1// SPDX-License-Identifier: GPL-2.0
  2#include <error.h>
  3#include <errno.h>
  4#include <getopt.h>
  5#include <stdio.h>
  6#include <stdlib.h>
  7#include <string.h>
  8#include <sys/stat.h>
  9#include <fcntl.h>
 10#include <unistd.h>
 11#include <bpf/bpf.h>
 12#include <bpf/libbpf.h>
 13
 14#include "flow_dissector_load.h"
 15
 16const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector";
 17const char *cfg_map_name = "jmp_table";
 18bool cfg_attach = true;
 19char *cfg_prog_name;
 20char *cfg_path_name;
 21
 22static void load_and_attach_program(void)
 23{
 24	int prog_fd, ret;
 25	struct bpf_object *obj;
 26
 27	/* Use libbpf 1.0 API mode */
 28	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);
 29
 30	ret = bpf_flow_load(&obj, cfg_path_name, cfg_prog_name,
 31			    cfg_map_name, NULL, &prog_fd, NULL);
 32	if (ret)
 33		error(1, 0, "bpf_flow_load %s", cfg_path_name);
 34
 35	ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0);
 36	if (ret)
 37		error(1, 0, "bpf_prog_attach %s", cfg_path_name);
 38
 39	ret = bpf_object__pin(obj, cfg_pin_path);
 40	if (ret)
 41		error(1, 0, "bpf_object__pin %s", cfg_pin_path);
 42}
 43
 44static void detach_program(void)
 45{
 46	char command[64];
 47	int ret;
 48
 49	ret = bpf_prog_detach(0, BPF_FLOW_DISSECTOR);
 50	if (ret)
 51		error(1, 0, "bpf_prog_detach");
 52
 53	/* To unpin, it is necessary and sufficient to just remove this dir */
 54	sprintf(command, "rm -r %s", cfg_pin_path);
 55	ret = system(command);
 56	if (ret)
 57		error(1, errno, "%s", command);
 58}
 59
 60static void parse_opts(int argc, char **argv)
 61{
 62	bool attach = false;
 63	bool detach = false;
 64	int c;
 65
 66	while ((c = getopt(argc, argv, "adp:s:")) != -1) {
 67		switch (c) {
 68		case 'a':
 69			if (detach)
 70				error(1, 0, "attach/detach are exclusive");
 71			attach = true;
 72			break;
 73		case 'd':
 74			if (attach)
 75				error(1, 0, "attach/detach are exclusive");
 76			detach = true;
 77			break;
 78		case 'p':
 79			if (cfg_path_name)
 80				error(1, 0, "only one path can be given");
 81
 82			cfg_path_name = optarg;
 83			break;
 84		case 's':
 85			if (cfg_prog_name)
 86				error(1, 0, "only one prog can be given");
 87
 88			cfg_prog_name = optarg;
 89			break;
 90		}
 91	}
 92
 93	if (detach)
 94		cfg_attach = false;
 95
 96	if (cfg_attach && !cfg_path_name)
 97		error(1, 0, "must provide a path to the BPF program");
 98
 99	if (cfg_attach && !cfg_prog_name)
100		error(1, 0, "must provide a section name");
101}
102
103int main(int argc, char **argv)
104{
105	parse_opts(argc, argv);
106	if (cfg_attach)
107		load_and_attach_program();
108	else
109		detach_program();
110	return 0;
111}