net/sched/act_pedit.c

   1 /*
   2  * net/sched/act_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 int pedit_net_id;
  29 static struct tc_action_ops act_pedit_ops;
  30
  31 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  32         [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  33 };
  34
  35 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
  36                           struct nlattr *est, struct tc_action **a,
  37                           int ovr, int bind)
  38 {
  39         struct tc_action_net *tn = net_generic(net, pedit_net_id);
  40         struct nlattr *tb[TCA_PEDIT_MAX + 1];
  41         struct tc_pedit *parm;
  42         int ret = 0, err;
  43         struct tcf_pedit *p;
  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, pedit_policy);
  51         if (err < 0)
  52                 return err;
  53
  54         if (tb[TCA_PEDIT_PARMS] == NULL)
  55                 return -EINVAL;
  56         parm = nla_data(tb[TCA_PEDIT_PARMS]);
  57         ksize = parm->nkeys * sizeof(struct tc_pedit_key);
  58         if (nla_len(tb[TCA_PEDIT_PARMS]) < sizeof(*parm) + ksize)
  59                 return -EINVAL;
  60
  61         if (!tcf_hash_check(tn, parm->index, a, bind)) {
  62                 if (!parm->nkeys)
  63                         return -EINVAL;
  64                 ret = tcf_hash_create(tn, parm->index, est, a,
  65                                       &act_pedit_ops, bind, false);
  66                 if (ret)
  67                         return ret;
  68                 p = to_pedit(*a);
  69                 keys = kmalloc(ksize, GFP_KERNEL);
  70                 if (keys == NULL) {
  71                         tcf_hash_cleanup(*a, est);
  72                         return -ENOMEM;
  73                 }
  74                 ret = ACT_P_CREATED;
  75         } else {
  76                 if (bind)
  77                         return 0;
  78                 tcf_hash_release(*a, bind);
  79                 if (!ovr)
  80                         return -EEXIST;
  81                 p = to_pedit(*a);
  82                 if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
  83                         keys = kmalloc(ksize, GFP_KERNEL);
  84                         if (keys == NULL)
  85                                 return -ENOMEM;
  86                 }
  87         }
  88
  89         spin_lock_bh(&p->tcf_lock);
  90         p->tcfp_flags = parm->flags;
  91         p->tcf_action = parm->action;
  92         if (keys) {
  93                 kfree(p->tcfp_keys);
  94                 p->tcfp_keys = keys;
  95                 p->tcfp_nkeys = parm->nkeys;
  96         }
  97         memcpy(p->tcfp_keys, parm->keys, ksize);
  98         spin_unlock_bh(&p->tcf_lock);
  99         if (ret == ACT_P_CREATED)
 100                 tcf_hash_insert(tn, *a);
 101         return ret;
 102 }
 103
 104 static void tcf_pedit_cleanup(struct tc_action *a, int bind)
 105 {
 106         struct tcf_pedit *p = to_pedit(a);
 107         struct tc_pedit_key *keys = p->tcfp_keys;
 108         kfree(keys);
 109 }
 110
 111 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
 112                      struct tcf_result *res)
 113 {
 114         struct tcf_pedit *p = to_pedit(a);
 115         int i;
 116         unsigned int off;
 117
 118         if (skb_unclone(skb, GFP_ATOMIC))
 119                 return p->tcf_action;
 120
 121         off = skb_network_offset(skb);
 122
 123         spin_lock(&p->tcf_lock);
 124
 125         tcf_lastuse_update(&p->tcf_tm);
 126
 127         if (p->tcfp_nkeys > 0) {
 128                 struct tc_pedit_key *tkey = p->tcfp_keys;
 129
 130                 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 131                         u32 *ptr, _data;
 132                         int offset = tkey->off;
 133
 134                         if (tkey->offmask) {
 135                                 char *d, _d;
 136
 137                                 d = skb_header_pointer(skb, off + tkey->at, 1,
 138                                                        &_d);
 139                                 if (!d)
 140                                         goto bad;
 141                                 offset += (*d & tkey->offmask) >> tkey->shift;
 142                         }
 143
 144                         if (offset % 4) {
 145                                 pr_info("tc filter pedit"
 146                                         " offset must be on 32 bit boundaries\n");
 147                                 goto bad;
 148                         }
 149                         if (offset > 0 && offset > skb->len) {
 150                                 pr_info("tc filter pedit"
