lib/learning-switch.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
   3  *
   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:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  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.
  15  */
  16
  17 #include <config.h>
  18 #include "learning-switch.h"
  19
  20 #include <errno.h>
  21 #include <inttypes.h>
  22 #include <netinet/in.h>
  23 #include <stdlib.h>
  24 #include <time.h>
  25
  26 #include "byte-order.h"
  27 #include "classifier.h"
  28 #include "flow.h"
  29 #include "hmap.h"
  30 #include "mac-learning.h"
  31 #include "ofpbuf.h"
  32 #include "ofp-actions.h"
  33 #include "ofp-errors.h"
  34 #include "ofp-msgs.h"
  35 #include "ofp-parse.h"
  36 #include "ofp-print.h"
  37 #include "ofp-util.h"
  38 #include "openflow/openflow.h"
  39 #include "poll-loop.h"
  40 #include "rconn.h"
  41 #include "shash.h"
  42 #include "simap.h"
  43 #include "timeval.h"
  44 #include "vconn.h"
  45 #include "vlog.h"
  46
  47 VLOG_DEFINE_THIS_MODULE(learning_switch);
  48
  49 struct lswitch_port {
  50     struct hmap_node hmap_node; /* Hash node for port number. */
  51     uint16_t port_no;           /* OpenFlow port number, in host byte order. */
  52     uint32_t queue_id;          /* OpenFlow queue number. */
  53 };
  54
  55 enum lswitch_state {
  56     S_CONNECTING,               /* Waiting for connection to complete. */
  57     S_FEATURES_REPLY,           /* Waiting for features reply. */
  58     S_SWITCHING,                /* Switching flows. */
  59 };
  60
  61 struct lswitch {
  62     struct rconn *rconn;
  63     enum lswitch_state state;
  64
  65     /* If nonnegative, the switch sets up flows that expire after the given
  66      * number of seconds (or never expire, if the value is OFP_FLOW_PERMANENT).
  67      * Otherwise, the switch processes every packet. */
  68     int max_idle;
  69
  70     enum ofputil_protocol protocol;
  71     unsigned long long int datapath_id;
  72     struct mac_learning *ml;    /* NULL to act as hub instead of switch. */
  73     struct flow_wildcards wc;   /* Wildcards to apply to flows. */
  74     bool action_normal;         /* Use OFPP_NORMAL? */
  75
  76     /* Queue distribution. */
  77     uint32_t default_queue;     /* Default OpenFlow queue, or UINT32_MAX. */
  78     struct hmap queue_numbers;  /* Map from port number to lswitch_port. */
  79     struct shash queue_names;   /* Map from port name to lswitch_port. */
  80
  81     /* Number of outgoing queued packets on the rconn. */
  82     struct rconn_packet_counter *queued;
  83
  84     /* If true, do not reply to any messages from the switch (for debugging
  85      * fail-open mode). */
  86     bool mute;
  87
  88     /* Optional "flow mod" requests to send to the switch at connection time,
  89      * to set up the flow table. */
  90     const struct ofputil_flow_mod *default_flows;
  91     size_t n_default_flows;
  92 };
  93
  94 /* The log messages here could actually be useful in debugging, so keep the
  95  * rate limit relatively high. */
  96 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(30, 300);
  97
  98 static void queue_tx(struct lswitch *, struct ofpbuf *);
  99 static void send_features_request(struct lswitch *);
 100
 101 static void lswitch_process_packet(struct lswitch *, const struct ofpbuf *);
 102 static enum ofperr process_switch_features(struct lswitch *,
 103                                            struct ofp_header *);
 104 static void process_packet_in(struct lswitch *, const struct ofp_header *);
 105 static void process_echo_request(struct lswitch *, const struct ofp_header *);
 106
 107 /* Creates and returns a new learning switch whose configuration is given by
 108  * 'cfg'.
