src/core/xfer.c

   1 /*
   2  * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <string.h>
  22 #include <stdio.h>
  23 #include <errno.h>
  24 #include <gpxe/xfer.h>
  25
  26 /** @file
  27  *
  28  * Data transfer interfaces
  29  *
  30  */
  31
  32 /**
  33  * Dummy transfer metadata
  34  *
  35  * This gets passed to xfer_interface::deliver_iob() and equivalents
  36  * when no metadata is available.
  37  */
  38 static struct xfer_metadata dummy_metadata;
  39
  40 /**
  41  * Close data transfer interface
  42  *
  43  * @v xfer              Data transfer interface
  44  * @v rc                Reason for close
  45  */
  46 void xfer_close ( struct xfer_interface *xfer, int rc ) {
  47         struct xfer_interface *dest = xfer_get_dest ( xfer );
  48         struct xfer_interface_operations *op = xfer->op;
  49
  50         DBGC ( xfer, "XFER %p->%p close\n", xfer, dest );
  51
  52         xfer_unplug ( xfer );
  53         xfer_nullify ( xfer );
  54         dest->op->close ( dest, rc );
  55         xfer->op = op;
  56         xfer_put ( dest );
  57 }
  58
  59 /**
  60  * Send redirection event
  61  *
  62  * @v xfer              Data transfer interface
  63  * @v type              New location type
  64  * @v args              Remaining arguments depend upon location type
  65  * @ret rc              Return status code
  66  */
  67 int xfer_vredirect ( struct xfer_interface *xfer, int type, va_list args ) {
  68         struct xfer_interface *dest = xfer_get_dest ( xfer );
  69         int rc;
  70
  71         DBGC ( xfer, "XFER %p->%p redirect\n", xfer, dest );
  72
  73         rc = dest->op->vredirect ( dest, type, args );
  74
  75         if ( rc != 0 ) {
  76                 DBGC ( xfer, "XFER %p<-%p redirect: %s\n", xfer, dest,
  77                        strerror ( rc ) );
  78         }
  79         xfer_put ( dest );
  80         return rc;
  81 }
  82
  83 /**
  84  * Send redirection event
  85  *
  86  * @v xfer              Data transfer interface
  87  * @v type              New location type
  88  * @v ...               Remaining arguments depend upon location type
  89  * @ret rc              Return status code
  90  */
  91 int xfer_redirect ( struct xfer_interface *xfer, int type, ... ) {
  92         va_list args;
  93         int rc;
  94
  95         va_start ( args, type );
  96         rc = xfer_vredirect ( xfer, type, args );
  97         va_end ( args );
  98         return rc;
  99 }
 100
 101 /**
 102  * Check flow control window
 103  *
 104  * @v xfer              Data transfer interface
 105  * @ret len             Length of window
 106  */
 107 size_t xfer_window ( struct xfer_interface *xfer ) {
 108         struct xfer_interface *dest = xfer_get_dest ( xfer );
 109         size_t len;
 110
 111         len = dest->op->window ( dest );
 112
 113         xfer_put ( dest );
 114         return len;
 115 }
 116
 117 /**
 118  * Allocate I/O buffer
 119  *
 120  * @v xfer              Data transfer interface
 121  * @v len               I/O buffer payload length
 122  * @ret iobuf           I/O buffer
 123  */
 124 struct io_buffer * xfer_alloc_iob ( struct xfer_interface *xfer, size_t len ) {
 125         struct xfer_interface *dest = xfer_get_dest ( xfer );
 126         struct io_buffer *iobuf;
 127
 128         DBGC ( xfer, "XFER %p->%p alloc_iob %zd\n", xfer, dest, len );
 129
 130         iobuf = dest->op->alloc_iob ( dest, len );
 131
 132         if ( ! iobuf ) {
 133                 DBGC ( xfer, "XFER %p<-%p alloc_iob failed\n", xfer, dest );
 134         }
 135         xfer_put ( dest );
 136         return iobuf;
 137 }
 138
 139 /**
 140  * Deliver datagram as I/O buffer with metadata
 141  *
 142  * @v xfer              Data transfer interface
 143  * @v iobuf             Datagram I/O buffer
 144  * @v meta              Data transfer metadata
 145  * @ret rc              Return status code
 146  */
 147 int xfer_deliver_iob_meta ( struct xfer_interface *xfer,
 148                             struct io_buffer *iobuf,
 149                             struct xfer_metadata *meta ) {
 150         struct xfer_interface *dest = xfer_get_dest ( xfer );
 151         int rc;
