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
  37 #include "label_manager.h"
  38
  39 #define CONNECTION_DELAY 5
  40
  41 struct label_manager lbl_mgr;
  42
  43 DEFINE_MGROUP(LBL_MGR, "Label Manager");
  44 DEFINE_MTYPE_STATIC(LBL_MGR, LM_CHUNK, "Label Manager Chunk");
  45
  46 /* In case this zebra daemon is not acting as label manager,
  47  * it will be a proxy to relay messages to external label manager
  48  * This zclient thus is to connect to it
  49  */
  50 static struct zclient *zclient;
  51 bool lm_is_external;
  52
  53 static void delete_label_chunk(void *val)
  54 {
  55         XFREE(MTYPE_LM_CHUNK, val);
  56 }
  57
  58 static int relay_response_back(struct zserv *zserv)
  59 {
  60         int ret = 0;
  61         struct stream *src, *dst;
  62         u_int16_t size = 0;
  63         u_char marker;
  64         u_char version;
  65         vrf_id_t vrf_id;
  66         u_int16_t resp_cmd;
  67
  68         src = zclient->ibuf;
  69         dst = zserv->obuf;
  70
  71         stream_reset(src);
  72
  73         ret = zclient_read_header(src, zclient->sock, &size, &marker, &version,
  74                                   &vrf_id, &resp_cmd);
  75         if (ret < 0 && errno != EAGAIN) {
  76                 zlog_err("%s: Error reading Label Manager response: %s",
  77                          __func__, strerror(errno));
  78                 return -1;
  79         }
  80         zlog_debug("%s: Label Manager response received, %d bytes", __func__,
  81                    size);
  82         if (size == 0)
  83                 return -1;
  84
  85         /* send response back */
  86         stream_copy(dst, src);
  87         ret = writen(zserv->sock, dst->data, stream_get_endp(dst));
  88         if (ret <= 0) {
  89                 zlog_err("%s: Error sending Label Manager response back: %s",
  90                          __func__, strerror(errno));
  91                 return -1;
  92         }
  93         zlog_debug("%s: Label Manager response (%d bytes) sent back", __func__,
  94                    ret);
  95
  96         return 0;
  97 }
  98
  99 static int lm_zclient_read(struct thread *t)
 100 {
 101         struct zserv *zserv;
 102         int ret;
 103
 104         /* Get socket to zebra. */
 105         zserv = THREAD_ARG(t);
 106         zclient->t_read = NULL;
 107
 108         /* read response and send it back */
 109         ret = relay_response_back(zserv);
 110
 111         return ret;
 112 }
 113
 114 static int reply_error(int cmd, struct zserv *zserv, vrf_id_t vrf_id)
 115 {
 116         struct stream *s;
 117
 118         s = zserv->obuf;
 119         stream_reset(s);
 120
 121         zserv_create_header(s, cmd, vrf_id);
 122
 123         /* result */
 124         stream_putc(s, 1);
 125
 126         /* Write packet size. */
 127         stream_putw_at(s, 0, stream_get_endp(s));
 128
 129         return writen(zserv->sock, s->data, stream_get_endp(s));
 130 }
 131 /**
 132  * Receive a request to get or release a label chunk and forward it to external
 133  * label manager.
 134  *
 135  * It's called from zserv in case it's not an actual label manager, but just a
 136  * proxy.
