1/* 2 * net/sched/police.c Input police filter. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 7 * 2 of the License, or (at your option) any later version. 8 * 9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> 10 * J Hadi Salim (action changes) 11 */ 12 13#include <linux/module.h> 14#include <linux/types.h> 15#include <linux/kernel.h> 16#include <linux/string.h> 17#include <linux/errno.h> 18#include <linux/skbuff.h> 19#include <linux/rtnetlink.h> 20#include <linux/init.h> 21#include <linux/slab.h> 22#include <net/act_api.h> 23#include <net/netlink.h> 24 25#define L2T(p,L) qdisc_l2t((p)->tcfp_R_tab, L) 26#define L2T_P(p,L) qdisc_l2t((p)->tcfp_P_tab, L) 27 28#define POL_TAB_MASK 15 29static struct tcf_common *tcf_police_ht[POL_TAB_MASK + 1]; 30static u32 police_idx_gen; 31static DEFINE_RWLOCK(police_lock); 32 33static struct tcf_hashinfo police_hash_info = { 34 .htab = tcf_police_ht, 35 .hmask = POL_TAB_MASK, 36 .lock = &police_lock, 37}; 38 39/* old policer structure from before tc actions */ 40struct tc_police_compat 41{ 42 u32 index; 43 int action; 44 u32 limit; 45 u32 burst; 46 u32 mtu; 47 struct tc_ratespec rate; 48 struct tc_ratespec peakrate; 49}; 50 51/* Each policer is serialized by its individual spinlock */ 52 53static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb, 54 int type, struct tc_action *a) 55{ 56 struct tcf_common *p; 57 int err = 0, index = -1, i = 0, s_i = 0, n_i = 0; 58 struct nlattr *nest; 59 60 read_lock_bh(&police_lock); 61 62 s_i = cb->args[0]; 63 64 for (i = 0; i < (POL_TAB_MASK + 1); i++) { 65 p = tcf_police_ht[tcf_hash(i, POL_TAB_MASK)]; 66 67 for (; p; p = p->tcfc_next) { 68 index++; 69 if (index < s_i) 70 continue; 71 a->priv = p; 72 a->order = index; 73 nest = nla_nest_start(skb, a->order); 74 if (nest == NULL) 75 goto nla_put_failure; 76 if (type == RTM_DELACTION) 77 err = tcf_action_dump_1(skb, a, 0, 1); 78 else 79 err = tcf_action_dump_1(skb, a, 0, 0); 80 if (err < 0) { 81 index--; 82 nla_nest_cancel(skb, nest); 83 goto done; 84 } 85 nla_nest_end(skb, nest); 86 n_i++; 87 } 88 } 89done: 90 read_unlock_bh(&police_lock); 91 if (n_i) 92 cb->args[0] += n_i; 93 return n_i; 94 95nla_put_failure: 96 nla_nest_cancel(skb, nest); 97 goto done; 98} 99 100static void tcf_police_free_rcu(struct rcu_head *head) 101{ 102 kfree(container_of(head, struct tcf_police, tcf_rcu)); 103} 104 105static void tcf_police_destroy(struct tcf_police *p) 106{ 107 unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK); 108 struct tcf_common **p1p; 109 110 for (p1p = &tcf_police_ht[h]; *p1p; p1p = &(*p1p)->tcfc_next) { 111 if (*p1p == &p->common) { 112 write_lock_bh(&police_lock); 113 *p1p = p->tcf_next; 114 write_unlock_bh(&police_lock); 115 gen_kill_estimator(&p->tcf_bstats, 116 &p->tcf_rate_est); 117 if (p->tcfp_R_tab) 118 qdisc_put_rtab(p->tcfp_R_tab); 119 if (p->tcfp_P_tab) 120 qdisc_put_rtab(p->tcfp_P_tab); 121 /* 122 * gen_estimator est_timer() might access p->tcf_lock 123 * or bstats, wait a RCU grace period before freeing p 124 */ 125 call_rcu(&p->tcf_rcu, tcf_police_free_rcu); 126 return; 127 } 128 } 129 WARN_ON(1); 130} 131 132static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = { 133 [TCA_POLICE_RATE] = { .len = TC_RTAB_SIZE }, 134 [TCA_POLICE_PEAKRATE] = { .len = TC_RTAB_SIZE }, 135 [TCA_POLICE_AVRATE] = { .type = NLA_U32 }, 136 [TCA_POLICE_RESULT] = { .type = NLA_U32 }, 137}; 138 139static int tcf_act_police_locate(struct nlattr *nla, struct nlattr *est, 140 struct tc_action *a, int ovr, int bind) 141{ 142 unsigned h; 143 int ret = 0, err; 144 struct nlattr *tb[TCA_POLICE_MAX + 1]; 145 struct tc_police *parm; 146 struct tcf_police *police; 147 struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL; 148 int size; 149 150 if (nla == NULL) 151 return -EINVAL; 152 153 err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy); 154 if (err < 0) 155 return err; 156 157 if (tb[TCA_POLICE_TBF] == NULL) 158 return -EINVAL; 159 size = nla_len(tb[TCA_POLICE_TBF]); 160 if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat)) 161 return -EINVAL; 162 parm = nla_data(tb[TCA_POLICE_TBF]); 163 164 if (parm->index) { 165 struct tcf_common *pc; 166 167 pc = tcf_hash_lookup(parm->index, &police_hash_info); 168 if (pc != NULL) { 169 a->priv = pc; 170 police = to_police(pc); 171 if (bind) { 172 police->tcf_bindcnt += 1; 173 police->tcf_refcnt += 1; 174 } 175 if (ovr) 176 goto override; 177 return ret; 178 } 179 } 180 181 police = kzalloc(sizeof(*police), GFP_KERNEL); 182 if (police == NULL) 183 return -ENOMEM; 184 ret = ACT_P_CREATED; 185 police->tcf_refcnt = 1; 186 spin_lock_init(&police->tcf_lock); 187 if (bind) 188 police->tcf_bindcnt = 1; 189override: 190 if (parm->rate.rate) { 191 err = -ENOMEM; 192 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]); 193 if (R_tab == NULL) 194 goto failure; 195 196 if (parm->peakrate.rate) { 197 P_tab = qdisc_get_rtab(&parm->peakrate, 198 tb[TCA_POLICE_PEAKRATE]); 199 if (P_tab == NULL) 200 goto failure; 201 } 202 } 203 204 spin_lock_bh(&police->tcf_lock); 205 if (est) { 206 err = gen_replace_estimator(&police->tcf_bstats, 207 &police->tcf_rate_est, 208 &police->tcf_lock, est); 209 if (err) 210 goto failure_unlock; 211 } else if (tb[TCA_POLICE_AVRATE] && 212 (ret == ACT_P_CREATED || 213 !gen_estimator_active(&police->tcf_bstats, 214 &police->tcf_rate_est))) { 215 err = -EINVAL; 216 goto failure_unlock; 217 } 218 219 /* No failure allowed after this point */ 220 if (R_tab != NULL) { 221 qdisc_put_rtab(police->tcfp_R_tab); 222 police->tcfp_R_tab = R_tab; 223 } 224 if (P_tab != NULL) { 225 qdisc_put_rtab(police->tcfp_P_tab); 226 police->tcfp_P_tab = P_tab; 227 } 228 229 if (tb[TCA_POLICE_RESULT]) 230 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]); 231 police->tcfp_toks = police->tcfp_burst = parm->burst; 232 police->tcfp_mtu = parm->mtu; 233 if (police->tcfp_mtu == 0) { 234 police->tcfp_mtu = ~0; 235 if (police->tcfp_R_tab) 236 police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log; 237 } 238 if (police->tcfp_P_tab) 239 police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu); 240 police->tcf_action = parm->action; 241 242 if (tb[TCA_POLICE_AVRATE]) 243 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]); 244 245 spin_unlock_bh(&police->tcf_lock); 246 if (ret != ACT_P_CREATED) 247 return ret; 248 249 police->tcfp_t_c = psched_get_time(); 250 police->tcf_index = parm->index ? parm->index : 251 tcf_hash_new_index(&police_idx_gen, &police_hash_info); 252 h = tcf_hash(police->tcf_index, POL_TAB_MASK); 253 write_lock_bh(&police_lock); 254 police->tcf_next = tcf_police_ht[h]; 255 tcf_police_ht[h] = &police->common; 256 write_unlock_bh(&police_lock); 257 258 a->priv = police; 259 return ret; 260 261failure_unlock: 262 spin_unlock_bh(&police->tcf_lock); 263failure: 264 if (P_tab) 265 qdisc_put_rtab(P_tab); 266 if (R_tab) 267 qdisc_put_rtab(R_tab); 268 if (ret == ACT_P_CREATED) 269 kfree(police); 270 return err; 271} 272 273static int tcf_act_police_cleanup(struct tc_action *a, int bind) 274{ 275 struct tcf_police *p = a->priv; 276 int ret = 0; 277 278 if (p != NULL) { 279 if (bind) 280 p->tcf_bindcnt--; 281 282 p->tcf_refcnt--; 