1/* 2 * net/sched/cls_tcindex.c Packet classifier for skb->tc_index 3 * 4 * Written 1998,1999 by Werner Almesberger, EPFL ICA 5 */ 6 7#include <linux/module.h> 8#include <linux/types.h> 9#include <linux/kernel.h> 10#include <linux/skbuff.h> 11#include <linux/errno.h> 12#include <linux/slab.h> 13#include <net/act_api.h> 14#include <net/netlink.h> 15#include <net/pkt_cls.h> 16 17/* 18 * Passing parameters to the root seems to be done more awkwardly than really 19 * necessary. At least, u32 doesn't seem to use such dirty hacks. To be 20 * verified. FIXME. 21 */ 22 23#define PERFECT_HASH_THRESHOLD 64 /* use perfect hash if not bigger */ 24#define DEFAULT_HASH_SIZE 64 /* optimized for diffserv */ 25 26 27#define PRIV(tp) ((struct tcindex_data *) (tp)->root) 28 29 30struct tcindex_filter_result { 31 struct tcf_exts exts; 32 struct tcf_result res; 33}; 34 35struct tcindex_filter { 36 u16 key; 37 struct tcindex_filter_result result; 38 struct tcindex_filter *next; 39}; 40 41 42struct tcindex_data { 43 struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */ 44 struct tcindex_filter **h; /* imperfect hash; only used if !perfect; 45 NULL if unused */ 46 u16 mask; /* AND key with mask */ 47 int shift; /* shift ANDed key to the right */ 48 int hash; /* hash table size; 0 if undefined */ 49 int alloc_hash; /* allocated size */ 50 int fall_through; /* 0: only classify if explicit match */ 51}; 52 53static const struct tcf_ext_map tcindex_ext_map = { 54 .police = TCA_TCINDEX_POLICE, 55 .action = TCA_TCINDEX_ACT 56}; 57 58static inline int 59tcindex_filter_is_set(struct tcindex_filter_result *r) 60{ 61 return tcf_exts_is_predicative(&r->exts) || r->res.classid; 62} 63 64static struct tcindex_filter_result * 65tcindex_lookup(struct tcindex_data *p, u16 key) 66{ 67 struct tcindex_filter *f; 68 69 if (p->perfect) 70 return tcindex_filter_is_set(p->perfect + key) ? 71 p->perfect + key : NULL; 72 else if (p->h) { 73 for (f = p->h[key % p->hash]; f; f = f->next) 74 if (f->key == key) 75 return &f->result; 76 } 77 78 return NULL; 79} 80 81 82static int tcindex_classify(struct sk_buff *skb, const struct tcf_proto *tp, 83 struct tcf_result *res) 84{ 85 struct tcindex_data *p = PRIV(tp); 86 struct tcindex_filter_result *f; 87 int key = (skb->tc_index & p->mask) >> p->shift; 88 89 pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n", 90 skb, tp, res, p); 91 92 f = tcindex_lookup(p, key); 93 if (!f) { 94 if (!p->fall_through) 95 return -1; 96 res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key); 97 res->class = 0; 98 pr_debug("alg 0x%x\n", res->classid); 99 return 0; 100 } 101 *res = f->res; 102 pr_debug("map 0x%x\n", res->classid); 103 104 return tcf_exts_exec(skb, &f->exts, res); 105} 106 107 108static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle) 109{ 110 struct tcindex_data *p = PRIV(tp); 111 struct tcindex_filter_result *r; 112 113 pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle); 114 if (p->perfect && handle >= p->alloc_hash) 115 return 0; 116 r = tcindex_lookup(p, handle); 117 return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL; 118} 119 120 121static void tcindex_put(struct tcf_proto *tp, unsigned long f) 122{ 123 pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f); 124} 125 126 127static int tcindex_init(struct