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