ofproto/in-band.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015 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 <arpa/inet.h>
  19 #include <errno.h>
  20 #include <inttypes.h>
  21 #include <sys/socket.h>
  22 #include <net/if.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25 #include "classifier.h"
  26 #include "dhcp.h"
  27 #include "flow.h"
  28 #include "in-band.h"
  29 #include "netdev.h"
  30 #include "netlink.h"
  31 #include "odp-util.h"
  32 #include "ofproto.h"
  33 #include "ofproto-provider.h"
  34 #include "openflow/openflow.h"
  35 #include "openvswitch/ofp-actions.h"
  36 #include "openvswitch/ofpbuf.h"
  37 #include "openvswitch/vlog.h"
  38 #include "packets.h"
  39 #include "poll-loop.h"
  40 #include "timeval.h"
  41
  42 VLOG_DEFINE_THIS_MODULE(in_band);
  43
  44 /* Priorities used in classifier for in-band rules.  These values are higher
  45  * than any that may be set with OpenFlow, and "18" kind of looks like "IB".
  46  * The ordering of priorities is not important because all of the rules set up
  47  * by in-band control have the same action.  The only reason to use more than
  48  * one priority is to make the kind of flow easier to see during debugging. */
  49 enum {
  50     /* One set per bridge. */
  51     IBR_FROM_LOCAL_DHCP = 180000, /* (a) From local port, DHCP. */
  52     IBR_TO_LOCAL_ARP,             /* (b) To local port, ARP. */
  53     IBR_FROM_LOCAL_ARP,           /* (c) From local port, ARP. */
  54
  55     /* One set per unique next-hop MAC. */
  56     IBR_TO_NEXT_HOP_ARP,          /* (d) To remote MAC, ARP. */
  57     IBR_FROM_NEXT_HOP_ARP,        /* (e) From remote MAC, ARP. */
  58
  59     /* One set per unique remote IP address. */
  60     IBR_TO_REMOTE_ARP,            /* (f) To remote IP, ARP. */
  61     IBR_FROM_REMOTE_ARP,          /* (g) From remote IP, ARP. */
  62
  63     /* One set per unique remote (IP,port) pair. */
  64     IBR_TO_REMOTE_TCP,            /* (h) To remote IP, TCP port. */
  65     IBR_FROM_REMOTE_TCP           /* (i) From remote IP, TCP port. */
  66 };
  67
  68 /* Track one remote IP and next hop information. */
  69 struct in_band_remote {
  70     struct sockaddr_in remote_addr;  /* IP address, in network byte order. */
  71     struct eth_addr remote_mac;      /* Next-hop MAC, all-zeros if unknown. */
  72     struct eth_addr last_remote_mac; /* Previous nonzero next-hop MAC. */
  73     struct netdev *remote_netdev;    /* Device to send to next-hop MAC. */
  74 };
  75
  76 /* What to do to an in_band_rule. */
  77 enum in_band_op {
  78     ADD,                       /* Add the rule to ofproto's flow table. */
  79     DEL                        /* Delete the rule from ofproto's flow table. */
  80 };
  81
  82 /* A rule to add to or delete from ofproto's flow table.  */
  83 struct in_band_rule {
  84     struct hmap_node hmap_node; /* In struct in_band's "rules" hmap. */
  85     struct match match;
  86     int priority;
  87     enum in_band_op op;
  88 };
  89
  90 struct in_band {
  91     struct ofproto *ofproto;
  92     int queue_id;
  93
  94     /* Remote information. */
  95     time_t next_remote_refresh; /* Refresh timer. */
  96     struct in_band_remote *remotes;
  97     size_t n_remotes;
  98
  99     /* Local information. */
 100     time_t next_local_refresh;       /* Refresh timer. */
 101     struct eth_addr local_mac;       /* Current MAC. */
 102     struct netdev *local_netdev;     /* Local port's network device. */
 103
 104     /* Flow tracking. */
 105     struct hmap rules;          /* Contains "struct in_band_rule"s. */
 106 };
 107
 108 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(60, 60);
 109
 110 static int
 111 refresh_remote(struct in_band *ib, struct in_band_remote *r)
 112 {
 113     struct in_addr next_hop_inaddr;
 114     char *next_hop_dev;
 115     int retval;
 116
 117     /* Find the next-hop IP address. */
 118     r->remote_mac = eth_addr_zero;
 119     retval = netdev_get_next_hop(ib->local_netdev, &r->remote_addr.sin_addr,
 120                                  &next_hop_inaddr, &next_hop_dev);
