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