zebra/label_manager.c

   1 /*
   2  * Label Manager for FRR
   3  *
   4  * Copyright (C) 2017 by Bingen Eguzkitza,
   5  *                       Volta Networks Inc.
   6  *
   7  * This file is part of FreeRangeRouting (FRR)
   8  *
   9  * FRR is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the
  11  * Free Software Foundation; either version 2, or (at your option) any
  12  * later version.
  13  *
  14  * FRR is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; see the file COPYING; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 #include <zebra.h>
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <sys/types.h>
  28
  29 #include "lib/log.h"
  30 #include "lib/memory.h"
  31 #include "lib/mpls.h"
  32 #include "lib/network.h"
  33 #include "lib/stream.h"
  34 #include "lib/zclient.h"
  35 #include "lib/libfrr.h"
  36
  37 //#include "zebra/zserv.h"
  38 #include "zebra/zebra_router.h"
  39 #include "zebra/label_manager.h"
  40 #include "zebra/zebra_errors.h"
  41
  42 #define CONNECTION_DELAY 5
  43
  44 struct label_manager lbl_mgr;
  45
  46 extern struct zebra_privs_t zserv_privs;
  47
  48 DEFINE_MGROUP(LBL_MGR, "Label Manager");
  49 DEFINE_MTYPE_STATIC(LBL_MGR, LM_CHUNK, "Label Manager Chunk");
  50
  51 /* In case this zebra daemon is not acting as label manager,
  52  * it will be a proxy to relay messages to external label manager
  53  * This zclient thus is to connect to it
  54  */
  55 static struct stream *obuf;
  56 static struct zclient *zclient;
  57 bool lm_is_external;
  58
  59 static void delete_label_chunk(void *val)
  60 {
  61         XFREE(MTYPE_LM_CHUNK, val);
  62 }
  63
  64 static int relay_response_back(void)
  65 {
  66         int ret = 0;
  67         struct stream *src, *dst;
  68         uint16_t size = 0;
  69         uint8_t marker;
  70         uint8_t version;
  71         vrf_id_t vrf_id;
  72         uint16_t resp_cmd;
  73         uint8_t proto;
  74         const char *proto_str;
  75         unsigned short instance;
  76         struct zserv *zserv;
  77
  78         /* input buffer with msg from label manager */
  79         src = zclient->ibuf;
  80
  81         stream_reset(src);
  82
  83         /* parse header */
  84         ret = zclient_read_header(src, zclient->sock, &size, &marker, &version,
  85                                   &vrf_id, &resp_cmd);
  86         if (ret < 0 && errno != EAGAIN) {
  87                 flog_err(EC_ZEBRA_LM_RESPONSE,
  88                          "Error reading Label Manager response: %s",
  89                          strerror(errno));
  90                 return -1;
  91         }
  92
  93         /* do not relay a msg that has nothing to do with LM */
  94         switch (resp_cmd) {
  95         case ZEBRA_LABEL_MANAGER_CONNECT:
  96         case ZEBRA_LABEL_MANAGER_CONNECT_ASYNC: /* should not be seen */
  97         case ZEBRA_GET_LABEL_CHUNK:
  98         case ZEBRA_RELEASE_LABEL_CHUNK:
  99                 break;
 100         default:
 101                 zlog_debug("Not relaying '%s' response (size %d) from LM",
 102                            zserv_command_string(resp_cmd), size);
 103                 return -1;
 104         }
 105
 106         zlog_debug("Received '%s' response (size %d) from LM",
 107                    zserv_command_string(resp_cmd), size);
 108
 109         if (size == 0)
 110                 return -1;
 111
 112         /* Get the 'proto' field of the message */
 113         proto = stream_getc(src);
 114
 115         /* Get the 'instance' field of the message */
 116         instance = stream_getw(src);
 117
 118         proto_str = zebra_route_string(proto);