tcf_proto *tp) 128{ 129 struct tcindex_data *p; 130 131 pr_debug("tcindex_init(tp %p)\n", tp); 132 p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL); 133 if (!p) 134 return -ENOMEM; 135 136 p->mask = 0xffff; 137 p->hash = DEFAULT_HASH_SIZE; 138 p->fall_through = 1; 139 140 tp->root = p; 141 return 0; 142} 143 144 145static int 146__tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock) 147{ 148 struct tcindex_data *p = PRIV(tp); 149 struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg; 150 struct tcindex_filter *f = NULL; 151 152 pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f); 153 if (p->perfect) { 154 if (!r->res.class) 155 return -ENOENT; 156 } else { 157 int i; 158 struct tcindex_filter **walk = NULL; 159 160 for (i = 0; i < p->hash; i++) 161 for (walk = p->h+i; *walk; walk = &(*walk)->next) 162 if (&(*walk)->result == r) 163 goto found; 164 return -ENOENT; 165 166found: 167 f = *walk; 168 if (lock) 169 tcf_tree_lock(tp); 170 *walk = f->next; 171 if (lock) 172 tcf_tree_unlock(tp); 173 } 174 tcf_unbind_filter(tp, &r->res); 175 tcf_exts_destroy(tp, &r->exts); 176 kfree(f); 177 return 0; 178} 179 180static int tcindex_delete(struct tcf_proto *tp, unsigned long arg) 181{ 182 return __tcindex_delete(tp, arg, 1); 183} 184 185static inline int 186valid_perfect_hash(struct tcindex_data *p) 187{ 188 return p->hash > (p->mask >> p->shift); 189} 190 191static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = { 192 [TCA_TCINDEX_HASH] = { .type = NLA_U32 }, 193 [TCA_TCINDEX_MASK] = { .type = NLA_U16 }, 194 [TCA_TCINDEX_SHIFT] = { .type = NLA_U32 }, 195 [TCA_TCINDEX_FALL_THROUGH] = { .type = NLA_U32 }, 196 [TCA_TCINDEX_CLASSID] = { .type = NLA_U32 }, 197}; 198 199static int 200tcindex_set_parms(struct net *net, struct tcf_proto *tp, unsigned long base, 201 u32 handle, struct tcindex_data *p, 202 struct tcindex_filter_result *r, struct nlattr **tb, 203 struct nlattr *est) 204{ 205 int err, balloc = 0; 206 struct tcindex_filter_result new_filter_result, *old_r = r; 207 struct tcindex_filter_result cr; 208 struct tcindex_data cp; 209 struct tcindex_filter *f = NULL; /* make gcc behave */ 210 struct tcf_exts e; 211 212 err = tcf_exts_validate(net, tp, tb, est, &e, &tcindex_ext_map); 213 if (err < 0) 214 return err; 215 216 memcpy(&cp, p, sizeof(cp)); 217 memset(&new_filter_result, 0, sizeof(new_filter_result)); 218 219 if (old_r) 220 memcpy(&cr, r, sizeof(cr)); 221 else 222 memset(&cr, 0, sizeof(cr)); 223 224 if (tb[TCA_TCINDEX_HASH]) 225 cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]); 226 227 if (tb[TCA_TCINDEX_MASK]) 228 cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]); 229 230 if (tb[TCA_TCINDEX_SHIFT]) 231 cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]); 232 233 err = -EBUSY; 234 /* Hash already allocated, make sure that we still meet the 235 * requirements for the allocated hash. 236 */ 237 if (cp.perfect) { 238 if (!valid_perfect_hash(&cp) || 239 cp.hash > cp.alloc_hash) 240 goto errout; 241 } else if (cp.h && cp.hash != cp.alloc_hash) 242 goto errout; 243 244 err = -EINVAL; 245 if (tb[TCA_TCINDEX_FALL_THROUGH]) 246 cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]); 247 248 if (!cp.hash) { 249 /* Hash not specified, use perfect hash if the upper limit 250 * of the hashing index is below the threshold. 