src/resolve/resolved-link.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2014 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <net/if.h>
  23
  24 #include "sd-network.h"
  25 #include "strv.h"
  26 #include "resolved-link.h"
  27
  28 #define DEFAULT_TTL (10)
  29
  30 static void link_address_add_rrs(LinkAddress *a);
  31
  32 int link_new(Manager *m, Link **ret, int ifindex) {
  33         _cleanup_(link_freep) Link *l = NULL;
  34         int r;
  35
  36         assert(m);
  37         assert(ifindex > 0);
  38
  39         r = hashmap_ensure_allocated(&m->links, NULL, NULL);
  40         if (r < 0)
  41                 return r;
  42
  43         l = new0(Link, 1);
  44         if (!l)
  45                 return -ENOMEM;
  46
  47         l->ifindex = ifindex;
  48
  49         r = hashmap_put(m->links, INT_TO_PTR(ifindex), l);
  50         if (r < 0)
  51                 return r;
  52
  53         l->manager = m;
  54
  55         if (ret)
  56                 *ret = l;
  57         l = NULL;
  58
  59         return 0;
  60 }
  61
  62 Link *link_free(Link *l) {
  63
  64         if (!l)
  65                 return NULL;
  66
  67         while (l->addresses)
  68                 link_address_free(l->addresses);
  69
  70         if (l->manager)
  71                 hashmap_remove(l->manager->links, INT_TO_PTR(l->ifindex));
  72
  73         dns_scope_free(l->unicast_scope);
  74         dns_scope_free(l->llmnr_ipv4_scope);
  75         dns_scope_free(l->llmnr_ipv6_scope);
  76
  77         while (l->dns_servers)
  78                 dns_server_free(l->dns_servers);
  79
  80         free(l);
  81         return NULL;
  82 }
  83
  84 static void link_allocate_scopes(Link *l) {
  85         int r;
  86
  87         assert(l);
  88
  89         if (l->dns_servers) {
  90                 if (!l->unicast_scope) {
  91                         r = dns_scope_new(l->manager, &l->unicast_scope, l, DNS_PROTOCOL_DNS, AF_UNSPEC);
  92                         if (r < 0)
  93                                 log_warning("Failed to allocate DNS scope: %s", strerror(-r));
  94                 }
  95         } else
  96                 l->unicast_scope = dns_scope_free(l->unicast_scope);
  97
  98         if (link_relevant(l, AF_INET) && l->manager->use_llmnr) {
  99                 if (!l->llmnr_ipv4_scope) {
 100                         r = dns_scope_new(l->manager, &l->llmnr_ipv4_scope, l, DNS_PROTOCOL_LLMNR, AF_INET);
 101                         if (r < 0)
 102                                 log_warning("Failed to allocate LLMNR IPv4 scope: %s", strerror(-r));
 103                 }
 104         } else
 105                 l->llmnr_ipv4_scope = dns_scope_free(l->llmnr_ipv4_scope);
 106
 107         if (link_relevant(l, AF_INET6) && l->manager->use_llmnr) {
 108                 if (!l->llmnr_ipv6_scope) {
 109                         r = dns_scope_new(l->manager, &l->llmnr_ipv6_scope, l, DNS_PROTOCOL_LLMNR, AF_INET6);
 110                         if (r < 0)
 111                                 log_warning("Failed to allocate LLMNR IPv6 scope: %s", strerror(-r));
 112                 }
 113         } else
 114                 l->llmnr_ipv6_scope = dns_scope_free(l->llmnr_ipv6_scope);
 115 }
 116
 117 static void link_add_rrs(Link *l) {
 118         LinkAddress *a;
 119
 120         LIST_FOREACH(addresses, a, l->addresses)
 121                 link_address_add_rrs(a);
 122 }
 123
 124 int link_update_rtnl(Link *l, sd_rtnl_message *m) {
 125         const char *n = NULL;
 126         int r;
 127
 128         assert(l);
 129         assert(m);
 130
 131         r = sd_rtnl_message_link_get_flags(m, &l->flags);
 132         if (r < 0)
 133                 return r;
 134
 135         sd_rtnl_message_read_u32(m, IFLA_MTU, &l->mtu);
 136
 137         if (sd_rtnl_message_read_string(m, IFLA_IFNAME, &n) >= 0) {
 138                 strncpy(l->name, n, sizeof(l->name));
 139                 char_array_0(l->name);
 140         }
 141
 142         link_allocate_scopes(l);
 143         link_add_rrs(l);
 144
 145         return 0;
 146 }
 147
 148 static int link_update_dns_servers(Link *l) {
 149         _cleanup_strv_free_ char **nameservers = NULL;
 150         char **nameserver;
 151         DnsServer *s, *nx;
 152         int r;
 153
 154         assert(l);
 155
 156         LIST_FOREACH(servers, s, l->dns_servers)
 157                 s->marked = true;
 158
 159         r = sd_network_get_dns(l->ifindex, &nameservers);
 160         if (r < 0)
 161                 goto clear;
 162
 163         STRV_FOREACH(nameserver, nameservers) {
 164                 union in_addr_union a;
 165                 int family;
 166
 167                 r = in_addr_from_string_auto(*nameserver, &family, &a);
 168                 if (r < 0)
 169                         goto clear;
 170
 171                 s = link_find_dns_server(l, family, &a);
 172                 if (s)
 173                         s->marked = false;
 174                 else {
 175                         r = dns_server_new(l->manager, NULL, l, family, &a);
