linux/net/sched/act_pedit.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * net/sched/act_pedit.c        Generic packet editor
   4 *
   5 * Authors:     Jamal Hadi Salim (2002-4)
   6 */
   7
   8#include <linux/types.h>
   9#include <linux/kernel.h>
  10#include <linux/string.h>
  11#include <linux/errno.h>
  12#include <linux/skbuff.h>
  13#include <linux/rtnetlink.h>
  14#include <linux/module.h>
  15#include <linux/init.h>
  16#include <linux/slab.h>
  17#include <net/netlink.h>
  18#include <net/pkt_sched.h>
  19#include <linux/tc_act/tc_pedit.h>
  20#include <net/tc_act/tc_pedit.h>
  21#include <uapi/linux/tc_act/tc_pedit.h>
  22#include <net/pkt_cls.h>
  23
  24static unsigned int pedit_net_id;
  25static struct tc_action_ops act_pedit_ops;
  26
  27static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
  28        [TCA_PEDIT_PARMS]       = { .len = sizeof(struct tc_pedit) },
  29        [TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
  30};
  31
  32static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
  33        [TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
  34        [TCA_PEDIT_KEY_EX_CMD]    = { .type = NLA_U16 },
  35};
  36
  37static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
  38                                                        u8 n)
  39{
  40        struct tcf_pedit_key_ex *keys_ex;
  41        struct tcf_pedit_key_ex *k;
  42        const struct nlattr *ka;
  43        int err = -EINVAL;
  44        int rem;
  45
  46        if (!nla)
  47                return NULL;
  48
  49        keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
  50        if (!keys_ex)
  51                return ERR_PTR(-ENOMEM);
  52
  53        k = keys_ex;
  54
  55        nla_for_each_nested(ka, nla, rem) {
  56                struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
  57
  58                if (!n) {
  59                        err = -EINVAL;
  60                        goto err_out;
  61                }
  62                n--;
  63
  64                if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
  65                        err = -EINVAL;
  66                        goto err_out;
  67                }
  68
  69                err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
  70                                                  ka, pedit_key_ex_policy,
  71                                                  NULL);
  72                if (err)
  73                        goto err_out;
  74
  75                if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
  76                    !tb[TCA_PEDIT_KEY_EX_CMD]) {
  77                        err = -EINVAL;
  78                        goto err_out;
  79                }
  80
  81                k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
  82                k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
  83
  84                if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
  85                    k->cmd > TCA_PEDIT_CMD_MAX) {
  86                        err = -EINVAL;
  87                        goto err_out;
  88                }
  89
  90                k++;
  91        }
  92
  93        if (n) {
  94                err = -EINVAL;
  95                goto err_out;
  96        }
  97
  98        return keys_ex;
  99
 100err_out:
 101        kfree(keys_ex);
 102        return ERR_PTR(err);
 103}
 104
 105static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
 106                                 struct tcf_pedit_key_ex *keys_ex, int n)
 107{
 108        struct nlattr *keys_start = nla_nest_start_noflag(skb,
 109                                                          TCA_PEDIT_KEYS_EX);
 110
 111        if (!keys_start)
 112                goto nla_failure;
 113        for (; n > 0; n--) {
 114                struct nlattr *key_start;
 115
 116                key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
 117                if (!key_start)
 118                        goto nla_failure;
 119
 120                if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
 121                    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
 122                        goto nla_failure;
 123
 124                nla_nest_end(skb, key_start);
 125
 126                keys_ex++;
 127        }
 128
 129        nla_nest_end(skb, keys_start);
 130
 131        return 0;
 132nla_failure:
 133        nla_nest_cancel(skb, keys_start);
 134        return -EINVAL;
 135}
 136
 137static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 138                          struct nlattr *est, struct tc_action **a,
 139                          int ovr, int bind, bool rtnl_held,
 140                          struct tcf_proto *tp, u32 flags,
 141                          struct netlink_ext_ack *extack)
 142{
 143        struct tc_action_net *tn = net_generic(net, pedit_net_id);
