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 #define GACT_TAB_MASK   15
  27
  28 static int gact_net_id;
  29 static struct tc_action_ops act_gact_ops;
  30
  31 #ifdef CONFIG_GACT_PROB
  32 static int gact_net_rand(struct tcf_gact *gact)
  33 {
  34         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  35         if (prandom_u32() % gact->tcfg_pval)
  36                 return gact->tcf_action;
  37         return gact->tcfg_paction;
  38 }
  39
  40 static int gact_determ(struct tcf_gact *gact)
  41 {
  42         u32 pack = atomic_inc_return(&gact->packets);
  43
  44         smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
  45         if (pack % gact->tcfg_pval)
  46                 return gact->tcf_action;
  47         return gact->tcfg_paction;
  48 }
  49
  50 typedef int (*g_rand)(struct tcf_gact *gact);
  51 static g_rand gact_rand[MAX_RAND] = { NULL, gact_net_rand, gact_determ };
  52 #endif /* CONFIG_GACT_PROB */
  53
  54 static const struct nla_policy gact_policy[TCA_GACT_MAX + 1] = {
  55         [TCA_GACT_PARMS]        = { .len = sizeof(struct tc_gact) },
  56         [TCA_GACT_PROB]         = { .len = sizeof(struct tc_gact_p) },
  57 };
  58
  59 static int tcf_gact_init(struct net *net, struct nlattr *nla,
  60                          struct nlattr *est, struct tc_action **a,
  61                          int ovr, int bind)
  62 {
  63         struct tc_action_net *tn = net_generic(net, gact_net_id);
  64         struct nlattr *tb[TCA_GACT_MAX + 1];
  65         struct tc_gact *parm;
  66         struct tcf_gact *gact;
  67         int ret = 0;
  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);
  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
  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         }
  93 #endif
  94
  95         if (!tcf_hash_check(tn, parm->index, a, bind)) {
  96                 ret = tcf_hash_create(tn, parm->index, est, a,
  97                                       &act_gact_ops, bind, true);
  98                 if (ret)
  99                         return ret;
 100                 ret = ACT_P_CREATED;
 101         } else {
 102                 if (bind)/* dont override defaults */
 103                         return 0;
 104                 tcf_hash_release(*a, bind);
 105                 if (!ovr)
 106                         return -EEXIST;
 107         }
 108
 109         gact = to_gact(*a);
 110
 111         ASSERT_RTNL();
 112         gact->tcf_action = parm->action;
 113 #ifdef CONFIG_GACT_PROB
 114         if (p_parm) {
 115                 gact->tcfg_paction = p_parm->paction;
 116                 gact->tcfg_pval    = max_t(u16, 1, p_parm->pval);
 117                 /* Make sure tcfg_pval is written before tcfg_ptype
 118                  * coupled with smp_rmb() in gact_net_rand() & gact_determ()
 119                  */
 120                 smp_wmb();
 121                 gact->tcfg_ptype   = p_parm->ptype;
 122         }
 123 #endif
 124         if (ret == ACT_P_CREATED)
 125                 tcf_hash_insert(tn, *a);
 126         return ret;
 127 }
 128
 129 static int tcf_gact(struct sk_buff *skb, const struct tc_action *a,
 130                     struct tcf_result *res)
 131 {
 132         struct tcf_gact *gact = to_gact(a);
 133         int action = READ_ONCE(gact->tcf_action);
 134
 135 #ifdef CONFIG_GACT_PROB
 136         {
 137         u32 ptype = READ_ONCE(gact->tcfg_ptype);
 138
 139         if (ptype)
 140                 action = gact_rand[ptype](gact);
 141         }
 142 #endif
 143         bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), skb);
 144         if (action == TC_ACT_SHOT)
 145                 qstats_drop_inc(this_cpu_ptr(gact->common.cpu_qstats));
 146
 147         tcf_lastuse_update(&gact->tcf_tm);
 148
 149         return action;
 150 }
 151
 152 static void tcf_gact_stats_update(struct tc_action *a, u64 bytes, u32 packets,
 153                                   u64 lastuse)
 154 {
 155         struct tcf_gact *gact = to_gact(a);
 156         int action = READ_ONCE(gact->tcf_action);
 157         struct tcf_t *tm = &gact->tcf_tm;
 158
