src/basic/socket-util.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <arpa/inet.h>
  21 #include <errno.h>
  22 #include <limits.h>
  23 #include <net/if.h>
  24 #include <netdb.h>
  25 #include <netinet/ip.h>
  26 #include <poll.h>
  27 #include <stddef.h>
  28 #include <stdint.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <unistd.h>
  33
  34 #include "alloc-util.h"
  35 #include "fd-util.h"
  36 #include "fileio.h"
  37 #include "format-util.h"
  38 #include "log.h"
  39 #include "macro.h"
  40 #include "missing.h"
  41 #include "parse-util.h"
  42 #include "path-util.h"
  43 #include "socket-util.h"
  44 #include "string-table.h"
  45 #include "string-util.h"
  46 #include "strv.h"
  47 #include "user-util.h"
  48 #include "utf8.h"
  49 #include "util.h"
  50
  51 #if ENABLE_IDN
  52 #  define IDN_FLAGS (NI_IDN|NI_IDN_USE_STD3_ASCII_RULES)
  53 #else
  54 #  define IDN_FLAGS 0
  55 #endif
  56
  57 int socket_address_parse(SocketAddress *a, const char *s) {
  58         char *e, *n;
  59         unsigned u;
  60         int r;
  61
  62         assert(a);
  63         assert(s);
  64
  65         zero(*a);
  66         a->type = SOCK_STREAM;
  67
  68         if (*s == '[') {
  69                 /* IPv6 in [x:.....:z]:p notation */
  70
  71                 e = strchr(s+1, ']');
  72                 if (!e)
  73                         return -EINVAL;
  74
  75                 n = strndupa(s+1, e-s-1);
  76
  77                 errno = 0;
  78                 if (inet_pton(AF_INET6, n, &a->sockaddr.in6.sin6_addr) <= 0)
  79                         return errno > 0 ? -errno : -EINVAL;
  80
  81                 e++;
  82                 if (*e != ':')
  83                         return -EINVAL;
  84
  85                 e++;
  86                 r = safe_atou(e, &u);
  87                 if (r < 0)
  88                         return r;
  89
  90                 if (u <= 0 || u > 0xFFFF)
  91                         return -EINVAL;
  92
  93                 a->sockaddr.in6.sin6_family = AF_INET6;
  94                 a->sockaddr.in6.sin6_port = htobe16((uint16_t)u);
  95                 a->size = sizeof(struct sockaddr_in6);
  96
  97         } else if (*s == '/') {
  98                 /* AF_UNIX socket */
  99
 100                 size_t l;
 101
 102                 l = strlen(s);
 103                 if (l >= sizeof(a->sockaddr.un.sun_path))
 104                         return -EINVAL;
 105
 106                 a->sockaddr.un.sun_family = AF_UNIX;
 107                 memcpy(a->sockaddr.un.sun_path, s, l);
 108                 a->size = offsetof(struct sockaddr_un, sun_path) + l + 1;
 109
 110         } else if (*s == '@') {
 111                 /* Abstract AF_UNIX socket */
 112                 size_t l;
 113
 114                 l = strlen(s+1);
 115                 if (l >= sizeof(a->sockaddr.un.sun_path) - 1)
 116                         return -EINVAL;
 117
 118                 a->sockaddr.un.sun_family = AF_UNIX;
 119                 memcpy(a->sockaddr.un.sun_path+1, s+1, l);
 120                 a->size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
 121
 122         } else if (startswith(s, "vsock:")) {
 123                 /* AF_VSOCK socket in vsock:cid:port notation */
 124                 const char *cid_start = s + strlen("vsock:");
 125
 126                 e = strchr(cid_start, ':');
 127                 if (!e)
 128                         return -EINVAL;
 129
 130                 r = safe_atou(e+1, &u);
 131                 if (r < 0)
 132                         return r;
 133
 134                 n = strndupa(cid_start, e - cid_start);
 135                 if (!isempty(n)) {
 136                         r = safe_atou(n, &a->sockaddr.vm.svm_cid);
 137                         if (r < 0)
 138                                 return r;
 139                 } else
 140                         a->sockaddr.vm.svm_cid = VMADDR_CID_ANY;
 141
 142                 a->sockaddr.vm.svm_family = AF_VSOCK;
 143                 a->sockaddr.vm.svm_port = u;
 144                 a->size = sizeof(struct sockaddr_vm);
 145
 146         } else {
 147                 e = strchr(s, ':');
 148                 if (e) {
 149                         r = safe_atou(e+1, &u);
 150                         if (r < 0)
 151                                 return r;
 152
 153                         if (u <= 0 || u > 0xFFFF)
 154                                 return -EINVAL;
 155
 156                         n = strndupa(s, e-s);
 157
 158                         /* IPv4 in w.x.y.z:p notation? */
 159                         r = inet_pton(AF_INET, n, &a->sockaddr.in.sin_addr);
 160                         if (r < 0)
 161                                 return -errno;
 162
 163                         if (r > 0) {
 164                                 /* Gotcha, it's a traditional IPv4 address */
 165                                 a->sockaddr.in.sin_family = AF_INET;
 166                                 a->sockaddr.in.sin_port = htobe16((uint16_t)u);
 167                                 a->size = sizeof(struct sockaddr_in);
