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 29 static struct tcf_common *tcf_police_ht[POL_TAB_MASK + 1]; 30 static u32 police_idx_gen; 31 static DEFINE_RWLOCK(police_lock); 32 33 static 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 */ 40 struct tc_police_compat { 41 u32 index; 42 int action; 43 u32 limit; 44 u32 burst; 45 u32 mtu; 46 struct tc_ratespec rate; 47 struct tc_ratespec peakrate; 48 }; 49 50 /* Each policer is serialized by its individual spinlock */ 51 52 static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb, 53 int type, struct tc_action *a) 54 { 55 struct tcf_common *p; 56 int err = 0, index = -1, i = 0, s_i = 0, n_i = 0; 57 struct nlattr *nest; 58 59 read_lock_bh(&police_lock); 60 61 s_i = cb->args[0]; 62 63 for (i = 0; i < (POL_TAB_MASK + 1); i++) { 64 p = tcf_police_ht[tcf_hash(i, POL_TAB_MASK)]; 65 66 for (; p; p = p->tcfc_next) { 67 index++; 68 if (index < s_i) 69 continue; 70 a->priv = p; 71 a->order = index; 72 nest = nla_nest_start(skb, a->order); 73 if (nest == NULL) 74 goto nla_put_failure; 75 if (type == RTM_DELACTION) 76 err = tcf_action_dump_1(skb, a, 0, 1); 77 else 78 err = tcf_action_dump_1(skb, a, 0, 0); 79 if (err < 0) { 80 index--; 81 nla_nest_cancel(skb, nest); 82 goto done; 83 } 84 nla_nest_end(skb, nest); 85 n_i++; 86 } 87 } 88 done: 89 read_unlock_bh(&police_lock); 90 if (n_i) 91 cb->args[0] += n_i; 92 return n_i; 93 94 nla_put_failure: 95 nla_nest_cancel(skb, nest); 96 goto done; 97 } 98 99 static void tcf_police_destroy(struct tcf_police *p) 100 { 101 unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK); 102 struct tcf_common **p1p; 103 104 for (p1p = &tcf_police_ht[h]; *p1p; p1p = &(*p1p)->tcfc_next) { 105 if (*p1p == &p->common) { 106 write_lock_bh(&police_lock); 107 *p1p = p->tcf_next; 108 write_unlock_bh(&police_lock); 109 gen_kill_estimator(&p->tcf_bstats, 110 &p->tcf_rate_est); 111 if (p->tcfp_R_tab) 112 qdisc_put_rtab(p->tcfp_R_tab); 113 if (p->tcfp_P_tab) 114 qdisc_put_rtab(p->tcfp_P_tab); 115 /* 116 * gen_estimator est_timer() might access p->tcf_lock 117 * or bstats, wait a RCU grace period before freeing p 118 */ 119 kfree_rcu(p, tcf_rcu); 120 return; 121 } 122 } 123 WARN_ON(1); 124 } 125 126 static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = { 127 [TCA_POLICE_RATE] = { .len = TC_RTAB_SIZE }, 128 [TCA_POLICE_PEAKRATE] = { .len = TC_RTAB_SIZE }, 129 [TCA_POLICE_AVRATE] = { .type = NLA_U32 }, 130 [TCA_POLICE_RESULT] = { .type = NLA_U32 }, 131 }; 132 133 static int tcf_act_police_locate(struct nlattr *nla, struct nlattr *est, 134 struct tc_action *a, int ovr, int bind) 135 { 136 unsigned int h; 137 int ret = 0, err; 138 struct nlattr *tb[TCA_POLICE_MAX + 1]; 139 struct tc_police *parm; 140 struct tcf_police *police; 141 struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL; 142 int size; 143 144 if (nla == NULL) 145 return -EINVAL; 146 147 err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy); 148 if (err < 0) 149 return err; 150 151 if (tb[TCA_POLICE_TBF] == NULL) 152 return -EINVAL; 153 size = nla_len(tb[TCA_POLICE_TBF]); 154 if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat)) 155 return -EINVAL; 156 parm = nla_data(tb[TCA_POLICE_TBF]); 157 158 if (parm->index) { 159 struct tcf_common *pc; 160 161 pc = tcf_hash_lookup(parm->index, &police_hash_info); 162 if (pc != NULL) { 163 a->priv = pc; 164 police = to_police(pc); 165 if (bind) { 166 police->tcf_bindcnt += 1; 167 police->tcf_refcnt += 1; 168 } 169 if (ovr) 170 goto override; 171 return ret; 172 } 173 } 174 175 police = kzalloc(sizeof(*police), GFP_KERNEL); 176 if (police == NULL) 177 return -ENOMEM; 178 ret = ACT_P_CREATED; 179 police->tcf_refcnt = 1; 180 spin_lock_init(&police->tcf_lock); 181 if (bind) 182 police->tcf_bindcnt = 1; 183 override: 184 if (parm->rate.rate) { 185 err = -ENOMEM; 186 R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]); 187 if (R_tab == NULL) 188 goto failure; 189 190 if (parm->peakrate.rate) { 191 P_tab = qdisc_get_rtab(&parm->peakrate, 192 tb[TCA_POLICE_PEAKRATE]); 193 if (P_tab == NULL) 194 goto failure; 195 } 196 } 197 198 spin_lock_bh(&police->tcf_lock); 199 if (est) { 200 err = gen_replace_estimator(&police->tcf_bstats, 201 &police->tcf_rate_est, 202 &police->tcf_lock, est); 203 if (err) 204 goto failure_unlock; 205 } else if (tb[TCA_POLICE_AVRATE] && 206 (ret == ACT_P_CREATED || 207 !gen_estimator_active(&police->tcf_bstats, 208 &police->tcf_rate_est))) { 209 err = -EINVAL; 210 goto failure_unlock; 211 } 212 213 /* No failure allowed after this point */ 214 if (R_tab != NULL) { 215 qdisc_put_rtab(police->tcfp_R_tab); 216 police->tcfp_R_tab = R_tab; 217 } 218 if (P_tab != NULL) { 219 qdisc_put_rtab(police->tcfp_P_tab); 220 police->tcfp_P_tab = P_tab; 221 } 222 223 if (tb[TCA_POLICE_RESULT]) 224 police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]); 225 police->tcfp_toks = police->tcfp_burst = parm->burst; 226 police->tcfp_mtu = parm->mtu; 227 if (police->tcfp_mtu == 0) { 228 police->tcfp_mtu = ~0; 229 if (police->tcfp_R_tab) 230 police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log; 231 } 232 if (police->tcfp_P_tab) 233 police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu); 234 police->tcf_action = parm->action; 235 236 if (tb[TCA_POLICE_AVRATE]) 237 police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]); 238 239 spin_unlock_bh(&police->tcf_lock); 240 if (ret != ACT_P_CREATED) 241 return ret; 242 243 police->tcfp_t_c = psched_get_time(); 244 police->tcf_index = parm->index ? parm->index : 245 tcf_hash_new_index(&police_idx_gen, &police_hash_info); 246 h = tcf_hash(police->tcf_index, POL_TAB_MASK); 247 write_lock_bh(&police_lock); 248 police->tcf_next = tcf_police_ht[h]; 249 tcf_police_ht[h] = &police->common; 250 write_unlock_bh(&police_lock); 251 252 a->priv = police; 253 return ret; 254 255 failure_unlock: 256 spin_unlock_bh(&police->tcf_lock); 257 failure: 258 if (P_tab) 259 qdisc_put_rtab(P_tab); 260 if (R_tab) 261 qdisc_put_rtab(R_tab); 262 if (ret == ACT_P_CREATED) 263 kfree(police); 264 return err; 265 } 266 267 static int tcf_act_police_cleanup(struct tc_action *a, int bind) 268 { 269 struct tcf_police *p = a->priv; 270 int ret = 0; 271 272 if (p != NULL) { 273 if (bind) 274 p->tcf_bindcnt--; 275 276 p->tcf_refcnt--; 277 if (p->tcf_refcnt <= 0 && !p->tcf_bindcnt) { 278 tcf_police_destroy(p); 279 ret = 1; 280 } 281 } 282 return ret; 283 } 284 285 static int tcf_act_police(struct sk_buff *skb, const struct tc_action *a, 286 struct tcf_result *res) 287 { 288 struct tcf_police *police = a->priv; 289 