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   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 const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  37         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tcf_pedit) },
  38 };
  39
  40 static int tcf_pedit_init(struct nlattr *nla, struct nlattr *est,
  41                           struct tc_action *a, int ovr, int bind)
  42 {
  43         struct nlattr *tb[TCA_PEDIT_MAX + 1];
  44         struct tc_pedit *parm;
  45         int ret = 0, err;
  46         struct tcf_pedit *p;
  47         struct tcf_common *pc;
  48         struct tc_pedit_key *keys = NULL;
  49         int ksize;
  50
  51         if (nla == NULL)
  52                 return -EINVAL;
  53
  54         err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy);
  55         if (err < 0)
  56                 return err;
  57
  58         if (tb[TCA_PEDIT_PARMS] == NULL)
  59                 return -EINVAL;
  60         parm = nla_data(tb[TCA_PEDIT_PARMS]);
  61         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  62         if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
  63                 return -EINVAL;
  64
  65         pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
  66         if (!pc) {
  67                 if (!parm->nkeys)
  68                         return -EINVAL;
  69                 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
  70                                      &pedit_idx_gen, &pedit_hash_info);
  71                 if (unlikely(!pc))
  72                         return -ENOMEM;
  73                 p = to_pedit(pc);
  74                 keys = kmalloc(ksize, GFP_KERNEL);
  75                 if (keys == NULL) {
  76                         kfree(pc);
  77                         return -ENOMEM;
  78                 }
  79                 ret = ACT_P_CREATED;
  80         } else {
  81                 p = to_pedit(pc);
  82                 if (!ovr) {
  83                         tcf_hash_release(pc, bind, &pedit_hash_info);
  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, struct tc_action *a,
 123                      struct tcf_result *res)
 124 {
 125         struct tcf_pedit *p = a->priv;
 126         int i, munged = 0;
 127         u8 *pptr;
 128
 129         if (!(skb->tc_verd & TC_OK2MUNGE)) {
 130                 /* should we set skb->cloned? */
 131                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 132                         return p->tcf_action;
 133                 }
 134         }
 135
 136         pptr = skb_network_header(skb);
 137
 138         spin_lock(&p->tcf_lock);
 139
 140         p->tcf_tm.lastuse = jiffies;
 141
 142         if (p->tcfp_nkeys > 0) {
 143                 struct tc_pedit_key *tkey = p->tcfp_keys;
 144
 145                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 146                         u32 *ptr;
 147                         int offset = tkey->off;
 148
 149                         if (tkey->offmask) {
 150                                 if (skb->len > tkey->at) {
 151                                          char *j = pptr + tkey->at;
 152                                          offset += ((*j & tkey->offmask) >>
 153                                                    tkey->shift);
 154                                 } else {
 155                                         goto bad;
 156                                 }
 157                         }
 158
 159                         if (offset % 4) {
 160                                 printk("offset must be on 32 bit boundaries\n");
 161                                 goto bad;
 162                         }
 163                         if (offset > 0 && offset > skb->len) {
 164                                 printk("offset %d cant exceed pkt length %d\n",
 165                                        offset, skb->len);
 166                                 goto bad;
 167                         }
 168
 169                         ptr = (u32 *)(pptr+offset);
 170                         /* just do it, baby */
 171                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 172                         munged++;
 173                 }
 174
 175                 if (munged)
 176                         skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 177                 goto done;
 178         } else {
 179                 printk("pedit BUG: index %d\n", p->tcf_index);
 180         }
 181
 182 bad:
 183         p->tcf_qstats.overlimits++;
 184 done:
 185         p->tcf_bstats.bytes += qdisc_pkt_len(skb);
 186         p->tcf_bstats.packets++;
 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         NLA_PUT(skb, TCA_PEDIT_PARMS, s, opt);
 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         NLA_PUT(skb, TCA_PEDIT_TM, sizeof(t), &t);
 221         kfree(opt);
 222         return skb->len;
 223
 224 nla_put_failure:
 225         nlmsg_trim(skb, b);
 226         kfree(opt);
 227         return -1;
 228 }
 229
 230 static struct tc_action_ops act_pedit_ops = {
 231         .kind           =       "pedit",
 232         .hinfo          =       &pedit_hash_info,
 233         .type           =       TCA_ACT_PEDIT,
 234         .capab          =       TCA_CAP_NONE,
 235         .owner          =       THIS_MODULE,
 236         .act            =       tcf_pedit,
 237         .dump           =       tcf_pedit_dump,
 238         .cleanup        =       tcf_pedit_cleanup,
 239         .lookup         =       tcf_hash_search,
 240         .init           =       tcf_pedit_init,
 241         .walk           =       tcf_generic_walker
 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         return tcf_register_action(&act_pedit_ops);
 251 }
 252
 253 static void __exit pedit_cleanup_module(void)
 254 {
 255         tcf_unregister_action(&act_pedit_ops);
 256 }
 257
 258 module_init(pedit_init_module);
 259 module_exit(pedit_cleanup_module);
 260