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