net/sched/act_ctinfo.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /* net/sched/act_ctinfo.c  netfilter ctinfo connmark actions
   3  *
   4  * Copyright (c) 2019 Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/kernel.h>
  10 #include <linux/skbuff.h>
  11 #include <linux/rtnetlink.h>
  12 #include <linux/pkt_cls.h>
  13 #include <linux/ip.h>
  14 #include <linux/ipv6.h>
  15 #include <net/netlink.h>
  16 #include <net/pkt_sched.h>
  17 #include <net/act_api.h>
  18 #include <net/pkt_cls.h>
  19 #include <uapi/linux/tc_act/tc_ctinfo.h>
  20 #include <net/tc_act/tc_ctinfo.h>
  21
  22 #include <net/netfilter/nf_conntrack.h>
  23 #include <net/netfilter/nf_conntrack_core.h>
  24 #include <net/netfilter/nf_conntrack_ecache.h>
  25 #include <net/netfilter/nf_conntrack_zones.h>
  26
  27 static struct tc_action_ops act_ctinfo_ops;
  28
  29 static void tcf_ctinfo_dscp_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
  30                                 struct tcf_ctinfo_params *cp,
  31                                 struct sk_buff *skb, int wlen, int proto)
  32 {
  33         u8 dscp, newdscp;
  34
  35         newdscp = (((ct->mark & cp->dscpmask) >> cp->dscpmaskshift) << 2) &
  36                      ~INET_ECN_MASK;
  37
  38         switch (proto) {
  39         case NFPROTO_IPV4:
  40                 dscp = ipv4_get_dsfield(ip_hdr(skb)) & ~INET_ECN_MASK;
  41                 if (dscp != newdscp) {
  42                         if (likely(!skb_try_make_writable(skb, wlen))) {
  43                                 ipv4_change_dsfield(ip_hdr(skb),
  44                                                     INET_ECN_MASK,
  45                                                     newdscp);
  46                                 ca->stats_dscp_set++;
  47                         } else {
  48                                 ca->stats_dscp_error++;
  49                         }
  50                 }
  51                 break;
  52         case NFPROTO_IPV6:
  53                 dscp = ipv6_get_dsfield(ipv6_hdr(skb)) & ~INET_ECN_MASK;
  54                 if (dscp != newdscp) {
  55                         if (likely(!skb_try_make_writable(skb, wlen))) {
  56                                 ipv6_change_dsfield(ipv6_hdr(skb),
  57                                                     INET_ECN_MASK,
  58                                                     newdscp);
  59                                 ca->stats_dscp_set++;
  60                         } else {
  61                                 ca->stats_dscp_error++;
  62                         }
  63                 }
  64                 break;
  65         default:
  66                 break;
  67         }
  68 }
  69
  70 static void tcf_ctinfo_cpmark_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
  71                                   struct tcf_ctinfo_params *cp,
  72                                   struct sk_buff *skb)
  73 {
  74         ca->stats_cpmark_set++;
  75         skb->mark = ct->mark & cp->cpmarkmask;
  76 }
  77
  78 static int tcf_ctinfo_act(struct sk_buff *skb, const struct tc_action *a,
  79                           struct tcf_result *res)
  80 {
  81         const struct nf_conntrack_tuple_hash *thash = NULL;
  82         struct tcf_ctinfo *ca = to_ctinfo(a);
  83         struct nf_conntrack_tuple tuple;
  84         struct nf_conntrack_zone zone;
  85         enum ip_conntrack_info ctinfo;
  86         struct tcf_ctinfo_params *cp;
  87         struct nf_conn *ct;
  88         int proto, wlen;
  89         int action;
  90
  91         cp = rcu_dereference_bh(ca->params);
  92
  93         tcf_lastuse_update(&ca->tcf_tm);
  94         bstats_update(&ca->tcf_bstats, skb);
  95         action = READ_ONCE(ca->tcf_action);
  96
  97         wlen = skb_network_offset(skb);
  98         switch (skb_protocol(skb, true)) {
  99         case htons(ETH_P_IP):
 100                 wlen += sizeof(struct iphdr);
 101                 if (!pskb_may_pull(skb, wlen))
 102                         goto out;
 103
 104                 proto = NFPROTO_IPV4;
 105                 break;
