forked from Minki/linux
3b7a8ec2de
Check the program id within the signal handler on polling xdp samples that were previously converted to libbpf usage. Avoid the situation of unloading the program that was not attached by sample that is exiting. Handle also the case where bpf_get_link_xdp_id didn't exit with an error but the xdp program was not found on an interface. Reported-by: Michal Papaj <michal.papaj@intel.com> Reported-by: Jakub Spizewski <jakub.spizewski@intel.com> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
225 lines
4.6 KiB
C
225 lines
4.6 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 <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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#include "trace_helpers.h"
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#define MAX_CPUS 128
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static int pmu_fds[MAX_CPUS], if_idx;
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static struct perf_event_mmap_page *headers[MAX_CPUS];
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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 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, 0);
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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, 0);
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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 int print_bpf_output(void *data, int 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",
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e->cookie, size);
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return LIBBPF_PERF_EVENT_ERROR;
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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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return LIBBPF_PERF_EVENT_CONT;
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}
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static void test_bpf_perf_event(int map_fd, int num)
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{
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struct perf_event_attr attr = {
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.sample_type = PERF_SAMPLE_RAW,
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.type = PERF_TYPE_SOFTWARE,
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.config = PERF_COUNT_SW_BPF_OUTPUT,
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.wakeup_events = 1, /* get an fd notification for every event */
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};
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int i;
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for (i = 0; i < num; i++) {
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int key = i;
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pmu_fds[i] = sys_perf_event_open(&attr, -1/*pid*/, i/*cpu*/,
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-1/*group_fd*/, 0);
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assert(pmu_fds[i] >= 0);
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assert(bpf_map_update_elem(map_fd, &key,
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&pmu_fds[i], BPF_ANY) == 0);
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ioctl(pmu_fds[i], PERF_EVENT_IOC_ENABLE, 0);
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}
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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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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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const char *optstr = "F";
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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, i;
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int numcpus;
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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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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 (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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numcpus = get_nprocs();
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if (numcpus > MAX_CPUS)
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numcpus = MAX_CPUS;
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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("load_bpf_file: %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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test_bpf_perf_event(map_fd, numcpus);
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for (i = 0; i < numcpus; i++)
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if (perf_event_mmap_header(pmu_fds[i], &headers[i]) < 0)
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return 1;
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ret = perf_event_poller_multi(pmu_fds, headers, numcpus,
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print_bpf_output);
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kill(0, SIGINT);
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return ret;
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}
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