 168                         } else {
 169                                 unsigned idx;
 170
 171                                 if (strlen(n) > IF_NAMESIZE-1)
 172                                         return -EINVAL;
 173
 174                                 /* Uh, our last resort, an interface name */
 175                                 idx = if_nametoindex(n);
 176                                 if (idx == 0)
 177                                         return -EINVAL;
 178
 179                                 a->sockaddr.in6.sin6_family = AF_INET6;
 180                                 a->sockaddr.in6.sin6_port = htobe16((uint16_t)u);
 181                                 a->sockaddr.in6.sin6_scope_id = idx;
 182                                 a->sockaddr.in6.sin6_addr = in6addr_any;
 183                                 a->size = sizeof(struct sockaddr_in6);
 184                         }
 185                 } else {
 186
 187                         /* Just a port */
 188                         r = safe_atou(s, &u);
 189                         if (r < 0)
 190                                 return r;
 191
 192                         if (u <= 0 || u > 0xFFFF)
 193                                 return -EINVAL;
 194
 195                         if (socket_ipv6_is_supported()) {
 196                                 a->sockaddr.in6.sin6_family = AF_INET6;
 197                                 a->sockaddr.in6.sin6_port = htobe16((uint16_t)u);
 198                                 a->sockaddr.in6.sin6_addr = in6addr_any;
 199                                 a->size = sizeof(struct sockaddr_in6);
 200                         } else {
 201                                 a->sockaddr.in.sin_family = AF_INET;
 202                                 a->sockaddr.in.sin_port = htobe16((uint16_t)u);
 203                                 a->sockaddr.in.sin_addr.s_addr = INADDR_ANY;
 204                                 a->size = sizeof(struct sockaddr_in);
 205                         }
 206                 }
 207         }
 208
 209         return 0;
 210 }
 211
 212 int socket_address_parse_and_warn(SocketAddress *a, const char *s) {
 213         SocketAddress b;
 214         int r;
 215
 216         /* Similar to socket_address_parse() but warns for IPv6 sockets when we don't support them. */
 217
 218         r = socket_address_parse(&b, s);
 219         if (r < 0)
 220                 return r;
 221
 222         if (!socket_ipv6_is_supported() && b.sockaddr.sa.sa_family == AF_INET6) {
 223                 log_warning("Binding to IPv6 address not available since kernel does not support IPv6.");
 224                 return -EAFNOSUPPORT;
 225         }
 226
 227         *a = b;
 228         return 0;
 229 }
 230
 231 int socket_address_parse_netlink(SocketAddress *a, const char *s) {
 232         int family;
 233         unsigned group = 0;
 234         _cleanup_free_ char *sfamily = NULL;
 235         assert(a);
 236         assert(s);
 237
 238         zero(*a);
 239         a->type = SOCK_RAW;
 240
 241         errno = 0;
 242         if (sscanf(s, "%ms %u", &sfamily, &group) < 1)
 243                 return errno > 0 ? -errno : -EINVAL;
 244
 245         family = netlink_family_from_string(sfamily);
 246         if (family < 0)
 247                 return -EINVAL;
 248
 249         a->sockaddr.nl.nl_family = AF_NETLINK;
 250         a->sockaddr.nl.nl_groups = group;
 251
 252         a->type = SOCK_RAW;
 253         a->size = sizeof(struct sockaddr_nl);
 254         a->protocol = family;
 255
 256         return 0;
 257 }
 258
 259 int socket_address_verify(const SocketAddress *a) {
 260         assert(a);
 261
 262         switch (socket_address_family(a)) {
 263
 264         case AF_INET:
 265                 if (a->size != sizeof(struct sockaddr_in))
 266                         return -EINVAL;
 267
 268                 if (a->sockaddr.in.sin_port == 0)
 269                         return -EINVAL;
 270
 271                 if (!IN_SET(a->type, SOCK_STREAM, SOCK_DGRAM))
 272                         return -EINVAL;
 273
 274                 return 0;
 275
 276         case AF_INET6:
 277                 if (a->size != sizeof(struct sockaddr_in6))
 278                         return -EINVAL;
 279
 280                 if (a->sockaddr.in6.sin6_port == 0)
 281                         return -EINVAL;
 282
 283                 if (!IN_SET(a->type, SOCK_STREAM, SOCK_DGRAM))
 284                         return -EINVAL;
 285
 286                 return 0;
 287
 288         case AF_UNIX:
 289                 if (a->size < offsetof(struct sockaddr_un, sun_path))
 290                         return -EINVAL;
 291
 292                 if (a->size > offsetof(struct sockaddr_un, sun_path)) {
 293
 294                         if (a->sockaddr.un.sun_path[0] != 0) {
 295                                 char *e;
 296
 297                                 /* path */
 298                                 e = memchr(a->sockaddr.un.sun_path, 0, sizeof(a->sockaddr.un.sun_path));
 299                                 if (!e)
 300                                         return -EINVAL;
 301
