lib/learning-switch.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira Networks.
   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-errors.h"
  33 #include "ofp-parse.h"
  34 #include "ofp-print.h"
  35 #include "ofp-util.h"
  36 #include "openflow/openflow.h"
  37 #include "poll-loop.h"
  38 #include "rconn.h"
  39 #include "shash.h"
  40 #include "timeval.h"
  41 #include "vconn.h"
  42 #include "vlog.h"
  43
  44 VLOG_DEFINE_THIS_MODULE(learning_switch);
  45
  46 struct lswitch_port {
  47     struct hmap_node hmap_node; /* Hash node for port number. */
  48     uint16_t port_no;           /* OpenFlow port number, in host byte order. */
  49     uint32_t queue_id;          /* OpenFlow queue number. */
  50 };
  51
  52 struct lswitch {
  53     /* If nonnegative, the switch sets up flows that expire after the given
  54      * number of seconds (or never expire, if the value is OFP_FLOW_PERMANENT).
  55      * Otherwise, the switch processes every packet. */
  56     int max_idle;
  57
  58     unsigned long long int datapath_id;
  59     time_t last_features_request;
  60     struct mac_learning *ml;    /* NULL to act as hub instead of switch. */
  61     struct flow_wildcards wc;   /* Wildcards to apply to flows. */
  62     bool action_normal;         /* Use OFPP_NORMAL? */
  63
  64     /* Queue distribution. */
  65     uint32_t default_queue;     /* Default OpenFlow queue, or UINT32_MAX. */
  66     struct hmap queue_numbers;  /* Map from port number to lswitch_port. */
  67     struct shash queue_names;   /* Map from port name to lswitch_port. */
  68
  69     /* Number of outgoing queued packets on the rconn. */
  70     struct rconn_packet_counter *queued;
  71 };
  72
  73 /* The log messages here could actually be useful in debugging, so keep the
  74  * rate limit relatively high. */
  75 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(30, 300);
  76
  77 static void queue_tx(struct lswitch *, struct rconn *, struct ofpbuf *);
  78 static void send_features_request(struct lswitch *, struct rconn *);
  79
  80 static enum ofperr process_switch_features(struct lswitch *,
  81                                            struct ofp_switch_features *);
  82 static void process_packet_in(struct lswitch *, struct rconn *,
  83                               const struct ofp_packet_in *);
  84 static void process_echo_request(struct lswitch *, struct rconn *,
  85                                  const struct ofp_header *);
  86
  87 /* Creates and returns a new learning switch whose configuration is given by
  88  * 'cfg'.
  89  *
  90  * 'rconn' is used to send out an OpenFlow features request. */
  91 struct lswitch *
  92 lswitch_create(struct rconn *rconn, const struct lswitch_config *cfg)
  93 {
  94     struct lswitch *sw;
  95
  96     sw = xzalloc(sizeof *sw);
  97     sw->max_idle = cfg->max_idle;
  98     sw->datapath_id = 0;
  99     sw->last_features_request = time_now() - 1;
 100     sw->ml = (cfg->mode == LSW_LEARN
 101               ? mac_learning_create(MAC_ENTRY_DEFAULT_IDLE_TIME)
 102               : NULL);
 103     sw->action_normal = cfg->mode == LSW_NORMAL;
 104
 105     flow_wildcards_init_exact(&sw->wc);
 106     if (cfg->wildcards) {
 107         uint32_t ofpfw;
 108
 109         if (cfg->wildcards == UINT32_MAX) {
 110             /* Try to wildcard as many fields as possible, but we cannot
 111              * wildcard all fields.  We need in_port to detect moves.  We need
 112              * Ethernet source and dest and VLAN VID to do L2 learning. */
 113             ofpfw = (OFPFW_DL_TYPE | OFPFW_DL_VLAN_PCP
 114                      | OFPFW_NW_SRC_ALL | OFPFW_NW_DST_ALL
 115                      | OFPFW_NW_TOS | OFPFW_NW_PROTO
 116                      | OFPFW_TP_SRC | OFPFW_TP_DST);
 117         } else {
 118             ofpfw = cfg->wildcards;
 119         }
 120
 121         ofputil_wildcard_from_openflow(ofpfw, &sw->wc);
 122     }
 123
 124     sw->default_queue = cfg->default_queue;
 125     hmap_init(&sw->queue_numbers);
 126     shash_init(&sw->queue_names);
 127     if (cfg->port_queues) {
 128         struct shash_node *node;
 129
 130         SHASH_FOR_EACH (node, cfg->port_queues) {
 131             struct lswitch_port *port = xmalloc(sizeof *port);
 132             hmap_node_nullify(&port->hmap_node);
 133             port->queue_id = (uintptr_t) node->data;
 134             shash_add(&sw->queue_names, node->name, port);
 135         }
 136     }
 137
 138     sw->queued = rconn_packet_counter_create();
 139     send_features_request(sw, rconn);
 140
 141     if (cfg->default_flows) {
 142         enum ofputil_protocol usable_protocols;
 143         enum ofputil_protocol protocol;
 144         struct ofpbuf *msg = NULL;
 145         int ofp_version;
 146         int error = 0;
 147         size_t i;
 148
 149         /* Figure out the initial protocol on the connection. */
 150         ofp_version = rconn_get_version(rconn);
 151         protocol = ofputil_protocol_from_ofp_version(ofp_version);
 152
 153         /* If the initial protocol isn't good enough for default_flows, then
 154          * pick one that will work and encode messages to set up that
 155          * protocol.
