1#ifndef __sack_filter_h__
2#define __sack_filter_h__
3/*-
4 * Copyright (c) 2017 Netflix, Inc.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * __FBSDID("$FreeBSD$");
28 */
29
30/*
31 * Seven entry's is carefully choosen to
32 * fit in one cache line. We can easily
33 * change this to 15 (but it gets very
34 * little extra filtering). To change it
35 * to be larger than 15 would require either
36 * sf_bits becoming a uint32_t and then you
37 * could go to 31.. or change it to a full
38 * bitstring.. It is really doubtful you
39 * will get much benefit beyond 7, in testing
40 * there was a small amount but very very small.
41 */
42#define SACK_FILTER_BLOCKS 7
43
44struct sack_filter {
45	tcp_seq sf_ack;
46	uint16_t sf_bits;
47	uint8_t sf_cur;
48	uint8_t sf_used;
49	struct sackblk sf_blks[SACK_FILTER_BLOCKS];
50};
51#ifdef _KERNEL
52void sack_filter_clear(struct sack_filter *sf, tcp_seq seq);
53int sack_filter_blks(struct sack_filter *sf, struct sackblk *in, int numblks, tcp_seq th_ack);
54
55#endif
56#endif
57