linux/net/sched/act_pedit.c
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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 <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
  27static struct tcf_common *tcf_pedit_ht[PEDIT_TAB_MASK + 1];
  28static u32 pedit_idx_gen;
  29static DEFINE_RWLOCK(pedit_lock);
  30
  31static struct tcf_hashinfo pedit_hash_info = {
  32        .htab   =       tcf_pedit_ht,
  33        .hmask  =       PEDIT_TAB_MASK,
  34        .lock   =       &pedit_lock,
  35};
  36
  37static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  38        [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  39};
  40
  41static int tcf_pedit_init(struct nlattr *nla, struct nlattr *est,
  42                          struct tc_action *a, int ovr, int bind)
  43{
  44        struct nlattr *tb[TCA_PEDIT_MAX + 1];
  45        struct tc_pedit *parm;
  46        int ret = 0, err;
  47        struct tcf_pedit *p;
  48        struct tcf_common *pc;
  49        struct tc_pedit_key *keys = NULL;
  50        int ksize;
  51
  52        if (nla == NULL)
  53                return -EINVAL;
  54
  55        err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy);
  56        if (err < 0)
  57                return err;
  58
  59        if (tb[TCA_PEDIT_PARMS] == NULL)
  60                return -EINVAL;
  61        parm = nla_data(tb[TCA_PEDIT_PARMS]);
  62        ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  63        if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
  64                return -EINVAL;
  65
  66        pc = tcf_hash_check(parm->index, a, bind, &pedit_hash_info);
  67        if (!pc) {
  68                if (!parm->nkeys)
  69                        return -EINVAL;
  70                pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
  71                                     &pedit_idx_gen, &pedit_hash_info);
  72                if (IS_ERR(pc))
  73                        return PTR_ERR(pc);
  74                p = to_pedit(pc);
  75                keys = kmalloc(ksize, GFP_KERNEL);
  76                if (keys == NULL) {
  77                        if (est)
  78                                gen_kill_estimator(&pc->tcfc_bstats,
  79                                                   &pc->tcfc_rate_est);
  80                        kfree_rcu(pc, tcfc_rcu);
  81                        return -ENOMEM;
  82                }
  83                ret = ACT_P_CREATED;
  84        } else {
  85                p = to_pedit(pc);
  86                if (!ovr) {
  87                        tcf_hash_release(pc, bind, &pedit_hash_info);
  88                        return -EEXIST;
  89                }
  90                if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
  91                        keys = kmalloc(ksize, GFP_KERNEL);
  92                        if (keys == NULL)
  93                                return -ENOMEM;
  94                }
  95        }
  96
  97        spin_lock_bh(&p->tcf_lock);
  98        p->tcfp_flags = parm->flags;
  99        p->tcf_action = parm->action;
 100        if (keys) {
 101                kfree(p->tcfp_keys);
 102                p->tcfp_keys = keys;
 103                p->tcfp_nkeys = parm->nkeys;
 104        }
 105        memcpy(p->tcfp_keys, parm->keys, ksize);
 106        spin_unlock_bh(&p->tcf_lock);
 107        if (ret == ACT_P_CREATED)
 108                tcf_hash_insert(pc, &pedit_hash_info);
 109        return ret;
 110}
 111
 112static int tcf_pedit_cleanup(struct tc_action *a, int bind)
 113{
 114        struct tcf_pedit *p = a->priv;
 115
 116        if (p) {
 117                struct tc_pedit_key *keys = p->tcfp_keys;
 118                if (tcf_hash_release(&p->common, bind, &pedit_hash_info)) {
 119                        kfree(keys);
 120                        return 1;
 121                }
 122        }
 123        return 0;
 124}
 125
 126static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 127                     struct tcf_result *res)
 128{
 129        struct tcf_pedit *p = a->priv;
 130        int i, munged = 0;
 131        unsigned int off;
 132
 133        if (skb_cloned(skb) &&
 134            pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 135                return p->tcf_action;
 136
 137        off = skb_network_offset(skb);
 138
 139        spin_lock(&p->tcf_lock);
 140
 141        p->tcf_tm.lastuse = jiffies;
 142
 143        if (p->tcfp_nkeys > 0) {
 144                struct tc_pedit_key *tkey = p->tcfp_keys;
 145
 146                for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 147                        u32 *ptr, _data;
 148                        int offset = tkey->off;