 156          *
 157          * This could be improved by actually negotiating a mutually acceptable
 158          * flow format with the switch, but that would require an asynchronous
 159          * state machine.  This version ought to work fine in practice. */
 160         usable_protocols = ofputil_flow_mod_usable_protocols(
 161             cfg->default_flows, cfg->n_default_flows);
 162         if (!(protocol & usable_protocols)) {
 163             enum ofputil_protocol want = rightmost_1bit(usable_protocols);
 164             while (!error) {
 165                 msg = ofputil_encode_set_protocol(protocol, want, &protocol);
 166                 if (!msg) {
 167                     break;
 168                 }
 169                 error = rconn_send(rconn, msg, NULL);
 170             }
 171         }
 172
 173         for (i = 0; !error && i < cfg->n_default_flows; i++) {
 174             msg = ofputil_encode_flow_mod(&cfg->default_flows[i], protocol);
 175             error = rconn_send(rconn, msg, NULL);
 176         }
 177
 178         if (error) {
 179             VLOG_INFO_RL(&rl, "%s: failed to queue default flows (%s)",
 180                          rconn_get_name(rconn), strerror(error));
 181         }
 182     }
 183
 184     return sw;
 185 }
 186
 187 /* Destroys 'sw'. */
 188 void
 189 lswitch_destroy(struct lswitch *sw)
 190 {
 191     if (sw) {
 192         struct lswitch_port *node, *next;
 193
 194         HMAP_FOR_EACH_SAFE (node, next, hmap_node, &sw->queue_numbers) {
 195             hmap_remove(&sw->queue_numbers, &node->hmap_node);
 196             free(node);
 197         }
 198         shash_destroy(&sw->queue_names);
 199         mac_learning_destroy(sw->ml);
 200         rconn_packet_counter_destroy(sw->queued);
 201         free(sw);
 202     }
 203 }
 204
 205 /* Takes care of necessary 'sw' activity, except for receiving packets (which
 206  * the caller must do). */
 207 void
 208 lswitch_run(struct lswitch *sw)
 209 {
 210     if (sw->ml) {
 211         mac_learning_run(sw->ml, NULL);
 212     }
 213 }
 214
 215 void
 216 lswitch_wait(struct lswitch *sw)
 217 {
 218     if (sw->ml) {
 219         mac_learning_wait(sw->ml);
 220     }
 221 }
 222
 223 /* Processes 'msg', which should be an OpenFlow received on 'rconn', according
 224  * to the learning switch state in 'sw'.  The most likely result of processing
 225  * is that flow-setup and packet-out OpenFlow messages will be sent out on
 226  * 'rconn'.  */
 227 void
 228 lswitch_process_packet(struct lswitch *sw, struct rconn *rconn,
 229                        const struct ofpbuf *msg)
 230 {
 231     const struct ofp_header *oh = msg->data;
 232     const struct ofputil_msg_type *type;
 233
 234     if (sw->datapath_id == 0
 235         && oh->type != OFPT_ECHO_REQUEST
 236         && oh->type != OFPT_FEATURES_REPLY) {
 237         send_features_request(sw, rconn);
 238         return;
 239     }
 240
 241     ofputil_decode_msg_type(oh, &type);
 242     switch (ofputil_msg_type_code(type)) {
 243     case OFPUTIL_OFPT_ECHO_REQUEST:
 244         process_echo_request(sw, rconn, msg->data);
 245         break;
 246
 247     case OFPUTIL_OFPT_FEATURES_REPLY:
 248         process_switch_features(sw, msg->data);
 249         break;
 250
 251     case OFPUTIL_OFPT_PACKET_IN:
 252         process_packet_in(sw, rconn, msg->data);
 253         break;
 254
 255     case OFPUTIL_OFPT_FLOW_REMOVED:
 256         /* Nothing to do. */
