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![Daniel T. Lee](/assets/img/avatar_default.png)
Most of the samples were converted to use the new BTF-defined MAP as they moved to libbpf, but some of the samples were missing. Instead of using the previous BPF MAP definition, this commit refactors xdp_monitor and xdp_sample_pkts_kern MAP definition with the new BTF-defined MAP format. Also, this commit removes the max_entries attribute at PERF_EVENT_ARRAY map type. The libbpf's bpf_object__create_map() will automatically set max_entries to the maximum configured number of CPUs on the host. Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20201010181734.1109-4-danieltimlee@gmail.com
202 lines
4.1 KiB
C
202 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <linux/perf_event.h>
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#include <linux/bpf.h>
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#include <net/if.h>
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#include <errno.h>
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#include <assert.h>
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#include <sys/sysinfo.h>
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#include <sys/ioctl.h>
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#include <signal.h>
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#include <bpf/libbpf.h>
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#include <bpf/bpf.h>
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#include <sys/resource.h>
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#include <libgen.h>
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#include <linux/if_link.h>
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#include "perf-sys.h"
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static int if_idx;
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static char *if_name;
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static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
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static __u32 prog_id;
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static struct perf_buffer *pb = NULL;
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static int do_attach(int idx, int fd, const char *name)
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{
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struct bpf_prog_info info = {};
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__u32 info_len = sizeof(info);
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int err;
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err = bpf_set_link_xdp_fd(idx, fd, xdp_flags);
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if (err < 0) {
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printf("ERROR: failed to attach program to %s\n", name);
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return err;
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}
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err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
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if (err) {
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printf("can't get prog info - %s\n", strerror(errno));
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return err;
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}
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prog_id = info.id;
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return err;
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}
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static int do_detach(int idx, const char *name)
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{
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__u32 curr_prog_id = 0;
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int err = 0;
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err = bpf_get_link_xdp_id(idx, &curr_prog_id, xdp_flags);
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if (err) {
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printf("bpf_get_link_xdp_id failed\n");
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return err;
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}
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if (prog_id == curr_prog_id) {
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err = bpf_set_link_xdp_fd(idx, -1, xdp_flags);
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if (err < 0)
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printf("ERROR: failed to detach prog from %s\n", name);
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} else if (!curr_prog_id) {
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printf("couldn't find a prog id on a %s\n", name);
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} else {
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printf("program on interface changed, not removing\n");
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}
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return err;
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}
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#define SAMPLE_SIZE 64
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static void print_bpf_output(void *ctx, int cpu, void *data, __u32 size)
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{
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struct {
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__u16 cookie;
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__u16 pkt_len;
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__u8 pkt_data[SAMPLE_SIZE];
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} __packed *e = data;
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int i;
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if (e->cookie != 0xdead) {
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printf("BUG cookie %x sized %d\n", e->cookie, size);
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return;
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}
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printf("Pkt len: %-5d bytes. Ethernet hdr: ", e->pkt_len);
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for (i = 0; i < 14 && i < e->pkt_len; i++)
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printf("%02x ", e->pkt_data[i]);
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printf("\n");
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}
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static void sig_handler(int signo)
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{
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do_detach(if_idx, if_name);
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perf_buffer__free(pb);
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exit(0);
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}
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static void usage(const char *prog)
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{
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fprintf(stderr,
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"%s: %s [OPTS] <ifname|ifindex>\n\n"
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"OPTS:\n"
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" -F force loading prog\n",
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__func__, prog);
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}
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int main(int argc, char **argv)
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{
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struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
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struct bpf_prog_load_attr prog_load_attr = {
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.prog_type = BPF_PROG_TYPE_XDP,
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};
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struct perf_buffer_opts pb_opts = {};
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const char *optstr = "FS";
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int prog_fd, map_fd, opt;
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struct bpf_object *obj;
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struct bpf_map *map;
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char filename[256];
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int ret, err;
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while ((opt = getopt(argc, argv, optstr)) != -1) {
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switch (opt) {
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case 'F':
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xdp_flags &= ~XDP_FLAGS_UPDATE_IF_NOEXIST;
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break;
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case 'S':
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xdp_flags |= XDP_FLAGS_SKB_MODE;
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break;
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default:
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usage(basename(argv[0]));
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return 1;
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}
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}
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if (!(xdp_flags & XDP_FLAGS_SKB_MODE))
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xdp_flags |= XDP_FLAGS_DRV_MODE;
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if (optind == argc) {
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usage(basename(argv[0]));
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return 1;
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}
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if (setrlimit(RLIMIT_MEMLOCK, &r)) {
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perror("setrlimit(RLIMIT_MEMLOCK)");
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return 1;
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}
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snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
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prog_load_attr.file = filename;
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if (bpf_prog_load_xattr(&prog_load_attr, &obj, &prog_fd))
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return 1;
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if (!prog_fd) {
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printf("bpf_prog_load_xattr: %s\n", strerror(errno));
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return 1;
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}
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map = bpf_map__next(NULL, obj);
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if (!map) {
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printf("finding a map in obj file failed\n");
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return 1;
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}
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map_fd = bpf_map__fd(map);
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if_idx = if_nametoindex(argv[optind]);
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if (!if_idx)
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if_idx = strtoul(argv[optind], NULL, 0);
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if (!if_idx) {
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fprintf(stderr, "Invalid ifname\n");
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return 1;
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}
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if_name = argv[optind];
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err = do_attach(if_idx, prog_fd, if_name);
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if (err)
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return err;
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if (signal(SIGINT, sig_handler) ||
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signal(SIGHUP, sig_handler) ||
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signal(SIGTERM, sig_handler)) {
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perror("signal");
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return 1;
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}
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pb_opts.sample_cb = print_bpf_output;
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pb = perf_buffer__new(map_fd, 8, &pb_opts);
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err = libbpf_get_error(pb);
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if (err) {
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perror("perf_buffer setup failed");
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return 1;
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}
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while ((ret = perf_buffer__poll(pb, 1000)) >= 0) {
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}
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kill(0, SIGINT);
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return ret;
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}
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