net/sched/act_gact.c

   1 /*
   2  * net/sched/act_gact.c         Generic actions
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * copyright    Jamal Hadi Salim (2002-4)
  10  *
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/string.h>
  16 #include <linux/errno.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <net/pkt_cls.h>
  24 #include <linux/tc_act/tc_gact.h>
  25 #include <net/tc_act/tc_gact.h>
  26
  27 static unsigned int gact_net_id;
  28 static struct tc_action_ops act_gact_ops;
  29
  30 #ifdef CONFIG_GACT_PROB
  31 static int gact_net_rand(struct tcf_gact *gact)
  32 {
  33         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  34         if (prandom_u32() % gact->tcfg_pval)
  35                 return gact->tcf_action;
  36         return gact->tcfg_paction;
  37 }
  38
  39 static int gact_determ(struct tcf_gact *gact)
  40 {
  41         u32 pack = atomic_inc_return(&gact->packets);
  42
  43         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  44         if (pack % gact->tcfg_pval)
  45                 return gact->tcf_action;
  46         return gact->tcfg_paction;
  47 }
  48
  49 typedef int (*g_rand)(struct tcf_gact *gact);
  50 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  51 #endif /* CONFIG_GACT_PROB */
  52
  53 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  54         [TCA_GACT_PARMS]        = { .len = sizeof(struct tc_gact) },
  55         [TCA_GACT_PROB]         = { .len = sizeof(struct tc_gact_p) },
  56 };
  57
  58 static int tcf_gact_init(struct net *net, struct nlattr *nla,
  59                          struct nlattr *est, struct tc_action **a,
  60                          int ovr, int bind, bool rtnl_held,
  61                          struct tcf_proto *tp, struct netlink_ext_ack *extack)
  62 {
  63         struct tc_action_net *tn = net_generic(net, gact_net_id);
  64         struct nlattr *tb[TCA_GACT_MAX + 1];
  65         struct tcf_chain *goto_ch = NULL;
  66         struct tc_gact *parm;
  67         struct tcf_gact *gact;
  68         int ret = 0;
  69         int err;
  70 #ifdef CONFIG_GACT_PROB
  71         struct tc_gact_p *p_parm = NULL;
  72 #endif
  73
  74         if (nla == NULL)
  75                 return -EINVAL;
  76
  77         err = nla_parse_nested(tb, TCA_GACT_MAX, nla, gact_policy, NULL);
  78         if (err < 0)
  79                 return err;
  80
  81         if (tb[TCA_GACT_PARMS] == NULL)
  82                 return -EINVAL;
  83         parm = nla_data(tb[TCA_GACT_PARMS]);
  84
  85 #ifndef CONFIG_GACT_PROB
  86         if (tb[TCA_GACT_PROB] != NULL)
  87                 return -EOPNOTSUPP;
  88 #else
  89         if (tb[TCA_GACT_PROB]) {
  90                 p_parm = nla_data(tb[TCA_GACT_PROB]);
  91                 if (p_parm->ptype >= MAX_RAND)
  92                         return -EINVAL;
  93                 if (TC_ACT_EXT_CMP(p_parm->paction, TC_ACT_GOTO_CHAIN)) {
  94                         NL_SET_ERR_MSG(extack,
  95                                        "goto chain not allowed on fallback");
  96                         return -EINVAL;
  97                 }
  98         }
  99 #endif
 100
 101         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 102         if (!err) {
 103                 ret = tcf_idr_create(tn, parm->index, est, a,
 104                                      &act_gact_ops, bind, true);
 105                 if (ret) {
 106                         tcf_idr_cleanup(tn, parm->index);
 107                         return ret;
 108                 }
 109                 ret = ACT_P_CREATED;
 110         } else if (err > 0) {
 111                 if (bind)/* dont override defaults */
 112                         return 0;
 113                 if (!ovr) {
 114                         tcf_idr_release(*a, bind);
 115                         return -EEXIST;
 116                 }
 117         } else {
 118                 return err;
 119         }
 120
 121         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 122         if (err < 0)
 123                 goto release_idr;
 124         gact = to_gact(*a);
 125
 126         spin_lock_bh(&gact->tcf_lock);
 127         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 128 #ifdef CONFIG_GACT_PROB
 129         if (p_parm) {
 130                 gact->tcfg_paction = p_parm->paction;
 131                 gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
 132                 /* Make sure tcfg_pval is written before tcfg_ptype
 133                  * coupled with smp_rmb() in gact_net_rand() & gact_determ()
 134                  */
 135                 smp_wmb();
 136                 gact->tcfg_ptype   = p_parm->ptype;
 137         }
 138 #endif
 139         spin_unlock_bh(&gact->tcf_lock);
 140
 141         if (goto_ch)
 142                 tcf_chain_put_by_act(goto_ch);
 143
 144         if (ret == ACT_P_CREATED)
 145                 tcf_idr_insert(tn, *a);
 146         return ret;
 147 release_idr:
 148         tcf_idr_release(*a, bind);
 149         return err;
 150 }
 151
 152 static int tcf_gact_act(struct sk_buff *skb, const struct tc_action *a,
 153                         struct tcf_result *res)
 154 {
 155         struct tcf_gact *gact = to_gact(a);
 156         int action = READ_ONCE(gact->tcf_action);
 157
 158 #ifdef CONFIG_GACT_PROB
 159         {
 160         u32 ptype = READ_ONCE(gact->tcfg_ptype);
 161
 162         if (ptype)
 163                 action = gact_rand[ptype](gact);
 164         }
 165 #endif
