> -#include "netdev.h"
> -#include "netlink.h"
> -#include "odp-util.h"
> -#include "ofpbuf.h"
> -#include "ovs-thread.h"
> -#include "openvswitch/types.h"
> -#include "packets.h"
> -#include "poll-loop.h"
> -#include "random.h"
> -#include "seq.h"
> -#include "smap.h"
> -#include "timeval.h"
> -#include "unaligned.h"
> -#include "unixctl.h"
> -#include "util.h"
> -#include "vlog.h"
> -
> -VLOG_DEFINE_THIS_MODULE(bfd);
> -
> -/* XXX Finish BFD.
> - *
> - * The goal of this module is to replace CFM with something both more
> flexible
> - * and standards compliant.  In service of this goal, the following needs
> to be
> - * done.
> - *
> - * - Compliance
> - *   * Implement Demand mode.
> - *   * Go through the RFC line by line and verify we comply.
> - *   * Test against a hardware implementation.  Preferably a popular one.
> - *   * Delete BFD packets with nw_ttl != 255 in the datapath to prevent
> DOS
> - *     attacks.
> - *
> - * - Unit tests.
> - *
> - * - Set TOS/PCP on the outer tunnel header when encapped.
> - *
> - * - Sending BFD messages should be in its own thread/process.
> - *
> - * - Scale testing.  How does it operate when there are large number of
> bfd
> - *   sessions?  Do we ever have random flaps?  What's the CPU utilization?
> - *
> - * - Rely on data traffic for liveness by using BFD demand mode.
> - *   If we're receiving traffic on a port, we can safely assume it's up
> (modulo
> - *   unidrectional failures).  BFD has a demand mode in which it can stay
> quiet
> - *   unless it feels the need to check the status of the port.  Using
> this, we
> - *   can implement a strategy in which BFD only sends control messages on
> dark
> - *   interfaces.
> - *
> - * - Depending on how one interprets the spec, it appears that a BFD
> session
> - *   can never change bfd.LocalDiag to "No Diagnostic".  We should verify
> that
> - *   this is what hardware implementations actually do.  Seems like "No
> - *   Diagnostic" should be set once a BFD session state goes UP. */
> -
> -#define BFD_VERSION 1
> -
> -enum flags {
> -    FLAG_MULTIPOINT = 1 << 0,
> -    FLAG_DEMAND = 1 << 1,
> -    FLAG_AUTH = 1 << 2,
> -    FLAG_CTL = 1 << 3,
> -    FLAG_FINAL = 1 << 4,
> -    FLAG_POLL = 1 << 5
> -};
> -
> -enum state {
> -    STATE_ADMIN_DOWN = 0 << 6,
> -    STATE_DOWN = 1 << 6,
> -    STATE_INIT = 2 << 6,
> -    STATE_UP = 3 << 6
> -};
> -
> -enum diag {
> -    DIAG_NONE = 0,                /* No Diagnostic. */
> -    DIAG_EXPIRED = 1,             /* Control Detection Time Expired. */
> -    DIAG_ECHO_FAILED = 2,         /* Echo Function Failed. */
> -    DIAG_RMT_DOWN = 3,            /* Neighbor Signaled Session Down. */
> -    DIAG_FWD_RESET = 4,           /* Forwarding Plane Reset. */
> -    DIAG_PATH_DOWN = 5,           /* Path Down. */
> -    DIAG_CPATH_DOWN = 6,          /* Concatenated Path Down. */
> -    DIAG_ADMIN_DOWN = 7,          /* Administratively Down. */
> -    DIAG_RCPATH_DOWN = 8          /* Reverse Concatenated Path Down. */
> -};
> -
> -/* RFC 5880 Section 4.1
> - *  0                   1                   2                   3
> - *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> - * |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> - * |                       My Discriminator                        |
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> - * |                      Your Discriminator                       |
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> - * |                    Desired Min TX Interval                    |
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> - * |                   Required Min RX Interval                    |
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> - * |                 Required Min Echo RX Interval                 |
> - * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
> -struct msg {
> -    uint8_t vers_diag;    /* Version and diagnostic. */
> -    uint8_t flags;        /* 2bit State field followed by flags. */
> -    uint8_t mult;         /* Fault detection multiplier. */
> -    uint8_t length;       /* Length of this BFD message. */
> -    ovs_be32 my_disc;     /* My discriminator. */
> -    ovs_be32 your_disc;   /* Your discriminator. */
> -    ovs_be32 min_tx;      /* Desired minimum tx interval. */
> -    ovs_be32 min_rx;      /* Required minimum rx interval. */
> -    ovs_be32 min_rx_echo; /* Required minimum echo rx interval. */
> -};
> -BUILD_ASSERT_DECL(BFD_PACKET_LEN == sizeof(struct msg));
> -
> -#define DIAG_MASK 0x1f
> -#define VERS_SHIFT 5
> -#define STATE_MASK 0xC0
> -#define FLAGS_MASK 0x3f
> -
> -struct bfd {
> -    struct hmap_node node;        /* In 'all_bfds'. */
> -    uint32_t disc;                /* bfd.LocalDiscr. Key in 'all_bfds'
> hmap. */
> -
> -    char *name;                   /* Name used for logging. */
> -
> -    bool cpath_down;              /* Concatenated Path Down. */
> -    uint8_t mult;                 /* bfd.DetectMult. */
> -
> -    struct netdev *netdev;
> -    uint64_t rx_packets;          /* Packets received by 'netdev'. */
> -
> -    enum state state;             /* bfd.SessionState. */
> -    enum state rmt_state;         /* bfd.RemoteSessionState. */
> -
> -    enum diag diag;               /* bfd.LocalDiag. */
> -    enum diag rmt_diag;           /* Remote diagnostic. */
> -
> -    enum flags flags;             /* Flags sent on messages. */
> -    enum flags rmt_flags;         /* Flags last received. */
> -
> -    uint32_t rmt_disc;            /* bfd.RemoteDiscr. */
> -
> -    uint8_t eth_dst[ETH_ADDR_LEN];/* Ethernet destination address. */
> -    bool eth_dst_set;             /* 'eth_dst' set through database. */
> -
> -    ovs_be32 ip_src;              /* IPv4 source address. */
> -    ovs_be32 ip_dst;              /* IPv4 destination address. */
> -
> -    uint16_t udp_src;             /* UDP source port. */
> -
> -    /* All timers in milliseconds. */
> -    long long int rmt_min_rx;     /* bfd.RemoteMinRxInterval. */
> -    long long int rmt_min_tx;     /* Remote minimum TX interval. */
> -
> -    long long int cfg_min_tx;     /* Configured minimum TX rate. */
> -    long long int cfg_min_rx;     /* Configured required minimum RX rate.
> */
> -    long long int poll_min_tx;    /* Min TX negotating in a poll
> sequence. */
> -    long long int poll_min_rx;    /* Min RX negotating in a poll
> sequence. */
> -    long long int min_tx;         /* bfd.DesiredMinTxInterval. */
> -    long long int min_rx;         /* bfd.RequiredMinRxInterval. */
> -
> -    long long int last_tx;        /* Last TX time. */
> -    long long int next_tx;        /* Next TX time. */
> -    long long int detect_time;    /* RFC 5880 6.8.4 Detection time. */
> -
> -    bool last_forwarding;         /* Last calculation of forwarding flag.
> */
> -    int forwarding_override;      /* Manual override of 'forwarding'
> status. */
> -
> -    atomic_bool check_tnl_key;    /* Verify tunnel key of inbound
> packets? */
> -    struct ovs_refcount ref_cnt;
> -
> -    /* When forward_if_rx is true, bfd_forwarding() will return
> -     * true as long as there are incoming packets received.
> -     * Note, forwarding_override still has higher priority. */
> -    bool forwarding_if_rx;
> -    long long int forwarding_if_rx_detect_time;
> -
> -    /* BFD decay related variables. */
> -    bool in_decay;                /* True when bfd is in decay. */
> -    int decay_min_rx;             /* min_rx is set to decay_min_rx when */
> -                                  /* in decay. */
> -    int decay_rx_ctl;             /* Count bfd packets received within
> decay */
> -                                  /* detect interval. */
> -    uint64_t decay_rx_packets;    /* Packets received by 'netdev'. */
> -    long long int decay_detect_time; /* Decay detection time. */
> -
> -    uint64_t flap_count;          /* Counts bfd forwarding flaps. */
> -};
> -
> -static struct ovs_mutex mutex = OVS_MUTEX_INITIALIZER;
> -static struct hmap all_bfds__ = HMAP_INITIALIZER(&all_bfds__);
> -static struct hmap *const all_bfds OVS_GUARDED_BY(mutex) = &all_bfds__;
> -
> -static bool bfd_lookup_ip(const char *host_name, struct in_addr *)
> -    OVS_REQUIRES(mutex);
> -static bool bfd_forwarding__(struct bfd *) OVS_REQUIRES(mutex);
> -static bool bfd_in_poll(const struct bfd *) OVS_REQUIRES(mutex);
> -static void bfd_poll(struct bfd *bfd) OVS_REQUIRES(mutex);
> -static const char *bfd_diag_str(enum diag) OVS_REQUIRES(mutex);
> -static const char *bfd_state_str(enum state) OVS_REQUIRES(mutex);
> -static long long int bfd_min_tx(const struct bfd *) OVS_REQUIRES(mutex);
> -static long long int bfd_tx_interval(const struct bfd *)
> -    OVS_REQUIRES(mutex);
> -static long long int bfd_rx_interval(const struct bfd *)
> -    OVS_REQUIRES(mutex);
> -static void bfd_set_next_tx(struct bfd *) OVS_REQUIRES(mutex);
> -static void bfd_set_state(struct bfd *, enum state, enum diag)
> -    OVS_REQUIRES(mutex);
> -static uint32_t generate_discriminator(void) OVS_REQUIRES(mutex);
> -static void bfd_put_details(struct ds *, const struct bfd *)
> -    OVS_REQUIRES(mutex);
> -static uint64_t bfd_rx_packets(const struct bfd *) OVS_REQUIRES(mutex);
> -static void bfd_try_decay(struct bfd *) OVS_REQUIRES(mutex);
> -static void bfd_decay_update(struct bfd *) OVS_REQUIRES(mutex);
> -
> -static void bfd_forwarding_if_rx_update(struct bfd *) OVS_REQUIRES(mutex);
> -static void bfd_unixctl_show(struct unixctl_conn *, int argc,
> -                             const char *argv[], void *aux OVS_UNUSED);
> -static void bfd_unixctl_set_forwarding_override(struct unixctl_conn *,
> -                                                int argc, const char
> *argv[],
> -                                                void *aux OVS_UNUSED);
> -static void log_msg(enum vlog_level, const struct msg *, const char
> *message,
> -                    const struct bfd *) OVS_REQUIRES(mutex);
> -
> -static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(20, 20);
> -
> -/* Returns true if the interface on which 'bfd' is running may be used to
> - * forward traffic according to the BFD session state. */
> -bool
> -bfd_forwarding(struct bfd *bfd) OVS_EXCLUDED(mutex)
> +#include <inttypes.h>
> +#include <limits.h>
> +#include <stdlib.h>
> +#include <string.h>
> +
> +#define MAX(X, Y) ((X) > (Y) ? (X) : (Y))
> +#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
> +
> +
> +static long long int
> +bfd_min_tx(const struct bfd *bfd)
>  {
> -    bool ret;
> +    /* RFC 5880 Section 6.8.3
> +     * When bfd.SessionState is not Up, the system MUST set
> +     * bfd.DesiredMinTxInterval to a value of not less than one second
> +     * (1,000,000 microseconds).  This is intended to ensure that the
> +     * bandwidth consumed by BFD sessions that are not Up is negligible,
> +     * particularly in the case where a neighbor may not be running BFD.
> */
> +    return (bfd->state == STATE_UP ? bfd->min_tx
> +            : MAX(bfd->min_tx, 1000));
> +}
>
> -    ovs_mutex_lock(&mutex);
> -    ret = bfd_forwarding__(bfd);
> -    ovs_mutex_unlock(&mutex);
> -    return ret;
> +static long long int
> +bfd_tx_interval(const struct bfd *bfd)
> +{
> +    long long int interval = bfd_min_tx(bfd);
> +    return MAX(interval, bfd->rmt_min_rx);
>  }
>
> -/* When forwarding_if_rx is enabled, if there are packets received,
> - * updates forwarding_if_rx_detect_time. */
> -void
> -bfd_account_rx(struct bfd *bfd, const struct dpif_flow_stats *stats)
> +static long long int
> +bfd_rx_interval(const struct bfd *bfd)
> +{
> +    return MAX(bfd->min_rx, bfd->rmt_min_tx);
> +}
> +
> +static void
> +bfd_set_next_tx(struct bfd *bfd)
>  {
> -    if (stats->n_packets && bfd->forwarding_if_rx) {
> -        ovs_mutex_lock(&mutex);
> -        bfd_forwarding__(bfd);
> -        bfd_forwarding_if_rx_update(bfd);
> -        bfd_forwarding__(bfd);
> -        ovs_mutex_unlock(&mutex);
> +    long long int interval = bfd_tx_interval(bfd);
> +    interval -= interval * (bfd_get_random() % 26) / 100;
> +    bfd->next_tx = bfd->last_tx + interval;
> +}
> +
> +
> +static bool
> +bfd_forwarding__(const struct bfd *bfd, long long int now)
> +{
> +    bool should_forward = false;
> +
> +    if (bfd->forwarding_override) {
> +        return bfd->forwarding_override == 1;
> +    }
> +
> +    if (bfd->forward_if_rx_interval) {
> +        /* The first time after forward_if_rx is enabled. */
> +        if (!bfd->forward_if_rx_detect_time) {
> +            should_forward = bfd->state == STATE_UP ? true : false;
> +        } else {
> +            should_forward = bfd->forward_if_rx_detect_time > now;
> +        }
>      }
> +
> +    return (bfd->state == STATE_UP
> +            || (bfd->forward_if_rx_interval && should_forward))
> +           && bfd->rmt_diag != DIAG_PATH_DOWN
> +           && bfd->rmt_diag != DIAG_CPATH_DOWN
> +           && bfd->rmt_diag != DIAG_RCPATH_DOWN;
>  }
>
> -/* Returns a 'smap' of key value pairs representing the status of 'bfd'
> - * intended for the OVS database. */
> -void
> -bfd_get_status(const struct bfd *bfd, struct smap *smap)
> -    OVS_EXCLUDED(mutex)
> +/* If there is packet received, sets the 'forward_if_rx_detect_time'
> + * to MAX('forward_if_rx_interval', 'rx_int') away from now. */
> +static void
> +bfd_forward_if_rx(struct bfd *bfd, long long int now)
>  {
> -    ovs_mutex_lock(&mutex);
> -    smap_add(smap, "forwarding",
> -             bfd_forwarding__(CONST_CAST(struct bfd *, bfd))
> -             ? "true" : "false");
> -    smap_add(smap, "state", bfd_state_str(bfd->state));
> -    smap_add(smap, "diagnostic", bfd_diag_str(bfd->diag));
> -    smap_add_format(smap, "flap_count", "%"PRIu64, bfd->flap_count);
> -
> -    if (bfd->state != STATE_DOWN) {
> -        smap_add(smap, "remote_state", bfd_state_str(bfd->rmt_state));
> -        smap_add(smap, "remote_diagnostic", bfd_diag_str(bfd->rmt_diag));
> +    if (bfd->forward_if_rx_data && bfd->forward_if_rx_interval) {
> +        uint32_t rx_int = bfd->mult * bfd_rx_interval(bfd);
> +
> +        bfd->forward_if_rx_detect_time = MAX(bfd->forward_if_rx_interval,
> +                                             rx_int) + now;
> +        bfd->forward_if_rx_data = false;
>      }
> -    ovs_mutex_unlock(&mutex);
>  }
>
> -/* Initializes, destroys, or reconfigures the BFD session 'bfd' (named
> 'name'),
> - * according to the database configuration contained in 'cfg'.  Takes
> ownership
> - * of 'bfd', which may be NULL.  Returns a BFD object which may be used
> as a
> - * handle for the session, or NULL if BFD is not enabled according to
> 'cfg'.
