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