linux/net/sched/act_gact.c
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   1/*
   2 * net/sched/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
  27static struct tcf_common *tcf_gact_ht[GACT_TAB_MASK + 1];
  28static u32 gact_idx_gen;
  29static DEFINE_RWLOCK(gact_lock);
  30
  31static struct tcf_hashinfo gact_hash_info = {
  32        .htab   =       tcf_gact_ht,
  33        .hmask  =       GACT_TAB_MASK,
  34        .lock   =       &gact_lock,
  35};
  36
  37#ifdef CONFIG_GACT_PROB
  38static int gact_net_rand(struct tcf_gact *gact)
  39{
  40        if (!gact->tcfg_pval || net_random() % gact->tcfg_pval)
  41                return gact->tcf_action;
  42        return gact->tcfg_paction;
  43}
  44
  45static int gact_determ(struct tcf_gact *gact)
  46{
  47        if (!gact->tcfg_pval || gact->tcf_bstats.packets % gact->tcfg_pval)
  48                return gact->tcf_action;
  49        return gact->tcfg_paction;
  50}
  51
  52typedef int (*g_rand)(struct tcf_gact *gact);
  53static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  54#endif /* CONFIG_GACT_PROB */
  55
  56static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  57        [TCA_GACT_PARMS]        = { .len = sizeof(struct tc_gact) },
  58        [TCA_GACT_PROB]         = { .len = sizeof(struct tc_gact_p) },
  59};
  60
  61static int tcf_gact_init(struct nlattr *nla, struct nlattr *est,
  62                         struct tc_action *a, int ovr, int bind)
  63{
  64        struct nlattr *tb[TCA_GACT_MAX + 1];
  65        struct tc_gact *parm;
  66        struct tcf_gact *gact;
  67        struct tcf_common *pc;
  68        int ret = 0;
  69        int err;
  70
  71        if (nla == NULL)
  72                return -EINVAL;
  73
  74        err = nla_parse_nested(tb, TCA_GACT_MAX, nla, gact_policy);
  75        if (err < 0)
  76                return err;
  77
  78        if (tb[TCA_GACT_PARMS] == NULL)
  79                return -EINVAL;
  80        parm = nla_data(tb[TCA_GACT_PARMS]);
  81
  82#ifndef CONFIG_GACT_PROB
  83        if (tb[TCA_GACT_PROB] != NULL)
  84                return -EOPNOTSUPP;
  85#endif
  86
  87        pc = tcf_hash_check(parm->index, a, bind, &gact_hash_info);
  88        if (!pc) {
  89                pc = tcf_hash_create(parm->index, est, a, sizeof(*gact),
  90                                     bind, &gact_idx_gen, &gact_hash_info);
  91                if (IS_ERR(pc))
  92                        return PTR_ERR(pc);
  93                ret = ACT_P_CREATED;
  94        } else {
  95                if (!ovr) {
  96                        tcf_hash_release(pc, bind, &gact_hash_info);
  97                        return -EEXIST;
  98                }
  99        }
 100
 101        gact = to_gact(pc);
 102
 103        spin_lock_bh(&gact->tcf_lock);
 104        gact->tcf_action = parm->action;
 105#ifdef CONFIG_GACT_PROB
 106        if (tb[TCA_GACT_PROB] != NULL) {
 107                struct tc_gact_p *p_parm = nla_data(tb[TCA_GACT_PROB]);
 108                gact->tcfg_paction = p_parm->paction;
 109                gact->tcfg_pval    = p_parm->pval;
 110                gact->tcfg_ptype   = p_parm->ptype;
 111        }
 112#endif
 113        spin_unlock_bh(&gact->tcf_lock);
 114        if (ret == ACT_P_CREATED)
 115                tcf_hash_insert(pc, &gact_hash_info);
 116        return ret;
 117}
 118
 119static int tcf_gact_cleanup(struct tc_action *a, int bind)
 120{
 121        struct tcf_gact *gact = a->priv;
 122
