linux/net/sched/act_gact.c
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   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
  22static unsigned int gact_net_id;
  23static struct tc_action_ops act_gact_ops;
  24
  25#ifdef CONFIG_GACT_PROB
  26static 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
  34static 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
  44typedef int (*g_rand)(struct tcf_gact *gact);
  45static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  46#endif /* CONFIG_GACT_PROB */
  47
  48static 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
  53static int tcf_gact_init(struct net *net, struct nlattr *nla,
  54                         struct nlattr *est, struct tc_action **a,
  55                         struct tcf_proto *tp, u32 flags,
  56                         struct netlink_ext_ack *extack)
  57{
  58        struct tc_action_net *tn = net_generic(net, gact_net_id);
  59        bool bind = flags & TCA_ACT_FLAGS_BIND;
  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 (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 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        return ret;
 144release_idr:
 145        tcf_idr_release(*a, bind);
 146        return err;
 147}
 148
 149static int tcf_gact_act(struct sk_buff *skb, const struct tc_action *a,
 150                        struct tcf_result *res)
 151{
 152        struct tcf_gact *gact = to_gact(a);
 153        int action = READ_ONCE(gact->tcf_action);
 154
 155#ifdef CONFIG_GACT_PROB
 156        {
 157        u32 ptype = READ_ONCE(gact->tcfg_ptype);
 158
 159        if (ptype)
 160                action = gact_rand[ptype](gact);
 161        }
 162#endif
 163        tcf_action_update_bstats(&gact->common, skb);
 164        if (action == TC_ACT_SHOT)
 165                tcf_action_inc_drop_qstats(&gact->common);
 166
 167        tcf_lastuse_update(&gact->tcf_tm);
 168
 169        return action;
 170}
 171
 172static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u64 packets,
 173                                  u64 drops, u64 lastuse, bool hw)
 174{
 175        struct tcf_gact *gact = to_gact(a);
 176        int action = READ_ONCE(gact->tcf_action);
 177        struct tcf_t *tm = &gact->tcf_tm;
 178
 179        tcf_action_update_stats(a, bytes, packets,
 180                                action == TC_ACT_SHOT ? packets : drops, hw);
 181        tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 182}
 183
 184static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 185                         int bind, int ref)
 186{
 187        unsigned char *b = skb_tail_pointer(skb);
 188        struct tcf_gact *gact = to_gact(a);
 189        struct tc_gact opt = {
 190                .index   = gact->tcf_index,
 191                .refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
 192                .bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
 193        };
 194        struct tcf_t t;
 195
 196        spin_lock_bh(&gact->tcf_lock);
 197        opt.action = gact->tcf_action;
 198        if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 199                goto nla_put_failure;
 200#ifdef CONFIG_GACT_PROB
 201        if (gact->tcfg_ptype) {
 202                struct tc_gact_p p_opt = {
 203                        .paction = gact->tcfg_paction,
 204                        .pval    = gact->tcfg_pval,
 205                        .ptype   = gact->tcfg_ptype,
 206                };
 207
 208                if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 209                        goto nla_put_failure;
 210        }
 211#endif
 212        tcf_tm_dump(&t, &gact->tcf_tm);
 213        if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 214                goto nla_put_failure;
 215        spin_unlock_bh(&gact->tcf_lock);
 216
 217        return skb->len;
 218
 219nla_put_failure:
 220        spin_unlock_bh(&gact->tcf_lock);
 221        nlmsg_trim(skb, b);
 222        return -1;
 223}
 224
 225static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
 226                           struct netlink_callback *cb, int type,
 227                           const struct tc_action_ops *ops,
 228                           struct netlink_ext_ack *extack)
 229{
 230        struct tc_action_net *tn = net_generic(net, gact_net_id);
 231
 232        return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 233}
 234
 235static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
 236{
 237        struct tc_action_net *tn = net_generic(net, gact_net_id);
 238
 239        return tcf_idr_search(tn, a, index);
 240}
 241
 242static size_t tcf_gact_get_fill_size(const struct tc_action *act)
