src/networkd/link.c

   1 /*#############################################################################
   2 #                                                                             #
   3 # IPFire.org - A linux based firewall                                         #
   4 # Copyright (C) 2023 IPFire Network Development Team                          #
   5 #                                                                             #
   6 # This program is free software: you can redistribute it and/or modify        #
   7 # it under the terms of the GNU General Public License as published by        #
   8 # the Free Software Foundation, either version 3 of the License, or           #
   9 # (at your option) any later version.                                         #
  10 #                                                                             #
  11 # This program is distributed in the hope that it will be useful,             #
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of              #
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
  14 # GNU General Public License for more details.                                #
  15 #                                                                             #
  16 # You should have received a copy of the GNU General Public License           #
  17 # along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
  18 #                                                                             #
  19 #############################################################################*/
  20
  21 #include <linux/if.h>
  22 #include <linux/if_link.h>
  23 #include <stddef.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include <systemd/sd-netlink.h>
  28
  29 #include "daemon.h"
  30 #include "link.h"
  31 #include "links.h"
  32 #include "logging.h"
  33 #include "string.h"
  34
  35 struct nw_link {
  36         nw_daemon* daemon;
  37         int nrefs;
  38
  39         // Interface Index
  40         int ifindex;
  41
  42         // Interface Name
  43         char ifname[IFNAMSIZ];
  44
  45         enum nw_link_state {
  46                 NW_LINK_UNKNOWN = 0,
  47                 NW_LINK_DESTROYED,
  48         } state;
  49
  50         // Stats
  51         struct rtnl_link_stats64 stats64;
  52
  53         // MTU
  54         uint32_t mtu;
  55         uint32_t min_mtu;
  56         uint32_t max_mtu;
  57
  58         // Flags
  59         unsigned int flags;
  60         uint8_t operstate;
  61 };
  62
  63 int nw_link_create(nw_link** link, nw_daemon* daemon, int ifindex) {
  64         // Allocate a new object
  65         nw_link* l = calloc(1, sizeof(*l));
  66         if (!l)
  67                 return 1;
  68
  69         // Store a reference to the daemon
  70         l->daemon = nw_daemon_ref(daemon);
  71
  72         // Initialize the reference counter
  73         l->nrefs = 1;
  74
  75         // Store the ifindex
  76         l->ifindex = ifindex;
  77
  78         DEBUG("New link allocated (ifindex = %d)\n", l->ifindex);
  79
  80         *link = l;
  81
  82         return 0;
  83 }
  84
  85 static void nw_link_free(nw_link* link) {
  86         DEBUG("Freeing link (ifindex = %d)\n", link->ifindex);
  87
  88         if (link->daemon)
  89                 nw_daemon_unref(link->daemon);
  90 }
  91
  92 nw_link* nw_link_ref(nw_link* link) {
  93         link->nrefs++;
  94
  95         return link;
  96 }
  97
  98 nw_link* nw_link_unref(nw_link* link) {
  99         if (--link->nrefs > 0)
 100                 return link;
 101
 102         nw_link_free(link);
 103         return NULL;
 104 }
 105
 106 /*
 107         This is a helper function for when we pass a reference to the event loop
 108         it will have to dereference the link instance later.
