lib/lacp.c

   1 /* Copyright (c) 2011 Nicira Networks
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at:
   6  *
   7  *     http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12  * See the License for the specific language governing permissions and
  13  * limitations under the License.
  14  */
  15
  16 #include <config.h>
  17 #include "lacp.h"
  18
  19 #include <assert.h>
  20 #include <stdlib.h>
  21
  22 #include "dynamic-string.h"
  23 #include "hash.h"
  24 #include "hmap.h"
  25 #include "ofpbuf.h"
  26 #include "packets.h"
  27 #include "poll-loop.h"
  28 #include "timer.h"
  29 #include "timeval.h"
  30 #include "unixctl.h"
  31 #include "vlog.h"
  32
  33 VLOG_DEFINE_THIS_MODULE(lacp);
  34
  35 enum slave_status {
  36     LACP_CURRENT,   /* Current State.  Partner up to date. */
  37     LACP_EXPIRED,   /* Expired State.  Partner out of date. */
  38     LACP_DEFAULTED, /* Defaulted State.  No partner. */
  39 };
  40
  41 struct lacp {
  42     struct list node;             /* Node in all_lacps list. */
  43     char *name;                   /* Name of this lacp object. */
  44     uint8_t sys_id[ETH_ADDR_LEN]; /* System ID. */
  45     uint16_t sys_priority;        /* System Priority. */
  46     bool active;                  /* Active or Passive. */
  47
  48     struct hmap slaves;      /* Slaves this LACP object controls. */
  49     struct slave *key_slave; /* Slave whose ID will be the aggregation key. */
  50
  51     bool fast;                /* Fast or Slow LACP time. */
  52     bool negotiated;         /* True if LACP negotiations were successful. */
  53     bool update;             /* True if lacp_update() needs to be called. */
  54 };
  55
  56 struct slave {
  57     void *aux;                    /* Handle used to identify this slave. */
  58     struct hmap_node node;        /* Node in master's slaves map. */
  59
  60     struct lacp *lacp;            /* LACP object containing this slave. */
  61     uint16_t port_id;             /* Port ID. */
  62     uint16_t port_priority;       /* Port Priority. */
  63     char *name;                   /* Name of this slave. */
  64
  65     enum slave_status status;     /* Slave status. */
  66     bool attached;                /* Attached. Traffic may flow. */
  67     struct lacp_info partner;     /* Partner information. */
  68     struct lacp_info ntt_actor;   /* Used to decide if we Need To Transmit. */
  69     struct timer tx;              /* Next message transmission timer. */
  70     struct timer rx;              /* Expected message receive timer. */
  71 };
  72
  73 static struct list all_lacps = LIST_INITIALIZER(&all_lacps);
  74
  75 static void lacp_update_attached(struct lacp *);
  76
  77 static void slave_destroy(struct slave *);
  78 static void slave_set_defaulted(struct slave *);
  79 static void slave_set_expired(struct slave *);
  80 static void slave_get_actor(struct slave *, struct lacp_info *actor);
  81 static void slave_get_priority(struct slave *, struct lacp_info *priority);
  82 static bool slave_may_tx(const struct slave *);
  83 static struct slave *slave_lookup(const struct lacp *, const void *slave);
  84 static bool info_tx_equal(struct lacp_info *, struct lacp_info *);
  85
  86 static void lacp_unixctl_show(struct unixctl_conn *, const char *args,
  87                               void *aux);
  88
  89 /* Initializes the lacp module. */
  90 void
  91 lacp_init(void)
  92 {
  93     unixctl_command_register("lacp/show", lacp_unixctl_show, NULL);
  94 }
  95
  96 /* Creates a LACP object. */
  97 struct lacp *
  98 lacp_create(void)
  99 {
 100     struct lacp *lacp;
 101
 102     lacp = xzalloc(sizeof *lacp);
 103     hmap_init(&lacp->slaves);
 104     list_push_back(&all_lacps, &lacp->node);
 105     return lacp;
 106 }
 107
 108 /* Destroys 'lacp' and its slaves. Does nothing if 'lacp' is NULL. */
 109 void
 110 lacp_destroy(struct lacp *lacp)
 111 {
 112     if (lacp) {
 113         struct slave *slave, *next;
 114
 115         HMAP_FOR_EACH_SAFE (slave, next, node, &lacp->slaves) {
 116             slave_destroy(slave);
 117         }
 118
 119         hmap_destroy(&lacp->slaves);
 120         list_remove(&lacp->node);
 121         free(lacp->name);
 122         free(lacp);
 123     }
 124 }
 125
 126 /* Configures 'lacp' with settings from 's'. */
 127 void