 257         break;
 258
 259     case OFPUTIL_MSG_INVALID:
 260     case OFPUTIL_OFPT_HELLO:
 261     case OFPUTIL_OFPT_ERROR:
 262     case OFPUTIL_OFPT_ECHO_REPLY:
 263     case OFPUTIL_OFPT_FEATURES_REQUEST:
 264     case OFPUTIL_OFPT_GET_CONFIG_REQUEST:
 265     case OFPUTIL_OFPT_GET_CONFIG_REPLY:
 266     case OFPUTIL_OFPT_SET_CONFIG:
 267     case OFPUTIL_OFPT_PORT_STATUS:
 268     case OFPUTIL_OFPT_PACKET_OUT:
 269     case OFPUTIL_OFPT_FLOW_MOD:
 270     case OFPUTIL_OFPT_PORT_MOD:
 271     case OFPUTIL_OFPT_BARRIER_REQUEST:
 272     case OFPUTIL_OFPT_BARRIER_REPLY:
 273     case OFPUTIL_OFPT_QUEUE_GET_CONFIG_REQUEST:
 274     case OFPUTIL_OFPT_QUEUE_GET_CONFIG_REPLY:
 275     case OFPUTIL_OFPST_DESC_REQUEST:
 276     case OFPUTIL_OFPST_FLOW_REQUEST:
 277     case OFPUTIL_OFPST_AGGREGATE_REQUEST:
 278     case OFPUTIL_OFPST_TABLE_REQUEST:
 279     case OFPUTIL_OFPST_PORT_REQUEST:
 280     case OFPUTIL_OFPST_QUEUE_REQUEST:
 281     case OFPUTIL_OFPST_DESC_REPLY:
 282     case OFPUTIL_OFPST_FLOW_REPLY:
 283     case OFPUTIL_OFPST_QUEUE_REPLY:
 284     case OFPUTIL_OFPST_PORT_REPLY:
 285     case OFPUTIL_OFPST_TABLE_REPLY:
 286     case OFPUTIL_OFPST_AGGREGATE_REPLY:
 287     case OFPUTIL_NXT_ROLE_REQUEST:
 288     case OFPUTIL_NXT_ROLE_REPLY:
 289     case OFPUTIL_NXT_FLOW_MOD_TABLE_ID:
 290     case OFPUTIL_NXT_SET_FLOW_FORMAT:
 291     case OFPUTIL_NXT_SET_PACKET_IN_FORMAT:
 292     case OFPUTIL_NXT_PACKET_IN:
 293     case OFPUTIL_NXT_FLOW_MOD:
 294     case OFPUTIL_NXT_FLOW_REMOVED:
 295     case OFPUTIL_NXT_FLOW_AGE:
 296     case OFPUTIL_NXT_SET_ASYNC_CONFIG:
 297     case OFPUTIL_NXT_SET_CONTROLLER_ID:
 298     case OFPUTIL_NXST_FLOW_REQUEST:
 299     case OFPUTIL_NXST_AGGREGATE_REQUEST:
 300     case OFPUTIL_NXST_FLOW_REPLY:
 301     case OFPUTIL_NXST_AGGREGATE_REPLY:
 302     default:
 303         if (VLOG_IS_DBG_ENABLED()) {
 304             char *s = ofp_to_string(msg->data, msg->size, 2);
 305             VLOG_DBG_RL(&rl, "%016llx: OpenFlow packet ignored: %s",
 306                         sw->datapath_id, s);
 307             free(s);
 308         }
 309     }
 310 }
 311 \f
 312 static void
 313 send_features_request(struct lswitch *sw, struct rconn *rconn)
 314 {
 315     time_t now = time_now();
 316     if (now >= sw->last_features_request + 1) {
 317         struct ofpbuf *b;
 318         struct ofp_switch_config *osc;
 319
 320         /* Send OFPT_FEATURES_REQUEST. */
 321         make_openflow(sizeof(struct ofp_header), OFPT_FEATURES_REQUEST, &b);
 322         queue_tx(sw, rconn, b);
 323
 324         /* Send OFPT_SET_CONFIG. */
 325         osc = make_openflow(sizeof *osc, OFPT_SET_CONFIG, &b);
 326         osc->miss_send_len = htons(OFP_DEFAULT_MISS_SEND_LEN);
 327         queue_tx(sw, rconn, b);
 328
 329         sw->last_features_request = now;
 330     }
 331 }
 332
 333 static void
 334 queue_tx(struct lswitch *sw, struct rconn *rconn, struct ofpbuf *b)
 335 {
 336     int retval = rconn_send_with_limit(rconn, b, sw->queued, 10);
 337     if (retval && retval != ENOTCONN) {
 338         if (retval == EAGAIN) {
 339             VLOG_INFO_RL(&rl, "%016llx: %s: tx queue overflow",
 340                          sw->datapath_id, rconn_get_name(rconn));
 341         } else {
 342             VLOG_WARN_RL(&rl, "%016llx: %s: send: %s",
 343                          sw->datapath_id, rconn_get_name(rconn),
 344                          strerror(retval));
 345         }
 346     }
 347 }
 348