 109 */
 110 static void __nw_link_unref(void* data) {
 111         nw_link* link = (nw_link*)data;
 112
 113         nw_link_unref(link);
 114 }
 115
 116 int nw_link_ifindex(nw_link* link) {
 117         return link->ifindex;
 118 }
 119
 120 const char* nw_link_ifname(nw_link* link) {
 121         // Return NULL if name isn't set
 122         if (!*link->ifname)
 123                 return NULL;
 124
 125         return link->ifname;
 126 }
 127
 128 // Stats
 129
 130 const struct rtnl_link_stats64* nw_link_get_stats64(nw_link* link) {
 131         return &link->stats64;
 132 }
 133
 134 static int nw_link_call_getlink(nw_link* link,
 135                 int (*callback)(sd_netlink* rtnl, sd_netlink_message* m, void* data)) {
 136         sd_netlink_message* m = NULL;
 137         int r;
 138
 139         sd_netlink* rtnl = nw_daemon_get_rtnl(link->daemon);
 140         if (!rtnl)
 141                 return 1;
 142
 143         // Create a new message
 144         r = sd_rtnl_message_new_link(rtnl, &m, RTM_GETLINK, link->ifindex);
 145         if (r < 0) {
 146                 ERROR("Could not allocate RTM_GETLINK message: %m\n");
 147                 goto ERROR;
 148         }
 149
 150         // Send the message
 151         r = sd_netlink_call_async(rtnl, NULL, m, callback,
 152                 __nw_link_unref, nw_link_ref(link), -1, NULL);
 153         if (r < 0) {
 154                 ERROR("Could not send rtnetlink message: %m\n");
 155                 goto ERROR;
 156         }
 157
 158 ERROR:
 159         if (m)
 160                 sd_netlink_message_unref(m);
 161
 162         return r;
 163 }
 164
 165 static int __nw_link_update_stats(sd_netlink* rtnl, sd_netlink_message* m, void* data) {
 166         nw_link* link = (nw_link*)data;
 167         int r;
 168
 169         // Fetch the stats
 170         r = sd_netlink_message_read(m, IFLA_STATS64, sizeof(link->stats64), &link->stats64);
 171         if (r < 0)
 172                 return r;
 173
 174         DEBUG("Link %d: Stats updated\n", link->ifindex);
 175
 176         // Log stats
 177         DEBUG("  Packets    : RX: %12llu, TX: %12llu\n",
 178                 link->stats64.rx_packets, link->stats64.tx_packets);
 179         DEBUG("  Bytes      : RX: %12llu, TX: %12llu\n",
 180                 link->stats64.rx_bytes,   link->stats64.tx_bytes);
 181         DEBUG("  Errors     : RX: %12llu, TX: %12llu\n",
 182                 link->stats64.rx_errors,  link->stats64.tx_errors);
 183         DEBUG("  Dropped    : RX: %12llu, TX: %12llu\n",
 184                 link->stats64.rx_dropped, link->stats64.rx_dropped);
 185         DEBUG("  Multicast  : %llu\n", link->stats64.multicast);
 186         DEBUG("  Collisions : %llu\n", link->stats64.collisions);
 187
 188         // Notify ports that stats have been updated
 189         r = nw_daemon_ports_walk(link->daemon, __nw_port_update_stats, link);
 190         if (r)
 191                 return r;
 192
 193         // Notify zones that stats have been updated
 194         r = nw_daemon_zones_walk(link->daemon, __nw_zone_update_stats, link);
 195         if (r)
 196                 return r;
 197
 198         return 0;
 199 }
 200
 201 int nw_link_update_stats(nw_link* link) {
 202         return nw_link_call_getlink(link, __nw_link_update_stats);
 203 }
 204
 205 // Carrier
 206
 207 int nw_link_has_carrier(nw_link* link) {
 208         return link->operstate == IF_OPER_UP;
 209 }
 210
 211 static int nw_link_carrier_gained(nw_link* link) {
 212         return 0; // XXX TODO
 213 }
 214
 215 static int nw_link_carrier_lost(nw_link* link) {
 216         return 0; // XXX TODO
 217 }
 218
 219 static int nw_link_update_ifname(nw_link* link, sd_netlink_message* message) {
 220         const char* ifname = NULL;
 221         int r;
 222
 223         r = sd_netlink_message_read_string(message, IFLA_IFNAME, &ifname);
 224         if (r < 0) {
 225                 ERROR("Could not read link name for link %d: %m\n", link->ifindex);
 226                 return 1;
 227         }
 228
 229         // Do nothing if the name is already set