 119
 120         /* lookup the client to relay the msg to */
 121         zserv = zserv_find_client(proto, instance);
 122         if (!zserv) {
 123                 flog_err(
 124                         EC_ZEBRA_LM_NO_SUCH_CLIENT,
 125                         "Error relaying LM response: can't find client %s, instance %u",
 126                         proto_str, instance);
 127                 return -1;
 128         }
 129         zlog_debug("Found client to relay LM response to client %s instance %u",
 130                    proto_str, instance);
 131
 132         /* copy msg into output buffer */
 133         dst = obuf;
 134         stream_copy(dst, src);
 135
 136         /* send response back */
 137         ret = writen(zserv->sock, dst->data, stream_get_endp(dst));
 138         if (ret <= 0) {
 139                 flog_err(EC_ZEBRA_LM_RELAY_FAILED,
 140                          "Error relaying LM response to %s instance %u: %s",
 141                          proto_str, instance, strerror(errno));
 142                 return -1;
 143         }
 144         zlog_debug("Relayed LM response (%d bytes) to %s instance %u", ret,
 145                    proto_str, instance);
 146
 147         return 0;
 148 }
 149
 150 static int lm_zclient_read(struct thread *t)
 151 {
 152         int ret;
 153
 154         zclient->t_read = NULL;
 155
 156         /* read response and send it back */
 157         ret = relay_response_back();
 158
 159         /* on error, schedule another read */
 160         if (ret == -1)
 161                 if (!zclient->t_read)
 162                         thread_add_read(zclient->master, lm_zclient_read, NULL,
 163                                         zclient->sock, &zclient->t_read);
 164         return ret;
 165 }
 166
 167 static int reply_error(int cmd, struct zserv *zserv, vrf_id_t vrf_id)
 168 {
 169         int ret;
 170         struct stream *s;
 171
 172         s = stream_new(ZEBRA_MAX_PACKET_SIZ);
 173
 174         zclient_create_header(s, cmd, vrf_id);
 175
 176         /* proto */
 177         stream_putc(s, zserv->proto);
 178         /* instance */
 179         stream_putw(s, zserv->instance);
 180         /* result */
 181         stream_putc(s, 1);
 182
 183         /* Write packet size. */
 184         stream_putw_at(s, 0, stream_get_endp(s));
 185
 186         ret = writen(zserv->sock, s->data, stream_get_endp(s));
 187
 188         stream_free(s);
 189         return ret;
 190 }
 191 /**
 192  * Receive a request to get or release a label chunk and forward it to external
 193  * label manager.
 194  *
 195  * It's called from zserv in case it's not an actual label manager, but just a
 196  * proxy.
 197  *
 198  * @param cmd Type of request (connect, get or release)
 199  * @param zserv
 200  * @return 0 on success, -1 otherwise
 201  */
 202 int zread_relay_label_manager_request(int cmd, struct zserv *zserv,
 203                                       struct stream *msg, vrf_id_t vrf_id)
 204 {
 205         struct stream *dst;
 206         int ret = 0;
 207         uint8_t proto;
 208         const char *proto_str;
 209         unsigned short instance;
 210
 211         if (zclient->sock < 0) {
 212                 flog_err(EC_ZEBRA_LM_NO_SOCKET,
 213                          "Unable to relay LM request: no socket");
 214                 reply_error(cmd, zserv, vrf_id);
 215                 return -1;
 216         }
 217
 218         /* peek msg to get proto and instance id. This zebra, which acts as
 219          * a proxy needs to have such values for each client in order to
 220          * relay responses back to it.
