2 * Copyright (c) 2008, 2009, 2010, 2011 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
26 #include "dynamic-string.h"
35 #include "poll-loop.h"
42 VLOG_DEFINE_THIS_MODULE(bond);
44 /* Bit-mask for hashing a flow down to a bucket.
45 * There are (BOND_MASK + 1) buckets. */
46 #define BOND_MASK 0xff
48 /* A hash bucket for mapping a flow to a slave.
49 * "struct bond" has an array of (BOND_MASK + 1) of these. */
51 struct bond_slave *slave; /* Assigned slave, NULL if unassigned. */
52 uint64_t tx_bytes; /* Count of bytes recently transmitted. */
53 tag_type tag; /* Tag for entry<->slave association. */
54 struct list list_node; /* In bond_slave's 'entries' list. */
57 /* A bond slave, that is, one of the links comprising a bond. */
59 struct hmap_node hmap_node; /* In struct bond's slaves hmap. */
60 struct bond *bond; /* The bond that contains this slave. */
61 void *aux; /* Client-provided handle for this slave. */
63 struct netdev *netdev; /* Network device, owned by the client. */
64 unsigned int change_seq; /* Tracks changes in 'netdev'. */
65 char *name; /* Name (a copy of netdev_get_name(netdev)). */
68 long long delay_expires; /* Time after which 'enabled' may change. */
69 bool enabled; /* May be chosen for flows? */
70 bool may_enable; /* Client considers this slave bondable. */
71 tag_type tag; /* Tag associated with this slave. */
73 /* Rebalancing info. Used only by bond_rebalance(). */
74 struct list bal_node; /* In bond_rebalance()'s 'bals' list. */
75 struct list entries; /* 'struct bond_entry's assigned here. */
76 uint64_t tx_bytes; /* Sum across 'tx_bytes' of entries. */
78 /* BM_STABLE specific bonding info. */
79 uint32_t stb_id; /* ID used for 'stb_slaves' ordering. */
82 /* A bond, that is, a set of network devices grouped to improve performance or
85 struct hmap_node hmap_node; /* In 'all_bonds' hmap. */
86 char *name; /* Name provided by client. */
92 enum bond_mode balance; /* Balancing mode, one of BM_*. */
93 struct bond_slave *active_slave;
94 tag_type no_slaves_tag; /* Tag for flows when all slaves disabled. */
95 int updelay, downdelay; /* Delay before slave goes up/down, in ms. */
96 enum lacp_status lacp_status; /* Status of LACP negotiations. */
97 bool bond_revalidate; /* True if flows need revalidation. */
98 uint32_t basis; /* Basis for flow hash function. */
100 /* SLB specific bonding info. */
101 struct bond_entry *hash; /* An array of (BOND_MASK + 1) elements. */
102 int rebalance_interval; /* Interval between rebalances, in ms. */
103 long long int next_rebalance; /* Next rebalancing time. */
104 bool send_learning_packets;
106 /* BM_STABLE specific bonding info. */
107 tag_type stb_tag; /* Tag associated with this bond. */
109 /* Legacy compatibility. */
110 long long int next_fake_iface_update; /* LLONG_MAX if disabled. */
112 /* Tag set saved for next bond_run(). This tag set is a kluge for cases
113 * where we can't otherwise provide revalidation feedback to the client.
114 * That's only unixctl commands now; I hope no other cases will arise. */
115 struct tag_set unixctl_tags;
118 static struct hmap all_bonds = HMAP_INITIALIZER(&all_bonds);
120 static void bond_entry_reset(struct bond *);
121 static struct bond_slave *bond_slave_lookup(struct bond *, const void *slave_);
122 static void bond_enable_slave(struct bond_slave *, bool enable,
124 static void bond_link_status_update(struct bond_slave *, struct tag_set *);
125 static void bond_choose_active_slave(struct bond *, struct tag_set *);
126 static unsigned int bond_hash_src(const uint8_t mac[ETH_ADDR_LEN],
127 uint16_t vlan, uint32_t basis);
128 static unsigned int bond_hash_tcp(const struct flow *, uint16_t vlan,
130 static struct bond_entry *lookup_bond_entry(const struct bond *,
133 static tag_type bond_get_active_slave_tag(const struct bond *);
134 static struct bond_slave *choose_output_slave(const struct bond *,
137 static void bond_update_fake_slave_stats(struct bond *);
139 /* Attempts to parse 's' as the name of a bond balancing mode. If successful,
140 * stores the mode in '*balance' and returns true. Otherwise returns false
141 * without modifying '*balance'. */
143 bond_mode_from_string(enum bond_mode *balance, const char *s)
145 if (!strcmp(s, bond_mode_to_string(BM_TCP))) {
147 } else if (!strcmp(s, bond_mode_to_string(BM_SLB))) {
149 } else if (!strcmp(s, bond_mode_to_string(BM_STABLE))) {
150 *balance = BM_STABLE;
151 } else if (!strcmp(s, bond_mode_to_string(BM_AB))) {
159 /* Returns a string representing 'balance'. */
161 bond_mode_to_string(enum bond_mode balance) {
164 return "balance-tcp";
166 return "balance-slb";
170 return "active-backup";
176 /* Creates and returns a new bond whose configuration is initially taken from
179 * The caller should register each slave on the new bond by calling
180 * bond_slave_register(). */
182 bond_create(const struct bond_settings *s)
186 bond = xzalloc(sizeof *bond);
187 hmap_init(&bond->slaves);
188 bond->no_slaves_tag = tag_create_random();
189 bond->stb_tag = tag_create_random();
190 bond->next_fake_iface_update = LLONG_MAX;
192 bond_reconfigure(bond, s);
194 tag_set_init(&bond->unixctl_tags);
201 bond_destroy(struct bond *bond)
203 struct bond_slave *slave, *next_slave;
209 hmap_remove(&all_bonds, &bond->hmap_node);
211 HMAP_FOR_EACH_SAFE (slave, next_slave, hmap_node, &bond->slaves) {
212 hmap_remove(&bond->slaves, &slave->hmap_node);
213 /* Client owns 'slave->netdev'. */
217 hmap_destroy(&bond->slaves);
224 /* Updates 'bond''s overall configuration to 's'.