 128 lacp_configure(struct lacp *lacp, const struct lacp_settings *s)
 129 {
 130     if (!lacp->name || strcmp(s->name, lacp->name)) {
 131         free(lacp->name);
 132         lacp->name = xstrdup(s->name);
 133     }
 134
 135     memcpy(lacp->sys_id, s->id, ETH_ADDR_LEN);
 136     lacp->sys_priority = s->priority;
 137     lacp->active = s->active;
 138     lacp->fast = s->fast;
 139 }
 140
 141 /* Returns true if 'lacp' is configured in active mode, false if 'lacp' is
 142  * configured for passive mode. */
 143 bool
 144 lacp_is_active(const struct lacp *lacp)
 145 {
 146     return lacp->active;
 147 }
 148
 149 /* Processes 'pdu', a parsed LACP packet received on 'slave_'.  This function
 150  * should be called on all packets received on 'slave_' with Ethernet Type
 151  * ETH_TYPE_LACP and parsable by parse_lacp_packet(). */
 152 void
 153 lacp_process_pdu(struct lacp *lacp, const void *slave_,
 154                  const struct lacp_pdu *pdu)
 155 {
 156     struct slave *slave = slave_lookup(lacp, slave_);
 157
 158     slave->status = LACP_CURRENT;
 159     timer_set_duration(&slave->rx, (lacp->fast
 160                                     ? LACP_FAST_TIME_RX
 161                                     : LACP_SLOW_TIME_RX));
 162
 163     slave->ntt_actor = pdu->partner;
 164
 165     /* Update our information about our partner if it's out of date.  This may
 166      * cause priorities to change so re-calculate attached status of all
 167      * slaves.  */
 168     if (memcmp(&slave->partner, &pdu->actor, sizeof pdu->actor)) {
 169         lacp->update = true;
 170         slave->partner = pdu->actor;
 171     }
 172 }
 173
 174 /* Returns true if 'lacp' has successfully negotiated with its partner.  False
 175  * if 'lacp' is NULL. */
 176 bool
 177 lacp_negotiated(const struct lacp *lacp)
 178 {
 179     return lacp ? lacp->negotiated : false;
 180 }
 181
 182 /* Registers 'slave_' as subordinate to 'lacp'.  This should be called at least
 183  * once per slave in a LACP managed bond.  Should also be called whenever a
 184  * slave's settings change. */
 185 void
 186 lacp_slave_register(struct lacp *lacp, void *slave_,
 187                     const struct lacp_slave_settings *s)
 188 {
 189     struct slave *slave = slave_lookup(lacp, slave_);
 190
 191     if (!slave) {
 192         slave = xzalloc(sizeof *slave);
 193         slave->lacp = lacp;
 194         slave->aux = slave_;
 195         hmap_insert(&lacp->slaves, &slave->node, hash_pointer(slave_, 0));
 196         slave_set_defaulted(slave);
 197
 198         if (!lacp->key_slave) {
 199             lacp->key_slave = slave;
 200         }
 201     }
 202
 203     if (!slave->name || strcmp(s->name, slave->name)) {
 204         free(slave->name);
 205         slave->name = xstrdup(s->name);
 206     }
 207
 208     if (slave->port_id != s->id || slave->port_priority != s->priority) {
 209         slave->port_id = s->id;
 210         slave->port_priority = s->priority;
 211
 212         lacp->update = true;
 213
 214         if (lacp->active || lacp->negotiated) {
 215             slave_set_expired(slave);
 216         }
 217     }
 218 }
 219
 220 /* Unregisters 'slave_' with 'lacp'.  */
 221 void
 222 lacp_slave_unregister(struct lacp *lacp, const void *slave_)
 223 {
 224     struct slave *slave = slave_lookup(lacp, slave_);
 225
 226     if (slave) {
 227         slave_destroy(slave);
 228     }
 229 }
 230
 231 /* This function should be called whenever the carrier status of 'slave_' has
 232  * changed. */
 233 void
 234 lacp_slave_carrier_changed(const struct lacp *lacp, const void *slave_)
 235 {
 236     struct slave *slave = slave_lookup(lacp, slave_);
 237
 238     if (slave->status == LACP_CURRENT || slave->lacp->active) {
 239         slave_set_expired(slave);
 240     }
 241 }
 242
 243 /* This function should be called before enabling 'slave_' to send or receive
 244  * traffic.  If it returns false, 'slave_' should not enabled.  As a
 245  * convenience, returns true if 'lacp' is NULL. */
 246 bool
 247 lacp_slave_may_enable(const struct lacp *lacp, const void *slave_)
 248 {
 249     if (lacp) {
 250         struct slave *slave = slave_lookup(lacp, slave_);
 251
 252         /* The slave may be enabled if it's attached to an aggregator and its
 253          * partner is synchronized.  The only exception is defaulted slaves.
