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 #include <net/tc_wrapper.h>
  18
  19 static struct tc_action_ops act_mpls_ops;
  20
  21 #define ACT_MPLS_TTL_DEFAULT    255
  22
  23 static __be32 tcf_mpls_get_lse(struct mpls_shim_hdr *lse,
  24                                struct tcf_mpls_params *p, bool set_bos)
  25 {
  26         u32 new_lse = 0;
  27
  28         if (lse)
  29                 new_lse = be32_to_cpu(lse->label_stack_entry);
  30
  31         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET) {
  32                 new_lse &= ~MPLS_LS_LABEL_MASK;
  33                 new_lse |= p->tcfm_label << MPLS_LS_LABEL_SHIFT;
  34         }
  35         if (p->tcfm_ttl) {
  36                 new_lse &= ~MPLS_LS_TTL_MASK;
  37                 new_lse |= p->tcfm_ttl << MPLS_LS_TTL_SHIFT;
  38         }
  39         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET) {
  40                 new_lse &= ~MPLS_LS_TC_MASK;
  41                 new_lse |= p->tcfm_tc << MPLS_LS_TC_SHIFT;
  42         }
  43         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET) {
  44                 new_lse &= ~MPLS_LS_S_MASK;
  45                 new_lse |= p->tcfm_bos << MPLS_LS_S_SHIFT;
  46         } else if (set_bos) {
  47                 new_lse |= 1 << MPLS_LS_S_SHIFT;
  48         }
  49
  50         return cpu_to_be32(new_lse);
  51 }
  52
  53 TC_INDIRECT_SCOPE int tcf_mpls_act(struct sk_buff *skb,
  54                                    const struct tc_action *a,
  55                                    struct tcf_result *res)
  56 {
  57         struct tcf_mpls *m = to_mpls(a);
  58         struct tcf_mpls_params *p;
  59         __be32 new_lse;
  60         int ret, mac_len;
  61
  62         tcf_lastuse_update(&m->tcf_tm);
  63         bstats_update(this_cpu_ptr(m->common.cpu_bstats), skb);
  64
  65         /* Ensure 'data' points at mac_header prior calling mpls manipulating
  66          * functions.
  67          */
  68         if (skb_at_tc_ingress(skb)) {
  69                 skb_push_rcsum(skb, skb->mac_len);
  70                 mac_len = skb->mac_len;
  71         } else {
  72                 mac_len = skb_network_header(skb) - skb_mac_header(skb);
  73         }
  74
  75         ret = READ_ONCE(m->tcf_action);
  76
  77         p = rcu_dereference_bh(m->mpls_p);
  78
  79         switch (p->tcfm_action) {
  80         case TCA_MPLS_ACT_POP:
  81                 if (skb_mpls_pop(skb, p->tcfm_proto, mac_len,
  82                                  skb->dev && skb->dev->type == ARPHRD_ETHER))
  83                         goto drop;
  84                 break;
  85         case TCA_MPLS_ACT_PUSH:
  86                 new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb_protocol(skb, true)));
  87                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len,
  88                                   skb->dev && skb->dev->type == ARPHRD_ETHER))
  89                         goto drop;
  90                 break;
  91         case TCA_MPLS_ACT_MAC_PUSH:
  92                 if (skb_vlan_tag_present(skb)) {
  93                         if (__vlan_insert_inner_tag(skb, skb->vlan_proto,
  94                                                     skb_vlan_tag_get(skb),
  95                                                     ETH_HLEN) < 0)
  96                                 goto drop;
  97
  98                         skb->protocol = skb->vlan_proto;
  99                         __vlan_hwaccel_clear_tag(skb);
 100                 }
 101
 102                 new_lse = tcf_mpls_get_lse(NULL, p, mac_len ||
 103                                            !eth_p_mpls(skb->protocol));
 104
 105                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, 0, false))
 106                         goto drop;
 107                 break;
 108         case TCA_MPLS_ACT_MODIFY:
 109                 if (!pskb_may_pull(skb,
 110                                    skb_network_offset(skb) + MPLS_HLEN))
 111                         goto drop;
 112                 new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
 113                 if (skb_mpls_update_lse(skb, new_lse))
 114                         goto drop;
 115                 break;
 116         case TCA_MPLS_ACT_DEC_TTL:
 117                 if (skb_mpls_dec_ttl(skb))
 118                         goto drop;
 119                 break;
 120         }
 121
