text: /*
   * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at:
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include <config.h>
  #include "stream-provider.h"
  #include <errno.h>
  #include <inttypes.h>
  #include <netinet/in.h>
  #include <poll.h>
  #include <stdlib.h>
  #include <string.h>
  #include "coverage.h"
  #include "dynamic-string.h"
  #include "fatal-signal.h"
  #include "flow.h"
  #include "jsonrpc.h"
  #include "ofp-print.h"
  #include "ofpbuf.h"
  #include "openflow/nicira-ext.h"
  #include "openflow/openflow.h"
  #include "packets.h"
  #include "poll-loop.h"
  #include "random.h"
  #include "util.h"
  #include "vlog.h"
  
  VLOG_DEFINE_THIS_MODULE(stream);
  
  COVERAGE_DEFINE(pstream_open);
  COVERAGE_DEFINE(stream_open);
  
  /* State of an active stream.*/
  enum stream_state {
      SCS_CONNECTING,             /* Underlying stream is not connected. */
      SCS_CONNECTED,              /* Connection established. */
      SCS_DISCONNECTED            /* Connection failed or connection closed. */
  };
  
  static const struct stream_class *stream_classes[] = {
      &tcp_stream_class,
      &unix_stream_class,
  #ifdef HAVE_OPENSSL
      &ssl_stream_class,
  #endif
  };
  
  static const struct pstream_class *pstream_classes[] = {
      &ptcp_pstream_class,
      &punix_pstream_class,
  #ifdef HAVE_OPENSSL
      &pssl_pstream_class,
  #endif
  };
  
  /* Check the validity of the stream class structures. */
  static void
  check_stream_classes(void)
  {
  #ifndef NDEBUG
      size_t i;
  
      for (i = 0; i < ARRAY_SIZE(stream_classes); i++) {
          const struct stream_class *class = stream_classes[i];
          ovs_assert(class->name != NULL);
          ovs_assert(class->open != NULL);
          if (class->close || class->recv || class->send || class->run
              || class->run_wait || class->wait) {
              ovs_assert(class->close != NULL);
              ovs_assert(class->recv != NULL);
              ovs_assert(class->send != NULL);
              ovs_assert(class->wait != NULL);
          } else {
              /* This class delegates to another one. */
          }
      }
  
      for (i = 0; i < ARRAY_SIZE(pstream_classes); i++) {
          const struct pstream_class *class = pstream_classes[i];
          ovs_assert(class->name != NULL);
          ovs_assert(class->listen != NULL);
          if (class->close || class->accept || class->wait) {
              ovs_assert(class->close != NULL);
              ovs_assert(class->accept != NULL);
              ovs_assert(class->wait != NULL);
          } else {
              /* This class delegates to another one. */
          }
      }
  #endif
  }
  
  /* Prints information on active (if 'active') and passive (if 'passive')
   * connection methods supported by the stream. */
  void
  stream_usage(const char *name, bool active, bool passive,
               bool bootstrap OVS_UNUSED)
  {
      /* Really this should be implemented via callbacks into the stream
       * providers, but that seems too heavy-weight to bother with at the
       * moment. */
  
      printf("\n");
      if (active) {
          printf("Active %s connection methods:\n", name);
          printf("  tcp:IP:PORT             "
                 "PORT at remote IP\n");
  #ifdef HAVE_OPENSSL
          printf("  ssl:IP:PORT             "
                 "SSL PORT at remote IP\n");
  #endif
          printf("  unix:FILE               "
                 "Unix domain socket named FILE\n");
      }
  
      if (passive) {
          printf("Passive %s connection methods:\n", name);
          printf("  ptcp:PORT[:IP]          "
                 "listen to TCP PORT on IP\n");
  #ifdef HAVE_OPENSSL
          printf("  pssl:PORT[:IP]          "
                 "listen for SSL on PORT on IP\n");
  #endif
          printf("  punix:FILE              "
                 "listen on Unix domain socket FILE\n");
      }
  