283 if (p->tcf_refcnt <= 0 && !p->tcf_bindcnt) { 284 tcf_police_destroy(p); 285 ret = 1; 286 } 287 } 288 return ret; 289} 290 291static int tcf_act_police(struct sk_buff *skb, struct tc_action *a, 292 struct tcf_result *res) 293{ 294 struct tcf_police *police = a->priv; 295 psched_time_t now; 296 long toks; 297 long ptoks = 0; 298 299 spin_lock(&police->tcf_lock); 300 301 police->tcf_bstats.bytes += qdisc_pkt_len(skb); 302 police->tcf_bstats.packets++; 303 304 if (police->tcfp_ewma_rate && 305 police->tcf_rate_est.bps >= police->tcfp_ewma_rate) { 306 police->tcf_qstats.overlimits++; 307 if (police->tcf_action == TC_ACT_SHOT) 308 police->tcf_qstats.drops++; 309 spin_unlock(&police->tcf_lock); 310 return police->tcf_action; 311 } 312 313 if (qdisc_pkt_len(skb) <= police->tcfp_mtu) { 314 if (police->tcfp_R_tab == NULL) { 315 spin_unlock(&police->tcf_lock); 316 return police->tcfp_result; 317 } 318 319 now = psched_get_time(); 320 toks = psched_tdiff_bounded(now, police->tcfp_t_c, 321 police->tcfp_burst); 322 if (police->tcfp_P_tab) { 323 ptoks = toks + police->tcfp_ptoks; 324 if (ptoks > (long)L2T_P(police, police->tcfp_mtu)) 325 ptoks = (long)L2T_P(police, police->tcfp_mtu); 326 ptoks -= L2T_P(police, qdisc_pkt_len(skb)); 327 } 328 toks += police->tcfp_toks; 329 if (toks > (long)police->tcfp_burst) 330 toks = police->tcfp_burst; 331 toks -= L2T(police, qdisc_pkt_len(skb)); 332 if ((toks|ptoks) >= 0) { 333 police->tcfp_t_c = now; 334 police->tcfp_toks = toks; 335 police->tcfp_ptoks = ptoks; 336 spin_unlock(&police->tcf_lock); 337 return police->tcfp_result; 338 } 339 } 340 341 police->tcf_qstats.overlimits++; 342 if (police->tcf_action == TC_ACT_SHOT) 343 police->tcf_qstats.drops++; 344 spin_unlock(&police->tcf_lock); 345 return police->tcf_action; 346} 347 348static int 349tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 350{ 351 unsigned char *b = skb_tail_pointer(skb); 352 struct tcf_police *police = a->priv; 353 struct tc_police opt = { 354 .index = police->tcf_index, 355 .action = police->tcf_action, 356 .mtu = police->tcfp_mtu, 357 .burst = police->tcfp_burst, 358 .refcnt = police->tcf_refcnt - ref, 359 .bindcnt = police->tcf_bindcnt - bind, 360 }; 361 362 if (police->tcfp_R_tab) 363 opt.rate = police->tcfp_R_tab->rate; 364 if (police->tcfp_P_tab) 365 opt.peakrate = police->tcfp_P_tab->rate; 366 NLA_PUT(skb, TCA_POLICE_TBF, sizeof(opt), &opt); 367 if (police->tcfp_result) 368 NLA_PUT_U32(skb, TCA_POLICE_RESULT, police->tcfp_result); 369 if (police->tcfp_ewma_rate) 370 NLA_PUT_U32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate); 371 return skb->len; 372 373nla_put_failure: 374 nlmsg_trim(skb, b); 375 return -1; 376} 377 378MODULE_AUTHOR("Alexey Kuznetsov"); 379MODULE_DESCRIPTION("Policing actions"); 380MODULE_LICENSE("GPL"); 381 382static struct tc_action_ops act_police_ops = { 383 .kind = "police", 384 .hinfo = &police_hash_info, 385 .type = TCA_ID_POLICE, 386 .capab = TCA_CAP_NONE, 387 .owner = THIS_MODULE, 388 .act = tcf_act_police, 389 .dump = tcf_act_police_dump, 390 .cleanup = tcf_act_police_cleanup, 391 .lookup = tcf_hash_search, 392 .init = tcf_act_police_locate, 393 .walk = tcf_act_police_walker 394}; 395 396static int __init 397police_init_module(void) 398{ 399 return tcf_register_action(&act_police_ops); 400} 401 402static void __exit 403police_cleanup_module(void) 404{ 405 tcf_unregister_action(&act_police_ops); 406 rcu_barrier(); /* Wait for completion of call_rcu()'s (tcf_police_free_rcu) */ 407} 408 409module_init(police_init_module); 410module_exit(police_cleanup_module); 411