 144        struct nlattr *tb[TCA_PEDIT_MAX + 1];
 145        struct tcf_chain *goto_ch = NULL;
 146        struct tc_pedit_key *keys = NULL;
 147        struct tcf_pedit_key_ex *keys_ex;
 148        struct tc_pedit *parm;
 149        struct nlattr *pattr;
 150        struct tcf_pedit *p;
 151        int ret = 0, err;
 152        int ksize;
 153        u32 index;
 154
 155        if (!nla) {
 156                NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
 157                return -EINVAL;
 158        }
 159
 160        err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
 161                                          pedit_policy, NULL);
 162        if (err < 0)
 163                return err;
 164
 165        pattr = tb[TCA_PEDIT_PARMS];
 166        if (!pattr)
 167                pattr = tb[TCA_PEDIT_PARMS_EX];
 168        if (!pattr) {
 169                NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
 170                return -EINVAL;
 171        }
 172
 173        parm = nla_data(pattr);
 174        if (!parm->nkeys) {
 175                NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
 176                return -EINVAL;
 177        }
 178        ksize = parm->nkeys * sizeof(struct tc_pedit_key);
 179        if (nla_len(pattr) < sizeof(*parm) + ksize) {
 180                NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
 181                return -EINVAL;
 182        }
 183
 184        keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
 185        if (IS_ERR(keys_ex))
 186                return PTR_ERR(keys_ex);
 187
 188        index = parm->index;
 189        err = tcf_idr_check_alloc(tn, &index, a, bind);
 190        if (!err) {
 191                ret = tcf_idr_create(tn, index, est, a,
 192                                     &act_pedit_ops, bind, false, 0);
 193                if (ret) {
 194                        tcf_idr_cleanup(tn, index);
 195                        goto out_free;
 196                }
 197                ret = ACT_P_CREATED;
 198        } else if (err > 0) {
 199                if (bind)
 200                        goto out_free;
 201                if (!ovr) {
 202                        ret = -EEXIST;
 203                        goto out_release;
 204                }
 205        } else {
 206                ret = err;
 207                goto out_free;
 208        }
 209
 210        err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
 211        if (err < 0) {
 212                ret = err;
 213                goto out_release;
 214        }
 215        p = to_pedit(*a);
 216        spin_lock_bh(&p->tcf_lock);
 217
 218        if (ret == ACT_P_CREATED ||
 219            (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
 220                keys = kmalloc(ksize, GFP_ATOMIC);
 221                if (!keys) {
 222                        spin_unlock_bh(&p->tcf_lock);
 223                        ret = -ENOMEM;
 224                        goto put_chain;
 225                }
 226                kfree(p->tcfp_keys);
 227                p->tcfp_keys = keys;
 228                p->tcfp_nkeys = parm->nkeys;
 229        }
 230        memcpy(p->tcfp_keys, parm->keys, ksize);
 231
 232        p->tcfp_flags = parm->flags;
 233        goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
 234
 235        kfree(p->tcfp_keys_ex);
 236        p->tcfp_keys_ex = keys_ex;
 237
 238        spin_unlock_bh(&p->tcf_lock);
 239        if (goto_ch)
 240                tcf_chain_put_by_act(goto_ch);
 241        return ret;
 242
 243put_chain:
 244        if (goto_ch)
 245                tcf_chain_put_by_act(goto_ch);
 246out_release:
 247        tcf_idr_release(*a, bind);
 248out_free:
 249        kfree(keys_ex);
 250        return ret;
 251
 252}
 253
 254static void tcf_pedit_cleanup(struct tc_action *a)
 255{
 256        struct tcf_pedit *p = to_pedit(a);
 257        struct tc_pedit_key *keys = p->tcfp_keys;
 258
 259        kfree(keys);
 260        kfree(p->tcfp_keys_ex);
 261}
 262
 263static bool offset_valid(struct sk_buff *skb, int offset)
 264{
 265        if (offset > 0 && offset > skb->len)
 266                return false;
 267
 268        if  (offset < 0 && -offset > skb_headroom(skb))
 269                return false;
 270
 271        return true;
 272}
 273
 274static int pedit_skb_hdr_offset(struct sk_buff *skb,
 275                                enum pedit_header_type htype, int *hoffset)
 276{
 277        int ret = -EINVAL;
 278
 279        switch (htype) {
 280        case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
 281                if (skb_mac_header_was_set(skb)) {
 282                        *hoffset = skb_mac_offset(skb);
 283                        ret = 0;
 284                }
 285                break;
 286        case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
 287        case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
