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 struct tcf_common *tcf_simp_ht[SIMP_TAB_MASK + 1];
  29 static u32 simp_idx_gen;
  30 static DEFINE_RWLOCK(simp_lock);
  31
  32 static struct tcf_hashinfo simp_hash_info = {
  33         .htab   =       tcf_simp_ht,
  34         .hmask  =       SIMP_TAB_MASK,
  35         .lock   =       &simp_lock,
  36 };
  37
  38 #define SIMP_MAX_DATA   32
  39 static int tcf_simp(struct sk_buff *skb, struct tc_action *a, struct tcf_result *res)
  40 {
  41         struct tcf_defact *d = a->priv;
  42
  43         spin_lock(&d->tcf_lock);
  44         d->tcf_tm.lastuse = jiffies;
  45         d->tcf_bstats.bytes += qdisc_pkt_len(skb);
  46         d->tcf_bstats.packets++;
  47
  48         /* print policy string followed by _ then packet count
  49          * Example if this was the 3rd packet and the string was "hello"
  50          * then it would look like "hello_3" (without quotes)
  51          **/
  52         pr_info("simple: %s_%d\n",
  53                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  54         spin_unlock(&d->tcf_lock);
  55         return d->tcf_action;
  56 }
  57
  58 static int tcf_simp_release(struct tcf_defact *d, int bind)
  59 {
  60         int ret = 0;
  61         if (d) {
  62                 if (bind)
  63                         d->tcf_bindcnt--;
  64                 d->tcf_refcnt--;
  65                 if (d->tcf_bindcnt <= 0 && d->tcf_refcnt <= 0) {
  66                         kfree(d->tcfd_defdata);
  67                         tcf_hash_destroy(&d->common, &simp_hash_info);
  68                         ret = 1;
  69                 }
  70         }
  71         return ret;
  72 }
  73
  74 static int alloc_defdata(struct tcf_defact *d, char *defdata)
  75 {
  76         d->tcfd_defdata = kstrndup(defdata, SIMP_MAX_DATA, GFP_KERNEL);
  77         if (unlikely(!d->tcfd_defdata))
  78                 return -ENOMEM;
  79
  80         return 0;
  81 }
  82
  83 static void reset_policy(struct tcf_defact *d, char *defdata,
  84                          struct tc_defact *p)
  85 {
  86         spin_lock_bh(&d->tcf_lock);
  87         d->tcf_action = p->action;
  88         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  89         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  90         spin_unlock_bh(&d->tcf_lock);
  91 }
  92
  93 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  94         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  95         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  96 };
  97
  98 static int tcf_simp_init(struct nlattr *nla, struct nlattr *est,
  99                          struct tc_action *a, int ovr, int bind)
 100 {
 101         struct nlattr *tb[TCA_DEF_MAX + 1];
 102         struct tc_defact *parm;
 103         struct tcf_defact *d;
 104         struct tcf_common *pc;
 105         char *defdata;
 106         int ret = 0, err;
 107
 108         if (nla == NULL)
 109                 return -EINVAL;
 110
 111         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
 112         if (err < 0)
 113                 return err;
 114
 115         if (tb[TCA_DEF_PARMS] == NULL)
 116                 return -EINVAL;
 117
 118         if (tb[TCA_DEF_DATA] == NULL)
 119                 return -EINVAL;
 120
 121         parm = nla_data(tb[TCA_DEF_PARMS]);
 122         defdata = nla_data(tb[TCA_DEF_DATA]);
 123
 124         pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);
 125         if (!pc) {
 126                 pc = tcf_hash_create(parm->index, est, a, sizeof(*d), bind,
 127                                      &simp_idx_gen, &simp_hash_info);
 128                 if (IS_ERR(pc))
 129                     return PTR_ERR(pc);
 130
 131                 d = to_defact(pc);
 132                 ret = alloc_defdata(d, defdata);
 133                 if (ret < 0) {
 134                         kfree(pc);
 135                         return ret;
 136                 }
 137                 d->tcf_action = parm->action;
 138                 ret = ACT_P_CREATED;
 139         } else {
 140                 d = to_defact(pc);
 141                 if (!ovr) {
 142                         tcf_simp_release(d, bind);
 143                         return -EEXIST;
 144                 }
 145                 reset_policy(d, defdata, parm);
 146         }
 147
 148         if (ret == ACT_P_CREATED)
 149                 tcf_hash_insert(pc, &simp_hash_info);
 150         return ret;
 151 }
 152
 153 static inline int tcf_simp_cleanup(struct tc_action *a, int bind)
 154 {
 155         struct tcf_defact *d = a->priv;
 156
 157         if (d)
 158                 return tcf_simp_release(d, bind);
 159         return 0;
 160 }
 161
 162 static inline int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 163                                 int bind, int ref)
 164 {
 165         unsigned char *b = skb_tail_pointer(skb);
 166         struct tcf_defact *d = a->priv;
 167         struct tc_defact opt;
 168         struct tcf_t t;
 169
 170         opt.index = d->tcf_index;
 171         opt.refcnt = d->tcf_refcnt - ref;
 172         opt.bindcnt = d->tcf_bindcnt - bind;
 173         opt.action = d->tcf_action;
 174         NLA_PUT(skb, TCA_DEF_PARMS, sizeof(opt), &opt);
 175         NLA_PUT_STRING(skb, TCA_DEF_DATA, d->tcfd_defdata);
 176         t.install = jiffies_to_clock_t(jiffies - d->tcf_tm.install);
 177         t.lastuse = jiffies_to_clock_t(jiffies - d->tcf_tm.lastuse);
 178         t.expires = jiffies_to_clock_t(d->tcf_tm.expires);
 179         NLA_PUT(skb, TCA_DEF_TM, sizeof(t), &t);
 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         .walk           =       tcf_generic_walker,
 198 };
 199
 200 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 201 MODULE_DESCRIPTION("Simple example action");
 202 MODULE_LICENSE("GPL");
 203
 204 static int __init simp_init_module(void)
 205 {
 206         int ret = tcf_register_action(&act_simp_ops);
 207         if (!ret)
 208                 pr_info("Simple TC action Loaded\n");
 209         return ret;
 210 }
 211
 212 static void __exit simp_cleanup_module(void)
 213 {
 214         tcf_unregister_action(&act_simp_ops);
 215 }
 216
 217 module_init(simp_init_module);
 218 module_exit(simp_cleanup_module);