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 #include <net/tc_wrapper.h>
  18
  19 #include <linux/tc_act/tc_defact.h>
  20 #include <net/tc_act/tc_defact.h>
  21
  22 static struct tc_action_ops act_simp_ops;
  23
  24 #define SIMP_MAX_DATA   32
  25 TC_INDIRECT_SCOPE int tcf_simp_act(struct sk_buff *skb,
  26                                    const struct tc_action *a,
  27                                    struct tcf_result *res)
  28 {
  29         struct tcf_defact *d = to_defact(a);
  30
  31         spin_lock(&d->tcf_lock);
  32         tcf_lastuse_update(&d->tcf_tm);
  33         bstats_update(&d->tcf_bstats, skb);
  34
  35         /* print policy string followed by _ then packet count
  36          * Example if this was the 3rd packet and the string was "hello"
  37          * then it would look like "hello_3" (without quotes)
  38          */
  39         pr_info("simple: %s_%llu\n",
  40                 (char *)d->tcfd_defdata,
  41                 u64_stats_read(&d->tcf_bstats.packets));
  42         spin_unlock(&d->tcf_lock);
  43         return d->tcf_action;
  44 }
  45
  46 static void tcf_simp_release(struct tc_action *a)
  47 {
  48         struct tcf_defact *d = to_defact(a);
  49         kfree(d->tcfd_defdata);
  50 }
  51
  52 static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata)
  53 {
  54         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  55         if (unlikely(!d->tcfd_defdata))
  56                 return -ENOMEM;
  57         nla_strscpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  58         return 0;
  59 }
  60
  61 static int reset_policy(struct tc_action *a, const struct nlattr *defdata,
  62                         struct tc_defact *p, struct tcf_proto *tp,
  63                         struct netlink_ext_ack *extack)
  64 {
  65         struct tcf_chain *goto_ch = NULL;
  66         struct tcf_defact *d;
  67         int err;
  68
  69         err = tcf_action_check_ctrlact(p->action, tp, &goto_ch, extack);
  70         if (err < 0)
  71                 return err;
  72         d = to_defact(a);
  73         spin_lock_bh(&d->tcf_lock);
  74         goto_ch = tcf_action_set_ctrlact(a, p->action, goto_ch);
  75         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  76         nla_strscpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  77         spin_unlock_bh(&d->tcf_lock);
  78         if (goto_ch)
  79                 tcf_chain_put_by_act(goto_ch);
  80         return 0;
  81 }
  82
  83 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  84         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  85         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  86 };
  87
  88 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  89                          struct nlattr *est, struct tc_action **a,
  90                          struct tcf_proto *tp, u32 flags,
  91                          struct netlink_ext_ack *extack)
  92 {
  93         struct tc_action_net *tn = net_generic(net, act_simp_ops.net_id);
  94         bool bind = flags & TCA_ACT_FLAGS_BIND;
  95         struct nlattr *tb[TCA_DEF_MAX + 1];
  96         struct tcf_chain *goto_ch = NULL;
  97         struct tc_defact *parm;
  98         struct tcf_defact *d;
  99         bool exists = false;
 100         int ret = 0, err;
 101         u32 index;
 102
 103         if (nla == NULL)
 104                 return -EINVAL;
 105
 106         err = nla_parse_nested_deprecated(tb, TCA_DEF_MAX, nla, simple_policy,
 107                                           NULL);
 108         if (err < 0)
 109                 return err;
 110
 111         if (tb[TCA_DEF_PARMS] == NULL)
 112                 return -EINVAL;
 113
 114         parm = nla_data(tb[TCA_DEF_PARMS]);
 115         index = parm->index;
 116         err = tcf_idr_check_alloc(tn, &index, a, bind);
 117         if (err < 0)
 118                 return err;
 119         exists = err;
 120         if (exists && bind)
 121                 return ACT_P_BOUND;
 122
 123         if (tb[TCA_DEF_DATA] == NULL) {
 124                 if (exists)
 125                         tcf_idr_release(*a, bind);
 126                 else
 127                         tcf_idr_cleanup(tn, index);
 128                 return -EINVAL;
 129         }
 130