> - * Also returns NULL if cfg is NULL. */
> -struct bfd *
> -bfd_configure(struct bfd *bfd, const char *name, const struct smap *cfg,
> -              struct netdev *netdev) OVS_EXCLUDED(mutex)
> +/* Increments the 'flap_count' if there is a change in the
> + * forwarding flag value. */
> +static void
> +bfd_check_forwarding_flap(struct bfd *bfd, long long int now)
>  {
> -    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
> -    static atomic_uint16_t udp_src = ATOMIC_VAR_INIT(0);
> +    bool last_forwarding = bfd->last_forwarding;
>
> -    int decay_min_rx;
> -    long long int min_tx, min_rx;
> -    bool need_poll = false;
> -    bool cfg_min_rx_changed = false;
> -    bool cpath_down, forwarding_if_rx;
> -    const char *hwaddr, *ip_src, *ip_dst;
> -    struct in_addr in_addr;
> -    uint8_t ea[ETH_ADDR_LEN];
> -
> -    if (ovsthread_once_start(&once)) {
> -        unixctl_command_register("bfd/show", "[interface]", 0, 1,
> -                                 bfd_unixctl_show, NULL);
> -        unixctl_command_register("bfd/set-forwarding",
> -                                 "[interface] normal|false|true", 1, 2,
> -                                 bfd_unixctl_set_forwarding_override,
> NULL);
> -        ovsthread_once_done(&once);
> +    bfd->last_forwarding = bfd_forwarding__(bfd, now);
> +    if (bfd->last_forwarding != last_forwarding) {
> +        bfd->flap_count++;
>      }
> +}
>
> -    if (!cfg || !smap_get_bool(cfg, "enable", false)) {
> -        bfd_unref(bfd);
> -        return NULL;
> +/* Decays the 'bfd->min_rx' to 'bfd->decay_min_rx' when number of packets
> + * received during the 'decay_min_rx' interval is less than two time
> + * number of BFD control packets expected to be received. */
> +static void
> +bfd_try_decay(struct bfd *bfd, long long int now)
> +{
> +    if (bfd->state == STATE_UP && bfd->decay_min_rx
> +        && now >= bfd->decay_detect_time
> +        && bfd->decay_min_rx > bfd->cfg_min_rx) {
> +        uint32_t expect_rx = 2 * (bfd->decay_min_rx / bfd->min_rx + 1);
> +
> +        bfd->in_decay = bfd->decay_rx_count < expect_rx;
> +        bfd->decay_detect_time = bfd->decay_min_rx + now;
> +        bfd->decay_rx_count = 0;
>      }
> +}
>
> -    ovs_mutex_lock(&mutex);
> -    if (!bfd) {
> -        bfd = xzalloc(sizeof *bfd);
> -        bfd->name = xstrdup(name);
> -        bfd->forwarding_override = -1;
> -        bfd->disc = generate_discriminator();
> -        hmap_insert(all_bfds, &bfd->node, bfd->disc);
> -
> -        bfd->diag = DIAG_NONE;
> -        bfd->min_tx = 1000;
> -        bfd->mult = 3;
> -        ovs_refcount_init(&bfd->ref_cnt);
> -        bfd->netdev = netdev_ref(netdev);
> -        bfd->rx_packets = bfd_rx_packets(bfd);
> -        bfd->in_decay = false;
> -        bfd->flap_count = 0;
> +static void
> +bfd_set_state(struct bfd *bfd, enum bfd_state state, enum bfd_diag diag,
> +              long long int now)
> +{
> +    if (bfd->cpath_down) {
> +        diag = DIAG_CPATH_DOWN;
> +    }
> +
> +    if (bfd->state != state || bfd->diag != diag) {
> +        bfd_log(BFD_LOG_INFO, "%s: BFD state change: %s->%s"
> +                " \"%s\"->\"%s\".", bfd->name,
> bfd_state_to_str(bfd->state),
> +                bfd_state_to_str(state), bfd_diag_to_str(bfd->diag),
> +                bfd_diag_to_str(diag));
> +
> +        bfd->state = state;
> +        bfd->diag = diag;
> +
> +        if (bfd->state <= STATE_DOWN) {
> +            bfd->rmt_state = STATE_DOWN;
> +            bfd->rmt_diag = DIAG_NONE;
> +            bfd->rmt_min_rx = 1;
> +            bfd->rmt_flags = 0;
> +            bfd->rmt_disc = 0;
> +            bfd->rmt_min_tx = 0;
> +        }
> +
> +        if (bfd->state != STATE_UP && bfd->decay_min_rx) {
> +            bfd->min_rx = bfd->cfg_min_rx;
> +            bfd->in_decay = false;
> +            bfd->decay_rx_count = UINT32_MAX;
> +        }
> +    }
> +
> +    bfd_check_forwarding_flap(bfd, now);
> +}
> +
> +static bool
> +bfd_in_poll(const struct bfd *bfd)
> +{
> +    return (bfd->flags & FLAG_POLL) != 0;
> +}
>
> -        /* RFC 5881 section 4
> -         * The source port MUST be in the range 49152 through 65535.  The
> same
> -         * UDP source port number MUST be used for all BFD Control packets
> -         * associated with a particular session.  The source port number
> SHOULD
> -         * be unique among all BFD sessions on the system. */
> -        atomic_add(&udp_src, 1, &bfd->udp_src);
> -        bfd->udp_src = (bfd->udp_src % 16384) + 49152;
> +static void
> +bfd_poll(struct bfd *bfd)
> +{
> +    if (bfd->state > STATE_DOWN && !bfd_in_poll(bfd)
> +        && !(bfd->flags & FLAG_FINAL)) {
> +        bfd->poll_min_tx = bfd->cfg_min_tx;
> +        bfd->poll_min_rx = bfd->in_decay ? bfd->decay_min_rx :
> bfd->cfg_min_rx;
> +        bfd->flags |= FLAG_POLL;
> +        bfd->next_tx = 0;
> +        bfd_log(BFD_LOG_INFO, "%s: Initiating poll sequence", bfd->name);
> +    }
> +}
> +
> +static void
> +bfd_log_msg(enum bfd_log_levels level, char *message, const struct
> bfd_msg *p,
> +            const struct bfd *bfd)
> +{
> +    bfd_log(level, "%s: %s."
> +                   "\n\tvers:%"PRIu8" diag:\"%s\" state:%s mult:%"PRIu8
> +                   " length:%"PRIu8
> +                   "\n\tflags: %s"
> +                   "\n\tmy_disc:0x%"PRIx32" your_disc:0x%"PRIx32
> +                   "\n\tmin_tx:%"PRIu32"us (%"PRIu32"ms)"
> +                   "\n\tmin_rx:%"PRIu32"us (%"PRIu32"ms)"
> +                   "\n\tmin_rx_echo:%"PRIu32"us (%"PRIu32"ms)",
> +                   bfd->name, message, p->vers_diag >> VERS_SHIFT,
> +                   bfd_diag_to_str(p->vers_diag & DIAG_MASK),
> +                   bfd_state_to_str(p->flags & STATE_MASK),
> +                   p->mult, p->length,
> +                   bfd_flag_to_str(p->flags & FLAGS_MASK),
> +                   ntohl(p->my_disc), ntohl(p->your_disc),
> +                   ntohl(p->min_tx), ntohl(p->min_tx) / 1000,
> +                   ntohl(p->min_rx), ntohl(p->min_rx) / 1000,
> +                   ntohl(p->min_rx_echo), ntohl(p->min_rx_echo) / 1000);
> +}
> +
> +
> +/* Configures 'bfd' using the 'setting'.  Returns 0 if successful, a
> positive
> + * error number otherwise. */
> +enum bfd_error
> +bfd_configure(struct bfd *bfd, const struct bfd_setting *setting)
> +{
> +    uint32_t min_tx, min_rx;
> +    uint8_t mult;
> +    bool min_rx_changed = false;
> +    bool need_poll = false;
> +
> +    if (!bfd || !setting) {
> +        return BFD_EINVAL;
> +    }
> +
> +    bfd->name = setting->name;
> +
> +    if (bfd->state == STATE_ADMIN_DOWN) {
> +        bfd_set_state(bfd, STATE_DOWN, DIAG_NONE, 0);
> +    }
>
> -        bfd_set_state(bfd, STATE_DOWN, DIAG_NONE);
> +    if (bfd->disc != setting->disc) {
> +        bfd->disc = setting->disc;
> +    }
>
> -        memcpy(bfd->eth_dst, eth_addr_bfd, ETH_ADDR_LEN);
> +    mult = MAX(setting->mult, 3);
> +    if (bfd->mult != mult) {
> +        bfd->mult = mult;
>      }
>
> -    atomic_store(&bfd->check_tnl_key,
> -                 smap_get_bool(cfg, "check_tnl_key", false));
> -    min_tx = smap_get_int(cfg, "min_tx", 100);
> -    min_tx = MAX(min_tx, 100);
> +    min_tx = MAX(setting->min_tx, 100);
>      if (bfd->cfg_min_tx != min_tx) {
>          bfd->cfg_min_tx = min_tx;
>          if (bfd->state != STATE_UP
> @@ -379,220 +249,187 @@ bfd_configure(struct bfd *bfd, const char *name,
> const struct smap *cfg,
>          need_poll = true;
>      }
>
> -    min_rx = smap_get_int(cfg, "min_rx", 1000);
> -    min_rx = MAX(min_rx, 100);
> +    min_rx = MAX(setting->min_rx, 100);
>      if (bfd->cfg_min_rx != min_rx) {
>          bfd->cfg_min_rx = min_rx;
>          if (bfd->state != STATE_UP
>              || (!bfd_in_poll(bfd) && bfd->cfg_min_rx > bfd->min_rx)) {
>              bfd->min_rx = bfd->cfg_min_rx;
>          }
> -        cfg_min_rx_changed = true;
> -        need_poll = true;
> -    }
> -
> -    decay_min_rx = smap_get_int(cfg, "decay_min_rx", 0);
> -    if (bfd->decay_min_rx != decay_min_rx || cfg_min_rx_changed) {
> -        if (decay_min_rx > 0 && decay_min_rx < bfd->cfg_min_rx) {
> -            VLOG_WARN("%s: decay_min_rx cannot be less than %lld ms",
> -                      bfd->name, bfd->cfg_min_rx);
> -            bfd->decay_min_rx = 0;
> -        } else {
> -            bfd->decay_min_rx = decay_min_rx;
> -        }
> -        /* Resets decay. */
> -        bfd->in_decay = false;
> -        bfd_decay_update(bfd);
> +        min_rx_changed = true;
>          need_poll = true;
>      }
>
> -    cpath_down = smap_get_bool(cfg, "cpath_down", false);
> -    if (bfd->cpath_down != cpath_down) {
> -        bfd->cpath_down = cpath_down;
> -        bfd_set_state(bfd, bfd->state, DIAG_NONE);
> +    if (bfd->cpath_down != setting->cpath_down) {
> +        bfd->cpath_down = setting->cpath_down;
> +        bfd_set_state(bfd, bfd->state, DIAG_NONE, LLONG_MAX);
>          need_poll = true;
>      }
>
> -    hwaddr = smap_get(cfg, "bfd_dst_mac");
> -    if (hwaddr && eth_addr_from_string(hwaddr, ea) &&
> !eth_addr_is_zero(ea)) {
> -        memcpy(bfd->eth_dst, ea, ETH_ADDR_LEN);
> -        bfd->eth_dst_set = true;
> -    } else if (bfd->eth_dst_set) {
> -        memcpy(bfd->eth_dst, eth_addr_bfd, ETH_ADDR_LEN);
> -        bfd->eth_dst_set = false;
> -    }
> -
> -    ip_src = smap_get(cfg, "bfd_src_ip");
> -    if (ip_src && bfd_lookup_ip(ip_src, &in_addr)) {
> -        memcpy(&bfd->ip_src, &in_addr, sizeof in_addr);
> -    } else {
> -        bfd->ip_src = htonl(0xA9FE0100); /* 169.254.1.0. */
> +    if (bfd->forwarding_override != setting->forwarding_override) {
> +        bfd->forwarding_override = setting->forwarding_override;
>      }
>
> -    ip_dst = smap_get(cfg, "bfd_dst_ip");
> -    if (ip_dst && bfd_lookup_ip(ip_dst, &in_addr)) {
> -        memcpy(&bfd->ip_dst, &in_addr, sizeof in_addr);
> -    } else {
> -        bfd->ip_dst = htonl(0xA9FE0101); /* 169.254.1.1. */
> +    if (bfd->forward_if_rx_interval != setting->forward_if_rx_interval) {
> +        bfd->forward_if_rx_interval = setting->forward_if_rx_interval;
> +        bfd->forward_if_rx_detect_time = 0;
>      }
>
> -    forwarding_if_rx = smap_get_bool(cfg, "forwarding_if_rx", false);
> -    if (bfd->forwarding_if_rx != forwarding_if_rx) {
> -        bfd->forwarding_if_rx = forwarding_if_rx;
> -        if (bfd->state == STATE_UP && bfd->forwarding_if_rx) {
> -            bfd_forwarding_if_rx_update(bfd);
> -        } else {
> -            bfd->forwarding_if_rx_detect_time = 0;
> -        }
> +    if (bfd->decay_min_rx != setting->decay_min_rx || min_rx_changed) {
> +        bfd->decay_min_rx = setting->decay_min_rx;
> +        bfd->in_decay = false;
> +        bfd->decay_rx_count = UINT32_MAX;
> +        bfd->decay_detect_time = 0;
> +        need_poll = true;
>      }
>
>      if (need_poll) {
>          bfd_poll(bfd);
>      }
> -    ovs_mutex_unlock(&mutex);
> -    return bfd;
> -}
>
> -struct bfd *
> -bfd_ref(const struct bfd *bfd_)
> -{
> -    struct bfd *bfd = CONST_CAST(struct bfd *, bfd_);
> -    if (bfd) {
> -        ovs_refcount_ref(&bfd->ref_cnt);
> -    }
> -    return bfd;
> +    return BFD_PASS;
>  }
>
> -void
> -bfd_unref(struct bfd *bfd) OVS_EXCLUDED(mutex)
> -{
> -    if (bfd && ovs_refcount_unref(&bfd->ref_cnt) == 1) {
> -        ovs_mutex_lock(&mutex);
> -        hmap_remove(all_bfds, &bfd->node);
> -        netdev_close(bfd->netdev);
> -        ovs_refcount_destroy(&bfd->ref_cnt);
> -        free(bfd->name);
> -        free(bfd);
> -        ovs_mutex_unlock(&mutex);
> -    }
> -}
> -
> -void
> -bfd_wait(const struct bfd *bfd) OVS_EXCLUDED(mutex)
> -{
> -    poll_timer_wait_until(bfd_wake_time(bfd));
> -}
> -
> -/* Returns the next wake up time. */
> +/* Returns the wakeup time of the BFD session. */
>  long long int
> -bfd_wake_time(const struct bfd *bfd) OVS_EXCLUDED(mutex)
> +bfd_wait(const struct bfd *bfd)
>  {
> -    long long int retval;
> +    long long int ret;
>
>      if (!bfd) {
>          return LLONG_MAX;
>      }
>
> -    ovs_mutex_lock(&mutex);
>      if (bfd->flags & FLAG_FINAL) {
> -        retval = 0;
> +        ret = 0;
>      } else {
> -        retval = bfd->next_tx;
> +        ret = bfd->next_tx;
>          if (bfd->state > STATE_DOWN) {
> -            retval = MIN(bfd->detect_time, retval);
> +            ret = MIN(bfd->detect_time, ret);
> +        }
> +        if (bfd->state == STATE_UP && bfd->decay_min_rx) {
> +            ret = MIN(bfd->decay_detect_time, ret);
>          }
>      }
> -    ovs_mutex_unlock(&mutex);
> -    return retval;
> +
> +    return ret;
>  }
>
> +/* Updates the BFD sessions status.  Checks decay and forward_if_rx.