 302                                 if (a->size != offsetof(struct sockaddr_un, sun_path) + (e - a->sockaddr.un.sun_path) + 1)
 303                                         return -EINVAL;
 304                         }
 305                 }
 306
 307                 if (!IN_SET(a->type, SOCK_STREAM, SOCK_DGRAM, SOCK_SEQPACKET))
 308                         return -EINVAL;
 309
 310                 return 0;
 311
 312         case AF_NETLINK:
 313
 314                 if (a->size != sizeof(struct sockaddr_nl))
 315                         return -EINVAL;
 316
 317                 if (!IN_SET(a->type, SOCK_RAW, SOCK_DGRAM))
 318                         return -EINVAL;
 319
 320                 return 0;
 321
 322         case AF_VSOCK:
 323                 if (a->size != sizeof(struct sockaddr_vm))
 324                         return -EINVAL;
 325
 326                 if (!IN_SET(a->type, SOCK_STREAM, SOCK_DGRAM))
 327                         return -EINVAL;
 328
 329                 return 0;
 330
 331         default:
 332                 return -EAFNOSUPPORT;
 333         }
 334 }
 335
 336 int socket_address_print(const SocketAddress *a, char **ret) {
 337         int r;
 338
 339         assert(a);
 340         assert(ret);
 341
 342         r = socket_address_verify(a);
 343         if (r < 0)
 344                 return r;
 345
 346         if (socket_address_family(a) == AF_NETLINK) {
 347                 _cleanup_free_ char *sfamily = NULL;
 348
 349                 r = netlink_family_to_string_alloc(a->protocol, &sfamily);
 350                 if (r < 0)
 351                         return r;
 352
 353                 r = asprintf(ret, "%s %u", sfamily, a->sockaddr.nl.nl_groups);
 354                 if (r < 0)
 355                         return -ENOMEM;
 356
 357                 return 0;
 358         }
 359
 360         return sockaddr_pretty(&a->sockaddr.sa, a->size, false, true, ret);
 361 }
 362
 363 bool socket_address_can_accept(const SocketAddress *a) {
 364         assert(a);
 365
 366         return
 367                 IN_SET(a->type, SOCK_STREAM, SOCK_SEQPACKET);
 368 }
 369
 370 bool socket_address_equal(const SocketAddress *a, const SocketAddress *b) {
 371         assert(a);
 372         assert(b);
 373
 374         /* Invalid addresses are unequal to all */
 375         if (socket_address_verify(a) < 0 ||
 376             socket_address_verify(b) < 0)
 377                 return false;
 378
 379         if (a->type != b->type)
 380                 return false;
 381
 382         if (socket_address_family(a) != socket_address_family(b))
 383                 return false;
 384
 385         switch (socket_address_family(a)) {
 386
 387         case AF_INET:
 388                 if (a->sockaddr.in.sin_addr.s_addr != b->sockaddr.in.sin_addr.s_addr)
 389                         return false;
 390
 391                 if (a->sockaddr.in.sin_port != b->sockaddr.in.sin_port)
 392                         return false;
 393
 394                 break;
 395
 396         case AF_INET6:
 397                 if (memcmp(&a->sockaddr.in6.sin6_addr, &b->sockaddr.in6.sin6_addr, sizeof(a->sockaddr.in6.sin6_addr)) != 0)
 398                         return false;
 399
 400                 if (a->sockaddr.in6.sin6_port != b->sockaddr.in6.sin6_port)
 401                         return false;
 402
 403                 break;
 404
 405         case AF_UNIX:
 406                 if (a->size <= offsetof(struct sockaddr_un, sun_path) ||
 407                     b->size <= offsetof(struct sockaddr_un, sun_path))
 408                         return false;
 409
 410                 if ((a->sockaddr.un.sun_path[0] == 0) != (b->sockaddr.un.sun_path[0] == 0))
 411                         return false;
 412
 413                 if (a->sockaddr.un.sun_path[0]) {
 414                         if (!path_equal_or_files_same(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, 0))
 415                                 return false;
 416                 } else {
 417                         if (a->size != b->size)
 418                                 return false;
 419
 420                         if (memcmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, a->size) != 0)
 421                                 return false;
 422                 }
 423
 424                 break;
 425
 426         case AF_NETLINK:
 427                 if (a->protocol != b->protocol)
 428                         return false;
 429
 430                 if (a->sockaddr.nl.nl_groups != b->sockaddr.nl.nl_groups)
 431                         return false;
 432
 433                 break;
 434
 435         case AF_VSOCK:
 436                 if (a->sockaddr.vm.svm_cid != b->sockaddr.vm.svm_cid)
 437                         return false;
 438
 439                 if (a->sockaddr.vm.svm_port != b->sockaddr.vm.svm_port)
 440                         return false;
 441
 442                 break;
 443
 444         default:
 445                 /* Cannot compare, so we assume the addresses are different */
 446                 return false;
 447         }
 448
 449         return true;
 450 }
