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/if_arp.h>
   5 #include <linux/init.h>
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/mpls.h>
   9 #include <linux/rtnetlink.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/tc_act/tc_mpls.h>
  12 #include <net/mpls.h>
  13 #include <net/netlink.h>
  14 #include <net/pkt_sched.h>
  15 #include <net/pkt_cls.h>
  16 #include <net/tc_act/tc_mpls.h>
  17
  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, mac_len;
  59
  60         tcf_lastuse_update(&m->tcf_tm);
  61         bstats_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                 mac_len = skb->mac_len;
  69         } else {
  70                 mac_len = skb_network_header(skb) - skb_mac_header(skb);
  71         }
  72
  73         ret = READ_ONCE(m->tcf_action);
  74
  75         p = rcu_dereference_bh(m->mpls_p);
  76
  77         switch (p->tcfm_action) {
  78         case TCA_MPLS_ACT_POP:
  79                 if (skb_mpls_pop(skb, p->tcfm_proto, mac_len,
  80                                  skb->dev && skb->dev->type == ARPHRD_ETHER))
  81                         goto drop;
  82                 break;
  83         case TCA_MPLS_ACT_PUSH:
  84                 new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb_protocol(skb, true)));
  85                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len,
  86                                   skb->dev && skb->dev->type == ARPHRD_ETHER))
  87                         goto drop;
  88                 break;
  89         case TCA_MPLS_ACT_MAC_PUSH:
  90                 if (skb_vlan_tag_present(skb)) {
  91                         if (__vlan_insert_inner_tag(skb, skb->vlan_proto,
  92                                                     skb_vlan_tag_get(skb),
  93                                                     ETH_HLEN) < 0)
  94                                 goto drop;
  95
  96                         skb->protocol = skb->vlan_proto;
  97                         __vlan_hwaccel_clear_tag(skb);
  98                 }
  99
 100                 new_lse = tcf_mpls_get_lse(NULL, p, mac_len ||
 101                                            !eth_p_mpls(skb->protocol));
 102
 103                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, 0, false))
 104                         goto drop;
 105                 break;
 106         case TCA_MPLS_ACT_MODIFY:
 107                 if (!pskb_may_pull(skb,
 108                                    skb_network_offset(skb) + MPLS_HLEN))
 109                         goto drop;
 110                 new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
 111                 if (skb_mpls_update_lse(skb, new_lse))
 112                         goto drop;
 113                 break;
 114         case TCA_MPLS_ACT_DEC_TTL:
 115                 if (skb_mpls_dec_ttl(skb))
 116                         goto drop;
 117                 break;
 118         }
 119
 120         if (skb_at_tc_ingress(skb))
 121                 skb_pull_rcsum(skb, skb->mac_len);
 122
 123         return ret;
 124
 125 drop:
 126         qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
 127         return TC_ACT_SHOT;
 128 }
 129
 130 static int valid_label(const struct nlattr *attr,
 131                        struct netlink_ext_ack *extack)
 132 {
 133         const u32 *label = nla_data(attr);
 134
 135         if (nla_len(attr) != sizeof(*label)) {
 136                 NL_SET_ERR_MSG_MOD(extack, "Invalid MPLS label length");
 137                 return -EINVAL;
 138         }
 139
 140         if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
 141                 NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
 142                 return -EINVAL;
 143         }
 144
 145         return 0;
 146 }
 147
 148 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
 149         [TCA_MPLS_PARMS]        = NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
 150         [TCA_MPLS_PROTO]        = { .type = NLA_U16 },
 151         [TCA_MPLS_LABEL]        = NLA_POLICY_VALIDATE_FN(NLA_BINARY,
 152                                                          valid_label),
 153         [TCA_MPLS_TC]           = NLA_POLICY_RANGE(NLA_U8, 0, 7),
 154         [TCA_MPLS_TTL]          = NLA_POLICY_MIN(NLA_U8, 1),
