net/cor/forward.c

   1 /*
   2  *      Connection oriented routing
   3  *      Copyright (C) 2007-2008 Michael Blizek
   4  *
   5  *      This program is free software; you can redistribute it and/or
   6  *      modify it under the terms of the GNU General Public License
   7  *      as published by the Free Software Foundation; either version 2
   8  *      of the License, or (at your option) any later version.
   9  *
  10  *      This program is distributed in the hope that it will be useful,
  11  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *      GNU General Public License for more details.
  14  *
  15  *      You should have received a copy of the GNU General Public License
  16  *      along with this program; if not, write to the Free Software
  17  *      Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  *      02110-1301, USA.
  19  */
  20
  21 #include <linux/mutex.h>
  22
  23 #include "cor.h"
  24
  25 struct kmem_cache *data_buf_item_slab;
  26
  27 #define PAGESIZE (1 << PAGE_SHIFT)
  28
  29 void databuf_init(struct data_buf *data)
  30 {
  31         memset(data, 0, sizeof(struct data_buf));
  32         INIT_LIST_HEAD(&(data->items));
  33 }
  34
  35 static void databuf_item_free(struct data_buf_item *item)
  36 {
  37         if (item->type == TYPE_BUF) {
  38                 kfree(item->data.buf.buf);
  39         } else if (item->type == TYPE_SKB) {
  40                 kfree_skb(item->data.skb);
  41         } else {
  42                 BUG();
  43         }
  44
  45         list_del(&(item->buf_list));
  46
  47         kmem_cache_free(data_buf_item_slab, item);
  48 }
  49
  50 void reset_seqno(struct data_buf *buf)
  51 {
  52         buf->first_offset = 0 - buf->last_read_offset;
  53 }
  54
  55 void databuf_free(struct data_buf *data)
  56 {
  57         while (!list_empty(&(data->items))) {
  58                 struct data_buf_item *item = container_of(data->items.next,
  59                                 struct data_buf_item, buf_list);
  60                 databuf_item_free(item);
  61         }
  62 }
  63
  64 static void databuf_nextreadchunk(struct data_buf *data)
  65 {
  66         if (data->lastread == 0) {
  67                 BUG_ON(data->last_read_offset != 0);
  68                 BUG_ON(list_empty(&(data->items)));
  69                 data->lastread = container_of(data->items.next,
  70                                 struct data_buf_item, buf_list);
  71         } else if (&(data->lastread->buf_list) != data->items.prev) {
  72                 data->lastread = container_of(data->lastread->buf_list.next,
  73                                 struct data_buf_item, buf_list);
  74
  75                 data->last_read_offset = 0;
  76         }
  77 }
  78
  79 static int _databuf_pull(struct data_buf *data, char *dst, int len, int userbuf)
  80 {
  81         int totalcpy = 0;
  82
  83         BUG_ON(data->read_remaining < len);
  84
  85         if (data->lastread == 0)
  86                 databuf_nextreadchunk(data);
  87
  88         while(len > 0) {
  89                 int rc = 0;
  90                 int cpy = len;
  91
  92                 char *srcbuf = 0;
  93                 int srcbuflen = 0;
  94
  95                 char *srcbufcpystart = 0;
  96                 int srcbufcpylen = 0;
  97
  98                 BUG_ON(data->lastread == 0);
  99
 100                 if (data->lastread->type == TYPE_BUF) {
 101                         srcbuf = data->lastread->data.buf.buf;
 102                         srcbuflen = data->lastread->data.buf.datalen;
 103                 } else if (data->lastread->type == TYPE_SKB) {
 104                         srcbuf = data->lastread->data.skb->data;
 105                         srcbuflen = data->lastread->data.skb->len;
 106                 } else {
 107                         BUG();
 108                 }
 109
 110                 srcbufcpystart = srcbuf + data->last_read_offset;
 111                 srcbufcpylen = srcbuflen - data->last_read_offset;
 112
 113                 if (cpy > srcbufcpylen)
 114                         cpy = srcbufcpylen;
 115
 116                 if (userbuf) {
 117                         int notcopied = copy_to_user(dst, srcbufcpystart, cpy);
 118                         cpy -= notcopied;
 119                         if (unlikely(notcopied > 0))
 120                                 rc = -EFAULT;
 121                 } else {
 122                         memcpy(dst, srcbufcpystart, cpy);
 123                 }
 124
 125                 dst += cpy;
 126                 len -= cpy;
 127                 totalcpy += cpy;
 128
 129                 data->read_remaining -= cpy;
 130                 data->last_read_offset += cpy;
 131
 132                 if (cpy == srcbufcpylen)
 133                         databuf_nextreadchunk(data);
 134
 135                 if (unlikely(rc < 0)) {
