net/sched/act_gact.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * net/sched/act_gact.c         Generic actions
   4  *
   5  * copyright    Jamal Hadi Salim (2002-4)
   6  */
   7
   8 #include <linux/types.h>
   9 #include <linux/kernel.h>
  10 #include <linux/string.h>
  11 #include <linux/errno.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/rtnetlink.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <net/netlink.h>
  17 #include <net/pkt_sched.h>
  18 #include <net/pkt_cls.h>
  19 #include <linux/tc_act/tc_gact.h>
  20 #include <net/tc_act/tc_gact.h>
  21
  22 static unsigned int gact_net_id;
  23 static struct tc_action_ops act_gact_ops;
  24
  25 #ifdef CONFIG_GACT_PROB
  26 static int gact_net_rand(struct tcf_gact *gact)
  27 {
  28         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  29         if (prandom_u32() % gact->tcfg_pval)
  30                 return gact->tcf_action;
  31         return gact->tcfg_paction;
  32 }
  33
  34 static int gact_determ(struct tcf_gact *gact)
  35 {
  36         u32 pack = atomic_inc_return(&gact->packets);
  37
  38         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  39         if (pack % gact->tcfg_pval)
  40                 return gact->tcf_action;
  41         return gact->tcfg_paction;
  42 }
  43
  44 typedef int (*g_rand)(struct tcf_gact *gact);
  45 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  46 #endif /* CONFIG_GACT_PROB */
  47
  48 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  49         [TCA_GACT_PARMS]        = { .len = sizeof(struct tc_gact) },
  50         [TCA_GACT_PROB]         = { .len = sizeof(struct tc_gact_p) },
  51 };
  52
  53 static int tcf_gact_init(struct net *net, struct nlattr *nla,
  54                          struct nlattr *est, struct tc_action **a,
  55                          int ovr, int bind, bool rtnl_held,
  56                          struct tcf_proto *tp, struct netlink_ext_ack *extack)
  57 {
  58         struct tc_action_net *tn = net_generic(net, gact_net_id);
  59         struct nlattr *tb[TCA_GACT_MAX + 1];
  60         struct tcf_chain *goto_ch = NULL;
  61         struct tc_gact *parm;
  62         struct tcf_gact *gact;
  63         int ret = 0;
  64         int err;
  65 #ifdef CONFIG_GACT_PROB
  66         struct tc_gact_p *p_parm = NULL;
  67 #endif
  68
  69         if (nla == NULL)
  70                 return -EINVAL;
  71
  72         err = nla_parse_nested_deprecated(tb, TCA_GACT_MAX, nla, gact_policy,
  73                                           NULL);
  74         if (err < 0)
  75                 return err;
  76
  77         if (tb[TCA_GACT_PARMS] == NULL)
  78                 return -EINVAL;
  79         parm = nla_data(tb[TCA_GACT_PARMS]);
  80
  81 #ifndef CONFIG_GACT_PROB
  82         if (tb[TCA_GACT_PROB] != NULL)
  83                 return -EOPNOTSUPP;
  84 #else
  85         if (tb[TCA_GACT_PROB]) {
  86                 p_parm = nla_data(tb[TCA_GACT_PROB]);
  87                 if (p_parm->ptype >= MAX_RAND)
  88                         return -EINVAL;
  89                 if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
  90                         NL_SET_ERR_MSG(extack,
  91                                        "goto chain not allowed on fallback");
  92                         return -EINVAL;
  93                 }
  94         }
  95 #endif
  96
  97         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
  98         if (!err) {
  99                 ret = tcf_idr_create(tn, parm->index, est, a,
 100                                      &act_gact_ops, bind, true);
 101                 if (ret) {
 102                         tcf_idr_cleanup(tn, parm->index);
 103                         return ret;
 104                 }
 105                 ret = ACT_P_CREATED;
 106         } else if (err > 0) {
 107                 if (bind)/* dont override defaults */
 108                         return 0;
 109                 if (!ovr) {
 110                         tcf_idr_release(*a, bind);
 111                         return -EEXIST;
 112                 }
 113         } else {
 114                 return err;
 115         }
 116
 117         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 118         if (err < 0)
 119                 goto release_idr;
 120         gact = to_gact(*a);
 121
 122         spin_lock_bh(&gact->tcf_lock);
 123         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 124 #ifdef CONFIG_GACT_PROB
 125         if (p_parm) {
 126                 gact->tcfg_paction = p_parm->paction;
 127                 gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
 128                 /* Make sure tcfg_pval is written before tcfg_ptype
 129                  * coupled with smp_rmb() in gact_net_rand() & gact_determ()
 130                  */
 131                 smp_wmb();
 132                 gact->tcfg_ptype   = p_parm->ptype;
 133         }
 134 #endif
 135         spin_unlock_bh(&gact->tcf_lock);
 136
 137         if (goto_ch)
 138                 tcf_chain_put_by_act(goto_ch);
 139
 140         if (ret == ACT_P_CREATED)
 141                 tcf_idr_insert(tn, *a);
 142         return ret;
 143 release_idr:
 144         tcf_idr_release(*a, bind);
 145         return err;
 146 }
 147
 148 static int tcf_gact_act(struct sk_buff *skb, const struct tc_action *a,
 149                         struct tcf_result *res)
 150 {
 151         struct tcf_gact *gact = to_gact(a);
 152         int action = READ_ONCE(gact->tcf_action);
 153
 154 #ifdef CONFIG_GACT_PROB
 155         {
 156         u32 ptype = READ_ONCE(gact->tcfg_ptype);
 157
