src/socket-util.c

   1 /*-*- Mode: C; c-basic-offset: 8 -*-*/
   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
  33 #include "macro.h"
  34 #include "util.h"
  35 #include "socket-util.h"
  36 #include "missing.h"
  37
  38 int socket_address_parse(SocketAddress *a, const char *s) {
  39         int r;
  40         char *e, *n;
  41         unsigned u;
  42
  43         assert(a);
  44         assert(s);
  45
  46         zero(*a);
  47         a->type = SOCK_STREAM;
  48
  49         if (*s == '[') {
  50                 /* IPv6 in [x:.....:z]:p notation */
  51
  52                 if (!(e = strchr(s+1, ']')))
  53                         return -EINVAL;
  54
  55                 if (!(n = strndup(s+1, e-s-1)))
  56                         return -ENOMEM;
  57
  58                 errno = 0;
  59                 if (inet_pton(AF_INET6, n, &a->sockaddr.in6.sin6_addr) <= 0) {
  60                         free(n);
  61                         return errno != 0 ? -errno : -EINVAL;
  62                 }
  63
  64                 free(n);
  65
  66                 e++;
  67                 if (*e != ':')
  68                         return -EINVAL;
  69
  70                 e++;
  71                 if ((r = safe_atou(e, &u)) < 0)
  72                         return r;
  73
  74                 if (u <= 0 || u > 0xFFFF)
  75                         return -EINVAL;
  76
  77                 a->sockaddr.in6.sin6_family = AF_INET6;
  78                 a->sockaddr.in6.sin6_port = htons((uint16_t) u);
  79                 a->size = sizeof(struct sockaddr_in6);
  80
  81         } else if (*s == '/') {
  82                 /* AF_UNIX socket */
  83
  84                 size_t l;
  85
  86                 l = strlen(s);
  87                 if (l >= sizeof(a->sockaddr.un.sun_path))
  88                         return -EINVAL;
  89
  90                 a->sockaddr.un.sun_family = AF_UNIX;
  91                 memcpy(a->sockaddr.un.sun_path, s, l);
  92                 a->size = sizeof(sa_family_t) + l + 1;
  93
  94         } else if (*s == '@') {
  95                 /* Abstract AF_UNIX socket */
  96                 size_t l;
  97
  98                 l = strlen(s+1);
  99                 if (l >= sizeof(a->sockaddr.un.sun_path) - 1)
 100                         return -EINVAL;
 101
 102                 a->sockaddr.un.sun_family = AF_UNIX;
 103                 memcpy(a->sockaddr.un.sun_path+1, s+1, l);
 104                 a->size = sizeof(struct sockaddr_un);
 105
 106         } else {
 107
 108                 if ((e = strchr(s, ':'))) {
 109
 110                         if ((r = safe_atou(e+1, &u)) < 0)
 111                                 return r;
 112
 113                         if (u <= 0 || u > 0xFFFF)
 114                                 return -EINVAL;
 115
 116                         if (!(n = strndup(s, e-s)))
 117                                 return -ENOMEM;
 118
 119                         /* IPv4 in w.x.y.z:p notation? */
 120                         if ((r = inet_pton(AF_INET, n, &a->sockaddr.in4.sin_addr)) < 0) {
 121                                 free(n);
 122                                 return -errno;
 123                         }
 124
 125                         if (r > 0) {
 126                                 /* Gotcha, it's a traditional IPv4 address */
 127                                 free(n);
 128
 129                                 a->sockaddr.in4.sin_family = AF_INET;
 130                                 a->sockaddr.in4.sin_port = htons((uint16_t) u);
 131                                 a->size = sizeof(struct sockaddr_in);
 132                         } else {
 133                                 unsigned idx;
 134
 135                                 if (strlen(n) > IF_NAMESIZE-1) {
 136                                         free(n);
 137                                         return -EINVAL;
 138                                 }
 139
 140                                 /* Uh, our last resort, an interface name */
 141                                 idx = if_nametoindex(n);
 142                                 free(n);
 143
 144                                 if (idx == 0)
 145                                         return -EINVAL;
 146
