1// SPDX-License-Identifier: GPL-2.0
2/* GPLv2, Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc. */
3#include "xdp_sample.bpf.h"
4
5#include <bpf/bpf_tracing.h>
6#include <bpf/bpf_core_read.h>
7#include <bpf/bpf_helpers.h>
8
9array_map rx_cnt SEC(".maps");
10array_map redir_err_cnt SEC(".maps");
11array_map cpumap_enqueue_cnt SEC(".maps");
12array_map cpumap_kthread_cnt SEC(".maps");
13array_map exception_cnt SEC(".maps");
14array_map devmap_xmit_cnt SEC(".maps");
15
16struct {
17 __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
18 __uint(max_entries, 32 * 32);
19 __type(key, u64);
20 __type(value, struct datarec);
21} devmap_xmit_cnt_multi SEC(".maps");
22
23const volatile int nr_cpus = 0;
24
25/* These can be set before loading so that redundant comparisons can be DCE'd by
26 * the verifier, and only actual matches are tried after loading tp_btf program.
27 * This allows sample to filter tracepoint stats based on net_device.
28 */
29const volatile int from_match[32] = {};
30const volatile int to_match[32] = {};
31
32int cpumap_map_id = 0;
33
34/* Find if b is part of set a, but if a is empty set then evaluate to true */
35#define IN_SET(a, b) \
36 ({ \
37 bool __res = !(a)[0]; \
38 for (int i = 0; i < ARRAY_SIZE(a) && (a)[i]; i++) { \
39 __res = (a)[i] == (b); \
40 if (__res) \
41 break; \
42 } \
43 __res; \
44 })
45
46static __always_inline __u32 xdp_get_err_key(int err)
47{
48 switch (err) {
49 case 0:
50 return 0;
51 case -EINVAL:
52 return 2;
53 case -ENETDOWN:
54 return 3;
55 case -EMSGSIZE:
56 return 4;
57 case -EOPNOTSUPP:
58 return 5;
59 case -ENOSPC:
60 return 6;
61 default:
62 return 1;
63 }
64}
65
66static __always_inline int xdp_redirect_collect_stat(int from, int err)
67{
68 u32 cpu = bpf_get_smp_processor_id();
69 u32 key = XDP_REDIRECT_ERROR;
70 struct datarec *rec;
71 u32 idx;
72
73 if (!IN_SET(from_match, from))
74 return 0;
75
76 key = xdp_get_err_key(err);
77
78 idx = key * nr_cpus + cpu;
79 rec = bpf_map_lookup_elem(&redir_err_cnt, &idx);
80 if (!rec)
81 return 0;
82 if (key)
83 NO_TEAR_INC(rec->dropped);
84 else
85 NO_TEAR_INC(rec->processed);
86 return 0; /* Indicate event was filtered (no further processing)*/
87 /*
88 * Returning 1 here would allow e.g. a perf-record tracepoint
89 * to see and record these events, but it doesn't work well
90 * in-practice as stopping perf-record also unload this
91 * bpf_prog. Plus, there is additional overhead of doing so.
92 */
93}
94
95SEC("tp_btf/xdp_redirect_err")
96int BPF_PROG(tp_xdp_redirect_err, const struct net_device *dev,
97 const struct bpf_prog *xdp, const void *tgt, int err,
98 const struct bpf_map *map, u32 index)
99{
100 return xdp_redirect_collect_stat(dev->ifindex, err);
101}
102
103SEC("tp_btf/xdp_redirect_map_err")
104int BPF_PROG(tp_xdp_redirect_map_err, const struct net_device *dev,
105 const struct bpf_prog *xdp, const void *tgt, int err,
106 const struct bpf_map *map, u32 index)
107{
108 return xdp_redirect_collect_stat(dev->ifindex, err);
109}
110
111SEC("tp_btf/xdp_redirect")
112int BPF_PROG(tp_xdp_redirect, const struct net_device *dev,
113 const struct bpf_prog *xdp, const void *tgt, int err,
114 const struct bpf_map *map, u32 index)
115{
116 return xdp_redirect_collect_stat(dev->ifindex, err);
117}
118
119SEC("tp_btf/xdp_redirect_map")
120int BPF_PROG(tp_xdp_redirect_map, const struct net_device *dev,
121 const struct bpf_prog *xdp, const void *tgt, int err,
122 const struct bpf_map *map, u32 index)
123{
124 return xdp_redirect_collect_stat(dev->ifindex, err);
125}
126
127SEC("tp_btf/xdp_cpumap_enqueue")
128int BPF_PROG(tp_xdp_cpumap_enqueue, int map_id, unsigned int processed,
129 unsigned int drops, int to_cpu)
130{
131 u32 cpu = bpf_get_smp_processor_id();
132 struct datarec *rec;
133 u32 idx;
134
135 if (cpumap_map_id && cpumap_map_id != map_id)
136 return 0;
137
138 idx = to_cpu * nr_cpus + cpu;
139 rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &idx);
140 if (!rec)
141 return 0;
142 NO_TEAR_ADD(rec->processed, processed);
143 NO_TEAR_ADD(rec->dropped, drops);
144 /* Record bulk events, then userspace can calc average bulk size */
145 if (processed > 0)
146 NO_TEAR_INC(rec->issue);
147 /* Inception: It's possible to detect overload situations, via
148 * this tracepoint. This can be used for creating a feedback
149 * loop to XDP, which can take appropriate actions to mitigate
150 * this overload situation.
