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