summaryrefslogtreecommitdiff
path: root/samples/bpf/xdp_monitor_kern.c
blob: 211db8ded0de36e8514d3b91af0587cba78d89c2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
/* SPDX-License-Identifier: GPL-2.0
 *  Copyright(c) 2017-2018 Jesper Dangaard Brouer, Red Hat Inc.
 *
 * XDP monitor tool, based on tracepoints
 */
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"

struct bpf_map_def SEC("maps") redirect_err_cnt = {
	.type = BPF_MAP_TYPE_PERCPU_ARRAY,
	.key_size = sizeof(u32),
	.value_size = sizeof(u64),
	.max_entries = 2,
	/* TODO: have entries for all possible errno's */
};

#define XDP_UNKNOWN	XDP_REDIRECT + 1
struct bpf_map_def SEC("maps") exception_cnt = {
	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
	.key_size	= sizeof(u32),
	.value_size	= sizeof(u64),
	.max_entries	= XDP_UNKNOWN + 1,
};

/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
 * Code in:                kernel/include/trace/events/xdp.h
 */
struct xdp_redirect_ctx {
	u64 __pad;		// First 8 bytes are not accessible by bpf code
	int prog_id;		//	offset:8;  size:4; signed:1;
	u32 act;		//	offset:12  size:4; signed:0;
	int ifindex;		//	offset:16  size:4; signed:1;
	int err;		//	offset:20  size:4; signed:1;
	int to_ifindex;		//	offset:24  size:4; signed:1;
	u32 map_id;		//	offset:28  size:4; signed:0;
	int map_index;		//	offset:32  size:4; signed:1;
};				//	offset:36

enum {
	XDP_REDIRECT_SUCCESS = 0,
	XDP_REDIRECT_ERROR = 1
};

static __always_inline
int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx)
{
	u32 key = XDP_REDIRECT_ERROR;
	int err = ctx->err;
	u64 *cnt;

	if (!err)
		key = XDP_REDIRECT_SUCCESS;

	cnt  = bpf_map_lookup_elem(&redirect_err_cnt, &key);
	if (!cnt)
		return 1;
	*cnt += 1;

	return 0; /* Indicate event was filtered (no further processing)*/
	/*
	 * Returning 1 here would allow e.g. a perf-record tracepoint
	 * to see and record these events, but it doesn't work well
	 * in-practice as stopping perf-record also unload this
	 * bpf_prog.  Plus, there is additional overhead of doing so.
	 */
}

SEC("tracepoint/xdp/xdp_redirect_err")
int trace_xdp_redirect_err(struct xdp_redirect_ctx *ctx)
{
	return xdp_redirect_collect_stat(ctx);
}


SEC("tracepoint/xdp/xdp_redirect_map_err")
int trace_xdp_redirect_map_err(struct xdp_redirect_ctx *ctx)
{
	return xdp_redirect_collect_stat(ctx);
}

/* Likely unloaded when prog starts */
SEC("tracepoint/xdp/xdp_redirect")
int trace_xdp_redirect(struct xdp_redirect_ctx *ctx)
{
	return xdp_redirect_collect_stat(ctx);
}

/* Likely unloaded when prog starts */
SEC("tracepoint/xdp/xdp_redirect_map")
int trace_xdp_redirect_map(struct xdp_redirect_ctx *ctx)
{
	return xdp_redirect_collect_stat(ctx);
}

/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_exception/format
 * Code in:                kernel/include/trace/events/xdp.h
 */
struct xdp_exception_ctx {
	u64 __pad;	// First 8 bytes are not accessible by bpf code
	int prog_id;	//	offset:8;  size:4; signed:1;
	u32 act;	//	offset:12; size:4; signed:0;
	int ifindex;	//	offset:16; size:4; signed:1;
};

SEC("tracepoint/xdp/xdp_exception")
int trace_xdp_exception(struct xdp_exception_ctx *ctx)
{
	u64 *cnt;
	u32 key;

	key = ctx->act;
	if (key > XDP_REDIRECT)
		key = XDP_UNKNOWN;

	cnt = bpf_map_lookup_elem(&exception_cnt, &key);
	if (!cnt)
		return 1;
	*cnt += 1;

	return 0;
}

/* Common stats data record shared with _user.c */
struct datarec {
	u64 processed;
	u64 dropped;
	u64 info;
};
#define MAX_CPUS 64

struct bpf_map_def SEC("maps") cpumap_enqueue_cnt = {
	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
	.key_size	= sizeof(u32),
	.value_size	= sizeof(struct datarec),
	.max_entries	= MAX_CPUS,
};

struct bpf_map_def SEC("maps") cpumap_kthread_cnt = {
	.type		= BPF_MAP_TYPE_PERCPU_ARRAY,
	.key_size	= sizeof(u32),
	.value_size	= sizeof(struct datarec),
	.max_entries	= 1,
};

/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_enqueue/format
 * Code in:         kernel/include/trace/events/xdp.h
 */
struct cpumap_enqueue_ctx {
	u64 __pad;		// First 8 bytes are not accessible by bpf code
	int map_id;		//	offset:8;  size:4; signed:1;
	u32 act;		//	offset:12; size:4; signed:0;
	int cpu;		//	offset:16; size:4; signed:1;
	unsigned int drops;	//	offset:20; size:4; signed:0;
	unsigned int processed;	//	offset:24; size:4; signed:0;
	int to_cpu;		//	offset:28; size:4; signed:1;
};

SEC("tracepoint/xdp/xdp_cpumap_enqueue")
int trace_xdp_cpumap_enqueue(struct cpumap_enqueue_ctx *ctx)
{
	u32 to_cpu = ctx->to_cpu;
	struct datarec *rec;

	if (to_cpu >= MAX_CPUS)
		return 1;

	rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &to_cpu);
	if (!rec)
		return 0;
	rec->processed += ctx->processed;
	rec->dropped   += ctx->drops;

	/* Record bulk events, then userspace can calc average bulk size */
	if (ctx->processed > 0)
		rec->info += 1;

	return 0;
}

/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_kthread/format
 * Code in:         kernel/include/trace/events/xdp.h
 */
struct cpumap_kthread_ctx {
	u64 __pad;		// First 8 bytes are not accessible by bpf code
	int map_id;		//	offset:8;  size:4; signed:1;
	u32 act;		//	offset:12; size:4; signed:0;
	int cpu;		//	offset:16; size:4; signed:1;
	unsigned int drops;	//	offset:20; size:4; signed:0;
	unsigned int processed;	//	offset:24; size:4; signed:0;
	int sched;		//	offset:28; size:4; signed:1;
};

SEC("tracepoint/xdp/xdp_cpumap_kthread")
int trace_xdp_cpumap_kthread(struct cpumap_kthread_ctx *ctx)
{
	struct datarec *rec;
	u32 key = 0;

	rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &key);
	if (!rec)
		return 0;
	rec->processed += ctx->processed;
	rec->dropped   += ctx->drops;

	/* Count times kthread yielded CPU via schedule call */
	if (ctx->sched)
		rec->info++;

	return 0;
}