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 databuf_free(struct data_buf *data)
  51 {
  52         while (!list_empty(&(data->items))) {
  53                 struct data_buf_item *item = container_of(data->items.next,
  54                                 struct data_buf_item, buf_list);
  55                 databuf_item_free(item);
  56         }
  57 }
  58
  59 static void databuf_nextreadchunk(struct data_buf *data)
  60 {
  61         if (data->lastread == 0) {
  62                 BUG_ON(data->last_read_offset != 0);
  63                 BUG_ON(list_empty(&(data->items)));
  64                 data->lastread = container_of(data->items.next,
  65                                 struct data_buf_item, buf_list);
  66         } else if (&(data->lastread->buf_list) != data->items.prev) {
  67                 data->lastread = container_of(data->lastread->buf_list.next,
  68                                 struct data_buf_item, buf_list);
  69
  70                 data->last_read_offset = 0;
  71         }
  72 }
  73
  74 int _databuf_pull(struct data_buf *data, char *dst, int len, int userbuf)
  75 {
  76         int totalcpy = 0;
  77
  78         BUG_ON(data->read_remaining < len);
  79
  80         if (data->lastread == 0)
  81                 databuf_nextreadchunk(data);
  82
  83         while(len > 0) {
  84                 int rc = 0;
  85                 int cpy = len;
  86
  87                 char *srcbuf = 0;
  88                 int srcbuflen = 0;
  89
  90                 char *srcbufcpystart = 0;
  91                 int srcbufcpylen = 0;
  92
  93                 BUG_ON(data->lastread == 0);
  94
  95                 if (data->lastread->type == TYPE_BUF) {
  96                         srcbuf = data->lastread->data.buf.buf;
  97                         srcbuflen = data->lastread->data.buf.datalen;
  98                 } else if (data->lastread->type == TYPE_SKB) {
  99                         srcbuf = data->lastread->data.skb->data;
 100                         srcbuflen = data->lastread->data.skb->len;
 101                 } else {
 102                         BUG();
 103                 }
 104
 105                 srcbufcpystart = srcbuf + data->last_read_offset;
 106                 srcbufcpylen = srcbuflen - data->last_read_offset;
 107
 108                 if (cpy > srcbufcpylen)
 109                         cpy = srcbufcpylen;
 110
 111                 if (userbuf) {
 112                         int notcopied = copy_to_user(dst, srcbufcpystart, cpy);
 113                         cpy -= notcopied;
 114                         if (notcopied > 0)
 115                                 rc = -EFAULT;
 116                 } else {
 117                         memcpy(dst, srcbufcpystart, cpy);
 118                 }
 119
 120                 dst += cpy;
 121                 len -= cpy;
 122                 totalcpy += cpy;
 123
 124                 data->read_remaining -= cpy;
 125                 data->last_read_offset += cpy;
 126
 127                 if (cpy == srcbufcpylen)
 128                         databuf_nextreadchunk(data);
 129
 130                 if (rc < 0) {
 131                         if (totalcpy == 0)
 132                                 totalcpy = rc;
 133                         break;
 134                 }
 135         }
 136
 137         return totalcpy;
 138 }
 139
 140 void databuf_pull(struct data_buf *data, char *dst, int len)
 141 {
 142         _databuf_pull(data, dst, len, 0);
 143 }
 144
 145 size_t databuf_pulluser(struct conn *sconn, struct msghdr *msg)
 146 {
 147         size_t copied = 0;
 148         int iovidx = 0;
 149         int iovread = 0;
 150
 151         while (iovidx < msg->msg_iovlen) {
 152                 int rc;
 153
 154                 struct iovec *iov = msg->msg_iov + iovidx;
 155                 __user char *msg = iov->iov_base + iovread;
 156                 unsigned int len = iov->iov_len - iovread;
 157
 158                 if (len == 0) {
 159                         iovidx++;
 160                         iovread = 0;
 161                         continue;
 162                 }
 163
 164                 if (sconn->buf.read_remaining == 0) {
 165                         if (sconn->sourcetype == SOURCE_NONE)
 166                                 rc = -EPIPE;
 167                         else
 168                                 rc = -EAGAIN;
 169                 } else {
 170                         if (len > sconn->buf.read_remaining)