 254          * They are not required to have synchronized partners because they
 255          * have no partners at all.  They will only be attached if negotiations
 256          * failed on all slaves in the bond. */
 257         return slave->attached && (slave->partner.state & LACP_STATE_SYNC
 258                                    || slave->status == LACP_DEFAULTED);
 259     } else {
 260         return true;
 261     }
 262 }
 263
 264 /* Returns the port ID used for 'slave_' in LACP communications. */
 265 uint16_t
 266 lacp_slave_get_port_id(const struct lacp *lacp, const void *slave_)
 267 {
 268     struct slave *slave = slave_lookup(lacp, slave_);
 269     return slave->port_id;
 270 }
 271
 272 /* Returns true if partner information on 'slave_' is up to date.  'slave_'
 273  * not being current, generally indicates a connectivity problem, or a
 274  * misconfigured (or broken) partner. */
 275 bool
 276 lacp_slave_is_current(const struct lacp *lacp, const void *slave_)
 277 {
 278     return slave_lookup(lacp, slave_)->status == LACP_CURRENT;
 279 }
 280
 281 /* This function should be called periodically to update 'lacp'. */
 282 void
 283 lacp_run(struct lacp *lacp, lacp_send_pdu *send_pdu)
 284 {
 285     struct slave *slave;
 286
 287     HMAP_FOR_EACH (slave, node, &lacp->slaves) {
 288         if (timer_expired(&slave->rx)) {
 289             if (slave->status == LACP_CURRENT) {
 290                 slave_set_expired(slave);
 291             } else if (slave->status == LACP_EXPIRED) {
 292                 slave_set_defaulted(slave);
 293             }
 294         }
 295     }
 296
 297     if (lacp->update) {
 298         lacp_update_attached(lacp);
 299     }
 300
 301     HMAP_FOR_EACH (slave, node, &lacp->slaves) {
 302         struct lacp_pdu pdu;
 303         struct lacp_info actor;
 304
 305         if (!slave_may_tx(slave)) {
 306             continue;
 307         }
 308
 309         slave_get_actor(slave, &actor);
 310
 311         if (timer_expired(&slave->tx)
 312             || !info_tx_equal(&actor, &slave->ntt_actor)) {
 313
 314             slave->ntt_actor = actor;
 315             compose_lacp_pdu(&actor, &slave->partner, &pdu);
 316             send_pdu(slave->aux, &pdu);
 317
 318             timer_set_duration(&slave->tx,
 319                                (slave->partner.state & LACP_STATE_TIME
 320                                 ? LACP_FAST_TIME_TX
 321                                 : LACP_SLOW_TIME_TX));
 322         }
 323     }
 324 }
 325
 326 /* Causes poll_block() to wake up when lacp_run() needs to be called again. */
 327 void
 328 lacp_wait(struct lacp *lacp)
 329 {
 330     struct slave *slave;
 331
 332     HMAP_FOR_EACH (slave, node, &lacp->slaves) {
 333         if (slave_may_tx(slave)) {
 334             timer_wait(&slave->tx);
 335         }
 336
 337         if (slave->status != LACP_DEFAULTED) {
 338             timer_wait(&slave->rx);
 339         }
 340     }
 341 }
 342 \f
 343 /* Static Helpers. */
 344
 345 /* Updates the attached status of all slaves controlled b 'lacp' and sets its
 346  * negotiated parameter to true if any slaves are attachable. */
 347 static void
 348 lacp_update_attached(struct lacp *lacp)
 349 {
 350     struct slave *lead, *slave;
 351     struct lacp_info lead_pri;
 352     static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 10);
 353
 354     lacp->update = false;
 355
 356     lead = NULL;
 357     HMAP_FOR_EACH (slave, node, &lacp->slaves) {
 358         struct lacp_info pri;
 359
 360         slave->attached = true;
 361
 362         /* XXX: In the future allow users to configure the expected system ID.