 121     if (retval) {
 122         VLOG_WARN("%s: cannot find route for controller ("IP_FMT"): %s",
 123                   ib->ofproto->name, IP_ARGS(r->remote_addr.sin_addr.s_addr),
 124                   ovs_strerror(retval));
 125         return 1;
 126     }
 127     if (!next_hop_inaddr.s_addr) {
 128         next_hop_inaddr = r->remote_addr.sin_addr;
 129     }
 130
 131     /* Open the next-hop network device. */
 132     if (!r->remote_netdev
 133         || strcmp(netdev_get_name(r->remote_netdev), next_hop_dev))
 134     {
 135         netdev_close(r->remote_netdev);
 136
 137         retval = netdev_open(next_hop_dev, NULL, &r->remote_netdev);
 138         if (retval) {
 139             VLOG_WARN_RL(&rl, "%s: cannot open netdev %s (next hop "
 140                          "to controller "IP_FMT"): %s",
 141                          ib->ofproto->name, next_hop_dev,
 142                          IP_ARGS(r->remote_addr.sin_addr.s_addr),
 143                          ovs_strerror(retval));
 144             free(next_hop_dev);
 145             return 1;
 146         }
 147     }
 148     free(next_hop_dev);
 149
 150     /* Look up the MAC address of the next-hop IP address. */
 151     retval = netdev_arp_lookup(r->remote_netdev, next_hop_inaddr.s_addr,
 152                                &r->remote_mac);
 153     if (retval) {
 154         VLOG_DBG_RL(&rl, "%s: cannot look up remote MAC address ("IP_FMT"): %s",
 155                     ib->ofproto->name, IP_ARGS(next_hop_inaddr.s_addr),
 156                     ovs_strerror(retval));
 157     }
 158
 159     /* If we don't have a MAC address, then refresh quickly, since we probably
 160      * will get a MAC address soon (via ARP).  Otherwise, we can afford to wait
 161      * a little while. */
 162     return eth_addr_is_zero(r->remote_mac) ? 1 : 10;
 163 }
 164
 165 static bool
 166 refresh_remotes(struct in_band *ib)
 167 {
 168     struct in_band_remote *r;
 169     bool any_changes;
 170
 171     if (time_now() < ib->next_remote_refresh) {
 172         return false;
 173     }
 174
 175     any_changes = false;
 176     ib->next_remote_refresh = TIME_MAX;
 177     for (r = ib->remotes; r < &ib->remotes[ib->n_remotes]; r++) {
 178         struct eth_addr old_remote_mac;
 179         time_t next_refresh;
 180
 181         /* Save old MAC. */
 182         old_remote_mac = r->remote_mac;
 183
 184         /* Refresh remote information. */
 185         next_refresh = refresh_remote(ib, r) + time_now();
 186         ib->next_remote_refresh = MIN(ib->next_remote_refresh, next_refresh);
 187
 188         /* If the MAC changed, log the changes. */
 189         if (!eth_addr_equals(r->remote_mac, old_remote_mac)) {
 190             any_changes = true;
 191             if (!eth_addr_is_zero(r->remote_mac)
 192                 && !eth_addr_equals(r->last_remote_mac, r->remote_mac)) {
 193                 VLOG_DBG("%s: remote MAC address changed from "ETH_ADDR_FMT
 194                          " to "ETH_ADDR_FMT,
 195                          ib->ofproto->name,
 196                          ETH_ADDR_ARGS(r->last_remote_mac),
 197                          ETH_ADDR_ARGS(r->remote_mac));
 198                 r->last_remote_mac = r->remote_mac;
 199             }
 200         }
 201     }
 202
 203     return any_changes;
 204 }
 205
 206 /* Refreshes the MAC address of the local port into ib->local_mac, if it is due
 207  * for a refresh.  Returns true if anything changed, otherwise false.  */
 208 static bool
 209 refresh_local(struct in_band *ib)
 210 {
 211     struct eth_addr ea;
 212     time_t now;
 213
 214     now = time_now();
 215     if (now < ib->next_local_refresh) {
 216         return false;
 217     }
 218     ib->next_local_refresh = now + 1;
 219
 220     if (netdev_get_etheraddr(ib->local_netdev, &ea)
 221         || eth_addr_equals(ea, ib->local_mac)) {
 222         return false;
 223     }
 224
 225     ib->local_mac = ea;
 226     return true;
 227 }
 228
 229 /* Returns true if packets in 'flow' should be directed to the local port.