 136                         if (totalcpy == 0)
 137                                 totalcpy = rc;
 138                         break;
 139                 }
 140         }
 141
 142         return totalcpy;
 143 }
 144
 145 void databuf_pull(struct data_buf *data, char *dst, int len)
 146 {
 147         _databuf_pull(data, dst, len, 0);
 148 }
 149
 150 size_t databuf_pulluser(struct conn *sconn, struct msghdr *msg)
 151 {
 152         size_t copied = 0;
 153         int iovidx = 0;
 154         int iovread = 0;
 155
 156         while (iovidx < msg->msg_iovlen) {
 157                 int rc;
 158
 159                 struct iovec *iov = msg->msg_iov + iovidx;
 160                 __user char *msg = iov->iov_base + iovread;
 161                 unsigned int len = iov->iov_len - iovread;
 162
 163                 if (len == 0) {
 164                         iovidx++;
 165                         iovread = 0;
 166                         continue;
 167                 }
 168
 169                 if (sconn->buf.read_remaining == 0) {
 170                         if (sconn->sourcetype == SOURCE_NONE)
 171                                 rc = -EPIPE;
 172                         else
 173                                 rc = -EAGAIN;
 174                 } else {
 175                         if (len > sconn->buf.read_remaining)
 176                                 len = sconn->buf.read_remaining;
 177
 178                         rc = _databuf_pull(&(sconn->buf), msg, len, 1);
 179                 }
 180
 181                 BUG_ON(rc == 0);
 182
 183                 if (rc < 0) {
 184                         if (copied == 0)
 185                                 copied = rc;
 186                         break;
 187                 }
 188
 189                 copied += rc;
 190                 iovread += rc;
 191         }
 192
 193         return copied;
 194 }
 195
 196 void databuf_unpull(struct data_buf *data, __u32 bytes)
 197 {
 198         data->read_remaining += bytes;
 199
 200         BUG_ON(data->lastread == 0);
 201
 202         while (bytes > data->last_read_offset) {
 203                 bytes -= data->last_read_offset;
 204                 data->lastread = container_of(data->lastread->buf_list.prev,
 205                                 struct data_buf_item, buf_list);
 206                 BUG_ON(&(data->lastread->buf_list) == &(data->items));
 207         }
 208
 209         data->last_read_offset -= bytes;
 210 }
 211
 212 void databuf_pullold(struct data_buf *data, __u32 startpos, char *dst, int len)
 213 {
 214         __u32 pos = data->first_offset;
 215         struct data_buf_item *dbi = container_of(data->items.next,
 216                         struct data_buf_item, buf_list);
 217
 218         while(1) {
 219                 int srcbuflen;
 220
 221                 BUG_ON(&(dbi->buf_list) == &(data->items));
 222
 223                 if (data->lastread->type == TYPE_BUF) {
 224                         srcbuflen = dbi->data.buf.datalen;
 225                 } else if (data->lastread->type == TYPE_SKB) {
 226                         srcbuflen = dbi->data.skb->len;
 227                 } else {
 228                         BUG();
 229                 }
 230
 231                 if (((__s32) (pos + srcbuflen - startpos)) > 0)
 232                         break;
 233
 234                 pos += srcbuflen;
 235                 dbi = container_of(dbi->buf_list.next, struct data_buf_item,
 236                                 buf_list);
 237         }
 238
 239         while (len > 0) {
 240                 int cpy = len;
 241
 242                 char *srcbuf = 0;
 243                 int srcbuflen = 0;
 244
 245                 char *srcbufcpystart = 0;
 246                 int srcbufcpylen = 0;
 247
 248                 BUG_ON(&(dbi->buf_list) == &(data->items));
 249
 250                 if (data->lastread->type == TYPE_BUF) {
 251                         srcbuf = data->lastread->data.buf.buf;
 252                         srcbuflen = data->lastread->data.buf.datalen;
 253                 } else if (data->lastread->type == TYPE_SKB) {
 254                         srcbuf = data->lastread->data.skb->data;
 255                         srcbuflen = data->lastread->data.skb->len;
 256                 } else {
 257                         BUG();
 258                 }
 259
 260                 BUG_ON(((__s32) (pos - startpos)) > 0);
 261
 262                 srcbufcpystart = srcbuf + ((__s32) (startpos - pos));
 263                 srcbufcpylen = srcbuflen - ((__s32) (startpos - pos));
 264
 265                 if (cpy > srcbufcpylen)
 266                         cpy = srcbufcpylen;
 267
 268                 memcpy(dst, srcbufcpystart, cpy);
 269
 270                 dst += cpy;
 271                 len -= cpy;
 272                 startpos += cpy;
 273
 274                 pos += srcbuflen;