 106         case htons(ETH_P_IPV6):
 107                 wlen += sizeof(struct ipv6hdr);
 108                 if (!pskb_may_pull(skb, wlen))
 109                         goto out;
 110
 111                 proto = NFPROTO_IPV6;
 112                 break;
 113         default:
 114                 goto out;
 115         }
 116
 117         ct = nf_ct_get(skb, &ctinfo);
 118         if (!ct) { /* look harder, usually ingress */
 119                 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
 120                                        proto, cp->net, &tuple))
 121                         goto out;
 122                 zone.id = cp->zone;
 123                 zone.dir = NF_CT_DEFAULT_ZONE_DIR;
 124
 125                 thash = nf_conntrack_find_get(cp->net, &zone, &tuple);
 126                 if (!thash)
 127                         goto out;
 128
 129                 ct = nf_ct_tuplehash_to_ctrack(thash);
 130         }
 131
 132         if (cp->mode & CTINFO_MODE_DSCP)
 133                 if (!cp->dscpstatemask || (ct->mark & cp->dscpstatemask))
 134                         tcf_ctinfo_dscp_set(ct, ca, cp, skb, wlen, proto);
 135
 136         if (cp->mode & CTINFO_MODE_CPMARK)
 137                 tcf_ctinfo_cpmark_set(ct, ca, cp, skb);
 138
 139         if (thash)
 140                 nf_ct_put(ct);
 141 out:
 142         return action;
 143 }
 144
 145 static const struct nla_policy ctinfo_policy[TCA_CTINFO_MAX + 1] = {
 146         [TCA_CTINFO_ACT]                  =
 147                 NLA_POLICY_EXACT_LEN(sizeof(struct tc_ctinfo)),
 148         [TCA_CTINFO_ZONE]                 = { .type = NLA_U16 },
 149         [TCA_CTINFO_PARMS_DSCP_MASK]      = { .type = NLA_U32 },
 150         [TCA_CTINFO_PARMS_DSCP_STATEMASK] = { .type = NLA_U32 },
 151         [TCA_CTINFO_PARMS_CPMARK_MASK]    = { .type = NLA_U32 },
 152 };
 153
 154 static int tcf_ctinfo_init(struct net *net, struct nlattr *nla,
 155                            struct nlattr *est, struct tc_action **a,
 156                            struct tcf_proto *tp, u32 flags,
 157                            struct netlink_ext_ack *extack)
 158 {
 159         struct tc_action_net *tn = net_generic(net, act_ctinfo_ops.net_id);
 160         bool bind = flags & TCA_ACT_FLAGS_BIND;
 161         u32 dscpmask = 0, dscpstatemask, index;
 162         struct nlattr *tb[TCA_CTINFO_MAX + 1];
 163         struct tcf_ctinfo_params *cp_new;
 164         struct tcf_chain *goto_ch = NULL;
 165         struct tc_ctinfo *actparm;
 166         struct tcf_ctinfo *ci;
 167         u8 dscpmaskshift;
 168         int ret = 0, err;
 169
 170         if (!nla) {
 171                 NL_SET_ERR_MSG_MOD(extack, "ctinfo requires attributes to be passed");
 172                 return -EINVAL;
 173         }
 174
 175         err = nla_parse_nested(tb, TCA_CTINFO_MAX, nla, ctinfo_policy, extack);
 176         if (err < 0)
 177                 return err;
 178
 179         if (!tb[TCA_CTINFO_ACT]) {
 180                 NL_SET_ERR_MSG_MOD(extack,
 181                                    "Missing required TCA_CTINFO_ACT attribute");
 182                 return -EINVAL;
 183         }
 184         actparm = nla_data(tb[TCA_CTINFO_ACT]);
 185
 186         /* do some basic validation here before dynamically allocating things */
 187         /* that we would otherwise have to clean up.                          */
 188         if (tb[TCA_CTINFO_PARMS_DSCP_MASK]) {
 189                 dscpmask = nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_MASK]);
 190                 /* need contiguous 6 bit mask */
 191                 dscpmaskshift = dscpmask ? __ffs(dscpmask) : 0;
 192                 if ((~0 & (dscpmask >> dscpmaskshift)) != 0x3f) {
 193                         NL_SET_ERR_MSG_ATTR(extack,
 194                                             tb[TCA_CTINFO_PARMS_DSCP_MASK],
 195                                             "dscp mask must be 6 contiguous bits");
 196                         return -EINVAL;
 197                 }
 198                 dscpstatemask = tb[TCA_CTINFO_PARMS_DSCP_STATEMASK] ?