 122         if (skb_at_tc_ingress(skb))
 123                 skb_pull_rcsum(skb, skb->mac_len);
 124
 125         return ret;
 126
 127 drop:
 128         qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
 129         return TC_ACT_SHOT;
 130 }
 131
 132 static int valid_label(const struct nlattr *attr,
 133                        struct netlink_ext_ack *extack)
 134 {
 135         const u32 *label = nla_data(attr);
 136
 137         if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
 138                 NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
 139                 return -EINVAL;
 140         }
 141
 142         return 0;
 143 }
 144
 145 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
 146         [TCA_MPLS_PARMS]        = NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
 147         [TCA_MPLS_PROTO]        = { .type = NLA_U16 },
 148         [TCA_MPLS_LABEL]        = NLA_POLICY_VALIDATE_FN(NLA_U32, valid_label),
 149         [TCA_MPLS_TC]           = NLA_POLICY_RANGE(NLA_U8, 0, 7),
 150         [TCA_MPLS_TTL]          = NLA_POLICY_MIN(NLA_U8, 1),
 151         [TCA_MPLS_BOS]          = NLA_POLICY_RANGE(NLA_U8, 0, 1),
 152 };
 153
 154 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 155                          struct nlattr *est, struct tc_action **a,
 156                          struct tcf_proto *tp, u32 flags,
 157                          struct netlink_ext_ack *extack)
 158 {
 159         struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
 160         bool bind = flags & TCA_ACT_FLAGS_BIND;
 161         struct nlattr *tb[TCA_MPLS_MAX + 1];
 162         struct tcf_chain *goto_ch = NULL;
 163         struct tcf_mpls_params *p;
 164         struct tc_mpls *parm;
 165         bool exists = false;
 166         struct tcf_mpls *m;
 167         int ret = 0, err;
 168         u8 mpls_ttl = 0;
 169         u32 index;
 170
 171         if (!nla) {
 172                 NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
 173                 return -EINVAL;
 174         }
 175
 176         err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
 177         if (err < 0)
 178                 return err;
 179
 180         if (!tb[TCA_MPLS_PARMS]) {
 181                 NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
 182                 return -EINVAL;
 183         }
 184         parm = nla_data(tb[TCA_MPLS_PARMS]);
 185         index = parm->index;
 186
 187         /* Verify parameters against action type. */
 188         switch (parm->m_action) {
 189         case TCA_MPLS_ACT_POP:
 190                 if (!tb[TCA_MPLS_PROTO]) {
 191                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
 192                         return -EINVAL;
 193                 }
 194                 if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 195                         NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
 196                         return -EINVAL;
 197                 }
 198                 if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
 199                     tb[TCA_MPLS_BOS]) {
 200                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
 201                         return -EINVAL;
 202                 }
 203                 break;
 204         case TCA_MPLS_ACT_DEC_TTL:
 205                 if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
 206                     tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
 207                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
 208                         return -EINVAL;
 209                 }
 210                 break;
 211         case TCA_MPLS_ACT_PUSH:
 212         case TCA_MPLS_ACT_MAC_PUSH:
 213                 if (!tb[TCA_MPLS_LABEL]) {
 214                         NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
 215                         return -EINVAL;
 216                 }
 217                 if (tb[TCA_MPLS_PROTO] &&
 218                     !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 219                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
 220                         return -EPROTONOSUPPORT;
 221                 }
 222                 /* Push needs a TTL - if not specified, set a default value. */
 223                 if (!tb[TCA_MPLS_TTL]) {
 224 #if IS_ENABLED(CONFIG_MPLS)
 225                         mpls_ttl = net->mpls.default_ttl ?
