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