net/sched/act_simple.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/act_simple.c       Simple example of an action
   4  *
   5  * Authors:     Jamal Hadi Salim (2005-8)
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/init.h>
  11 #include <linux/kernel.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/rtnetlink.h>
  14 #include <net/netlink.h>
  15 #include <net/pkt_sched.h>
  16 #include <net/pkt_cls.h>
  17
  18 #include <linux/tc_act/tc_defact.h>
  19 #include <net/tc_act/tc_defact.h>
  20
  21 static unsigned int simp_net_id;
  22 static struct tc_action_ops act_simp_ops;
  23
  24 #define SIMP_MAX_DATA   32
  25 static int tcf_simp_act(struct sk_buff *skb, const struct tc_action *a,
  26                         struct tcf_result *res)
  27 {
  28         struct tcf_defact *d = to_defact(a);
  29
  30         spin_lock(&d->tcf_lock);
  31         tcf_lastuse_update(&d->tcf_tm);
  32         bstats_update(&d->tcf_bstats, skb);
  33
  34         /* print policy string followed by _ then packet count
  35          * Example if this was the 3rd packet and the string was "hello"
  36          * then it would look like "hello_3" (without quotes)
  37          */
  38         pr_info("simple: %s_%d\n",
  39                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  40         spin_unlock(&d->tcf_lock);
  41         return d->tcf_action;
  42 }
  43
  44 static void tcf_simp_release(struct tc_action *a)
  45 {
  46         struct tcf_defact *d = to_defact(a);
  47         kfree(d->tcfd_defdata);
  48 }
  49
  50 static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata)
  51 {
  52         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  53         if (unlikely(!d->tcfd_defdata))
  54                 return -ENOMEM;
  55         nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  56         return 0;
  57 }
  58
  59 static int reset_policy(struct tc_action *a, const struct nlattr *defdata,
  60                         struct tc_defact *p, struct tcf_proto *tp,
  61                         struct netlink_ext_ack *extack)
  62 {
  63         struct tcf_chain *goto_ch = NULL;
  64         struct tcf_defact *d;
  65         int err;
  66
  67         err = tcf_action_check_ctrlact(p->action, tp, &goto_ch, extack);
  68         if (err < 0)
  69                 return err;
  70         d = to_defact(a);
  71         spin_lock_bh(&d->tcf_lock);
  72         goto_ch = tcf_action_set_ctrlact(a, p->action, goto_ch);
  73         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  74         nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  75         spin_unlock_bh(&d->tcf_lock);
  76         if (goto_ch)
  77                 tcf_chain_put_by_act(goto_ch);
  78         return 0;
  79 }
  80
  81 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  82         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  83         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  84 };
  85
  86 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  87                          struct nlattr *est, struct tc_action **a,
  88                          int ovr, int bind, bool rtnl_held,
  89                          struct tcf_proto *tp, struct netlink_ext_ack *extack)
  90 {
  91         struct tc_action_net *tn = net_generic(net, simp_net_id);
  92         struct nlattr *tb[TCA_DEF_MAX + 1];
  93         struct tcf_chain *goto_ch = NULL;
  94         struct tc_defact *parm;
  95         struct tcf_defact *d;
  96         bool exists = false;
  97         int ret = 0, err;
  98         u32 index;
  99
 100         if (nla == NULL)
 101                 return -EINVAL;
 102
 103         err = nla_parse_nested_deprecated(tb, TCA_DEF_MAX, nla, simple_policy,
 104                                           NULL);
 105         if (err < 0)
 106                 return err;
 107
 108         if (tb[TCA_DEF_PARMS] == NULL)
 109                 return -EINVAL;
 110
 111         parm = nla_data(tb[TCA_DEF_PARMS]);
 112         index = parm->index;
 113         err = tcf_idr_check_alloc(tn, &index, a, bind);
 114         if (err < 0)
 115                 return err;
 116         exists = err;
 117         if (exists && bind)
 118                 return 0;
 119
 120         if (tb[TCA_DEF_DATA] == NULL) {
 121                 if (exists)
 122                         tcf_idr_release(*a, bind);
 123                 else
 124                         tcf_idr_cleanup(tn, index);
 125                 return -EINVAL;
 126         }
 127
 128         if (!exists) {
 129                 ret = tcf_idr_create(tn, index, est, a,
 130                                      &act_simp_ops, bind, false);
 131                 if (ret) {
 132                         tcf_idr_cleanup(tn, index);