 275                 dbi = container_of(dbi->buf_list.next, struct data_buf_item,
 276                                 buf_list);
 277         }
 278 }
 279
 280 /* ack up to *not* including pos */
 281 void databuf_ack(struct conn *rconn, __u32 pos)
 282 {
 283         __u32 acked = 0;
 284         struct data_buf *buf = &(rconn->buf);
 285
 286         while (!list_empty(&(buf->items))) {
 287                 struct data_buf_item *firstitem = container_of(buf->items.next,
 288                                 struct data_buf_item, buf_list);
 289                 int firstlen = 0;
 290
 291                 if (firstitem == buf->lastread)
 292                         break;
 293
 294                 if (firstitem->type == TYPE_BUF) {
 295                         firstlen = firstitem->data.buf.datalen;
 296                 } else if (firstitem->type == TYPE_SKB) {
 297                         firstlen = firstitem->data.skb->len;
 298                 } else {
 299                         BUG();
 300                 }
 301
 302                 if (((__s32)(buf->first_offset + firstlen - pos)) > 0)
 303                         break;
 304
 305                 buf->first_offset += firstlen;
 306                 acked += firstlen;
 307
 308                 databuf_item_free(firstitem);
 309         }
 310
 311         if (rconn-> sourcetype == SOURCE_IN)
 312                 refresh_speedstat(rconn, acked);
 313 }
 314
 315 void databuf_ackread(struct conn *rconn)
 316 {
 317         __u32 acked = 0;
 318         struct data_buf *buf = &(rconn->buf);
 319
 320         while (!list_empty(&(buf->items)) && buf->lastread != 0) {
 321                 struct data_buf_item *firstitem = container_of(buf->items.next,
 322                                 struct data_buf_item, buf_list);
 323
 324                 if (firstitem == buf->lastread)
 325                         break;
 326
 327                 if (firstitem->type == TYPE_BUF) {
 328                         buf->first_offset += firstitem->data.buf.datalen;
 329                         acked += firstitem->data.buf.datalen;
 330                 } else if (firstitem->type == TYPE_SKB) {
 331                         buf->first_offset += firstitem->data.skb->len;
 332                         acked += firstitem->data.skb->len;
 333                 } else {
 334                         BUG();
 335                 }
 336
 337                 databuf_item_free(firstitem);
 338         }
 339
 340         if (rconn-> sourcetype == SOURCE_IN)
 341                 refresh_speedstat(rconn, acked);
 342 }
 343
 344 int databuf_maypush(struct data_buf *buf)
 345 {
 346         return 16384 - buf->read_remaining;
 347 }
 348
 349 void flush_buf(struct conn *rconn)
 350 {
 351         switch (rconn->targettype) {
 352         case TARGET_UNCONNECTED:
 353                 parse(rconn);
 354                 if (rconn->targettype != TARGET_UNCONNECTED)
 355                         flush_buf(rconn);
 356                 break;
 357         case TARGET_SOCK:
 358                 wake_up_interruptible(&(rconn->target.sock.wait));
 359                 break;
 360         case TARGET_OUT:
 361                 flush_out(rconn);
 362                 break;
 363         default:
 364                 BUG();
 365         }
 366 }
 367
 368 static int _receive_buf(struct conn *rconn, char *buf, int len, int userbuf)
 369 {
 370         struct data_buf_item *item = 0;
 371
 372         int totalcpy = 0;
 373
 374         BUG_ON(databuf_maypush(&(rconn->buf)) < len);
 375
 376         if (list_empty(&(rconn->buf.items)) == 0) {
 377                 struct list_head *last = rconn->buf.items.prev;
 378                 item = container_of(last, struct data_buf_item, buf_list);
 379
 380                 if (item->type != TYPE_BUF || rconn->buf.last_buflen <=
 381                                 item->data.buf.datalen)
 382                         item = 0;
 383         }
 384
 385         while (len > 0) {
 386                 int rc = 0;
 387                 int cpy = len;
 388                 if (item == 0) {
 389                         __u32 buflen = PAGESIZE;
 390                         if (buflen > 32768)
 391                                 buflen = 32768;
 392                         item = kmem_cache_alloc(data_buf_item_slab, GFP_KERNEL);
 393                         if (unlikely(item == 0)) {
 394                                 rc = -ENOMEM;
 395                                 goto error;
 396                         }
 397                         memset(item, 0, sizeof(item));
 398                         item->type = TYPE_BUF;
 399                         item->data.buf.buf = kmalloc(buflen, GFP_KERNEL);
 400
 401
 402                         if (unlikely(item->data.buf.buf == 0)) {
 403                                 kmem_cache_free(data_buf_item_slab, item);
 404                                 rc = -ENOMEM;
 405                                 goto error;
