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