net/caif/cfpkt_skbuff.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Author:      Sjur Brendeland/sjur.brandeland@stericsson.com
   4  * License terms: GNU General Public License (GPL) version 2
   5  */
   6
   7 #include <linux/string.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/hardirq.h>
  10 #include <net/caif/cfpkt.h>
  11
  12 #define PKT_PREFIX CAIF_NEEDED_HEADROOM
  13 #define PKT_POSTFIX CAIF_NEEDED_TAILROOM
  14 #define PKT_LEN_WHEN_EXTENDING 128
  15 #define PKT_ERROR(pkt, errmsg) do {        \
  16     cfpkt_priv(pkt)->erronous = true;      \
  17     skb_reset_tail_pointer(&pkt->skb);     \
  18     pr_warning("CAIF: " errmsg);\
  19   } while (0)
  20
  21 struct cfpktq {
  22         struct sk_buff_head head;
  23         atomic_t count;
  24         /* Lock protects count updates */
  25         spinlock_t lock;
  26 };
  27
  28 /*
  29  * net/caif/ is generic and does not
  30  * understand SKB, so we do this typecast
  31  */
  32 struct cfpkt {
  33         struct sk_buff skb;
  34 };
  35
  36 /* Private data inside SKB */
  37 struct cfpkt_priv_data {
  38         struct dev_info dev_info;
  39         bool erronous;
  40 };
  41
  42 inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
  43 {
  44         return (struct cfpkt_priv_data *) pkt->skb.cb;
  45 }
  46
  47 inline bool is_erronous(struct cfpkt *pkt)
  48 {
  49         return cfpkt_priv(pkt)->erronous;
  50 }
  51
  52 inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
  53 {
  54         return &pkt->skb;
  55 }
  56
  57 inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
  58 {
  59         return (struct cfpkt *) skb;
  60 }
  61
  62
  63 struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
  64 {
  65         struct cfpkt *pkt = skb_to_pkt(nativepkt);
  66         cfpkt_priv(pkt)->erronous = false;
  67         return pkt;
  68 }
  69 EXPORT_SYMBOL(cfpkt_fromnative);
  70
  71 void *cfpkt_tonative(struct cfpkt *pkt)
  72 {
  73         return (void *) pkt;
  74 }
  75 EXPORT_SYMBOL(cfpkt_tonative);
  76
  77 static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
  78 {
  79         struct sk_buff *skb;
  80
  81         if (likely(in_interrupt()))
  82                 skb = alloc_skb(len + pfx, GFP_ATOMIC);
  83         else
  84                 skb = alloc_skb(len + pfx, GFP_KERNEL);
  85
  86         if (unlikely(skb == NULL))
  87                 return NULL;
  88
  89         skb_reserve(skb, pfx);
  90         return skb_to_pkt(skb);
  91 }
  92
  93 inline struct cfpkt *cfpkt_create(u16 len)
  94 {
  95         return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
  96 }
  97 EXPORT_SYMBOL(cfpkt_create);
  98
  99 void cfpkt_destroy(struct cfpkt *pkt)
 100 {
 101         struct sk_buff *skb = pkt_to_skb(pkt);
 102         kfree_skb(skb);
 103 }
 104 EXPORT_SYMBOL(cfpkt_destroy);
 105
 106 inline bool cfpkt_more(struct cfpkt *pkt)
 107 {
 108         struct sk_buff *skb = pkt_to_skb(pkt);
 109         return skb->len > 0;
 110 }
 111 EXPORT_SYMBOL(cfpkt_more);
 112
 113 int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
 114 {
 115         struct sk_buff *skb = pkt_to_skb(pkt);
 116         if (skb_headlen(skb) >= len) {
 117                 memcpy(data, skb->data, len);
 118                 return 0;
 119         }
 120         return !cfpkt_extr_head(pkt, data, len) &&
 121             !cfpkt_add_head(pkt, data, len);
 122 }
 123 EXPORT_SYMBOL(cfpkt_peek_head);
 124
 125 int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
 126 {
 127         struct sk_buff *skb = pkt_to_skb(pkt);
 128         u8 *from;
 129         if (unlikely(is_erronous(pkt)))
 130                 return -EPROTO;
 131
 132         if (unlikely(len > skb->len)) {
 133                 PKT_ERROR(pkt, "cfpkt_extr_head read beyond end of packet\n");
 134                 return -EPROTO;
 135         }
 136
 137         if (unlikely(len > skb_headlen(skb))) {
 138                 if (unlikely(skb_linearize(skb) != 0)) {
 139                         PKT_ERROR(pkt, "cfpkt_extr_head linearize failed\n");
 140                         return -EPROTO;
 141                 }
 142         }
 143         from = skb_pull(skb, len);
 144         from -= len;
 145         memcpy(data, from, len);
 146         return 0;
 147 }
 148 EXPORT_SYMBOL(cfpkt_extr_head);
 149
 150 int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
 151 {
 152         struct sk_buff *skb = pkt_to_skb(pkt);
 153         u8 *data = dta;
 154         u8 *from;