 288        case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
 289                *hoffset = skb_network_offset(skb);
 290                ret = 0;
 291                break;
 292        case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
 293        case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
 294                if (skb_transport_header_was_set(skb)) {
 295                        *hoffset = skb_transport_offset(skb);
 296                        ret = 0;
 297                }
 298                break;
 299        default:
 300                ret = -EINVAL;
 301                break;
 302        }
 303
 304        return ret;
 305}
 306
 307static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
 308                         struct tcf_result *res)
 309{
 310        struct tcf_pedit *p = to_pedit(a);
 311        int i;
 312
 313        if (skb_unclone(skb, GFP_ATOMIC))
 314                return p->tcf_action;
 315
 316        spin_lock(&p->tcf_lock);
 317
 318        tcf_lastuse_update(&p->tcf_tm);
 319
 320        if (p->tcfp_nkeys > 0) {
 321                struct tc_pedit_key *tkey = p->tcfp_keys;
 322                struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
 323                enum pedit_header_type htype =
 324                        TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
 325                enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
 326
 327                for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
 328                        u32 *ptr, hdata;
 329                        int offset = tkey->off;
 330                        int hoffset;
 331                        u32 val;
 332                        int rc;
 333
 334                        if (tkey_ex) {
 335                                htype = tkey_ex->htype;
 336                                cmd = tkey_ex->cmd;
 337
 338                                tkey_ex++;
 339                        }
 340
 341                        rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
 342                        if (rc) {
 343                                pr_info("tc action pedit bad header type specified (0x%x)\n",
 344                                        htype);
 345                                goto bad;
 346                        }
 347
 348                        if (tkey->offmask) {
 349                                u8 *d, _d;
 350
 351                                if (!offset_valid(skb, hoffset + tkey->at)) {
 352                                        pr_info("tc action pedit 'at' offset %d out of bounds\n",
 353                                                hoffset + tkey->at);
 354                                        goto bad;
 355                                }
 356                                d = skb_header_pointer(skb, hoffset + tkey->at,
 357                                                       sizeof(_d), &_d);
 358                                if (!d)
 359                                        goto bad;
 360                                offset += (*d & tkey->offmask) >> tkey->shift;
 361                        }
 362
 363                        if (offset % 4) {
 364                                pr_info("tc action pedit offset must be on 32 bit boundaries\n");
 365                                goto bad;
 366                        }
 367
 368                        if (!offset_valid(skb, hoffset + offset)) {
 369                                pr_info("tc action pedit offset %d out of bounds\n",
 370                                        hoffset + offset);
 371                                goto bad;
 372                        }
 373
 374                        ptr = skb_header_pointer(skb, hoffset + offset,
 375                                                 sizeof(hdata), &hdata);
 376                        if (!ptr)
 377                                goto bad;
 378                        /* just do it, baby */
 379                        switch (cmd) {
 380                        case TCA_PEDIT_KEY_EX_CMD_SET:
 381                                val = tkey->val;
 382                                break;
 383                        case TCA_PEDIT_KEY_EX_CMD_ADD:
 384                                val = (*ptr + tkey->val) & ~tkey->mask;
 385                                break;
 386                        default:
 387                                pr_info("tc action pedit bad command (%d)\n",
 388                                        cmd);
 389                                goto bad;
 390                        }
 391
 392                        *ptr = ((*ptr & tkey->mask) ^ val);
 393                        if (ptr == &hdata)
 394                                skb_store_bits(skb, hoffset + offset, ptr, 4);
 395                }
 396
 397                goto done;
 398        } else {