 363          * For now just special case loopback. */
 364         if (eth_addr_equals(slave->partner.sys_id, slave->lacp->sys_id)) {
 365             VLOG_WARN_RL(&rl, "slave %s: Loopback detected. Slave is "
 366                          "connected to its own bond", slave->name);
 367             slave->attached = false;
 368             continue;
 369         }
 370
 371         if (slave->status == LACP_DEFAULTED) {
 372             continue;
 373         }
 374
 375         slave_get_priority(slave, &pri);
 376
 377         if (!lead || memcmp(&pri, &lead_pri, sizeof pri) < 0) {
 378             lead = slave;
 379             lead_pri = pri;
 380         }
 381     }
 382
 383     lacp->negotiated = lead != NULL;
 384
 385     if (lead) {
 386         HMAP_FOR_EACH (slave, node, &lacp->slaves) {
 387             if (slave->status == LACP_DEFAULTED
 388                 || lead->partner.key != slave->partner.key
 389                 || !eth_addr_equals(lead->partner.sys_id,
 390                                     slave->partner.sys_id)) {
 391                 slave->attached = false;
 392             }
 393         }
 394     }
 395 }
 396
 397 static void
 398 slave_destroy(struct slave *slave)
 399 {
 400     if (slave) {
 401         struct lacp *lacp = slave->lacp;
 402
 403         lacp->update = true;
 404         hmap_remove(&lacp->slaves, &slave->node);
 405
 406         if (lacp->key_slave == slave) {
 407             struct hmap_node *slave_node = hmap_first(&lacp->slaves);
 408
 409             if (slave_node) {
 410                 lacp->key_slave = CONTAINER_OF(slave_node, struct slave, node);
 411             } else {
 412                 lacp->key_slave = NULL;
 413             }
 414         }
 415
 416         free(slave->name);
 417         free(slave);
 418     }
 419 }
 420
 421 static void
 422 slave_set_defaulted(struct slave *slave)
 423 {
 424     memset(&slave->partner, 0, sizeof slave->partner);
 425
 426     slave->lacp->update = true;
 427     slave->status = LACP_DEFAULTED;
 428 }
 429
 430 static void
 431 slave_set_expired(struct slave *slave)
 432 {
 433     slave->status = LACP_EXPIRED;
 434     slave->partner.state |= LACP_STATE_TIME;
 435     slave->partner.state &= ~LACP_STATE_SYNC;
 436     timer_set_duration(&slave->rx, LACP_FAST_TIME_RX);
 437 }
 438
 439 static void
 440 slave_get_actor(struct slave *slave, struct lacp_info *actor)
 441 {
 442     uint8_t state = 0;
 443
 444     if (slave->lacp->active) {
 445         state |= LACP_STATE_ACT;
 446     }
 447
 448     if (slave->lacp->fast) {
 449         state |= LACP_STATE_TIME;
 450     }
 451
 452     if (slave->attached) {
 453         state |= LACP_STATE_SYNC;
 454     }
 455
 456     if (slave->status == LACP_DEFAULTED) {
 457         state |= LACP_STATE_DEF;
 458     }
 459
 460     if (slave->status == LACP_EXPIRED) {
 461         state |= LACP_STATE_EXP;
 462     }
 463
 464     if (hmap_count(&slave->lacp->slaves) > 1) {
 465         state |= LACP_STATE_AGG;
 466     }
 467
 468     if (slave->attached || !slave->lacp->negotiated) {
 469         state |= LACP_STATE_COL | LACP_STATE_DIST;
 470     }
 471
 472     actor->state = state;
 473     actor->key = htons(slave->lacp->key_slave->port_id);
 474     actor->port_priority = htons(slave->port_priority);
 475     actor->port_id = htons(slave->port_id);
 476     actor->sys_priority = htons(slave->lacp->sys_priority);
 477     memcpy(&actor->sys_id, slave->lacp->sys_id, ETH_ADDR_LEN);
 478 }
 479
 480 /* Given 'slave', populates 'priority' with data representing its LACP link
 481  * priority.  If two priority objects populated by this function are compared
