net/sched/act_pedit.c

   1 /*
   2  * net/sched/act_pedit.c        Generic packet editor
   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 (2002-4)
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/kernel.h>
  14 #include <linux/string.h>
  15 #include <linux/errno.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/rtnetlink.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/slab.h>
  21 #include <net/netlink.h>
  22 #include <net/pkt_sched.h>
  23 #include <linux/tc_act/tc_pedit.h>
  24 #include <net/tc_act/tc_pedit.h>
  25
  26 #define PEDIT_TAB_MASK  15
  27
  28 static int pedit_net_id;
  29 static struct tc_action_ops act_pedit_ops;
  30
  31 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  32         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  33 };
  34
  35 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
  36                           struct nlattr *est, struct tc_action **a,
  37                           int ovr, int bind)
  38 {
  39         struct tc_action_net *tn = net_generic(net, pedit_net_id);
  40         struct nlattr *tb[TCA_PEDIT_MAX + 1];
  41         struct tc_pedit *parm;
  42         int ret = 0, err;
  43         struct tcf_pedit *p;
  44         struct tc_pedit_key *keys = NULL;
  45         int ksize;
  46
  47         if (nla == NULL)
  48                 return -EINVAL;
  49
  50         err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy);
  51         if (err < 0)
  52                 return err;
  53
  54         if (tb[TCA_PEDIT_PARMS] == NULL)
  55                 return -EINVAL;
  56         parm = nla_data(tb[TCA_PEDIT_PARMS]);
  57         if (!parm->nkeys)
  58                 return -EINVAL;
  59
  60         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  61         if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
  62                 return -EINVAL;
  63
  64         if (!tcf_hash_check(tn, parm->index, a, bind)) {
  65                 ret = tcf_hash_create(tn, parm->index, est, a,
  66                                       &act_pedit_ops, bind, false);
  67                 if (ret)
  68                         return ret;
  69                 p = to_pedit(*a);
  70                 keys = kmalloc(ksize, GFP_KERNEL);
  71                 if (keys == NULL) {
  72                         tcf_hash_cleanup(*a, est);
  73                         return -ENOMEM;
  74                 }
  75                 ret = ACT_P_CREATED;
  76         } else {
  77                 if (bind)
  78                         return 0;
  79                 tcf_hash_release(*a, bind);
  80                 if (!ovr)
  81                         return -EEXIST;
  82                 p = to_pedit(*a);
  83                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
  84                         keys = kmalloc(ksize, GFP_KERNEL);
  85                         if (keys == NULL)
  86                                 return -ENOMEM;
  87                 }
  88         }
  89
  90         spin_lock_bh(&p->tcf_lock);
  91         p->tcfp_flags = parm->flags;
  92         p->tcf_action = parm->action;
  93         if (keys) {
  94                 kfree(p->tcfp_keys);
  95                 p->tcfp_keys = keys;
  96                 p->tcfp_nkeys = parm->nkeys;
  97         }
  98         memcpy(p->tcfp_keys, parm->keys, ksize);
  99         spin_unlock_bh(&p->tcf_lock);
 100         if (ret == ACT_P_CREATED)
 101                 tcf_hash_insert(tn, *a);
 102         return ret;
 103 }
 104
 105 static void tcf_pedit_cleanup(struct tc_action *a, int bind)
 106 {
 107         struct tcf_pedit *p = to_pedit(a);
 108         struct tc_pedit_key *keys = p->tcfp_keys;
 109         kfree(keys);
 110 }
 111
 112 static bool offset_valid(struct sk_buff *skb, int offset)
 113 {
 114         if (offset > 0 && offset > skb->len)
 115                 return false;
 116
 117         if  (offset < 0 && -offset > skb_headroom(skb))
 118                 return false;
 119
 120         return true;
 121 }
 122
 123 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 124                      struct tcf_result *res)
 125 {
 126         struct tcf_pedit *p = to_pedit(a);
 127         int i;
 128         unsigned int off;
 129
 130         if (skb_unclone(skb, GFP_ATOMIC))
 131                 return p->tcf_action;
 132
 133         off = skb_network_offset(skb);
 134
 135         spin_lock(&p->tcf_lock);
 136
 137         tcf_lastuse_update(&p->tcf_tm);
 138
 139         if (p->tcfp_nkeys > 0) {
 140                 struct tc_pedit_key *tkey = p->tcfp_keys;
 141
 142                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 143                         u32 *ptr, _data;
 144                         int offset = tkey->off;
 145
 146                         if (tkey->offmask) {
 147                                 char *d, _d;
 148
 149                                 if (!offset_valid(skb, off + tkey->at)) {
 150                                         pr_info("tc filter pedit 'at' offset %d out of bounds\n",
 151                                                 off + tkey->at);
 152                                         goto bad;
 153                                 }
 154                                 d = skb_header_pointer(skb, off + tkey->at, 1,