 155         if (unlikely(is_erronous(pkt)))
 156                 return -EPROTO;
 157
 158         if (unlikely(skb_linearize(skb) != 0)) {
 159                 PKT_ERROR(pkt, "cfpkt_extr_trail linearize failed\n");
 160                 return -EPROTO;
 161         }
 162         if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
 163                 PKT_ERROR(pkt, "cfpkt_extr_trail read beyond end of packet\n");
 164                 return -EPROTO;
 165         }
 166         from = skb_tail_pointer(skb) - len;
 167         skb_trim(skb, skb->len - len);
 168         memcpy(data, from, len);
 169         return 0;
 170 }
 171 EXPORT_SYMBOL(cfpkt_extr_trail);
 172
 173 int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
 174 {
 175         return cfpkt_add_body(pkt, NULL, len);
 176 }
 177 EXPORT_SYMBOL(cfpkt_pad_trail);
 178
 179 int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
 180 {
 181         struct sk_buff *skb = pkt_to_skb(pkt);
 182         struct sk_buff *lastskb;
 183         u8 *to;
 184         u16 addlen = 0;
 185
 186
 187         if (unlikely(is_erronous(pkt)))
 188                 return -EPROTO;
 189
 190         lastskb = skb;
 191
 192         /* Check whether we need to add space at the tail */
 193         if (unlikely(skb_tailroom(skb) < len)) {
 194                 if (likely(len < PKT_LEN_WHEN_EXTENDING))
 195                         addlen = PKT_LEN_WHEN_EXTENDING;
 196                 else
 197                         addlen = len;
 198         }
 199
 200         /* Check whether we need to change the SKB before writing to the tail */
 201         if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
 202
 203                 /* Make sure data is writable */
 204                 if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
 205                         PKT_ERROR(pkt, "cfpkt_add_body: cow failed\n");
 206                         return -EPROTO;
 207                 }
 208                 /*
 209                  * Is the SKB non-linear after skb_cow_data()? If so, we are
 210                  * going to add data to the last SKB, so we need to adjust
 211                  * lengths of the top SKB.
 212                  */
 213                 if (lastskb != skb) {
 214                         pr_warning("CAIF: %s(): Packet is non-linear\n",
 215                                    __func__);
 216                         skb->len += len;
 217                         skb->data_len += len;
 218                 }
 219         }
 220
 221         /* All set to put the last SKB and optionally write data there. */
 222         to = skb_put(lastskb, len);
 223         if (likely(data))
 224                 memcpy(to, data, len);
 225         return 0;
 226 }
 227 EXPORT_SYMBOL(cfpkt_add_body);
 228
 229 inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
 230 {
 231         return cfpkt_add_body(pkt, &data, 1);
 232 }
 233 EXPORT_SYMBOL(cfpkt_addbdy);
 234
 235 int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
 236 {
 237         struct sk_buff *skb = pkt_to_skb(pkt);
 238         struct sk_buff *lastskb;
 239         u8 *to;
 240         const u8 *data = data2;
 241         if (unlikely(is_erronous(pkt)))
 242                 return -EPROTO;
 243         if (unlikely(skb_headroom(skb) < len)) {
 244                 PKT_ERROR(pkt, "cfpkt_add_head: no headroom\n");
 245                 return -EPROTO;
 246         }
 247
 248         /* Make sure data is writable */
 249         if (unlikely(skb_cow_data(skb, 0, &lastskb) < 0)) {
 250                 PKT_ERROR(pkt, "cfpkt_add_head: cow failed\n");
 251                 return -EPROTO;
 252         }
 253
 254         to = skb_push(skb, len);
 255         memcpy(to, data, len);
 256         return 0;
 257 }
 258 EXPORT_SYMBOL(cfpkt_add_head);
 259
 260 inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
 261 {
 262         return cfpkt_add_body(pkt, data, len);
 263 }
 264 EXPORT_SYMBOL(cfpkt_add_trail);
 265
 266 inline u16 cfpkt_getlen(struct cfpkt *pkt)
 267 {
 268         struct sk_buff *skb = pkt_to_skb(pkt);
 269         return skb->len;
 270 }
 271 EXPORT_SYMBOL(cfpkt_getlen);
 272
 273 inline u16 cfpkt_iterate(struct cfpkt *pkt,
 274                             u16 (*iter_func)(u16, void *, u16),
 275                             u16 data)
 276 {
 277         /*
 278          * Don't care about the performance hit of linearizing,
 279          * Checksum should not be used on high-speed interfaces anyway.
