release/src/router/dropbear/netio.c

   1 #include "netio.h"
   2 #include "list.h"
   3 #include "dbutil.h"
   4 #include "session.h"
   5 #include "debug.h"
   6
   7 struct dropbear_progress_connection {
   8         struct addrinfo *res;
   9         struct addrinfo *res_iter;
  10
  11         char *remotehost, *remoteport; /* For error reporting */
  12
  13         connect_callback cb;
  14         void *cb_data;
  15
  16         struct Queue *writequeue; /* A queue of encrypted packets to send with TCP fastopen,
  17                                                                 or NULL. */
  18
  19         int sock;
  20
  21         char* errstring;
  22 };
  23
  24 /* Deallocate a progress connection. Removes from the pending list if iter!=NULL.
  25 Does not close sockets */
  26 static void remove_connect(struct dropbear_progress_connection *c, m_list_elem *iter) {
  27         if (c->res) {
  28                 freeaddrinfo(c->res);
  29         }
  30         m_free(c->remotehost);
  31         m_free(c->remoteport);
  32         m_free(c->errstring);
  33         m_free(c);
  34
  35         if (iter) {
  36                 list_remove(iter);
  37         }
  38 }
  39
  40 static void cancel_callback(int result, int sock, void* UNUSED(data), const char* UNUSED(errstring)) {
  41         if (result == DROPBEAR_SUCCESS)
  42         {
  43                 m_close(sock);
  44         }
  45 }
  46
  47 void cancel_connect(struct dropbear_progress_connection *c) {
  48         c->cb = cancel_callback;
  49         c->cb_data = NULL;
  50 }
  51
  52 static void connect_try_next(struct dropbear_progress_connection *c) {
  53         struct addrinfo *r;
  54         int res = 0;
  55         int fastopen = 0;
  56 #ifdef DROPBEAR_CLIENT_TCP_FAST_OPEN
  57         struct msghdr message;
  58 #endif
  59
  60         for (r = c->res_iter; r; r = r->ai_next)
  61         {
  62                 dropbear_assert(c->sock == -1);
  63
  64                 c->sock = socket(c->res_iter->ai_family, c->res_iter->ai_socktype, c->res_iter->ai_protocol);
  65                 if (c->sock < 0) {
  66                         continue;
  67                 }
  68
  69                 ses.maxfd = MAX(ses.maxfd, c->sock);
  70                 set_sock_nodelay(c->sock);
  71                 setnonblocking(c->sock);
  72
  73 #ifdef DROPBEAR_CLIENT_TCP_FAST_OPEN
  74                 fastopen = (c->writequeue != NULL);
  75
  76                 if (fastopen) {
  77                         memset(&message, 0x0, sizeof(message));
  78                         message.msg_name = r->ai_addr;
  79                         message.msg_namelen = r->ai_addrlen;
  80                         /* 6 is arbitrary, enough to hold initial packets */
  81                         unsigned int iovlen = 6; /* Linux msg_iovlen is a size_t */
  82                         struct iovec iov[6];
  83                         packet_queue_to_iovec(c->writequeue, iov, &iovlen);
  84                         message.msg_iov = iov;
  85                         message.msg_iovlen = iovlen;
  86                         res = sendmsg(c->sock, &message, MSG_FASTOPEN);
  87                         /* Returns EINPROGRESS if FASTOPEN wasn't available */
  88                         if (res < 0) {
  89                                 if (errno != EINPROGRESS) {
  90                                         m_free(c->errstring);
  91                                         c->errstring = m_strdup(strerror(errno));
  92                                         /* Not entirely sure which kind of errors are normal - 2.6.32 seems to
  93                                         return EPIPE for any (nonblocking?) sendmsg(). just fall back */
  94                                         TRACE(("sendmsg tcp_fastopen failed, falling back. %s", strerror(errno)));
  95                                         /* No kernel MSG_FASTOPEN support. Fall back below */
  96                                         fastopen = 0;
  97                                         /* Set to NULL to avoid trying again */
  98                                         c->writequeue = NULL;
  99                                 }
 100                         } else {
 101                                 packet_queue_consume(c->writequeue, res);
 102                         }
 103                 }
 104 #endif
 105
 106                 /* Normal connect(), used as fallback for TCP fastopen too */
 107                 if (!fastopen) {
 108                         res = connect(c->sock, r->ai_addr, r->ai_addrlen);
 109                 }
 110
 111                 if (res < 0 && errno != EINPROGRESS) {
 112                         /* failure */
 113                         m_free(c->errstring);