> + * Initiates the POLL sequence if needed. */
>  void
> -bfd_run(struct bfd *bfd) OVS_EXCLUDED(mutex)
> +bfd_run(struct bfd *bfd, long long int now)
>  {
> -    long long int now;
> -    bool old_in_decay;
> +    bool old;
>
> -    ovs_mutex_lock(&mutex);
> -    now = time_msec();
> -    old_in_decay = bfd->in_decay;
> +    if (!bfd) {
> +        return;
> +    }
>
>      if (bfd->state > STATE_DOWN && now >= bfd->detect_time) {
> -        bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED);
> +        bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED, now);
>      }
> -    bfd_forwarding__(bfd);
>
> -    /* Decay may only happen when state is STATE_UP, bfd->decay_min_rx is
> -     * configured, and decay_detect_time is reached. */
> -    if (bfd->state == STATE_UP && bfd->decay_min_rx > 0
> -        && now >= bfd->decay_detect_time) {
> -        bfd_try_decay(bfd);
> -    }
> +    old = bfd->in_decay;
> +    bfd_try_decay(bfd, now);
> +
> +    bfd_forward_if_rx(bfd, now);
> +    bfd_check_forwarding_flap(bfd, now);
>
>      if (bfd->min_tx != bfd->cfg_min_tx
> -        || (bfd->min_rx != bfd->cfg_min_rx && bfd->min_rx !=
> bfd->decay_min_rx)
> -        || bfd->in_decay != old_in_decay) {
> +        || (!bfd->in_decay && bfd->min_rx != bfd->cfg_min_rx)
> +        || (bfd->in_decay && bfd->min_rx != bfd->decay_min_rx)
> +        || bfd->in_decay != old) {
>          bfd_poll(bfd);
>      }
> -    ovs_mutex_unlock(&mutex);
>  }
>
> +/* Queries the 'bfd''s status, the function will fill in the
> + * 'struct bfd_status'. */
> +void
> +bfd_get_status(const struct bfd *bfd, struct bfd_status *s)
> +{
> +    if (!bfd || !s) {
> +        return;
> +    }
> +
> +    s->forwarding = bfd->last_forwarding;
> +    s->mult = bfd->mult;
> +    s->cpath_down = bfd->cpath_down;
> +    s->tx_interval = bfd_tx_interval(bfd);
> +    s->rx_interval = bfd_rx_interval(bfd);
> +
> +    s->local_disc = bfd->disc;
> +    s->local_min_tx = bfd_min_tx(bfd);
> +    s->local_min_rx = bfd->min_rx;
> +    s->local_flags = bfd->flags;
> +    s->local_state = bfd->state;
> +    s->local_diag = bfd->diag;
> +    s->detect_time = bfd->detect_time;
> +    s->next_tx = bfd->next_tx;
> +    s->last_tx = bfd->last_tx;
> +
> +    s->rmt_disc = bfd->rmt_disc;
> +    s->rmt_min_tx = bfd->rmt_min_tx;
> +    s->rmt_min_rx = bfd->rmt_min_rx;
> +    s->rmt_flags = bfd->rmt_flags;
> +    s->rmt_state = bfd->rmt_state;
> +    s->rmt_diag = bfd->rmt_diag;
> +
> +    s->flap_count = bfd->flap_count;
> +}
> +
> +/* Returns true if the interface on which BFD is running may be used to
> + * forward traffic according to the BFD session state.  'now' is the
> + * current time in milliseconds. */
>  bool
> -bfd_should_send_packet(const struct bfd *bfd) OVS_EXCLUDED(mutex)
> +bfd_forwarding(const struct bfd *bfd, long long int now)
>  {
> -    bool ret;
> -    ovs_mutex_lock(&mutex);
> -    ret = bfd->flags & FLAG_FINAL || time_msec() >= bfd->next_tx;
> -    ovs_mutex_unlock(&mutex);
> -    return ret;
> +    return bfd_forwarding__(bfd, now);
>  }
>
> +/* Sets the corresponding flags to indicate that packet
> + * is received from this monitored interface. */
>  void
> -bfd_put_packet(struct bfd *bfd, struct ofpbuf *p,
> -               uint8_t eth_src[ETH_ADDR_LEN]) OVS_EXCLUDED(mutex)
> +bfd_account_rx(struct bfd *bfd, uint32_t n_pkt)
> +{
> +    if (bfd->forward_if_rx_interval && n_pkt) {
> +        bfd->forward_if_rx_data = true;
> +    }
> +
> +    if (bfd->decay_min_rx && bfd->decay_rx_count != UINT32_MAX) {
> +        bfd->decay_rx_count += n_pkt;
> +    }
> +}
> +
> +/* For send/recv BFD control packets. */
> +/* Returns true if the BFD control packet should be sent for this BFD
> + * session.  e.g. tx timeout or POLL flag is on. */
> +bool
> +bfd_should_send_packet(const struct bfd *bfd, long long int now)
> +{
> +    return bfd->flags & FLAG_FINAL || now >= bfd->next_tx;
> +}
> +
> +/* Constructs the BFD control packet in payload.  This function assumes
> that
> + * the payload is properly aligned. */
> +enum bfd_error
> +bfd_put_packet(struct bfd *bfd, void *p, size_t len, long long int now)
>  {
>      long long int min_tx, min_rx;
> -    struct udp_header *udp;
> -    struct eth_header *eth;
> -    struct ip_header *ip;
> -    struct msg *msg;
> -
> -    ovs_mutex_lock(&mutex);
> -    if (bfd->next_tx) {
> -        long long int delay = time_msec() - bfd->next_tx;
> -        long long int interval = bfd_tx_interval(bfd);
> -        if (delay > interval * 3 / 2) {
> -            VLOG_INFO("%s: long delay of %lldms (expected %lldms) sending
> BFD"
> -                      " control message", bfd->name, delay, interval);
> -        }
> +    struct bfd_msg *msg = p;
> +
> +    if (!bfd || !p || len < BFD_PACKET_LEN) {
> +        return BFD_EINVAL;
>      }
>
>      /* RFC 5880 Section 6.5
>       * A BFD Control packet MUST NOT have both the Poll (P) and Final (F)
> bits
>       * set. */
> -    ovs_assert(!(bfd->flags & FLAG_POLL) || !(bfd->flags & FLAG_FINAL));
> -
> -    ofpbuf_reserve(p, 2); /* Properly align after the ethernet header. */
> -    eth = ofpbuf_put_uninit(p, sizeof *eth);
> -    memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
> -    memcpy(eth->eth_dst, bfd->eth_dst, ETH_ADDR_LEN);
> -    eth->eth_type = htons(ETH_TYPE_IP);
> -
> -    ip = ofpbuf_put_zeros(p, sizeof *ip);
> -    ip->ip_ihl_ver = IP_IHL_VER(5, 4);
> -    ip->ip_tot_len = htons(sizeof *ip + sizeof *udp + sizeof *msg);
> -    ip->ip_ttl = MAXTTL;
> -    ip->ip_tos = IPTOS_LOWDELAY | IPTOS_THROUGHPUT;
> -    ip->ip_proto = IPPROTO_UDP;
> -    put_16aligned_be32(&ip->ip_src, bfd->ip_src);
> -    put_16aligned_be32(&ip->ip_dst, bfd->ip_dst);
> -    ip->ip_csum = csum(ip, sizeof *ip);
> -
> -    udp = ofpbuf_put_zeros(p, sizeof *udp);
> -    udp->udp_src = htons(bfd->udp_src);
> -    udp->udp_dst = htons(BFD_DEST_PORT);
> -    udp->udp_len = htons(sizeof *udp + sizeof *msg);
> -
> -    msg = ofpbuf_put_uninit(p, sizeof *msg);
> +    if ((bfd->flags & FLAG_POLL) && (bfd->flags & FLAG_FINAL)) {
> +        return BFD_EPOLL;
> +    }
> +
>      msg->vers_diag = (BFD_VERSION << 5) | bfd->diag;
>      msg->flags = (bfd->state & STATE_MASK) | bfd->flags;
>
> @@ -615,69 +452,40 @@ bfd_put_packet(struct bfd *bfd, struct ofpbuf *p,
>
>      bfd->flags &= ~FLAG_FINAL;
>
> -    log_msg(VLL_DBG, msg, "Sending BFD Message", bfd);
> -
> -    bfd->last_tx = time_msec();
> +    bfd->last_tx = now;
>      bfd_set_next_tx(bfd);
> -    ovs_mutex_unlock(&mutex);
> +
> +    bfd_log(BFD_LOG_DBG, "%s: Sending BFD Message", bfd->name);
> +    return BFD_PASS;
>  }
>
> +/* Given the packet header entries, check if the packet is BFD control
> + * packet. */
>  bool
> -bfd_should_process_flow(const struct bfd *bfd_, const struct flow *flow,
> -                        struct flow_wildcards *wc)
> +bfd_should_process_packet(const __be16 eth_type, const uint8_t ip_proto,
> +                          const __be16 udp_dst)
>  {
> -    struct bfd *bfd = CONST_CAST(struct bfd *, bfd_);
> -    bool check_tnl_key;
> -
> -    memset(&wc->masks.dl_dst, 0xff, sizeof wc->masks.dl_dst);
> -    if (bfd->eth_dst_set && memcmp(bfd->eth_dst, flow->dl_dst,
> ETH_ADDR_LEN)) {
> -        return false;
> -    }
> -
> -    memset(&wc->masks.nw_proto, 0xff, sizeof wc->masks.nw_proto);
> -    memset(&wc->masks.tp_dst, 0xff, sizeof wc->masks.tp_dst);
> -
> -    atomic_read(&bfd->check_tnl_key, &check_tnl_key);
> -    if (check_tnl_key) {
> -        memset(&wc->masks.tunnel.tun_id, 0xff, sizeof
> wc->masks.tunnel.tun_id);
> -    }
> -    return (flow->dl_type == htons(ETH_TYPE_IP)
> -            && flow->nw_proto == IPPROTO_UDP
> -            && flow->tp_dst == htons(BFD_DEST_PORT)
> -            && (!check_tnl_key || flow->tunnel.tun_id == htonll(0)));
> +    return (eth_type == htons(0x0800) /* IP. */
> +            && ip_proto == 17         /* UDP. */
> +            && udp_dst == htons(BFD_DEST_PORT));
>  }
>
> -void
> -bfd_process_packet(struct bfd *bfd, const struct flow *flow,
> -                   const struct ofpbuf *p) OVS_EXCLUDED(mutex)
> +/* Processes the BFD control packet in payload 'p'.  The payload length is
> + * provided. */
> +enum bfd_error
> +bfd_process_packet(struct bfd *bfd, void *p, size_t len, long long int
> now)
>  {
>      uint32_t rmt_min_rx, pkt_your_disc;
> -    enum state rmt_state;
> -    enum flags flags;
> +    enum bfd_state rmt_state;
> +    enum bfd_flags flags;
>      uint8_t version;
> -    struct msg *msg;
> -
> -    /* This function is designed to follow section RFC 5880 6.8.6
> closely. */
> -
> -    ovs_mutex_lock(&mutex);
> -    /* Increments the decay rx counter. */
> -    bfd->decay_rx_ctl++;
> -
> -    bfd_forwarding__(bfd);
> +    struct bfd_msg *msg = p;
>
> -    if (flow->nw_ttl != 255) {
> -        /* XXX Should drop in the kernel to prevent DOS. */
> -        goto out;
> +    if (!bfd || !p || len < BFD_PACKET_LEN) {
> +        return BFD_EINVAL;
>      }
>
> -    msg = ofpbuf_at(p, (uint8_t *)p->l7 - (uint8_t *)p->data,
> BFD_PACKET_LEN);
> -    if (!msg) {
> -        VLOG_INFO_RL(&rl, "%s: Received too-short BFD control message
> (only "
> -                     "%"PRIdPTR" bytes long, at least %d required).",
> -                     bfd->name, (uint8_t *) ofpbuf_tail(p) - (uint8_t *)
> p->l7,
> -                     BFD_PACKET_LEN);
> -        goto out;
> -    }
> +    /* This function is designed to follow section RFC 5880 6.8.6
> closely. */
>
>      /* RFC 5880 Section 6.8.6
>       * If the Length field is greater than the payload of the
> encapsulating
> @@ -692,61 +500,57 @@ bfd_process_packet(struct bfd *bfd, const struct
> flow *flow,
>      rmt_state = msg->flags & STATE_MASK;
>      version = msg->vers_diag >> VERS_SHIFT;
>
> -    log_msg(VLL_DBG, msg, "Received BFD control message", bfd);
> +    bfd_log_msg(BFD_LOG_DBG, "Received BFD control message", p, bfd);
>
>      if (version != BFD_VERSION) {
> -        log_msg(VLL_WARN, msg, "Incorrect version", bfd);
> -        goto out;
> +        bfd_log_msg(BFD_LOG_WARN, "Incorrect version", p, bfd);
> +        goto err;
>      }
>
>      /* Technically this should happen after the length check. We don't
> support
>       * authentication however, so it's simpler to do the check first. */
>      if (flags & FLAG_AUTH) {
> -        log_msg(VLL_WARN, msg, "Authenticated control message with"
> -                   " authentication disabled", bfd);
> -        goto out;
> +        bfd_log_msg(BFD_LOG_WARN, "Authenticated control message with"
> +                " authentication disabled", p, bfd);
> +        goto err;
>      }
>
>      if (msg->length != BFD_PACKET_LEN) {
> -        log_msg(VLL_WARN, msg, "Unexpected length", bfd);
> +        bfd_log_msg(BFD_LOG_WARN, "Unexpected length", p, bfd);
>          if (msg->length < BFD_PACKET_LEN) {
> -            goto out;
> +            goto err;
>          }
>      }
>
>      if (!msg->mult) {
> -        log_msg(VLL_WARN, msg, "Zero multiplier", bfd);
> -        goto out;
> +        bfd_log_msg(BFD_LOG_WARN, "Zero multiplier", p, bfd);
> +        goto err;
>      }
>
>      if (flags & FLAG_MULTIPOINT) {
> -        log_msg(VLL_WARN, msg, "Unsupported multipoint flag", bfd);
> -        goto out;
> +        bfd_log_msg(BFD_LOG_WARN, "Unsupported multipoint flag", p, bfd);
> +        goto err;
>      }
>