 151                                         " offset %d can't exceed pkt length %d\n",
 152                                        offset, skb->len);
 153                                 goto bad;
 154                         }
 155
 156                         ptr = skb_header_pointer(skb, off + offset, 4, &_data);
 157                         if (!ptr)
 158                                 goto bad;
 159                         /* just do it, baby */
 160                         *ptr = ((*ptr & tkey->mask) ^ tkey->val);
 161                         if (ptr == &_data)
 162                                 skb_store_bits(skb, off + offset, ptr, 4);
 163                 }
 164
 165                 goto done;
 166         } else
 167                 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 168
 169 bad:
 170         p->tcf_qstats.overlimits++;
 171 done:
 172         bstats_update(&p->tcf_bstats, skb);
 173         spin_unlock(&p->tcf_lock);
 174         return p->tcf_action;
 175 }
 176
 177 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 178                           int bind, int ref)
 179 {
 180         unsigned char *b = skb_tail_pointer(skb);
 181         struct tcf_pedit *p = to_pedit(a);
 182         struct tc_pedit *opt;
 183         struct tcf_t t;
 184         int s;
 185
 186         s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
 187
 188         /* netlink spinlocks held above us - must use ATOMIC */
 189         opt = kzalloc(s, GFP_ATOMIC);
 190         if (unlikely(!opt))
 191                 return -ENOBUFS;
 192
 193         memcpy(opt->keys, p->tcfp_keys,
 194                p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 195         opt->index = p->tcf_index;
 196         opt->nkeys = p->tcfp_nkeys;
 197         opt->flags = p->tcfp_flags;
 198         opt->action = p->tcf_action;
 199         opt->refcnt = p->tcf_refcnt - ref;
 200         opt->bindcnt = p->tcf_bindcnt - bind;
 201
 202         if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 203                 goto nla_put_failure;
 204
 205         tcf_tm_dump(&t, &p->tcf_tm);
 206         if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 207                 goto nla_put_failure;
 208
 209         kfree(opt);
 210         return skb->len;
 211
 212 nla_put_failure:
 213         nlmsg_trim(skb, b);
 214         kfree(opt);
 215         return -1;
 216 }
 217
 218 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 219                             struct netlink_callback *cb, int type,
 220                             const struct tc_action_ops *ops)
 221 {
 222         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 223
 224         return tcf_generic_walker(tn, skb, cb, type, ops);
 225 }
 226
 227 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 228 {
 229         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 230
 231         return tcf_hash_search(tn, a, index);
 232 }
 233
 234 static struct tc_action_ops act_pedit_ops = {
 235         .kind           =       "pedit",
 236         .type           =       TCA_ACT_PEDIT,
 237         .owner          =       THIS_MODULE,
 238         .act            =       tcf_pedit,
 239         .dump           =       tcf_pedit_dump,
 240         .cleanup        =       tcf_pedit_cleanup,
 241         .init           =       tcf_pedit_init,
 242         .walk           =       tcf_pedit_walker,
 243         .lookup         =       tcf_pedit_search,
 244         .size           =       sizeof(struct tcf_pedit),
 245 };
 246
 247 static __net_init int pedit_init_net(struct net *net)
 248 {
 249         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 250
 251         return tc_action_net_init(tn, &act_pedit_ops, PEDIT_TAB_MASK);
 252 }
 253
 254 static void __net_exit pedit_exit_net(struct net *net)
 255 {
 256         struct tc_action_net *tn = net_generic(net, pedit_net_id);
 257
 258         tc_action_net_exit(tn);
 259 }
 260
 261 static struct pernet_operations pedit_net_ops = {
 262         .init = pedit_init_net,
 263         .exit = pedit_exit_net,
 264         .id   = &pedit_net_id,
 265         .size = sizeof(struct tc_action_net),
 266 };
 267
 268 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 269 MODULE_DESCRIPTION("Generic Packet Editor actions");
 270 MODULE_LICENSE("GPL");
 271
 272 static int __init pedit_init_module(void)
 273 {
 274         return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 275 }
 276
 277 static void __exit pedit_cleanup_module(void)
 278 {
 279         tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 280 }
 281
 282 module_init(pedit_init_module);
 283 module_exit(pedit_cleanup_module);
 284