 451
 452 bool socket_address_is(const SocketAddress *a, const char *s, int type) {
 453         struct SocketAddress b;
 454
 455         assert(a);
 456         assert(s);
 457
 458         if (socket_address_parse(&b, s) < 0)
 459                 return false;
 460
 461         b.type = type;
 462
 463         return socket_address_equal(a, &b);
 464 }
 465
 466 bool socket_address_is_netlink(const SocketAddress *a, const char *s) {
 467         struct SocketAddress b;
 468
 469         assert(a);
 470         assert(s);
 471
 472         if (socket_address_parse_netlink(&b, s) < 0)
 473                 return false;
 474
 475         return socket_address_equal(a, &b);
 476 }
 477
 478 const char* socket_address_get_path(const SocketAddress *a) {
 479         assert(a);
 480
 481         if (socket_address_family(a) != AF_UNIX)
 482                 return NULL;
 483
 484         if (a->sockaddr.un.sun_path[0] == 0)
 485                 return NULL;
 486
 487         return a->sockaddr.un.sun_path;
 488 }
 489
 490 bool socket_ipv6_is_supported(void) {
 491         if (access("/proc/net/if_inet6", F_OK) != 0)
 492                 return false;
 493
 494         return true;
 495 }
 496
 497 bool socket_address_matches_fd(const SocketAddress *a, int fd) {
 498         SocketAddress b;
 499         socklen_t solen;
 500
 501         assert(a);
 502         assert(fd >= 0);
 503
 504         b.size = sizeof(b.sockaddr);
 505         if (getsockname(fd, &b.sockaddr.sa, &b.size) < 0)
 506                 return false;
 507
 508         if (b.sockaddr.sa.sa_family != a->sockaddr.sa.sa_family)
 509                 return false;
 510
 511         solen = sizeof(b.type);
 512         if (getsockopt(fd, SOL_SOCKET, SO_TYPE, &b.type, &solen) < 0)
 513                 return false;
 514
 515         if (b.type != a->type)
 516                 return false;
 517
 518         if (a->protocol != 0)  {
 519                 solen = sizeof(b.protocol);
 520                 if (getsockopt(fd, SOL_SOCKET, SO_PROTOCOL, &b.protocol, &solen) < 0)
 521                         return false;
 522
 523                 if (b.protocol != a->protocol)
 524                         return false;
 525         }
 526
 527         return socket_address_equal(a, &b);
 528 }
 529
 530 int sockaddr_port(const struct sockaddr *_sa, unsigned *port) {
 531         union sockaddr_union *sa = (union sockaddr_union*) _sa;
 532
 533         assert(sa);
 534
 535         switch (sa->sa.sa_family) {
 536         case AF_INET:
 537                 *port = be16toh(sa->in.sin_port);
 538                 return 0;
 539
 540         case AF_INET6:
 541                 *port = be16toh(sa->in6.sin6_port);
 542                 return 0;
 543
 544         case AF_VSOCK:
 545                 *port = sa->vm.svm_port;
 546                 return 0;
 547
 548         default:
 549                 return -EAFNOSUPPORT;
 550         }
 551 }
 552
 553 int sockaddr_pretty(const struct sockaddr *_sa, socklen_t salen, bool translate_ipv6, bool include_port, char **ret) {
 554         union sockaddr_union *sa = (union sockaddr_union*) _sa;
 555         char *p;
 556         int r;
 557
 558         assert(sa);
 559         assert(salen >= sizeof(sa->sa.sa_family));
 560
 561         switch (sa->sa.sa_family) {
 562
 563         case AF_INET: {
 564                 uint32_t a;
 565
 566                 a = be32toh(sa->in.sin_addr.s_addr);
 567
 568                 if (include_port)
 569                         r = asprintf(&p,
 570                                      "%u.%u.%u.%u:%u",
 571                                      a >> 24, (a >> 16) & 0xFF, (a >> 8) & 0xFF, a & 0xFF,
 572                                      be16toh(sa->in.sin_port));
 573                 else
 574                         r = asprintf(&p,
 575                                      "%u.%u.%u.%u",
 576                                      a >> 24, (a >> 16) & 0xFF, (a >> 8) & 0xFF, a & 0xFF);
 577                 if (r < 0)
 578                         return -ENOMEM;
 579                 break;
 580         }
 581
 582         case AF_INET6: {
 583                 static const unsigned char ipv4_prefix[] = {
 584                         0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF
 585                 };
 586
 587                 if (translate_ipv6 &&
 588                     memcmp(&sa->in6.sin6_addr, ipv4_prefix, sizeof(ipv4_prefix)) == 0) {
 589                         const uint8_t *a = sa->in6.sin6_addr.s6_addr+12;
 590                         if (include_port)
 591                                 r = asprintf(&p,
 592                                              "%u.%u.%u.%u:%u",
 593                                              a[0], a[1], a[2], a[3],
 594                                              be16toh(sa->in6.sin6_port));
 595                         else
 596                                 r = asprintf(&p,
 597                                              "%u.%u.%u.%u",
 598                                              a[0], a[1], a[2], a[3]);
 599                         if (r < 0)