  #ifdef HAVE_OPENSSL
      printf("PKI configuration (required to use SSL):\n"
             "  -p, --private-key=FILE  file with private key\n"
             "  -c, --certificate=FILE  file with certificate for private key\n"
             "  -C, --ca-cert=FILE      file with peer CA certificate\n");
      if (bootstrap) {
          printf("  --bootstrap-ca-cert=FILE  file with peer CA certificate "
                 "to read or create\n");
      }
  #endif
  }
  
  /* Given 'name', a stream name in the form "TYPE:ARGS", stores the class
   * named "TYPE" into '*classp' and returns 0.  Returns EAFNOSUPPORT and stores
   * a null pointer into '*classp' if 'name' is in the wrong form or if no such
   * class exists. */
  static int
  stream_lookup_class(const char *name, const struct stream_class **classp)
  {
      size_t prefix_len;
      size_t i;
  
      check_stream_classes();
  
      *classp = NULL;
      prefix_len = strcspn(name, ":");
      if (name[prefix_len] == '\0') {
          return EAFNOSUPPORT;
      }
      for (i = 0; i < ARRAY_SIZE(stream_classes); i++) {
          const struct stream_class *class = stream_classes[i];
          if (strlen(class->name) == prefix_len
              && !memcmp(class->name, name, prefix_len)) {
              *classp = class;
              return 0;
          }
      }
      return EAFNOSUPPORT;
  }
  
  /* Returns 0 if 'name' is a stream name in the form "TYPE:ARGS" and TYPE is
   * a supported stream type, otherwise EAFNOSUPPORT.  */
  int
  stream_verify_name(const char *name)
  {
      const struct stream_class *class;
      return stream_lookup_class(name, &class);
  }
  
  /* Attempts to connect a stream to a remote peer.  'name' is a connection name
   * in the form "TYPE:ARGS", where TYPE is an active stream class's name and
   * ARGS are stream class-specific.
   *
   * Returns 0 if successful, otherwise a positive errno value.  If successful,
   * stores a pointer to the new connection in '*streamp', otherwise a null
   * pointer.  */
  int
  stream_open(const char *name, struct stream **streamp, uint8_t dscp)
  {
      const struct stream_class *class;
      struct stream *stream;
      char *suffix_copy;
      int error;
  
      COVERAGE_INC(stream_open);
  
      /* Look up the class. */
      error = stream_lookup_class(name, &class);
      if (!class) {
          goto error;
      }
  
      /* Call class's "open" function. */
      suffix_copy = xstrdup(strchr(name, ':') + 1);
      error = class->open(name, suffix_copy, &stream, dscp);
      free(suffix_copy);
      if (error) {
          goto error;
      }
  
      /* Success. */
      *streamp = stream;
      return 0;
  
  error:
      *streamp = NULL;
      return error;
  }
  
  /* Blocks until a previously started stream connection attempt succeeds or
   * fails.  'error' should be the value returned by stream_open() and 'streamp'
   * should point to the stream pointer set by stream_open().  Returns 0 if
   * successful, otherwise a positive errno value other than EAGAIN or
   * EINPROGRESS.  If successful, leaves '*streamp' untouched; on error, closes
   * '*streamp' and sets '*streamp' to null.
   *
   * Typical usage:
   *   error = stream_open_block(stream_open("tcp:1.2.3.4:5", &stream), &stream);
   */
  int
  stream_open_block(int error, struct stream **streamp)
  {
      struct stream *stream = *streamp;
  
      fatal_signal_run();
  
      if (!error) {
          while ((error = stream_connect(stream)) == EAGAIN) {
              stream_run(stream);
              stream_run_wait(stream);
              stream_connect_wait(stream);
              poll_block();
          }
          ovs_assert(error != EINPROGRESS);
      }
  
      if (error) {
          stream_close(stream);
          *streamp = NULL;
      } else {
          *streamp = stream;
      }
      return error;
  }
  
