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 <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}