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 static unsigned int ctinfo_net_id;
  29
  30 static void tcf_ctinfo_dscp_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
  31                                 struct tcf_ctinfo_params *cp,
  32                                 struct sk_buff *skb, int wlen, int proto)
  33 {
  34         u8 dscp, newdscp;
  35
  36         newdscp = (((ct->mark & cp->dscpmask) >> cp->dscpmaskshift) << 2) &
  37                      ~INET_ECN_MASK;
  38
  39         switch (proto) {
  40         case NFPROTO_IPV4:
  41                 dscp = ipv4_get_dsfield(ip_hdr(skb)) & ~INET_ECN_MASK;
  42                 if (dscp != newdscp) {
  43                         if (likely(!skb_try_make_writable(skb, wlen))) {
  44                                 ipv4_change_dsfield(ip_hdr(skb),
  45                                                     INET_ECN_MASK,
  46                                                     newdscp);
  47                                 ca->stats_dscp_set++;
  48                         } else {
  49                                 ca->stats_dscp_error++;
  50                         }
  51                 }
  52                 break;
  53         case NFPROTO_IPV6:
  54                 dscp = ipv6_get_dsfield(ipv6_hdr(skb)) & ~INET_ECN_MASK;
  55                 if (dscp != newdscp) {
  56                         if (likely(!skb_try_make_writable(skb, wlen))) {
  57                                 ipv6_change_dsfield(ipv6_hdr(skb),
  58                                                     INET_ECN_MASK,
  59                                                     newdscp);
  60                                 ca->stats_dscp_set++;
  61                         } else {
  62                                 ca->stats_dscp_error++;
  63                         }
  64                 }
  65                 break;
  66         default:
  67                 break;
  68         }
  69 }
  70
  71 static void tcf_ctinfo_cpmark_set(struct nf_conn *ct, struct tcf_ctinfo *ca,
  72                                   struct tcf_ctinfo_params *cp,
  73                                   struct sk_buff *skb)
  74 {
  75         ca->stats_cpmark_set++;
  76         skb->mark = ct->mark & cp->cpmarkmask;
  77 }
  78
  79 static int tcf_ctinfo_act(struct sk_buff *skb, const struct tc_action *a,
  80                           struct tcf_result *res)
  81 {
  82         const struct nf_conntrack_tuple_hash *thash = NULL;
  83         struct tcf_ctinfo *ca = to_ctinfo(a);
  84         struct nf_conntrack_tuple tuple;
  85         struct nf_conntrack_zone zone;
  86         enum ip_conntrack_info ctinfo;
  87         struct tcf_ctinfo_params *cp;
  88         struct nf_conn *ct;
  89         int proto, wlen;
  90         int action;
  91
  92         cp = rcu_dereference_bh(ca->params);
  93
  94         tcf_lastuse_update(&ca->tcf_tm);
  95         bstats_update(&ca->tcf_bstats, skb);
  96         action = READ_ONCE(ca->tcf_action);
  97
  98         wlen = skb_network_offset(skb);
  99         switch (skb_protocol(skb, true)) {
 100         case htons(ETH_P_IP):
 101                 wlen += sizeof(struct iphdr);
 102                 if (!pskb_may_pull(skb, wlen))
 103                         goto out;
 104
 105                 proto = NFPROTO_IPV4;
 106                 break;
 107         case htons(ETH_P_IPV6):
 108                 wlen += sizeof(struct ipv6hdr);
 109                 if (!pskb_may_pull(skb, wlen))
 110                         goto out;
 111
 112                 proto = NFPROTO_IPV6;
 113                 break;
 114         default:
 115                 goto out;
 116         }
 117
 118         ct = nf_ct_get(skb, &ctinfo);