  /* Closes 'stream'. */
  void
  stream_close(struct stream *stream)
  {
      if (stream != NULL) {
          char *name = stream->name;
          (stream->class->close)(stream);
          free(name);
      }
  }
  
  /* Returns the name of 'stream', that is, the string passed to
   * stream_open(). */
  const char *
  stream_get_name(const struct stream *stream)
  {
      return stream ? stream->name : "(null)";
  }
  
  static void
  scs_connecting(struct stream *stream)
  {
      int retval = (stream->class->connect)(stream);
      ovs_assert(retval != EINPROGRESS);
      if (!retval) {
          stream->state = SCS_CONNECTED;
      } else if (retval != EAGAIN) {
          stream->state = SCS_DISCONNECTED;
          stream->error = retval;
      }
  }
  
  /* Tries to complete the connection on 'stream'.  If 'stream''s connection is
   * complete, returns 0 if the connection was successful or a positive errno
   * value if it failed.  If the connection is still in progress, returns
   * EAGAIN. */
  int
  stream_connect(struct stream *stream)
  {
      enum stream_state last_state;
  
      do {
          last_state = stream->state;
          switch (stream->state) {
          case SCS_CONNECTING:
              scs_connecting(stream);
              break;
  
          case SCS_CONNECTED:
              return 0;
  
          case SCS_DISCONNECTED:
              return stream->error;
  
          default:
              OVS_NOT_REACHED();
          }
      } while (stream->state != last_state);
  
      return EAGAIN;
  }
  
  /* Tries to receive up to 'n' bytes from 'stream' into 'buffer', and returns:
   *
   *     - If successful, the number of bytes received (between 1 and 'n').
   *
   *     - On error, a negative errno value.
   *
   *     - 0, if the connection has been closed in the normal fashion, or if 'n'
   *       is zero.
   *
   * The recv function will not block waiting for a packet to arrive.  If no
   * data have been received, it returns -EAGAIN immediately. */
  int
  stream_recv(struct stream *stream, void *buffer, size_t n)
  {
      int retval = stream_connect(stream);
      return (retval ? -retval
              : n == 0 ? 0
              : (stream->class->recv)(stream, buffer, n));
  }
  
  /* Tries to send up to 'n' bytes of 'buffer' on 'stream', and returns:
   *
   *     - If successful, the number of bytes sent (between 1 and 'n').  0 is
   *       only a valid return value if 'n' is 0.
   *
   *     - On error, a negative errno value.
   *
   * The send function will not block.  If no bytes can be immediately accepted
   * for transmission, it returns -EAGAIN immediately. */
  int
  stream_send(struct stream *stream, const void *buffer, size_t n)
  {
      int retval = stream_connect(stream);
      return (retval ? -retval
              : n == 0 ? 0
              : (stream->class->send)(stream, buffer, n));
  }
  
  /* Allows 'stream' to perform maintenance activities, such as flushing
   * output buffers. */
  void
  stream_run(struct stream *stream)
  {
      if (stream->class->run) {
          (stream->class->run)(stream);
      }
  }
  
  /* Arranges for the poll loop to wake up when 'stream' needs to perform
   * maintenance activities. */
  void
  stream_run_wait(struct stream *stream)
  {
      if (stream->class->run_wait) {
          (stream->class->run_wait)(stream);
      }
  }
  
  /* Arranges for the poll loop to wake up when 'stream' is ready to take an
   * action of the given 'type'. */
  void
  stream_wait(struct stream *stream, enum stream_wait_type wait)
  {
      ovs_assert(wait == STREAM_CONNECT || wait == STREAM_RECV
                 || wait == STREAM_SEND);
  
      switch (stream->state) {
      case SCS_CONNECTING:
          wait = STREAM_CONNECT;
          break;
  
      case SCS_DISCONNECTED:
          poll_immediate_wake();
          return;
      }
      (stream->class->wait)(stream, wait);
  }
  
  void
  stream_connect_wait(struct stream *stream)
  {
      stream_wait(stream, STREAM_CONNECT);
  }
  
  void
  stream_recv_wait(struct stream *stream)
  {
      stream_wait(stream, STREAM_RECV);
  }
  
  void
  stream_send_wait(struct stream *stream)
  {
      stream_wait(stream, STREAM_SEND);
  }
  
