text: // SPDX-License-Identifier: GPL-2.0
  #include <stdio.h>
  #include <assert.h>
  #include <linux/bpf.h>
  #include "libbpf.h"
  #include "bpf_load.h"
  #include "sock_example.h"
  #include <unistd.h>
  #include <arpa/inet.h>
  #include <sys/resource.h>
  
  struct pair {
  	__u64 packets;
  	__u64 bytes;
  };
  
  int main(int ac, char **argv)
  {
  	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
  	char filename[256];
  	FILE *f;
  	int i, sock;
  
  	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
  	setrlimit(RLIMIT_MEMLOCK, &r);
  
  	if (load_bpf_file(filename)) {
  		printf("%s", bpf_log_buf);
  		return 1;
  	}
  
  	sock = open_raw_sock("lo");
  
  	assert(setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, prog_fd,
  			  sizeof(prog_fd[0])) == 0);
  
  	f = popen("ping -c5 localhost", "r");
  	(void) f;
  
  	for (i = 0; i < 5; i++) {
  		int key = 0, next_key;
  		struct pair value;
  
  		while (bpf_map_get_next_key(map_fd[0], &key, &next_key) == 0) {
  			bpf_map_lookup_elem(map_fd[0], &next_key, &value);
  			printf("ip %s bytes %lld packets %lld\n",
  			       inet_ntoa((struct in_addr){htonl(next_key)}),
  			       value.bytes, value.packets);
  			key = next_key;
  		}
  		sleep(1);
  	}
  	return 0;
  }
  