lib/stream-provider.h

   1 /*
   2  * Copyright (c) 2009, 2010, 2012, 2013 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     ovs_be32 remote_ip;
  33     ovs_be16 remote_port;
  34     ovs_be32 local_ip;
  35     ovs_be16 local_port;
  36     char *name;
  37 };
  38
  39 void stream_init(struct stream *, const struct stream_class *,
  40                  int connect_status, const char *name);
  41 void stream_set_remote_ip(struct stream *, ovs_be32 remote_ip);
  42 void stream_set_remote_port(struct stream *, ovs_be16 remote_port);
  43 void stream_set_local_ip(struct stream *, ovs_be32 local_ip);
  44 void stream_set_local_port(struct stream *, ovs_be16 local_port);
  45 static inline void stream_assert_class(const struct stream *stream,
  46                                        const struct stream_class *class)
  47 {
  48     ovs_assert(stream->class == class);
  49 }
  50
  51 struct stream_class {
  52     /* Prefix for connection names, e.g. "tcp", "ssl", "unix". */
  53     const char *name;
  54
  55     /* True if this stream needs periodic probes to verify connectivity.  For
  56      * streams which need probes, it can take a long time to notice the
  57      * connection was dropped. */
  58     bool needs_probes;
  59
  60     /* Attempts to connect to a peer.  'name' is the full connection name
  61      * provided by the user, e.g. "tcp:1.2.3.4".  This name is useful for error
  62      * messages but must not be modified.
  63      *
  64      * 'suffix' is a copy of 'name' following the colon and may be modified.
  65      * 'dscp' is the DSCP value that the new connection should use in the IP
  66      * packets it sends.
  67      *
  68      * Returns 0 if successful, otherwise a positive errno value.  If
  69      * successful, stores a pointer to the new connection in '*streamp'.
  70      *
  71      * The open function must not block waiting for a connection to complete.
  72      * If the connection cannot be completed immediately, it should return
  73      * EAGAIN (not EINPROGRESS, as returned by the connect system call) and
  74      * continue the connection in the background. */
  75     int (*open)(const char *name, char *suffix, struct stream **streamp,
  76                 uint8_t dscp);
  77
  78     /* Closes 'stream' and frees associated memory. */
  79     void (*close)(struct stream *stream);
  80
  81     /* Tries to complete the connection on 'stream'.  If 'stream''s connection
  82      * is complete, returns 0 if the connection was successful or a positive
  83      * errno value if it failed.  If the connection is still in progress,
  84      * returns EAGAIN.
  85      *
  86      * The connect function must not block waiting for the connection to
  87      * complete; instead, it should return EAGAIN immediately. */
  88     int (*connect)(struct stream *stream);
  89
  90     /* Tries to receive up to 'n' bytes from 'stream' into 'buffer', and
  91      * returns:
  92      *
  93      *     - If successful, the number of bytes received (between 1 and 'n').
  94      *
  95      *     - On error, a negative errno value.
  96      *
  97      *     - 0, if the connection has been closed in the normal fashion.
  98      *
  99      * The recv function will not be passed a zero 'n'.
 100      *
 101      * The recv function must not block waiting for data to arrive.  If no data
 102      * have been received, it should return -EAGAIN immediately. */
 103     ssize_t (*recv)(struct stream *stream, void *buffer, size_t n);
 104
 105     /* Tries to send up to 'n' bytes of 'buffer' on 'stream', and returns:
 106      *
 107      *     - If successful, the number of bytes sent (between 1 and 'n').
 108      *
 109      *     - On error, a negative errno value.
 110      *
 111      *     - Never returns 0.
 112      *
 113      * The send function will not be passed a zero 'n'.
 114      *
 115      * The send function must not block.  If no bytes can be immediately
 116      * accepted for transmission, it should return -EAGAIN immediately. */
 117     ssize_t (*send)(struct stream *stream, const void *buffer, size_t n);
 118
 119     /* Allows 'stream' to perform maintenance activities, such as flushing
 120      * output buffers.