251 */ 252 if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD) 253 cp.hash = (cp.mask >> cp.shift) + 1; 254 else 255 cp.hash = DEFAULT_HASH_SIZE; 256 } 257 258 if (!cp.perfect && !cp.h) 259 cp.alloc_hash = cp.hash; 260 261 /* Note: this could be as restrictive as if (handle & ~(mask >> shift)) 262 * but then, we'd fail handles that may become valid after some future 263 * mask change. While this is extremely unlikely to ever matter, 264 * the check below is safer (and also more backwards-compatible). 265 */ 266 if (cp.perfect || valid_perfect_hash(&cp)) 267 if (handle >= cp.alloc_hash) 268 goto errout; 269 270 271 err = -ENOMEM; 272 if (!cp.perfect && !cp.h) { 273 if (valid_perfect_hash(&cp)) { 274 cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL); 275 if (!cp.perfect) 276 goto errout; 277 balloc = 1; 278 } else { 279 cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL); 280 if (!cp.h) 281 goto errout; 282 balloc = 2; 283 } 284 } 285 286 if (cp.perfect) 287 r = cp.perfect + handle; 288 else 289 r = tcindex_lookup(&cp, handle) ? : &new_filter_result; 290 291 if (r == &new_filter_result) { 292 f = kzalloc(sizeof(*f), GFP_KERNEL); 293 if (!f) 294 goto errout_alloc; 295 } 296 297 if (tb[TCA_TCINDEX_CLASSID]) { 298 cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]); 299 tcf_bind_filter(tp, &cr.res, base); 300 } 301 302 tcf_exts_change(tp, &cr.exts, &e); 303 304 tcf_tree_lock(tp); 305 if (old_r && old_r != r) 306 memset(old_r, 0, sizeof(*old_r)); 307 308 memcpy(p, &cp, sizeof(cp)); 309 memcpy(r, &cr, sizeof(cr)); 310 311 if (r == &new_filter_result) { 312 struct tcindex_filter **fp; 313 314 f->key = handle; 315 f->result = new_filter_result; 316 f->next = NULL; 317 for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next) 318 /* nothing */; 319 *fp = f; 320 } 321 tcf_tree_unlock(tp); 322 323 return 0; 324 325errout_alloc: 326 if (balloc == 1) 327 kfree(cp.perfect); 328 else if (balloc == 2) 329 kfree(cp.h); 330errout: 331 tcf_exts_destroy(tp, &e); 332 return err; 333} 334 335static int 336tcindex_change(struct net *net, struct sk_buff *in_skb, 337 struct tcf_proto *tp, unsigned long base, u32 handle, 338 struct nlattr **tca, unsigned long *arg) 339{ 340 struct nlattr *opt = tca[TCA_OPTIONS]; 341 struct nlattr *tb[TCA_TCINDEX_MAX + 1]; 342 struct tcindex_data *p = PRIV(tp); 343 struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg; 344 int err; 345 346 pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p," 347 "p %p,r %p,*arg 0x%lx\n", 348 tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L); 349 350 if (!opt) 351 return 0; 352 353 err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy); 354 if (err < 0) 355 return err; 356 357 return tcindex_set_parms(net, tp, base, handle, p, r, tb, 358 tca[TCA_RATE]); 359} 360 361 362static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker) 363{ 364 struct tcindex_data *p = PRIV(tp); 365 struct tcindex_filter *f, *next; 366 int i; 367 368 pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p); 369 if (p->perfect) { 370 for (i = 0; i < p->hash; i++) { 371 if (!p->perfect[i].res.class) 372 continue; 373 if (walker->count >= walker->skip) { 374 if (walker->fn(tp, 375 (unsigned long) (p->perfect+i), walker) 376 < 0) { 377 walker->stop = 1; 378 return; 379 } 380 } 381 walker->count++; 382 } 383 } 384 if (!p->h) 385 return; 386 for (i = 0; i < p->hash; i++) { 387 for (f = p->h[i]; f; f = next) { 388 next = f->next; 389 if (walker->count >= walker->skip) { 390 if (walker->fn(tp, (unsigned long) &f->result, 391 walker) < 0) { 392 walker->stop = 1; 393 return; 394 } 395 } 396 walker->count++; 397 } 398 } 399} 400 401 402static int tcindex_destroy_element(struct tcf_proto *tp, 403 unsigned long arg, struct tcf_walker *walker) 404{ 405 return __tcindex_delete(tp, arg, 0); 406} 407 408 409static void tcindex_destroy(struct tcf_proto *tp) 410{ 411 struct tcindex_data *p = PRIV(tp); 412 struct tcf_walker walker; 413 414 pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p); 415 walker.count = 0; 416 walker.skip = 0; 417 walker.fn = &tcindex_destroy_element; 418 tcindex_walk(tp, &walker); 419 kfree(p->perfect); 420 kfree(p->h); 421 kfree(p); 422 tp->root = NULL; 423} 424 425 426static int tcindex_dump(struct tcf_proto *tp, unsigned long fh, 427 struct sk_buff *skb, struct tcmsg *t) 428{ 429 struct tcindex_data *p = PRIV(tp); 430 struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh; 431 unsigned char *b = skb_tail_pointer(skb); 432 struct nlattr *nest; 433 434 pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n", 435 tp, fh, skb, t, p, r, b); 436 pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h); 437 438 nest = nla_nest_start(skb, TCA_OPTIONS); 439 if (nest == NULL) 440 goto nla_put_failure; 441 442 if (!fh) { 443 t->tcm_handle = ~0; /* whatever ... */ 444 if (nla_put_u32(skb, TCA_TCINDEX_HASH, p->hash) || 445 nla_put_u16(skb, TCA_TCINDEX_MASK, p->mask) || 446 nla_put_u32(skb, TCA_TCINDEX_SHIFT, p->shift) || 447 nla_put_u32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through)) 448 goto nla_put_failure; 449 nla_nest_end(skb, nest); 450 } else { 451 if (p->perfect) { 452 t->tcm_handle = r-p->perfect; 453 } else { 454 struct tcindex_filter *f; 455 int i; 456 457 t->tcm_handle = 0; 458 for (i = 0; !t->tcm_handle && i < p->hash; i++) { 459 for (f = p->h[i]; !t->tcm_handle && f; 460 f = f->next) { 461 if (&f->result == r) 462 t->tcm_handle = f->key; 463 } 464 } 465 } 466 pr_debug("handle = %d\n", t->tcm_handle); 467 if (r->res.class && 468 nla_put_u32(skb, TCA_TCINDEX_CLASSID, r->res.classid)) 469 goto nla_put_failure; 470 471 if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0) 472 goto nla_put_failure; 473 nla_nest_end(skb, nest); 474 475 if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0) 476 goto nla_put_failure; 477 } 478 479 return skb->len; 480 481nla_put_failure: 482 nlmsg_trim(skb, b); 483 return -1; 484} 485 486static struct tcf_proto_ops cls_tcindex_ops __read_mostly = { 487 .kind = "tcindex", 488 .classify = tcindex_classify, 489 .init = tcindex_init, 490 .destroy = tcindex_destroy, 491 .get = tcindex_get, 492 .put = tcindex_put, 493 .change = tcindex_change, 494 .delete = tcindex_delete, 495 .walk = tcindex_walk, 496 .dump = tcindex_dump, 497 .owner = THIS_MODULE, 498}; 499 500static int __init init_tcindex(void) 501{ 502 return register_tcf_proto_ops(&cls_tcindex_ops); 503} 504 505static void __exit exit_tcindex(void) 506{ 507 unregister_tcf_proto_ops(&cls_tcindex_ops); 508} 509 510module_init(init_tcindex) 511module_exit(exit_tcindex) 512MODULE_LICENSE("GPL"); 513