1// SPDX-License-Identifier: GPL-2.0
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 <sys/resource.h>
16#include <libgen.h>
17#include <linux/if_link.h>
18
19#include "perf-sys.h"
20
21static int if_idx;
22static char *if_name;
23static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
24static __u32 prog_id;
25static struct perf_buffer *pb = NULL;
26
27static int do_attach(int idx, int fd, const char *name)
28{
29	struct bpf_prog_info info = {};
30	__u32 info_len = sizeof(info);
31	int err;
32
33	err = bpf_set_link_xdp_fd(idx, fd, xdp_flags);
34	if (err < 0) {
35		printf("ERROR: failed to attach program to %s\n", name);
36		return err;
37	}
38
39	err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
40	if (err) {
41		printf("can't get prog info - %s\n", strerror(errno));
42		return err;
43	}
44	prog_id = info.id;
45
46	return err;
47}
48
49static int do_detach(int idx, const char *name)
50{
51	__u32 curr_prog_id = 0;
52	int err = 0;
53
54	err = bpf_get_link_xdp_id(idx, &curr_prog_id, xdp_flags);
55	if (err) {
56		printf("bpf_get_link_xdp_id failed\n");
57		return err;
58	}
59	if (prog_id == curr_prog_id) {
60		err = bpf_set_link_xdp_fd(idx, -1, xdp_flags);
61		if (err < 0)
62			printf("ERROR: failed to detach prog from %s\n", name);
63	} else if (!curr_prog_id) {
64		printf("couldn't find a prog id on a %s\n", name);
65	} else {
66		printf("program on interface changed, not removing\n");
67	}
68
69	return err;
70}
71
72#define SAMPLE_SIZE 64
73
74static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
75{
76	struct {
77		__u16 cookie;
78		__u16 pkt_len;
79		__u8  pkt_data[SAMPLE_SIZE];
80	} __packed *e = data;
81	int i;
82
83	if (e->cookie != 0xdead) {
84		printf("BUG cookie %x sized %d\n", e->cookie, size);
85		return;
86	}
87
88	printf("Pkt len: %-5d bytes. Ethernet hdr: ", e->pkt_len);
89	for (i = 0; i < 14 && i < e->pkt_len; i++)
90		printf("%02x ", e->pkt_data[i]);
91	printf("\n");
92}
93
94static void sig_handler(int signo)
95{
96	do_detach(if_idx, if_name);
97	perf_buffer__free(pb);
98	exit(0);
99}
100
101static void usage(const char *prog)
102{
103	fprintf(stderr,
104		"%s: %s [OPTS] <ifname|ifindex>\n\n"
105		"OPTS:\n"
106		"    -F    force loading prog\n",
107		__func__, prog);
108}
109
110int main(int argc, char **argv)
111{
112	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
113	struct bpf_prog_load_attr prog_load_attr = {
114		.prog_type	= BPF_PROG_TYPE_XDP,
115	};
116	struct perf_buffer_opts pb_opts = {};
117	const char *optstr = "FS";
118	int prog_fd, map_fd, opt;
119	struct bpf_object *obj;
120	struct bpf_map *map;
121	char filename[256];
122	int ret, err;
123
124	while ((opt = getopt(argc, argv, optstr)) != -1) {
125		switch (opt) {
126		case 'F':
127			xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
128			break;
129		case 'S':
130			xdp_flags |= XDP_FLAGS_SKB_MODE;
131			break;
132		default:
133			usage(basename(argv[0]));
134			return 1;
135		}
136	}
137
138	if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
139		xdp_flags |= XDP_FLAGS_DRV_MODE;
140
141	if (optind == argc) {
142		usage(basename(argv[0]));
143		return 1;
144	}
145
146	if (setrlimit(RLIMIT_MEMLOCK, &r)) {
147		perror("setrlimit(RLIMIT_MEMLOCK)");
148		return 1;
149	}
150
151	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
152	prog_load_attr.file = filename;
153
154	if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
155		return 1;
156
157	if (!prog_fd) {
158		printf("bpf_prog_load_xattr: %s\n", strerror(errno));
159		return 1;
160	}
161
162	map = bpf_map__next(NULL, obj);
163	if (!map) {
164		printf("finding a map in obj file failed\n");
165		return 1;
166	}
167	map_fd = bpf_map__fd(map);
168
169	if_idx = if_nametoindex(argv[optind]);
170	if (!if_idx)
171		if_idx = strtoul(argv[optind], NULL, 0);
172
173	if (!if_idx) {
174		fprintf(stderr, "Invalid ifname\n");
175		return 1;
176	}
177	if_name = argv[optind];
178	err = do_attach(if_idx, prog_fd, if_name);
179	if (err)
180		return err;
181
182	if (signal(SIGINT, sig_handler) ||
183	    signal(SIGHUP, sig_handler) ||
184	    signal(SIGTERM, sig_handler)) {
185		perror("signal");
186		return 1;
187	}
188
189	pb_opts.sample_cb = print_bpf_output;
190	pb = perf_buffer__new(map_fd, 8, &pb_opts);
191	err = libbpf_get_error(pb);
192	if (err) {
193		perror("perf_buffer setup failed");
194		return 1;
195	}
196
197	while ((ret = perf_buffer__poll(pb, 1000)) >= 0) {
198	}
199
200	kill(0, SIGINT);
201	return ret;
202}
203