net/sched/act_skbedit.c

   1 /*
   2  * Copyright (c) 2008, Intel Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, see <http://www.gnu.org/licenses/>.
  15  *
  16  * Author: Alexander Duyck <alexander.h.duyck@intel.com>
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/skbuff.h>
  23 #include <linux/rtnetlink.h>
  24 #include <net/netlink.h>
  25 #include <net/pkt_sched.h>
  26 #include <net/ip.h>
  27 #include <net/ipv6.h>
  28 #include <net/dsfield.h>
  29
  30 #include <linux/tc_act/tc_skbedit.h>
  31 #include <net/tc_act/tc_skbedit.h>
  32
  33 static unsigned int skbedit_net_id;
  34 static struct tc_action_ops act_skbedit_ops;
  35
  36 static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a,
  37                            struct tcf_result *res)
  38 {
  39         struct tcf_skbedit *d = to_skbedit(a);
  40         struct tcf_skbedit_params *params;
  41         int action;
  42
  43         tcf_lastuse_update(&d->tcf_tm);
  44         bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);
  45
  46         params = rcu_dereference_bh(d->params);
  47         action = READ_ONCE(d->tcf_action);
  48
  49         if (params->flags & SKBEDIT_F_PRIORITY)
  50                 skb->priority = params->priority;
  51         if (params->flags & SKBEDIT_F_INHERITDSFIELD) {
  52                 int wlen = skb_network_offset(skb);
  53
  54                 switch (tc_skb_protocol(skb)) {
  55                 case htons(ETH_P_IP):
  56                         wlen += sizeof(struct iphdr);
  57                         if (!pskb_may_pull(skb, wlen))
  58                                 goto err;
  59                         skb->priority = ipv4_get_dsfield(ip_hdr(skb)) >> 2;
  60                         break;
  61
  62                 case htons(ETH_P_IPV6):
  63                         wlen += sizeof(struct ipv6hdr);
  64                         if (!pskb_may_pull(skb, wlen))
  65                                 goto err;
  66                         skb->priority = ipv6_get_dsfield(ipv6_hdr(skb)) >> 2;
  67                         break;
  68                 }
  69         }
  70         if (params->flags & SKBEDIT_F_QUEUE_MAPPING &&
  71             skb->dev->real_num_tx_queues > params->queue_mapping)
  72                 skb_set_queue_mapping(skb, params->queue_mapping);
  73         if (params->flags & SKBEDIT_F_MARK) {
  74                 skb->mark &= ~params->mask;
  75                 skb->mark |= params->mark & params->mask;
  76         }
  77         if (params->flags & SKBEDIT_F_PTYPE)
  78                 skb->pkt_type = params->ptype;
  79         return action;
  80
  81 err:
  82         qstats_drop_inc(this_cpu_ptr(d->common.cpu_qstats));
  83         return TC_ACT_SHOT;
  84 }
  85
  86 static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
  87         [TCA_SKBEDIT_PARMS]             = { .len = sizeof(struct tc_skbedit) },
  88         [TCA_SKBEDIT_PRIORITY]          = { .len = sizeof(u32) },
  89         [TCA_SKBEDIT_QUEUE_MAPPING]     = { .len = sizeof(u16) },
  90         [TCA_SKBEDIT_MARK]              = { .len = sizeof(u32) },
  91         [TCA_SKBEDIT_PTYPE]             = { .len = sizeof(u16) },
  92         [TCA_SKBEDIT_MASK]              = { .len = sizeof(u32) },
  93         [TCA_SKBEDIT_FLAGS]             = { .len = sizeof(u64) },
  94 };
  95
  96 static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
  97                             struct nlattr *est, struct tc_action **a,
  98                             int ovr, int bind, bool rtnl_held,
  99                             struct tcf_proto *tp,
 100                             struct netlink_ext_ack *extack)
 101 {
 102         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 103         struct tcf_skbedit_params *params_new;
 104         struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
 105         struct tc_skbedit *parm;
 106         struct tcf_skbedit *d;
 107         u32 flags = 0, *priority = NULL, *mark = NULL, *mask = NULL;
 108         u16 *queue_mapping = NULL, *ptype = NULL;
 109         bool exists = false;
 110         int ret = 0, err;
 111
 112         if (nla == NULL)
 113                 return -EINVAL;
 114
 115         err = nla_parse_nested(tb, TCA_SKBEDIT_MAX, nla, skbedit_policy, NULL);
 116         if (err < 0)
 117                 return err;
 118
 119         if (tb[TCA_SKBEDIT_PARMS] == NULL)
 120                 return -EINVAL;
 121
 122         if (tb[TCA_SKBEDIT_PRIORITY] != NULL) {