 600                                 return -ENOMEM;
 601                 } else {
 602                         char a[INET6_ADDRSTRLEN];
 603
 604                         inet_ntop(AF_INET6, &sa->in6.sin6_addr, a, sizeof(a));
 605
 606                         if (include_port) {
 607                                 r = asprintf(&p,
 608                                              "[%s]:%u",
 609                                              a,
 610                                              be16toh(sa->in6.sin6_port));
 611                                 if (r < 0)
 612                                         return -ENOMEM;
 613                         } else {
 614                                 p = strdup(a);
 615                                 if (!p)
 616                                         return -ENOMEM;
 617                         }
 618                 }
 619
 620                 break;
 621         }
 622
 623         case AF_UNIX:
 624                 if (salen <= offsetof(struct sockaddr_un, sun_path)) {
 625                         p = strdup("<unnamed>");
 626                         if (!p)
 627                                 return -ENOMEM;
 628
 629                 } else if (sa->un.sun_path[0] == 0) {
 630                         /* abstract */
 631
 632                         /* FIXME: We assume we can print the
 633                          * socket path here and that it hasn't
 634                          * more than one NUL byte. That is
 635                          * actually an invalid assumption */
 636
 637                         p = new(char, sizeof(sa->un.sun_path)+1);
 638                         if (!p)
 639                                 return -ENOMEM;
 640
 641                         p[0] = '@';
 642                         memcpy(p+1, sa->un.sun_path+1, sizeof(sa->un.sun_path)-1);
 643                         p[sizeof(sa->un.sun_path)] = 0;
 644
 645                 } else {
 646                         p = strndup(sa->un.sun_path, sizeof(sa->un.sun_path));
 647                         if (!p)
 648                                 return -ENOMEM;
 649                 }
 650
 651                 break;
 652
 653         case AF_VSOCK:
 654                 if (include_port)
 655                         r = asprintf(&p,
 656                                      "vsock:%u:%u",
 657                                      sa->vm.svm_cid,
 658                                      sa->vm.svm_port);
 659                 else
 660                         r = asprintf(&p, "vsock:%u", sa->vm.svm_cid);
 661                 if (r < 0)
 662                         return -ENOMEM;
 663                 break;
 664
 665         default:
 666                 return -EOPNOTSUPP;
 667         }
 668
 669
 670         *ret = p;
 671         return 0;
 672 }
 673
 674 int getpeername_pretty(int fd, bool include_port, char **ret) {
 675         union sockaddr_union sa;
 676         socklen_t salen = sizeof(sa);
 677         int r;
 678
 679         assert(fd >= 0);
 680         assert(ret);
 681
 682         if (getpeername(fd, &sa.sa, &salen) < 0)
 683                 return -errno;
 684
 685         if (sa.sa.sa_family == AF_UNIX) {
 686                 struct ucred ucred = {};
 687
 688                 /* UNIX connection sockets are anonymous, so let's use
 689                  * PID/UID as pretty credentials instead */
 690
 691                 r = getpeercred(fd, &ucred);
 692                 if (r < 0)
 693                         return r;
 694
 695                 if (asprintf(ret, "PID "PID_FMT"/UID "UID_FMT, ucred.pid, ucred.uid) < 0)
 696                         return -ENOMEM;
 697
 698                 return 0;
 699         }
 700
 701         /* For remote sockets we translate IPv6 addresses back to IPv4
 702          * if applicable, since that's nicer. */
 703
 704         return sockaddr_pretty(&sa.sa, salen, true, include_port, ret);
 705 }
 706
 707 int getsockname_pretty(int fd, char **ret) {
 708         union sockaddr_union sa;
 709         socklen_t salen = sizeof(sa);
 710
 711         assert(fd >= 0);
 712         assert(ret);
 713
 714         if (getsockname(fd, &sa.sa, &salen) < 0)
 715                 return -errno;
 716
 717         /* For local sockets we do not translate IPv6 addresses back
 718          * to IPv6 if applicable, since this is usually used for
 719          * listening sockets where the difference between IPv4 and
 720          * IPv6 matters. */
 721
 722         return sockaddr_pretty(&sa.sa, salen, false, true, ret);
 723 }
 724
 725 int socknameinfo_pretty(union sockaddr_union *sa, socklen_t salen, char **_ret) {
 726         int r;
 727         char host[NI_MAXHOST], *ret;
 728
 729         assert(_ret);
 730
 731         r = getnameinfo(&sa->sa, salen, host, sizeof(host), NULL, 0, IDN_FLAGS);
 732         if (r != 0) {
 733                 int saved_errno = errno;
 734
 735                 r = sockaddr_pretty(&sa->sa, salen, true, true, &ret);
 736                 if (r < 0)
 737                         return r;
 738
 739                 log_debug_errno(saved_errno, "getnameinfo(%s) failed: %m", ret);