>      if (!msg->my_disc) {
> -        log_msg(VLL_WARN, msg, "NULL my_disc", bfd);
> -        goto out;
> +        bfd_log_msg(BFD_LOG_WARN, "NULL my_disc", p, bfd);
> +        goto err;
>      }
>
>      pkt_your_disc = ntohl(msg->your_disc);
>      if (pkt_your_disc) {
>          /* Technically, we should use the your discriminator field to
> figure
>           * out which 'struct bfd' this packet is destined towards.  That
> way a
> -         * bfd session could migrate from one interface to another
> +         * BFD session could migrate from one interface to another
>           * transparently.  This doesn't fit in with the OVS structure very
>           * well, so in this respect, we are not compliant. */
>         if (pkt_your_disc != bfd->disc) {
> -           log_msg(VLL_WARN, msg, "Incorrect your_disc", bfd);
> -           goto out;
> +           bfd_log_msg(BFD_LOG_WARN, "Incorrect your_disc", p, bfd);
> +           goto err;
>         }
>      } else if (rmt_state > STATE_DOWN) {
> -        log_msg(VLL_WARN, msg, "Null your_disc", bfd);
> -        goto out;
> -    }
> -
> -    if (bfd->rmt_state != rmt_state) {
> -        seq_change(connectivity_seq_get());
> +        bfd_log_msg(BFD_LOG_WARN, "Null your_disc", p, bfd);
> +        goto err;
>      }
>
>      bfd->rmt_disc = ntohl(msg->my_disc);
> @@ -758,7 +562,7 @@ bfd_process_packet(struct bfd *bfd, const struct flow
> *flow,
>          bfd->min_tx = bfd->poll_min_tx;
>          bfd->min_rx = bfd->poll_min_rx;
>          bfd->flags &= ~FLAG_POLL;
> -        log_msg(VLL_INFO, msg, "Poll sequence terminated", bfd);
> +        bfd_log_msg(BFD_LOG_INFO, "Poll sequence terminated", p, bfd);
>      }
>
>      if (flags & FLAG_POLL) {
> @@ -777,209 +581,116 @@ bfd_process_packet(struct bfd *bfd, const struct
> flow *flow,
>          if (bfd->next_tx) {
>              bfd_set_next_tx(bfd);
>          }
> -        log_msg(VLL_INFO, msg, "New remote min_rx", bfd);
> +        bfd_log_msg(BFD_LOG_INFO, "New remote min_rx", p, bfd);
>      }
>
>      bfd->rmt_min_tx = MAX(ntohl(msg->min_tx) / 1000, 1);
> -    bfd->detect_time = bfd_rx_interval(bfd) * bfd->mult + time_msec();
> +    bfd->detect_time = bfd_rx_interval(bfd) * bfd->mult + now;
>
>      if (bfd->state == STATE_ADMIN_DOWN) {
> -        VLOG_DBG_RL(&rl, "Administratively down, dropping control
> message.");
> +        bfd_log_msg(BFD_LOG_DBG, "Administratively down, dropping control"
> +                    " message.", p, bfd);
>          goto out;
>      }
>
>      if (rmt_state == STATE_ADMIN_DOWN) {
>          if (bfd->state != STATE_DOWN) {
> -            bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN);
> +            bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN, now);
>          }
>      } else {
>          switch (bfd->state) {
>          case STATE_DOWN:
>              if (rmt_state == STATE_DOWN) {
> -                bfd_set_state(bfd, STATE_INIT, bfd->diag);
> +                bfd_set_state(bfd, STATE_INIT, bfd->diag, now);
>              } else if (rmt_state == STATE_INIT) {
> -                bfd_set_state(bfd, STATE_UP, bfd->diag);
> +                bfd_set_state(bfd, STATE_UP, bfd->diag, now);
>              }
>              break;
>          case STATE_INIT:
>              if (rmt_state > STATE_DOWN) {
> -                bfd_set_state(bfd, STATE_UP, bfd->diag);
> +                bfd_set_state(bfd, STATE_UP, bfd->diag, now);
>              }
>              break;
>          case STATE_UP:
>              if (rmt_state <= STATE_DOWN) {
> -                bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN);
> -                log_msg(VLL_INFO, msg, "Remote signaled STATE_DOWN", bfd);
> +                bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN, now);
> +                bfd_log_msg(BFD_LOG_INFO, "Remote signaled STATE_DOWN",
> +                            p, bfd);
>              }
>              break;
>          case STATE_ADMIN_DOWN:
>          default:
> -            OVS_NOT_REACHED();
> +            break;
>          }
>      }
> -    /* XXX: RFC 5880 Section 6.8.6 Demand mode related calculations here.
> */
>
>  out:
> -    bfd_forwarding__(bfd);
> -    ovs_mutex_unlock(&mutex);
> -}
> -
> -/* Must be called when the netdev owned by 'bfd' should change. */
> -void
> -bfd_set_netdev(struct bfd *bfd, const struct netdev *netdev)
> -    OVS_EXCLUDED(mutex)
> -{
> -    ovs_mutex_lock(&mutex);
> -    if (bfd->netdev != netdev) {
> -        netdev_close(bfd->netdev);
> -        bfd->netdev = netdev_ref(netdev);
> -        if (bfd->decay_min_rx && bfd->state == STATE_UP) {
> -            bfd_decay_update(bfd);
> -        }
> -        if (bfd->forwarding_if_rx && bfd->state == STATE_UP) {
> -            bfd_forwarding_if_rx_update(bfd);
> -        }
> -        bfd->rx_packets = bfd_rx_packets(bfd);
> -    }
> -    ovs_mutex_unlock(&mutex);
> -}
> -
> -
> -/* Updates the forwarding flag.  If override is not configured and
> - * the forwarding flag value changes, increments the flap count.
> - *
> - * Note this function may be called multiple times in a function
> - * (e.g. bfd_account_rx) before and after the bfd state or status
> - * change.  This is to capture any forwarding flag flap. */
> -static bool
> -bfd_forwarding__(struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    long long int time;
> -    bool last_forwarding = bfd->last_forwarding;
> +    return BFD_PASS;
>
> -    if (bfd->forwarding_override != -1) {
> -        return bfd->forwarding_override == 1;
> -    }
> -
> -    time = bfd->forwarding_if_rx_detect_time;
> -    bfd->last_forwarding = (bfd->state == STATE_UP
> -                            || (bfd->forwarding_if_rx && time >
> time_msec()))
> -                            && bfd->rmt_diag != DIAG_PATH_DOWN
> -                            && bfd->rmt_diag != DIAG_CPATH_DOWN
> -                            && bfd->rmt_diag != DIAG_RCPATH_DOWN;
> -    if (bfd->last_forwarding != last_forwarding) {
> -        bfd->flap_count++;
> -        seq_change(connectivity_seq_get());
> -    }
> -    return bfd->last_forwarding;
> +err:
> +    return BFD_EMSG;
>  }
>
>  /* Helpers. */
> -static bool
> -bfd_lookup_ip(const char *host_name, struct in_addr *addr)
> +/* Converts the BFD error code to string.
> + * This function is thread-safe and reentrant. */
> +const char *
> +bfd_error_to_str(enum bfd_error error)
>  {
> -    if (!inet_pton(AF_INET, host_name, addr)) {
> -        VLOG_ERR_RL(&rl, "\"%s\" is not a valid IP address", host_name);
> -        return false;
> +    switch (error) {
> +    case BFD_PASS: return "No Error";
> +    case BFD_EINVAL: return "Invalid Arguments";
> +    case BFD_EPOLL: return "Both POLL And FINAL Set";
> +    case BFD_EMSG: return "Bad Control Packet";
> +    default: return "Not An Error Code";
>      }
> -    return true;
>  }
>
> -static bool
> -bfd_in_poll(const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    return (bfd->flags & FLAG_POLL) != 0;
> -}
> -
> -static void
> -bfd_poll(struct bfd *bfd) OVS_REQUIRES(mutex)
> +/* Per-thread string for parsing the flags. */
> +static bfd_thread_local char flag_str[128];
> +/* Converts the BFD flags to string.
> + * This function is thread-safe if bfd_thread_local is defined.
> + * This function is non-reentrant. */
> +const char *
> +bfd_flag_to_str(enum bfd_flags flags)
>  {
> -    if (bfd->state > STATE_DOWN && !bfd_in_poll(bfd)
> -        && !(bfd->flags & FLAG_FINAL)) {
> -        bfd->poll_min_tx = bfd->cfg_min_tx;
> -        bfd->poll_min_rx = bfd->in_decay ? bfd->decay_min_rx :
> bfd->cfg_min_rx;
> -        bfd->flags |= FLAG_POLL;
> -        bfd->next_tx = 0;
> -        VLOG_INFO_RL(&rl, "%s: Initiating poll sequence", bfd->name);
> -    }
> -}
> -
> -static long long int
> -bfd_min_tx(const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    /* RFC 5880 Section 6.8.3
> -     * When bfd.SessionState is not Up, the system MUST set
> -     * bfd.DesiredMinTxInterval to a value of not less than one second
> -     * (1,000,000 microseconds).  This is intended to ensure that the
> -     * bandwidth consumed by BFD sessions that are not Up is negligible,
> -     * particularly in the case where a neighbor may not be running BFD.
> */
> -    return (bfd->state == STATE_UP ? bfd->min_tx : MAX(bfd->min_tx,
> 1000));
> -}
> -
> -static long long int
> -bfd_tx_interval(const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    long long int interval = bfd_min_tx(bfd);
> -    return MAX(interval, bfd->rmt_min_rx);
> -}
> -
> -static long long int
> -bfd_rx_interval(const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    return MAX(bfd->min_rx, bfd->rmt_min_tx);
> -}
> -
> -static void
> -bfd_set_next_tx(struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    long long int interval = bfd_tx_interval(bfd);
> -    interval -= interval * random_range(26) / 100;
> -    bfd->next_tx = bfd->last_tx + interval;
> -}
> -
> -static const char *
> -bfd_flag_str(enum flags flags)
> -{
> -    struct ds ds = DS_EMPTY_INITIALIZER;
> -    static char flag_str[128];
> -
>      if (!flags) {
>          return "none";
>      }
>
> +    memset(flag_str, 0, sizeof *flag_str);
> +
>      if (flags & FLAG_MULTIPOINT) {
> -        ds_put_cstr(&ds, "multipoint ");
> +        strcat(flag_str, "multipoint ");
>      }
>
>      if (flags & FLAG_DEMAND) {
> -        ds_put_cstr(&ds, "demand ");
> +        strcat(flag_str, "demand ");
>      }
>
>      if (flags & FLAG_AUTH) {
> -        ds_put_cstr(&ds, "auth ");
> +        strcat(flag_str, "auth");
>      }
>
>      if (flags & FLAG_CTL) {
> -        ds_put_cstr(&ds, "ctl ");
> +        strcat(flag_str, "ctl");
>      }
>
>      if (flags & FLAG_FINAL) {
> -        ds_put_cstr(&ds, "final ");
> +        strcat(flag_str, "final");
>      }
>
>      if (flags & FLAG_POLL) {
> -        ds_put_cstr(&ds, "poll ");
> +        strcat(flag_str, "poll");
>      }
>
> -    /* Do not copy the trailing whitespace. */
> -    ds_chomp(&ds, ' ');
> -    ovs_strlcpy(flag_str, ds_cstr(&ds), sizeof flag_str);
> -    ds_destroy(&ds);
>      return flag_str;
>  }
>
> -static const char *
> -bfd_state_str(enum state state)
> +/* Converts the BFD state code to string.
> + * This function is thread-safe and reentrant. */
> +const char *
> +bfd_state_to_str(enum bfd_state state)
>  {
>      switch (state) {
>      case STATE_ADMIN_DOWN: return "admin_down";
> @@ -990,8 +701,10 @@ bfd_state_str(enum state state)
>      }
>  }
>
> -static const char *
> -bfd_diag_str(enum diag diag) {
> +/* Converts the BFD diag to string.
> + * This function is thread-safe and reentrant. */
> +const char *
> +bfd_diag_to_str(enum bfd_diag diag) {
>      switch (diag) {
>      case DIAG_NONE: return "No Diagnostic";
>      case DIAG_EXPIRED: return "Control Detection Time Expired";
> @@ -1004,286 +717,4 @@ bfd_diag_str(enum diag diag) {
>      case DIAG_RCPATH_DOWN: return "Reverse Concatenated Path Down";
>      default: return "Invalid Diagnostic";
>      }
> -};
> -
> -static void
> -log_msg(enum vlog_level level, const struct msg *p, const char *message,
> -        const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    struct ds ds = DS_EMPTY_INITIALIZER;
> -
> -    if (vlog_should_drop(THIS_MODULE, level, &rl)) {
> -        return;
> -    }
> -
> -    ds_put_format(&ds,
> -                  "%s: %s."
