net/sched/act_simple.c

   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
  28 static u32 simp_idx_gen;
  29 static struct tcf_hashinfo simp_hash_info;
  30
  31 #define SIMP_MAX_DATA   32
  32 static 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
  51 static int tcf_simp_release(struct tcf_defact *d, int bind)
  52 {
  53         int ret = 0;
  54         if (d) {
  55                 if (bind)
  56                         d->tcf_bindcnt--;
  57                 d->tcf_refcnt--;
  58                 if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
  59                         kfree(d->tcfd_defdata);
  60                         tcf_hash_destroy(&d->common, &simp_hash_info);
  61                         ret = 1;
  62                 }
  63         }
  64         return ret;
  65 }
  66
  67 static int alloc_defdata(struct tcf_defact *d, char *defdata)
  68 {
  69         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  70         if (unlikely(!d->tcfd_defdata))
  71                 return -ENOMEM;
  72         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  73         return 0;
  74 }
  75
  76 static void reset_policy(struct tcf_defact *d, char *defdata,
  77                          struct tc_defact *p)
  78 {
  79         spin_lock_bh(&d->tcf_lock);
  80         d->tcf_action = p->action;
  81         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  82         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  83         spin_unlock_bh(&d->tcf_lock);
  84 }
  85
  86 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  87         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  88         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  89 };
  90
  91 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  92                          struct nlattr *est, struct tc_action *a,
  93                          int ovr, int bind)
  94 {
  95         struct nlattr *tb[TCA_DEF_MAX + 1];
  96         struct tc_defact *parm;
  97         struct tcf_defact *d;
  98         struct tcf_common *pc;
  99         char *defdata;
 100         int ret = 0, err;
 101
 102         if (nla == NULL)
 103                 return -EINVAL;
 104
 105         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
 106         if (err < 0)
 107                 return err;
 108
 109         if (tb[TCA_DEF_PARMS] == NULL)
 110                 return -EINVAL;
 111
 112         if (tb[TCA_DEF_DATA] == NULL)
 113                 return -EINVAL;
 114
 115         parm = nla_data(tb[TCA_DEF_PARMS]);
 116         defdata = nla_data(tb[TCA_DEF_DATA]);
 117
 118         pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
 119         if (!pc) {
 120                 pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
 121                                      &simp_idx_gen, &simp_hash_info);
 122                 if (IS_ERR(pc))
 123                         return PTR_ERR(pc);
 124
 125                 d = to_defact(pc);
 126                 ret = alloc_defdata(d, defdata);
 127                 if (ret < 0) {
 128                         if (est)
 129                                 gen_kill_estimator(&pc->tcfc_bstats,
 130                                                    &pc->tcfc_rate_est);
 131                         kfree_rcu(pc, tcfc_rcu);
 132                         return ret;
 133                 }
 134                 d->tcf_action = parm->action;
 135                 ret = ACT_P_CREATED;
 136         } else {
 137                 d = to_defact(pc);
 138                 if (!ovr) {
 139                         tcf_simp_release(d, bind);
 140                         return -EEXIST;
 141                 }
 142                 reset_policy(d, defdata, parm);
 143         }
 144
 145         if (ret == ACT_P_CREATED)
 146                 tcf_hash_insert(pc, &simp_hash_info);
 147         return ret;
 148 }
 149
 150 static int tcf_simp_cleanup(struct tc_action *a, int bind)
 151 {
 152         struct tcf_defact *d = a->priv;
 153
 154         if (d)
 155                 return tcf_simp_release(d, bind);
 156         return 0;
 157 }
 158
 159 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 160                          int bind, int ref)
 161 {
 162         unsigned char *b = skb_tail_pointer(skb);
 163         struct tcf_defact *d = a->priv;
 164         struct tc_defact opt = {
 165                 .index   = d->tcf_index,
 166                 .refcnt  = d->tcf_refcnt - ref,
 167                 .bindcnt = d->tcf_bindcnt - bind,
 168                 .action  = d->tcf_action,
 169         };
 170         struct tcf_t t;
 171
 172         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 173             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 174                 goto nla_put_failure;
 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         if (nla_put(skb, TCA_DEF_TM, sizeof(t), &t))
 179                 goto nla_put_failure;
 180         return skb->len;
 181
 182 nla_put_failure:
 183         nlmsg_trim(skb, b);
 184         return -1;
 185 }
 186
 187 static struct tc_action_ops act_simp_ops = {
 188         .kind           =       "simple",
 189         .hinfo          =       &simp_hash_info,
 190         .type           =       TCA_ACT_SIMP,
 191         .capab          =       TCA_CAP_NONE,
 192         .owner          =       THIS_MODULE,
 193         .act            =       tcf_simp,
 194         .dump           =       tcf_simp_dump,
 195         .cleanup        =       tcf_simp_cleanup,
 196         .init           =       tcf_simp_init,
 197 };
 198
 199 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 200 MODULE_DESCRIPTION("Simple example action");
 201 MODULE_LICENSE("GPL");
 202
 203 static int __init simp_init_module(void)
 204 {
 205         int err, ret;
 206         err = tcf_hashinfo_init(&simp_hash_info, SIMP_TAB_MASK);
 207         if (err)
 208                 return err;
 209
 210         ret = tcf_register_action(&act_simp_ops);
 211         if (!ret)
 212                 pr_info("Simple TC action Loaded\n");
 213         else
 214                 tcf_hashinfo_destroy(&simp_hash_info);
 215
 216         return ret;
 217 }
 218
 219 static void __exit simp_cleanup_module(void)
 220 {
 221         tcf_hashinfo_destroy(&simp_hash_info);
 222         tcf_unregister_action(&act_simp_ops);
 223 }
 224
 225 module_init(simp_init_module);
 226 module_exit(simp_cleanup_module);