lib/stream-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2012, 2013, 2015 Nicira, Inc.
   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 #ifndef STREAM_PROVIDER_H
  18 #define STREAM_PROVIDER_H 1
  19
  20 #include <sys/types.h>
  21 #include "stream.h"
  22
  23 /* Active stream connection. */
  24
  25 /* Active stream connection.
  26  *
  27  * This structure should be treated as opaque by implementation. */
  28 struct stream {
  29     const struct stream_class *class;
  30     int state;
  31     int error;
  32     char *name;
  33 };
  34
  35 void stream_init(struct stream *, const struct stream_class *,
  36                  int connect_status, const char *name);
  37 static inline void stream_assert_class(const struct stream *stream,
  38                                        const struct stream_class *class)
  39 {
  40     ovs_assert(stream->class == class);
  41 }
  42
  43 struct stream_class {
  44     /* Prefix for connection names, e.g. "tcp", "ssl", "unix". */
  45     const char *name;
  46
  47     /* True if this stream needs periodic probes to verify connectivity.  For
  48      * streams which need probes, it can take a long time to notice the
  49      * connection was dropped. */
  50     bool needs_probes;
  51
  52     /* Attempts to connect to a peer.  'name' is the full connection name
  53      * provided by the user, e.g. "tcp:1.2.3.4".  This name is useful for error
  54      * messages but must not be modified.
  55      *
  56      * 'suffix' is a copy of 'name' following the colon and may be modified.
  57      * 'dscp' is the DSCP value that the new connection should use in the IP
  58      * packets it sends.
  59      *
  60      * Returns 0 if successful, otherwise a positive errno value.  If
  61      * successful, stores a pointer to the new connection in '*streamp'.
  62      *
  63      * The open function must not block waiting for a connection to complete.
  64      * If the connection cannot be completed immediately, it should return
  65      * EAGAIN (not EINPROGRESS, as returned by the connect system call) and
  66      * continue the connection in the background. */
  67     int (*open)(const char *name, char *suffix, struct stream **streamp,
  68                 uint8_t dscp);
  69
  70     /* Closes 'stream' and frees associated memory. */
  71     void (*close)(struct stream *stream);
  72
  73     /* Tries to complete the connection on 'stream'.  If 'stream''s connection
  74      * is complete, returns 0 if the connection was successful or a positive
  75      * errno value if it failed.  If the connection is still in progress,
  76      * returns EAGAIN.
  77      *
  78      * The connect function must not block waiting for the connection to
  79      * complete; instead, it should return EAGAIN immediately. */
  80     int (*connect)(struct stream *stream);
  81
  82     /* Tries to receive up to 'n' bytes from 'stream' into 'buffer', and
  83      * returns:
  84      *
  85      *     - If successful, the number of bytes received (between 1 and 'n').
  86      *
  87      *     - On error, a negative errno value.
  88      *
  89      *     - 0, if the connection has been closed in the normal fashion.
  90      *
  91      * The recv function will not be passed a zero 'n'.
  92      *
  93      * The recv function must not block waiting for data to arrive.  If no data
  94      * have been received, it should return -EAGAIN immediately. */
  95     ssize_t (*recv)(struct stream *stream, void *buffer, size_t n);
  96
  97     /* Tries to send up to 'n' bytes of 'buffer' on 'stream', and returns:
  98      *
  99      *     - If successful, the number of bytes sent (between 1 and 'n').
 100      *
 101      *     - On error, a negative errno value.
 102      *
 103      *     - Never returns 0.
 104      *
 105      * The send function will not be passed a zero 'n'.
 106      *
 107      * The send function must not block.  If no bytes can be immediately
 108      * accepted for transmission, it should return -EAGAIN immediately. */
 109     ssize_t (*send)(struct stream *stream, const void *buffer, size_t n);
 110
 111     /* Allows 'stream' to perform maintenance activities, such as flushing
 112      * output buffers.
