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