 137  *
 138  * @param cmd Type of request (connect, get or release)
 139  * @param zserv
 140  * @return 0 on success, -1 otherwise
 141  */
 142 int zread_relay_label_manager_request(int cmd, struct zserv *zserv,
 143                                       vrf_id_t vrf_id)
 144 {
 145         struct stream *src, *dst;
 146         int ret = 0;
 147
 148         if (zclient->sock < 0) {
 149                 zlog_err(
 150                         "%s: Error relaying label chunk request: no zclient socket",
 151                         __func__);
 152                 reply_error(cmd, zserv, vrf_id);
 153                 return -1;
 154         }
 155
 156         /* in case there's any incoming message enqueued, read and forward it */
 157         while (ret == 0)
 158                 ret = relay_response_back(zserv);
 159
 160         /* Send request to external label manager */
 161         src = zserv->ibuf;
 162         dst = zclient->obuf;
 163
 164         stream_copy(dst, src);
 165
 166         ret = writen(zclient->sock, dst->data, stream_get_endp(dst));
 167         if (ret <= 0) {
 168                 zlog_err("%s: Error relaying label chunk request: %s", __func__,
 169                          strerror(errno));
 170                 reply_error(cmd, zserv, vrf_id);
 171                 return -1;
 172         }
 173         zlog_debug("%s: Label chunk request relayed. %d bytes sent", __func__,
 174                    ret);
 175
 176         /* Release label chunk has no response */
 177         if (cmd == ZEBRA_RELEASE_LABEL_CHUNK)
 178                 return 0;
 179
 180         /* make sure we listen to the response */
 181         if (!zclient->t_read)
 182                 thread_add_read(zclient->master, lm_zclient_read, zserv,
 183                                 zclient->sock, &zclient->t_read);
 184
 185         return 0;
 186 }
 187
 188 static int lm_zclient_connect(struct thread *t)
 189 {
 190         zclient->t_connect = NULL;
 191
 192         if (zclient->sock >= 0)
 193                 return 0;
 194
 195         if (zclient_socket_connect(zclient) < 0) {
 196                 zlog_err("Error connecting synchronous zclient!");
 197                 thread_add_timer(zebrad.master, lm_zclient_connect, zclient,
 198                                  CONNECTION_DELAY, &zclient->t_connect);
 199                 return -1;
 200         }
 201
 202         /* make socket non-blocking */
 203         if (set_nonblocking(zclient->sock) < 0)
 204                 zlog_warn("%s: set_nonblocking(%d) failed", __func__,
 205                           zclient->sock);
 206
 207         return 0;
 208 }
 209
 210 /**
 211  * Function to initialize zclient in case this is not an actual
 212  * label manager, but just a proxy to an external one.
 213  *
 214  * @param lm_zserv_path Path to zserv socket of external label manager
 215  */
 216 static void lm_zclient_init(char *lm_zserv_path)
 217 {
 218         if (lm_zserv_path)
 219                 zclient_serv_path_set(lm_zserv_path);
 220
 221         /* Set default values. */
 222         zclient = zclient_new(zebrad.master);
 223         zclient->sock = -1;
 224         zclient->t_connect = NULL;
 225         lm_zclient_connect(NULL);
 226 }
 227
 228 /**
 229  * Init label manager (or proxy to an external one)
 230  */
 231 void label_manager_init(char *lm_zserv_path)
 232 {
 233         /* this is an actual label manager */
 234         if (!lm_zserv_path) {
 235                 zlog_debug("Initializing own label manager");
 236                 lm_is_external = false;
 237                 lbl_mgr.lc_list = list_new();
 238                 lbl_mgr.lc_list->del = delete_label_chunk;
 239         } else { /* it's acting just as a proxy */
 240                 zlog_debug("Initializing external label manager at %s",
 241                            lm_zserv_path);
 242                 lm_is_external = true;
 243                 lm_zclient_init(lm_zserv_path);
 244         }
 245 }
 246
 247 /**
 248  * Core function, assigns label cunks
 249  *
 250  * It first searches through the list to check if there's one available
 251  * (previously released). Otherwise it creates and assigns a new one
 252  *
 253  * @param proto Daemon protocol of client, to identify the owner
 254  * @param instance Instance, to identify the owner
 255  * @param keep If set, avoid garbage collection
 256  * @para size Size of the label chunk
 257  * @return Pointer to the assigned label chunk
 258  */
