net/sched/act_pedit.c

   1 /*
   2  * net/sched/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 static u32 pedit_idx_gen;
  28
  29 static struct tcf_hashinfo pedit_hash_info;
  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 nlattr *tb[TCA_PEDIT_MAX + 1];
  40         struct tc_pedit *parm;
  41         int ret = 0, err;
  42         struct tcf_pedit *p;
  43         struct tcf_common *pc;
  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         pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
  62         if (!pc) {
  63                 if (!parm->nkeys)
  64                         return -EINVAL;
  65                 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
  66                                      &pedit_idx_gen, &pedit_hash_info);
  67                 if (IS_ERR(pc))
  68                         return PTR_ERR(pc);
  69                 p = to_pedit(pc);
  70                 keys = kmalloc(ksize, GFP_KERNEL);
  71                 if (keys == NULL) {
  72                         if (est)
  73                                 gen_kill_estimator(&pc->tcfc_bstats,
  74                                                    &pc->tcfc_rate_est);
  75                         kfree_rcu(pc, tcfc_rcu);
  76                         return -ENOMEM;
  77                 }
  78                 ret = ACT_P_CREATED;
  79         } else {
  80                 p = to_pedit(pc);
  81                 tcf_hash_release(pc, bind, &pedit_hash_info);
  82                 if (bind)
  83                         return 0;
  84                 if (!ovr)
  85                         return -EEXIST;
  86
  87                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
  88                         keys = kmalloc(ksize, GFP_KERNEL);
  89                         if (keys == NULL)
  90                                 return -ENOMEM;
  91                 }
  92         }
  93
  94         spin_lock_bh(&p->tcf_lock);
  95         p->tcfp_flags = parm->flags;
  96         p->tcf_action = parm->action;
  97         if (keys) {
  98                 kfree(p->tcfp_keys);
  99                 p->tcfp_keys = keys;
 100                 p->tcfp_nkeys = parm->nkeys;
 101         }
 102         memcpy(p->tcfp_keys, parm->keys, ksize);
 103         spin_unlock_bh(&p->tcf_lock);
 104         if (ret == ACT_P_CREATED)
 105                 tcf_hash_insert(pc, &pedit_hash_info);
 106         return ret;
 107 }
 108
 109 static int tcf_pedit_cleanup(struct tc_action *a, int bind)
 110 {
 111         struct tcf_pedit *p = a->priv;
 112
 113         if (p) {
 114                 struct tc_pedit_key *keys = p->tcfp_keys;
 115                 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
 116                         kfree(keys);
 117                         return 1;
 118                 }
 119         }
 120         return 0;
 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 = a->priv;
 127         int i, munged = 0;
 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         p->tcf_tm.lastuse = jiffies;
 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                                 d = skb_header_pointer(skb, off + tkey->at, 1,
 150                                                        &_d);
 151                                 if (!d)
 152                                         goto bad;
 153                                 offset += (*d & tkey->offmask) >> tkey->shift;
 154                         }
 155
 156                         if (offset % 4) {
 157                                 pr_info("tc filter pedit"
 158                                         " offset must be on 32 bit boundaries\n");
 159                                 goto bad;
 160                         }
 161                         if (offset > 0 && offset > skb->len) {
 162                                 pr_info("tc filter pedit"
 163                                         " offset %d can't exceed pkt length %d\n",
 164                                        offset, skb->len);
 165                                 goto bad;
 166                         }
 167
 168                         ptr = skb_header_pointer(skb, off + offset, 4, &_data);
 169                         if (!ptr)
 170                                 goto bad;
 171                         /* just do it, baby */
 172                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 173                         if (ptr == &_data)
 174                                 skb_store_bits(skb, off + offset, ptr, 4);
 175                         munged++;
 176                 }
 177
 178                 if (munged)
 179                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 180                 goto done;
 181         } else
 182                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 183
 184 bad:
 185         p->tcf_qstats.overlimits++;
 186 done:
 187         bstats_update(&p->tcf_bstats, skb);
 188         spin_unlock(&p->tcf_lock);
 189         return p->tcf_action;
 190 }
 191
 192 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 193                           int bind, int ref)
 194 {
 195         unsigned char *b = skb_tail_pointer(skb);
 196         struct tcf_pedit *p = a->priv;
 197         struct tc_pedit *opt;
 198         struct tcf_t t;
 199         int s;
 200
 201         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 202
 203         /* netlink spinlocks held above us - must use ATOMIC */
 204         opt = kzalloc(s, GFP_ATOMIC);
 205         if (unlikely(!opt))
 206                 return -ENOBUFS;
 207
 208         memcpy(opt->keys, p->tcfp_keys,
 209                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 210         opt->index = p->tcf_index;
 211         opt->nkeys = p->tcfp_nkeys;
 212         opt->flags = p->tcfp_flags;
 213         opt->action = p->tcf_action;
 214         opt->refcnt = p->tcf_refcnt - ref;
 215         opt->bindcnt = p->tcf_bindcnt - bind;
 216
 217         if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 218                 goto nla_put_failure;
 219         t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
 220         t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
 221         t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
 222         if (nla_put(skb, TCA_PEDIT_TM, sizeof(t), &t))
 223                 goto nla_put_failure;
 224         kfree(opt);
 225         return skb->len;
 226
 227 nla_put_failure:
 228         nlmsg_trim(skb, b);
 229         kfree(opt);
 230         return -1;
 231 }
 232
 233 static struct tc_action_ops act_pedit_ops = {
 234         .kind           =       "pedit",
 235         .hinfo          =       &pedit_hash_info,
 236         .type           =       TCA_ACT_PEDIT,
 237         .capab          =       TCA_CAP_NONE,
 238         .owner          =       THIS_MODULE,
 239         .act            =       tcf_pedit,
 240         .dump           =       tcf_pedit_dump,
 241         .cleanup        =       tcf_pedit_cleanup,
 242         .init           =       tcf_pedit_init,
 243 };
 244
 245 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 246 MODULE_DESCRIPTION("Generic Packet Editor actions");
 247 MODULE_LICENSE("GPL");
 248
 249 static int __init pedit_init_module(void)
 250 {
 251         int err = tcf_hashinfo_init(&pedit_hash_info, PEDIT_TAB_MASK);
 252         if (err)
 253                 return err;
 254         return tcf_register_action(&act_pedit_ops);
 255 }
 256
 257 static void __exit pedit_cleanup_module(void)
 258 {
 259         tcf_hashinfo_destroy(&pedit_hash_info);
 260         tcf_unregister_action(&act_pedit_ops);
 261 }
 262
 263 module_init(pedit_init_module);
 264 module_exit(pedit_cleanup_module);
 265