  /* Given 'name', a pstream name in the form "TYPE:ARGS", stores the class
   * named "TYPE" into '*classp' and returns 0.  Returns EAFNOSUPPORT and stores
   * a null pointer into '*classp' if 'name' is in the wrong form or if no such
   * class exists. */
  static int
  pstream_lookup_class(const char *name, const struct pstream_class **classp)
  {
      size_t prefix_len;
      size_t i;
  
      check_stream_classes();
  
      *classp = NULL;
      prefix_len = strcspn(name, ":");
      if (name[prefix_len] == '\0') {
          return EAFNOSUPPORT;
      }
      for (i = 0; i < ARRAY_SIZE(pstream_classes); i++) {
          const struct pstream_class *class = pstream_classes[i];
          if (strlen(class->name) == prefix_len
              && !memcmp(class->name, name, prefix_len)) {
              *classp = class;
              return 0;
          }
      }
      return EAFNOSUPPORT;
  }
  
  /* Returns 0 if 'name' is a pstream name in the form "TYPE:ARGS" and TYPE is
   * a supported pstream type, otherwise EAFNOSUPPORT.  */
  int
  pstream_verify_name(const char *name)
  {
      const struct pstream_class *class;
      return pstream_lookup_class(name, &class);
  }
  
  /* Returns 1 if the stream or pstream specified by 'name' needs periodic probes
   * to verify connectivity.  For [p]streams which need probes, it can take a
   * long time to notice the connection has been dropped.  Returns 0 if the
   * stream or pstream does not need probes, and -1 if 'name' is not valid. */
  int
  stream_or_pstream_needs_probes(const char *name)
  {
      const struct pstream_class *pclass;
      const struct stream_class *class;
  
      if (!stream_lookup_class(name, &class)) {
          return class->needs_probes;
      } else if (!pstream_lookup_class(name, &pclass)) {
          return pclass->needs_probes;
      } else {
          return -1;
      }
  }
  
  /* Attempts to start listening for remote stream connections.  'name' is a
   * connection name in the form "TYPE:ARGS", where TYPE is an passive stream
   * class's name and ARGS are stream class-specific.
   *
   * Returns 0 if successful, otherwise a positive errno value.  If successful,
   * stores a pointer to the new connection in '*pstreamp', otherwise a null
   * pointer.  */
  int
  pstream_open(const char *name, struct pstream **pstreamp, uint8_t dscp)
  {
      const struct pstream_class *class;
      struct pstream *pstream;
      char *suffix_copy;
      int error;
  
      COVERAGE_INC(pstream_open);
  
      /* Look up the class. */
      error = pstream_lookup_class(name, &class);
      if (!class) {
          goto error;
      }
  
      /* Call class's "open" function. */
      suffix_copy = xstrdup(strchr(name, ':') + 1);
      error = class->listen(name, suffix_copy, &pstream, dscp);
      free(suffix_copy);
      if (error) {
          goto error;
      }
  
      /* Success. */
      *pstreamp = pstream;
      return 0;
  
  error:
      *pstreamp = NULL;
      return error;
  }
  
  /* Returns the name that was used to open 'pstream'.  The caller must not
   * modify or free the name. */
  const char *
  pstream_get_name(const struct pstream *pstream)
  {
      return pstream->name;
  }
  
  /* Closes 'pstream'. */
  void
  pstream_close(struct pstream *pstream)
  {
      if (pstream != NULL) {
          char *name = pstream->name;
          (pstream->class->close)(pstream);
          free(name);
      }
  }
  
