src/socket-util.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <assert.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <errno.h>
  26 #include <stdlib.h>
  27 #include <arpa/inet.h>
  28 #include <stdio.h>
  29 #include <net/if.h>
  30 #include <sys/types.h>
  31 #include <sys/stat.h>
  32 #include <stddef.h>
  33 #include <sys/ioctl.h>
  34
  35 #include "macro.h"
  36 #include "util.h"
  37 #include "socket-util.h"
  38 #include "missing.h"
  39 #include "label.h"
  40
  41 int socket_address_parse(SocketAddress *a, const char *s) {
  42         int r;
  43         char *e, *n;
  44         unsigned u;
  45
  46         assert(a);
  47         assert(s);
  48
  49         zero(*a);
  50         a->type = SOCK_STREAM;
  51
  52         if (*s == '[') {
  53                 /* IPv6 in [x:.....:z]:p notation */
  54
  55                 if (!socket_ipv6_is_supported()) {
  56                         log_warning("Binding to IPv6 address not available since kernel does not support IPv6.");
  57                         return -EAFNOSUPPORT;
  58                 }
  59
  60                 if (!(e = strchr(s+1, ']')))
  61                         return -EINVAL;
  62
  63                 if (!(n = strndup(s+1, e-s-1)))
  64                         return -ENOMEM;
  65
  66                 errno = 0;
  67                 if (inet_pton(AF_INET6, n, &a->sockaddr.in6.sin6_addr) <= 0) {
  68                         free(n);
  69                         return errno != 0 ? -errno : -EINVAL;
  70                 }
  71
  72                 free(n);
  73
  74                 e++;
  75                 if (*e != ':')
  76                         return -EINVAL;
  77
  78                 e++;
  79                 if ((r = safe_atou(e, &u)) < 0)
  80                         return r;
  81
  82                 if (u <= 0 || u > 0xFFFF)
  83                         return -EINVAL;
  84
  85                 a->sockaddr.in6.sin6_family = AF_INET6;
  86                 a->sockaddr.in6.sin6_port = htons((uint16_t) u);
  87                 a->size = sizeof(struct sockaddr_in6);
  88
  89         } else if (*s == '/') {
  90                 /* AF_UNIX socket */
  91
  92                 size_t l;
  93
  94                 l = strlen(s);
  95                 if (l >= sizeof(a->sockaddr.un.sun_path))
  96                         return -EINVAL;
  97
  98                 a->sockaddr.un.sun_family = AF_UNIX;
  99                 memcpy(a->sockaddr.un.sun_path, s, l);
 100                 a->size = offsetof(struct sockaddr_un, sun_path) + l + 1;
 101
 102         } else if (*s == '@') {
 103                 /* Abstract AF_UNIX socket */
 104                 size_t l;
 105
 106                 l = strlen(s+1);
 107                 if (l >= sizeof(a->sockaddr.un.sun_path) - 1)
 108                         return -EINVAL;
 109
 110                 a->sockaddr.un.sun_family = AF_UNIX;
 111                 memcpy(a->sockaddr.un.sun_path+1, s+1, l);
 112                 a->size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
 113
 114         } else {
 115
 116                 if ((e = strchr(s, ':'))) {
 117
 118                         if ((r = safe_atou(e+1, &u)) < 0)
 119                                 return r;
 120
 121                         if (u <= 0 || u > 0xFFFF)
 122                                 return -EINVAL;
 123
 124                         if (!(n = strndup(s, e-s)))
 125                                 return -ENOMEM;
 126
 127                         /* IPv4 in w.x.y.z:p notation? */
 128                         if ((r = inet_pton(AF_INET, n, &a->sockaddr.in4.sin_addr)) < 0) {
 129                                 free(n);
 130                                 return -errno;
 131                         }
 132
 133                         if (r > 0) {
 134                                 /* Gotcha, it's a traditional IPv4 address */
 135                                 free(n);
 136
 137                                 a->sockaddr.in4.sin_family = AF_INET;
 138                                 a->sockaddr.in4.sin_port = htons((uint16_t) u);
 139                                 a->size = sizeof(struct sockaddr_in);
 140                         } else {
 141                                 unsigned idx;
 142
 143                                 if (strlen(n) > IF_NAMESIZE-1) {
 144                                         free(n);
 145                                         return -EINVAL;
 146                                 }
 147
 148                                 /* Uh, our last resort, an interface name */
