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   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/config.h>
  13 #include <linux/module.h>
  14 #include <linux/types.h>
  15 #include <linux/kernel.h>
  16 #include <linux/sched.h>
  17 #include <linux/string.h>
  18 #include <linux/mm.h>
  19 #include <linux/errno.h>
  20 #include <linux/rtnetlink.h>
  21 #include <linux/skbuff.h>
  22 #include <net/act_api.h>
  23 #include <net/pkt_cls.h>
  24
  25 struct basic_head
  26 {
  27         u32                     hgenerator;
  28         struct list_head        flist;
  29 };
  30
  31 struct basic_filter
  32 {
  33         u32                     handle;
  34         struct tcf_exts         exts;
  35         struct tcf_ematch_tree  ematches;
  36         struct tcf_result       res;
  37         struct list_head        link;
  38 };
  39
  40 static struct tcf_ext_map basic_ext_map = {
  41         .action = TCA_BASIC_ACT,
  42         .police = TCA_BASIC_POLICE
  43 };
  44
  45 static int basic_classify(struct sk_buff *skb, struct tcf_proto *tp,
  46                           struct tcf_result *res)
  47 {
  48         int r;
  49         struct basic_head *head = (struct basic_head *) tp->root;
  50         struct basic_filter *f;
  51
  52         list_for_each_entry(f, &head->flist, link) {
  53                 if (!tcf_em_tree_match(skb, &f->ematches, NULL))
  54                         continue;
  55                 *res = f->res;
  56                 r = tcf_exts_exec(skb, &f->exts, res);
  57                 if (r < 0)
  58                         continue;
  59                 return r;
  60         }
  61         return -1;
  62 }
  63
  64 static unsigned long basic_get(struct tcf_proto *tp, u32 handle)
  65 {
  66         unsigned long l = 0UL;
  67         struct basic_head *head = (struct basic_head *) tp->root;
  68         struct basic_filter *f;
  69
  70         if (head == NULL)
  71                 return 0UL;
  72
  73         list_for_each_entry(f, &head->flist, link)
  74                 if (f->handle == handle)
  75                         l = (unsigned long) f;
  76
  77         return l;
  78 }
  79
  80 static void basic_put(struct tcf_proto *tp, unsigned long f)
  81 {
  82 }
  83
  84 static int basic_init(struct tcf_proto *tp)
  85 {
  86         return 0;
  87 }
  88
  89 static inline void basic_delete_filter(struct tcf_proto *tp,
  90                                        struct basic_filter *f)
  91 {
  92         tcf_unbind_filter(tp, &f->res);
  93         tcf_exts_destroy(tp, &f->exts);
  94         tcf_em_tree_destroy(tp, &f->ematches);
  95         kfree(f);
  96 }
  97
  98 static void basic_destroy(struct tcf_proto *tp)
  99 {
 100         struct basic_head *head = (struct basic_head *) xchg(&tp->root, NULL);
 101         struct basic_filter *f, *n;
 102
 103         list_for_each_entry_safe(f, n, &head->flist, link) {
 104                 list_del(&f->link);
 105                 basic_delete_filter(tp, f);
 106         }
 107 }
 108
 109 static int basic_delete(struct tcf_proto *tp, unsigned long arg)
 110 {
 111         struct basic_head *head = (struct basic_head *) tp->root;
 112         struct basic_filter *t, *f = (struct basic_filter *) arg;
 113
 114         list_for_each_entry(t, &head->flist, link)
 115                 if (t == f) {
 116                         tcf_tree_lock(tp);
 117                         list_del(&t->link);
 118                         tcf_tree_unlock(tp);
 119                         basic_delete_filter(tp, t);
 120                         return 0;
 121                 }
 122
 123         return -ENOENT;
 124 }
 125
 126 static inline int basic_set_parms(struct tcf_proto *tp, struct basic_filter *f,
 127                                   unsigned long base, struct rtattr **tb,
 128                                   struct rtattr *est)
 129 {
 130         int err = -EINVAL;
 131         struct tcf_exts e;
 132         struct tcf_ematch_tree t;
 133
 134         if (tb[TCA_BASIC_CLASSID-1])
 135                 if (RTA_PAYLOAD(tb[TCA_BASIC_CLASSID-1]) < sizeof(u32))
 136                         return err;
 137
 138         err = tcf_exts_validate(tp, tb, est, &e, &basic_ext_map);
 139         if (err < 0)
 140                 return err;
 141
 142         err = tcf_em_tree_validate(tp, tb[TCA_BASIC_EMATCHES-1], &t);
 143         if (err < 0)
 144                 goto errout;
 145
 146         if (tb[TCA_BASIC_CLASSID-1]) {
 147                 f->res.classid = *(u32*)RTA_DATA(tb[TCA_BASIC_CLASSID-1]);
 148                 tcf_bind_filter(tp, &f->res, base);
 149         }
 150
 151         tcf_exts_change(tp, &f->exts, &e);
 152         tcf_em_tree_change(tp, &f->ematches, &t);
 153
 154         return 0;
 155 errout:
 156         tcf_exts_destroy(tp, &e);
 157         return err;
 158 }
 159