  /* Tries to accept a new connection on 'pstream'.  If successful, stores the
   * new connection in '*new_stream' and returns 0.  Otherwise, returns a
   * positive errno value.
   *
   * pstream_accept() will not block waiting for a connection.  If no connection
   * is ready to be accepted, it returns EAGAIN immediately. */
  int
  pstream_accept(struct pstream *pstream, struct stream **new_stream)
  {
      int retval = (pstream->class->accept)(pstream, new_stream);
      if (retval) {
          *new_stream = NULL;
      } else {
          ovs_assert((*new_stream)->state != SCS_CONNECTING
                     || (*new_stream)->class->connect);
      }
      return retval;
  }
  
  /* Tries to accept a new connection on 'pstream'.  If successful, stores the
   * new connection in '*new_stream' and returns 0.  Otherwise, returns a
   * positive errno value.
   *
   * pstream_accept_block() blocks until a connection is ready or until an error
   * occurs.  It will not return EAGAIN. */
  int
  pstream_accept_block(struct pstream *pstream, struct stream **new_stream)
  {
      int error;
  
      fatal_signal_run();
      while ((error = pstream_accept(pstream, new_stream)) == EAGAIN) {
          pstream_wait(pstream);
          poll_block();
      }
      if (error) {
          *new_stream = NULL;
      }
      return error;
  }
  
  void
  pstream_wait(struct pstream *pstream)
  {
      (pstream->class->wait)(pstream);
  }
  
  int
  pstream_set_dscp(struct pstream *pstream, uint8_t dscp)
  {
      if (pstream->class->set_dscp) {
          return pstream->class->set_dscp(pstream, dscp);
      }
      return 0;
  }
  
  /* Returns the transport port on which 'pstream' is listening, or 0 if the
   * concept doesn't apply. */
  ovs_be16
  pstream_get_bound_port(const struct pstream *pstream)
  {
      return pstream->bound_port;
  }
  
  /* Initializes 'stream' as a new stream named 'name', implemented via 'class'.
   * The initial connection status, supplied as 'connect_status', is interpreted
   * as follows:
   *
   *      - 0: 'stream' is connected.  Its 'send' and 'recv' functions may be
   *        called in the normal fashion.
   *
   *      - EAGAIN: 'stream' is trying to complete a connection.  Its 'connect'
   *        function should be called to complete the connection.
   *
   *      - Other positive errno values indicate that the connection failed with
   *        the specified error.
   *
   * After calling this function, stream_close() must be used to destroy
   * 'stream', otherwise resources will be leaked.
   *
   * The caller retains ownership of 'name'. */
  void
  stream_init(struct stream *stream, const struct stream_class *class,
              int connect_status, const char *name)
  {
      memset(stream, 0, sizeof *stream);
      stream->class = class;
      stream->state = (connect_status == EAGAIN ? SCS_CONNECTING
                      : !connect_status ? SCS_CONNECTED
                      : SCS_DISCONNECTED);
      stream->error = connect_status;
      stream->name = xstrdup(name);
      ovs_assert(stream->state != SCS_CONNECTING || class->connect);
  }
  
  void
  pstream_init(struct pstream *pstream, const struct pstream_class *class,
              const char *name)
  {
      memset(pstream, 0, sizeof *pstream);
      pstream->class = class;
      pstream->name = xstrdup(name);
  }
  
  void
  pstream_set_bound_port(struct pstream *pstream, ovs_be16 port)
  {
      pstream->bound_port = port;
  }
  
  static int
  count_fields(const char *s_)
  {
      char *s, *field, *save_ptr;
      int n = 0;
  
      save_ptr = NULL;
      s = xstrdup(s_);
      for (field = strtok_r(s, ":", &save_ptr); field != NULL;
           field = strtok_r(NULL, ":", &save_ptr)) {
          n++;
      }
      free(s);
  
      return n;
  }
  
  /* Like stream_open(), but the port defaults to 'default_port' if no port
   * number is given. */
  int
  stream_open_with_default_port(const char *name_,
                                uint16_t default_port,
                                struct stream **streamp,
                                uint8_t dscp)
  {
      char *name;
      int error;
  
