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 "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, "send: %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     char *unlink_path;
 185 };
 186
 187 static const struct pstream_class fd_pstream_class;
 188
 189 static struct fd_pstream *
 190 fd_pstream_cast(struct pstream *pstream)
 191 {
 192     pstream_assert_class(pstream, &fd_pstream_class);
 193     return CONTAINER_OF(pstream, struct fd_pstream, pstream);
 194 }
 195
 196 /* Creates a new pstream named 'name' that will accept new socket connections
 197  * on 'fd' and stores a pointer to the stream in '*pstreamp'.
 198  *
 199  * When a connection has been accepted, 'accept_cb' will be called with the new
 200  * socket fd 'fd' and the remote address of the connection 'sa' and 'sa_len'.
 201  * accept_cb must return 0 if the connection is successful, in which case it
 202  * must initialize '*streamp' to the new stream, or a positive errno value on
 203  * error.  In either case accept_cb takes ownership of the 'fd' passed in.
 204  *
 205  * When '*pstreamp' is closed, then 'unlink_path' (if nonnull) will be passed
 206  * to fatal_signal_unlink_file_now() and freed with free().
 207  *
 208  * Returns 0 if successful, otherwise a positive errno value.  (The current
 209  * implementation never fails.) */
 210 int
 211 new_fd_pstream(const char *name, int fd,
 212                int (*accept_cb)(int fd, const struct sockaddr_storage *ss,
 213                                 size_t ss_len, struct stream **streamp),
 214                char *unlink_path, struct pstream **pstreamp)
 215 {
 216     struct fd_pstream *ps = xmalloc(sizeof *ps);
 217     pstream_init(&ps->pstream, &fd_pstream_class, name);
 218     ps->fd = fd;
 219     ps->accept_cb = accept_cb;
 220     ps->unlink_path = unlink_path;
 221     *pstreamp = &ps->pstream;
 222     return 0;
 223 }
 224
 225 static void
 226 pfd_close(struct pstream *pstream)
 227 {
 228     struct fd_pstream *ps = fd_pstream_cast(pstream);
 229     closesocket(ps->fd);
 230     maybe_unlink_and_free(ps->unlink_path);
 231     free(ps);
 232 }
 233
 234 static int
 235 pfd_accept(struct pstream *pstream, struct stream **new_streamp)
 236 {
 237     struct fd_pstream *ps = fd_pstream_cast(pstream);
 238     struct sockaddr_storage ss;
 239     socklen_t ss_len = sizeof ss;
 240     int new_fd;
 241     int retval;
 242
 243     new_fd = accept(ps->fd, (struct sockaddr *) &ss, &ss_len);
 244     if (new_fd < 0) {
 245         retval = sock_errno();
 246 #ifdef _WIN32
 247         if (retval == WSAEWOULDBLOCK) {
 248             retval = EAGAIN;
 249         }
 250 #endif
 251         if (retval != EAGAIN) {
 252             VLOG_DBG_RL(&rl, "accept: %s", sock_strerror(retval));
 253         }
 254         return retval;
 255     }
 256
 257     retval = set_nonblocking(new_fd);
 258     if (retval) {
 259         closesocket(new_fd);
 260         return retval;
 261     }
 262
 263     return ps->accept_cb(new_fd, &ss, ss_len, new_streamp);
 264 }
 265
 266 static void
 267 pfd_wait(struct pstream *pstream)
 268 {
 269     struct fd_pstream *ps = fd_pstream_cast(pstream);
 270     poll_fd_wait(ps->fd, POLLIN);
 271 }
 272
 273 static const struct pstream_class fd_pstream_class = {
 274     "pstream",
 275     false,
 276     NULL,
 277     pfd_close,
 278     pfd_accept,
 279     pfd_wait,
 280 };
 281 \f
 282 /* Helper functions. */
 283 static void
 284 maybe_unlink_and_free(char *path)
 285 {
 286     if (path) {
 287         fatal_signal_unlink_file_now(path);
 288         free(path);
 289     }
 290 }