1 // SPDX-License-Identifier: GPL-2.0-only
3 * Berkeley Packet Filter based traffic classifier
5 * Might be used to classify traffic through flexible, user-defined and
6 * possibly JIT-ed BPF filters for traffic control as an alternative to
9 * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
12 #include <linux/module.h>
13 #include <linux/types.h>
14 #include <linux/skbuff.h>
15 #include <linux/filter.h>
16 #include <linux/bpf.h>
17 #include <linux/idr.h>
19 #include <net/rtnetlink.h>
20 #include <net/pkt_cls.h>
23 MODULE_LICENSE("GPL");
24 MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
25 MODULE_DESCRIPTION("TC BPF based classifier");
27 #define CLS_BPF_NAME_LEN 256
28 #define CLS_BPF_SUPPORTED_GEN_FLAGS \
29 (TCA_CLS_FLAGS_SKIP_HW | TCA_CLS_FLAGS_SKIP_SW)
32 struct list_head plist;
33 struct idr handle_idr;
38 struct bpf_prog *filter;
39 struct list_head link;
40 struct tcf_result res;
43 unsigned int in_hw_count;
47 struct sock_filter *bpf_ops;
50 struct rcu_work rwork;
53 static const struct nla_policy bpf_policy[TCA_BPF_MAX + 1] = {
54 [TCA_BPF_CLASSID] = { .type = NLA_U32 },
55 [TCA_BPF_FLAGS] = { .type = NLA_U32 },
56 [TCA_BPF_FLAGS_GEN] = { .type = NLA_U32 },
57 [TCA_BPF_FD] = { .type = NLA_U32 },
58 [TCA_BPF_NAME] = { .type = NLA_NUL_STRING,
59 .len = CLS_BPF_NAME_LEN },
60 [TCA_BPF_OPS_LEN] = { .type = NLA_U16 },
61 [TCA_BPF_OPS] = { .type = NLA_BINARY,
62 .len = sizeof(struct sock_filter) * BPF_MAXINSNS },
65 static int cls_bpf_exec_opcode(int code)
80 static int cls_bpf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
81 struct tcf_result *res)
83 struct cls_bpf_head *head = rcu_dereference_bh(tp->root);
84 bool at_ingress = skb_at_tc_ingress(skb);
85 struct cls_bpf_prog *prog;
88 /* Needed here for accessing maps. */
90 list_for_each_entry_rcu(prog, &head->plist, link) {
93 qdisc_skb_cb(skb)->tc_classid = prog->res.classid;
95 if (tc_skip_sw(prog->gen_flags)) {
96 filter_res = prog->exts_integrated ? TC_ACT_UNSPEC : 0;
97 } else if (at_ingress) {
98 /* It is safe to push/pull even if skb_shared() */
99 __skb_push(skb, skb->mac_len);
100 bpf_compute_data_pointers(skb);
101 filter_res = BPF_PROG_RUN(prog->filter, skb);
102 __skb_pull(skb, skb->mac_len);
104 bpf_compute_data_pointers(skb);
105 filter_res = BPF_PROG_RUN(prog->filter, skb);
108 if (prog->exts_integrated) {
110 res->classid = TC_H_MAJ(prog->res.classid) |
111 qdisc_skb_cb(skb)->tc_classid;
113 ret = cls_bpf_exec_opcode(filter_res);
114 if (ret == TC_ACT_UNSPEC)
121 if (filter_res != -1) {
123 res->classid = filter_res;
128 ret = tcf_exts_exec(skb, &prog->exts, res);
139 static bool cls_bpf_is_ebpf(const struct cls_bpf_prog *prog)
141 return !prog->bpf_ops;
144 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
145 struct cls_bpf_prog *oldprog,
146 struct netlink_ext_ack *extack)
148 struct tcf_block *block = tp->chain->block;
149 struct tc_cls_bpf_offload cls_bpf = {};
