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