 149                                 idx = if_nametoindex(n);
 150                                 free(n);
 151
 152                                 if (idx == 0)
 153                                         return -EINVAL;
 154
 155                                 if (!socket_ipv6_is_supported()) {
 156                                         log_warning("Binding to interface is not available since kernel does not support IPv6.");
 157                                         return -EAFNOSUPPORT;
 158                                 }
 159
 160                                 a->sockaddr.in6.sin6_family = AF_INET6;
 161                                 a->sockaddr.in6.sin6_port = htons((uint16_t) u);
 162                                 a->sockaddr.in6.sin6_scope_id = idx;
 163                                 a->sockaddr.in6.sin6_addr = in6addr_any;
 164                                 a->size = sizeof(struct sockaddr_in6);
 165                         }
 166                 } else {
 167
 168                         /* Just a port */
 169                         if ((r = safe_atou(s, &u)) < 0)
 170                                 return r;
 171
 172                         if (u <= 0 || u > 0xFFFF)
 173                                 return -EINVAL;
 174
 175                         if (socket_ipv6_is_supported()) {
 176                                 a->sockaddr.in6.sin6_family = AF_INET6;
 177                                 a->sockaddr.in6.sin6_port = htons((uint16_t) u);
 178                                 a->sockaddr.in6.sin6_addr = in6addr_any;
 179                                 a->size = sizeof(struct sockaddr_in6);
 180                         } else {
 181                                 a->sockaddr.in4.sin_family = AF_INET;
 182                                 a->sockaddr.in4.sin_port = htons((uint16_t) u);
 183                                 a->sockaddr.in4.sin_addr.s_addr = INADDR_ANY;
 184                                 a->size = sizeof(struct sockaddr_in);
 185                         }
 186                 }
 187         }
 188
 189         return 0;
 190 }
 191
 192 int socket_address_parse_netlink(SocketAddress *a, const char *s) {
 193         int family;
 194         unsigned group = 0;
 195         char* sfamily = NULL;
 196         assert(a);
 197         assert(s);
 198
 199         zero(*a);
 200         a->type = SOCK_RAW;
 201
 202         errno = 0;
 203         if (sscanf(s, "%ms %u", &sfamily, &group) < 1)
 204                 return errno ? -errno : -EINVAL;
 205
 206         if ((family = netlink_family_from_string(sfamily)) < 0)
 207                 if (safe_atoi(sfamily, &family) < 0) {
 208                         free(sfamily);
 209                         return -EINVAL;
 210                 }
 211
 212         free(sfamily);
 213
 214         a->sockaddr.nl.nl_family = AF_NETLINK;
 215         a->sockaddr.nl.nl_groups = group;
 216
 217         a->type = SOCK_RAW;
 218         a->size = sizeof(struct sockaddr_nl);
 219         a->protocol = family;
 220
 221         return 0;
 222 }
 223
 224 int socket_address_verify(const SocketAddress *a) {
 225         assert(a);
 226
 227         switch (socket_address_family(a)) {
 228
 229         case AF_INET:
 230                 if (a->size != sizeof(struct sockaddr_in))
 231                         return -EINVAL;
 232
 233                 if (a->sockaddr.in4.sin_port == 0)
 234                         return -EINVAL;
 235
 236                 if (a->type != SOCK_STREAM && a->type != SOCK_DGRAM)
 237                         return -EINVAL;
 238
 239                 return 0;
 240
 241         case AF_INET6:
 242                 if (a->size != sizeof(struct sockaddr_in6))
 243                         return -EINVAL;
 244
 245                 if (a->sockaddr.in6.sin6_port == 0)
 246                         return -EINVAL;
 247
 248                 if (a->type != SOCK_STREAM && a->type != SOCK_DGRAM)
 249                         return -EINVAL;
 250
 251                 return 0;
 252
 253         case AF_UNIX:
 254                 if (a->size < offsetof(struct sockaddr_un, sun_path))
 255                         return -EINVAL;
 256
 257                 if (a->size > offsetof(struct sockaddr_un, sun_path)) {
 258
 259                         if (a->sockaddr.un.sun_path[0] != 0) {
 260                                 char *e;
 261
 262                                 /* path */
 263                                 if (!(e = memchr(a->sockaddr.un.sun_path, 0, sizeof(a->sockaddr.un.sun_path))))
