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19#include <linux/bitops.h>
20#include <linux/bpf.h>
21#include <linux/filter.h>
22#include <linux/ptr_ring.h>
23#include <net/xdp.h>
24
25#include <linux/sched.h>
26#include <linux/workqueue.h>
27#include <linux/kthread.h>
28#include <linux/capability.h>
29#include <trace/events/xdp.h>
30
31#include <linux/netdevice.h>
32#include <linux/etherdevice.h>
33
34
35
36
37
38
39
40
41#define CPU_MAP_BULK_SIZE 8
42struct bpf_cpu_map_entry;
43struct bpf_cpu_map;
44
45struct xdp_bulk_queue {
46 void *q[CPU_MAP_BULK_SIZE];
47 struct list_head flush_node;
48 struct bpf_cpu_map_entry *obj;
49 unsigned int count;
50};
51
52
53struct bpf_cpu_map_entry {
54 u32 cpu;
55 int map_id;
56
57
58 struct xdp_bulk_queue __percpu *bulkq;
59
60 struct bpf_cpu_map *cmap;
61
62
63 struct ptr_ring *queue;
64 struct task_struct *kthread;
65
66 struct bpf_cpumap_val value;
67 struct bpf_prog *prog;
68
69 atomic_t refcnt;
70 struct rcu_head rcu;
71
72 struct work_struct kthread_stop_wq;
73};
74
75struct bpf_cpu_map {
76 struct bpf_map map;
77
78 struct bpf_cpu_map_entry __rcu **cpu_map;
79};
80
81static DEFINE_PER_CPU(struct list_head, cpu_map_flush_list);
82
83static struct bpf_map *cpu_map_alloc(union bpf_attr *attr)
84{
85 u32 value_size = attr->value_size;
86 struct bpf_cpu_map *cmap;
87 int err = -ENOMEM;
88
89 if (!bpf_capable())
90 return ERR_PTR(-EPERM);
91
92
93 if (attr->max_entries == 0 || attr->key_size != 4 ||
94 (value_size != offsetofend(struct bpf_cpumap_val, qsize) &&
95 value_size != offsetofend(struct bpf_cpumap_val, bpf_prog.fd)) ||
96 attr->map_flags & ~BPF_F_NUMA_NODE)
97 return ERR_PTR(-EINVAL);
98
99 cmap = kzalloc(sizeof(*cmap), GFP_USER | __GFP_ACCOUNT);
100 if (!cmap)
101 return ERR_PTR(-ENOMEM);
102
103 bpf_map_init_from_attr(&cmap->map, attr);
104
105
106 if (cmap->map.max_entries > NR_CPUS) {
107 err = -E2BIG;
108 goto free_cmap;
109 }
110
111
112 cmap->cpu_map = bpf_map_area_alloc(cmap->map.max_entries *
113 sizeof(struct bpf_cpu_map_entry *),
114 cmap->map.numa_node);
115 if (!cmap->cpu_map)
116 goto free_cmap;
117
118 return &cmap->map;
119free_cmap:
120 kfree(cmap);
121 return ERR_PTR(err);
122}
123
124static void get_cpu_map_entry(struct bpf_cpu_map_entry *rcpu)
125{
126 atomic_inc(&rcpu->refcnt);
127}
128
129
130static void cpu_map_kthread_stop(struct work_struct *work)
131{
132 struct bpf_cpu_map_entry *rcpu;
133
134 rcpu = container_of(work, struct bpf_cpu_map_entry, kthread_stop_wq);
135
136
137
138
139 rcu_barrier();
140
141
142 kthread_stop(rcpu->kthread);
143}
144
145static void __cpu_map_ring_cleanup(struct ptr_ring *ring)
146{
147
148
149
150
151
152 struct xdp_frame *xdpf;
153
154 while ((xdpf = ptr_ring_consume(ring)))
155 if (WARN_ON_ONCE(xdpf))
156 xdp_return_frame(xdpf);
157}
158
159static void put_cpu_map_entry(struct bpf_cpu_map_entry *rcpu)
160{
161 if (atomic_dec_and_test(&rcpu->refcnt)) {
162 if (rcpu->prog)
163 bpf_prog_put(rcpu->prog);
164
165 __cpu_map_ring_cleanup(rcpu->queue);
166 ptr_ring_cleanup(rcpu->queue, NULL);
167 kfree(rcpu->queue);
168 kfree(rcpu);
169 }
170}
171
172static void cpu_map_bpf_prog_run_skb(struct bpf_cpu_map_entry *rcpu,
173 struct list_head *listp,
174 struct xdp_cpumap_stats *stats)
175{
176 struct sk_buff *skb, *tmp;
177 struct xdp_buff xdp;
178 u32 act;
179 int err;
180