226 * The caller should register each slave on 'bond' by calling
227 * bond_slave_register(). This is optional if none of the slaves'
228 * configuration has changed. In any case it can't hurt.
230 * Returns true if the configuration has changed in such a way that requires
234 bond_reconfigure(struct bond *bond, const struct bond_settings *s)
236 bool revalidate = false;
238 if (!bond->name || strcmp(bond->name, s->name)) {
240 hmap_remove(&all_bonds, &bond->hmap_node);
243 bond->name = xstrdup(s->name);
244 hmap_insert(&all_bonds, &bond->hmap_node, hash_string(bond->name, 0));
247 bond->updelay = s->up_delay;
248 bond->downdelay = s->down_delay;
250 if (bond->rebalance_interval != s->rebalance_interval) {
251 bond->rebalance_interval = s->rebalance_interval;
255 if (bond->balance != s->balance) {
256 bond->balance = s->balance;
260 if (bond->basis != s->basis) {
261 bond->basis = s->basis;
266 if (bond->next_fake_iface_update == LLONG_MAX) {
267 bond->next_fake_iface_update = time_msec();
270 bond->next_fake_iface_update = LLONG_MAX;
273 if (bond->bond_revalidate) {
275 bond->bond_revalidate = false;
278 if (bond->balance == BM_AB || !bond->hash || revalidate) {
279 bond_entry_reset(bond);
286 bond_slave_set_netdev__(struct bond_slave *slave, struct netdev *netdev)
288 if (slave->netdev != netdev) {
289 slave->netdev = netdev;
290 slave->change_seq = 0;
294 /* Registers 'slave_' as a slave of 'bond'. The 'slave_' pointer is an
295 * arbitrary client-provided pointer that uniquely identifies a slave within a
296 * bond. If 'slave_' already exists within 'bond' then this function
297 * reconfigures the existing slave.
299 * 'stb_id' is used in BM_STABLE bonds to guarantee consistent slave choices
300 * across restarts and distributed vswitch instances. It should be unique per
301 * slave, and preferably consistent across restarts and reconfigurations.
303 * 'netdev' must be the network device that 'slave_' represents. It is owned
304 * by the client, so the client must not close it before either unregistering
305 * 'slave_' or destroying 'bond'.
308 bond_slave_register(struct bond *bond, void *slave_, uint32_t stb_id,
309 struct netdev *netdev)
311 struct bond_slave *slave = bond_slave_lookup(bond, slave_);
314 slave = xzalloc(sizeof *slave);
316 hmap_insert(&bond->slaves, &slave->hmap_node, hash_pointer(slave_, 0));
319 slave->delay_expires = LLONG_MAX;
320 slave->name = xstrdup(netdev_get_name(netdev));
321 bond->bond_revalidate = true;
323 slave->enabled = false;
324 bond_enable_slave(slave, netdev_get_carrier(netdev), NULL);
327 if (slave->stb_id != stb_id) {
328 slave->stb_id = stb_id;
329 bond->bond_revalidate = true;
332 bond_slave_set_netdev__(slave, netdev);
335 slave->name = xstrdup(netdev_get_name(netdev));
338 /* Updates the network device to be used with 'slave_' to 'netdev'.
340 * This is useful if the caller closes and re-opens the network device
341 * registered with bond_slave_register() but doesn't need to change anything
344 bond_slave_set_netdev(struct bond *bond, void *slave_, struct netdev *netdev)
346 struct bond_slave *slave = bond_slave_lookup(bond, slave_);
348 bond_slave_set_netdev__(slave, netdev);
352 /* Unregisters 'slave_' from 'bond'. If 'bond' does not contain such a slave
353 * then this function has no effect.
355 * Unregistering a slave invalidates all flows. */
357 bond_slave_unregister(struct bond *bond, const void *slave_)
359 struct bond_slave *slave = bond_slave_lookup(bond, slave_);
366 bond_enable_slave(slave, false, NULL);
368 del_active = bond->active_slave == slave;
370 struct bond_entry *e;
371 for (e = bond->hash; e <= &bond->hash[BOND_MASK]; e++) {
372 if (e->slave == slave) {
380 hmap_remove(&bond->slaves, &slave->hmap_node);
381 /* Client owns 'slave->netdev'. */
388 bond_choose_active_slave(bond, &tags);
389 bond->send_learning_packets = true;
393 /* Should be called on each slave in 'bond' before bond_run() to indicate
394 * whether or not 'slave_' may be enabled. This function is intended to allow
395 * other protocols to have some impact on bonding decisions. For example LACP
396 * or high level link monitoring protocols may decide that a given slave should
397 * not be able to send traffic. */
399 bond_slave_set_may_enable(struct bond *bond, void *slave_, bool may_enable)
401 bond_slave_lookup(bond, slave_)->may_enable = may_enable;
404 /* Performs periodic maintenance on 'bond'. The caller must provide 'tags' to
405 * allow tagged flows to be invalidated.
