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