lib/stream.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <config.h>
  18 #include "stream-provider.h"
  19 #include <assert.h>
  20 #include <errno.h>
  21 #include <inttypes.h>
  22 #include <netinet/in.h>
  23 #include <poll.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include "coverage.h"
  27 #include "dynamic-string.h"
  28 #include "flow.h"
  29 #include "ofp-print.h"
  30 #include "ofpbuf.h"
  31 #include "openflow/nicira-ext.h"
  32 #include "openflow/openflow.h"
  33 #include "packets.h"
  34 #include "poll-loop.h"
  35 #include "random.h"
  36 #include "util.h"
  37
  38 #define THIS_MODULE VLM_stream
  39 #include "vlog.h"
  40
  41 /* State of an active stream.*/
  42 enum stream_state {
  43     SCS_CONNECTING,             /* Underlying stream is not connected. */
  44     SCS_CONNECTED,              /* Connection established. */
  45     SCS_DISCONNECTED            /* Connection failed or connection closed. */
  46 };
  47
  48 static struct stream_class *stream_classes[] = {
  49     &tcp_stream_class,
  50     &unix_stream_class,
  51 #ifdef HAVE_OPENSSL
  52     &ssl_stream_class,
  53 #endif
  54 };
  55
  56 static struct pstream_class *pstream_classes[] = {
  57     &ptcp_pstream_class,
  58     &punix_pstream_class,
  59 #ifdef HAVE_OPENSSL
  60     &pssl_pstream_class,
  61 #endif
  62 };
  63
  64 /* Check the validity of the stream class structures. */
  65 static void
  66 check_stream_classes(void)
  67 {
  68 #ifndef NDEBUG
  69     size_t i;
  70
  71     for (i = 0; i < ARRAY_SIZE(stream_classes); i++) {
  72         struct stream_class *class = stream_classes[i];
  73         assert(class->name != NULL);
  74         assert(class->open != NULL);
  75         if (class->close || class->recv || class->send || class->run
  76             || class->run_wait || class->wait) {
  77             assert(class->close != NULL);
  78             assert(class->recv != NULL);
  79             assert(class->send != NULL);
  80             assert(class->wait != NULL);
  81         } else {
  82             /* This class delegates to another one. */
  83         }
  84     }
  85
  86     for (i = 0; i < ARRAY_SIZE(pstream_classes); i++) {
  87         struct pstream_class *class = pstream_classes[i];
  88         assert(class->name != NULL);
  89         assert(class->listen != NULL);
  90         if (class->close || class->accept || class->wait) {
  91             assert(class->close != NULL);
  92             assert(class->accept != NULL);
  93             assert(class->wait != NULL);
  94         } else {
  95             /* This class delegates to another one. */
  96         }
  97     }
  98 #endif
  99 }
 100
 101 /* Prints information on active (if 'active') and passive (if 'passive')
 102  * connection methods supported by the stream. */
 103 void
 104 stream_usage(const char *name, bool active, bool passive,
 105              bool bootstrap OVS_UNUSED)
 106 {
 107     /* Really this should be implemented via callbacks into the stream
 108      * providers, but that seems too heavy-weight to bother with at the
 109      * moment. */
 110
 111     printf("\n");
 112     if (active) {
 113         printf("Active %s connection methods:\n", name);
 114         printf("  tcp:IP:PORT             "
 115                "PORT at remote IP\n");
 116 #ifdef HAVE_OPENSSL
 117         printf("  ssl:IP:PORT             "
 118                "SSL PORT at remote IP\n");
 119 #endif
 120         printf("  unix:FILE               "
 121                "Unix domain socket named FILE\n");
 122     }
 123
 124     if (passive) {
 125         printf("Passive %s connection methods:\n", name);
 126         printf("  ptcp:PORT[:IP]          "
 127                "listen to TCP PORT on IP\n");
 128 #ifdef HAVE_OPENSSL
 129         printf("  pssl:PORT[:IP]          "