 349 static enum ofperr
 350 process_switch_features(struct lswitch *sw, struct ofp_switch_features *osf)
 351 {
 352     struct ofputil_switch_features features;
 353     struct ofputil_phy_port port;
 354     enum ofperr error;
 355     struct ofpbuf b;
 356
 357     error = ofputil_decode_switch_features(osf, &features, &b);
 358     if (error) {
 359         VLOG_ERR("received invalid switch feature reply (%s)",
 360                  ofperr_to_string(error));
 361         return error;
 362     }
 363
 364     sw->datapath_id = features.datapath_id;
 365
 366     while (!ofputil_pull_switch_features_port(&b, &port)) {
 367         struct lswitch_port *lp = shash_find_data(&sw->queue_names, port.name);
 368         if (lp && hmap_node_is_null(&lp->hmap_node)) {
 369             lp->port_no = port.port_no;
 370             hmap_insert(&sw->queue_numbers, &lp->hmap_node,
 371                         hash_int(lp->port_no, 0));
 372         }
 373     }
 374     return 0;
 375 }
 376
 377 static uint16_t
 378 lswitch_choose_destination(struct lswitch *sw, const struct flow *flow)
 379 {
 380     uint16_t out_port;
 381
 382     /* Learn the source MAC. */
 383     if (mac_learning_may_learn(sw->ml, flow->dl_src, 0)) {
 384         struct mac_entry *mac = mac_learning_insert(sw->ml, flow->dl_src, 0);
 385         if (mac_entry_is_new(mac) || mac->port.i != flow->in_port) {
 386             VLOG_DBG_RL(&rl, "%016llx: learned that "ETH_ADDR_FMT" is on "
 387                         "port %"PRIu16, sw->datapath_id,
 388                         ETH_ADDR_ARGS(flow->dl_src), flow->in_port);
 389
 390             mac->port.i = flow->in_port;
 391             mac_learning_changed(sw->ml, mac);
 392         }
 393     }
 394
 395     /* Drop frames for reserved multicast addresses. */
 396     if (eth_addr_is_reserved(flow->dl_dst)) {
 397         return OFPP_NONE;
 398     }
 399
 400     out_port = OFPP_FLOOD;
 401     if (sw->ml) {
 402         struct mac_entry *mac;
 403
 404         mac = mac_learning_lookup(sw->ml, flow->dl_dst, 0, NULL);
 405         if (mac) {
 406             out_port = mac->port.i;
 407             if (out_port == flow->in_port) {
 408                 /* Don't send a packet back out its input port. */
 409                 return OFPP_NONE;
 410             }
 411         }
 412     }
 413
 414     /* Check if we need to use "NORMAL" action. */
 415     if (sw->action_normal && out_port != OFPP_FLOOD) {
 416         return OFPP_NORMAL;
 417     }
 418
 419     return out_port;
 420 }
 421
 422 static uint32_t
 423 get_queue_id(const struct lswitch *sw, uint16_t in_port)
 424 {
 425     const struct lswitch_port *port;
 426
 427     HMAP_FOR_EACH_WITH_HASH (port, hmap_node, hash_int(in_port, 0),
 428                              &sw->queue_numbers) {
 429         if (port->port_no == in_port) {
 430             return port->queue_id;
 431         }
 432     }
 433
 434     return sw->default_queue;
 435 }
 436
 437 static void
 438 process_packet_in(struct lswitch *sw, struct rconn *rconn,
 439                   const struct ofp_packet_in *opi)
 440 {
 441     uint16_t in_port = ntohs(opi->in_port);
 442     uint32_t queue_id;
 443     uint16_t out_port;
 444
 445     struct ofp_action_header actions[2];
 446     size_t actions_len;
 447
 448     struct ofputil_packet_out po;
 449
 450     size_t pkt_ofs, pkt_len;
 451     struct ofpbuf pkt;
 452     struct flow flow;
 453
 454     /* Ignore packets sent via output to OFPP_CONTROLLER.  This library never