 243{
 244        size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
 245
 246#ifdef CONFIG_GACT_PROB
 247        if (to_gact(act)->tcfg_ptype)
 248                /* TCA_GACT_PROB */
 249                sz += nla_total_size(sizeof(struct tc_gact_p));
 250#endif
 251
 252        return sz;
 253}
 254
 255static int tcf_gact_offload_act_setup(struct tc_action *act, void *entry_data,
 256                                      u32 *index_inc, bool bind,
 257                                      struct netlink_ext_ack *extack)
 258{
 259        if (bind) {
 260                struct flow_action_entry *entry = entry_data;
 261
 262                if (is_tcf_gact_ok(act)) {
 263                        entry->id = FLOW_ACTION_ACCEPT;
 264                } else if (is_tcf_gact_shot(act)) {
 265                        entry->id = FLOW_ACTION_DROP;
 266                } else if (is_tcf_gact_trap(act)) {
 267                        entry->id = FLOW_ACTION_TRAP;
 268                } else if (is_tcf_gact_goto_chain(act)) {
 269                        entry->id = FLOW_ACTION_GOTO;
 270                        entry->chain_index = tcf_gact_goto_chain_index(act);
 271                } else if (is_tcf_gact_continue(act)) {
 272                        NL_SET_ERR_MSG_MOD(extack, "Offload of \"continue\" action is not supported");
 273                        return -EOPNOTSUPP;
 274                } else if (is_tcf_gact_reclassify(act)) {
 275                        NL_SET_ERR_MSG_MOD(extack, "Offload of \"reclassify\" action is not supported");
 276                        return -EOPNOTSUPP;
 277                } else if (is_tcf_gact_pipe(act)) {
 278                        NL_SET_ERR_MSG_MOD(extack, "Offload of \"pipe\" action is not supported");
 279                        return -EOPNOTSUPP;
 280                } else {
 281                        NL_SET_ERR_MSG_MOD(extack, "Unsupported generic action offload");
 282                        return -EOPNOTSUPP;
 283                }
 284                *index_inc = 1;
 285        } else {
 286                struct flow_offload_action *fl_action = entry_data;
 287
 288                if (is_tcf_gact_ok(act))
 289                        fl_action->id = FLOW_ACTION_ACCEPT;
 290                else if (is_tcf_gact_shot(act))
 291                        fl_action->id = FLOW_ACTION_DROP;
 292                else if (is_tcf_gact_trap(act))
 293                        fl_action->id = FLOW_ACTION_TRAP;
 294                else if (is_tcf_gact_goto_chain(act))
 295                        fl_action->id = FLOW_ACTION_GOTO;
 296                else
 297                        return -EOPNOTSUPP;
 298        }
 299
 300        return 0;
 301}
 302
 303static struct tc_action_ops act_gact_ops = {
 304        .kind           =       "gact",
 305        .id             =       TCA_ID_GACT,
 306        .owner          =       THIS_MODULE,
 307        .act            =       tcf_gact_act,
 308        .stats_update   =       tcf_gact_stats_update,
 309        .dump           =       tcf_gact_dump,
 310        .init           =       tcf_gact_init,
 311        .walk           =       tcf_gact_walker,
 312        .lookup         =       tcf_gact_search,
 313        .get_fill_size  =       tcf_gact_get_fill_size,
 314        .offload_act_setup =    tcf_gact_offload_act_setup,
 315        .size           =       sizeof(struct tcf_gact),
 316};
 317
 318static __net_init int gact_init_net(struct net *net)
 319{
 320        struct tc_action_net *tn = net_generic(net, gact_net_id);
 321
 322        return tc_action_net_init(net, tn, &act_gact_ops);
 323}
 324
 325static void __net_exit gact_exit_net(struct list_head *net_list)
 326{
 327        tc_action_net_exit(net_list, gact_net_id);
 328}
 329
 330static struct pernet_operations gact_net_ops = {
 331        .init = gact_init_net,
 332        .exit_batch = gact_exit_net,
 333        .id   = &gact_net_id,
 334        .size = sizeof(struct tc_action_net),
 335};
 336
 337MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 338MODULE_DESCRIPTION("Generic Classifier actions");
 339MODULE_LICENSE("GPL");
 340
 341static int __init gact_init_module(void)
 342{
 343#ifdef CONFIG_GACT_PROB
 344        pr_info("GACT probability on\n");
 345#else
 346        pr_info("GACT probability NOT on\n");
 347#endif
 348
 349        return tcf_register_action(&act_gact_ops, &gact_net_ops);
 350}
 351
 352static void __exit gact_cleanup_module(void)
 353{
 354        tcf_unregister_action(&act_gact_ops, &gact_net_ops);
 355}
 356
 357module_init(gact_init_module);
 358module_exit(gact_cleanup_module);
 359