net/sched/act_simple.c

   1 /*
   2  * net/sched/act_simple.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
  29 #define SIMP_MAX_DATA   32
  30 static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
  31                     struct tcf_result *res)
  32 {
  33         struct tcf_defact *d = a->priv;
  34
  35         spin_lock(&d->tcf_lock);
  36         d->tcf_tm.lastuse = jiffies;
  37         bstats_update(&d->tcf_bstats, skb);
  38
  39         /* print policy string followed by _ then packet count
  40          * Example if this was the 3rd packet and the string was "hello"
  41          * then it would look like "hello_3" (without quotes)
  42          */
  43         pr_info("simple: %s_%d\n",
  44                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  45         spin_unlock(&d->tcf_lock);
  46         return d->tcf_action;
  47 }
  48
  49 static void tcf_simp_release(struct tc_action *a, int bind)
  50 {
  51         struct tcf_defact *d = to_defact(a);
  52         kfree(d->tcfd_defdata);
  53 }
  54
  55 static int alloc_defdata(struct tcf_defact *d, char *defdata)
  56 {
  57         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  58         if (unlikely(!d->tcfd_defdata))
  59                 return -ENOMEM;
  60         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  61         return 0;
  62 }
  63
  64 static void reset_policy(struct tcf_defact *d, char *defdata,
  65                          struct tc_defact *p)
  66 {
  67         spin_lock_bh(&d->tcf_lock);
  68         d->tcf_action = p->action;
  69         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  70         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  71         spin_unlock_bh(&d->tcf_lock);
  72 }
  73
  74 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  75         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  76         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  77 };
  78
  79 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  80                          struct nlattr *est, struct tc_action *a,
  81                          int ovr, int bind)
  82 {
  83         struct nlattr *tb[TCA_DEF_MAX + 1];
  84         struct tc_defact *parm;
  85         struct tcf_defact *d;
  86         char *defdata;
  87         int ret = 0, err;
  88
  89         if (nla == NULL)
  90                 return -EINVAL;
  91
  92         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
  93         if (err < 0)
  94                 return err;
  95
  96         if (tb[TCA_DEF_PARMS] == NULL)
  97                 return -EINVAL;
  98
  99         if (tb[TCA_DEF_DATA] == NULL)
 100                 return -EINVAL;
 101
 102         parm = nla_data(tb[TCA_DEF_PARMS]);
 103         defdata = nla_data(tb[TCA_DEF_DATA]);
 104
 105         if (!tcf_hash_check(parm->index, a, bind)) {
 106                 ret = tcf_hash_create(parm->index, est, a, sizeof(*d),
 107                                       bind, false);
 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         .type           =       TCA_ACT_SIMP,
 167         .owner          =       THIS_MODULE,
 168         .act            =       tcf_simp,
 169         .dump           =       tcf_simp_dump,
 170         .cleanup        =       tcf_simp_release,
 171         .init           =       tcf_simp_init,
 172 };
 173
 174 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 175 MODULE_DESCRIPTION("Simple example action");
 176 MODULE_LICENSE("GPL");
 177
 178 static int __init simp_init_module(void)
 179 {
 180         int ret;
 181         ret = tcf_register_action(&act_simp_ops, SIMP_TAB_MASK);
 182         if (!ret)
 183                 pr_info("Simple TC action Loaded\n");
 184         return ret;
 185 }
 186
 187 static void __exit simp_cleanup_module(void)
 188 {
 189         tcf_unregister_action(&act_simp_ops);
 190 }
 191
 192 module_init(simp_init_module);
 193 module_exit(simp_cleanup_module);