 226                                    net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
 227 #else
 228                         mpls_ttl = ACT_MPLS_TTL_DEFAULT;
 229 #endif
 230                 }
 231                 break;
 232         case TCA_MPLS_ACT_MODIFY:
 233                 if (tb[TCA_MPLS_PROTO]) {
 234                         NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
 235                         return -EINVAL;
 236                 }
 237                 break;
 238         default:
 239                 NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
 240                 return -EINVAL;
 241         }
 242
 243         err = tcf_idr_check_alloc(tn, &index, a, bind);
 244         if (err < 0)
 245                 return err;
 246         exists = err;
 247         if (exists && bind)
 248                 return 0;
 249
 250         if (!exists) {
 251                 ret = tcf_idr_create(tn, index, est, a,
 252                                      &act_mpls_ops, bind, true, flags);
 253                 if (ret) {
 254                         tcf_idr_cleanup(tn, index);
 255                         return ret;
 256                 }
 257
 258                 ret = ACT_P_CREATED;
 259         } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 260                 tcf_idr_release(*a, bind);
 261                 return -EEXIST;
 262         }
 263
 264         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 265         if (err < 0)
 266                 goto release_idr;
 267
 268         m = to_mpls(*a);
 269
 270         p = kzalloc(sizeof(*p), GFP_KERNEL);
 271         if (!p) {
 272                 err = -ENOMEM;
 273                 goto put_chain;
 274         }
 275
 276         p->tcfm_action = parm->m_action;
 277         p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
 278                                              ACT_MPLS_LABEL_NOT_SET;
 279         p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
 280                                        ACT_MPLS_TC_NOT_SET;
 281         p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
 282                                          mpls_ttl;
 283         p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
 284                                          ACT_MPLS_BOS_NOT_SET;
 285         p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
 286                                              htons(ETH_P_MPLS_UC);
 287
 288         spin_lock_bh(&m->tcf_lock);
 289         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 290         p = rcu_replace_pointer(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
 291         spin_unlock_bh(&m->tcf_lock);
 292
 293         if (goto_ch)
 294                 tcf_chain_put_by_act(goto_ch);
 295         if (p)
 296                 kfree_rcu(p, rcu);
 297
 298         return ret;
 299 put_chain:
 300         if (goto_ch)
 301                 tcf_chain_put_by_act(goto_ch);
 302 release_idr:
 303         tcf_idr_release(*a, bind);
 304         return err;
 305 }
 306
 307 static void tcf_mpls_cleanup(struct tc_action *a)
 308 {
 309         struct tcf_mpls *m = to_mpls(a);
 310         struct tcf_mpls_params *p;
 311
 312         p = rcu_dereference_protected(m->mpls_p, 1);
 313         if (p)
 314                 kfree_rcu(p, rcu);
 315 }
 316
 317 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
 318                          int bind, int ref)
 319 {
 320         unsigned char *b = skb_tail_pointer(skb);
 321         struct tcf_mpls *m = to_mpls(a);
 322         struct tcf_mpls_params *p;
 323         struct tc_mpls opt = {
 324                 .index    = m->tcf_index,
 325                 .refcnt   = refcount_read(&m->tcf_refcnt) - ref,
 326                 .bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
 327         };
 328         struct tcf_t t;
 329
 330         spin_lock_bh(&m->tcf_lock);
 331         opt.action = m->tcf_action;
 332         p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
 333         opt.m_action = p->tcfm_action;
 334
 335         if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
 336                 goto nla_put_failure;
 337
 338         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
 339             nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
 340                 goto nla_put_failure;
 341
 342         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
 343             nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
 344                 goto nla_put_failure;
 345
 346         if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
 347                 goto nla_put_failure;
 348
 349         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
 350             nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
 351                 goto nla_put_failure;
 352
 353         if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
 354                 goto nla_put_failure;
 355
 356         tcf_tm_dump(&t, &m->tcf_tm);