181 list_for_each_entry_safe(skb, tmp, listp, list) {
182 act = bpf_prog_run_generic_xdp(skb, &xdp, rcpu->prog);
183 switch (act) {
184 case XDP_PASS:
185 break;
186 case XDP_REDIRECT:
187 skb_list_del_init(skb);
188 err = xdp_do_generic_redirect(skb->dev, skb, &xdp,
189 rcpu->prog);
190 if (unlikely(err)) {
191 kfree_skb(skb);
192 stats->drop++;
193 } else {
194 stats->redirect++;
195 }
196 return;
197 default:
198 bpf_warn_invalid_xdp_action(act);
199 fallthrough;
200 case XDP_ABORTED:
201 trace_xdp_exception(skb->dev, rcpu->prog, act);
202 fallthrough;
203 case XDP_DROP:
204 skb_list_del_init(skb);
205 kfree_skb(skb);
206 stats->drop++;
207 return;
208 }
209 }
210}
211
212static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu,
213 void **frames, int n,
214 struct xdp_cpumap_stats *stats)
215{
216 struct xdp_rxq_info rxq;
217 struct xdp_buff xdp;
218 int i, nframes = 0;
219
220 xdp_set_return_frame_no_direct();
221 xdp.rxq = &rxq;
222
223 for (i = 0; i < n; i++) {
224 struct xdp_frame *xdpf = frames[i];
225 u32 act;
226 int err;
227
228 rxq.dev = xdpf->dev_rx;
229 rxq.mem = xdpf->mem;
230
231
232 xdp_convert_frame_to_buff(xdpf, &xdp);
233
234 act = bpf_prog_run_xdp(rcpu->prog, &xdp);
235 switch (act) {
236 case XDP_PASS:
237 err = xdp_update_frame_from_buff(&xdp, xdpf);
238 if (err < 0) {
239 xdp_return_frame(xdpf);
240 stats->drop++;
241 } else {
242 frames[nframes++] = xdpf;
243 stats->pass++;
244 }
245 break;
246 case XDP_REDIRECT:
247 err = xdp_do_redirect(xdpf->dev_rx, &xdp,
248 rcpu->prog);
249 if (unlikely(err)) {
250 xdp_return_frame(xdpf);
251 stats->drop++;
252 } else {
253 stats->redirect++;
254 }
255 break;
256 default:
257 bpf_warn_invalid_xdp_action(act);
258 fallthrough;
259 case XDP_DROP:
260 xdp_return_frame(xdpf);
261 stats->drop++;
262 break;
263 }
264 }
265
266 xdp_clear_return_frame_no_direct();
267
268 return nframes;
269}
270
271#define CPUMAP_BATCH 8
272
273static int cpu_map_bpf_prog_run(struct bpf_cpu_map_entry *rcpu, void **frames,
274 int xdp_n, struct xdp_cpumap_stats *stats,
275 struct list_head *list)
276{
277 int nframes;
278
279 if (!rcpu->prog)
280 return xdp_n;
281
282 rcu_read_lock_bh();
283
284 nframes = cpu_map_bpf_prog_run_xdp(rcpu, frames, xdp_n, stats);
285
286 if (stats->redirect)
287 xdp_do_flush();
288
289 if (unlikely(!list_empty(list)))
290 cpu_map_bpf_prog_run_skb(rcpu, list, stats);
291
292 rcu_read_unlock_bh();
293
294 return nframes;
295}
296
297
298static int cpu_map_kthread_run(void *data)
299{
300 struct bpf_cpu_map_entry *rcpu = data;
301
302 set_current_state(TASK_INTERRUPTIBLE);
303
304
305
306
307
308
309 while (!kthread_should_stop() || !__ptr_ring_empty(rcpu->queue)) {
310 struct xdp_cpumap_stats stats = {};
311 unsigned int kmem_alloc_drops = 0, sched = 0;
312 gfp_t gfp = __GFP_ZERO | GFP_ATOMIC;
313 int i, n, m, nframes, xdp_n;
314 void *frames[CPUMAP_BATCH];
315 void *skbs[CPUMAP_BATCH];
316 LIST_HEAD(list);
317
318
319 if (__ptr_ring_empty(rcpu->queue)) {
320 set_current_state(TASK_INTERRUPTIBLE);
321
322 if (__ptr_ring_empty(rcpu->queue)) {
323 schedule();
324 sched = 1;
325 } else {
326 __set_current_state(TASK_RUNNING);
327 }
328 } else {
329 sched = cond_resched();
330 }
331
332
333
334
335
336
337 n = __ptr_ring_consume_batched(rcpu->queue, frames,
338 CPUMAP_BATCH);
339 for (i = 0, xdp_n = 0; i < n; i++) {
