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Diffstat (limited to 'src/bpf.h')
| -rw-r--r-- | src/bpf.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/src/bpf.h b/src/bpf.h new file mode 100644 index 000000000000..40da95e61ee6 --- /dev/null +++ b/src/bpf.h @@ -0,0 +1,81 @@ +/* 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 |