 199                         nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_STATEMASK]) : 0;
 200                 /* mask & statemask must not overlap */
 201                 if (dscpmask & dscpstatemask) {
 202                         NL_SET_ERR_MSG_ATTR(extack,
 203                                             tb[TCA_CTINFO_PARMS_DSCP_STATEMASK],
 204                                             "dscp statemask must not overlap dscp mask");
 205                         return -EINVAL;
 206                 }
 207         }
 208
 209         /* done the validation:now to the actual action allocation */
 210         index = actparm->index;
 211         err = tcf_idr_check_alloc(tn, &index, a, bind);
 212         if (!err) {
 213                 ret = tcf_idr_create(tn, index, est, a,
 214                                      &act_ctinfo_ops, bind, false, flags);
 215                 if (ret) {
 216                         tcf_idr_cleanup(tn, index);
 217                         return ret;
 218                 }
 219                 ret = ACT_P_CREATED;
 220         } else if (err > 0) {
 221                 if (bind) /* don't override defaults */
 222                         return 0;
 223                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 224                         tcf_idr_release(*a, bind);
 225                         return -EEXIST;
 226                 }
 227         } else {
 228                 return err;
 229         }
 230
 231         err = tcf_action_check_ctrlact(actparm->action, tp, &goto_ch, extack);
 232         if (err < 0)
 233                 goto release_idr;
 234
 235         ci = to_ctinfo(*a);
 236
 237         cp_new = kzalloc(sizeof(*cp_new), GFP_KERNEL);
 238         if (unlikely(!cp_new)) {
 239                 err = -ENOMEM;
 240                 goto put_chain;
 241         }
 242
 243         cp_new->net = net;
 244         cp_new->zone = tb[TCA_CTINFO_ZONE] ?
 245                         nla_get_u16(tb[TCA_CTINFO_ZONE]) : 0;
 246         if (dscpmask) {
 247                 cp_new->dscpmask = dscpmask;
 248                 cp_new->dscpmaskshift = dscpmaskshift;
 249                 cp_new->dscpstatemask = dscpstatemask;
 250                 cp_new->mode |= CTINFO_MODE_DSCP;
 251         }
 252
 253         if (tb[TCA_CTINFO_PARMS_CPMARK_MASK]) {
 254                 cp_new->cpmarkmask =
 255                                 nla_get_u32(tb[TCA_CTINFO_PARMS_CPMARK_MASK]);
 256                 cp_new->mode |= CTINFO_MODE_CPMARK;
 257         }
 258
 259         spin_lock_bh(&ci->tcf_lock);
 260         goto_ch = tcf_action_set_ctrlact(*a, actparm->action, goto_ch);
 261         cp_new = rcu_replace_pointer(ci->params, cp_new,
 262                                      lockdep_is_held(&ci->tcf_lock));
 263         spin_unlock_bh(&ci->tcf_lock);
 264
 265         if (goto_ch)
 266                 tcf_chain_put_by_act(goto_ch);
 267         if (cp_new)
 268                 kfree_rcu(cp_new, rcu);
 269
 270         return ret;
 271
 272 put_chain:
 273         if (goto_ch)
 274                 tcf_chain_put_by_act(goto_ch);
 275 release_idr:
 276         tcf_idr_release(*a, bind);
 277         return err;
 278 }
 279
 280 static int tcf_ctinfo_dump(struct sk_buff *skb, struct tc_action *a,
 281                            int bind, int ref)
 282 {
 283         struct tcf_ctinfo *ci = to_ctinfo(a);
 284         struct tc_ctinfo opt = {
 285                 .index   = ci->tcf_index,
 286                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 287                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 288         };
 289         unsigned char *b = skb_tail_pointer(skb);
 290         struct tcf_ctinfo_params *cp;
 291         struct tcf_t t;
 292
 293         spin_lock_bh(&ci->tcf_lock);
 294         cp = rcu_dereference_protected(ci->params,