> -                  "\n\tvers:%"PRIu8" diag:\"%s\" state:%s mult:%"PRIu8
> -                  " length:%"PRIu8
> -                  "\n\tflags: %s"
> -                  "\n\tmy_disc:0x%"PRIx32" your_disc:0x%"PRIx32
> -                  "\n\tmin_tx:%"PRIu32"us (%"PRIu32"ms)"
> -                  "\n\tmin_rx:%"PRIu32"us (%"PRIu32"ms)"
> -                  "\n\tmin_rx_echo:%"PRIu32"us (%"PRIu32"ms)",
> -                  bfd->name, message, p->vers_diag >> VERS_SHIFT,
> -                  bfd_diag_str(p->vers_diag & DIAG_MASK),
> -                  bfd_state_str(p->flags & STATE_MASK),
> -                  p->mult, p->length, bfd_flag_str(p->flags & FLAGS_MASK),
> -                  ntohl(p->my_disc), ntohl(p->your_disc),
> -                  ntohl(p->min_tx), ntohl(p->min_tx) / 1000,
> -                  ntohl(p->min_rx), ntohl(p->min_rx) / 1000,
> -                  ntohl(p->min_rx_echo), ntohl(p->min_rx_echo) / 1000);
> -    bfd_put_details(&ds, bfd);
> -    VLOG(level, "%s", ds_cstr(&ds));
> -    ds_destroy(&ds);
> -}
> -
> -static void
> -bfd_set_state(struct bfd *bfd, enum state state, enum diag diag)
> -    OVS_REQUIRES(mutex)
> -{
> -    if (bfd->cpath_down) {
> -        diag = DIAG_CPATH_DOWN;
> -    }
> -
> -    if (bfd->state != state || bfd->diag != diag) {
> -        if (!VLOG_DROP_INFO(&rl)) {
> -            struct ds ds = DS_EMPTY_INITIALIZER;
> -
> -            ds_put_format(&ds, "%s: BFD state change: %s->%s"
> -                          " \"%s\"->\"%s\".\n",
> -                          bfd->name, bfd_state_str(bfd->state),
> -                          bfd_state_str(state), bfd_diag_str(bfd->diag),
> -                          bfd_diag_str(diag));
> -            bfd_put_details(&ds, bfd);
> -            VLOG_INFO("%s", ds_cstr(&ds));
> -            ds_destroy(&ds);
> -        }
> -
> -        bfd->state = state;
> -        bfd->diag = diag;
> -
> -        if (bfd->state <= STATE_DOWN) {
> -            bfd->rmt_state = STATE_DOWN;
> -            bfd->rmt_diag = DIAG_NONE;
> -            bfd->rmt_min_rx = 1;
> -            bfd->rmt_flags = 0;
> -            bfd->rmt_disc = 0;
> -            bfd->rmt_min_tx = 0;
> -            /* Resets the min_rx if in_decay. */
> -            if (bfd->in_decay) {
> -                bfd->min_rx = bfd->cfg_min_rx;
> -                bfd->in_decay = false;
> -            }
> -        }
> -        /* Resets the decay when state changes to STATE_UP
> -         * and decay_min_rx is configured. */
> -        if (bfd->state == STATE_UP && bfd->decay_min_rx) {
> -            bfd_decay_update(bfd);
> -        }
> -
> -        seq_change(connectivity_seq_get());
> -    }
> -}
> -
> -static uint64_t
> -bfd_rx_packets(const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    struct netdev_stats stats;
> -
> -    if (!netdev_get_stats(bfd->netdev, &stats)) {
> -        return stats.rx_packets;
> -    } else {
> -        return 0;
> -    }
> -}
> -
> -/* Decays the bfd->min_rx to bfd->decay_min_rx when 'diff' is less than
> - * the 'expect' value. */
> -static void
> -bfd_try_decay(struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    int64_t diff, expect;
> -
> -    /* The 'diff' is the difference between current interface rx_packets
> -     * stats and last-time check.  The 'expect' is the recorded number of
> -     * bfd control packets received within an approximately decay_min_rx
> -     * (2000 ms if decay_min_rx is less than 2000 ms) interval.
> -     *
> -     * Since the update of rx_packets stats at interface happens
> -     * asynchronously to the bfd_rx_packets() function, the 'diff' value
> -     * can be jittered.  Thusly, we double the decay_rx_ctl to provide
> -     * more wiggle room. */
> -    diff = bfd_rx_packets(bfd) - bfd->decay_rx_packets;
> -    expect = 2 * MAX(bfd->decay_rx_ctl, 1);
> -    bfd->in_decay = diff <= expect ? true : false;
> -    bfd_decay_update(bfd);
> -}
> -
> -/* Updates the rx_packets, decay_rx_ctl and decay_detect_time. */
> -static void
> -bfd_decay_update(struct bfd * bfd) OVS_REQUIRES(mutex)
> -{
> -    bfd->decay_rx_packets = bfd_rx_packets(bfd);
> -    bfd->decay_rx_ctl = 0;
> -    bfd->decay_detect_time = MAX(bfd->decay_min_rx, 2000) + time_msec();
> -}
> -
> -static void
> -bfd_forwarding_if_rx_update(struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    int64_t incr = bfd_rx_interval(bfd) * bfd->mult;
> -    bfd->forwarding_if_rx_detect_time = MAX(incr, 2000) + time_msec();
> -}
> -
> -static uint32_t
> -generate_discriminator(void)
> -{
> -    uint32_t disc = 0;
> -
> -    /* RFC 5880 Section 6.8.1
> -     * It SHOULD be set to a random (but still unique) value to improve
> -     * security.  The value is otherwise outside the scope of this
> -     * specification. */
> -
> -    while (!disc) {
> -        struct bfd *bfd;
> -
> -        /* 'disc' is by definition random, so there's no reason to waste
> time
> -         * hashing it. */
> -        disc = random_uint32();
> -        HMAP_FOR_EACH_IN_BUCKET (bfd, node, disc, all_bfds) {
> -            if (bfd->disc == disc) {
> -                disc = 0;
> -                break;
> -            }
> -        }
> -    }
> -
> -    return disc;
> -}
> -
> -static struct bfd *
> -bfd_find_by_name(const char *name) OVS_REQUIRES(mutex)
> -{
> -    struct bfd *bfd;
> -
> -    HMAP_FOR_EACH (bfd, node, all_bfds) {
> -        if (!strcmp(bfd->name, name)) {
> -            return bfd;
> -        }
> -    }
> -    return NULL;
> -}
> -
> -static void
> -bfd_put_details(struct ds *ds, const struct bfd *bfd) OVS_REQUIRES(mutex)
> -{
> -    ds_put_format(ds, "\tForwarding: %s\n",
> -                  bfd_forwarding__(CONST_CAST(struct bfd *, bfd))
> -                  ? "true" : "false");
> -    ds_put_format(ds, "\tDetect Multiplier: %d\n", bfd->mult);
> -    ds_put_format(ds, "\tConcatenated Path Down: %s\n",
> -                  bfd->cpath_down ? "true" : "false");
> -    ds_put_format(ds, "\tTX Interval: Approx %lldms\n",
> bfd_tx_interval(bfd));
> -    ds_put_format(ds, "\tRX Interval: Approx %lldms\n",
> bfd_rx_interval(bfd));
> -    ds_put_format(ds, "\tDetect Time: now %+lldms\n",
> -                  time_msec() - bfd->detect_time);
> -    ds_put_format(ds, "\tNext TX Time: now %+lldms\n",
> -                  time_msec() - bfd->next_tx);
> -    ds_put_format(ds, "\tLast TX Time: now %+lldms\n",
> -                  time_msec() - bfd->last_tx);
> -
> -    ds_put_cstr(ds, "\n");
> -
> -    ds_put_format(ds, "\tLocal Flags: %s\n", bfd_flag_str(bfd->flags));
> -    ds_put_format(ds, "\tLocal Session State: %s\n",
> -                  bfd_state_str(bfd->state));
> -    ds_put_format(ds, "\tLocal Diagnostic: %s\n",
> bfd_diag_str(bfd->diag));
> -    ds_put_format(ds, "\tLocal Discriminator: 0x%"PRIx32"\n", bfd->disc);
> -    ds_put_format(ds, "\tLocal Minimum TX Interval: %lldms\n",
> -                  bfd_min_tx(bfd));
> -    ds_put_format(ds, "\tLocal Minimum RX Interval: %lldms\n",
> bfd->min_rx);
> -
> -    ds_put_cstr(ds, "\n");
> -
> -    ds_put_format(ds, "\tRemote Flags: %s\n",
> bfd_flag_str(bfd->rmt_flags));
> -    ds_put_format(ds, "\tRemote Session State: %s\n",
> -                  bfd_state_str(bfd->rmt_state));
> -    ds_put_format(ds, "\tRemote Diagnostic: %s\n",
> -                  bfd_diag_str(bfd->rmt_diag));
> -    ds_put_format(ds, "\tRemote Discriminator: 0x%"PRIx32"\n",
> bfd->rmt_disc);
> -    ds_put_format(ds, "\tRemote Minimum TX Interval: %lldms\n",
> -                  bfd->rmt_min_tx);
> -    ds_put_format(ds, "\tRemote Minimum RX Interval: %lldms\n",
> -                  bfd->rmt_min_rx);
> -}
> -
> -static void
> -bfd_unixctl_show(struct unixctl_conn *conn, int argc, const char *argv[],
> -                 void *aux OVS_UNUSED) OVS_EXCLUDED(mutex)
> -{
> -    struct ds ds = DS_EMPTY_INITIALIZER;
> -    struct bfd *bfd;
> -
> -    ovs_mutex_lock(&mutex);
> -    if (argc > 1) {
> -        bfd = bfd_find_by_name(argv[1]);
> -        if (!bfd) {
> -            unixctl_command_reply_error(conn, "no such bfd object");
> -            goto out;
> -        }
> -        bfd_put_details(&ds, bfd);
> -    } else {
> -        HMAP_FOR_EACH (bfd, node, all_bfds) {
> -            ds_put_format(&ds, "---- %s ----\n", bfd->name);
> -            bfd_put_details(&ds, bfd);
> -        }
> -    }
> -    unixctl_command_reply(conn, ds_cstr(&ds));
> -    ds_destroy(&ds);
> -
> -out:
> -    ovs_mutex_unlock(&mutex);
> -}
> -
> -
> -static void
> -bfd_unixctl_set_forwarding_override(struct unixctl_conn *conn, int argc,
> -                                    const char *argv[], void *aux
> OVS_UNUSED)
> -    OVS_EXCLUDED(mutex)
> -{
> -    const char *forward_str = argv[argc - 1];
> -    int forwarding_override;
> -    struct bfd *bfd;
> -
> -    ovs_mutex_lock(&mutex);
> -    if (!strcasecmp("true", forward_str)) {
> -        forwarding_override = 1;
> -    } else if (!strcasecmp("false", forward_str)) {
> -        forwarding_override = 0;
> -    } else if (!strcasecmp("normal", forward_str)) {
> -        forwarding_override = -1;
> -    } else {
> -        unixctl_command_reply_error(conn, "unknown fault string");
> -        goto out;
> -    }
> -
> -    if (argc > 2) {
> -        bfd = bfd_find_by_name(argv[1]);
> -        if (!bfd) {
> -            unixctl_command_reply_error(conn, "no such BFD object");
> -            goto out;
> -        }
> -        bfd->forwarding_override = forwarding_override;
> -    } else {
> -        HMAP_FOR_EACH (bfd, node, all_bfds) {
> -            bfd->forwarding_override = forwarding_override;
> -        }
> -    }
> -
> -    unixctl_command_reply(conn, "OK");
> -
> -out:
> -    ovs_mutex_unlock(&mutex);
>  }
> diff --git a/lib/bfd.h b/lib/bfd.h
> index 4e7d4cb..c65a124 100644
> --- a/lib/bfd.h
> +++ b/lib/bfd.h
> @@ -1,4 +1,4 @@
> -/* Copyright (c) 2012 Nicira, Inc.
> +/* Copyright (c) 2014 Nicira, Inc.
>   *
>   * Licensed under the Apache License, Version 2.0 (the "License");
>   * you may not use this file except in compliance with the License.