 280          */
 281         if (unlikely(is_erronous(pkt)))
 282                 return -EPROTO;
 283         if (unlikely(skb_linearize(&pkt->skb) != 0)) {
 284                 PKT_ERROR(pkt, "cfpkt_iterate: linearize failed\n");
 285                 return -EPROTO;
 286         }
 287         return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
 288 }
 289 EXPORT_SYMBOL(cfpkt_iterate);
 290
 291 int cfpkt_setlen(struct cfpkt *pkt, u16 len)
 292 {
 293         struct sk_buff *skb = pkt_to_skb(pkt);
 294
 295
 296         if (unlikely(is_erronous(pkt)))
 297                 return -EPROTO;
 298
 299         if (likely(len <= skb->len)) {
 300                 if (unlikely(skb->data_len))
 301                         ___pskb_trim(skb, len);
 302                 else
 303                         skb_trim(skb, len);
 304
 305                         return cfpkt_getlen(pkt);
 306         }
 307
 308         /* Need to expand SKB */
 309         if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
 310                 PKT_ERROR(pkt, "cfpkt_setlen: skb_pad_trail failed\n");
 311
 312         return cfpkt_getlen(pkt);
 313 }
 314 EXPORT_SYMBOL(cfpkt_setlen);
 315
 316 struct cfpkt *cfpkt_create_uplink(const unsigned char *data, unsigned int len)
 317 {
 318         struct cfpkt *pkt = cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
 319         if (unlikely(data != NULL))
 320                 cfpkt_add_body(pkt, data, len);
 321         return pkt;
 322 }
 323 EXPORT_SYMBOL(cfpkt_create_uplink);
 324
 325 struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
 326                              struct cfpkt *addpkt,
 327                              u16 expectlen)
 328 {
 329         struct sk_buff *dst = pkt_to_skb(dstpkt);
 330         struct sk_buff *add = pkt_to_skb(addpkt);
 331         u16 addlen = skb_headlen(add);
 332         u16 neededtailspace;
 333         struct sk_buff *tmp;
 334         u16 dstlen;
 335         u16 createlen;
 336         if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
 337                 cfpkt_destroy(addpkt);
 338                 return dstpkt;
 339         }
 340         if (expectlen > addlen)
 341                 neededtailspace = expectlen;
 342         else
 343                 neededtailspace = addlen;
 344
 345         if (dst->tail + neededtailspace > dst->end) {
 346                 /* Create a dumplicate of 'dst' with more tail space */
 347                 dstlen = skb_headlen(dst);
 348                 createlen = dstlen + neededtailspace;
 349                 tmp = pkt_to_skb(
 350                         cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX));
 351                 if (!tmp)
 352                         return NULL;
 353                 skb_set_tail_pointer(tmp, dstlen);
 354                 tmp->len = dstlen;
 355                 memcpy(tmp->data, dst->data, dstlen);
 356                 cfpkt_destroy(dstpkt);
 357                 dst = tmp;
 358         }
 359         memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
 360         cfpkt_destroy(addpkt);
 361         dst->tail += addlen;
 362         dst->len += addlen;
 363         return skb_to_pkt(dst);
 364 }
 365 EXPORT_SYMBOL(cfpkt_append);
 366
 367 struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
 368 {
 369         struct sk_buff *skb2;
 370         struct sk_buff *skb = pkt_to_skb(pkt);
