net/sched/act_mpls.c

   1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
   2 /* Copyright (C) 2019 Netronome Systems, Inc. */
   3
   4 #include <linux/init.h>
   5 #include <linux/kernel.h>
   6 #include <linux/module.h>
   7 #include <linux/mpls.h>
   8 #include <linux/rtnetlink.h>
   9 #include <linux/skbuff.h>
  10 #include <linux/tc_act/tc_mpls.h>
  11 #include <net/mpls.h>
  12 #include <net/netlink.h>
  13 #include <net/pkt_sched.h>
  14 #include <net/pkt_cls.h>
  15 #include <net/tc_act/tc_mpls.h>
  16
  17 static unsigned int mpls_net_id;
  18 static struct tc_action_ops act_mpls_ops;
  19
  20 #define ACT_MPLS_TTL_DEFAULT    255
  21
  22 static __be32 tcf_mpls_get_lse(struct mpls_shim_hdr *lse,
  23                                struct tcf_mpls_params *p, bool set_bos)
  24 {
  25         u32 new_lse = 0;
  26
  27         if (lse)
  28                 new_lse = be32_to_cpu(lse->label_stack_entry);
  29
  30         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET) {
  31                 new_lse &= ~MPLS_LS_LABEL_MASK;
  32                 new_lse |= p->tcfm_label << MPLS_LS_LABEL_SHIFT;
  33         }
  34         if (p->tcfm_ttl) {
  35                 new_lse &= ~MPLS_LS_TTL_MASK;
  36                 new_lse |= p->tcfm_ttl << MPLS_LS_TTL_SHIFT;
  37         }
  38         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET) {
  39                 new_lse &= ~MPLS_LS_TC_MASK;
  40                 new_lse |= p->tcfm_tc << MPLS_LS_TC_SHIFT;
  41         }
  42         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET) {
  43                 new_lse &= ~MPLS_LS_S_MASK;
  44                 new_lse |= p->tcfm_bos << MPLS_LS_S_SHIFT;
  45         } else if (set_bos) {
  46                 new_lse |= 1 << MPLS_LS_S_SHIFT;
  47         }
  48
  49         return cpu_to_be32(new_lse);
  50 }
  51
  52 static int tcf_mpls_act(struct sk_buff *skb, const struct tc_action *a,
  53                         struct tcf_result *res)
  54 {
  55         struct tcf_mpls *m = to_mpls(a);
  56         struct tcf_mpls_params *p;
  57         __be32 new_lse;
  58         int ret;
  59
  60         tcf_lastuse_update(&m->tcf_tm);
  61         bstats_cpu_update(this_cpu_ptr(m->common.cpu_bstats), skb);
  62
  63         /* Ensure 'data' points at mac_header prior calling mpls manipulating
  64          * functions.
  65          */
  66         if (skb_at_tc_ingress(skb))
  67                 skb_push_rcsum(skb, skb->mac_len);
  68
  69         ret = READ_ONCE(m->tcf_action);
  70
  71         p = rcu_dereference_bh(m->mpls_p);
  72
  73         switch (p->tcfm_action) {
  74         case TCA_MPLS_ACT_POP:
  75                 if (skb_mpls_pop(skb, p->tcfm_proto))
  76                         goto drop;
  77                 break;
  78         case TCA_MPLS_ACT_PUSH:
  79                 new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb->protocol));
  80                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto))
  81                         goto drop;
  82                 break;
  83         case TCA_MPLS_ACT_MODIFY:
  84                 new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
  85                 if (skb_mpls_update_lse(skb, new_lse))
  86                         goto drop;
  87                 break;
  88         case TCA_MPLS_ACT_DEC_TTL:
  89                 if (skb_mpls_dec_ttl(skb))
  90                         goto drop;
  91                 break;
  92         }
  93
  94         if (skb_at_tc_ingress(skb))
  95                 skb_pull_rcsum(skb, skb->mac_len);
  96
  97         return ret;
  98
  99 drop:
 100         qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
 101         return TC_ACT_SHOT;
 102 }
 103
 104 static int valid_label(const struct nlattr *attr,
 105                        struct netlink_ext_ack *extack)
 106 {
 107         const u32 *label = nla_data(attr);
 108
 109         if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
 110                 NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
 111                 return -EINVAL;
 112         }
 113
 114         return 0;
 115 }
 116
 117 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
 118         [TCA_MPLS_UNSPEC]       = { .strict_start_type = TCA_MPLS_UNSPEC + 1 },
 119         [TCA_MPLS_PARMS]        = NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
 120         [TCA_MPLS_PROTO]        = { .type = NLA_U16 },
 121         [TCA_MPLS_LABEL]        = NLA_POLICY_VALIDATE_FN(NLA_U32, valid_label),
 122         [TCA_MPLS_TC]           = NLA_POLICY_RANGE(NLA_U8, 0, 7),
 123         [TCA_MPLS_TTL]          = NLA_POLICY_MIN(NLA_U8, 1),
 124         [TCA_MPLS_BOS]          = NLA_POLICY_RANGE(NLA_U8, 0, 1),
 125 };
 126
 127 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 128                          struct nlattr *est, struct tc_action **a,
 129                          int ovr, int bind, bool rtnl_held,
 130                          struct tcf_proto *tp, struct netlink_ext_ack *extack)
 131 {
 132         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 133         struct nlattr *tb[TCA_MPLS_MAX + 1];
 134         struct tcf_chain *goto_ch = NULL;