407 * The caller should check bond_should_send_learning_packets() afterward. */
409 bond_run(struct bond *bond, struct tag_set *tags, enum lacp_status lacp_status)
411 struct bond_slave *slave;
413 if (bond->lacp_status != lacp_status) {
414 bond->lacp_status = lacp_status;
415 bond->bond_revalidate = true;
418 /* Enable slaves based on link status and LACP feedback. */
419 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
420 bond_link_status_update(slave, tags);
421 slave->change_seq = netdev_change_seq(slave->netdev);
423 if (!bond->active_slave || !bond->active_slave->enabled) {
424 bond_choose_active_slave(bond, tags);
427 /* Update fake bond interface stats. */
428 if (time_msec() >= bond->next_fake_iface_update) {
429 bond_update_fake_slave_stats(bond);
430 bond->next_fake_iface_update = time_msec() + 1000;
433 if (bond->bond_revalidate) {
434 bond->bond_revalidate = false;
436 bond_entry_reset(bond);
437 if (bond->balance != BM_STABLE) {
438 struct bond_slave *slave;
440 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
441 tag_set_add(tags, slave->tag);
444 tag_set_add(tags, bond->stb_tag);
446 tag_set_add(tags, bond->no_slaves_tag);
449 /* Invalidate any tags required by */
450 tag_set_union(tags, &bond->unixctl_tags);
451 tag_set_init(&bond->unixctl_tags);
454 /* Causes poll_block() to wake up when 'bond' needs something to be done. */
456 bond_wait(struct bond *bond)
458 struct bond_slave *slave;
460 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
461 if (slave->delay_expires != LLONG_MAX) {
462 poll_timer_wait_until(slave->delay_expires);
465 if (slave->change_seq != netdev_change_seq(slave->netdev)) {
466 poll_immediate_wake();
470 if (bond->next_fake_iface_update != LLONG_MAX) {
471 poll_timer_wait_until(bond->next_fake_iface_update);
474 /* Ensure that any saved tags get revalidated right away. */
475 if (!tag_set_is_empty(&bond->unixctl_tags)) {
476 poll_immediate_wake();
479 /* We don't wait for bond->next_rebalance because rebalancing can only run
480 * at a flow account checkpoint. ofproto does checkpointing on its own
481 * schedule and bond_rebalance() gets called afterward, so we'd just be
482 * waking up for no purpose. */
485 /* MAC learning table interaction. */
488 may_send_learning_packets(const struct bond *bond)
490 return bond->lacp_status == LACP_DISABLED
491 && bond->balance != BM_AB
492 && bond->active_slave;
495 /* Returns true if 'bond' needs the client to send out packets to assist with
496 * MAC learning on 'bond'. If this function returns true, then the client
497 * should iterate through its MAC learning table for the bridge on which 'bond'
498 * is located. For each MAC that has been learned on a port other than 'bond',
499 * it should call bond_compose_learning_packet().
501 * This function will only return true if 'bond' is in SLB mode and LACP is not
502 * negotiated. Otherwise sending learning packets isn't necessary.
504 * Calling this function resets the state that it checks. */
506 bond_should_send_learning_packets(struct bond *bond)
508 bool send = bond->send_learning_packets && may_send_learning_packets(bond);
509 bond->send_learning_packets = false;
513 /* Sends a gratuitous learning packet on 'bond' from 'eth_src' on 'vlan'.
515 * See bond_should_send_learning_packets() for description of usage. The
516 * caller should send the composed packet on the port associated with
517 * port_aux and takes ownership of the returned ofpbuf. */
519 bond_compose_learning_packet(struct bond *bond,
520 const uint8_t eth_src[ETH_ADDR_LEN],
521 uint16_t vlan, void **port_aux)
523 struct bond_slave *slave;
524 struct ofpbuf *packet;
527 assert(may_send_learning_packets(bond));
529 memset(&flow, 0, sizeof flow);
530 memcpy(flow.dl_src, eth_src, ETH_ADDR_LEN);
531 slave = choose_output_slave(bond, &flow, vlan);
533 packet = ofpbuf_new(0);
534 compose_rarp(packet, eth_src);
536 eth_push_vlan(packet, htons(vlan));
539 *port_aux = slave->aux;
543 /* Checks whether a packet that arrived on 'slave_' within 'bond', with an
544 * Ethernet destination address of 'eth_dst', should be admitted.
546 * The return value is one of the following:
548 * - BV_ACCEPT: Admit the packet.
550 * - BV_DROP: Drop the packet.
552 * - BV_DROP_IF_MOVED: Consult the MAC learning table for the packet's
553 * Ethernet source address and VLAN. If there is none, or if the packet
554 * is on the learned port, then admit the packet. If a different port has
555 * been learned, however, drop the packet (and do not use it for MAC
559 bond_check_admissibility(struct bond *bond, const void *slave_,
560 const uint8_t eth_dst[ETH_ADDR_LEN], tag_type *tags)
562 struct bond_slave *slave = bond_slave_lookup(bond, slave_);
564 /* LACP bonds have very loose admissibility restrictions because we can
565 * assume the remote switch is aware of the bond and will "do the right
566 * thing". However, as a precaution we drop packets on disabled slaves
567 * because no correctly implemented partner switch should be sending
570 * If LACP is configured, but LACP negotiations have been unsuccessful, we
571 * drop all incoming traffic. */
572 switch (bond->lacp_status) {
573 case LACP_NEGOTIATED: return slave->enabled ? BV_ACCEPT : BV_DROP;
574 case LACP_CONFIGURED: return BV_DROP;
575 case LACP_DISABLED: break;
578 /* Drop all multicast packets on inactive slaves. */
579 if (eth_addr_is_multicast(eth_dst)) {
580 *tags |= bond_get_active_slave_tag(bond);
581 if (bond->active_slave != bond_slave_lookup(bond, slave_)) {
586 switch (bond->balance) {
588 /* Drop all packets which arrive on backup slaves. This is similar to
589 * how Linux bonding handles active-backup bonds. */
590 *tags |= bond_get_active_slave_tag(bond);
591 if (bond->active_slave != slave) {
592 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5);
594 VLOG_DBG_RL(&rl, "active-backup bond received packet on backup"
595 " slave (%s) destined for " ETH_ADDR_FMT,
596 slave->name, ETH_ADDR_ARGS(eth_dst));
602 /* TCP balanced bonds require successful LACP negotiated. Based on the
603 * above check, LACP is off on this bond. Therfore, we drop all
604 * incoming traffic. */
608 /* Drop all packets for which we have learned a different input port,
609 * because we probably sent the packet on one slave and got it back on
610 * the other. Gratuitous ARP packets are an exception to this rule:
611 * the host has moved to another switch. The exception to the
612 * exception is if we locked the learning table to avoid reflections on
614 return BV_DROP_IF_MOVED;
623 /* Returns the slave (registered on 'bond' by bond_slave_register()) to which
624 * a packet with the given 'flow' and 'vlan' should be forwarded. Returns
625 * NULL if the packet should be dropped because no slaves are enabled.