150 struct cls_bpf_prog *obj;
154 skip_sw = prog && tc_skip_sw(prog->gen_flags);
155 obj = prog ?: oldprog;
157 tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags, extack);
158 cls_bpf.command = TC_CLSBPF_OFFLOAD;
159 cls_bpf.exts = &obj->exts;
160 cls_bpf.prog = prog ? prog->filter : NULL;
161 cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
162 cls_bpf.name = obj->bpf_name;
163 cls_bpf.exts_integrated = obj->exts_integrated;
166 err = tc_setup_cb_replace(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
167 skip_sw, &oldprog->gen_flags,
168 &oldprog->in_hw_count,
169 &prog->gen_flags, &prog->in_hw_count,
172 err = tc_setup_cb_add(block, tp, TC_SETUP_CLSBPF, &cls_bpf,
173 skip_sw, &prog->gen_flags,
174 &prog->in_hw_count, true);
177 cls_bpf_offload_cmd(tp, oldprog, prog, extack);
181 if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
187 static u32 cls_bpf_flags(u32 flags)
189 return flags & CLS_BPF_SUPPORTED_GEN_FLAGS;
192 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
193 struct cls_bpf_prog *oldprog,
194 struct netlink_ext_ack *extack)
196 if (prog && oldprog &&
197 cls_bpf_flags(prog->gen_flags) !=
198 cls_bpf_flags(oldprog->gen_flags))
201 if (prog && tc_skip_hw(prog->gen_flags))
203 if (oldprog && tc_skip_hw(oldprog->gen_flags))
205 if (!prog && !oldprog)
208 return cls_bpf_offload_cmd(tp, prog, oldprog, extack);
211 static void cls_bpf_stop_offload(struct tcf_proto *tp,
212 struct cls_bpf_prog *prog,
213 struct netlink_ext_ack *extack)
217 err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
219 pr_err("Stopping hardware offload failed: %d\n", err);
222 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
223 struct cls_bpf_prog *prog)
225 struct tcf_block *block = tp->chain->block;
226 struct tc_cls_bpf_offload cls_bpf = {};
228 tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
229 cls_bpf.command = TC_CLSBPF_STATS;
230 cls_bpf.exts = &prog->exts;
231 cls_bpf.prog = prog->filter;
232 cls_bpf.name = prog->bpf_name;
233 cls_bpf.exts_integrated = prog->exts_integrated;
235 tc_setup_cb_call(block, TC_SETUP_CLSBPF, &cls_bpf, false, true);
238 static int cls_bpf_init(struct tcf_proto *tp)
240 struct cls_bpf_head *head;
242 head = kzalloc(sizeof(*head), GFP_KERNEL);
246 INIT_LIST_HEAD_RCU(&head->plist);
247 idr_init(&head->handle_idr);
248 rcu_assign_pointer(tp->root, head);
253 static void cls_bpf_free_parms(struct cls_bpf_prog *prog)
255 if (cls_bpf_is_ebpf(prog))
256 bpf_prog_put(prog->filter);
258 bpf_prog_destroy(prog->filter);
260 kfree(prog->bpf_name);
261 kfree(prog->bpf_ops);
264 static void __cls_bpf_delete_prog(struct cls_bpf_prog *prog)
266 tcf_exts_destroy(&prog->exts);
267 tcf_exts_put_net(&prog->exts);
269 cls_bpf_free_parms(prog);
273 static void cls_bpf_delete_prog_work(struct work_struct *work)
275 struct cls_bpf_prog *prog = container_of(to_rcu_work(work),
279 __cls_bpf_delete_prog(prog);
