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