lib/learning-switch.c

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