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, mac_len;
  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                 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                         goto drop;
  81                 break;
  82         case TCA_MPLS_ACT_PUSH:
  83                 new_lse = tcf_mpls_get_lse(NULL, p, !eth_p_mpls(skb->protocol));
  84                 if (skb_mpls_push(skb, new_lse, p->tcfm_proto, mac_len))
  85                         goto drop;
  86                 break;
  87         case TCA_MPLS_ACT_MODIFY:
  88                 new_lse = tcf_mpls_get_lse(mpls_hdr(skb), p, false);
  89                 if (skb_mpls_update_lse(skb, new_lse))
  90                         goto drop;
  91                 break;
  92         case TCA_MPLS_ACT_DEC_TTL:
  93                 if (skb_mpls_dec_ttl(skb))
  94                         goto drop;
  95                 break;
  96         }
  97
  98         if (skb_at_tc_ingress(skb))
  99                 skb_pull_rcsum(skb, skb->mac_len);
 100
 101         return ret;
 102
 103 drop:
 104         qstats_drop_inc(this_cpu_ptr(m->common.cpu_qstats));
 105         return TC_ACT_SHOT;
 106 }
 107
 108 static int valid_label(const struct nlattr *attr,
 109                        struct netlink_ext_ack *extack)
 110 {
 111         const u32 *label = nla_data(attr);
 112
 113         if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
 114                 NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
 115                 return -EINVAL;
 116         }
 117
 118         return 0;
 119 }
 120
 121 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
 122         [TCA_MPLS_UNSPEC]       = { .strict_start_type = TCA_MPLS_UNSPEC + 1 },
 123         [TCA_MPLS_PARMS]        = NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
 124         [TCA_MPLS_PROTO]        = { .type = NLA_U16 },
 125         [TCA_MPLS_LABEL]        = NLA_POLICY_VALIDATE_FN(NLA_U32, valid_label),
 126         [TCA_MPLS_TC]           = NLA_POLICY_RANGE(NLA_U8, 0, 7),
 127         [TCA_MPLS_TTL]          = NLA_POLICY_MIN(NLA_U8, 1),
 128         [TCA_MPLS_BOS]          = NLA_POLICY_RANGE(NLA_U8, 0, 1),
 129 };
 130
 131 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 132                          struct nlattr *est, struct tc_action **a,
 133                          int ovr, int bind, bool rtnl_held,
 134                          struct tcf_proto *tp, struct netlink_ext_ack *extack)
 135 {
 136         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 137         struct nlattr *tb[TCA_MPLS_MAX + 1];
 138         struct tcf_chain *goto_ch = NULL;
 139         struct tcf_mpls_params *p;
 140         struct tc_mpls *parm;
 141         bool exists = false;
 142         struct tcf_mpls *m;
 143         int ret = 0, err;
 144         u8 mpls_ttl = 0;
 145         u32 index;
 146
 147         if (!nla) {
 148                 NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
 149                 return -EINVAL;
 150         }
 151
 152         err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
 153         if (err < 0)
 154                 return err;
 155
 156         if (!tb[TCA_MPLS_PARMS]) {
 157                 NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
 158                 return -EINVAL;
 159         }
 160         parm = nla_data(tb[TCA_MPLS_PARMS]);
 161         index = parm->index;
 162
 163         /* Verify parameters against action type. */
 164         switch (parm->m_action) {
 165         case TCA_MPLS_ACT_POP:
 166                 if (!tb[TCA_MPLS_PROTO]) {
 167                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
 168                         return -EINVAL;
 169                 }
 170                 if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 171                         NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
 172                         return -EINVAL;
 173                 }
 174                 if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
 175                     tb[TCA_MPLS_BOS]) {
 176                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
 177                         return -EINVAL;
 178                 }
 179                 break;
 180         case TCA_MPLS_ACT_DEC_TTL:
 181                 if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
 182                     tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
 183                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
 184                         return -EINVAL;
 185                 }
 186                 break;
 187         case TCA_MPLS_ACT_PUSH:
 188                 if (!tb[TCA_MPLS_LABEL]) {
 189                         NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
 190                         return -EINVAL;
 191                 }
 192                 if (tb[TCA_MPLS_PROTO] &&
 193                     !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 194                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
 195                         return -EPROTONOSUPPORT;
 196                 }
 197                 /* Push needs a TTL - if not specified, set a default value. */
 198                 if (!tb[TCA_MPLS_TTL]) {
 199 #if IS_ENABLED(CONFIG_MPLS)
 200                         mpls_ttl = net->mpls.default_ttl ?
