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