// SPDX-License-Identifier: GPL-2.0

  #include <stdio.h>
  #include <assert.h>

  #include <bpf/bpf.h>

  #include <bpf/libbpf.h>

  #include "sock_example.h"

  #include <unistd.h>
  #include <arpa/inet.h>

  #include <sys/resource.h>

  struct flow_key_record {

  	__be32 src;
  	__be32 dst;
  	union {
  		__be32 ports;
  		__be16 port16[2];
  	};
  	__u32 ip_proto;
  };
  
  struct pair {
  	__u64 packets;
  	__u64 bytes;
  };
  
  int main(int argc, char **argv)
  {

  	int i, sock, key, fd, main_prog_fd, jmp_table_fd, hash_map_fd;

  	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};

  	struct bpf_program *prog;
  	struct bpf_object *obj;

  	const char *section;

  	char filename[256];
  	FILE *f;

  
  	snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);

  	setrlimit(RLIMIT_MEMLOCK, &r);

  	obj = bpf_object__open_file(filename, NULL);
  	if (libbpf_get_error(obj)) {
  		fprintf(stderr, "ERROR: opening BPF object file failed
  ");
  		return 0;
  	}
  
  	/* load BPF program */
  	if (bpf_object__load(obj)) {
  		fprintf(stderr, "ERROR: loading BPF object file failed
  ");
  		goto cleanup;
  	}
  
  	jmp_table_fd = bpf_object__find_map_fd_by_name(obj, "jmp_table");
  	hash_map_fd = bpf_object__find_map_fd_by_name(obj, "hash_map");
  	if (jmp_table_fd < 0 || hash_map_fd < 0) {
  		fprintf(stderr, "ERROR: finding a map in obj file failed
  ");
  		goto cleanup;

  	}

  	bpf_object__for_each_program(prog, obj) {
  		fd = bpf_program__fd(prog);

  		section = bpf_program__section_name(prog);
  		if (sscanf(section, "socket/%d", &key) != 1) {

  			fprintf(stderr, "ERROR: finding prog failed
  ");
  			goto cleanup;
  		}
  
  		if (key == 0)
  			main_prog_fd = fd;
  		else
  			bpf_map_update_elem(jmp_table_fd, &key, &fd, BPF_ANY);
  	}

  	sock = open_raw_sock("lo");

  	/* attach BPF program to socket */
  	assert(setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, &main_prog_fd,

  			  sizeof(__u32)) == 0);
  
  	if (argc > 1)

  		f = popen("ping -4 -c5 localhost", "r");

  	else
  		f = popen("netperf -l 4 localhost", "r");
  	(void) f;
  
  	for (i = 0; i < 5; i++) {

  		struct flow_key_record key = {}, next_key;

  		struct pair value;
  
  		sleep(1);
  		printf("IP     src.port -> dst.port               bytes      packets
  ");

  		while (bpf_map_get_next_key(hash_map_fd, &key, &next_key) == 0) {
  			bpf_map_lookup_elem(hash_map_fd, &next_key, &value);

  			printf("%s.%05d -> %s.%05d %12lld %12lld
  ",
  			       inet_ntoa((struct in_addr){htonl(next_key.src)}),
  			       next_key.port16[0],
  			       inet_ntoa((struct in_addr){htonl(next_key.dst)}),
  			       next_key.port16[1],
  			       value.bytes, value.packets);
  			key = next_key;
  		}
  	}

  
  cleanup:
  	bpf_object__close(obj);

  	return 0;
  }