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 <net/netlink.h>
  21 #include <net/pkt_sched.h>
  22 #include <linux/tc_act/tc_pedit.h>
  23 #include <net/tc_act/tc_pedit.h>
  24
  25 #define PEDIT_TAB_MASK  15
  26 static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1];
  27 static u32 pedit_idx_gen;
  28 static DEFINE_RWLOCK(pedit_lock);
  29
  30 static struct tcf_hashinfo pedit_hash_info = {
  31         .htab   =       tcf_pedit_ht,
  32         .hmask  =       PEDIT_TAB_MASK,
  33         .lock   =       &pedit_lock,
  34 };
  35
  36 static int tcf_pedit_init(struct nlattr *nla, struct nlattr *est,
  37                           struct tc_action *a, 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, NULL);
  51         if (err < 0)
  52                 return err;
  53
  54         if (tb[TCA_PEDIT_PARMS] == NULL ||
  55             nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm))
  56                 return -EINVAL;
  57         parm = nla_data(tb[TCA_PEDIT_PARMS]);
  58         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  59         if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
  60                 return -EINVAL;
  61
  62         pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
  63         if (!pc) {
  64                 if (!parm->nkeys)
  65                         return -EINVAL;
  66                 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
  67                                      &pedit_idx_gen, &pedit_hash_info);
  68                 if (unlikely(!pc))
  69                         return -ENOMEM;
  70                 p = to_pedit(pc);
  71                 keys = kmalloc(ksize, GFP_KERNEL);
  72                 if (keys == NULL) {
  73                         kfree(pc);
  74                         return -ENOMEM;
  75                 }
  76                 ret = ACT_P_CREATED;
  77         } else {
  78                 p = to_pedit(pc);
  79                 if (!ovr) {
  80                         tcf_hash_release(pc, bind, &pedit_hash_info);
  81                         return -EEXIST;
  82                 }
  83                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
  84                         keys = kmalloc(ksize, GFP_KERNEL);
  85                         if (keys == NULL)
  86                                 return -ENOMEM;
  87                 }
  88         }
  89
  90         spin_lock_bh(&p->tcf_lock);
  91         p->tcfp_flags = parm->flags;
  92         p->tcf_action = parm->action;
  93         if (keys) {
  94                 kfree(p->tcfp_keys);
  95                 p->tcfp_keys = keys;
  96                 p->tcfp_nkeys = parm->nkeys;
  97         }
  98         memcpy(p->tcfp_keys, parm->keys, ksize);
  99         spin_unlock_bh(&p->tcf_lock);
 100         if (ret == ACT_P_CREATED)
 101                 tcf_hash_insert(pc, &pedit_hash_info);
 102         return ret;
 103 }
 104
 105 static int tcf_pedit_cleanup(struct tc_action *a, int bind)
 106 {
 107         struct tcf_pedit *p = a->priv;
 108
 109         if (p) {
 110                 struct tc_pedit_key *keys = p->tcfp_keys;
 111                 if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
 112                         kfree(keys);
 113                         return 1;
 114                 }
 115         }
 116         return 0;
 117 }
 118
 119 static int tcf_pedit(struct sk_buff *skb, struct tc_action *a,
 120                      struct tcf_result *res)
 121 {
 122         struct tcf_pedit *p = a->priv;
 123         int i, munged = 0;
 124         u8 *pptr;
 125
 126         if (!(skb->tc_verd & TC_OK2MUNGE)) {
 127                 /* should we set skb->cloned? */
 128                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 129                         return p->tcf_action;
 130                 }
 131         }
 132
 133         pptr = skb_network_header(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;
 144                         int offset = tkey->off;
 145
 146                         if (tkey->offmask) {
 147                                 if (skb->len > tkey->at) {
 148                                          char *j = pptr + tkey->at;
 149                                          offset += ((*j & tkey->offmask) >>
 150                                                    tkey->shift);
 151                                 } else {
 152                                         goto bad;
 153                                 }
 154                         }
 155
 156                         if (offset % 4) {
 157                                 printk("offset must be on 32 bit boundaries\n");
 158                                 goto bad;
 159                         }
 160                         if (offset > 0 && offset > skb->len) {
 161                                 printk("offset %d cant exceed pkt length %d\n",
 162                                        offset, skb->len);
 163                                 goto bad;
 164                         }
 165
 166                         ptr = (u32 *)(pptr+offset);
 167                         /* just do it, baby */
 168                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 169                         munged++;
 170                 }
 171
 172                 if (munged)
 173                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 174                 goto done;
 175         } else {
 176                 printk("pedit BUG: index %d\n", p->tcf_index);
 177         }
 178
 179 bad:
 180         p->tcf_qstats.overlimits++;
 181 done:
 182         p->tcf_bstats.bytes += skb->len;
 183         p->tcf_bstats.packets++;
 184         spin_unlock(&p->tcf_lock);
 185         return p->tcf_action;
 186 }
 187
 188 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 189                           int bind, int ref)
 190 {
 191         unsigned char *b = skb_tail_pointer(skb);
 192         struct tcf_pedit *p = a->priv;
 193         struct tc_pedit *opt;
 194         struct tcf_t t;
 195         int s;
 196
 197         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 198
 199         /* netlink spinlocks held above us - must use ATOMIC */
 200         opt = kzalloc(s, GFP_ATOMIC);
 201         if (unlikely(!opt))
 202                 return -ENOBUFS;
 203
 204         memcpy(opt->keys, p->tcfp_keys,
 205                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 206         opt->index = p->tcf_index;
 207         opt->nkeys = p->tcfp_nkeys;
 208         opt->flags = p->tcfp_flags;
 209         opt->action = p->tcf_action;
 210         opt->refcnt = p->tcf_refcnt - ref;
 211         opt->bindcnt = p->tcf_bindcnt - bind;
 212
 213         NLA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
 214         t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
 215         t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
 216         t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
 217         NLA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
 218         kfree(opt);
 219         return skb->len;
 220
 221 nla_put_failure:
 222         nlmsg_trim(skb, b);
 223         kfree(opt);
 224         return -1;
 225 }
 226
 227 static struct tc_action_ops act_pedit_ops = {
 228         .kind           =       "pedit",
 229         .hinfo          =       &pedit_hash_info,
 230         .type           =       TCA_ACT_PEDIT,
 231         .capab          =       TCA_CAP_NONE,
 232         .owner          =       THIS_MODULE,
 233         .act            =       tcf_pedit,
 234         .dump           =       tcf_pedit_dump,
 235         .cleanup        =       tcf_pedit_cleanup,
 236         .lookup         =       tcf_hash_search,
 237         .init           =       tcf_pedit_init,
 238         .walk           =       tcf_generic_walker
 239 };
 240
 241 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 242 MODULE_DESCRIPTION("Generic Packet Editor actions");
 243 MODULE_LICENSE("GPL");
 244
 245 static int __init pedit_init_module(void)
 246 {
 247         return tcf_register_action(&act_pedit_ops);
 248 }
 249
 250 static void __exit pedit_cleanup_module(void)
 251 {
 252         tcf_unregister_action(&act_pedit_ops);
 253 }
 254
 255 module_init(pedit_init_module);
 256 module_exit(pedit_cleanup_module);
 257