psched_time_t now; 290 long toks; 291 long ptoks = 0; 292 293 spin_lock(&police->tcf_lock); 294 295 bstats_update(&police->tcf_bstats, skb); 296 297 if (police->tcfp_ewma_rate && 298 police->tcf_rate_est.bps >= police->tcfp_ewma_rate) { 299 police->tcf_qstats.overlimits++; 300 if (police->tcf_action == TC_ACT_SHOT) 301 police->tcf_qstats.drops++; 302 spin_unlock(&police->tcf_lock); 303 return police->tcf_action; 304 } 305 306 if (qdisc_pkt_len(skb) <= police->tcfp_mtu) { 307 if (police->tcfp_R_tab == NULL) { 308 spin_unlock(&police->tcf_lock); 309 return police->tcfp_result; 310 } 311 312 now = psched_get_time(); 313 toks = psched_tdiff_bounded(now, police->tcfp_t_c, 314 police->tcfp_burst); 315 if (police->tcfp_P_tab) { 316 ptoks = toks + police->tcfp_ptoks; 317 if (ptoks > (long)L2T_P(police, police->tcfp_mtu)) 318 ptoks = (long)L2T_P(police, police->tcfp_mtu); 319 ptoks -= L2T_P(police, qdisc_pkt_len(skb)); 320 } 321 toks += police->tcfp_toks; 322 if (toks > (long)police->tcfp_burst) 323 toks = police->tcfp_burst; 324 toks -= L2T(police, qdisc_pkt_len(skb)); 325 if ((toks|ptoks) >= 0) { 326 police->tcfp_t_c = now; 327 police->tcfp_toks = toks; 328 police->tcfp_ptoks = ptoks; 329 spin_unlock(&police->tcf_lock); 330 return police->tcfp_result; 331 } 332 } 333 334 police->tcf_qstats.overlimits++; 335 if (police->tcf_action == TC_ACT_SHOT) 336 police->tcf_qstats.drops++; 337 spin_unlock(&police->tcf_lock); 338 return police->tcf_action; 339 } 340 341 static int 342 tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 343 { 344 unsigned char *b = skb_tail_pointer(skb); 345 struct tcf_police *police = a->priv; 346 struct tc_police opt = { 347 .index = police->tcf_index, 348 .action = police->tcf_action, 349 .mtu = police->tcfp_mtu, 350 .burst = police->tcfp_burst, 351 .refcnt = police->tcf_refcnt - ref, 352 .bindcnt = police->tcf_bindcnt - bind, 353 }; 354 355 if (police->tcfp_R_tab) 356 opt.rate = police->tcfp_R_tab->rate; 357 if (police->tcfp_P_tab) 358 opt.peakrate = police->tcfp_P_tab->rate; 359 if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt)) 360 goto nla_put_failure; 361 if (police->tcfp_result && 362 nla_put_u32(skb, TCA_POLICE_RESULT, police->tcfp_result)) 363 goto nla_put_failure; 364 if (police->tcfp_ewma_rate && 365 nla_put_u32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate)) 366 goto nla_put_failure; 367 return skb->len; 368 369 nla_put_failure: 370 nlmsg_trim(skb, b); 371 return -1; 372 } 373 374 MODULE_AUTHOR("Alexey Kuznetsov"); 375 MODULE_DESCRIPTION("Policing actions"); 376 MODULE_LICENSE("GPL"); 377 378 static struct tc_action_ops act_police_ops = { 379 .kind = "police", 380 .hinfo = &police_hash_info, 381 .type = TCA_ID_POLICE, 382 .capab = TCA_CAP_NONE, 383 .owner = THIS_MODULE, 384 .act = tcf_act_police, 385 .dump = tcf_act_police_dump, 386 .cleanup = tcf_act_police_cleanup, 387 .lookup = tcf_hash_search, 388 .init = tcf_act_police_locate, 389 .walk = tcf_act_police_walker 390 }; 391 392 static int __init 393 police_init_module(void) 394 { 395 return tcf_register_action(&act_police_ops); 396 } 397 398 static void __exit 399 police_cleanup_module(void) 400 { 401 tcf_unregister_action(&act_police_ops); 402 } 403 404 module_init(police_init_module); 405 module_exit(police_cleanup_module); 406