 114                         c->errstring = m_strdup(strerror(errno));
 115                         close(c->sock);
 116                         c->sock = -1;
 117                         continue;
 118                 } else {
 119                         /* new connection was successful, wait for it to complete */
 120                         break;
 121                 }
 122         }
 123
 124         if (r) {
 125                 c->res_iter = r->ai_next;
 126         } else {
 127                 c->res_iter = NULL;
 128         }
 129 }
 130
 131 /* Connect via TCP to a host. */
 132 struct dropbear_progress_connection *connect_remote(const char* remotehost, const char* remoteport,
 133         connect_callback cb, void* cb_data)
 134 {
 135         struct dropbear_progress_connection *c = NULL;
 136         int err;
 137         struct addrinfo hints;
 138
 139         c = m_malloc(sizeof(*c));
 140         c->remotehost = m_strdup(remotehost);
 141         c->remoteport = m_strdup(remoteport);
 142         c->sock = -1;
 143         c->cb = cb;
 144         c->cb_data = cb_data;
 145
 146         list_append(&ses.conn_pending, c);
 147
 148         memset(&hints, 0, sizeof(hints));
 149         hints.ai_socktype = SOCK_STREAM;
 150         hints.ai_family = AF_UNSPEC;
 151
 152         err = getaddrinfo(remotehost, remoteport, &hints, &c->res);
 153         if (err) {
 154                 int len;
 155                 len = 100 + strlen(gai_strerror(err));
 156                 c->errstring = (char*)m_malloc(len);
 157                 snprintf(c->errstring, len, "Error resolving '%s' port '%s'. %s",
 158                                 remotehost, remoteport, gai_strerror(err));
 159                 TRACE(("Error resolving: %s", gai_strerror(err)))
 160         } else {
 161                 c->res_iter = c->res;
 162         }
 163
 164         return c;
 165 }
 166
 167 void remove_connect_pending() {
 168         while (ses.conn_pending.first) {
 169                 struct dropbear_progress_connection *c = ses.conn_pending.first->item;
 170                 remove_connect(c, ses.conn_pending.first);
 171         }
 172 }
 173
 174
 175 void set_connect_fds(fd_set *writefd) {
 176         m_list_elem *iter;
 177         TRACE(("enter set_connect_fds"))
 178         iter = ses.conn_pending.first;
 179         while (iter) {
 180                 m_list_elem *next_iter = iter->next;
 181                 struct dropbear_progress_connection *c = iter->item;
 182                 /* Set one going */
 183                 while (c->res_iter && c->sock < 0) {
 184                         connect_try_next(c);
 185                 }
 186                 if (c->sock >= 0) {
 187                         FD_SET(c->sock, writefd);
 188                 } else {
 189                         /* Final failure */
 190                         if (!c->errstring) {
 191                                 c->errstring = m_strdup("unexpected failure");
 192                         }
 193                         c->cb(DROPBEAR_FAILURE, -1, c->cb_data, c->errstring);
 194                         remove_connect(c, iter);
 195                 }
 196                 iter = next_iter;
 197         }
 198 }
 199
 200 void handle_connect_fds(fd_set *writefd) {
 201         m_list_elem *iter;
 202         TRACE(("enter handle_connect_fds"))
 203         for (iter = ses.conn_pending.first; iter; iter = iter->next) {
 204                 int val;
 205                 socklen_t vallen = sizeof(val);
 206                 struct dropbear_progress_connection *c = iter->item;
 207
 208                 if (c->sock < 0 || !FD_ISSET(c->sock, writefd)) {
 209                         continue;
 210                 }
 211
 212                 TRACE(("handling %s port %s socket %d", c->remotehost, c->remoteport, c->sock));
 213
 214                 if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &val, &vallen) != 0) {
 215                         TRACE(("handle_connect_fds getsockopt(%d) SO_ERROR failed: %s", c->sock, strerror(errno)))
 216                         /* This isn't expected to happen - Unix has surprises though, continue gracefully. */
 217                         m_close(c->sock);
 218                         c->sock = -1;
 219                 } else if (val != 0) {
 220                         /* Connect failed */
 221                         TRACE(("connect to %s port %s failed.", c->remotehost, c->remoteport))
 222                         m_close(c->sock);
 223                         c->sock = -1;
 224
 225                         m_free(c->errstring);
 226                         c->errstring = m_strdup(strerror(val));
 227                 } else {
