linux/net/sched/act_simple.c
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   1/*
   2 * net/sched/simp.c     Simple example of an action
   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:     Jamal Hadi Salim (2005-8)
  10 *
  11 */
  12
  13#include <linux/module.h>
  14#include <linux/slab.h>
  15#include <linux/init.h>
  16#include <linux/kernel.h>
  17#include <linux/skbuff.h>
  18#include <linux/rtnetlink.h>
  19#include <net/netlink.h>
  20#include <net/pkt_sched.h>
  21
  22#define TCA_ACT_SIMP 22
  23
  24#include <linux/tc_act/tc_defact.h>
  25#include <net/tc_act/tc_defact.h>
  26
  27#define SIMP_TAB_MASK     7
  28static struct tcf_common *tcf_simp_ht[SIMP_TAB_MASK + 1];
  29static u32 simp_idx_gen;
  30static DEFINE_RWLOCK(simp_lock);
  31
  32static struct tcf_hashinfo simp_hash_info = {
  33        .htab   =       tcf_simp_ht,
  34        .hmask  =       SIMP_TAB_MASK,
  35        .lock   =       &simp_lock,
  36};
  37
  38#define SIMP_MAX_DATA   32
  39static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
  40                    struct tcf_result *res)
  41{
  42        struct tcf_defact *d = a->priv;
  43
  44        spin_lock(&d->tcf_lock);
  45        d->tcf_tm.lastuse = jiffies;
  46        bstats_update(&d->tcf_bstats, skb);
  47
  48        /* print policy string followed by _ then packet count
  49         * Example if this was the 3rd packet and the string was "hello"
  50         * then it would look like "hello_3" (without quotes)
  51         */
  52        pr_info("simple: %s_%d\n",
  53               (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  54        spin_unlock(&d->tcf_lock);
  55        return d->tcf_action;
  56}
  57
  58static int tcf_simp_release(struct tcf_defact *d, int bind)
  59{
  60        int ret = 0;
  61        if (d) {
  62                if (bind)
  63                        d->tcf_bindcnt--;
  64                d->tcf_refcnt--;
  65                if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
  66                        kfree(d->tcfd_defdata);
  67                        tcf_hash_destroy(&d->common, &simp_hash_info);
  68                        ret = 1;
  69                }
  70        }
  71        return ret;
  72}
  73
  74static int alloc_defdata(struct tcf_defact *d, char *defdata)
  75{
  76        d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  77        if (unlikely(!d->tcfd_defdata))
  78                return -ENOMEM;
  79        strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  80        return 0;
  81}
  82
  83static void reset_policy(struct tcf_defact *d, char *defdata,
  84                         struct tc_defact *p)
  85{
  86        spin_lock_bh(&d->tcf_lock);
  87        d->tcf_action = p->action;
  88        memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  89        strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  90        spin_unlock_bh(&d->tcf_lock);
  91}
  92
  93static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  94        [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  95        [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  96};
  97
  98static int tcf_simp_init(struct nlattr *nla, struct nlattr *est,
  99                         struct tc_action *a, int ovr, int bind)
 100{
 101        struct nlattr *tb[TCA_DEF_MAX + 1];
 102        struct tc_defact *parm;
 103        struct tcf_defact *d;
 104        struct tcf_common *pc;
 105        char *defdata;
 106        int ret = 0, err;
 107
 108        if (nla == NULL)
 109                return -EINVAL;
 110
 111        err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
 112        if (err < 0)
 113                return err;
 114
 115        if (tb[TCA_DEF_PARMS] == NULL)
 116                return -EINVAL;
 117
 118        if (tb[TCA_DEF_DATA] == NULL)
 119                return -EINVAL;
 120
 121        parm = nla_data(tb[TCA_DEF_PARMS]);
 122        defdata = nla_data(tb[TCA_DEF_DATA]);
 123
 124        pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
 125        if (!pc) {
 126                pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
 127                                     &simp_idx_gen, &simp_hash_info);
 128                if (IS_ERR(pc))
 129                        return PTR_ERR(pc);
 130
 131                d = to_defact(pc);
 132                ret = alloc_defdata(d, defdata);
 133                if (ret < 0) {
 134                        if (est)
 135                                gen_kill_estimator(&pc->tcfc_bstats,
 136                                                   &pc->tcfc_rate_est);
 137                        kfree_rcu(pc, tcfc_rcu);
 138                        return ret;
 139                }
 140                d->tcf_action = parm->action;
 141                ret = ACT_P_CREATED;
 142        } else {
 143                d = to_defact(pc);
 144                if (!ovr) {
 145                        tcf_simp_release(d, bind);
 146                        return -EEXIST;
 147                }
 148                reset_policy(d, defdata, parm);
 149        }
 150
 151        if (ret == ACT_P_CREATED)
 152                tcf_hash_insert(pc, &simp_hash_info);
 153        return ret;
 154}
 155
 156static int tcf_simp_cleanup(struct tc_action *a, int bind)
 157{
 158        struct tcf_defact *d = a->priv;
 159
 160        if (d)
 161                return tcf_simp_release(d, bind);
 162        return 0;
 163}
 164
 165static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 166                         int bind, int ref)
 167{
 168        unsigned char *b = skb_tail_pointer(skb);
 169        struct tcf_defact *d = a->priv;
 170        struct tc_defact opt = {
 171                .index   = d->tcf_index,
 172                .refcnt  = d->tcf_refcnt - ref,
 173                .bindcnt = d->tcf_bindcnt - bind,
 174                .action  = d->tcf_action,
 175        };
 176        struct tcf_t t;
 177
 178        if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 179            nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 180                goto nla_put_failure;
 181        t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
 182        t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
 183        t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
 184        if (nla_put(skb, TCA_DEF_TM, sizeof(t), &t))
 185                goto nla_put_failure;
 186        return skb->len;
 187
 188nla_put_failure:
 189        nlmsg_trim(skb, b);
 190        return -1;
 191}
 192
 193static struct tc_action_ops act_simp_ops = {
 194        .kind           =       "simple",
 195        .hinfo          =       &simp_hash_info,
 196        .type           =       TCA_ACT_SIMP,
 197        .capab          =       TCA_CAP_NONE,
 198        .owner          =       THIS_MODULE,
 199        .act            =       tcf_simp,
 200        .dump           =       tcf_simp_dump,
 201        .cleanup        =       tcf_simp_cleanup,
 202        .init           =       tcf_simp_init,
 203        .walk           =       tcf_generic_walker,
 204};
 205
 206MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 207MODULE_DESCRIPTION("Simple example action");
 208MODULE_LICENSE("GPL");
 209
 210static int __init simp_init_module(void)
 211{
 212        int ret = tcf_register_action(&act_simp_ops);
 213        if (!ret)
 214                pr_info("Simple TC action Loaded\n");
 215        return ret;
 216}
 217
 218static void __exit simp_cleanup_module(void)
 219{
 220        tcf_unregister_action(&act_simp_ops);
 221}
 222
 223module_init(simp_init_module);
 224module_exit(simp_cleanup_module);
 225
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