 130                "listen for SSL on PORT on IP\n");
 131 #endif
 132         printf("  punix:FILE              "
 133                "listen on Unix domain socket FILE\n");
 134     }
 135
 136 #ifdef HAVE_OPENSSL
 137     printf("PKI configuration (required to use SSL):\n"
 138            "  -p, --private-key=FILE  file with private key\n"
 139            "  -c, --certificate=FILE  file with certificate for private key\n"
 140            "  -C, --ca-cert=FILE      file with peer CA certificate\n");
 141     if (bootstrap) {
 142         printf("  --bootstrap-ca-cert=FILE  file with peer CA certificate "
 143                "to read or create\n");
 144     }
 145 #endif
 146 }
 147
 148 /* Given 'name', a stream name in the form "TYPE:ARGS", stores the class
 149  * named "TYPE" into '*classp' and returns 0.  Returns EAFNOSUPPORT and stores
 150  * a null pointer into '*classp' if 'name' is in the wrong form or if no such
 151  * class exists. */
 152 static int
 153 stream_lookup_class(const char *name, struct stream_class **classp)
 154 {
 155     size_t prefix_len;
 156     size_t i;
 157
 158     check_stream_classes();
 159
 160     *classp = NULL;
 161     prefix_len = strcspn(name, ":");
 162     if (name[prefix_len] == '\0') {
 163         return EAFNOSUPPORT;
 164     }
 165     for (i = 0; i < ARRAY_SIZE(stream_classes); i++) {
 166         struct stream_class *class = stream_classes[i];
 167         if (strlen(class->name) == prefix_len
 168             && !memcmp(class->name, name, prefix_len)) {
 169             *classp = class;
 170             return 0;
 171         }
 172     }
 173     return EAFNOSUPPORT;
 174 }
 175
 176 /* Returns 0 if 'name' is a stream name in the form "TYPE:ARGS" and TYPE is
 177  * a supported stream type, otherwise EAFNOSUPPORT.  */
 178 int
 179 stream_verify_name(const char *name)
 180 {
 181     struct stream_class *class;
 182     return stream_lookup_class(name, &class);
 183 }
 184
 185 /* Attempts to connect a stream to a remote peer.  'name' is a connection name
 186  * in the form "TYPE:ARGS", where TYPE is an active stream class's name and
 187  * ARGS are stream class-specific.
 188  *
 189  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 190  * stores a pointer to the new connection in '*streamp', otherwise a null
 191  * pointer.  */
 192 int
 193 stream_open(const char *name, struct stream **streamp)
 194 {
 195     struct stream_class *class;
 196     struct stream *stream;
 197     char *suffix_copy;
 198     int error;
 199
 200     COVERAGE_INC(stream_open);
 201
 202     /* Look up the class. */
 203     error = stream_lookup_class(name, &class);
 204     if (!class) {
 205         goto error;
 206     }
 207
 208     /* Call class's "open" function. */
 209     suffix_copy = xstrdup(strchr(name, ':') + 1);
 210     error = class->open(name, suffix_copy, &stream);
 211     free(suffix_copy);
 212     if (error) {
 213         goto error;
 214     }
 215
 216     /* Success. */
 217     *streamp = stream;
 218     return 0;
 219
 220 error:
 221     *streamp = NULL;
 222     return error;
 223 }
 224
 225 int
 226 stream_open_block(const char *name, struct stream **streamp)
 227 {
 228     struct stream *stream;
 229     int error;
 230
 231     error = stream_open(name, &stream);
 232     while (error == EAGAIN) {
 233         stream_run(stream);
 234         stream_run_wait(stream);
 235         stream_connect_wait(stream);
 236         poll_block();
 237         error = stream_connect(stream);
 238         assert(error != EINPROGRESS);
 239     }
 240     if (error) {
 241         stream_close(stream);
 242         *streamp = NULL;
 243     } else {
 244         *streamp = stream;
 245     }
 246     return error;
 247 }
 248
 249 /* Closes 'stream'. */
 250 void