 147                                 a->sockaddr.in6.sin6_family = AF_INET6;
 148                                 a->sockaddr.in6.sin6_port = htons((uint16_t) u);
 149                                 a->sockaddr.in6.sin6_scope_id = idx;
 150                                 a->sockaddr.in6.sin6_addr = in6addr_any;
 151                                 a->size = sizeof(struct sockaddr_in6);
 152
 153                         }
 154                 } else {
 155
 156                         /* Just a port */
 157                         if ((r = safe_atou(s, &u)) < 0)
 158                                 return r;
 159
 160                         if (u <= 0 || u > 0xFFFF)
 161                                 return -EINVAL;
 162
 163                         a->sockaddr.in6.sin6_family = AF_INET6;
 164                         a->sockaddr.in6.sin6_port = htons((uint16_t) u);
 165                         a->sockaddr.in6.sin6_addr = in6addr_any;
 166                         a->size = sizeof(struct sockaddr_in6);
 167                 }
 168         }
 169
 170         return 0;
 171 }
 172
 173 int socket_address_verify(const SocketAddress *a) {
 174         assert(a);
 175
 176         switch (socket_address_family(a)) {
 177                 case AF_INET:
 178                         if (a->size != sizeof(struct sockaddr_in))
 179                                 return -EINVAL;
 180
 181                         if (a->sockaddr.in4.sin_port == 0)
 182                                 return -EINVAL;
 183
 184                         return 0;
 185
 186                 case AF_INET6:
 187                         if (a->size != sizeof(struct sockaddr_in6))
 188                                 return -EINVAL;
 189
 190                         if (a->sockaddr.in6.sin6_port == 0)
 191                                 return -EINVAL;
 192
 193                         return 0;
 194
 195                 case AF_UNIX:
 196                         if (a->size < sizeof(sa_family_t))
 197                                 return -EINVAL;
 198
 199                         if (a->size > sizeof(sa_family_t)) {
 200
 201                                 if (a->sockaddr.un.sun_path[0] == 0) {
 202                                         /* abstract */
 203                                         if (a->size != sizeof(struct sockaddr_un))
 204                                                 return -EINVAL;
 205                                 } else {
 206                                         char *e;
 207
 208                                         /* path */
 209                                         if (!(e = memchr(a->sockaddr.un.sun_path, 0, sizeof(a->sockaddr.un.sun_path))))
 210                                                 return -EINVAL;
 211
 212                                         if (a->size != sizeof(sa_family_t) + (e - a->sockaddr.un.sun_path) + 1)
 213                                                 return -EINVAL;
 214                                 }
 215                         }
 216
 217                         return 0;
 218
 219                 default:
 220                         return -EAFNOSUPPORT;
 221         }
 222 }
 223
 224 int socket_address_print(const SocketAddress *a, char **p) {
 225         int r;
 226         assert(a);
 227         assert(p);
 228
 229         if ((r = socket_address_verify(a)) < 0)
 230                 return r;
 231
 232         switch (socket_address_family(a)) {
 233                 case AF_INET: {
 234                         char *ret;
 235
 236                         if (!(ret = new(char, INET_ADDRSTRLEN+1+5+1)))
 237                                 return -ENOMEM;
 238
 239                         if (!inet_ntop(AF_INET, &a->sockaddr.in4.sin_addr, ret, INET_ADDRSTRLEN)) {
 240                                 free(ret);
 241                                 return -errno;
 242                         }
 243
 244                         sprintf(strchr(ret, 0), ":%u", ntohs(a->sockaddr.in4.sin_port));
 245                         *p = ret;
 246                         return 0;
 247                 }
 248
 249                 case AF_INET6: {
 250                         char *ret;
 251
 252                         if (!(ret = new(char, 1+INET6_ADDRSTRLEN+2+5+1)))
