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/*
* Copyright (c) 2008, 2009, 2010, 2011 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 "bond.h"
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include "coverage.h"
#include "dynamic-string.h"
#include "flow.h"
#include "hmap.h"
#include "lacp.h"
#include "list.h"
#include "netdev.h"
#include "odp-util.h"
#include "ofpbuf.h"
#include "packets.h"
#include "poll-loop.h"
#include "shash.h"
#include "tag.h"
#include "timeval.h"
#include "unixctl.h"
#include "vlog.h"
VLOG_DEFINE_THIS_MODULE(bond);
/* Bit-mask for hashing a flow down to a bucket.
* There are (BOND_MASK + 1) buckets. */
#define BOND_MASK 0xff
/* A hash bucket for mapping a flow to a slave.
* "struct bond" has an array of (BOND_MASK + 1) of these. */
struct bond_entry {
struct bond_slave *slave; /* Assigned slave, NULL if unassigned. */
uint64_t tx_bytes; /* Count of bytes recently transmitted. */
tag_type tag; /* Tag for entry<->slave association. */
struct list list_node; /* In bond_slave's 'entries' list. */
};
/* A bond slave, that is, one of the links comprising a bond. */
struct bond_slave {
struct hmap_node hmap_node; /* In struct bond's slaves hmap. */
struct bond *bond; /* The bond that contains this slave. */
void *aux; /* Client-provided handle for this slave. */
struct netdev *netdev; /* Network device, owned by the client. */
unsigned int change_seq; /* Tracks changes in 'netdev'. */
char *name; /* Name (a copy of netdev_get_name(netdev)). */
/* Link status. */
long long delay_expires; /* Time after which 'enabled' may change. */
bool enabled; /* May be chosen for flows? */
bool may_enable; /* Client considers this slave bondable. */
tag_type tag; /* Tag associated with this slave. */
/* Rebalancing info. Used only by bond_rebalance(). */
struct list bal_node; /* In bond_rebalance()'s 'bals' list. */
struct list entries; /* 'struct bond_entry's assigned here. */
uint64_t tx_bytes; /* Sum across 'tx_bytes' of entries. */
/* BM_STABLE specific bonding info. */
uint32_t stb_id; /* ID used for 'stb_slaves' ordering. */
};
/* A bond, that is, a set of network devices grouped to improve performance or
* robustness. */
struct bond {
struct hmap_node hmap_node; /* In 'all_bonds' hmap. */
char *name; /* Name provided by client. */
/* Slaves. */
struct hmap slaves;
/* Bonding info. */
enum bond_mode balance; /* Balancing mode, one of BM_*. */
struct bond_slave *active_slave;
tag_type no_slaves_tag; /* Tag for flows when all slaves disabled. */
int updelay, downdelay; /* Delay before slave goes up/down, in ms. */
enum lacp_status lacp_status; /* Status of LACP negotiations. */
bool bond_revalidate; /* True if flows need revalidation. */
uint32_t basis; /* Basis for flow hash function. */
/* SLB specific bonding info. */
struct bond_entry *hash; /* An array of (BOND_MASK + 1) elements. */
int rebalance_interval; /* Interval between rebalances, in ms. */
long long int next_rebalance; /* Next rebalancing time. */
bool send_learning_packets;
/* BM_STABLE specific bonding info. */
tag_type stb_tag; /* Tag associated with this bond. */
/* Legacy compatibility. */
long long int next_fake_iface_update; /* LLONG_MAX if disabled. */
/* Tag set saved for next bond_run(). This tag set is a kluge for cases
* where we can't otherwise provide revalidation feedback to the client.
* That's only unixctl commands now; I hope no other cases will arise. */
struct tag_set unixctl_tags;
};
static struct hmap all_bonds = HMAP_INITIALIZER(&all_bonds);
static void bond_entry_reset(struct bond *);
static struct bond_slave *bond_slave_lookup(struct bond *, const void *slave_);
static void bond_enable_slave(struct bond_slave *, bool enable,
struct tag_set *);
static void bond_link_status_update(struct bond_slave *, struct tag_set *);
static void bond_choose_active_slave(struct bond *, struct tag_set *);
static unsigned int bond_hash_src(const uint8_t mac[ETH_ADDR_LEN],
uint16_t vlan, uint32_t basis);
static unsigned int bond_hash_tcp(const struct flow *, uint16_t vlan,
uint32_t basis);
static struct bond_entry *lookup_bond_entry(const struct bond *,
const struct flow *,
uint16_t vlan);
static tag_type bond_get_active_slave_tag(const struct bond *);
static struct bond_slave *choose_output_slave(const struct bond *,
const struct flow *,
uint16_t vlan);
static void bond_update_fake_slave_stats(struct bond *);
/* Attempts to parse 's' as the name of a bond balancing mode. If successful,
* stores the mode in '*balance' and returns true. Otherwise returns false
* without modifying '*balance'. */
bool
bond_mode_from_string(enum bond_mode *balance, const char *s)
{
if (!strcmp(s, bond_mode_to_string(BM_TCP))) {
*balance = BM_TCP;
} else if (!strcmp(s, bond_mode_to_string(BM_SLB))) {
*balance = BM_SLB;
} else if (!strcmp(s, bond_mode_to_string(BM_STABLE))) {
*balance = BM_STABLE;
} else if (!strcmp(s, bond_mode_to_string(BM_AB))) {
*balance = BM_AB;
} else {
return false;
}
return true;
}
/* Returns a string representing 'balance'. */
const char *
bond_mode_to_string(enum bond_mode balance) {
switch (balance) {
case BM_TCP:
return "balance-tcp";
case BM_SLB:
return "balance-slb";
case BM_STABLE:
return "stable";
case BM_AB:
return "active-backup";
}
NOT_REACHED();
}
/* Creates and returns a new bond whose configuration is initially taken from
* 's'.
