tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/* SPDX-License-Identifier: GPL-2.0
2 * Copyright(c) 2017-2018 Jesper Dangaard Brouer, Red Hat Inc.
3 *
4 * XDP monitor tool, based on tracepoints
5 */
6#include <uapi/linux/bpf.h>
7#include "bpf_helpers.h"
8
9struct bpf_map_def SEC("maps") redirect_err_cnt = {
10 .type = BPF_MAP_TYPE_PERCPU_ARRAY,
11 .key_size = sizeof(u32),
12 .value_size = sizeof(u64),
13 .max_entries = 2,
14 /* TODO: have entries for all possible errno's */
15};
16
17#define XDP_UNKNOWN XDP_REDIRECT + 1
18struct bpf_map_def SEC("maps") exception_cnt = {
19 .type = BPF_MAP_TYPE_PERCPU_ARRAY,
20 .key_size = sizeof(u32),
21 .value_size = sizeof(u64),
22 .max_entries = XDP_UNKNOWN + 1,
23};
24
25/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
26 * Code in: kernel/include/trace/events/xdp.h
27 */
28struct xdp_redirect_ctx {
29 u64 __pad; // First 8 bytes are not accessible by bpf code
30 int prog_id; // offset:8; size:4; signed:1;
31 u32 act; // offset:12 size:4; signed:0;
32 int ifindex; // offset:16 size:4; signed:1;
33 int err; // offset:20 size:4; signed:1;
34 int to_ifindex; // offset:24 size:4; signed:1;
35 u32 map_id; // offset:28 size:4; signed:0;
36 int map_index; // offset:32 size:4; signed:1;
37}; // offset:36
38
39enum {
40 XDP_REDIRECT_SUCCESS = 0,
41 XDP_REDIRECT_ERROR = 1
42};
43
44static __always_inline
45int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx)
46{
47 u32 key = XDP_REDIRECT_ERROR;
48 int err = ctx->err;
49 u64 *cnt;
50
51 if (!err)
52 key = XDP_REDIRECT_SUCCESS;
53
54 cnt = bpf_map_lookup_elem(&redirect_err_cnt, &key);
55 if (!cnt)
56 return 1;
57 *cnt += 1;
58
59 return 0; /* Indicate event was filtered (no further processing)*/
60 /*
61 * Returning 1 here would allow e.g. a perf-record tracepoint
62 * to see and record these events, but it doesn't work well
63 * in-practice as stopping perf-record also unload this
64 * bpf_prog. Plus, there is additional overhead of doing so.
65 */
66}
67
68SEC("tracepoint/xdp/xdp_redirect_err")
69int trace_xdp_redirect_err(struct xdp_redirect_ctx *ctx)
70{
71 return xdp_redirect_collect_stat(ctx);
72}
73
74
75SEC("tracepoint/xdp/xdp_redirect_map_err")
76int trace_xdp_redirect_map_err(struct xdp_redirect_ctx *ctx)
77{
78 return xdp_redirect_collect_stat(ctx);
79}
80
81/* Likely unloaded when prog starts */
82SEC("tracepoint/xdp/xdp_redirect")
83int trace_xdp_redirect(struct xdp_redirect_ctx *ctx)
84{
85 return xdp_redirect_collect_stat(ctx);
86}
87
88/* Likely unloaded when prog starts */
89SEC("tracepoint/xdp/xdp_redirect_map")
90int trace_xdp_redirect_map(struct xdp_redirect_ctx *ctx)
91{
92 return xdp_redirect_collect_stat(ctx);
93}
94
95/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_exception/format
96 * Code in: kernel/include/trace/events/xdp.h
97 */
98struct xdp_exception_ctx {
99 u64 __pad; // First 8 bytes are not accessible by bpf code
100 int prog_id; // offset:8; size:4; signed:1;
101 u32 act; // offset:12; size:4; signed:0;
102 int ifindex; // offset:16; size:4; signed:1;
103};
104
105SEC("tracepoint/xdp/xdp_exception")
106int trace_xdp_exception(struct xdp_exception_ctx *ctx)
107{
108 u64 *cnt;
109 u32 key;
110
111 key = ctx->act;
112 if (key > XDP_REDIRECT)
113 key = XDP_UNKNOWN;
114
115 cnt = bpf_map_lookup_elem(&exception_cnt, &key);
116 if (!cnt)
117 return 1;
118 *cnt += 1;
119
120 return 0;
121}
122
123/* Common stats data record shared with _user.c */
124struct datarec {
125 u64 processed;
126 u64 dropped;
127 u64 info;
128 u64 err;
129};
130#define MAX_CPUS 64
131
132struct bpf_map_def SEC("maps") cpumap_enqueue_cnt = {
133 .type = BPF_MAP_TYPE_PERCPU_ARRAY,
134 .key_size = sizeof(u32),
135 .value_size = sizeof(struct datarec),