 121      *
 122      * May be null if 'stream' doesn't have anything to do here. */
 123     void (*run)(struct stream *stream);
 124
 125     /* Arranges for the poll loop to wake up when 'stream' needs to perform
 126      * maintenance activities.
 127      *
 128      * May be null if 'stream' doesn't have anything to do here. */
 129     void (*run_wait)(struct stream *stream);
 130
 131     /* Arranges for the poll loop to wake up when 'stream' is ready to take an
 132      * action of the given 'type'. */
 133     void (*wait)(struct stream *stream, enum stream_wait_type type);
 134 };
 135 \f
 136 /* Passive listener for incoming stream connections.
 137  *
 138  * This structure should be treated as opaque by stream implementations. */
 139 struct pstream {
 140     const struct pstream_class *class;
 141     char *name;
 142     ovs_be16 bound_port;
 143 };
 144
 145 void pstream_init(struct pstream *, const struct pstream_class *, const char *name);
 146 void pstream_set_bound_port(struct pstream *, ovs_be16 bound_port);
 147 static inline void pstream_assert_class(const struct pstream *pstream,
 148                                         const struct pstream_class *class)
 149 {
 150     ovs_assert(pstream->class == class);
 151 }
 152
 153 struct pstream_class {
 154     /* Prefix for connection names, e.g. "ptcp", "pssl", "punix". */
 155     const char *name;
 156
 157     /* True if this pstream needs periodic probes to verify connectivity.  For
 158      * pstreams which need probes, it can take a long time to notice the
 159      * connection was dropped. */
 160     bool needs_probes;
 161
 162     /* Attempts to start listening for stream connections.  'name' is the full
 163      * connection name provided by the user, e.g. "ptcp:1234".  This name is
 164      * useful for error messages but must not be modified.
 165      *
 166      * 'suffix' is a copy of 'name' following the colon and may be modified.
 167      * 'dscp' is the DSCP value that the new connection should use in the IP
 168      * packets it sends.
 169      *
 170      * Returns 0 if successful, otherwise a positive errno value.  If
 171      * successful, stores a pointer to the new connection in '*pstreamp'.
 172      *
 173      * The listen function must not block.  If the connection cannot be
 174      * completed immediately, it should return EAGAIN (not EINPROGRESS, as
 175      * returned by the connect system call) and continue the connection in the
 176      * background. */
 177     int (*listen)(const char *name, char *suffix, struct pstream **pstreamp,
 178                   uint8_t dscp);
 179
 180     /* Closes 'pstream' and frees associated memory. */
 181     void (*close)(struct pstream *pstream);
 182
 183     /* Tries to accept a new connection on 'pstream'.  If successful, stores
 184      * the new connection in '*new_streamp' and returns 0.  Otherwise, returns
 185      * a positive errno value.
 186      *
 187      * The accept function must not block waiting for a connection.  If no
 188      * connection is ready to be accepted, it should return EAGAIN. */
 189     int (*accept)(struct pstream *pstream, struct stream **new_streamp);
 190
 191     /* Arranges for the poll loop to wake up when a connection is ready to be
 192      * accepted on 'pstream'. */
 193     void (*wait)(struct pstream *pstream);
 194
 195     /* Set DSCP value of the listening socket. */
 196     int (*set_dscp)(struct pstream *pstream, uint8_t dscp);
 197 };
 198
 199 /* Active and passive stream classes. */
 200 extern const struct stream_class tcp_stream_class;
 201 extern const struct pstream_class ptcp_pstream_class;
 202 extern const struct stream_class unix_stream_class;
 203 extern const struct pstream_class punix_pstream_class;
 204 #ifdef HAVE_OPENSSL
 205 extern const struct stream_class ssl_stream_class;
 206 extern const struct pstream_class pssl_pstream_class;
 207 #endif
 208
 209 #endif /* stream-provider.h */