/* * net/sched/police.c Input police filter. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> * J Hadi Salim (action changes) */ #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/string.h> #include <linux/errno.h> #include <linux/skbuff.h> #include <linux/rtnetlink.h> #include <linux/init.h> #include <linux/slab.h> #include <net/act_api.h> #include <net/netlink.h> #define L2T(p,L) qdisc_l2t((p)->tcfp_R_tab, L) #define L2T_P(p,L) qdisc_l2t((p)->tcfp_P_tab, L) #define POL_TAB_MASK 15 static struct tcf_common *tcf_police_ht[POL_TAB_MASK + 1]; static u32 police_idx_gen; static DEFINE_RWLOCK(police_lock); static struct tcf_hashinfo police_hash_info = { .htab = tcf_police_ht, .hmask = POL_TAB_MASK, .lock = &police_lock, }; /* old policer structure from before tc actions */ struct tc_police_compat { u32 index; int action; u32 limit; u32 burst; u32 mtu; struct tc_ratespec rate; struct tc_ratespec peakrate; }; /* Each policer is serialized by its individual spinlock */ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb, int type, struct tc_action *a) { struct tcf_common *p; int err = 0, index = -1, i = 0, s_i = 0, n_i = 0; struct nlattr *nest; read_lock_bh(&police_lock); s_i = cb->args[0]; for (i = 0; i < (POL_TAB_MASK + 1); i++) { p = tcf_police_ht[tcf_hash(i, POL_TAB_MASK)]; for (; p; p = p->tcfc_next) { index++; if (index < s_i) continue; a->priv = p; a->order = index; nest = nla_nest_start(skb, a->order); if (nest == NULL) goto nla_put_failure; if (type == RTM_DELACTION) err = tcf_action_dump_1(skb, a, 0, 1); else err = tcf_action_dump_1(skb, a, 0, 0); if (err < 0) { index--; nla_nest_cancel(skb, nest); goto done; } nla_nest_end(skb, nest); n_i++; } } done: read_unlock_bh(&police_lock); if (n_i) cb->args[0] += n_i; return n_i; nla_put_failure: nla_nest_cancel(skb, nest); goto done; } static void tcf_police_free_rcu(struct rcu_head *head) { kfree(container_of(head, struct tcf_police, tcf_rcu)); } static void tcf_police_destroy(struct tcf_police *p) { unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK); struct tcf_common **p1p; for (p1p = &tcf_police_ht[h]; *p1p; p1p = &(*p1p)->tcfc_next) { if (*p1p == &p->common) { write_lock_bh(&police_lock); *p1p = p->tcf_next; write_unlock_bh(&police_lock); gen_kill_estimator(&p->tcf_bstats, &p->tcf_rate_est); if (p->tcfp_R_tab) qdisc_put_rtab(p->tcfp_R_tab); if (p->tcfp_P_tab) qdisc_put_rtab(p->tcfp_P_tab); /* * gen_estimator est_timer() might access p->tcf_lock * or bstats, wait a RCU grace period before freeing p */ call_rcu(&p->tcf_rcu, tcf_police_free_rcu); return; } } WARN_ON(1); } static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = { [TCA_POLICE_RATE] = { .len = TC_RTAB_SIZE }, [TCA_POLICE_PEAKRATE] = { .len = TC_RTAB_SIZE }, [TCA_POLICE_AVRATE] = { .type = NLA_U32 }, [TCA_POLICE_RESULT] = { .type = NLA_U32 }, }; static int tcf_act_police_locate(struct nlattr *nla, struct nlattr *est, struct tc_action *a, int ovr, int bind) { unsigned h; int ret = 0, err; struct nlattr *tb[TCA_POLICE_MAX + 1]; struct tc_police *parm; struct tcf_police *police; struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL; int size; if (nla == NULL) return -EINVAL; err = nla_parse_nested(tb, TCA_POLICE_MAX, nla, police_policy); if (err < 0) return err; if (tb[TCA_POLICE_TBF] == NULL) return -EINVAL; size = nla_len(tb[TCA_POLICE_TBF]); if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat)) return -EINVAL; parm = nla_data(tb[TCA_POLICE_TBF]); if (parm->index) { struct tcf_common *pc; pc = tcf_hash_lookup(parm->index, &police_hash_info); if (pc != NULL) { a->priv = pc; police = to_police(pc); if (bind) { police->tcf_bindcnt += 1; police->tcf_refcnt += 1; } if (ovr) goto override; return ret; } } police = kzalloc(sizeof(*police), GFP_KERNEL); if (police == NULL) return -ENOMEM; ret = ACT_P_CREATED; police->tcf_refcnt = 1; spin_lock_init(&police->tcf_lock); if (bind) police->tcf_bindcnt = 1; override: if (parm->rate.rate) { err = -ENOMEM; R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE]); if (R_tab == NULL) goto failure; if (parm->peakrate.rate) { P_tab = qdisc_get_rtab(&parm->peakrate, tb[TCA_POLICE_PEAKRATE]); if (P_tab == NULL) goto failure; } } spin_lock_bh(&police->tcf_lock); if (est) { err = gen_replace_estimator(&police->tcf_bstats, &police->tcf_rate_est, &police->tcf_lock, est); if (err) goto failure_unlock; } else if (tb[TCA_POLICE_AVRATE] && (ret == ACT_P_CREATED || !gen_estimator_active(&police->tcf_bstats, &police->tcf_rate_est))) { err = -EINVAL; goto failure_unlock; } /* No failure allowed after this