lib/stream-fd.c

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