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