283 static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
284 struct netlink_ext_ack *extack)
286 struct cls_bpf_head *head = rtnl_dereference(tp->root);
288 idr_remove(&head->handle_idr, prog->handle);
289 cls_bpf_stop_offload(tp, prog, extack);
290 list_del_rcu(&prog->link);
291 tcf_unbind_filter(tp, &prog->res);
292 if (tcf_exts_get_net(&prog->exts))
293 tcf_queue_work(&prog->rwork, cls_bpf_delete_prog_work);
295 __cls_bpf_delete_prog(prog);
298 static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
299 bool rtnl_held, struct netlink_ext_ack *extack)
301 struct cls_bpf_head *head = rtnl_dereference(tp->root);
303 __cls_bpf_delete(tp, arg, extack);
304 *last = list_empty(&head->plist);
308 static void cls_bpf_destroy(struct tcf_proto *tp, bool rtnl_held,
309 struct netlink_ext_ack *extack)
311 struct cls_bpf_head *head = rtnl_dereference(tp->root);
312 struct cls_bpf_prog *prog, *tmp;
314 list_for_each_entry_safe(prog, tmp, &head->plist, link)
315 __cls_bpf_delete(tp, prog, extack);
317 idr_destroy(&head->handle_idr);
318 kfree_rcu(head, rcu);
321 static void *cls_bpf_get(struct tcf_proto *tp, u32 handle)
323 struct cls_bpf_head *head = rtnl_dereference(tp->root);
324 struct cls_bpf_prog *prog;
326 list_for_each_entry(prog, &head->plist, link) {
327 if (prog->handle == handle)
334 static int cls_bpf_prog_from_ops(struct nlattr **tb, struct cls_bpf_prog *prog)
336 struct sock_filter *bpf_ops;
337 struct sock_fprog_kern fprog_tmp;
339 u16 bpf_size, bpf_num_ops;
342 bpf_num_ops = nla_get_u16(tb[TCA_BPF_OPS_LEN]);
343 if (bpf_num_ops > BPF_MAXINSNS || bpf_num_ops == 0)
346 bpf_size = bpf_num_ops * sizeof(*bpf_ops);
347 if (bpf_size != nla_len(tb[TCA_BPF_OPS]))
350 bpf_ops = kmemdup(nla_data(tb[TCA_BPF_OPS]), bpf_size, GFP_KERNEL);
354 fprog_tmp.len = bpf_num_ops;
355 fprog_tmp.filter = bpf_ops;
357 ret = bpf_prog_create(&fp, &fprog_tmp);
363 prog->bpf_ops = bpf_ops;
364 prog->bpf_num_ops = bpf_num_ops;
365 prog->bpf_name = NULL;
371 static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
372 u32 gen_flags, const struct tcf_proto *tp)
379 bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
380 skip_sw = gen_flags & TCA_CLS_FLAGS_SKIP_SW;
382 fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS, skip_sw);
386 if (tb[TCA_BPF_NAME]) {
387 name = nla_memdup(tb[TCA_BPF_NAME], GFP_KERNEL);
394 prog->bpf_ops = NULL;
395 prog->bpf_name = name;
399 tcf_block_netif_keep_dst(tp->chain->block);
404 static int cls_bpf_set_parms(struct net *net, struct tcf_proto *tp,
405 struct cls_bpf_prog *prog, unsigned long base,
406 struct nlattr **tb, struct nlattr *est, bool ovr,
407 struct netlink_ext_ack *extack)
409 bool is_bpf, is_ebpf, have_exts = false;
413 is_bpf = tb[TCA_BPF_OPS_LEN] && tb[TCA_BPF_OPS];
414 is_ebpf = tb[TCA_BPF_FD];
415 if ((!is_bpf && !is_ebpf) || (is_bpf && is_ebpf))
418 ret = tcf_exts_validate(net, tp, tb, est, &prog->exts, ovr, true,