 221          */
 222
 223         /* Get the 'proto' field of incoming msg */
 224         proto = stream_getc(msg);
 225
 226         /* Get the 'instance' field of incoming msg */
 227         instance = stream_getw(msg);
 228
 229         /* stringify proto */
 230         proto_str = zebra_route_string(proto);
 231
 232         /* check & set client proto if unset */
 233         if (zserv->proto && zserv->proto != proto) {
 234                 flog_warn(EC_ZEBRAING_LM_PROTO_MISMATCH,
 235                           "Client proto(%u) != msg proto(%u)", zserv->proto,
 236                           proto);
 237                 return -1;
 238         }
 239
 240         /* check & set client instance if unset */
 241         if (zserv->instance && zserv->instance != instance) {
 242                 flog_err(EC_ZEBRA_LM_BAD_INSTANCE,
 243                          "Client instance(%u) != msg instance(%u)",
 244                          zserv->instance, instance);
 245                 return -1;
 246         }
 247
 248         /* recall proto and instance */
 249         zserv->instance = instance;
 250         zserv->proto = proto;
 251
 252         /* in case there's any incoming message enqueued, read and forward it */
 253         if (zserv->is_synchronous)
 254                 while (ret == 0)
 255                         ret = relay_response_back();
 256
 257         /* get the msg buffer used toward the 'master' Label Manager */
 258         dst = zclient->obuf;
 259
 260         /* copy the message */
 261         stream_copy(dst, msg);
 262
 263         /* Send request to external label manager */
 264         ret = writen(zclient->sock, dst->data, stream_get_endp(dst));
 265         if (ret <= 0) {
 266                 flog_err(EC_ZEBRA_LM_RELAY_FAILED,
 267                          "Error relaying LM request from %s instance %u: %s",
 268                          proto_str, instance, strerror(errno));
 269                 reply_error(cmd, zserv, vrf_id);
 270                 return -1;
 271         }
 272         zlog_debug("Relayed LM request (%d bytes) from %s instance %u", ret,
 273                    proto_str, instance);
 274
 275
 276         /* Release label chunk has no response */
 277         if (cmd == ZEBRA_RELEASE_LABEL_CHUNK)
 278                 return 0;
 279
 280         /* make sure we listen to the response */
 281         if (!zclient->t_read)
 282                 thread_add_read(zclient->master, lm_zclient_read, NULL,
 283                                 zclient->sock, &zclient->t_read);
 284
 285         return 0;
 286 }
 287
 288 static int lm_zclient_connect(struct thread *t)
 289 {
 290         zclient->t_connect = NULL;
 291
 292         if (zclient->sock >= 0)
 293                 return 0;
 294
 295         if (zclient_socket_connect(zclient) < 0) {
 296                 flog_err(EC_ZEBRA_LM_CLIENT_CONNECTION_FAILED,
 297                          "Error connecting synchronous zclient!");
 298                 thread_add_timer(zrouter.master, lm_zclient_connect, zclient,
 299                                  CONNECTION_DELAY, &zclient->t_connect);
 300                 return -1;
 301         }
 302
 303         /* make socket non-blocking */
 304         (void)set_nonblocking(zclient->sock);
 305
 306         return 0;
 307 }
 308
 309 /**
 310  * Function to initialize zclient in case this is not an actual
 311  * label manager, but just a proxy to an external one.
 312  *
 313  * @param lm_zserv_path Path to zserv socket of external label manager
 314  */
 315 static void lm_zclient_init(char *lm_zserv_path)
 316 {
 317         if (lm_zserv_path)
 318                 frr_zclient_addr(&zclient_addr, &zclient_addr_len,
 319                                  lm_zserv_path);
 320
 321         /* Set default values. */
 322         zclient = zclient_new(zrouter.master, &zclient_options_default);
 323         zclient->privs = &zserv_privs;
 324         zclient->sock = -1;
 325         zclient->t_connect = NULL;
 326         lm_zclient_connect(NULL);
 327 }
 328
 329 /**
 330  * Release label chunks from a client.
 331  *
 332  * Called on client disconnection or reconnection. It only releases chunks
 333  * with empty keep value.
 334  *
 335  * @param proto Daemon protocol of client, to identify the owner
 336  * @param instance Instance, to identify the owner
 337  * @return Number of chunks released
 338  */
 339 int release_daemon_label_chunks(struct zserv *client)
 340 {
 341         uint8_t proto = client->proto;
 342         uint16_t instance = client->instance;
 343         struct listnode *node;
 344         struct label_manager_chunk *lmc;
 345         int count = 0;
 346         int ret;
 347
 348         for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
 349                 if (lmc->proto == proto && lmc->instance == instance
 350                     && lmc->keep == 0) {
 351                         ret = release_label_chunk(lmc->proto, lmc->instance,
 352                                                   lmc->start, lmc->end);
 353                         if (ret == 0)
 354                                 count++;
 355                 }
