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