 171                                 len = sconn->buf.read_remaining;
 172
 173                         rc = _databuf_pull(&(sconn->buf), msg, len, 1);
 174                 }
 175
 176                 BUG_ON(rc == 0);
 177
 178                 if (rc < 0) {
 179                         if (copied == 0)
 180                                 copied = rc;
 181                         break;
 182                 }
 183
 184                 copied += rc;
 185                 iovread += rc;
 186         }
 187
 188         return copied;
 189 }
 190
 191 /* ack up to *not* including pos (e.g. pos=0 ack nothing) */
 192 void databuf_ack(struct data_buf *buf, __u64 pos)
 193 {
 194         if (pos <= buf->first_offset)
 195                 return;
 196         BUG_ON(pos > buf->read_offset);
 197
 198         while (1) {
 199                 struct list_head *first = buf->items.next;
 200                 struct data_buf_item *firstitem = container_of(first,
 201                                 struct data_buf_item, buf_list);
 202                 int firstlen = 0;
 203
 204                 BUG_ON(list_empty(&(buf->items)));
 205
 206                 if (firstitem->type == TYPE_BUF) {
 207                         firstlen = firstitem->data.buf.datalen;
 208                 } else if (firstitem->type == TYPE_SKB) {
 209                         firstlen = firstitem->data.skb->len;
 210                 } else {
 211                         BUG();
 212                 }
 213
 214                 if (buf->first_offset + firstlen > pos ||
 215                                 firstitem == buf->lastread)
 216                         break;
 217
 218                 buf->first_offset += firstlen;
 219
 220                 databuf_item_free(firstitem);
 221         }
 222 }
 223
 224 void databuf_ackread(struct data_buf *buf)
 225 {
 226         databuf_ack(buf, buf->read_offset);
 227 }
 228
 229 int databuf_maypush(struct data_buf *buf)
 230 {
 231         return 16384 - buf->read_remaining;
 232 }
 233
 234 static void local_delivery(struct conn *rconn)
 235 {
 236         wake_up_interruptible(&(rconn->target.sock.wait));
 237 }
 238
 239 void flush_buf(struct conn *rconn)
 240 {
 241         switch (rconn->targettype) {
 242         case TARGET_UNCONNECTED:
 243                 parse(rconn);
 244                 if (rconn->targettype != TARGET_UNCONNECTED)
 245                         flush_buf(rconn);
 246                 break;
 247         case TARGET_SOCK:
 248                 local_delivery(rconn);
 249                 break;
 250         case TARGET_OUT:
 251                 flush_out(rconn);
 252                 break;
 253         default:
 254                 BUG();
 255         }
 256 }
 257
 258 static int _receive_buf(struct conn *rconn, char *buf, int len, int userbuf)
 259 {
 260         struct data_buf_item *item = 0;
 261
 262         int totalcpy = 0;
 263
 264         BUG_ON(databuf_maypush(&(rconn->buf)) < len);
 265
 266         if (list_empty(&(rconn->buf.items)) == 0) {
 267                 struct list_head *last = rconn->buf.items.prev;
 268                 item = container_of(last, struct data_buf_item, buf_list);
 269
 270                 if (item->type != TYPE_BUF || rconn->buf.last_buflen <=
 271                                 item->data.buf.datalen)
 272                         item = 0;
 273         }
 274
 275         while (len > 0) {
 276                 int rc = 0;
 277                 int cpy = len;
 278                 if (item == 0) {
 279                         item = kmem_cache_alloc(data_buf_item_slab, GFP_KERNEL);
 280                         if (item == 0) {
 281                                 rc = -ENOMEM;
 282                                 goto error;
 283                         }
 284                         memset(item, 0, sizeof(item));
 285                         item->type = TYPE_BUF;
 286                         item->data.buf.buf = kmalloc(PAGESIZE, GFP_KERNEL);
 287                         if (item->data.buf.buf == 0) {
 288                                 kmem_cache_free(data_buf_item_slab, item);
 289                                 rc = -ENOMEM;
 290                                 goto error;
 291                         }
 292                         item->data.buf.datalen = 0;
 293                         list_add_tail(&(item->buf_list), &(rconn->buf.items));
 294                         rconn->buf.last_buflen = PAGESIZE;
 295                 }
 296
 297                 BUG_ON(item->type != TYPE_BUF);