 119         if (!ct) { /* look harder, usually ingress */
 120                 if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb),
 121                                        proto, cp->net, &tuple))
 122                         goto out;
 123                 zone.id = cp->zone;
 124                 zone.dir = NF_CT_DEFAULT_ZONE_DIR;
 125
 126                 thash = nf_conntrack_find_get(cp->net, &zone, &tuple);
 127                 if (!thash)
 128                         goto out;
 129
 130                 ct = nf_ct_tuplehash_to_ctrack(thash);
 131         }
 132
 133         if (cp->mode & CTINFO_MODE_DSCP)
 134                 if (!cp->dscpstatemask || (ct->mark & cp->dscpstatemask))
 135                         tcf_ctinfo_dscp_set(ct, ca, cp, skb, wlen, proto);
 136
 137         if (cp->mode & CTINFO_MODE_CPMARK)
 138                 tcf_ctinfo_cpmark_set(ct, ca, cp, skb);
 139
 140         if (thash)
 141                 nf_ct_put(ct);
 142 out:
 143         return action;
 144 }
 145
 146 static const struct nla_policy ctinfo_policy[TCA_CTINFO_MAX + 1] = {
 147         [TCA_CTINFO_ACT]                  =
 148                 NLA_POLICY_EXACT_LEN(sizeof(struct tc_ctinfo)),
 149         [TCA_CTINFO_ZONE]                 = { .type = NLA_U16 },
 150         [TCA_CTINFO_PARMS_DSCP_MASK]      = { .type = NLA_U32 },
 151         [TCA_CTINFO_PARMS_DSCP_STATEMASK] = { .type = NLA_U32 },
 152         [TCA_CTINFO_PARMS_CPMARK_MASK]    = { .type = NLA_U32 },
 153 };
 154
 155 static int tcf_ctinfo_init(struct net *net, struct nlattr *nla,
 156                            struct nlattr *est, struct tc_action **a,
 157                            struct tcf_proto *tp, u32 flags,
 158                            struct netlink_ext_ack *extack)
 159 {
 160         struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
 161         bool bind = flags & TCA_ACT_FLAGS_BIND;
 162         u32 dscpmask = 0, dscpstatemask, index;
 163         struct nlattr *tb[TCA_CTINFO_MAX + 1];
 164         struct tcf_ctinfo_params *cp_new;
 165         struct tcf_chain *goto_ch = NULL;
 166         struct tc_ctinfo *actparm;
 167         struct tcf_ctinfo *ci;
 168         u8 dscpmaskshift;
 169         int ret = 0, err;
 170
 171         if (!nla) {
 172                 NL_SET_ERR_MSG_MOD(extack, "ctinfo requires attributes to be passed");
 173                 return -EINVAL;
 174         }
 175
 176         err = nla_parse_nested(tb, TCA_CTINFO_MAX, nla, ctinfo_policy, extack);
 177         if (err < 0)
 178                 return err;
 179
 180         if (!tb[TCA_CTINFO_ACT]) {
 181                 NL_SET_ERR_MSG_MOD(extack,
 182                                    "Missing required TCA_CTINFO_ACT attribute");
 183                 return -EINVAL;
 184         }
 185         actparm = nla_data(tb[TCA_CTINFO_ACT]);
 186
 187         /* do some basic validation here before dynamically allocating things */
 188         /* that we would otherwise have to clean up.                          */
 189         if (tb[TCA_CTINFO_PARMS_DSCP_MASK]) {
 190                 dscpmask = nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_MASK]);
 191                 /* need contiguous 6 bit mask */
 192                 dscpmaskshift = dscpmask ? __ffs(dscpmask) : 0;
 193                 if ((~0 & (dscpmask >> dscpmaskshift)) != 0x3f) {
 194                         NL_SET_ERR_MSG_ATTR(extack,
 195                                             tb[TCA_CTINFO_PARMS_DSCP_MASK],
 196                                             "dscp mask must be 6 contiguous bits");
 197                         return -EINVAL;
 198                 }
 199                 dscpstatemask = tb[TCA_CTINFO_PARMS_DSCP_STATEMASK] ?
