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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* dhcpcd: BPF arp and bootp filtering
* Copyright (c) 2006-2021 Roy Marples <roy@marples.name>
* All rights reserved
* 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 AUTHOR 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 AUTHOR 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_HEADER
#define BPF_HEADER
#define BPF_EOF 0x01U
#define BPF_PARTIALCSUM 0x02U
#define BPF_BCAST 0x04U
/*
* Even though we program the BPF filter should we trust it?
* On Linux at least there is a window between opening the socket,
* binding the interface and setting the filter where we receive data.
* This data is NOT checked OR flushed and IS returned when reading.
* We have no way of flushing it other than reading these packets!
* But we don't know if they passed the filter or not ..... so we need
* to validate each and every packet that comes through ourselves as well.
* Even if Linux does fix this sorry state, who is to say other kernels
* don't have bugs causing a similar effect?
*
* As such, let's strive to keep the filters just for pattern matching
* to avoid waking dhcpcd up.
*
* If you want to be notified of any packet failing the BPF filter,
* define BPF_DEBUG below.
*/
//#define BPF_DEBUG
#include "dhcpcd.h"
struct bpf {
const struct interface *bpf_ifp;
int bpf_fd;
unsigned int bpf_flags;
void *bpf_buffer;
size_t bpf_size;
size_t bpf_len;
size_t bpf_pos;
};
extern const char *bpf_name;
size_t bpf_frame_header_len(const struct interface *);
void *bpf_frame_header_src(const struct interface *, void *, size_t *);
void *bpf_frame_header_dst(const struct interface *, void *, size_t *);
int bpf_frame_bcast(const struct interface *, const void *);
struct bpf * bpf_open(const struct interface *,
int (*)(const struct bpf *, const struct in_addr *),
const struct in_addr *);
void bpf_close(struct bpf *);
int bpf_attach(int, void *, unsigned int);
ssize_t bpf_send(const struct bpf *, uint16_t, const void *, size_t);
ssize_t bpf_read(struct bpf *, void *, size_t);
int bpf_arp(const struct bpf *, const struct in_addr *);
int bpf_bootp(const struct bpf *, const struct in_addr *);
#endif
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