 228                         /* New connection has been established */
 229                         c->cb(DROPBEAR_SUCCESS, c->sock, c->cb_data, NULL);
 230                         remove_connect(c, iter);
 231                         TRACE(("leave handle_connect_fds - success"))
 232                         /* Must return here - remove_connect() invalidates iter */
 233                         return;
 234                 }
 235         }
 236         TRACE(("leave handle_connect_fds - end iter"))
 237 }
 238
 239 void connect_set_writequeue(struct dropbear_progress_connection *c, struct Queue *writequeue) {
 240         c->writequeue = writequeue;
 241 }
 242
 243 void packet_queue_to_iovec(struct Queue *queue, struct iovec *iov, unsigned int *iov_count) {
 244         struct Link *l;
 245         unsigned int i;
 246         int len;
 247         buffer *writebuf;
 248
 249         #ifndef IOV_MAX
 250         #define IOV_MAX UIO_MAXIOV
 251         #endif
 252
 253         *iov_count = MIN(MIN(queue->count, IOV_MAX), *iov_count);
 254
 255         for (l = queue->head, i = 0; i < *iov_count; l = l->link, i++)
 256         {
 257                 writebuf = (buffer*)l->item;
 258                 len = writebuf->len - 1 - writebuf->pos;
 259                 dropbear_assert(len > 0);
 260                 TRACE2(("write_packet writev #%d  type %d len %d/%d", i, writebuf->data[writebuf->len-1],
 261                                 len, writebuf->len-1))
 262                 iov[i].iov_base = buf_getptr(writebuf, len);
 263                 iov[i].iov_len = len;
 264         }
 265 }
 266
 267 void packet_queue_consume(struct Queue *queue, ssize_t written) {
 268         buffer *writebuf;
 269         int len;
 270         while (written > 0) {
 271                 writebuf = (buffer*)examine(queue);
 272                 len = writebuf->len - 1 - writebuf->pos;
 273                 if (len > written) {
 274                         /* partial buffer write */
 275                         buf_incrpos(writebuf, written);
 276                         written = 0;
 277                 } else {
 278                         written -= len;
 279                         dequeue(queue);
 280                         buf_free(writebuf);
 281                 }
 282         }
 283 }
 284
 285 void set_sock_nodelay(int sock) {
 286         int val;
 287
 288         /* disable nagle */
 289         val = 1;
 290         setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void*)&val, sizeof(val));
 291 }
 292
 293 #ifdef DROPBEAR_SERVER_TCP_FAST_OPEN
 294 void set_listen_fast_open(int sock) {
 295         int qlen = MAX(MAX_UNAUTH_PER_IP, 5);
 296         if (setsockopt(sock, SOL_TCP, TCP_FASTOPEN, &qlen, sizeof(qlen)) != 0) {
 297                 TRACE(("set_listen_fast_open failed for socket %d: %s", sock, strerror(errno)))
 298         }
 299 }
 300
 301 #endif
 302
 303 void set_sock_priority(int sock, enum dropbear_prio prio) {
 304
 305         int rc;
 306 #ifdef IPTOS_LOWDELAY
 307         int iptos_val = 0;
 308 #endif
 309 #ifdef SO_PRIORITY
 310         int so_prio_val = 0;
 311 #endif
 312
 313
 314         /* Don't log ENOTSOCK errors so that this can harmlessly be called
 315          * on a client '-J' proxy pipe */
 316
 317         /* set the TOS bit for either ipv4 or ipv6 */
 318 #ifdef IPTOS_LOWDELAY
 319         if (prio == DROPBEAR_PRIO_LOWDELAY) {
 320                 iptos_val = IPTOS_LOWDELAY;
 321         } else if (prio == DROPBEAR_PRIO_BULK) {
 322                 iptos_val = IPTOS_THROUGHPUT;
 323         }
 324 #if defined(IPPROTO_IPV6) && defined(IPV6_TCLASS)
 325         rc = setsockopt(sock, IPPROTO_IPV6, IPV6_TCLASS, (void*)&iptos_val, sizeof(iptos_val));
 326         if (rc < 0 && errno != ENOTSOCK) {
 327                 TRACE(("Couldn't set IPV6_TCLASS (%s)", strerror(errno)));
 328         }
 329 #endif
 330         rc = setsockopt(sock, IPPROTO_IP, IP_TOS, (void*)&iptos_val, sizeof(iptos_val));
 331         if (rc < 0 && errno != ENOTSOCK) {
 332                 TRACE(("Couldn't set IP_TOS (%s)", strerror(errno)));
 333         }
 334 #endif
 335
 336 #ifdef SO_PRIORITY
 337         if (prio == DROPBEAR_PRIO_LOWDELAY) {
 338                 so_prio_val = TC_PRIO_INTERACTIVE;
 339         } else if (prio == DROPBEAR_PRIO_BULK) {
 340                 so_prio_val = TC_PRIO_BULK;
 341         }
 342         /* linux specific, sets QoS class. see tc-prio(8) */
 343         rc = setsockopt(sock, SOL_SOCKET, SO_PRIORITY, (void*) &so_prio_val, sizeof(so_prio_val));
 344         if (rc < 0 && errno != ENOTSOCK)
 345                 dropbear_log(LOG_WARNING, "Couldn't set SO_PRIORITY (%s)",
 346                                 strerror(errno));
 347 #endif
 348
 349 }
 350
 351 /* Listen on address:port.