 109  *
 110  * 'rconn' is used to send out an OpenFlow features request. */
 111 struct lswitch *
 112 lswitch_create(struct rconn *rconn, const struct lswitch_config *cfg)
 113 {
 114     struct lswitch *sw;
 115     uint32_t ofpfw;
 116
 117     sw = xzalloc(sizeof *sw);
 118     sw->rconn = rconn;
 119     sw->state = S_CONNECTING;
 120     sw->max_idle = cfg->max_idle;
 121     sw->datapath_id = 0;
 122     sw->ml = (cfg->mode == LSW_LEARN
 123               ? mac_learning_create(MAC_ENTRY_DEFAULT_IDLE_TIME)
 124               : NULL);
 125     sw->action_normal = cfg->mode == LSW_NORMAL;
 126
 127     switch (cfg->wildcards) {
 128     case 0:
 129         ofpfw = 0;
 130         break;
 131
 132     case UINT32_MAX:
 133         /* Try to wildcard as many fields as possible, but we cannot
 134          * wildcard all fields.  We need in_port to detect moves.  We need
 135          * Ethernet source and dest and VLAN VID to do L2 learning. */
 136         ofpfw = (OFPFW10_DL_TYPE | OFPFW10_DL_VLAN_PCP
 137                  | OFPFW10_NW_SRC_ALL | OFPFW10_NW_DST_ALL
 138                  | OFPFW10_NW_TOS | OFPFW10_NW_PROTO
 139                  | OFPFW10_TP_SRC | OFPFW10_TP_DST);
 140         break;
 141
 142     default:
 143         ofpfw = cfg->wildcards;
 144         break;
 145     }
 146     ofputil_wildcard_from_ofpfw10(ofpfw, &sw->wc);
 147
 148     sw->default_queue = cfg->default_queue;
 149     hmap_init(&sw->queue_numbers);
 150     shash_init(&sw->queue_names);
 151     if (cfg->port_queues) {
 152         struct simap_node *node;
 153
 154         SIMAP_FOR_EACH (node, cfg->port_queues) {
 155             struct lswitch_port *port = xmalloc(sizeof *port);
 156             hmap_node_nullify(&port->hmap_node);
 157             port->queue_id = node->data;
 158             shash_add(&sw->queue_names, node->name, port);
 159         }
 160     }
 161
 162     sw->default_flows = cfg->default_flows;
 163     sw->n_default_flows = cfg->n_default_flows;
 164
 165     sw->queued = rconn_packet_counter_create();
 166
 167     return sw;
 168 }
 169
 170 static void
 171 lswitch_handshake(struct lswitch *sw)
 172 {
 173     enum ofputil_protocol protocol;
 174
 175     send_features_request(sw);
 176
 177     protocol = ofputil_protocol_from_ofp_version(rconn_get_version(sw->rconn));
 178     if (sw->default_flows) {
 179         enum ofputil_protocol usable_protocols;
 180         struct ofpbuf *msg = NULL;
 181         int error = 0;
 182         size_t i;
 183
 184         /* If the initial protocol isn't good enough for default_flows, then
 185          * pick one that will work and encode messages to set up that
 186          * protocol.