 740         } else {
 741                 ret = strdup(host);
 742                 if (!ret)
 743                         return -ENOMEM;
 744         }
 745
 746         *_ret = ret;
 747         return 0;
 748 }
 749
 750 int getnameinfo_pretty(int fd, char **ret) {
 751         union sockaddr_union sa;
 752         socklen_t salen = sizeof(sa);
 753
 754         assert(fd >= 0);
 755         assert(ret);
 756
 757         if (getsockname(fd, &sa.sa, &salen) < 0)
 758                 return -errno;
 759
 760         return socknameinfo_pretty(&sa, salen, ret);
 761 }
 762
 763 int socket_address_unlink(SocketAddress *a) {
 764         assert(a);
 765
 766         if (socket_address_family(a) != AF_UNIX)
 767                 return 0;
 768
 769         if (a->sockaddr.un.sun_path[0] == 0)
 770                 return 0;
 771
 772         if (unlink(a->sockaddr.un.sun_path) < 0)
 773                 return -errno;
 774
 775         return 1;
 776 }
 777
 778 static const char* const netlink_family_table[] = {
 779         [NETLINK_ROUTE] = "route",
 780         [NETLINK_FIREWALL] = "firewall",
 781         [NETLINK_INET_DIAG] = "inet-diag",
 782         [NETLINK_NFLOG] = "nflog",
 783         [NETLINK_XFRM] = "xfrm",
 784         [NETLINK_SELINUX] = "selinux",
 785         [NETLINK_ISCSI] = "iscsi",
 786         [NETLINK_AUDIT] = "audit",
 787         [NETLINK_FIB_LOOKUP] = "fib-lookup",
 788         [NETLINK_CONNECTOR] = "connector",
 789         [NETLINK_NETFILTER] = "netfilter",
 790         [NETLINK_IP6_FW] = "ip6-fw",
 791         [NETLINK_DNRTMSG] = "dnrtmsg",
 792         [NETLINK_KOBJECT_UEVENT] = "kobject-uevent",
 793         [NETLINK_GENERIC] = "generic",
 794         [NETLINK_SCSITRANSPORT] = "scsitransport",
 795         [NETLINK_ECRYPTFS] = "ecryptfs",
 796         [NETLINK_RDMA] = "rdma",
 797 };
 798
 799 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(netlink_family, int, INT_MAX);
 800
 801 static const char* const socket_address_bind_ipv6_only_table[_SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX] = {
 802         [SOCKET_ADDRESS_DEFAULT] = "default",
 803         [SOCKET_ADDRESS_BOTH] = "both",
 804         [SOCKET_ADDRESS_IPV6_ONLY] = "ipv6-only"
 805 };
 806
 807 DEFINE_STRING_TABLE_LOOKUP(socket_address_bind_ipv6_only, SocketAddressBindIPv6Only);
 808
 809 bool sockaddr_equal(const union sockaddr_union *a, const union sockaddr_union *b) {
 810         assert(a);
 811         assert(b);
 812
 813         if (a->sa.sa_family != b->sa.sa_family)
 814                 return false;
 815
 816         if (a->sa.sa_family == AF_INET)
 817                 return a->in.sin_addr.s_addr == b->in.sin_addr.s_addr;
 818
 819         if (a->sa.sa_family == AF_INET6)
 820                 return memcmp(&a->in6.sin6_addr, &b->in6.sin6_addr, sizeof(a->in6.sin6_addr)) == 0;
 821
 822         if (a->sa.sa_family == AF_VSOCK)
 823                 return a->vm.svm_cid == b->vm.svm_cid;
 824
 825         return false;
 826 }
 827
 828 int fd_inc_sndbuf(int fd, size_t n) {
 829         int r, value;
 830         socklen_t l = sizeof(value);
 831
 832         r = getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, &l);
 833         if (r >= 0 && l == sizeof(value) && (size_t) value >= n*2)
 834                 return 0;
 835
 836         /* If we have the privileges we will ignore the kernel limit. */
 837
 838         value = (int) n;
 839         if (setsockopt(fd, SOL_SOCKET, SO_SNDBUFFORCE, &value, sizeof(value)) < 0)
 840                 if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &value, sizeof(value)) < 0)
 841                         return -errno;
 842
 843         return 1;
 844 }
 845
 846 int fd_inc_rcvbuf(int fd, size_t n) {
 847         int r, value;
 848         socklen_t l = sizeof(value);
 849
 850         r = getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, &l);
 851         if (r >= 0 && l == sizeof(value) && (size_t) value >= n*2)
 852                 return 0;
 853
 854         /* If we have the privileges we will ignore the kernel limit. */
 855
 856         value = (int) n;
 857         if (setsockopt(fd, SOL_SOCKET, SO_RCVBUFFORCE, &value, sizeof(value)) < 0)
 858                 if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &value, sizeof(value)) < 0)
 859                         return -errno;
 860         return 1;
 861 }
 862
 863 static const char* const ip_tos_table[] = {
 864         [IPTOS_LOWDELAY] = "low-delay",
 865         [IPTOS_THROUGHPUT] = "throughput",
 866         [IPTOS_RELIABILITY] = "reliability",
 867         [IPTOS_LOWCOST] = "low-cost",
 868 };
 869
 870 DEFINE_STRING_TABLE_LOOKUP_WITH_FALLBACK(ip_tos, int, 0xff);
 871
 872 bool ifname_valid(const char *p) {
 873         bool numeric = true;
 874
 875         /* Checks whether a network interface name is valid. This is inspired by dev_valid_name() in the kernel sources
 876          * but slightly stricter, as we only allow non-control, non-space ASCII characters in the interface name. We
 877          * also don't permit names that only container numbers, to avoid confusion with numeric interface indexes. */