627 * 'vlan' is not necessarily the same as 'flow->vlan_tci'. First, 'vlan'
628 * should be a VID only (i.e. excluding the PCP bits). Second,
629 * 'flow->vlan_tci' is the VLAN TCI that appeared on the packet (so it will be
630 * nonzero only for trunk ports), whereas 'vlan' is the logical VLAN that the
631 * packet belongs to (so for an access port it will be the access port's VLAN).
633 * Adds a tag to '*tags' that associates the flow with the returned slave.
636 bond_choose_output_slave(struct bond *bond, const struct flow *flow,
637 uint16_t vlan, tag_type *tags)
639 struct bond_slave *slave = choose_output_slave(bond, flow, vlan);
641 *tags |= bond->balance == BM_STABLE ? bond->stb_tag : slave->tag;
644 *tags |= bond->no_slaves_tag;
652 bond_is_balanced(const struct bond *bond)
654 return bond->rebalance_interval
655 && (bond->balance == BM_SLB || bond->balance == BM_TCP);
658 /* Notifies 'bond' that 'n_bytes' bytes were sent in 'flow' within 'vlan'. */
660 bond_account(struct bond *bond, const struct flow *flow, uint16_t vlan,
663 if (bond_is_balanced(bond)) {
664 lookup_bond_entry(bond, flow, vlan)->tx_bytes += n_bytes;
668 static struct bond_slave *
669 bond_slave_from_bal_node(struct list *bal)
671 return CONTAINER_OF(bal, struct bond_slave, bal_node);
675 log_bals(struct bond *bond, const struct list *bals)
677 if (VLOG_IS_DBG_ENABLED()) {
678 struct ds ds = DS_EMPTY_INITIALIZER;
679 const struct bond_slave *slave;
681 LIST_FOR_EACH (slave, bal_node, bals) {
683 ds_put_char(&ds, ',');
685 ds_put_format(&ds, " %s %"PRIu64"kB",
686 slave->name, slave->tx_bytes / 1024);
688 if (!slave->enabled) {
689 ds_put_cstr(&ds, " (disabled)");
691 if (!list_is_empty(&slave->entries)) {
692 struct bond_entry *e;
694 ds_put_cstr(&ds, " (");
695 LIST_FOR_EACH (e, list_node, &slave->entries) {
696 if (&e->list_node != list_front(&slave->entries)) {
697 ds_put_cstr(&ds, " + ");
699 ds_put_format(&ds, "h%td: %"PRIu64"kB",
700 e - bond->hash, e->tx_bytes / 1024);
702 ds_put_cstr(&ds, ")");
705 VLOG_DBG("bond %s:%s", bond->name, ds_cstr(&ds));
710 /* Shifts 'hash' from its current slave to 'to'. */
712 bond_shift_load(struct bond_entry *hash, struct bond_slave *to,
715 struct bond_slave *from = hash->slave;
716 struct bond *bond = from->bond;
717 uint64_t delta = hash->tx_bytes;
719 VLOG_INFO("bond %s: shift %"PRIu64"kB of load (with hash %td) "
720 "from %s to %s (now carrying %"PRIu64"kB and "
721 "%"PRIu64"kB load, respectively)",
722 bond->name, delta / 1024, hash - bond->hash,
723 from->name, to->name,
724 (from->tx_bytes - delta) / 1024,
725 (to->tx_bytes + delta) / 1024);
727 /* Shift load away from 'from' to 'to'. */
728 from->tx_bytes -= delta;
729 to->tx_bytes += delta;
731 /* Arrange for flows to be revalidated. */
732 tag_set_add(set, hash->tag);
734 hash->tag = tag_create_random();
737 /* Pick and returns a bond_entry to migrate to 'to' (the least-loaded slave),
738 * given that doing so must decrease the ratio of the load on the two slaves by
739 * at least 0.1. Returns NULL if there is no appropriate entry.