 152
 153         DBGC ( xfer, "XFER %p->%p deliver_iob %zd\n", xfer, dest,
 154                iob_len ( iobuf ) );
 155
 156         rc = dest->op->deliver_iob ( dest, iobuf, meta );
 157
 158         if ( rc != 0 ) {
 159                 DBGC ( xfer, "XFER %p<-%p deliver_iob: %s\n", xfer, dest,
 160                        strerror ( rc ) );
 161         }
 162         xfer_put ( dest );
 163         return rc;
 164 }
 165
 166 /**
 167  * Deliver datagram as I/O buffer with metadata
 168  *
 169  * @v xfer              Data transfer interface
 170  * @v iobuf             Datagram I/O buffer
 171  * @ret rc              Return status code
 172  */
 173 int xfer_deliver_iob ( struct xfer_interface *xfer,
 174                        struct io_buffer *iobuf ) {
 175         return xfer_deliver_iob_meta ( xfer, iobuf, &dummy_metadata );
 176 }
 177
 178 /**
 179  * Deliver datagram as raw data
 180  *
 181  * @v xfer              Data transfer interface
 182  * @v iobuf             Datagram I/O buffer
 183  * @ret rc              Return status code
 184  */
 185 int xfer_deliver_raw ( struct xfer_interface *xfer,
 186                        const void *data, size_t len ) {
 187         struct xfer_interface *dest = xfer_get_dest ( xfer );
 188         int rc;
 189
 190         DBGC ( xfer, "XFER %p->%p deliver_raw %p+%zd\n", xfer, dest,
 191                data, len );
 192
 193         rc = dest->op->deliver_raw ( dest, data, len );
 194
 195         if ( rc != 0 ) {
 196                 DBGC ( xfer, "XFER %p<-%p deliver_raw: %s\n", xfer, dest,
 197                        strerror ( rc ) );
 198         }
 199         xfer_put ( dest );
 200         return rc;
 201 }
 202
 203 /**
 204  * Deliver formatted string
 205  *
 206  * @v xfer              Data transfer interface
 207  * @v format            Format string
 208  * @v args              Arguments corresponding to the format string
 209  * @ret rc              Return status code
 210  */
 211 int xfer_vprintf ( struct xfer_interface *xfer, const char *format,
 212                    va_list args ) {
 213         size_t len;
 214         va_list args_tmp;
 215
 216         va_copy ( args_tmp, args );
 217         len = vsnprintf ( NULL, 0, format, args );
 218         {
 219                 char buf[len + 1];
 220                 vsnprintf ( buf, sizeof ( buf ), format, args_tmp );
 221                 va_end ( args_tmp );
 222                 return xfer_deliver_raw ( xfer, buf, len );
 223         }
 224 }
 225
 226 /**
 227  * Deliver formatted string
 228  *
 229  * @v xfer              Data transfer interface
 230  * @v format            Format string
 231  * @v ...               Arguments corresponding to the format string
 232  * @ret rc              Return status code
 233  */
 234 int xfer_printf ( struct xfer_interface *xfer, const char *format, ... ) {
 235         va_list args;
 236         int rc;
 237
 238         va_start ( args, format );
 239         rc = xfer_vprintf ( xfer, format, args );
 240         va_end ( args );
 241         return rc;
 242 }
 243
 244 /**
 245  * Seek to position
 246  *
 247  * @v xfer              Data transfer interface
 248  * @v offset            Offset to new position
 249  * @v whence            Basis for new position
 250  * @ret rc              Return status code
 251  */
 252 int xfer_seek ( struct xfer_interface *xfer, off_t offset, int whence ) {
 253         struct io_buffer *iobuf;
 254         struct xfer_metadata meta = {
 255                 .offset = offset,
 256                 .whence = whence,
 257         };
 258
 259         DBGC ( xfer, "XFER %p seek %s+%ld\n", xfer,
 260                whence_text ( whence ), offset );
 261
 262         /* Allocate and send a zero-length data buffer */
 263         iobuf = xfer_alloc_iob ( xfer, 0 );
 264         if ( ! iobuf )
 265                 return -ENOMEM;
 266         return xfer_deliver_iob_meta ( xfer, iobuf, &meta );
 267 }
 268
 269 /****************************************************************************
 270  *
 271  * Helper methods
 272  *
 273  * These functions are designed to be used as methods in the
 274  * xfer_interface_operations table.
