root/net/sched/act_simple.c

DEFINITIONS

1. tcf_simp
2. tcf_simp_release
3. alloc_defdata
4. reset_policy
5. tcf_simp_init
6. tcf_simp_cleanup
7. tcf_simp_dump
8. simp_init_module
9. simp_cleanup_module

/*
 * net/sched/simp.c     Simple example of an action
 *
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Authors:     Jamal Hadi Salim (2005-8)
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>

#define TCA_ACT_SIMP 22

#include <linux/tc_act/tc_defact.h>
#include <net/tc_act/tc_defact.h>

#define SIMP_TAB_MASK     7
static struct tcf_common *tcf_simp_ht[SIMP_TAB_MASK + 1];
static u32 simp_idx_gen;
static DEFINE_RWLOCK(simp_lock);

static struct tcf_hashinfo simp_hash_info = {
        .htab   =       tcf_simp_ht,
        .hmask  =       SIMP_TAB_MASK,
        .lock   =       &simp_lock,
};

#define SIMP_MAX_DATA   32
static int tcf_simp(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
{
        struct tcf_defact *d = a->priv;

        spin_lock(&d->tcf_lock);
        d->tcf_tm.lastuse = jiffies;
        d->tcf_bstats.bytes += qdisc_pkt_len(skb);
        d->tcf_bstats.packets++;

        /* print policy string followed by _ then packet count
         * Example if this was the 3rd packet and the string was "hello"
         * then it would look like "hello_3" (without quotes)
         **/
        printk("simple: %s_%d\n",
               (char *)d->tcfd_defdata, d->tcf_bstats.packets);
        spin_unlock(&d->tcf_lock);
        return d->tcf_action;
}

static int tcf_simp_release(struct tcf_defact *d, int bind)
{
        int ret = 0;
        if (d) {
                if (bind)
                        d->tcf_bindcnt--;
                d->tcf_refcnt--;
                if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
                        kfree(d->tcfd_defdata);
                        tcf_hash_destroy(&d->common, &simp_hash_info);
                        ret = 1;
                }
        }
        return ret;
}

static int alloc_defdata(struct tcf_defact *d, char *defdata)
{
        d->tcfd_defdata = kstrndup(defdata, SIMP_MAX_DATA, GFP_KERNEL);
        if (unlikely(!d->tcfd_defdata))
                return -ENOMEM;

        return 0;
}

static void reset_policy(struct tcf_defact *d, char *defdata,
                         struct tc_defact *p)
{
        spin_lock_bh(&d->tcf_lock);
        d->tcf_action = p->action;
        memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
        strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
        spin_unlock_bh(&d->tcf_lock);
}

static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
        [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
        [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
};

static int tcf_simp_init(struct nlattr *nla, struct nlattr *est,
                         struct tc_action *a, int ovr, int bind)
{
        struct nlattr *tb[TCA_DEF_MAX + 1];
        struct tc_defact *parm;
        struct tcf_defact *d;
        struct tcf_common *pc;
        char *defdata;
        int ret = 0, err;

        if (nla == NULL)
                return -EINVAL;

        err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
        if (err < 0)
                return err;

        if (tb[TCA_DEF_PARMS] == NULL)
                return -EINVAL;

        if (tb[TCA_DEF_DATA] == NULL)
                return -EINVAL;

        parm = nla_data(tb[TCA_DEF_PARMS]);
        defdata = nla_data(tb[TCA_DEF_DATA]);

        pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
        if (!pc) {
                pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
                                     &simp_idx_gen, &simp_hash_info);
                if (unlikely(!pc))
                        return -ENOMEM;

                d = to_defact(pc);
                ret = alloc_defdata(d, defdata);
                if (ret < 0) {
                        kfree(pc);
                        return ret;
                }
                d->tcf_action = parm->action;
                ret = ACT_P_CREATED;
        } else {
                d = to_defact(pc);
                if (!ovr) {
                        tcf_simp_release(d, bind);
                        return -EEXIST;
                }
                reset_policy(d, defdata, parm);
        }

        if (ret == ACT_P_CREATED)
                tcf_hash_insert(pc, &simp_hash_info);
        return ret;
}

static inline int tcf_simp_cleanup(struct tc_action *a, int bind)
{
        struct tcf_defact *d = a->priv;

        if (d)
                return tcf_simp_release(d, bind);
        return 0;
}

static inline int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
                                int bind, int ref)
{
        unsigned char *b = skb_tail_pointer(skb);
        struct tcf_defact *d = a->priv;
        struct tc_defact opt;
        struct tcf_t t;

        opt.index = d->tcf_index;
        opt.refcnt = d->tcf_refcnt - ref;
        opt.bindcnt = d->tcf_bindcnt - bind;
        opt.action = d->tcf_action;
        NLA_PUT(skb, TCA_DEF_PARMS, sizeof(opt), &opt);
        NLA_PUT_STRING(skb, TCA_DEF_DATA, d->tcfd_defdata);
        t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
        t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
        t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
        NLA_PUT(skb, TCA_DEF_TM, sizeof(t), &t);
        return skb->len;

nla_put_failure:
        nlmsg_trim(skb, b);
        return -1;
}

static struct tc_action_ops act_simp_ops = {
        .kind           =       "simple",
        .hinfo          =       &simp_hash_info,
        .type           =       TCA_ACT_SIMP,
        .capab          =       TCA_CAP_NONE,
        .owner          =       THIS_MODULE,
        .act            =       tcf_simp,
        .dump           =       tcf_simp_dump,
        .cleanup        =       tcf_simp_cleanup,
        .init           =       tcf_simp_init,
        .walk           =       tcf_generic_walker,
};

MODULE_AUTHOR("Jamal Hadi Salim(2005)");
MODULE_DESCRIPTION("Simple example action");
MODULE_LICENSE("GPL");

static int __init simp_init_module(void)
{
        int ret = tcf_register_action(&act_simp_ops);
        if (!ret)
                printk("Simple TC action Loaded\n");
        return ret;
}

static void __exit simp_cleanup_module(void)
{
        tcf_unregister_action(&act_simp_ops);
}

module_init(simp_init_module);
module_exit(simp_cleanup_module);