 133                         return ret;
 134                 }
 135
 136                 d = to_defact(*a);
 137                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 138                                                extack);
 139                 if (err < 0)
 140                         goto release_idr;
 141
 142                 err = alloc_defdata(d, tb[TCA_DEF_DATA]);
 143                 if (err < 0)
 144                         goto put_chain;
 145
 146                 tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 147                 ret = ACT_P_CREATED;
 148         } else {
 149                 if (!ovr) {
 150                         err = -EEXIST;
 151                         goto release_idr;
 152                 }
 153
 154                 err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack);
 155                 if (err)
 156                         goto release_idr;
 157         }
 158
 159         if (ret == ACT_P_CREATED)
 160                 tcf_idr_insert(tn, *a);
 161         return ret;
 162 put_chain:
 163         if (goto_ch)
 164                 tcf_chain_put_by_act(goto_ch);
 165 release_idr:
 166         tcf_idr_release(*a, bind);
 167         return err;
 168 }
 169
 170 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 171                          int bind, int ref)
 172 {
 173         unsigned char *b = skb_tail_pointer(skb);
 174         struct tcf_defact *d = to_defact(a);
 175         struct tc_defact opt = {
 176                 .index   = d->tcf_index,
 177                 .refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 178                 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
 179         };
 180         struct tcf_t t;
 181
 182         spin_lock_bh(&d->tcf_lock);
 183         opt.action = d->tcf_action;
 184         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 185             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 186                 goto nla_put_failure;
 187
 188         tcf_tm_dump(&t, &d->tcf_tm);
 189         if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 190                 goto nla_put_failure;
 191         spin_unlock_bh(&d->tcf_lock);
 192
 193         return skb->len;
 194
 195 nla_put_failure:
 196         spin_unlock_bh(&d->tcf_lock);
 197         nlmsg_trim(skb, b);
 198         return -1;
 199 }
 200
 201 static int tcf_simp_walker(struct net *net, struct sk_buff *skb,
 202                            struct netlink_callback *cb, int type,
 203                            const struct tc_action_ops *ops,
 204                            struct netlink_ext_ack *extack)
 205 {
 206         struct tc_action_net *tn = net_generic(net, simp_net_id);
 207
 208         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 209 }
 210
 211 static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index)
 212 {
 213         struct tc_action_net *tn = net_generic(net, simp_net_id);
 214
 215         return tcf_idr_search(tn, a, index);
 216 }
 217
 218 static struct tc_action_ops act_simp_ops = {
 219         .kind           =       "simple",
 220         .id             =       TCA_ID_SIMP,
 221         .owner          =       THIS_MODULE,
 222         .act            =       tcf_simp_act,
 223         .dump           =       tcf_simp_dump,
 224         .cleanup        =       tcf_simp_release,
 225         .init           =       tcf_simp_init,
 226         .walk           =       tcf_simp_walker,
 227         .lookup         =       tcf_simp_search,
 228         .size           =       sizeof(struct tcf_defact),
 229 };
 230
 231 static __net_init int simp_init_net(struct net *net)
 232 {
 233         struct tc_action_net *tn = net_generic(net, simp_net_id);
 234
 235         return tc_action_net_init(net, tn, &act_simp_ops);
 236 }
 237
 238 static void __net_exit simp_exit_net(struct list_head *net_list)
 239 {
 240         tc_action_net_exit(net_list, simp_net_id);
 241 }
 242
 243 static struct pernet_operations simp_net_ops = {
 244         .init = simp_init_net,
 245         .exit_batch = simp_exit_net,
 246         .id   = &simp_net_id,
 247         .size = sizeof(struct tc_action_net),
 248 };
 249
 250 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 251 MODULE_DESCRIPTION("Simple example action");
 252 MODULE_LICENSE("GPL");
 253
 254 static int __init simp_init_module(void)
 255 {
 256         int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 257         if (!ret)
 258                 pr_info("Simple TC action Loaded\n");
 259         return ret;
 260 }
 261
 262 static void __exit simp_cleanup_module(void)
 263 {
 264         tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 265 }
 266
 267 module_init(simp_init_module);
 268 module_exit(simp_cleanup_module);