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