741 * The list of entries isn't sorted. I don't know of a reason to prefer to
742 * shift away small hashes or large hashes. */
743 static struct bond_entry *
744 choose_entry_to_migrate(const struct bond_slave *from, uint64_t to_tx_bytes)
746 struct bond_entry *e;
748 if (list_is_short(&from->entries)) {
749 /* 'from' carries no more than one MAC hash, so shifting load away from
750 * it would be pointless. */
754 LIST_FOR_EACH (e, list_node, &from->entries) {
755 double old_ratio, new_ratio;
758 if (to_tx_bytes == 0) {
759 /* Nothing on the new slave, move it. */
764 old_ratio = (double)from->tx_bytes / to_tx_bytes;
765 new_ratio = (double)(from->tx_bytes - delta) / (to_tx_bytes + delta);
766 if (old_ratio - new_ratio > 0.1) {
767 /* Would decrease the ratio, move it. */
775 /* Inserts 'slave' into 'bals' so that descending order of 'tx_bytes' is
778 insert_bal(struct list *bals, struct bond_slave *slave)
780 struct bond_slave *pos;
782 LIST_FOR_EACH (pos, bal_node, bals) {
783 if (slave->tx_bytes > pos->tx_bytes) {
787 list_insert(&pos->bal_node, &slave->bal_node);
790 /* Removes 'slave' from its current list and then inserts it into 'bals' so
791 * that descending order of 'tx_bytes' is maintained. */
793 reinsert_bal(struct list *bals, struct bond_slave *slave)
795 list_remove(&slave->bal_node);
796 insert_bal(bals, slave);
799 /* If 'bond' needs rebalancing, does so.
801 * The caller should have called bond_account() for each active flow, to ensure
802 * that flow data is consistently accounted at this point. */
804 bond_rebalance(struct bond *bond, struct tag_set *tags)
806 struct bond_slave *slave;
807 struct bond_entry *e;
810 if (!bond_is_balanced(bond) || time_msec() < bond->next_rebalance) {
813 bond->next_rebalance = time_msec() + bond->rebalance_interval;
815 /* Add each bond_entry to its slave's 'entries' list.
816 * Compute each slave's tx_bytes as the sum of its entries' tx_bytes. */
817 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
819 list_init(&slave->entries);
821 for (e = &bond->hash[0]; e <= &bond->hash[BOND_MASK]; e++) {
822 if (e->slave && e->tx_bytes) {
823 e->slave->tx_bytes += e->tx_bytes;
824 list_push_back(&e->slave->entries, &e->list_node);
828 /* Add enabled slaves to 'bals' in descending order of tx_bytes.
830 * XXX This is O(n**2) in the number of slaves but it could be O(n lg n)
831 * with a proper list sort algorithm. */
833 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
834 if (slave->enabled) {
835 insert_bal(&bals, slave);
838 log_bals(bond, &bals);
840 /* Shift load from the most-loaded slaves to the least-loaded slaves. */
841 while (!list_is_short(&bals)) {
842 struct bond_slave *from = bond_slave_from_bal_node(list_front(&bals));
843 struct bond_slave *to = bond_slave_from_bal_node(list_back(&bals));
846 overload = from->tx_bytes - to->tx_bytes;
847 if (overload < to->tx_bytes >> 5 || overload < 100000) {
848 /* The extra load on 'from' (and all less-loaded slaves), compared
849 * to that of 'to' (the least-loaded slave), is less than ~3%, or
850 * it is less than ~1Mbps. No point in rebalancing. */
854 /* 'from' is carrying significantly more load than 'to', and that load
855 * is split across at least two different hashes. */
856 e = choose_entry_to_migrate(from, to->tx_bytes);
858 bond_shift_load(e, to, tags);
860 /* Delete element from from->entries.
862 * We don't add the element to to->hashes. That would only allow
863 * 'e' to be migrated to another slave in this rebalancing run, and
864 * there is no point in doing that. */
865 list_remove(&e->list_node);
867 /* Re-sort 'bals'. */
868 reinsert_bal(&bals, from);
869 reinsert_bal(&bals, to);
871 /* Can't usefully migrate anything away from 'from'.
872 * Don't reconsider it. */
873 list_remove(&from->bal_node);
877 /* Implement exponentially weighted moving average. A weight of 1/2 causes
878 * historical data to decay to <1% in 7 rebalancing runs. 1,000,000 bytes
879 * take 20 rebalancing runs to decay to 0 and get deleted entirely. */
880 for (e = &bond->hash[0]; e <= &bond->hash[BOND_MASK]; e++) {
888 /* Bonding unixctl user interface functions. */
891 bond_find(const char *name)
895 HMAP_FOR_EACH_WITH_HASH (bond, hmap_node, hash_string(name, 0),
897 if (!strcmp(bond->name, name)) {
904 static struct bond_slave *
905 bond_lookup_slave(struct bond *bond, const char *slave_name)
907 struct bond_slave *slave;
909 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
910 if (!strcmp(slave->name, slave_name)) {
918 bond_unixctl_list(struct unixctl_conn *conn,
919 int argc OVS_UNUSED, const char *argv[] OVS_UNUSED,
920 void *aux OVS_UNUSED)
922 struct ds ds = DS_EMPTY_INITIALIZER;
923 const struct bond *bond;
925 ds_put_cstr(&ds, "bond\ttype\tslaves\n");
927 HMAP_FOR_EACH (bond, hmap_node, &all_bonds) {
928 const struct bond_slave *slave;
931 ds_put_format(&ds, "%s\t%s\t",
932 bond->name, bond_mode_to_string(bond->balance));
935 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
937 ds_put_cstr(&ds, ", ");