 251 stream_close(struct stream *stream)
 252 {
 253     if (stream != NULL) {
 254         char *name = stream->name;
 255         (stream->class->close)(stream);
 256         free(name);
 257     }
 258 }
 259
 260 /* Returns the name of 'stream', that is, the string passed to
 261  * stream_open(). */
 262 const char *
 263 stream_get_name(const struct stream *stream)
 264 {
 265     return stream ? stream->name : "(null)";
 266 }
 267
 268 /* Returns the IP address of the peer, or 0 if the peer is not connected over
 269  * an IP-based protocol or if its IP address is not yet known. */
 270 uint32_t
 271 stream_get_remote_ip(const struct stream *stream)
 272 {
 273     return stream->remote_ip;
 274 }
 275
 276 /* Returns the transport port of the peer, or 0 if the connection does not
 277  * contain a port or if the port is not yet known. */
 278 uint16_t
 279 stream_get_remote_port(const struct stream *stream)
 280 {
 281     return stream->remote_port;
 282 }
 283
 284 /* Returns the IP address used to connect to the peer, or 0 if the connection
 285  * is not an IP-based protocol or if its IP address is not yet known. */
 286 uint32_t
 287 stream_get_local_ip(const struct stream *stream)
 288 {
 289     return stream->local_ip;
 290 }
 291
 292 /* Returns the transport port used to connect to the peer, or 0 if the
 293  * connection does not contain a port or if the port is not yet known. */
 294 uint16_t
 295 stream_get_local_port(const struct stream *stream)
 296 {
 297     return stream->local_port;
 298 }
 299
 300 static void
 301 scs_connecting(struct stream *stream)
 302 {
 303     int retval = (stream->class->connect)(stream);
 304     assert(retval != EINPROGRESS);
 305     if (!retval) {
 306         stream->state = SCS_CONNECTED;
 307     } else if (retval != EAGAIN) {
 308         stream->state = SCS_DISCONNECTED;
 309         stream->error = retval;
 310     }
 311 }
 312
 313 /* Tries to complete the connection on 'stream', which must be an active
 314  * stream.  If 'stream''s connection is complete, returns 0 if the connection
 315  * was successful or a positive errno value if it failed.  If the
 316  * connection is still in progress, returns EAGAIN. */
 317 int
 318 stream_connect(struct stream *stream)
 319 {
 320     enum stream_state last_state;
 321
 322     do {
 323         last_state = stream->state;
 324         switch (stream->state) {
 325         case SCS_CONNECTING:
 326             scs_connecting(stream);
 327             break;
 328
 329         case SCS_CONNECTED:
 330             return 0;
 331
 332         case SCS_DISCONNECTED:
 333             return stream->error;
 334
 335         default:
 336             NOT_REACHED();
 337         }
 338     } while (stream->state != last_state);
 339
 340     return EAGAIN;
 341 }
 342
 343 /* Tries to receive up to 'n' bytes from 'stream' into 'buffer', and returns:
 344  *
 345  *     - If successful, the number of bytes received (between 1 and 'n').
 346  *
 347  *     - On error, a negative errno value.
 348  *
 349  *     - 0, if the connection has been closed in the normal fashion, or if 'n'
 350  *       is zero.
 351  *
 352  * The recv function will not block waiting for a packet to arrive.  If no
 353  * data have been received, it returns -EAGAIN immediately. */
 354 int
 355 stream_recv(struct stream *stream, void *buffer, size_t n)
 356 {
 357     int retval = stream_connect(stream);
 358     return (retval ? -retval
 359             : n == 0 ? 0
 360             : (stream->class->recv)(stream, buffer, n));
 361 }
 362
 363 /* Tries to send up to 'n' bytes of 'buffer' on 'stream', and returns:
 364  *
 365  *     - If successful, the number of bytes sent (between 1 and 'n').  0 is
 366  *       only a valid return value if 'n' is 0.
 367  *
 368  *     - On error, a negative errno value.
