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_%llu\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_strscpy(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_strscpy(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, u32 flags,
  90                          struct netlink_ext_ack *extack)
  91 {
  92         struct tc_action_net *tn = net_generic(net, simp_net_id);
  93         struct nlattr *tb[TCA_DEF_MAX + 1];
  94         struct tcf_chain *goto_ch = NULL;
  95         struct tc_defact *parm;
  96         struct tcf_defact *d;
  97         bool exists = false;
  98         int ret = 0, err;
  99         u32 index;
 100
 101         if (nla == NULL)
 102                 return -EINVAL;
 103
 104         err = nla_parse_nested_deprecated(tb, TCA_DEF_MAX, nla, simple_policy,
 105                                           NULL);
 106         if (err < 0)
 107                 return err;
 108
 109         if (tb[TCA_DEF_PARMS] == NULL)
 110                 return -EINVAL;
 111
 112         parm = nla_data(tb[TCA_DEF_PARMS]);
 113         index = parm->index;
 114         err = tcf_idr_check_alloc(tn, &index, a, bind);
 115         if (err < 0)
 116                 return err;
 117         exists = err;
 118         if (exists && bind)
 119                 return 0;
 120
 121         if (tb[TCA_DEF_DATA] == NULL) {
 122                 if (exists)
 123                         tcf_idr_release(*a, bind);
 124                 else
 125                         tcf_idr_cleanup(tn, index);
 126                 return -EINVAL;
 127         }
 128
 129         if (!exists) {
 130                 ret = tcf_idr_create(tn, index, est, a,
 131                                      &act_simp_ops, bind, false, 0);
 132                 if (ret) {
 133                         tcf_idr_cleanup(tn, index);
 134                         return ret;
 135                 }
 136
 137                 d = to_defact(*a);
 138                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 139                                                extack);
 140                 if (err < 0)
 141                         goto release_idr;
 142
 143                 err = alloc_defdata(d, tb[TCA_DEF_DATA]);
 144                 if (err < 0)
 145                         goto put_chain;
 146
 147                 tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 148                 ret = ACT_P_CREATED;
 149         } else {
 150                 if (!ovr) {
 151                         err = -EEXIST;
 152                         goto release_idr;
 153                 }
 154
 155                 err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack);
 156                 if (err)
 157                         goto release_idr;
 158         }
 159
 160         return ret;
 161 put_chain:
 162         if (goto_ch)
 163                 tcf_chain_put_by_act(goto_ch);
 164 release_idr:
 165         tcf_idr_release(*a, bind);
 166         return err;
 167 }
 168
 169 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 170                          int bind, int ref)
 171 {
 172         unsigned char *b = skb_tail_pointer(skb);
 173         struct tcf_defact *d = to_defact(a);
 174         struct tc_defact opt = {
 175                 .index   = d->tcf_index,
 176                 .refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 177                 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
 178         };
 179         struct tcf_t t;
 180
 181         spin_lock_bh(&d->tcf_lock);
 182         opt.action = d->tcf_action;
 183         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 184             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 185                 goto nla_put_failure;
 186
 187         tcf_tm_dump(&t, &d->tcf_tm);
 188         if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 189                 goto nla_put_failure;
 190         spin_unlock_bh(&d->tcf_lock);
 191
 192         return skb->len;
 193
 194 nla_put_failure:
 195         spin_unlock_bh(&d->tcf_lock);
 196         nlmsg_trim(skb, b);
 197         return -1;
 198 }
 199
 200 static int tcf_simp_walker(struct net *net, struct sk_buff *skb,
 201                            struct netlink_callback *cb, int type,
 202                            const struct tc_action_ops *ops,
 203                            struct netlink_ext_ack *extack)
 204 {
 205         struct tc_action_net *tn = net_generic(net, simp_net_id);
 206
 207         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 208 }
 209
 210 static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index)
 211 {
 212         struct tc_action_net *tn = net_generic(net, simp_net_id);
 213
 214         return tcf_idr_search(tn, a, index);
 215 }
 216
 217 static struct tc_action_ops act_simp_ops = {
 218         .kind           =       "simple",
 219         .id             =       TCA_ID_SIMP,
 220         .owner          =       THIS_MODULE,
 221         .act            =       tcf_simp_act,
 222         .dump           =       tcf_simp_dump,
 223         .cleanup        =       tcf_simp_release,
 224         .init           =       tcf_simp_init,
 225         .walk           =       tcf_simp_walker,
 226         .lookup         =       tcf_simp_search,
 227         .size           =       sizeof(struct tcf_defact),
 228 };
 229
 230 static __net_init int simp_init_net(struct net *net)
 231 {
 232         struct tc_action_net *tn = net_generic(net, simp_net_id);
 233
 234         return tc_action_net_init(net, tn, &act_simp_ops);
 235 }
 236
 237 static void __net_exit simp_exit_net(struct list_head *net_list)
 238 {
 239         tc_action_net_exit(net_list, simp_net_id);
 240 }
 241
 242 static struct pernet_operations simp_net_ops = {
 243         .init = simp_init_net,
 244         .exit_batch = simp_exit_net,
 245         .id   = &simp_net_id,
 246         .size = sizeof(struct tc_action_net),
 247 };
 248
 249 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 250 MODULE_DESCRIPTION("Simple example action");
 251 MODULE_LICENSE("GPL");
 252
 253 static int __init simp_init_module(void)
 254 {
 255         int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 256         if (!ret)
 257                 pr_info("Simple TC action Loaded\n");
 258         return ret;
 259 }
 260
 261 static void __exit simp_cleanup_module(void)
 262 {
 263         tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 264 }
 265
 266 module_init(simp_init_module);
 267 module_exit(simp_cleanup_module);