xref: /openbmc/linux/net/bpf/test_run.c (revision ae213c44)
1 /* Copyright (c) 2017 Facebook
2  *
3  * This program is free software; you can redistribute it and/or
4  * modify it under the terms of version 2 of the GNU General Public
5  * License as published by the Free Software Foundation.
6  */
7 #include <linux/bpf.h>
8 #include <linux/slab.h>
9 #include <linux/vmalloc.h>
10 #include <linux/etherdevice.h>
11 #include <linux/filter.h>
12 #include <linux/sched/signal.h>
13 #include <net/bpf_sk_storage.h>
14 #include <net/sock.h>
15 #include <net/tcp.h>
16 
17 #define CREATE_TRACE_POINTS
18 #include <trace/events/bpf_test_run.h>
19 
20 static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,
21 			u32 *retval, u32 *time)
22 {
23 	struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = { NULL };
24 	enum bpf_cgroup_storage_type stype;
25 	u64 time_start, time_spent = 0;
26 	int ret = 0;
27 	u32 i;
28 
29 	for_each_cgroup_storage_type(stype) {
30 		storage[stype] = bpf_cgroup_storage_alloc(prog, stype);
31 		if (IS_ERR(storage[stype])) {
32 			storage[stype] = NULL;
33 			for_each_cgroup_storage_type(stype)
34 				bpf_cgroup_storage_free(storage[stype]);
35 			return -ENOMEM;
36 		}
37 	}
38 
39 	if (!repeat)
40 		repeat = 1;
41 
42 	rcu_read_lock();
43 	preempt_disable();
44 	time_start = ktime_get_ns();
45 	for (i = 0; i < repeat; i++) {
46 		bpf_cgroup_storage_set(storage);
47 		*retval = BPF_PROG_RUN(prog, ctx);
48 
49 		if (signal_pending(current)) {
50 			ret = -EINTR;
51 			break;
52 		}
53 
54 		if (need_resched()) {
55 			time_spent += ktime_get_ns() - time_start;
56 			preempt_enable();
57 			rcu_read_unlock();
58 
59 			cond_resched();
60 
61 			rcu_read_lock();
62 			preempt_disable();
63 			time_start = ktime_get_ns();
64 		}
65 	}
66 	time_spent += ktime_get_ns() - time_start;
67 	preempt_enable();
68 	rcu_read_unlock();
69 
70 	do_div(time_spent, repeat);
71 	*time = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;
72 
73 	for_each_cgroup_storage_type(stype)
74 		bpf_cgroup_storage_free(storage[stype]);
75 
76 	return ret;
77 }
78 
79 static int bpf_test_finish(const union bpf_attr *kattr,
80 			   union bpf_attr __user *uattr, const void *data,
81 			   u32 size, u32 retval, u32 duration)
82 {
83 	void __user *data_out = u64_to_user_ptr(kattr->test.data_out);
84 	int err = -EFAULT;
85 	u32 copy_size = size;
86 
87 	/* Clamp copy if the user has provided a size hint, but copy the full
88 	 * buffer if not to retain old behaviour.