939 ds_put_cstr(&ds, slave->name);
941 ds_put_char(&ds, '\n');
943 unixctl_command_reply(conn, ds_cstr(&ds));
948 bond_print_details(struct ds *ds, const struct bond *bond)
950 struct shash slave_shash = SHASH_INITIALIZER(&slave_shash);
951 const struct shash_node **sorted_slaves = NULL;
952 const struct bond_slave *slave;
955 ds_put_format(ds, "---- %s ----\n", bond->name);
956 ds_put_format(ds, "bond_mode: %s\n",
957 bond_mode_to_string(bond->balance));
959 ds_put_format(ds, "bond-hash-basis: %"PRIu32"\n", bond->basis);
961 ds_put_format(ds, "updelay: %d ms\n", bond->updelay);
962 ds_put_format(ds, "downdelay: %d ms\n", bond->downdelay);
964 if (bond_is_balanced(bond)) {
965 ds_put_format(ds, "next rebalance: %lld ms\n",
966 bond->next_rebalance - time_msec());
969 ds_put_cstr(ds, "lacp_status: ");
970 switch (bond->lacp_status) {
971 case LACP_NEGOTIATED:
972 ds_put_cstr(ds, "negotiated\n");
974 case LACP_CONFIGURED:
975 ds_put_cstr(ds, "configured\n");
978 ds_put_cstr(ds, "off\n");
981 ds_put_cstr(ds, "<unknown>\n");
985 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
986 shash_add(&slave_shash, slave->name, slave);
988 sorted_slaves = shash_sort(&slave_shash);
990 for (i = 0; i < shash_count(&slave_shash); i++) {
991 struct bond_entry *be;
993 slave = sorted_slaves[i]->data;
996 ds_put_format(ds, "\nslave %s: %s\n",
997 slave->name, slave->enabled ? "enabled" : "disabled");
998 if (slave == bond->active_slave) {
999 ds_put_cstr(ds, "\tactive slave\n");
1001 if (slave->delay_expires != LLONG_MAX) {
1002 ds_put_format(ds, "\t%s expires in %lld ms\n",
1003 slave->enabled ? "downdelay" : "updelay",
1004 slave->delay_expires - time_msec());
1007 ds_put_format(ds, "\tmay_enable: %s\n",
1008 slave->may_enable ? "true" : "false");
1010 if (!bond_is_balanced(bond)) {
1015 for (be = bond->hash; be <= &bond->hash[BOND_MASK]; be++) {
1016 int hash = be - bond->hash;
1018 if (be->slave != slave) {
1022 ds_put_format(ds, "\thash %d: %"PRIu64" kB load\n",
1023 hash, be->tx_bytes / 1024);
1025 /* XXX How can we list the MACs assigned to hashes of SLB bonds? */
1028 shash_destroy(&slave_shash);
1029 free(sorted_slaves);
1030 ds_put_cstr(ds, "\n");
1034 bond_unixctl_show(struct unixctl_conn *conn,
1035 int argc, const char *argv[],
1036 void *aux OVS_UNUSED)
1038 struct ds ds = DS_EMPTY_INITIALIZER;
1041 const struct bond *bond = bond_find(argv[1]);
1044 unixctl_command_reply_error(conn, "no such bond");
1047 bond_print_details(&ds, bond);
1049 const struct bond *bond;
1051 HMAP_FOR_EACH (bond, hmap_node, &all_bonds) {
1052 bond_print_details(&ds, bond);
1056 unixctl_command_reply(conn, ds_cstr(&ds));
1061 bond_unixctl_migrate(struct unixctl_conn *conn,
1062 int argc OVS_UNUSED, const char *argv[],
1063 void *aux OVS_UNUSED)
1065 const char *bond_s = argv[1];
1066 const char *hash_s = argv[2];
1067 const char *slave_s = argv[3];
1069 struct bond_slave *slave;
1070 struct bond_entry *entry;
1073 bond = bond_find(bond_s);
1075 unixctl_command_reply_error(conn, "no such bond");
1079 if (bond->balance != BM_SLB) {
1080 unixctl_command_reply_error(conn, "not an SLB bond");
1084 if (strspn(hash_s, "0123456789") == strlen(hash_s)) {
1085 hash = atoi(hash_s) & BOND_MASK;
1087 unixctl_command_reply_error(conn, "bad hash");
1091 slave = bond_lookup_slave(bond, slave_s);
1093 unixctl_command_reply_error(conn, "no such slave");
1097 if (!slave->enabled) {
1098 unixctl_command_reply_error(conn, "cannot migrate to disabled slave");
1102 entry = &bond->hash[hash];
1103 tag_set_add(&bond->unixctl_tags, entry->tag);
1104 entry->slave = slave;
1105 entry->tag = tag_create_random();
1106 unixctl_command_reply(conn, "migrated");
1110 bond_unixctl_set_active_slave(struct unixctl_conn *conn,
1111 int argc OVS_UNUSED, const char *argv[],
1112 void *aux OVS_UNUSED)
1114 const char *bond_s = argv[1];
1115 const char *slave_s = argv[2];
1117 struct bond_slave *slave;
1119 bond = bond_find(bond_s);
1121 unixctl_command_reply_error(conn, "no such bond");
1125 slave = bond_lookup_slave(bond, slave_s);
1127 unixctl_command_reply_error(conn, "no such slave");
1131 if (!slave->enabled) {
1132 unixctl_command_reply_error(conn, "cannot make disabled slave active");
1136 if (bond->active_slave != slave) {
1137 tag_set_add(&bond->unixctl_tags, bond_get_active_slave_tag(bond));
1138 bond->active_slave = slave;
1139 bond->active_slave->tag = tag_create_random();
1140 VLOG_INFO("bond %s: active interface is now %s",
1141 bond->name, slave->name);
1142 bond->send_learning_packets = true;
1143 unixctl_command_reply(conn, "done");
1145 unixctl_command_reply(conn, "no change");
1150 enable_slave(struct unixctl_conn *conn, const char *argv[], bool enable)
1152 const char *bond_s = argv[1];
1153 const char *slave_s = argv[2];
1155 struct bond_slave *slave;
1157 bond = bond_find(bond_s);
1159 unixctl_command_reply_error(conn, "no such bond");
1163 slave = bond_lookup_slave(bond, slave_s);
1165 unixctl_command_reply_error(conn, "no such slave");