 230  * (This keeps the flow table from preventing DHCP replies from being seen by
 231  * the local port.) */
 232 bool
 233 in_band_must_output_to_local_port(const struct flow *flow)
 234 {
 235     return (flow->dl_type == htons(ETH_TYPE_IP)
 236             && flow->nw_proto == IPPROTO_UDP
 237             && flow->tp_src == htons(DHCP_SERVER_PORT)
 238             && flow->tp_dst == htons(DHCP_CLIENT_PORT));
 239 }
 240
 241 /* Returns the number of in-band rules currently installed in the flow
 242  * table. */
 243 int
 244 in_band_count_rules(const struct in_band *ib)
 245 {
 246     return hmap_count(&ib->rules);
 247 }
 248
 249 static void
 250 add_rule(struct in_band *ib, const struct match *match, int priority)
 251 {
 252     uint32_t hash = match_hash(match, 0);
 253     struct in_band_rule *rule;
 254
 255     HMAP_FOR_EACH_WITH_HASH (rule, hmap_node, hash, &ib->rules) {
 256         if (match_equal(&rule->match, match)) {
 257             rule->op = ADD;
 258             return;
 259         }
 260     }
 261
 262     rule = xmalloc(sizeof *rule);
 263     rule->match = *match;
 264     rule->priority = priority;
 265     rule->op = ADD;
 266     hmap_insert(&ib->rules, &rule->hmap_node, hash);
 267 }
 268
 269 static void
 270 update_rules(struct in_band *ib)
 271 {
 272     struct in_band_rule *ib_rule;
 273     struct in_band_remote *r;
 274     struct match match;
 275
 276     /* Mark all the existing rules for deletion.  (Afterward we will re-add any
 277      * rules that are still valid.) */
 278     HMAP_FOR_EACH (ib_rule, hmap_node, &ib->rules) {
 279         ib_rule->op = DEL;
 280     }
 281
 282     if (ib->n_remotes && !eth_addr_is_zero(ib->local_mac)) {
 283         /* (a) Allow DHCP requests sent from the local port. */
 284         match_init_catchall(&match);
 285         match_set_in_port(&match, OFPP_LOCAL);
 286         match_set_dl_type(&match, htons(ETH_TYPE_IP));
 287         match_set_dl_src(&match, ib->local_mac);
 288         match_set_nw_proto(&match, IPPROTO_UDP);
 289         match_set_tp_src(&match, htons(DHCP_CLIENT_PORT));
 290         match_set_tp_dst(&match, htons(DHCP_SERVER_PORT));
 291         add_rule(ib, &match, IBR_FROM_LOCAL_DHCP);
 292
 293         /* (b) Allow ARP replies to the local port's MAC address. */
 294         match_init_catchall(&match);
 295         match_set_dl_type(&match, htons(ETH_TYPE_ARP));
 296         match_set_dl_dst(&match, ib->local_mac);
 297         match_set_nw_proto(&match, ARP_OP_REPLY);
 298         add_rule(ib, &match, IBR_TO_LOCAL_ARP);
 299
 300         /* (c) Allow ARP requests from the local port's MAC address.  */
 301         match_init_catchall(&match);
 302         match_set_dl_type(&match, htons(ETH_TYPE_ARP));
 303         match_set_dl_src(&match, ib->local_mac);
 304         match_set_nw_proto(&match, ARP_OP_REQUEST);
 305         add_rule(ib, &match, IBR_FROM_LOCAL_ARP);
 306     }
 307
 308     for (r = ib->remotes; r < &ib->remotes[ib->n_remotes]; r++) {
 309         if (eth_addr_is_zero(r->remote_mac)) {
 310             continue;
 311         }
 312
 313         /* (d) Allow ARP replies to the next hop's MAC address. */
 314         match_init_catchall(&match);
 315         match_set_dl_type(&match, htons(ETH_TYPE_ARP));
 316         match_set_dl_dst(&match, r->remote_mac);
 317         match_set_nw_proto(&match, ARP_OP_REPLY);
 318         add_rule(ib, &match, IBR_TO_NEXT_HOP_ARP);
 319
 320         /* (e) Allow ARP requests from the next hop's MAC address. */