 259 struct label_manager_chunk *assign_label_chunk(u_char proto, u_short instance,
 260                                                u_char keep, uint32_t size)
 261 {
 262         struct label_manager_chunk *lmc;
 263         struct listnode *node;
 264
 265         /* first check if there's one available */
 266         for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
 267                 if (lmc->proto == NO_PROTO
 268                     && lmc->end - lmc->start + 1 == size) {
 269                         lmc->proto = proto;
 270                         lmc->instance = instance;
 271                         lmc->keep = keep;
 272                         return lmc;
 273                 }
 274         }
 275         /* otherwise create a new one */
 276         lmc = XCALLOC(MTYPE_LM_CHUNK, sizeof(struct label_manager_chunk));
 277         if (!lmc)
 278                 return NULL;
 279
 280         if (list_isempty(lbl_mgr.lc_list))
 281                 lmc->start = MPLS_MIN_UNRESERVED_LABEL;
 282         else
 283                 lmc->start = ((struct label_manager_chunk *)listgetdata(
 284                                       listtail(lbl_mgr.lc_list)))
 285                                      ->end
 286                              + 1;
 287         if (lmc->start > MPLS_MAX_UNRESERVED_LABEL - size + 1) {
 288                 zlog_err("Reached max labels. Start: %u, size: %u", lmc->start,
 289                          size);
 290                 XFREE(MTYPE_LM_CHUNK, lmc);
 291                 return NULL;
 292         }
 293         lmc->end = lmc->start + size - 1;
 294         lmc->proto = proto;
 295         lmc->instance = instance;
 296         lmc->keep = keep;
 297         listnode_add(lbl_mgr.lc_list, lmc);
 298
 299         return lmc;
 300 }
 301
 302 /**
 303  * Core function, release no longer used label cunks
 304  *
 305  * @param proto Daemon protocol of client, to identify the owner
 306  * @param instance Instance, to identify the owner
 307  * @param start First label of the chunk
 308  * @param end Last label of the chunk
 309  * @return 0 on success, -1 otherwise
 310  */
 311 int release_label_chunk(u_char proto, u_short instance, uint32_t start,
 312                         uint32_t end)
 313 {
 314         struct listnode *node;
 315         struct label_manager_chunk *lmc;
 316         int ret = -1;
 317
 318         /* check that size matches */
 319         zlog_debug("Releasing label chunk: %u - %u", start, end);
 320         /* find chunk and disown */
 321         for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
 322                 if (lmc->start != start)
 323                         continue;
 324                 if (lmc->end != end)
 325                         continue;
 326                 if (lmc->proto != proto || lmc->instance != instance) {
 327                         zlog_err("%s: Daemon mismatch!!", __func__);
 328                         continue;
 329                 }
 330                 lmc->proto = NO_PROTO;
 331                 lmc->instance = 0;
 332                 lmc->keep = 0;
 333                 ret = 0;
 334                 break;
 335         }
 336         if (ret != 0)
 337                 zlog_err("%s: Label chunk not released!!", __func__);
 338
 339         return ret;
 340 }
 341
 342 /**
 343  * Release label chunks from a client.
 344  *
 345  * Called on client disconnection or reconnection. It only releases chunks
 346  * with empty keep value.
 347  *
 348  * @param proto Daemon protocol of client, to identify the owner
 349  * @param instance Instance, to identify the owner
 350  * @return Number of chunks released
 351  */
 352 int release_daemon_chunks(u_char proto, u_short instance)
 353 {
 354         struct listnode *node;
 355         struct label_manager_chunk *lmc;
 356         int count = 0;
 357         int ret;
 358
 359         for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
 360                 if (lmc->proto == proto && lmc->instance == instance
 361                     && lmc->keep == 0) {
 362                         ret = release_label_chunk(lmc->proto, lmc->instance,
 363                                                   lmc->start, lmc->end);
 364                         if (ret == 0)
 365                                 count++;
 366                 }
 367         }
 368
 369         zlog_debug("%s: Released %d label chunks", __func__, count);
 370
 371         return count;
 372 }
 373
 374 void label_manager_close()
 375 {
 376         list_delete(lbl_mgr.lc_list);
 377 }