 135         struct tcf_mpls_params *p;
 136         struct tc_mpls *parm;
 137         bool exists = false;
 138         struct tcf_mpls *m;
 139         int ret = 0, err;
 140         u8 mpls_ttl = 0;
 141         u32 index;
 142
 143         if (!nla) {
 144                 NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
 145                 return -EINVAL;
 146         }
 147
 148         err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
 149         if (err < 0)
 150                 return err;
 151
 152         if (!tb[TCA_MPLS_PARMS]) {
 153                 NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
 154                 return -EINVAL;
 155         }
 156         parm = nla_data(tb[TCA_MPLS_PARMS]);
 157         index = parm->index;
 158
 159         /* Verify parameters against action type. */
 160         switch (parm->m_action) {
 161         case TCA_MPLS_ACT_POP:
 162                 if (!tb[TCA_MPLS_PROTO]) {
 163                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
 164                         return -EINVAL;
 165                 }
 166                 if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 167                         NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
 168                         return -EINVAL;
 169                 }
 170                 if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
 171                     tb[TCA_MPLS_BOS]) {
 172                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
 173                         return -EINVAL;
 174                 }
 175                 break;
 176         case TCA_MPLS_ACT_DEC_TTL:
 177                 if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
 178                     tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
 179                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
 180                         return -EINVAL;
 181                 }
 182                 break;
 183         case TCA_MPLS_ACT_PUSH:
 184                 if (!tb[TCA_MPLS_LABEL]) {
 185                         NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
 186                         return -EINVAL;
 187                 }
 188                 if (tb[TCA_MPLS_PROTO] &&
 189                     !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 190                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
 191                         return -EPROTONOSUPPORT;
 192                 }
 193                 /* Push needs a TTL - if not specified, set a default value. */
 194                 if (!tb[TCA_MPLS_TTL]) {
 195 #if IS_ENABLED(CONFIG_MPLS)
 196                         mpls_ttl = net->mpls.default_ttl ?
 197                                    net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
 198 #else
 199                         mpls_ttl = ACT_MPLS_TTL_DEFAULT;
 200 #endif
 201                 }
 202                 break;
 203         case TCA_MPLS_ACT_MODIFY:
 204                 if (tb[TCA_MPLS_PROTO]) {
 205                         NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
 206                         return -EINVAL;
 207                 }
 208                 break;
 209         default:
 210                 NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
 211                 return -EINVAL;
 212         }
 213
 214         err = tcf_idr_check_alloc(tn, &index, a, bind);
 215         if (err < 0)
 216                 return err;
 217         exists = err;
 218         if (exists && bind)
 219                 return 0;
 220
 221         if (!exists) {
 222                 ret = tcf_idr_create(tn, index, est, a,
 223                                      &act_mpls_ops, bind, true);
 224                 if (ret) {
 225                         tcf_idr_cleanup(tn, index);
 226                         return ret;
 227                 }
 228
 229                 ret = ACT_P_CREATED;
 230         } else if (!ovr) {
 231                 tcf_idr_release(*a, bind);
 232                 return -EEXIST;
 233         }
 234
 235         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 236         if (err < 0)
 237                 goto release_idr;
 238
 239         m = to_mpls(*a);
 240
 241         p = kzalloc(sizeof(*p), GFP_KERNEL);
 242         if (!p) {
 243                 err = -ENOMEM;
 244                 goto put_chain;
 245         }
 246
 247         p->tcfm_action = parm->m_action;
 248         p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
 249                                              ACT_MPLS_LABEL_NOT_SET;
 250         p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
 251                                        ACT_MPLS_TC_NOT_SET;
 252         p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
 253                                          mpls_ttl;
 254         p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
 255                                          ACT_MPLS_BOS_NOT_SET;
 256         p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
 257                                              htons(ETH_P_MPLS_UC);
 258
 259         spin_lock_bh(&m->tcf_lock);