 264                                         return -EINVAL;
 265
 266                                 if (a->size != offsetof(struct sockaddr_un, sun_path) + (e - a->sockaddr.un.sun_path) + 1)
 267                                         return -EINVAL;
 268                         }
 269                 }
 270
 271                 if (a->type != SOCK_STREAM && a->type != SOCK_DGRAM && a->type != SOCK_SEQPACKET)
 272                         return -EINVAL;
 273
 274                 return 0;
 275
 276         case AF_NETLINK:
 277
 278                 if (a->size != sizeof(struct sockaddr_nl))
 279                         return -EINVAL;
 280
 281                 if (a->type != SOCK_RAW && a->type != SOCK_DGRAM)
 282                         return -EINVAL;
 283
 284                 return 0;
 285
 286         default:
 287                 return -EAFNOSUPPORT;
 288         }
 289 }
 290
 291 int socket_address_print(const SocketAddress *a, char **p) {
 292         int r;
 293         assert(a);
 294         assert(p);
 295
 296         if ((r = socket_address_verify(a)) < 0)
 297                 return r;
 298
 299         switch (socket_address_family(a)) {
 300
 301         case AF_INET: {
 302                 char *ret;
 303
 304                 if (!(ret = new(char, INET_ADDRSTRLEN+1+5+1)))
 305                         return -ENOMEM;
 306
 307                 if (!inet_ntop(AF_INET, &a->sockaddr.in4.sin_addr, ret, INET_ADDRSTRLEN)) {
 308                         free(ret);
 309                         return -errno;
 310                 }
 311
 312                 sprintf(strchr(ret, 0), ":%u", ntohs(a->sockaddr.in4.sin_port));
 313                 *p = ret;
 314                 return 0;
 315         }
 316
 317         case AF_INET6: {
 318                 char *ret;
 319
 320                 if (!(ret = new(char, 1+INET6_ADDRSTRLEN+2+5+1)))
 321                         return -ENOMEM;
 322
 323                 ret[0] = '[';
 324                 if (!inet_ntop(AF_INET6, &a->sockaddr.in6.sin6_addr, ret+1, INET6_ADDRSTRLEN)) {
 325                         free(ret);
 326                         return -errno;
 327                 }
 328
 329                 sprintf(strchr(ret, 0), "]:%u", ntohs(a->sockaddr.in6.sin6_port));
 330                 *p = ret;
 331                 return 0;
 332         }
 333
 334         case AF_UNIX: {
 335                 char *ret;
 336
 337                 if (a->size <= offsetof(struct sockaddr_un, sun_path)) {
 338
 339                         if (!(ret = strdup("<unnamed>")))
 340                                 return -ENOMEM;
 341
 342                 } else if (a->sockaddr.un.sun_path[0] == 0) {
 343                         /* abstract */
 344
 345                         /* FIXME: We assume we can print the
 346                          * socket path here and that it hasn't
 347                          * more than one NUL byte. That is
 348                          * actually an invalid assumption */
 349
 350                         if (!(ret = new(char, sizeof(a->sockaddr.un.sun_path)+1)))
 351                                 return -ENOMEM;
 352
 353                         ret[0] = '@';
 354                         memcpy(ret+1, a->sockaddr.un.sun_path+1, sizeof(a->sockaddr.un.sun_path)-1);
 355                         ret[sizeof(a->sockaddr.un.sun_path)] = 0;
 356
 357                 } else {
 358
 359                         if (!(ret = strdup(a->sockaddr.un.sun_path)))
 360                                 return -ENOMEM;
 361                 }
 362
 363                 *p = ret;
 364                 return 0;
 365         }
 366
 367         case AF_NETLINK: {
 368                 const char *sfamily;
 369
 370                 if ((sfamily = netlink_family_to_string(a->protocol)))
 371                         r = asprintf(p, "%s %u", sfamily, a->sockaddr.nl.nl_groups);
 372                 else
 373                         r = asprintf(p, "%i %u", a->protocol, a->sockaddr.nl.nl_groups);
 374
 375                 if (r < 0)
 376                         return -ENOMEM;
 377
 378                 return 0;
 379         }
 380
 381         default:
 382                 return -EINVAL;
 383         }
 384 }
 385
 386 int socket_address_listen(
 387                 const SocketAddress *a,
 388                 int backlog,
 389                 SocketAddressBindIPv6Only only,
 390                 const char *bind_to_device,
 391                 bool free_bind,
 392                 bool transparent,