 455      * uses such an action.  You never know what experiments might be going on,
 456      * though, and it seems best not to interfere with them. */
 457     if (opi->reason != OFPR_NO_MATCH) {
 458         return;
 459     }
 460
 461     /* Extract flow data from 'opi' into 'flow'. */
 462     pkt_ofs = offsetof(struct ofp_packet_in, data);
 463     pkt_len = ntohs(opi->header.length) - pkt_ofs;
 464     ofpbuf_use_const(&pkt, opi->data, pkt_len);
 465     flow_extract(&pkt, 0, 0, in_port, &flow);
 466
 467     /* Choose output port. */
 468     out_port = lswitch_choose_destination(sw, &flow);
 469
 470     /* Make actions. */
 471     queue_id = get_queue_id(sw, in_port);
 472     if (out_port == OFPP_NONE) {
 473         actions_len = 0;
 474     } else if (queue_id == UINT32_MAX || out_port >= OFPP_MAX) {
 475         struct ofp_action_output oao;
 476
 477         memset(&oao, 0, sizeof oao);
 478         oao.type = htons(OFPAT10_OUTPUT);
 479         oao.len = htons(sizeof oao);
 480         oao.port = htons(out_port);
 481
 482         memcpy(actions, &oao, sizeof oao);
 483         actions_len = sizeof oao;
 484     } else {
 485         struct ofp_action_enqueue oae;
 486
 487         memset(&oae, 0, sizeof oae);
 488         oae.type = htons(OFPAT10_ENQUEUE);
 489         oae.len = htons(sizeof oae);
 490         oae.port = htons(out_port);
 491         oae.queue_id = htonl(queue_id);
 492
 493         memcpy(actions, &oae, sizeof oae);
 494         actions_len = sizeof oae;
 495     }
 496     assert(actions_len <= sizeof actions);
 497
 498     /* Prepare packet_out in case we need one. */
 499     po.buffer_id = ntohl(opi->buffer_id);
 500     if (po.buffer_id == UINT32_MAX) {
 501         po.packet = pkt.data;
 502         po.packet_len = pkt.size;
 503     } else {
 504         po.packet = NULL;
 505         po.packet_len = 0;
 506     }
 507     po.in_port = in_port;
 508     po.actions = (union ofp_action *) actions;
 509     po.n_actions = actions_len / sizeof *actions;
 510
 511     /* Send the packet, and possibly the whole flow, to the output port. */
 512     if (sw->max_idle >= 0 && (!sw->ml || out_port != OFPP_FLOOD)) {
 513         struct ofpbuf *buffer;
 514         struct cls_rule rule;
 515
 516         /* The output port is known, or we always flood everything, so add a
 517          * new flow. */
 518         cls_rule_init(&flow, &sw->wc, 0, &rule);
 519         buffer = make_add_flow(&rule, ntohl(opi->buffer_id),
 520                                sw->max_idle, actions_len);
 521         ofpbuf_put(buffer, actions, actions_len);
 522         queue_tx(sw, rconn, buffer);
 523
 524         /* If the switch didn't buffer the packet, we need to send a copy. */
 525         if (ntohl(opi->buffer_id) == UINT32_MAX && actions_len > 0) {
 526             queue_tx(sw, rconn, ofputil_encode_packet_out(&po));
 527         }
 528     } else {
 529         /* We don't know that MAC, or we don't set up flows.  Send along the
 530          * packet without setting up a flow. */
 531         if (ntohl(opi->buffer_id) != UINT32_MAX || actions_len > 0) {
 532             queue_tx(sw, rconn, ofputil_encode_packet_out(&po));
 533         }
 534     }
 535 }
 536
 537 static void
 538 process_echo_request(struct lswitch *sw, struct rconn *rconn,
 539                      const struct ofp_header *rq)
 540 {
 541     queue_tx(sw, rconn, make_echo_reply(rq));
 542 }