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 netlink_ext_ack *extack)
 100 {
 101         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 102         struct tcf_skbedit_params *params_new;
 103         struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
 104         struct tc_skbedit *parm;
 105         struct tcf_skbedit *d;
 106         u32 flags = 0, *priority = NULL, *mark = NULL, *mask = NULL;
 107         u16 *queue_mapping = NULL, *ptype = NULL;
 108         bool exists = false;
 109         int ret = 0, err;
 110
 111         if (nla == NULL)
 112                 return -EINVAL;
 113
 114         err = nla_parse_nested(tb, TCA_SKBEDIT_MAX, nla, skbedit_policy, NULL);
 115         if (err < 0)
 116                 return err;
 117
 118         if (tb[TCA_SKBEDIT_PARMS] == NULL)
 119                 return -EINVAL;
 120
 121         if (tb[TCA_SKBEDIT_PRIORITY] != NULL) {
 122                 flags |= SKBEDIT_F_PRIORITY;
 123                 priority = nla_data(tb[TCA_SKBEDIT_PRIORITY]);
 124         }
 125
 126         if (tb[TCA_SKBEDIT_QUEUE_MAPPING] != NULL) {
 127                 flags |= SKBEDIT_F_QUEUE_MAPPING;
 128                 queue_mapping = nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING]);
 129         }
 130
 131         if (tb[TCA_SKBEDIT_PTYPE] != NULL) {
 132                 ptype = nla_data(tb[TCA_SKBEDIT_PTYPE]);
 133                 if (!skb_pkt_type_ok(*ptype))
 134                         return -EINVAL;
 135                 flags |= SKBEDIT_F_PTYPE;
 136         }
 137
 138         if (tb[TCA_SKBEDIT_MARK] != NULL) {
 139                 flags |= SKBEDIT_F_MARK;
 140                 mark = nla_data(tb[TCA_SKBEDIT_MARK]);
 141         }
 142
 143         if (tb[TCA_SKBEDIT_MASK] != NULL) {
 144                 flags |= SKBEDIT_F_MASK;
 145                 mask = nla_data(tb[TCA_SKBEDIT_MASK]);
 146         }
 147
 148         if (tb[TCA_SKBEDIT_FLAGS] != NULL) {
 149                 u64 *pure_flags = nla_data(tb[TCA_SKBEDIT_FLAGS]);
 150
 151                 if (*pure_flags & SKBEDIT_F_INHERITDSFIELD)
 152                         flags |= SKBEDIT_F_INHERITDSFIELD;
 153         }
 154
 155         parm = nla_data(tb[TCA_SKBEDIT_PARMS]);
 156
 157         err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
 158         if (err < 0)
 159                 return err;
 160         exists = err;
 161         if (exists && bind)
 162                 return 0;
 163
 164         if (!flags) {
 165                 if (exists)
 166                         tcf_idr_release(*a, bind);
 167                 else
 168                         tcf_idr_cleanup(tn, parm->index);
 169                 return -EINVAL;
 170         }
 171
 172         if (!exists) {
 173                 ret = tcf_idr_create(tn, parm->index, est, a,
 174                                      &act_skbedit_ops, bind, true);
 175                 if (ret) {
 176                         tcf_idr_cleanup(tn, parm->index);
 177                         return ret;
 178                 }
 179
 180                 d = to_skbedit(*a);
 181                 ret = ACT_P_CREATED;
 182         } else {
 183                 d = to_skbedit(*a);
 184                 if (!ovr) {
 185                         tcf_idr_release(*a, bind);
 186                         return -EEXIST;
 187                 }
 188         }
 189
 190         params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
 191         if (unlikely(!params_new)) {
 192                 tcf_idr_release(*a, bind);
 193                 return -ENOMEM;
 194         }
 195
 196         params_new->flags = flags;
 197         if (flags & SKBEDIT_F_PRIORITY)
 198                 params_new->priority = *priority;
 199         if (flags & SKBEDIT_F_QUEUE_MAPPING)
 200                 params_new->queue_mapping = *queue_mapping;
 201         if (flags & SKBEDIT_F_MARK)
 202                 params_new->mark = *mark;
 203         if (flags & SKBEDIT_F_PTYPE)
 204                 params_new->ptype = *ptype;
 205         /* default behaviour is to use all the bits */
 206         params_new->mask = 0xffffffff;
 207         if (flags & SKBEDIT_F_MASK)
 208                 params_new->mask = *mask;
 209
 210         spin_lock_bh(&d->tcf_lock);
 211         d->tcf_action = parm->action;
 212         rcu_swap_protected(d->params, params_new,
 213                            lockdep_is_held(&d->tcf_lock));
 214         spin_unlock_bh(&d->tcf_lock);
 215         if (params_new)
 216                 kfree_rcu(params_new, rcu);
 217
 218         if (ret == ACT_P_CREATED)
 219                 tcf_idr_insert(tn, *a);
 220         return ret;
 221 }
 222
 223 static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
 224                             int bind, int ref)
 225 {
 226         unsigned char *b = skb_tail_pointer(skb);
 227         struct tcf_skbedit *d = to_skbedit(a);
 228         struct tcf_skbedit_params *params;