340 void *f = frames[i];
341 struct page *page;
342
343 if (unlikely(__ptr_test_bit(0, &f))) {
344 struct sk_buff *skb = f;
345
346 __ptr_clear_bit(0, &skb);
347 list_add_tail(&skb->list, &list);
348 continue;
349 }
350
351 frames[xdp_n++] = f;
352 page = virt_to_page(f);
353
354
355
356
357
358 prefetchw(page);
359 }
360
361
362 nframes = cpu_map_bpf_prog_run(rcpu, frames, xdp_n, &stats, &list);
363 if (nframes) {
364 m = kmem_cache_alloc_bulk(skbuff_head_cache, gfp, nframes, skbs);
365 if (unlikely(m == 0)) {
366 for (i = 0; i < nframes; i++)
367 skbs[i] = NULL;
368 kmem_alloc_drops += nframes;
369 }
370 }
371
372 local_bh_disable();
373 for (i = 0; i < nframes; i++) {
374 struct xdp_frame *xdpf = frames[i];
375 struct sk_buff *skb = skbs[i];
376
377 skb = __xdp_build_skb_from_frame(xdpf, skb,
378 xdpf->dev_rx);
379 if (!skb) {
380 xdp_return_frame(xdpf);
381 continue;
382 }
383
384 list_add_tail(&skb->list, &list);
385 }
386 netif_receive_skb_list(&list);
387
388
389 trace_xdp_cpumap_kthread(rcpu->map_id, n, kmem_alloc_drops,
390 sched, &stats);
391
392 local_bh_enable();
393 }
394 __set_current_state(TASK_RUNNING);
395
396 put_cpu_map_entry(rcpu);
397 return 0;
398}
399
400static int __cpu_map_load_bpf_program(struct bpf_cpu_map_entry *rcpu, int fd)
401{
402 struct bpf_prog *prog;
403
404 prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_XDP);
405 if (IS_ERR(prog))
406 return PTR_ERR(prog);
407
408 if (prog->expected_attach_type != BPF_XDP_CPUMAP) {
409 bpf_prog_put(prog);
410 return -EINVAL;
411 }
412
413 rcpu->value.bpf_prog.id = prog->aux->id;
414 rcpu->prog = prog;
415
416 return 0;
417}
418
419static struct bpf_cpu_map_entry *
420__cpu_map_entry_alloc(struct bpf_map *map, struct bpf_cpumap_val *value,
421 u32 cpu)
422{
423 int numa, err, i, fd = value->bpf_prog.fd;
424 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
425 struct bpf_cpu_map_entry *rcpu;
426 struct xdp_bulk_queue *bq;
427
428
429 numa = cpu_to_node(cpu);
430
431 rcpu = bpf_map_kmalloc_node(map, sizeof(*rcpu), gfp | __GFP_ZERO, numa);
432 if (!rcpu)
433 return NULL;
434
435
436 rcpu->bulkq = bpf_map_alloc_percpu(map, sizeof(*rcpu->bulkq),
437 sizeof(void *), gfp);
438 if (!rcpu->bulkq)
439 goto free_rcu;
440
441 for_each_possible_cpu(i) {
442 bq = per_cpu_ptr(rcpu->bulkq, i);
443 bq->obj = rcpu;
444 }
445
446
447 rcpu->queue = bpf_map_kmalloc_node(map, sizeof(*rcpu->queue), gfp,
448 numa);
449 if (!rcpu->queue)
450 goto free_bulkq;
451
452 err = ptr_ring_init(rcpu->queue, value->qsize, gfp);
453 if (err)
454 goto free_queue;
455
456 rcpu->cpu = cpu;
457 rcpu->map_id = map->id;
458 rcpu->value.qsize = value->qsize;
459
460 if (fd > 0 && __cpu_map_load_bpf_program(rcpu, fd))
461 goto free_ptr_ring;
462
463
464 rcpu->kthread = kthread_create_on_node(cpu_map_kthread_run, rcpu, numa,
465 "cpumap/%d/map:%d", cpu,
466 map->id);
467 if (IS_ERR(rcpu->kthread))
468 goto free_prog;
469
470 get_cpu_map_entry(rcpu);
471 get_cpu_map_entry(rcpu);
472
473
474 kthread_bind(rcpu->kthread, cpu);
475 wake_up_process(rcpu->kthread);
476
477 return rcpu;
478
479free_prog:
480 if (rcpu->prog)
481 bpf_prog_put(rcpu->prog);
482free_ptr_ring:
483 ptr_ring_cleanup(rcpu->queue, NULL);
484free_queue:
485 kfree(rcpu->queue);
486free_bulkq:
487 free_percpu(rcpu->bulkq);
488free_rcu:
489 kfree(rcpu);
490 return NULL;
491}
492