 149
 150                        if (tkey->offmask) {
 151                                char *d, _d;
 152
 153                                d = skb_header_pointer(skb, off + tkey->at, 1,
 154                                                       &_d);
 155                                if (!d)
 156                                        goto bad;
 157                                offset += (*d & tkey->offmask) >> tkey->shift;
 158                        }
 159
 160                        if (offset % 4) {
 161                                pr_info("tc filter pedit"
 162                                        " offset must be on 32 bit boundaries\n");
 163                                goto bad;
 164                        }
 165                        if (offset > 0 && offset > skb->len) {
 166                                pr_info("tc filter pedit"
 167                                        " offset %d can't exceed pkt length %d\n",
 168                                       offset, skb->len);
 169                                goto bad;
 170                        }
 171
 172                        ptr = skb_header_pointer(skb, off + offset, 4, &_data);
 173                        if (!ptr)
 174                                goto bad;
 175                        /* just do it, baby */
 176                        *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 177                        if (ptr == &_data)
 178                                skb_store_bits(skb, off + offset, ptr, 4);
 179                        munged++;
 180                }
 181
 182                if (munged)
 183                        skb->tc_verd = SET_TC_MUNGED(skb->tc_verd);
 184                goto done;
 185        } else
 186                WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 187
 188bad:
 189        p->tcf_qstats.overlimits++;
 190done:
 191        bstats_update(&p->tcf_bstats, skb);
 192        spin_unlock(&p->tcf_lock);
 193        return p->tcf_action;
 194}
 195
 196static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 197                          int bind, int ref)
 198{
 199        unsigned char *b = skb_tail_pointer(skb);
 200        struct tcf_pedit *p = a->priv;
 201        struct tc_pedit *opt;
 202        struct tcf_t t;
 203        int s;
 204
 205        s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 206
 207        /* netlink spinlocks held above us - must use ATOMIC */
 208        opt = kzalloc(s, GFP_ATOMIC);
 209        if (unlikely(!opt))
 210                return -ENOBUFS;
 211
 212        memcpy(opt->keys, p->tcfp_keys,
 213               p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 214        opt->index = p->tcf_index;
 215        opt->nkeys = p->tcfp_nkeys;
 216        opt->flags = p->tcfp_flags;
 217        opt->action = p->tcf_action;
 218        opt->refcnt = p->tcf_refcnt - ref;
 219        opt->bindcnt = p->tcf_bindcnt - bind;
 220
 221        if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 222                goto nla_put_failure;
 223        t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
 224        t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
 225        t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
 226        if (nla_put(skb, TCA_PEDIT_TM, sizeof(t), &t))
 227                goto nla_put_failure;
 228        kfree(opt);
 229        return skb->len;
 230
 231nla_put_failure:
 232        nlmsg_trim(skb, b);
 233        kfree(opt);
 234        return -1;
 235}
 236
 237static struct tc_action_ops act_pedit_ops = {
 238        .kind           =       "pedit",
 239        .hinfo          =       &pedit_hash_info,
 240        .type           =       TCA_ACT_PEDIT,
 241        .capab          =       TCA_CAP_NONE,
 242        .owner          =       THIS_MODULE,
 243        .act            =       tcf_pedit,
 244        .dump           =       tcf_pedit_dump,
 245        .cleanup        =       tcf_pedit_cleanup,
 246        .lookup         =       tcf_hash_search,
 247        .init           =       tcf_pedit_init,
 248        .walk           =       tcf_generic_walker
 249};
 250
 251MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 252MODULE_DESCRIPTION("Generic Packet Editor actions");
 253MODULE_LICENSE("GPL");
 254
 255static int __init pedit_init_module(void)
 256{
 257        return tcf_register_action(&act_pedit_ops);
 258}
 259
 260static void __exit pedit_cleanup_module(void)
 261{
 262        tcf_unregister_action(&act_pedit_ops);
 263}
 264
 265module_init(pedit_init_module);
 266module_exit(pedit_cleanup_module);
 267
 268
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