 321         match_init_catchall(&match);
 322         match_set_dl_type(&match, htons(ETH_TYPE_ARP));
 323         match_set_dl_src(&match, r->remote_mac);
 324         match_set_nw_proto(&match, ARP_OP_REQUEST);
 325         add_rule(ib, &match, IBR_FROM_NEXT_HOP_ARP);
 326     }
 327
 328     for (r = ib->remotes; r < &ib->remotes[ib->n_remotes]; r++) {
 329         const struct sockaddr_in *a = &r->remote_addr;
 330
 331         /* (f) Allow ARP replies containing the remote's IP address as a
 332          * target. */
 333         match_init_catchall(&match);
 334         match_set_dl_type(&match, htons(ETH_TYPE_ARP));
 335         match_set_nw_proto(&match, ARP_OP_REPLY);
 336         match_set_nw_dst(&match, a->sin_addr.s_addr);
 337         add_rule(ib, &match, IBR_TO_REMOTE_ARP);
 338
 339         /* (g) Allow ARP requests containing the remote's IP address as a
 340          * source. */
 341         match_init_catchall(&match);
 342         match_set_dl_type(&match, htons(ETH_TYPE_ARP));
 343         match_set_nw_proto(&match, ARP_OP_REQUEST);
 344         match_set_nw_src(&match, a->sin_addr.s_addr);
 345         add_rule(ib, &match, IBR_FROM_REMOTE_ARP);
 346
 347         /* (h) Allow TCP traffic to the remote's IP and port. */
 348         match_init_catchall(&match);
 349         match_set_dl_type(&match, htons(ETH_TYPE_IP));
 350         match_set_nw_proto(&match, IPPROTO_TCP);
 351         match_set_nw_dst(&match, a->sin_addr.s_addr);
 352         match_set_tp_dst(&match, a->sin_port);
 353         add_rule(ib, &match, IBR_TO_REMOTE_TCP);
 354
 355         /* (i) Allow TCP traffic from the remote's IP and port. */
 356         match_init_catchall(&match);
 357         match_set_dl_type(&match, htons(ETH_TYPE_IP));
 358         match_set_nw_proto(&match, IPPROTO_TCP);
 359         match_set_nw_src(&match, a->sin_addr.s_addr);
 360         match_set_tp_src(&match, a->sin_port);
 361         add_rule(ib, &match, IBR_FROM_REMOTE_TCP);
 362     }
 363 }
 364
 365 /* Updates the OpenFlow flow table for the current state of in-band control.
 366  * Returns true ordinarily.  Returns false if no remotes are configured on 'ib'
 367  * and 'ib' doesn't have any rules left to remove from the OpenFlow flow
 368  * table.  Thus, a false return value means that the caller can destroy 'ib'
 369  * without leaving extra flows hanging around in the flow table. */
 370 bool
 371 in_band_run(struct in_band *ib)
 372 {
 373     uint64_t ofpacts_stub[128 / 8];
 374     struct ofpbuf ofpacts;
 375
 376     struct in_band_rule *rule, *next;
 377
 378     ofpbuf_use_stub(&ofpacts, ofpacts_stub, sizeof ofpacts_stub);
 379
 380     if (ib->queue_id >= 0) {
 381         ofpact_put_SET_QUEUE(&ofpacts)->queue_id = ib->queue_id;
 382     }
 383     ofpact_put_OUTPUT(&ofpacts)->port = OFPP_NORMAL;
 384
 385     refresh_local(ib);
 386     refresh_remotes(ib);
 387
 388     update_rules(ib);
 389
 390     HMAP_FOR_EACH_SAFE (rule, next, hmap_node, &ib->rules) {
 391         switch (rule->op) {
 392         case ADD:
 393             ofproto_add_flow(ib->ofproto, &rule->match, rule->priority,
 394                              ofpacts.data, ofpacts.size);
 395             break;
 396
 397         case DEL:
 398             ofproto_delete_flow(ib->ofproto, &rule->match, rule->priority);
 399             hmap_remove(&ib->rules, &rule->hmap_node);
 400             free(rule);
 401             break;
 402         }
 403     }
 404