493static void __cpu_map_entry_free(struct rcu_head *rcu)
494{
495 struct bpf_cpu_map_entry *rcpu;
496
497
498
499
500
501
502 rcpu = container_of(rcu, struct bpf_cpu_map_entry, rcu);
503
504 free_percpu(rcpu->bulkq);
505
506 put_cpu_map_entry(rcpu);
507}
508
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525
526
527
528static void __cpu_map_entry_replace(struct bpf_cpu_map *cmap,
529 u32 key_cpu, struct bpf_cpu_map_entry *rcpu)
530{
531 struct bpf_cpu_map_entry *old_rcpu;
532
533 old_rcpu = unrcu_pointer(xchg(&cmap->cpu_map[key_cpu], RCU_INITIALIZER(rcpu)));
534 if (old_rcpu) {
535 call_rcu(&old_rcpu->rcu, __cpu_map_entry_free);
536 INIT_WORK(&old_rcpu->kthread_stop_wq, cpu_map_kthread_stop);
537 schedule_work(&old_rcpu->kthread_stop_wq);
538 }
539}
540
541static int cpu_map_delete_elem(struct bpf_map *map, void *key)
542{
543 struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
544 u32 key_cpu = *(u32 *)key;
545
546 if (key_cpu >= map->max_entries)
547 return -EINVAL;
548
549
550 __cpu_map_entry_replace(cmap, key_cpu, NULL);
551 return 0;
552}
553
554static int cpu_map_update_elem(struct bpf_map *map, void *key, void *value,
555 u64 map_flags)
556{
557 struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
558 struct bpf_cpumap_val cpumap_value = {};
559 struct bpf_cpu_map_entry *rcpu;
560
561 u32 key_cpu = *(u32 *)key;
562
563 memcpy(&cpumap_value, value, map->value_size);
564
565 if (unlikely(map_flags > BPF_EXIST))
566 return -EINVAL;
567 if (unlikely(key_cpu >= cmap->map.max_entries))
568 return -E2BIG;
569 if (unlikely(map_flags == BPF_NOEXIST))
570 return -EEXIST;
571 if (unlikely(cpumap_value.qsize > 16384))
572 return -EOVERFLOW;
573
574
575 if (key_cpu >= nr_cpumask_bits || !cpu_possible(key_cpu))
576 return -ENODEV;
577
578 if (cpumap_value.qsize == 0) {
579 rcpu = NULL;
580 } else {
581
582 rcpu = __cpu_map_entry_alloc(map, &cpumap_value, key_cpu);
583 if (!rcpu)
584 return -ENOMEM;
585 rcpu->cmap = cmap;
586 }
587 rcu_read_lock();
588 __cpu_map_entry_replace(cmap, key_cpu, rcpu);
589 rcu_read_unlock();
590 return 0;
591}
592
593static void cpu_map_free(struct bpf_map *map)
594{
595 struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
596 u32 i;
597
598
599
600
601
602
603
604
605
606
607 synchronize_rcu();
608
609
610
611
612 for (i = 0; i < cmap->map.max_entries; i++) {
613 struct bpf_cpu_map_entry *rcpu;
614
615 rcpu = rcu_dereference_raw(cmap->cpu_map[i]);
616 if (!rcpu)
617 continue;
618
619
620 __cpu_map_entry_replace(cmap, i, NULL);
621 }
622 bpf_map_area_free(cmap->cpu_map);
623 kfree(cmap);
624}
625
626
627
628
629
630static void *__cpu_map_lookup_elem(struct bpf_map *map, u32 key)
631{
632 struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
633 struct bpf_cpu_map_entry *rcpu;
634
635 if (key >= map->max_entries)
636 return NULL;
637
638 rcpu = rcu_dereference_check(cmap->cpu_map[key],
639 rcu_read_lock_bh_held());
640 return rcpu;
641}
642
643static void *cpu_map_lookup_elem(struct bpf_map *map, void *key)
644{
645 struct bpf_cpu_map_entry *rcpu =
646 __cpu_map_lookup_elem(map, *(u32 *)key);
647
648 return rcpu ? &rcpu->value : NULL;
649}
650
651static int cpu_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
652{
653 struct bpf_cpu_map *cmap = container_of(map, struct bpf_cpu_map, map);
654 u32 index = key ? *(u32 *)key : U32_MAX;
655 u32 *next = next_key;