 406                         }
 407                         item->data.buf.datalen = 0;
 408                         list_add_tail(&(item->buf_list), &(rconn->buf.items));
 409                         rconn->buf.last_buflen = buflen;
 410                 }
 411
 412                 BUG_ON(item->type != TYPE_BUF);
 413                 BUG_ON(rconn->buf.last_buflen <= item->data.buf.datalen);
 414
 415                 if (rconn->buf.last_buflen - item->data.buf.datalen < cpy)
 416                         cpy = (rconn->buf.last_buflen - item->data.buf.datalen);
 417
 418                 if (userbuf) {
 419                         int notcopied = copy_from_user(item->data.buf.buf +
 420                                         item->data.buf.datalen, buf, cpy);
 421                         cpy -= notcopied;
 422                         if (unlikely(notcopied > 0))
 423                                 rc = -EFAULT;
 424                 } else {
 425                         memcpy(item->data.buf.buf + item->data.buf.datalen,
 426                                         buf, cpy);
 427                 }
 428
 429                 buf += cpy;
 430                 len -= cpy;
 431                 totalcpy += cpy;
 432
 433                 item->data.buf.datalen += cpy;
 434
 435 error:
 436                 if (unlikely(rc < 0)) {
 437                         if (totalcpy == 0)
 438                                 return rc;
 439                         break;
 440                 }
 441         }
 442
 443         rconn->buf.read_remaining += totalcpy;
 444
 445         return totalcpy;
 446 }
 447
 448 int receive_userbuf(struct conn *rconn, struct msghdr *msg)
 449 {
 450         int copied = 0;
 451         int iovidx = 0;
 452         int iovread = 0;
 453
 454         if (databuf_maypush(&(rconn->buf)) <= 0)
 455                 return -EAGAIN;
 456
 457         while (iovidx < msg->msg_iovlen) {
 458                 struct iovec *iov = msg->msg_iov + iovidx;
 459                 __user char *userbuf = iov->iov_base + iovread;
 460                 int len = iov->iov_len - iovread;
 461                 int rc;
 462                 int pushlimit;
 463
 464                 if (len == 0) {
 465                         iovidx++;
 466                         iovread = 0;
 467                         continue;
 468                 }
 469
 470                 pushlimit = databuf_maypush(&(rconn->buf));
 471
 472                 if (pushlimit <= 0) {
 473                         if (rconn->targettype == TARGET_UNCONNECTED)
 474                                 rc = -EPIPE;
 475                         else
 476                                 rc = -EAGAIN;
 477                 } else {
 478                         if (pushlimit < len)
 479                                 len = pushlimit;
 480
 481                         rc = _receive_buf(rconn, userbuf, len, 1);
 482                 }
 483
 484                 if (rc < 0) {
 485                         if (copied == 0)
 486                                 copied = rc;
 487                         break;
 488                 }
 489
 490                 copied += rc;
 491                 iovread += rc;
 492         }
 493
 494         if (copied > 0)
 495                 flush_buf(rconn);;
 496
 497         return copied;
 498 }
 499
 500 void receive_buf(struct conn *rconn, char *buf, int len)
 501 {
 502         BUG_ON(databuf_maypush(&(rconn->buf)) < len);
 503         _receive_buf(rconn, buf, len, 0);
 504         flush_buf(rconn);
 505 }
 506
 507 int receive_skb(struct conn *rconn, struct sk_buff *skb)
 508 {
 509         struct data_buf_item *item;
 510
 511         if (databuf_maypush(&(rconn->buf)) < skb->len)
 512                 return 1;
 513
 514         item = kmem_cache_alloc(data_buf_item_slab, GFP_KERNEL);
 515
 516         if (unlikely(item == 0))
 517                 return 1;
 518
 519         item->data.skb = skb;
 520         item->type = TYPE_SKB;
 521         list_add_tail(&(item->buf_list), &(rconn->buf.items));
 522         rconn->buf.read_remaining += skb->len;
 523         rconn->buf.last_buflen = 0;
 524
 525         flush_buf(rconn);
 526
 527         return 0;
 528 }
 529
 530 void wake_sender(struct conn *rconn)
 531 {
 532         switch (rconn->sourcetype) {
 533         case SOURCE_NONE:
 534                 /* nothing */
 535                 break;
 536         case SOURCE_SOCK:
 537                 wake_up_interruptible(&(rconn->source.sock.wait));
 538                 break;
 539         case SOURCE_IN:
 540                 drain_ooo_queue(rconn);
 541                 break;
 542         default:
 543                 BUG();
 544         }
 545 }
 546
 547 void forward_init(void)
 548 {
 549         data_buf_item_slab = kmem_cache_create("cor_data_buf_item",
 550                         sizeof(struct data_buf_item), 8, 0, 0);
 551 }