 201                                    net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
 202 #else
 203                         mpls_ttl = ACT_MPLS_TTL_DEFAULT;
 204 #endif
 205                 }
 206                 break;
 207         case TCA_MPLS_ACT_MODIFY:
 208                 if (tb[TCA_MPLS_PROTO]) {
 209                         NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
 210                         return -EINVAL;
 211                 }
 212                 break;
 213         default:
 214                 NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
 215                 return -EINVAL;
 216         }
 217
 218         err = tcf_idr_check_alloc(tn, &index, a, bind);
 219         if (err < 0)
 220                 return err;
 221         exists = err;
 222         if (exists && bind)
 223                 return 0;
 224
 225         if (!exists) {
 226                 ret = tcf_idr_create(tn, index, est, a,
 227                                      &act_mpls_ops, bind, true);
 228                 if (ret) {
 229                         tcf_idr_cleanup(tn, index);
 230                         return ret;
 231                 }
 232
 233                 ret = ACT_P_CREATED;
 234         } else if (!ovr) {
 235                 tcf_idr_release(*a, bind);
 236                 return -EEXIST;
 237         }
 238
 239         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 240         if (err < 0)
 241                 goto release_idr;
 242
 243         m = to_mpls(*a);
 244
 245         p = kzalloc(sizeof(*p), GFP_KERNEL);
 246         if (!p) {
 247                 err = -ENOMEM;
 248                 goto put_chain;
 249         }
 250
 251         p->tcfm_action = parm->m_action;
 252         p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
 253                                              ACT_MPLS_LABEL_NOT_SET;
 254         p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
 255                                        ACT_MPLS_TC_NOT_SET;
 256         p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
 257                                          mpls_ttl;
 258         p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
 259                                          ACT_MPLS_BOS_NOT_SET;
 260         p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
 261                                              htons(ETH_P_MPLS_UC);
 262
 263         spin_lock_bh(&m->tcf_lock);
 264         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 265         rcu_swap_protected(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
 266         spin_unlock_bh(&m->tcf_lock);
 267
 268         if (goto_ch)
 269                 tcf_chain_put_by_act(goto_ch);
 270         if (p)
 271                 kfree_rcu(p, rcu);
 272
 273         if (ret == ACT_P_CREATED)
 274                 tcf_idr_insert(tn, *a);
 275         return ret;
 276 put_chain:
 277         if (goto_ch)
 278                 tcf_chain_put_by_act(goto_ch);
 279 release_idr:
 280         tcf_idr_release(*a, bind);
 281         return err;
 282 }
 283
 284 static void tcf_mpls_cleanup(struct tc_action *a)
 285 {
 286         struct tcf_mpls *m = to_mpls(a);
 287         struct tcf_mpls_params *p;
 288
 289         p = rcu_dereference_protected(m->mpls_p, 1);
 290         if (p)
 291                 kfree_rcu(p, rcu);
 292 }
 293
 294 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
 295                          int bind, int ref)
 296 {
 297         unsigned char *b = skb_tail_pointer(skb);
 298         struct tcf_mpls *m = to_mpls(a);
 299         struct tcf_mpls_params *p;
 300         struct tc_mpls opt = {
 301                 .index    = m->tcf_index,
 302                 .refcnt   = refcount_read(&m->tcf_refcnt) - ref,
 303                 .bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
 304         };
 305         struct tcf_t t;
 306
 307         spin_lock_bh(&m->tcf_lock);
 308         opt.action = m->tcf_action;
 309         p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
 310         opt.m_action = p->tcfm_action;
 311
 312         if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
 313                 goto nla_put_failure;
 314
 315         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
 316             nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
 317                 goto nla_put_failure;
 318
 319         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
 320             nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
 321                 goto nla_put_failure;
 322
 323         if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
 324                 goto nla_put_failure;
 325
 326         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
 327             nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
 328                 goto nla_put_failure;
 329
 330         if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
 331                 goto nla_put_failure;
 332
 333         tcf_tm_dump(&t, &m->tcf_tm);
 334
 335         if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
 336                 goto nla_put_failure;
 337
 338         spin_unlock_bh(&m->tcf_lock);
 339
 340         return skb->len;
 341
 342 nla_put_failure:
 343         spin_unlock_bh(&m->tcf_lock);
 344         nlmsg_trim(skb, b);
 345         return -EMSGSIZE;
 346 }
 347
 348 static int tcf_mpls_walker(struct net *net, struct sk_buff *skb,
 349                            struct netlink_callback *cb, int type,
 350                            const struct tc_action_ops *ops,
 351                            struct netlink_ext_ack *extack)
 352 {
 353         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 354
 355         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 356 }
 357
 358 static int tcf_mpls_search(struct net *net, struct tc_action **a, u32 index)
 359 {
 360         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 361
 362         return tcf_idr_search(tn, a, index);
 363 }
 364
 365 static struct tc_action_ops act_mpls_ops = {
 366         .kind           =       "mpls",
 367         .id             =       TCA_ID_MPLS,
 368         .owner          =       THIS_MODULE,
 369         .act            =       tcf_mpls_act,
 370         .dump           =       tcf_mpls_dump,
 371         .init           =       tcf_mpls_init,
 372         .cleanup        =       tcf_mpls_cleanup,
 373         .walk           =       tcf_mpls_walker,
 374         .lookup         =       tcf_mpls_search,
 375         .size           =       sizeof(struct tcf_mpls),
 376 };
 377
 378 static __net_init int mpls_init_net(struct net *net)
 379 {
 380         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 381
 382         return tc_action_net_init(net, tn, &act_mpls_ops);
 383 }
 384
 385 static void __net_exit mpls_exit_net(struct list_head *net_list)
 386 {
 387         tc_action_net_exit(net_list, mpls_net_id);
 388 }
 389
 390 static struct pernet_operations mpls_net_ops = {
 391         .init = mpls_init_net,
 392         .exit_batch = mpls_exit_net,
 393         .id   = &mpls_net_id,
 394         .size = sizeof(struct tc_action_net),
 395 };
 396
 397 static int __init mpls_init_module(void)
 398 {
 399         return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
 400 }
 401
 402 static void __exit mpls_cleanup_module(void)
 403 {
 404         tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
 405 }
 406
 407 module_init(mpls_init_module);
 408 module_exit(mpls_cleanup_module);
 409
 410 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
 411 MODULE_LICENSE("GPL");
 412 MODULE_DESCRIPTION("MPLS manipulation actions");