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 static unsigned int simp_net_id;
  28 static struct tc_action_ops act_simp_ops;
  29
  30 #define SIMP_MAX_DATA   32
  31 static int tcf_simp_act(struct sk_buff *skb, const struct tc_action *a,
  32                         struct tcf_result *res)
  33 {
  34         struct tcf_defact *d = to_defact(a);
  35
  36         spin_lock(&d->tcf_lock);
  37         tcf_lastuse_update(&d->tcf_tm);
  38         bstats_update(&d->tcf_bstats, skb);
  39
  40         /* print policy string followed by _ then packet count
  41          * Example if this was the 3rd packet and the string was "hello"
  42          * then it would look like "hello_3" (without quotes)
  43          */
  44         pr_info("simple: %s_%d\n",
  45                (char *)d->tcfd_defdata, d->tcf_bstats.packets);
  46         spin_unlock(&d->tcf_lock);
  47         return d->tcf_action;
  48 }
  49
  50 static void tcf_simp_release(struct tc_action *a)
  51 {
  52         struct tcf_defact *d = to_defact(a);
  53         kfree(d->tcfd_defdata);
  54 }
  55
  56 static int alloc_defdata(struct tcf_defact *d, const struct nlattr *defdata)
  57 {
  58         d->tcfd_defdata = kzalloc(SIMP_MAX_DATA, GFP_KERNEL);
  59         if (unlikely(!d->tcfd_defdata))
  60                 return -ENOMEM;
  61         nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  62         return 0;
  63 }
  64
  65 static void reset_policy(struct tcf_defact *d, const struct nlattr *defdata,
  66                          struct tc_defact *p)
  67 {
  68         spin_lock_bh(&d->tcf_lock);
  69         d->tcf_action = p->action;
  70         memset(d->tcfd_defdata, 0, SIMP_MAX_DATA);
  71         nla_strlcpy(d->tcfd_defdata, defdata, SIMP_MAX_DATA);
  72         spin_unlock_bh(&d->tcf_lock);
  73 }
  74
  75 static const struct nla_policy simple_policy[TCA_DEF_MAX + 1] = {
  76         [TCA_DEF_PARMS] = { .len = sizeof(struct tc_defact) },
  77         [TCA_DEF_DATA]  = { .type = NLA_STRING, .len = SIMP_MAX_DATA },
  78 };
  79
  80 static int tcf_simp_init(struct net *net, struct nlattr *nla,
  81                          struct nlattr *est, struct tc_action **a,
  82                          int ovr, int bind, bool rtnl_held,
  83                          struct netlink_ext_ack *extack)
  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         bool exists = false;
  90         int ret = 0, err;
  91
  92         if (nla == NULL)
  93                 return -EINVAL;
  94
  95         err = nla_parse_nested(tb, TCA_DEF_MAX, nla, simple_policy, NULL);
  96         if (err < 0)
  97                 return err;
  98
  99         if (tb[TCA_DEF_PARMS] == NULL)
 100                 return -EINVAL;
 101
 102         parm = nla_data(tb[TCA_DEF_PARMS]);
 103         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 104         if (err < 0)
 105                 return err;
 106         exists = err;
 107         if (exists && bind)
 108                 return 0;
 109
 110         if (tb[TCA_DEF_DATA] == NULL) {
 111                 if (exists)
 112                         tcf_idr_release(*a, bind);
 113                 else
 114                         tcf_idr_cleanup(tn, parm->index);
 115                 return -EINVAL;
 116         }
 117
 118         if (!exists) {
 119                 ret = tcf_idr_create(tn, parm->index, est, a,
 120                                      &act_simp_ops, bind, false);
 121                 if (ret) {
 122                         tcf_idr_cleanup(tn, parm->index);
 123                         return ret;
 124                 }
 125
 126                 d = to_defact(*a);
 127                 ret = alloc_defdata(d, tb[TCA_DEF_DATA]);
 128                 if (ret < 0) {
 129                         tcf_idr_release(*a, bind);
 130                         return ret;
 131                 }
 132                 d->tcf_action = parm->action;
 133                 ret = ACT_P_CREATED;
 134         } else {
 135                 d = to_defact(*a);