 230         if (strcmp(link->ifname, ifname) == 0)
 231                 return 0;
 232
 233         // Otherwise update the name
 234         r = nw_string_set(link->ifname, ifname);
 235         if (r) {
 236                 ERROR("Could not set link name: %m\n");
 237                 return 1;
 238         }
 239
 240         DEBUG("Link %d has been renamed to '%s'\n", link->ifindex, link->ifname);
 241
 242         // Assign link to ports
 243         nw_daemon_ports_walk(link->daemon, __nw_port_set_link, link);
 244
 245         // Assign link to zones
 246         nw_daemon_zones_walk(link->daemon, __nw_zone_set_link, link);
 247
 248         return 0;
 249 }
 250
 251 static int nw_link_update_mtu(nw_link* link, sd_netlink_message* message) {
 252         uint32_t mtu = 0;
 253         uint32_t min_mtu = 0;
 254         uint32_t max_mtu = 0;
 255         int r;
 256
 257         // Read the MTU
 258         r = sd_netlink_message_read_u32(message, IFLA_MTU, &mtu);
 259         if (r < 0) {
 260                 ERROR("Could not read MTU for link %d: %m\n", link->ifindex);
 261                 return r;
 262         }
 263
 264         // Read the minimum MTU
 265         r = sd_netlink_message_read_u32(message, IFLA_MIN_MTU, &min_mtu);
 266         if (r < 0) {
 267                 ERROR("Could not read the minimum MTU for link %d: %m\n", link->ifindex);
 268                 return r;
 269         }
 270
 271         // Read the maximum MTU
 272         r = sd_netlink_message_read_u32(message, IFLA_MAX_MTU, &max_mtu);
 273         if (r < 0) {
 274                 ERROR("Could not read the maximum MTU for link %d: %m\n", link->ifindex);
 275                 return r;
 276         }
 277
 278         // Set the maximum MTU to infinity
 279         if (!max_mtu)
 280                 max_mtu = UINT32_MAX;
 281
 282         // Store min/max MTU
 283         link->min_mtu = min_mtu;
 284         link->max_mtu = max_mtu;
 285
 286         // End here, if the MTU has not been changed
 287         if (link->mtu == mtu)
 288                 return 0;
 289
 290         DEBUG("Link %d: MTU has changed to %" PRIu32 " (min: %" PRIu32 ", max: %" PRIu32 ")\n",
 291                 link->ifindex, link->mtu, link->min_mtu, link->max_mtu);
 292
 293         // Store MTU
 294         link->mtu = mtu;
 295
 296         return 0;
 297 }
 298
 299 static int nw_link_update_flags(nw_link* link, sd_netlink_message* message) {
 300         unsigned int flags = 0;
 301         uint8_t operstate = 0;
 302         int r;
 303
 304         // Fetch flags
 305         r = sd_rtnl_message_link_get_flags(message, &flags);
 306         if (r < 0) {
 307                 DEBUG("Could not read link flags: %m\n");
 308                 return 1;
 309         }
 310
 311         // Fetch operstate
 312         r = sd_netlink_message_read_u8(message, IFLA_OPERSTATE, &operstate);
 313         if (r < 1) {
 314                 ERROR("Could not read operstate: %m\n");
 315                 return 1;
 316         }
 317
 318         // End here if there have been no changes
 319         if (link->flags == flags && link->operstate == operstate)
 320                 return 0;
 321
 322         // XXX We should log any changes here
 323
 324         // Fetch current carrier state
 325         const int had_carrier = nw_link_has_carrier(link);
 326
 327         // Store the new flags & operstate
 328         link->flags = flags;
 329         link->operstate = operstate;
 330
 331         // Notify if carrier was gained or lost
 332         if (!had_carrier && nw_link_has_carrier(link)) {
 333                 r = nw_link_carrier_gained(link);
 334                 if (r < 0)
 335                         return r;
 336
 337         } else if (had_carrier && !nw_link_has_carrier(link)) {
 338                 r = nw_link_carrier_lost(link);
 339                 if (r < 0)
 340                         return r;
 341         }
 342
 343         return 0;
 344 }
 345
 346 /*
 347         This function is called whenever anything changes, so that we can
 348         update our internal link object.