136 .max_entries = MAX_CPUS,
137};
138
139struct bpf_map_def SEC("maps") cpumap_kthread_cnt = {
140 .type = BPF_MAP_TYPE_PERCPU_ARRAY,
141 .key_size = sizeof(u32),
142 .value_size = sizeof(struct datarec),
143 .max_entries = 1,
144};
145
146/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_enqueue/format
147 * Code in: kernel/include/trace/events/xdp.h
148 */
149struct cpumap_enqueue_ctx {
150 u64 __pad; // First 8 bytes are not accessible by bpf code
151 int map_id; // offset:8; size:4; signed:1;
152 u32 act; // offset:12; size:4; signed:0;
153 int cpu; // offset:16; size:4; signed:1;
154 unsigned int drops; // offset:20; size:4; signed:0;
155 unsigned int processed; // offset:24; size:4; signed:0;
156 int to_cpu; // offset:28; size:4; signed:1;
157};
158
159SEC("tracepoint/xdp/xdp_cpumap_enqueue")
160int trace_xdp_cpumap_enqueue(struct cpumap_enqueue_ctx *ctx)
161{
162 u32 to_cpu = ctx->to_cpu;
163 struct datarec *rec;
164
165 if (to_cpu >= MAX_CPUS)
166 return 1;
167
168 rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &to_cpu);
169 if (!rec)
170 return 0;
171 rec->processed += ctx->processed;
172 rec->dropped += ctx->drops;
173
174 /* Record bulk events, then userspace can calc average bulk size */
175 if (ctx->processed > 0)
176 rec->info += 1;
177
178 return 0;
179}
180
181/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_kthread/format
182 * Code in: kernel/include/trace/events/xdp.h
183 */
184struct cpumap_kthread_ctx {
185 u64 __pad; // First 8 bytes are not accessible by bpf code
186 int map_id; // offset:8; size:4; signed:1;
187 u32 act; // offset:12; size:4; signed:0;
188 int cpu; // offset:16; size:4; signed:1;
189 unsigned int drops; // offset:20; size:4; signed:0;
190 unsigned int processed; // offset:24; size:4; signed:0;
191 int sched; // offset:28; size:4; signed:1;
192};
193
194SEC("tracepoint/xdp/xdp_cpumap_kthread")
195int trace_xdp_cpumap_kthread(struct cpumap_kthread_ctx *ctx)
196{
197 struct datarec *rec;
198 u32 key = 0;
199
200 rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &key);
201 if (!rec)
202 return 0;
203 rec->processed += ctx->processed;
204 rec->dropped += ctx->drops;
205
206 /* Count times kthread yielded CPU via schedule call */
207 if (ctx->sched)
208 rec->info++;
209
210 return 0;
211}
212
213struct bpf_map_def SEC("maps") devmap_xmit_cnt = {
214 .type = BPF_MAP_TYPE_PERCPU_ARRAY,
215 .key_size = sizeof(u32),
216 .value_size = sizeof(struct datarec),
217 .max_entries = 1,
218};
219
220/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_devmap_xmit/format
221 * Code in: kernel/include/trace/events/xdp.h
222 */
223struct devmap_xmit_ctx {
224 u64 __pad; // First 8 bytes are not accessible by bpf code
225 int map_id; // offset:8; size:4; signed:1;
226 u32 act; // offset:12; size:4; signed:0;
227 u32 map_index; // offset:16; size:4; signed:0;
228 int drops; // offset:20; size:4; signed:1;
229 int sent; // offset:24; size:4; signed:1;
230 int from_ifindex; // offset:28; size:4; signed:1;
231 int to_ifindex; // offset:32; size:4; signed:1;
232 int err; // offset:36; size:4; signed:1;
233};
234
235SEC("tracepoint/xdp/xdp_devmap_xmit")
236int trace_xdp_devmap_xmit(struct devmap_xmit_ctx *ctx)
237{
238 struct datarec *rec;
239 u32 key = 0;
240
241 rec = bpf_map_lookup_elem(&devmap_xmit_cnt, &key);
242 if (!rec)
243 return 0;
244 rec->processed += ctx->sent;
245 rec->dropped += ctx->drops;
246
247 /* Record bulk events, then userspace can calc average bulk size */
248 rec->info += 1;
249
250 /* Record error cases, where no frame were sent */
251 if (ctx->err)
252 rec->err++;
253
254 /* Catch API error of drv ndo_xdp_xmit sent more than count */
255 if (ctx->drops < 0)
256 rec->err++;
257
258 return 1;
259}