 229         struct tc_skbedit opt = {
 230                 .index   = d->tcf_index,
 231                 .refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 232                 .bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
 233         };
 234         u64 pure_flags = 0;
 235         struct tcf_t t;
 236
 237         spin_lock_bh(&d->tcf_lock);
 238         params = rcu_dereference_protected(d->params,
 239                                            lockdep_is_held(&d->tcf_lock));
 240         opt.action = d->tcf_action;
 241
 242         if (nla_put(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt))
 243                 goto nla_put_failure;
 244         if ((params->flags & SKBEDIT_F_PRIORITY) &&
 245             nla_put_u32(skb, TCA_SKBEDIT_PRIORITY, params->priority))
 246                 goto nla_put_failure;
 247         if ((params->flags & SKBEDIT_F_QUEUE_MAPPING) &&
 248             nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING, params->queue_mapping))
 249                 goto nla_put_failure;
 250         if ((params->flags & SKBEDIT_F_MARK) &&
 251             nla_put_u32(skb, TCA_SKBEDIT_MARK, params->mark))
 252                 goto nla_put_failure;
 253         if ((params->flags & SKBEDIT_F_PTYPE) &&
 254             nla_put_u16(skb, TCA_SKBEDIT_PTYPE, params->ptype))
 255                 goto nla_put_failure;
 256         if ((params->flags & SKBEDIT_F_MASK) &&
 257             nla_put_u32(skb, TCA_SKBEDIT_MASK, params->mask))
 258                 goto nla_put_failure;
 259         if (params->flags & SKBEDIT_F_INHERITDSFIELD)
 260                 pure_flags |= SKBEDIT_F_INHERITDSFIELD;
 261         if (pure_flags != 0 &&
 262             nla_put(skb, TCA_SKBEDIT_FLAGS, sizeof(pure_flags), &pure_flags))
 263                 goto nla_put_failure;
 264
 265         tcf_tm_dump(&t, &d->tcf_tm);
 266         if (nla_put_64bit(skb, TCA_SKBEDIT_TM, sizeof(t), &t, TCA_SKBEDIT_PAD))
 267                 goto nla_put_failure;
 268         spin_unlock_bh(&d->tcf_lock);
 269
 270         return skb->len;
 271
 272 nla_put_failure:
 273         spin_unlock_bh(&d->tcf_lock);
 274         nlmsg_trim(skb, b);
 275         return -1;
 276 }
 277
 278 static void tcf_skbedit_cleanup(struct tc_action *a)
 279 {
 280         struct tcf_skbedit *d = to_skbedit(a);
 281         struct tcf_skbedit_params *params;
 282
 283         params = rcu_dereference_protected(d->params, 1);
 284         if (params)
 285                 kfree_rcu(params, rcu);
 286 }
 287
 288 static int tcf_skbedit_walker(struct net *net, struct sk_buff *skb,
 289                               struct netlink_callback *cb, int type,
 290                               const struct tc_action_ops *ops,
 291                               struct netlink_ext_ack *extack)
 292 {
 293         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 294
 295         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 296 }
 297
 298 static int tcf_skbedit_search(struct net *net, struct tc_action **a, u32 index)
 299 {
 300         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 301
 302         return tcf_idr_search(tn, a, index);
 303 }
 304
 305 static struct tc_action_ops act_skbedit_ops = {
 306         .kind           =       "skbedit",
 307         .id             =       TCA_ID_SKBEDIT,
 308         .owner          =       THIS_MODULE,
 309         .act            =       tcf_skbedit_act,
 310         .dump           =       tcf_skbedit_dump,
 311         .init           =       tcf_skbedit_init,
 312         .cleanup        =       tcf_skbedit_cleanup,
 313         .walk           =       tcf_skbedit_walker,
 314         .lookup         =       tcf_skbedit_search,
 315         .size           =       sizeof(struct tcf_skbedit),
 316 };
 317
 318 static __net_init int skbedit_init_net(struct net *net)
 319 {
 320         struct tc_action_net *tn = net_generic(net, skbedit_net_id);
 321
 322         return tc_action_net_init(tn, &act_skbedit_ops);
 323 }
 324
 325 static void __net_exit skbedit_exit_net(struct list_head *net_list)
 326 {
 327         tc_action_net_exit(net_list, skbedit_net_id);
 328 }
 329
 330 static struct pernet_operations skbedit_net_ops = {
 331         .init = skbedit_init_net,
 332         .exit_batch = skbedit_exit_net,
 333         .id   = &skbedit_net_id,
 334         .size = sizeof(struct tc_action_net),
 335 };
 336
 337 MODULE_AUTHOR("Alexander Duyck, <alexander.h.duyck@intel.com>");
 338 MODULE_DESCRIPTION("SKB Editing");
 339 MODULE_LICENSE("GPL");
 340
 341 static int __init skbedit_init_module(void)
 342 {
 343         return tcf_register_action(&act_skbedit_ops, &skbedit_net_ops);
 344 }
 345
 346 static void __exit skbedit_cleanup_module(void)
 347 {
 348         tcf_unregister_action(&act_skbedit_ops, &skbedit_net_ops);
 349 }
 350
 351 module_init(skbedit_init_module);
 352 module_exit(skbedit_cleanup_module);