 482  * using memcmp, the higher priority link will be less than the lower priority
 483  * link. */
 484 static void
 485 slave_get_priority(struct slave *slave, struct lacp_info *priority)
 486 {
 487     uint16_t partner_priority, actor_priority;
 488
 489     /* Choose the lacp_info of the higher priority system by comparing their
 490      * system priorities and mac addresses. */
 491     actor_priority = slave->lacp->sys_priority;
 492     partner_priority = ntohs(slave->partner.sys_priority);
 493     if (actor_priority < partner_priority) {
 494         slave_get_actor(slave, priority);
 495     } else if (partner_priority < actor_priority) {
 496         *priority = slave->partner;
 497     } else if (eth_addr_compare_3way(slave->lacp->sys_id,
 498                                      slave->partner.sys_id) < 0) {
 499         slave_get_actor(slave, priority);
 500     } else {
 501         *priority = slave->partner;
 502     }
 503
 504     /* Key and state are not used in priority comparisons. */
 505     priority->key = 0;
 506     priority->state = 0;
 507 }
 508
 509 static bool
 510 slave_may_tx(const struct slave *slave)
 511 {
 512     return slave->lacp->active || slave->status != LACP_DEFAULTED;
 513 }
 514
 515 static struct slave *
 516 slave_lookup(const struct lacp *lacp, const void *slave_)
 517 {
 518     struct slave *slave;
 519
 520     HMAP_FOR_EACH_IN_BUCKET (slave, node, hash_pointer(slave_, 0),
 521                              &lacp->slaves) {
 522         if (slave->aux == slave_) {
 523             return slave;
 524         }
 525     }
 526
 527     return NULL;
 528 }
 529
 530 /* Two lacp_info structures are tx_equal if and only if they do not differ in
 531  * ways which would require a lacp_pdu transmission. */
 532 static bool
 533 info_tx_equal(struct lacp_info *a, struct lacp_info *b)
 534 {
 535
 536     /* LACP specification dictates that we transmit whenever the actor and
 537      * remote_actor differ in the following fields: Port, Port Priority,
 538      * System, System Priority, Aggregation Key, Activity State, Timeout State,
 539      * Sync State, and Aggregation State. The state flags are most likely to
 540      * change so are checked first. */
 541     return !((a->state ^ b->state) & (LACP_STATE_ACT
 542                                       | LACP_STATE_TIME
 543                                       | LACP_STATE_SYNC
 544                                       | LACP_STATE_AGG))
 545         && a->port_id == b->port_id
 546         && a->port_priority == b->port_priority
 547         && a->key == b->key
 548         && a->sys_priority == b->sys_priority
 549         && eth_addr_equals(a->sys_id, b->sys_id);
 550 }
 551 \f
 552 static struct lacp *
 553 lacp_find(const char *name)
 554 {
 555     struct lacp *lacp;
 556
 557     LIST_FOR_EACH (lacp, node, &all_lacps) {
 558         if (!strcmp(lacp->name, name)) {
 559             return lacp;
 560         }
 561     }
 562
 563     return NULL;
 564 }
 565
 566 static void
 567 ds_put_lacp_state(struct ds *ds, uint8_t state)
 568 {
 569     if (state & LACP_STATE_ACT) {
 570         ds_put_cstr(ds, "activity ");
 571     }
 572
 573     if (state & LACP_STATE_TIME) {
 574         ds_put_cstr(ds, "timeout ");
 575     }
 576
 577     if (state & LACP_STATE_AGG) {
 578         ds_put_cstr(ds, "aggregation ");
 579     }
 580
 581     if (state & LACP_STATE_SYNC) {
 582         ds_put_cstr(ds, "synchronized ");
 583     }
 584
 585     if (state & LACP_STATE_COL) {
 586         ds_put_cstr(ds, "collecting ");
 587     }
 588
 589     if (state & LACP_STATE_DIST) {
 590         ds_put_cstr(ds, "distributing ");
 591     }
 592