 158         if (ptype)
 159                 action = gact_rand[ptype](gact);
 160         }
 161 #endif
 162         bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
 163         if (action == TC_ACT_SHOT)
 164                 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
 165
 166         tcf_lastuse_update(&gact->tcf_tm);
 167
 168         return action;
 169 }
 170
 171 static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u32 packets,
 172                                   u64 lastuse, bool hw)
 173 {
 174         struct tcf_gact *gact = to_gact(a);
 175         int action = READ_ONCE(gact->tcf_action);
 176         struct tcf_t *tm = &gact->tcf_tm;
 177
 178         _bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), bytes,
 179                            packets);
 180         if (action == TC_ACT_SHOT)
 181                 this_cpu_ptr(gact->common.cpu_qstats)->drops += packets;
 182
 183         if (hw)
 184                 _bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats_hw),
 185                                    bytes, packets);
 186
 187         tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 188 }
 189
 190 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 191                          int bind, int ref)
 192 {
 193         unsigned char *b = skb_tail_pointer(skb);
 194         struct tcf_gact *gact = to_gact(a);
 195         struct tc_gact opt = {
 196                 .index   = gact->tcf_index,
 197                 .refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
 198                 .bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
 199         };
 200         struct tcf_t t;
 201
 202         spin_lock_bh(&gact->tcf_lock);
 203         opt.action = gact->tcf_action;
 204         if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 205                 goto nla_put_failure;
 206 #ifdef CONFIG_GACT_PROB
 207         if (gact->tcfg_ptype) {
 208                 struct tc_gact_p p_opt = {
 209                         .paction = gact->tcfg_paction,
 210                         .pval    = gact->tcfg_pval,
 211                         .ptype   = gact->tcfg_ptype,
 212                 };
 213
 214                 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 215                         goto nla_put_failure;
 216         }
 217 #endif
 218         tcf_tm_dump(&t, &gact->tcf_tm);
 219         if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 220                 goto nla_put_failure;
 221         spin_unlock_bh(&gact->tcf_lock);
 222
 223         return skb->len;
 224
 225 nla_put_failure:
 226         spin_unlock_bh(&gact->tcf_lock);
 227         nlmsg_trim(skb, b);
 228         return -1;
 229 }
 230
 231 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
 232                            struct netlink_callback *cb, int type,
 233                            const struct tc_action_ops *ops,
 234                            struct netlink_ext_ack *extack)
 235 {
 236         struct tc_action_net *tn = net_generic(net, gact_net_id);
 237
 238         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 239 }
 240
 241 static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
 242 {
 243         struct tc_action_net *tn = net_generic(net, gact_net_id);
 244
 245         return tcf_idr_search(tn, a, index);
 246 }
 247
 248 static size_t tcf_gact_get_fill_size(const struct tc_action *act)
 249 {
 250         size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
 251
 252 #ifdef CONFIG_GACT_PROB
 253         if (to_gact(act)->tcfg_ptype)
 254                 /* TCA_GACT_PROB */
 255                 sz += nla_total_size(sizeof(struct tc_gact_p));
 256 #endif
 257
 258         return sz;
 259 }
 260
 261 static struct tc_action_ops act_gact_ops = {
 262         .kind           =       "gact",
 263         .id             =       TCA_ID_GACT,
 264         .owner          =       THIS_MODULE,
 265         .act            =       tcf_gact_act,
 266         .stats_update   =       tcf_gact_stats_update,
 267         .dump           =       tcf_gact_dump,
 268         .init           =       tcf_gact_init,
 269         .walk           =       tcf_gact_walker,
 270         .lookup         =       tcf_gact_search,
 271         .get_fill_size  =       tcf_gact_get_fill_size,
 272         .size           =       sizeof(struct tcf_gact),
 273 };
 274
 275 static __net_init int gact_init_net(struct net *net)
 276 {
 277         struct tc_action_net *tn = net_generic(net, gact_net_id);
 278
 279         return tc_action_net_init(tn, &act_gact_ops);
 280 }
 281
 282 static void __net_exit gact_exit_net(struct list_head *net_list)
 283 {
 284         tc_action_net_exit(net_list, gact_net_id);
 285 }
 286
 287 static struct pernet_operations gact_net_ops = {
 288         .init = gact_init_net,
 289         .exit_batch = gact_exit_net,
 290         .id   = &gact_net_id,
 291         .size = sizeof(struct tc_action_net),
 292 };
 293
 294 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 295 MODULE_DESCRIPTION("Generic Classifier actions");
 296 MODULE_LICENSE("GPL");
 297
 298 static int __init gact_init_module(void)
 299 {
 300 #ifdef CONFIG_GACT_PROB
 301         pr_info("GACT probability on\n");
 302 #else
 303         pr_info("GACT probability NOT on\n");
 304 #endif
 305
 306         return tcf_register_action(&act_gact_ops, &gact_net_ops);
 307 }
 308
 309 static void __exit gact_cleanup_module(void)
 310 {
 311         tcf_unregister_action(&act_gact_ops, &gact_net_ops);
 312 }
 313
 314 module_init(gact_init_module);
 315 module_exit(gact_cleanup_module);