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 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 data_buf *buf, __u32 pos)
 282 {
 283         while (!list_empty(&(buf->items))) {
 284                 struct data_buf_item *firstitem = container_of(buf->items.next,
 285                                 struct data_buf_item, buf_list);
 286                 int firstlen = 0;
 287
 288                 if (firstitem == buf->lastread)
 289                         break;
 290
 291                 if (firstitem->type == TYPE_BUF) {
 292                         firstlen = firstitem->data.buf.datalen;
 293                 } else if (firstitem->type == TYPE_SKB) {
 294                         firstlen = firstitem->data.skb->len;
 295                 } else {
 296                         BUG();
 297                 }
 298
 299                 if (((__s32)(buf->first_offset + firstlen - pos)) > 0)
 300                         break;
 301
 302                 buf->first_offset += firstlen;
 303
 304                 databuf_item_free(firstitem);
 305         }
 306 }
 307
 308 void databuf_ackread(struct data_buf *buf)
 309 {
 310         while (!list_empty(&(buf->items)) && buf->lastread != 0) {
 311                 struct data_buf_item *firstitem = container_of(buf->items.next,
 312                                 struct data_buf_item, buf_list);
 313
 314                 if (firstitem == buf->lastread)
 315                         break;
 316
 317                 if (firstitem->type == TYPE_BUF) {
 318                         buf->first_offset += firstitem->data.buf.datalen;
 319                 } else if (firstitem->type == TYPE_SKB) {
 320                         buf->first_offset += firstitem->data.skb->len;
 321                 } else {
 322                         BUG();
 323                 }
 324
 325                 databuf_item_free(firstitem);
 326         }
 327 }
 328
 329 int databuf_maypush(struct data_buf *buf)
 330 {
 331         return 16384 - buf->read_remaining;
 332 }
 333
 334 void flush_buf(struct conn *rconn)
 335 {
 336         switch (rconn->targettype) {
 337         case TARGET_UNCONNECTED:
 338                 parse(rconn);
 339                 if (rconn->targettype != TARGET_UNCONNECTED)
 340                         flush_buf(rconn);
 341                 break;
 342         case TARGET_SOCK:
 343                 wake_up_interruptible(&(rconn->target.sock.wait));
 344                 break;
 345         case TARGET_OUT:
 346                 flush_out(rconn);
 347                 break;
 348         default:
 349                 BUG();
 350         }
 351 }
 352
 353 static int _receive_buf(struct conn *rconn, char *buf, int len, int userbuf)
 354 {
 355         struct data_buf_item *item = 0;
 356
 357         int totalcpy = 0;
 358
 359         BUG_ON(databuf_maypush(&(rconn->buf)) < len);
 360
 361         if (list_empty(&(rconn->buf.items)) == 0) {
 362                 struct list_head *last = rconn->buf.items.prev;
 363                 item = container_of(last, struct data_buf_item, buf_list);
 364
 365                 if (item->type != TYPE_BUF || rconn->buf.last_buflen <=
 366                                 item->data.buf.datalen)
 367                         item = 0;
 368         }
 369
 370         while (len > 0) {
 371                 int rc = 0;
 372                 int cpy = len;
 373                 if (item == 0) {
 374                         __u32 buflen = PAGESIZE;
 375                         if (buflen > 32768)
 376                                 buflen = 32768;
 377                         item = kmem_cache_alloc(data_buf_item_slab, GFP_KERNEL);
 378                         if (unlikely(item == 0)) {
 379                                 rc = -ENOMEM;
 380                                 goto error;
 381                         }
 382                         memset(item, 0, sizeof(item));
 383                         item->type = TYPE_BUF;
 384                         item->data.buf.buf = kmalloc(buflen, GFP_KERNEL);
 385
 386
 387                         if (unlikely(item->data.buf.buf == 0)) {
 388                                 kmem_cache_free(data_buf_item_slab, item);
 389                                 rc = -ENOMEM;
 390                                 goto error;
 391                         }
 392                         item->data.buf.datalen = 0;
 393                         list_add_tail(&(item->buf_list), &(rconn->buf.items));
 394                         rconn->buf.last_buflen = buflen;
 395                 }
 396
 397                 BUG_ON(item->type != TYPE_BUF);