656
657 if (index >= cmap->map.max_entries) {
658 *next = 0;
659 return 0;
660 }
661
662 if (index == cmap->map.max_entries - 1)
663 return -ENOENT;
664 *next = index + 1;
665 return 0;
666}
667
668static int cpu_map_redirect(struct bpf_map *map, u32 ifindex, u64 flags)
669{
670 return __bpf_xdp_redirect_map(map, ifindex, flags, 0,
671 __cpu_map_lookup_elem);
672}
673
674static int cpu_map_btf_id;
675const struct bpf_map_ops cpu_map_ops = {
676 .map_meta_equal = bpf_map_meta_equal,
677 .map_alloc = cpu_map_alloc,
678 .map_free = cpu_map_free,
679 .map_delete_elem = cpu_map_delete_elem,
680 .map_update_elem = cpu_map_update_elem,
681 .map_lookup_elem = cpu_map_lookup_elem,
682 .map_get_next_key = cpu_map_get_next_key,
683 .map_check_btf = map_check_no_btf,
684 .map_btf_name = "bpf_cpu_map",
685 .map_btf_id = &cpu_map_btf_id,
686 .map_redirect = cpu_map_redirect,
687};
688
689static void bq_flush_to_queue(struct xdp_bulk_queue *bq)
690{
691 struct bpf_cpu_map_entry *rcpu = bq->obj;
692 unsigned int processed = 0, drops = 0;
693 const int to_cpu = rcpu->cpu;
694 struct ptr_ring *q;
695 int i;
696
697 if (unlikely(!bq->count))
698 return;
699
700 q = rcpu->queue;
701 spin_lock(&q->producer_lock);
702
703 for (i = 0; i < bq->count; i++) {
704 struct xdp_frame *xdpf = bq->q[i];
705 int err;
706
707 err = __ptr_ring_produce(q, xdpf);
708 if (err) {
709 drops++;
710 xdp_return_frame_rx_napi(xdpf);
711 }
712 processed++;
713 }
714 bq->count = 0;
715 spin_unlock(&q->producer_lock);
716
717 __list_del_clearprev(&bq->flush_node);
718
719
720 trace_xdp_cpumap_enqueue(rcpu->map_id, processed, drops, to_cpu);
721}
722
723
724
725
726static void bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf)
727{
728 struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list);
729 struct xdp_bulk_queue *bq = this_cpu_ptr(rcpu->bulkq);
730
731 if (unlikely(bq->count == CPU_MAP_BULK_SIZE))
732 bq_flush_to_queue(bq);
733
734
735
736
737
738
739
740
741
742
743 bq->q[bq->count++] = xdpf;
744
745 if (!bq->flush_node.prev)
746 list_add(&bq->flush_node, flush_list);
747}
748
749int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,
750 struct net_device *dev_rx)
751{
752 struct xdp_frame *xdpf;
753
754 xdpf = xdp_convert_buff_to_frame(xdp);
755 if (unlikely(!xdpf))
756 return -EOVERFLOW;
757
758
759 xdpf->dev_rx = dev_rx;
760
761 bq_enqueue(rcpu, xdpf);
762 return 0;
763}
764
765int cpu_map_generic_redirect(struct bpf_cpu_map_entry *rcpu,
766 struct sk_buff *skb)
767{
768 int ret;
769
770 __skb_pull(skb, skb->mac_len);
771 skb_set_redirected(skb, false);
772 __ptr_set_bit(0, &skb);
773
774 ret = ptr_ring_produce(rcpu->queue, skb);
775 if (ret < 0)
776 goto trace;
777
778 wake_up_process(rcpu->kthread);
779trace:
780 trace_xdp_cpumap_enqueue(rcpu->map_id, !ret, !!ret, rcpu->cpu);
781 return ret;
782}
783
784void __cpu_map_flush(void)
785{
786 struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list);
787 struct xdp_bulk_queue *bq, *tmp;
788
789 list_for_each_entry_safe(bq, tmp, flush_list, flush_node) {
790 bq_flush_to_queue(bq);
791
792
793 wake_up_process(bq->obj->kthread);
794 }
795}
796
797static int __init cpu_map_init(void)
798{
799 int cpu;
800
801 for_each_possible_cpu(cpu)
802 INIT_LIST_HEAD(&per_cpu(cpu_map_flush_list, cpu));
803 return 0;
804}
805
806subsys_initcall(cpu_map_init);
807