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 (nla_len(attr) != sizeof(*label)) {
 137                 NL_SET_ERR_MSG_MOD(extack, "Invalid MPLS label length");
 138                 return -EINVAL;
 139         }
 140
 141         if (*label & ~MPLS_LABEL_MASK || *label == MPLS_LABEL_IMPLNULL) {
 142                 NL_SET_ERR_MSG_MOD(extack, "MPLS label out of range");
 143                 return -EINVAL;
 144         }
 145
 146         return 0;
 147 }
 148
 149 static const struct nla_policy mpls_policy[TCA_MPLS_MAX + 1] = {
 150         [TCA_MPLS_PARMS]        = NLA_POLICY_EXACT_LEN(sizeof(struct tc_mpls)),
 151         [TCA_MPLS_PROTO]        = { .type = NLA_U16 },
 152         [TCA_MPLS_LABEL]        = NLA_POLICY_VALIDATE_FN(NLA_BINARY,
 153                                                          valid_label),
 154         [TCA_MPLS_TC]           = NLA_POLICY_RANGE(NLA_U8, 0, 7),
 155         [TCA_MPLS_TTL]          = NLA_POLICY_MIN(NLA_U8, 1),
 156         [TCA_MPLS_BOS]          = NLA_POLICY_RANGE(NLA_U8, 0, 1),
 157 };
 158
 159 static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 160                          struct nlattr *est, struct tc_action **a,
 161                          int ovr, int bind, bool rtnl_held,
 162                          struct tcf_proto *tp, u32 flags,
 163                          struct netlink_ext_ack *extack)
 164 {
 165         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 166         struct nlattr *tb[TCA_MPLS_MAX + 1];
 167         struct tcf_chain *goto_ch = NULL;
 168         struct tcf_mpls_params *p;
 169         struct tc_mpls *parm;
 170         bool exists = false;
 171         struct tcf_mpls *m;
 172         int ret = 0, err;
 173         u8 mpls_ttl = 0;
 174         u32 index;
 175
 176         if (!nla) {
 177                 NL_SET_ERR_MSG_MOD(extack, "Missing netlink attributes");
 178                 return -EINVAL;
 179         }
 180
 181         err = nla_parse_nested(tb, TCA_MPLS_MAX, nla, mpls_policy, extack);
 182         if (err < 0)
 183                 return err;
 184
 185         if (!tb[TCA_MPLS_PARMS]) {
 186                 NL_SET_ERR_MSG_MOD(extack, "No MPLS params");
 187                 return -EINVAL;
 188         }
 189         parm = nla_data(tb[TCA_MPLS_PARMS]);
 190         index = parm->index;
 191
 192         /* Verify parameters against action type. */
 193         switch (parm->m_action) {
 194         case TCA_MPLS_ACT_POP:
 195                 if (!tb[TCA_MPLS_PROTO]) {
 196                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be set for MPLS pop");
 197                         return -EINVAL;
 198                 }
 199                 if (!eth_proto_is_802_3(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 200                         NL_SET_ERR_MSG_MOD(extack, "Invalid protocol type for MPLS pop");
 201                         return -EINVAL;
 202                 }
 203                 if (tb[TCA_MPLS_LABEL] || tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] ||
 204                     tb[TCA_MPLS_BOS]) {
 205                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC or BOS cannot be used with MPLS pop");
 206                         return -EINVAL;
 207                 }
 208                 break;
 209         case TCA_MPLS_ACT_DEC_TTL:
 210                 if (tb[TCA_MPLS_PROTO] || tb[TCA_MPLS_LABEL] ||
 211                     tb[TCA_MPLS_TTL] || tb[TCA_MPLS_TC] || tb[TCA_MPLS_BOS]) {
 212                         NL_SET_ERR_MSG_MOD(extack, "Label, TTL, TC, BOS or protocol cannot be used with MPLS dec_ttl");
 213                         return -EINVAL;
 214                 }
 215                 break;
 216         case TCA_MPLS_ACT_PUSH:
 217         case TCA_MPLS_ACT_MAC_PUSH:
 218                 if (!tb[TCA_MPLS_LABEL]) {
 219                         NL_SET_ERR_MSG_MOD(extack, "Label is required for MPLS push");
 220                         return -EINVAL;
 221                 }
 222                 if (tb[TCA_MPLS_PROTO] &&
 223                     !eth_p_mpls(nla_get_be16(tb[TCA_MPLS_PROTO]))) {
 224                         NL_SET_ERR_MSG_MOD(extack, "Protocol must be an MPLS type for MPLS push");
 225                         return -EPROTONOSUPPORT;
 226                 }
 227                 /* Push needs a TTL - if not specified, set a default value. */
 228                 if (!tb[TCA_MPLS_TTL]) {
 229 #if IS_ENABLED(CONFIG_MPLS)
 230                         mpls_ttl = net->mpls.default_ttl ?
