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