 200                         nla_get_u32(tb[TCA_CTINFO_PARMS_DSCP_STATEMASK]) : 0;
 201                 /* mask & statemask must not overlap */
 202                 if (dscpmask & dscpstatemask) {
 203                         NL_SET_ERR_MSG_ATTR(extack,
 204                                             tb[TCA_CTINFO_PARMS_DSCP_STATEMASK],
 205                                             "dscp statemask must not overlap dscp mask");
 206                         return -EINVAL;
 207                 }
 208         }
 209
 210         /* done the validation:now to the actual action allocation */
 211         index = actparm->index;
 212         err = tcf_idr_check_alloc(tn, &index, a, bind);
 213         if (!err) {
 214                 ret = tcf_idr_create(tn, index, est, a,
 215                                      &act_ctinfo_ops, bind, false, 0);
 216                 if (ret) {
 217                         tcf_idr_cleanup(tn, index);
 218                         return ret;
 219                 }
 220                 ret = ACT_P_CREATED;
 221         } else if (err > 0) {
 222                 if (bind) /* don't override defaults */
 223                         return 0;
 224                 if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
 225                         tcf_idr_release(*a, bind);
 226                         return -EEXIST;
 227                 }
 228         } else {
 229                 return err;
 230         }
 231
 232         err = tcf_action_check_ctrlact(actparm->action, tp, &goto_ch, extack);
 233         if (err < 0)
 234                 goto release_idr;
 235
 236         ci = to_ctinfo(*a);
 237
 238         cp_new = kzalloc(sizeof(*cp_new), GFP_KERNEL);
 239         if (unlikely(!cp_new)) {
 240                 err = -ENOMEM;
 241                 goto put_chain;
 242         }
 243
 244         cp_new->net = net;
 245         cp_new->zone = tb[TCA_CTINFO_ZONE] ?
 246                         nla_get_u16(tb[TCA_CTINFO_ZONE]) : 0;
 247         if (dscpmask) {
 248                 cp_new->dscpmask = dscpmask;
 249                 cp_new->dscpmaskshift = dscpmaskshift;
 250                 cp_new->dscpstatemask = dscpstatemask;
 251                 cp_new->mode |= CTINFO_MODE_DSCP;
 252         }
 253
 254         if (tb[TCA_CTINFO_PARMS_CPMARK_MASK]) {
 255                 cp_new->cpmarkmask =
 256                                 nla_get_u32(tb[TCA_CTINFO_PARMS_CPMARK_MASK]);
 257                 cp_new->mode |= CTINFO_MODE_CPMARK;
 258         }
 259
 260         spin_lock_bh(&ci->tcf_lock);
 261         goto_ch = tcf_action_set_ctrlact(*a, actparm->action, goto_ch);
 262         cp_new = rcu_replace_pointer(ci->params, cp_new,
 263                                      lockdep_is_held(&ci->tcf_lock));
 264         spin_unlock_bh(&ci->tcf_lock);
 265
 266         if (goto_ch)
 267                 tcf_chain_put_by_act(goto_ch);
 268         if (cp_new)
 269                 kfree_rcu(cp_new, rcu);
 270
 271         return ret;
 272
 273 put_chain:
 274         if (goto_ch)
 275                 tcf_chain_put_by_act(goto_ch);
 276 release_idr:
 277         tcf_idr_release(*a, bind);
 278         return err;
 279 }
 280
 281 static int tcf_ctinfo_dump(struct sk_buff *skb, struct tc_action *a,
 282                            int bind, int ref)
 283 {
 284         struct tcf_ctinfo *ci = to_ctinfo(a);
 285         struct tc_ctinfo opt = {
 286                 .index   = ci->tcf_index,
 287                 .refcnt  = refcount_read(&ci->tcf_refcnt) - ref,
 288                 .bindcnt = atomic_read(&ci->tcf_bindcnt) - bind,
 289         };
 290         unsigned char *b = skb_tail_pointer(skb);
 291         struct tcf_ctinfo_params *cp;
 292         struct tcf_t t;
 293
 294         spin_lock_bh(&ci->tcf_lock);
 295         cp = rcu_dereference_protected(ci->params,
 296                                        lockdep_is_held(&ci->tcf_lock));
 297
 298         tcf_tm_dump(&t, &ci->tcf_tm);
 299         if (nla_put_64bit(skb, TCA_CTINFO_TM, sizeof(t), &t, TCA_CTINFO_PAD))
 300                 goto nla_put_failure;
 301
 302         opt.action = ci->tcf_action;
 303         if (nla_put(skb, TCA_CTINFO_ACT, sizeof(opt), &opt))
