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