 123                 flags |= SKBEDIT_F_PRIORITY;
 124                 priority = nla_data(tb[TCA_SKBEDIT_PRIORITY]);
 125         }
 126
 127         if (tb[TCA_SKBEDIT_QUEUE_MAPPING] != NULL) {
 128                 flags |= SKBEDIT_F_QUEUE_MAPPING;
 129                 queue_mapping = nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING]);
 130         }
 131
 132         if (tb[TCA_SKBEDIT_PTYPE] != NULL) {
 133                 ptype = nla_data(tb[TCA_SKBEDIT_PTYPE]);
 134                 if (!skb_pkt_type_ok(*ptype))
 135                         return -EINVAL;
 136                 flags |= SKBEDIT_F_PTYPE;
 137         }
 138
 139         if (tb[TCA_SKBEDIT_MARK] != NULL) {
 140                 flags |= SKBEDIT_F_MARK;
 141                 mark = nla_data(tb[TCA_SKBEDIT_MARK]);
 142         }
 143
 144         if (tb[TCA_SKBEDIT_MASK] != NULL) {
 145                 flags |= SKBEDIT_F_MASK;
 146                 mask = nla_data(tb[TCA_SKBEDIT_MASK]);
 147         }
 148
 149         if (tb[TCA_SKBEDIT_FLAGS] != NULL) {
 150                 u64 *pure_flags = nla_data(tb[TCA_SKBEDIT_FLAGS]);
 151
 152                 if (*pure_flags & SKBEDIT_F_INHERITDSFIELD)
 153                         flags |= SKBEDIT_F_INHERITDSFIELD;
 154         }
 155
 156         parm = nla_data(tb[TCA_SKBEDIT_PARMS]);
 157
 158         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 159         if (err < 0)
 160                 return err;
 161         exists = err;
 162         if (exists && bind)
 163                 return 0;
 164
 165         if (!flags) {
 166                 if (exists)
 167                         tcf_idr_release(*a, bind);
 168                 else
 169                         tcf_idr_cleanup(tn, parm->index);
 170                 return -EINVAL;
 171         }
 172
 173         if (!exists) {
 174                 ret = tcf_idr_create(tn, parm->index, est, a,
 175                                      &act_skbedit_ops, bind, true);
 176                 if (ret) {
 177                         tcf_idr_cleanup(tn, parm->index);
 178                         return ret;
 179                 }
 180
 181                 d = to_skbedit(*a);
 182                 ret = ACT_P_CREATED;
 183         } else {
 184                 d = to_skbedit(*a);
 185                 if (!ovr) {
 186                         tcf_idr_release(*a, bind);
 187                         return -EEXIST;
 188                 }
 189         }
 190
 191         params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
 192         if (unlikely(!params_new)) {
 193                 tcf_idr_release(*a, bind);
 194                 return -ENOMEM;
 195         }
 196
 197         params_new->flags = flags;
 198         if (flags & SKBEDIT_F_PRIORITY)
 199                 params_new->priority = *priority;
 200         if (flags & SKBEDIT_F_QUEUE_MAPPING)
 201                 params_new->queue_mapping = *queue_mapping;
 202         if (flags & SKBEDIT_F_MARK)
 203                 params_new->mark = *mark;
 204         if (flags & SKBEDIT_F_PTYPE)
 205                 params_new->ptype = *ptype;
 206         /* default behaviour is to use all the bits */
 207         params_new->mask = 0xffffffff;
 208         if (flags & SKBEDIT_F_MASK)
 209                 params_new->mask = *mask;
 210
 211         spin_lock_bh(&d->tcf_lock);
 212         d->tcf_action = parm->action;
 213         rcu_swap_protected(d->params, params_new,
 214                            lockdep_is_held(&d->tcf_lock));
 215         spin_unlock_bh(&d->tcf_lock);
 216         if (params_new)
 217                 kfree_rcu(params_new, rcu);
 218
 219         if (ret == ACT_P_CREATED)
 220                 tcf_idr_insert(tn, *a);
 221         return ret;
 222 }
 223
 224 static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
 225                             int bind, int ref)
 226 {
 227         unsigned char *b = skb_tail_pointer(skb);
 228         struct tcf_skbedit *d = to_skbedit(a);
 229         struct tcf_skbedit_params *params;
 230         struct tc_skbedit opt = {
 231                 .index   = d->tcf_index,
 232                 .refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 233                 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
 234         };
 235         u64 pure_flags = 0;
 236         struct tcf_t t;
 237
 238         spin_lock_bh(&d->tcf_lock);
 239         params = rcu_dereference_protected(d->params,