*
* The caller should register each slave on the new bond by calling
* bond_slave_register(). */
struct bond *
bond_create(const struct bond_settings *s)
{
struct bond *bond;
bond = xzalloc(sizeof *bond);
hmap_init(&bond->slaves);
bond->no_slaves_tag = tag_create_random();
bond->stb_tag = tag_create_random();
bond->next_fake_iface_update = LLONG_MAX;
bond_reconfigure(bond, s);
tag_set_init(&bond->unixctl_tags);
return bond;
}
/* Frees 'bond'. */
void
bond_destroy(struct bond *bond)
{
struct bond_slave *slave, *next_slave;
if (!bond) {
return;
}
hmap_remove(&all_bonds, &bond->hmap_node);
HMAP_FOR_EACH_SAFE (slave, next_slave, hmap_node, &bond->slaves) {
hmap_remove(&bond->slaves, &slave->hmap_node);
/* Client owns 'slave->netdev'. */
free(slave->name);
free(slave);
}
hmap_destroy(&bond->slaves);
free(bond->hash);
free(bond->name);
free(bond);
}
/* Updates 'bond''s overall configuration to 's'.
*
* The caller should register each slave on 'bond' by calling
* bond_slave_register(). This is optional if none of the slaves'
* configuration has changed. In any case it can't hurt.
*
* Returns true if the configuration has changed in such a way that requires
* flow revalidation.
* */
bool
bond_reconfigure(struct bond *bond, const struct bond_settings *s)
{
bool revalidate = false;
if (!bond->name || strcmp(bond->name, s->name)) {
if (bond->name) {
hmap_remove(&all_bonds, &bond->hmap_node);
free(bond->name);
}
bond->name = xstrdup(s->name);
hmap_insert(&all_bonds, &bond->hmap_node, hash_string(bond->name, 0));
}
bond->updelay = s->up_delay;
bond->downdelay = s->down_delay;
if (bond->rebalance_interval != s->rebalance_interval) {
bond->rebalance_interval = s->rebalance_interval;
revalidate = true;
}
if (bond->balance != s->balance) {
bond->balance = s->balance;
revalidate = true;
}
if (bond->basis != s->basis) {
bond->basis = s->basis;
revalidate = true;
}
if (s->fake_iface) {
if (bond->next_fake_iface_update == LLONG_MAX) {
bond->next_fake_iface_update = time_msec();
}
} else {
bond->next_fake_iface_update = LLONG_MAX;
}
if (bond->bond_revalidate) {
revalidate = true;
bond->bond_revalidate = false;
}
if (bond->balance == BM_AB || !bond->hash || revalidate) {
bond_entry_reset(bond);
}
return revalidate;
}
static void
bond_slave_set_netdev__(struct bond_slave *slave, struct netdev *netdev)
{
if (slave->netdev != netdev) {
slave->netdev = netdev;
slave->change_seq = 0;
}
}
/* Registers 'slave_' as a slave of 'bond'. The 'slave_' pointer is an
* arbitrary client-provided pointer that uniquely identifies a slave within a
* bond. If 'slave_' already exists within 'bond' then this function
* reconfigures the existing slave.
*
* 'stb_id' is used in BM_STABLE bonds to guarantee consistent slave choices
* across restarts and distributed vswitch instances. It should be unique per
* slave, and preferably consistent across restarts and reconfigurations.
*
* 'netdev' must be the network device that 'slave_' represents. It is owned
* by the client, so the client must not close it before either unregistering
* 'slave_' or destroying 'bond'.
*/
void
bond_slave_register(struct bond *bond, void *slave_, uint32_t stb_id,
struct netdev *netdev)
{
struct bond_slave *slave = bond_slave_lookup(bond, slave_);
if (!slave) {
slave = xzalloc(sizeof *slave);
hmap_insert(&bond->slaves, &slave->hmap_node, hash_pointer(slave_, 0));
slave->bond = bond;
slave->aux = slave_;
slave->delay_expires = LLONG_MAX;
slave->name = xstrdup(netdev_get_name(netdev));
bond->bond_revalidate = true;
slave->enabled = false;
bond_enable_slave(slave, netdev_get_carrier(netdev), NULL);
}
if (slave->stb_id != stb_id) {
slave->stb_id = stb_id;
bond->bond_revalidate = true;
}
bond_slave_set_netdev__(slave, netdev);
free(slave->name);
slave->name = xstrdup(netdev_get_name(netdev));
}
/* Updates the network device to be used with 'slave_' to 'netdev'.
*
* This is useful if the caller closes and re-opens the network device
* registered with bond_slave_register() but doesn't need to change anything
* else. */
void
bond_slave_set_netdev(struct bond *bond, void *slave_, struct netdev *netdev)
{
struct bond_slave *slave = bond_slave_lookup(bond, slave_);
if (slave) {
bond_slave_set_netdev__(slave, netdev);
}
}
/* Unregisters 'slave_' from 'bond'. If 'bond' does not contain such a slave
* then this function has no effect.
*
* Unregistering a slave invalidates all flows. */
void
bond_slave_unregister(struct bond *bond, const void *slave_)
{
struct bond_slave *slave = bond_slave_lookup(bond, slave_);
bool del_active;
if (!slave) {
return;
}
bond_enable_slave(slave, false, NULL);
del_active = bond->active_slave == slave;
if (bond->hash) {
struct bond_entry *e;
for (e = bond->hash; e <= &bond->hash[BOND_MASK]; e++) {
if (e->slave == slave) {
e->slave = NULL;
}
}
}
free(slave->name);
hmap_remove(&bond->slaves, &slave->hmap_node);
/* Client owns 'slave->netdev'. */
free(slave);
if (del_active) {
struct tag_set tags;
tag_set_init(&tags);
bond_choose_active_slave(bond, &tags);
bond->send_learning_packets = true;
}
}
/* Should be called on each slave in 'bond' before bond_run() to indicate
* whether or not 'slave_' may be enabled. This function is intended to allow
* other protocols to have some impact on bonding decisions. For example LACP
* or high level link monitoring protocols may decide that a given slave should
* not be able to send traffic. */
void
bond_slave_set_may_enable(struct bond *bond, void *slave_, bool may_enable)
{
bond_slave_lookup(bond, slave_)->may_enable = may_enable;
}
/* Performs periodic maintenance on 'bond'. The caller must provide 'tags' to
* allow tagged flows to be invalidated.