 369  *
 370  * The send function will not block.  If no bytes can be immediately accepted
 371  * for transmission, it returns -EAGAIN immediately. */
 372 int
 373 stream_send(struct stream *stream, const void *buffer, size_t n)
 374 {
 375     int retval = stream_connect(stream);
 376     return (retval ? -retval
 377             : n == 0 ? 0
 378             : (stream->class->send)(stream, buffer, n));
 379 }
 380
 381 /* Allows 'stream' to perform maintenance activities, such as flushing
 382  * output buffers. */
 383 void
 384 stream_run(struct stream *stream)
 385 {
 386     if (stream->class->run) {
 387         (stream->class->run)(stream);
 388     }
 389 }
 390
 391 /* Arranges for the poll loop to wake up when 'stream' needs to perform
 392  * maintenance activities. */
 393 void
 394 stream_run_wait(struct stream *stream)
 395 {
 396     if (stream->class->run_wait) {
 397         (stream->class->run_wait)(stream);
 398     }
 399 }
 400
 401 /* Arranges for the poll loop to wake up when 'stream' is ready to take an
 402  * action of the given 'type'. */
 403 void
 404 stream_wait(struct stream *stream, enum stream_wait_type wait)
 405 {
 406     assert(wait == STREAM_CONNECT || wait == STREAM_RECV
 407            || wait == STREAM_SEND);
 408
 409     switch (stream->state) {
 410     case SCS_CONNECTING:
 411         wait = STREAM_CONNECT;
 412         break;
 413
 414     case SCS_DISCONNECTED:
 415         poll_immediate_wake();
 416         return;
 417     }
 418     (stream->class->wait)(stream, wait);
 419 }
 420
 421 void
 422 stream_connect_wait(struct stream *stream)
 423 {
 424     stream_wait(stream, STREAM_CONNECT);
 425 }
 426
 427 void
 428 stream_recv_wait(struct stream *stream)
 429 {
 430     stream_wait(stream, STREAM_RECV);
 431 }
 432
 433 void
 434 stream_send_wait(struct stream *stream)
 435 {
 436     stream_wait(stream, STREAM_SEND);
 437 }
 438
 439 /* Given 'name', a pstream name in the form "TYPE:ARGS", stores the class
 440  * named "TYPE" into '*classp' and returns 0.  Returns EAFNOSUPPORT and stores
 441  * a null pointer into '*classp' if 'name' is in the wrong form or if no such
 442  * class exists. */
 443 static int
 444 pstream_lookup_class(const char *name, struct pstream_class **classp)
 445 {
 446     size_t prefix_len;
 447     size_t i;
 448
 449     check_stream_classes();
 450
 451     *classp = NULL;
 452     prefix_len = strcspn(name, ":");
 453     if (name[prefix_len] == '\0') {
 454         return EAFNOSUPPORT;
 455     }
 456     for (i = 0; i < ARRAY_SIZE(pstream_classes); i++) {
 457         struct pstream_class *class = pstream_classes[i];
 458         if (strlen(class->name) == prefix_len
 459             && !memcmp(class->name, name, prefix_len)) {
 460             *classp = class;
 461             return 0;
 462         }
 463     }
 464     return EAFNOSUPPORT;
 465 }
 466
 467 /* Returns 0 if 'name' is a pstream name in the form "TYPE:ARGS" and TYPE is
 468  * a supported pstream type, otherwise EAFNOSUPPORT.  */
 469 int
 470 pstream_verify_name(const char *name)
 471 {
 472     struct pstream_class *class;
 473     return pstream_lookup_class(name, &class);
 474 }
 475
 476 /* Attempts to start listening for remote stream connections.  'name' is a
 477  * connection name in the form "TYPE:ARGS", where TYPE is an passive stream
 478  * class's name and ARGS are stream class-specific.
 479  *
 480  * Returns 0 if successful, otherwise a positive errno value.  If successful,
 481  * stores a pointer to the new connection in '*pstreamp', otherwise a null
 482  * pointer.  */
 483 int
 484 pstream_open(const char *name, struct pstream **pstreamp)
 485 {
 486     struct pstream_class *class;
 487     struct pstream *pstream;
 488     char *suffix_copy;
 489     int error;
 490
 491     COVERAGE_INC(pstream_open);
 492
 493     /* Look up the class. */
 494     error = pstream_lookup_class(name, &class);
 495     if (!class) {
 496         goto error;
 497     }
 498
 499     /* Call class's "open" function. */
 500     suffix_copy = xstrdup(strchr(name, ':') + 1);
 501     error = class->listen(name, suffix_copy, &pstream);
 502     free(suffix_copy);
 503     if (error) {
 504         goto error;
 505     }
 506
 507     /* Success. */
 508     *pstreamp = pstream;
 509     return 0;
 510
 511 error:
 512     *pstreamp = NULL;
 513     return error;
 514 }
 515
 516 /* Returns the name that was used to open 'pstream'.  The caller must not
 517  * modify or free the name. */
 518 const char *
 519 pstream_get_name(const struct pstream *pstream)
 520 {
 521     return pstream->name;
 522 }
 523
 524 /* Closes 'pstream'. */
 525 void
 526 pstream_close(struct pstream *pstream)
 527 {
 528     if (pstream != NULL) {
 529         char *name = pstream->name;
 530         (pstream->class->close)(pstream);
 531         free(name);
 532     }
 533 }
 534
 535 /* Tries to accept a new connection on 'pstream'.  If successful, stores the
 536  * new connection in '*new_stream' and returns 0.  Otherwise, returns a
 537  * positive errno value.