 393                 mode_t directory_mode,
 394                 mode_t socket_mode,
 395                 const char *label,
 396                 int *ret) {
 397
 398         int r, fd, one;
 399         assert(a);
 400         assert(ret);
 401
 402         if ((r = socket_address_verify(a)) < 0)
 403                 return r;
 404
 405         if (socket_address_family(a) == AF_INET6 && !socket_ipv6_is_supported())
 406                 return -EAFNOSUPPORT;
 407
 408         r = label_socket_set(label);
 409         if (r < 0)
 410                 return r;
 411
 412         fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, a->protocol);
 413         r = fd < 0 ? -errno : 0;
 414
 415         label_socket_clear();
 416
 417         if (r < 0)
 418                 return r;
 419
 420         if (socket_address_family(a) == AF_INET6 && only != SOCKET_ADDRESS_DEFAULT) {
 421                 int flag = only == SOCKET_ADDRESS_IPV6_ONLY;
 422
 423                 if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &flag, sizeof(flag)) < 0)
 424                         goto fail;
 425         }
 426
 427         if (socket_address_family(a) == AF_INET || socket_address_family(a) == AF_INET6) {
 428                 if (bind_to_device)
 429                         if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, bind_to_device, strlen(bind_to_device)+1) < 0)
 430                                 goto fail;
 431
 432                 if (free_bind) {
 433                         one = 1;
 434                         if (setsockopt(fd, IPPROTO_IP, IP_FREEBIND, &one, sizeof(one)) < 0)
 435                                 log_warning("IP_FREEBIND failed: %m");
 436                 }
 437
 438                 if (transparent) {
 439                         one = 1;
 440                         if (setsockopt(fd, IPPROTO_IP, IP_TRANSPARENT, &one, sizeof(one)) < 0)
 441                                 log_warning("IP_TRANSPARENT failed: %m");
 442                 }
 443         }
 444
 445         one = 1;
 446         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0)
 447                 goto fail;
 448
 449         if (socket_address_family(a) == AF_UNIX && a->sockaddr.un.sun_path[0] != 0) {
 450                 mode_t old_mask;
 451
 452                 /* Create parents */
 453                 mkdir_parents(a->sockaddr.un.sun_path, directory_mode);
 454
 455                 /* Enforce the right access mode for the socket*/
 456                 old_mask = umask(~ socket_mode);
 457
 458                 /* Include the original umask in our mask */
 459                 umask(~socket_mode | old_mask);
 460
 461                 r = bind(fd, &a->sockaddr.sa, a->size);
 462
 463                 if (r < 0 && errno == EADDRINUSE) {
 464                         /* Unlink and try again */
 465                         unlink(a->sockaddr.un.sun_path);
 466                         r = bind(fd, &a->sockaddr.sa, a->size);
 467                 }
 468
 469                 umask(old_mask);
 470         } else
 471                 r = bind(fd, &a->sockaddr.sa, a->size);
 472
 473         if (r < 0)
 474                 goto fail;
 475
 476         if (socket_address_can_accept(a))
 477                 if (listen(fd, backlog) < 0)
 478                         goto fail;
 479
 480         *ret = fd;
 481         return 0;
 482
 483 fail:
 484         r = -errno;
 485         close_nointr_nofail(fd);
 486         return r;
 487 }
 488
 489 bool socket_address_can_accept(const SocketAddress *a) {
 490         assert(a);
 491
 492         return
 493                 a->type == SOCK_STREAM ||
 494                 a->type == SOCK_SEQPACKET;
 495 }
 496
 497 bool socket_address_equal(const SocketAddress *a, const SocketAddress *b) {
 498         assert(a);
 499         assert(b);
 500
 501         /* Invalid addresses are unequal to all */
 502         if (socket_address_verify(a) < 0 ||
 503             socket_address_verify(b) < 0)
 504                 return false;
 505
 506         if (a->type != b->type)
 507                 return false;
 508
 509         if (a->size != b->size)
 510                 return false;
 511
 512         if (socket_address_family(a) != socket_address_family(b))
 513                 return false;
 514
 515         switch (socket_address_family(a)) {
 516
 517         case AF_INET:
 518                 if (a->sockaddr.in4.sin_addr.s_addr != b->sockaddr.in4.sin_addr.s_addr)
 519                         return false;
 520