 260         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 261         rcu_swap_protected(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
 262         spin_unlock_bh(&m->tcf_lock);
 263
 264         if (goto_ch)
 265                 tcf_chain_put_by_act(goto_ch);
 266         if (p)
 267                 kfree_rcu(p, rcu);
 268
 269         if (ret == ACT_P_CREATED)
 270                 tcf_idr_insert(tn, *a);
 271         return ret;
 272 put_chain:
 273         if (goto_ch)
 274                 tcf_chain_put_by_act(goto_ch);
 275 release_idr:
 276         tcf_idr_release(*a, bind);
 277         return err;
 278 }
 279
 280 static void tcf_mpls_cleanup(struct tc_action *a)
 281 {
 282         struct tcf_mpls *m = to_mpls(a);
 283         struct tcf_mpls_params *p;
 284
 285         p = rcu_dereference_protected(m->mpls_p, 1);
 286         if (p)
 287                 kfree_rcu(p, rcu);
 288 }
 289
 290 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
 291                          int bind, int ref)
 292 {
 293         unsigned char *b = skb_tail_pointer(skb);
 294         struct tcf_mpls *m = to_mpls(a);
 295         struct tcf_mpls_params *p;
 296         struct tc_mpls opt = {
 297                 .index    = m->tcf_index,
 298                 .refcnt   = refcount_read(&m->tcf_refcnt) - ref,
 299                 .bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
 300         };
 301         struct tcf_t t;
 302
 303         spin_lock_bh(&m->tcf_lock);
 304         opt.action = m->tcf_action;
 305         p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
 306         opt.m_action = p->tcfm_action;
 307
 308         if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
 309                 goto nla_put_failure;
 310
 311         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
 312             nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
 313                 goto nla_put_failure;
 314
 315         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
 316             nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
 317                 goto nla_put_failure;
 318
 319         if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
 320                 goto nla_put_failure;
 321
 322         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
 323             nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
 324                 goto nla_put_failure;
 325
 326         if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
 327                 goto nla_put_failure;
 328
 329         tcf_tm_dump(&t, &m->tcf_tm);
 330
 331         if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
 332                 goto nla_put_failure;
 333
 334         spin_unlock_bh(&m->tcf_lock);
 335
 336         return skb->len;
 337
 338 nla_put_failure:
 339         spin_unlock_bh(&m->tcf_lock);
 340         nlmsg_trim(skb, b);
 341         return -EMSGSIZE;
 342 }
 343
 344 static int tcf_mpls_walker(struct net *net, struct sk_buff *skb,
 345                            struct netlink_callback *cb, int type,
 346                            const struct tc_action_ops *ops,
 347                            struct netlink_ext_ack *extack)
 348 {
 349         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 350
 351         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 352 }
 353
 354 static int tcf_mpls_search(struct net *net, struct tc_action **a, u32 index)
 355 {
 356         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 357
 358         return tcf_idr_search(tn, a, index);
 359 }
 360
 361 static struct tc_action_ops act_mpls_ops = {
 362         .kind           =       "mpls",
 363         .id             =       TCA_ID_MPLS,
 364         .owner          =       THIS_MODULE,
 365         .act            =       tcf_mpls_act,
 366         .dump           =       tcf_mpls_dump,
 367         .init           =       tcf_mpls_init,
 368         .cleanup        =       tcf_mpls_cleanup,
 369         .walk           =       tcf_mpls_walker,
 370         .lookup         =       tcf_mpls_search,
 371         .size           =       sizeof(struct tcf_mpls),
 372 };
 373
 374 static __net_init int mpls_init_net(struct net *net)
 375 {
 376         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 377
 378         return tc_action_net_init(tn, &act_mpls_ops);
 379 }
 380
 381 static void __net_exit mpls_exit_net(struct list_head *net_list)
 382 {
 383         tc_action_net_exit(net_list, mpls_net_id);
 384 }
 385
 386 static struct pernet_operations mpls_net_ops = {
 387         .init = mpls_init_net,
 388         .exit_batch = mpls_exit_net,
 389         .id   = &mpls_net_id,
 390         .size = sizeof(struct tc_action_net),
 391 };
 392
 393 static int __init mpls_init_module(void)
 394 {
 395         return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
 396 }
 397
 398 static void __exit mpls_cleanup_module(void)
 399 {
 400         tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
 401 }
 402
 403 module_init(mpls_init_module);
 404 module_exit(mpls_cleanup_module);
 405
 406 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
 407 MODULE_LICENSE("GPL");
 408 MODULE_DESCRIPTION("MPLS manipulation actions");