 155         [TCA_MPLS_BOS]          = NLA_POLICY_RANGE(NLA_U8, 0, 1),
 156 };
 157
 158 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 159                          struct nlattr *est, struct tc_action **a,
 160                          struct tcf_proto *tp, u32 flags,
 161                          struct netlink_ext_ack *extack)
 162 {
 163         struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
 164         bool bind = flags & TCA_ACT_FLAGS_BIND;
 165         struct nlattr *tb[TCA_MPLS_MAX + 1];
 166         struct tcf_chain *goto_ch = NULL;
 167         struct tcf_mpls_params *p;
 168         struct tc_mpls *parm;
 169         bool exists = false;
 170         struct tcf_mpls *m;
 171         int ret = 0, err;
 172         u8 mpls_ttl = 0;
 173         u32 index;
 174
 175         if (!nla) {
 176                 NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
 177                 return -EINVAL;
 178         }
 179
 180         err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
 181         if (err < 0)
 182                 return err;
 183
 184         if (!tb[TCA_MPLS_PARMS]) {
 185                 NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
 186                 return -EINVAL;
 187         }
 188         parm = nla_data(tb[TCA_MPLS_PARMS]);
 189         index = parm->index;
 190
 191         err = tcf_idr_check_alloc(tn, &index, a, bind);
 192         if (err < 0)
 193                 return err;
 194         exists = err;
 195         if (exists && bind)
 196                 return 0;
 197
 198         if (!exists) {
 199                 ret = tcf_idr_create(tn, index, est, a, &act_mpls_ops, bind,
 200                                      true, flags);
 201                 if (ret) {
 202                         tcf_idr_cleanup(tn, index);
 203                         return ret;
 204                 }
 205
 206                 ret = ACT_P_CREATED;
 207         } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 208                 tcf_idr_release(*a, bind);
 209                 return -EEXIST;
 210         }
 211
 212         /* Verify parameters against action type. */
 213         switch (parm->m_action) {
 214         case TCA_MPLS_ACT_POP:
 215                 if (!tb[TCA_MPLS_PROTO]) {
 216                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
 217                         err = -EINVAL;
 218                         goto release_idr;
 219                 }
 220                 if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 221                         NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
 222                         err = -EINVAL;
 223                         goto release_idr;
 224                 }
 225                 if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
 226                     tb[TCA_MPLS_BOS]) {
 227                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
 228                         err = -EINVAL;
 229                         goto release_idr;
 230                 }
 231                 break;
 232         case TCA_MPLS_ACT_DEC_TTL:
 233                 if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
 234                     tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
 235                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
 236                         err = -EINVAL;
 237                         goto release_idr;
 238                 }
 239                 break;
 240         case TCA_MPLS_ACT_PUSH:
 241         case TCA_MPLS_ACT_MAC_PUSH:
 242                 if (!tb[TCA_MPLS_LABEL]) {
 243                         NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
 244                         err = -EINVAL;
 245                         goto release_idr;
 246                 }
 247                 if (tb[TCA_MPLS_PROTO] &&
 248                     !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 249                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
 250                         err = -EPROTONOSUPPORT;
 251                         goto release_idr;
 252                 }
 253                 /* Push needs a TTL - if not specified, set a default value. */
 254                 if (!tb[TCA_MPLS_TTL]) {
 255 #if IS_ENABLED(CONFIG_MPLS)
 256                         mpls_ttl = net->mpls.default_ttl ?
