net/sched/cls_basic.c

   1 /*
   2  * net/sched/cls_basic.c        Basic Packet Classifier.
   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:     Thomas Graf <tgraf@suug.ch>
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/string.h>
  16 #include <linux/mm.h>
  17 #include <linux/errno.h>
  18 #include <linux/rtnetlink.h>
  19 #include <linux/skbuff.h>
  20 #include <net/netlink.h>
  21 #include <net/act_api.h>
  22 #include <net/pkt_cls.h>
  23
  24 struct basic_head
  25 {
  26         u32                     hgenerator;
  27         struct list_head        flist;
  28 };
  29
  30 struct basic_filter
  31 {
  32         u32                     handle;
  33         struct tcf_exts         exts;
  34         struct tcf_ematch_tree  ematches;
  35         struct tcf_result       res;
  36         struct list_head        link;
  37 };
  38
  39 static struct tcf_ext_map basic_ext_map = {
  40         .action = TCA_BASIC_ACT,
  41         .police = TCA_BASIC_POLICE
  42 };
  43
  44 static int basic_classify(struct sk_buff *skb, struct tcf_proto *tp,
  45                           struct tcf_result *res)
  46 {
  47         int r;
  48         struct basic_head *head = (struct basic_head *) tp->root;
  49         struct basic_filter *f;
  50
  51         list_for_each_entry(f, &head->flist, link) {
  52                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  53                         continue;
  54                 *res = f->res;
  55                 r = tcf_exts_exec(skb, &f->exts, res);
  56                 if (r < 0)
  57                         continue;
  58                 return r;
  59         }
  60         return -1;
  61 }
  62
  63 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  64 {
  65         unsigned long l = 0UL;
  66         struct basic_head *head = (struct basic_head *) tp->root;
  67         struct basic_filter *f;
  68
  69         if (head == NULL)
  70                 return 0UL;
  71
  72         list_for_each_entry(f, &head->flist, link)
  73                 if (f->handle == handle)
  74                         l = (unsigned long) f;
  75
  76         return l;
  77 }
  78
  79 static void basic_put(struct tcf_proto *tp, unsigned long f)
  80 {
  81 }
  82
  83 static int basic_init(struct tcf_proto *tp)
  84 {
  85         struct basic_head *head;
  86
  87         head = kzalloc(sizeof(*head), GFP_KERNEL);
  88         if (head == NULL)
  89                 return -ENOBUFS;
  90         INIT_LIST_HEAD(&head->flist);
  91         tp->root = head;
  92         return 0;
  93 }
  94
  95 static inline void basic_delete_filter(struct tcf_proto *tp,
  96                                        struct basic_filter *f)
  97 {
  98         tcf_unbind_filter(tp, &f->res);
  99         tcf_exts_destroy(tp, &f->exts);
 100         tcf_em_tree_destroy(tp, &f->ematches);
 101         kfree(f);
 102 }
 103
 104 static void basic_destroy(struct tcf_proto *tp)
 105 {
 106         struct basic_head *head = (struct basic_head *) xchg(&tp->root, NULL);
 107         struct basic_filter *f, *n;
 108
 109         list_for_each_entry_safe(f, n, &head->flist, link) {
 110                 list_del(&f->link);
 111                 basic_delete_filter(tp, f);
 112         }
 113         kfree(head);
 114 }
 115
 116 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 117 {
 118         struct basic_head *head = (struct basic_head *) tp->root;
 119         struct basic_filter *t, *f = (struct basic_filter *) arg;
 120
 121         list_for_each_entry(t, &head->flist, link)
 122                 if (t == f) {
 123                         tcf_tree_lock(tp);
 124                         list_del(&t->link);
 125                         tcf_tree_unlock(tp);
 126                         basic_delete_filter(tp, t);
 127                         return 0;
 128                 }
 129
 130         return -ENOENT;
 131 }
 132
 133 static inline int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
 134                                   unsigned long base, struct rtattr **tb,
 135                                   struct rtattr *est)
 136 {
 137         int err = -EINVAL;
 138         struct tcf_exts e;
 139         struct tcf_ematch_tree t;
 140
 141         if (tb[TCA_BASIC_CLASSID-1])
 142                 if (RTA_PAYLOAD(tb[TCA_BASIC_CLASSID-1]) < sizeof(u32))
 143                         return err;
 144
 145         err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
 146         if (err < 0)
 147                 return err;
 148
 149         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES-1], &t);
 150         if (err < 0)
 151                 goto errout;
 152
 153         if (tb[TCA_BASIC_CLASSID-1]) {
 154                 f->res.classid = *(u32*)RTA_DATA(tb[TCA_BASIC_CLASSID-1]);
 155                 tcf_bind_filter(tp, &f->res, base);
