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