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/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
  27 static struct tcf_common *tcf_simp_ht[SIMP_TAB_MASK + 1];
  28 static u32 simp_idx_gen;
  29 static DEFINE_RWLOCK(simp_lock);
  30
  31 static 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
  38 static 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 += skb->len;
  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
  57 static 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
  73 static 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
  82 static 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
  92 static 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
  97 static 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 (unlikely(!pc))
 128                         return -ENOMEM;
 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
 152 static 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
 161 static 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
 181 nla_put_failure:
 182         nlmsg_trim(skb, b);
 183         return -1;
 184 }
 185
 186 static 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
 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 ret = tcf_register_action(&act_simp_ops);
 206         if (!ret)
 207                 printk("Simple TC action Loaded\n");
 208         return ret;
 209 }
 210
 211 static void __exit simp_cleanup_module(void)
 212 {
 213         tcf_unregister_action(&act_simp_ops);
 214 }
 215
 216 module_init(simp_init_module);
 217 module_exit(simp_cleanup_module);