 405     ofpbuf_uninit(&ofpacts);
 406
 407     return ib->n_remotes || !hmap_is_empty(&ib->rules);
 408 }
 409
 410 void
 411 in_band_wait(struct in_band *in_band)
 412 {
 413     long long int wakeup
 414             = MIN(in_band->next_remote_refresh, in_band->next_local_refresh);
 415     poll_timer_wait_until(wakeup * 1000);
 416 }
 417
 418 int
 419 in_band_create(struct ofproto *ofproto, const char *local_name,
 420                struct in_band **in_bandp)
 421 {
 422     struct in_band *in_band;
 423     struct netdev *local_netdev;
 424     int error;
 425     const char *type = ofproto_port_open_type(ofproto->type, "internal");
 426
 427     *in_bandp = NULL;
 428     error = netdev_open(local_name, type, &local_netdev);
 429     if (error) {
 430         VLOG_ERR("%s: failed to initialize in-band control: cannot open "
 431                  "datapath local port %s (%s)", ofproto->name,
 432                  local_name, ovs_strerror(error));
 433         return error;
 434     }
 435
 436     in_band = xzalloc(sizeof *in_band);
 437     in_band->ofproto = ofproto;
 438     in_band->queue_id = -1;
 439     in_band->next_remote_refresh = TIME_MIN;
 440     in_band->next_local_refresh = TIME_MIN;
 441     in_band->local_netdev = local_netdev;
 442     hmap_init(&in_band->rules);
 443
 444     *in_bandp = in_band;
 445
 446     return 0;
 447 }
 448
 449 void
 450 in_band_destroy(struct in_band *ib)
 451 {
 452     if (ib) {
 453         struct in_band_rule *rule;
 454
 455         HMAP_FOR_EACH_POP (rule, hmap_node, &ib->rules) {
 456             free(rule);
 457         }
 458         hmap_destroy(&ib->rules);
 459         in_band_set_remotes(ib, NULL, 0);
 460         netdev_close(ib->local_netdev);
 461         free(ib);
 462     }
 463 }
 464
 465 static bool
 466 any_addresses_changed(struct in_band *ib,
 467                       const struct sockaddr_in *addresses, size_t n)
 468 {
 469     size_t i;
 470
 471     if (n != ib->n_remotes) {
 472         return true;
 473     }
 474
 475     for (i = 0; i < n; i++) {
 476         const struct sockaddr_in *old = &ib->remotes[i].remote_addr;
 477         const struct sockaddr_in *new = &addresses[i];
 478
 479         if (old->sin_addr.s_addr != new->sin_addr.s_addr ||
 480             old->sin_port != new->sin_port) {
 481             return true;
 482         }
 483     }
 484
 485     return false;
 486 }
 487
 488 void
 489 in_band_set_remotes(struct in_band *ib,
 490                     const struct sockaddr_in *addresses, size_t n)
 491 {
 492     size_t i;
 493
 494     if (!any_addresses_changed(ib, addresses, n)) {
 495         return;
 496     }
 497
 498     /* Clear old remotes. */
 499     for (i = 0; i < ib->n_remotes; i++) {
 500         netdev_close(ib->remotes[i].remote_netdev);
 501     }
 502     free(ib->remotes);
 503
 504     /* Set up new remotes. */
 505     ib->remotes = n ? xzalloc(n * sizeof *ib->remotes) : NULL;
 506     ib->n_remotes = n;
 507     for (i = 0; i < n; i++) {
 508         ib->remotes[i].remote_addr = addresses[i];
 509     }
 510
 511     /* Force refresh in next call to in_band_run(). */
 512     ib->next_remote_refresh = TIME_MIN;
 513 }
 514
 515 /* Sets the OpenFlow queue used by flows set up by 'ib' to 'queue_id'.  If
 516  * 'queue_id' is negative, 'ib' will not set any queue (which is also the
 517  * default). */
 518 void
 519 in_band_set_queue(struct in_band *ib, int queue_id)
 520 {
 521     ib->queue_id = queue_id;
 522 }
 523