 156         }
 157
 158         tcf_exts_change(tp, &f->exts, &e);
 159         tcf_em_tree_change(tp, &f->ematches, &t);
 160
 161         return 0;
 162 errout:
 163         tcf_exts_destroy(tp, &e);
 164         return err;
 165 }
 166
 167 static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 168                         struct rtattr **tca, unsigned long *arg)
 169 {
 170         int err = -EINVAL;
 171         struct basic_head *head = (struct basic_head *) tp->root;
 172         struct rtattr *tb[TCA_BASIC_MAX];
 173         struct basic_filter *f = (struct basic_filter *) *arg;
 174
 175         if (tca[TCA_OPTIONS-1] == NULL)
 176                 return -EINVAL;
 177
 178         if (rtattr_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS-1]) < 0)
 179                 return -EINVAL;
 180
 181         if (f != NULL) {
 182                 if (handle && f->handle != handle)
 183                         return -EINVAL;
 184                 return basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
 185         }
 186
 187         err = -ENOBUFS;
 188         f = kzalloc(sizeof(*f), GFP_KERNEL);
 189         if (f == NULL)
 190                 goto errout;
 191
 192         err = -EINVAL;
 193         if (handle)
 194                 f->handle = handle;
 195         else {
 196                 unsigned int i = 0x80000000;
 197                 do {
 198                         if (++head->hgenerator == 0x7FFFFFFF)
 199                                 head->hgenerator = 1;
 200                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 201
 202                 if (i <= 0) {
 203                         printk(KERN_ERR "Insufficient number of handles\n");
 204                         goto errout;
 205                 }
 206
 207                 f->handle = head->hgenerator;
 208         }
 209
 210         err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
 211         if (err < 0)
 212                 goto errout;
 213
 214         tcf_tree_lock(tp);
 215         list_add(&f->link, &head->flist);
 216         tcf_tree_unlock(tp);
 217         *arg = (unsigned long) f;
 218
 219         return 0;
 220 errout:
 221         if (*arg == 0UL && f)
 222                 kfree(f);
 223
 224         return err;
 225 }
 226
 227 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 228 {
 229         struct basic_head *head = (struct basic_head *) tp->root;
 230         struct basic_filter *f;
 231
 232         list_for_each_entry(f, &head->flist, link) {
 233                 if (arg->count < arg->skip)
 234                         goto skip;
 235
 236                 if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 237                         arg->stop = 1;
 238                         break;
 239                 }
 240 skip:
 241                 arg->count++;
 242         }
 243 }
 244
 245 static int basic_dump(struct tcf_proto *tp, unsigned long fh,
 246                       struct sk_buff *skb, struct tcmsg *t)
 247 {
 248         struct basic_filter *f = (struct basic_filter *) fh;
 249         unsigned char *b = skb_tail_pointer(skb);
 250         struct rtattr *rta;
 251
 252         if (f == NULL)
 253                 return skb->len;
 254
 255         t->tcm_handle = f->handle;
 256
 257         rta = (struct rtattr *) b;
 258         RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
 259
 260         if (f->res.classid)
 261                 RTA_PUT(skb, TCA_BASIC_CLASSID, sizeof(u32), &f->res.classid);
 262
 263         if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
 264             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 265                 goto rtattr_failure;
 266
 267         rta->rta_len = skb_tail_pointer(skb) - b;
 268         return skb->len;
 269
 270 rtattr_failure:
 271         nlmsg_trim(skb, b);
 272         return -1;
 273 }
 274
 275 static struct tcf_proto_ops cls_basic_ops = {
 276         .kind           =       "basic",
 277         .classify       =       basic_classify,
 278         .init           =       basic_init,
 279         .destroy        =       basic_destroy,
 280         .get            =       basic_get,
 281         .put            =       basic_put,
 282         .change         =       basic_change,
 283         .delete         =       basic_delete,
 284         .walk           =       basic_walk,
 285         .dump           =       basic_dump,
 286         .owner          =       THIS_MODULE,
 287 };
 288
 289 static int __init init_basic(void)
 290 {
 291         return register_tcf_proto_ops(&cls_basic_ops);
 292 }
 293
 294 static void __exit exit_basic(void)
 295 {
 296         unregister_tcf_proto_ops(&cls_basic_ops);
 297 }
 298
 299 module_init(init_basic)
 300 module_exit(exit_basic)
 301 MODULE_LICENSE("GPL");
 302