tools: bpftool: detect sub-programs from the eBPF sequence

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

/*

 * Copyright (C) 2018 Netronome Systems, Inc.

 *

 * This software is dual licensed under the GNU General License Version 2,

 * June 1991 as shown in the file COPYING in the top-level directory of this

 * source tree or the BSD 2-Clause License provided below.  You have the

 * option to license this software under the complete terms of either license.

 *

 * The BSD 2-Clause License:

 *

 *     Redistribution and use in source and binary forms, with or

 *     without modification, are permitted provided that the following

 *     conditions are met:

 *

 *      1. Redistributions of source code must retain the above

 *         copyright notice, this list of conditions and the following

 *         disclaimer.

 *

 *      2. Redistributions in binary form must reproduce the above

 *         copyright notice, this list of conditions and the following

 *         disclaimer in the documentation and/or other materials

 *         provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

#include <linux/list.h>

#include <stdlib.h>

#include <string.h>

#include "cfg.h"

#include "main.h"

struct cfg {

	struct list_head funcs;

	int func_num;

};

struct func_node {

	struct list_head l;

	struct bpf_insn *start;

	struct bpf_insn *end;

	int idx;

};

#define func_prev(func)		list_prev_entry(func, l)

#define func_next(func)		list_next_entry(func, l)

#define cfg_first_func(cfg)	\

	list_first_entry(&cfg->funcs, struct func_node, l)

#define cfg_last_func(cfg)	\

	list_last_entry(&cfg->funcs, struct func_node, l)

static struct func_node *cfg_append_func(struct cfg *cfg, struct bpf_insn *insn)

{

	struct func_node *new_func, *func;

	list_for_each_entry(func, &cfg->funcs, l) {

		if (func->start == insn)

			return func;

		else if (func->start > insn)

			break;

	}

	func = func_prev(func);

	new_func = calloc(1, sizeof(*new_func));

	if (!new_func) {

		p_err("OOM when allocating FUNC node");

		return NULL;

	}

	new_func->start = insn;

	new_func->idx = cfg->func_num;

	list_add(&new_func->l, &func->l);

	cfg->func_num++;

	return new_func;

}

static bool cfg_partition_funcs(struct cfg *cfg, struct bpf_insn *cur,

				struct bpf_insn *end)

{

	struct func_node *func, *last_func;

	func = cfg_append_func(cfg, cur);

	if (!func)

		return true;

	for (; cur < end; cur++) {

		if (cur->code != (BPF_JMP | BPF_CALL))

			continue;

		if (cur->src_reg != BPF_PSEUDO_CALL)

			continue;

		func = cfg_append_func(cfg, cur + cur->off + 1);

		if (!func)

			return true;

	}

	last_func = cfg_last_func(cfg);

	last_func->end = end - 1;

	func = cfg_first_func(cfg);

	list_for_each_entry_from(func, &last_func->l, l) {

		func->end = func_next(func)->start - 1;

	}

	return false;

}

static bool cfg_build(struct cfg *cfg, struct bpf_insn *insn, unsigned int len)

{

	int cnt = len / sizeof(*insn);

	INIT_LIST_HEAD(&cfg->funcs);

	return cfg_partition_funcs(cfg, insn, insn + cnt);

}

static void cfg_destroy(struct cfg *cfg)

{

	struct func_node *func, *func2;

	list_for_each_entry_safe(func, func2, &cfg->funcs, l) {

		list_del(&func->l);

		free(func);

	}

}

void dump_xlated_cfg(void *buf, unsigned int len)

{

	struct bpf_insn *insn = buf;

	struct cfg cfg;

	memset(&cfg, 0, sizeof(cfg));

	if (cfg_build(&cfg, insn, len))

		return;

	cfg_destroy(&cfg);

}

// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

/*

 * Copyright (C) 2018 Netronome Systems, Inc.

 *

 * This software is dual licensed under the GNU General License Version 2,

 * June 1991 as shown in the file COPYING in the top-level directory of this

 * source tree or the BSD 2-Clause License provided below.  You have the

 * option to license this software under the complete terms of either license.

 *

 * The BSD 2-Clause License:

 *

 *     Redistribution and use in source and binary forms, with or

 *     without modification, are permitted provided that the following

 *     conditions are met:

 *

 *      1. Redistributions of source code must retain the above

 *         copyright notice, this list of conditions and the following

 *         disclaimer.

 *

 *      2. Redistributions in binary form must reproduce the above

 *         copyright notice, this list of conditions and the following

 *         disclaimer in the documentation and/or other materials

 *         provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE

 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

 * POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef __BPF_TOOL_CFG_H

#define __BPF_TOOL_CFG_H

void dump_xlated_cfg(void *buf, unsigned int len);

#endif /* __BPF_TOOL_CFG_H */