xref: /openbmc/linux/net/bpf/test_run.c (revision feac8c8b)
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 	struct sk_buff *skb;
100 	void *data;
101 	int ret;
102 
103 	data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
104 			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
105 	if (IS_ERR(data))
106 		return PTR_ERR(data);
107 
108 	switch (prog->type) {
109 	case BPF_PROG_TYPE_SCHED_CLS:
110 	case BPF_PROG_TYPE_SCHED_ACT:
111 		is_l2 = true;
112 		/* fall through */
113 	case BPF_PROG_TYPE_LWT_IN:
114 	case BPF_PROG_TYPE_LWT_OUT:
115 	case BPF_PROG_TYPE_LWT_XMIT:
116 		is_direct_pkt_access = true;
117 		break;
118 	default:
119 		break;
120 	}
121 
122 	skb = build_skb(data, 0);
123 	if (!skb) {
124 		kfree(data);
125 		return -ENOMEM;
126 	}
127 
128 	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
129 	__skb_put(skb, size);
130 	skb->protocol = eth_type_trans(skb, current->nsproxy->net_ns->loopback_dev);
131 	skb_reset_network_header(skb);
132 
133 	if (is_l2)
134 		__skb_push(skb, ETH_HLEN);
135 	if (is_direct_pkt_access)
136 		bpf_compute_data_pointers(skb);
137 	retval = bpf_test_run(prog, skb, repeat, &duration);
138 	if (!is_l2)
139 		__skb_push(skb, ETH_HLEN);
140 	size = skb->len;
141 	/* bpf program can never convert linear skb to non-linear */
142 	if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
143 		size = skb_headlen(skb);
144 	ret = bpf_test_finish(kattr, uattr, skb->data, size, retval, duration);
145 	kfree_skb(skb);
146 	return ret;
147 }
148 
149 int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
150 			  union bpf_attr __user *uattr)
151 {
152 	u32 size = kattr->test.data_size_in;
153 	u32 repeat = kattr->test.repeat;
154 	struct netdev_rx_queue *rxqueue;
155 	struct xdp_buff xdp = {};
156 	u32 retval, duration;
157 	void *data;
158 	int ret;
159 
160 	data = bpf_test_init(kattr, size, XDP_PACKET_HEADROOM + NET_IP_ALIGN, 0);
161 	if (IS_ERR(data))
162 		return PTR_ERR(data);
163 
164 	xdp.data_hard_start = data;
165 	xdp.data = data + XDP_PACKET_HEADROOM + NET_IP_ALIGN;
166 	xdp.data_meta = xdp.data;
167 	xdp.data_end = xdp.data + size;
168 
169 	rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
170 	xdp.rxq = &rxqueue->xdp_rxq;
171 
172 	retval = bpf_test_run(prog, &xdp, repeat, &duration);
173 	if (xdp.data != data + XDP_PACKET_HEADROOM + NET_IP_ALIGN)
174 		size = xdp.data_end - xdp.data;
175 	ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
176 	kfree(data);
177 	return ret;
178 }
179