*
* The caller should check bond_should_send_learning_packets() afterward. */
void
bond_run(struct bond *bond, struct tag_set *tags, enum lacp_status lacp_status)
{
struct bond_slave *slave;
if (bond->lacp_status != lacp_status) {
bond->lacp_status = lacp_status;
bond->bond_revalidate = true;
}
/* Enable slaves based on link status and LACP feedback. */
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
bond_link_status_update(slave, tags);
slave->change_seq = netdev_change_seq(slave->netdev);
}
if (!bond->active_slave || !bond->active_slave->enabled) {
bond_choose_active_slave(bond, tags);
}
/* Update fake bond interface stats. */
if (time_msec() >= bond->next_fake_iface_update) {
bond_update_fake_slave_stats(bond);
bond->next_fake_iface_update = time_msec() + 1000;
}
if (bond->bond_revalidate) {
bond->bond_revalidate = false;
bond_entry_reset(bond);
if (bond->balance != BM_STABLE) {
struct bond_slave *slave;
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
tag_set_add(tags, slave->tag);
}
} else {
tag_set_add(tags, bond->stb_tag);
}
tag_set_add(tags, bond->no_slaves_tag);
}
/* Invalidate any tags required by */
tag_set_union(tags, &bond->unixctl_tags);
tag_set_init(&bond->unixctl_tags);
}
/* Causes poll_block() to wake up when 'bond' needs something to be done. */
void
bond_wait(struct bond *bond)
{
struct bond_slave *slave;
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (slave->delay_expires != LLONG_MAX) {
poll_timer_wait_until(slave->delay_expires);
}
if (slave->change_seq != netdev_change_seq(slave->netdev)) {
poll_immediate_wake();
}
}
if (bond->next_fake_iface_update != LLONG_MAX) {
poll_timer_wait_until(bond->next_fake_iface_update);
}
/* Ensure that any saved tags get revalidated right away. */
if (!tag_set_is_empty(&bond->unixctl_tags)) {
poll_immediate_wake();
}
/* We don't wait for bond->next_rebalance because rebalancing can only run
* at a flow account checkpoint. ofproto does checkpointing on its own
* schedule and bond_rebalance() gets called afterward, so we'd just be
* waking up for no purpose. */
}
/* MAC learning table interaction. */
static bool
may_send_learning_packets(const struct bond *bond)
{
return bond->lacp_status == LACP_DISABLED
&& bond->balance != BM_STABLE
&& bond->active_slave;
}
/* Returns true if 'bond' needs the client to send out packets to assist with
* MAC learning on 'bond'. If this function returns true, then the client
* should iterate through its MAC learning table for the bridge on which 'bond'
* is located. For each MAC that has been learned on a port other than 'bond',
* it should call bond_compose_learning_packet().
*
* This function will only return true if 'bond' is in SLB mode and LACP is not
* negotiated. Otherwise sending learning packets isn't necessary.
*
* Calling this function resets the state that it checks. */
bool
bond_should_send_learning_packets(struct bond *bond)
{
bool send = bond->send_learning_packets && may_send_learning_packets(bond);
bond->send_learning_packets = false;
return send;
}
/* Sends a gratuitous learning packet on 'bond' from 'eth_src' on 'vlan'.
*
* See bond_should_send_learning_packets() for description of usage. The
* caller should send the composed packet on the port associated with
* port_aux and takes ownership of the returned ofpbuf. */
struct ofpbuf *
bond_compose_learning_packet(struct bond *bond,
const uint8_t eth_src[ETH_ADDR_LEN],
uint16_t vlan, void **port_aux)
{
struct bond_slave *slave;
struct ofpbuf *packet;
struct flow flow;
assert(may_send_learning_packets(bond));
memset(&flow, 0, sizeof flow);
memcpy(flow.dl_src, eth_src, ETH_ADDR_LEN);
slave = choose_output_slave(bond, &flow, vlan);
packet = ofpbuf_new(0);
compose_rarp(packet, eth_src);
if (vlan) {
eth_push_vlan(packet, htons(vlan));
}
*port_aux = slave->aux;
return packet;
}
/* Checks whether a packet that arrived on 'slave_' within 'bond', with an
* Ethernet destination address of 'eth_dst', should be admitted.
*
* The return value is one of the following:
*
* - BV_ACCEPT: Admit the packet.
*
* - BV_DROP: Drop the packet.
*
* - BV_DROP_IF_MOVED: Consult the MAC learning table for the packet's
* Ethernet source address and VLAN. If there is none, or if the packet
* is on the learned port, then admit the packet. If a different port has
* been learned, however, drop the packet (and do not use it for MAC
* learning).
*/
enum bond_verdict
bond_check_admissibility(struct bond *bond, const void *slave_,
const uint8_t eth_dst[ETH_ADDR_LEN], tag_type *tags)
{
struct bond_slave *slave = bond_slave_lookup(bond, slave_);
/* LACP bonds have very loose admissibility restrictions because we can
* assume the remote switch is aware of the bond and will "do the right
* thing". However, as a precaution we drop packets on disabled slaves
* because no correctly implemented partner switch should be sending
* packets to them.