 257                                    net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
 258 #else
 259                         mpls_ttl = ACT_MPLS_TTL_DEFAULT;
 260 #endif
 261                 }
 262                 break;
 263         case TCA_MPLS_ACT_MODIFY:
 264                 if (tb[TCA_MPLS_PROTO]) {
 265                         NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
 266                         err = -EINVAL;
 267                         goto release_idr;
 268                 }
 269                 break;
 270         default:
 271                 NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
 272                 err = -EINVAL;
 273                 goto release_idr;
 274         }
 275
 276         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 277         if (err < 0)
 278                 goto release_idr;
 279
 280         m = to_mpls(*a);
 281
 282         p = kzalloc(sizeof(*p), GFP_KERNEL);
 283         if (!p) {
 284                 err = -ENOMEM;
 285                 goto put_chain;
 286         }
 287
 288         p->tcfm_action = parm->m_action;
 289         p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
 290                                              ACT_MPLS_LABEL_NOT_SET;
 291         p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
 292                                        ACT_MPLS_TC_NOT_SET;
 293         p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
 294                                          mpls_ttl;
 295         p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
 296                                          ACT_MPLS_BOS_NOT_SET;
 297         p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
 298                                              htons(ETH_P_MPLS_UC);
 299
 300         spin_lock_bh(&m->tcf_lock);
 301         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 302         p = rcu_replace_pointer(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
 303         spin_unlock_bh(&m->tcf_lock);
 304
 305         if (goto_ch)
 306                 tcf_chain_put_by_act(goto_ch);
 307         if (p)
 308                 kfree_rcu(p, rcu);
 309
 310         return ret;
 311 put_chain:
 312         if (goto_ch)
 313                 tcf_chain_put_by_act(goto_ch);
 314 release_idr:
 315         tcf_idr_release(*a, bind);
 316         return err;
 317 }
 318
 319 static void tcf_mpls_cleanup(struct tc_action *a)
 320 {
 321         struct tcf_mpls *m = to_mpls(a);
 322         struct tcf_mpls_params *p;
 323
 324         p = rcu_dereference_protected(m->mpls_p, 1);
 325         if (p)
 326                 kfree_rcu(p, rcu);
 327 }
 328
 329 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
 330                          int bind, int ref)
 331 {
 332         unsigned char *b = skb_tail_pointer(skb);
 333         struct tcf_mpls *m = to_mpls(a);
 334         struct tcf_mpls_params *p;
 335         struct tc_mpls opt = {
 336                 .index    = m->tcf_index,
 337                 .refcnt   = refcount_read(&m->tcf_refcnt) - ref,
 338                 .bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
 339         };
 340         struct tcf_t t;
 341
 342         spin_lock_bh(&m->tcf_lock);
 343         opt.action = m->tcf_action;
 344         p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
 345         opt.m_action = p->tcfm_action;
 346
 347         if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
 348                 goto nla_put_failure;
 349
 350         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
 351             nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
 352                 goto nla_put_failure;
 353
 354         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
 355             nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
 356                 goto nla_put_failure;
 357
 358         if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
 359                 goto nla_put_failure;
 360
 361         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
 362             nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
 363                 goto nla_put_failure;
 364
 365         if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
 366                 goto nla_put_failure;
 367
 368         tcf_tm_dump(&t, &m->tcf_tm);
 369
 370         if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
 371                 goto nla_put_failure;
 372
 373         spin_unlock_bh(&m->tcf_lock);
 374
 375         return skb->len;
 376
 377 nla_put_failure:
 378         spin_unlock_bh(&m->tcf_lock);
 379         nlmsg_trim(skb, b);