1169 bond_enable_slave(slave, enable, &bond->unixctl_tags);
1170 unixctl_command_reply(conn, enable ? "enabled" : "disabled");
1174 bond_unixctl_enable_slave(struct unixctl_conn *conn,
1175 int argc OVS_UNUSED, const char *argv[],
1176 void *aux OVS_UNUSED)
1178 enable_slave(conn, argv, true);
1182 bond_unixctl_disable_slave(struct unixctl_conn *conn,
1183 int argc OVS_UNUSED, const char *argv[],
1184 void *aux OVS_UNUSED)
1186 enable_slave(conn, argv, false);
1190 bond_unixctl_hash(struct unixctl_conn *conn, int argc, const char *argv[],
1191 void *aux OVS_UNUSED)
1193 const char *mac_s = argv[1];
1194 const char *vlan_s = argc > 2 ? argv[2] : NULL;
1195 const char *basis_s = argc > 3 ? argv[3] : NULL;
1196 uint8_t mac[ETH_ADDR_LEN];
1203 if (sscanf(vlan_s, "%u", &vlan) != 1) {
1204 unixctl_command_reply_error(conn, "invalid vlan");
1212 if (sscanf(basis_s, "%"PRIu32, &basis) != 1) {
1213 unixctl_command_reply_error(conn, "invalid basis");
1220 if (sscanf(mac_s, ETH_ADDR_SCAN_FMT, ETH_ADDR_SCAN_ARGS(mac))
1221 == ETH_ADDR_SCAN_COUNT) {
1222 hash = bond_hash_src(mac, vlan, basis) & BOND_MASK;
1224 hash_cstr = xasprintf("%u", hash);
1225 unixctl_command_reply(conn, hash_cstr);
1228 unixctl_command_reply_error(conn, "invalid mac");
1235 unixctl_command_register("bond/list", "", 0, 0, bond_unixctl_list, NULL);
1236 unixctl_command_register("bond/show", "[port]", 0, 1, bond_unixctl_show,
1238 unixctl_command_register("bond/migrate", "port hash slave", 3, 3,
1239 bond_unixctl_migrate, NULL);
1240 unixctl_command_register("bond/set-active-slave", "port slave", 2, 2,
1241 bond_unixctl_set_active_slave, NULL);
1242 unixctl_command_register("bond/enable-slave", "port slave", 2, 2,
1243 bond_unixctl_enable_slave, NULL);
1244 unixctl_command_register("bond/disable-slave", "port slave", 2, 2,
1245 bond_unixctl_disable_slave, NULL);
1246 unixctl_command_register("bond/hash", "mac [vlan] [basis]", 1, 3,
1247 bond_unixctl_hash, NULL);
1251 bond_entry_reset(struct bond *bond)
1253 if (bond->balance != BM_AB) {
1254 size_t hash_len = (BOND_MASK + 1) * sizeof *bond->hash;
1257 bond->hash = xmalloc(hash_len);
1259 memset(bond->hash, 0, hash_len);
1261 bond->next_rebalance = time_msec() + bond->rebalance_interval;
1268 static struct bond_slave *
1269 bond_slave_lookup(struct bond *bond, const void *slave_)
1271 struct bond_slave *slave;
1273 HMAP_FOR_EACH_IN_BUCKET (slave, hmap_node, hash_pointer(slave_, 0),
1275 if (slave->aux == slave_) {
1284 bond_enable_slave(struct bond_slave *slave, bool enable, struct tag_set *tags)
1286 struct bond *bond = slave->bond;
1287 slave->delay_expires = LLONG_MAX;
1288 if (enable != slave->enabled) {
1289 slave->enabled = enable;
1290 if (!slave->enabled) {
1291 VLOG_WARN("interface %s: disabled", slave->name);
1293 tag_set_add(tags, slave->tag);
1296 VLOG_WARN("interface %s: enabled", slave->name);
1297 slave->tag = tag_create_random();
1300 if (bond->balance == BM_STABLE) {
1301 bond->bond_revalidate = true;
1307 bond_link_status_update(struct bond_slave *slave, struct tag_set *tags)
1309 struct bond *bond = slave->bond;
1312 up = netdev_get_carrier(slave->netdev) && slave->may_enable;
1313 if ((up == slave->enabled) != (slave->delay_expires == LLONG_MAX)) {
1314 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
1315 VLOG_INFO_RL(&rl, "interface %s: link state %s",
1316 slave->name, up ? "up" : "down");
1317 if (up == slave->enabled) {
1318 slave->delay_expires = LLONG_MAX;
1319 VLOG_INFO_RL(&rl, "interface %s: will not be %s",
1320 slave->name, up ? "disabled" : "enabled");
1322 int delay = (bond->lacp_status != LACP_DISABLED ? 0
1323 : up ? bond->updelay : bond->downdelay);
1324 slave->delay_expires = time_msec() + delay;
1326 VLOG_INFO_RL(&rl, "interface %s: will be %s if it stays %s "
1329 up ? "enabled" : "disabled",
1336 if (time_msec() >= slave->delay_expires) {
1337 bond_enable_slave(slave, up, tags);
1342 bond_hash_src(const uint8_t mac[ETH_ADDR_LEN], uint16_t vlan, uint32_t basis)
1344 return hash_3words(hash_bytes(mac, ETH_ADDR_LEN, 0), vlan, basis);
1348 bond_hash_tcp(const struct flow *flow, uint16_t vlan, uint32_t basis)
1350 struct flow hash_flow = *flow;
1351 hash_flow.vlan_tci = htons(vlan);
1353 /* The symmetric quality of this hash function is not required, but
1354 * flow_hash_symmetric_l4 already exists, and is sufficient for our
1355 * purposes, so we use it out of convenience. */
1356 return flow_hash_symmetric_l4(&hash_flow, basis);
1360 bond_hash(const struct bond *bond, const struct flow *flow, uint16_t vlan)
1362 assert(bond->balance == BM_TCP || bond->balance == BM_SLB);
1364 return (bond->balance == BM_TCP
1365 ? bond_hash_tcp(flow, vlan, bond->basis)
1366 : bond_hash_src(flow->dl_src, vlan, bond->basis));
1369 static struct bond_entry *
1370 lookup_bond_entry(const struct bond *bond, const struct flow *flow,
1373 return &bond->hash[bond_hash(bond, flow, vlan) & BOND_MASK];
1376 /* This function uses Highest Random Weight hashing to choose an output slave.