point */ if (R_tab != NULL) { qdisc_put_rtab(police->tcfp_R_tab); police->tcfp_R_tab = R_tab; } if (P_tab != NULL) { qdisc_put_rtab(police->tcfp_P_tab); police->tcfp_P_tab = P_tab; } if (tb[TCA_POLICE_RESULT]) police->tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]); police->tcfp_toks = police->tcfp_burst = parm->burst; police->tcfp_mtu = parm->mtu; if (police->tcfp_mtu == 0) { police->tcfp_mtu = ~0; if (police->tcfp_R_tab) police->tcfp_mtu = 255<<police->tcfp_R_tab->rate.cell_log; } if (police->tcfp_P_tab) police->tcfp_ptoks = L2T_P(police, police->tcfp_mtu); police->tcf_action = parm->action; if (tb[TCA_POLICE_AVRATE]) police->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]); spin_unlock_bh(&police->tcf_lock); if (ret != ACT_P_CREATED) return ret; police->tcfp_t_c = psched_get_time(); police->tcf_index = parm->index ? parm->index : tcf_hash_new_index(&police_idx_gen, &police_hash_info); h = tcf_hash(police->tcf_index, POL_TAB_MASK); write_lock_bh(&police_lock); police->tcf_next = tcf_police_ht[h]; tcf_police_ht[h] = &police->common; write_unlock_bh(&police_lock); a->priv = police; return ret; failure_unlock: spin_unlock_bh(&police->tcf_lock); failure: if (P_tab) qdisc_put_rtab(P_tab); if (R_tab) qdisc_put_rtab(R_tab); if (ret == ACT_P_CREATED) kfree(police); return err; } static int tcf_act_police_cleanup(struct tc_action *a, int bind) { struct tcf_police *p = a->priv; int ret = 0; if (p != NULL) { if (bind) p->tcf_bindcnt--; p->tcf_refcnt--; if (p->tcf_refcnt <= 0 && !p->tcf_bindcnt) { tcf_police_destroy(p); ret = 1; } } return ret; } static int tcf_act_police(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res) { struct tcf_police *police = a->priv; psched_time_t now; long toks; long ptoks = 0; spin_lock(&police->tcf_lock); police->tcf_bstats.bytes += qdisc_pkt_len(skb); police->tcf_bstats.packets++; if (police->tcfp_ewma_rate && police->tcf_rate_est.bps >= police->tcfp_ewma_rate) { police->tcf_qstats.overlimits++; if (police->tcf_action == TC_ACT_SHOT) police->tcf_qstats.drops++; spin_unlock(&police->tcf_lock); return police->tcf_action; } if (qdisc_pkt_len(skb) <= police->tcfp_mtu) { if (police->tcfp_R_tab == NULL) { spin_unlock(&police->tcf_lock); return police->tcfp_result; } now = psched_get_time(); toks = psched_tdiff_bounded(now, police->tcfp_t_c, police->tcfp_burst); if (police->tcfp_P_tab) { ptoks = toks + police->tcfp_ptoks; if (ptoks > (long)L2T_P(police, police->tcfp_mtu)) ptoks = (long)L2T_P(police, police->tcfp_mtu); ptoks -= L2T_P(police, qdisc_pkt_len(skb)); } toks += police->tcfp_toks; if (toks > (long)police->tcfp_burst) toks = police->tcfp_burst; toks -= L2T(police, qdisc_pkt_len(skb)); if ((toks|ptoks) >= 0) { police->tcfp_t_c = now; police->tcfp_toks = toks; police->tcfp_ptoks = ptoks; spin_unlock(&police->tcf_lock); return police->tcfp_result; } } police->tcf_qstats.overlimits++; if (police->tcf_action == TC_ACT_SHOT) police->tcf_qstats.drops++; spin_unlock(&police->tcf_lock); return police->tcf_action; } static int tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) { unsigned char *b = skb_tail_pointer(skb); struct tcf_police *police = a->priv; struct tc_police opt = { .index = police->tcf_index, .action = police->tcf_action, .mtu = police->tcfp_mtu, .burst = police->tcfp_burst, .refcnt = police->tcf_refcnt - ref, .bindcnt = police->tcf_bindcnt - bind, }; if (police->tcfp_R_tab) opt.rate = police->tcfp_R_tab->rate; if (police->tcfp_P_tab) opt.peakrate = police->tcfp_P_tab->rate; NLA_PUT(skb, TCA_POLICE_TBF, sizeof(opt), &opt); if (police->tcfp_result) NLA_PUT_U32(skb, TCA_POLICE_RESULT, police->tcfp_result); if (police->tcfp_ewma_rate) NLA_PUT_U32(skb, TCA_POLICE_AVRATE, police->tcfp_ewma_rate); return skb->len; nla_put_failure: nlmsg_trim(skb, b); return -1; } MODULE_AUTHOR("Alexey Kuznetsov"); MODULE_DESCRIPTION("Policing actions"); MODULE_LICENSE("GPL"); static struct tc_action_ops act_police_ops = { .kind = "police", .hinfo = &police_hash_info, .type = TCA_ID_POLICE, .capab = TCA_CAP_NONE, .owner = THIS_MODULE, .act = tcf_act_police, .dump = tcf_act_police_dump, .cleanup = tcf_act_police_cleanup, .lookup = tcf_hash_search, .init = tcf_act_police_locate, .walk = tcf_act_police_walker }; static int __init police_init_module(void) { return tcf_register_action(&act_police_ops); } static void __exit police_cleanup_module(void) { tcf_unregister_action(&act_police_ops); rcu_barrier(); /* Wait for completion of call_rcu()'s (tcf_police_free_rcu) */ } module_init(police_init_module); module_exit(police_cleanup_module);