xref: /openbmc/linux/net/bpf/test_run.c (revision a17922de)
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 
14 static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx)
15 {
16 	u32 ret;
17 
18 	preempt_disable();
19 	rcu_read_lock();
20 	ret = BPF_PROG_RUN(prog, ctx);
21 	rcu_read_unlock();
22 	preempt_enable();
23 
24 	return ret;
25 }
26 
27 static u32 bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *time)
28 {
29 	u64 time_start, time_spent = 0;
30 	u32 ret = 0, i;
31 
32 	if (!repeat)
33 		repeat = 1;
34 	time_start = ktime_get_ns();
35 	for (i = 0; i < repeat; i++) {
36 		ret = bpf_test_run_one(prog, ctx);
37 		if (need_resched()) {
38 			if (signal_pending(current))
39 				break;
40 			time_spent += ktime_get_ns() - time_start;
41 			cond_resched();
42 			time_start = ktime_get_ns();
43 		}
44 	}
45 	time_spent += ktime_get_ns() - time_start;
46 	do_div(time_spent, repeat);
47 	*time = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;
48 
49 	return ret;
50 }
51 
52 static int bpf_test_finish(const union bpf_attr *kattr,
53 			   union bpf_attr __user *uattr, const void *data,
54 			   u32 size, u32 retval, u32 duration)
55 {
56 	void __user *data_out = u64_to_user_ptr(kattr->test.data_out);
57 	int err = -EFAULT;
58 
59 	if (data_out && copy_to_user(data_out, data, size))
60 		goto out;
61 	if (copy_to_user(&uattr->test.data_size_out, &size, sizeof(size)))
62 		goto out;
63 	if (copy_to_user(&uattr->test.retval, &retval, sizeof(retval)))
64 		goto out;
65 	if (copy_to_user(&uattr->test.duration, &duration, sizeof(duration)))
66 		goto out;
67 	err = 0;
68 out:
69 	return err;
70 }
71 
72 static void *bpf_test_init(const union bpf_attr *kattr, u32 size,
73 			   u32 headroom, u32 tailroom)
74 {
75 	void __user *data_in = u64_to_user_ptr(kattr->test.data_in);
76 	void *data;
77 
78 	if (size < ETH_HLEN || size > PAGE_SIZE - headroom - tailroom)
79 		return ERR_PTR(-EINVAL);
80 
81 	data = kzalloc(size + headroom + tailroom, GFP_USER);
82 	if (!data)
83 		return ERR_PTR(-ENOMEM);
84 
85 	if (copy_from_user(data + headroom, data_in, size)) {
86 		kfree(data);
87 		return ERR_PTR(-EFAULT);
88 	}
89 	return data;
90 }
91 
92 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
93 			  union bpf_attr __user *uattr)
94 {
95 	bool is_l2 = false, is_direct_pkt_access = false;
96 	u32 size = kattr->test.data_size_in;
97 	u32 repeat = kattr->test.repeat;
98 	u32 retval, duration;
99 	int hh_len = ETH_HLEN;
100 	struct sk_buff *skb;
101 	void *data;
102 	int ret;
103 
104 	data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
105 			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
106 	if (IS_ERR(data))
107 		return PTR_ERR(data);
108 
109 	switch (prog->type) {
110 	case BPF_PROG_TYPE_SCHED_CLS:
111 	case BPF_PROG_TYPE_SCHED_ACT:
112 		is_l2 = true;
113 		/* fall through */
114 	case BPF_PROG_TYPE_LWT_IN:
115 	case BPF_PROG_TYPE_LWT_OUT:
116 	case BPF_PROG_TYPE_LWT_XMIT:
117 		is_direct_pkt_access = true;
118 		break;
119 	default:
120 		break;
121 	}
122 
123 	skb = build_skb(data, 0);
124 	if (!skb) {
125 		kfree(data);
126 		return -ENOMEM;
127 	}
128 
129 	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
130 	__skb_put(skb, size);
131 	skb->protocol = eth_type_trans(skb, current->nsproxy->net_ns->loopback_dev);
132 	skb_reset_network_header(skb);
133 
134 	if (is_l2)
135 		__skb_push(skb, hh_len);
136 	if (is_direct_pkt_access)
137 		bpf_compute_data_pointers(skb);
138 	retval = bpf_test_run(prog, skb, repeat, &duration);
139 	if (!is_l2) {
140 		if (skb_headroom(skb) < hh_len) {
141 			int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
142 
143 			if (pskb_expand_head(skb, nhead, 0, GFP_USER)) {
144 				kfree_skb(skb);
145 				return -ENOMEM;
146 			}
147 		}
148 		memset(__skb_push(skb, hh_len), 0, hh_len);
149 	}
150 
151 	size = skb->len;
152 	/* bpf program can never convert linear skb to non-linear */
153 	if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
154 		size = skb_headlen(skb);
155 	ret = bpf_test_finish(kattr, uattr, skb->data, size, retval, duration);
156 	kfree_skb(skb);
157 	return ret;
158 }
159 
160 int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
161 			  union bpf_attr __user *uattr)
162 {
163 	u32 size = kattr->test.data_size_in;
164 	u32 repeat = kattr->test.repeat;
165 	struct netdev_rx_queue *rxqueue;
166 	struct xdp_buff xdp = {};
167 	u32 retval, duration;
168 	void *data;
169 	int ret;
170 
171 	data = bpf_test_init(kattr, size, XDP_PACKET_HEADROOM + NET_IP_ALIGN, 0);
172 	if (IS_ERR(data))
173 		return PTR_ERR(data);
174 
175 	xdp.data_hard_start = data;
176 	xdp.data = data + XDP_PACKET_HEADROOM + NET_IP_ALIGN;
177 	xdp.data_meta = xdp.data;
178 	xdp.data_end = xdp.data + size;
179 
180 	rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
181 	xdp.rxq = &rxqueue->xdp_rxq;
182 
183 	retval = bpf_test_run(prog, &xdp, repeat, &duration);
184 	if (xdp.data != data + XDP_PACKET_HEADROOM + NET_IP_ALIGN ||
185 	    xdp.data_end != xdp.data + size)
186 		size = xdp.data_end - xdp.data;
187 	ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
188 	kfree(data);
189 	return ret;
190 }
191