 538  *
 539  * pstream_accept() will not block waiting for a connection.  If no connection
 540  * is ready to be accepted, it returns EAGAIN immediately. */
 541 int
 542 pstream_accept(struct pstream *pstream, struct stream **new_stream)
 543 {
 544     int retval = (pstream->class->accept)(pstream, new_stream);
 545     if (retval) {
 546         *new_stream = NULL;
 547     } else {
 548         assert((*new_stream)->state != SCS_CONNECTING
 549                || (*new_stream)->class->connect);
 550     }
 551     return retval;
 552 }
 553
 554 /* Tries to accept a new connection on 'pstream'.  If successful, stores the
 555  * new connection in '*new_stream' and returns 0.  Otherwise, returns a
 556  * positive errno value.
 557  *
 558  * pstream_accept_block() blocks until a connection is ready or until an error
 559  * occurs.  It will not return EAGAIN. */
 560 int
 561 pstream_accept_block(struct pstream *pstream, struct stream **new_stream)
 562 {
 563     int error;
 564
 565     while ((error = pstream_accept(pstream, new_stream)) == EAGAIN) {
 566         pstream_wait(pstream);
 567         poll_block();
 568     }
 569     if (error) {
 570         *new_stream = NULL;
 571     }
 572     return error;
 573 }
 574
 575 void
 576 pstream_wait(struct pstream *pstream)
 577 {
 578     (pstream->class->wait)(pstream);
 579 }
 580 \f
 581 /* Initializes 'stream' as a new stream named 'name', implemented via 'class'.
 582  * The initial connection status, supplied as 'connect_status', is interpreted
 583  * as follows:
 584  *
 585  *      - 0: 'stream' is connected.  Its 'send' and 'recv' functions may be
 586  *        called in the normal fashion.
 587  *
 588  *      - EAGAIN: 'stream' is trying to complete a connection.  Its 'connect'
 589  *        function should be called to complete the connection.
 590  *
 591  *      - Other positive errno values indicate that the connection failed with
 592  *        the specified error.
 593  *
 594  * After calling this function, stream_close() must be used to destroy
 595  * 'stream', otherwise resources will be leaked.
 596  *
 597  * The caller retains ownership of 'name'. */
 598 void
 599 stream_init(struct stream *stream, struct stream_class *class,
 600             int connect_status, const char *name)
 601 {
 602     stream->class = class;
 603     stream->state = (connect_status == EAGAIN ? SCS_CONNECTING
 604                     : !connect_status ? SCS_CONNECTED
 605                     : SCS_DISCONNECTED);
 606     stream->error = connect_status;
 607     stream->name = xstrdup(name);
 608     assert(stream->state != SCS_CONNECTING || class->connect);
 609 }
 610
 611 void
 612 stream_set_remote_ip(struct stream *stream, uint32_t ip)
 613 {
 614     stream->remote_ip = ip;
 615 }
 616
 617 void
 618 stream_set_remote_port(struct stream *stream, uint16_t port)
 619 {
 620     stream->remote_port = port;
 621 }
 622
 623 void
 624 stream_set_local_ip(struct stream *stream, uint32_t ip)
 625 {
 626     stream->local_ip = ip;
 627 }
 628
 629 void
 630 stream_set_local_port(struct stream *stream, uint16_t port)
 631 {
 632     stream->local_port = port;
 633 }
 634
 635 void
 636 pstream_init(struct pstream *pstream, struct pstream_class *class,
 637             const char *name)
 638 {
 639     pstream->class = class;
 640     pstream->name = xstrdup(name);
 641 }