> @@ -10,46 +10,212 @@
>   * 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.  */
> + * limitations under the License. */
>
>  #ifndef BFD_H
>  #define BFD_H 1
>
> +#include <linux/types.h>
> +#include <stdbool.h>
> +#include <stddef.h>
> +#include <stdint.h>
> +
> +#define BFD_VERSION 1
>  #define BFD_PACKET_LEN 24
>  #define BFD_DEST_PORT 3784
>
> -#include <stdbool.h>
> -#include <inttypes.h>
> -
> -struct bfd;
> -struct dpif_flow_stats;
> -struct flow;
> -struct flow_wildcards;
> -struct netdev;
> -struct ofpbuf;
> -struct smap;
> -
> -void bfd_wait(const struct bfd *);
> -void bfd_run(struct bfd *);
> -
> -bool bfd_should_send_packet(const struct bfd *);
> -void bfd_put_packet(struct bfd *bfd, struct ofpbuf *packet,
> -                    uint8_t eth_src[6]);
> -
> -bool bfd_should_process_flow(const struct bfd *, const struct flow *,
> -                             struct flow_wildcards *);
> -void bfd_process_packet(struct bfd *, const struct flow *,
> -                        const struct ofpbuf *);
> -
> -struct bfd *bfd_configure(struct bfd *, const char *name,
> -                          const struct smap *smap,
> -                          struct netdev *netdev);
> -struct bfd *bfd_ref(const struct bfd *);
> -void bfd_unref(struct bfd *);
> -
> -void bfd_account_rx(struct bfd *, const struct dpif_flow_stats *);
> -bool bfd_forwarding(struct bfd *);
> -void bfd_get_status(const struct bfd *, struct smap *);
> -void bfd_set_netdev(struct bfd *, const struct netdev *);
> -long long int bfd_wake_time(const struct bfd *);
> +#define VERS_SHIFT 5
> +#define DIAG_MASK 0x1f
> +#define STATE_MASK 0xC0
> +#define FLAGS_MASK 0x3f
> +
> +/* RFC 5880 Section 4.1
> + *  0                   1                   2                   3
> + *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * |Vers |  Diag   |Sta|P|F|C|A|D|M|  Detect Mult  |    Length     |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * |                       My Discriminator                        |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * |                      Your Discriminator                       |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * |                    Desired Min TX Interval                    |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * |                   Required Min RX Interval                    |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
> + * |                 Required Min Echo RX Interval                 |
> + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
> +struct bfd_msg {
> +    uint8_t vers_diag;    /* Version and diagnostic. */
> +    uint8_t flags;        /* 2bit State field followed by flags. */
> +    uint8_t mult;         /* Fault detection multiplier. */
> +    uint8_t length;       /* Length of this BFD message. */
> +    __be32 my_disc;       /* My discriminator. */
> +    __be32 your_disc;     /* Your discriminator. */
> +    __be32 min_tx;        /* Desired minimum tx interval. */
> +    __be32 min_rx;        /* Required minimum rx interval. */
> +    __be32 min_rx_echo;   /* Required minimum echo rx interval. */
> +};
> +
> +enum bfd_flags {
> +    FLAG_MULTIPOINT = 1 << 0,
> +    FLAG_DEMAND = 1 << 1,
> +    FLAG_AUTH = 1 << 2,
> +    FLAG_CTL = 1 << 3,
> +    FLAG_FINAL = 1 << 4,
> +    FLAG_POLL = 1 << 5
> +};
> +
> +enum bfd_state {
> +    STATE_ADMIN_DOWN = 0 << 6,
> +    STATE_DOWN = 1 << 6,
> +    STATE_INIT = 2 << 6,
> +    STATE_UP = 3 << 6
> +};
> +
> +enum bfd_diag {
> +    DIAG_NONE = 0,                /* No Diagnostic. */
> +    DIAG_EXPIRED = 1,             /* Control Detection Time Expired. */
> +    DIAG_ECHO_FAILED = 2,         /* Echo Function Failed. */
> +    DIAG_RMT_DOWN = 3,            /* Neighbor Signaled Session Down. */
> +    DIAG_FWD_RESET = 4,           /* Forwarding Plane Reset. */
> +    DIAG_PATH_DOWN = 5,           /* Path Down. */
> +    DIAG_CPATH_DOWN = 6,          /* Concatenated Path Down. */
> +    DIAG_ADMIN_DOWN = 7,          /* Administratively Down. */
> +    DIAG_RCPATH_DOWN = 8          /* Reverse Concatenated Path Down. */
> +};
> +
> +enum bfd_error {
> +    BFD_PASS = 0,                 /* No error. */
> +    BFD_EINVAL = 1,               /* Invalid arguments. */
> +    BFD_EPOLL = 2,                /* bfd poll and final flags are both
> on. */
> +    BFD_EMSG = 3                  /* bfd control packet error. */
> +};
> +
> +/* Used to configure a BFD session. */
> +struct bfd_setting {
> +    char *name;                   /* Name of the monitored interface. */
> +
> +    /* Local state variables. */
> +    uint32_t disc;                /* bfd.LocalDiscr. */
> +    uint8_t mult;                 /* bfd.DetectMult. */
> +    uint32_t min_tx;              /* bfd.DesiredMinTxInterval. */
> +    uint32_t min_rx;              /* bfd.RequiredMinRxInterval. */
> +
> +    /* Open Vswitch specific settings. */
> +    bool cpath_down;              /* Set Concatenated Path Down. */
> +    bool forwarding_override;     /* Manual override of 'forwarding'
> status. */
> +    int forward_if_rx_interval;   /* How often to detect forward_if_rx. */
> +    int decay_min_rx;             /* bfd.min_rx is set to decay_min_rx
> when */
> +                                  /* in decay. */
> +};
> +
> +/* BFD status. */
> +struct bfd_status {
> +    char *name;                   /* Name of the monitored interface. */
> +    bool forwarding;              /* The liveness of bfd session. */
> +    uint8_t mult;                 /* bfd.DetectMult. */
> +    bool cpath_down;              /* If cpath_down enabled. */
> +    uint32_t tx_interval;         /* tx interval in use. */
> +    uint32_t rx_interval;         /* rx interval in use. */
> +
> +    uint32_t local_disc;          /* bfd.LocalDiscr. */
> +    uint32_t local_min_tx;        /* bfd.DesiredMinTxInterval */
> +    uint32_t local_min_rx;        /* bfd.DesiredMinRxInterval*/
> +    enum bfd_flags local_flags;   /* Flags sent on messages. */
> +    enum bfd_state local_state;   /* bfd.SessionState. */
> +    enum bfd_diag local_diag;     /* bfd.LocalDiag. */
> +    long long int detect_time;    /* RFC 5880 6.8.4 Detection time. */
> +    long long int last_tx;        /* Last TX time. */
> +    long long int next_tx;        /* Next TX time. */
> +
> +    uint32_t rmt_disc;            /* bfd.RemoteDiscr. */
> +    uint32_t rmt_min_tx;          /* bfd.RemoteMinTxInterval */
> +    uint32_t rmt_min_rx;          /* bfd.RemoteMinRxInterval*/
> +    enum bfd_flags rmt_flags;     /* Flags last received. */
> +    enum bfd_state rmt_state;     /* bfd.RemoteSessionState. */
> +    enum bfd_diag rmt_diag;       /* Remote diagnostic. */
> +
> +    uint64_t flap_count;          /* Flap count of forwarding. */
> +};
> +
> +/* A BFD session.  Users are not permitted to directly access the variable
> + * of this struct.  For BFD configuration, use the bfd_configure().  For
> + * BFD status extraction, use the bfd_get_status().
> + *
> + * User must guarantee the 'name''s memory is retained throughout the
> + * lifetime of the struct.
> + * */
> +struct bfd {
> +    char *name;                   /* Name of the monitored interface. */
> +
> +    /* Local state variables. */
> +    uint32_t disc;                /* bfd.LocalDiscr. */
> +    uint8_t mult;                 /* bfd.DetectMult. */
> +    enum bfd_state state;         /* bfd.SessionState. */
> +    enum bfd_diag diag;           /* bfd.LocalDiag. */
> +    enum bfd_flags flags;         /* Flags sent on messages. */
> +    uint32_t min_tx;              /* bfd.DesiredMinTxInterval. */
> +    uint32_t min_rx;              /* bfd.RequiredMinRxInterval. */
> +    uint32_t cfg_min_tx;          /* Configured minimum TX rate. */
> +    uint32_t cfg_min_rx;          /* Configured required minimum RX rate.
> */
> +    long long int detect_time;    /* RFC 5880 6.8.4 Detection time. */
> +    long long int last_tx;        /* Last TX time. */
> +    long long int next_tx;        /* Next TX time. */
> +
> +    /* Remote side state variables. */
> +    uint32_t rmt_disc;            /* bfd.RemoteDiscr. */
> +    enum bfd_state rmt_state;     /* bfd.RemoteSessionState. */
> +    enum bfd_diag rmt_diag;       /* Remote diagnostic. */
> +    enum bfd_flags rmt_flags;     /* Flags last received. */
> +    long long int rmt_min_rx;     /* bfd.RemoteMinRxInterval. */
> +    long long int rmt_min_tx;     /* Remote minimum TX interval. */
> +
> +    /* POLL sequence. */
> +    uint32_t poll_min_tx;         /* min_tx in POLL sequence. */
> +    uint32_t poll_min_rx;         /* min_rx in POLL sequence. */
> +
> +    /* Open Vswitch specific features. */
> +    bool cpath_down;              /* Set Concatenated Path Down. */
> +
> +    int forwarding_override;      /* Manual override of 'forwarding'
> status. */
> +
> +    /* Equivalent to bfd demand mode. */
> +    bool last_forwarding;         /* Last calculation of forwarding flag.
> */
> +    int forward_if_rx_interval;   /* How often to detect forward_if_rx. */
> +    long long int forward_if_rx_detect_time;
> +    bool forward_if_rx_data;      /* Data packet received in last
> interval. */
> +
> +    /* BFD decay feature is for reducing the */
> +    bool in_decay;                /* True when bfd is in decay. */
> +    int decay_min_rx;             /* bfd.min_rx is set to decay_min_rx
> when */
> +                                  /* in decay. */
> +    long long int decay_detect_time; /* Next decay detect time. */
> +    uint32_t decay_rx_count;      /* Count of data packets received. */
> +
> +    uint64_t flap_count;          /* Counts bfd forwarding flaps. */
> +};
> +
> +enum bfd_error bfd_configure(struct bfd *, const struct bfd_setting *);
> +long long int bfd_wait(const struct bfd *);
> +
> +void bfd_run(struct bfd *, long long int now);
> +void bfd_get_status(const struct bfd *, struct bfd_status *);
> +bool bfd_forwarding(const struct bfd *, long long int now);
> +void bfd_account_rx(struct bfd *, uint32_t n_pkt);
> +
> +bool bfd_should_send_packet(const struct bfd *, long long int now);
> +enum bfd_error bfd_put_packet(struct bfd *, void *, size_t len,
> +                              long long int now);
> +bool bfd_should_process_packet(const __be16 eth_type, const uint8_t
> ip_proto,
> +                               const __be16 udp_dst);
> +enum bfd_error bfd_process_packet(struct bfd *, void *, size_t len,
> +                                  long long now);
> +
> +/* Helpers. */
> +const char * bfd_error_to_str(enum bfd_error error);
> +const char * bfd_flag_to_str(enum bfd_flags flags);
> +const char * bfd_state_to_str(enum bfd_state state);
> +const char * bfd_diag_to_str(enum bfd_diag diag);
> +
>  #endif /* bfd.h */
> diff --git a/lib/bfd_ts.c b/lib/bfd_ts.c
> new file mode 100644
> index 0000000..1d71d70
> --- /dev/null
> +++ b/lib/bfd_ts.c
> @@ -0,0 +1,621 @@
> +/* Copyright (c) 2014 Nicira, Inc.
> + *
> + * 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 "bfd.h"
> +#include "bfd_ts.h"
> +
> +#include <sys/types.h>
> +#include <arpa/inet.h>
> +#include <netinet/in_systm.h>
> +#include <netinet/ip.h>
> +#include <errno.h>
> +
> +#include "byte-order.h"
> +#include "connectivity.h"
> +#include "csum.h"
> +#include "dpif.h"
> +#include "dynamic-string.h"
> +#include "flow.h"
> +#include "hmap.h"
> +#include "odp-util.h"
> +#include "ofpbuf.h"
> +#include "ovs-thread.h"
> +#include "openvswitch/types.h"
> +#include "packets.h"
> +#include "poll-loop.h"
> +#include "random.h"
> +#include "seq.h"
> +#include "smap.h"
> +#include "timeval.h"
> +#include "unaligned.h"
> +#include "unixctl.h"
> +#include "util.h"
> +#include "vlog.h"
> +
> +VLOG_DEFINE_THIS_MODULE(bfd_ts);
> +
> +static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(20, 20);
> +
> +static struct ovs_mutex mutex = OVS_MUTEX_INITIALIZER;
> +static struct hmap all_bfds__ = HMAP_INITIALIZER(&all_bfds__);
> +static struct hmap *const all_bfds OVS_GUARDED_BY(mutex) = &all_bfds__;
> +
> +/* Thread-safe wrapper for bfd.{c,h}.
> + * The 'struct bfd_ts' is the thread-safe wrapper for 'struct bfd'.  It
> + * contains the additional information (e.g. monitored interface name)
> + * and header fields needed for construction and parse of the BFD control
> + * packet.  Each 'struct bfd' should be created by creating the
> + * 'struct bfd_ts'.  Thusly, the argument 'struct bfd *' can be converted
> to
> + * the corresponding 'struct bfd_ts *'. */
> +struct bfd_ts {
> +    struct hmap_node node;        /* In 'all_bfds'. */
> +    struct bfd bfd;               /* The BFD session. */
> +    char *name;                   /* Name of the monitored interface. */
> +    uint32_t disc;                /* bfd.Discriminator. */
> +    uint64_t last_flap_count;     /* Last check of bfd.flap_count value.