1377 * This approach only reassigns a minimal number of flows when slaves are
1378 * enabled or disabled. Unfortunately, it has O(n) performance against the
1379 * number of slaves. There exist algorithms which are O(1), but have slightly
1380 * more complex implementations and require the use of memory. This may need
1381 * to be reimplemented if it becomes a performance bottleneck. */
1382 static struct bond_slave *
1383 choose_stb_slave(const struct bond *bond, uint32_t flow_hash)
1385 struct bond_slave *best, *slave;
1390 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
1391 if (slave->enabled) {
1394 hash = hash_2words(flow_hash, slave->stb_id);
1395 if (!best || hash > best_hash) {
1405 static struct bond_slave *
1406 choose_output_slave(const struct bond *bond, const struct flow *flow,
1409 struct bond_entry *e;
1411 if (bond->lacp_status == LACP_CONFIGURED) {
1412 /* LACP has been configured on this bond but negotiations were
1413 * unsuccussful. Drop all traffic. */
1417 switch (bond->balance) {
1419 return bond->active_slave;
1422 return choose_stb_slave(bond, bond_hash_tcp(flow, vlan, bond->basis));
1425 if (bond->lacp_status != LACP_NEGOTIATED) {
1426 /* Must have LACP negotiations for TCP balanced bonds. */
1431 if (!bond_is_balanced(bond)) {
1432 return choose_stb_slave(bond, bond_hash(bond, flow, vlan));
1434 e = lookup_bond_entry(bond, flow, vlan);
1435 if (!e->slave || !e->slave->enabled) {
1436 e->slave = CONTAINER_OF(hmap_random_node(&bond->slaves),
1437 struct bond_slave, hmap_node);
1438 if (!e->slave->enabled) {
1439 e->slave = bond->active_slave;
1441 e->tag = tag_create_random();
1450 static struct bond_slave *
1451 bond_choose_slave(const struct bond *bond)
1453 struct bond_slave *slave, *best;
1455 /* Find an enabled slave. */
1456 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
1457 if (slave->enabled) {
1462 /* All interfaces are disabled. Find an interface that will be enabled
1463 * after its updelay expires. */
1465 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
1466 if (slave->delay_expires != LLONG_MAX
1467 && slave->may_enable
1468 && (!best || slave->delay_expires < best->delay_expires)) {
1476 bond_choose_active_slave(struct bond *bond, struct tag_set *tags)
1478 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
1479 struct bond_slave *old_active_slave = bond->active_slave;
1481 bond->active_slave = bond_choose_slave(bond);
1482 if (bond->active_slave) {
1483 if (bond->active_slave->enabled) {
1484 VLOG_INFO_RL(&rl, "bond %s: active interface is now %s",
1485 bond->name, bond->active_slave->name);
1487 VLOG_INFO_RL(&rl, "bond %s: active interface is now %s, skipping "
1488 "remaining %lld ms updelay (since no interface was "
1489 "enabled)", bond->name, bond->active_slave->name,
1490 bond->active_slave->delay_expires - time_msec());
1491 bond_enable_slave(bond->active_slave, true, tags);
1494 if (!old_active_slave) {
1495 tag_set_add(tags, bond->no_slaves_tag);
1498 bond->send_learning_packets = true;
1499 } else if (old_active_slave) {
1500 VLOG_WARN_RL(&rl, "bond %s: all interfaces disabled", bond->name);
1504 /* Returns the tag for 'bond''s active slave, or 'bond''s no_slaves_tag if
1505 * there is no active slave. */
1507 bond_get_active_slave_tag(const struct bond *bond)
1509 return (bond->active_slave
1510 ? bond->active_slave->tag
1511 : bond->no_slaves_tag);
1514 /* Attempts to make the sum of the bond slaves' statistics appear on the fake
1515 * bond interface. */
1517 bond_update_fake_slave_stats(struct bond *bond)
1519 struct netdev_stats bond_stats;
1520 struct bond_slave *slave;
1521 struct netdev *bond_dev;
1523 memset(&bond_stats, 0, sizeof bond_stats);
1525 HMAP_FOR_EACH (slave, hmap_node, &bond->slaves) {
1526 struct netdev_stats slave_stats;
1528 if (!netdev_get_stats(slave->netdev, &slave_stats)) {
1529 /* XXX: We swap the stats here because they are swapped back when
1530 * reported by the internal device. The reason for this is
1531 * internal devices normally represent packets going into the
1532 * system but when used as fake bond device they represent packets
1533 * leaving the system. We really should do this in the internal
1534 * device itself because changing it here reverses the counts from
1535 * the perspective of the switch. However, the internal device
1536 * doesn't know what type of device it represents so we have to do
1537 * it here for now. */
1538 bond_stats.tx_packets += slave_stats.rx_packets;
1539 bond_stats.tx_bytes += slave_stats.rx_bytes;
1540 bond_stats.rx_packets += slave_stats.tx_packets;
1541 bond_stats.rx_bytes += slave_stats.tx_bytes;
1545 if (!netdev_open(bond->name, "system", &bond_dev)) {
1546 netdev_set_stats(bond_dev, &bond_stats);
1547 netdev_close(bond_dev);