 176                         if (r < 0)
 177                                 goto clear;
 178                 }
 179         }
 180
 181         LIST_FOREACH_SAFE(servers, s, nx, l->dns_servers)
 182                 if (s->marked)
 183                         dns_server_free(s);
 184
 185         return 0;
 186
 187 clear:
 188         while (l->dns_servers)
 189                 dns_server_free(l->dns_servers);
 190
 191         return r;
 192 }
 193
 194 int link_update_monitor(Link *l) {
 195         assert(l);
 196
 197         link_update_dns_servers(l);
 198         link_allocate_scopes(l);
 199         link_add_rrs(l);
 200
 201         return 0;
 202 }
 203
 204 bool link_relevant(Link *l, int family) {
 205         _cleanup_free_ char *state = NULL;
 206         LinkAddress *a;
 207
 208         assert(l);
 209
 210         /* A link is relevant if it isn't a loopback device and has at
 211          * least one relevant IP address */
 212
 213         if (l->flags & IFF_LOOPBACK)
 214                 return false;
 215
 216         sd_network_get_link_operational_state(l->ifindex, &state);
 217         if (state && !STR_IN_SET(state, "unknown", "degraded", "routable"))
 218                 return false;
 219
 220         LIST_FOREACH(addresses, a, l->addresses)
 221                 if (a->family == family && link_address_relevant(a))
 222                         return true;
 223
 224         return false;
 225 }
 226
 227 LinkAddress *link_find_address(Link *l, int family, const union in_addr_union *in_addr) {
 228         LinkAddress *a;
 229
 230         assert(l);
 231
 232         LIST_FOREACH(addresses, a, l->addresses)
 233                 if (a->family == family && in_addr_equal(family, &a->in_addr, in_addr))
 234                         return a;
 235
 236         return NULL;
 237 }
 238
 239 DnsServer* link_find_dns_server(Link *l, int family, const union in_addr_union *in_addr) {
 240         DnsServer *s;
 241
 242         assert(l);
 243
 244         LIST_FOREACH(servers, s, l->dns_servers)
 245                 if (s->family == family && in_addr_equal(family, &s->address, in_addr))
 246                         return s;
 247         return NULL;
 248 }
 249
 250 DnsServer *link_get_dns_server(Link *l) {
 251         assert(l);
 252
 253         if (!l->current_dns_server)
 254                 l->current_dns_server = l->dns_servers;
 255
 256         return l->current_dns_server;
 257 }
 258
 259 void link_next_dns_server(Link *l) {
 260         assert(l);
 261
 262         /* Switch to the next DNS server */
 263
 264         if (!l->current_dns_server) {
 265                 l->current_dns_server = l->dns_servers;
 266                 if (l->current_dns_server)
 267                         return;
 268         }
 269
 270         if (!l->current_dns_server)
 271                 return;
 272
 273         if (l->current_dns_server->servers_next) {
 274                 l->current_dns_server = l->current_dns_server->servers_next;
 275                 return;
 276         }
 277
 278         l->current_dns_server = l->dns_servers;
 279 }
 280
 281 int link_address_new(Link *l, LinkAddress **ret, int family, const union in_addr_union *in_addr) {
 282         LinkAddress *a;
 283
 284         assert(l);
 285         assert(in_addr);
 286
 287         a = new0(LinkAddress, 1);
 288         if (!a)
 289                 return -ENOMEM;
 290
 291         a->family = family;
 292         a->in_addr = *in_addr;
 293
 294         a->link = l;
 295         LIST_PREPEND(addresses, l->addresses, a);
 296
 297         if (ret)
 298                 *ret = a;
 299
 300         return 0;
 301 }
 302
 303 LinkAddress *link_address_free(LinkAddress *a) {
 304         if (!a)
 305                 return NULL;
 306
 307         if (a->link) {
 308                 LIST_REMOVE(addresses, a->link->addresses, a);
 309
 310                 if (a->llmnr_address_rr) {
 311
 312                         if (a->family == AF_INET && a->link->llmnr_ipv4_scope)
 313                                 dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr);
 314                         else if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope)
 315                                 dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr);
 316
 317                         dns_resource_record_unref(a->llmnr_address_rr);
 318                 }
 319
 320                 if (a->llmnr_ptr_rr) {
 321                         if (a->family == AF_INET && a->link->llmnr_ipv4_scope)
 322                                 dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr);
 323                         else if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope)
 324                                 dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr);
 325
 326                         dns_resource_record_unref(a->llmnr_ptr_rr);
 327                 }
 328         }
 329
 330         free(a);
 331         return NULL;
 332 }
 333
 334 static void link_address_add_rrs(LinkAddress *a) {
 335         int r;