 253                                 return -ENOMEM;
 254
 255                         ret[0] = '[';
 256                         if (!inet_ntop(AF_INET6, &a->sockaddr.in6.sin6_addr, ret+1, INET6_ADDRSTRLEN)) {
 257                                 free(ret);
 258                                 return -errno;
 259                         }
 260
 261                         sprintf(strchr(ret, 0), "]:%u", ntohs(a->sockaddr.in6.sin6_port));
 262                         *p = ret;
 263                         return 0;
 264                 }
 265
 266                 case AF_UNIX: {
 267                         char *ret;
 268
 269                         if (a->size <= sizeof(sa_family_t)) {
 270
 271                                 if (!(ret = strdup("<unamed>")))
 272                                         return -ENOMEM;
 273
 274                         } else if (a->sockaddr.un.sun_path[0] == 0) {
 275                                 /* abstract */
 276
 277                                 /* FIXME: We assume we can print the
 278                                  * socket path here and that it hasn't
 279                                  * more than one NUL byte. That is
 280                                  * actually an invalid assumption */
 281
 282                                 if (!(ret = new(char, sizeof(a->sockaddr.un.sun_path)+1)))
 283                                         return -ENOMEM;
 284
 285                                 ret[0] = '@';
 286                                 memcpy(ret+1, a->sockaddr.un.sun_path+1, sizeof(a->sockaddr.un.sun_path)-1);
 287                                 ret[sizeof(a->sockaddr.un.sun_path)] = 0;
 288
 289                         } else {
 290
 291                                 if (!(ret = strdup(a->sockaddr.un.sun_path)))
 292                                         return -ENOMEM;
 293                         }
 294
 295                         *p = ret;
 296                         return 0;
 297                 }
 298
 299                 default:
 300                         return -EINVAL;
 301         }
 302 }
 303
 304 int socket_address_listen(
 305                 const SocketAddress *a,
 306                 int backlog,
 307                 SocketAddressBindIPv6Only only,
 308                 const char *bind_to_device,
 309                 bool free_bind,
 310                 mode_t directory_mode,
 311                 mode_t socket_mode,
 312                 int *ret) {
 313
 314         int r, fd, one;
 315         assert(a);
 316         assert(ret);
 317
 318         if ((r = socket_address_verify(a)) < 0)
 319                 return r;
 320
 321         if ((fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)) < 0)
 322                 return -errno;
 323
 324         if (socket_address_family(a) == AF_INET6 && only != SOCKET_ADDRESS_DEFAULT) {
 325                 int flag = only == SOCKET_ADDRESS_IPV6_ONLY;
 326
 327                 if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &flag, sizeof(flag)) < 0)
 328                         goto fail;
 329         }
 330
 331         if (bind_to_device)
 332                 if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, bind_to_device, strlen(bind_to_device)+1) < 0)
 333                         goto fail;
 334
 335         if (free_bind) {
 336                 one = 1;
 337                 if (setsockopt(fd, IPPROTO_IP, IP_FREEBIND, &one, sizeof(one)) < 0)
 338                         log_warning("IP_FREEBIND failed: %m");
 339         }
 340
 341         one = 1;
 342         if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) < 0)
 343                 goto fail;
 344
 345         if (socket_address_family(a) == AF_UNIX && a->sockaddr.un.sun_path[0] != 0) {
 346                 mode_t old_mask;
 347
 348                 /* Create parents */
 349                 mkdir_parents(a->sockaddr.un.sun_path, directory_mode);
 350
 351                 /* Enforce the right access mode for the socket*/
 352                 old_mask = umask(~ socket_mode);
 353
 354                 /* Include the original umask in our mask */
 355                 umask(~socket_mode | old_mask);
 356
 357                 r = bind(fd, &a->sockaddr.sa, a->size);
 358
