When there is no incoming data traffic at the interface for a period,
BFD decay allows the bfd session to increase the min_rx. This is
helpful in that some interfaces usually idle for long time. And cpu
consumption can be reduced by processing fewer bfd control packets.
Signed-off-by: Alex Wang <al...@nicira.com>
---
v3 -> v4:
- fix two bugs:
1. should reset bfd->decay_min_rx when min_rx is reconfigured.
2. should reset bfd->min_rx to bfd->cfg_min_rx when min_rx is
reconfigured and bfd->min_rx == bfd->decay_min_rx.
v2 -> v3:
- fix two bugs found in unit tests:
1. should reset the decay_detect_time every time
decay_min_rx is reconfigured.
2. error in calling netdev_close() after free(bfd).
v1 -> v2:
- remove bfd:decay_enable option, only use bfd:decay_min_rx.
- add bfd_set_netdev() function.
- reset decay_min_rx when itself or min_rx is reconfigured.
- use bfd_poll() to update the decay changes.
- refine the code as suggested by Ethan.
---
lib/bfd.c | 102 +++++++++++++++++++++++++++++++++++++++++++++---
lib/bfd.h | 5 ++-
ofproto/ofproto-dpif.c | 7 +++-
vswitchd/vswitch.xml | 10 +++++
4 files changed, 117 insertions(+), 7 deletions(-)
diff --git a/lib/bfd.c b/lib/bfd.c
index aa1a3f7..a98ccbd 100644
--- a/lib/bfd.c
+++ b/lib/bfd.c
@@ -24,6 +24,7 @@
#include "hash.h"
#include "hmap.h"
#include "list.h"
+#include "netdev.h"
#include "netlink.h"
#include "odp-util.h"
#include "ofpbuf.h"
@@ -152,6 +153,9 @@ struct bfd {
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. */
@@ -182,6 +186,10 @@ struct bfd {
int ref_cnt;
int forwarding_override; /* Manual override of 'forwarding' status. */
+
+ /* BFD decay related variables. */
+ int decay_min_rx;
+ long long int decay_detect_time; /* Decay detection time. */
};
static bool bfd_in_poll(const struct bfd *);
@@ -191,6 +199,8 @@ static const char *bfd_state_str(enum state);
static long long int bfd_min_tx(const struct bfd *);
static long long int bfd_tx_interval(const struct bfd *);
static long long int bfd_rx_interval(const struct bfd *);
+static uint64_t bfd_rx_packets(const struct bfd *);
+static void bfd_decay(struct bfd *);
static void bfd_set_next_tx(struct bfd *);
static void bfd_set_state(struct bfd *, enum state, enum diag);
static uint32_t generate_discriminator(void);
@@ -242,12 +252,13 @@ bfd_get_status(const struct bfd *bfd, struct smap *smap)
* 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)
+bfd_configure(struct bfd *bfd, const char *name, const struct smap *cfg,
+ struct netdev *netdev)
{
static uint16_t udp_src = 0;
static bool init = false;
+ int decay_min_rx;
long long int min_tx, min_rx;
bool cpath_down;
@@ -276,6 +287,9 @@ bfd_configure(struct bfd *bfd, const char *name,
bfd->min_tx = 1000;
bfd->mult = 3;
bfd->ref_cnt = 1;
+ bfd->netdev = netdev_ref(netdev);
+ bfd->decay_detect_time = 0;
+ bfd->rx_packets = bfd_rx_packets(bfd);
/* RFC 5881 section 4
* The source port MUST be in the range 49152 through 65535. The same
@@ -303,9 +317,26 @@ bfd_configure(struct bfd *bfd, const char *name,
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_in_poll(bfd) && bfd->cfg_min_rx > bfd->min_rx)
+ || bfd->min_rx == bfd->decay_min_rx) {
bfd->min_rx = bfd->cfg_min_rx;
}
+ bfd->decay_min_rx = 0;
+ bfd_poll(bfd);
+ }
+
+ decay_min_rx = smap_get_int(cfg, "decay_min_rx", 0);
+ if (bfd->decay_min_rx != decay_min_rx ) {
+ 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;
+ }
+ bfd->min_rx = bfd->cfg_min_rx;
+ bfd->decay_detect_time = (bfd->decay_min_rx < 2000 ?