 295                                        lockdep_is_held(&ci->tcf_lock));
 296
 297         tcf_tm_dump(&t, &ci->tcf_tm);
 298         if (nla_put_64bit(skb, TCA_CTINFO_TM, sizeof(t), &t, TCA_CTINFO_PAD))
 299                 goto nla_put_failure;
 300
 301         opt.action = ci->tcf_action;
 302         if (nla_put(skb, TCA_CTINFO_ACT, sizeof(opt), &opt))
 303                 goto nla_put_failure;
 304
 305         if (nla_put_u16(skb, TCA_CTINFO_ZONE, cp->zone))
 306                 goto nla_put_failure;
 307
 308         if (cp->mode & CTINFO_MODE_DSCP) {
 309                 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_MASK,
 310                                 cp->dscpmask))
 311                         goto nla_put_failure;
 312                 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_STATEMASK,
 313                                 cp->dscpstatemask))
 314                         goto nla_put_failure;
 315         }
 316
 317         if (cp->mode & CTINFO_MODE_CPMARK) {
 318                 if (nla_put_u32(skb, TCA_CTINFO_PARMS_CPMARK_MASK,
 319                                 cp->cpmarkmask))
 320                         goto nla_put_failure;
 321         }
 322
 323         if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_SET,
 324                               ci->stats_dscp_set, TCA_CTINFO_PAD))
 325                 goto nla_put_failure;
 326
 327         if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_ERROR,
 328                               ci->stats_dscp_error, TCA_CTINFO_PAD))
 329                 goto nla_put_failure;
 330
 331         if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_CPMARK_SET,
 332                               ci->stats_cpmark_set, TCA_CTINFO_PAD))
 333                 goto nla_put_failure;
 334
 335         spin_unlock_bh(&ci->tcf_lock);
 336         return skb->len;
 337
 338 nla_put_failure:
 339         spin_unlock_bh(&ci->tcf_lock);
 340         nlmsg_trim(skb, b);
 341         return -1;
 342 }
 343
 344 static void tcf_ctinfo_cleanup(struct tc_action *a)
 345 {
 346         struct tcf_ctinfo *ci = to_ctinfo(a);
 347         struct tcf_ctinfo_params *cp;
 348
 349         cp = rcu_dereference_protected(ci->params, 1);
 350         if (cp)
 351                 kfree_rcu(cp, rcu);
 352 }
 353
 354 static struct tc_action_ops act_ctinfo_ops = {
 355         .kind   = "ctinfo",
 356         .id     = TCA_ID_CTINFO,
 357         .owner  = THIS_MODULE,
 358         .act    = tcf_ctinfo_act,
 359         .dump   = tcf_ctinfo_dump,
 360         .init   = tcf_ctinfo_init,
 361         .cleanup= tcf_ctinfo_cleanup,
 362         .size   = sizeof(struct tcf_ctinfo),
 363 };
 364
 365 static __net_init int ctinfo_init_net(struct net *net)
 366 {
 367         struct tc_action_net *tn = net_generic(net, act_ctinfo_ops.net_id);
 368
 369         return tc_action_net_init(net, tn, &act_ctinfo_ops);
 370 }
 371
 372 static void __net_exit ctinfo_exit_net(struct list_head *net_list)
 373 {
 374         tc_action_net_exit(net_list, act_ctinfo_ops.net_id);
 375 }
 376
 377 static struct pernet_operations ctinfo_net_ops = {
 378         .init           = ctinfo_init_net,
 379         .exit_batch     = ctinfo_exit_net,
 380         .id             = &act_ctinfo_ops.net_id,
 381         .size           = sizeof(struct tc_action_net),
 382 };
 383
 384 static int __init ctinfo_init_module(void)
 385 {
 386         return tcf_register_action(&act_ctinfo_ops, &ctinfo_net_ops);
 387 }
 388
 389 static void __exit ctinfo_cleanup_module(void)
 390 {
 391         tcf_unregister_action(&act_ctinfo_ops, &ctinfo_net_ops);
 392 }
 393
 394 module_init(ctinfo_init_module);
 395 module_exit(ctinfo_cleanup_module);
 396 MODULE_AUTHOR("Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>");
 397 MODULE_DESCRIPTION("Connection tracking mark actions");
 398 MODULE_LICENSE("GPL");