1 /* 2 * net/sched/act_gact.c Generic actions 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 * copyright Jamal Hadi Salim (2002-4) 10 * 11 */ 12 13 #include <linux/types.h> 14 #include <linux/kernel.h> 15 #include <linux/string.h> 16 #include <linux/errno.h> 17 #include <linux/skbuff.h> 18 #include <linux/rtnetlink.h> 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <net/netlink.h> 22 #include <net/pkt_sched.h> 23 #include <linux/tc_act/tc_gact.h> 24 #include <net/tc_act/tc_gact.h> 25 26 #define GACT_TAB_MASK 15 27 28 #ifdef CONFIG_GACT_PROB 29 static int gact_net_rand(struct tcf_gact *gact) 30 { 31 smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */ 32 if (prandom_u32() % gact->tcfg_pval) 33 return gact->tcf_action; 34 return gact->tcfg_paction; 35 } 36 37 static int gact_determ(struct tcf_gact *gact) 38 { 39 u32 pack = atomic_inc_return(&gact->packets); 40 41 smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */ 42 if (pack % gact->tcfg_pval) 43 return gact->tcf_action; 44 return gact->tcfg_paction; 45 } 46 47 typedef int (*g_rand)(struct tcf_gact *gact); 48 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ }; 49 #endif /* CONFIG_GACT_PROB */ 50 51 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = { 52 [TCA_GACT_PARMS] = { .len = sizeof(struct tc_gact) }, 53 [TCA_GACT_PROB] = { .len = sizeof(struct tc_gact_p) }, 54 }; 55 56 static int tcf_gact_init(struct net *net, struct nlattr *nla, 57 struct nlattr *est, struct tc_action *a, 58 int ovr, int bind) 59 { 60 struct nlattr *tb[TCA_GACT_MAX + 1]; 61 struct tc_gact *parm; 62 struct tcf_gact *gact; 63 int ret = 0; 64 int err; 65 #ifdef CONFIG_GACT_PROB 66 struct tc_gact_p *p_parm = NULL; 67 #endif 68 69 if (nla == NULL) 70 return -EINVAL; 71 72 err = nla_parse_nested(tb, TCA_GACT_MAX, nla, gact_policy); 73 if (err < 0) 74 return err; 75 76 if (tb[TCA_GACT_PARMS] == NULL) 77 return -EINVAL; 78 parm = nla_data(tb[TCA_GACT_PARMS]); 79 80 #ifndef CONFIG_GACT_PROB 81 if (tb[TCA_GACT_PROB] != NULL) 82 return -EOPNOTSUPP; 83 #else 84 if (tb[TCA_GACT_PROB]) { 85 p_parm = nla_data(tb[TCA_GACT_PROB]); 86 if (p_parm->ptype >= MAX_RAND) 87 return -EINVAL; 88 } 89 #endif 90 91 if (!tcf_hash_check(parm->index, a, bind)) { 92 ret = tcf_hash_create(parm->index, est, a, sizeof(*gact), 93 bind, true); 94 if (ret) 95 return ret; 96 ret = ACT_P_CREATED; 97 } else { 98 if (bind)/* dont override defaults */ 99 return 0; 100 tcf_hash_release(a, bind); 101 if (!ovr) 102 return -EEXIST; 103 } 104 105 gact = to_gact(a); 106 107 ASSERT_RTNL(); 108 gact->tcf_action = parm->action; 109 #ifdef CONFIG_GACT_PROB 110 if (p_parm) { 111 gact->tcfg_paction = p_parm->paction; 112 gact->tcfg_pval = max_t(u16, 1, p_parm->pval); 113 /* Make sure tcfg_pval is written before tcfg_ptype 114 * coupled with smp_rmb() in gact_net_rand() & gact_determ() 115 */ 116 smp_wmb(); 117 gact->tcfg_ptype = p_parm->ptype; 118 } 119 #endif 120 if (ret == ACT_P_CREATED) 121 tcf_hash_insert(a); 122 return ret; 123 } 124 125 static int tcf_gact(struct sk_buff *skb, const struct tc_action *a, 126 struct tcf_result *res) 127 { 128 struct tcf_gact *gact = a->priv; 129 int action = READ_ONCE(gact->tcf_action); 130 131 #ifdef CONFIG_GACT_PROB 132 { 133 u32 ptype = READ_ONCE(gact->tcfg_ptype); 134 135 if (ptype) 136 action = gact_rand[ptype](gact); 137 } 138 #endif 139 bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb); 140 if (action == TC_ACT_SHOT) 141 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats)); 142 143 tcf_lastuse_update(&gact->tcf_tm); 144 145 return action; 146 } 147 148 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref) 149 { 150 unsigned char *b = skb_tail_pointer(skb); 151 struct tcf_gact *gact = a->priv; 152 struct tc_gact opt = { 153 .index = gact->tcf_index, 154 .refcnt = gact->tcf_refcnt - ref, 155 .bindcnt = gact->tcf_bindcnt - bind, 156 .action = gact->tcf_action, 157 }; 158 struct tcf_t t; 159 160 if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt)) 161 goto nla_put_failure; 162 #ifdef CONFIG_GACT_PROB 163 if (gact->tcfg_ptype) { 164 struct tc_gact_p p_opt = { 165 .paction = gact->tcfg_paction, 166 .pval = gact->tcfg_pval, 167 .ptype = gact->tcfg_ptype, 168 }; 169 170 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt)) 171 goto nla_put_failure; 172 } 173 #endif 174 t.install = jiffies_to_clock_t(jiffies - gact->tcf_tm.install); 175 t.lastuse = jiffies_to_clock_t(jiffies - gact->tcf_tm.lastuse); 176 t.expires = jiffies_to_clock_t(gact->tcf_tm.expires); 177 if (nla_put(skb, TCA_GACT_TM, sizeof(t), &t)) 178 goto nla_put_failure; 179 return skb->len; 180 181 nla_put_failure: 182 nlmsg_trim(skb, b); 183 return -1; 184 } 185 186 static struct tc_action_ops act_gact_ops = { 187 .kind = "gact", 188 .type = TCA_ACT_GACT, 189 .owner = THIS_MODULE, 190 .act = tcf_gact, 191 .dump = tcf_gact_dump, 192 .init = tcf_gact_init, 193 }; 194 195 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)"); 196 MODULE_DESCRIPTION("Generic Classifier actions"); 197 MODULE_LICENSE("GPL"); 198 199 static int __init gact_init_module(void) 200 { 201 #ifdef CONFIG_GACT_PROB 202 pr_info("GACT probability on\n"); 203 #else 204 pr_info("GACT probability NOT on\n"); 205 #endif 206 return tcf_register_action(&act_gact_ops, GACT_TAB_MASK); 207 } 208 209 static void __exit gact_cleanup_module(void) 210 { 211 tcf_unregister_action(&act_gact_ops); 212 } 213 214 module_init(gact_init_module); 215 module_exit(gact_cleanup_module); 216