1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (c) 2015 Jiri Pirko <jiri@resnulli.us> 4 */ 5 6 #include <linux/module.h> 7 #include <linux/init.h> 8 #include <linux/kernel.h> 9 #include <linux/skbuff.h> 10 #include <linux/rtnetlink.h> 11 #include <linux/filter.h> 12 #include <linux/bpf.h> 13 14 #include <net/netlink.h> 15 #include <net/sock.h> 16 #include <net/pkt_sched.h> 17 #include <net/pkt_cls.h> 18 19 #include <linux/tc_act/tc_bpf.h> 20 #include <net/tc_act/tc_bpf.h> 21 22 #define ACT_BPF_NAME_LEN 256 23 24 struct tcf_bpf_cfg { 25 struct bpf_prog *filter; 26 struct sock_filter *bpf_ops; 27 const char *bpf_name; 28 u16 bpf_num_ops; 29 bool is_ebpf; 30 }; 31 32 static struct tc_action_ops act_bpf_ops; 33 34 static int tcf_bpf_act(struct sk_buff *skb, const struct tc_action *act, 35 struct tcf_result *res) 36 { 37 bool at_ingress = skb_at_tc_ingress(skb); 38 struct tcf_bpf *prog = to_bpf(act); 39 struct bpf_prog *filter; 40 int action, filter_res; 41 42 tcf_lastuse_update(&prog->tcf_tm); 43 bstats_update(this_cpu_ptr(prog->common.cpu_bstats), skb); 44 45 filter = rcu_dereference(prog->filter); 46 if (at_ingress) { 47 __skb_push(skb, skb->mac_len); 48 bpf_compute_data_pointers(skb); 49 filter_res = bpf_prog_run(filter, skb); 50 __skb_pull(skb, skb->mac_len); 51 } else { 52 bpf_compute_data_pointers(skb); 53 filter_res = bpf_prog_run(filter, skb); 54 } 55 if (unlikely(!skb->tstamp && skb->mono_delivery_time)) 56 skb->mono_delivery_time = 0; 57 if (skb_sk_is_prefetched(skb) && filter_res != TC_ACT_OK) 58 skb_orphan(skb); 59 60 /* A BPF program may overwrite the default action opcode. 61 * Similarly as in cls_bpf, if filter_res == -1 we use the 62 * default action specified from tc. 63 * 64 * In case a different well-known TC_ACT opcode has been 65 * returned, it will overwrite the default one. 66 * 67 * For everything else that is unknown, TC_ACT_UNSPEC is 68 * returned. 69 */ 70 switch (filter_res) { 71 case TC_ACT_PIPE: 72 case TC_ACT_RECLASSIFY: 73 case TC_ACT_OK: 74 case TC_ACT_REDIRECT: 75 action = filter_res; 76 break; 77 case TC_ACT_SHOT: 78 action = filter_res; 79 qstats_drop_inc(this_cpu_ptr(prog->common.cpu_qstats)); 80 break; 81 case TC_ACT_UNSPEC: 82 action = prog->tcf_action; 83 break; 84 default: 85 action = TC_ACT_UNSPEC; 86 break; 87 } 88 89 return action; 90 } 91 92 static bool tcf_bpf_is_ebpf(const struct tcf_bpf *prog) 93 { 94 return !prog->bpf_ops; 95 } 96 97 static int tcf_bpf_dump_bpf_info(const struct tcf_bpf *prog, 98 struct sk_buff *skb) 99 { 100 struct nlattr *nla; 101 102 if (nla_put_u16(skb, TCA_ACT_BPF_OPS_LEN, prog->bpf_num_ops)) 103 return -EMSGSIZE; 104 105 nla = nla_reserve(skb, TCA_ACT_BPF_OPS, prog->bpf_num_ops * 106 sizeof(struct sock_filter)); 107 if (nla == NULL) 108 return -EMSGSIZE; 109 110 