 878
 879         if (isempty(p))
 880                 return false;
 881
 882         if (strlen(p) >= IFNAMSIZ)
 883                 return false;
 884
 885         if (dot_or_dot_dot(p))
 886                 return false;
 887
 888         while (*p) {
 889                 if ((unsigned char) *p >= 127U)
 890                         return false;
 891
 892                 if ((unsigned char) *p <= 32U)
 893                         return false;
 894
 895                 if (*p == ':' || *p == '/')
 896                         return false;
 897
 898                 numeric = numeric && (*p >= '0' && *p <= '9');
 899                 p++;
 900         }
 901
 902         if (numeric)
 903                 return false;
 904
 905         return true;
 906 }
 907
 908 bool address_label_valid(const char *p) {
 909
 910         if (isempty(p))
 911                 return false;
 912
 913         if (strlen(p) >= IFNAMSIZ)
 914                 return false;
 915
 916         while (*p) {
 917                 if ((uint8_t) *p >= 127U)
 918                         return false;
 919
 920                 if ((uint8_t) *p <= 31U)
 921                         return false;
 922                 p++;
 923         }
 924
 925         return true;
 926 }
 927
 928 int getpeercred(int fd, struct ucred *ucred) {
 929         socklen_t n = sizeof(struct ucred);
 930         struct ucred u;
 931         int r;
 932
 933         assert(fd >= 0);
 934         assert(ucred);
 935
 936         r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &u, &n);
 937         if (r < 0)
 938                 return -errno;
 939
 940         if (n != sizeof(struct ucred))
 941                 return -EIO;
 942
 943         /* Check if the data is actually useful and not suppressed due
 944          * to namespacing issues */
 945         if (u.pid <= 0)
 946                 return -ENODATA;
 947         if (u.uid == UID_INVALID)
 948                 return -ENODATA;
 949         if (u.gid == GID_INVALID)
 950                 return -ENODATA;
 951
 952         *ucred = u;
 953         return 0;
 954 }
 955
 956 int getpeersec(int fd, char **ret) {
 957         socklen_t n = 64;
 958         char *s;
 959         int r;
 960
 961         assert(fd >= 0);
 962         assert(ret);
 963
 964         s = new0(char, n);
 965         if (!s)
 966                 return -ENOMEM;
 967
 968         r = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n);
 969         if (r < 0) {
 970                 free(s);
 971
 972                 if (errno != ERANGE)
 973                         return -errno;
 974
 975                 s = new0(char, n);
 976                 if (!s)
 977                         return -ENOMEM;
 978
 979                 r = getsockopt(fd, SOL_SOCKET, SO_PEERSEC, s, &n);
 980                 if (r < 0) {
 981                         free(s);
 982                         return -errno;
 983                 }
 984         }
 985
 986         if (isempty(s)) {
 987                 free(s);
 988                 return -EOPNOTSUPP;
 989         }
 990
 991         *ret = s;
 992         return 0;
 993 }
 994
 995 int send_one_fd_sa(
 996                 int transport_fd,
 997                 int fd,
 998                 const struct sockaddr *sa, socklen_t len,
 999                 int flags) {
1000
1001         union {
1002                 struct cmsghdr cmsghdr;
1003                 uint8_t buf[CMSG_SPACE(sizeof(int))];
1004         } control = {};
1005         struct msghdr mh = {
1006                 .msg_name = (struct sockaddr*) sa,
1007                 .msg_namelen = len,
1008                 .msg_control = &control,
1009                 .msg_controllen = sizeof(control),
1010         };
1011         struct cmsghdr *cmsg;
1012
1013         assert(transport_fd >= 0);
1014         assert(fd >= 0);
1015
1016         cmsg = CMSG_FIRSTHDR(&mh);
1017         cmsg->cmsg_level = SOL_SOCKET;
1018         cmsg->cmsg_type = SCM_RIGHTS;
1019         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
1020         memcpy(CMSG_DATA(cmsg), &fd, sizeof(int));
1021
1022         mh.msg_controllen = CMSG_SPACE(sizeof(int));
1023         if (sendmsg(transport_fd, &mh, MSG_NOSIGNAL | flags) < 0)
1024                 return -errno;
1025
1026         return 0;
1027 }
1028
1029 int receive_one_fd(int transport_fd, int flags) {
1030         union {
1031                 struct cmsghdr cmsghdr;
1032                 uint8_t buf[CMSG_SPACE(sizeof(int))];
1033         } control = {};
1034         struct msghdr mh = {
1035                 .msg_control = &control,
1036                 .msg_controllen = sizeof(control),
1037         };
1038         struct cmsghdr *cmsg, *found = NULL;
1039
1040         assert(transport_fd >= 0);
1041
1042         /*
1043          * Receive a single FD via @transport_fd. We don't care for
1044          * the transport-type. We retrieve a single FD at most, so for
1045          * packet-based transports, the caller must ensure to send
1046          * only a single FD per packet.  This is best used in
1047          * combination with send_one_fd().