 521                 if (a->sockaddr.in4.sin_port != b->sockaddr.in4.sin_port)
 522                         return false;
 523
 524                 break;
 525
 526         case AF_INET6:
 527                 if (memcmp(&a->sockaddr.in6.sin6_addr, &b->sockaddr.in6.sin6_addr, sizeof(a->sockaddr.in6.sin6_addr)) != 0)
 528                         return false;
 529
 530                 if (a->sockaddr.in6.sin6_port != b->sockaddr.in6.sin6_port)
 531                         return false;
 532
 533                 break;
 534
 535         case AF_UNIX:
 536
 537                 if ((a->sockaddr.un.sun_path[0] == 0) != (b->sockaddr.un.sun_path[0] == 0))
 538                         return false;
 539
 540                 if (a->sockaddr.un.sun_path[0]) {
 541                         if (strncmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, sizeof(a->sockaddr.un.sun_path)) != 0)
 542                                 return false;
 543                 } else {
 544                         if (memcmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, a->size) != 0)
 545                                 return false;
 546                 }
 547
 548                 break;
 549
 550         case AF_NETLINK:
 551
 552                 if (a->protocol != b->protocol)
 553                         return false;
 554
 555                 if (a->sockaddr.nl.nl_groups != b->sockaddr.nl.nl_groups)
 556                         return false;
 557
 558                 break;
 559
 560         default:
 561                 /* Cannot compare, so we assume the addresses are different */
 562                 return false;
 563         }
 564
 565         return true;
 566 }
 567
 568 bool socket_address_is(const SocketAddress *a, const char *s, int type) {
 569         struct SocketAddress b;
 570
 571         assert(a);
 572         assert(s);
 573
 574         if (socket_address_parse(&b, s) < 0)
 575                 return false;
 576
 577         b.type = type;
 578
 579         return socket_address_equal(a, &b);
 580 }
 581
 582 bool socket_address_is_netlink(const SocketAddress *a, const char *s) {
 583         struct SocketAddress b;
 584
 585         assert(a);
 586         assert(s);
 587
 588         if (socket_address_parse_netlink(&b, s) < 0)
 589                 return false;
 590
 591         return socket_address_equal(a, &b);
 592 }
 593
 594 bool socket_address_needs_mount(const SocketAddress *a, const char *prefix) {
 595         assert(a);
 596
 597         if (socket_address_family(a) != AF_UNIX)
 598                 return false;
 599
 600         if (a->sockaddr.un.sun_path[0] == 0)
 601                 return false;
 602
 603         return path_startswith(a->sockaddr.un.sun_path, prefix);
 604 }
 605
 606 bool socket_ipv6_is_supported(void) {
 607         char *l = 0;
 608         bool enabled;
 609
 610         if (access("/sys/module/ipv6", F_OK) != 0)
 611                 return 0;
 612
 613         /* If we can't check "disable" parameter, assume enabled */
 614         if (read_one_line_file("/sys/module/ipv6/parameters/disable", &l) < 0)
 615                 return 1;
 616
 617         /* If module was loaded with disable=1 no IPv6 available */
 618         enabled = l[0] == '0';
 619         free(l);
 620
 621         return enabled;
 622 }
 623
 624 static const char* const netlink_family_table[] = {
 625         [NETLINK_ROUTE] = "route",
 626         [NETLINK_FIREWALL] = "firewall",
 627         [NETLINK_INET_DIAG] = "inet-diag",
 628         [NETLINK_NFLOG] = "nflog",
 629         [NETLINK_XFRM] = "xfrm",
 630         [NETLINK_SELINUX] = "selinux",
 631         [NETLINK_ISCSI] = "iscsi",
 632         [NETLINK_AUDIT] = "audit",
 633         [NETLINK_FIB_LOOKUP] = "fib-lookup",
 634         [NETLINK_CONNECTOR] = "connector",
 635         [NETLINK_NETFILTER] = "netfilter",
 636         [NETLINK_IP6_FW] = "ip6-fw",
 637         [NETLINK_DNRTMSG] = "dnrtmsg",
 638         [NETLINK_KOBJECT_UEVENT] = "kobject-uevent",
 639         [NETLINK_GENERIC] = "generic",
 640         [NETLINK_SCSITRANSPORT] = "scsitransport",
 641         [NETLINK_ECRYPTFS] = "ecryptfs"
 642 };
 643
 644 DEFINE_STRING_TABLE_LOOKUP(netlink_family, int);
 645
 646 static const char* const socket_address_bind_ipv6_only_table[_SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX] = {
 647         [SOCKET_ADDRESS_DEFAULT] = "default",
 648         [SOCKET_ADDRESS_BOTH] = "both",
 649         [SOCKET_ADDRESS_IPV6_ONLY] = "ipv6-only"
 650 };
 651
 652 DEFINE_STRING_TABLE_LOOKUP(socket_address_bind_ipv6_only, SocketAddressBindIPv6Only);