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla)); 111 112 return 0; 113 } 114 115 static int tcf_bpf_dump_ebpf_info(const struct tcf_bpf *prog, 116 struct sk_buff *skb) 117 { 118 struct nlattr *nla; 119 120 if (prog->bpf_name && 121 nla_put_string(skb, TCA_ACT_BPF_NAME, prog->bpf_name)) 122 return -EMSGSIZE; 123 124 if (nla_put_u32(skb, TCA_ACT_BPF_ID, prog->filter->aux->id)) 125 return -EMSGSIZE; 126 127 nla = nla_reserve(skb, TCA_ACT_BPF_TAG, sizeof(prog->filter->tag)); 128 if (nla == NULL) 129 return -EMSGSIZE; 130 131 memcpy(nla_data(nla), prog->filter->tag, nla_len(nla)); 132 133 return 0; 134 } 135 136 static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act, 137 int bind, int ref) 138 { 139 unsigned char *tp = skb_tail_pointer(skb); 140 struct tcf_bpf *prog = to_bpf(act); 141 struct tc_act_bpf opt = { 142 .index = prog->tcf_index, 143 .refcnt = refcount_read(&prog->tcf_refcnt) - ref, 144 .bindcnt = atomic_read(&prog->tcf_bindcnt) - bind, 145 }; 146 struct tcf_t tm; 147 int ret; 148 149 spin_lock_bh(&prog->tcf_lock); 150 opt.action = prog->tcf_action; 151 if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt)) 152 goto nla_put_failure; 153 154 if (tcf_bpf_is_ebpf(prog)) 155 ret = tcf_bpf_dump_ebpf_info(prog, skb); 156 else 157 ret = tcf_bpf_dump_bpf_info(prog, skb); 158 if (ret) 159 goto nla_put_failure; 160 161 tcf_tm_dump(&tm, &prog->tcf_tm); 162 if (nla_put_64bit(skb, TCA_ACT_BPF_TM, sizeof(tm), &tm, 163 TCA_ACT_BPF_PAD)) 164 goto nla_put_failure; 165 166 spin_unlock_bh(&prog->tcf_lock); 167 return skb->len; 168 169 nla_put_failure: 170 spin_unlock_bh(&prog->tcf_lock); 171 nlmsg_trim(skb, tp); 172 return -1; 173 } 174 175 static const struct nla_policy act_bpf_policy[TCA_ACT_BPF_MAX + 1] = { 176 [TCA_ACT_BPF_PARMS] = { .len = sizeof(struct tc_act_bpf) }, 177 [TCA_ACT_BPF_FD] = { .type = NLA_U32 }, 178 [TCA_ACT_BPF_NAME] = { .type = NLA_NUL_STRING, 179 .len = ACT_BPF_NAME_LEN }, 180 [TCA_ACT_BPF_OPS_LEN] = { .type = NLA_U16 }, 181 [TCA_ACT_BPF_OPS] = { .type = NLA_BINARY, 182 .len = sizeof(struct sock_filter) * BPF_MAXINSNS }, 183 }; 184 185 static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg) 186 { 187 struct sock_filter *bpf_ops; 188 struct sock_fprog_kern fprog_tmp; 189 struct bpf_prog *fp; 190 u16 bpf_size, bpf_num_ops; 191 int ret; 192 193 bpf_num_ops = nla_get_u16(tb[TCA_ACT_BPF_OPS_LEN]); 194 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0) 195 return -EINVAL; 196 197 bpf_size = bpf_num_ops * sizeof(*bpf_ops); 198 if (bpf_size != nla_len(tb[TCA_ACT_BPF_OPS])) 199 return -EINVAL; 200 201 bpf_ops = kmemdup(nla_data(tb[TCA_ACT_BPF_OPS]), bpf_size, GFP_KERNEL); 202 if (bpf_ops == NULL) 203 return -ENOMEM; 204 205 fprog_tmp.len = bpf_num_ops; 206 fprog_tmp.filter = bpf_ops; 207 208 ret = bpf_prog_create(&fp, &fprog_tmp); 209 if (ret < 0) { 210 kfree(bpf_ops); 211 return ret; 212 } 213 214 cfg->bpf_ops = bpf_ops; 215 cfg->bpf_num_ops = bpf_num_ops; 216 cfg->filter = fp; 217 cfg->is_ebpf = false; 218 219 return 0; 220 } 221 222 static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg) 223 { 224 struct bpf_prog *fp; 225 char *name = NULL; 226 u32 bpf_fd; 227 228 bpf_fd = nla_get_u32(tb[TCA_ACT_BPF_FD]); 229 230 fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_ACT); 231 if (IS_ERR(fp)) 232 return PTR_ERR(fp); 233 234 if (tb[TCA_ACT_BPF_NAME]) { 235 name = nla_memdup(tb[TCA_ACT_BPF_NAME], GFP_KERNEL); 236 if (!name) { 237 bpf_prog_put(fp); 238 return -ENOMEM; 239 } 240 } 241 242 cfg->bpf_name = name; 243 cfg->filter = fp; 244 cfg->is_ebpf = true; 245 246 return 0; 247 } 248 249 static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg) 250 { 251 struct bpf_prog *filter = cfg->filter; 252 253 if (filter) { 254 if (cfg->is_ebpf) 255 bpf_prog_put(filter); 256 else 257 bpf_prog_destroy(filter); 258 } 259 260 kfree(cfg->bpf_ops); 261 kfree(cfg->bpf_name); 262 } 263 264 static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog, 265 struct tcf_bpf_cfg *cfg) 266 { 267 cfg->is_ebpf = tcf_bpf_is_ebpf(prog); 268 /* updates to prog->filter are prevented, since it's called either 269 * with tcf lock or during final cleanup in rcu callback 270 */ 271 cfg->filter = rcu_dereference_protected(prog->filter, 1); 272 273 cfg->bpf_ops = prog->bpf_ops; 274 cfg->bpf_name = prog->bpf_name; 275 } 276 277 static int tcf_bpf_init(struct net *net, struct nlattr *nla, 278 struct nlattr *est, struct tc_action **act, 279 struct tcf_proto *tp, u32 flags, 280 struct netlink_ext_ack *extack) 281 { 282 struct tc_action_net *tn = net_generic(net, act_bpf_ops.net_id); 283 bool bind = flags & TCA_ACT_FLAGS_BIND; 284 struct nlattr *tb[TCA_ACT_BPF_MAX + 1]; 285 struct tcf_chain *goto_ch = NULL; 286 struct tcf_bpf_cfg cfg, old; 287 struct tc_act_bpf *parm; 288 struct tcf_bpf *prog; 289 bool is_bpf, is_ebpf; 290 int ret, res = 0; 291 u32 index; 292 293 if (!nla) 294 return -EINVAL; 295 296 ret = nla_parse_nested_deprecated(tb, TCA_ACT_BPF_MAX, nla, 297 act_bpf_policy, NULL); 298 if (ret < 0) 299 return ret; 300 301 if (!tb[TCA_ACT_BPF_PARMS]) 302 return -EINVAL; 303 304 parm = nla_data(tb[TCA_ACT_BPF_PARMS]); 305 index = parm->index; 306 ret = tcf_idr_check_alloc(tn, &index, act, bind); 307 if (!ret) { 308 ret = tcf_idr_create(tn, index, est, act, 309 &act_bpf_ops, bind, true, flags); 310 if (ret < 0) { 311 tcf_idr_cleanup(tn, index); 312 return ret; 313 } 314 315 res = ACT_P_CREATED; 316 } else if (ret > 0) { 317 /* Don't override defaults. */ 318 if (bind) 319 return 0; 320 321 if (!