 155                                                        &_d);
 156                                 if (!d)
 157                                         goto bad;
 158                                 offset += (*d & tkey->offmask) >> tkey->shift;
 159                         }
 160
 161                         if (offset % 4) {
 162                                 pr_info("tc filter pedit"
 163                                         " offset must be on 32 bit boundaries\n");
 164                                 goto bad;
 165                         }
 166
 167                         if (!offset_valid(skb, off + offset)) {
 168                                 pr_info("tc filter pedit offset %d out of bounds\n",
 169                                         offset);
 170                                 goto bad;
 171                         }
 172
 173                         ptr = skb_header_pointer(skb, off + offset, 4, &_data);
 174                         if (!ptr)
 175                                 goto bad;
 176                         /* just do it, baby */
 177                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 178                         if (ptr == &_data)
 179                                 skb_store_bits(skb, off + offset, ptr, 4);
 180                 }
 181
 182                 goto done;
 183         } else
 184                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 185
 186 bad:
 187         p->tcf_qstats.overlimits++;
 188 done:
 189         bstats_update(&p->tcf_bstats, skb);
 190         spin_unlock(&p->tcf_lock);
 191         return p->tcf_action;
 192 }
 193
 194 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 195                           int bind, int ref)
 196 {
 197         unsigned char *b = skb_tail_pointer(skb);
 198         struct tcf_pedit *p = to_pedit(a);
 199         struct tc_pedit *opt;
 200         struct tcf_t t;
 201         int s;
 202
 203         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 204
 205         /* netlink spinlocks held above us - must use ATOMIC */
 206         opt = kzalloc(s, GFP_ATOMIC);
 207         if (unlikely(!opt))
 208                 return -ENOBUFS;
 209
 210         memcpy(opt->keys, p->tcfp_keys,
 211                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 212         opt->index = p->tcf_index;
 213         opt->nkeys = p->tcfp_nkeys;
 214         opt->flags = p->tcfp_flags;
 215         opt->action = p->tcf_action;
 216         opt->refcnt = p->tcf_refcnt - ref;
 217         opt->bindcnt = p->tcf_bindcnt - bind;
 218
 219         if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 220                 goto nla_put_failure;
 221
 222         tcf_tm_dump(&t, &p->tcf_tm);
 223         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 224                 goto nla_put_failure;
 225
 226         kfree(opt);
 227         return skb->len;
 228
 229 nla_put_failure:
 230         nlmsg_trim(skb, b);
 231         kfree(opt);
 232         return -1;
 233 }
 234
 235 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 236                             struct netlink_callback *cb, int type,
 237                             const struct tc_action_ops *ops)
 238 {
 239         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 240
 241         return tcf_generic_walker(tn, skb, cb, type, ops);
 242 }
 243
 244 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 245 {
 246         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 247
 248         return tcf_hash_search(tn, a, index);
 249 }
 250
 251 static struct tc_action_ops act_pedit_ops = {
 252         .kind           =       "pedit",
 253         .type           =       TCA_ACT_PEDIT,
 254         .owner          =       THIS_MODULE,
 255         .act            =       tcf_pedit,
 256         .dump           =       tcf_pedit_dump,
 257         .cleanup        =       tcf_pedit_cleanup,
 258         .init           =       tcf_pedit_init,
 259         .walk           =       tcf_pedit_walker,
 260         .lookup         =       tcf_pedit_search,
 261         .size           =       sizeof(struct tcf_pedit),
 262 };
 263
 264 static __net_init int pedit_init_net(struct net *net)
 265 {
 266         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 267
 268         return tc_action_net_init(tn, &act_pedit_ops, PEDIT_TAB_MASK);
 269 }
 270
 271 static void __net_exit pedit_exit_net(struct net *net)
 272 {
 273         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 274
 275         tc_action_net_exit(tn);
 276 }
 277
 278 static struct pernet_operations pedit_net_ops = {
 279         .init = pedit_init_net,
 280         .exit = pedit_exit_net,
 281         .id   = &pedit_net_id,
 282         .size = sizeof(struct tc_action_net),
 283 };
 284
 285 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 286 MODULE_DESCRIPTION("Generic Packet Editor actions");
 287 MODULE_LICENSE("GPL");
 288
 289 static int __init pedit_init_module(void)
 290 {
 291         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 292 }
 293
 294 static void __exit pedit_cleanup_module(void)
 295 {
 296         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 297 }
 298
 299 module_init(pedit_init_module);
 300 module_exit(pedit_cleanup_module);
 301