*
* If LACP is configured, but LACP negotiations have been unsuccessful, we
* drop all incoming traffic. */
switch (bond->lacp_status) {
case LACP_NEGOTIATED: return slave->enabled ? BV_ACCEPT : BV_DROP;
case LACP_CONFIGURED: return BV_DROP;
case LACP_DISABLED: break;
}
/* Drop all multicast packets on inactive slaves. */
if (eth_addr_is_multicast(eth_dst)) {
*tags |= bond_get_active_slave_tag(bond);
if (bond->active_slave != bond_slave_lookup(bond, slave_)) {
return BV_DROP;
}
}
switch (bond->balance) {
case BM_AB:
/* Drop all packets which arrive on backup slaves. This is similar to
* how Linux bonding handles active-backup bonds. */
*tags |= bond_get_active_slave_tag(bond);
if (bond->active_slave != slave) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
VLOG_DBG_RL(&rl, "active-backup bond received packet on backup"
" slave (%s) destined for " ETH_ADDR_FMT,
slave->name, ETH_ADDR_ARGS(eth_dst));
return BV_DROP;
}
return BV_ACCEPT;
case BM_TCP:
/* TCP balanced bonds require successful LACP negotiated. Based on the
* above check, LACP is off on this bond. Therfore, we drop all
* incoming traffic. */
return BV_DROP;
case BM_SLB:
/* Drop all packets for which we have learned a different input port,
* because we probably sent the packet on one slave and got it back on
* the other. Gratuitous ARP packets are an exception to this rule:
* the host has moved to another switch. The exception to the
* exception is if we locked the learning table to avoid reflections on
* bond slaves. */
return BV_DROP_IF_MOVED;
case BM_STABLE:
return BV_ACCEPT;
}
NOT_REACHED();
}
/* Returns the slave (registered on 'bond' by bond_slave_register()) to which
* a packet with the given 'flow' and 'vlan' should be forwarded. Returns
* NULL if the packet should be dropped because no slaves are enabled.
*
* 'vlan' is not necessarily the same as 'flow->vlan_tci'. First, 'vlan'
* should be a VID only (i.e. excluding the PCP bits). Second,
* 'flow->vlan_tci' is the VLAN TCI that appeared on the packet (so it will be
* nonzero only for trunk ports), whereas 'vlan' is the logical VLAN that the
* packet belongs to (so for an access port it will be the access port's VLAN).
*
* Adds a tag to '*tags' that associates the flow with the returned slave.
*/
void *
bond_choose_output_slave(struct bond *bond, const struct flow *flow,
uint16_t vlan, tag_type *tags)
{
struct bond_slave *slave = choose_output_slave(bond, flow, vlan);
if (slave) {
*tags |= bond->balance == BM_STABLE ? bond->stb_tag : slave->tag;
return slave->aux;
} else {
*tags |= bond->no_slaves_tag;
return NULL;
}
}
/* Rebalancing. */
static bool
bond_is_balanced(const struct bond *bond)
{
return bond->rebalance_interval
&& (bond->balance == BM_SLB || bond->balance == BM_TCP);
}
/* Notifies 'bond' that 'n_bytes' bytes were sent in 'flow' within 'vlan'. */
void
bond_account(struct bond *bond, const struct flow *flow, uint16_t vlan,
uint64_t n_bytes)
{
if (bond_is_balanced(bond)) {
lookup_bond_entry(bond, flow, vlan)->tx_bytes += n_bytes;
}
}
static struct bond_slave *
bond_slave_from_bal_node(struct list *bal)
{
return CONTAINER_OF(bal, struct bond_slave, bal_node);
}
static void
log_bals(struct bond *bond, const struct list *bals)
{
if (VLOG_IS_DBG_ENABLED()) {
struct ds ds = DS_EMPTY_INITIALIZER;
const struct bond_slave *slave;
LIST_FOR_EACH (slave, bal_node, bals) {
if (ds.length) {
ds_put_char(&ds, ',');
}
ds_put_format(&ds, " %s %"PRIu64"kB",
slave->name, slave->tx_bytes / 1024);
if (!slave->enabled) {
ds_put_cstr(&ds, " (disabled)");
}
if (!list_is_empty(&slave->entries)) {
struct bond_entry *e;
ds_put_cstr(&ds, " (");
LIST_FOR_EACH (e, list_node, &slave->entries) {
if (&e->list_node != list_front(&slave->entries)) {
ds_put_cstr(&ds, " + ");
}
ds_put_format(&ds, "h%td: %"PRIu64"kB",
e - bond->hash, e->tx_bytes / 1024);
}
ds_put_cstr(&ds, ")");
}
}
VLOG_DBG("bond %s:%s", bond->name, ds_cstr(&ds));
ds_destroy(&ds);
}
}
/* Shifts 'hash' from its current slave to 'to'. */
static void
bond_shift_load(struct bond_entry *hash, struct bond_slave *to,
struct tag_set *set)
{
struct bond_slave *from = hash->slave;
struct bond *bond = from->bond;
uint64_t delta = hash->tx_bytes;
VLOG_INFO("bond %s: shift %"PRIu64"kB of load (with hash %td) "
"from %s to %s (now carrying %"PRIu64"kB and "
"%"PRIu64"kB load, respectively)",
bond->name, delta / 1024, hash - bond->hash,
from->name, to->name,
(from->tx_bytes - delta) / 1024,
(to->tx_bytes + delta) / 1024);
/* Shift load away from 'from' to 'to'. */
from->tx_bytes -= delta;
to->tx_bytes += delta;
/* Arrange for flows to be revalidated. */
tag_set_add(set, hash->tag);
hash->slave = to;
hash->tag = tag_create_random();
}
/* Pick and returns a bond_entry to migrate to 'to' (the least-loaded slave),
* given that doing so must decrease the ratio of the load on the two slaves by
* at least 0.1. Returns NULL if there is no appropriate entry.