(flags & TCA_ACT_FLAGS_REPLACE)) { 322 tcf_idr_release(*act, bind); 323 return -EEXIST; 324 } 325 } else { 326 return ret; 327 } 328 329 ret = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack); 330 if (ret < 0) 331 goto release_idr; 332 333 is_bpf = tb[TCA_ACT_BPF_OPS_LEN] && tb[TCA_ACT_BPF_OPS]; 334 is_ebpf = tb[TCA_ACT_BPF_FD]; 335 336 if (is_bpf == is_ebpf) { 337 ret = -EINVAL; 338 goto put_chain; 339 } 340 341 memset(&cfg, 0, sizeof(cfg)); 342 343 ret = is_bpf ? tcf_bpf_init_from_ops(tb, &cfg) : 344 tcf_bpf_init_from_efd(tb, &cfg); 345 if (ret < 0) 346 goto put_chain; 347 348 prog = to_bpf(*act); 349 350 spin_lock_bh(&prog->tcf_lock); 351 if (res != ACT_P_CREATED) 352 tcf_bpf_prog_fill_cfg(prog, &old); 353 354 prog->bpf_ops = cfg.bpf_ops; 355 prog->bpf_name = cfg.bpf_name; 356 357 if (cfg.bpf_num_ops) 358 prog->bpf_num_ops = cfg.bpf_num_ops; 359 360 goto_ch = tcf_action_set_ctrlact(*act, parm->action, goto_ch); 361 rcu_assign_pointer(prog->filter, cfg.filter); 362 spin_unlock_bh(&prog->tcf_lock); 363 364 if (goto_ch) 365 tcf_chain_put_by_act(goto_ch); 366 367 if (res != ACT_P_CREATED) { 368 /* make sure the program being replaced is no longer executing */ 369 synchronize_rcu(); 370 tcf_bpf_cfg_cleanup(&old); 371 } 372 373 return res; 374 375 put_chain: 376 if (goto_ch) 377 tcf_chain_put_by_act(goto_ch); 378 379 release_idr: 380 tcf_idr_release(*act, bind); 381 return ret; 382 } 383 384 static void tcf_bpf_cleanup(struct tc_action *act) 385 { 386 struct tcf_bpf_cfg tmp; 387 388 tcf_bpf_prog_fill_cfg(to_bpf(act), &tmp); 389 tcf_bpf_cfg_cleanup(&tmp); 390 } 391 392 static struct tc_action_ops act_bpf_ops __read_mostly = { 393 .kind = "bpf", 394 .id = TCA_ID_BPF, 395 .owner = THIS_MODULE, 396 .act = tcf_bpf_act, 397 .dump = tcf_bpf_dump, 398 .cleanup = tcf_bpf_cleanup, 399 .init = tcf_bpf_init, 400 .size = sizeof(struct tcf_bpf), 401 }; 402 403 static __net_init int bpf_init_net(struct net *net) 404 { 405 struct tc_action_net *tn = net_generic(net, act_bpf_ops.net_id); 406 407 return tc_action_net_init(net, tn, &act_bpf_ops); 408 } 409 410 static void __net_exit bpf_exit_net(struct list_head *net_list) 411 { 412 tc_action_net_exit(net_list, act_bpf_ops.net_id); 413 } 414 415 static struct pernet_operations bpf_net_ops = { 416 .init = bpf_init_net, 417 .exit_batch = bpf_exit_net, 418 .id = &act_bpf_ops.net_id, 419 .size = sizeof(struct tc_action_net), 420 }; 421 422 static int __init bpf_init_module(void) 423 { 424 return tcf_register_action(&act_bpf_ops, &bpf_net_ops); 425 } 426 427 static void __exit bpf_cleanup_module(void) 428 { 429 tcf_unregister_action(&act_bpf_ops, &bpf_net_ops); 430 } 431 432 module_init(bpf_init_module); 433 module_exit(bpf_cleanup_module); 434 435 MODULE_AUTHOR("Jiri Pirko <jiri@resnulli.us>"); 436 MODULE_DESCRIPTION("TC BPF based action"); 437 MODULE_LICENSE("GPL v2"); 438