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