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 static unsigned int simp_net_id;
  28 static struct tc_action_ops act_simp_ops;
  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 = to_defact(a);
  35
  36         spin_lock(&d->tcf_lock);
  37         tcf_lastuse_update(&d->tcf_tm);
  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, const struct nlattr *defdata)
  57 {
  58         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  59         if (unlikely(!d->tcfd_defdata))
  60                 return -ENOMEM;
  61         nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  62         return 0;
  63 }
  64
  65 static void reset_policy(struct tcf_defact *d, const struct nlattr *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         nla_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 tc_action_net *tn = net_generic(net, simp_net_id);
  85         struct nlattr *tb[TCA_DEF_MAX + 1];
  86         struct tc_defact *parm;
  87         struct tcf_defact *d;
  88         bool exists = false;
  89         int ret = 0, err;
  90
  91         if (nla == NULL)
  92                 return -EINVAL;
  93
  94         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy, NULL);
  95         if (err < 0)
  96                 return err;
  97
  98         if (tb[TCA_DEF_PARMS] == NULL)
  99                 return -EINVAL;
 100
 101         parm = nla_data(tb[TCA_DEF_PARMS]);
 102         exists = tcf_idr_check(tn, parm->index, a, bind);
 103         if (exists && bind)
 104                 return 0;
 105
 106         if (tb[TCA_DEF_DATA] == NULL) {
 107                 if (exists)
 108                         tcf_idr_release(*a, bind);
 109                 return -EINVAL;
 110         }
 111
 112         if (!exists) {
 113                 ret = tcf_idr_create(tn, parm->index, est, a,
 114                                      &act_simp_ops, bind, false);
 115                 if (ret)
 116                         return ret;
 117
 118                 d = to_defact(*a);
 119                 ret = alloc_defdata(d, tb[TCA_DEF_DATA]);
 120                 if (ret < 0) {
 121                         tcf_idr_release(*a, bind);
 122                         return ret;
 123                 }
 124                 d->tcf_action = parm->action;
 125                 ret = ACT_P_CREATED;
 126         } else {
 127                 d = to_defact(*a);
 128
 129                 tcf_idr_release(*a, bind);
 130                 if (!ovr)
 131                         return -EEXIST;
 132
 133                 reset_policy(d, tb[TCA_DEF_DATA], parm);
 134         }
 135
 136         if (ret == ACT_P_CREATED)
 137                 tcf_idr_insert(tn, *a);
 138         return ret;
 139 }
 140
 141 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 142                          int bind, int ref)
 143 {
 144         unsigned char *b = skb_tail_pointer(skb);
 145         struct tcf_defact *d = to_defact(a);
 146         struct tc_defact opt = {
 147                 .index   = d->tcf_index,
 148                 .refcnt  = d->tcf_refcnt - ref,
 149                 .bindcnt = d->tcf_bindcnt - bind,
 150                 .action  = d->tcf_action,
 151         };
 152         struct tcf_t t;
 153
 154         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 155             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 156                 goto nla_put_failure;
 157
 158         tcf_tm_dump(&t, &d->tcf_tm);
 159         if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 160                 goto nla_put_failure;
 161         return skb->len;
 162
 163 nla_put_failure:
 164         nlmsg_trim(skb, b);
 165         return -1;
 166 }
 167
 168 static int tcf_simp_walker(struct net *net, struct sk_buff *skb,
 169                            struct netlink_callback *cb, int type,
 170                            const struct tc_action_ops *ops)
 171 {
 172         struct tc_action_net *tn = net_generic(net, simp_net_id);
 173
 174         return tcf_generic_walker(tn, skb, cb, type, ops);
 175 }
 176
 177 static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index)
 178 {
 179         struct tc_action_net *tn = net_generic(net, simp_net_id);
 180
 181         return tcf_idr_search(tn, a, index);
 182 }
 183
 184 static struct tc_action_ops act_simp_ops = {
 185         .kind           =       "simple",
 186         .type           =       TCA_ACT_SIMP,
 187         .owner          =       THIS_MODULE,
 188         .act            =       tcf_simp,
 189         .dump           =       tcf_simp_dump,
 190         .cleanup        =       tcf_simp_release,
 191         .init           =       tcf_simp_init,
 192         .walk           =       tcf_simp_walker,
 193         .lookup         =       tcf_simp_search,
 194         .size           =       sizeof(struct tcf_defact),
 195 };
 196
 197 static __net_init int simp_init_net(struct net *net)
 198 {
 199         struct tc_action_net *tn = net_generic(net, simp_net_id);
 200
 201         return tc_action_net_init(net, tn, &act_simp_ops);
 202 }
 203
 204 static void __net_exit simp_exit_net(struct net *net)
 205 {
 206         struct tc_action_net *tn = net_generic(net, simp_net_id);
 207
 208         tc_action_net_exit(tn);
 209 }
 210
 211 static struct pernet_operations simp_net_ops = {
 212         .init = simp_init_net,
 213         .exit = simp_exit_net,
 214         .id   = &simp_net_id,
 215         .size = sizeof(struct tc_action_net),
 216 };
 217
 218 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 219 MODULE_DESCRIPTION("Simple example action");
 220 MODULE_LICENSE("GPL");
 221
 222 static int __init simp_init_module(void)
 223 {
 224         int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 225         if (!ret)
 226                 pr_info("Simple TC action Loaded\n");
 227         return ret;
 228 }
 229
 230 static void __exit simp_cleanup_module(void)
 231 {
 232         tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 233 }
 234
 235 module_init(simp_init_module);
 236 module_exit(simp_cleanup_module);