 113      *
 114      * May be null if 'stream' doesn't have anything to do here. */
 115     void (*run)(struct stream *stream);
 116
 117     /* Arranges for the poll loop to wake up when 'stream' needs to perform
 118      * maintenance activities.
 119      *
 120      * May be null if 'stream' doesn't have anything to do here. */
 121     void (*run_wait)(struct stream *stream);
 122
 123     /* Arranges for the poll loop to wake up when 'stream' is ready to take an
 124      * action of the given 'type'. */
 125     void (*wait)(struct stream *stream, enum stream_wait_type type);
 126 };
 127 \f
 128 /* Passive listener for incoming stream connections.
 129  *
 130  * This structure should be treated as opaque by stream implementations. */
 131 struct pstream {
 132     const struct pstream_class *class;
 133     char *name;
 134     ovs_be16 bound_port;
 135 };
 136
 137 void pstream_init(struct pstream *, const struct pstream_class *, const char *name);
 138 void pstream_set_bound_port(struct pstream *, ovs_be16 bound_port);
 139 static inline void pstream_assert_class(const struct pstream *pstream,
 140                                         const struct pstream_class *class)
 141 {
 142     ovs_assert(pstream->class == class);
 143 }
 144
 145 struct pstream_class {
 146     /* Prefix for connection names, e.g. "ptcp", "pssl", "punix". */
 147     const char *name;
 148
 149     /* True if this pstream needs periodic probes to verify connectivity.  For
 150      * pstreams which need probes, it can take a long time to notice the
 151      * connection was dropped. */
 152     bool needs_probes;
 153
 154     /* Attempts to start listening for stream connections.  'name' is the full
 155      * connection name provided by the user, e.g. "ptcp:1234".  This name is
 156      * useful for error messages but must not be modified.
 157      *
 158      * 'suffix' is a copy of 'name' following the colon and may be modified.
 159      * 'dscp' is the DSCP value that the new connection should use in the IP
 160      * packets it sends.
 161      *
 162      * Returns 0 if successful, otherwise a positive errno value.  If
 163      * successful, stores a pointer to the new connection in '*pstreamp'.
 164      *
 165      * The listen function must not block.  If the connection cannot be
 166      * completed immediately, it should return EAGAIN (not EINPROGRESS, as
 167      * returned by the connect system call) and continue the connection in the
 168      * background. */
 169     int (*listen)(const char *name, char *suffix, struct pstream **pstreamp,
 170                   uint8_t dscp);
 171
 172     /* Closes 'pstream' and frees associated memory. */
 173     void (*close)(struct pstream *pstream);
 174
 175     /* Tries to accept a new connection on 'pstream'.  If successful, stores
 176      * the new connection in '*new_streamp' and returns 0.  Otherwise, returns
 177      * a positive errno value.
 178      *
 179      * The accept function must not block waiting for a connection.  If no
 180      * connection is ready to be accepted, it should return EAGAIN. */
 181     int (*accept)(struct pstream *pstream, struct stream **new_streamp);
 182
 183     /* Arranges for the poll loop to wake up when a connection is ready to be
 184      * accepted on 'pstream'. */
 185     void (*wait)(struct pstream *pstream);
 186 };
 187
 188 /* Active and passive stream classes. */
 189 extern const struct stream_class tcp_stream_class;
 190 extern const struct pstream_class ptcp_pstream_class;
 191 #ifndef _WIN32
 192 extern const struct stream_class unix_stream_class;
 193 extern const struct pstream_class punix_pstream_class;
 194 #else
 195 extern const struct stream_class windows_stream_class;
 196 extern const struct pstream_class pwindows_pstream_class;
 197 #endif
 198 #ifdef HAVE_OPENSSL
 199 extern const struct stream_class ssl_stream_class;
 200 extern const struct pstream_class pssl_pstream_class;
 201 #endif
 202
 203 #endif /* stream-provider.h */