lib/stream-fd.c

   1 /*
   2  * Copyright (c) 2008, 2009, 2010, 2012, 2013, 2014 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 #include <config.h>
  18 #include "stream-fd.h"
  19 #include <errno.h>
  20 #include <poll.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/socket.h>
  24 #include <sys/types.h>
  25 #include <unistd.h>
  26 #include "fatal-signal.h"
  27 #include "poll-loop.h"
  28 #include "socket-util.h"
  29 #include "util.h"
  30 #include "stream-provider.h"
  31 #include "stream.h"
  32 #include "openvswitch/vlog.h"
  33
  34 VLOG_DEFINE_THIS_MODULE(stream_fd);
  35
  36 /* Active file descriptor stream. */
  37
  38 struct stream_fd
  39 {
  40     struct stream stream;
  41     int fd;
  42     int fd_type;
  43 };
  44
  45 static const struct stream_class stream_fd_class;
  46
  47 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(10, 25);
  48
  49 static void maybe_unlink_and_free(char *path);
  50
  51 /* Creates a new stream named 'name' that will send and receive data on 'fd'
  52  * and stores a pointer to the stream in '*streamp'.  Initial connection status
  53  * 'connect_status' is interpreted as described for stream_init(). 'fd_type'
  54  * tells whether the socket is TCP or Unix domain socket.
  55  *
  56  * Returns 0 if successful, otherwise a positive errno value.  (The current
  57  * implementation never fails.) */
  58 int
  59 new_fd_stream(const char *name, int fd, int connect_status, int fd_type,
  60               struct stream **streamp)
  61 {
  62     struct stream_fd *s;
  63
  64     s = xmalloc(sizeof *s);
  65     stream_init(&s->stream, &stream_fd_class, connect_status, name);
  66     s->fd = fd;
  67     s->fd_type = fd_type;
  68     *streamp = &s->stream;
  69     return 0;
  70 }
  71
  72 static struct stream_fd *
  73 stream_fd_cast(struct stream *stream)
  74 {
  75     stream_assert_class(stream, &stream_fd_class);
  76     return CONTAINER_OF(stream, struct stream_fd, stream);
  77 }
  78
  79 static void
  80 fd_close(struct stream *stream)
  81 {
  82     struct stream_fd *s = stream_fd_cast(stream);
  83     closesocket(s->fd);
  84     free(s);
  85 }
  86
  87 static int
  88 fd_connect(struct stream *stream)
  89 {
  90     struct stream_fd *s = stream_fd_cast(stream);
  91     int retval = check_connection_completion(s->fd);
  92     if (retval == 0 && s->fd_type == AF_INET) {
  93         setsockopt_tcp_nodelay(s->fd);
  94     }
  95     return retval;
  96 }
  97
  98 static ssize_t
  99 fd_recv(struct stream *stream, void *buffer, size_t n)
 100 {
 101     struct stream_fd *s = stream_fd_cast(stream);
 102     ssize_t retval;
 103     int error;
 104
 105     retval = recv(s->fd, buffer, n, 0);
 106     if (retval < 0) {
 107         error = sock_errno();
 108 #ifdef _WIN32
 109         if (error == WSAEWOULDBLOCK) {
 110            error = EAGAIN;
 111         }
 112 #endif
 113         if (error != EAGAIN) {
 114             VLOG_DBG_RL(&rl, "recv: %s", sock_strerror(error));
 115         }
 116         return -error;
 117     }
 118     return retval;
 119 }
 120
 121 static ssize_t
 122 fd_send(struct stream *stream, const void *buffer, size_t n)
 123 {
 124     struct stream_fd *s = stream_fd_cast(stream);
 125     ssize_t retval;
 126     int error;
 127
 128     retval = send(s->fd, buffer, n, 0);
 129     if (retval < 0) {
 130         error = sock_errno();
 131 #ifdef _WIN32
 132         if (error == WSAEWOULDBLOCK) {
 133            error = EAGAIN;
 134         }
 135 #endif
 136         if (error != EAGAIN) {
 137             VLOG_DBG_RL(&rl, "recv: %s", sock_strerror(error));
 138         }
 139         return -error;
 140     }
 141     return (retval > 0 ? retval : -EAGAIN);
 142 }
 143
 144 static void
 145 fd_wait(struct stream *stream, enum stream_wait_type wait)
 146 {
 147     struct stream_fd *s = stream_fd_cast(stream);
 148     switch (wait) {
 149     case STREAM_CONNECT:
 150     case STREAM_SEND:
 151         poll_fd_wait(s->fd, POLLOUT);
 152         break;
 153
 154     case STREAM_RECV:
 155         poll_fd_wait(s->fd, POLLIN);
 156         break;
 157
 158     default:
 159         OVS_NOT_REACHED();
 160     }
 161 }
 162
 163 static const struct stream_class stream_fd_class = {
 164     "fd",                       /* name */
 165     false,                      /* needs_probes */
 166     NULL,                       /* open */
 167     fd_close,                   /* close */
 168     fd_connect,                 /* connect */
 169     fd_recv,                    /* recv */
 170     fd_send,                    /* send */
 171     NULL,                       /* run */
 172     NULL,                       /* run_wait */
 173     fd_wait,                    /* wait */
 174 };
 175 \f
 176 /* Passive file descriptor stream. */
 177
 178 struct fd_pstream
 179 {
 180     struct pstream pstream;
 181     int fd;
 182     int (*accept_cb)(int fd, const struct sockaddr_storage *, size_t ss_len,
 183                      struct stream **);
 184     int (*set_dscp_cb)(int fd, uint8_t dscp);
 185     char *unlink_path;
 186 };
 187
 188 static const struct pstream_class fd_pstream_class;
 189
 190 static struct fd_pstream *
 191 fd_pstream_cast(struct pstream *pstream)
 192 {
 193     pstream_assert_class(pstream, &fd_pstream_class);
 194     return CONTAINER_OF(pstream, struct fd_pstream, pstream);
 195 }
 196
 197 /* Creates a new pstream named 'name' that will accept new socket connections
 198  * on 'fd' and stores a pointer to the stream in '*pstreamp'.
