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