| 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); |