 160 static int basic_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 161                         struct rtattr **tca, unsigned long *arg)
 162 {
 163         int err = -EINVAL;
 164         struct basic_head *head = (struct basic_head *) tp->root;
 165         struct rtattr *tb[TCA_BASIC_MAX];
 166         struct basic_filter *f = (struct basic_filter *) *arg;
 167
 168         if (tca[TCA_OPTIONS-1] == NULL)
 169                 return -EINVAL;
 170
 171         if (rtattr_parse_nested(tb, TCA_BASIC_MAX, tca[TCA_OPTIONS-1]) < 0)
 172                 return -EINVAL;
 173
 174         if (f != NULL) {
 175                 if (handle && f->handle != handle)
 176                         return -EINVAL;
 177                 return basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
 178         }
 179
 180         err = -ENOBUFS;
 181         if (head == NULL) {
 182                 head = kmalloc(sizeof(*head), GFP_KERNEL);
 183                 if (head == NULL)
 184                         goto errout;
 185
 186                 memset(head, 0, sizeof(*head));
 187                 INIT_LIST_HEAD(&head->flist);
 188                 tp->root = head;
 189         }
 190
 191         f = kmalloc(sizeof(*f), GFP_KERNEL);
 192         if (f == NULL)
 193                 goto errout;
 194         memset(f, 0, sizeof(*f));
 195
 196         err = -EINVAL;
 197         if (handle)
 198                 f->handle = handle;
 199         else {
 200                 int i = 0x80000000;
 201                 do {
 202                         if (++head->hgenerator == 0x7FFFFFFF)
 203                                 head->hgenerator = 1;
 204                 } while (--i > 0 && basic_get(tp, head->hgenerator));
 205
 206                 if (i <= 0) {
 207                         printk(KERN_ERR "Insufficient number of handles\n");
 208                         goto errout;
 209                 }
 210
 211                 f->handle = head->hgenerator;
 212         }
 213
 214         err = basic_set_parms(tp, f, base, tb, tca[TCA_RATE-1]);
 215         if (err < 0)
 216                 goto errout;
 217
 218         tcf_tree_lock(tp);
 219         list_add(&f->link, &head->flist);
 220         tcf_tree_unlock(tp);
 221         *arg = (unsigned long) f;
 222
 223         return 0;
 224 errout:
 225         if (*arg == 0UL && f)
 226                 kfree(f);
 227
 228         return err;
 229 }
 230
 231 static void basic_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 232 {
 233         struct basic_head *head = (struct basic_head *) tp->root;
 234         struct basic_filter *f;
 235
 236         list_for_each_entry(f, &head->flist, link) {
 237                 if (arg->count < arg->skip)
 238                         goto skip;
 239
 240                 if (arg->fn(tp, (unsigned long) f, arg) < 0) {
 241                         arg->stop = 1;
 242                         break;
 243                 }
 244 skip:
 245                 arg->count++;
 246         }
 247 }
 248
 249 static int basic_dump(struct tcf_proto *tp, unsigned long fh,
 250                       struct sk_buff *skb, struct tcmsg *t)
 251 {
 252         struct basic_filter *f = (struct basic_filter *) fh;
 253         unsigned char *b = skb->tail;
 254         struct rtattr *rta;
 255
 256         if (f == NULL)
 257                 return skb->len;
 258
 259         t->tcm_handle = f->handle;
 260
 261         rta = (struct rtattr *) b;
 262         RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
 263
 264         if (f->res.classid)
 265                 RTA_PUT(skb, TCA_BASIC_CLASSID, sizeof(u32), &f->res.classid);
 266
 267         if (tcf_exts_dump(skb, &f->exts, &basic_ext_map) < 0 ||
 268             tcf_em_tree_dump(skb, &f->ematches, TCA_BASIC_EMATCHES) < 0)
 269                 goto rtattr_failure;
 270
 271         rta->rta_len = (skb->tail - b);
 272         return skb->len;
 273
 274 rtattr_failure:
 275         skb_trim(skb, b - skb->data);
 276         return -1;
 277 }
 278
 279 static struct tcf_proto_ops cls_basic_ops = {
 280         .kind           =       "basic",
 281         .classify       =       basic_classify,
 282         .init           =       basic_init,
 283         .destroy        =       basic_destroy,
 284         .get            =       basic_get,
 285         .put            =       basic_put,
 286         .change         =       basic_change,
 287         .delete         =       basic_delete,
 288         .walk           =       basic_walk,
 289         .dump           =       basic_dump,
 290         .owner          =       THIS_MODULE,
 291 };
 292
 293 static int __init init_basic(void)
 294 {
 295         return register_tcf_proto_ops(&cls_basic_ops);
 296 }
 297
 298 static void __exit exit_basic(void)
 299 {
 300         unregister_tcf_proto_ops(&cls_basic_ops);
 301 }
 302
 303 module_init(init_basic)
 304 module_exit(exit_basic)
 305 MODULE_LICENSE("GPL");
 306