      if ((!strncmp(name_, "tcp:", 4) || !strncmp(name_, "ssl:", 4))
          && count_fields(name_) < 3) {
          if (default_port == OFP_OLD_PORT) {
              VLOG_WARN_ONCE("The default OpenFlow port number will change "
                             "from %d to %d in a future release",
                             OFP_OLD_PORT, OFP_PORT);
          } else if (default_port == OVSDB_OLD_PORT) {
              VLOG_WARN_ONCE("The default OVSDB port number will change "
                             "from %d to %d in a future release",
                             OVSDB_OLD_PORT, OVSDB_PORT);
          }
          name = xasprintf("%s:%d", name_, default_port);
      } else {
          name = xstrdup(name_);
      }
      error = stream_open(name, streamp, dscp);
      free(name);
  
      return error;
  }
  
  /* Like pstream_open(), but port defaults to 'default_port' if no port
   * number is given. */
  int
  pstream_open_with_default_port(const char *name_,
                                 uint16_t default_port,
                                 struct pstream **pstreamp,
                                 uint8_t dscp)
  {
      char *name;
      int error;
  
      if ((!strncmp(name_, "ptcp:", 5) || !strncmp(name_, "pssl:", 5))
          && count_fields(name_) < 2) {
          name = xasprintf("%s%d", name_, default_port);
      } else {
          name = xstrdup(name_);
      }
      error = pstream_open(name, pstreamp, dscp);
      free(name);
  
      return error;
  }
  
  /*
   * This function extracts IP address and port from the target string.
   *
   *     - On success, function returns true and fills *sin structure with port
   *       and IP address. If port was absent in target string then it will use
   *       corresponding default port value.
   *     - On error, function returns false and *sin contains garbage.
   */
  bool
  stream_parse_target_with_default_port(const char *target,
                                        uint16_t default_port,
                                        struct sockaddr_in *sin)
  {
      return ((!strncmp(target, "tcp:", 4) || !strncmp(target, "ssl:", 4))
               && inet_parse_active(target + 4, default_port, sin));
  }
  
  /* Attempts to guess the content type of a stream whose first few bytes were
   * the 'size' bytes of 'data'. */
  static enum stream_content_type
  stream_guess_content(const uint8_t *data, ssize_t size)
  {
      if (size >= 2) {
  #define PAIR(A, B) (((A) << 8) | (B))
          switch (PAIR(data[0], data[1])) {
          case PAIR(0x16, 0x03):  /* Handshake, version 3. */
              return STREAM_SSL;
          case PAIR('{', '"'):
              return STREAM_JSONRPC;
          case PAIR(OFP10_VERSION, 0 /* OFPT_HELLO */):
              return STREAM_OPENFLOW;
          }
      }
  
      return STREAM_UNKNOWN;
  }
  
  /* Returns a string represenation of 'type'. */
  static const char *
  stream_content_type_to_string(enum stream_content_type type)
  {
      switch (type) {
      case STREAM_UNKNOWN:
      default:
          return "unknown";
  
      case STREAM_JSONRPC:
          return "JSON-RPC";
  
      case STREAM_OPENFLOW:
          return "OpenFlow";
  
      case STREAM_SSL:
          return "SSL";
      }
  }
  
  /* Attempts to guess the content type of a stream whose first few bytes were
   * the 'size' bytes of 'data'.  If this is done successfully, and the guessed
   * content type is other than 'expected_type', then log a message in vlog
   * module 'module', naming 'stream_name' as the source, explaining what
   * content was expected and what was actually received. */
  void
  stream_report_content(const void *data, ssize_t size,
                        enum stream_content_type expected_type,
                        struct vlog_module *module, const char *stream_name)
  {
      static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
      enum stream_content_type actual_type;
  
      actual_type = stream_guess_content(data, size);
      if (actual_type != expected_type && actual_type != STREAM_UNKNOWN) {
          vlog_rate_limit(module, VLL_WARN, &rl,
                          "%s: received %s data on %s channel",
                          stream_name,
                          stream_content_type_to_string(actual_type),
                          stream_content_type_to_string(expected_type));
      }
  }
  