 352  * Special cases are address of "" listening on everything,
 353  * and address of NULL listening on localhost only.
 354  * Returns the number of sockets bound on success, or -1 on failure. On
 355  * failure, if errstring wasn't NULL, it'll be a newly malloced error
 356  * string.*/
 357 int dropbear_listen(const char* address, const char* port,
 358                 int *socks, unsigned int sockcount, char **errstring, int *maxfd) {
 359
 360         struct addrinfo hints, *res = NULL, *res0 = NULL;
 361         int err;
 362         unsigned int nsock;
 363         struct linger linger;
 364         int val;
 365         int sock;
 366
 367         TRACE(("enter dropbear_listen"))
 368
 369         memset(&hints, 0, sizeof(hints));
 370         hints.ai_family = AF_UNSPEC; /* TODO: let them flag v4 only etc */
 371         hints.ai_socktype = SOCK_STREAM;
 372
 373         /* for calling getaddrinfo:
 374          address == NULL and !AI_PASSIVE: local loopback
 375          address == NULL and AI_PASSIVE: all interfaces
 376          address != NULL: whatever the address says */
 377         if (!address) {
 378                 TRACE(("dropbear_listen: local loopback"))
 379         } else {
 380                 if (address[0] == '\0') {
 381                         TRACE(("dropbear_listen: all interfaces"))
 382                         address = NULL;
 383                 }
 384                 hints.ai_flags = AI_PASSIVE;
 385         }
 386         err = getaddrinfo(address, port, &hints, &res0);
 387
 388         if (err) {
 389                 if (errstring != NULL && *errstring == NULL) {
 390                         int len;
 391                         len = 20 + strlen(gai_strerror(err));
 392                         *errstring = (char*)m_malloc(len);
 393                         snprintf(*errstring, len, "Error resolving: %s", gai_strerror(err));
 394                 }
 395                 if (res0) {
 396                         freeaddrinfo(res0);
 397                         res0 = NULL;
 398                 }
 399                 TRACE(("leave dropbear_listen: failed resolving"))
 400                 return -1;
 401         }
 402
 403
 404         nsock = 0;
 405         for (res = res0; res != NULL && nsock < sockcount;
 406                         res = res->ai_next) {
 407
 408                 /* Get a socket */
 409                 socks[nsock] = socket(res->ai_family, res->ai_socktype,
 410                                 res->ai_protocol);
 411
 412                 sock = socks[nsock]; /* For clarity */
 413
 414                 if (sock < 0) {
 415                         err = errno;
 416                         TRACE(("socket() failed"))
 417                         continue;
 418                 }
 419
 420                 /* Various useful socket options */
 421                 val = 1;
 422                 /* set to reuse, quick timeout */
 423                 setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &val, sizeof(val));
 424                 linger.l_onoff = 1;
 425                 linger.l_linger = 5;
 426                 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void*)&linger, sizeof(linger));
 427
 428 #if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
 429                 if (res->ai_family == AF_INET6) {
 430                         int on = 1;
 431                         if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY,
 432                                                 &on, sizeof(on)) == -1) {
 433                                 dropbear_log(LOG_WARNING, "Couldn't set IPV6_V6ONLY");
 434                         }
 435                 }
 436 #endif
 437
 438                 set_sock_nodelay(sock);
 439
 440                 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
 441                         err = errno;
 442                         close(sock);
 443                         TRACE(("bind(%s) failed", port))
 444                         continue;
 445                 }
 446
 447                 if (listen(sock, DROPBEAR_LISTEN_BACKLOG) < 0) {
 448                         err = errno;
 449                         close(sock);
 450                         TRACE(("listen() failed"))
 451                         continue;