*
* The list of entries isn't sorted. I don't know of a reason to prefer to
* shift away small hashes or large hashes. */
static struct bond_entry *
choose_entry_to_migrate(const struct bond_slave *from, uint64_t to_tx_bytes)
{
struct bond_entry *e;
if (list_is_short(&from->entries)) {
/* 'from' carries no more than one MAC hash, so shifting load away from
* it would be pointless. */
return NULL;
}
LIST_FOR_EACH (e, list_node, &from->entries) {
double old_ratio, new_ratio;
uint64_t delta;
if (to_tx_bytes == 0) {
/* Nothing on the new slave, move it. */
return e;
}
delta = e->tx_bytes;
old_ratio = (double)from->tx_bytes / to_tx_bytes;
new_ratio = (double)(from->tx_bytes - delta) / (to_tx_bytes + delta);
if (old_ratio - new_ratio > 0.1) {
/* Would decrease the ratio, move it. */
return e;
}
}
return NULL;
}
/* Inserts 'slave' into 'bals' so that descending order of 'tx_bytes' is
* maintained. */
static void
insert_bal(struct list *bals, struct bond_slave *slave)
{
struct bond_slave *pos;
LIST_FOR_EACH (pos, bal_node, bals) {
if (slave->tx_bytes > pos->tx_bytes) {
break;
}
}
list_insert(&pos->bal_node, &slave->bal_node);
}
/* Removes 'slave' from its current list and then inserts it into 'bals' so
* that descending order of 'tx_bytes' is maintained. */
static void
reinsert_bal(struct list *bals, struct bond_slave *slave)
{
list_remove(&slave->bal_node);
insert_bal(bals, slave);
}
/* If 'bond' needs rebalancing, does so.
*
* The caller should have called bond_account() for each active flow, to ensure
* that flow data is consistently accounted at this point. */
void
bond_rebalance(struct bond *bond, struct tag_set *tags)
{
struct bond_slave *slave;
struct bond_entry *e;
struct list bals;
if (!bond_is_balanced(bond) || time_msec() < bond->next_rebalance) {
return;
}
bond->next_rebalance = time_msec() + bond->rebalance_interval;
/* Add each bond_entry to its slave's 'entries' list.
* Compute each slave's tx_bytes as the sum of its entries' tx_bytes. */
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
slave->tx_bytes = 0;
list_init(&slave->entries);
}
for (e = &bond->hash[0]; e <= &bond->hash[BOND_MASK]; e++) {
if (e->slave && e->tx_bytes) {
e->slave->tx_bytes += e->tx_bytes;
list_push_back(&e->slave->entries, &e->list_node);
}
}
/* Add enabled slaves to 'bals' in descending order of tx_bytes.
*
* XXX This is O(n**2) in the number of slaves but it could be O(n lg n)
* with a proper list sort algorithm. */
list_init(&bals);
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (slave->enabled) {
insert_bal(&bals, slave);
}
}
log_bals(bond, &bals);
/* Shift load from the most-loaded slaves to the least-loaded slaves. */
while (!list_is_short(&bals)) {
struct bond_slave *from = bond_slave_from_bal_node(list_front(&bals));
struct bond_slave *to = bond_slave_from_bal_node(list_back(&bals));
uint64_t overload;
overload = from->tx_bytes - to->tx_bytes;
if (overload < to->tx_bytes >> 5 || overload < 100000) {
/* The extra load on 'from' (and all less-loaded slaves), compared
* to that of 'to' (the least-loaded slave), is less than ~3%, or
* it is less than ~1Mbps. No point in rebalancing. */
break;
}
/* 'from' is carrying significantly more load than 'to', and that load
* is split across at least two different hashes. */
e = choose_entry_to_migrate(from, to->tx_bytes);
if (e) {
bond_shift_load(e, to, tags);
/* Delete element from from->entries.
*
* We don't add the element to to->hashes. That would only allow
* 'e' to be migrated to another slave in this rebalancing run, and
* there is no point in doing that. */
list_remove(&e->list_node);
/* Re-sort 'bals'. */
reinsert_bal(&bals, from);
reinsert_bal(&bals, to);
} else {
/* Can't usefully migrate anything away from 'from'.
* Don't reconsider it. */
list_remove(&from->bal_node);
}
}
/* Implement exponentially weighted moving average. A weight of 1/2 causes
* historical data to decay to <1% in 7 rebalancing runs. 1,000,000 bytes
* take 20 rebalancing runs to decay to 0 and get deleted entirely. */
for (e = &bond->hash[0]; e <= &bond->hash[BOND_MASK]; e++) {
e->tx_bytes /= 2;
if (!e->tx_bytes) {
e->slave = NULL;
}
}
}
/* Bonding unixctl user interface functions. */
static struct bond *
bond_find(const char *name)
{
struct bond *bond;
HMAP_FOR_EACH_WITH_HASH (bond, hmap_node, hash_string(name, 0),
&all_bonds) {
if (!strcmp(bond->name, name)) {
return bond;
}
}
return NULL;
}
static struct bond_slave *
bond_lookup_slave(struct bond *bond, const char *slave_name)
{
struct bond_slave *slave;
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (!strcmp(slave->name, slave_name)) {
return slave;
}
}
return NULL;
}
static void
bond_unixctl_list(struct unixctl_conn *conn,
int argc OVS_UNUSED, const char *argv[] OVS_UNUSED,
void *aux OVS_UNUSED)
{
struct ds ds = DS_EMPTY_INITIALIZER;
const struct bond *bond;
ds_put_cstr(&ds, "bond\ttype\tslaves\n");
HMAP_FOR_EACH (bond, hmap_node, &all_bonds) {
const struct bond_slave *slave;
size_t i;
ds_put_format(&ds, "%s\t%s\t",
bond->name, bond_mode_to_string(bond->balance));
i = 0;
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (i++ > 0) {
