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)
  60 {
  61         struct tc_action_net *tn = net_generic(net, gact_net_id);
  62         struct nlattr *tb[TCA_GACT_MAX + 1];
  63         struct tc_gact *parm;
  64         struct tcf_gact *gact;
  65         int ret = 0;
  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(tb, TCA_GACT_MAX, nla, gact_policy, 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
  82 #ifndef CONFIG_GACT_PROB
  83         if (tb[TCA_GACT_PROB] != NULL)
  84                 return -EOPNOTSUPP;
  85 #else
  86         if (tb[TCA_GACT_PROB]) {
  87                 p_parm = nla_data(tb[TCA_GACT_PROB]);
  88                 if (p_parm->ptype >= MAX_RAND)
  89                         return -EINVAL;
  90         }
  91 #endif
  92
  93         if (!tcf_idr_check(tn, parm->index, a, bind)) {
  94                 ret = tcf_idr_create(tn, parm->index, est, a,
  95                                      &act_gact_ops, bind, true);
  96                 if (ret)
  97                         return ret;
  98                 ret = ACT_P_CREATED;
  99         } else {
 100                 if (bind)/* dont override defaults */
 101                         return 0;
 102                 tcf_idr_release(*a, bind);
 103                 if (!ovr)
 104                         return -EEXIST;
 105         }
 106
 107         gact = to_gact(*a);
 108
 109         ASSERT_RTNL();
 110         gact->tcf_action = parm->action;
 111 #ifdef CONFIG_GACT_PROB
 112         if (p_parm) {
 113                 gact->tcfg_paction = p_parm->paction;
 114                 gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
 115                 /* Make sure tcfg_pval is written before tcfg_ptype
 116                  * coupled with smp_rmb() in gact_net_rand() & gact_determ()
 117                  */
 118                 smp_wmb();
 119                 gact->tcfg_ptype   = p_parm->ptype;
 120         }
 121 #endif
 122         if (ret == ACT_P_CREATED)
 123                 tcf_idr_insert(tn, *a);
 124         return ret;
 125 }
 126
 127 static int tcf_gact(struct sk_buff *skb, const struct tc_action *a,
 128                     struct tcf_result *res)
 129 {
 130         struct tcf_gact *gact = to_gact(a);
 131         int action = READ_ONCE(gact->tcf_action);
 132
 133 #ifdef CONFIG_GACT_PROB
 134         {
 135         u32 ptype = READ_ONCE(gact->tcfg_ptype);
 136
 137         if (ptype)
 138                 action = gact_rand[ptype](gact);
 139         }
 140 #endif
 141         bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
 142         if (action == TC_ACT_SHOT)
 143                 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
 144
 145         tcf_lastuse_update(&gact->tcf_tm);
 146
 147         return action;
 148 }
 149
 150 static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u32 packets,
 151                                   u64 lastuse)
 152 {
 153         struct tcf_gact *gact = to_gact(a);
 154         int action = READ_ONCE(gact->tcf_action);
 155         struct tcf_t *tm = &gact->tcf_tm;
 156
 157         _bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), bytes,
 158                            packets);
 159         if (action == TC_ACT_SHOT)
 160                 this_cpu_ptr(gact->common.cpu_qstats)->drops += packets;
 161
 162         tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 163 }
 164
 165 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 166                          int bind, int ref)
 167 {
 168         unsigned char *b = skb_tail_pointer(skb);
 169         struct tcf_gact *gact = to_gact(a);
 170         struct tc_gact opt = {
 171                 .index   = gact->tcf_index,
 172                 .refcnt  = gact->tcf_refcnt - ref,
 173                 .bindcnt = gact->tcf_bindcnt - bind,
 174                 .action  = gact->tcf_action,
 175         };
 176         struct tcf_t t;
 177
 178         if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 179                 goto nla_put_failure;
 180 #ifdef CONFIG_GACT_PROB
 181         if (gact->tcfg_ptype) {
 182                 struct tc_gact_p p_opt = {
 183                         .paction = gact->tcfg_paction,
 184                         .pval    = gact->tcfg_pval,
 185                         .ptype   = gact->tcfg_ptype,
 186                 };
 187
 188                 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 189                         goto nla_put_failure;
 190         }
 191 #endif
 192         tcf_tm_dump(&t, &gact->tcf_tm);
 193         if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 194                 goto nla_put_failure;
 195         return skb->len;
 196
 197 nla_put_failure:
 198         nlmsg_trim(skb, b);
 199         return -1;
 200 }
 201
 202 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
 203                            struct netlink_callback *cb, int type,
 204                            const struct tc_action_ops *ops)
 205 {
 206         struct tc_action_net *tn = net_generic(net, gact_net_id);
 207
 208         return tcf_generic_walker(tn, skb, cb, type, ops);
 209 }
 210
 211 static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
 212 {
 213         struct tc_action_net *tn = net_generic(net, gact_net_id);
 214
 215         return tcf_idr_search(tn, a, index);
 216 }
 217
 218 static struct tc_action_ops act_gact_ops = {
 219         .kind           =       "gact",
 220         .type           =       TCA_ACT_GACT,
 221         .owner          =       THIS_MODULE,
 222         .act            =       tcf_gact,
 223         .stats_update   =       tcf_gact_stats_update,
 224         .dump           =       tcf_gact_dump,
 225         .init           =       tcf_gact_init,
 226         .walk           =       tcf_gact_walker,
 227         .lookup         =       tcf_gact_search,
 228         .size           =       sizeof(struct tcf_gact),
 229 };
 230
 231 static __net_init int gact_init_net(struct net *net)
 232 {
 233         struct tc_action_net *tn = net_generic(net, gact_net_id);
 234
 235         return tc_action_net_init(tn, &act_gact_ops);
 236 }
 237
 238 static void __net_exit gact_exit_net(struct list_head *net_list)
 239 {
 240         tc_action_net_exit(net_list, gact_net_id);
 241 }
 242
 243 static struct pernet_operations gact_net_ops = {
 244         .init = gact_init_net,
 245         .exit_batch = gact_exit_net,
 246         .id   = &gact_net_id,
 247         .size = sizeof(struct tc_action_net),
 248 };
 249
 250 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 251 MODULE_DESCRIPTION("Generic Classifier actions");
 252 MODULE_LICENSE("GPL");
 253
 254 static int __init gact_init_module(void)
 255 {
 256 #ifdef CONFIG_GACT_PROB
 257         pr_info("GACT probability on\n");
 258 #else
 259         pr_info("GACT probability NOT on\n");
 260 #endif
 261
 262         return tcf_register_action(&act_gact_ops, &gact_net_ops);
 263 }
 264
 265 static void __exit gact_cleanup_module(void)
 266 {
 267         tcf_unregister_action(&act_gact_ops, &gact_net_ops);
 268 }
 269
 270 module_init(gact_init_module);
 271 module_exit(gact_cleanup_module);