 231                                    net->mpls.default_ttl : ACT_MPLS_TTL_DEFAULT;
 232 #else
 233                         mpls_ttl = ACT_MPLS_TTL_DEFAULT;
 234 #endif
 235                 }
 236                 break;
 237         case TCA_MPLS_ACT_MODIFY:
 238                 if (tb[TCA_MPLS_PROTO]) {
 239                         NL_SET_ERR_MSG_MOD(extack, "Protocol cannot be used with MPLS modify");
 240                         return -EINVAL;
 241                 }
 242                 break;
 243         default:
 244                 NL_SET_ERR_MSG_MOD(extack, "Unknown MPLS action");
 245                 return -EINVAL;
 246         }
 247
 248         err = tcf_idr_check_alloc(tn, &index, a, bind);
 249         if (err < 0)
 250                 return err;
 251         exists = err;
 252         if (exists && bind)
 253                 return 0;
 254
 255         if (!exists) {
 256                 ret = tcf_idr_create(tn, index, est, a,
 257                                      &act_mpls_ops, bind, true, flags);
 258                 if (ret) {
 259                         tcf_idr_cleanup(tn, index);
 260                         return ret;
 261                 }
 262
 263                 ret = ACT_P_CREATED;
 264         } else if (!ovr) {
 265                 tcf_idr_release(*a, bind);
 266                 return -EEXIST;
 267         }
 268
 269         err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 270         if (err < 0)
 271                 goto release_idr;
 272
 273         m = to_mpls(*a);
 274
 275         p = kzalloc(sizeof(*p), GFP_KERNEL);
 276         if (!p) {
 277                 err = -ENOMEM;
 278                 goto put_chain;
 279         }
 280
 281         p->tcfm_action = parm->m_action;
 282         p->tcfm_label = tb[TCA_MPLS_LABEL] ? nla_get_u32(tb[TCA_MPLS_LABEL]) :
 283                                              ACT_MPLS_LABEL_NOT_SET;
 284         p->tcfm_tc = tb[TCA_MPLS_TC] ? nla_get_u8(tb[TCA_MPLS_TC]) :
 285                                        ACT_MPLS_TC_NOT_SET;
 286         p->tcfm_ttl = tb[TCA_MPLS_TTL] ? nla_get_u8(tb[TCA_MPLS_TTL]) :
 287                                          mpls_ttl;
 288         p->tcfm_bos = tb[TCA_MPLS_BOS] ? nla_get_u8(tb[TCA_MPLS_BOS]) :
 289                                          ACT_MPLS_BOS_NOT_SET;
 290         p->tcfm_proto = tb[TCA_MPLS_PROTO] ? nla_get_be16(tb[TCA_MPLS_PROTO]) :
 291                                              htons(ETH_P_MPLS_UC);
 292
 293         spin_lock_bh(&m->tcf_lock);
 294         goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 295         p = rcu_replace_pointer(m->mpls_p, p, lockdep_is_held(&m->tcf_lock));
 296         spin_unlock_bh(&m->tcf_lock);
 297
 298         if (goto_ch)
 299                 tcf_chain_put_by_act(goto_ch);
 300         if (p)
 301                 kfree_rcu(p, rcu);
 302
 303         return ret;
 304 put_chain:
 305         if (goto_ch)
 306                 tcf_chain_put_by_act(goto_ch);
 307 release_idr:
 308         tcf_idr_release(*a, bind);
 309         return err;
 310 }
 311
 312 static void tcf_mpls_cleanup(struct tc_action *a)
 313 {
 314         struct tcf_mpls *m = to_mpls(a);
 315         struct tcf_mpls_params *p;
 316
 317         p = rcu_dereference_protected(m->mpls_p, 1);
 318         if (p)
 319                 kfree_rcu(p, rcu);
 320 }
 321
 322 static int tcf_mpls_dump(struct sk_buff *skb, struct tc_action *a,
 323                          int bind, int ref)
 324 {
 325         unsigned char *b = skb_tail_pointer(skb);
 326         struct tcf_mpls *m = to_mpls(a);
 327         struct tcf_mpls_params *p;
 328         struct tc_mpls opt = {
 329                 .index    = m->tcf_index,
 330                 .refcnt   = refcount_read(&m->tcf_refcnt) - ref,
 331                 .bindcnt  = atomic_read(&m->tcf_bindcnt) - bind,
 332         };
