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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) 2006-2019 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_READING (1U << 0) | |||||
| #define BPF_EOF (1U << 1) | |||||
| #define BPF_PARTIALCSUM (1U << 2) | |||||
| #define BPF_BCAST (1U << 3) | |||||
| /* | |||||
| * 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" | |||||
| extern const char *bpf_name; | |||||
| size_t bpf_frame_header_len(const struct interface *); | |||||
| int bpf_frame_bcast(const struct interface *, const char *frame); | |||||
| int bpf_open(struct interface *, int (*)(struct interface *, int)); | |||||
| int bpf_close(struct interface *, int); | |||||
| int bpf_attach(int, void *, unsigned int); | |||||
| ssize_t bpf_send(const struct interface *, int, uint16_t, const void *, size_t); | |||||
| ssize_t bpf_read(struct interface *, int, void *, size_t, unsigned int *); | |||||
| int bpf_arp(struct interface *, int); | |||||
| int bpf_bootp(struct interface *, int); | |||||
| #endif | |||||