> */
> +    atomic_int ref_cnt;           /* Reference counter. */
> +
> +    bool check_tnl_key;           /* Verify tunnel key of inbound
> packets? */
> +    uint8_t eth_dst[ETH_ADDR_LEN];/* Ethernet destination address. */
> +    bool eth_dst_set;             /* 'eth_dst' set through database. */
> +    ovs_be32 ip_src;              /* IPv4 source address. */
> +    ovs_be32 ip_dst;              /* IPv4 destination address. */
> +    uint32_t udp_src;             /* UDP source port. */
> +};
> +
> +
> +static void
> +bfd_ts_check_flap(struct bfd *bfd)  OVS_REQUIRES(mutex)
> +{
> +    struct bfd_ts *ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +    struct bfd_status s;
> +
> +    bfd_get_status(bfd, &s);
> +
> +    if (ts->last_flap_count != s.flap_count) {
> +        seq_change(connectivity_seq_get());
> +        ts->last_flap_count = s.flap_count;
> +    }
> +}
> +
> +static uint32_t
> +bfd_ts_generate_discriminator(void) OVS_REQUIRES(mutex)
> +{
> +    uint32_t disc = 0;
> +
> +    /* RFC 5880 Section 6.8.1
> +     * It SHOULD be set to a random (but still unique) value to improve
> +     * security.  The value is otherwise outside the scope of this
> +     * specification. */
> +    while (!disc) {
> +        struct bfd_ts *ts;
> +
> +        /* 'disc' is by definition random, so there's no reason to waste
> time
> +         * hashing it. */
> +        disc = random_uint32();
> +        HMAP_FOR_EACH_IN_BUCKET (ts, node, disc, all_bfds) {
> +            if (ts->disc == disc) {
> +                disc = 0;
> +                break;
> +            }
> +        }
> +    }
> +
> +    return disc;
> +}
> +
> +static bool
> +bfd_ts_lookup_ip(const char *host_name, struct in_addr *addr)
> +    OVS_REQUIRES(mutex)
> +{
> +    if (!inet_pton(AF_INET, host_name, addr)) {
> +        VLOG_WARN("\"%s\" is not a valid IP address", host_name);
> +
> +        return false;
> +    }
> +
> +    return true;
> +}
> +
> +static struct bfd *
> +bfd_ts_find_by_name(const char *name)
> +    OVS_REQUIRES(mutex)
> +{
> +    struct bfd_ts *ts;
> +
> +    HMAP_FOR_EACH (ts, node, all_bfds) {
> +        if (!strcmp(ts->name, name)) {
> +            return &ts->bfd;
> +        }
> +    }
> +
> +    return NULL;
> +}
> +
> +static void
> +bfd_ts_put_details(struct ds *ds, const struct bfd *bfd)
> +    OVS_REQUIRES(mutex)
> +{
> +    struct bfd_status status;
> +    bfd_get_status(bfd, &status);
> +
> +    ds_put_format(ds, "\tForwarding: %s\n",
> +                  bfd_forwarding(bfd, time_msec()) ? "true" : "false");
> +    ds_put_format(ds, "\tDetect Multiplier: %d\n", status.mult);
> +    ds_put_format(ds, "\tConcatenated Path Down: %s\n",
> +                  status.cpath_down ? "true" : "false");
> +    ds_put_format(ds, "\tTX Interval: Approx %ums\n", status.tx_interval);
> +    ds_put_format(ds, "\tRX Interval: Approx %ums\n", status.rx_interval);
> +    ds_put_format(ds, "\tDetect Time: now %+lldms\n",
> +                  time_msec() - status.detect_time);
> +    ds_put_format(ds, "\tNext TX Time: now %+lldms\n",
> +                  time_msec() - status.next_tx);
> +    ds_put_format(ds, "\tLast TX Time: now %+lldms\n",
> +                  time_msec() - status.last_tx);
> +
> +    ds_put_cstr(ds, "\n");
> +
> +    ds_put_format(ds, "\tLocal Flags: %s\n",
> +                  bfd_flag_to_str(status.local_flags));
> +    ds_put_format(ds, "\tLocal Session State: %s\n",
> +                  bfd_state_to_str(status.local_state));
> +    ds_put_format(ds, "\tLocal Diagnostic: %s\n",
> +                  bfd_diag_to_str(status.local_diag));
> +    ds_put_format(ds, "\tLocal Discriminator: 0x%"PRIx32"\n",
> +                  status.local_disc);
> +    ds_put_format(ds, "\tLocal Minimum TX Interval: %dms\n",
> +                  status.local_min_tx);
> +    ds_put_format(ds, "\tLocal Minimum RX Interval: %ums\n",
> +                  status.local_min_rx);
> +
> +    ds_put_cstr(ds, "\n");
> +
> +    ds_put_format(ds, "\tRemote Flags: %s\n",
> +                  bfd_flag_to_str(status.rmt_flags));
> +    ds_put_format(ds, "\tRemote Session State: %s\n",
> +                  bfd_state_to_str(status.rmt_state));
> +    ds_put_format(ds, "\tRemote Diagnostic: %s\n",
> +                  bfd_diag_to_str(status.rmt_diag));
> +    ds_put_format(ds, "\tRemote Discriminator: 0x%"PRIx32"\n",
> +                  status.rmt_disc);
> +    ds_put_format(ds, "\tRemote Minimum TX Interval: %ums\n",
> +                  status.rmt_min_tx);
> +    ds_put_format(ds, "\tRemote Minimum RX Interval: %ums\n",
> +                  status.rmt_min_rx);
> +}
> +
> +static void
> +bfd_ts_unixctl_show(struct unixctl_conn *conn, int argc, const char
> *argv[],
> +                    void *aux OVS_UNUSED)
> +    OVS_EXCLUDED(mutex)
> +{
> +    struct ds ds = DS_EMPTY_INITIALIZER;
> +
> +    ovs_mutex_lock(&mutex);
> +    if (argc > 1) {
> +        struct bfd *bfd;
> +
> +        bfd = bfd_ts_find_by_name(argv[1]);
> +        if (!bfd) {
> +            unixctl_command_reply_error(conn, "no such bfd object");
> +            goto out;
> +        }
> +        bfd_ts_put_details(&ds, bfd);
> +    } else {
> +        struct bfd_ts *ts;
> +
> +        HMAP_FOR_EACH (ts, node, all_bfds) {
> +            ds_put_format(&ds, "---- %s ----\n", ts->name);
> +            bfd_ts_put_details(&ds, &ts->bfd);
> +        }
> +    }
> +    unixctl_command_reply(conn, ds_cstr(&ds));
> +    ds_destroy(&ds);
> +
> +out:
> +    ovs_mutex_unlock(&mutex);
> +}
> +
> +static void
> +bfd_ts_unixctl_set_forwarding_override(struct unixctl_conn *conn, int
> argc,
> +                                       const char *argv[], void *aux
> OVS_UNUSED)
> +    OVS_EXCLUDED(mutex)
> +{
> +    const char *forward_str = argv[argc - 1];
> +    int forwarding_override;
> +
> +    ovs_mutex_lock(&mutex);
> +    if (!strcasecmp("true", forward_str)) {
> +        forwarding_override = 1;
> +    } else if (!strcasecmp("false", forward_str)) {
> +        forwarding_override = -1;
> +    } else if (!strcasecmp("normal", forward_str)) {
> +        forwarding_override = 0;
> +    } else {
> +        unixctl_command_reply_error(conn, "unknown fault string");
> +        goto out;
> +    }
> +
> +    if (argc > 2) {
> +        struct bfd *bfd;
> +
> +        bfd = bfd_ts_find_by_name(argv[1]);
> +        if (!bfd) {
> +            unixctl_command_reply_error(conn, "no such BFD object");
> +            goto out;
> +        }
> +        bfd->forwarding_override = forwarding_override;
> +    } else {
> +        struct bfd_ts *ts;
> +
> +        HMAP_FOR_EACH (ts, node, all_bfds) {
> +            ts->bfd.forwarding_override = forwarding_override;
> +        }
> +    }
> +
> +    unixctl_command_reply(conn, "OK");
> +
> +out:
> +    ovs_mutex_unlock(&mutex);
> +}
> +
> +
> +/* Initializes, destroys, or reconfigures the BFD session 'bfd' and the
> wrapper
> + * 'struct bfd_ts' (named 'name'), according to the database configuration
> + * contained in 'cfg'.  Takes ownership of 'bfd', which may be NULL.
>  Returns
> + * a BFD object which may be used as a handle for the session, or NULL if
> BFD
> + * is not enabled according to 'cfg'.  Also returns NULL if cfg is NULL.
> */
> +struct bfd *
> +bfd_ts_configure(struct bfd *bfd, const char *name, const struct smap
> *cfg)
> +{
> +    static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
> +    static atomic_uint16_t udp_src = ATOMIC_VAR_INIT(0);
> +    struct bfd_ts *ts;
> +    struct bfd_setting setting;
> +    const char *hwaddr, *ip_src, *ip_dst;
> +    struct in_addr in_addr;
> +    uint8_t ea[ETH_ADDR_LEN];
> +
> +    if (ovsthread_once_start(&once)) {
> +        unixctl_command_register("bfd/show", "[interface]", 0, 1,
> +                                 bfd_ts_unixctl_show, NULL);
> +        unixctl_command_register("bfd/set-forwarding",
> +                                 "[interface] normal|false|true", 1, 2,
> +                                 bfd_ts_unixctl_set_forwarding_override,
> NULL);
> +        ovsthread_once_done(&once);
> +    }
> +
> +    if (!cfg || !smap_get_bool(cfg, "enable", false)) {
> +        bfd_ts_unref(bfd);
> +        return NULL;
> +    }
> +
> +    ovs_mutex_lock(&mutex);
> +    if (!bfd) {
> +        ts = xzalloc(sizeof *ts);
> +
> +        ts->name = xstrdup(name);
> +        ts->disc = bfd_ts_generate_discriminator();
> +        atomic_init(&ts->ref_cnt, 1);
> +
> +        /* RFC 5881 section 4
> +         * The source port MUST be in the range 49152 through 65535.  The
> same
> +         * UDP source port number MUST be used for all BFD Control packets
> +         * associated with a particular session.  The source port number
> SHOULD
> +         * be unique among all BFD sessions on the system. */
> +        atomic_add(&udp_src, 1, &ts->udp_src);
> +        ts->udp_src = (ts->udp_src % 16384) + 49152;
> +
> +        hmap_insert(all_bfds, &ts->node, ts->disc);
> +    } else {
> +        ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +    }
> +
> +    /* Congfiures the 'struct bfd_ts'. */
> +    ts->check_tnl_key = smap_get_bool(cfg, "check_tnl_key", false);
> +
> +    hwaddr = smap_get(cfg, "bfd_dst_mac");
> +    if (hwaddr && eth_addr_from_string(hwaddr, ea) &&
> !eth_addr_is_zero(ea)) {
> +        memcpy(ts->eth_dst, ea, ETH_ADDR_LEN);
> +        ts->eth_dst_set = true;
> +    } else if (ts->eth_dst_set) {
> +        memcpy(ts->eth_dst, eth_addr_bfd, ETH_ADDR_LEN);
> +        ts->eth_dst_set = false;
> +    }
> +
> +    ip_src = smap_get(cfg, "bfd_src_ip");
> +    if (ip_src && bfd_ts_lookup_ip(ip_src, &in_addr)) {
> +        memcpy(&ts->ip_src, &in_addr, sizeof in_addr);
> +    } else {
> +        ts->ip_src = htonl(0xA9FE0100); /* 169.254.1.0. */
> +    }
> +
> +    ip_dst = smap_get(cfg, "bfd_dst_ip");
> +    if (ip_dst && bfd_ts_lookup_ip(ip_dst, &in_addr)) {
> +        memcpy(&ts->ip_dst, &in_addr, sizeof in_addr);
> +    } else {
> +        ts->ip_dst = htonl(0xA9FE0101); /* 169.254.1.1. */
> +    }
> +
> +    /* Configures the 'struct bfd'. */
> +    setting.name = ts->name;
> +    setting.disc = ts->disc;
> +    setting.mult = 3;
> +    setting.min_tx = smap_get_int(cfg, "min_tx", 100);
> +    setting.min_rx = smap_get_int(cfg, "min_rx", 1000);
> +    setting.cpath_down = smap_get_bool(cfg, "cpath_down", false);
> +    setting.forward_if_rx_interval = smap_get_bool(cfg,
> "forwarding_if_rx",
> +                                                   0) ? 3000 : 0;
> +    setting.decay_min_rx = smap_get_int(cfg, "decay_min_rx", 0);
> +
> +    /* Since forwarding_override can only be set via 'ovs-appctl'
> +     * command, use this hack to retain its configured value. */
> +    setting.forwarding_override = ts->bfd.forwarding_override;
> +    bfd_configure(&ts->bfd, &setting);
> +
> +    ovs_mutex_unlock(&mutex);
> +
> +    return &ts->bfd;
> +}
> +
> +/* Called when accounting the number of packets received from the
> interface. */
> +void
> +bfd_ts_account_rx(struct bfd *bfd, uint32_t n_pkt)
> +{
> +    ovs_mutex_lock(&mutex);
> +    bfd_account_rx(bfd, n_pkt);
> +    ovs_mutex_unlock(&mutex);
> +}
> +
> +/* References the 'bfd' in the corresponding 'strcut bfd_ts'. */
> +struct bfd *
> +bfd_ts_ref(const struct bfd *bfd_)
> +{
> +    struct bfd *bfd = CONST_CAST(struct bfd *, bfd_);
> +    struct bfd_ts *ts;
> +
> +    if (bfd) {
> +        int orig;
> +
> +        ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +        atomic_add(&ts->ref_cnt, 1, &orig);
> +        ovs_assert(orig > 0);
> +    }
> +    return bfd;
> +}
> +
> +/* Un-references the 'bfd' in the corresponding 'strcut bfd_ts'.  Frees
> + * the memory if the new 'ref_count' is 0. */
> +void
> +bfd_ts_unref(struct bfd *bfd)
> +{
> +    if (bfd) {
> +        int orig;
> +        struct bfd_ts *ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +
> +        atomic_sub(&ts->ref_cnt, 1, &orig);
> +        ovs_assert(orig > 0);
> +        if (orig == 1) {
> +            ovs_mutex_lock(&mutex);
> +            hmap_remove(all_bfds, &ts->node);
> +            free(ts->name);
> +            free(ts);
> +            ovs_mutex_unlock(&mutex);
> +        }
> +    }
> +}
> +
> +/* Returns a 'smap' of key value pairs representing the status of 'bfd'
> + * intended for the OVS database. */
> +int
> +bfd_ts_get_status(struct bfd *bfd, struct smap *smap)
> +{
> +    struct bfd_status status;
> +
> +    ovs_mutex_lock(&mutex);
> +    if (!bfd) {
> +        ovs_mutex_unlock(&mutex);
> +        return ENOENT;
> +    }
> +
> +    bfd_get_status(bfd, &status);
> +
> +    smap_add(smap, "forwarding", bfd_forwarding(bfd, time_msec())
> +             ? "true" : "false");
> +    smap_add(smap, "state", bfd_state_to_str(status.local_state));
> +    smap_add(smap, "diagnostic", bfd_diag_to_str(status.local_diag));
> +    smap_add_format(smap, "flap_count", "%"PRIu64, status.flap_count);
> +
> +    if (status.local_state != STATE_DOWN) {
> +        smap_add(smap, "remote_state",
> bfd_state_to_str(status.rmt_state));
> +        smap_add(smap, "remote_diagnostic",
> bfd_diag_to_str(status.rmt_diag));
> +    }
> +
> +    ovs_mutex_unlock(&mutex);
> +    return 0;
> +}
> +
> +/* Queries the bfd.forwarding flag. */
> +bool
> +bfd_ts_forwarding(struct bfd *bfd)
> +{
> +    bool ret;
> +
> +    ovs_mutex_lock(&mutex);
> +    ret = bfd_forwarding(bfd, time_msec());
> +    ovs_mutex_unlock(&mutex);
> +
> +    return ret;
> +}
> +
> +/* Called to check the BFD sessions status, decay and forwarding_if_rx. */
