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