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_verify(const SocketAddress *a) {
 193         assert(a);
 194
 195         switch (socket_address_family(a)) {
 196                 case AF_INET:
 197                         if (a->size != sizeof(struct sockaddr_in))
 198                                 return -EINVAL;
 199
 200                         if (a->sockaddr.in4.sin_port == 0)
 201                                 return -EINVAL;
 202
 203                         return 0;
 204
 205                 case AF_INET6:
 206                         if (a->size != sizeof(struct sockaddr_in6))
 207                                 return -EINVAL;
 208
 209                         if (a->sockaddr.in6.sin6_port == 0)
 210                                 return -EINVAL;
 211
 212                         return 0;
 213
 214                 case AF_UNIX:
 215                         if (a->size < offsetof(struct sockaddr_un, sun_path))
 216                                 return -EINVAL;
 217
 218                         if (a->size > offsetof(struct sockaddr_un, sun_path)) {
 219
 220                                 if (a->sockaddr.un.sun_path[0] != 0) {
 221                                         char *e;
 222
 223                                         /* path */
 224                                         if (!(e = memchr(a->sockaddr.un.sun_path, 0, sizeof(a->sockaddr.un.sun_path))))
 225                                                 return -EINVAL;
 226
 227                                         if (a->size != offsetof(struct sockaddr_un, sun_path) + (e - a->sockaddr.un.sun_path) + 1)
 228                                                 return -EINVAL;
 229                                 }
 230                         }
 231
 232                         return 0;
 233
 234                 default:
 235                         return -EAFNOSUPPORT;
 236         }
 237 }
 238
 239 int socket_address_print(const SocketAddress *a, char **p) {
 240         int r;
 241         assert(a);
 242         assert(p);
 243
 244         if ((r = socket_address_verify(a)) < 0)
 245                 return r;
 246
 247         switch (socket_address_family(a)) {
 248                 case AF_INET: {
 249                         char *ret;
 250
 251                         if (!(ret = new(char, INET_ADDRSTRLEN+1+5+1)))
 252                                 return -ENOMEM;
 253
 254                         if (!inet_ntop(AF_INET, &a->sockaddr.in4.sin_addr, ret, INET_ADDRSTRLEN)) {
 255                                 free(ret);
 256                                 return -errno;
 257                         }
 258
 259                         sprintf(strchr(ret, 0), ":%u", ntohs(a->sockaddr.in4.sin_port));
 260                         *p = ret;
 261                         return 0;
 262                 }
 263
 264                 case AF_INET6: {
 265                         char *ret;
 266
 267                         if (!(ret = new(char, 1+INET6_ADDRSTRLEN+2+5+1)))
 268                                 return -ENOMEM;
 269
 270                         ret[0] = '[';
 271                         if (!inet_ntop(AF_INET6, &a->sockaddr.in6.sin6_addr, ret+1, INET6_ADDRSTRLEN)) {
 272                                 free(ret);
 273                                 return -errno;
 274                         }
 275
 276                         sprintf(strchr(ret, 0), "]:%u", ntohs(a->sockaddr.in6.sin6_port));
 277                         *p = ret;
 278                         return 0;
 279                 }
 280
 281                 case AF_UNIX: {
 282                         char *ret;
 283
 284                         if (a->size <= offsetof(struct sockaddr_un, sun_path)) {
 285
 286                                 if (!(ret = strdup("<unamed>")))
 287                                         return -ENOMEM;
 288
 289                         } else if (a->sockaddr.un.sun_path[0] == 0) {
 290                                 /* abstract */
 291
 292                                 /* FIXME: We assume we can print the
 293                                  * socket path here and that it hasn't