151 */
152 return 0;
153}
154
155SEC("tp_btf/xdp_cpumap_kthread")
156int BPF_PROG(tp_xdp_cpumap_kthread, int map_id, unsigned int processed,
157 unsigned int drops, int sched, struct xdp_cpumap_stats *xdp_stats)
158{
159 struct datarec *rec;
160 u32 cpu;
161
162 if (cpumap_map_id && cpumap_map_id != map_id)
163 return 0;
164
165 cpu = bpf_get_smp_processor_id();
166 rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &cpu);
167 if (!rec)
168 return 0;
169 NO_TEAR_ADD(rec->processed, processed);
170 NO_TEAR_ADD(rec->dropped, drops);
171 NO_TEAR_ADD(rec->xdp_pass, xdp_stats->pass);
172 NO_TEAR_ADD(rec->xdp_drop, xdp_stats->drop);
173 NO_TEAR_ADD(rec->xdp_redirect, xdp_stats->redirect);
174 /* Count times kthread yielded CPU via schedule call */
175 if (sched)
176 NO_TEAR_INC(rec->issue);
177 return 0;
178}
179
180SEC("tp_btf/xdp_exception")
181int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
182 const struct bpf_prog *xdp, u32 act)
183{
184 u32 cpu = bpf_get_smp_processor_id();
185 struct datarec *rec;
186 u32 key = act, idx;
187
188 if (!IN_SET(from_match, dev->ifindex))
189 return 0;
190 if (!IN_SET(to_match, dev->ifindex))
191 return 0;
192
193 if (key > XDP_REDIRECT)
194 key = XDP_REDIRECT + 1;
195
196 idx = key * nr_cpus + cpu;
197 rec = bpf_map_lookup_elem(&exception_cnt, &idx);
198 if (!rec)
199 return 0;
200 NO_TEAR_INC(rec->dropped);
201
202 return 0;
203}
204
205SEC("tp_btf/xdp_devmap_xmit")
206int BPF_PROG(tp_xdp_devmap_xmit, const struct net_device *from_dev,
207 const struct net_device *to_dev, int sent, int drops, int err)
208{
209 struct datarec *rec;
210 int idx_in, idx_out;
211 u32 cpu;
212
213 idx_in = from_dev->ifindex;
214 idx_out = to_dev->ifindex;
215
216 if (!IN_SET(from_match, idx_in))
217 return 0;
218 if (!IN_SET(to_match, idx_out))
219 return 0;
220
221 cpu = bpf_get_smp_processor_id();
222 rec = bpf_map_lookup_elem(&devmap_xmit_cnt, &cpu);
223 if (!rec)
224 return 0;
225 NO_TEAR_ADD(rec->processed, sent);
226 NO_TEAR_ADD(rec->dropped, drops);
227 /* Record bulk events, then userspace can calc average bulk size */
228 NO_TEAR_INC(rec->info);
229 /* Record error cases, where no frame were sent */
230 /* Catch API error of drv ndo_xdp_xmit sent more than count */
231 if (err || drops < 0)
232 NO_TEAR_INC(rec->issue);
233 return 0;
234}
235
236SEC("tp_btf/xdp_devmap_xmit")
237int BPF_PROG(tp_xdp_devmap_xmit_multi, const struct net_device *from_dev,
238 const struct net_device *to_dev, int sent, int drops, int err)
239{
240 struct datarec empty = {};
241 struct datarec *rec;
242 int idx_in, idx_out;
243 u64 idx;
244
245 idx_in = from_dev->ifindex;
246 idx_out = to_dev->ifindex;
247 idx = idx_in;
248 idx = idx << 32 | idx_out;
249
250 if (!IN_SET(from_match, idx_in))
251 return 0;
252 if (!IN_SET(to_match, idx_out))
253 return 0;
254
255 bpf_map_update_elem(&devmap_xmit_cnt_multi, &idx, &empty, BPF_NOEXIST);
256 rec = bpf_map_lookup_elem(&devmap_xmit_cnt_multi, &idx);
257 if (!rec)
258 return 0;
259
260 NO_TEAR_ADD(rec->processed, sent);
261 NO_TEAR_ADD(rec->dropped, drops);
262 NO_TEAR_INC(rec->info);
263 if (err || drops < 0)
264 NO_TEAR_INC(rec->issue);
265 return 0;
266}
267

source code of linux/samples/bpf/xdp_sample.bpf.c