 398                 BUG_ON(rconn->buf.last_buflen <= item->data.buf.datalen);
 399
 400                 if (rconn->buf.last_buflen - item->data.buf.datalen < cpy)
 401                         cpy = (rconn->buf.last_buflen - item->data.buf.datalen);
 402
 403                 if (userbuf) {
 404                         int notcopied = copy_from_user(item->data.buf.buf +
 405                                         item->data.buf.datalen, buf, cpy);
 406                         cpy -= notcopied;
 407                         if (unlikely(notcopied > 0))
 408                                 rc = -EFAULT;
 409                 } else {
 410                         memcpy(item->data.buf.buf + item->data.buf.datalen,
 411                                         buf, cpy);
 412                 }
 413
 414                 buf += cpy;
 415                 len -= cpy;
 416                 totalcpy += cpy;
 417
 418                 item->data.buf.datalen += cpy;
 419
 420 error:
 421                 if (unlikely(rc < 0)) {
 422                         if (totalcpy == 0)
 423                                 return rc;
 424                         break;
 425                 }
 426         }
 427
 428         rconn->buf.read_remaining += totalcpy;
 429
 430         return totalcpy;
 431 }
 432
 433 int receive_userbuf(struct conn *rconn, struct msghdr *msg)
 434 {
 435         int copied = 0;
 436         int iovidx = 0;
 437         int iovread = 0;
 438
 439         if (databuf_maypush(&(rconn->buf)) <= 0)
 440                 return -EAGAIN;
 441
 442         while (iovidx < msg->msg_iovlen) {
 443                 struct iovec *iov = msg->msg_iov + iovidx;
 444                 __user char *userbuf = iov->iov_base + iovread;
 445                 int len = iov->iov_len - iovread;
 446                 int rc;
 447                 int pushlimit;
 448
 449                 if (len == 0) {
 450                         iovidx++;
 451                         iovread = 0;
 452                         continue;
 453                 }
 454
 455                 pushlimit = databuf_maypush(&(rconn->buf));
 456
 457                 if (pushlimit <= 0) {
 458                         if (rconn->targettype == TARGET_UNCONNECTED)
 459                                 rc = -EPIPE;
 460                         else
 461                                 rc = -EAGAIN;
 462                 } else {
 463                         if (pushlimit < len)
 464                                 len = pushlimit;
 465
 466                         rc = _receive_buf(rconn, userbuf, len, 1);
 467                 }
 468
 469                 if (rc < 0) {
 470                         if (copied == 0)
 471                                 copied = rc;
 472                         break;
 473                 }
 474
 475                 copied += rc;
 476                 iovread += rc;
 477         }
 478
 479         if (copied > 0)
 480                 flush_buf(rconn);;
 481
 482         return copied;
 483 }
 484
 485 void receive_buf(struct conn *rconn, char *buf, int len)
 486 {
 487         BUG_ON(databuf_maypush(&(rconn->buf)) < len);
 488         _receive_buf(rconn, buf, len, 0);
 489         flush_buf(rconn);
 490 }
 491
 492 int receive_skb(struct conn *rconn, struct sk_buff *skb)
 493 {
 494         struct data_buf_item *item;
 495
 496         if (databuf_maypush(&(rconn->buf)) < skb->len)
 497                 return 1;
 498
 499         item = kmem_cache_alloc(data_buf_item_slab, GFP_KERNEL);
 500
 501         if (unlikely(item == 0))
 502                 return 1;
 503
 504         item->data.skb = skb;
 505         item->type = TYPE_SKB;
 506         list_add_tail(&(item->buf_list), &(rconn->buf.items));
 507         rconn->buf.read_remaining += skb->len;
 508         rconn->buf.last_buflen = 0;
 509
 510         flush_buf(rconn);
 511
 512         return 0;
 513 }
 514
 515 void wake_sender(struct conn *rconn)
 516 {
 517         switch (rconn->sourcetype) {
 518         case SOURCE_NONE:
 519                 /* nothing */
 520                 break;
 521         case SOURCE_SOCK:
 522                 wake_up_interruptible(&(rconn->source.sock.wait));
 523                 break;
 524         case SOURCE_IN:
 525                 drain_ooo_queue(rconn);
 526                 break;
 527         default:
 528                 BUG();
 529         }
 530 }
 531
 532 void forward_init(void)
 533 {
 534         data_buf_item_slab = kmem_cache_create("cor_data_buf_item",
 535                         sizeof(struct data_buf_item), 8, 0, 0);
 536 }