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