 593     if (state & LACP_STATE_DEF) {
 594         ds_put_cstr(ds, "defaulted ");
 595     }
 596
 597     if (state & LACP_STATE_EXP) {
 598         ds_put_cstr(ds, "expired ");
 599     }
 600 }
 601
 602 static void
 603 lacp_unixctl_show(struct unixctl_conn *conn,
 604                   const char *args, void *aux OVS_UNUSED)
 605 {
 606     struct ds ds = DS_EMPTY_INITIALIZER;
 607     struct lacp *lacp;
 608     struct slave *slave;
 609
 610     lacp = lacp_find(args);
 611     if (!lacp) {
 612         unixctl_command_reply(conn, 501, "no such lacp object");
 613         return;
 614     }
 615
 616     ds_put_format(&ds, "lacp: %s\n", lacp->name);
 617     ds_put_format(&ds, "\tstatus: %s %s\n",
 618                   lacp->active ? "active" : "passive",
 619                   lacp->negotiated ? "negotiated" : "");
 620     ds_put_format(&ds, "\tsys_id: " ETH_ADDR_FMT "\n", ETH_ADDR_ARGS(lacp->sys_id));
 621     ds_put_format(&ds, "\tsys_priority: %u\n", lacp->sys_priority);
 622     ds_put_cstr(&ds, "\taggregation key: ");
 623     if (lacp->key_slave) {
 624         ds_put_format(&ds, "%u", lacp->key_slave->port_id);
 625     } else {
 626         ds_put_cstr(&ds, "none");
 627     }
 628     ds_put_cstr(&ds, "\n");
 629
 630     HMAP_FOR_EACH (slave, node, &lacp->slaves) {
 631         char *status;
 632         struct lacp_info actor;
 633
 634         slave_get_actor(slave, &actor);
 635         switch (slave->status) {
 636         case LACP_CURRENT:
 637             status = "current";
 638             break;
 639         case LACP_EXPIRED:
 640             status = "expired";
 641             break;
 642         case LACP_DEFAULTED:
 643             status = "defaulted";
 644             break;
 645         default:
 646             NOT_REACHED();
 647         }
 648
 649         ds_put_format(&ds, "\nslave: %s: %s %s\n", slave->name, status,
 650                       slave->attached ? "attached" : "detached");
 651         ds_put_format(&ds, "\tport_id: %u\n", slave->port_id);
 652         ds_put_format(&ds, "\tport_priority: %u\n", slave->port_priority);
 653
 654         ds_put_format(&ds, "\n\tactor sys_id: " ETH_ADDR_FMT "\n",
 655                       ETH_ADDR_ARGS(actor.sys_id));
 656         ds_put_format(&ds, "\tactor sys_priority: %u\n",
 657                       ntohs(actor.sys_priority));
 658         ds_put_format(&ds, "\tactor port_id: %u\n",
 659                       ntohs(actor.port_id));
 660         ds_put_format(&ds, "\tactor port_priority: %u\n",
 661                       ntohs(actor.port_priority));
 662         ds_put_format(&ds, "\tactor key: %u\n",
 663                       ntohs(actor.key));
 664         ds_put_cstr(&ds, "\tactor state: ");
 665         ds_put_lacp_state(&ds, actor.state);
 666         ds_put_cstr(&ds, "\n\n");
 667
 668         ds_put_format(&ds, "\tpartner sys_id: " ETH_ADDR_FMT "\n",
 669                       ETH_ADDR_ARGS(slave->partner.sys_id));
 670         ds_put_format(&ds, "\tpartner sys_priority: %u\n",
 671                       ntohs(slave->partner.sys_priority));
 672         ds_put_format(&ds, "\tpartner port_id: %u\n",
 673                       ntohs(slave->partner.port_id));
 674         ds_put_format(&ds, "\tpartner port_priority: %u\n",
 675                       ntohs(slave->partner.port_priority));
 676         ds_put_format(&ds, "\tpartner key: %u\n",
 677                       ntohs(slave->partner.key));
 678         ds_put_cstr(&ds, "\tpartner state: ");
 679         ds_put_lacp_state(&ds, slave->partner.state);
 680         ds_put_cstr(&ds, "\n");
 681     }
 682
 683     unixctl_command_reply(conn, 200, ds_cstr(&ds));
 684     ds_destroy(&ds);
 685 }