89 	 */
90 	if (kattr->test.data_size_out &&
91 	    copy_size > kattr->test.data_size_out) {
92 		copy_size = kattr->test.data_size_out;
93 		err = -ENOSPC;
94 	}
95 
96 	if (data_out && copy_to_user(data_out, data, copy_size))
97 		goto out;
98 	if (copy_to_user(&uattr->test.data_size_out, &size, sizeof(size)))
99 		goto out;
100 	if (copy_to_user(&uattr->test.retval, &retval, sizeof(retval)))
101 		goto out;
102 	if (copy_to_user(&uattr->test.duration, &duration, sizeof(duration)))
103 		goto out;
104 	if (err != -ENOSPC)
105 		err = 0;
106 out:
107 	trace_bpf_test_finish(&err);
108 	return err;
109 }
110 
111 static void *bpf_test_init(const union bpf_attr *kattr, u32 size,
112 			   u32 headroom, u32 tailroom)
113 {
114 	void __user *data_in = u64_to_user_ptr(kattr->test.data_in);
115 	void *data;
116 
117 	if (size < ETH_HLEN || size > PAGE_SIZE - headroom - tailroom)
118 		return ERR_PTR(-EINVAL);
119 
120 	data = kzalloc(size + headroom + tailroom, GFP_USER);
121 	if (!data)
122 		return ERR_PTR(-ENOMEM);
123 
124 	if (copy_from_user(data + headroom, data_in, size)) {
125 		kfree(data);
126 		return ERR_PTR(-EFAULT);
127 	}
128 	return data;
129 }
130 
131 static void *bpf_ctx_init(const union bpf_attr *kattr, u32 max_size)
132 {
133 	void __user *data_in = u64_to_user_ptr(kattr->test.ctx_in);
134 	void __user *data_out = u64_to_user_ptr(kattr->test.ctx_out);
135 	u32 size = kattr->test.ctx_size_in;
136 	void *data;
137 	int err;
138 
139 	if (!data_in && !data_out)
140 		return NULL;
141 
142 	data = kzalloc(max_size, GFP_USER);
143 	if (!data)
144 		return ERR_PTR(-ENOMEM);
145 
146 	if (data_in) {
147 		err = bpf_check_uarg_tail_zero(data_in, max_size, size);
148 		if (err) {
149 			kfree(data);
150 			return ERR_PTR(err);
151 		}
152 
153 		size = min_t(u32, max_size, size);
154 		if (copy_from_user(data, data_in, size)) {
155 			kfree(data);
156 			return ERR_PTR(-EFAULT);
157 		}
158 	}
159 	return data;
160 }
161 
162 static int bpf_ctx_finish(const union bpf_attr *kattr,
163 			  union bpf_attr __user *uattr, const void *data,
164 			  u32 size)
165 {
166 	void __user *data_out = u64_to_user_ptr(kattr->test.ctx_out);
167 	int err = -EFAULT;
168 	u32 copy_size = size;
169 
170 	if (!data || !data_out)
171 		return 0;
172 
173 	if (copy_size > kattr->test.ctx_size_out) {
174 		copy_size = kattr->test.ctx_size_out;
175 		err = -ENOSPC;
176 	}
177 
178 	if (copy_to_user(data_out, data, copy_size))
179 		goto out;
180 	if (copy_to_user(&uattr->test.ctx_size_out, &size, sizeof(size)))
181 		goto out;
182 	if (err != -ENOSPC)
183 		err = 0;
184 out:
185 	return err;
186 }
187 
188 /**
189  * range_is_zero - test whether buffer is initialized
190  * @buf: buffer to check
191  * @from: check from this position
192  * @to: check up until (excluding) this position
193  *
194  * This function returns true if the there is a non-zero byte
195  * in the buf in the range [from,to).