 333         struct tcf_t t;
 334
 335         spin_lock_bh(&m->tcf_lock);
 336         opt.action = m->tcf_action;
 337         p = rcu_dereference_protected(m->mpls_p, lockdep_is_held(&m->tcf_lock));
 338         opt.m_action = p->tcfm_action;
 339
 340         if (nla_put(skb, TCA_MPLS_PARMS, sizeof(opt), &opt))
 341                 goto nla_put_failure;
 342
 343         if (p->tcfm_label != ACT_MPLS_LABEL_NOT_SET &&
 344             nla_put_u32(skb, TCA_MPLS_LABEL, p->tcfm_label))
 345                 goto nla_put_failure;
 346
 347         if (p->tcfm_tc != ACT_MPLS_TC_NOT_SET &&
 348             nla_put_u8(skb, TCA_MPLS_TC, p->tcfm_tc))
 349                 goto nla_put_failure;
 350
 351         if (p->tcfm_ttl && nla_put_u8(skb, TCA_MPLS_TTL, p->tcfm_ttl))
 352                 goto nla_put_failure;
 353
 354         if (p->tcfm_bos != ACT_MPLS_BOS_NOT_SET &&
 355             nla_put_u8(skb, TCA_MPLS_BOS, p->tcfm_bos))
 356                 goto nla_put_failure;
 357
 358         if (nla_put_be16(skb, TCA_MPLS_PROTO, p->tcfm_proto))
 359                 goto nla_put_failure;
 360
 361         tcf_tm_dump(&t, &m->tcf_tm);
 362
 363         if (nla_put_64bit(skb, TCA_MPLS_TM, sizeof(t), &t, TCA_MPLS_PAD))
 364                 goto nla_put_failure;
 365
 366         spin_unlock_bh(&m->tcf_lock);
 367
 368         return skb->len;
 369
 370 nla_put_failure:
 371         spin_unlock_bh(&m->tcf_lock);
 372         nlmsg_trim(skb, b);
 373         return -EMSGSIZE;
 374 }
 375
 376 static int tcf_mpls_walker(struct net *net, struct sk_buff *skb,
 377                            struct netlink_callback *cb, int type,
 378                            const struct tc_action_ops *ops,
 379                            struct netlink_ext_ack *extack)
 380 {
 381         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 382
 383         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 384 }
 385
 386 static int tcf_mpls_search(struct net *net, struct tc_action **a, u32 index)
 387 {
 388         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 389
 390         return tcf_idr_search(tn, a, index);
 391 }
 392
 393 static struct tc_action_ops act_mpls_ops = {
 394         .kind           =       "mpls",
 395         .id             =       TCA_ID_MPLS,
 396         .owner          =       THIS_MODULE,
 397         .act            =       tcf_mpls_act,
 398         .dump           =       tcf_mpls_dump,
 399         .init           =       tcf_mpls_init,
 400         .cleanup        =       tcf_mpls_cleanup,
 401         .walk           =       tcf_mpls_walker,
 402         .lookup         =       tcf_mpls_search,
 403         .size           =       sizeof(struct tcf_mpls),
 404 };
 405
 406 static __net_init int mpls_init_net(struct net *net)
 407 {
 408         struct tc_action_net *tn = net_generic(net, mpls_net_id);
 409
 410         return tc_action_net_init(net, tn, &act_mpls_ops);
 411 }
 412
 413 static void __net_exit mpls_exit_net(struct list_head *net_list)
 414 {
 415         tc_action_net_exit(net_list, mpls_net_id);
 416 }
 417
 418 static struct pernet_operations mpls_net_ops = {
 419         .init = mpls_init_net,
 420         .exit_batch = mpls_exit_net,
 421         .id   = &mpls_net_id,
 422         .size = sizeof(struct tc_action_net),
 423 };
 424
 425 static int __init mpls_init_module(void)
 426 {
 427         return tcf_register_action(&act_mpls_ops, &mpls_net_ops);
 428 }
 429
 430 static void __exit mpls_cleanup_module(void)
 431 {
 432         tcf_unregister_action(&act_mpls_ops, &mpls_net_ops);
 433 }
 434
 435 module_init(mpls_init_module);
 436 module_exit(mpls_cleanup_module);
 437
 438 MODULE_SOFTDEP("post: mpls_gso");
 439 MODULE_AUTHOR("Netronome Systems <oss-drivers@netronome.com>");
 440 MODULE_LICENSE("GPL");
 441 MODULE_DESCRIPTION("MPLS manipulation actions");