linux/net/sched/act_ctinfo.c
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   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
  27static struct tc_action_ops act_ctinfo_ops;
  28static unsigned int ctinfo_net_id;
  29
  30static 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
  71static 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
  79static 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);
 142out:
 143        return action;
 144}
 145
 146static 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
 155static int tcf_ctinfo_init(struct net *net, struct nlattr *nla,
 156                           struct nlattr *est, struct tc_action **a,
 157                           int ovr, int bind, bool rtnl_held,
 158                           struct tcf_proto *tp, u32 flags,
 159                           struct netlink_ext_ack *extack)
 160{
 161        struct tc_action_net *tn = net_generic(net, ctinfo_net_id);
 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 (!ovr) {
 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
 273put_chain:
 274        if (goto_ch)
 275                tcf_chain_put_by_act(goto_ch);
 276release_idr:
 277        tcf_idr_release(*a, bind);
 278        return err;
 279}
 280
 281static 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
 339nla_put_failure:
 340        spin_unlock_bh(&ci->tcf_lock);
 341        nlmsg_trim(skb, b);
 342        return -1;
 343}
 344
 345static 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
 355static 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
 362static 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
 372static 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
 385static __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
 392static void __net_exit ctinfo_exit_net(struct list_head *net_list)
 393{
 394        tc_action_net_exit(net_list, ctinfo_net_id);
 395}
 396
 397static 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
 404static int __init ctinfo_init_module(void)
 405{
 406        return tcf_register_action(&act_ctinfo_ops, &ctinfo_net_ops);
 407}
 408
 409static void __exit ctinfo_cleanup_module(void)
 410{
 411        tcf_unregister_action(&act_ctinfo_ops, &ctinfo_net_ops);
 412}
 413
 414module_init(ctinfo_init_module);
 415module_exit(ctinfo_cleanup_module);
 416MODULE_AUTHOR("Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>");
 417MODULE_DESCRIPTION("Connection tracking mark actions");
 418MODULE_LICENSE("GPL");
 419
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