 356         }
 357
 358         zlog_debug("%s: Released %d label chunks", __func__, count);
 359
 360         return count;
 361 }
 362
 363 /**
 364  * Init label manager (or proxy to an external one)
 365  */
 366 void label_manager_init(char *lm_zserv_path)
 367 {
 368         /* this is an actual label manager */
 369         if (!lm_zserv_path) {
 370                 zlog_debug("Initializing internal label manager");
 371                 lm_is_external = false;
 372                 lbl_mgr.lc_list = list_new();
 373                 lbl_mgr.lc_list->del = delete_label_chunk;
 374         } else { /* it's acting just as a proxy */
 375                 zlog_debug("Initializing external label manager at %s",
 376                            lm_zserv_path);
 377                 lm_is_external = true;
 378                 lm_zclient_init(lm_zserv_path);
 379         }
 380
 381         obuf = stream_new(ZEBRA_MAX_PACKET_SIZ);
 382
 383         hook_register(zserv_client_close, release_daemon_label_chunks);
 384 }
 385
 386 /**
 387  * Core function, assigns label cunks
 388  *
 389  * It first searches through the list to check if there's one available
 390  * (previously released). Otherwise it creates and assigns a new one
 391  *
 392  * @param proto Daemon protocol of client, to identify the owner
 393  * @param instance Instance, to identify the owner
 394  * @param keep If set, avoid garbage collection
 395  * @para size Size of the label chunk
 396  * @return Pointer to the assigned label chunk
 397  */
 398 struct label_manager_chunk *assign_label_chunk(uint8_t proto,
 399                                                unsigned short instance,
 400                                                uint8_t keep, uint32_t size)
 401 {
 402         struct label_manager_chunk *lmc;
 403         struct listnode *node;
 404
 405         /* first check if there's one available */
 406         for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
 407                 if (lmc->proto == NO_PROTO
 408                     && lmc->end - lmc->start + 1 == size) {
 409                         lmc->proto = proto;
 410                         lmc->instance = instance;
 411                         lmc->keep = keep;
 412                         return lmc;
 413                 }
 414         }
 415         /* otherwise create a new one */
 416         lmc = XCALLOC(MTYPE_LM_CHUNK, sizeof(struct label_manager_chunk));
 417
 418         if (list_isempty(lbl_mgr.lc_list))
 419                 lmc->start = MPLS_LABEL_UNRESERVED_MIN;
 420         else
 421                 lmc->start = ((struct label_manager_chunk *)listgetdata(
 422                                       listtail(lbl_mgr.lc_list)))
 423                                      ->end
 424                              + 1;
 425         if (lmc->start > MPLS_LABEL_UNRESERVED_MAX - size + 1) {
 426                 flog_err(EC_ZEBRA_LM_EXHAUSTED_LABELS,
 427                          "Reached max labels. Start: %u, size: %u", lmc->start,
 428                          size);
 429                 XFREE(MTYPE_LM_CHUNK, lmc);
 430                 return NULL;
 431         }
 432         lmc->end = lmc->start + size - 1;
 433         lmc->proto = proto;
 434         lmc->instance = instance;
 435         lmc->keep = keep;
 436         listnode_add(lbl_mgr.lc_list, lmc);
 437
 438         return lmc;
 439 }
 440
 441 /**
 442  * Core function, release no longer used label cunks
 443  *
 444  * @param proto Daemon protocol of client, to identify the owner
 445  * @param instance Instance, to identify the owner
 446  * @param start First label of the chunk
 447  * @param end Last label of the chunk
 448  * @return 0 on success, -1 otherwise
 449  */
 450 int release_label_chunk(uint8_t proto, unsigned short instance, uint32_t start,
 451                         uint32_t end)
 452 {
 453         struct listnode *node;
 454         struct label_manager_chunk *lmc;
 455         int ret = -1;
 456
 457         /* check that size matches */
 458         zlog_debug("Releasing label chunk: %u - %u", start, end);
 459         /* find chunk and disown */
 460         for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
 461                 if (lmc->start != start)
 462                         continue;
 463                 if (lmc->end != end)
 464                         continue;
 465                 if (lmc->proto != proto || lmc->instance != instance) {
 466                         flog_err(EC_ZEBRA_LM_DAEMON_MISMATCH,
 467                                  "%s: Daemon mismatch!!", __func__);
 468                         continue;
 469                 }
 470                 lmc->proto = NO_PROTO;
 471                 lmc->instance = 0;
 472                 lmc->keep = 0;
 473                 ret = 0;
 474                 break;
 475         }
 476         if (ret != 0)
 477                 flog_err(EC_ZEBRA_LM_UNRELEASED_CHUNK,
 478                          "%s: Label chunk not released!!", __func__);
 479
 480         return ret;
 481 }
 482
 483
 484 void label_manager_close(void)
 485 {
 486         list_delete(&lbl_mgr.lc_list);
 487         stream_free(obuf);
 488 }