linux/net/sched/act_simple.c
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   1/*
   2 * net/sched/act_simple.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
  28
  29static int simp_net_id;
  30
  31#define SIMP_MAX_DATA   32
  32static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
  33                    struct tcf_result *res)
  34{
  35        struct tcf_defact *d = a->priv;
  36
  37        spin_lock(&d->tcf_lock);
  38        d->tcf_tm.lastuse = jiffies;
  39        bstats_update(&d->tcf_bstats, skb);
  40
  41        /* print policy string followed by _ then packet count
  42         * Example if this was the 3rd packet and the string was "hello"
  43         * then it would look like "hello_3" (without quotes)
  44         */
  45        pr_info("simple: %s_%d\n",
  46               (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  47        spin_unlock(&d->tcf_lock);
  48        return d->tcf_action;
  49}
  50
  51static void tcf_simp_release(struct tc_action *a, int bind)
  52{
  53        struct tcf_defact *d = to_defact(a);
  54        kfree(d->tcfd_defdata);
  55}
  56
  57static int alloc_defdata(struct tcf_defact *d, char *defdata)
  58{
  59        d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  60        if (unlikely(!d->tcfd_defdata))
  61                return -ENOMEM;
  62        strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  63        return 0;
  64}
  65
  66static void reset_policy(struct tcf_defact *d, char *defdata,
  67                         struct tc_defact *p)
  68{
  69        spin_lock_bh(&d->tcf_lock);
  70        d->tcf_action = p->action;
  71        memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  72        strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  73        spin_unlock_bh(&d->tcf_lock);
  74}
  75
  76static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  77        [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  78        [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  79};
  80
  81static int tcf_simp_init(struct net *net, struct nlattr *nla,
  82                         struct nlattr *est, struct tc_action *a,
  83                         int ovr, int bind)
  84{
  85        struct tc_action_net *tn = net_generic(net, simp_net_id);
  86        struct nlattr *tb[TCA_DEF_MAX + 1];
  87        struct tc_defact *parm;
  88        struct tcf_defact *d;
  89        char *defdata;
  90        int ret = 0, err, exists = 0;
  91
  92        if (nla == NULL)
  93                return -EINVAL;
  94
  95        err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
  96        if (err < 0)
  97                return err;
  98
  99        if (tb[TCA_DEF_PARMS] == NULL)
 100                return -EINVAL;
 101
 102
 103        parm = nla_data(tb[TCA_DEF_PARMS]);
 104        exists = tcf_hash_check(tn, parm->index, a, bind);
 105        if (exists && bind)
 106                return 0;
 107
 108        if (tb[TCA_DEF_DATA] == NULL) {
 109                if (exists)
 110                        tcf_hash_release(a, bind);
 111                return -EINVAL;
 112        }
 113
 114        defdata = nla_data(tb[TCA_DEF_DATA]);
 115
 116        if (!exists) {
 117                ret = tcf_hash_create(tn, parm->index, est, a,
 118                                      sizeof(*d), bind, false);
 119                if (ret)
 120                        return ret;
 121
 122                d = to_defact(a);
 123                ret = alloc_defdata(d, defdata);
 124                if (ret < 0) {
 125                        tcf_hash_cleanup(a, est);
 126                        return ret;
 127                }
 128                d->tcf_action = parm->action;
 129                ret = ACT_P_CREATED;
 130        } else {
 131                d = to_defact(a);
 132
 133                tcf_hash_release(a, bind);
 134                if (!ovr)
 135                        return -EEXIST;
 136
 137                reset_policy(d, defdata, parm);
 138        }
 139
 140        if (ret == ACT_P_CREATED)
 141                tcf_hash_insert(tn, a);
 142        return ret;
 143}
 144
 145static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 146                         int bind, int ref)
 147{
 148        unsigned char *b = skb_tail_pointer(skb);
 149        struct tcf_defact *d = a->priv;
 150        struct tc_defact opt = {
 151                .index   = d->tcf_index,
 152                .refcnt  = d->tcf_refcnt - ref,
 153                .bindcnt = d->tcf_bindcnt - bind,
 154                .action  = d->tcf_action,
 155        };
 156        struct tcf_t t;
 157
 158        if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 159            nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 160                goto nla_put_failure;
 161        t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
 162        t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
 163        t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
 164        if (nla_put(skb, TCA_DEF_TM, sizeof(t), &t))
 165                goto nla_put_failure;
 166        return skb->len;
 167
 168nla_put_failure:
 169        nlmsg_trim(skb, b);
 170        return -1;
 171}
 172
 173static int tcf_simp_walker(struct net *net, struct sk_buff *skb,
 174                           struct netlink_callback *cb, int type,
 175                           struct tc_action *a)
 176{
 177        struct tc_action_net *tn = net_generic(net, simp_net_id);
 178
 179        return tcf_generic_walker(tn, skb, cb, type, a);
 180}
 181
 182static int tcf_simp_search(struct net *net, struct tc_action *a, u32 index)
 183{
 184        struct tc_action_net *tn = net_generic(net, simp_net_id);
 185
 186        return tcf_hash_search(tn, a, index);
 187}
 188
 189static struct tc_action_ops act_simp_ops = {
 190        .kind           =       "simple",
 191        .type           =       TCA_ACT_SIMP,
 192        .owner          =       THIS_MODULE,
 193        .act            =       tcf_simp,
 194        .dump           =       tcf_simp_dump,
 195        .cleanup        =       tcf_simp_release,
 196        .init           =       tcf_simp_init,
 197        .walk           =       tcf_simp_walker,
 198        .lookup         =       tcf_simp_search,
 199};
 200
 201static __net_init int simp_init_net(struct net *net)
 202{
 203        struct tc_action_net *tn = net_generic(net, simp_net_id);
 204
 205        return tc_action_net_init(tn, &act_simp_ops, SIMP_TAB_MASK);
 206}
 207
 208static void __net_exit simp_exit_net(struct net *net)
 209{
 210        struct tc_action_net *tn = net_generic(net, simp_net_id);
 211
 212        tc_action_net_exit(tn);
 213}
 214
 215static struct pernet_operations simp_net_ops = {
 216        .init = simp_init_net,
 217        .exit = simp_exit_net,
 218        .id   = &simp_net_id,
 219        .size = sizeof(struct tc_action_net),
 220};
 221
 222MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 223MODULE_DESCRIPTION("Simple example action");
 224MODULE_LICENSE("GPL");
 225
 226static int __init simp_init_module(void)
 227{
 228        int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 229        if (!ret)
 230                pr_info("Simple TC action Loaded\n");
 231        return ret;
 232}
 233
 234static void __exit simp_cleanup_module(void)
 235{
 236        tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 237}
 238
 239module_init(simp_init_module);
 240module_exit(simp_cleanup_module);
 241