196  */
197 static inline bool range_is_zero(void *buf, size_t from, size_t to)
198 {
199 	return !memchr_inv((u8 *)buf + from, 0, to - from);
200 }
201 
202 static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
203 {
204 	struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
205 
206 	if (!__skb)
207 		return 0;
208 
209 	/* make sure the fields we don't use are zeroed */
210 	if (!range_is_zero(__skb, 0, offsetof(struct __sk_buff, priority)))
211 		return -EINVAL;
212 
213 	/* priority is allowed */
214 
215 	if (!range_is_zero(__skb, offsetof(struct __sk_buff, priority) +
216 			   FIELD_SIZEOF(struct __sk_buff, priority),
217 			   offsetof(struct __sk_buff, cb)))
218 		return -EINVAL;
219 
220 	/* cb is allowed */
221 
222 	if (!range_is_zero(__skb, offsetof(struct __sk_buff, cb) +
223 			   FIELD_SIZEOF(struct __sk_buff, cb),
224 			   sizeof(struct __sk_buff)))
225 		return -EINVAL;
226 
227 	skb->priority = __skb->priority;
228 	memcpy(&cb->data, __skb->cb, QDISC_CB_PRIV_LEN);
229 
230 	return 0;
231 }
232 
233 static void convert_skb_to___skb(struct sk_buff *skb, struct __sk_buff *__skb)
234 {
235 	struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
236 
237 	if (!__skb)
238 		return;
239 
240 	__skb->priority = skb->priority;
241 	memcpy(__skb->cb, &cb->data, QDISC_CB_PRIV_LEN);
242 }
243 
244 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
245 			  union bpf_attr __user *uattr)
246 {
247 	bool is_l2 = false, is_direct_pkt_access = false;
248 	u32 size = kattr->test.data_size_in;
249 	u32 repeat = kattr->test.repeat;
250 	struct __sk_buff *ctx = NULL;
251 	u32 retval, duration;
252 	int hh_len = ETH_HLEN;
253 	struct sk_buff *skb;
254 	struct sock *sk;
255 	void *data;
256 	int ret;
257 
258 	data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
259 			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
260 	if (IS_ERR(data))
261 		return PTR_ERR(data);
262 
263 	ctx = bpf_ctx_init(kattr, sizeof(struct __sk_buff));
264 	if (IS_ERR(ctx)) {
265 		kfree(data);
266 		return PTR_ERR(ctx);
267 	}
268 
269 	switch (prog->type) {
270 	case BPF_PROG_TYPE_SCHED_CLS:
271 	case BPF_PROG_TYPE_SCHED_ACT:
272 		is_l2 = true;
273 		/* fall through */
274 	case BPF_PROG_TYPE_LWT_IN:
275 	case BPF_PROG_TYPE_LWT_OUT:
276 	case BPF_PROG_TYPE_LWT_XMIT:
277 		is_direct_pkt_access = true;
278 		break;
279 	default:
280 		break;
281 	}
282 
283 	sk = kzalloc(sizeof(struct sock), GFP_USER);
284 	if (!sk) {
285 		kfree(data);
286 		kfree(ctx);
287 		return -ENOMEM;
288 	}
289 	sock_net_set(sk, current->nsproxy->net_ns);
290 	sock_init_data(NULL, sk);
291 
292 	skb = build_skb(data, 0);
293 	if (!skb) {
294 		kfree(data);
295 		kfree(ctx);
296 		kfree(sk);
297 		return -ENOMEM;
298 	}
299 	skb->sk = sk;
300 
301 	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
302 	__skb_put(skb, size);
303 	skb->protocol = eth_type_trans(skb, current->nsproxy->net_ns->loopback_dev);
304 	skb_reset_network_header(skb);
305 
306 	if (is_l2)
307 		__skb_push(skb, hh_len);
308 	if (is_direct_pkt_access)
309 		bpf_compute_data_pointers(skb);
310 	ret = convert___skb_to_skb(skb, ctx);
311 	if (ret)
312 		goto out;
313 	ret = bpf_test_run(prog, skb, repeat, &retval, &duration);
314 	if (ret)
315 		goto out;
316 	if (!is_l2) {
317 		if (skb_headroom(skb) < hh_len) {
318 			int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
319 
320 			if (pskb_expand_head(skb, nhead, 0, GFP_USER)) {
321 				ret = -ENOMEM;
322 				goto out;
323 			}
324 		}
325 		memset(__skb_push(skb, hh_len), 0, hh_len);
326 	}
327 	convert_skb_to___skb(skb, ctx);