ds_put_cstr(&ds, ", ");
}
ds_put_cstr(&ds, slave->name);
}
ds_put_char(&ds, '\n');
}
unixctl_command_reply(conn, ds_cstr(&ds));
ds_destroy(&ds);
}
static void
bond_print_details(struct ds *ds, const struct bond *bond)
{
struct shash slave_shash = SHASH_INITIALIZER(&slave_shash);
const struct shash_node **sorted_slaves = NULL;
const struct bond_slave *slave;
int i;
ds_put_format(ds, "---- %s ----\n", bond->name);
ds_put_format(ds, "bond_mode: %s\n",
bond_mode_to_string(bond->balance));
ds_put_format(ds, "bond-hash-basis: %"PRIu32"\n", bond->basis);
ds_put_format(ds, "updelay: %d ms\n", bond->updelay);
ds_put_format(ds, "downdelay: %d ms\n", bond->downdelay);
if (bond_is_balanced(bond)) {
ds_put_format(ds, "next rebalance: %lld ms\n",
bond->next_rebalance - time_msec());
}
ds_put_cstr(ds, "lacp_status: ");
switch (bond->lacp_status) {
case LACP_NEGOTIATED:
ds_put_cstr(ds, "negotiated\n");
break;
case LACP_CONFIGURED:
ds_put_cstr(ds, "configured\n");
break;
case LACP_DISABLED:
ds_put_cstr(ds, "off\n");
break;
default:
ds_put_cstr(ds, "<unknown>\n");
break;
}
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
shash_add(&slave_shash, slave->name, slave);
}
sorted_slaves = shash_sort(&slave_shash);
for (i = 0; i < shash_count(&slave_shash); i++) {
struct bond_entry *be;
slave = sorted_slaves[i]->data;
/* Basic info. */
ds_put_format(ds, "\nslave %s: %s\n",
slave->name, slave->enabled ? "enabled" : "disabled");
if (slave == bond->active_slave) {
ds_put_cstr(ds, "\tactive slave\n");
}
if (slave->delay_expires != LLONG_MAX) {
ds_put_format(ds, "\t%s expires in %lld ms\n",
slave->enabled ? "downdelay" : "updelay",
slave->delay_expires - time_msec());
}
ds_put_format(ds, "\tmay_enable: %s\n",
slave->may_enable ? "true" : "false");
if (!bond_is_balanced(bond)) {
continue;
}
/* Hashes. */
for (be = bond->hash; be <= &bond->hash[BOND_MASK]; be++) {
int hash = be - bond->hash;
if (be->slave != slave) {
continue;
}
ds_put_format(ds, "\thash %d: %"PRIu64" kB load\n",
hash, be->tx_bytes / 1024);
/* XXX How can we list the MACs assigned to hashes of SLB bonds? */
}
}
shash_destroy(&slave_shash);
free(sorted_slaves);
ds_put_cstr(ds, "\n");
}
static void
bond_unixctl_show(struct unixctl_conn *conn,
int argc, const char *argv[],
void *aux OVS_UNUSED)
{
struct ds ds = DS_EMPTY_INITIALIZER;
if (argc > 1) {
const struct bond *bond = bond_find(argv[1]);
if (!bond) {
unixctl_command_reply_error(conn, "no such bond");
return;
}
bond_print_details(&ds, bond);
} else {
const struct bond *bond;
HMAP_FOR_EACH (bond, hmap_node, &all_bonds) {
bond_print_details(&ds, bond);
}
}
unixctl_command_reply(conn, ds_cstr(&ds));
ds_destroy(&ds);
}
static void
bond_unixctl_migrate(struct unixctl_conn *conn,
int argc OVS_UNUSED, const char *argv[],
void *aux OVS_UNUSED)
{
const char *bond_s = argv[1];
const char *hash_s = argv[2];
const char *slave_s = argv[3];
struct bond *bond;
struct bond_slave *slave;
struct bond_entry *entry;
int hash;
bond = bond_find(bond_s);
if (!bond) {
unixctl_command_reply_error(conn, "no such bond");
return;
}
if (bond->balance != BM_SLB) {
unixctl_command_reply_error(conn, "not an SLB bond");
return;
}
if (strspn(hash_s, "0123456789") == strlen(hash_s)) {
hash = atoi(hash_s) & BOND_MASK;
} else {
unixctl_command_reply_error(conn, "bad hash");
return;
}
slave = bond_lookup_slave(bond, slave_s);
if (!slave) {
unixctl_command_reply_error(conn, "no such slave");
return;
}
if (!slave->enabled) {
unixctl_command_reply_error(conn, "cannot migrate to disabled slave");
return;
}
entry = &bond->hash[hash];
tag_set_add(&bond->unixctl_tags, entry->tag);
entry->slave = slave;
entry->tag = tag_create_random();
unixctl_command_reply(conn, "migrated");
}
static void
bond_unixctl_set_active_slave(struct unixctl_conn *conn,
int argc OVS_UNUSED, const char *argv[],
void *aux OVS_UNUSED)
{
const char *bond_s = argv[1];
const char *slave_s = argv[2];
struct bond *bond;
struct bond_slave *slave;
bond = bond_find(bond_s);
if (!bond) {
unixctl_command_reply_error(conn, "no such bond");
return;
}
slave = bond_lookup_slave(bond, slave_s);
if (!slave) {
unixctl_command_reply_error(conn, "no such slave");
return;
}
if (!slave->enabled) {
unixctl_command_reply_error(conn, "cannot make disabled slave active");
return;
}
if (bond->active_slave != slave) {
tag_set_add(&bond->unixctl_tags, bond_get_active_slave_tag(bond));
bond->active_slave = slave;
bond->active_slave->tag = tag_create_random();
VLOG_INFO("bond %s: active interface is now %s",
bond->name, slave->name);
bond->send_learning_packets = true;
unixctl_command_reply(conn, "done");
} else {
unixctl_command_reply(conn, "no change");
}
}
static void
enable_slave(struct unixctl_conn *conn, const char *argv[], bool enable)
{
const char *bond_s = argv[1];
const char *slave_s = argv[2];
struct bond *bond;
struct bond_slave *slave;
bond = bond_find(bond_s);
if (!bond) {
unixctl_command_reply_error(conn, "no such bond");
return;
}
slave = bond_lookup_slave(bond, slave_s);
if (!slave) {
unixctl_command_reply_error(conn, "no such slave");
return;
}
bond_enable_slave(slave, enable, &bond->unixctl_tags);