 452                 }
 453
 454                 *maxfd = MAX(*maxfd, sock);
 455
 456                 nsock++;
 457         }
 458
 459         if (res0) {
 460                 freeaddrinfo(res0);
 461                 res0 = NULL;
 462         }
 463
 464         if (nsock == 0) {
 465                 if (errstring != NULL && *errstring == NULL) {
 466                         int len;
 467                         len = 20 + strlen(strerror(err));
 468                         *errstring = (char*)m_malloc(len);
 469                         snprintf(*errstring, len, "Error listening: %s", strerror(err));
 470                 }
 471                 TRACE(("leave dropbear_listen: failure, %s", strerror(err)))
 472                 return -1;
 473         }
 474
 475         TRACE(("leave dropbear_listen: success, %d socks bound", nsock))
 476         return nsock;
 477 }
 478
 479 void get_socket_address(int fd, char **local_host, char **local_port,
 480                                                 char **remote_host, char **remote_port, int host_lookup)
 481 {
 482         struct sockaddr_storage addr;
 483         socklen_t addrlen;
 484
 485         if (local_host || local_port) {
 486                 addrlen = sizeof(addr);
 487                 if (getsockname(fd, (struct sockaddr*)&addr, &addrlen) < 0) {
 488                         dropbear_exit("Failed socket address: %s", strerror(errno));
 489                 }
 490                 getaddrstring(&addr, local_host, local_port, host_lookup);
 491         }
 492         if (remote_host || remote_port) {
 493                 addrlen = sizeof(addr);
 494                 if (getpeername(fd, (struct sockaddr*)&addr, &addrlen) < 0) {
 495                         dropbear_exit("Failed socket address: %s", strerror(errno));
 496                 }
 497                 getaddrstring(&addr, remote_host, remote_port, host_lookup);
 498         }
 499 }
 500
 501 /* Return a string representation of the socket address passed. The return
 502  * value is allocated with malloc() */
 503 void getaddrstring(struct sockaddr_storage* addr,
 504                         char **ret_host, char **ret_port,
 505                         int host_lookup) {
 506
 507         char host[NI_MAXHOST+1], serv[NI_MAXSERV+1];
 508         unsigned int len;
 509         int ret;
 510
 511         int flags = NI_NUMERICSERV | NI_NUMERICHOST;
 512
 513 #ifndef DO_HOST_LOOKUP
 514         host_lookup = 0;
 515 #endif
 516
 517         if (host_lookup) {
 518                 flags = NI_NUMERICSERV;
 519         }
 520
 521         len = sizeof(struct sockaddr_storage);
 522         /* Some platforms such as Solaris 8 require that len is the length
 523          * of the specific structure. Some older linux systems (glibc 2.1.3
 524          * such as debian potato) have sockaddr_storage.__ss_family instead
 525          * but we'll ignore them */
 526 #ifdef HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY
 527         if (addr->ss_family == AF_INET) {
 528                 len = sizeof(struct sockaddr_in);
 529         }
 530 #ifdef AF_INET6
 531         if (addr->ss_family == AF_INET6) {
 532                 len = sizeof(struct sockaddr_in6);
 533         }
 534 #endif
 535 #endif
 536
 537         ret = getnameinfo((struct sockaddr*)addr, len, host, sizeof(host)-1,
 538                         serv, sizeof(serv)-1, flags);
 539
 540         if (ret != 0) {
 541                 if (host_lookup) {
 542                         /* On some systems (Darwin does it) we get EINTR from getnameinfo
 543                          * somehow. Eew. So we'll just return the IP, since that doesn't seem
 544                          * to exhibit that behaviour. */
 545                         getaddrstring(addr, ret_host, ret_port, 0);
 546                         return;
 547                 } else {
 548                         /* if we can't do a numeric lookup, something's gone terribly wrong */
 549                         dropbear_exit("Failed lookup: %s", gai_strerror(ret));
 550                 }
 551         }
 552
 553         if (ret_host) {
 554                 *ret_host = m_strdup(host);
 555         }
 556         if (ret_port) {
 557                 *ret_port = m_strdup(serv);
 558         }
 559 }
 560