 187          *
 188          * This could be improved by actually negotiating a mutually acceptable
 189          * flow format with the switch, but that would require an asynchronous
 190          * state machine.  This version ought to work fine in practice. */
 191         usable_protocols = ofputil_flow_mod_usable_protocols(
 192             sw->default_flows, sw->n_default_flows);
 193         if (!(protocol & usable_protocols)) {
 194             enum ofputil_protocol want = rightmost_1bit(usable_protocols);
 195             while (!error) {
 196                 msg = ofputil_encode_set_protocol(protocol, want, &protocol);
 197                 if (!msg) {
 198                     break;
 199                 }
 200                 error = rconn_send(sw->rconn, msg, NULL);
 201             }
 202         }
 203
 204         for (i = 0; !error && i < sw->n_default_flows; i++) {
 205             msg = ofputil_encode_flow_mod(&sw->default_flows[i], protocol);
 206             error = rconn_send(sw->rconn, msg, NULL);
 207         }
 208
 209         if (error) {
 210             VLOG_INFO_RL(&rl, "%s: failed to queue default flows (%s)",
 211                          rconn_get_name(sw->rconn), strerror(error));
 212         }
 213     }
 214     sw->protocol = protocol;
 215 }
 216
 217 bool
 218 lswitch_is_alive(const struct lswitch *sw)
 219 {
 220     return rconn_is_alive(sw->rconn);
 221 }
 222
 223 /* Destroys 'sw'. */
 224 void
 225 lswitch_destroy(struct lswitch *sw)
 226 {
 227     if (sw) {
 228         struct lswitch_port *node, *next;
 229
 230         rconn_destroy(sw->rconn);
 231         HMAP_FOR_EACH_SAFE (node, next, hmap_node, &sw->queue_numbers) {
 232             hmap_remove(&sw->queue_numbers, &node->hmap_node);
 233             free(node);
 234         }
 235         shash_destroy(&sw->queue_names);
 236         mac_learning_destroy(sw->ml);
 237         rconn_packet_counter_destroy(sw->queued);
 238         free(sw);
 239     }
 240 }
 241
 242 /* Takes care of necessary 'sw' activity, except for receiving packets (which
 243  * the caller must do). */
 244 void
 245 lswitch_run(struct lswitch *sw)
 246 {
 247     int i;
 248
 249     if (sw->ml) {
 250         mac_learning_run(sw->ml, NULL);
 251     }
 252
 253     rconn_run(sw->rconn);
 254
 255     if (sw->state == S_CONNECTING) {
 256         if (rconn_get_version(sw->rconn) != -1) {
 257             lswitch_handshake(sw);
 258             sw->state = S_FEATURES_REPLY;
 259         }
 260         return;
 261     }
 262
 263     for (i = 0; i < 50; i++) {
 264         struct ofpbuf *msg;
 265
 266         msg = rconn_recv(sw->rconn);
 267         if (!msg) {
 268             break;
 269         }
 270
 271         if (!sw->mute) {
 272             lswitch_process_packet(sw, msg);
 273         }
 274         ofpbuf_delete(msg);
 275     }
 276 }
 277
 278 void
 279 lswitch_wait(struct lswitch *sw)
 280 {
 281     if (sw->ml) {
 282         mac_learning_wait(sw->ml);
 283     }
 284     rconn_run_wait(sw->rconn);
 285     rconn_recv_wait(sw->rconn);
 286 }
 287
 288 /* Processes 'msg', which should be an OpenFlow received on 'rconn', according
 289  * to the learning switch state in 'sw'.  The most likely result of processing
 290  * is that flow-setup and packet-out OpenFlow messages will be sent out on
 291  * 'rconn'.  */
 292 static void
 293 lswitch_process_packet(struct lswitch *sw, const struct ofpbuf *msg)
 294 {
 295     enum ofptype type;
 296     struct ofpbuf b;
 297
 298     b = *msg;
 299     if (ofptype_pull(&type, &b)) {
 300         return;
 301     }
 302