 349 */
 350 static int nw_link_update(nw_link* link, sd_netlink_message* message) {
 351         int r;
 352
 353         // Update the interface name
 354         r = nw_link_update_ifname(link, message);
 355         if (r)
 356                 return r;
 357
 358         // Update the MTU
 359         r = nw_link_update_mtu(link, message);
 360         if (r)
 361                 return r;
 362
 363         // Update flags
 364         r = nw_link_update_flags(link, message);
 365         if (r)
 366                 return r;
 367
 368         return 0;
 369 }
 370
 371 int nw_link_process(sd_netlink* rtnl, sd_netlink_message* message, void* data) {
 372         nw_links* links = NULL;
 373         nw_link* link = NULL;
 374         const char* ifname = NULL;
 375         int ifindex;
 376         uint16_t type;
 377         int r;
 378
 379         nw_daemon* daemon = (nw_daemon*)data;
 380
 381         // Fetch links
 382         links = nw_daemon_links(daemon);
 383         if (!links) {
 384                 r = 1;
 385                 goto ERROR;
 386         }
 387
 388         // Check if this message could be received
 389         if (sd_netlink_message_is_error(message)) {
 390                 r = sd_netlink_message_get_errno(message);
 391                 if (r < 0)
 392                         ERROR("Could not receive link message: %m\n");
 393
 394                 goto IGNORE;
 395         }
 396
 397         // Fetch the message type
 398         r = sd_netlink_message_get_type(message, &type);
 399         if (r < 0) {
 400                 ERROR("Could not fetch message type: %m\n");
 401                 goto IGNORE;
 402         }
 403
 404         // Check type
 405         switch (type) {
 406                 case RTM_NEWLINK:
 407                 case RTM_DELLINK:
 408                         break;
 409
 410                 default:
 411                         ERROR("Received an unexpected message (type %u)\n", type);
 412                         goto IGNORE;
 413         }
 414
 415         // Fetch the interface index
 416         r = sd_rtnl_message_link_get_ifindex(message, &ifindex);
 417         if (r < 0) {
 418                 ERROR("Could not fetch ifindex: %m\n");
 419                 goto IGNORE;
 420         }
 421
 422         // Check interface index
 423         if (ifindex <= 0) {
 424                 ERROR("Received an invalid ifindex\n");
 425                 goto IGNORE;
 426         }
 427
 428         // Fetch the interface name
 429         r = sd_netlink_message_read_string(message, IFLA_IFNAME, &ifname);
 430         if (r < 0) {
 431                 ERROR("Received a netlink message without interface name: %m\n");
 432                 goto IGNORE;
 433         }
 434
 435         // Try finding an existing link
 436         link = nw_daemon_get_link_by_ifindex(daemon, ifindex);
 437
 438         switch (type) {
 439                 case RTM_NEWLINK:
 440                         // If the link doesn't exist, create it
 441                         if (!link) {
 442                                 r = nw_link_create(&link, daemon, ifindex);
 443                                 if (r) {
 444                                         ERROR("Could not create link: %m\n");
 445                                         goto ERROR;
 446                                 }
 447
 448                                 // Add it to the list
 449                                 r = nw_links_add_link(links, link);
 450                                 if (r)
 451                                         goto ERROR;
 452                         }
 453
 454                         // Import any data from the netlink message
 455                         r = nw_link_update(link, message);
 456                         if (r)
 457                                 goto ERROR;
 458
 459                         break;
 460
 461                 case RTM_DELLINK:
 462                         if (link)
 463                                 nw_links_drop_link(links, link);
 464
 465                         break;
 466         }
 467
 468 IGNORE:
 469         r = 0;
 470
 471 ERROR:
 472         if (links)
 473                 nw_links_unref(links);
 474         if (link)
 475                 nw_link_unref(link);
 476
 477         return r;
 478 }
 479
 480 static int __nw_link_destroy(sd_netlink* rtnl, sd_netlink_message* m, void* data) {
 481         nw_link* link = (nw_link*)data;
 482         int r;
 483
 484         // Check if the operation was successful
 485         r = sd_netlink_message_get_errno(m);
 486         if (r < 0) {
 487                 ERROR("Could not remove link %d: %m\n", link->ifindex);
 488                 // XXX We should extract the error message
 489
 490                 return 0;
 491         }
 492
 493         // Mark this link as destroyed
 494         link->state = NW_LINK_DESTROYED;
 495
 496         return 0;
 497 }
 498
 499 int nw_link_destroy(nw_link* link) {
 500         sd_netlink_message* m = NULL;
 501         int r;
 502
 503         sd_netlink* rtnl = nw_daemon_get_rtnl(link->daemon);
 504         if (!rtnl)
 505                 return 1;
 506
 507         DEBUG("Destroying link %d\n", link->ifindex);
 508
 509         // Create a new message
 510         r = sd_rtnl_message_new_link(rtnl, &m, RTM_DELLINK, link->ifindex);
 511         if (r < 0) {
 512                 ERROR("Could not allocate RTM_DELLINK message: %m\n");
 513                 goto ERROR;
 514         }
 515
 516         // Send the message
 517         r = sd_netlink_call_async(rtnl, NULL, m, __nw_link_destroy,
 518                 __nw_link_unref, nw_link_ref(link), -1, NULL);
 519         if (r < 0) {
 520                 ERROR("Could not send rtnetlink message: %m\n");
 521                 goto ERROR;
 522         }
 523
 524 ERROR:
 525         if (m)
 526                 sd_netlink_message_unref(m);
 527
 528         return r;
 529 }