Differential D22012 Diff 97323 contrib/dhcpcd/src/bpf.h

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contrib/dhcpcd/src/bpf.h

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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