 298                 BUG_ON(rconn->buf.last_buflen <= item->data.buf.datalen);
 299
 300                 if (rconn->buf.last_buflen - item->data.buf.datalen < cpy)
 301                         cpy = (rconn->buf.last_buflen - item->data.buf.datalen);
 302
 303                 if (userbuf) {
 304                         int notcopied = copy_from_user(item->data.buf.buf +
 305                                         item->data.buf.datalen, buf, cpy);
 306                         cpy -= notcopied;
 307                         if (notcopied > 0)
 308                                 rc = -EFAULT;
 309                 } else {
 310                         memcpy(item->data.buf.buf + item->data.buf.datalen,
 311                                         buf, cpy);
 312                 }
 313
 314                 buf += cpy;
 315                 len -= cpy;
 316                 totalcpy += cpy;
 317
 318                 item->data.buf.datalen += cpy;
 319
 320 error:
 321                 if (rc < 0) {
 322                         if (totalcpy == 0)
 323                                 return rc;
 324                         break;
 325                 }
 326         }
 327
 328         rconn->buf.read_remaining += totalcpy;
 329
 330         return totalcpy;
 331 }
 332
 333 int receive_userbuf(struct conn *rconn, struct msghdr *msg)
 334 {
 335         int copied = 0;
 336         int iovidx = 0;
 337         int iovread = 0;
 338
 339         if (databuf_maypush(&(rconn->buf)) <= 0)
 340                 return -EAGAIN;
 341
 342         while (iovidx < msg->msg_iovlen) {
 343                 struct iovec *iov = msg->msg_iov + iovidx;
 344                 __user char *userbuf = iov->iov_base + iovread;
 345                 int len = iov->iov_len - iovread;
 346                 int rc;
 347                 int pushlimit;
 348
 349                 if (len == 0) {
 350                         iovidx++;
 351                         iovread = 0;
 352                         continue;
 353                 }
 354
 355                 pushlimit = databuf_maypush(&(rconn->buf));
 356
 357                 if (pushlimit <= 0) {
 358                         if (rconn->targettype == TARGET_UNCONNECTED)
 359                                 rc = -EPIPE;
 360                         else
 361                                 rc = -EAGAIN;
 362                 } else {
 363                         if (pushlimit < len)
 364                                 len = pushlimit;
 365
 366                         rc = _receive_buf(rconn, userbuf, len, 1);
 367                 }
 368
 369                 if (rc < 0) {
 370                         if (copied == 0)
 371                                 copied = rc;
 372                         break;
 373                 }
 374
 375                 copied += rc;
 376                 iovread += rc;
 377         }
 378
 379         if (copied > 0)
 380                 flush_buf(rconn);;
 381
 382         return copied;
 383 }
 384
 385 void receive_buf(struct conn *rconn, char *buf, int len)
 386 {
 387         BUG_ON(databuf_maypush(&(rconn->buf)) < len);
 388         _receive_buf(rconn, buf, len, 0);
 389         flush_buf(rconn);
 390 }
 391
 392 int receive_skb(struct conn *rconn, struct sk_buff *skb)
 393 {
 394         struct data_buf_item *item;
 395
 396         if (databuf_maypush(&(rconn->buf)) < skb->len)
 397                 return 1;
 398
 399         item = kmem_cache_alloc(data_buf_item_slab, GFP_KERNEL);
 400
 401         if (item == 0)
 402                 return 1;
 403
 404         item->data.skb = skb;
 405         item->type = TYPE_SKB;
 406         list_add_tail(&(item->buf_list), &(rconn->buf.items));
 407         rconn->buf.read_remaining += skb->len;
 408         rconn->buf.last_buflen = 0;
 409
 410         flush_buf(rconn);
 411
 412         return 0;
 413 }
 414
 415 void wake_sender(struct conn *rconn)
 416 {
 417         switch (rconn->sourcetype) {
 418         case SOURCE_NONE:
 419                 /* nothing */
 420                 break;
 421         case SOURCE_SOCK:
 422                 wake_up_interruptible(&(rconn->source.sock.wait));
 423                 break;
 424         case SOURCE_IN:
 425                 drain_ooo_queue(rconn);
 426                 break;
 427         default:
 428                 BUG();
 429         }
 430 }
 431
 432 void forward_init(void)
 433 {
 434         data_buf_item_slab = kmem_cache_create("cor_data_buf_item",
 435                         sizeof(struct data_buf_item), 8, 0, 0);
 436 }