 304                 goto nla_put_failure;
 305
 306         if (nla_put_u16(skb, TCA_CTINFO_ZONE, cp->zone))
 307                 goto nla_put_failure;
 308
 309         if (cp->mode & CTINFO_MODE_DSCP) {
 310                 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_MASK,
 311                                 cp->dscpmask))
 312                         goto nla_put_failure;
 313                 if (nla_put_u32(skb, TCA_CTINFO_PARMS_DSCP_STATEMASK,
 314                                 cp->dscpstatemask))
 315                         goto nla_put_failure;
 316         }
 317
 318         if (cp->mode & CTINFO_MODE_CPMARK) {
 319                 if (nla_put_u32(skb, TCA_CTINFO_PARMS_CPMARK_MASK,
 320                                 cp->cpmarkmask))
 321                         goto nla_put_failure;
 322         }
 323
 324         if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_SET,
 325                               ci->stats_dscp_set, TCA_CTINFO_PAD))
 326                 goto nla_put_failure;
 327
 328         if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_DSCP_ERROR,
 329                               ci->stats_dscp_error, TCA_CTINFO_PAD))
 330                 goto nla_put_failure;
 331
 332         if (nla_put_u64_64bit(skb, TCA_CTINFO_STATS_CPMARK_SET,
 333                               ci->stats_cpmark_set, TCA_CTINFO_PAD))
 334                 goto nla_put_failure;
 335
 336         spin_unlock_bh(&ci->tcf_lock);
 337         return skb->len;
 338
 339 nla_put_failure:
 340         spin_unlock_bh(&ci->tcf_lock);
 341         nlmsg_trim(skb, b);
 342         return -1;
 343 }
 344
 345 static int tcf_ctinfo_walker(struct net *net, struct sk_buff *skb,
 346                              struct netlink_callback *cb, int type,
 347                              const struct tc_action_ops *ops,
 348                              struct netlink_ext_ack *extack)
 349 {
 350         struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
 351
 352         return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 353 }
 354
 355 static int tcf_ctinfo_search(struct net *net, struct tc_action **a, u32 index)
 356 {
 357         struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
 358
 359         return tcf_idr_search(tn, a, index);
 360 }
 361
 362 static void tcf_ctinfo_cleanup(struct tc_action *a)
 363 {
 364         struct tcf_ctinfo *ci = to_ctinfo(a);
 365         struct tcf_ctinfo_params *cp;
 366
 367         cp = rcu_dereference_protected(ci->params, 1);
 368         if (cp)
 369                 kfree_rcu(cp, rcu);
 370 }
 371
 372 static struct tc_action_ops act_ctinfo_ops = {
 373         .kind   = "ctinfo",
 374         .id     = TCA_ID_CTINFO,
 375         .owner  = THIS_MODULE,
 376         .act    = tcf_ctinfo_act,
 377         .dump   = tcf_ctinfo_dump,
 378         .init   = tcf_ctinfo_init,
 379         .cleanup= tcf_ctinfo_cleanup,
 380         .walk   = tcf_ctinfo_walker,
 381         .lookup = tcf_ctinfo_search,
 382         .size   = sizeof(struct tcf_ctinfo),
 383 };
 384
 385 static __net_init int ctinfo_init_net(struct net *net)
 386 {
 387         struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
 388
 389         return tc_action_net_init(net, tn, &act_ctinfo_ops);
 390 }
 391
 392 static void __net_exit ctinfo_exit_net(struct list_head *net_list)
 393 {
 394         tc_action_net_exit(net_list, ctinfo_net_id);
 395 }
 396
 397 static struct pernet_operations ctinfo_net_ops = {
 398         .init           = ctinfo_init_net,
 399         .exit_batch     = ctinfo_exit_net,
 400         .id             = &ctinfo_net_id,
 401         .size           = sizeof(struct tc_action_net),
 402 };
 403
 404 static int __init ctinfo_init_module(void)
 405 {
 406         return tcf_register_action(&act_ctinfo_ops, &ctinfo_net_ops);
 407 }
 408
 409 static void __exit ctinfo_cleanup_module(void)
 410 {
 411         tcf_unregister_action(&act_ctinfo_ops, &ctinfo_net_ops);
 412 }
 413
 414 module_init(ctinfo_init_module);
 415 module_exit(ctinfo_cleanup_module);
 416 MODULE_AUTHOR("Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>");
 417 MODULE_DESCRIPTION("Connection tracking mark actions");
 418 MODULE_LICENSE("GPL");