423 if (tb[TCA_BPF_FLAGS]) {
424 u32 bpf_flags = nla_get_u32(tb[TCA_BPF_FLAGS]);
426 if (bpf_flags & ~TCA_BPF_FLAG_ACT_DIRECT)
429 have_exts = bpf_flags & TCA_BPF_FLAG_ACT_DIRECT;
431 if (tb[TCA_BPF_FLAGS_GEN]) {
432 gen_flags = nla_get_u32(tb[TCA_BPF_FLAGS_GEN]);
433 if (gen_flags & ~CLS_BPF_SUPPORTED_GEN_FLAGS ||
434 !tc_flags_valid(gen_flags))
438 prog->exts_integrated = have_exts;
439 prog->gen_flags = gen_flags;
441 ret = is_bpf ? cls_bpf_prog_from_ops(tb, prog) :
442 cls_bpf_prog_from_efd(tb, prog, gen_flags, tp);
446 if (tb[TCA_BPF_CLASSID]) {
447 prog->res.classid = nla_get_u32(tb[TCA_BPF_CLASSID]);
448 tcf_bind_filter(tp, &prog->res, base);
454 static int cls_bpf_change(struct net *net, struct sk_buff *in_skb,
455 struct tcf_proto *tp, unsigned long base,
456 u32 handle, struct nlattr **tca,
457 void **arg, bool ovr, bool rtnl_held,
458 struct netlink_ext_ack *extack)
460 struct cls_bpf_head *head = rtnl_dereference(tp->root);
461 struct cls_bpf_prog *oldprog = *arg;
462 struct nlattr *tb[TCA_BPF_MAX + 1];
463 struct cls_bpf_prog *prog;
466 if (tca[TCA_OPTIONS] == NULL)
469 ret = nla_parse_nested_deprecated(tb, TCA_BPF_MAX, tca[TCA_OPTIONS],
474 prog = kzalloc(sizeof(*prog), GFP_KERNEL);
478 ret = tcf_exts_init(&prog->exts, net, TCA_BPF_ACT, TCA_BPF_POLICE);
483 if (handle && oldprog->handle != handle) {
491 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
492 INT_MAX, GFP_KERNEL);
493 } else if (!oldprog) {
494 ret = idr_alloc_u32(&head->handle_idr, prog, &handle,
500 prog->handle = handle;
502 ret = cls_bpf_set_parms(net, tp, prog, base, tb, tca[TCA_RATE], ovr,
507 ret = cls_bpf_offload(tp, prog, oldprog, extack);
511 if (!tc_in_hw(prog->gen_flags))
512 prog->gen_flags |= TCA_CLS_FLAGS_NOT_IN_HW;
515 idr_replace(&head->handle_idr, prog, handle);
516 list_replace_rcu(&oldprog->link, &prog->link);
517 tcf_unbind_filter(tp, &oldprog->res);
518 tcf_exts_get_net(&oldprog->exts);
519 tcf_queue_work(&oldprog->rwork, cls_bpf_delete_prog_work);
521 list_add_rcu(&prog->link, &head->plist);
528 cls_bpf_free_parms(prog);
531 idr_remove(&head->handle_idr, prog->handle);
533 tcf_exts_destroy(&prog->exts);
538 static int cls_bpf_dump_bpf_info(const struct cls_bpf_prog *prog,
543 if (nla_put_u16(skb, TCA_BPF_OPS_LEN, prog->bpf_num_ops))
546 nla = nla_reserve(skb, TCA_BPF_OPS, prog->bpf_num_ops *
547 sizeof(struct sock_filter));
551 memcpy(nla_data(nla), prog->bpf_ops, nla_len(nla));
556 static int cls_bpf_dump_ebpf_info(const struct cls_bpf_prog *prog,
561 if (prog->bpf_name &&
562 nla_put_string(skb, TCA_BPF_NAME, prog->bpf_name))
565 if (nla_put_u32(skb, TCA_BPF_ID, prog->filter->aux->id))
568 nla = nla_reserve(skb, TCA_BPF_TAG, sizeof(prog->filter->tag));
572 memcpy(nla_data(nla), prog->filter->tag, nla_len(nla));
577 static int cls_bpf_dump(struct net *net, struct tcf_proto *tp, void *fh,
578 struct sk_buff *skb, struct tcmsg *tm, bool rtnl_held)