 159         _bstats_cpu_update(this_cpu_ptr(gact->common.cpu_bstats), bytes,
 160                            packets);
 161         if (action == TC_ACT_SHOT)
 162                 this_cpu_ptr(gact->common.cpu_qstats)->drops += packets;
 163
 164         tm->lastuse = lastuse;
 165 }
 166
 167 static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 168                          int bind, int ref)
 169 {
 170         unsigned char *b = skb_tail_pointer(skb);
 171         struct tcf_gact *gact = to_gact(a);
 172         struct tc_gact opt = {
 173                 .index   = gact->tcf_index,
 174                 .refcnt  = gact->tcf_refcnt - ref,
 175                 .bindcnt = gact->tcf_bindcnt - bind,
 176                 .action  = gact->tcf_action,
 177         };
 178         struct tcf_t t;
 179
 180         if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 181                 goto nla_put_failure;
 182 #ifdef CONFIG_GACT_PROB
 183         if (gact->tcfg_ptype) {
 184                 struct tc_gact_p p_opt = {
 185                         .paction = gact->tcfg_paction,
 186                         .pval    = gact->tcfg_pval,
 187                         .ptype   = gact->tcfg_ptype,
 188                 };
 189
 190                 if (nla_put(skb, TCA_GACT_PROB, sizeof(p_opt), &p_opt))
 191                         goto nla_put_failure;
 192         }
 193 #endif
 194         tcf_tm_dump(&t, &gact->tcf_tm);
 195         if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 196                 goto nla_put_failure;
 197         return skb->len;
 198
 199 nla_put_failure:
 200         nlmsg_trim(skb, b);
 201         return -1;
 202 }
 203
 204 static int tcf_gact_walker(struct net *net, struct sk_buff *skb,
 205                            struct netlink_callback *cb, int type,
 206                            const struct tc_action_ops *ops)
 207 {
 208         struct tc_action_net *tn = net_generic(net, gact_net_id);
 209
 210         return tcf_generic_walker(tn, skb, cb, type, ops);
 211 }
 212
 213 static int tcf_gact_search(struct net *net, struct tc_action **a, u32 index)
 214 {
 215         struct tc_action_net *tn = net_generic(net, gact_net_id);
 216
 217         return tcf_hash_search(tn, a, index);
 218 }
 219
 220 static struct tc_action_ops act_gact_ops = {
 221         .kind           =       "gact",
 222         .type           =       TCA_ACT_GACT,
 223         .owner          =       THIS_MODULE,
 224         .act            =       tcf_gact,
 225         .stats_update   =       tcf_gact_stats_update,
 226         .dump           =       tcf_gact_dump,
 227         .init           =       tcf_gact_init,
 228         .walk           =       tcf_gact_walker,
 229         .lookup         =       tcf_gact_search,
 230         .size           =       sizeof(struct tcf_gact),
 231 };
 232
 233 static __net_init int gact_init_net(struct net *net)
 234 {
 235         struct tc_action_net *tn = net_generic(net, gact_net_id);
 236
 237         return tc_action_net_init(tn, &act_gact_ops, GACT_TAB_MASK);
 238 }
 239
 240 static void __net_exit gact_exit_net(struct net *net)
 241 {
 242         struct tc_action_net *tn = net_generic(net, gact_net_id);
 243
 244         tc_action_net_exit(tn);
 245 }
 246
 247 static struct pernet_operations gact_net_ops = {
 248         .init = gact_init_net,
 249         .exit = gact_exit_net,
 250         .id   = &gact_net_id,
 251         .size = sizeof(struct tc_action_net),
 252 };
 253
 254 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 255 MODULE_DESCRIPTION("Generic Classifier actions");
 256 MODULE_LICENSE("GPL");
 257
 258 static int __init gact_init_module(void)
 259 {
 260 #ifdef CONFIG_GACT_PROB
 261         pr_info("GACT probability on\n");
 262 #else
 263         pr_info("GACT probability NOT on\n");
 264 #endif
 265
 266         return tcf_register_action(&act_gact_ops, &gact_net_ops);
 267 }
 268
 269 static void __exit gact_cleanup_module(void)
 270 {
 271         tcf_unregister_action(&act_gact_ops, &gact_net_ops);
 272 }
 273
 274 module_init(gact_init_module);
 275 module_exit(gact_cleanup_module);