 359                 if (r < 0 && errno == EADDRINUSE) {
 360                         /* Unlink and try again */
 361                         unlink(a->sockaddr.un.sun_path);
 362                         r = bind(fd, &a->sockaddr.sa, a->size);
 363                 }
 364
 365                 umask(old_mask);
 366         } else
 367                 r = bind(fd, &a->sockaddr.sa, a->size);
 368
 369         if (r < 0)
 370                 goto fail;
 371
 372         if (a->type == SOCK_STREAM)
 373                 if (listen(fd, backlog) < 0)
 374                         goto fail;
 375
 376         *ret = fd;
 377         return 0;
 378
 379 fail:
 380         r = -errno;
 381         close_nointr_nofail(fd);
 382         return r;
 383 }
 384
 385 bool socket_address_can_accept(const SocketAddress *a) {
 386         assert(a);
 387
 388         return
 389                 a->type == SOCK_STREAM ||
 390                 a->type == SOCK_SEQPACKET;
 391 }
 392
 393 bool socket_address_equal(const SocketAddress *a, const SocketAddress *b) {
 394         assert(a);
 395         assert(b);
 396
 397         /* Invalid addresses are unequal to all */
 398         if (socket_address_verify(a) < 0 ||
 399             socket_address_verify(b) < 0)
 400                 return false;
 401
 402         if (a->type != b->type)
 403                 return false;
 404
 405         if (a->size != b->size)
 406                 return false;
 407
 408         if (socket_address_family(a) != socket_address_family(b))
 409                 return false;
 410
 411         switch (socket_address_family(a)) {
 412
 413         case AF_INET:
 414                 if (a->sockaddr.in4.sin_addr.s_addr != b->sockaddr.in4.sin_addr.s_addr)
 415                         return false;
 416
 417                 if (a->sockaddr.in4.sin_port != b->sockaddr.in4.sin_port)
 418                         return false;
 419
 420                 break;
 421
 422         case AF_INET6:
 423                 if (memcmp(&a->sockaddr.in6.sin6_addr, &b->sockaddr.in6.sin6_addr, sizeof(a->sockaddr.in6.sin6_addr)) != 0)
 424                         return false;
 425
 426                 if (a->sockaddr.in6.sin6_port != b->sockaddr.in6.sin6_port)
 427                         return false;
 428
 429                 break;
 430
 431         case AF_UNIX:
 432
 433                 if ((a->sockaddr.un.sun_path[0] == 0) != (b->sockaddr.un.sun_path[0] == 0))
 434                         return false;
 435
 436                 if (a->sockaddr.un.sun_path[0]) {
 437                         if (strncmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, sizeof(a->sockaddr.un.sun_path)) != 0)
 438                                 return false;
 439                 } else {
 440                         if (memcmp(a->sockaddr.un.sun_path, b->sockaddr.un.sun_path, sizeof(a->sockaddr.un.sun_path)) != 0)
 441                                 return false;
 442                 }
 443
 444                 break;
 445
 446         default:
 447                 /* Cannot compare, so we assume the addresses are different */
 448                 return false;
 449         }
 450
 451         return true;
 452 }
 453
 454 bool socket_address_is(const SocketAddress *a, const char *s, int type) {
 455         struct SocketAddress b;
 456
 457         assert(a);
 458         assert(s);
 459
 460         if (socket_address_parse(&b, s) < 0)
 461                 return false;
 462
 463         b.type = type;
 464
 465         return socket_address_equal(a, &b);
 466 }
 467
 468 bool socket_address_needs_mount(const SocketAddress *a, const char *prefix) {
 469         assert(a);
 470
 471         if (socket_address_family(a) != AF_UNIX)
 472                 return false;
 473
 474         if (a->sockaddr.un.sun_path[0] == 0)
 475                 return false;
 476
 477         return path_startswith(a->sockaddr.un.sun_path, prefix);
 478 }
 479
 480 static const char* const socket_address_bind_ipv6_only_table[_SOCKET_ADDRESS_BIND_IPV6_ONLY_MAX] = {
 481         [SOCKET_ADDRESS_DEFAULT] = "default",
 482         [SOCKET_ADDRESS_BOTH] = "both",
 483         [SOCKET_ADDRESS_IPV6_ONLY] = "ipv6-only"
 484 };
 485
 486 DEFINE_STRING_TABLE_LOOKUP(socket_address_bind_ipv6_only, SocketAddressBindIPv6Only);