580 struct cls_bpf_prog *prog = fh;
588 tm->tcm_handle = prog->handle;
590 cls_bpf_offload_update_stats(tp, prog);
592 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
594 goto nla_put_failure;
596 if (prog->res.classid &&
597 nla_put_u32(skb, TCA_BPF_CLASSID, prog->res.classid))
598 goto nla_put_failure;
600 if (cls_bpf_is_ebpf(prog))
601 ret = cls_bpf_dump_ebpf_info(prog, skb);
603 ret = cls_bpf_dump_bpf_info(prog, skb);
605 goto nla_put_failure;
607 if (tcf_exts_dump(skb, &prog->exts) < 0)
608 goto nla_put_failure;
610 if (prog->exts_integrated)
611 bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
612 if (bpf_flags && nla_put_u32(skb, TCA_BPF_FLAGS, bpf_flags))
613 goto nla_put_failure;
614 if (prog->gen_flags &&
615 nla_put_u32(skb, TCA_BPF_FLAGS_GEN, prog->gen_flags))
616 goto nla_put_failure;
618 nla_nest_end(skb, nest);
620 if (tcf_exts_dump_stats(skb, &prog->exts) < 0)
621 goto nla_put_failure;
626 nla_nest_cancel(skb, nest);
630 static void cls_bpf_bind_class(void *fh, u32 classid, unsigned long cl)
632 struct cls_bpf_prog *prog = fh;
634 if (prog && prog->res.classid == classid)
635 prog->res.class = cl;
638 static void cls_bpf_walk(struct tcf_proto *tp, struct tcf_walker *arg,
641 struct cls_bpf_head *head = rtnl_dereference(tp->root);
642 struct cls_bpf_prog *prog;
644 list_for_each_entry(prog, &head->plist, link) {
645 if (arg->count < arg->skip)
647 if (arg->fn(tp, prog, arg) < 0) {
656 static int cls_bpf_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb,
657 void *cb_priv, struct netlink_ext_ack *extack)
659 struct cls_bpf_head *head = rtnl_dereference(tp->root);
660 struct tcf_block *block = tp->chain->block;
661 struct tc_cls_bpf_offload cls_bpf = {};
662 struct cls_bpf_prog *prog;
665 list_for_each_entry(prog, &head->plist, link) {
666 if (tc_skip_hw(prog->gen_flags))
669 tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags,
671 cls_bpf.command = TC_CLSBPF_OFFLOAD;
672 cls_bpf.exts = &prog->exts;
673 cls_bpf.prog = add ? prog->filter : NULL;
674 cls_bpf.oldprog = add ? NULL : prog->filter;
675 cls_bpf.name = prog->bpf_name;
676 cls_bpf.exts_integrated = prog->exts_integrated;
678 err = tc_setup_cb_reoffload(block, tp, add, cb, TC_SETUP_CLSBPF,
679 &cls_bpf, cb_priv, &prog->gen_flags,
688 static struct tcf_proto_ops cls_bpf_ops __read_mostly = {
690 .owner = THIS_MODULE,
691 .classify = cls_bpf_classify,
692 .init = cls_bpf_init,
693 .destroy = cls_bpf_destroy,
695 .change = cls_bpf_change,
696 .delete = cls_bpf_delete,
697 .walk = cls_bpf_walk,
698 .reoffload = cls_bpf_reoffload,
699 .dump = cls_bpf_dump,
700 .bind_class = cls_bpf_bind_class,
703 static int __init cls_bpf_init_mod(void)
705 return register_tcf_proto_ops(&cls_bpf_ops);
708 static void __exit cls_bpf_exit_mod(void)
710 unregister_tcf_proto_ops(&cls_bpf_ops);
713 module_init(cls_bpf_init_mod);
714 module_exit(cls_bpf_exit_mod);