 303     if (sw->state == S_FEATURES_REPLY
 304         && type != OFPTYPE_ECHO_REQUEST
 305         && type != OFPTYPE_FEATURES_REPLY) {
 306         return;
 307     }
 308
 309     switch (type) {
 310     case OFPTYPE_ECHO_REQUEST:
 311         process_echo_request(sw, msg->data);
 312         break;
 313
 314     case OFPTYPE_FEATURES_REPLY:
 315         if (sw->state == S_FEATURES_REPLY) {
 316             if (!process_switch_features(sw, msg->data)) {
 317                 sw->state = S_SWITCHING;
 318             } else {
 319                 rconn_disconnect(sw->rconn);
 320             }
 321         }
 322         break;
 323
 324     case OFPTYPE_PACKET_IN:
 325         process_packet_in(sw, msg->data);
 326         break;
 327
 328     case OFPTYPE_FLOW_REMOVED:
 329         /* Nothing to do. */
 330         break;
 331
 332     case OFPTYPE_HELLO:
 333     case OFPTYPE_ERROR:
 334     case OFPTYPE_ECHO_REPLY:
 335     case OFPTYPE_FEATURES_REQUEST:
 336     case OFPTYPE_GET_CONFIG_REQUEST:
 337     case OFPTYPE_GET_CONFIG_REPLY:
 338     case OFPTYPE_SET_CONFIG:
 339     case OFPTYPE_PORT_STATUS:
 340     case OFPTYPE_PACKET_OUT:
 341     case OFPTYPE_FLOW_MOD:
 342     case OFPTYPE_PORT_MOD:
 343     case OFPTYPE_BARRIER_REQUEST:
 344     case OFPTYPE_BARRIER_REPLY:
 345     case OFPTYPE_DESC_STATS_REQUEST:
 346     case OFPTYPE_DESC_STATS_REPLY:
 347     case OFPTYPE_FLOW_STATS_REQUEST:
 348     case OFPTYPE_FLOW_STATS_REPLY:
 349     case OFPTYPE_AGGREGATE_STATS_REQUEST:
 350     case OFPTYPE_AGGREGATE_STATS_REPLY:
 351     case OFPTYPE_TABLE_STATS_REQUEST:
 352     case OFPTYPE_TABLE_STATS_REPLY:
 353     case OFPTYPE_PORT_STATS_REQUEST:
 354     case OFPTYPE_PORT_STATS_REPLY:
 355     case OFPTYPE_QUEUE_STATS_REQUEST:
 356     case OFPTYPE_QUEUE_STATS_REPLY:
 357     case OFPTYPE_PORT_DESC_STATS_REQUEST:
 358     case OFPTYPE_PORT_DESC_STATS_REPLY:
 359     case OFPTYPE_ROLE_REQUEST:
 360     case OFPTYPE_ROLE_REPLY:
 361     case OFPTYPE_SET_FLOW_FORMAT:
 362     case OFPTYPE_FLOW_MOD_TABLE_ID:
 363     case OFPTYPE_SET_PACKET_IN_FORMAT:
 364     case OFPTYPE_FLOW_AGE:
 365     case OFPTYPE_SET_ASYNC_CONFIG:
 366     case OFPTYPE_SET_CONTROLLER_ID:
 367     case OFPTYPE_FLOW_MONITOR_STATS_REQUEST:
 368     case OFPTYPE_FLOW_MONITOR_STATS_REPLY:
 369     case OFPTYPE_FLOW_MONITOR_CANCEL:
 370     case OFPTYPE_FLOW_MONITOR_PAUSED:
 371     case OFPTYPE_FLOW_MONITOR_RESUMED:
 372     default:
 373         if (VLOG_IS_DBG_ENABLED()) {
 374             char *s = ofp_to_string(msg->data, msg->size, 2);
 375             VLOG_DBG_RL(&rl, "%016llx: OpenFlow packet ignored: %s",
 376                         sw->datapath_id, s);
 377             free(s);
 378         }
 379     }
 380 }
 381 \f
 382 static void
 383 send_features_request(struct lswitch *sw)
 384 {
 385     struct ofpbuf *b;
 386     struct ofp_switch_config *osc;
 387     int ofp_version = rconn_get_version(sw->rconn);
 388
 389     assert(ofp_version > 0 && ofp_version < 0xff);
 390
 391     /* Send OFPT_FEATURES_REQUEST. */
 392     b = ofpraw_alloc(OFPRAW_OFPT_FEATURES_REQUEST, ofp_version, 0);
 393     queue_tx(sw, b);
 394
 395     /* Send OFPT_SET_CONFIG. */
 396     b = ofpraw_alloc(OFPRAW_OFPT_SET_CONFIG, ofp_version, sizeof *osc);
 397     osc = ofpbuf_put_zeros(b, sizeof *osc);
 398     osc->miss_send_len = htons(OFP_DEFAULT_MISS_SEND_LEN);
 399     queue_tx(sw, b);
 400 }
 401
 402 static void
 403 queue_tx(struct lswitch *sw, struct ofpbuf *b)
 404 {
 405     int retval = rconn_send_with_limit(sw->rconn, b, sw->queued, 10);
 406     if (retval && retval != ENOTCONN) {
 407         if (retval == EAGAIN) {