 131         if (!exists) {
 132                 ret = tcf_idr_create(tn, index, est, a,
 133                                      &act_simp_ops, bind, false, flags);
 134                 if (ret) {
 135                         tcf_idr_cleanup(tn, index);
 136                         return ret;
 137                 }
 138
 139                 d = to_defact(*a);
 140                 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch,
 141                                                extack);
 142                 if (err < 0)
 143                         goto release_idr;
 144
 145                 err = alloc_defdata(d, tb[TCA_DEF_DATA]);
 146                 if (err < 0)
 147                         goto put_chain;
 148
 149                 tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 150                 ret = ACT_P_CREATED;
 151         } else {
 152                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 153                         err = -EEXIST;
 154                         goto release_idr;
 155                 }
 156
 157                 err = reset_policy(*a, tb[TCA_DEF_DATA], parm, tp, extack);
 158                 if (err)
 159                         goto release_idr;
 160         }
 161
 162         return ret;
 163 put_chain:
 164         if (goto_ch)
 165                 tcf_chain_put_by_act(goto_ch);
 166 release_idr:
 167         tcf_idr_release(*a, bind);
 168         return err;
 169 }
 170
 171 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 172                          int bind, int ref)
 173 {
 174         unsigned char *b = skb_tail_pointer(skb);
 175         struct tcf_defact *d = to_defact(a);
 176         struct tc_defact opt = {
 177                 .index   = d->tcf_index,
 178                 .refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 179                 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
 180         };
 181         struct tcf_t t;
 182
 183         spin_lock_bh(&d->tcf_lock);
 184         opt.action = d->tcf_action;
 185         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 186             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 187                 goto nla_put_failure;
 188
 189         tcf_tm_dump(&t, &d->tcf_tm);
 190         if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 191                 goto nla_put_failure;
 192         spin_unlock_bh(&d->tcf_lock);
 193
 194         return skb->len;
 195
 196 nla_put_failure:
 197         spin_unlock_bh(&d->tcf_lock);
 198         nlmsg_trim(skb, b);
 199         return -1;
 200 }
 201
 202 static struct tc_action_ops act_simp_ops = {
 203         .kind           =       "simple",
 204         .id             =       TCA_ID_SIMP,
 205         .owner          =       THIS_MODULE,
 206         .act            =       tcf_simp_act,
 207         .dump           =       tcf_simp_dump,
 208         .cleanup        =       tcf_simp_release,
 209         .init           =       tcf_simp_init,
 210         .size           =       sizeof(struct tcf_defact),
 211 };
 212 MODULE_ALIAS_NET_ACT("simple");
 213
 214 static __net_init int simp_init_net(struct net *net)
 215 {
 216         struct tc_action_net *tn = net_generic(net, act_simp_ops.net_id);
 217
 218         return tc_action_net_init(net, tn, &act_simp_ops);
 219 }
 220
 221 static void __net_exit simp_exit_net(struct list_head *net_list)
 222 {
 223         tc_action_net_exit(net_list, act_simp_ops.net_id);
 224 }
 225
 226 static struct pernet_operations simp_net_ops = {
 227         .init = simp_init_net,
 228         .exit_batch = simp_exit_net,
 229         .id   = &act_simp_ops.net_id,
 230         .size = sizeof(struct tc_action_net),
 231 };
 232
 233 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 234 MODULE_DESCRIPTION("Simple example action");
 235 MODULE_LICENSE("GPL");
 236
 237 static int __init simp_init_module(void)
 238 {
 239         int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 240         if (!ret)
 241                 pr_info("Simple TC action Loaded\n");
 242         return ret;
 243 }
 244
 245 static void __exit simp_cleanup_module(void)
 246 {
 247         tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 248 }
 249
 250 module_init(simp_init_module);
 251 module_exit(simp_cleanup_module);