1
2#include <stdio.h>
3#include <stdlib.h>
4#include <string.h>
5#include <linux/perf_event.h>
6#include <linux/bpf.h>
7#include <net/if.h>
8#include <errno.h>
9#include <assert.h>
10#include <sys/sysinfo.h>
11#include <sys/ioctl.h>
12#include <signal.h>
13#include <bpf/libbpf.h>
14#include <bpf/bpf.h>
15#include <libgen.h>
16#include <linux/if_link.h>
17
18#include "perf-sys.h"
19
20static int if_idx;
21static char *if_name;
22static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
23static __u32 prog_id;
24static struct perf_buffer *pb = NULL;
25
26static int do_attach(int idx, int fd, const char *name)
27{
28 struct bpf_prog_info info = {};
29 __u32 info_len = sizeof(info);
30 int err;
31
32 err = bpf_xdp_attach(idx, fd, xdp_flags, NULL);
33 if (err < 0) {
34 printf("ERROR: failed to attach program to %s\n", name);
35 return err;
36 }
37
38 err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
39 if (err) {
40 printf("can't get prog info - %s\n", strerror(errno));
41 return err;
42 }
43 prog_id = info.id;
44
45 return err;
46}
47
48static int do_detach(int idx, const char *name)
49{
50 __u32 curr_prog_id = 0;
51 int err = 0;
52
53 err = bpf_xdp_query_id(idx, xdp_flags, &curr_prog_id);
54 if (err) {
55 printf("bpf_xdp_query_id failed\n");
56 return err;
57 }
58 if (prog_id == curr_prog_id) {
59 err = bpf_xdp_detach(idx, xdp_flags, NULL);
60 if (err < 0)
61 printf("ERROR: failed to detach prog from %s\n", name);
62 } else if (!curr_prog_id) {
63 printf("couldn't find a prog id on a %s\n", name);
64 } else {
65 printf("program on interface changed, not removing\n");
66 }
67
68 return err;
69}
70
71#define SAMPLE_SIZE 64
72
73static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
74{
75 struct {
76 __u16 cookie;
77 __u16 pkt_len;
78 __u8 pkt_data[SAMPLE_SIZE];
79 } __packed *e = data;
80 int i;
81
82 if (e->cookie != 0xdead) {
83 printf("BUG cookie %x sized %d\n", e->cookie, size);
84 return;
85 }
86
87 printf("Pkt len: %-5d bytes. Ethernet hdr: ", e->pkt_len);
88 for (i = 0; i < 14 && i < e->pkt_len; i++)
89 printf("%02x ", e->pkt_data[i]);
90 printf("\n");
91}
92
93static void sig_handler(int signo)
94{
95 do_detach(if_idx, if_name);
96 perf_buffer__free(pb);
97 exit(0);
98}
99
100static void usage(const char *prog)
101{
102 fprintf(stderr,
103 "%s: %s [OPTS] <ifname|ifindex>\n\n"
104 "OPTS:\n"
105 " -F force loading prog\n"
106 " -S use skb-mode\n",
107 __func__, prog);
108}
109
110int main(int argc, char **argv)
111{
112 const char *optstr = "FS";
113 int prog_fd, map_fd, opt;
114 struct bpf_program *prog;
115 struct bpf_object *obj;
116 struct bpf_map *map;
117 char filename[256];
118 int ret, err;
119
120 while ((opt = getopt(argc, argv, optstr)) != -1) {
121 switch (opt) {
122 case 'F':
123 xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
124 break;
125 case 'S':
126 xdp_flags |= XDP_FLAGS_SKB_MODE;
127 break;
128 default:
129 usage(basename(argv[0]));
130 return 1;
131 }
132 }
133
134 if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
135 xdp_flags |= XDP_FLAGS_DRV_MODE;
136
137 if (optind == argc) {
138 usage(basename(argv[0]));
139 return 1;
140 }
141
142 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
143
144 obj = bpf_object__open_file(filename, NULL);
145 if (libbpf_get_error(obj))
146 return 1;
147
148 prog = bpf_object__next_program(obj, NULL);
149 bpf_program__set_type(prog, BPF_PROG_TYPE_XDP);
150
151 err = bpf_object__load(obj);
152 if (err)
153 return 1;
154
155 prog_fd = bpf_program__fd(prog);
156
157 map = bpf_object__next_map(obj, NULL);
158 if (!map) {
159 printf("finding a map in obj file failed\n");
160 return 1;
161 }
162 map_fd = bpf_map__fd(map);
163
164 if_idx = if_nametoindex(argv[optind]);
165 if (!if_idx)
166 if_idx = strtoul(argv[optind], NULL, 0);
167
168 if (!if_idx) {
169 fprintf(stderr, "Invalid ifname\n");
170 return 1;
171 }
172 if_name = argv[optind];
173 err = do_attach(if_idx, prog_fd, if_name);
174 if (err)
175 return err;
176
177 if (signal(SIGINT, sig_handler) ||
178 signal(SIGHUP, sig_handler) ||
179 signal(SIGTERM, sig_handler)) {
180 perror("signal");
181 return 1;
182 }
183
184 pb = perf_buffer__new(map_fd, 8, print_bpf_output, NULL, NULL, NULL);
185 err = libbpf_get_error(pb);
186 if (err) {
187 perror("perf_buffer setup failed");
188 return 1;
189 }
190
191 while ((ret = perf_buffer__poll(pb, 1000)) >= 0) {
192 }
193
194 kill(0, SIGINT);
195 return ret;
196}
197
