net/sched/act_simple.c

   1 /*
   2  * net/sched/act_simple.c       Simple example of an action
   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  * Authors:     Jamal Hadi Salim (2005-8)
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/rtnetlink.h>
  19 #include <net/netlink.h>
  20 #include <net/pkt_sched.h>
  21
  22 #define TCA_ACT_SIMP 22
  23
  24 #include <linux/tc_act/tc_defact.h>
  25 #include <net/tc_act/tc_defact.h>
  26
  27 #define SIMP_TAB_MASK     7
  28
  29 static int simp_net_id;
  30 static struct tc_action_ops act_simp_ops;
  31
  32 #define SIMP_MAX_DATA   32
  33 static int tcf_simp(struct sk_buff *skb, const struct tc_action *a,
  34                     struct tcf_result *res)
  35 {
  36         struct tcf_defact *d = to_defact(a);
  37
  38         spin_lock(&d->tcf_lock);
  39         tcf_lastuse_update(&d->tcf_tm);
  40         bstats_update(&d->tcf_bstats, skb);
  41
  42         /* print policy string followed by _ then packet count
  43          * Example if this was the 3rd packet and the string was "hello"
  44          * then it would look like "hello_3" (without quotes)
  45          */
  46         pr_info("simple: %s_%d\n",
  47                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  48         spin_unlock(&d->tcf_lock);
  49         return d->tcf_action;
  50 }
  51
  52 static void tcf_simp_release(struct tc_action *a, int bind)
  53 {
  54         struct tcf_defact *d = to_defact(a);
  55         kfree(d->tcfd_defdata);
  56 }
  57
  58 static int alloc_defdata(struct tcf_defact *d, char *defdata)
  59 {
  60         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  61         if (unlikely(!d->tcfd_defdata))
  62                 return -ENOMEM;
  63         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  64         return 0;
  65 }
  66
  67 static void reset_policy(struct tcf_defact *d, char *defdata,
  68                          struct tc_defact *p)
  69 {
  70         spin_lock_bh(&d->tcf_lock);
  71         d->tcf_action = p->action;
  72         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  73         strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  74         spin_unlock_bh(&d->tcf_lock);
  75 }
  76
  77 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  78         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  79         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  80 };
  81
  82 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  83                          struct nlattr *est, struct tc_action **a,
  84                          int ovr, int bind)
  85 {
  86         struct tc_action_net *tn = net_generic(net, simp_net_id);
  87         struct nlattr *tb[TCA_DEF_MAX + 1];
  88         struct tc_defact *parm;
  89         struct tcf_defact *d;
  90         bool exists = false;
  91         int ret = 0, err;
  92         char *defdata;
  93
  94         if (nla == NULL)
  95                 return -EINVAL;
  96
  97         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy);
  98         if (err < 0)
  99                 return err;
 100
 101         if (tb[TCA_DEF_PARMS] == NULL)
 102                 return -EINVAL;
 103
 104         parm = nla_data(tb[TCA_DEF_PARMS]);
 105         exists = tcf_hash_check(tn, parm->index, a, bind);
 106         if (exists && bind)
 107                 return 0;
 108
 109         if (tb[TCA_DEF_DATA] == NULL) {
 110                 if (exists)
 111                         tcf_hash_release(*a, bind);
 112                 return -EINVAL;
 113         }
 114
 115         defdata = nla_data(tb[TCA_DEF_DATA]);
 116
 117         if (!exists) {
 118                 ret = tcf_hash_create(tn, parm->index, est, a,
 119                                       &act_simp_ops, bind, false);
 120                 if (ret)
 121                         return ret;
 122
 123                 d = to_defact(*a);
 124                 ret = alloc_defdata(d, defdata);
 125                 if (ret < 0) {
 126                         tcf_hash_cleanup(*a, est);
 127                         return ret;
 128                 }
 129                 d->tcf_action = parm->action;
 130                 ret = ACT_P_CREATED;
 131         } else {
 132                 d = to_defact(*a);
 133
 134                 tcf_hash_release(*a, bind);
 135                 if (!ovr)
 136                         return -EEXIST;
 137
 138                 reset_policy(d, defdata, parm);
 139         }
 140
 141         if (ret == ACT_P_CREATED)
 142                 tcf_hash_insert(tn, *a);
 143         return ret;
 144 }
 145
 146 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 147                          int bind, int ref)
 148 {
 149         unsigned char *b = skb_tail_pointer(skb);
 150         struct tcf_defact *d = to_defact(a);
 151         struct tc_defact opt = {
 152                 .index   = d->tcf_index,
 153                 .refcnt  = d->tcf_refcnt - ref,
 154                 .bindcnt = d->tcf_bindcnt - bind,
 155                 .action  = d->tcf_action,
 156         };
 157         struct tcf_t t;
 158
 159         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 160             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 161                 goto nla_put_failure;
 162
 163         tcf_tm_dump(&t, &d->tcf_tm);
 164         if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 165                 goto nla_put_failure;
 166         return skb->len;
 167
 168 nla_put_failure:
 169         nlmsg_trim(skb, b);
 170         return -1;
 171 }
 172
 173 static int tcf_simp_walker(struct net *net, struct sk_buff *skb,
 174                            struct netlink_callback *cb, int type,
 175                            const struct tc_action_ops *ops)
 176 {
 177         struct tc_action_net *tn = net_generic(net, simp_net_id);
 178
 179         return tcf_generic_walker(tn, skb, cb, type, ops);
 180 }
 181
 182 static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index)
 183 {
 184         struct tc_action_net *tn = net_generic(net, simp_net_id);
 185
 186         return tcf_hash_search(tn, a, index);
 187 }
 188
 189 static struct tc_action_ops act_simp_ops = {
 190         .kind           =       "simple",
 191         .type           =       TCA_ACT_SIMP,
 192         .owner          =       THIS_MODULE,
 193         .act            =       tcf_simp,
 194         .dump           =       tcf_simp_dump,
 195         .cleanup        =       tcf_simp_release,
 196         .init           =       tcf_simp_init,
 197         .walk           =       tcf_simp_walker,
 198         .lookup         =       tcf_simp_search,
 199         .size           =       sizeof(struct tcf_defact),
 200 };
 201
 202 static __net_init int simp_init_net(struct net *net)
 203 {
 204         struct tc_action_net *tn = net_generic(net, simp_net_id);
 205
 206         return tc_action_net_init(tn, &act_simp_ops, SIMP_TAB_MASK);
 207 }
 208
 209 static void __net_exit simp_exit_net(struct net *net)
 210 {
 211         struct tc_action_net *tn = net_generic(net, simp_net_id);
 212
 213         tc_action_net_exit(tn);
 214 }
 215
 216 static struct pernet_operations simp_net_ops = {
 217         .init = simp_init_net,
 218         .exit = simp_exit_net,
 219         .id   = &simp_net_id,
 220         .size = sizeof(struct tc_action_net),
 221 };
 222
 223 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 224 MODULE_DESCRIPTION("Simple example action");
 225 MODULE_LICENSE("GPL");
 226
 227 static int __init simp_init_module(void)
 228 {
 229         int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 230         if (!ret)
 231                 pr_info("Simple TC action Loaded\n");
 232         return ret;
 233 }
 234
 235 static void __exit simp_cleanup_module(void)
 236 {
 237         tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 238 }
 239
 240 module_init(simp_init_module);
 241 module_exit(simp_cleanup_module);