 199  *
 200  * When a connection has been accepted, 'accept_cb' will be called with the new
 201  * socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
 202  * accept_cb must return 0 if the connection is successful, in which case it
 203  * must initialize '*streamp' to the new stream, or a positive errno value on
 204  * error.  In either case accept_cb takes ownership of the 'fd' passed in.
 205  *
 206  * When '*pstreamp' is closed, then 'unlink_path' (if nonnull) will be passed
 207  * to fatal_signal_unlink_file_now() and freed with free().
 208  *
 209  * Returns 0 if successful, otherwise a positive errno value.  (The current
 210  * implementation never fails.) */
 211 int
 212 new_fd_pstream(const char *name, int fd,
 213                int (*accept_cb)(int fd, const struct sockaddr_storage *ss,
 214                                 size_t ss_len, struct stream **streamp),
 215                int (*set_dscp_cb)(int fd, uint8_t dscp),
 216                char *unlink_path, struct pstream **pstreamp)
 217 {
 218     struct fd_pstream *ps = xmalloc(sizeof *ps);
 219     pstream_init(&ps->pstream, &fd_pstream_class, name);
 220     ps->fd = fd;
 221     ps->accept_cb = accept_cb;
 222     ps->set_dscp_cb = set_dscp_cb;
 223     ps->unlink_path = unlink_path;
 224     *pstreamp = &ps->pstream;
 225     return 0;
 226 }
 227
 228 static void
 229 pfd_close(struct pstream *pstream)
 230 {
 231     struct fd_pstream *ps = fd_pstream_cast(pstream);
 232     closesocket(ps->fd);
 233     maybe_unlink_and_free(ps->unlink_path);
 234     free(ps);
 235 }
 236
 237 static int
 238 pfd_accept(struct pstream *pstream, struct stream **new_streamp)
 239 {
 240     struct fd_pstream *ps = fd_pstream_cast(pstream);
 241     struct sockaddr_storage ss;
 242     socklen_t ss_len = sizeof ss;
 243     int new_fd;
 244     int retval;
 245
 246     new_fd = accept(ps->fd, (struct sockaddr *) &ss, &ss_len);
 247     if (new_fd < 0) {
 248         retval = sock_errno();
 249 #ifdef _WIN32
 250         if (retval == WSAEWOULDBLOCK) {
 251             retval = EAGAIN;
 252         }
 253 #endif
 254         if (retval != EAGAIN) {
 255             VLOG_DBG_RL(&rl, "accept: %s", sock_strerror(retval));
 256         }
 257         return retval;
 258     }
 259
 260     retval = set_nonblocking(new_fd);
 261     if (retval) {
 262         closesocket(new_fd);
 263         return retval;
 264     }
 265
 266     return ps->accept_cb(new_fd, &ss, ss_len, new_streamp);
 267 }
 268
 269 static void
 270 pfd_wait(struct pstream *pstream)
 271 {
 272     struct fd_pstream *ps = fd_pstream_cast(pstream);
 273     poll_fd_wait(ps->fd, POLLIN);
 274 }
 275
 276 static int
 277 pfd_set_dscp(struct pstream *pstream, uint8_t dscp)
 278 {
 279     struct fd_pstream *ps = fd_pstream_cast(pstream);
 280     if (ps->set_dscp_cb) {
 281         return ps->set_dscp_cb(ps->fd, dscp);
 282     }
 283     return 0;
 284 }
 285
 286 static const struct pstream_class fd_pstream_class = {
 287     "pstream",
 288     false,
 289     NULL,
 290     pfd_close,
 291     pfd_accept,
 292     pfd_wait,
 293     pfd_set_dscp,
 294 };
 295 \f
 296 /* Helper functions. */
 297 static void
 298 maybe_unlink_and_free(char *path)
 299 {
 300     if (path) {
 301         fatal_signal_unlink_file_now(path);
 302         free(path);
 303     }
 304 }