 294                                  * more than one NUL byte. That is
 295                                  * actually an invalid assumption */
 296
 297                                 if (!(ret = new(char, sizeof(a->sockaddr.un.sun_path)+1)))
 298                                         return -ENOMEM;
 299
 300                                 ret[0] = '@';
 301                                 memcpy(ret+1, a->sockaddr.un.sun_path+1, sizeof(a->sockaddr.un.sun_path)-1);
 302                                 ret[sizeof(a->sockaddr.un.sun_path)] = 0;
 303
 304                         } else {
 305
 306                                 if (!(ret = strdup(a->sockaddr.un.sun_path)))
 307                                         return -ENOMEM;
 308                         }
 309
 310                         *p = ret;
 311                         return 0;
 312                 }
 313
 314                 default:
 315                         return -EINVAL;
 316         }
 317 }
 318
 319 int socket_address_listen(
 320                 const SocketAddress *a,
 321                 int backlog,
 322                 SocketAddressBindIPv6Only only,
 323                 const char *bind_to_device,
 324                 bool free_bind,
 325                 mode_t directory_mode,
 326                 mode_t socket_mode,
 327                 const char *label,
 328                 int *ret) {
 329
 330         int r, fd, one;
 331         assert(a);
 332         assert(ret);
 333
 334         if ((r = socket_address_verify(a)) < 0)
 335                 return r;
 336
 337         if (socket_address_family(a) == AF_INET6 && !socket_ipv6_is_supported())
 338                 return -EAFNOSUPPORT;
 339
 340         r = label_socket_set(label);
 341         if (r < 0)
 342                 return r;
 343
 344         fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
 345         r = fd < 0 ? -errno : 0;
 346
 347         label_socket_clear();
 348
 349         if (r < 0)
 350                 return r;
 351
 352         if (socket_address_family(a) == AF_INET6 && only != SOCKET_ADDRESS_DEFAULT) {
 353                 int flag = only == SOCKET_ADDRESS_IPV6_ONLY;
 354
 355                 if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &flag, sizeof(flag)) < 0)
 356                         goto fail;
 357         }
 358
 359         if (bind_to_device)
 360                 if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, bind_to_device, strlen(bind_to_device)+1) < 0)
 361                         goto fail;
 362
 363         if (free_bind) {
 364                 one = 1;
 365                 if (setsockopt(fd, IPPROTO_IP, IP_FREEBIND, &one, sizeof(one)) < 0)
 366                         log_warning("IP_FREEBIND failed: %m");
 367         }
 368
 369         one = 1;
 370         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0)
 371                 goto fail;
 372
 373         if (socket_address_family(a) == AF_UNIX && a->sockaddr.un.sun_path[0] != 0) {
 374                 mode_t old_mask;
 375
 376                 /* Create parents */
 377                 mkdir_parents(a->sockaddr.un.sun_path, directory_mode);
 378
 379                 /* Enforce the right access mode for the socket*/
 380                 old_mask = umask(~ socket_mode);
 381
 382                 /* Include the original umask in our mask */
 383                 umask(~socket_mode | old_mask);
 384
 385                 r = bind(fd, &a->sockaddr.sa, a->size);
 386
 387                 if (r < 0 && errno == EADDRINUSE) {
 388                         /* Unlink and try again */
 389                         unlink(a->sockaddr.un.sun_path);
 390                         r = bind(fd, &a->sockaddr.sa, a->size);
 391                 }
 392
 393                 umask(old_mask);
 394         } else
 395                 r = bind(fd, &a->sockaddr.sa, a->size);
 396
 397         if (r < 0)
 398                 goto fail;
 399
 400         if (a->type == SOCK_STREAM)
 401                 if (listen(fd, backlog) < 0)
 402                         goto fail;
 403
 404         *ret = fd;
 405         return 0;
 406
 407 fail:
 408         r = -errno;