 357
 358         if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
 359                 goto nla_put_failure;
 360
 361         spin_unlock_bh(&m->tcf_lock);
 362
 363         return skb->len;
 364
 365 nla_put_failure:
 366         spin_unlock_bh(&m->tcf_lock);
 367         nlmsg_trim(skb, b);
 368         return -EMSGSIZE;
 369 }
 370
 371 static int tcf_mpls_offload_act_setup(struct tc_action *act, void *entry_data,
 372                                       u32 *index_inc, bool bind,
 373                                       struct netlink_ext_ack *extack)
 374 {
 375         if (bind) {
 376                 struct flow_action_entry *entry = entry_data;
 377
 378                 switch (tcf_mpls_action(act)) {
 379                 case TCA_MPLS_ACT_PUSH:
 380                         entry->id = FLOW_ACTION_MPLS_PUSH;
 381                         entry->mpls_push.proto = tcf_mpls_proto(act);
 382                         entry->mpls_push.label = tcf_mpls_label(act);
 383                         entry->mpls_push.tc = tcf_mpls_tc(act);
 384                         entry->mpls_push.bos = tcf_mpls_bos(act);
 385                         entry->mpls_push.ttl = tcf_mpls_ttl(act);
 386                         break;
 387                 case TCA_MPLS_ACT_POP:
 388                         entry->id = FLOW_ACTION_MPLS_POP;
 389                         entry->mpls_pop.proto = tcf_mpls_proto(act);
 390                         break;
 391                 case TCA_MPLS_ACT_MODIFY:
 392                         entry->id = FLOW_ACTION_MPLS_MANGLE;
 393                         entry->mpls_mangle.label = tcf_mpls_label(act);
 394                         entry->mpls_mangle.tc = tcf_mpls_tc(act);
 395                         entry->mpls_mangle.bos = tcf_mpls_bos(act);
 396                         entry->mpls_mangle.ttl = tcf_mpls_ttl(act);
 397                         break;
 398                 case TCA_MPLS_ACT_DEC_TTL:
 399                         NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"dec_ttl\" option is used");
 400                         return -EOPNOTSUPP;
 401                 case TCA_MPLS_ACT_MAC_PUSH:
 402                         NL_SET_ERR_MSG_MOD(extack, "Offload not supported when \"mac_push\" option is used");
 403                         return -EOPNOTSUPP;
 404                 default:
 405                         NL_SET_ERR_MSG_MOD(extack, "Unsupported MPLS mode offload");
 406                         return -EOPNOTSUPP;
 407                 }
 408                 *index_inc = 1;
 409         } else {
 410                 struct flow_offload_action *fl_action = entry_data;
 411
 412                 switch (tcf_mpls_action(act)) {
 413                 case TCA_MPLS_ACT_PUSH:
 414                         fl_action->id = FLOW_ACTION_MPLS_PUSH;
 415                         break;
 416                 case TCA_MPLS_ACT_POP:
 417                         fl_action->id = FLOW_ACTION_MPLS_POP;
 418                         break;
 419                 case TCA_MPLS_ACT_MODIFY:
 420                         fl_action->id = FLOW_ACTION_MPLS_MANGLE;
 421                         break;
 422                 default:
 423                         return -EOPNOTSUPP;
 424                 }
 425         }
 426
 427         return 0;
 428 }
 429
 430 static struct tc_action_ops act_mpls_ops = {
 431         .kind           =       "mpls",
 432         .id             =       TCA_ID_MPLS,
 433         .owner          =       THIS_MODULE,
 434         .act            =       tcf_mpls_act,
 435         .dump           =       tcf_mpls_dump,
 436         .init           =       tcf_mpls_init,
 437         .cleanup        =       tcf_mpls_cleanup,
 438         .offload_act_setup =    tcf_mpls_offload_act_setup,
 439         .size           =       sizeof(struct tcf_mpls),
 440 };
 441
 442 static __net_init int mpls_init_net(struct net *net)
 443 {
 444         struct tc_action_net *tn = net_generic(net, act_mpls_ops.net_id);
 445
 446         return tc_action_net_init(net, tn, &act_mpls_ops);
 447 }
 448
 449 static void __net_exit mpls_exit_net(struct list_head *net_list)
 450 {
 451         tc_action_net_exit(net_list, act_mpls_ops.net_id);
 452 }
 453
 454 static struct pernet_operations mpls_net_ops = {
 455         .init = mpls_init_net,
 456         .exit_batch = mpls_exit_net,
 457         .id   = &act_mpls_ops.net_id,
 458         .size = sizeof(struct tc_action_net),
 459 };
 460
 461 static int __init mpls_init_module(void)
 462 {
 463         return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
 464 }
 465
 466 static void __exit mpls_cleanup_module(void)
 467 {
 468         tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
 469 }
 470
 471 module_init(mpls_init_module);
 472 module_exit(mpls_cleanup_module);
 473
 474 MODULE_SOFTDEP("post: mpls_gso");
 475 MODULE_AUTHOR("Netronome Systems <[email protected]>");
 476 MODULE_LICENSE("GPL");
 477 MODULE_DESCRIPTION("MPLS manipulation actions");