> +void
> +bfd_ts_run(struct bfd *bfd)
> +{
> +    ovs_mutex_lock(&mutex);
> +    bfd_run(bfd, time_msec());
> +    bfd_ts_check_flap(bfd);
> +    ovs_mutex_unlock(&mutex);
> +}
> +
> +/* Registers the next wakeup time with the poll loop. */
> +void
> +bfd_ts_wait(const struct bfd *bfd)
> +{
> +    poll_timer_wait_until(bfd_ts_wake_time(bfd));
> +}
> +
> +/* Returns the next wakeup time of the BFD session. */
> +long long int
> +bfd_ts_wake_time(const struct bfd *bfd)
> +{
> +    long long int ret;
> +
> +    ovs_mutex_lock(&mutex);
> +    ret = bfd_wait(bfd);
> +    ovs_mutex_unlock(&mutex);
> +
> +    return ret;
> +}
> +
> +/* Checks if the BFD control packet should be sent. */
> +bool
> +bfd_ts_should_send_packet(struct bfd *bfd)
> +{
> +    bool ret;
> +
> +    ovs_mutex_lock(&mutex);
> +    ret = bfd_should_send_packet(bfd, time_msec());
> +    ovs_mutex_unlock(&mutex);
> +
> +    return ret;
> +}
> +
> +/* Constructs the entire BFD control packet. */
> +void
> +bfd_ts_put_packet(struct bfd *bfd, struct ofpbuf *p,
> +                  uint8_t eth_src[ETH_ADDR_LEN])
> +{
> +    struct udp_header *udp;
> +    struct eth_header *eth;
> +    struct ip_header *ip;
> +    struct bfd_msg *msg;
> +    struct bfd_ts *ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +    struct bfd_status s;
> +
> +    ovs_mutex_lock(&mutex);
> +    bfd_get_status(bfd, &s);
> +    if (s.next_tx) {
> +        long long int delay = time_msec() - s.next_tx;
> +        if (delay > s.tx_interval * 3 / 2) {
> +            VLOG_INFO("%s: long delay of %lldms (expected %ums) sending
> BFD"
> +                      " control message", ts->name, delay, s.tx_interval);
> +        }
> +    }
> +
> +    /* RFC 5880 Section 6.5
> +     * A BFD Control packet MUST NOT have both the Poll (P) and Final (F)
> bits
> +     * set. */
> +    ovs_assert(!(s.local_flags & FLAG_POLL) || !(s.local_flags &
> FLAG_FINAL));
> +
> +    ofpbuf_reserve(p, 2); /* Properly align after the ethernet header. */
> +    eth = ofpbuf_put_uninit(p, sizeof *eth);
> +    memcpy(eth->eth_src, eth_src, ETH_ADDR_LEN);
> +    memcpy(eth->eth_dst, ts->eth_dst, ETH_ADDR_LEN);
> +    eth->eth_type = htons(ETH_TYPE_IP);
> +
> +    ip = ofpbuf_put_zeros(p, sizeof *ip);
> +    ip->ip_ihl_ver = IP_IHL_VER(5, 4);
> +    ip->ip_tot_len = htons(sizeof *ip + sizeof *udp + sizeof *msg);
> +    ip->ip_ttl = MAXTTL;
> +    ip->ip_tos = IPTOS_LOWDELAY | IPTOS_THROUGHPUT;
> +    ip->ip_proto = IPPROTO_UDP;
> +    put_16aligned_be32(&ip->ip_src, ts->ip_src);
> +    put_16aligned_be32(&ip->ip_dst, ts->ip_dst);
> +    ip->ip_csum = csum(ip, sizeof *ip);
> +
> +    udp = ofpbuf_put_zeros(p, sizeof *udp);
> +    udp->udp_src = htons(ts->udp_src);
> +    udp->udp_dst = htons(BFD_DEST_PORT);
> +    udp->udp_len = htons(sizeof *udp + sizeof *msg);
> +
> +    bfd_put_packet(bfd, ofpbuf_put_uninit(p, sizeof *msg),
> +                   BFD_PACKET_LEN, time_msec());
> +    ovs_mutex_unlock(&mutex);
> +}
> +
> +/* Checks if the received packet should be processed as BFD control
> + * packet. */
> +bool
> +bfd_ts_should_process_packet(struct bfd *bfd, const struct flow *flow,
> +                             struct flow_wildcards *wc)
> +{
> +    struct bfd_ts *ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +    bool ret = false;
> +
> +    ovs_mutex_lock(&mutex);
> +    memset(&wc->masks.dl_dst, 0xff, sizeof wc->masks.dl_dst);
> +    if (ts->eth_dst_set && memcmp(ts->eth_dst, flow->dl_dst,
> ETH_ADDR_LEN)) {
> +        goto out;
> +    }
> +
> +    memset(&wc->masks.nw_proto, 0xff, sizeof wc->masks.nw_proto);
> +    memset(&wc->masks.tp_dst, 0xff, sizeof wc->masks.tp_dst);
> +
> +    if (ts->check_tnl_key) {
> +        memset(&wc->masks.tunnel.tun_id, 0xff, sizeof
> wc->masks.tunnel.tun_id);
> +    }
> +
> +    ret = (!ts->check_tnl_key || flow->tunnel.tun_id == htonll(0))
> +          && bfd_should_process_packet(flow->dl_type, flow->nw_proto,
> +                                       flow->tp_dst);
> +out:
> +    ovs_mutex_unlock(&mutex);
> +
> +    return ret;
> +}
> +
> +
> +/* Processes the BFD control packet.  Updates the corresponding BFD
> status. */
> +int
> +bfd_ts_process_packet(struct bfd *bfd, const struct flow *flow,
> +                      const struct ofpbuf *p)
> +{
> +    struct bfd_ts *ts = CONTAINER_OF(bfd, struct bfd_ts, bfd);
> +    void *msg;
> +
> +    ovs_mutex_lock(&mutex);
> +    if (flow->nw_ttl != 255) {
> +        /* XXX Should drop in the kernel to prevent DOS. */
> +        goto out;
> +    }
> +
> +    msg = ofpbuf_at(p, (uint8_t *)p->l7 - (uint8_t *)p->data,
> BFD_PACKET_LEN);
> +    if (!msg) {
> +        VLOG_INFO_RL(&rl, "%s: Received too-short BFD control message
> (only "
> +                     "%"PRIdPTR" bytes long, at least %d required).",
> +                     ts->name, (uint8_t *) ofpbuf_tail(p) - (uint8_t *)
> p->l7,
> +                     BFD_PACKET_LEN);
> +        goto out;
> +    }
> +    bfd_process_packet(bfd, msg, BFD_PACKET_LEN, time_msec());
> +
> +    bfd_ts_check_flap(bfd);
> +out:
> +    ovs_mutex_unlock(&mutex);
> +
> +    return 0;
> +}
> diff --git a/lib/bfd_ts.h b/lib/bfd_ts.h
> new file mode 100644
> index 0000000..86f62e4
> --- /dev/null
> +++ b/lib/bfd_ts.h
> @@ -0,0 +1,48 @@
> +/* Copyright (c) 2014 Nicira, Inc.
> + *
> + * 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. */
> +
> +#ifndef BFD_TS_H
> +#define BFD_TS_H 1
> +
> +#include <stdbool.h>
> +#include <inttypes.h>
> +
> +#include "packets.h"
> +
> +/* A thread-safe wrapper for bfd.{c,h}. */
> +struct bfd;
> +struct flow;
> +struct ofpbuf;
> +struct smap;
> +
> +struct bfd * bfd_ts_configure(struct bfd *, const char *,
> +                              const struct smap *);
> +void bfd_ts_account_rx(struct bfd *, uint32_t n_pkt);
> +struct bfd * bfd_ts_ref(const struct bfd *);
> +void bfd_ts_unref(struct bfd *);
> +int bfd_ts_get_status(struct bfd *, struct smap *);
> +bool bfd_ts_forwarding(struct bfd *);
> +void bfd_ts_run(struct bfd *);
> +void bfd_ts_wait(const struct bfd *);
> +long long int bfd_ts_wake_time(const struct bfd *);
> +
> +bool bfd_ts_should_send_packet(struct bfd *);
> +void bfd_ts_put_packet(struct bfd *, struct ofpbuf *,
> +                       uint8_t eth_src[ETH_ADDR_LEN]);
> +bool bfd_ts_should_process_packet(struct bfd *, const struct flow *,
> +                                  struct flow_wildcards *);
> +int bfd_ts_process_packet(struct bfd *, const struct flow *,
> +                          const struct ofpbuf *);
> +
> +#endif /* bfd_thread-safe.h */
> diff --git a/ofproto/ofproto-dpif-monitor.c
> b/ofproto/ofproto-dpif-monitor.c
> index b521735..aa20547 100644
> --- a/ofproto/ofproto-dpif-monitor.c
> +++ b/ofproto/ofproto-dpif-monitor.c
> @@ -19,7 +19,7 @@
>
>  #include <string.h>
>
> -#include "bfd.h"
> +#include "bfd_ts.h"
>  #include "cfm.h"
>  #include "hash.h"
>  #include "heap.h"
> @@ -140,8 +140,8 @@ mport_update(struct mport *mport, struct bfd *bfd,
> struct cfm *cfm,
>          mport->cfm = cfm_ref(cfm);
>      }
>      if (mport->bfd != bfd) {
> -        bfd_unref(mport->bfd);
> -        mport->bfd = bfd_ref(bfd);
> +        bfd_ts_unref(mport->bfd);
> +        mport->bfd = bfd_ts_ref(bfd);
>      }
>      if (hw_addr && memcmp(mport->hw_addr, hw_addr, ETH_ADDR_LEN)) {
>          memcpy(mport->hw_addr, hw_addr, ETH_ADDR_LEN);
> @@ -198,9 +198,9 @@ monitor_run(void)
>              cfm_compose_ccm(mport->cfm, &packet, mport->hw_addr);
>              ofproto_dpif_send_packet(mport->ofport, &packet);
>          }
> -        if (mport->bfd && bfd_should_send_packet(mport->bfd)) {
> +        if (mport->bfd && bfd_ts_should_send_packet(mport->bfd)) {
>              ofpbuf_clear(&packet);
> -            bfd_put_packet(mport->bfd, &packet, mport->hw_addr);
> +            bfd_ts_put_packet(mport->bfd, &packet, mport->hw_addr);
>              ofproto_dpif_send_packet(mport->ofport, &packet);
>          }
>          if (mport->cfm) {
> @@ -208,11 +208,11 @@ monitor_run(void)
>              cfm_wait(mport->cfm);
>          }
>          if (mport->bfd) {
> -            bfd_run(mport->bfd);
> -            bfd_wait(mport->bfd);
> +            bfd_ts_run(mport->bfd);
> +            bfd_ts_wait(mport->bfd);
>          }
>          /* Computes the next wakeup time for this mport. */
> -        next_wake_time = MIN(bfd_wake_time(mport->bfd),
> +        next_wake_time = MIN(bfd_ts_wake_time(mport->bfd),
>                               cfm_wake_time(mport->cfm));
>          heap_change(&monitor_heap, &mport->heap_node,
>                      MSEC_TO_PRIO(next_wake_time));
> diff --git a/ofproto/ofproto-dpif-xlate.c b/ofproto/ofproto-dpif-xlate.c
> index eb4931e..edc4dd1 100644
> --- a/ofproto/ofproto-dpif-xlate.c
> +++ b/ofproto/ofproto-dpif-xlate.c
> @@ -18,7 +18,7 @@
>
>  #include <errno.h>
>
> -#include "bfd.h"
> +#include "bfd_ts.h"
>  #include "bitmap.h"
>  #include "bond.h"
>  #include "bundle.h"
> @@ -451,8 +451,8 @@ xlate_ofport_set(struct ofproto_dpif *ofproto, struct
> ofbundle *ofbundle,
>      }
>
>      if (xport->bfd != bfd) {
> -        bfd_unref(xport->bfd);
> -        xport->bfd = bfd_ref(bfd);
> +        bfd_ts_unref(xport->bfd);
> +        xport->bfd = bfd_ts_ref(bfd);
>      }
>
>      if (xport->peer) {
> @@ -515,7 +515,7 @@ xlate_ofport_remove(struct ofport_dpif *ofport)
>
>      netdev_close(xport->netdev);
>      cfm_unref(xport->cfm);
> -    bfd_unref(xport->bfd);
> +    bfd_ts_unref(xport->bfd);
>      free(xport);
>  }
>
> @@ -1641,11 +1641,13 @@ process_special(struct xlate_ctx *ctx, const
> struct flow *flow,
>              cfm_process_heartbeat(xport->cfm, packet);
>          }
>          return SLOW_CFM;
> -    } else if (xport->bfd && bfd_should_process_flow(xport->bfd, flow,
> wc)) {
> +    } else if (xport->bfd
> +               && bfd_ts_should_process_packet(xport->bfd, flow, wc)) {
>          if (packet) {
> -            bfd_process_packet(xport->bfd, flow, packet);
> +            bfd_ts_process_packet(xport->bfd, flow, packet);
> +
>              /* If POLL received, immediately sends FINAL back. */
> -            if (bfd_should_send_packet(xport->bfd)) {
> +            if (bfd_ts_should_send_packet(xport->bfd)) {
>                  if (xport->peer) {
>                      ofproto_dpif_monitor_port_send_soon(xport->ofport);
>                  } else {
> @@ -1741,7 +1743,8 @@ compose_output_action__(struct xlate_ctx *ctx,
> ofp_port_t ofp_port,
>              netdev_vport_inc_tx(xport->netdev, ctx->xin->resubmit_stats);
>              netdev_vport_inc_rx(peer->netdev, ctx->xin->resubmit_stats);
>              if (peer->bfd) {
> -                bfd_account_rx(peer->bfd, ctx->xin->resubmit_stats);
> +                bfd_ts_account_rx(peer->bfd,
> +                                  ctx->xin->resubmit_stats->n_packets);
>              }
>          }
>
> @@ -3066,7 +3069,8 @@ xlate_actions__(struct xlate_in *xin, struct
> xlate_out *xout)
>      if (in_port && in_port->is_tunnel && ctx.xin->resubmit_stats) {
>          netdev_vport_inc_rx(in_port->netdev, ctx.xin->resubmit_stats);
>          if (in_port->bfd) {
> -            bfd_account_rx(in_port->bfd, ctx.xin->resubmit_stats);
> +            bfd_ts_account_rx(in_port->bfd,
> +                              ctx.xin->resubmit_stats->n_packets);
>          }
>      }
>
> diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
> index 8c43ee9..60d50df 100644
> --- a/ofproto/ofproto-dpif.c
> +++ b/ofproto/ofproto-dpif.c
> @@ -21,7 +21,7 @@
>
>  #include <errno.h>
>
> -#include "bfd.h"
> +#include "bfd_ts.h"
>  #include "bond.h"
>  #include "bundle.h"
>  #include "byte-order.h"
> @@ -77,6 +77,7 @@ enum { N_TABLES = 255 };
>  enum { TBL_INTERNAL = N_TABLES - 1 };    /* Used for internal hidden
> rules. */
>  BUILD_ASSERT_DECL(N_TABLES >= 2 && N_TABLES <= 255);
>
> +struct bfd;
>  struct flow_miss;
>
>  struct rule_dpif {
> @@ -1573,9 +1574,6 @@ port_modified(struct ofport *port_)
>          cfm_set_netdev(port->cfm, port->up.netdev);
>      }
>
> -    if (port->bfd) {
> -        bfd_set_netdev(port->bfd, port->up.netdev);
> -    }
>
>      ofproto_dpif_monitor_port_update(port, port->bfd, port->cfm,
>                                       port->up.pp.hw_addr);
> @@ -1722,8 +1720,8 @@ set_bfd(struct ofport *ofport_, const struct smap
> *cfg)
>      struct bfd *old;
>
>      old = ofport->bfd;
> -    ofport->bfd = bfd_configure(old, netdev_get_name(ofport->up.netdev),
> -                                cfg, ofport->up.netdev);
> +    ofport->bfd = bfd_ts_configure(old,
> netdev_get_name(ofport->up.netdev),
> +                                   cfg);
>      if (ofport->bfd != old) {
>          ofproto->backer->need_revalidate = REV_RECONFIGURE;
>      }
> @@ -1737,12 +1735,7 @@ get_bfd_status(struct ofport *ofport_, struct smap
> *smap)
>  {
>      struct ofport_dpif *ofport = ofport_dpif_cast(ofport_);
>
> -    if (ofport->bfd) {
> -        bfd_get_status(ofport->bfd, smap);
> -        return 0;
> -    } else {
> -        return ENOENT;
> -    }
> +    return bfd_ts_get_status(ofport->bfd, smap);
>  }
>
>  /* Spanning Tree. */
> @@ -2648,7 +2641,7 @@ port_run(struct ofport_dpif *ofport)
>      }
>
>      if (ofport->bfd) {
> -        bfd_enable = bfd_forwarding(ofport->bfd);
> +        bfd_enable = bfd_ts_forwarding(ofport->bfd);
>      }
>
>      if (ofport->bfd || ofport->cfm) {
> --
> 1.7.9.5
>
>
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