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![Toke Høiland-Jørgensen](/assets/img/avatar_default.png)
The xdp_redirect and xdp_redirect_map sample programs both load a dummy
program onto the egress interfaces. However, the unload code checks these
programs against the wrong id number, and thus refuses to unload them. Fix
the comparison to avoid this.
Fixes: 3b7a8ec2de
("samples/bpf: Check the prog id before exiting")
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
220 lines
5.5 KiB
C
220 lines
5.5 KiB
C
/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/bpf.h>
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#include <linux/if_link.h>
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#include <assert.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <unistd.h>
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#include <libgen.h>
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#include <sys/resource.h>
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#include "bpf_util.h"
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#include <bpf/bpf.h>
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#include "bpf/libbpf.h"
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static int ifindex_in;
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static int ifindex_out;
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static bool ifindex_out_xdp_dummy_attached = true;
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static __u32 prog_id;
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static __u32 dummy_prog_id;
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static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
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static int rxcnt_map_fd;
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static void int_exit(int sig)
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{
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__u32 curr_prog_id = 0;
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if (bpf_get_link_xdp_id(ifindex_in, &curr_prog_id, xdp_flags)) {
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printf("bpf_get_link_xdp_id failed\n");
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exit(1);
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}
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if (prog_id == curr_prog_id)
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bpf_set_link_xdp_fd(ifindex_in, -1, xdp_flags);
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else if (!curr_prog_id)
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printf("couldn't find a prog id on iface IN\n");
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else
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printf("program on iface IN changed, not removing\n");
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if (ifindex_out_xdp_dummy_attached) {
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curr_prog_id = 0;
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if (bpf_get_link_xdp_id(ifindex_out, &curr_prog_id,
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xdp_flags)) {
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printf("bpf_get_link_xdp_id failed\n");
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exit(1);
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}
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if (dummy_prog_id == curr_prog_id)
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bpf_set_link_xdp_fd(ifindex_out, -1, xdp_flags);
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else if (!curr_prog_id)
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printf("couldn't find a prog id on iface OUT\n");
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else
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printf("program on iface OUT changed, not removing\n");
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}
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exit(0);
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}
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static void poll_stats(int interval, int ifindex)
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{
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unsigned int nr_cpus = bpf_num_possible_cpus();
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__u64 values[nr_cpus], prev[nr_cpus];
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memset(prev, 0, sizeof(prev));
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while (1) {
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__u64 sum = 0;
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__u32 key = 0;
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int i;
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sleep(interval);
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assert(bpf_map_lookup_elem(rxcnt_map_fd, &key, values) == 0);
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for (i = 0; i < nr_cpus; i++)
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sum += (values[i] - prev[i]);
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if (sum)
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printf("ifindex %i: %10llu pkt/s\n",
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ifindex, sum / interval);
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memcpy(prev, values, sizeof(values));
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}
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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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"usage: %s [OPTS] IFINDEX_IN IFINDEX_OUT\n\n"
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"OPTS:\n"
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" -S use skb-mode\n"
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" -N enforce native mode\n"
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" -F force loading prog\n",
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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 bpf_program *prog, *dummy_prog;
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struct bpf_prog_info info = {};
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__u32 info_len = sizeof(info);
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int prog_fd, dummy_prog_fd;
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const char *optstr = "FSN";
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struct bpf_object *obj;
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int ret, opt, key = 0;
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char filename[256];
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int tx_port_map_fd;
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while ((opt = getopt(argc, argv, optstr)) != -1) {
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switch (opt) {
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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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case 'N':
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xdp_flags |= XDP_FLAGS_DRV_MODE;
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break;
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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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printf("usage: %s IFINDEX_IN IFINDEX_OUT\n", 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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ifindex_in = strtoul(argv[optind], NULL, 0);
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ifindex_out = strtoul(argv[optind + 1], NULL, 0);
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printf("input: %d output: %d\n", ifindex_in, ifindex_out);
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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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prog = bpf_program__next(NULL, obj);
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dummy_prog = bpf_program__next(prog, obj);
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if (!prog || !dummy_prog) {
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printf("finding a prog in obj file failed\n");
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return 1;
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}
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/* bpf_prog_load_xattr gives us the pointer to first prog's fd,
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* so we're missing only the fd for dummy prog
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*/
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dummy_prog_fd = bpf_program__fd(dummy_prog);
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if (prog_fd < 0 || dummy_prog_fd < 0) {
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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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tx_port_map_fd = bpf_object__find_map_fd_by_name(obj, "tx_port");
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rxcnt_map_fd = bpf_object__find_map_fd_by_name(obj, "rxcnt");
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if (tx_port_map_fd < 0 || rxcnt_map_fd < 0) {
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printf("bpf_object__find_map_fd_by_name failed\n");
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return 1;
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}
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if (bpf_set_link_xdp_fd(ifindex_in, prog_fd, xdp_flags) < 0) {
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printf("ERROR: link set xdp fd failed on %d\n", ifindex_in);
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return 1;
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}
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ret = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
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if (ret) {
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printf("can't get prog info - %s\n", strerror(errno));
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return ret;
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}
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prog_id = info.id;
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/* Loading dummy XDP prog on out-device */
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if (bpf_set_link_xdp_fd(ifindex_out, dummy_prog_fd,
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(xdp_flags | XDP_FLAGS_UPDATE_IF_NOEXIST)) < 0) {
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printf("WARN: link set xdp fd failed on %d\n", ifindex_out);
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ifindex_out_xdp_dummy_attached = false;
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}
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memset(&info, 0, sizeof(info));
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ret = bpf_obj_get_info_by_fd(dummy_prog_fd, &info, &info_len);
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if (ret) {
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printf("can't get prog info - %s\n", strerror(errno));
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return ret;
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}
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dummy_prog_id = info.id;
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signal(SIGINT, int_exit);
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signal(SIGTERM, int_exit);
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/* populate virtual to physical port map */
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ret = bpf_map_update_elem(tx_port_map_fd, &key, &ifindex_out, 0);
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if (ret) {
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perror("bpf_update_elem");
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goto out;
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}
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poll_stats(2, ifindex_out);
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out:
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return 0;
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}
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