 166         bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
 167         if (action == TC_ACT_SHOT)
 168                 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
 169
 170         tcf_lastuse_update(&gact->tcf_tm);
 171
 172         return action;
 173 }
 174
 175 static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u32 packets,
 176                                   u64 lastuse, bool hw)
 177 {
 178         struct tcf_gact *gact = to_gact(a);
 179         int action = READ_ONCE(gact->tcf_action);
 180         struct tcf_t *tm = &gact->tcf_tm;
 181
 182         _bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), bytes,
 183                            packets);
 184         if (action == TC_ACT_SHOT)
 185                 this_cpu_ptr(gact->common.cpu_qstats)->drops += packets;
 186
 187         if (hw)
 188                 _bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats_hw),
 189                                    bytes, packets);
 190
 191         tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 192 }
 193
 194 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 195                          int bind, int ref)
 196 {
 197         unsigned char *b = skb_tail_pointer(skb);
 198         struct tcf_gact *gact = to_gact(a);
 199         struct tc_gact opt = {
 200                 .index   = gact->tcf_index,
 201                 .refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
 202                 .bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
 203         };
 204         struct tcf_t t;
 205
 206         spin_lock_bh(&gact->tcf_lock);
 207         opt.action = gact->tcf_action;
 208         if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 209                 goto nla_put_failure;
 210 #ifdef CONFIG_GACT_PROB
 211         if (gact->tcfg_ptype) {
 212                 struct tc_gact_p p_opt = {
 213                         .paction = gact->tcfg_paction,
 214                         .pval    = gact->tcfg_pval,
 215                         .ptype   = gact->tcfg_ptype,
 216                 };
 217
 218                 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 219                         goto nla_put_failure;
 220         }
 221 #endif
 222         tcf_tm_dump(&t, &gact->tcf_tm);
 223         if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 224                 goto nla_put_failure;
 225         spin_unlock_bh(&gact->tcf_lock);
 226
 227         return skb->len;
 228
 229 nla_put_failure:
 230         spin_unlock_bh(&gact->tcf_lock);
 231         nlmsg_trim(skb, b);
 232         return -1;
 233 }
 234
 235 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
 236                            struct netlink_callback *cb, int type,
 237                            const struct tc_action_ops *ops,
 238                            struct netlink_ext_ack *extack)
 239 {
 240         struct tc_action_net *tn = net_generic(net, gact_net_id);
 241
 242         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 243 }
 244
 245 static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
 246 {
 247         struct tc_action_net *tn = net_generic(net, gact_net_id);
 248
 249         return tcf_idr_search(tn, a, index);
 250 }
 251
 252 static size_t tcf_gact_get_fill_size(const struct tc_action *act)
 253 {
 254         size_t sz = nla_total_size(sizeof(struct tc_gact)); /* TCA_GACT_PARMS */
 255
 256 #ifdef CONFIG_GACT_PROB
 257         if (to_gact(act)->tcfg_ptype)
 258                 /* TCA_GACT_PROB */
 259                 sz += nla_total_size(sizeof(struct tc_gact_p));
 260 #endif
 261
 262         return sz;
 263 }
 264
 265 static struct tc_action_ops act_gact_ops = {
 266         .kind           =       "gact",
 267         .id             =       TCA_ID_GACT,
 268         .owner          =       THIS_MODULE,
 269         .act            =       tcf_gact_act,
 270         .stats_update   =       tcf_gact_stats_update,
 271         .dump           =       tcf_gact_dump,
 272         .init           =       tcf_gact_init,
 273         .walk           =       tcf_gact_walker,
 274         .lookup         =       tcf_gact_search,
 275         .get_fill_size  =       tcf_gact_get_fill_size,
 276         .size           =       sizeof(struct tcf_gact),
 277 };
 278
 279 static __net_init int gact_init_net(struct net *net)
 280 {
 281         struct tc_action_net *tn = net_generic(net, gact_net_id);
 282
 283         return tc_action_net_init(tn, &act_gact_ops);
 284 }
 285
 286 static void __net_exit gact_exit_net(struct list_head *net_list)
 287 {
 288         tc_action_net_exit(net_list, gact_net_id);
 289 }
 290
 291 static struct pernet_operations gact_net_ops = {
 292         .init = gact_init_net,
 293         .exit_batch = gact_exit_net,
 294         .id   = &gact_net_id,
 295         .size = sizeof(struct tc_action_net),
 296 };
 297
 298 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 299 MODULE_DESCRIPTION("Generic Classifier actions");
 300 MODULE_LICENSE("GPL");
 301
 302 static int __init gact_init_module(void)
 303 {
 304 #ifdef CONFIG_GACT_PROB
 305         pr_info("GACT probability on\n");
 306 #else
 307         pr_info("GACT probability NOT on\n");
 308 #endif
 309
 310         return tcf_register_action(&act_gact_ops, &gact_net_ops);
 311 }
 312
 313 static void __exit gact_cleanup_module(void)
 314 {
 315         tcf_unregister_action(&act_gact_ops, &gact_net_ops);
 316 }
 317
 318 module_init(gact_init_module);
 319 module_exit(gact_cleanup_module);