 371         u8 *split = skb->data + pos;
 372         u16 len2nd = skb_tail_pointer(skb) - split;
 373
 374         if (unlikely(is_erronous(pkt)))
 375                 return NULL;
 376
 377         if (skb->data + pos > skb_tail_pointer(skb)) {
 378                 PKT_ERROR(pkt,
 379                           "cfpkt_split: trying to split beyond end of packet");
 380                 return NULL;
 381         }
 382
 383         /* Create a new packet for the second part of the data */
 384         skb2 = pkt_to_skb(
 385                 cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
 386                                  PKT_PREFIX));
 387
 388         if (skb2 == NULL)
 389                 return NULL;
 390
 391         /* Reduce the length of the original packet */
 392         skb_set_tail_pointer(skb, pos);
 393         skb->len = pos;
 394
 395         memcpy(skb2->data, split, len2nd);
 396         skb2->tail += len2nd;
 397         skb2->len += len2nd;
 398         return skb_to_pkt(skb2);
 399 }
 400 EXPORT_SYMBOL(cfpkt_split);
 401
 402 char *cfpkt_log_pkt(struct cfpkt *pkt, char *buf, int buflen)
 403 {
 404         struct sk_buff *skb = pkt_to_skb(pkt);
 405         char *p = buf;
 406         int i;
 407
 408         /*
 409          * Sanity check buffer length, it needs to be at least as large as
 410          * the header info: ~=50+ bytes
 411          */
 412         if (buflen < 50)
 413                 return NULL;
 414
 415         snprintf(buf, buflen, "%s: pkt:%p len:%ld(%ld+%ld) {%ld,%ld} data: [",
 416                 is_erronous(pkt) ? "ERRONOUS-SKB" :
 417                  (skb->data_len != 0 ? "COMPLEX-SKB" : "SKB"),
 418                  skb,
 419                  (long) skb->len,
 420                  (long) (skb_tail_pointer(skb) - skb->data),
 421                  (long) skb->data_len,
 422                  (long) (skb->data - skb->head),
 423                  (long) (skb_tail_pointer(skb) - skb->head));
 424         p = buf + strlen(buf);
 425
 426         for (i = 0; i < skb_tail_pointer(skb) - skb->data && i < 300; i++) {
 427                 if (p > buf + buflen - 10) {
 428                         sprintf(p, "...");
 429                         p = buf + strlen(buf);
 430                         break;
 431                 }
 432                 sprintf(p, "%02x,", skb->data[i]);
 433                 p = buf + strlen(buf);
 434         }
 435         sprintf(p, "]\n");
 436         return buf;
 437 }
 438 EXPORT_SYMBOL(cfpkt_log_pkt);
 439
 440 int cfpkt_raw_append(struct cfpkt *pkt, void **buf, unsigned int buflen)
 441 {
 442         struct sk_buff *skb = pkt_to_skb(pkt);
 443         struct sk_buff *lastskb;
 444
 445         caif_assert(buf != NULL);
 446         if (unlikely(is_erronous(pkt)))
 447                 return -EPROTO;
 448         /* Make sure SKB is writable */
 449         if (unlikely(skb_cow_data(skb, 0, &lastskb) < 0)) {
 450                 PKT_ERROR(pkt, "cfpkt_raw_append: skb_cow_data failed\n");
 451                 return -EPROTO;
 452         }
 453
 454         if (unlikely(skb_linearize(skb) != 0)) {
 455                 PKT_ERROR(pkt, "cfpkt_raw_append: linearize failed\n");
 456                 return -EPROTO;
 457         }
 458
 459         if (unlikely(skb_tailroom(skb) < buflen)) {
 460                 PKT_ERROR(pkt, "cfpkt_raw_append: buffer too short - failed\n");