unixctl_command_reply(conn, enable ? "enabled" : "disabled");
}
static void
bond_unixctl_enable_slave(struct unixctl_conn *conn,
int argc OVS_UNUSED, const char *argv[],
void *aux OVS_UNUSED)
{
enable_slave(conn, argv, true);
}
static void
bond_unixctl_disable_slave(struct unixctl_conn *conn,
int argc OVS_UNUSED, const char *argv[],
void *aux OVS_UNUSED)
{
enable_slave(conn, argv, false);
}
static void
bond_unixctl_hash(struct unixctl_conn *conn, int argc, const char *argv[],
void *aux OVS_UNUSED)
{
const char *mac_s = argv[1];
const char *vlan_s = argc > 2 ? argv[2] : NULL;
const char *basis_s = argc > 3 ? argv[3] : NULL;
uint8_t mac[ETH_ADDR_LEN];
uint8_t hash;
char *hash_cstr;
unsigned int vlan;
uint32_t basis;
if (vlan_s) {
if (sscanf(vlan_s, "%u", &vlan) != 1) {
unixctl_command_reply_error(conn, "invalid vlan");
return;
}
} else {
vlan = 0;
}
if (basis_s) {
if (sscanf(basis_s, "%"PRIu32, &basis) != 1) {
unixctl_command_reply_error(conn, "invalid basis");
return;
}
} else {
basis = 0;
}
if (sscanf(mac_s, ETH_ADDR_SCAN_FMT, ETH_ADDR_SCAN_ARGS(mac))
== ETH_ADDR_SCAN_COUNT) {
hash = bond_hash_src(mac, vlan, basis) & BOND_MASK;
hash_cstr = xasprintf("%u", hash);
unixctl_command_reply(conn, hash_cstr);
free(hash_cstr);
} else {
unixctl_command_reply_error(conn, "invalid mac");
}
}
void
bond_init(void)
{
unixctl_command_register("bond/list", "", 0, 0, bond_unixctl_list, NULL);
unixctl_command_register("bond/show", "[port]", 0, 1, bond_unixctl_show,
NULL);
unixctl_command_register("bond/migrate", "port hash slave", 3, 3,
bond_unixctl_migrate, NULL);
unixctl_command_register("bond/set-active-slave", "port slave", 2, 2,
bond_unixctl_set_active_slave, NULL);
unixctl_command_register("bond/enable-slave", "port slave", 2, 2,
bond_unixctl_enable_slave, NULL);
unixctl_command_register("bond/disable-slave", "port slave", 2, 2,
bond_unixctl_disable_slave, NULL);
unixctl_command_register("bond/hash", "mac [vlan] [basis]", 1, 3,
bond_unixctl_hash, NULL);
}
static void
bond_entry_reset(struct bond *bond)
{
if (bond->balance != BM_AB) {
size_t hash_len = (BOND_MASK + 1) * sizeof *bond->hash;
if (!bond->hash) {
bond->hash = xmalloc(hash_len);
}
memset(bond->hash, 0, hash_len);
bond->next_rebalance = time_msec() + bond->rebalance_interval;
} else {
free(bond->hash);
bond->hash = NULL;
}
}
static struct bond_slave *
bond_slave_lookup(struct bond *bond, const void *slave_)
{
struct bond_slave *slave;
HMAP_FOR_EACH_IN_BUCKET (slave, hmap_node, hash_pointer(slave_, 0),
&bond->slaves) {
if (slave->aux == slave_) {
return slave;
}
}
return NULL;
}
static void
bond_enable_slave(struct bond_slave *slave, bool enable, struct tag_set *tags)
{
struct bond *bond = slave->bond;
slave->delay_expires = LLONG_MAX;
if (enable != slave->enabled) {
slave->enabled = enable;
if (!slave->enabled) {
VLOG_WARN("interface %s: disabled", slave->name);
if (tags) {
tag_set_add(tags, slave->tag);
}
} else {
VLOG_WARN("interface %s: enabled", slave->name);
slave->tag = tag_create_random();
}
if (bond->balance == BM_STABLE) {
bond->bond_revalidate = true;
}
}
}
static void
bond_link_status_update(struct bond_slave *slave, struct tag_set *tags)
{
struct bond *bond = slave->bond;
bool up;
up = netdev_get_carrier(slave->netdev) && slave->may_enable;
if ((up == slave->enabled) != (slave->delay_expires == LLONG_MAX)) {
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
VLOG_INFO_RL(&rl, "interface %s: link state %s",
slave->name, up ? "up" : "down");
if (up == slave->enabled) {
slave->delay_expires = LLONG_MAX;
VLOG_INFO_RL(&rl, "interface %s: will not be %s",
slave->name, up ? "disabled" : "enabled");
} else {
int delay = (bond->lacp_status != LACP_DISABLED ? 0
: up ? bond->updelay : bond->downdelay);
slave->delay_expires = time_msec() + delay;
if (delay) {
VLOG_INFO_RL(&rl, "interface %s: will be %s if it stays %s "
"for %d ms",
slave->name,
up ? "enabled" : "disabled",
up ? "up" : "down",
delay);
}
}
}
if (time_msec() >= slave->delay_expires) {
bond_enable_slave(slave, up, tags);
}
}
static unsigned int
bond_hash_src(const uint8_t mac[ETH_ADDR_LEN], uint16_t vlan, uint32_t basis)
{
return hash_3words(hash_bytes(mac, ETH_ADDR_LEN, 0), vlan, basis);
}
static unsigned int
bond_hash_tcp(const struct flow *flow, uint16_t vlan, uint32_t basis)
{
struct flow hash_flow = *flow;
hash_flow.vlan_tci = htons(vlan);
/* The symmetric quality of this hash function is not required, but
* flow_hash_symmetric_l4 already exists, and is sufficient for our
* purposes, so we use it out of convenience. */
return flow_hash_symmetric_l4(&hash_flow, basis);
}
static unsigned int
bond_hash(const struct bond *bond, const struct flow *flow, uint16_t vlan)
{
assert(bond->balance == BM_TCP || bond->balance == BM_SLB);
return (bond->balance == BM_TCP
? bond_hash_tcp(flow, vlan, bond->basis)
: bond_hash_src(flow->dl_src, vlan, bond->basis));
}
static struct bond_entry *
lookup_bond_entry(const struct bond *bond, const struct flow *flow,
uint16_t vlan)
{
return &bond->hash[bond_hash(bond, flow, vlan) & BOND_MASK];
}
/* This function uses Highest Random Weight hashing to choose an output slave.
