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)
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/rtnetlink.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 static int tcf_simp(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
  38 {
  39         struct tcf_defact *d = a->priv;
  40
  41         spin_lock(&d->tcf_lock);
  42         d->tcf_tm.lastuse = jiffies;
  43         d->tcf_bstats.bytes += skb->len;
  44         d->tcf_bstats.packets++;
  45
  46         /* print policy string followed by _ then packet count
  47          * Example if this was the 3rd packet and the string was "hello"
  48          * then it would look like "hello_3" (without quotes)
  49          **/
  50         printk("simple: %s_%d\n",
  51                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  52         spin_unlock(&d->tcf_lock);
  53         return d->tcf_action;
  54 }
  55
  56 static int tcf_simp_release(struct tcf_defact *d, int bind)
  57 {
  58         int ret = 0;
  59         if (d) {
  60                 if (bind)
  61                         d->tcf_bindcnt--;
  62                 d->tcf_refcnt--;
  63                 if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
  64                         kfree(d->tcfd_defdata);
  65                         tcf_hash_destroy(&d->common, &simp_hash_info);
  66                         ret = 1;
  67                 }
  68         }
  69         return ret;
  70 }
  71
  72 static int alloc_defdata(struct tcf_defact *d, u32 datalen, void *defdata)
  73 {
  74         d->tcfd_defdata = kmemdup(defdata, datalen, GFP_KERNEL);
  75         if (unlikely(!d->tcfd_defdata))
  76                 return -ENOMEM;
  77         d->tcfd_datalen = datalen;
  78         return 0;
  79 }
  80
  81 static int realloc_defdata(struct tcf_defact *d, u32 datalen, void *defdata)
  82 {
  83         kfree(d->tcfd_defdata);
  84         return alloc_defdata(d, datalen, defdata);
  85 }
  86
  87 static int tcf_simp_init(struct rtattr *rta, struct rtattr *est,
  88                          struct tc_action *a, int ovr, int bind)
  89 {
  90         struct rtattr *tb[TCA_DEF_MAX];
  91         struct tc_defact *parm;
  92         struct tcf_defact *d;
  93         struct tcf_common *pc;
  94         void *defdata;
  95         u32 datalen = 0;
  96         int ret = 0;
  97
  98         if (rta == NULL || rtattr_parse_nested(tb, TCA_DEF_MAX, rta) < 0)
  99                 return -EINVAL;
 100
 101         if (tb[TCA_DEF_PARMS - 1] == NULL ||
 102             RTA_PAYLOAD(tb[TCA_DEF_PARMS - 1]) < sizeof(*parm))
 103                 return -EINVAL;
 104
 105         parm = RTA_DATA(tb[TCA_DEF_PARMS - 1]);
 106         defdata = RTA_DATA(tb[TCA_DEF_DATA - 1]);
 107         if (defdata == NULL)
 108                 return -EINVAL;
 109
 110         datalen = RTA_PAYLOAD(tb[TCA_DEF_DATA - 1]);
 111         if (datalen <= 0)
 112                 return -EINVAL;
 113
 114         pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
 115         if (!pc) {
 116                 pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
 117                                      &simp_idx_gen, &simp_hash_info);
 118                 if (unlikely(!pc))
 119                         return -ENOMEM;
 120
 121                 d = to_defact(pc);
 122                 ret = alloc_defdata(d, datalen, defdata);
 123                 if (ret < 0) {
 124                         kfree(pc);
 125                         return ret;
 126                 }
 127                 ret = ACT_P_CREATED;
 128         } else {
 129                 d = to_defact(pc);
 130                 if (!ovr) {
 131                         tcf_simp_release(d, bind);
 132                         return -EEXIST;
 133                 }
 134                 realloc_defdata(d, datalen, defdata);
 135         }
 136
 137         spin_lock_bh(&d->tcf_lock);
 138         d->tcf_action = parm->action;
 139         spin_unlock_bh(&d->tcf_lock);
 140
 141         if (ret == ACT_P_CREATED)
 142                 tcf_hash_insert(pc, &simp_hash_info);
 143         return ret;
 144 }
 145
 146 static inline int tcf_simp_cleanup(struct tc_action *a, int bind)
 147 {
 148         struct tcf_defact *d = a->priv;
 149
 150         if (d)
 151                 return tcf_simp_release(d, bind);
 152         return 0;
 153 }
 154
 155 static inline int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 156                                 int bind, int ref)
 157 {
 158         unsigned char *b = skb_tail_pointer(skb);
 159         struct tcf_defact *d = a->priv;
 160         struct tc_defact opt;
 161         struct tcf_t t;
 162
 163         opt.index = d->tcf_index;
 164         opt.refcnt = d->tcf_refcnt - ref;
 165         opt.bindcnt = d->tcf_bindcnt - bind;
 166         opt.action = d->tcf_action;
 167         RTA_PUT(skb, TCA_DEF_PARMS, sizeof(opt), &opt);
 168         RTA_PUT(skb, TCA_DEF_DATA, d->tcfd_datalen, d->tcfd_defdata);
 169         t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
 170         t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
 171         t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
 172         RTA_PUT(skb, TCA_DEF_TM, sizeof(t), &t);
 173         return skb->len;
 174
 175 rtattr_failure:
 176         skb_trim(skb, b - skb->data);
 177         return -1;
 178 }
 179
 180 static struct tc_action_ops act_simp_ops = {
 181         .kind           =       "simple",
 182         .hinfo          =       &simp_hash_info,
 183         .type           =       TCA_ACT_SIMP,
 184         .capab          =       TCA_CAP_NONE,
 185         .owner          =       THIS_MODULE,
 186         .act            =       tcf_simp,
 187         .dump           =       tcf_simp_dump,
 188         .cleanup        =       tcf_simp_cleanup,
 189         .init           =       tcf_simp_init,
 190         .walk           =       tcf_generic_walker,
 191 };
 192
 193 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 194 MODULE_DESCRIPTION("Simple example action");
 195 MODULE_LICENSE("GPL");
 196
 197 static int __init simp_init_module(void)
 198 {
 199         int ret = tcf_register_action(&act_simp_ops);
 200         if (!ret)
 201                 printk("Simple TC action Loaded\n");
 202         return ret;
 203 }
 204
 205 static void __exit simp_cleanup_module(void)
 206 {
 207         tcf_unregister_action(&act_simp_ops);
 208 }
 209
 210 module_init(simp_init_module);
 211 module_exit(simp_cleanup_module);