 380         return -EMSGSIZE;
 381 }
 382
 383 static int tcf_mpls_offload_act_setup(struct tc_action *act, void *entry_data,
 384                                       u32 *index_inc, bool bind,
 385                                       struct netlink_ext_ack *extack)
 386 {
 387         if (bind) {
 388                 struct flow_action_entry *entry = entry_data;
 389
 390                 switch (tcf_mpls_action(act)) {
 391                 case TCA_MPLS_ACT_PUSH:
 392                         entry->id = FLOW_ACTION_MPLS_PUSH;
 393                         entry->mpls_push.proto = tcf_mpls_proto(act);
 394                         entry->mpls_push.label = tcf_mpls_label(act);
 395                         entry->mpls_push.tc = tcf_mpls_tc(act);
 396                         entry->mpls_push.bos = tcf_mpls_bos(act);
 397                         entry->mpls_push.ttl = tcf_mpls_ttl(act);
 398                         break;
 399                 case TCA_MPLS_ACT_POP:
 400                         entry->id = FLOW_ACTION_MPLS_POP;
 401                         entry->mpls_pop.proto = tcf_mpls_proto(act);
 402                         break;
 403                 case TCA_MPLS_ACT_MODIFY:
 404                         entry->id = FLOW_ACTION_MPLS_MANGLE;
 405                         entry->mpls_mangle.label = tcf_mpls_label(act);
 406                         entry->mpls_mangle.tc = tcf_mpls_tc(act);
 407                         entry->mpls_mangle.bos = tcf_mpls_bos(act);
 408                         entry->mpls_mangle.ttl = tcf_mpls_ttl(act);
 409                         break;
 410                 case TCA_MPLS_ACT_DEC_TTL:
 411                         NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"dec_ttl\" option is used");
 412                         return -EOPNOTSUPP;
 413                 case TCA_MPLS_ACT_MAC_PUSH:
 414                         NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"mac_push\" option is used");
 415                         return -EOPNOTSUPP;
 416                 default:
 417                         NL_SET_ERR_MSG_MOD(extack, "Unsupported MPLS mode offload");
 418                         return -EOPNOTSUPP;
 419                 }
 420                 *index_inc = 1;
 421         } else {
 422                 struct flow_offload_action *fl_action = entry_data;
 423
 424                 switch (tcf_mpls_action(act)) {
 425                 case TCA_MPLS_ACT_PUSH:
 426                         fl_action->id = FLOW_ACTION_MPLS_PUSH;
 427                         break;
 428                 case TCA_MPLS_ACT_POP:
 429                         fl_action->id = FLOW_ACTION_MPLS_POP;
 430                         break;
 431                 case TCA_MPLS_ACT_MODIFY:
 432                         fl_action->id = FLOW_ACTION_MPLS_MANGLE;
 433                         break;
 434                 default:
 435                         return -EOPNOTSUPP;
 436                 }
 437         }
 438
 439         return 0;
 440 }
 441
 442 static struct tc_action_ops act_mpls_ops = {
 443         .kind           =       "mpls",
 444         .id             =       TCA_ID_MPLS,
 445         .owner          =       THIS_MODULE,
 446         .act            =       tcf_mpls_act,
 447         .dump           =       tcf_mpls_dump,
 448         .init           =       tcf_mpls_init,
 449         .cleanup        =       tcf_mpls_cleanup,
 450         .offload_act_setup =    tcf_mpls_offload_act_setup,
 451         .size           =       sizeof(struct tcf_mpls),
 452 };
 453
 454 static __net_init int mpls_init_net(struct net *net)
 455 {
 456         struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
 457
 458         return tc_action_net_init(net, tn, &act_mpls_ops);
 459 }
 460
 461 static void __net_exit mpls_exit_net(struct list_head *net_list)
 462 {
 463         tc_action_net_exit(net_list, act_mpls_ops.net_id);
 464 }
 465
 466 static struct pernet_operations mpls_net_ops = {
 467         .init = mpls_init_net,
 468         .exit_batch = mpls_exit_net,
 469         .id   = &act_mpls_ops.net_id,
 470         .size = sizeof(struct tc_action_net),
 471 };
 472
 473 static int __init mpls_init_module(void)
 474 {
 475         return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
 476 }
 477
 478 static void __exit mpls_cleanup_module(void)
 479 {
 480         tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
 481 }
 482
 483 module_init(mpls_init_module);
 484 module_exit(mpls_cleanup_module);
 485
 486 MODULE_SOFTDEP("post: mpls_gso");
 487 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
 488 MODULE_LICENSE("GPL");
 489 MODULE_DESCRIPTION("MPLS manipulation actions");