 408             VLOG_INFO_RL(&rl, "%016llx: %s: tx queue overflow",
 409                          sw->datapath_id, rconn_get_name(sw->rconn));
 410         } else {
 411             VLOG_WARN_RL(&rl, "%016llx: %s: send: %s",
 412                          sw->datapath_id, rconn_get_name(sw->rconn),
 413                          strerror(retval));
 414         }
 415     }
 416 }
 417
 418 static enum ofperr
 419 process_switch_features(struct lswitch *sw, struct ofp_header *oh)
 420 {
 421     struct ofputil_switch_features features;
 422     struct ofputil_phy_port port;
 423     enum ofperr error;
 424     struct ofpbuf b;
 425
 426     error = ofputil_decode_switch_features(oh, &features, &b);
 427     if (error) {
 428         VLOG_ERR("received invalid switch feature reply (%s)",
 429                  ofperr_to_string(error));
 430         return error;
 431     }
 432
 433     sw->datapath_id = features.datapath_id;
 434
 435     while (!ofputil_pull_phy_port(oh->version, &b, &port)) {
 436         struct lswitch_port *lp = shash_find_data(&sw->queue_names, port.name);
 437         if (lp && hmap_node_is_null(&lp->hmap_node)) {
 438             lp->port_no = port.port_no;
 439             hmap_insert(&sw->queue_numbers, &lp->hmap_node,
 440                         hash_int(lp->port_no, 0));
 441         }
 442     }
 443     return 0;
 444 }
 445
 446 static uint16_t
 447 lswitch_choose_destination(struct lswitch *sw, const struct flow *flow)
 448 {
 449     uint16_t out_port;
 450
 451     /* Learn the source MAC. */
 452     if (mac_learning_may_learn(sw->ml, flow->dl_src, 0)) {
 453         struct mac_entry *mac = mac_learning_insert(sw->ml, flow->dl_src, 0);
 454         if (mac_entry_is_new(mac) || mac->port.i != flow->in_port) {
 455             VLOG_DBG_RL(&rl, "%016llx: learned that "ETH_ADDR_FMT" is on "
 456                         "port %"PRIu16, sw->datapath_id,
 457                         ETH_ADDR_ARGS(flow->dl_src), flow->in_port);
 458
 459             mac->port.i = flow->in_port;
 460             mac_learning_changed(sw->ml, mac);
 461         }
 462     }
 463
 464     /* Drop frames for reserved multicast addresses. */
 465     if (eth_addr_is_reserved(flow->dl_dst)) {
 466         return OFPP_NONE;
 467     }
 468
 469     out_port = OFPP_FLOOD;
 470     if (sw->ml) {
 471         struct mac_entry *mac;
 472
 473         mac = mac_learning_lookup(sw->ml, flow->dl_dst, 0, NULL);
 474         if (mac) {
 475             out_port = mac->port.i;
 476             if (out_port == flow->in_port) {
 477                 /* Don't send a packet back out its input port. */
 478                 return OFPP_NONE;
 479             }
 480         }
 481     }
 482
 483     /* Check if we need to use "NORMAL" action. */
 484     if (sw->action_normal && out_port != OFPP_FLOOD) {
 485         return OFPP_NORMAL;
 486     }
 487
 488     return out_port;
 489 }
 490
 491 static uint32_t
 492 get_queue_id(const struct lswitch *sw, uint16_t in_port)
 493 {
 494     const struct lswitch_port *port;
 495
 496     HMAP_FOR_EACH_WITH_HASH (port, hmap_node, hash_int(in_port, 0),
 497                              &sw->queue_numbers) {
 498         if (port->port_no == in_port) {
 499             return port->queue_id;
 500         }
 501     }
 502
 503     return sw->default_queue;
 504 }
 505
 506 static void
 507 process_packet_in(struct lswitch *sw, const struct ofp_header *oh)
 508 {
 509     struct ofputil_packet_in pi;
 510     uint32_t queue_id;
 511     uint16_t out_port;
 512
 513     uint64_t ofpacts_stub[64 / 8];
 514     struct ofpbuf ofpacts;
 515