+ 2000 : bfd->decay_min_rx) + time_msec();
bfd_poll(bfd);
}
@@ -338,6 +369,7 @@ bfd_unref(struct bfd *bfd)
ovs_assert(bfd->ref_cnt > 0);
if (!--bfd->ref_cnt) {
hmap_remove(&all_bfds, &bfd->node);
+ netdev_close(bfd->netdev);
free(bfd->name);
free(bfd);
}
@@ -360,11 +392,23 @@ bfd_wait(const struct bfd *bfd)
void
bfd_run(struct bfd *bfd)
{
- if (bfd->state > STATE_DOWN && time_msec() >= bfd->detect_time) {
+ long long int now = time_msec();
+
+ if (bfd->state > STATE_DOWN && now >= bfd->detect_time) {
bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED);
}
+ if (bfd->state == STATE_UP && bfd->decay_min_rx > 0
+ && now >= bfd->decay_detect_time) {
+ bfd_decay(bfd);
+ }
+
if (bfd->min_tx != bfd->cfg_min_tx || bfd->min_rx != bfd->cfg_min_rx) {
+ /* Do not poll if already decayed to decay_min_rx. */
+ if (bfd->state == STATE_UP && bfd->poll_min_rx == bfd->decay_min_rx
+ && bfd->min_tx == bfd->cfg_min_tx) {
+ return;
+ }
bfd_poll(bfd);
}
}
@@ -616,6 +660,17 @@ bfd_process_packet(struct bfd *bfd, const struct flow
*flow,
}
/* XXX: RFC 5880 Section 6.8.6 Demand mode related calculations here. */
}
+
+/* Must be called when the netdev owned by 'bfd' should change. */
+void
+bfd_set_netdev(struct bfd *bfd, const struct netdev *netdev)
+{
+ if (bfd->netdev != netdev) {
+ netdev_close(bfd->netdev);
+ bfd->netdev = netdev_ref(netdev);
+ }
+}
+
/* Helpers. */
static bool
@@ -630,7 +685,8 @@ 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->cfg_min_rx;
+ bfd->poll_min_rx = bfd->min_rx == bfd->decay_min_rx
+ ? 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);
@@ -804,6 +860,42 @@ bfd_set_state(struct bfd *bfd, enum state state, enum diag
diag)
}
}
+static uint64_t
+bfd_rx_packets(const struct bfd *bfd)
+{
+ struct netdev_stats stats;
+
+ if (!netdev_get_stats(bfd->netdev, &stats)) {
+ return stats.rx_packets;
+ } else {
+ return 0;
+ }
+}
+
+static void
+bfd_decay(struct bfd *bfd)
+{
+ uint64_t rx_packets = bfd_rx_packets(bfd);
+ int64_t diff;
+
+ diff = rx_packets - bfd->rx_packets;
+ bfd->rx_packets = rx_packets;
+ bfd->decay_detect_time = (bfd->decay_min_rx < 2000 ?
+ 2000 : bfd->decay_min_rx) + time_msec();
+
+ if (diff <= (bfd->decay_min_rx / bfd->min_rx + 5)) {
+ /* Decay when there is no obvious data traffic. */
+ if (bfd->min_rx != bfd->decay_min_rx) {
+ bfd->min_rx = bfd->decay_min_rx;
+ }
+ } else {
+ /* Restore the min_rx. */
+ if (bfd->min_rx != bfd->cfg_min_rx) {
+ bfd->min_rx = bfd->cfg_min_rx;
+ }
+ }
+}
+
static uint32_t
generate_discriminator(void)
{
diff --git a/lib/bfd.h b/lib/bfd.h
index ab854d8..db652e1 100644
--- a/lib/bfd.h
+++ b/lib/bfd.h
@@ -24,6 +24,7 @@
struct bfd;
struct flow;
struct flow_wildcards;
+struct netdev;
struct ofpbuf;
struct smap;
@@ -39,11 +40,13 @@ 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);
+ const struct smap *smap,
+ struct netdev *netdev);
struct bfd *bfd_ref(const struct bfd *);
void bfd_unref(struct bfd *);
bool bfd_forwarding(const struct bfd *);
void bfd_get_status(const struct bfd *, struct smap *);
+void bfd_set_netdev(struct bfd *, const struct netdev *);
#endif /* bfd.h */
diff --git a/ofproto/ofproto-dpif.c b/ofproto/ofproto-dpif.c
index 67e6c7a..63e4299 100644
--- a/ofproto/ofproto-dpif.c
+++ b/ofproto/ofproto-dpif.c
@@ -1748,6 +1748,10 @@ port_modified(struct ofport *port_)
cfm_set_netdev(port->cfm, port->up.netdev);
}
+ if (port->bfd) {
+ bfd_set_netdev(port->bfd, port->up.netdev);
+ }
+
if (port->is_tunnel && tnl_port_reconfigure(port, port->up.netdev,
port->odp_port)) {
ofproto_dpif_cast(port->up.ofproto)->backer->need_revalidate =
@@ -1882,7 +1886,8 @@ 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->bfd = bfd_configure(old, netdev_get_name(ofport->up.netdev),
+ cfg, ofport->up.netdev);
if (ofport->bfd != old) {
ofproto->backer->need_revalidate = REV_RECONFIGURE;
}
diff --git a/vswitchd/vswitch.xml b/vswitchd/vswitch.xml
index 3385912..f2ea326 100644
--- a/vswitchd/vswitch.xml
+++ b/vswitchd/vswitch.xml
@@ -1880,6 +1880,16 @@
specified. Defaults to <code>100</code>.
</column>
+ <column name="bfd" key="decay_min_rx" type='{"type": "integer"}'>
+ <code>decay_min_rx</code> is used to set the <code>min_rx</code>,
+ when there is no obvious incoming data traffic at the interface.
+ It cannot be less than the <code>min_rx</code>. The decay feature
+ is disable by setting the <code>decay_min_rx</code> to 0. And the
+ feature is reset everytime itself or <code>min_rx</code> is
+ reconfigured.
+ </column>
+
+
<column name="bfd" key="cpath_down" type='{"type": "boolean"}'>
Concatenated path down may be used when the local system should not
have traffic forwarded to it for some reason other than a connectivty
--
1.7.9.5
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