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