1048          */
1049
1050         if (recvmsg(transport_fd, &mh, MSG_NOSIGNAL | MSG_CMSG_CLOEXEC | flags) < 0)
1051                 return -errno;
1052
1053         CMSG_FOREACH(cmsg, &mh) {
1054                 if (cmsg->cmsg_level == SOL_SOCKET &&
1055                     cmsg->cmsg_type == SCM_RIGHTS &&
1056                     cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
1057                         assert(!found);
1058                         found = cmsg;
1059                         break;
1060                 }
1061         }
1062
1063         if (!found) {
1064                 cmsg_close_all(&mh);
1065                 return -EIO;
1066         }
1067
1068         return *(int*) CMSG_DATA(found);
1069 }
1070
1071 ssize_t next_datagram_size_fd(int fd) {
1072         ssize_t l;
1073         int k;
1074
1075         /* This is a bit like FIONREAD/SIOCINQ, however a bit more powerful. The difference being: recv(MSG_PEEK) will
1076          * actually cause the next datagram in the queue to be validated regarding checksums, which FIONREAD doesn't
1077          * do. This difference is actually of major importance as we need to be sure that the size returned here
1078          * actually matches what we will read with recvmsg() next, as otherwise we might end up allocating a buffer of
1079          * the wrong size. */
1080
1081         l = recv(fd, NULL, 0, MSG_PEEK|MSG_TRUNC);
1082         if (l < 0) {
1083                 if (IN_SET(errno, EOPNOTSUPP, EFAULT))
1084                         goto fallback;
1085
1086                 return -errno;
1087         }
1088         if (l == 0)
1089                 goto fallback;
1090
1091         return l;
1092
1093 fallback:
1094         k = 0;
1095
1096         /* Some sockets (AF_PACKET) do not support null-sized recv() with MSG_TRUNC set, let's fall back to FIONREAD
1097          * for them. Checksums don't matter for raw sockets anyway, hence this should be fine. */
1098
1099         if (ioctl(fd, FIONREAD, &k) < 0)
1100                 return -errno;
1101
1102         return (ssize_t) k;
1103 }
1104
1105 int flush_accept(int fd) {
1106
1107         struct pollfd pollfd = {
1108                 .fd = fd,
1109                 .events = POLLIN,
1110         };
1111         int r;
1112
1113
1114         /* Similar to flush_fd() but flushes all incoming connection by accepting them and immediately closing them. */
1115
1116         for (;;) {
1117                 int cfd;
1118
1119                 r = poll(&pollfd, 1, 0);
1120                 if (r < 0) {
1121                         if (errno == EINTR)
1122                                 continue;
1123
1124                         return -errno;
1125
1126                 } else if (r == 0)
1127                         return 0;
1128
1129                 cfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
1130                 if (cfd < 0) {
1131                         if (errno == EINTR)
1132                                 continue;
1133
1134                         if (errno == EAGAIN)
1135                                 return 0;
1136
1137                         return -errno;
1138                 }
1139
1140                 close(cfd);
1141         }
1142 }
1143
1144 struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t length) {
1145         struct cmsghdr *cmsg;
1146
1147         assert(mh);
1148
1149         CMSG_FOREACH(cmsg, mh)
1150                 if (cmsg->cmsg_level == level &&
1151                     cmsg->cmsg_type == type &&
1152                     (length == (socklen_t) -1 || length == cmsg->cmsg_len))
1153                         return cmsg;
1154
1155         return NULL;
1156 }
1157
1158 int socket_ioctl_fd(void) {
1159         int fd;
1160
1161         /* Create a socket to invoke the various network interface ioctl()s on. Traditionally only AF_INET was good for
1162          * that. Since kernel 4.6 AF_NETLINK works for this too. We first try to use AF_INET hence, but if that's not
1163          * available (for example, because it is made unavailable via SECCOMP or such), we'll fall back to the more
1164          * generic AF_NETLINK. */
1165
1166         fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
1167         if (fd < 0)
1168                 fd = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_GENERIC);
1169         if (fd < 0)
1170                 return -errno;
1171
1172         return fd;
1173 }