 240                                            lockdep_is_held(&d->tcf_lock));
 241         opt.action = d->tcf_action;
 242
 243         if (nla_put(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt))
 244                 goto nla_put_failure;
 245         if ((params->flags & SKBEDIT_F_PRIORITY) &&
 246             nla_put_u32(skb, TCA_SKBEDIT_PRIORITY, params->priority))
 247                 goto nla_put_failure;
 248         if ((params->flags & SKBEDIT_F_QUEUE_MAPPING) &&
 249             nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING, params->queue_mapping))
 250                 goto nla_put_failure;
 251         if ((params->flags & SKBEDIT_F_MARK) &&
 252             nla_put_u32(skb, TCA_SKBEDIT_MARK, params->mark))
 253                 goto nla_put_failure;
 254         if ((params->flags & SKBEDIT_F_PTYPE) &&
 255             nla_put_u16(skb, TCA_SKBEDIT_PTYPE, params->ptype))
 256                 goto nla_put_failure;
 257         if ((params->flags & SKBEDIT_F_MASK) &&
 258             nla_put_u32(skb, TCA_SKBEDIT_MASK, params->mask))
 259                 goto nla_put_failure;
 260         if (params->flags & SKBEDIT_F_INHERITDSFIELD)
 261                 pure_flags |= SKBEDIT_F_INHERITDSFIELD;
 262         if (pure_flags != 0 &&
 263             nla_put(skb, TCA_SKBEDIT_FLAGS, sizeof(pure_flags), &pure_flags))
 264                 goto nla_put_failure;
 265
 266         tcf_tm_dump(&t, &d->tcf_tm);
 267         if (nla_put_64bit(skb, TCA_SKBEDIT_TM, sizeof(t), &t, TCA_SKBEDIT_PAD))
 268                 goto nla_put_failure;
 269         spin_unlock_bh(&d->tcf_lock);
 270
 271         return skb->len;
 272
 273 nla_put_failure:
 274         spin_unlock_bh(&d->tcf_lock);
 275         nlmsg_trim(skb, b);
 276         return -1;
 277 }
 278
 279 static void tcf_skbedit_cleanup(struct tc_action *a)
 280 {
 281         struct tcf_skbedit *d = to_skbedit(a);
 282         struct tcf_skbedit_params *params;
 283
 284         params = rcu_dereference_protected(d->params, 1);
 285         if (params)
 286                 kfree_rcu(params, rcu);
 287 }
 288
 289 static int tcf_skbedit_walker(struct net *net, struct sk_buff *skb,
 290                               struct netlink_callback *cb, int type,
 291                               const struct tc_action_ops *ops,
 292                               struct netlink_ext_ack *extack)
 293 {
 294         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 295
 296         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 297 }
 298
 299 static int tcf_skbedit_search(struct net *net, struct tc_action **a, u32 index)
 300 {
 301         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 302
 303         return tcf_idr_search(tn, a, index);
 304 }
 305
 306 static struct tc_action_ops act_skbedit_ops = {
 307         .kind           =       "skbedit",
 308         .id             =       TCA_ID_SKBEDIT,
 309         .owner          =       THIS_MODULE,
 310         .act            =       tcf_skbedit_act,
 311         .dump           =       tcf_skbedit_dump,
 312         .init           =       tcf_skbedit_init,
 313         .cleanup        =       tcf_skbedit_cleanup,
 314         .walk           =       tcf_skbedit_walker,
 315         .lookup         =       tcf_skbedit_search,
 316         .size           =       sizeof(struct tcf_skbedit),
 317 };
 318
 319 static __net_init int skbedit_init_net(struct net *net)
 320 {
 321         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 322
 323         return tc_action_net_init(tn, &act_skbedit_ops);
 324 }
 325
 326 static void __net_exit skbedit_exit_net(struct list_head *net_list)
 327 {
 328         tc_action_net_exit(net_list, skbedit_net_id);
 329 }
 330
 331 static struct pernet_operations skbedit_net_ops = {
 332         .init = skbedit_init_net,
 333         .exit_batch = skbedit_exit_net,
 334         .id   = &skbedit_net_id,
 335         .size = sizeof(struct tc_action_net),
 336 };
 337
 338 MODULE_AUTHOR("Alexander Duyck, <alexander.h.duyck@intel.com>");
 339 MODULE_DESCRIPTION("SKB Editing");
 340 MODULE_LICENSE("GPL");
 341
 342 static int __init skbedit_init_module(void)
 343 {
 344         return tcf_register_action(&act_skbedit_ops, &skbedit_net_ops);
 345 }
 346
 347 static void __exit skbedit_cleanup_module(void)
 348 {
 349         tcf_unregister_action(&act_skbedit_ops, &skbedit_net_ops);
 350 }
 351
 352 module_init(skbedit_init_module);
 353 module_exit(skbedit_cleanup_module);