 399                WARN(1, "pedit BUG: index %d\n", p->tcf_index);
 400        }
 401
 402bad:
 403        p->tcf_qstats.overlimits++;
 404done:
 405        bstats_update(&p->tcf_bstats, skb);
 406        spin_unlock(&p->tcf_lock);
 407        return p->tcf_action;
 408}
 409
 410static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
 411                                   u64 drops, u64 lastuse, bool hw)
 412{
 413        struct tcf_pedit *d = to_pedit(a);
 414        struct tcf_t *tm = &d->tcf_tm;
 415
 416        tcf_action_update_stats(a, bytes, packets, drops, hw);
 417        tm->lastuse = max_t(u64, tm->lastuse, lastuse);
 418}
 419
 420static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 421                          int bind, int ref)
 422{
 423        unsigned char *b = skb_tail_pointer(skb);
 424        struct tcf_pedit *p = to_pedit(a);
 425        struct tc_pedit *opt;
 426        struct tcf_t t;
 427        int s;
 428
 429        s = struct_size(opt, keys, p->tcfp_nkeys);
 430
 431        /* netlink spinlocks held above us - must use ATOMIC */
 432        opt = kzalloc(s, GFP_ATOMIC);
 433        if (unlikely(!opt))
 434                return -ENOBUFS;
 435
 436        spin_lock_bh(&p->tcf_lock);
 437        memcpy(opt->keys, p->tcfp_keys, flex_array_size(opt, keys, p->tcfp_nkeys));
 438        opt->index = p->tcf_index;
 439        opt->nkeys = p->tcfp_nkeys;
 440        opt->flags = p->tcfp_flags;
 441        opt->action = p->tcf_action;
 442        opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
 443        opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
 444
 445        if (p->tcfp_keys_ex) {
 446                if (tcf_pedit_key_ex_dump(skb,
 447                                          p->tcfp_keys_ex,
 448                                          p->tcfp_nkeys))
 449                        goto nla_put_failure;
 450
 451                if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
 452                        goto nla_put_failure;
 453        } else {
 454                if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
 455                        goto nla_put_failure;
 456        }
 457
 458        tcf_tm_dump(&t, &p->tcf_tm);
 459        if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 460                goto nla_put_failure;
 461        spin_unlock_bh(&p->tcf_lock);
 462
 463        kfree(opt);
 464        return skb->len;
 465
 466nla_put_failure:
 467        spin_unlock_bh(&p->tcf_lock);
 468        nlmsg_trim(skb, b);
 469        kfree(opt);
 470        return -1;
 471}
 472
 473static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
 474                            struct netlink_callback *cb, int type,
 475                            const struct tc_action_ops *ops,
 476                            struct netlink_ext_ack *extack)
 477{
 478        struct tc_action_net *tn = net_generic(net, pedit_net_id);
 479
 480        return tcf_generic_walker(tn, skb, cb, type, ops, extack);
 481}
 482
 483static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
 484{
 485        struct tc_action_net *tn = net_generic(net, pedit_net_id);
 486
 487        return tcf_idr_search(tn, a, index);
 488}
 489
 490static struct tc_action_ops act_pedit_ops = {
 491        .kind           =       "pedit",
 492        .id             =       TCA_ID_PEDIT,
 493        .owner          =       THIS_MODULE,
 494        .act            =       tcf_pedit_act,
 495        .stats_update   =       tcf_pedit_stats_update,
 496        .dump           =       tcf_pedit_dump,
 497        .cleanup        =       tcf_pedit_cleanup,
 498        .init           =       tcf_pedit_init,
 499        .walk           =       tcf_pedit_walker,
 500        .lookup         =       tcf_pedit_search,
 501        .size           =       sizeof(struct tcf_pedit),
 502};
 503
 504static __net_init int pedit_init_net(struct net *net)
 505{
 506        struct tc_action_net *tn = net_generic(net, pedit_net_id);
 507
 508        return tc_action_net_init(net, tn, &act_pedit_ops);
 509}
 510
 511static void __net_exit pedit_exit_net(struct list_head *net_list)
 512{
 513        tc_action_net_exit(net_list, pedit_net_id);
 514}
 515
 516static struct pernet_operations pedit_net_ops = {
 517        .init = pedit_init_net,
 518        .exit_batch = pedit_exit_net,
 519        .id   = &pedit_net_id,
 520        .size = sizeof(struct tc_action_net),
 521};
 522
 523MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
 524MODULE_DESCRIPTION("Generic Packet Editor actions");
 525MODULE_LICENSE("GPL");
 526
 527static int __init pedit_init_module(void)
 528{
 529        return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
 530}
 531
 532static void __exit pedit_cleanup_module(void)
 533{
 534        tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
 535}
 536
 537module_init(pedit_init_module);
 538module_exit(pedit_cleanup_module);
 539