 409         close_nointr_nofail(fd);
 410         return r;
 411 }
 412
 413 bool socket_address_can_accept(const SocketAddress *a) {
 414         assert(a);
 415
 416         return
 417                 a->type == SOCK_STREAM ||
 418                 a->type == SOCK_SEQPACKET;
 419 }
 420
 421 bool socket_address_equal(const SocketAddress *a, const SocketAddress *b) {
 422         assert(a);
 423         assert(b);
 424
 425         /* Invalid addresses are unequal to all */
 426         if (socket_address_verify(a) < 0 ||
 427             socket_address_verify(b) < 0)
 428                 return false;
 429
 430         if (a->type != b->type)
 431                 return false;
 432
 433         if (a->size != b->size)
 434                 return false;
 435
 436         if (socket_address_family(a) != socket_address_family(b))
 437                 return false;
 438
 439         switch (socket_address_family(a)) {
 440
 441         case AF_INET:
 442                 if (a->sockaddr.in4.sin_addr.s_addr != b->sockaddr.in4.sin_addr.s_addr)
 443                         return false;
 444
 445                 if (a->sockaddr.in4.sin_port != b->sockaddr.in4.sin_port)
 446                         return false;
 447
 448                 break;
 449
 450         case AF_INET6:
 451                 if (memcmp(&a->sockaddr.in6.sin6_addr, &b->sockaddr.in6.sin6_addr, sizeof(a->sockaddr.in6.sin6_addr)) != 0)
 452                         return false;
 453
 454                 if (a->sockaddr.in6.sin6_port != b->sockaddr.in6.sin6_port)
 455                         return false;
 456
 457                 break;
 458
 459         case AF_UNIX:
 460
 461                 if ((a->sockaddr.un.sun_path[0] == 0) != (b->sockaddr.un.sun_path[0] == 0))
 462                         return false;
 463
 464                 if (a->sockaddr.un.sun_path[0]) {
 465                         if (strncmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, sizeof(a->sockaddr.un.sun_path)) != 0)
 466                                 return false;
 467                 } else {
 468                         if (memcmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, a->size) != 0)
 469                                 return false;
 470                 }
 471
 472                 break;
 473
 474         default:
 475                 /* Cannot compare, so we assume the addresses are different */
 476                 return false;
 477         }
 478
 479         return true;
 480 }
 481
 482 bool socket_address_is(const SocketAddress *a, const char *s, int type) {
 483         struct SocketAddress b;
 484
 485         assert(a);
 486         assert(s);
 487
 488         if (socket_address_parse(&b, s) < 0)
 489                 return false;
 490
 491         b.type = type;
 492
 493         return socket_address_equal(a, &b);
 494 }
 495
 496 bool socket_address_needs_mount(const SocketAddress *a, const char *prefix) {
 497         assert(a);
 498
 499         if (socket_address_family(a) != AF_UNIX)
 500                 return false;
 501
 502         if (a->sockaddr.un.sun_path[0] == 0)
 503                 return false;
 504
 505         return path_startswith(a->sockaddr.un.sun_path, prefix);
 506 }
 507
 508 bool socket_ipv6_is_supported(void) {
 509         char *l = 0;
 510         bool enabled;
 511
 512         if (access("/sys/module/ipv6", F_OK) != 0)
 513                 return 0;
 514
 515         /* If we can't check "disable" parameter, assume enabled */
 516         if (read_one_line_file("/sys/module/ipv6/parameters/disable", &l) < 0)
 517                 return 1;
 518
 519         /* If module was loaded with disable=1 no IPv6 available */
 520         enabled = l[0] == '0';
 521         free(l);
 522
 523         return enabled;
 524 }
 525
 526 static const char* const socket_address_bind_ipv6_only_table[_SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX] = {
 527         [SOCKET_ADDRESS_DEFAULT] = "default",
 528         [SOCKET_ADDRESS_BOTH] = "both",
 529         [SOCKET_ADDRESS_IPV6_ONLY] = "ipv6-only"
 530 };
 531
 532 DEFINE_STRING_TABLE_LOOKUP(socket_address_bind_ipv6_only, SocketAddressBindIPv6Only);