328 
329 	size = skb->len;
330 	/* bpf program can never convert linear skb to non-linear */
331 	if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
332 		size = skb_headlen(skb);
333 	ret = bpf_test_finish(kattr, uattr, skb->data, size, retval, duration);
334 	if (!ret)
335 		ret = bpf_ctx_finish(kattr, uattr, ctx,
336 				     sizeof(struct __sk_buff));
337 out:
338 	kfree_skb(skb);
339 	bpf_sk_storage_free(sk);
340 	kfree(sk);
341 	kfree(ctx);
342 	return ret;
343 }
344 
345 int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
346 			  union bpf_attr __user *uattr)
347 {
348 	u32 size = kattr->test.data_size_in;
349 	u32 repeat = kattr->test.repeat;
350 	struct netdev_rx_queue *rxqueue;
351 	struct xdp_buff xdp = {};
352 	u32 retval, duration;
353 	void *data;
354 	int ret;
355 
356 	if (kattr->test.ctx_in || kattr->test.ctx_out)
357 		return -EINVAL;
358 
359 	data = bpf_test_init(kattr, size, XDP_PACKET_HEADROOM + NET_IP_ALIGN, 0);
360 	if (IS_ERR(data))
361 		return PTR_ERR(data);
362 
363 	xdp.data_hard_start = data;
364 	xdp.data = data + XDP_PACKET_HEADROOM + NET_IP_ALIGN;
365 	xdp.data_meta = xdp.data;
366 	xdp.data_end = xdp.data + size;
367 
368 	rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
369 	xdp.rxq = &rxqueue->xdp_rxq;
370 
371 	ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration);
372 	if (ret)
373 		goto out;
374 	if (xdp.data != data + XDP_PACKET_HEADROOM + NET_IP_ALIGN ||
375 	    xdp.data_end != xdp.data + size)
376 		size = xdp.data_end - xdp.data;
377 	ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
378 out:
379 	kfree(data);
380 	return ret;
381 }
382 
383 int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
384 				     const union bpf_attr *kattr,
385 				     union bpf_attr __user *uattr)
386 {
387 	u32 size = kattr->test.data_size_in;
388 	struct bpf_flow_dissector ctx = {};
389 	u32 repeat = kattr->test.repeat;
390 	struct bpf_flow_keys flow_keys;
391 	u64 time_start, time_spent = 0;
392 	const struct ethhdr *eth;
393 	u32 retval, duration;
394 	void *data;
395 	int ret;
396 	u32 i;
397 
398 	if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)
399 		return -EINVAL;
400 
401 	if (kattr->test.ctx_in || kattr->test.ctx_out)
402 		return -EINVAL;
403 
404 	if (size < ETH_HLEN)
405 		return -EINVAL;
406 
407 	data = bpf_test_init(kattr, size, 0, 0);
408 	if (IS_ERR(data))
409 		return PTR_ERR(data);
410 
411 	eth = (struct ethhdr *)data;
412 
413 	if (!repeat)
414 		repeat = 1;
415 
416 	ctx.flow_keys = &flow_keys;
417 	ctx.data = data;
418 	ctx.data_end = (__u8 *)data + size;
419 
420 	rcu_read_lock();
421 	preempt_disable();
422 	time_start = ktime_get_ns();
423 	for (i = 0; i < repeat; i++) {
424 		retval = bpf_flow_dissect(prog, &ctx, eth->h_proto, ETH_HLEN,
425 					  size);
426 
427 		if (signal_pending(current)) {
428 			preempt_enable();
429 			rcu_read_unlock();
430 
431 			ret = -EINTR;
432 			goto out;
433 		}
434 
435 		if (need_resched()) {
436 			time_spent += ktime_get_ns() - time_start;
437 			preempt_enable();
438 			rcu_read_unlock();
439 
440 			cond_resched();
441 
442 			rcu_read_lock();
443 			preempt_disable();
444 			time_start = ktime_get_ns();
445 		}
446 	}
447 	time_spent += ktime_get_ns() - time_start;
448 	preempt_enable();
449 	rcu_read_unlock();
450 
451 	do_div(time_spent, repeat);
452 	duration = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;
453 
454 	ret = bpf_test_finish(kattr, uattr, &flow_keys, sizeof(flow_keys),
455 			      retval, duration);
456 
457 out:
458 	kfree(data);
459 	return ret;
460 }
461