 336
 337         assert(a);
 338
 339         if (a->family == AF_INET && a->link->llmnr_ipv4_scope) {
 340
 341                 if (!a->link->manager->host_ipv4_key) {
 342                         a->link->manager->host_ipv4_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, a->link->manager->hostname);
 343                         if (!a->link->manager->host_ipv4_key) {
 344                                 r = -ENOMEM;
 345                                 goto fail;
 346                         }
 347                 }
 348
 349                 if (!a->llmnr_address_rr) {
 350                         a->llmnr_address_rr = dns_resource_record_new(a->link->manager->host_ipv4_key);
 351                         if (!a->llmnr_address_rr) {
 352                                 r = -ENOMEM;
 353                                 goto fail;
 354                         }
 355
 356                         a->llmnr_address_rr->a.in_addr = a->in_addr.in;
 357                         a->llmnr_address_rr->ttl = DEFAULT_TTL;
 358                 }
 359
 360                 if (!a->llmnr_ptr_rr) {
 361                         r = dns_resource_record_new_reverse(&a->llmnr_ptr_rr, a->family, &a->in_addr, a->link->manager->hostname);
 362                         if (r < 0)
 363                                 goto fail;
 364
 365                         a->llmnr_ptr_rr->ttl = DEFAULT_TTL;
 366                 }
 367
 368                 if (link_address_relevant(a)) {
 369                         r = dns_zone_put(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr);
 370                         if (r < 0)
 371                                 goto fail;
 372
 373                         r = dns_zone_put(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr);
 374                         if (r < 0)
 375                                 goto fail;
 376                 } else {
 377                         dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr);
 378                         dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr);
 379                 }
 380         }
 381
 382         if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope) {
 383
 384                 if (!a->link->manager->host_ipv6_key) {
 385                         a->link->manager->host_ipv6_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_AAAA, a->link->manager->hostname);
 386                         if (!a->link->manager->host_ipv6_key) {
 387                                 r = -ENOMEM;
 388                                 goto fail;
 389                         }
 390                 }
 391
 392                 if (!a->llmnr_address_rr) {
 393                         a->llmnr_address_rr = dns_resource_record_new(a->link->manager->host_ipv6_key);
 394                         if (!a->llmnr_address_rr) {
 395                                 r = -ENOMEM;
 396                                 goto fail;
 397                         }
 398
 399                         a->llmnr_address_rr->aaaa.in6_addr = a->in_addr.in6;
 400                         a->llmnr_address_rr->ttl = DEFAULT_TTL;
 401                 }
 402
 403                 if (!a->llmnr_ptr_rr) {
 404                         r = dns_resource_record_new_reverse(&a->llmnr_ptr_rr, a->family, &a->in_addr, a->link->manager->hostname);
 405                         if (r < 0)
 406                                 goto fail;
 407
 408                         a->llmnr_ptr_rr->ttl = DEFAULT_TTL;
 409                 }
 410
 411                 if (link_address_relevant(a)) {
 412                         r = dns_zone_put(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr);
 413                         if (r < 0)
 414                                 goto fail;
 415
 416                         r = dns_zone_put(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr);
 417                         if (r < 0)
 418                                 goto fail;
 419                 } else {
 420                         dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr);
 421                         dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr);
 422                 }
 423         }
 424
 425         return;
 426
 427 fail:
 428         log_debug("Failed to update address RRs: %s", strerror(-r));
 429 }
 430
 431 int link_address_update_rtnl(LinkAddress *a, sd_rtnl_message *m) {
 432         int r;
 433         assert(a);
 434         assert(m);
 435
 436         r = sd_rtnl_message_addr_get_flags(m, &a->flags);
 437         if (r < 0)
 438                 return r;
 439
 440         sd_rtnl_message_addr_get_scope(m, &a->scope);
 441
 442         link_allocate_scopes(a->link);
 443         link_add_rrs(a->link);
 444
 445         return 0;
 446 }
 447
 448 bool link_address_relevant(LinkAddress *a) {
 449         assert(a);
 450
 451         if (a->flags & IFA_F_DEPRECATED)
 452                 return false;
 453
 454         if (IN_SET(a->scope, RT_SCOPE_HOST, RT_SCOPE_NOWHERE))
 455                 return false;
 456
 457         return true;
 458 }