 461                 return -EPROTO;
 462         }
 463
 464         *buf = skb_put(skb, buflen);
 465         return 1;
 466 }
 467 EXPORT_SYMBOL(cfpkt_raw_append);
 468
 469 int cfpkt_raw_extract(struct cfpkt *pkt, void **buf, unsigned int buflen)
 470 {
 471         struct sk_buff *skb = pkt_to_skb(pkt);
 472
 473         caif_assert(buf != NULL);
 474         if (unlikely(is_erronous(pkt)))
 475                 return -EPROTO;
 476
 477         if (unlikely(buflen > skb->len)) {
 478                 PKT_ERROR(pkt, "cfpkt_raw_extract: buflen too large "
 479                                 "- failed\n");
 480                 return -EPROTO;
 481         }
 482
 483         if (unlikely(buflen > skb_headlen(skb))) {
 484                 if (unlikely(skb_linearize(skb) != 0)) {
 485                         PKT_ERROR(pkt, "cfpkt_raw_extract: linearize failed\n");
 486                         return -EPROTO;
 487                 }
 488         }
 489
 490         *buf = skb->data;
 491         skb_pull(skb, buflen);
 492
 493         return 1;
 494 }
 495 EXPORT_SYMBOL(cfpkt_raw_extract);
 496
 497 inline bool cfpkt_erroneous(struct cfpkt *pkt)
 498 {
 499         return cfpkt_priv(pkt)->erronous;
 500 }
 501 EXPORT_SYMBOL(cfpkt_erroneous);
 502
 503 struct cfpktq *cfpktq_create(void)
 504 {
 505         struct cfpktq *q = kmalloc(sizeof(struct cfpktq), GFP_ATOMIC);
 506         if (!q)
 507                 return NULL;
 508         skb_queue_head_init(&q->head);
 509         atomic_set(&q->count, 0);
 510         spin_lock_init(&q->lock);
 511         return q;
 512 }
 513 EXPORT_SYMBOL(cfpktq_create);
 514
 515 void cfpkt_queue(struct cfpktq *pktq, struct cfpkt *pkt, unsigned short prio)
 516 {
 517         atomic_inc(&pktq->count);
 518         spin_lock(&pktq->lock);
 519         skb_queue_tail(&pktq->head, pkt_to_skb(pkt));
 520         spin_unlock(&pktq->lock);
 521
 522 }
 523 EXPORT_SYMBOL(cfpkt_queue);
 524
 525 struct cfpkt *cfpkt_qpeek(struct cfpktq *pktq)
 526 {
 527         struct cfpkt *tmp;
 528         spin_lock(&pktq->lock);
 529         tmp = skb_to_pkt(skb_peek(&pktq->head));
 530         spin_unlock(&pktq->lock);
 531         return tmp;
 532 }
 533 EXPORT_SYMBOL(cfpkt_qpeek);
 534
 535 struct cfpkt *cfpkt_dequeue(struct cfpktq *pktq)
 536 {
 537         struct cfpkt *pkt;
 538         spin_lock(&pktq->lock);
 539         pkt = skb_to_pkt(skb_dequeue(&pktq->head));
 540         if (pkt) {
 541                 atomic_dec(&pktq->count);
 542                 caif_assert(atomic_read(&pktq->count) >= 0);
 543         }
 544         spin_unlock(&pktq->lock);
 545         return pkt;
 546 }
 547 EXPORT_SYMBOL(cfpkt_dequeue);
 548
 549 int cfpkt_qcount(struct cfpktq *pktq)
 550 {
 551         return atomic_read(&pktq->count);
 552 }
 553 EXPORT_SYMBOL(cfpkt_qcount);
 554
 555 struct cfpkt *cfpkt_clone_release(struct cfpkt *pkt)
 556 {
 557         struct cfpkt *clone;
 558         clone  = skb_to_pkt(skb_clone(pkt_to_skb(pkt), GFP_ATOMIC));
 559         /* Free original packet. */
 560         cfpkt_destroy(pkt);
 561         if (!clone)
 562                 return NULL;
 563         return clone;
 564 }
 565 EXPORT_SYMBOL(cfpkt_clone_release);
 566
 567 struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
 568 {
 569         return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
 570 }
 571 EXPORT_SYMBOL(cfpkt_info);