 275  *
 276  */
 277
 278 /**
 279  * Ignore close() event
 280  *
 281  * @v xfer              Data transfer interface
 282  * @v rc                Reason for close
 283  */
 284 void ignore_xfer_close ( struct xfer_interface *xfer __unused,
 285                          int rc __unused ) {
 286         /* Nothing to do */
 287 }
 288
 289 /**
 290  * Ignore vredirect() event
 291  *
 292  * @v xfer              Data transfer interface
 293  * @v type              New location type
 294  * @v args              Remaining arguments depend upon location type
 295  * @ret rc              Return status code
 296  */
 297 int ignore_xfer_vredirect ( struct xfer_interface *xfer __unused,
 298                             int type __unused, va_list args __unused ) {
 299         return 0;
 300 }
 301
 302 /**
 303  * Unlimited flow control window
 304  *
 305  * @v xfer              Data transfer interface
 306  * @ret len             Length of window
 307  *
 308  * This handler indicates that the interface is always ready to accept
 309  * data.
 310  */
 311 size_t unlimited_xfer_window ( struct xfer_interface *xfer __unused ) {
 312         return ~( ( size_t ) 0 );
 313 }
 314
 315 /**
 316  * No flow control window
 317  *
 318  * @v xfer              Data transfer interface
 319  * @ret len             Length of window
 320  *
 321  * This handler indicates that the interface is never ready to accept
 322  * data.
 323  */
 324 size_t no_xfer_window ( struct xfer_interface *xfer __unused ) {
 325         return 0;
 326 }
 327
 328 /**
 329  * Allocate I/O buffer
 330  *
 331  * @v xfer              Data transfer interface
 332  * @v len               I/O buffer payload length
 333  * @ret iobuf           I/O buffer
 334  */
 335 struct io_buffer *
 336 default_xfer_alloc_iob ( struct xfer_interface *xfer __unused, size_t len ) {
 337         return alloc_iob ( len );
 338 }
 339
 340 /**
 341  * Deliver datagram as raw data
 342  *
 343  * @v xfer              Data transfer interface
 344  * @v iobuf             Datagram I/O buffer
 345  * @v meta              Data transfer metadata
 346  * @ret rc              Return status code
 347  *
 348  * This function is intended to be used as the deliver() method for
 349  * data transfer interfaces that prefer to handle raw data.
 350  */
 351 int xfer_deliver_as_raw ( struct xfer_interface *xfer,
 352                           struct io_buffer *iobuf,
 353                           struct xfer_metadata *meta __unused ) {
 354         int rc;
 355
 356         rc = xfer->op->deliver_raw ( xfer, iobuf->data, iob_len ( iobuf ) );
 357         free_iob ( iobuf );
 358         return rc;
 359 }
 360
 361 /**
 362  * Deliver datagram as I/O buffer
 363  *
 364  * @v xfer              Data transfer interface
 365  * @v data              Data buffer
 366  * @v len               Length of data buffer
 367  * @ret rc              Return status code
 368  *
 369  * This function is intended to be used as the deliver_raw() method
 370  * for data transfer interfaces that prefer to handle I/O buffers.
 371  */
 372 int xfer_deliver_as_iob ( struct xfer_interface *xfer,
 373                           const void *data, size_t len ) {
 374         struct io_buffer *iobuf;
 375
 376         iobuf = xfer->op->alloc_iob ( xfer, len );
 377         if ( ! iobuf )
 378                 return -ENOMEM;
 379
 380         memcpy ( iob_put ( iobuf, len ), data, len );
 381         return xfer->op->deliver_iob ( xfer, iobuf, &dummy_metadata );
 382 }
 383
 384 /**
 385  * Ignore datagram as raw data event
 386  *
 387  * @v xfer              Data transfer interface
 388  * @v data              Data buffer
 389  * @v len               Length of data buffer
 390  * @ret rc              Return status code
 391  */
 392 int ignore_xfer_deliver_raw ( struct xfer_interface *xfer,
 393                               const void *data __unused, size_t len ) {
 394         DBGC ( xfer, "XFER %p %zd bytes delivered %s\n", xfer, len,
 395                ( ( xfer == &null_xfer ) ?
 396                  "before connection" : "after termination" ) );
 397         return 0;
 398 }
 399
 400 /** Null data transfer interface operations */
 401 struct xfer_interface_operations null_xfer_ops = {
 402         .close          = ignore_xfer_close,
 403         .vredirect      = ignore_xfer_vredirect,
 404         .window         = unlimited_xfer_window,
 405         .alloc_iob      = default_xfer_alloc_iob,
 406         .deliver_iob    = xfer_deliver_as_raw,
 407         .deliver_raw    = ignore_xfer_deliver_raw,
 408 };
 409
 410 /**
 411  * Null data transfer interface
 412  *
 413  * This is the interface to which data transfer interfaces are
 414  * connected when unplugged.  It will never generate messages, and
 415  * will silently absorb all received messages.
 416  */
 417 struct xfer_interface null_xfer = XFER_INIT ( &null_xfer_ops );