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