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