 516     struct ofputil_packet_out po;
 517     enum ofperr error;
 518
 519     struct ofpbuf pkt;
 520     struct flow flow;
 521
 522     error = ofputil_decode_packet_in(&pi, oh);
 523     if (error) {
 524         VLOG_WARN_RL(&rl, "failed to decode packet-in: %s",
 525                      ofperr_to_string(error));
 526         return;
 527     }
 528
 529     /* Ignore packets sent via output to OFPP_CONTROLLER.  This library never
 530      * uses such an action.  You never know what experiments might be going on,
 531      * though, and it seems best not to interfere with them. */
 532     if (pi.reason != OFPR_NO_MATCH) {
 533         return;
 534     }
 535
 536     /* Extract flow data from 'opi' into 'flow'. */
 537     ofpbuf_use_const(&pkt, pi.packet, pi.packet_len);
 538     flow_extract(&pkt, 0, NULL, pi.fmd.in_port, &flow);
 539     flow.tunnel.tun_id = pi.fmd.tun_id;
 540
 541     /* Choose output port. */
 542     out_port = lswitch_choose_destination(sw, &flow);
 543
 544     /* Make actions. */
 545     queue_id = get_queue_id(sw, pi.fmd.in_port);
 546     ofpbuf_use_stack(&ofpacts, ofpacts_stub, sizeof ofpacts_stub);
 547     if (out_port == OFPP_NONE) {
 548         /* No actions. */
 549     } else if (queue_id == UINT32_MAX || out_port >= OFPP_MAX) {
 550         ofpact_put_OUTPUT(&ofpacts)->port = out_port;
 551     } else {
 552         struct ofpact_enqueue *enqueue = ofpact_put_ENQUEUE(&ofpacts);
 553         enqueue->port = out_port;
 554         enqueue->queue = queue_id;
 555     }
 556     ofpact_pad(&ofpacts);
 557
 558     /* Prepare packet_out in case we need one. */
 559     po.buffer_id = pi.buffer_id;
 560     if (po.buffer_id == UINT32_MAX) {
 561         po.packet = pkt.data;
 562         po.packet_len = pkt.size;
 563     } else {
 564         po.packet = NULL;
 565         po.packet_len = 0;
 566     }
 567     po.in_port = pi.fmd.in_port;
 568     po.ofpacts = ofpacts.data;
 569     po.ofpacts_len = ofpacts.size;
 570
 571     /* Send the packet, and possibly the whole flow, to the output port. */
 572     if (sw->max_idle >= 0 && (!sw->ml || out_port != OFPP_FLOOD)) {
 573         struct ofputil_flow_mod fm;
 574         struct ofpbuf *buffer;
 575
 576         /* The output port is known, or we always flood everything, so add a
 577          * new flow. */
 578         memset(&fm, 0, sizeof fm);
 579         match_init(&fm.match, &flow, &sw->wc);
 580         ofputil_normalize_match_quiet(&fm.match);
 581         fm.priority = 0;
 582         fm.table_id = 0xff;
 583         fm.command = OFPFC_ADD;
 584         fm.idle_timeout = sw->max_idle;
 585         fm.buffer_id = pi.buffer_id;
 586         fm.out_port = OFPP_NONE;
 587         fm.ofpacts = ofpacts.data;
 588         fm.ofpacts_len = ofpacts.size;
 589         buffer = ofputil_encode_flow_mod(&fm, sw->protocol);
 590
 591         queue_tx(sw, buffer);
 592
 593         /* If the switch didn't buffer the packet, we need to send a copy. */
 594         if (pi.buffer_id == UINT32_MAX && out_port != OFPP_NONE) {
 595             queue_tx(sw, ofputil_encode_packet_out(&po, sw->protocol));
 596         }
 597     } else {
 598         /* We don't know that MAC, or we don't set up flows.  Send along the
 599          * packet without setting up a flow. */
 600         if (pi.buffer_id != UINT32_MAX || out_port != OFPP_NONE) {
 601             queue_tx(sw, ofputil_encode_packet_out(&po, sw->protocol));
 602         }
 603     }
 604 }
 605
 606 static void
 607 process_echo_request(struct lswitch *sw, const struct ofp_header *rq)
 608 {
 609     queue_tx(sw, make_echo_reply(rq));
 610 }