 136
 137                 if (!ovr) {
 138                         tcf_idr_release(*a, bind);
 139                         return -EEXIST;
 140                 }
 141
 142                 reset_policy(d, tb[TCA_DEF_DATA], parm);
 143         }
 144
 145         if (ret == ACT_P_CREATED)
 146                 tcf_idr_insert(tn, *a);
 147         return ret;
 148 }
 149
 150 static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 151                          int bind, int ref)
 152 {
 153         unsigned char *b = skb_tail_pointer(skb);
 154         struct tcf_defact *d = to_defact(a);
 155         struct tc_defact opt = {
 156                 .index   = d->tcf_index,
 157                 .refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 158                 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
 159         };
 160         struct tcf_t t;
 161
 162         spin_lock_bh(&d->tcf_lock);
 163         opt.action = d->tcf_action;
 164         if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 165             nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 166                 goto nla_put_failure;
 167
 168         tcf_tm_dump(&t, &d->tcf_tm);
 169         if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 170                 goto nla_put_failure;
 171         spin_unlock_bh(&d->tcf_lock);
 172
 173         return skb->len;
 174
 175 nla_put_failure:
 176         spin_unlock_bh(&d->tcf_lock);
 177         nlmsg_trim(skb, b);
 178         return -1;
 179 }
 180
 181 static int tcf_simp_walker(struct net *net, struct sk_buff *skb,
 182                            struct netlink_callback *cb, int type,
 183                            const struct tc_action_ops *ops,
 184                            struct netlink_ext_ack *extack)
 185 {
 186         struct tc_action_net *tn = net_generic(net, simp_net_id);
 187
 188         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 189 }
 190
 191 static int tcf_simp_search(struct net *net, struct tc_action **a, u32 index,
 192                            struct netlink_ext_ack *extack)
 193 {
 194         struct tc_action_net *tn = net_generic(net, simp_net_id);
 195
 196         return tcf_idr_search(tn, a, index);
 197 }
 198
 199 static struct tc_action_ops act_simp_ops = {
 200         .kind           =       "simple",
 201         .type           =       TCA_ACT_SIMP,
 202         .owner          =       THIS_MODULE,
 203         .act            =       tcf_simp_act,
 204         .dump           =       tcf_simp_dump,
 205         .cleanup        =       tcf_simp_release,
 206         .init           =       tcf_simp_init,
 207         .walk           =       tcf_simp_walker,
 208         .lookup         =       tcf_simp_search,
 209         .size           =       sizeof(struct tcf_defact),
 210 };
 211
 212 static __net_init int simp_init_net(struct net *net)
 213 {
 214         struct tc_action_net *tn = net_generic(net, simp_net_id);
 215
 216         return tc_action_net_init(tn, &act_simp_ops);
 217 }
 218
 219 static void __net_exit simp_exit_net(struct list_head *net_list)
 220 {
 221         tc_action_net_exit(net_list, simp_net_id);
 222 }
 223
 224 static struct pernet_operations simp_net_ops = {
 225         .init = simp_init_net,
 226         .exit_batch = simp_exit_net,
 227         .id   = &simp_net_id,
 228         .size = sizeof(struct tc_action_net),
 229 };
 230
 231 MODULE_AUTHOR("Jamal Hadi Salim(2005)");
 232 MODULE_DESCRIPTION("Simple example action");
 233 MODULE_LICENSE("GPL");
 234
 235 static int __init simp_init_module(void)
 236 {
 237         int ret = tcf_register_action(&act_simp_ops, &simp_net_ops);
 238         if (!ret)
 239                 pr_info("Simple TC action Loaded\n");
 240         return ret;
 241 }
 242
 243 static void __exit simp_cleanup_module(void)
 244 {
 245         tcf_unregister_action(&act_simp_ops, &simp_net_ops);
 246 }
 247
 248 module_init(simp_init_module);
 249 module_exit(simp_cleanup_module);