* This approach only reassigns a minimal number of flows when slaves are
* enabled or disabled. Unfortunately, it has O(n) performance against the
* number of slaves. There exist algorithms which are O(1), but have slightly
* more complex implementations and require the use of memory. This may need
* to be reimplemented if it becomes a performance bottleneck. */
static struct bond_slave *
choose_stb_slave(const struct bond *bond, uint32_t flow_hash)
{
struct bond_slave *best, *slave;
uint32_t best_hash;
best = NULL;
best_hash = 0;
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (slave->enabled) {
uint32_t hash;
hash = hash_2words(flow_hash, slave->stb_id);
if (!best || hash > best_hash) {
best = slave;
best_hash = hash;
}
}
}
return best;
}
static struct bond_slave *
choose_output_slave(const struct bond *bond, const struct flow *flow,
uint16_t vlan)
{
struct bond_entry *e;
if (bond->lacp_status == LACP_CONFIGURED) {
/* LACP has been configured on this bond but negotiations were
* unsuccussful. Drop all traffic. */
return NULL;
}
switch (bond->balance) {
case BM_AB:
return bond->active_slave;
case BM_STABLE:
return choose_stb_slave(bond, bond_hash_tcp(flow, vlan, bond->basis));
case BM_TCP:
if (bond->lacp_status != LACP_NEGOTIATED) {
/* Must have LACP negotiations for TCP balanced bonds. */
return NULL;
}
/* Fall Through. */
case BM_SLB:
if (!bond_is_balanced(bond)) {
return choose_stb_slave(bond, bond_hash(bond, flow, vlan));
}
e = lookup_bond_entry(bond, flow, vlan);
if (!e->slave || !e->slave->enabled) {
e->slave = CONTAINER_OF(hmap_random_node(&bond->slaves),
struct bond_slave, hmap_node);
if (!e->slave->enabled) {
e->slave = bond->active_slave;
}
e->tag = tag_create_random();
}
return e->slave;
default:
NOT_REACHED();
}
}
static struct bond_slave *
bond_choose_slave(const struct bond *bond)
{
struct bond_slave *slave, *best;
/* Find an enabled slave. */
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (slave->enabled) {
return slave;
}
}
/* All interfaces are disabled. Find an interface that will be enabled
* after its updelay expires. */
best = NULL;
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
if (slave->delay_expires != LLONG_MAX
&& slave->may_enable
&& (!best || slave->delay_expires < best->delay_expires)) {
best = slave;
}
}
return best;
}
static void
bond_choose_active_slave(struct bond *bond, struct tag_set *tags)
{
static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
struct bond_slave *old_active_slave = bond->active_slave;
bond->active_slave = bond_choose_slave(bond);
if (bond->active_slave) {
if (bond->active_slave->enabled) {
VLOG_INFO_RL(&rl, "bond %s: active interface is now %s",
bond->name, bond->active_slave->name);
} else {
VLOG_INFO_RL(&rl, "bond %s: active interface is now %s, skipping "
"remaining %lld ms updelay (since no interface was "
"enabled)", bond->name, bond->active_slave->name,
bond->active_slave->delay_expires - time_msec());
bond_enable_slave(bond->active_slave, true, tags);
}
if (!old_active_slave) {
tag_set_add(tags, bond->no_slaves_tag);
}
bond->send_learning_packets = true;
} else if (old_active_slave) {
VLOG_WARN_RL(&rl, "bond %s: all interfaces disabled", bond->name);
}
}
/* Returns the tag for 'bond''s active slave, or 'bond''s no_slaves_tag if
* there is no active slave. */
static tag_type
bond_get_active_slave_tag(const struct bond *bond)
{
return (bond->active_slave
? bond->active_slave->tag
: bond->no_slaves_tag);
}
/* Attempts to make the sum of the bond slaves' statistics appear on the fake
* bond interface. */
static void
bond_update_fake_slave_stats(struct bond *bond)
{
struct netdev_stats bond_stats;
struct bond_slave *slave;
struct netdev *bond_dev;
memset(&bond_stats, 0, sizeof bond_stats);
HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
struct netdev_stats slave_stats;
if (!netdev_get_stats(slave->netdev, &slave_stats)) {
/* XXX: We swap the stats here because they are swapped back when
* reported by the internal device. The reason for this is
* internal devices normally represent packets going into the
* system but when used as fake bond device they represent packets
* leaving the system. We really should do this in the internal
* device itself because changing it here reverses the counts from
* the perspective of the switch. However, the internal device
* doesn't know what type of device it represents so we have to do
* it here for now. */
bond_stats.tx_packets += slave_stats.rx_packets;
bond_stats.tx_bytes += slave_stats.rx_bytes;
bond_stats.rx_packets += slave_stats.tx_packets;
bond_stats.rx_bytes += slave_stats.tx_bytes;
}
}
if (!netdev_open(bond->name, "system", &bond_dev)) {
netdev_set_stats(bond_dev, &bond_stats);
netdev_close(bond_dev);
}
}
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