 123        if (gact)
 124                return tcf_hash_release(&gact->common, bind, &gact_hash_info);
 125        return 0;
 126}
 127
 128static int tcf_gact(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
 129{
 130        struct tcf_gact *gact = a->priv;
 131        int action = TC_ACT_SHOT;
 132
 133        spin_lock(&gact->tcf_lock);
 134#ifdef CONFIG_GACT_PROB
 135        if (gact->tcfg_ptype && gact_rand[gact->tcfg_ptype] != NULL)
 136                action = gact_rand[gact->tcfg_ptype](gact);
 137        else
 138                action = gact->tcf_action;
 139#else
 140        action = gact->tcf_action;
 141#endif
 142        gact->tcf_bstats.bytes += qdisc_pkt_len(skb);
 143        gact->tcf_bstats.packets++;
 144        if (action == TC_ACT_SHOT)
 145                gact->tcf_qstats.drops++;
 146        gact->tcf_tm.lastuse = jiffies;
 147        spin_unlock(&gact->tcf_lock);
 148
 149        return action;
 150}
 151
 152static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 153{
 154        unsigned char *b = skb_tail_pointer(skb);
 155        struct tcf_gact *gact = a->priv;
 156        struct tc_gact opt = {
 157                .index   = gact->tcf_index,
 158                .refcnt  = gact->tcf_refcnt - ref,
 159                .bindcnt = gact->tcf_bindcnt - bind,
 160                .action  = gact->tcf_action,
 161        };
 162        struct tcf_t t;
 163
 164        NLA_PUT(skb, TCA_GACT_PARMS, sizeof(opt), &opt);
 165#ifdef CONFIG_GACT_PROB
 166        if (gact->tcfg_ptype) {
 167                struct tc_gact_p p_opt = {
 168                        .paction = gact->tcfg_paction,
 169                        .pval    = gact->tcfg_pval,
 170                        .ptype   = gact->tcfg_ptype,
 171                };
 172
 173                NLA_PUT(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt);
 174        }
 175#endif
 176        t.install = jiffies_to_clock_t(jiffies - gact->tcf_tm.install);
 177        t.lastuse = jiffies_to_clock_t(jiffies - gact->tcf_tm.lastuse);
 178        t.expires = jiffies_to_clock_t(gact->tcf_tm.expires);
 179        NLA_PUT(skb, TCA_GACT_TM, sizeof(t), &t);
 180        return skb->len;
 181
 182nla_put_failure:
 183        nlmsg_trim(skb, b);
 184        return -1;
 185}
 186
 187static struct tc_action_ops act_gact_ops = {
 188        .kind           =       "gact",
 189        .hinfo          =       &gact_hash_info,
 190        .type           =       TCA_ACT_GACT,
 191        .capab          =       TCA_CAP_NONE,
 192        .owner          =       THIS_MODULE,
 193        .act            =       tcf_gact,
 194        .dump           =       tcf_gact_dump,
 195        .cleanup        =       tcf_gact_cleanup,
 196        .lookup         =       tcf_hash_search,
 197        .init           =       tcf_gact_init,
 198        .walk           =       tcf_generic_walker
 199};
 200
 201MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 202MODULE_DESCRIPTION("Generic Classifier actions");
 203MODULE_LICENSE("GPL");
 204
 205static int __init gact_init_module(void)
 206{
 207#ifdef CONFIG_GACT_PROB
 208        pr_info("GACT probability on\n");
 209#else
 210        pr_info("GACT probability NOT on\n");
 211#endif
 212        return tcf_register_action(&act_gact_ops);
 213}
 214
 215static void __exit gact_cleanup_module(void)
 216{
 217        tcf_unregister_action(&act_gact_ops);
 218}
 219
 220module_init(gact_init_module);
 221module_exit(gact_cleanup_module);
 222